Adding upstream version 1.64.0+dfsg1.upstream/1.64.0+dfsg1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

15 files changed, 9027 insertions, 0 deletions

diff --git a/vendor/dlmalloc/.cargo-checksum.json b/vendor/dlmalloc/.cargo-checksum.json
new file mode 100644
index 000000000..2d92af155
--- /dev/null
+++ b/vendor/dlmalloc/.cargo-checksum.json
@@ -0,0 +1 @@
+{"files":{"Cargo.toml":"8fb851b6256b2897689a27179da1683db869dc6625b7b0e02fba263c3c16a6b7","LICENSE-APACHE":"a60eea817514531668d7e00765731449fe14d059d3249e0bc93b36de45f759f2","LICENSE-MIT":"378f5840b258e2779c39418f3f2d7b2ba96f1c7917dd6be0713f88305dbda397","README.md":"e26786bd9af68f3065532fa85b68b8de12e0f6f455240d9a903ae947986aaa5f","build.rs":"1423186016b6fecf4dc2c3a7d506face8f644ec9c3dda035fe485d25a7e6a02d","src/dlmalloc.c":"103602c3fcbe200d5e257cdd7353d84bcc033d887bea3b245321319bf5401f47","src/dlmalloc.rs":"33111e31c78c43a0fffb618a84c0e9644f1bc830167ad25342529919ecc897ad","src/dummy.rs":"00dc39321426add094ab8efba58fb5f886726c06f032b8cb184b3d5fc71ad8ff","src/global.rs":"41a14b65509d87e4b010c3f06550bd3a1b3987e1d8703f6d915285558b4c1f43","src/lib.rs":"cb0e7add0947e2778a79a799554bd2e4765bf2a1bc6662c8cf3b5f1aecfb03ca","src/unix.rs":"9b062bc1f24ae99aa4ccbf621c020e4c3f626f70c3603e51a1fb834375b1bec4","src/wasm.rs":"ca080eab006215b4ec3d1550cb300cec02c62d3bde5e447f04dfdf74d3f87972","tests/global.rs":"6f3ca05b44fb60fd7967d2ca1d11338e177b0266d75454410b82ea704c246892","tests/smoke.rs":"e22bbf7c4d0e297428c5c58d117957e61c21f494d129e6e93f9490360631bc36"},"package":"a6fe28e0bf9357092740362502f5cc7955d8dc125ebda71dec72336c2e15c62e"}
\ No newline at end of file
diff --git a/vendor/dlmalloc/Cargo.toml b/vendor/dlmalloc/Cargo.toml
new file mode 100644
index 000000000..a8caf460d
--- /dev/null
+++ b/vendor/dlmalloc/Cargo.toml
@@ -0,0 +1,46 @@
+# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
+#
+# When uploading crates to the registry Cargo will automatically
+# "normalize" Cargo.toml files for maximal compatibility
+# with all versions of Cargo and also rewrite `path` dependencies
+# to registry (e.g., crates.io) dependencies.
+#
+# If you are reading this file be aware that the original Cargo.toml
+# will likely look very different (and much more reasonable).
+# See Cargo.toml.orig for the original contents.
+
+[package]
+name = "dlmalloc"
+version = "0.2.3"
+authors = ["Alex Crichton <alex@alexcrichton.com>"]
+description = "A Rust port of the dlmalloc allocator\n"
+homepage = "https://github.com/alexcrichton/dlmalloc-rs"
+documentation = "https://docs.rs/dlmalloc"
+readme = "README.md"
+license = "MIT/Apache-2.0"
+repository = "https://github.com/alexcrichton/dlmalloc-rs"
+[package.metadata.docs.rs]
+features = ["global"]
+[profile.release]
+debug-assertions = true
+
+[lib]
+doctest = false
+[dependencies.compiler_builtins]
+version = "0.1.0"
+optional = true
+
+[dependencies.core]
+version = "1.0.0"
+optional = true
+package = "rustc-std-workspace-core"
+[dev-dependencies.rand]
+version = "0.3"
+
+[features]
+debug = []
+global = []
+rustc-dep-of-std = ["core", "compiler_builtins/rustc-dep-of-std"]
+[target."cfg(all(unix, not(target_arch = \"wasm32\")))".dependencies.libc]
+version = "0.2"
+default-features = false
diff --git a/vendor/dlmalloc/LICENSE-APACHE b/vendor/dlmalloc/LICENSE-APACHE
new file mode 100644
index 000000000..16fe87b06
--- /dev/null
+++ b/vendor/dlmalloc/LICENSE-APACHE
@@ -0,0 +1,201 @@
+                              Apache License
+                        Version 2.0, January 2004
+                     http://www.apache.org/licenses/
+
+TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
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+Copyright [yyyy] [name of copyright owner]
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+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
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diff --git a/vendor/dlmalloc/LICENSE-MIT b/vendor/dlmalloc/LICENSE-MIT
new file mode 100644
index 000000000..39e0ed660
--- /dev/null
+++ b/vendor/dlmalloc/LICENSE-MIT
@@ -0,0 +1,25 @@
+Copyright (c) 2014 Alex Crichton
+
+Permission is hereby granted, free of charge, to any
+person obtaining a copy of this software and associated
+documentation files (the "Software"), to deal in the
+Software without restriction, including without
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+publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software
+is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice
+shall be included in all copies or substantial portions
+of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
+ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
+TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
+SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
+IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+DEALINGS IN THE SOFTWARE.
diff --git a/vendor/dlmalloc/README.md b/vendor/dlmalloc/README.md
new file mode 100644
index 000000000..8679a3b82
--- /dev/null
+++ b/vendor/dlmalloc/README.md
@@ -0,0 +1,40 @@
+# dlmalloc-rs
+
+A port of [dlmalloc] to Rust.
+
+[Documentation](https://docs.rs/dlmalloc)
+
+[dlmalloc]: http://gee.cs.oswego.edu/dl/html/malloc.html
+
+## Why dlmalloc?
+
+This crate is a port of [dlmalloc] to Rust, and doesn't rely on C. The primary
+purpose of this crate is to serve as the default allocator for Rust on the
+`wasm32-unknown-unknown` target. At the time this was written the wasm target
+didn't support C code, so it was required to have a Rust-only solution.
+
+This allocator is not the most performant by a longshot. It is primarily, I
+think, intended for being easy to port and easy to learn. I didn't dive too deep
+into the implementation when writing it, it's just a straight port of the C
+version.
+
+It's unlikely that Rust code needs to worry/interact with this allocator in
+general. Most of the time you'll be manually switching to a different allocator
+:)
+
+# License
+
+This project is licensed under either of
+
+ * Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or
+   http://www.apache.org/licenses/LICENSE-2.0)
+ * MIT license ([LICENSE-MIT](LICENSE-MIT) or
+   http://opensource.org/licenses/MIT)
+
+at your option.
+
+### Contribution
+
+Unless you explicitly state otherwise, any contribution intentionally submitted
+for inclusion in this project by you, as defined in the Apache-2.0 license,
+shall be dual licensed as above, without any additional terms or conditions.
diff --git a/vendor/dlmalloc/build.rs b/vendor/dlmalloc/build.rs
new file mode 100644
index 000000000..20aaa4f85
--- /dev/null
+++ b/vendor/dlmalloc/build.rs
@@ -0,0 +1,4 @@
+fn main() {
+    #[cfg(feature = "debug")]
+    println!("cargo:rustc-cfg=debug_assertions");
+}
diff --git a/vendor/dlmalloc/src/dlmalloc.c b/vendor/dlmalloc/src/dlmalloc.c
new file mode 100644
index 000000000..649cfbc70
--- /dev/null
+++ b/vendor/dlmalloc/src/dlmalloc.c
@@ -0,0 +1,6280 @@
+/*
+  This is a version (aka dlmalloc) of malloc/free/realloc written by
+  Doug Lea and released to the public domain, as explained at
+  http://creativecommons.org/publicdomain/zero/1.0/ Send questions,
+  comments, complaints, performance data, etc to dl@cs.oswego.edu
+
+* Version 2.8.6 Wed Aug 29 06:57:58 2012  Doug Lea
+   Note: There may be an updated version of this malloc obtainable at
+           ftp://gee.cs.oswego.edu/pub/misc/malloc.c
+         Check before installing!
+
+* Quickstart
+
+  This library is all in one file to simplify the most common usage:
+  ftp it, compile it (-O3), and link it into another program. All of
+  the compile-time options default to reasonable values for use on
+  most platforms.  You might later want to step through various
+  compile-time and dynamic tuning options.
+
+  For convenience, an include file for code using this malloc is at:
+     ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.6.h
+  You don't really need this .h file unless you call functions not
+  defined in your system include files.  The .h file contains only the
+  excerpts from this file needed for using this malloc on ANSI C/C++
+  systems, so long as you haven't changed compile-time options about
+  naming and tuning parameters.  If you do, then you can create your
+  own malloc.h that does include all settings by cutting at the point
+  indicated below. Note that you may already by default be using a C
+  library containing a malloc that is based on some version of this
+  malloc (for example in linux). You might still want to use the one
+  in this file to customize settings or to avoid overheads associated
+  with library versions.
+
+* Vital statistics:
+
+  Supported pointer/size_t representation:       4 or 8 bytes
+       size_t MUST be an unsigned type of the same width as
+       pointers. (If you are using an ancient system that declares
+       size_t as a signed type, or need it to be a different width
+       than pointers, you can use a previous release of this malloc
+       (e.g. 2.7.2) supporting these.)
+
+  Alignment:                                     8 bytes (minimum)
+       This suffices for nearly all current machines and C compilers.
+       However, you can define MALLOC_ALIGNMENT to be wider than this
+       if necessary (up to 128bytes), at the expense of using more space.
+
+  Minimum overhead per allocated chunk:   4 or  8 bytes (if 4byte sizes)
+                                          8 or 16 bytes (if 8byte sizes)
+       Each malloced chunk has a hidden word of overhead holding size
+       and status information, and additional cross-check word
+       if FOOTERS is defined.
+
+  Minimum allocated size: 4-byte ptrs:  16 bytes    (including overhead)
+                          8-byte ptrs:  32 bytes    (including overhead)
+
+       Even a request for zero bytes (i.e., malloc(0)) returns a
+       pointer to something of the minimum allocatable size.
+       The maximum overhead wastage (i.e., number of extra bytes
+       allocated than were requested in malloc) is less than or equal
+       to the minimum size, except for requests >= mmap_threshold that
+       are serviced via mmap(), where the worst case wastage is about
+       32 bytes plus the remainder from a system page (the minimal
+       mmap unit); typically 4096 or 8192 bytes.
+
+  Security: static-safe; optionally more or less
+       The "security" of malloc refers to the ability of malicious
+       code to accentuate the effects of errors (for example, freeing
+       space that is not currently malloc'ed or overwriting past the
+       ends of chunks) in code that calls malloc.  This malloc
+       guarantees not to modify any memory locations below the base of
+       heap, i.e., static variables, even in the presence of usage
+       errors.  The routines additionally detect most improper frees
+       and reallocs.  All this holds as long as the static bookkeeping
+       for malloc itself is not corrupted by some other means.  This
+       is only one aspect of security -- these checks do not, and
+       cannot, detect all possible programming errors.
+
+       If FOOTERS is defined nonzero, then each allocated chunk
+       carries an additional check word to verify that it was malloced
+       from its space.  These check words are the same within each
+       execution of a program using malloc, but differ across
+       executions, so externally crafted fake chunks cannot be
+       freed. This improves security by rejecting frees/reallocs that
+       could corrupt heap memory, in addition to the checks preventing
+       writes to statics that are always on.  This may further improve
+       security at the expense of time and space overhead.  (Note that
+       FOOTERS may also be worth using with MSPACES.)
+
+       By default detected errors cause the program to abort (calling
+       "abort()"). You can override this to instead proceed past
+       errors by defining PROCEED_ON_ERROR.  In this case, a bad free
+       has no effect, and a malloc that encounters a bad address
+       caused by user overwrites will ignore the bad address by
+       dropping pointers and indices to all known memory. This may
+       be appropriate for programs that should continue if at all
+       possible in the face of programming errors, although they may
+       run out of memory because dropped memory is never reclaimed.
+
+       If you don't like either of these options, you can define
+       CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything
+       else. And if if you are sure that your program using malloc has
+       no errors or vulnerabilities, you can define INSECURE to 1,
+       which might (or might not) provide a small performance improvement.
+
+       It is also possible to limit the maximum total allocatable
+       space, using malloc_set_footprint_limit. This is not
+       designed as a security feature in itself (calls to set limits
+       are not screened or privileged), but may be useful as one
+       aspect of a secure implementation.
+
+  Thread-safety: NOT thread-safe unless USE_LOCKS defined non-zero
+       When USE_LOCKS is defined, each public call to malloc, free,
+       etc is surrounded with a lock. By default, this uses a plain
+       pthread mutex, win32 critical section, or a spin-lock if if
+       available for the platform and not disabled by setting
+       USE_SPIN_LOCKS=0.  However, if USE_RECURSIVE_LOCKS is defined,
+       recursive versions are used instead (which are not required for
+       base functionality but may be needed in layered extensions).
+       Using a global lock is not especially fast, and can be a major
+       bottleneck.  It is designed only to provide minimal protection
+       in concurrent environments, and to provide a basis for
+       extensions.  If you are using malloc in a concurrent program,
+       consider instead using nedmalloc
+       (http://www.nedprod.com/programs/portable/nedmalloc/) or
+       ptmalloc (See http://www.malloc.de), which are derived from
+       versions of this malloc.
+
+  System requirements: Any combination of MORECORE and/or MMAP/MUNMAP
+       This malloc can use unix sbrk or any emulation (invoked using
+       the CALL_MORECORE macro) and/or mmap/munmap or any emulation
+       (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system
+       memory.  On most unix systems, it tends to work best if both
+       MORECORE and MMAP are enabled.  On Win32, it uses emulations
+       based on VirtualAlloc. It also uses common C library functions
+       like memset.
+
+  Compliance: I believe it is compliant with the Single Unix Specification
+       (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably
+       others as well.
+
+* Overview of algorithms
+
+  This is not the fastest, most space-conserving, most portable, or
+  most tunable malloc ever written. However it is among the fastest
+  while also being among the most space-conserving, portable and
+  tunable.  Consistent balance across these factors results in a good
+  general-purpose allocator for malloc-intensive programs.
+
+  In most ways, this malloc is a best-fit allocator. Generally, it
+  chooses the best-fitting existing chunk for a request, with ties
+  broken in approximately least-recently-used order. (This strategy
+  normally maintains low fragmentation.) However, for requests less
+  than 256bytes, it deviates from best-fit when there is not an
+  exactly fitting available chunk by preferring to use space adjacent
+  to that used for the previous small request, as well as by breaking
+  ties in approximately most-recently-used order. (These enhance
+  locality of series of small allocations.)  And for very large requests
+  (>= 256Kb by default), it relies on system memory mapping
+  facilities, if supported.  (This helps avoid carrying around and
+  possibly fragmenting memory used only for large chunks.)
+
+  All operations (except malloc_stats and mallinfo) have execution
+  times that are bounded by a constant factor of the number of bits in
+  a size_t, not counting any clearing in calloc or copying in realloc,
+  or actions surrounding MORECORE and MMAP that have times
+  proportional to the number of non-contiguous regions returned by
+  system allocation routines, which is often just 1. In real-time
+  applications, you can optionally suppress segment traversals using
+  NO_SEGMENT_TRAVERSAL, which assures bounded execution even when
+  system allocators return non-contiguous spaces, at the typical
+  expense of carrying around more memory and increased fragmentation.
+
+  The implementation is not very modular and seriously overuses
+  macros. Perhaps someday all C compilers will do as good a job
+  inlining modular code as can now be done by brute-force expansion,
+  but now, enough of them seem not to.
+
+  Some compilers issue a lot of warnings about code that is
+  dead/unreachable only on some platforms, and also about intentional
+  uses of negation on unsigned types. All known cases of each can be
+  ignored.
+
+  For a longer but out of date high-level description, see
+     http://gee.cs.oswego.edu/dl/html/malloc.html
+
+* MSPACES
+  If MSPACES is defined, then in addition to malloc, free, etc.,
+  this file also defines mspace_malloc, mspace_free, etc. These
+  are versions of malloc routines that take an "mspace" argument
+  obtained using create_mspace, to control all internal bookkeeping.
+  If ONLY_MSPACES is defined, only these versions are compiled.
+  So if you would like to use this allocator for only some allocations,
+  and your system malloc for others, you can compile with
+  ONLY_MSPACES and then do something like...
+    static mspace mymspace = create_mspace(0,0); // for example
+    #define mymalloc(bytes)  mspace_malloc(mymspace, bytes)
+
+  (Note: If you only need one instance of an mspace, you can instead
+  use "USE_DL_PREFIX" to relabel the global malloc.)
+
+  You can similarly create thread-local allocators by storing
+  mspaces as thread-locals. For example:
+    static __thread mspace tlms = 0;
+    void*  tlmalloc(size_t bytes) {
+      if (tlms == 0) tlms = create_mspace(0, 0);
+      return mspace_malloc(tlms, bytes);
+    }
+    void  tlfree(void* mem) { mspace_free(tlms, mem); }
+
+  Unless FOOTERS is defined, each mspace is completely independent.
+  You cannot allocate from one and free to another (although
+  conformance is only weakly checked, so usage errors are not always
+  caught). If FOOTERS is defined, then each chunk carries around a tag
+  indicating its originating mspace, and frees are directed to their
+  originating spaces. Normally, this requires use of locks.
+
+ -------------------------  Compile-time options ---------------------------
+
+Be careful in setting #define values for numerical constants of type
+size_t. On some systems, literal values are not automatically extended
+to size_t precision unless they are explicitly casted. You can also
+use the symbolic values MAX_SIZE_T, SIZE_T_ONE, etc below.
+
+WIN32                    default: defined if _WIN32 defined
+  Defining WIN32 sets up defaults for MS environment and compilers.
+  Otherwise defaults are for unix. Beware that there seem to be some
+  cases where this malloc might not be a pure drop-in replacement for
+  Win32 malloc: Random-looking failures from Win32 GDI API's (eg;
+  SetDIBits()) may be due to bugs in some video driver implementations
+  when pixel buffers are malloc()ed, and the region spans more than
+  one VirtualAlloc()ed region. Because dlmalloc uses a small (64Kb)
+  default granularity, pixel buffers may straddle virtual allocation
+  regions more often than when using the Microsoft allocator.  You can
+  avoid this by using VirtualAlloc() and VirtualFree() for all pixel
+  buffers rather than using malloc().  If this is not possible,
+  recompile this malloc with a larger DEFAULT_GRANULARITY. Note:
+  in cases where MSC and gcc (cygwin) are known to differ on WIN32,
+  conditions use _MSC_VER to distinguish them.
+
+DLMALLOC_EXPORT       default: extern
+  Defines how public APIs are declared. If you want to export via a
+  Windows DLL, you might define this as
+    #define DLMALLOC_EXPORT extern  __declspec(dllexport)
+  If you want a POSIX ELF shared object, you might use
+    #define DLMALLOC_EXPORT extern __attribute__((visibility("default")))
+
+MALLOC_ALIGNMENT         default: (size_t)(2 * sizeof(void *))
+  Controls the minimum alignment for malloc'ed chunks.  It must be a
+  power of two and at least 8, even on machines for which smaller
+  alignments would suffice. It may be defined as larger than this
+  though. Note however that code and data structures are optimized for
+  the case of 8-byte alignment.
+
+MSPACES                  default: 0 (false)
+  If true, compile in support for independent allocation spaces.
+  This is only supported if HAVE_MMAP is true.
+
+ONLY_MSPACES             default: 0 (false)
+  If true, only compile in mspace versions, not regular versions.
+
+USE_LOCKS                default: 0 (false)
+  Causes each call to each public routine to be surrounded with
+  pthread or WIN32 mutex lock/unlock. (If set true, this can be
+  overridden on a per-mspace basis for mspace versions.) If set to a
+  non-zero value other than 1, locks are used, but their
+  implementation is left out, so lock functions must be supplied manually,
+  as described below.
+
+USE_SPIN_LOCKS           default: 1 iff USE_LOCKS and spin locks available
+  If true, uses custom spin locks for locking. This is currently
+  supported only gcc >= 4.1, older gccs on x86 platforms, and recent
+  MS compilers.  Otherwise, posix locks or win32 critical sections are
+  used.
+
+USE_RECURSIVE_LOCKS      default: not defined
+  If defined nonzero, uses recursive (aka reentrant) locks, otherwise
+  uses plain mutexes. This is not required for malloc proper, but may
+  be needed for layered allocators such as nedmalloc.
+
+LOCK_AT_FORK            default: not defined
+  If defined nonzero, performs pthread_atfork upon initialization
+  to initialize child lock while holding parent lock. The implementation
+  assumes that pthread locks (not custom locks) are being used. In other
+  cases, you may need to customize the implementation.
+
+FOOTERS                  default: 0
+  If true, provide extra checking and dispatching by placing
+  information in the footers of allocated chunks. This adds
+  space and time overhead.
+
+INSECURE                 default: 0
+  If true, omit checks for usage errors and heap space overwrites.
+
+USE_DL_PREFIX            default: NOT defined
+  Causes compiler to prefix all public routines with the string 'dl'.
+  This can be useful when you only want to use this malloc in one part
+  of a program, using your regular system malloc elsewhere.
+
+MALLOC_INSPECT_ALL       default: NOT defined
+  If defined, compiles malloc_inspect_all and mspace_inspect_all, that
+  perform traversal of all heap space.  Unless access to these
+  functions is otherwise restricted, you probably do not want to
+  include them in secure implementations.
+
+ABORT                    default: defined as abort()
+  Defines how to abort on failed checks.  On most systems, a failed
+  check cannot die with an "assert" or even print an informative
+  message, because the underlying print routines in turn call malloc,
+  which will fail again.  Generally, the best policy is to simply call
+  abort(). It's not very useful to do more than this because many
+  errors due to overwriting will show up as address faults (null, odd
+  addresses etc) rather than malloc-triggered checks, so will also
+  abort.  Also, most compilers know that abort() does not return, so
+  can better optimize code conditionally calling it.
+
+PROCEED_ON_ERROR           default: defined as 0 (false)
+  Controls whether detected bad addresses cause them to bypassed
+  rather than aborting. If set, detected bad arguments to free and
+  realloc are ignored. And all bookkeeping information is zeroed out
+  upon a detected overwrite of freed heap space, thus losing the
+  ability to ever return it from malloc again, but enabling the
+  application to proceed. If PROCEED_ON_ERROR is defined, the
+  static variable malloc_corruption_error_count is compiled in
+  and can be examined to see if errors have occurred. This option
+  generates slower code than the default abort policy.
+
+DEBUG                    default: NOT defined
+  The DEBUG setting is mainly intended for people trying to modify
+  this code or diagnose problems when porting to new platforms.
+  However, it may also be able to better isolate user errors than just
+  using runtime checks.  The assertions in the check routines spell
+  out in more detail the assumptions and invariants underlying the
+  algorithms.  The checking is fairly extensive, and will slow down
+  execution noticeably. Calling malloc_stats or mallinfo with DEBUG
+  set will attempt to check every non-mmapped allocated and free chunk
+  in the course of computing the summaries.
+
+ABORT_ON_ASSERT_FAILURE   default: defined as 1 (true)
+  Debugging assertion failures can be nearly impossible if your
+  version of the assert macro causes malloc to be called, which will
+  lead to a cascade of further failures, blowing the runtime stack.
+  ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(),
+  which will usually make debugging easier.
+
+MALLOC_FAILURE_ACTION     default: sets errno to ENOMEM, or no-op on win32
+  The action to take before "return 0" when malloc fails to be able to
+  return memory because there is none available.
+
+HAVE_MORECORE             default: 1 (true) unless win32 or ONLY_MSPACES
+  True if this system supports sbrk or an emulation of it.
+
+MORECORE                  default: sbrk
+  The name of the sbrk-style system routine to call to obtain more
+  memory.  See below for guidance on writing custom MORECORE
+  functions. The type of the argument to sbrk/MORECORE varies across
+  systems.  It cannot be size_t, because it supports negative
+  arguments, so it is normally the signed type of the same width as
+  size_t (sometimes declared as "intptr_t").  It doesn't much matter
+  though. Internally, we only call it with arguments less than half
+  the max value of a size_t, which should work across all reasonable
+  possibilities, although sometimes generating compiler warnings.
+
+MORECORE_CONTIGUOUS       default: 1 (true) if HAVE_MORECORE
+  If true, take advantage of fact that consecutive calls to MORECORE
+  with positive arguments always return contiguous increasing
+  addresses.  This is true of unix sbrk. It does not hurt too much to
+  set it true anyway, since malloc copes with non-contiguities.
+  Setting it false when definitely non-contiguous saves time
+  and possibly wasted space it would take to discover this though.
+
+MORECORE_CANNOT_TRIM      default: NOT defined
+  True if MORECORE cannot release space back to the system when given
+  negative arguments. This is generally necessary only if you are
+  using a hand-crafted MORECORE function that cannot handle negative
+  arguments.
+
+NO_SEGMENT_TRAVERSAL       default: 0
+  If non-zero, suppresses traversals of memory segments
+  returned by either MORECORE or CALL_MMAP. This disables
+  merging of segments that are contiguous, and selectively
+  releasing them to the OS if unused, but bounds execution times.
+
+HAVE_MMAP                 default: 1 (true)
+  True if this system supports mmap or an emulation of it.  If so, and
+  HAVE_MORECORE is not true, MMAP is used for all system
+  allocation. If set and HAVE_MORECORE is true as well, MMAP is
+  primarily used to directly allocate very large blocks. It is also
+  used as a backup strategy in cases where MORECORE fails to provide
+  space from system. Note: A single call to MUNMAP is assumed to be
+  able to unmap memory that may have be allocated using multiple calls
+  to MMAP, so long as they are adjacent.
+
+HAVE_MREMAP               default: 1 on linux, else 0
+  If true realloc() uses mremap() to re-allocate large blocks and
+  extend or shrink allocation spaces.
+
+MMAP_CLEARS               default: 1 except on WINCE.
+  True if mmap clears memory so calloc doesn't need to. This is true
+  for standard unix mmap using /dev/zero and on WIN32 except for WINCE.
+
+USE_BUILTIN_FFS            default: 0 (i.e., not used)
+  Causes malloc to use the builtin ffs() function to compute indices.
+  Some compilers may recognize and intrinsify ffs to be faster than the
+  supplied C version. Also, the case of x86 using gcc is special-cased
+  to an asm instruction, so is already as fast as it can be, and so
+  this setting has no effect. Similarly for Win32 under recent MS compilers.
+  (On most x86s, the asm version is only slightly faster than the C version.)
+
+malloc_getpagesize         default: derive from system includes, or 4096.
+  The system page size. To the extent possible, this malloc manages
+  memory from the system in page-size units.  This may be (and
+  usually is) a function rather than a constant. This is ignored
+  if WIN32, where page size is determined using getSystemInfo during
+  initialization.
+
+USE_DEV_RANDOM             default: 0 (i.e., not used)
+  Causes malloc to use /dev/random to initialize secure magic seed for
+  stamping footers. Otherwise, the current time is used.
+
+NO_MALLINFO                default: 0
+  If defined, don't compile "mallinfo". This can be a simple way
+  of dealing with mismatches between system declarations and
+  those in this file.
+
+MALLINFO_FIELD_TYPE        default: size_t
+  The type of the fields in the mallinfo struct. This was originally
+  defined as "int" in SVID etc, but is more usefully defined as
+  size_t. The value is used only if  HAVE_USR_INCLUDE_MALLOC_H is not set
+
+NO_MALLOC_STATS            default: 0
+  If defined, don't compile "malloc_stats". This avoids calls to
+  fprintf and bringing in stdio dependencies you might not want.
+
+REALLOC_ZERO_BYTES_FREES    default: not defined
+  This should be set if a call to realloc with zero bytes should
+  be the same as a call to free. Some people think it should. Otherwise,
+  since this malloc returns a unique pointer for malloc(0), so does
+  realloc(p, 0).
+
+LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H
+LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H,  LACKS_ERRNO_H
+LACKS_STDLIB_H LACKS_SCHED_H LACKS_TIME_H  default: NOT defined unless on WIN32
+  Define these if your system does not have these header files.
+  You might need to manually insert some of the declarations they provide.
+
+DEFAULT_GRANULARITY        default: page size if MORECORE_CONTIGUOUS,
+                                system_info.dwAllocationGranularity in WIN32,
+                                otherwise 64K.
+      Also settable using mallopt(M_GRANULARITY, x)
+  The unit for allocating and deallocating memory from the system.  On
+  most systems with contiguous MORECORE, there is no reason to
+  make this more than a page. However, systems with MMAP tend to
+  either require or encourage larger granularities.  You can increase
+  this value to prevent system allocation functions to be called so
+  often, especially if they are slow.  The value must be at least one
+  page and must be a power of two.  Setting to 0 causes initialization
+  to either page size or win32 region size.  (Note: In previous
+  versions of malloc, the equivalent of this option was called
+  "TOP_PAD")
+
+DEFAULT_TRIM_THRESHOLD    default: 2MB
+      Also settable using mallopt(M_TRIM_THRESHOLD, x)
+  The maximum amount of unused top-most memory to keep before
+  releasing via malloc_trim in free().  Automatic trimming is mainly
+  useful in long-lived programs using contiguous MORECORE.  Because
+  trimming via sbrk can be slow on some systems, and can sometimes be
+  wasteful (in cases where programs immediately afterward allocate
+  more large chunks) the value should be high enough so that your
+  overall system performance would improve by releasing this much
+  memory.  As a rough guide, you might set to a value close to the
+  average size of a process (program) running on your system.
+  Releasing this much memory would allow such a process to run in
+  memory.  Generally, it is worth tuning trim thresholds when a
+  program undergoes phases where several large chunks are allocated
+  and released in ways that can reuse each other's storage, perhaps
+  mixed with phases where there are no such chunks at all. The trim
+  value must be greater than page size to have any useful effect.  To
+  disable trimming completely, you can set to MAX_SIZE_T. Note that the trick
+  some people use of mallocing a huge space and then freeing it at
+  program startup, in an attempt to reserve system memory, doesn't
+  have the intended effect under automatic trimming, since that memory
+  will immediately be returned to the system.
+
+DEFAULT_MMAP_THRESHOLD       default: 256K
+      Also settable using mallopt(M_MMAP_THRESHOLD, x)
+  The request size threshold for using MMAP to directly service a
+  request. Requests of at least this size that cannot be allocated
+  using already-existing space will be serviced via mmap.  (If enough
+  normal freed space already exists it is used instead.)  Using mmap
+  segregates relatively large chunks of memory so that they can be
+  individually obtained and released from the host system. A request
+  serviced through mmap is never reused by any other request (at least
+  not directly; the system may just so happen to remap successive
+  requests to the same locations).  Segregating space in this way has
+  the benefits that: Mmapped space can always be individually released
+  back to the system, which helps keep the system level memory demands
+  of a long-lived program low.  Also, mapped memory doesn't become
+  `locked' between other chunks, as can happen with normally allocated
+  chunks, which means that even trimming via malloc_trim would not
+  release them.  However, it has the disadvantage that the space
+  cannot be reclaimed, consolidated, and then used to service later
+  requests, as happens with normal chunks.  The advantages of mmap
+  nearly always outweigh disadvantages for "large" chunks, but the
+  value of "large" may vary across systems.  The default is an
+  empirically derived value that works well in most systems. You can
+  disable mmap by setting to MAX_SIZE_T.
+
+MAX_RELEASE_CHECK_RATE   default: 4095 unless not HAVE_MMAP
+  The number of consolidated frees between checks to release
+  unused segments when freeing. When using non-contiguous segments,
+  especially with multiple mspaces, checking only for topmost space
+  doesn't always suffice to trigger trimming. To compensate for this,
+  free() will, with a period of MAX_RELEASE_CHECK_RATE (or the
+  current number of segments, if greater) try to release unused
+  segments to the OS when freeing chunks that result in
+  consolidation. The best value for this parameter is a compromise
+  between slowing down frees with relatively costly checks that
+  rarely trigger versus holding on to unused memory. To effectively
+  disable, set to MAX_SIZE_T. This may lead to a very slight speed
+  improvement at the expense of carrying around more memory.
+*/
+
+/* Version identifier to allow people to support multiple versions */
+#ifndef DLMALLOC_VERSION
+#define DLMALLOC_VERSION 20806
+#endif /* DLMALLOC_VERSION */
+
+#ifndef DLMALLOC_EXPORT
+#define DLMALLOC_EXPORT extern
+#endif
+
+#ifndef WIN32
+#ifdef _WIN32
+#define WIN32 1
+#endif  /* _WIN32 */
+#ifdef _WIN32_WCE
+#define LACKS_FCNTL_H
+#define WIN32 1
+#endif /* _WIN32_WCE */
+#endif  /* WIN32 */
+#ifdef WIN32
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#include <tchar.h>
+#define HAVE_MMAP 1
+#define HAVE_MORECORE 0
+#define LACKS_UNISTD_H
+#define LACKS_SYS_PARAM_H
+#define LACKS_SYS_MMAN_H
+#define LACKS_STRING_H
+#define LACKS_STRINGS_H
+#define LACKS_SYS_TYPES_H
+#define LACKS_ERRNO_H
+#define LACKS_SCHED_H
+#ifndef MALLOC_FAILURE_ACTION
+#define MALLOC_FAILURE_ACTION
+#endif /* MALLOC_FAILURE_ACTION */
+#ifndef MMAP_CLEARS
+#ifdef _WIN32_WCE /* WINCE reportedly does not clear */
+#define MMAP_CLEARS 0
+#else
+#define MMAP_CLEARS 1
+#endif /* _WIN32_WCE */
+#endif /*MMAP_CLEARS */
+#endif  /* WIN32 */
+
+#if defined(DARWIN) || defined(_DARWIN)
+/* Mac OSX docs advise not to use sbrk; it seems better to use mmap */
+#ifndef HAVE_MORECORE
+#define HAVE_MORECORE 0
+#define HAVE_MMAP 1
+/* OSX allocators provide 16 byte alignment */
+#ifndef MALLOC_ALIGNMENT
+#define MALLOC_ALIGNMENT ((size_t)16U)
+#endif
+#endif  /* HAVE_MORECORE */
+#endif  /* DARWIN */
+
+#ifndef LACKS_SYS_TYPES_H
+#include <sys/types.h>  /* For size_t */
+#endif  /* LACKS_SYS_TYPES_H */
+
+/* The maximum possible size_t value has all bits set */
+#define MAX_SIZE_T           (~(size_t)0)
+
+#ifndef USE_LOCKS /* ensure true if spin or recursive locks set */
+#define USE_LOCKS  ((defined(USE_SPIN_LOCKS) && USE_SPIN_LOCKS != 0) || \
+                    (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0))
+#endif /* USE_LOCKS */
+
+#if USE_LOCKS /* Spin locks for gcc >= 4.1, older gcc on x86, MSC >= 1310 */
+#if ((defined(__GNUC__) &&                                              \
+      ((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) ||      \
+       defined(__i386__) || defined(__x86_64__))) ||                    \
+     (defined(_MSC_VER) && _MSC_VER>=1310))
+#ifndef USE_SPIN_LOCKS
+#define USE_SPIN_LOCKS 1
+#endif /* USE_SPIN_LOCKS */
+#elif USE_SPIN_LOCKS
+#error "USE_SPIN_LOCKS defined without implementation"
+#endif /* ... locks available... */
+#elif !defined(USE_SPIN_LOCKS)
+#define USE_SPIN_LOCKS 0
+#endif /* USE_LOCKS */
+
+#ifndef ONLY_MSPACES
+#define ONLY_MSPACES 0
+#endif  /* ONLY_MSPACES */
+#ifndef MSPACES
+#if ONLY_MSPACES
+#define MSPACES 1
+#else   /* ONLY_MSPACES */
+#define MSPACES 0
+#endif  /* ONLY_MSPACES */
+#endif  /* MSPACES */
+#ifndef MALLOC_ALIGNMENT
+#define MALLOC_ALIGNMENT ((size_t)(2 * sizeof(void *)))
+#endif  /* MALLOC_ALIGNMENT */
+#ifndef FOOTERS
+#define FOOTERS 0
+#endif  /* FOOTERS */
+#ifndef ABORT
+#define ABORT  abort()
+#endif  /* ABORT */
+#ifndef ABORT_ON_ASSERT_FAILURE
+#define ABORT_ON_ASSERT_FAILURE 1
+#endif  /* ABORT_ON_ASSERT_FAILURE */
+#ifndef PROCEED_ON_ERROR
+#define PROCEED_ON_ERROR 0
+#endif  /* PROCEED_ON_ERROR */
+
+#ifndef INSECURE
+#define INSECURE 0
+#endif  /* INSECURE */
+#ifndef MALLOC_INSPECT_ALL
+#define MALLOC_INSPECT_ALL 0
+#endif  /* MALLOC_INSPECT_ALL */
+#ifndef HAVE_MMAP
+#define HAVE_MMAP 1
+#endif  /* HAVE_MMAP */
+#ifndef MMAP_CLEARS
+#define MMAP_CLEARS 1
+#endif  /* MMAP_CLEARS */
+#ifndef HAVE_MREMAP
+#ifdef linux
+#define HAVE_MREMAP 1
+#define _GNU_SOURCE /* Turns on mremap() definition */
+#else   /* linux */
+#define HAVE_MREMAP 0
+#endif  /* linux */
+#endif  /* HAVE_MREMAP */
+#ifndef MALLOC_FAILURE_ACTION
+#define MALLOC_FAILURE_ACTION  errno = ENOMEM;
+#endif  /* MALLOC_FAILURE_ACTION */
+#ifndef HAVE_MORECORE
+#if ONLY_MSPACES
+#define HAVE_MORECORE 0
+#else   /* ONLY_MSPACES */
+#define HAVE_MORECORE 1
+#endif  /* ONLY_MSPACES */
+#endif  /* HAVE_MORECORE */
+#if !HAVE_MORECORE
+#define MORECORE_CONTIGUOUS 0
+#else   /* !HAVE_MORECORE */
+#define MORECORE_DEFAULT sbrk
+#ifndef MORECORE_CONTIGUOUS
+#define MORECORE_CONTIGUOUS 1
+#endif  /* MORECORE_CONTIGUOUS */
+#endif  /* HAVE_MORECORE */
+#ifndef DEFAULT_GRANULARITY
+#if (MORECORE_CONTIGUOUS || defined(WIN32))
+#define DEFAULT_GRANULARITY (0)  /* 0 means to compute in init_mparams */
+#else   /* MORECORE_CONTIGUOUS */
+#define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U)
+#endif  /* MORECORE_CONTIGUOUS */
+#endif  /* DEFAULT_GRANULARITY */
+#ifndef DEFAULT_TRIM_THRESHOLD
+#ifndef MORECORE_CANNOT_TRIM
+#define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U)
+#else   /* MORECORE_CANNOT_TRIM */
+#define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T
+#endif  /* MORECORE_CANNOT_TRIM */
+#endif  /* DEFAULT_TRIM_THRESHOLD */
+#ifndef DEFAULT_MMAP_THRESHOLD
+#if HAVE_MMAP
+#define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U)
+#else   /* HAVE_MMAP */
+#define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T
+#endif  /* HAVE_MMAP */
+#endif  /* DEFAULT_MMAP_THRESHOLD */
+#ifndef MAX_RELEASE_CHECK_RATE
+#if HAVE_MMAP
+#define MAX_RELEASE_CHECK_RATE 4095
+#else
+#define MAX_RELEASE_CHECK_RATE MAX_SIZE_T
+#endif /* HAVE_MMAP */
+#endif /* MAX_RELEASE_CHECK_RATE */
+#ifndef USE_BUILTIN_FFS
+#define USE_BUILTIN_FFS 0
+#endif  /* USE_BUILTIN_FFS */
+#ifndef USE_DEV_RANDOM
+#define USE_DEV_RANDOM 0
+#endif  /* USE_DEV_RANDOM */
+#ifndef NO_MALLINFO
+#define NO_MALLINFO 0
+#endif  /* NO_MALLINFO */
+#ifndef MALLINFO_FIELD_TYPE
+#define MALLINFO_FIELD_TYPE size_t
+#endif  /* MALLINFO_FIELD_TYPE */
+#ifndef NO_MALLOC_STATS
+#define NO_MALLOC_STATS 0
+#endif  /* NO_MALLOC_STATS */
+#ifndef NO_SEGMENT_TRAVERSAL
+#define NO_SEGMENT_TRAVERSAL 0
+#endif /* NO_SEGMENT_TRAVERSAL */
+
+/*
+  mallopt tuning options.  SVID/XPG defines four standard parameter
+  numbers for mallopt, normally defined in malloc.h.  None of these
+  are used in this malloc, so setting them has no effect. But this
+  malloc does support the following options.
+*/
+
+#define M_TRIM_THRESHOLD     (-1)
+#define M_GRANULARITY        (-2)
+#define M_MMAP_THRESHOLD     (-3)
+
+/* ------------------------ Mallinfo declarations ------------------------ */
+
+#if !NO_MALLINFO
+/*
+  This version of malloc supports the standard SVID/XPG mallinfo
+  routine that returns a struct containing usage properties and
+  statistics. It should work on any system that has a
+  /usr/include/malloc.h defining struct mallinfo.  The main
+  declaration needed is the mallinfo struct that is returned (by-copy)
+  by mallinfo().  The malloinfo struct contains a bunch of fields that
+  are not even meaningful in this version of malloc.  These fields are
+  are instead filled by mallinfo() with other numbers that might be of
+  interest.
+
+  HAVE_USR_INCLUDE_MALLOC_H should be set if you have a
+  /usr/include/malloc.h file that includes a declaration of struct
+  mallinfo.  If so, it is included; else a compliant version is
+  declared below.  These must be precisely the same for mallinfo() to
+  work.  The original SVID version of this struct, defined on most
+  systems with mallinfo, declares all fields as ints. But some others
+  define as unsigned long. If your system defines the fields using a
+  type of different width than listed here, you MUST #include your
+  system version and #define HAVE_USR_INCLUDE_MALLOC_H.
+*/
+
+/* #define HAVE_USR_INCLUDE_MALLOC_H */
+
+#ifdef HAVE_USR_INCLUDE_MALLOC_H
+#include "/usr/include/malloc.h"
+#else /* HAVE_USR_INCLUDE_MALLOC_H */
+#ifndef STRUCT_MALLINFO_DECLARED
+/* HP-UX (and others?) redefines mallinfo unless _STRUCT_MALLINFO is defined */
+#define _STRUCT_MALLINFO
+#define STRUCT_MALLINFO_DECLARED 1
+struct mallinfo {
+  MALLINFO_FIELD_TYPE arena;    /* non-mmapped space allocated from system */
+  MALLINFO_FIELD_TYPE ordblks;  /* number of free chunks */
+  MALLINFO_FIELD_TYPE smblks;   /* always 0 */
+  MALLINFO_FIELD_TYPE hblks;    /* always 0 */
+  MALLINFO_FIELD_TYPE hblkhd;   /* space in mmapped regions */
+  MALLINFO_FIELD_TYPE usmblks;  /* maximum total allocated space */
+  MALLINFO_FIELD_TYPE fsmblks;  /* always 0 */
+  MALLINFO_FIELD_TYPE uordblks; /* total allocated space */
+  MALLINFO_FIELD_TYPE fordblks; /* total free space */
+  MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */
+};
+#endif /* STRUCT_MALLINFO_DECLARED */
+#endif /* HAVE_USR_INCLUDE_MALLOC_H */
+#endif /* NO_MALLINFO */
+
+/*
+  Try to persuade compilers to inline. The most critical functions for
+  inlining are defined as macros, so these aren't used for them.
+*/
+
+#ifndef FORCEINLINE
+  #if defined(__GNUC__)
+#define FORCEINLINE __inline __attribute__ ((always_inline))
+  #elif defined(_MSC_VER)
+    #define FORCEINLINE __forceinline
+  #endif
+#endif
+#ifndef NOINLINE
+  #if defined(__GNUC__)
+    #define NOINLINE __attribute__ ((noinline))
+  #elif defined(_MSC_VER)
+    #define NOINLINE __declspec(noinline)
+  #else
+    #define NOINLINE
+  #endif
+#endif
+
+#ifdef __cplusplus
+extern "C" {
+#ifndef FORCEINLINE
+ #define FORCEINLINE inline
+#endif
+#endif /* __cplusplus */
+#ifndef FORCEINLINE
+ #define FORCEINLINE
+#endif
+
+#if !ONLY_MSPACES
+
+/* ------------------- Declarations of public routines ------------------- */
+
+#ifndef USE_DL_PREFIX
+#define dlcalloc               calloc
+#define dlfree                 free
+#define dlmalloc               malloc
+#define dlmemalign             memalign
+#define dlposix_memalign       posix_memalign
+#define dlrealloc              realloc
+#define dlrealloc_in_place     realloc_in_place
+#define dlvalloc               valloc
+#define dlpvalloc              pvalloc
+#define dlmallinfo             mallinfo
+#define dlmallopt              mallopt
+#define dlmalloc_trim          malloc_trim
+#define dlmalloc_stats         malloc_stats
+#define dlmalloc_usable_size   malloc_usable_size
+#define dlmalloc_footprint     malloc_footprint
+#define dlmalloc_max_footprint malloc_max_footprint
+#define dlmalloc_footprint_limit malloc_footprint_limit
+#define dlmalloc_set_footprint_limit malloc_set_footprint_limit
+#define dlmalloc_inspect_all   malloc_inspect_all
+#define dlindependent_calloc   independent_calloc
+#define dlindependent_comalloc independent_comalloc
+#define dlbulk_free            bulk_free
+#endif /* USE_DL_PREFIX */
+
+/*
+  malloc(size_t n)
+  Returns a pointer to a newly allocated chunk of at least n bytes, or
+  null if no space is available, in which case errno is set to ENOMEM
+  on ANSI C systems.
+
+  If n is zero, malloc returns a minimum-sized chunk. (The minimum
+  size is 16 bytes on most 32bit systems, and 32 bytes on 64bit
+  systems.)  Note that size_t is an unsigned type, so calls with
+  arguments that would be negative if signed are interpreted as
+  requests for huge amounts of space, which will often fail. The
+  maximum supported value of n differs across systems, but is in all
+  cases less than the maximum representable value of a size_t.
+*/
+DLMALLOC_EXPORT void* dlmalloc(size_t);
+
+/*
+  free(void* p)
+  Releases the chunk of memory pointed to by p, that had been previously
+  allocated using malloc or a related routine such as realloc.
+  It has no effect if p is null. If p was not malloced or already
+  freed, free(p) will by default cause the current program to abort.
+*/
+DLMALLOC_EXPORT void  dlfree(void*);
+
+/*
+  calloc(size_t n_elements, size_t element_size);
+  Returns a pointer to n_elements * element_size bytes, with all locations
+  set to zero.
+*/
+DLMALLOC_EXPORT void* dlcalloc(size_t, size_t);
+
+/*
+  realloc(void* p, size_t n)
+  Returns a pointer to a chunk of size n that contains the same data
+  as does chunk p up to the minimum of (n, p's size) bytes, or null
+  if no space is available.
+
+  The returned pointer may or may not be the same as p. The algorithm
+  prefers extending p in most cases when possible, otherwise it
+  employs the equivalent of a malloc-copy-free sequence.
+
+  If p is null, realloc is equivalent to malloc.
+
+  If space is not available, realloc returns null, errno is set (if on
+  ANSI) and p is NOT freed.
+
+  if n is for fewer bytes than already held by p, the newly unused
+  space is lopped off and freed if possible.  realloc with a size
+  argument of zero (re)allocates a minimum-sized chunk.
+
+  The old unix realloc convention of allowing the last-free'd chunk
+  to be used as an argument to realloc is not supported.
+*/
+DLMALLOC_EXPORT void* dlrealloc(void*, size_t);
+
+/*
+  realloc_in_place(void* p, size_t n)
+  Resizes the space allocated for p to size n, only if this can be
+  done without moving p (i.e., only if there is adjacent space
+  available if n is greater than p's current allocated size, or n is
+  less than or equal to p's size). This may be used instead of plain
+  realloc if an alternative allocation strategy is needed upon failure
+  to expand space; for example, reallocation of a buffer that must be
+  memory-aligned or cleared. You can use realloc_in_place to trigger
+  these alternatives only when needed.
+
+  Returns p if successful; otherwise null.
+*/
+DLMALLOC_EXPORT void* dlrealloc_in_place(void*, size_t);
+
+/*
+  memalign(size_t alignment, size_t n);
+  Returns a pointer to a newly allocated chunk of n bytes, aligned
+  in accord with the alignment argument.
+
+  The alignment argument should be a power of two. If the argument is
+  not a power of two, the nearest greater power is used.
+  8-byte alignment is guaranteed by normal malloc calls, so don't
+  bother calling memalign with an argument of 8 or less.
+
+  Overreliance on memalign is a sure way to fragment space.
+*/
+DLMALLOC_EXPORT void* dlmemalign(size_t, size_t);
+
+/*
+  int posix_memalign(void** pp, size_t alignment, size_t n);
+  Allocates a chunk of n bytes, aligned in accord with the alignment
+  argument. Differs from memalign only in that it (1) assigns the
+  allocated memory to *pp rather than returning it, (2) fails and
+  returns EINVAL if the alignment is not a power of two (3) fails and
+  returns ENOMEM if memory cannot be allocated.
+*/
+DLMALLOC_EXPORT int dlposix_memalign(void**, size_t, size_t);
+
+/*
+  valloc(size_t n);
+  Equivalent to memalign(pagesize, n), where pagesize is the page
+  size of the system. If the pagesize is unknown, 4096 is used.
+*/
+DLMALLOC_EXPORT void* dlvalloc(size_t);
+
+/*
+  mallopt(int parameter_number, int parameter_value)
+  Sets tunable parameters The format is to provide a
+  (parameter-number, parameter-value) pair.  mallopt then sets the
+  corresponding parameter to the argument value if it can (i.e., so
+  long as the value is meaningful), and returns 1 if successful else
+  0.  To workaround the fact that mallopt is specified to use int,
+  not size_t parameters, the value -1 is specially treated as the
+  maximum unsigned size_t value.
+
+  SVID/XPG/ANSI defines four standard param numbers for mallopt,
+  normally defined in malloc.h.  None of these are use in this malloc,
+  so setting them has no effect. But this malloc also supports other
+  options in mallopt. See below for details.  Briefly, supported
+  parameters are as follows (listed defaults are for "typical"
+  configurations).
+
+  Symbol            param #  default    allowed param values
+  M_TRIM_THRESHOLD     -1   2*1024*1024   any   (-1 disables)
+  M_GRANULARITY        -2     page size   any power of 2 >= page size
+  M_MMAP_THRESHOLD     -3      256*1024   any   (or 0 if no MMAP support)
+*/
+DLMALLOC_EXPORT int dlmallopt(int, int);
+
+/*
+  malloc_footprint();
+  Returns the number of bytes obtained from the system.  The total
+  number of bytes allocated by malloc, realloc etc., is less than this
+  value. Unlike mallinfo, this function returns only a precomputed
+  result, so can be called frequently to monitor memory consumption.
+  Even if locks are otherwise defined, this function does not use them,
+  so results might not be up to date.
+*/
+DLMALLOC_EXPORT size_t dlmalloc_footprint(void);
+
+/*
+  malloc_max_footprint();
+  Returns the maximum number of bytes obtained from the system. This
+  value will be greater than current footprint if deallocated space
+  has been reclaimed by the system. The peak number of bytes allocated
+  by malloc, realloc etc., is less than this value. Unlike mallinfo,
+  this function returns only a precomputed result, so can be called
+  frequently to monitor memory consumption.  Even if locks are
+  otherwise defined, this function does not use them, so results might
+  not be up to date.
+*/
+DLMALLOC_EXPORT size_t dlmalloc_max_footprint(void);
+
+/*
+  malloc_footprint_limit();
+  Returns the number of bytes that the heap is allowed to obtain from
+  the system, returning the last value returned by
+  malloc_set_footprint_limit, or the maximum size_t value if
+  never set. The returned value reflects a permission. There is no
+  guarantee that this number of bytes can actually be obtained from
+  the system.
+*/
+DLMALLOC_EXPORT size_t dlmalloc_footprint_limit();
+
+/*
+  malloc_set_footprint_limit();
+  Sets the maximum number of bytes to obtain from the system, causing
+  failure returns from malloc and related functions upon attempts to
+  exceed this value. The argument value may be subject to page
+  rounding to an enforceable limit; this actual value is returned.
+  Using an argument of the maximum possible size_t effectively
+  disables checks. If the argument is less than or equal to the
+  current malloc_footprint, then all future allocations that require
+  additional system memory will fail. However, invocation cannot
+  retroactively deallocate existing used memory.
+*/
+DLMALLOC_EXPORT size_t dlmalloc_set_footprint_limit(size_t bytes);
+
+#if MALLOC_INSPECT_ALL
+/*
+  malloc_inspect_all(void(*handler)(void *start,
+                                    void *end,
+                                    size_t used_bytes,
+                                    void* callback_arg),
+                      void* arg);
+  Traverses the heap and calls the given handler for each managed
+  region, skipping all bytes that are (or may be) used for bookkeeping
+  purposes.  Traversal does not include include chunks that have been
+  directly memory mapped. Each reported region begins at the start
+  address, and continues up to but not including the end address.  The
+  first used_bytes of the region contain allocated data. If
+  used_bytes is zero, the region is unallocated. The handler is
+  invoked with the given callback argument. If locks are defined, they
+  are held during the entire traversal. It is a bad idea to invoke
+  other malloc functions from within the handler.
+
+  For example, to count the number of in-use chunks with size greater
+  than 1000, you could write:
+  static int count = 0;
+  void count_chunks(void* start, void* end, size_t used, void* arg) {
+    if (used >= 1000) ++count;
+  }
+  then:
+    malloc_inspect_all(count_chunks, NULL);
+
+  malloc_inspect_all is compiled only if MALLOC_INSPECT_ALL is defined.
+*/
+DLMALLOC_EXPORT void dlmalloc_inspect_all(void(*handler)(void*, void *, size_t, void*),
+                           void* arg);
+
+#endif /* MALLOC_INSPECT_ALL */
+
+#if !NO_MALLINFO
+/*
+  mallinfo()
+  Returns (by copy) a struct containing various summary statistics:
+
+  arena:     current total non-mmapped bytes allocated from system
+  ordblks:   the number of free chunks
+  smblks:    always zero.
+  hblks:     current number of mmapped regions
+  hblkhd:    total bytes held in mmapped regions
+  usmblks:   the maximum total allocated space. This will be greater
+                than current total if trimming has occurred.
+  fsmblks:   always zero
+  uordblks:  current total allocated space (normal or mmapped)
+  fordblks:  total free space
+  keepcost:  the maximum number of bytes that could ideally be released
+               back to system via malloc_trim. ("ideally" means that
+               it ignores page restrictions etc.)
+
+  Because these fields are ints, but internal bookkeeping may
+  be kept as longs, the reported values may wrap around zero and
+  thus be inaccurate.
+*/
+DLMALLOC_EXPORT struct mallinfo dlmallinfo(void);
+#endif /* NO_MALLINFO */
+
+/*
+  independent_calloc(size_t n_elements, size_t element_size, void* chunks[]);
+
+  independent_calloc is similar to calloc, but instead of returning a
+  single cleared space, it returns an array of pointers to n_elements
+  independent elements that can hold contents of size elem_size, each
+  of which starts out cleared, and can be independently freed,
+  realloc'ed etc. The elements are guaranteed to be adjacently
+  allocated (this is not guaranteed to occur with multiple callocs or
+  mallocs), which may also improve cache locality in some
+  applications.
+
+  The "chunks" argument is optional (i.e., may be null, which is
+  probably the most typical usage). If it is null, the returned array
+  is itself dynamically allocated and should also be freed when it is
+  no longer needed. Otherwise, the chunks array must be of at least
+  n_elements in length. It is filled in with the pointers to the
+  chunks.
+
+  In either case, independent_calloc returns this pointer array, or
+  null if the allocation failed.  If n_elements is zero and "chunks"
+  is null, it returns a chunk representing an array with zero elements
+  (which should be freed if not wanted).
+
+  Each element must be freed when it is no longer needed. This can be
+  done all at once using bulk_free.
+
+  independent_calloc simplifies and speeds up implementations of many
+  kinds of pools.  It may also be useful when constructing large data
+  structures that initially have a fixed number of fixed-sized nodes,
+  but the number is not known at compile time, and some of the nodes
+  may later need to be freed. For example:
+
+  struct Node { int item; struct Node* next; };
+
+  struct Node* build_list() {
+    struct Node** pool;
+    int n = read_number_of_nodes_needed();
+    if (n <= 0) return 0;
+    pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0);
+    if (pool == 0) die();
+    // organize into a linked list...
+    struct Node* first = pool[0];
+    for (i = 0; i < n-1; ++i)
+      pool[i]->next = pool[i+1];
+    free(pool);     // Can now free the array (or not, if it is needed later)
+    return first;
+  }
+*/
+DLMALLOC_EXPORT void** dlindependent_calloc(size_t, size_t, void**);
+
+/*
+  independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]);
+
+  independent_comalloc allocates, all at once, a set of n_elements
+  chunks with sizes indicated in the "sizes" array.    It returns
+  an array of pointers to these elements, each of which can be
+  independently freed, realloc'ed etc. The elements are guaranteed to
+  be adjacently allocated (this is not guaranteed to occur with
+  multiple callocs or mallocs), which may also improve cache locality
+  in some applications.
+
+  The "chunks" argument is optional (i.e., may be null). If it is null
+  the returned array is itself dynamically allocated and should also
+  be freed when it is no longer needed. Otherwise, the chunks array
+  must be of at least n_elements in length. It is filled in with the
+  pointers to the chunks.
+
+  In either case, independent_comalloc returns this pointer array, or
+  null if the allocation failed.  If n_elements is zero and chunks is
+  null, it returns a chunk representing an array with zero elements
+  (which should be freed if not wanted).
+
+  Each element must be freed when it is no longer needed. This can be
+  done all at once using bulk_free.
+
+  independent_comallac differs from independent_calloc in that each
+  element may have a different size, and also that it does not
+  automatically clear elements.
+
+  independent_comalloc can be used to speed up allocation in cases
+  where several structs or objects must always be allocated at the
+  same time.  For example:
+
+  struct Head { ... }
+  struct Foot { ... }
+
+  void send_message(char* msg) {
+    int msglen = strlen(msg);
+    size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) };
+    void* chunks[3];
+    if (independent_comalloc(3, sizes, chunks) == 0)
+      die();
+    struct Head* head = (struct Head*)(chunks[0]);
+    char*        body = (char*)(chunks[1]);
+    struct Foot* foot = (struct Foot*)(chunks[2]);
+    // ...
+  }
+
+  In general though, independent_comalloc is worth using only for
+  larger values of n_elements. For small values, you probably won't
+  detect enough difference from series of malloc calls to bother.
+
+  Overuse of independent_comalloc can increase overall memory usage,
+  since it cannot reuse existing noncontiguous small chunks that
+  might be available for some of the elements.
+*/
+DLMALLOC_EXPORT void** dlindependent_comalloc(size_t, size_t*, void**);
+
+/*
+  bulk_free(void* array[], size_t n_elements)
+  Frees and clears (sets to null) each non-null pointer in the given
+  array.  This is likely to be faster than freeing them one-by-one.
+  If footers are used, pointers that have been allocated in different
+  mspaces are not freed or cleared, and the count of all such pointers
+  is returned.  For large arrays of pointers with poor locality, it
+  may be worthwhile to sort this array before calling bulk_free.
+*/
+DLMALLOC_EXPORT size_t  dlbulk_free(void**, size_t n_elements);
+
+/*
+  pvalloc(size_t n);
+  Equivalent to valloc(minimum-page-that-holds(n)), that is,
+  round up n to nearest pagesize.
+ */
+DLMALLOC_EXPORT void*  dlpvalloc(size_t);
+
+/*
+  malloc_trim(size_t pad);
+
+  If possible, gives memory back to the system (via negative arguments
+  to sbrk) if there is unused memory at the `high' end of the malloc
+  pool or in unused MMAP segments. You can call this after freeing
+  large blocks of memory to potentially reduce the system-level memory
+  requirements of a program. However, it cannot guarantee to reduce
+  memory. Under some allocation patterns, some large free blocks of
+  memory will be locked between two used chunks, so they cannot be
+  given back to the system.
+
+  The `pad' argument to malloc_trim represents the amount of free
+  trailing space to leave untrimmed. If this argument is zero, only
+  the minimum amount of memory to maintain internal data structures
+  will be left. Non-zero arguments can be supplied to maintain enough
+  trailing space to service future expected allocations without having
+  to re-obtain memory from the system.
+
+  Malloc_trim returns 1 if it actually released any memory, else 0.
+*/
+DLMALLOC_EXPORT int  dlmalloc_trim(size_t);
+
+/*
+  malloc_stats();
+  Prints on stderr the amount of space obtained from the system (both
+  via sbrk and mmap), the maximum amount (which may be more than
+  current if malloc_trim and/or munmap got called), and the current
+  number of bytes allocated via malloc (or realloc, etc) but not yet
+  freed. Note that this is the number of bytes allocated, not the
+  number requested. It will be larger than the number requested
+  because of alignment and bookkeeping overhead. Because it includes
+  alignment wastage as being in use, this figure may be greater than
+  zero even when no user-level chunks are allocated.
+
+  The reported current and maximum system memory can be inaccurate if
+  a program makes other calls to system memory allocation functions
+  (normally sbrk) outside of malloc.
+
+  malloc_stats prints only the most commonly interesting statistics.
+  More information can be obtained by calling mallinfo.
+*/
+DLMALLOC_EXPORT void  dlmalloc_stats(void);
+
+/*
+  malloc_usable_size(void* p);
+
+  Returns the number of bytes you can actually use in
+  an allocated chunk, which may be more than you requested (although
+  often not) due to alignment and minimum size constraints.
+  You can use this many bytes without worrying about
+  overwriting other allocated objects. This is not a particularly great
+  programming practice. malloc_usable_size can be more useful in
+  debugging and assertions, for example:
+
+  p = malloc(n);
+  assert(malloc_usable_size(p) >= 256);
+*/
+size_t dlmalloc_usable_size(void*);
+
+#endif /* ONLY_MSPACES */
+
+#if MSPACES
+
+/*
+  mspace is an opaque type representing an independent
+  region of space that supports mspace_malloc, etc.
+*/
+typedef void* mspace;
+
+/*
+  create_mspace creates and returns a new independent space with the
+  given initial capacity, or, if 0, the default granularity size.  It
+  returns null if there is no system memory available to create the
+  space.  If argument locked is non-zero, the space uses a separate
+  lock to control access. The capacity of the space will grow
+  dynamically as needed to service mspace_malloc requests.  You can
+  control the sizes of incremental increases of this space by
+  compiling with a different DEFAULT_GRANULARITY or dynamically
+  setting with mallopt(M_GRANULARITY, value).
+*/
+DLMALLOC_EXPORT mspace create_mspace(size_t capacity, int locked);
+
+/*
+  destroy_mspace destroys the given space, and attempts to return all
+  of its memory back to the system, returning the total number of
+  bytes freed. After destruction, the results of access to all memory
+  used by the space become undefined.
+*/
+DLMALLOC_EXPORT size_t destroy_mspace(mspace msp);
+
+/*
+  create_mspace_with_base uses the memory supplied as the initial base
+  of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this
+  space is used for bookkeeping, so the capacity must be at least this
+  large. (Otherwise 0 is returned.) When this initial space is
+  exhausted, additional memory will be obtained from the system.
+  Destroying this space will deallocate all additionally allocated
+  space (if possible) but not the initial base.
+*/
+DLMALLOC_EXPORT mspace create_mspace_with_base(void* base, size_t capacity, int locked);
+
+/*
+  mspace_track_large_chunks controls whether requests for large chunks
+  are allocated in their own untracked mmapped regions, separate from
+  others in this mspace. By default large chunks are not tracked,
+  which reduces fragmentation. However, such chunks are not
+  necessarily released to the system upon destroy_mspace.  Enabling
+  tracking by setting to true may increase fragmentation, but avoids
+  leakage when relying on destroy_mspace to release all memory
+  allocated using this space.  The function returns the previous
+  setting.
+*/
+DLMALLOC_EXPORT int mspace_track_large_chunks(mspace msp, int enable);
+
+
+/*
+  mspace_malloc behaves as malloc, but operates within
+  the given space.
+*/
+DLMALLOC_EXPORT void* mspace_malloc(mspace msp, size_t bytes);
+
+/*
+  mspace_free behaves as free, but operates within
+  the given space.
+
+  If compiled with FOOTERS==1, mspace_free is not actually needed.
+  free may be called instead of mspace_free because freed chunks from
+  any space are handled by their originating spaces.
+*/
+DLMALLOC_EXPORT void mspace_free(mspace msp, void* mem);
+
+/*
+  mspace_realloc behaves as realloc, but operates within
+  the given space.
+
+  If compiled with FOOTERS==1, mspace_realloc is not actually
+  needed.  realloc may be called instead of mspace_realloc because
+  realloced chunks from any space are handled by their originating
+  spaces.
+*/
+DLMALLOC_EXPORT void* mspace_realloc(mspace msp, void* mem, size_t newsize);
+
+/*
+  mspace_calloc behaves as calloc, but operates within
+  the given space.
+*/
+DLMALLOC_EXPORT void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size);
+
+/*
+  mspace_memalign behaves as memalign, but operates within
+  the given space.
+*/
+DLMALLOC_EXPORT void* mspace_memalign(mspace msp, size_t alignment, size_t bytes);
+
+/*
+  mspace_independent_calloc behaves as independent_calloc, but
+  operates within the given space.
+*/
+DLMALLOC_EXPORT void** mspace_independent_calloc(mspace msp, size_t n_elements,
+                                 size_t elem_size, void* chunks[]);
+
+/*
+  mspace_independent_comalloc behaves as independent_comalloc, but
+  operates within the given space.
+*/
+DLMALLOC_EXPORT void** mspace_independent_comalloc(mspace msp, size_t n_elements,
+                                   size_t sizes[], void* chunks[]);
+
+/*
+  mspace_footprint() returns the number of bytes obtained from the
+  system for this space.
+*/
+DLMALLOC_EXPORT size_t mspace_footprint(mspace msp);
+
+/*
+  mspace_max_footprint() returns the peak number of bytes obtained from the
+  system for this space.
+*/
+DLMALLOC_EXPORT size_t mspace_max_footprint(mspace msp);
+
+
+#if !NO_MALLINFO
+/*
+  mspace_mallinfo behaves as mallinfo, but reports properties of
+  the given space.
+*/
+DLMALLOC_EXPORT struct mallinfo mspace_mallinfo(mspace msp);
+#endif /* NO_MALLINFO */
+
+/*
+  malloc_usable_size(void* p) behaves the same as malloc_usable_size;
+*/
+DLMALLOC_EXPORT size_t mspace_usable_size(const void* mem);
+
+/*
+  mspace_malloc_stats behaves as malloc_stats, but reports
+  properties of the given space.
+*/
+DLMALLOC_EXPORT void mspace_malloc_stats(mspace msp);
+
+/*
+  mspace_trim behaves as malloc_trim, but
+  operates within the given space.
+*/
+DLMALLOC_EXPORT int mspace_trim(mspace msp, size_t pad);
+
+/*
+  An alias for mallopt.
+*/
+DLMALLOC_EXPORT int mspace_mallopt(int, int);
+
+#endif /* MSPACES */
+
+#ifdef __cplusplus
+}  /* end of extern "C" */
+#endif /* __cplusplus */
+
+/*
+  ========================================================================
+  To make a fully customizable malloc.h header file, cut everything
+  above this line, put into file malloc.h, edit to suit, and #include it
+  on the next line, as well as in programs that use this malloc.
+  ========================================================================
+*/
+
+/* #include "malloc.h" */
+
+/*------------------------------ internal #includes ---------------------- */
+
+#ifdef _MSC_VER
+#pragma warning( disable : 4146 ) /* no "unsigned" warnings */
+#endif /* _MSC_VER */
+#if !NO_MALLOC_STATS
+#include <stdio.h>       /* for printing in malloc_stats */
+#endif /* NO_MALLOC_STATS */
+#ifndef LACKS_ERRNO_H
+#include <errno.h>       /* for MALLOC_FAILURE_ACTION */
+#endif /* LACKS_ERRNO_H */
+#ifdef DEBUG
+#if ABORT_ON_ASSERT_FAILURE
+#undef assert
+#define assert(x) if(!(x)) ABORT
+#else /* ABORT_ON_ASSERT_FAILURE */
+#include <assert.h>
+#endif /* ABORT_ON_ASSERT_FAILURE */
+#else  /* DEBUG */
+#ifndef assert
+#define assert(x)
+#endif
+#define DEBUG 0
+#endif /* DEBUG */
+#if !defined(WIN32) && !defined(LACKS_TIME_H)
+#include <time.h>        /* for magic initialization */
+#endif /* WIN32 */
+#ifndef LACKS_STDLIB_H
+#include <stdlib.h>      /* for abort() */
+#endif /* LACKS_STDLIB_H */
+#ifndef LACKS_STRING_H
+#include <string.h>      /* for memset etc */
+#endif  /* LACKS_STRING_H */
+#if USE_BUILTIN_FFS
+#ifndef LACKS_STRINGS_H
+#include <strings.h>     /* for ffs */
+#endif /* LACKS_STRINGS_H */
+#endif /* USE_BUILTIN_FFS */
+#if HAVE_MMAP
+#ifndef LACKS_SYS_MMAN_H
+/* On some versions of linux, mremap decl in mman.h needs __USE_GNU set */
+#if (defined(linux) && !defined(__USE_GNU))
+#define __USE_GNU 1
+#include <sys/mman.h>    /* for mmap */
+#undef __USE_GNU
+#else
+#include <sys/mman.h>    /* for mmap */
+#endif /* linux */
+#endif /* LACKS_SYS_MMAN_H */
+#ifndef LACKS_FCNTL_H
+#include <fcntl.h>
+#endif /* LACKS_FCNTL_H */
+#endif /* HAVE_MMAP */
+#ifndef LACKS_UNISTD_H
+#include <unistd.h>     /* for sbrk, sysconf */
+#else /* LACKS_UNISTD_H */
+#if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__)
+extern void*     sbrk(ptrdiff_t);
+#endif /* FreeBSD etc */
+#endif /* LACKS_UNISTD_H */
+
+/* Declarations for locking */
+#if USE_LOCKS
+#ifndef WIN32
+#if defined (__SVR4) && defined (__sun)  /* solaris */
+#include <thread.h>
+#elif !defined(LACKS_SCHED_H)
+#include <sched.h>
+#endif /* solaris or LACKS_SCHED_H */
+#if (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0) || !USE_SPIN_LOCKS
+#include <pthread.h>
+#endif /* USE_RECURSIVE_LOCKS ... */
+#elif defined(_MSC_VER)
+#ifndef _M_AMD64
+/* These are already defined on AMD64 builds */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+LONG __cdecl _InterlockedCompareExchange(LONG volatile *Dest, LONG Exchange, LONG Comp);
+LONG __cdecl _InterlockedExchange(LONG volatile *Target, LONG Value);
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* _M_AMD64 */
+#pragma intrinsic (_InterlockedCompareExchange)
+#pragma intrinsic (_InterlockedExchange)
+#define interlockedcompareexchange _InterlockedCompareExchange
+#define interlockedexchange _InterlockedExchange
+#elif defined(WIN32) && defined(__GNUC__)
+#define interlockedcompareexchange(a, b, c) __sync_val_compare_and_swap(a, c, b)
+#define interlockedexchange __sync_lock_test_and_set
+#endif /* Win32 */
+#else /* USE_LOCKS */
+#endif /* USE_LOCKS */
+
+#ifndef LOCK_AT_FORK
+#define LOCK_AT_FORK 0
+#endif
+
+/* Declarations for bit scanning on win32 */
+#if defined(_MSC_VER) && _MSC_VER>=1300
+#ifndef BitScanForward /* Try to avoid pulling in WinNT.h */
+#ifdef __cplusplus
+extern "C" {
+#endif /* __cplusplus */
+unsigned char _BitScanForward(unsigned long *index, unsigned long mask);
+unsigned char _BitScanReverse(unsigned long *index, unsigned long mask);
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+
+#define BitScanForward _BitScanForward
+#define BitScanReverse _BitScanReverse
+#pragma intrinsic(_BitScanForward)
+#pragma intrinsic(_BitScanReverse)
+#endif /* BitScanForward */
+#endif /* defined(_MSC_VER) && _MSC_VER>=1300 */
+
+#ifndef WIN32
+#ifndef malloc_getpagesize
+#  ifdef _SC_PAGESIZE         /* some SVR4 systems omit an underscore */
+#    ifndef _SC_PAGE_SIZE
+#      define _SC_PAGE_SIZE _SC_PAGESIZE
+#    endif
+#  endif
+#  ifdef _SC_PAGE_SIZE
+#    define malloc_getpagesize sysconf(_SC_PAGE_SIZE)
+#  else
+#    if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE)
+       extern size_t getpagesize();
+#      define malloc_getpagesize getpagesize()
+#    else
+#      ifdef WIN32 /* use supplied emulation of getpagesize */
+#        define malloc_getpagesize getpagesize()
+#      else
+#        ifndef LACKS_SYS_PARAM_H
+#          include <sys/param.h>
+#        endif
+#        ifdef EXEC_PAGESIZE
+#          define malloc_getpagesize EXEC_PAGESIZE
+#        else
+#          ifdef NBPG
+#            ifndef CLSIZE
+#              define malloc_getpagesize NBPG
+#            else
+#              define malloc_getpagesize (NBPG * CLSIZE)
+#            endif
+#          else
+#            ifdef NBPC
+#              define malloc_getpagesize NBPC
+#            else
+#              ifdef PAGESIZE
+#                define malloc_getpagesize PAGESIZE
+#              else /* just guess */
+#                define malloc_getpagesize ((size_t)4096U)
+#              endif
+#            endif
+#          endif
+#        endif
+#      endif
+#    endif
+#  endif
+#endif
+#endif
+
+/* ------------------- size_t and alignment properties -------------------- */
+
+/* The byte and bit size of a size_t */
+#define SIZE_T_SIZE         (sizeof(size_t))
+#define SIZE_T_BITSIZE      (sizeof(size_t) << 3)
+
+/* Some constants coerced to size_t */
+/* Annoying but necessary to avoid errors on some platforms */
+#define SIZE_T_ZERO         ((size_t)0)
+#define SIZE_T_ONE          ((size_t)1)
+#define SIZE_T_TWO          ((size_t)2)
+#define SIZE_T_FOUR         ((size_t)4)
+#define TWO_SIZE_T_SIZES    (SIZE_T_SIZE<<1)
+#define FOUR_SIZE_T_SIZES   (SIZE_T_SIZE<<2)
+#define SIX_SIZE_T_SIZES    (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES)
+#define HALF_MAX_SIZE_T     (MAX_SIZE_T / 2U)
+
+/* The bit mask value corresponding to MALLOC_ALIGNMENT */
+#define CHUNK_ALIGN_MASK    (MALLOC_ALIGNMENT - SIZE_T_ONE)
+
+/* True if address a has acceptable alignment */
+#define is_aligned(A)       (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0)
+
+/* the number of bytes to offset an address to align it */
+#define align_offset(A)\
+ ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\
+  ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK))
+
+/* -------------------------- MMAP preliminaries ------------------------- */
+
+/*
+   If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and
+   checks to fail so compiler optimizer can delete code rather than
+   using so many "#if"s.
+*/
+
+
+/* MORECORE and MMAP must return MFAIL on failure */
+#define MFAIL                ((void*)(MAX_SIZE_T))
+#define CMFAIL               ((char*)(MFAIL)) /* defined for convenience */
+
+#if HAVE_MMAP
+
+#ifndef WIN32
+#define MUNMAP_DEFAULT(a, s)  munmap((a), (s))
+#define MMAP_PROT            (PROT_READ|PROT_WRITE)
+#if !defined(MAP_ANONYMOUS) && defined(MAP_ANON)
+#define MAP_ANONYMOUS        MAP_ANON
+#endif /* MAP_ANON */
+#ifdef MAP_ANONYMOUS
+#define MMAP_FLAGS           (MAP_PRIVATE|MAP_ANONYMOUS)
+#define MMAP_DEFAULT(s)       mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0)
+#else /* MAP_ANONYMOUS */
+/*
+   Nearly all versions of mmap support MAP_ANONYMOUS, so the following
+   is unlikely to be needed, but is supplied just in case.
+*/
+#define MMAP_FLAGS           (MAP_PRIVATE)
+static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */
+#define MMAP_DEFAULT(s) ((dev_zero_fd < 0) ? \
+           (dev_zero_fd = open("/dev/zero", O_RDWR), \
+            mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \
+            mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0))
+#endif /* MAP_ANONYMOUS */
+
+#define DIRECT_MMAP_DEFAULT(s) MMAP_DEFAULT(s)
+
+#else /* WIN32 */
+
+/* Win32 MMAP via VirtualAlloc */
+static FORCEINLINE void* win32mmap(size_t size) {
+  void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE);
+  return (ptr != 0)? ptr: MFAIL;
+}
+
+/* For direct MMAP, use MEM_TOP_DOWN to minimize interference */
+static FORCEINLINE void* win32direct_mmap(size_t size) {
+  void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN,
+                           PAGE_READWRITE);
+  return (ptr != 0)? ptr: MFAIL;
+}
+
+/* This function supports releasing coalesed segments */
+static FORCEINLINE int win32munmap(void* ptr, size_t size) {
+  MEMORY_BASIC_INFORMATION minfo;
+  char* cptr = (char*)ptr;
+  while (size) {
+    if (VirtualQuery(cptr, &minfo, sizeof(minfo)) == 0)
+      return -1;
+    if (minfo.BaseAddress != cptr || minfo.AllocationBase != cptr ||
+        minfo.State != MEM_COMMIT || minfo.RegionSize > size)
+      return -1;
+    if (VirtualFree(cptr, 0, MEM_RELEASE) == 0)
+      return -1;
+    cptr += minfo.RegionSize;
+    size -= minfo.RegionSize;
+  }
+  return 0;
+}
+
+#define MMAP_DEFAULT(s)             win32mmap(s)
+#define MUNMAP_DEFAULT(a, s)        win32munmap((a), (s))
+#define DIRECT_MMAP_DEFAULT(s)      win32direct_mmap(s)
+#endif /* WIN32 */
+#endif /* HAVE_MMAP */
+
+#if HAVE_MREMAP
+#ifndef WIN32
+#define MREMAP_DEFAULT(addr, osz, nsz, mv) mremap((addr), (osz), (nsz), (mv))
+#endif /* WIN32 */
+#endif /* HAVE_MREMAP */
+
+/**
+ * Define CALL_MORECORE
+ */
+#if HAVE_MORECORE
+    #ifdef MORECORE
+        #define CALL_MORECORE(S)    MORECORE(S)
+    #else  /* MORECORE */
+        #define CALL_MORECORE(S)    MORECORE_DEFAULT(S)
+    #endif /* MORECORE */
+#else  /* HAVE_MORECORE */
+    #define CALL_MORECORE(S)        MFAIL
+#endif /* HAVE_MORECORE */
+
+/**
+ * Define CALL_MMAP/CALL_MUNMAP/CALL_DIRECT_MMAP
+ */
+#if HAVE_MMAP
+    #define USE_MMAP_BIT            (SIZE_T_ONE)
+
+    #ifdef MMAP
+        #define CALL_MMAP(s)        MMAP(s)
+    #else /* MMAP */
+        #define CALL_MMAP(s)        MMAP_DEFAULT(s)
+    #endif /* MMAP */
+    #ifdef MUNMAP
+        #define CALL_MUNMAP(a, s)   MUNMAP((a), (s))
+    #else /* MUNMAP */
+        #define CALL_MUNMAP(a, s)   MUNMAP_DEFAULT((a), (s))
+    #endif /* MUNMAP */
+    #ifdef DIRECT_MMAP
+        #define CALL_DIRECT_MMAP(s) DIRECT_MMAP(s)
+    #else /* DIRECT_MMAP */
+        #define CALL_DIRECT_MMAP(s) DIRECT_MMAP_DEFAULT(s)
+    #endif /* DIRECT_MMAP */
+#else  /* HAVE_MMAP */
+    #define USE_MMAP_BIT            (SIZE_T_ZERO)
+
+    #define MMAP(s)                 MFAIL
+    #define MUNMAP(a, s)            (-1)
+    #define DIRECT_MMAP(s)          MFAIL
+    #define CALL_DIRECT_MMAP(s)     DIRECT_MMAP(s)
+    #define CALL_MMAP(s)            MMAP(s)
+    #define CALL_MUNMAP(a, s)       MUNMAP((a), (s))
+#endif /* HAVE_MMAP */
+
+/**
+ * Define CALL_MREMAP
+ */
+#if HAVE_MMAP && HAVE_MREMAP
+    #ifdef MREMAP
+        #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP((addr), (osz), (nsz), (mv))
+    #else /* MREMAP */
+        #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP_DEFAULT((addr), (osz), (nsz), (mv))
+    #endif /* MREMAP */
+#else  /* HAVE_MMAP && HAVE_MREMAP */
+    #define CALL_MREMAP(addr, osz, nsz, mv)     MFAIL
+#endif /* HAVE_MMAP && HAVE_MREMAP */
+
+/* mstate bit set if continguous morecore disabled or failed */
+#define USE_NONCONTIGUOUS_BIT (4U)
+
+/* segment bit set in create_mspace_with_base */
+#define EXTERN_BIT            (8U)
+
+
+/* --------------------------- Lock preliminaries ------------------------ */
+
+/*
+  When locks are defined, there is one global lock, plus
+  one per-mspace lock.
+
+  The global lock_ensures that mparams.magic and other unique
+  mparams values are initialized only once. It also protects
+  sequences of calls to MORECORE.  In many cases sys_alloc requires
+  two calls, that should not be interleaved with calls by other
+  threads.  This does not protect against direct calls to MORECORE
+  by other threads not using this lock, so there is still code to
+  cope the best we can on interference.
+
+  Per-mspace locks surround calls to malloc, free, etc.
+  By default, locks are simple non-reentrant mutexes.
+
+  Because lock-protected regions generally have bounded times, it is
+  OK to use the supplied simple spinlocks. Spinlocks are likely to
+  improve performance for lightly contended applications, but worsen
+  performance under heavy contention.
+
+  If USE_LOCKS is > 1, the definitions of lock routines here are
+  bypassed, in which case you will need to define the type MLOCK_T,
+  and at least INITIAL_LOCK, DESTROY_LOCK, ACQUIRE_LOCK, RELEASE_LOCK
+  and TRY_LOCK.  You must also declare a
+    static MLOCK_T malloc_global_mutex = { initialization values };.
+
+*/
+
+#if !USE_LOCKS
+#define USE_LOCK_BIT               (0U)
+#define INITIAL_LOCK(l)            (0)
+#define DESTROY_LOCK(l)            (0)
+#define ACQUIRE_MALLOC_GLOBAL_LOCK()
+#define RELEASE_MALLOC_GLOBAL_LOCK()
+
+#else
+#if USE_LOCKS > 1
+/* -----------------------  User-defined locks ------------------------ */
+/* Define your own lock implementation here */
+/* #define INITIAL_LOCK(lk)  ... */
+/* #define DESTROY_LOCK(lk)  ... */
+/* #define ACQUIRE_LOCK(lk)  ... */
+/* #define RELEASE_LOCK(lk)  ... */
+/* #define TRY_LOCK(lk) ... */
+/* static MLOCK_T malloc_global_mutex = ... */
+
+#elif USE_SPIN_LOCKS
+
+/* First, define CAS_LOCK and CLEAR_LOCK on ints */
+/* Note CAS_LOCK defined to return 0 on success */
+
+#if defined(__GNUC__)&& (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1))
+#define CAS_LOCK(sl)     __sync_lock_test_and_set(sl, 1)
+#define CLEAR_LOCK(sl)   __sync_lock_release(sl)
+
+#elif (defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)))
+/* Custom spin locks for older gcc on x86 */
+static FORCEINLINE int x86_cas_lock(int *sl) {
+  int ret;
+  int val = 1;
+  int cmp = 0;
+  __asm__ __volatile__  ("lock; cmpxchgl %1, %2"
+                         : "=a" (ret)
+                         : "r" (val), "m" (*(sl)), "0"(cmp)
+                         : "memory", "cc");
+  return ret;
+}
+
+static FORCEINLINE void x86_clear_lock(int* sl) {
+  assert(*sl != 0);
+  int prev = 0;
+  int ret;
+  __asm__ __volatile__ ("lock; xchgl %0, %1"
+                        : "=r" (ret)
+                        : "m" (*(sl)), "0"(prev)
+                        : "memory");
+}
+
+#define CAS_LOCK(sl)     x86_cas_lock(sl)
+#define CLEAR_LOCK(sl)   x86_clear_lock(sl)
+
+#else /* Win32 MSC */
+#define CAS_LOCK(sl)     interlockedexchange(sl, (LONG)1)
+#define CLEAR_LOCK(sl)   interlockedexchange (sl, (LONG)0)
+
+#endif /* ... gcc spins locks ... */
+
+/* How to yield for a spin lock */
+#define SPINS_PER_YIELD       63
+#if defined(_MSC_VER)
+#define SLEEP_EX_DURATION     50 /* delay for yield/sleep */
+#define SPIN_LOCK_YIELD  SleepEx(SLEEP_EX_DURATION, FALSE)
+#elif defined (__SVR4) && defined (__sun) /* solaris */
+#define SPIN_LOCK_YIELD   thr_yield();
+#elif !defined(LACKS_SCHED_H)
+#define SPIN_LOCK_YIELD   sched_yield();
+#else
+#define SPIN_LOCK_YIELD
+#endif /* ... yield ... */
+
+#if !defined(USE_RECURSIVE_LOCKS) || USE_RECURSIVE_LOCKS == 0
+/* Plain spin locks use single word (embedded in malloc_states) */
+static int spin_acquire_lock(int *sl) {
+  int spins = 0;
+  while (*(volatile int *)sl != 0 || CAS_LOCK(sl)) {
+    if ((++spins & SPINS_PER_YIELD) == 0) {
+      SPIN_LOCK_YIELD;
+    }
+  }
+  return 0;
+}
+
+#define MLOCK_T               int
+#define TRY_LOCK(sl)          !CAS_LOCK(sl)
+#define RELEASE_LOCK(sl)      CLEAR_LOCK(sl)
+#define ACQUIRE_LOCK(sl)      (CAS_LOCK(sl)? spin_acquire_lock(sl) : 0)
+#define INITIAL_LOCK(sl)      (*sl = 0)
+#define DESTROY_LOCK(sl)      (0)
+static MLOCK_T malloc_global_mutex = 0;
+
+#else /* USE_RECURSIVE_LOCKS */
+/* types for lock owners */
+#ifdef WIN32
+#define THREAD_ID_T           DWORD
+#define CURRENT_THREAD        GetCurrentThreadId()
+#define EQ_OWNER(X,Y)         ((X) == (Y))
+#else
+/*
+  Note: the following assume that pthread_t is a type that can be
+  initialized to (casted) zero. If this is not the case, you will need to
+  somehow redefine these or not use spin locks.
+*/
+#define THREAD_ID_T           pthread_t
+#define CURRENT_THREAD        pthread_self()
+#define EQ_OWNER(X,Y)         pthread_equal(X, Y)
+#endif
+
+struct malloc_recursive_lock {
+  int sl;
+  unsigned int c;
+  THREAD_ID_T threadid;
+};
+
+#define MLOCK_T  struct malloc_recursive_lock
+static MLOCK_T malloc_global_mutex = { 0, 0, (THREAD_ID_T)0};
+
+static FORCEINLINE void recursive_release_lock(MLOCK_T *lk) {
+  assert(lk->sl != 0);
+  if (--lk->c == 0) {
+    CLEAR_LOCK(&lk->sl);
+  }
+}
+
+static FORCEINLINE int recursive_acquire_lock(MLOCK_T *lk) {
+  THREAD_ID_T mythreadid = CURRENT_THREAD;
+  int spins = 0;
+  for (;;) {
+    if (*((volatile int *)(&lk->sl)) == 0) {
+      if (!CAS_LOCK(&lk->sl)) {
+        lk->threadid = mythreadid;
+        lk->c = 1;
+        return 0;
+      }
+    }
+    else if (EQ_OWNER(lk->threadid, mythreadid)) {
+      ++lk->c;
+      return 0;
+    }
+    if ((++spins & SPINS_PER_YIELD) == 0) {
+      SPIN_LOCK_YIELD;
+    }
+  }
+}
+
+static FORCEINLINE int recursive_try_lock(MLOCK_T *lk) {
+  THREAD_ID_T mythreadid = CURRENT_THREAD;
+  if (*((volatile int *)(&lk->sl)) == 0) {
+    if (!CAS_LOCK(&lk->sl)) {
+      lk->threadid = mythreadid;
+      lk->c = 1;
+      return 1;
+    }
+  }
+  else if (EQ_OWNER(lk->threadid, mythreadid)) {
+    ++lk->c;
+    return 1;
+  }
+  return 0;
+}
+
+#define RELEASE_LOCK(lk)      recursive_release_lock(lk)
+#define TRY_LOCK(lk)          recursive_try_lock(lk)
+#define ACQUIRE_LOCK(lk)      recursive_acquire_lock(lk)
+#define INITIAL_LOCK(lk)      ((lk)->threadid = (THREAD_ID_T)0, (lk)->sl = 0, (lk)->c = 0)
+#define DESTROY_LOCK(lk)      (0)
+#endif /* USE_RECURSIVE_LOCKS */
+
+#elif defined(WIN32) /* Win32 critical sections */
+#define MLOCK_T               CRITICAL_SECTION
+#define ACQUIRE_LOCK(lk)      (EnterCriticalSection(lk), 0)
+#define RELEASE_LOCK(lk)      LeaveCriticalSection(lk)
+#define TRY_LOCK(lk)          TryEnterCriticalSection(lk)
+#define INITIAL_LOCK(lk)      (!InitializeCriticalSectionAndSpinCount((lk), 0x80000000|4000))
+#define DESTROY_LOCK(lk)      (DeleteCriticalSection(lk), 0)
+#define NEED_GLOBAL_LOCK_INIT
+
+static MLOCK_T malloc_global_mutex;
+static volatile LONG malloc_global_mutex_status;
+
+/* Use spin loop to initialize global lock */
+static void init_malloc_global_mutex() {
+  for (;;) {
+    long stat = malloc_global_mutex_status;
+    if (stat > 0)
+      return;
+    /* transition to < 0 while initializing, then to > 0) */
+    if (stat == 0 &&
+        interlockedcompareexchange(&malloc_global_mutex_status, (LONG)-1, (LONG)0) == 0) {
+      InitializeCriticalSection(&malloc_global_mutex);
+      interlockedexchange(&malloc_global_mutex_status, (LONG)1);
+      return;
+    }
+    SleepEx(0, FALSE);
+  }
+}
+
+#else /* pthreads-based locks */
+#define MLOCK_T               pthread_mutex_t
+#define ACQUIRE_LOCK(lk)      pthread_mutex_lock(lk)
+#define RELEASE_LOCK(lk)      pthread_mutex_unlock(lk)
+#define TRY_LOCK(lk)          (!pthread_mutex_trylock(lk))
+#define INITIAL_LOCK(lk)      pthread_init_lock(lk)
+#define DESTROY_LOCK(lk)      pthread_mutex_destroy(lk)
+
+#if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0 && defined(linux) && !defined(PTHREAD_MUTEX_RECURSIVE)
+/* Cope with old-style linux recursive lock initialization by adding */
+/* skipped internal declaration from pthread.h */
+extern int pthread_mutexattr_setkind_np __P ((pthread_mutexattr_t *__attr,
+                                              int __kind));
+#define PTHREAD_MUTEX_RECURSIVE PTHREAD_MUTEX_RECURSIVE_NP
+#define pthread_mutexattr_settype(x,y) pthread_mutexattr_setkind_np(x,y)
+#endif /* USE_RECURSIVE_LOCKS ... */
+
+static MLOCK_T malloc_global_mutex = PTHREAD_MUTEX_INITIALIZER;
+
+static int pthread_init_lock (MLOCK_T *lk) {
+  pthread_mutexattr_t attr;
+  if (pthread_mutexattr_init(&attr)) return 1;
+#if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0
+  if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)) return 1;
+#endif
+  if (pthread_mutex_init(lk, &attr)) return 1;
+  if (pthread_mutexattr_destroy(&attr)) return 1;
+  return 0;
+}
+
+#endif /* ... lock types ... */
+
+/* Common code for all lock types */
+#define USE_LOCK_BIT               (2U)
+
+#ifndef ACQUIRE_MALLOC_GLOBAL_LOCK
+#define ACQUIRE_MALLOC_GLOBAL_LOCK()  ACQUIRE_LOCK(&malloc_global_mutex);
+#endif
+
+#ifndef RELEASE_MALLOC_GLOBAL_LOCK
+#define RELEASE_MALLOC_GLOBAL_LOCK()  RELEASE_LOCK(&malloc_global_mutex);
+#endif
+
+#endif /* USE_LOCKS */
+
+/* -----------------------  Chunk representations ------------------------ */
+
+/*
+  (The following includes lightly edited explanations by Colin Plumb.)
+
+  The malloc_chunk declaration below is misleading (but accurate and
+  necessary).  It declares a "view" into memory allowing access to
+  necessary fields at known offsets from a given base.
+
+  Chunks of memory are maintained using a `boundary tag' method as
+  originally described by Knuth.  (See the paper by Paul Wilson
+  ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such
+  techniques.)  Sizes of free chunks are stored both in the front of
+  each chunk and at the end.  This makes consolidating fragmented
+  chunks into bigger chunks fast.  The head fields also hold bits
+  representing whether chunks are free or in use.
+
+  Here are some pictures to make it clearer.  They are "exploded" to
+  show that the state of a chunk can be thought of as extending from
+  the high 31 bits of the head field of its header through the
+  prev_foot and PINUSE_BIT bit of the following chunk header.
+
+  A chunk that's in use looks like:
+
+   chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+           | Size of previous chunk (if P = 0)                             |
+           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
+         | Size of this chunk                                         1| +-+
+   mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         |                                                               |
+         +-                                                             -+
+         |                                                               |
+         +-                                                             -+
+         |                                                               :
+         +-      size - sizeof(size_t) available payload bytes          -+
+         :                                                               |
+ chunk-> +-                                                             -+
+         |                                                               |
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1|
+       | Size of next chunk (may or may not be in use)               | +-+
+ mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+    And if it's free, it looks like this:
+
+   chunk-> +-                                                             -+
+           | User payload (must be in use, or we would have merged!)       |
+           +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P|
+         | Size of this chunk                                         0| +-+
+   mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         | Next pointer                                                  |
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         | Prev pointer                                                  |
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         |                                                               :
+         +-      size - sizeof(struct chunk) unused bytes               -+
+         :                                                               |
+ chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+         | Size of this chunk                                            |
+         +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0|
+       | Size of next chunk (must be in use, or we would have merged)| +-+
+ mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+       |                                                               :
+       +- User payload                                                -+
+       :                                                               |
+       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+                                                                     |0|
+                                                                     +-+
+  Note that since we always merge adjacent free chunks, the chunks
+  adjacent to a free chunk must be in use.
+
+  Given a pointer to a chunk (which can be derived trivially from the
+  payload pointer) we can, in O(1) time, find out whether the adjacent
+  chunks are free, and if so, unlink them from the lists that they
+  are on and merge them with the current chunk.
+
+  Chunks always begin on even word boundaries, so the mem portion
+  (which is returned to the user) is also on an even word boundary, and
+  thus at least double-word aligned.
+
+  The P (PINUSE_BIT) bit, stored in the unused low-order bit of the
+  chunk size (which is always a multiple of two words), is an in-use
+  bit for the *previous* chunk.  If that bit is *clear*, then the
+  word before the current chunk size contains the previous chunk
+  size, and can be used to find the front of the previous chunk.
+  The very first chunk allocated always has this bit set, preventing
+  access to non-existent (or non-owned) memory. If pinuse is set for
+  any given chunk, then you CANNOT determine the size of the
+  previous chunk, and might even get a memory addressing fault when
+  trying to do so.
+
+  The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of
+  the chunk size redundantly records whether the current chunk is
+  inuse (unless the chunk is mmapped). This redundancy enables usage
+  checks within free and realloc, and reduces indirection when freeing
+  and consolidating chunks.
+
+  Each freshly allocated chunk must have both cinuse and pinuse set.
+  That is, each allocated chunk borders either a previously allocated
+  and still in-use chunk, or the base of its memory arena. This is
+  ensured by making all allocations from the `lowest' part of any
+  found chunk.  Further, no free chunk physically borders another one,
+  so each free chunk is known to be preceded and followed by either
+  inuse chunks or the ends of memory.
+
+  Note that the `foot' of the current chunk is actually represented
+  as the prev_foot of the NEXT chunk. This makes it easier to
+  deal with alignments etc but can be very confusing when trying
+  to extend or adapt this code.
+
+  The exceptions to all this are
+
+     1. The special chunk `top' is the top-most available chunk (i.e.,
+        the one bordering the end of available memory). It is treated
+        specially.  Top is never included in any bin, is used only if
+        no other chunk is available, and is released back to the
+        system if it is very large (see M_TRIM_THRESHOLD).  In effect,
+        the top chunk is treated as larger (and thus less well
+        fitting) than any other available chunk.  The top chunk
+        doesn't update its trailing size field since there is no next
+        contiguous chunk that would have to index off it. However,
+        space is still allocated for it (TOP_FOOT_SIZE) to enable
+        separation or merging when space is extended.
+
+     3. Chunks allocated via mmap, have both cinuse and pinuse bits
+        cleared in their head fields.  Because they are allocated
+        one-by-one, each must carry its own prev_foot field, which is
+        also used to hold the offset this chunk has within its mmapped
+        region, which is needed to preserve alignment. Each mmapped
+        chunk is trailed by the first two fields of a fake next-chunk
+        for sake of usage checks.
+
+*/
+
+struct malloc_chunk {
+  size_t               prev_foot;  /* Size of previous chunk (if free).  */
+  size_t               head;       /* Size and inuse bits. */
+  struct malloc_chunk* fd;         /* double links -- used only if free. */
+  struct malloc_chunk* bk;
+};
+
+typedef struct malloc_chunk  mchunk;
+typedef struct malloc_chunk* mchunkptr;
+typedef struct malloc_chunk* sbinptr;  /* The type of bins of chunks */
+typedef unsigned int bindex_t;         /* Described below */
+typedef unsigned int binmap_t;         /* Described below */
+typedef unsigned int flag_t;           /* The type of various bit flag sets */
+
+/* ------------------- Chunks sizes and alignments ----------------------- */
+
+#define MCHUNK_SIZE         (sizeof(mchunk))
+
+#if FOOTERS
+#define CHUNK_OVERHEAD      (TWO_SIZE_T_SIZES)
+#else /* FOOTERS */
+#define CHUNK_OVERHEAD      (SIZE_T_SIZE)
+#endif /* FOOTERS */
+
+/* MMapped chunks need a second word of overhead ... */
+#define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES)
+/* ... and additional padding for fake next-chunk at foot */
+#define MMAP_FOOT_PAD       (FOUR_SIZE_T_SIZES)
+
+/* The smallest size we can malloc is an aligned minimal chunk */
+#define MIN_CHUNK_SIZE\
+  ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
+
+/* conversion from malloc headers to user pointers, and back */
+#define chunk2mem(p)        ((void*)((char*)(p)       + TWO_SIZE_T_SIZES))
+#define mem2chunk(mem)      ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES))
+/* chunk associated with aligned address A */
+#define align_as_chunk(A)   (mchunkptr)((A) + align_offset(chunk2mem(A)))
+
+/* Bounds on request (not chunk) sizes. */
+#define MAX_REQUEST         ((-MIN_CHUNK_SIZE) << 2)
+#define MIN_REQUEST         (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE)
+
+/* pad request bytes into a usable size */
+#define pad_request(req) \
+   (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK)
+
+/* pad request, checking for minimum (but not maximum) */
+#define request2size(req) \
+  (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req))
+
+
+/* ------------------ Operations on head and foot fields ----------------- */
+
+/*
+  The head field of a chunk is or'ed with PINUSE_BIT when previous
+  adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in
+  use, unless mmapped, in which case both bits are cleared.
+
+  FLAG4_BIT is not used by this malloc, but might be useful in extensions.
+*/
+
+#define PINUSE_BIT          (SIZE_T_ONE)
+#define CINUSE_BIT          (SIZE_T_TWO)
+#define FLAG4_BIT           (SIZE_T_FOUR)
+#define INUSE_BITS          (PINUSE_BIT|CINUSE_BIT)
+#define FLAG_BITS           (PINUSE_BIT|CINUSE_BIT|FLAG4_BIT)
+
+/* Head value for fenceposts */
+#define FENCEPOST_HEAD      (INUSE_BITS|SIZE_T_SIZE)
+
+/* extraction of fields from head words */
+#define cinuse(p)           ((p)->head & CINUSE_BIT)
+#define pinuse(p)           ((p)->head & PINUSE_BIT)
+#define flag4inuse(p)       ((p)->head & FLAG4_BIT)
+#define is_inuse(p)         (((p)->head & INUSE_BITS) != PINUSE_BIT)
+#define is_mmapped(p)       (((p)->head & INUSE_BITS) == 0)
+
+#define chunksize(p)        ((p)->head & ~(FLAG_BITS))
+
+#define clear_pinuse(p)     ((p)->head &= ~PINUSE_BIT)
+#define set_flag4(p)        ((p)->head |= FLAG4_BIT)
+#define clear_flag4(p)      ((p)->head &= ~FLAG4_BIT)
+
+/* Treat space at ptr +/- offset as a chunk */
+#define chunk_plus_offset(p, s)  ((mchunkptr)(((char*)(p)) + (s)))
+#define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s)))
+
+/* Ptr to next or previous physical malloc_chunk. */
+#define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~FLAG_BITS)))
+#define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) ))
+
+/* extract next chunk's pinuse bit */
+#define next_pinuse(p)  ((next_chunk(p)->head) & PINUSE_BIT)
+
+/* Get/set size at footer */
+#define get_foot(p, s)  (((mchunkptr)((char*)(p) + (s)))->prev_foot)
+#define set_foot(p, s)  (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s))
+
+/* Set size, pinuse bit, and foot */
+#define set_size_and_pinuse_of_free_chunk(p, s)\
+  ((p)->head = (s|PINUSE_BIT), set_foot(p, s))
+
+/* Set size, pinuse bit, foot, and clear next pinuse */
+#define set_free_with_pinuse(p, s, n)\
+  (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s))
+
+/* Get the internal overhead associated with chunk p */
+#define overhead_for(p)\
+ (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD)
+
+/* Return true if malloced space is not necessarily cleared */
+#if MMAP_CLEARS
+#define calloc_must_clear(p) (!is_mmapped(p))
+#else /* MMAP_CLEARS */
+#define calloc_must_clear(p) (1)
+#endif /* MMAP_CLEARS */
+
+/* ---------------------- Overlaid data structures ----------------------- */
+
+/*
+  When chunks are not in use, they are treated as nodes of either
+  lists or trees.
+
+  "Small"  chunks are stored in circular doubly-linked lists, and look
+  like this:
+
+    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Size of previous chunk                            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    `head:' |             Size of chunk, in bytes                         |P|
+      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Forward pointer to next chunk in list             |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Back pointer to previous chunk in list            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Unused space (may be 0 bytes long)                .
+            .                                                               .
+            .                                                               |
+nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    `foot:' |             Size of chunk, in bytes                           |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+  Larger chunks are kept in a form of bitwise digital trees (aka
+  tries) keyed on chunksizes.  Because malloc_tree_chunks are only for
+  free chunks greater than 256 bytes, their size doesn't impose any
+  constraints on user chunk sizes.  Each node looks like:
+
+    chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Size of previous chunk                            |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    `head:' |             Size of chunk, in bytes                         |P|
+      mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Forward pointer to next chunk of same size        |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Back pointer to previous chunk of same size       |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Pointer to left child (child[0])                  |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Pointer to right child (child[1])                 |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Pointer to parent                                 |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             bin index of this chunk                           |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+            |             Unused space                                      .
+            .                                                               |
+nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+    `foot:' |             Size of chunk, in bytes                           |
+            +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+
+  Each tree holding treenodes is a tree of unique chunk sizes.  Chunks
+  of the same size are arranged in a circularly-linked list, with only
+  the oldest chunk (the next to be used, in our FIFO ordering)
+  actually in the tree.  (Tree members are distinguished by a non-null
+  parent pointer.)  If a chunk with the same size an an existing node
+  is inserted, it is linked off the existing node using pointers that
+  work in the same way as fd/bk pointers of small chunks.
+
+  Each tree contains a power of 2 sized range of chunk sizes (the
+  smallest is 0x100 <= x < 0x180), which is is divided in half at each
+  tree level, with the chunks in the smaller half of the range (0x100
+  <= x < 0x140 for the top nose) in the left subtree and the larger
+  half (0x140 <= x < 0x180) in the right subtree.  This is, of course,
+  done by inspecting individual bits.
+
+  Using these rules, each node's left subtree contains all smaller
+  sizes than its right subtree.  However, the node at the root of each
+  subtree has no particular ordering relationship to either.  (The
+  dividing line between the subtree sizes is based on trie relation.)
+  If we remove the last chunk of a given size from the interior of the
+  tree, we need to replace it with a leaf node.  The tree ordering
+  rules permit a node to be replaced by any leaf below it.
+
+  The smallest chunk in a tree (a common operation in a best-fit
+  allocator) can be found by walking a path to the leftmost leaf in
+  the tree.  Unlike a usual binary tree, where we follow left child
+  pointers until we reach a null, here we follow the right child
+  pointer any time the left one is null, until we reach a leaf with
+  both child pointers null. The smallest chunk in the tree will be
+  somewhere along that path.
+
+  The worst case number of steps to add, find, or remove a node is
+  bounded by the number of bits differentiating chunks within
+  bins. Under current bin calculations, this ranges from 6 up to 21
+  (for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case
+  is of course much better.
+*/
+
+struct malloc_tree_chunk {
+  /* The first four fields must be compatible with malloc_chunk */
+  size_t                    prev_foot;
+  size_t                    head;
+  struct malloc_tree_chunk* fd;
+  struct malloc_tree_chunk* bk;
+
+  struct malloc_tree_chunk* child[2];
+  struct malloc_tree_chunk* parent;
+  bindex_t                  index;
+};
+
+typedef struct malloc_tree_chunk  tchunk;
+typedef struct malloc_tree_chunk* tchunkptr;
+typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */
+
+/* A little helper macro for trees */
+#define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1])
+
+/* ----------------------------- Segments -------------------------------- */
+
+/*
+  Each malloc space may include non-contiguous segments, held in a
+  list headed by an embedded malloc_segment record representing the
+  top-most space. Segments also include flags holding properties of
+  the space. Large chunks that are directly allocated by mmap are not
+  included in this list. They are instead independently created and
+  destroyed without otherwise keeping track of them.
+
+  Segment management mainly comes into play for spaces allocated by
+  MMAP.  Any call to MMAP might or might not return memory that is
+  adjacent to an existing segment.  MORECORE normally contiguously
+  extends the current space, so this space is almost always adjacent,
+  which is simpler and faster to deal with. (This is why MORECORE is
+  used preferentially to MMAP when both are available -- see
+  sys_alloc.)  When allocating using MMAP, we don't use any of the
+  hinting mechanisms (inconsistently) supported in various
+  implementations of unix mmap, or distinguish reserving from
+  committing memory. Instead, we just ask for space, and exploit
+  contiguity when we get it.  It is probably possible to do
+  better than this on some systems, but no general scheme seems
+  to be significantly better.
+
+  Management entails a simpler variant of the consolidation scheme
+  used for chunks to reduce fragmentation -- new adjacent memory is
+  normally prepended or appended to an existing segment. However,
+  there are limitations compared to chunk consolidation that mostly
+  reflect the fact that segment processing is relatively infrequent
+  (occurring only when getting memory from system) and that we
+  don't expect to have huge numbers of segments:
+
+  * Segments are not indexed, so traversal requires linear scans.  (It
+    would be possible to index these, but is not worth the extra
+    overhead and complexity for most programs on most platforms.)
+  * New segments are only appended to old ones when holding top-most
+    memory; if they cannot be prepended to others, they are held in
+    different segments.
+
+  Except for the top-most segment of an mstate, each segment record
+  is kept at the tail of its segment. Segments are added by pushing
+  segment records onto the list headed by &mstate.seg for the
+  containing mstate.
+
+  Segment flags control allocation/merge/deallocation policies:
+  * If EXTERN_BIT set, then we did not allocate this segment,
+    and so should not try to deallocate or merge with others.
+    (This currently holds only for the initial segment passed
+    into create_mspace_with_base.)
+  * If USE_MMAP_BIT set, the segment may be merged with
+    other surrounding mmapped segments and trimmed/de-allocated
+    using munmap.
+  * If neither bit is set, then the segment was obtained using
+    MORECORE so can be merged with surrounding MORECORE'd segments
+    and deallocated/trimmed using MORECORE with negative arguments.
+*/
+
+struct malloc_segment {
+  char*        base;             /* base address */
+  size_t       size;             /* allocated size */
+  struct malloc_segment* next;   /* ptr to next segment */
+  flag_t       sflags;           /* mmap and extern flag */
+};
+
+#define is_mmapped_segment(S)  ((S)->sflags & USE_MMAP_BIT)
+#define is_extern_segment(S)   ((S)->sflags & EXTERN_BIT)
+
+typedef struct malloc_segment  msegment;
+typedef struct malloc_segment* msegmentptr;
+
+/* ---------------------------- malloc_state ----------------------------- */
+
+/*
+   A malloc_state holds all of the bookkeeping for a space.
+   The main fields are:
+
+  Top
+    The topmost chunk of the currently active segment. Its size is
+    cached in topsize.  The actual size of topmost space is
+    topsize+TOP_FOOT_SIZE, which includes space reserved for adding
+    fenceposts and segment records if necessary when getting more
+    space from the system.  The size at which to autotrim top is
+    cached from mparams in trim_check, except that it is disabled if
+    an autotrim fails.
+
+  Designated victim (dv)
+    This is the preferred chunk for servicing small requests that
+    don't have exact fits.  It is normally the chunk split off most
+    recently to service another small request.  Its size is cached in
+    dvsize. The link fields of this chunk are not maintained since it
+    is not kept in a bin.
+
+  SmallBins
+    An array of bin headers for free chunks.  These bins hold chunks
+    with sizes less than MIN_LARGE_SIZE bytes. Each bin contains
+    chunks of all the same size, spaced 8 bytes apart.  To simplify
+    use in double-linked lists, each bin header acts as a malloc_chunk
+    pointing to the real first node, if it exists (else pointing to
+    itself).  This avoids special-casing for headers.  But to avoid
+    waste, we allocate only the fd/bk pointers of bins, and then use
+    repositioning tricks to treat these as the fields of a chunk.
+
+  TreeBins
+    Treebins are pointers to the roots of trees holding a range of
+    sizes. There are 2 equally spaced treebins for each power of two
+    from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything
+    larger.
+
+  Bin maps
+    There is one bit map for small bins ("smallmap") and one for
+    treebins ("treemap).  Each bin sets its bit when non-empty, and
+    clears the bit when empty.  Bit operations are then used to avoid
+    bin-by-bin searching -- nearly all "search" is done without ever
+    looking at bins that won't be selected.  The bit maps
+    conservatively use 32 bits per map word, even if on 64bit system.
+    For a good description of some of the bit-based techniques used
+    here, see Henry S. Warren Jr's book "Hacker's Delight" (and
+    supplement at http://hackersdelight.org/). Many of these are
+    intended to reduce the branchiness of paths through malloc etc, as
+    well as to reduce the number of memory locations read or written.
+
+  Segments
+    A list of segments headed by an embedded malloc_segment record
+    representing the initial space.
+
+  Address check support
+    The least_addr field is the least address ever obtained from
+    MORECORE or MMAP. Attempted frees and reallocs of any address less
+    than this are trapped (unless INSECURE is defined).
+
+  Magic tag
+    A cross-check field that should always hold same value as mparams.magic.
+
+  Max allowed footprint
+    The maximum allowed bytes to allocate from system (zero means no limit)
+
+  Flags
+    Bits recording whether to use MMAP, locks, or contiguous MORECORE
+
+  Statistics
+    Each space keeps track of current and maximum system memory
+    obtained via MORECORE or MMAP.
+
+  Trim support
+    Fields holding the amount of unused topmost memory that should trigger
+    trimming, and a counter to force periodic scanning to release unused
+    non-topmost segments.
+
+  Locking
+    If USE_LOCKS is defined, the "mutex" lock is acquired and released
+    around every public call using this mspace.
+
+  Extension support
+    A void* pointer and a size_t field that can be used to help implement
+    extensions to this malloc.
+*/
+
+/* Bin types, widths and sizes */
+#define NSMALLBINS        (32U)
+#define NTREEBINS         (32U)
+#define SMALLBIN_SHIFT    (3U)
+#define SMALLBIN_WIDTH    (SIZE_T_ONE << SMALLBIN_SHIFT)
+#define TREEBIN_SHIFT     (8U)
+#define MIN_LARGE_SIZE    (SIZE_T_ONE << TREEBIN_SHIFT)
+#define MAX_SMALL_SIZE    (MIN_LARGE_SIZE - SIZE_T_ONE)
+#define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD)
+
+struct malloc_state {
+  binmap_t   smallmap;
+  binmap_t   treemap;
+  size_t     dvsize;
+  size_t     topsize;
+  char*      least_addr;
+  mchunkptr  dv;
+  mchunkptr  top;
+  size_t     trim_check;
+  size_t     release_checks;
+  size_t     magic;
+  mchunkptr  smallbins[(NSMALLBINS+1)*2];
+  tbinptr    treebins[NTREEBINS];
+  size_t     footprint;
+  size_t     max_footprint;
+  size_t     footprint_limit; /* zero means no limit */
+  flag_t     mflags;
+#if USE_LOCKS
+  MLOCK_T    mutex;     /* locate lock among fields that rarely change */
+#endif /* USE_LOCKS */
+  msegment   seg;
+  void*      extp;      /* Unused but available for extensions */
+  size_t     exts;
+};
+
+typedef struct malloc_state*    mstate;
+
+/* ------------- Global malloc_state and malloc_params ------------------- */
+
+/*
+  malloc_params holds global properties, including those that can be
+  dynamically set using mallopt. There is a single instance, mparams,
+  initialized in init_mparams. Note that the non-zeroness of "magic"
+  also serves as an initialization flag.
+*/
+
+struct malloc_params {
+  size_t magic;
+  size_t page_size;
+  size_t granularity;
+  size_t mmap_threshold;
+  size_t trim_threshold;
+  flag_t default_mflags;
+};
+
+static struct malloc_params mparams;
+
+/* Ensure mparams initialized */
+#define ensure_initialization() (void)(mparams.magic != 0 || init_mparams())
+
+#if !ONLY_MSPACES
+
+/* The global malloc_state used for all non-"mspace" calls */
+static struct malloc_state _gm_;
+#define gm                 (&_gm_)
+#define is_global(M)       ((M) == &_gm_)
+
+#endif /* !ONLY_MSPACES */
+
+#define is_initialized(M)  ((M)->top != 0)
+
+/* -------------------------- system alloc setup ------------------------- */
+
+/* Operations on mflags */
+
+#define use_lock(M)           ((M)->mflags &   USE_LOCK_BIT)
+#define enable_lock(M)        ((M)->mflags |=  USE_LOCK_BIT)
+#if USE_LOCKS
+#define disable_lock(M)       ((M)->mflags &= ~USE_LOCK_BIT)
+#else
+#define disable_lock(M)
+#endif
+
+#define use_mmap(M)           ((M)->mflags &   USE_MMAP_BIT)
+#define enable_mmap(M)        ((M)->mflags |=  USE_MMAP_BIT)
+#if HAVE_MMAP
+#define disable_mmap(M)       ((M)->mflags &= ~USE_MMAP_BIT)
+#else
+#define disable_mmap(M)
+#endif
+
+#define use_noncontiguous(M)  ((M)->mflags &   USE_NONCONTIGUOUS_BIT)
+#define disable_contiguous(M) ((M)->mflags |=  USE_NONCONTIGUOUS_BIT)
+
+#define set_lock(M,L)\
+ ((M)->mflags = (L)?\
+  ((M)->mflags | USE_LOCK_BIT) :\
+  ((M)->mflags & ~USE_LOCK_BIT))
+
+/* page-align a size */
+#define page_align(S)\
+ (((S) + (mparams.page_size - SIZE_T_ONE)) & ~(mparams.page_size - SIZE_T_ONE))
+
+/* granularity-align a size */
+#define granularity_align(S)\
+  (((S) + (mparams.granularity - SIZE_T_ONE))\
+   & ~(mparams.granularity - SIZE_T_ONE))
+
+
+/* For mmap, use granularity alignment on windows, else page-align */
+#ifdef WIN32
+#define mmap_align(S) granularity_align(S)
+#else
+#define mmap_align(S) page_align(S)
+#endif
+
+/* For sys_alloc, enough padding to ensure can malloc request on success */
+#define SYS_ALLOC_PADDING (TOP_FOOT_SIZE + MALLOC_ALIGNMENT)
+
+#define is_page_aligned(S)\
+   (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0)
+#define is_granularity_aligned(S)\
+   (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0)
+
+/*  True if segment S holds address A */
+#define segment_holds(S, A)\
+  ((char*)(A) >= S->base && (char*)(A) < S->base + S->size)
+
+/* Return segment holding given address */
+static msegmentptr segment_holding(mstate m, char* addr) {
+  msegmentptr sp = &m->seg;
+  for (;;) {
+    if (addr >= sp->base && addr < sp->base + sp->size)
+      return sp;
+    if ((sp = sp->next) == 0)
+      return 0;
+  }
+}
+
+/* Return true if segment contains a segment link */
+static int has_segment_link(mstate m, msegmentptr ss) {
+  msegmentptr sp = &m->seg;
+  for (;;) {
+    if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size)
+      return 1;
+    if ((sp = sp->next) == 0)
+      return 0;
+  }
+}
+
+#ifndef MORECORE_CANNOT_TRIM
+#define should_trim(M,s)  ((s) > (M)->trim_check)
+#else  /* MORECORE_CANNOT_TRIM */
+#define should_trim(M,s)  (0)
+#endif /* MORECORE_CANNOT_TRIM */
+
+/*
+  TOP_FOOT_SIZE is padding at the end of a segment, including space
+  that may be needed to place segment records and fenceposts when new
+  noncontiguous segments are added.
+*/
+#define TOP_FOOT_SIZE\
+  (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE)
+
+
+/* -------------------------------  Hooks -------------------------------- */
+
+/*
+  PREACTION should be defined to return 0 on success, and nonzero on
+  failure. If you are not using locking, you can redefine these to do
+  anything you like.
+*/
+
+#if USE_LOCKS
+#define PREACTION(M)  ((use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0)
+#define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); }
+#else /* USE_LOCKS */
+
+#ifndef PREACTION
+#define PREACTION(M) (0)
+#endif  /* PREACTION */
+
+#ifndef POSTACTION
+#define POSTACTION(M)
+#endif  /* POSTACTION */
+
+#endif /* USE_LOCKS */
+
+/*
+  CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses.
+  USAGE_ERROR_ACTION is triggered on detected bad frees and
+  reallocs. The argument p is an address that might have triggered the
+  fault. It is ignored by the two predefined actions, but might be
+  useful in custom actions that try to help diagnose errors.
+*/
+
+#if PROCEED_ON_ERROR
+
+/* A count of the number of corruption errors causing resets */
+int malloc_corruption_error_count;
+
+/* default corruption action */
+static void reset_on_error(mstate m);
+
+#define CORRUPTION_ERROR_ACTION(m)  reset_on_error(m)
+#define USAGE_ERROR_ACTION(m, p)
+
+#else /* PROCEED_ON_ERROR */
+
+#ifndef CORRUPTION_ERROR_ACTION
+#define CORRUPTION_ERROR_ACTION(m) ABORT
+#endif /* CORRUPTION_ERROR_ACTION */
+
+#ifndef USAGE_ERROR_ACTION
+#define USAGE_ERROR_ACTION(m,p) ABORT
+#endif /* USAGE_ERROR_ACTION */
+
+#endif /* PROCEED_ON_ERROR */
+
+
+/* -------------------------- Debugging setup ---------------------------- */
+
+#if ! DEBUG
+
+#define check_free_chunk(M,P)
+#define check_inuse_chunk(M,P)
+#define check_malloced_chunk(M,P,N)
+#define check_mmapped_chunk(M,P)
+#define check_malloc_state(M)
+#define check_top_chunk(M,P)
+
+#else /* DEBUG */
+#define check_free_chunk(M,P)       do_check_free_chunk(M,P)
+#define check_inuse_chunk(M,P)      do_check_inuse_chunk(M,P)
+#define check_top_chunk(M,P)        do_check_top_chunk(M,P)
+#define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N)
+#define check_mmapped_chunk(M,P)    do_check_mmapped_chunk(M,P)
+#define check_malloc_state(M)       do_check_malloc_state(M)
+
+static void   do_check_any_chunk(mstate m, mchunkptr p);
+static void   do_check_top_chunk(mstate m, mchunkptr p);
+static void   do_check_mmapped_chunk(mstate m, mchunkptr p);
+static void   do_check_inuse_chunk(mstate m, mchunkptr p);
+static void   do_check_free_chunk(mstate m, mchunkptr p);
+static void   do_check_malloced_chunk(mstate m, void* mem, size_t s);
+static void   do_check_tree(mstate m, tchunkptr t);
+static void   do_check_treebin(mstate m, bindex_t i);
+static void   do_check_smallbin(mstate m, bindex_t i);
+static void   do_check_malloc_state(mstate m);
+static int    bin_find(mstate m, mchunkptr x);
+static size_t traverse_and_check(mstate m);
+#endif /* DEBUG */
+
+/* ---------------------------- Indexing Bins ---------------------------- */
+
+#define is_small(s)         (((s) >> SMALLBIN_SHIFT) < NSMALLBINS)
+#define small_index(s)      (bindex_t)((s)  >> SMALLBIN_SHIFT)
+#define small_index2size(i) ((i)  << SMALLBIN_SHIFT)
+#define MIN_SMALL_INDEX     (small_index(MIN_CHUNK_SIZE))
+
+/* addressing by index. See above about smallbin repositioning */
+#define smallbin_at(M, i)   ((sbinptr)((char*)&((M)->smallbins[(i)<<1])))
+#define treebin_at(M,i)     (&((M)->treebins[i]))
+
+/* assign tree index for size S to variable I. Use x86 asm if possible  */
+#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+#define compute_tree_index(S, I)\
+{\
+  unsigned int X = S >> TREEBIN_SHIFT;\
+  if (X == 0)\
+    I = 0;\
+  else if (X > 0xFFFF)\
+    I = NTREEBINS-1;\
+  else {\
+    unsigned int K = (unsigned) sizeof(X)*__CHAR_BIT__ - 1 - (unsigned) __builtin_clz(X); \
+    I =  (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
+  }\
+}
+
+#elif defined (__INTEL_COMPILER)
+#define compute_tree_index(S, I)\
+{\
+  size_t X = S >> TREEBIN_SHIFT;\
+  if (X == 0)\
+    I = 0;\
+  else if (X > 0xFFFF)\
+    I = NTREEBINS-1;\
+  else {\
+    unsigned int K = _bit_scan_reverse (X); \
+    I =  (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
+  }\
+}
+
+#elif defined(_MSC_VER) && _MSC_VER>=1300
+#define compute_tree_index(S, I)\
+{\
+  size_t X = S >> TREEBIN_SHIFT;\
+  if (X == 0)\
+    I = 0;\
+  else if (X > 0xFFFF)\
+    I = NTREEBINS-1;\
+  else {\
+    unsigned int K;\
+    _BitScanReverse((DWORD *) &K, (DWORD) X);\
+    I =  (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\
+  }\
+}
+
+#else /* GNUC */
+#define compute_tree_index(S, I)\
+{\
+  size_t X = S >> TREEBIN_SHIFT;\
+  if (X == 0)\
+    I = 0;\
+  else if (X > 0xFFFF)\
+    I = NTREEBINS-1;\
+  else {\
+    unsigned int Y = (unsigned int)X;\
+    unsigned int N = ((Y - 0x100) >> 16) & 8;\
+    unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\
+    N += K;\
+    N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\
+    K = 14 - N + ((Y <<= K) >> 15);\
+    I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\
+  }\
+}
+#endif /* GNUC */
+
+/* Bit representing maximum resolved size in a treebin at i */
+#define bit_for_tree_index(i) \
+   (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2)
+
+/* Shift placing maximum resolved bit in a treebin at i as sign bit */
+#define leftshift_for_tree_index(i) \
+   ((i == NTREEBINS-1)? 0 : \
+    ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2)))
+
+/* The size of the smallest chunk held in bin with index i */
+#define minsize_for_tree_index(i) \
+   ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) |  \
+   (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1)))
+
+
+/* ------------------------ Operations on bin maps ----------------------- */
+
+/* bit corresponding to given index */
+#define idx2bit(i)              ((binmap_t)(1) << (i))
+
+/* Mark/Clear bits with given index */
+#define mark_smallmap(M,i)      ((M)->smallmap |=  idx2bit(i))
+#define clear_smallmap(M,i)     ((M)->smallmap &= ~idx2bit(i))
+#define smallmap_is_marked(M,i) ((M)->smallmap &   idx2bit(i))
+
+#define mark_treemap(M,i)       ((M)->treemap  |=  idx2bit(i))
+#define clear_treemap(M,i)      ((M)->treemap  &= ~idx2bit(i))
+#define treemap_is_marked(M,i)  ((M)->treemap  &   idx2bit(i))
+
+/* isolate the least set bit of a bitmap */
+#define least_bit(x)         ((x) & -(x))
+
+/* mask with all bits to left of least bit of x on */
+#define left_bits(x)         ((x<<1) | -(x<<1))
+
+/* mask with all bits to left of or equal to least bit of x on */
+#define same_or_left_bits(x) ((x) | -(x))
+
+/* index corresponding to given bit. Use x86 asm if possible */
+
+#if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))
+#define compute_bit2idx(X, I)\
+{\
+  unsigned int J;\
+  J = __builtin_ctz(X); \
+  I = (bindex_t)J;\
+}
+
+#elif defined (__INTEL_COMPILER)
+#define compute_bit2idx(X, I)\
+{\
+  unsigned int J;\
+  J = _bit_scan_forward (X); \
+  I = (bindex_t)J;\
+}
+
+#elif defined(_MSC_VER) && _MSC_VER>=1300
+#define compute_bit2idx(X, I)\
+{\
+  unsigned int J;\
+  _BitScanForward((DWORD *) &J, X);\
+  I = (bindex_t)J;\
+}
+
+#elif USE_BUILTIN_FFS
+#define compute_bit2idx(X, I) I = ffs(X)-1
+
+#else
+#define compute_bit2idx(X, I)\
+{\
+  unsigned int Y = X - 1;\
+  unsigned int K = Y >> (16-4) & 16;\
+  unsigned int N = K;        Y >>= K;\
+  N += K = Y >> (8-3) &  8;  Y >>= K;\
+  N += K = Y >> (4-2) &  4;  Y >>= K;\
+  N += K = Y >> (2-1) &  2;  Y >>= K;\
+  N += K = Y >> (1-0) &  1;  Y >>= K;\
+  I = (bindex_t)(N + Y);\
+}
+#endif /* GNUC */
+
+
+/* ----------------------- Runtime Check Support ------------------------- */
+
+/*
+  For security, the main invariant is that malloc/free/etc never
+  writes to a static address other than malloc_state, unless static
+  malloc_state itself has been corrupted, which cannot occur via
+  malloc (because of these checks). In essence this means that we
+  believe all pointers, sizes, maps etc held in malloc_state, but
+  check all of those linked or offsetted from other embedded data
+  structures.  These checks are interspersed with main code in a way
+  that tends to minimize their run-time cost.
+
+  When FOOTERS is defined, in addition to range checking, we also
+  verify footer fields of inuse chunks, which can be used guarantee
+  that the mstate controlling malloc/free is intact.  This is a
+  streamlined version of the approach described by William Robertson
+  et al in "Run-time Detection of Heap-based Overflows" LISA'03
+  http://www.usenix.org/events/lisa03/tech/robertson.html The footer
+  of an inuse chunk holds the xor of its mstate and a random seed,
+  that is checked upon calls to free() and realloc().  This is
+  (probabalistically) unguessable from outside the program, but can be
+  computed by any code successfully malloc'ing any chunk, so does not
+  itself provide protection against code that has already broken
+  security through some other means.  Unlike Robertson et al, we
+  always dynamically check addresses of all offset chunks (previous,
+  next, etc). This turns out to be cheaper than relying on hashes.
+*/
+
+#if !INSECURE
+/* Check if address a is at least as high as any from MORECORE or MMAP */
+#define ok_address(M, a) ((char*)(a) >= (M)->least_addr)
+/* Check if address of next chunk n is higher than base chunk p */
+#define ok_next(p, n)    ((char*)(p) < (char*)(n))
+/* Check if p has inuse status */
+#define ok_inuse(p)     is_inuse(p)
+/* Check if p has its pinuse bit on */
+#define ok_pinuse(p)     pinuse(p)
+
+#else /* !INSECURE */
+#define ok_address(M, a) (1)
+#define ok_next(b, n)    (1)
+#define ok_inuse(p)      (1)
+#define ok_pinuse(p)     (1)
+#endif /* !INSECURE */
+
+#if (FOOTERS && !INSECURE)
+/* Check if (alleged) mstate m has expected magic field */
+#define ok_magic(M)      ((M)->magic == mparams.magic)
+#else  /* (FOOTERS && !INSECURE) */
+#define ok_magic(M)      (1)
+#endif /* (FOOTERS && !INSECURE) */
+
+/* In gcc, use __builtin_expect to minimize impact of checks */
+#if !INSECURE
+#if defined(__GNUC__) && __GNUC__ >= 3
+#define RTCHECK(e)  __builtin_expect(e, 1)
+#else /* GNUC */
+#define RTCHECK(e)  (e)
+#endif /* GNUC */
+#else /* !INSECURE */
+#define RTCHECK(e)  (1)
+#endif /* !INSECURE */
+
+/* macros to set up inuse chunks with or without footers */
+
+#if !FOOTERS
+
+#define mark_inuse_foot(M,p,s)
+
+/* Macros for setting head/foot of non-mmapped chunks */
+
+/* Set cinuse bit and pinuse bit of next chunk */
+#define set_inuse(M,p,s)\
+  ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
+  ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
+
+/* Set cinuse and pinuse of this chunk and pinuse of next chunk */
+#define set_inuse_and_pinuse(M,p,s)\
+  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
+  ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT)
+
+/* Set size, cinuse and pinuse bit of this chunk */
+#define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
+  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT))
+
+#else /* FOOTERS */
+
+/* Set foot of inuse chunk to be xor of mstate and seed */
+#define mark_inuse_foot(M,p,s)\
+  (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic))
+
+#define get_mstate_for(p)\
+  ((mstate)(((mchunkptr)((char*)(p) +\
+    (chunksize(p))))->prev_foot ^ mparams.magic))
+
+#define set_inuse(M,p,s)\
+  ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\
+  (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \
+  mark_inuse_foot(M,p,s))
+
+#define set_inuse_and_pinuse(M,p,s)\
+  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
+  (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\
+ mark_inuse_foot(M,p,s))
+
+#define set_size_and_pinuse_of_inuse_chunk(M, p, s)\
+  ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\
+  mark_inuse_foot(M, p, s))
+
+#endif /* !FOOTERS */
+
+/* ---------------------------- setting mparams -------------------------- */
+
+#if LOCK_AT_FORK
+static void pre_fork(void)         { ACQUIRE_LOCK(&(gm)->mutex); }
+static void post_fork_parent(void) { RELEASE_LOCK(&(gm)->mutex); }
+static void post_fork_child(void)  { INITIAL_LOCK(&(gm)->mutex); }
+#endif /* LOCK_AT_FORK */
+
+/* Initialize mparams */
+static int init_mparams(void) {
+#ifdef NEED_GLOBAL_LOCK_INIT
+  if (malloc_global_mutex_status <= 0)
+    init_malloc_global_mutex();
+#endif
+
+  ACQUIRE_MALLOC_GLOBAL_LOCK();
+  if (mparams.magic == 0) {
+    size_t magic;
+    size_t psize;
+    size_t gsize;
+
+#ifndef WIN32
+    psize = malloc_getpagesize;
+    gsize = ((DEFAULT_GRANULARITY != 0)? DEFAULT_GRANULARITY : psize);
+#else /* WIN32 */
+    {
+      SYSTEM_INFO system_info;
+      GetSystemInfo(&system_info);
+      psize = system_info.dwPageSize;
+      gsize = ((DEFAULT_GRANULARITY != 0)?
+               DEFAULT_GRANULARITY : system_info.dwAllocationGranularity);
+    }
+#endif /* WIN32 */
+
+    /* Sanity-check configuration:
+       size_t must be unsigned and as wide as pointer type.
+       ints must be at least 4 bytes.
+       alignment must be at least 8.
+       Alignment, min chunk size, and page size must all be powers of 2.
+    */
+    if ((sizeof(size_t) != sizeof(char*)) ||
+        (MAX_SIZE_T < MIN_CHUNK_SIZE)  ||
+        (sizeof(int) < 4)  ||
+        (MALLOC_ALIGNMENT < (size_t)8U) ||
+        ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-SIZE_T_ONE)) != 0) ||
+        ((MCHUNK_SIZE      & (MCHUNK_SIZE-SIZE_T_ONE))      != 0) ||
+        ((gsize            & (gsize-SIZE_T_ONE))            != 0) ||
+        ((psize            & (psize-SIZE_T_ONE))            != 0))
+      ABORT;
+    mparams.granularity = gsize;
+    mparams.page_size = psize;
+    mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD;
+    mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD;
+#if MORECORE_CONTIGUOUS
+    mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT;
+#else  /* MORECORE_CONTIGUOUS */
+    mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT;
+#endif /* MORECORE_CONTIGUOUS */
+
+#if !ONLY_MSPACES
+    /* Set up lock for main malloc area */
+    gm->mflags = mparams.default_mflags;
+    (void)INITIAL_LOCK(&gm->mutex);
+#endif
+#if LOCK_AT_FORK
+    pthread_atfork(&pre_fork, &post_fork_parent, &post_fork_child);
+#endif
+
+    {
+#if USE_DEV_RANDOM
+      int fd;
+      unsigned char buf[sizeof(size_t)];
+      /* Try to use /dev/urandom, else fall back on using time */
+      if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 &&
+          read(fd, buf, sizeof(buf)) == sizeof(buf)) {
+        magic = *((size_t *) buf);
+        close(fd);
+      }
+      else
+#endif /* USE_DEV_RANDOM */
+#ifdef WIN32
+      magic = (size_t)(GetTickCount() ^ (size_t)0x55555555U);
+#elif defined(LACKS_TIME_H)
+      magic = (size_t)&magic ^ (size_t)0x55555555U;
+#else
+      magic = (size_t)(time(0) ^ (size_t)0x55555555U);
+#endif
+      magic |= (size_t)8U;    /* ensure nonzero */
+      magic &= ~(size_t)7U;   /* improve chances of fault for bad values */
+      /* Until memory modes commonly available, use volatile-write */
+      (*(volatile size_t *)(&(mparams.magic))) = magic;
+    }
+  }
+
+  RELEASE_MALLOC_GLOBAL_LOCK();
+  return 1;
+}
+
+/* support for mallopt */
+static int change_mparam(int param_number, int value) {
+  size_t val;
+  ensure_initialization();
+  val = (value == -1)? MAX_SIZE_T : (size_t)value;
+  switch(param_number) {
+  case M_TRIM_THRESHOLD:
+    mparams.trim_threshold = val;
+    return 1;
+  case M_GRANULARITY:
+    if (val >= mparams.page_size && ((val & (val-1)) == 0)) {
+      mparams.granularity = val;
+      return 1;
+    }
+    else
+      return 0;
+  case M_MMAP_THRESHOLD:
+    mparams.mmap_threshold = val;
+    return 1;
+  default:
+    return 0;
+  }
+}
+
+#if DEBUG
+/* ------------------------- Debugging Support --------------------------- */
+
+/* Check properties of any chunk, whether free, inuse, mmapped etc  */
+static void do_check_any_chunk(mstate m, mchunkptr p) {
+  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
+  assert(ok_address(m, p));
+}
+
+/* Check properties of top chunk */
+static void do_check_top_chunk(mstate m, mchunkptr p) {
+  msegmentptr sp = segment_holding(m, (char*)p);
+  size_t  sz = p->head & ~INUSE_BITS; /* third-lowest bit can be set! */
+  assert(sp != 0);
+  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
+  assert(ok_address(m, p));
+  assert(sz == m->topsize);
+  assert(sz > 0);
+  assert(sz == ((sp->base + sp->size) - (char*)p) - TOP_FOOT_SIZE);
+  assert(pinuse(p));
+  assert(!pinuse(chunk_plus_offset(p, sz)));
+}
+
+/* Check properties of (inuse) mmapped chunks */
+static void do_check_mmapped_chunk(mstate m, mchunkptr p) {
+  size_t  sz = chunksize(p);
+  size_t len = (sz + (p->prev_foot) + MMAP_FOOT_PAD);
+  assert(is_mmapped(p));
+  assert(use_mmap(m));
+  assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD));
+  assert(ok_address(m, p));
+  assert(!is_small(sz));
+  assert((len & (mparams.page_size-SIZE_T_ONE)) == 0);
+  assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD);
+  assert(chunk_plus_offset(p, sz+SIZE_T_SIZE)->head == 0);
+}
+
+/* Check properties of inuse chunks */
+static void do_check_inuse_chunk(mstate m, mchunkptr p) {
+  do_check_any_chunk(m, p);
+  assert(is_inuse(p));
+  assert(next_pinuse(p));
+  /* If not pinuse and not mmapped, previous chunk has OK offset */
+  assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p);
+  if (is_mmapped(p))
+    do_check_mmapped_chunk(m, p);
+}
+
+/* Check properties of free chunks */
+static void do_check_free_chunk(mstate m, mchunkptr p) {
+  size_t sz = chunksize(p);
+  mchunkptr next = chunk_plus_offset(p, sz);
+  do_check_any_chunk(m, p);
+  assert(!is_inuse(p));
+  assert(!next_pinuse(p));
+  assert (!is_mmapped(p));
+  if (p != m->dv && p != m->top) {
+    if (sz >= MIN_CHUNK_SIZE) {
+      assert((sz & CHUNK_ALIGN_MASK) == 0);
+      assert(is_aligned(chunk2mem(p)));
+      assert(next->prev_foot == sz);
+      assert(pinuse(p));
+      assert (next == m->top || is_inuse(next));
+      assert(p->fd->bk == p);
+      assert(p->bk->fd == p);
+    }
+    else  /* markers are always of size SIZE_T_SIZE */
+      assert(sz == SIZE_T_SIZE);
+  }
+}
+
+/* Check properties of malloced chunks at the point they are malloced */
+static void do_check_malloced_chunk(mstate m, void* mem, size_t s) {
+  if (mem != 0) {
+    mchunkptr p = mem2chunk(mem);
+    size_t sz = p->head & ~INUSE_BITS;
+    do_check_inuse_chunk(m, p);
+    assert((sz & CHUNK_ALIGN_MASK) == 0);
+    assert(sz >= MIN_CHUNK_SIZE);
+    assert(sz >= s);
+    /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */
+    assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE));
+  }
+}
+
+/* Check a tree and its subtrees.  */
+static void do_check_tree(mstate m, tchunkptr t) {
+  tchunkptr head = 0;
+  tchunkptr u = t;
+  bindex_t tindex = t->index;
+  size_t tsize = chunksize(t);
+  bindex_t idx;
+  compute_tree_index(tsize, idx);
+  assert(tindex == idx);
+  assert(tsize >= MIN_LARGE_SIZE);
+  assert(tsize >= minsize_for_tree_index(idx));
+  assert((idx == NTREEBINS-1) || (tsize < minsize_for_tree_index((idx+1))));
+
+  do { /* traverse through chain of same-sized nodes */
+    do_check_any_chunk(m, ((mchunkptr)u));
+    assert(u->index == tindex);
+    assert(chunksize(u) == tsize);
+    assert(!is_inuse(u));
+    assert(!next_pinuse(u));
+    assert(u->fd->bk == u);
+    assert(u->bk->fd == u);
+    if (u->parent == 0) {
+      assert(u->child[0] == 0);
+      assert(u->child[1] == 0);
+    }
+    else {
+      assert(head == 0); /* only one node on chain has parent */
+      head = u;
+      assert(u->parent != u);
+      assert (u->parent->child[0] == u ||
+              u->parent->child[1] == u ||
+              *((tbinptr*)(u->parent)) == u);
+      if (u->child[0] != 0) {
+        assert(u->child[0]->parent == u);
+        assert(u->child[0] != u);
+        do_check_tree(m, u->child[0]);
+      }
+      if (u->child[1] != 0) {
+        assert(u->child[1]->parent == u);
+        assert(u->child[1] != u);
+        do_check_tree(m, u->child[1]);
+      }
+      if (u->child[0] != 0 && u->child[1] != 0) {
+        assert(chunksize(u->child[0]) < chunksize(u->child[1]));
+      }
+    }
+    u = u->fd;
+  } while (u != t);
+  assert(head != 0);
+}
+
+/*  Check all the chunks in a treebin.  */
+static void do_check_treebin(mstate m, bindex_t i) {
+  tbinptr* tb = treebin_at(m, i);
+  tchunkptr t = *tb;
+  int empty = (m->treemap & (1U << i)) == 0;
+  if (t == 0)
+    assert(empty);
+  if (!empty)
+    do_check_tree(m, t);
+}
+
+/*  Check all the chunks in a smallbin.  */
+static void do_check_smallbin(mstate m, bindex_t i) {
+  sbinptr b = smallbin_at(m, i);
+  mchunkptr p = b->bk;
+  unsigned int empty = (m->smallmap & (1U << i)) == 0;
+  if (p == b)
+    assert(empty);
+  if (!empty) {
+    for (; p != b; p = p->bk) {
+      size_t size = chunksize(p);
+      mchunkptr q;
+      /* each chunk claims to be free */
+      do_check_free_chunk(m, p);
+      /* chunk belongs in bin */
+      assert(small_index(size) == i);
+      assert(p->bk == b || chunksize(p->bk) == chunksize(p));
+      /* chunk is followed by an inuse chunk */
+      q = next_chunk(p);
+      if (q->head != FENCEPOST_HEAD)
+        do_check_inuse_chunk(m, q);
+    }
+  }
+}
+
+/* Find x in a bin. Used in other check functions. */
+static int bin_find(mstate m, mchunkptr x) {
+  size_t size = chunksize(x);
+  if (is_small(size)) {
+    bindex_t sidx = small_index(size);
+    sbinptr b = smallbin_at(m, sidx);
+    if (smallmap_is_marked(m, sidx)) {
+      mchunkptr p = b;
+      do {
+        if (p == x)
+          return 1;
+      } while ((p = p->fd) != b);
+    }
+  }
+  else {
+    bindex_t tidx;
+    compute_tree_index(size, tidx);
+    if (treemap_is_marked(m, tidx)) {
+      tchunkptr t = *treebin_at(m, tidx);
+      size_t sizebits = size << leftshift_for_tree_index(tidx);
+      while (t != 0 && chunksize(t) != size) {
+        t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
+        sizebits <<= 1;
+      }
+      if (t != 0) {
+        tchunkptr u = t;
+        do {
+          if (u == (tchunkptr)x)
+            return 1;
+        } while ((u = u->fd) != t);
+      }
+    }
+  }
+  return 0;
+}
+
+/* Traverse each chunk and check it; return total */
+static size_t traverse_and_check(mstate m) {
+  size_t sum = 0;
+  if (is_initialized(m)) {
+    msegmentptr s = &m->seg;
+    sum += m->topsize + TOP_FOOT_SIZE;
+    while (s != 0) {
+      mchunkptr q = align_as_chunk(s->base);
+      mchunkptr lastq = 0;
+      assert(pinuse(q));
+      while (segment_holds(s, q) &&
+             q != m->top && q->head != FENCEPOST_HEAD) {
+        sum += chunksize(q);
+        if (is_inuse(q)) {
+          assert(!bin_find(m, q));
+          do_check_inuse_chunk(m, q);
+        }
+        else {
+          assert(q == m->dv || bin_find(m, q));
+          assert(lastq == 0 || is_inuse(lastq)); /* Not 2 consecutive free */
+          do_check_free_chunk(m, q);
+        }
+        lastq = q;
+        q = next_chunk(q);
+      }
+      s = s->next;
+    }
+  }
+  return sum;
+}
+
+
+/* Check all properties of malloc_state. */
+static void do_check_malloc_state(mstate m) {
+  bindex_t i;
+  size_t total;
+  /* check bins */
+  for (i = 0; i < NSMALLBINS; ++i)
+    do_check_smallbin(m, i);
+  for (i = 0; i < NTREEBINS; ++i)
+    do_check_treebin(m, i);
+
+  if (m->dvsize != 0) { /* check dv chunk */
+    do_check_any_chunk(m, m->dv);
+    assert(m->dvsize == chunksize(m->dv));
+    assert(m->dvsize >= MIN_CHUNK_SIZE);
+    assert(bin_find(m, m->dv) == 0);
+  }
+
+  if (m->top != 0) {   /* check top chunk */
+    do_check_top_chunk(m, m->top);
+    /*assert(m->topsize == chunksize(m->top)); redundant */
+    assert(m->topsize > 0);
+    assert(bin_find(m, m->top) == 0);
+  }
+
+  total = traverse_and_check(m);
+  assert(total <= m->footprint);
+  assert(m->footprint <= m->max_footprint);
+}
+#endif /* DEBUG */
+
+/* ----------------------------- statistics ------------------------------ */
+
+#if !NO_MALLINFO
+static struct mallinfo internal_mallinfo(mstate m) {
+  struct mallinfo nm = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 };
+  ensure_initialization();
+  if (!PREACTION(m)) {
+    check_malloc_state(m);
+    if (is_initialized(m)) {
+      size_t nfree = SIZE_T_ONE; /* top always free */
+      size_t mfree = m->topsize + TOP_FOOT_SIZE;
+      size_t sum = mfree;
+      msegmentptr s = &m->seg;
+      while (s != 0) {
+        mchunkptr q = align_as_chunk(s->base);
+        while (segment_holds(s, q) &&
+               q != m->top && q->head != FENCEPOST_HEAD) {
+          size_t sz = chunksize(q);
+          sum += sz;
+          if (!is_inuse(q)) {
+            mfree += sz;
+            ++nfree;
+          }
+          q = next_chunk(q);
+        }
+        s = s->next;
+      }
+
+      nm.arena    = sum;
+      nm.ordblks  = nfree;
+      nm.hblkhd   = m->footprint - sum;
+      nm.usmblks  = m->max_footprint;
+      nm.uordblks = m->footprint - mfree;
+      nm.fordblks = mfree;
+      nm.keepcost = m->topsize;
+    }
+
+    POSTACTION(m);
+  }
+  return nm;
+}
+#endif /* !NO_MALLINFO */
+
+#if !NO_MALLOC_STATS
+static void internal_malloc_stats(mstate m) {
+  ensure_initialization();
+  if (!PREACTION(m)) {
+    size_t maxfp = 0;
+    size_t fp = 0;
+    size_t used = 0;
+    check_malloc_state(m);
+    if (is_initialized(m)) {
+      msegmentptr s = &m->seg;
+      maxfp = m->max_footprint;
+      fp = m->footprint;
+      used = fp - (m->topsize + TOP_FOOT_SIZE);
+
+      while (s != 0) {
+        mchunkptr q = align_as_chunk(s->base);
+        while (segment_holds(s, q) &&
+               q != m->top && q->head != FENCEPOST_HEAD) {
+          if (!is_inuse(q))
+            used -= chunksize(q);
+          q = next_chunk(q);
+        }
+        s = s->next;
+      }
+    }
+    POSTACTION(m); /* drop lock */
+    fprintf(stderr, "max system bytes = %10lu\n", (unsigned long)(maxfp));
+    fprintf(stderr, "system bytes     = %10lu\n", (unsigned long)(fp));
+    fprintf(stderr, "in use bytes     = %10lu\n", (unsigned long)(used));
+  }
+}
+#endif /* NO_MALLOC_STATS */
+
+/* ----------------------- Operations on smallbins ----------------------- */
+
+/*
+  Various forms of linking and unlinking are defined as macros.  Even
+  the ones for trees, which are very long but have very short typical
+  paths.  This is ugly but reduces reliance on inlining support of
+  compilers.
+*/
+
+/* Link a free chunk into a smallbin  */
+#define insert_small_chunk(M, P, S) {\
+  bindex_t I  = small_index(S);\
+  mchunkptr B = smallbin_at(M, I);\
+  mchunkptr F = B;\
+  assert(S >= MIN_CHUNK_SIZE);\
+  if (!smallmap_is_marked(M, I))\
+    mark_smallmap(M, I);\
+  else if (RTCHECK(ok_address(M, B->fd)))\
+    F = B->fd;\
+  else {\
+    CORRUPTION_ERROR_ACTION(M);\
+  }\
+  B->fd = P;\
+  F->bk = P;\
+  P->fd = F;\
+  P->bk = B;\
+}
+
+/* Unlink a chunk from a smallbin  */
+#define unlink_small_chunk(M, P, S) {\
+  mchunkptr F = P->fd;\
+  mchunkptr B = P->bk;\
+  bindex_t I = small_index(S);\
+  assert(P != B);\
+  assert(P != F);\
+  assert(chunksize(P) == small_index2size(I));\
+  if (RTCHECK(F == smallbin_at(M,I) || (ok_address(M, F) && F->bk == P))) { \
+    if (B == F) {\
+      clear_smallmap(M, I);\
+    }\
+    else if (RTCHECK(B == smallbin_at(M,I) ||\
+                     (ok_address(M, B) && B->fd == P))) {\
+      F->bk = B;\
+      B->fd = F;\
+    }\
+    else {\
+      CORRUPTION_ERROR_ACTION(M);\
+    }\
+  }\
+  else {\
+    CORRUPTION_ERROR_ACTION(M);\
+  }\
+}
+
+/* Unlink the first chunk from a smallbin */
+#define unlink_first_small_chunk(M, B, P, I) {\
+  mchunkptr F = P->fd;\
+  assert(P != B);\
+  assert(P != F);\
+  assert(chunksize(P) == small_index2size(I));\
+  if (B == F) {\
+    clear_smallmap(M, I);\
+  }\
+  else if (RTCHECK(ok_address(M, F) && F->bk == P)) {\
+    F->bk = B;\
+    B->fd = F;\
+  }\
+  else {\
+    CORRUPTION_ERROR_ACTION(M);\
+  }\
+}
+
+/* Replace dv node, binning the old one */
+/* Used only when dvsize known to be small */
+#define replace_dv(M, P, S) {\
+  size_t DVS = M->dvsize;\
+  assert(is_small(DVS));\
+  if (DVS != 0) {\
+    mchunkptr DV = M->dv;\
+    insert_small_chunk(M, DV, DVS);\
+  }\
+  M->dvsize = S;\
+  M->dv = P;\
+}
+
+/* ------------------------- Operations on trees ------------------------- */
+
+/* Insert chunk into tree */
+#define insert_large_chunk(M, X, S) {\
+  tbinptr* H;\
+  bindex_t I;\
+  compute_tree_index(S, I);\
+  H = treebin_at(M, I);\
+  X->index = I;\
+  X->child[0] = X->child[1] = 0;\
+  if (!treemap_is_marked(M, I)) {\
+    mark_treemap(M, I);\
+    *H = X;\
+    X->parent = (tchunkptr)H;\
+    X->fd = X->bk = X;\
+  }\
+  else {\
+    tchunkptr T = *H;\
+    size_t K = S << leftshift_for_tree_index(I);\
+    for (;;) {\
+      if (chunksize(T) != S) {\
+        tchunkptr* C = &(T->child[(K >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1]);\
+        K <<= 1;\
+        if (*C != 0)\
+          T = *C;\
+        else if (RTCHECK(ok_address(M, C))) {\
+          *C = X;\
+          X->parent = T;\
+          X->fd = X->bk = X;\
+          break;\
+        }\
+        else {\
+          CORRUPTION_ERROR_ACTION(M);\
+          break;\
+        }\
+      }\
+      else {\
+        tchunkptr F = T->fd;\
+        if (RTCHECK(ok_address(M, T) && ok_address(M, F))) {\
+          T->fd = F->bk = X;\
+          X->fd = F;\
+          X->bk = T;\
+          X->parent = 0;\
+          break;\
+        }\
+        else {\
+          CORRUPTION_ERROR_ACTION(M);\
+          break;\
+        }\
+      }\
+    }\
+  }\
+}
+
+/*
+  Unlink steps:
+
+  1. If x is a chained node, unlink it from its same-sized fd/bk links
+     and choose its bk node as its replacement.
+  2. If x was the last node of its size, but not a leaf node, it must
+     be replaced with a leaf node (not merely one with an open left or
+     right), to make sure that lefts and rights of descendents
+     correspond properly to bit masks.  We use the rightmost descendent
+     of x.  We could use any other leaf, but this is easy to locate and
+     tends to counteract removal of leftmosts elsewhere, and so keeps
+     paths shorter than minimally guaranteed.  This doesn't loop much
+     because on average a node in a tree is near the bottom.
+  3. If x is the base of a chain (i.e., has parent links) relink
+     x's parent and children to x's replacement (or null if none).
+*/
+
+#define unlink_large_chunk(M, X) {\
+  tchunkptr XP = X->parent;\
+  tchunkptr R;\
+  if (X->bk != X) {\
+    tchunkptr F = X->fd;\
+    R = X->bk;\
+    if (RTCHECK(ok_address(M, F) && F->bk == X && R->fd == X)) {\
+      F->bk = R;\
+      R->fd = F;\
+    }\
+    else {\
+      CORRUPTION_ERROR_ACTION(M);\
+    }\
+  }\
+  else {\
+    tchunkptr* RP;\
+    if (((R = *(RP = &(X->child[1]))) != 0) ||\
+        ((R = *(RP = &(X->child[0]))) != 0)) {\
+      tchunkptr* CP;\
+      while ((*(CP = &(R->child[1])) != 0) ||\
+             (*(CP = &(R->child[0])) != 0)) {\
+        R = *(RP = CP);\
+      }\
+      if (RTCHECK(ok_address(M, RP)))\
+        *RP = 0;\
+      else {\
+        CORRUPTION_ERROR_ACTION(M);\
+      }\
+    }\
+  }\
+  if (XP != 0) {\
+    tbinptr* H = treebin_at(M, X->index);\
+    if (X == *H) {\
+      if ((*H = R) == 0) \
+        clear_treemap(M, X->index);\
+    }\
+    else if (RTCHECK(ok_address(M, XP))) {\
+      if (XP->child[0] == X) \
+        XP->child[0] = R;\
+      else \
+        XP->child[1] = R;\
+    }\
+    else\
+      CORRUPTION_ERROR_ACTION(M);\
+    if (R != 0) {\
+      if (RTCHECK(ok_address(M, R))) {\
+        tchunkptr C0, C1;\
+        R->parent = XP;\
+        if ((C0 = X->child[0]) != 0) {\
+          if (RTCHECK(ok_address(M, C0))) {\
+            R->child[0] = C0;\
+            C0->parent = R;\
+          }\
+          else\
+            CORRUPTION_ERROR_ACTION(M);\
+        }\
+        if ((C1 = X->child[1]) != 0) {\
+          if (RTCHECK(ok_address(M, C1))) {\
+            R->child[1] = C1;\
+            C1->parent = R;\
+          }\
+          else\
+            CORRUPTION_ERROR_ACTION(M);\
+        }\
+      }\
+      else\
+        CORRUPTION_ERROR_ACTION(M);\
+    }\
+  }\
+}
+
+/* Relays to large vs small bin operations */
+
+#define insert_chunk(M, P, S)\
+  if (is_small(S)) insert_small_chunk(M, P, S)\
+  else { tchunkptr TP = (tchunkptr)(P); insert_large_chunk(M, TP, S); }
+
+#define unlink_chunk(M, P, S)\
+  if (is_small(S)) unlink_small_chunk(M, P, S)\
+  else { tchunkptr TP = (tchunkptr)(P); unlink_large_chunk(M, TP); }
+
+
+/* Relays to internal calls to malloc/free from realloc, memalign etc */
+
+#if ONLY_MSPACES
+#define internal_malloc(m, b) mspace_malloc(m, b)
+#define internal_free(m, mem) mspace_free(m,mem);
+#else /* ONLY_MSPACES */
+#if MSPACES
+#define internal_malloc(m, b)\
+  ((m == gm)? dlmalloc(b) : mspace_malloc(m, b))
+#define internal_free(m, mem)\
+   if (m == gm) dlfree(mem); else mspace_free(m,mem);
+#else /* MSPACES */
+#define internal_malloc(m, b) dlmalloc(b)
+#define internal_free(m, mem) dlfree(mem)
+#endif /* MSPACES */
+#endif /* ONLY_MSPACES */
+
+/* -----------------------  Direct-mmapping chunks ----------------------- */
+
+/*
+  Directly mmapped chunks are set up with an offset to the start of
+  the mmapped region stored in the prev_foot field of the chunk. This
+  allows reconstruction of the required argument to MUNMAP when freed,
+  and also allows adjustment of the returned chunk to meet alignment
+  requirements (especially in memalign).
+*/
+
+/* Malloc using mmap */
+static void* mmap_alloc(mstate m, size_t nb) {
+  size_t mmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
+  if (m->footprint_limit != 0) {
+    size_t fp = m->footprint + mmsize;
+    if (fp <= m->footprint || fp > m->footprint_limit)
+      return 0;
+  }
+  if (mmsize > nb) {     /* Check for wrap around 0 */
+    char* mm = (char*)(CALL_DIRECT_MMAP(mmsize));
+    if (mm != CMFAIL) {
+      size_t offset = align_offset(chunk2mem(mm));
+      size_t psize = mmsize - offset - MMAP_FOOT_PAD;
+      mchunkptr p = (mchunkptr)(mm + offset);
+      p->prev_foot = offset;
+      p->head = psize;
+      mark_inuse_foot(m, p, psize);
+      chunk_plus_offset(p, psize)->head = FENCEPOST_HEAD;
+      chunk_plus_offset(p, psize+SIZE_T_SIZE)->head = 0;
+
+      if (m->least_addr == 0 || mm < m->least_addr)
+        m->least_addr = mm;
+      if ((m->footprint += mmsize) > m->max_footprint)
+        m->max_footprint = m->footprint;
+      assert(is_aligned(chunk2mem(p)));
+      check_mmapped_chunk(m, p);
+      return chunk2mem(p);
+    }
+  }
+  return 0;
+}
+
+/* Realloc using mmap */
+static mchunkptr mmap_resize(mstate m, mchunkptr oldp, size_t nb, int flags) {
+  size_t oldsize = chunksize(oldp);
+  (void)flags; /* placate people compiling -Wunused */
+  if (is_small(nb)) /* Can't shrink mmap regions below small size */
+    return 0;
+  /* Keep old chunk if big enough but not too big */
+  if (oldsize >= nb + SIZE_T_SIZE &&
+      (oldsize - nb) <= (mparams.granularity << 1))
+    return oldp;
+  else {
+    size_t offset = oldp->prev_foot;
+    size_t oldmmsize = oldsize + offset + MMAP_FOOT_PAD;
+    size_t newmmsize = mmap_align(nb + SIX_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
+    char* cp = (char*)CALL_MREMAP((char*)oldp - offset,
+                                  oldmmsize, newmmsize, flags);
+    if (cp != CMFAIL) {
+      mchunkptr newp = (mchunkptr)(cp + offset);
+      size_t psize = newmmsize - offset - MMAP_FOOT_PAD;
+      newp->head = psize;
+      mark_inuse_foot(m, newp, psize);
+      chunk_plus_offset(newp, psize)->head = FENCEPOST_HEAD;
+      chunk_plus_offset(newp, psize+SIZE_T_SIZE)->head = 0;
+
+      if (cp < m->least_addr)
+        m->least_addr = cp;
+      if ((m->footprint += newmmsize - oldmmsize) > m->max_footprint)
+        m->max_footprint = m->footprint;
+      check_mmapped_chunk(m, newp);
+      return newp;
+    }
+  }
+  return 0;
+}
+
+
+/* -------------------------- mspace management -------------------------- */
+
+/* Initialize top chunk and its size */
+static void init_top(mstate m, mchunkptr p, size_t psize) {
+  /* Ensure alignment */
+  size_t offset = align_offset(chunk2mem(p));
+  p = (mchunkptr)((char*)p + offset);
+  psize -= offset;
+
+  m->top = p;
+  m->topsize = psize;
+  p->head = psize | PINUSE_BIT;
+  /* set size of fake trailing chunk holding overhead space only once */
+  chunk_plus_offset(p, psize)->head = TOP_FOOT_SIZE;
+  m->trim_check = mparams.trim_threshold; /* reset on each update */
+}
+
+/* Initialize bins for a new mstate that is otherwise zeroed out */
+static void init_bins(mstate m) {
+  /* Establish circular links for smallbins */
+  bindex_t i;
+  for (i = 0; i < NSMALLBINS; ++i) {
+    sbinptr bin = smallbin_at(m,i);
+    bin->fd = bin->bk = bin;
+  }
+}
+
+#if PROCEED_ON_ERROR
+
+/* default corruption action */
+static void reset_on_error(mstate m) {
+  int i;
+  ++malloc_corruption_error_count;
+  /* Reinitialize fields to forget about all memory */
+  m->smallmap = m->treemap = 0;
+  m->dvsize = m->topsize = 0;
+  m->seg.base = 0;
+  m->seg.size = 0;
+  m->seg.next = 0;
+  m->top = m->dv = 0;
+  for (i = 0; i < NTREEBINS; ++i)
+    *treebin_at(m, i) = 0;
+  init_bins(m);
+}
+#endif /* PROCEED_ON_ERROR */
+
+/* Allocate chunk and prepend remainder with chunk in successor base. */
+static void* prepend_alloc(mstate m, char* newbase, char* oldbase,
+                           size_t nb) {
+  mchunkptr p = align_as_chunk(newbase);
+  mchunkptr oldfirst = align_as_chunk(oldbase);
+  size_t psize = (char*)oldfirst - (char*)p;
+  mchunkptr q = chunk_plus_offset(p, nb);
+  size_t qsize = psize - nb;
+  set_size_and_pinuse_of_inuse_chunk(m, p, nb);
+
+  assert((char*)oldfirst > (char*)q);
+  assert(pinuse(oldfirst));
+  assert(qsize >= MIN_CHUNK_SIZE);
+
+  /* consolidate remainder with first chunk of old base */
+  if (oldfirst == m->top) {
+    size_t tsize = m->topsize += qsize;
+    m->top = q;
+    q->head = tsize | PINUSE_BIT;
+    check_top_chunk(m, q);
+  }
+  else if (oldfirst == m->dv) {
+    size_t dsize = m->dvsize += qsize;
+    m->dv = q;
+    set_size_and_pinuse_of_free_chunk(q, dsize);
+  }
+  else {
+    if (!is_inuse(oldfirst)) {
+      size_t nsize = chunksize(oldfirst);
+      unlink_chunk(m, oldfirst, nsize);
+      oldfirst = chunk_plus_offset(oldfirst, nsize);
+      qsize += nsize;
+    }
+    set_free_with_pinuse(q, qsize, oldfirst);
+    insert_chunk(m, q, qsize);
+    check_free_chunk(m, q);
+  }
+
+  check_malloced_chunk(m, chunk2mem(p), nb);
+  return chunk2mem(p);
+}
+
+/* Add a segment to hold a new noncontiguous region */
+static void add_segment(mstate m, char* tbase, size_t tsize, flag_t mmapped) {
+  /* Determine locations and sizes of segment, fenceposts, old top */
+  char* old_top = (char*)m->top;
+  msegmentptr oldsp = segment_holding(m, old_top);
+  char* old_end = oldsp->base + oldsp->size;
+  size_t ssize = pad_request(sizeof(struct malloc_segment));
+  char* rawsp = old_end - (ssize + FOUR_SIZE_T_SIZES + CHUNK_ALIGN_MASK);
+  size_t offset = align_offset(chunk2mem(rawsp));
+  char* asp = rawsp + offset;
+  char* csp = (asp < (old_top + MIN_CHUNK_SIZE))? old_top : asp;
+  mchunkptr sp = (mchunkptr)csp;
+  msegmentptr ss = (msegmentptr)(chunk2mem(sp));
+  mchunkptr tnext = chunk_plus_offset(sp, ssize);
+  mchunkptr p = tnext;
+  int nfences = 0;
+
+  /* reset top to new space */
+  init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
+
+  /* Set up segment record */
+  assert(is_aligned(ss));
+  set_size_and_pinuse_of_inuse_chunk(m, sp, ssize);
+  *ss = m->seg; /* Push current record */
+  m->seg.base = tbase;
+  m->seg.size = tsize;
+  m->seg.sflags = mmapped;
+  m->seg.next = ss;
+
+  /* Insert trailing fenceposts */
+  for (;;) {
+    mchunkptr nextp = chunk_plus_offset(p, SIZE_T_SIZE);
+    p->head = FENCEPOST_HEAD;
+    ++nfences;
+    if ((char*)(&(nextp->head)) < old_end)
+      p = nextp;
+    else
+      break;
+  }
+  assert(nfences >= 2);
+
+  /* Insert the rest of old top into a bin as an ordinary free chunk */
+  if (csp != old_top) {
+    mchunkptr q = (mchunkptr)old_top;
+    size_t psize = csp - old_top;
+    mchunkptr tn = chunk_plus_offset(q, psize);
+    set_free_with_pinuse(q, psize, tn);
+    insert_chunk(m, q, psize);
+  }
+
+  check_top_chunk(m, m->top);
+}
+
+/* -------------------------- System allocation -------------------------- */
+
+/* Get memory from system using MORECORE or MMAP */
+static void* sys_alloc(mstate m, size_t nb) {
+  char* tbase = CMFAIL;
+  size_t tsize = 0;
+  flag_t mmap_flag = 0;
+  size_t asize; /* allocation size */
+
+  ensure_initialization();
+
+  /* Directly map large chunks, but only if already initialized */
+  if (use_mmap(m) && nb >= mparams.mmap_threshold && m->topsize != 0) {
+    void* mem = mmap_alloc(m, nb);
+    if (mem != 0)
+      return mem;
+  }
+
+  asize = granularity_align(nb + SYS_ALLOC_PADDING);
+  if (asize <= nb)
+    return 0; /* wraparound */
+  if (m->footprint_limit != 0) {
+    size_t fp = m->footprint + asize;
+    if (fp <= m->footprint || fp > m->footprint_limit)
+      return 0;
+  }
+
+  /*
+    Try getting memory in any of three ways (in most-preferred to
+    least-preferred order):
+    1. A call to MORECORE that can normally contiguously extend memory.
+       (disabled if not MORECORE_CONTIGUOUS or not HAVE_MORECORE or
+       or main space is mmapped or a previous contiguous call failed)
+    2. A call to MMAP new space (disabled if not HAVE_MMAP).
+       Note that under the default settings, if MORECORE is unable to
+       fulfill a request, and HAVE_MMAP is true, then mmap is
+       used as a noncontiguous system allocator. This is a useful backup
+       strategy for systems with holes in address spaces -- in this case
+       sbrk cannot contiguously expand the heap, but mmap may be able to
+       find space.
+    3. A call to MORECORE that cannot usually contiguously extend memory.
+       (disabled if not HAVE_MORECORE)
+
+   In all cases, we need to request enough bytes from system to ensure
+   we can malloc nb bytes upon success, so pad with enough space for
+   top_foot, plus alignment-pad to make sure we don't lose bytes if
+   not on boundary, and round this up to a granularity unit.
+  */
+
+  if (MORECORE_CONTIGUOUS && !use_noncontiguous(m)) {
+    char* br = CMFAIL;
+    size_t ssize = asize; /* sbrk call size */
+    msegmentptr ss = (m->top == 0)? 0 : segment_holding(m, (char*)m->top);
+    ACQUIRE_MALLOC_GLOBAL_LOCK();
+
+    if (ss == 0) {  /* First time through or recovery */
+      char* base = (char*)CALL_MORECORE(0);
+      if (base != CMFAIL) {
+        size_t fp;
+        /* Adjust to end on a page boundary */
+        if (!is_page_aligned(base))
+          ssize += (page_align((size_t)base) - (size_t)base);
+        fp = m->footprint + ssize; /* recheck limits */
+        if (ssize > nb && ssize < HALF_MAX_SIZE_T &&
+            (m->footprint_limit == 0 ||
+             (fp > m->footprint && fp <= m->footprint_limit)) &&
+            (br = (char*)(CALL_MORECORE(ssize))) == base) {
+          tbase = base;
+          tsize = ssize;
+        }
+      }
+    }
+    else {
+      /* Subtract out existing available top space from MORECORE request. */
+      ssize = granularity_align(nb - m->topsize + SYS_ALLOC_PADDING);
+      /* Use mem here only if it did continuously extend old space */
+      if (ssize < HALF_MAX_SIZE_T &&
+          (br = (char*)(CALL_MORECORE(ssize))) == ss->base+ss->size) {
+        tbase = br;
+        tsize = ssize;
+      }
+    }
+
+    if (tbase == CMFAIL) {    /* Cope with partial failure */
+      if (br != CMFAIL) {    /* Try to use/extend the space we did get */
+        if (ssize < HALF_MAX_SIZE_T &&
+            ssize < nb + SYS_ALLOC_PADDING) {
+          size_t esize = granularity_align(nb + SYS_ALLOC_PADDING - ssize);
+          if (esize < HALF_MAX_SIZE_T) {
+            char* end = (char*)CALL_MORECORE(esize);
+            if (end != CMFAIL)
+              ssize += esize;
+            else {            /* Can't use; try to release */
+              (void) CALL_MORECORE(-ssize);
+              br = CMFAIL;
+            }
+          }
+        }
+      }
+      if (br != CMFAIL) {    /* Use the space we did get */
+        tbase = br;
+        tsize = ssize;
+      }
+      else
+        disable_contiguous(m); /* Don't try contiguous path in the future */
+    }
+
+    RELEASE_MALLOC_GLOBAL_LOCK();
+  }
+
+  if (HAVE_MMAP && tbase == CMFAIL) {  /* Try MMAP */
+    char* mp = (char*)(CALL_MMAP(asize));
+    if (mp != CMFAIL) {
+      tbase = mp;
+      tsize = asize;
+      mmap_flag = USE_MMAP_BIT;
+    }
+  }
+
+  if (HAVE_MORECORE && tbase == CMFAIL) { /* Try noncontiguous MORECORE */
+    if (asize < HALF_MAX_SIZE_T) {
+      char* br = CMFAIL;
+      char* end = CMFAIL;
+      ACQUIRE_MALLOC_GLOBAL_LOCK();
+      br = (char*)(CALL_MORECORE(asize));
+      end = (char*)(CALL_MORECORE(0));
+      RELEASE_MALLOC_GLOBAL_LOCK();
+      if (br != CMFAIL && end != CMFAIL && br < end) {
+        size_t ssize = end - br;
+        if (ssize > nb + TOP_FOOT_SIZE) {
+          tbase = br;
+          tsize = ssize;
+        }
+      }
+    }
+  }
+
+  if (tbase != CMFAIL) {
+
+    if ((m->footprint += tsize) > m->max_footprint)
+      m->max_footprint = m->footprint;
+
+    if (!is_initialized(m)) { /* first-time initialization */
+      if (m->least_addr == 0 || tbase < m->least_addr)
+        m->least_addr = tbase;
+      m->seg.base = tbase;
+      m->seg.size = tsize;
+      m->seg.sflags = mmap_flag;
+      m->magic = mparams.magic;
+      m->release_checks = MAX_RELEASE_CHECK_RATE;
+      init_bins(m);
+#if !ONLY_MSPACES
+      if (is_global(m))
+        init_top(m, (mchunkptr)tbase, tsize - TOP_FOOT_SIZE);
+      else
+#endif
+      {
+        /* Offset top by embedded malloc_state */
+        mchunkptr mn = next_chunk(mem2chunk(m));
+        init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) -TOP_FOOT_SIZE);
+      }
+    }
+
+    else {
+      /* Try to merge with an existing segment */
+      msegmentptr sp = &m->seg;
+      /* Only consider most recent segment if traversal suppressed */
+      while (sp != 0 && tbase != sp->base + sp->size)
+        sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next;
+      if (sp != 0 &&
+          !is_extern_segment(sp) &&
+          (sp->sflags & USE_MMAP_BIT) == mmap_flag &&
+          segment_holds(sp, m->top)) { /* append */
+        sp->size += tsize;
+        init_top(m, m->top, m->topsize + tsize);
+      }
+      else {
+        if (tbase < m->least_addr)
+          m->least_addr = tbase;
+        sp = &m->seg;
+        while (sp != 0 && sp->base != tbase + tsize)
+          sp = (NO_SEGMENT_TRAVERSAL) ? 0 : sp->next;
+        if (sp != 0 &&
+            !is_extern_segment(sp) &&
+            (sp->sflags & USE_MMAP_BIT) == mmap_flag) {
+          char* oldbase = sp->base;
+          sp->base = tbase;
+          sp->size += tsize;
+          return prepend_alloc(m, tbase, oldbase, nb);
+        }
+        else
+          add_segment(m, tbase, tsize, mmap_flag);
+      }
+    }
+
+    if (nb < m->topsize) { /* Allocate from new or extended top space */
+      size_t rsize = m->topsize -= nb;
+      mchunkptr p = m->top;
+      mchunkptr r = m->top = chunk_plus_offset(p, nb);
+      r->head = rsize | PINUSE_BIT;
+      set_size_and_pinuse_of_inuse_chunk(m, p, nb);
+      check_top_chunk(m, m->top);
+      check_malloced_chunk(m, chunk2mem(p), nb);
+      return chunk2mem(p);
+    }
+  }
+
+  MALLOC_FAILURE_ACTION;
+  return 0;
+}
+
+/* -----------------------  system deallocation -------------------------- */
+
+/* Unmap and unlink any mmapped segments that don't contain used chunks */
+static size_t release_unused_segments(mstate m) {
+  size_t released = 0;
+  int nsegs = 0;
+  msegmentptr pred = &m->seg;
+  msegmentptr sp = pred->next;
+  while (sp != 0) {
+    char* base = sp->base;
+    size_t size = sp->size;
+    msegmentptr next = sp->next;
+    ++nsegs;
+    if (is_mmapped_segment(sp) && !is_extern_segment(sp)) {
+      mchunkptr p = align_as_chunk(base);
+      size_t psize = chunksize(p);
+      /* Can unmap if first chunk holds entire segment and not pinned */
+      if (!is_inuse(p) && (char*)p + psize >= base + size - TOP_FOOT_SIZE) {
+        tchunkptr tp = (tchunkptr)p;
+        assert(segment_holds(sp, (char*)sp));
+        if (p == m->dv) {
+          m->dv = 0;
+          m->dvsize = 0;
+        }
+        else {
+          unlink_large_chunk(m, tp);
+        }
+        if (CALL_MUNMAP(base, size) == 0) {
+          released += size;
+          m->footprint -= size;
+          /* unlink obsoleted record */
+          sp = pred;
+          sp->next = next;
+        }
+        else { /* back out if cannot unmap */
+          insert_large_chunk(m, tp, psize);
+        }
+      }
+    }
+    if (NO_SEGMENT_TRAVERSAL) /* scan only first segment */
+      break;
+    pred = sp;
+    sp = next;
+  }
+  /* Reset check counter */
+  m->release_checks = (((size_t) nsegs > (size_t) MAX_RELEASE_CHECK_RATE)?
+                       (size_t) nsegs : (size_t) MAX_RELEASE_CHECK_RATE);
+  return released;
+}
+
+static int sys_trim(mstate m, size_t pad) {
+  size_t released = 0;
+  ensure_initialization();
+  if (pad < MAX_REQUEST && is_initialized(m)) {
+    pad += TOP_FOOT_SIZE; /* ensure enough room for segment overhead */
+
+    if (m->topsize > pad) {
+      /* Shrink top space in granularity-size units, keeping at least one */
+      size_t unit = mparams.granularity;
+      size_t extra = ((m->topsize - pad + (unit - SIZE_T_ONE)) / unit -
+                      SIZE_T_ONE) * unit;
+      msegmentptr sp = segment_holding(m, (char*)m->top);
+
+      if (!is_extern_segment(sp)) {
+        if (is_mmapped_segment(sp)) {
+          if (HAVE_MMAP &&
+              sp->size >= extra &&
+              !has_segment_link(m, sp)) { /* can't shrink if pinned */
+            size_t newsize = sp->size - extra;
+            (void)newsize; /* placate people compiling -Wunused-variable */
+            /* Prefer mremap, fall back to munmap */
+            if ((CALL_MREMAP(sp->base, sp->size, newsize, 0) != MFAIL) ||
+                (CALL_MUNMAP(sp->base + newsize, extra) == 0)) {
+              released = extra;
+            }
+          }
+        }
+        else if (HAVE_MORECORE) {
+          if (extra >= HALF_MAX_SIZE_T) /* Avoid wrapping negative */
+            extra = (HALF_MAX_SIZE_T) + SIZE_T_ONE - unit;
+          ACQUIRE_MALLOC_GLOBAL_LOCK();
+          {
+            /* Make sure end of memory is where we last set it. */
+            char* old_br = (char*)(CALL_MORECORE(0));
+            if (old_br == sp->base + sp->size) {
+              char* rel_br = (char*)(CALL_MORECORE(-extra));
+              char* new_br = (char*)(CALL_MORECORE(0));
+              if (rel_br != CMFAIL && new_br < old_br)
+                released = old_br - new_br;
+            }
+          }
+          RELEASE_MALLOC_GLOBAL_LOCK();
+        }
+      }
+
+      if (released != 0) {
+        sp->size -= released;
+        m->footprint -= released;
+        init_top(m, m->top, m->topsize - released);
+        check_top_chunk(m, m->top);
+      }
+    }
+
+    /* Unmap any unused mmapped segments */
+    if (HAVE_MMAP)
+      released += release_unused_segments(m);
+
+    /* On failure, disable autotrim to avoid repeated failed future calls */
+    if (released == 0 && m->topsize > m->trim_check)
+      m->trim_check = MAX_SIZE_T;
+  }
+
+  return (released != 0)? 1 : 0;
+}
+
+/* Consolidate and bin a chunk. Differs from exported versions
+   of free mainly in that the chunk need not be marked as inuse.
+*/
+static void dispose_chunk(mstate m, mchunkptr p, size_t psize) {
+  mchunkptr next = chunk_plus_offset(p, psize);
+  if (!pinuse(p)) {
+    mchunkptr prev;
+    size_t prevsize = p->prev_foot;
+    if (is_mmapped(p)) {
+      psize += prevsize + MMAP_FOOT_PAD;
+      if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
+        m->footprint -= psize;
+      return;
+    }
+    prev = chunk_minus_offset(p, prevsize);
+    psize += prevsize;
+    p = prev;
+    if (RTCHECK(ok_address(m, prev))) { /* consolidate backward */
+      if (p != m->dv) {
+        unlink_chunk(m, p, prevsize);
+      }
+      else if ((next->head & INUSE_BITS) == INUSE_BITS) {
+        m->dvsize = psize;
+        set_free_with_pinuse(p, psize, next);
+        return;
+      }
+    }
+    else {
+      CORRUPTION_ERROR_ACTION(m);
+      return;
+    }
+  }
+  if (RTCHECK(ok_address(m, next))) {
+    if (!cinuse(next)) {  /* consolidate forward */
+      if (next == m->top) {
+        size_t tsize = m->topsize += psize;
+        m->top = p;
+        p->head = tsize | PINUSE_BIT;
+        if (p == m->dv) {
+          m->dv = 0;
+          m->dvsize = 0;
+        }
+        return;
+      }
+      else if (next == m->dv) {
+        size_t dsize = m->dvsize += psize;
+        m->dv = p;
+        set_size_and_pinuse_of_free_chunk(p, dsize);
+        return;
+      }
+      else {
+        size_t nsize = chunksize(next);
+        psize += nsize;
+        unlink_chunk(m, next, nsize);
+        set_size_and_pinuse_of_free_chunk(p, psize);
+        if (p == m->dv) {
+          m->dvsize = psize;
+          return;
+        }
+      }
+    }
+    else {
+      set_free_with_pinuse(p, psize, next);
+    }
+    insert_chunk(m, p, psize);
+  }
+  else {
+    CORRUPTION_ERROR_ACTION(m);
+  }
+}
+
+/* ---------------------------- malloc --------------------------- */
+
+/* allocate a large request from the best fitting chunk in a treebin */
+static void* tmalloc_large(mstate m, size_t nb) {
+  tchunkptr v = 0;
+  size_t rsize = -nb; /* Unsigned negation */
+  tchunkptr t;
+  bindex_t idx;
+  compute_tree_index(nb, idx);
+  if ((t = *treebin_at(m, idx)) != 0) {
+    /* Traverse tree for this bin looking for node with size == nb */
+    size_t sizebits = nb << leftshift_for_tree_index(idx);
+    tchunkptr rst = 0;  /* The deepest untaken right subtree */
+    for (;;) {
+      tchunkptr rt;
+      size_t trem = chunksize(t) - nb;
+      if (trem < rsize) {
+        v = t;
+        if ((rsize = trem) == 0)
+          break;
+      }
+      rt = t->child[1];
+      t = t->child[(sizebits >> (SIZE_T_BITSIZE-SIZE_T_ONE)) & 1];
+      if (rt != 0 && rt != t)
+        rst = rt;
+      if (t == 0) {
+        t = rst; /* set t to least subtree holding sizes > nb */
+        break;
+      }
+      sizebits <<= 1;
+    }
+  }
+  if (t == 0 && v == 0) { /* set t to root of next non-empty treebin */
+    binmap_t leftbits = left_bits(idx2bit(idx)) & m->treemap;
+    if (leftbits != 0) {
+      bindex_t i;
+      binmap_t leastbit = least_bit(leftbits);
+      compute_bit2idx(leastbit, i);
+      t = *treebin_at(m, i);
+    }
+  }
+
+  while (t != 0) { /* find smallest of tree or subtree */
+    size_t trem = chunksize(t) - nb;
+    if (trem < rsize) {
+      rsize = trem;
+      v = t;
+    }
+    t = leftmost_child(t);
+  }
+
+  /*  If dv is a better fit, return 0 so malloc will use it */
+  if (v != 0 && rsize < (size_t)(m->dvsize - nb)) {
+    if (RTCHECK(ok_address(m, v))) { /* split */
+      mchunkptr r = chunk_plus_offset(v, nb);
+      assert(chunksize(v) == rsize + nb);
+      if (RTCHECK(ok_next(v, r))) {
+        unlink_large_chunk(m, v);
+        if (rsize < MIN_CHUNK_SIZE)
+          set_inuse_and_pinuse(m, v, (rsize + nb));
+        else {
+          set_size_and_pinuse_of_inuse_chunk(m, v, nb);
+          set_size_and_pinuse_of_free_chunk(r, rsize);
+          insert_chunk(m, r, rsize);
+        }
+        return chunk2mem(v);
+      }
+    }
+    CORRUPTION_ERROR_ACTION(m);
+  }
+  return 0;
+}
+
+/* allocate a small request from the best fitting chunk in a treebin */
+static void* tmalloc_small(mstate m, size_t nb) {
+  tchunkptr t, v;
+  size_t rsize;
+  bindex_t i;
+  binmap_t leastbit = least_bit(m->treemap);
+  compute_bit2idx(leastbit, i);
+  v = t = *treebin_at(m, i);
+  rsize = chunksize(t) - nb;
+
+  while ((t = leftmost_child(t)) != 0) {
+    size_t trem = chunksize(t) - nb;
+    if (trem < rsize) {
+      rsize = trem;
+      v = t;
+    }
+  }
+
+  if (RTCHECK(ok_address(m, v))) {
+    mchunkptr r = chunk_plus_offset(v, nb);
+    assert(chunksize(v) == rsize + nb);
+    if (RTCHECK(ok_next(v, r))) {
+      unlink_large_chunk(m, v);
+      if (rsize < MIN_CHUNK_SIZE)
+        set_inuse_and_pinuse(m, v, (rsize + nb));
+      else {
+        set_size_and_pinuse_of_inuse_chunk(m, v, nb);
+        set_size_and_pinuse_of_free_chunk(r, rsize);
+        replace_dv(m, r, rsize);
+      }
+      return chunk2mem(v);
+    }
+  }
+
+  CORRUPTION_ERROR_ACTION(m);
+  return 0;
+}
+
+#if !ONLY_MSPACES
+
+void* dlmalloc(size_t bytes) {
+  /*
+     Basic algorithm:
+     If a small request (< 256 bytes minus per-chunk overhead):
+       1. If one exists, use a remainderless chunk in associated smallbin.
+          (Remainderless means that there are too few excess bytes to
+          represent as a chunk.)
+       2. If it is big enough, use the dv chunk, which is normally the
+          chunk adjacent to the one used for the most recent small request.
+       3. If one exists, split the smallest available chunk in a bin,
+          saving remainder in dv.
+       4. If it is big enough, use the top chunk.
+       5. If available, get memory from system and use it
+     Otherwise, for a large request:
+       1. Find the smallest available binned chunk that fits, and use it
+          if it is better fitting than dv chunk, splitting if necessary.
+       2. If better fitting than any binned chunk, use the dv chunk.
+       3. If it is big enough, use the top chunk.
+       4. If request size >= mmap threshold, try to directly mmap this chunk.
+       5. If available, get memory from system and use it
+
+     The ugly goto's here ensure that postaction occurs along all paths.
+  */
+
+#if USE_LOCKS
+  ensure_initialization(); /* initialize in sys_alloc if not using locks */
+#endif
+
+  if (!PREACTION(gm)) {
+    void* mem;
+    size_t nb;
+    if (bytes <= MAX_SMALL_REQUEST) {
+      bindex_t idx;
+      binmap_t smallbits;
+      nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
+      idx = small_index(nb);
+      smallbits = gm->smallmap >> idx;
+
+      if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
+        mchunkptr b, p;
+        idx += ~smallbits & 1;       /* Uses next bin if idx empty */
+        b = smallbin_at(gm, idx);
+        p = b->fd;
+        assert(chunksize(p) == small_index2size(idx));
+        unlink_first_small_chunk(gm, b, p, idx);
+        set_inuse_and_pinuse(gm, p, small_index2size(idx));
+        mem = chunk2mem(p);
+        check_malloced_chunk(gm, mem, nb);
+        goto postaction;
+      }
+
+      else if (nb > gm->dvsize) {
+        if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
+          mchunkptr b, p, r;
+          size_t rsize;
+          bindex_t i;
+          binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
+          binmap_t leastbit = least_bit(leftbits);
+          compute_bit2idx(leastbit, i);
+          b = smallbin_at(gm, i);
+          p = b->fd;
+          assert(chunksize(p) == small_index2size(i));
+          unlink_first_small_chunk(gm, b, p, i);
+          rsize = small_index2size(i) - nb;
+          /* Fit here cannot be remainderless if 4byte sizes */
+          if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
+            set_inuse_and_pinuse(gm, p, small_index2size(i));
+          else {
+            set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
+            r = chunk_plus_offset(p, nb);
+            set_size_and_pinuse_of_free_chunk(r, rsize);
+            replace_dv(gm, r, rsize);
+          }
+          mem = chunk2mem(p);
+          check_malloced_chunk(gm, mem, nb);
+          goto postaction;
+        }
+
+        else if (gm->treemap != 0 && (mem = tmalloc_small(gm, nb)) != 0) {
+          check_malloced_chunk(gm, mem, nb);
+          goto postaction;
+        }
+      }
+    }
+    else if (bytes >= MAX_REQUEST)
+      nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
+    else {
+      nb = pad_request(bytes);
+      if (gm->treemap != 0 && (mem = tmalloc_large(gm, nb)) != 0) {
+        check_malloced_chunk(gm, mem, nb);
+        goto postaction;
+      }
+    }
+
+    if (nb <= gm->dvsize) {
+      size_t rsize = gm->dvsize - nb;
+      mchunkptr p = gm->dv;
+      if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
+        mchunkptr r = gm->dv = chunk_plus_offset(p, nb);
+        gm->dvsize = rsize;
+        set_size_and_pinuse_of_free_chunk(r, rsize);
+        set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
+      }
+      else { /* exhaust dv */
+        size_t dvs = gm->dvsize;
+        gm->dvsize = 0;
+        gm->dv = 0;
+        set_inuse_and_pinuse(gm, p, dvs);
+      }
+      mem = chunk2mem(p);
+      check_malloced_chunk(gm, mem, nb);
+      goto postaction;
+    }
+
+    else if (nb < gm->topsize) { /* Split top */
+      size_t rsize = gm->topsize -= nb;
+      mchunkptr p = gm->top;
+      mchunkptr r = gm->top = chunk_plus_offset(p, nb);
+      r->head = rsize | PINUSE_BIT;
+      set_size_and_pinuse_of_inuse_chunk(gm, p, nb);
+      mem = chunk2mem(p);
+      check_top_chunk(gm, gm->top);
+      check_malloced_chunk(gm, mem, nb);
+      goto postaction;
+    }
+
+    mem = sys_alloc(gm, nb);
+
+  postaction:
+    POSTACTION(gm);
+    return mem;
+  }
+
+  return 0;
+}
+
+/* ---------------------------- free --------------------------- */
+
+void dlfree(void* mem) {
+  /*
+     Consolidate freed chunks with preceeding or succeeding bordering
+     free chunks, if they exist, and then place in a bin.  Intermixed
+     with special cases for top, dv, mmapped chunks, and usage errors.
+  */
+
+  if (mem != 0) {
+    mchunkptr p  = mem2chunk(mem);
+#if FOOTERS
+    mstate fm = get_mstate_for(p);
+    if (!ok_magic(fm)) {
+      USAGE_ERROR_ACTION(fm, p);
+      return;
+    }
+#else /* FOOTERS */
+#define fm gm
+#endif /* FOOTERS */
+    if (!PREACTION(fm)) {
+      check_inuse_chunk(fm, p);
+      if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
+        size_t psize = chunksize(p);
+        mchunkptr next = chunk_plus_offset(p, psize);
+        if (!pinuse(p)) {
+          size_t prevsize = p->prev_foot;
+          if (is_mmapped(p)) {
+            psize += prevsize + MMAP_FOOT_PAD;
+            if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
+              fm->footprint -= psize;
+            goto postaction;
+          }
+          else {
+            mchunkptr prev = chunk_minus_offset(p, prevsize);
+            psize += prevsize;
+            p = prev;
+            if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
+              if (p != fm->dv) {
+                unlink_chunk(fm, p, prevsize);
+              }
+              else if ((next->head & INUSE_BITS) == INUSE_BITS) {
+                fm->dvsize = psize;
+                set_free_with_pinuse(p, psize, next);
+                goto postaction;
+              }
+            }
+            else
+              goto erroraction;
+          }
+        }
+
+        if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
+          if (!cinuse(next)) {  /* consolidate forward */
+            if (next == fm->top) {
+              size_t tsize = fm->topsize += psize;
+              fm->top = p;
+              p->head = tsize | PINUSE_BIT;
+              if (p == fm->dv) {
+                fm->dv = 0;
+                fm->dvsize = 0;
+              }
+              if (should_trim(fm, tsize))
+                sys_trim(fm, 0);
+              goto postaction;
+            }
+            else if (next == fm->dv) {
+              size_t dsize = fm->dvsize += psize;
+              fm->dv = p;
+              set_size_and_pinuse_of_free_chunk(p, dsize);
+              goto postaction;
+            }
+            else {
+              size_t nsize = chunksize(next);
+              psize += nsize;
+              unlink_chunk(fm, next, nsize);
+              set_size_and_pinuse_of_free_chunk(p, psize);
+              if (p == fm->dv) {
+                fm->dvsize = psize;
+                goto postaction;
+              }
+            }
+          }
+          else
+            set_free_with_pinuse(p, psize, next);
+
+          if (is_small(psize)) {
+            insert_small_chunk(fm, p, psize);
+            check_free_chunk(fm, p);
+          }
+          else {
+            tchunkptr tp = (tchunkptr)p;
+            insert_large_chunk(fm, tp, psize);
+            check_free_chunk(fm, p);
+            if (--fm->release_checks == 0)
+              release_unused_segments(fm);
+          }
+          goto postaction;
+        }
+      }
+    erroraction:
+      USAGE_ERROR_ACTION(fm, p);
+    postaction:
+      POSTACTION(fm);
+    }
+  }
+#if !FOOTERS
+#undef fm
+#endif /* FOOTERS */
+}
+
+void* dlcalloc(size_t n_elements, size_t elem_size) {
+  void* mem;
+  size_t req = 0;
+  if (n_elements != 0) {
+    req = n_elements * elem_size;
+    if (((n_elements | elem_size) & ~(size_t)0xffff) &&
+        (req / n_elements != elem_size))
+      req = MAX_SIZE_T; /* force downstream failure on overflow */
+  }
+  mem = dlmalloc(req);
+  if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
+    memset(mem, 0, req);
+  return mem;
+}
+
+#endif /* !ONLY_MSPACES */
+
+/* ------------ Internal support for realloc, memalign, etc -------------- */
+
+/* Try to realloc; only in-place unless can_move true */
+static mchunkptr try_realloc_chunk(mstate m, mchunkptr p, size_t nb,
+                                   int can_move) {
+  mchunkptr newp = 0;
+  size_t oldsize = chunksize(p);
+  mchunkptr next = chunk_plus_offset(p, oldsize);
+  if (RTCHECK(ok_address(m, p) && ok_inuse(p) &&
+              ok_next(p, next) && ok_pinuse(next))) {
+    if (is_mmapped(p)) {
+      newp = mmap_resize(m, p, nb, can_move);
+    }
+    else if (oldsize >= nb) {             /* already big enough */
+      size_t rsize = oldsize - nb;
+      if (rsize >= MIN_CHUNK_SIZE) {      /* split off remainder */
+        mchunkptr r = chunk_plus_offset(p, nb);
+        set_inuse(m, p, nb);
+        set_inuse(m, r, rsize);
+        dispose_chunk(m, r, rsize);
+      }
+      newp = p;
+    }
+    else if (next == m->top) {  /* extend into top */
+      if (oldsize + m->topsize > nb) {
+        size_t newsize = oldsize + m->topsize;
+        size_t newtopsize = newsize - nb;
+        mchunkptr newtop = chunk_plus_offset(p, nb);
+        set_inuse(m, p, nb);
+        newtop->head = newtopsize |PINUSE_BIT;
+        m->top = newtop;
+        m->topsize = newtopsize;
+        newp = p;
+      }
+    }
+    else if (next == m->dv) { /* extend into dv */
+      size_t dvs = m->dvsize;
+      if (oldsize + dvs >= nb) {
+        size_t dsize = oldsize + dvs - nb;
+        if (dsize >= MIN_CHUNK_SIZE) {
+          mchunkptr r = chunk_plus_offset(p, nb);
+          mchunkptr n = chunk_plus_offset(r, dsize);
+          set_inuse(m, p, nb);
+          set_size_and_pinuse_of_free_chunk(r, dsize);
+          clear_pinuse(n);
+          m->dvsize = dsize;
+          m->dv = r;
+        }
+        else { /* exhaust dv */
+          size_t newsize = oldsize + dvs;
+          set_inuse(m, p, newsize);
+          m->dvsize = 0;
+          m->dv = 0;
+        }
+        newp = p;
+      }
+    }
+    else if (!cinuse(next)) { /* extend into next free chunk */
+      size_t nextsize = chunksize(next);
+      if (oldsize + nextsize >= nb) {
+        size_t rsize = oldsize + nextsize - nb;
+        unlink_chunk(m, next, nextsize);
+        if (rsize < MIN_CHUNK_SIZE) {
+          size_t newsize = oldsize + nextsize;
+          set_inuse(m, p, newsize);
+        }
+        else {
+          mchunkptr r = chunk_plus_offset(p, nb);
+          set_inuse(m, p, nb);
+          set_inuse(m, r, rsize);
+          dispose_chunk(m, r, rsize);
+        }
+        newp = p;
+      }
+    }
+  }
+  else {
+    USAGE_ERROR_ACTION(m, chunk2mem(p));
+  }
+  return newp;
+}
+
+static void* internal_memalign(mstate m, size_t alignment, size_t bytes) {
+  void* mem = 0;
+  if (alignment <  MIN_CHUNK_SIZE) /* must be at least a minimum chunk size */
+    alignment = MIN_CHUNK_SIZE;
+  if ((alignment & (alignment-SIZE_T_ONE)) != 0) {/* Ensure a power of 2 */
+    size_t a = MALLOC_ALIGNMENT << 1;
+    while (a < alignment) a <<= 1;
+    alignment = a;
+  }
+  if (bytes >= MAX_REQUEST - alignment) {
+    if (m != 0)  { /* Test isn't needed but avoids compiler warning */
+      MALLOC_FAILURE_ACTION;
+    }
+  }
+  else {
+    size_t nb = request2size(bytes);
+    size_t req = nb + alignment + MIN_CHUNK_SIZE - CHUNK_OVERHEAD;
+    mem = internal_malloc(m, req);
+    if (mem != 0) {
+      mchunkptr p = mem2chunk(mem);
+      if (PREACTION(m))
+        return 0;
+      if ((((size_t)(mem)) & (alignment - 1)) != 0) { /* misaligned */
+        /*
+          Find an aligned spot inside chunk.  Since we need to give
+          back leading space in a chunk of at least MIN_CHUNK_SIZE, if
+          the first calculation places us at a spot with less than
+          MIN_CHUNK_SIZE leader, we can move to the next aligned spot.
+          We've allocated enough total room so that this is always
+          possible.
+        */
+        char* br = (char*)mem2chunk((size_t)(((size_t)((char*)mem + alignment -
+                                                       SIZE_T_ONE)) &
+                                             -alignment));
+        char* pos = ((size_t)(br - (char*)(p)) >= MIN_CHUNK_SIZE)?
+          br : br+alignment;
+        mchunkptr newp = (mchunkptr)pos;
+        size_t leadsize = pos - (char*)(p);
+        size_t newsize = chunksize(p) - leadsize;
+
+        if (is_mmapped(p)) { /* For mmapped chunks, just adjust offset */
+          newp->prev_foot = p->prev_foot + leadsize;
+          newp->head = newsize;
+        }
+        else { /* Otherwise, give back leader, use the rest */
+          set_inuse(m, newp, newsize);
+          set_inuse(m, p, leadsize);
+          dispose_chunk(m, p, leadsize);
+        }
+        p = newp;
+      }
+
+      /* Give back spare room at the end */
+      if (!is_mmapped(p)) {
+        size_t size = chunksize(p);
+        if (size > nb + MIN_CHUNK_SIZE) {
+          size_t remainder_size = size - nb;
+          mchunkptr remainder = chunk_plus_offset(p, nb);
+          set_inuse(m, p, nb);
+          set_inuse(m, remainder, remainder_size);
+          dispose_chunk(m, remainder, remainder_size);
+        }
+      }
+
+      mem = chunk2mem(p);
+      assert (chunksize(p) >= nb);
+      assert(((size_t)mem & (alignment - 1)) == 0);
+      check_inuse_chunk(m, p);
+      POSTACTION(m);
+    }
+  }
+  return mem;
+}
+
+/*
+  Common support for independent_X routines, handling
+    all of the combinations that can result.
+  The opts arg has:
+    bit 0 set if all elements are same size (using sizes[0])
+    bit 1 set if elements should be zeroed
+*/
+static void** ialloc(mstate m,
+                     size_t n_elements,
+                     size_t* sizes,
+                     int opts,
+                     void* chunks[]) {
+
+  size_t    element_size;   /* chunksize of each element, if all same */
+  size_t    contents_size;  /* total size of elements */
+  size_t    array_size;     /* request size of pointer array */
+  void*     mem;            /* malloced aggregate space */
+  mchunkptr p;              /* corresponding chunk */
+  size_t    remainder_size; /* remaining bytes while splitting */
+  void**    marray;         /* either "chunks" or malloced ptr array */
+  mchunkptr array_chunk;    /* chunk for malloced ptr array */
+  flag_t    was_enabled;    /* to disable mmap */
+  size_t    size;
+  size_t    i;
+
+  ensure_initialization();
+  /* compute array length, if needed */
+  if (chunks != 0) {
+    if (n_elements == 0)
+      return chunks; /* nothing to do */
+    marray = chunks;
+    array_size = 0;
+  }
+  else {
+    /* if empty req, must still return chunk representing empty array */
+    if (n_elements == 0)
+      return (void**)internal_malloc(m, 0);
+    marray = 0;
+    array_size = request2size(n_elements * (sizeof(void*)));
+  }
+
+  /* compute total element size */
+  if (opts & 0x1) { /* all-same-size */
+    element_size = request2size(*sizes);
+    contents_size = n_elements * element_size;
+  }
+  else { /* add up all the sizes */
+    element_size = 0;
+    contents_size = 0;
+    for (i = 0; i != n_elements; ++i)
+      contents_size += request2size(sizes[i]);
+  }
+
+  size = contents_size + array_size;
+
+  /*
+     Allocate the aggregate chunk.  First disable direct-mmapping so
+     malloc won't use it, since we would not be able to later
+     free/realloc space internal to a segregated mmap region.
+  */
+  was_enabled = use_mmap(m);
+  disable_mmap(m);
+  mem = internal_malloc(m, size - CHUNK_OVERHEAD);
+  if (was_enabled)
+    enable_mmap(m);
+  if (mem == 0)
+    return 0;
+
+  if (PREACTION(m)) return 0;
+  p = mem2chunk(mem);
+  remainder_size = chunksize(p);
+
+  assert(!is_mmapped(p));
+
+  if (opts & 0x2) {       /* optionally clear the elements */
+    memset((size_t*)mem, 0, remainder_size - SIZE_T_SIZE - array_size);
+  }
+
+  /* If not provided, allocate the pointer array as final part of chunk */
+  if (marray == 0) {
+    size_t  array_chunk_size;
+    array_chunk = chunk_plus_offset(p, contents_size);
+    array_chunk_size = remainder_size - contents_size;
+    marray = (void**) (chunk2mem(array_chunk));
+    set_size_and_pinuse_of_inuse_chunk(m, array_chunk, array_chunk_size);
+    remainder_size = contents_size;
+  }
+
+  /* split out elements */
+  for (i = 0; ; ++i) {
+    marray[i] = chunk2mem(p);
+    if (i != n_elements-1) {
+      if (element_size != 0)
+        size = element_size;
+      else
+        size = request2size(sizes[i]);
+      remainder_size -= size;
+      set_size_and_pinuse_of_inuse_chunk(m, p, size);
+      p = chunk_plus_offset(p, size);
+    }
+    else { /* the final element absorbs any overallocation slop */
+      set_size_and_pinuse_of_inuse_chunk(m, p, remainder_size);
+      break;
+    }
+  }
+
+#if DEBUG
+  if (marray != chunks) {
+    /* final element must have exactly exhausted chunk */
+    if (element_size != 0) {
+      assert(remainder_size == element_size);
+    }
+    else {
+      assert(remainder_size == request2size(sizes[i]));
+    }
+    check_inuse_chunk(m, mem2chunk(marray));
+  }
+  for (i = 0; i != n_elements; ++i)
+    check_inuse_chunk(m, mem2chunk(marray[i]));
+
+#endif /* DEBUG */
+
+  POSTACTION(m);
+  return marray;
+}
+
+/* Try to free all pointers in the given array.
+   Note: this could be made faster, by delaying consolidation,
+   at the price of disabling some user integrity checks, We
+   still optimize some consolidations by combining adjacent
+   chunks before freeing, which will occur often if allocated
+   with ialloc or the array is sorted.
+*/
+static size_t internal_bulk_free(mstate m, void* array[], size_t nelem) {
+  size_t unfreed = 0;
+  if (!PREACTION(m)) {
+    void** a;
+    void** fence = &(array[nelem]);
+    for (a = array; a != fence; ++a) {
+      void* mem = *a;
+      if (mem != 0) {
+        mchunkptr p = mem2chunk(mem);
+        size_t psize = chunksize(p);
+#if FOOTERS
+        if (get_mstate_for(p) != m) {
+          ++unfreed;
+          continue;
+        }
+#endif
+        check_inuse_chunk(m, p);
+        *a = 0;
+        if (RTCHECK(ok_address(m, p) && ok_inuse(p))) {
+          void ** b = a + 1; /* try to merge with next chunk */
+          mchunkptr next = next_chunk(p);
+          if (b != fence && *b == chunk2mem(next)) {
+            size_t newsize = chunksize(next) + psize;
+            set_inuse(m, p, newsize);
+            *b = chunk2mem(p);
+          }
+          else
+            dispose_chunk(m, p, psize);
+        }
+        else {
+          CORRUPTION_ERROR_ACTION(m);
+          break;
+        }
+      }
+    }
+    if (should_trim(m, m->topsize))
+      sys_trim(m, 0);
+    POSTACTION(m);
+  }
+  return unfreed;
+}
+
+/* Traversal */
+#if MALLOC_INSPECT_ALL
+static void internal_inspect_all(mstate m,
+                                 void(*handler)(void *start,
+                                                void *end,
+                                                size_t used_bytes,
+                                                void* callback_arg),
+                                 void* arg) {
+  if (is_initialized(m)) {
+    mchunkptr top = m->top;
+    msegmentptr s;
+    for (s = &m->seg; s != 0; s = s->next) {
+      mchunkptr q = align_as_chunk(s->base);
+      while (segment_holds(s, q) && q->head != FENCEPOST_HEAD) {
+        mchunkptr next = next_chunk(q);
+        size_t sz = chunksize(q);
+        size_t used;
+        void* start;
+        if (is_inuse(q)) {
+          used = sz - CHUNK_OVERHEAD; /* must not be mmapped */
+          start = chunk2mem(q);
+        }
+        else {
+          used = 0;
+          if (is_small(sz)) {     /* offset by possible bookkeeping */
+            start = (void*)((char*)q + sizeof(struct malloc_chunk));
+          }
+          else {
+            start = (void*)((char*)q + sizeof(struct malloc_tree_chunk));
+          }
+        }
+        if (start < (void*)next)  /* skip if all space is bookkeeping */
+          handler(start, next, used, arg);
+        if (q == top)
+          break;
+        q = next;
+      }
+    }
+  }
+}
+#endif /* MALLOC_INSPECT_ALL */
+
+/* ------------------ Exported realloc, memalign, etc -------------------- */
+
+#if !ONLY_MSPACES
+
+void* dlrealloc(void* oldmem, size_t bytes) {
+  void* mem = 0;
+  if (oldmem == 0) {
+    mem = dlmalloc(bytes);
+  }
+  else if (bytes >= MAX_REQUEST) {
+    MALLOC_FAILURE_ACTION;
+  }
+#ifdef REALLOC_ZERO_BYTES_FREES
+  else if (bytes == 0) {
+    dlfree(oldmem);
+  }
+#endif /* REALLOC_ZERO_BYTES_FREES */
+  else {
+    size_t nb = request2size(bytes);
+    mchunkptr oldp = mem2chunk(oldmem);
+#if ! FOOTERS
+    mstate m = gm;
+#else /* FOOTERS */
+    mstate m = get_mstate_for(oldp);
+    if (!ok_magic(m)) {
+      USAGE_ERROR_ACTION(m, oldmem);
+      return 0;
+    }
+#endif /* FOOTERS */
+    if (!PREACTION(m)) {
+      mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1);
+      POSTACTION(m);
+      if (newp != 0) {
+        check_inuse_chunk(m, newp);
+        mem = chunk2mem(newp);
+      }
+      else {
+        mem = internal_malloc(m, bytes);
+        if (mem != 0) {
+          size_t oc = chunksize(oldp) - overhead_for(oldp);
+          memcpy(mem, oldmem, (oc < bytes)? oc : bytes);
+          internal_free(m, oldmem);
+        }
+      }
+    }
+  }
+  return mem;
+}
+
+void* dlrealloc_in_place(void* oldmem, size_t bytes) {
+  void* mem = 0;
+  if (oldmem != 0) {
+    if (bytes >= MAX_REQUEST) {
+      MALLOC_FAILURE_ACTION;
+    }
+    else {
+      size_t nb = request2size(bytes);
+      mchunkptr oldp = mem2chunk(oldmem);
+#if ! FOOTERS
+      mstate m = gm;
+#else /* FOOTERS */
+      mstate m = get_mstate_for(oldp);
+      if (!ok_magic(m)) {
+        USAGE_ERROR_ACTION(m, oldmem);
+        return 0;
+      }
+#endif /* FOOTERS */
+      if (!PREACTION(m)) {
+        mchunkptr newp = try_realloc_chunk(m, oldp, nb, 0);
+        POSTACTION(m);
+        if (newp == oldp) {
+          check_inuse_chunk(m, newp);
+          mem = oldmem;
+        }
+      }
+    }
+  }
+  return mem;
+}
+
+void* dlmemalign(size_t alignment, size_t bytes) {
+  if (alignment <= MALLOC_ALIGNMENT) {
+    return dlmalloc(bytes);
+  }
+  return internal_memalign(gm, alignment, bytes);
+}
+
+int dlposix_memalign(void** pp, size_t alignment, size_t bytes) {
+  void* mem = 0;
+  if (alignment == MALLOC_ALIGNMENT)
+    mem = dlmalloc(bytes);
+  else {
+    size_t d = alignment / sizeof(void*);
+    size_t r = alignment % sizeof(void*);
+    if (r != 0 || d == 0 || (d & (d-SIZE_T_ONE)) != 0)
+      return EINVAL;
+    else if (bytes <= MAX_REQUEST - alignment) {
+      if (alignment <  MIN_CHUNK_SIZE)
+        alignment = MIN_CHUNK_SIZE;
+      mem = internal_memalign(gm, alignment, bytes);
+    }
+  }
+  if (mem == 0)
+    return ENOMEM;
+  else {
+    *pp = mem;
+    return 0;
+  }
+}
+
+void* dlvalloc(size_t bytes) {
+  size_t pagesz;
+  ensure_initialization();
+  pagesz = mparams.page_size;
+  return dlmemalign(pagesz, bytes);
+}
+
+void* dlpvalloc(size_t bytes) {
+  size_t pagesz;
+  ensure_initialization();
+  pagesz = mparams.page_size;
+  return dlmemalign(pagesz, (bytes + pagesz - SIZE_T_ONE) & ~(pagesz - SIZE_T_ONE));
+}
+
+void** dlindependent_calloc(size_t n_elements, size_t elem_size,
+                            void* chunks[]) {
+  size_t sz = elem_size; /* serves as 1-element array */
+  return ialloc(gm, n_elements, &sz, 3, chunks);
+}
+
+void** dlindependent_comalloc(size_t n_elements, size_t sizes[],
+                              void* chunks[]) {
+  return ialloc(gm, n_elements, sizes, 0, chunks);
+}
+
+size_t dlbulk_free(void* array[], size_t nelem) {
+  return internal_bulk_free(gm, array, nelem);
+}
+
+#if MALLOC_INSPECT_ALL
+void dlmalloc_inspect_all(void(*handler)(void *start,
+                                         void *end,
+                                         size_t used_bytes,
+                                         void* callback_arg),
+                          void* arg) {
+  ensure_initialization();
+  if (!PREACTION(gm)) {
+    internal_inspect_all(gm, handler, arg);
+    POSTACTION(gm);
+  }
+}
+#endif /* MALLOC_INSPECT_ALL */
+
+int dlmalloc_trim(size_t pad) {
+  int result = 0;
+  ensure_initialization();
+  if (!PREACTION(gm)) {
+    result = sys_trim(gm, pad);
+    POSTACTION(gm);
+  }
+  return result;
+}
+
+size_t dlmalloc_footprint(void) {
+  return gm->footprint;
+}
+
+size_t dlmalloc_max_footprint(void) {
+  return gm->max_footprint;
+}
+
+size_t dlmalloc_footprint_limit(void) {
+  size_t maf = gm->footprint_limit;
+  return maf == 0 ? MAX_SIZE_T : maf;
+}
+
+size_t dlmalloc_set_footprint_limit(size_t bytes) {
+  size_t result;  /* invert sense of 0 */
+  if (bytes == 0)
+    result = granularity_align(1); /* Use minimal size */
+  if (bytes == MAX_SIZE_T)
+    result = 0;                    /* disable */
+  else
+    result = granularity_align(bytes);
+  return gm->footprint_limit = result;
+}
+
+#if !NO_MALLINFO
+struct mallinfo dlmallinfo(void) {
+  return internal_mallinfo(gm);
+}
+#endif /* NO_MALLINFO */
+
+#if !NO_MALLOC_STATS
+void dlmalloc_stats() {
+  internal_malloc_stats(gm);
+}
+#endif /* NO_MALLOC_STATS */
+
+int dlmallopt(int param_number, int value) {
+  return change_mparam(param_number, value);
+}
+
+size_t dlmalloc_usable_size(void* mem) {
+  if (mem != 0) {
+    mchunkptr p = mem2chunk(mem);
+    if (is_inuse(p))
+      return chunksize(p) - overhead_for(p);
+  }
+  return 0;
+}
+
+#endif /* !ONLY_MSPACES */
+
+/* ----------------------------- user mspaces ---------------------------- */
+
+#if MSPACES
+
+static mstate init_user_mstate(char* tbase, size_t tsize) {
+  size_t msize = pad_request(sizeof(struct malloc_state));
+  mchunkptr mn;
+  mchunkptr msp = align_as_chunk(tbase);
+  mstate m = (mstate)(chunk2mem(msp));
+  memset(m, 0, msize);
+  (void)INITIAL_LOCK(&m->mutex);
+  msp->head = (msize|INUSE_BITS);
+  m->seg.base = m->least_addr = tbase;
+  m->seg.size = m->footprint = m->max_footprint = tsize;
+  m->magic = mparams.magic;
+  m->release_checks = MAX_RELEASE_CHECK_RATE;
+  m->mflags = mparams.default_mflags;
+  m->extp = 0;
+  m->exts = 0;
+  disable_contiguous(m);
+  init_bins(m);
+  mn = next_chunk(mem2chunk(m));
+  init_top(m, mn, (size_t)((tbase + tsize) - (char*)mn) - TOP_FOOT_SIZE);
+  check_top_chunk(m, m->top);
+  return m;
+}
+
+mspace create_mspace(size_t capacity, int locked) {
+  mstate m = 0;
+  size_t msize;
+  ensure_initialization();
+  msize = pad_request(sizeof(struct malloc_state));
+  if (capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
+    size_t rs = ((capacity == 0)? mparams.granularity :
+                 (capacity + TOP_FOOT_SIZE + msize));
+    size_t tsize = granularity_align(rs);
+    char* tbase = (char*)(CALL_MMAP(tsize));
+    if (tbase != CMFAIL) {
+      m = init_user_mstate(tbase, tsize);
+      m->seg.sflags = USE_MMAP_BIT;
+      set_lock(m, locked);
+    }
+  }
+  return (mspace)m;
+}
+
+mspace create_mspace_with_base(void* base, size_t capacity, int locked) {
+  mstate m = 0;
+  size_t msize;
+  ensure_initialization();
+  msize = pad_request(sizeof(struct malloc_state));
+  if (capacity > msize + TOP_FOOT_SIZE &&
+      capacity < (size_t) -(msize + TOP_FOOT_SIZE + mparams.page_size)) {
+    m = init_user_mstate((char*)base, capacity);
+    m->seg.sflags = EXTERN_BIT;
+    set_lock(m, locked);
+  }
+  return (mspace)m;
+}
+
+int mspace_track_large_chunks(mspace msp, int enable) {
+  int ret = 0;
+  mstate ms = (mstate)msp;
+  if (!PREACTION(ms)) {
+    if (!use_mmap(ms)) {
+      ret = 1;
+    }
+    if (!enable) {
+      enable_mmap(ms);
+    } else {
+      disable_mmap(ms);
+    }
+    POSTACTION(ms);
+  }
+  return ret;
+}
+
+size_t destroy_mspace(mspace msp) {
+  size_t freed = 0;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    msegmentptr sp = &ms->seg;
+    (void)DESTROY_LOCK(&ms->mutex); /* destroy before unmapped */
+    while (sp != 0) {
+      char* base = sp->base;
+      size_t size = sp->size;
+      flag_t flag = sp->sflags;
+      (void)base; /* placate people compiling -Wunused-variable */
+      sp = sp->next;
+      if ((flag & USE_MMAP_BIT) && !(flag & EXTERN_BIT) &&
+          CALL_MUNMAP(base, size) == 0)
+        freed += size;
+    }
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return freed;
+}
+
+/*
+  mspace versions of routines are near-clones of the global
+  versions. This is not so nice but better than the alternatives.
+*/
+
+void* mspace_malloc(mspace msp, size_t bytes) {
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  if (!PREACTION(ms)) {
+    void* mem;
+    size_t nb;
+    if (bytes <= MAX_SMALL_REQUEST) {
+      bindex_t idx;
+      binmap_t smallbits;
+      nb = (bytes < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(bytes);
+      idx = small_index(nb);
+      smallbits = ms->smallmap >> idx;
+
+      if ((smallbits & 0x3U) != 0) { /* Remainderless fit to a smallbin. */
+        mchunkptr b, p;
+        idx += ~smallbits & 1;       /* Uses next bin if idx empty */
+        b = smallbin_at(ms, idx);
+        p = b->fd;
+        assert(chunksize(p) == small_index2size(idx));
+        unlink_first_small_chunk(ms, b, p, idx);
+        set_inuse_and_pinuse(ms, p, small_index2size(idx));
+        mem = chunk2mem(p);
+        check_malloced_chunk(ms, mem, nb);
+        goto postaction;
+      }
+
+      else if (nb > ms->dvsize) {
+        if (smallbits != 0) { /* Use chunk in next nonempty smallbin */
+          mchunkptr b, p, r;
+          size_t rsize;
+          bindex_t i;
+          binmap_t leftbits = (smallbits << idx) & left_bits(idx2bit(idx));
+          binmap_t leastbit = least_bit(leftbits);
+          compute_bit2idx(leastbit, i);
+          b = smallbin_at(ms, i);
+          p = b->fd;
+          assert(chunksize(p) == small_index2size(i));
+          unlink_first_small_chunk(ms, b, p, i);
+          rsize = small_index2size(i) - nb;
+          /* Fit here cannot be remainderless if 4byte sizes */
+          if (SIZE_T_SIZE != 4 && rsize < MIN_CHUNK_SIZE)
+            set_inuse_and_pinuse(ms, p, small_index2size(i));
+          else {
+            set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
+            r = chunk_plus_offset(p, nb);
+            set_size_and_pinuse_of_free_chunk(r, rsize);
+            replace_dv(ms, r, rsize);
+          }
+          mem = chunk2mem(p);
+          check_malloced_chunk(ms, mem, nb);
+          goto postaction;
+        }
+
+        else if (ms->treemap != 0 && (mem = tmalloc_small(ms, nb)) != 0) {
+          check_malloced_chunk(ms, mem, nb);
+          goto postaction;
+        }
+      }
+    }
+    else if (bytes >= MAX_REQUEST)
+      nb = MAX_SIZE_T; /* Too big to allocate. Force failure (in sys alloc) */
+    else {
+      nb = pad_request(bytes);
+      if (ms->treemap != 0 && (mem = tmalloc_large(ms, nb)) != 0) {
+        check_malloced_chunk(ms, mem, nb);
+        goto postaction;
+      }
+    }
+
+    if (nb <= ms->dvsize) {
+      size_t rsize = ms->dvsize - nb;
+      mchunkptr p = ms->dv;
+      if (rsize >= MIN_CHUNK_SIZE) { /* split dv */
+        mchunkptr r = ms->dv = chunk_plus_offset(p, nb);
+        ms->dvsize = rsize;
+        set_size_and_pinuse_of_free_chunk(r, rsize);
+        set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
+      }
+      else { /* exhaust dv */
+        size_t dvs = ms->dvsize;
+        ms->dvsize = 0;
+        ms->dv = 0;
+        set_inuse_and_pinuse(ms, p, dvs);
+      }
+      mem = chunk2mem(p);
+      check_malloced_chunk(ms, mem, nb);
+      goto postaction;
+    }
+
+    else if (nb < ms->topsize) { /* Split top */
+      size_t rsize = ms->topsize -= nb;
+      mchunkptr p = ms->top;
+      mchunkptr r = ms->top = chunk_plus_offset(p, nb);
+      r->head = rsize | PINUSE_BIT;
+      set_size_and_pinuse_of_inuse_chunk(ms, p, nb);
+      mem = chunk2mem(p);
+      check_top_chunk(ms, ms->top);
+      check_malloced_chunk(ms, mem, nb);
+      goto postaction;
+    }
+
+    mem = sys_alloc(ms, nb);
+
+  postaction:
+    POSTACTION(ms);
+    return mem;
+  }
+
+  return 0;
+}
+
+void mspace_free(mspace msp, void* mem) {
+  if (mem != 0) {
+    mchunkptr p  = mem2chunk(mem);
+#if FOOTERS
+    mstate fm = get_mstate_for(p);
+    (void)msp; /* placate people compiling -Wunused */
+#else /* FOOTERS */
+    mstate fm = (mstate)msp;
+#endif /* FOOTERS */
+    if (!ok_magic(fm)) {
+      USAGE_ERROR_ACTION(fm, p);
+      return;
+    }
+    if (!PREACTION(fm)) {
+      check_inuse_chunk(fm, p);
+      if (RTCHECK(ok_address(fm, p) && ok_inuse(p))) {
+        size_t psize = chunksize(p);
+        mchunkptr next = chunk_plus_offset(p, psize);
+        if (!pinuse(p)) {
+          size_t prevsize = p->prev_foot;
+          if (is_mmapped(p)) {
+            psize += prevsize + MMAP_FOOT_PAD;
+            if (CALL_MUNMAP((char*)p - prevsize, psize) == 0)
+              fm->footprint -= psize;
+            goto postaction;
+          }
+          else {
+            mchunkptr prev = chunk_minus_offset(p, prevsize);
+            psize += prevsize;
+            p = prev;
+            if (RTCHECK(ok_address(fm, prev))) { /* consolidate backward */
+              if (p != fm->dv) {
+                unlink_chunk(fm, p, prevsize);
+              }
+              else if ((next->head & INUSE_BITS) == INUSE_BITS) {
+                fm->dvsize = psize;
+                set_free_with_pinuse(p, psize, next);
+                goto postaction;
+              }
+            }
+            else
+              goto erroraction;
+          }
+        }
+
+        if (RTCHECK(ok_next(p, next) && ok_pinuse(next))) {
+          if (!cinuse(next)) {  /* consolidate forward */
+            if (next == fm->top) {
+              size_t tsize = fm->topsize += psize;
+              fm->top = p;
+              p->head = tsize | PINUSE_BIT;
+              if (p == fm->dv) {
+                fm->dv = 0;
+                fm->dvsize = 0;
+              }
+              if (should_trim(fm, tsize))
+                sys_trim(fm, 0);
+              goto postaction;
+            }
+            else if (next == fm->dv) {
+              size_t dsize = fm->dvsize += psize;
+              fm->dv = p;
+              set_size_and_pinuse_of_free_chunk(p, dsize);
+              goto postaction;
+            }
+            else {
+              size_t nsize = chunksize(next);
+              psize += nsize;
+              unlink_chunk(fm, next, nsize);
+              set_size_and_pinuse_of_free_chunk(p, psize);
+              if (p == fm->dv) {
+                fm->dvsize = psize;
+                goto postaction;
+              }
+            }
+          }
+          else
+            set_free_with_pinuse(p, psize, next);
+
+          if (is_small(psize)) {
+            insert_small_chunk(fm, p, psize);
+            check_free_chunk(fm, p);
+          }
+          else {
+            tchunkptr tp = (tchunkptr)p;
+            insert_large_chunk(fm, tp, psize);
+            check_free_chunk(fm, p);
+            if (--fm->release_checks == 0)
+              release_unused_segments(fm);
+          }
+          goto postaction;
+        }
+      }
+    erroraction:
+      USAGE_ERROR_ACTION(fm, p);
+    postaction:
+      POSTACTION(fm);
+    }
+  }
+}
+
+void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size) {
+  void* mem;
+  size_t req = 0;
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  if (n_elements != 0) {
+    req = n_elements * elem_size;
+    if (((n_elements | elem_size) & ~(size_t)0xffff) &&
+        (req / n_elements != elem_size))
+      req = MAX_SIZE_T; /* force downstream failure on overflow */
+  }
+  mem = internal_malloc(ms, req);
+  if (mem != 0 && calloc_must_clear(mem2chunk(mem)))
+    memset(mem, 0, req);
+  return mem;
+}
+
+void* mspace_realloc(mspace msp, void* oldmem, size_t bytes) {
+  void* mem = 0;
+  if (oldmem == 0) {
+    mem = mspace_malloc(msp, bytes);
+  }
+  else if (bytes >= MAX_REQUEST) {
+    MALLOC_FAILURE_ACTION;
+  }
+#ifdef REALLOC_ZERO_BYTES_FREES
+  else if (bytes == 0) {
+    mspace_free(msp, oldmem);
+  }
+#endif /* REALLOC_ZERO_BYTES_FREES */
+  else {
+    size_t nb = request2size(bytes);
+    mchunkptr oldp = mem2chunk(oldmem);
+#if ! FOOTERS
+    mstate m = (mstate)msp;
+#else /* FOOTERS */
+    mstate m = get_mstate_for(oldp);
+    if (!ok_magic(m)) {
+      USAGE_ERROR_ACTION(m, oldmem);
+      return 0;
+    }
+#endif /* FOOTERS */
+    if (!PREACTION(m)) {
+      mchunkptr newp = try_realloc_chunk(m, oldp, nb, 1);
+      POSTACTION(m);
+      if (newp != 0) {
+        check_inuse_chunk(m, newp);
+        mem = chunk2mem(newp);
+      }
+      else {
+        mem = mspace_malloc(m, bytes);
+        if (mem != 0) {
+          size_t oc = chunksize(oldp) - overhead_for(oldp);
+          memcpy(mem, oldmem, (oc < bytes)? oc : bytes);
+          mspace_free(m, oldmem);
+        }
+      }
+    }
+  }
+  return mem;
+}
+
+void* mspace_realloc_in_place(mspace msp, void* oldmem, size_t bytes) {
+  void* mem = 0;
+  if (oldmem != 0) {
+    if (bytes >= MAX_REQUEST) {
+      MALLOC_FAILURE_ACTION;
+    }
+    else {
+      size_t nb = request2size(bytes);
+      mchunkptr oldp = mem2chunk(oldmem);
+#if ! FOOTERS
+      mstate m = (mstate)msp;
+#else /* FOOTERS */
+      mstate m = get_mstate_for(oldp);
+      (void)msp; /* placate people compiling -Wunused */
+      if (!ok_magic(m)) {
+        USAGE_ERROR_ACTION(m, oldmem);
+        return 0;
+      }
+#endif /* FOOTERS */
+      if (!PREACTION(m)) {
+        mchunkptr newp = try_realloc_chunk(m, oldp, nb, 0);
+        POSTACTION(m);
+        if (newp == oldp) {
+          check_inuse_chunk(m, newp);
+          mem = oldmem;
+        }
+      }
+    }
+  }
+  return mem;
+}
+
+void* mspace_memalign(mspace msp, size_t alignment, size_t bytes) {
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  if (alignment <= MALLOC_ALIGNMENT)
+    return mspace_malloc(msp, bytes);
+  return internal_memalign(ms, alignment, bytes);
+}
+
+void** mspace_independent_calloc(mspace msp, size_t n_elements,
+                                 size_t elem_size, void* chunks[]) {
+  size_t sz = elem_size; /* serves as 1-element array */
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  return ialloc(ms, n_elements, &sz, 3, chunks);
+}
+
+void** mspace_independent_comalloc(mspace msp, size_t n_elements,
+                                   size_t sizes[], void* chunks[]) {
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+    return 0;
+  }
+  return ialloc(ms, n_elements, sizes, 0, chunks);
+}
+
+size_t mspace_bulk_free(mspace msp, void* array[], size_t nelem) {
+  return internal_bulk_free((mstate)msp, array, nelem);
+}
+
+#if MALLOC_INSPECT_ALL
+void mspace_inspect_all(mspace msp,
+                        void(*handler)(void *start,
+                                       void *end,
+                                       size_t used_bytes,
+                                       void* callback_arg),
+                        void* arg) {
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    if (!PREACTION(ms)) {
+      internal_inspect_all(ms, handler, arg);
+      POSTACTION(ms);
+    }
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+}
+#endif /* MALLOC_INSPECT_ALL */
+
+int mspace_trim(mspace msp, size_t pad) {
+  int result = 0;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    if (!PREACTION(ms)) {
+      result = sys_trim(ms, pad);
+      POSTACTION(ms);
+    }
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+#if !NO_MALLOC_STATS
+void mspace_malloc_stats(mspace msp) {
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    internal_malloc_stats(ms);
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+}
+#endif /* NO_MALLOC_STATS */
+
+size_t mspace_footprint(mspace msp) {
+  size_t result = 0;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    result = ms->footprint;
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+size_t mspace_max_footprint(mspace msp) {
+  size_t result = 0;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    result = ms->max_footprint;
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+size_t mspace_footprint_limit(mspace msp) {
+  size_t result = 0;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    size_t maf = ms->footprint_limit;
+    result = (maf == 0) ? MAX_SIZE_T : maf;
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+size_t mspace_set_footprint_limit(mspace msp, size_t bytes) {
+  size_t result = 0;
+  mstate ms = (mstate)msp;
+  if (ok_magic(ms)) {
+    if (bytes == 0)
+      result = granularity_align(1); /* Use minimal size */
+    if (bytes == MAX_SIZE_T)
+      result = 0;                    /* disable */
+    else
+      result = granularity_align(bytes);
+    ms->footprint_limit = result;
+  }
+  else {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return result;
+}
+
+#if !NO_MALLINFO
+struct mallinfo mspace_mallinfo(mspace msp) {
+  mstate ms = (mstate)msp;
+  if (!ok_magic(ms)) {
+    USAGE_ERROR_ACTION(ms,ms);
+  }
+  return internal_mallinfo(ms);
+}
+#endif /* NO_MALLINFO */
+
+size_t mspace_usable_size(const void* mem) {
+  if (mem != 0) {
+    mchunkptr p = mem2chunk(mem);
+    if (is_inuse(p))
+      return chunksize(p) - overhead_for(p);
+  }
+  return 0;
+}
+
+int mspace_mallopt(int param_number, int value) {
+  return change_mparam(param_number, value);
+}
+
+#endif /* MSPACES */
+
+
+/* -------------------- Alternative MORECORE functions ------------------- */
+
+/*
+  Guidelines for creating a custom version of MORECORE:
+
+  * For best performance, MORECORE should allocate in multiples of pagesize.
+  * MORECORE may allocate more memory than requested. (Or even less,
+      but this will usually result in a malloc failure.)
+  * MORECORE must not allocate memory when given argument zero, but
+      instead return one past the end address of memory from previous
+      nonzero call.
+  * For best performance, consecutive calls to MORECORE with positive
+      arguments should return increasing addresses, indicating that
+      space has been contiguously extended.
+  * Even though consecutive calls to MORECORE need not return contiguous
+      addresses, it must be OK for malloc'ed chunks to span multiple
+      regions in those cases where they do happen to be contiguous.
+  * MORECORE need not handle negative arguments -- it may instead
+      just return MFAIL when given negative arguments.
+      Negative arguments are always multiples of pagesize. MORECORE
+      must not misinterpret negative args as large positive unsigned
+      args. You can suppress all such calls from even occurring by defining
+      MORECORE_CANNOT_TRIM,
+
+  As an example alternative MORECORE, here is a custom allocator
+  kindly contributed for pre-OSX macOS.  It uses virtually but not
+  necessarily physically contiguous non-paged memory (locked in,
+  present and won't get swapped out).  You can use it by uncommenting
+  this section, adding some #includes, and setting up the appropriate
+  defines above:
+
+      #define MORECORE osMoreCore
+
+  There is also a shutdown routine that should somehow be called for
+  cleanup upon program exit.
+
+  #define MAX_POOL_ENTRIES 100
+  #define MINIMUM_MORECORE_SIZE  (64 * 1024U)
+  static int next_os_pool;
+  void *our_os_pools[MAX_POOL_ENTRIES];
+
+  void *osMoreCore(int size)
+  {
+    void *ptr = 0;
+    static void *sbrk_top = 0;
+
+    if (size > 0)
+    {
+      if (size < MINIMUM_MORECORE_SIZE)
+         size = MINIMUM_MORECORE_SIZE;
+      if (CurrentExecutionLevel() == kTaskLevel)
+         ptr = PoolAllocateResident(size + RM_PAGE_SIZE, 0);
+      if (ptr == 0)
+      {
+        return (void *) MFAIL;
+      }
+      // save ptrs so they can be freed during cleanup
+      our_os_pools[next_os_pool] = ptr;
+      next_os_pool++;
+      ptr = (void *) ((((size_t) ptr) + RM_PAGE_MASK) & ~RM_PAGE_MASK);
+      sbrk_top = (char *) ptr + size;
+      return ptr;
+    }
+    else if (size < 0)
+    {
+      // we don't currently support shrink behavior
+      return (void *) MFAIL;
+    }
+    else
+    {
+      return sbrk_top;
+    }
+  }
+
+  // cleanup any allocated memory pools
+  // called as last thing before shutting down driver
+
+  void osCleanupMem(void)
+  {
+    void **ptr;
+
+    for (ptr = our_os_pools; ptr < &our_os_pools[MAX_POOL_ENTRIES]; ptr++)
+      if (*ptr)
+      {
+         PoolDeallocate(*ptr);
+         *ptr = 0;
+      }
+  }
+
+*/
+
+
+/* -----------------------------------------------------------------------
+History:
+    v2.8.6 Wed Aug 29 06:57:58 2012  Doug Lea
+      * fix bad comparison in dlposix_memalign
+      * don't reuse adjusted asize in sys_alloc
+      * add LOCK_AT_FORK -- thanks to Kirill Artamonov for the suggestion
+      * reduce compiler warnings -- thanks to all who reported/suggested these
+
+    v2.8.5 Sun May 22 10:26:02 2011  Doug Lea  (dl at gee)
+      * Always perform unlink checks unless INSECURE
+      * Add posix_memalign.
+      * Improve realloc to expand in more cases; expose realloc_in_place.
+        Thanks to Peter Buhr for the suggestion.
+      * Add footprint_limit, inspect_all, bulk_free. Thanks
+        to Barry Hayes and others for the suggestions.
+      * Internal refactorings to avoid calls while holding locks
+      * Use non-reentrant locks by default. Thanks to Roland McGrath
+        for the suggestion.
+      * Small fixes to mspace_destroy, reset_on_error.
+      * Various configuration extensions/changes. Thanks
+         to all who contributed these.
+
+    V2.8.4a Thu Apr 28 14:39:43 2011 (dl at gee.cs.oswego.edu)
+      * Update Creative Commons URL
+
+    V2.8.4 Wed May 27 09:56:23 2009  Doug Lea  (dl at gee)
+      * Use zeros instead of prev foot for is_mmapped
+      * Add mspace_track_large_chunks; thanks to Jean Brouwers
+      * Fix set_inuse in internal_realloc; thanks to Jean Brouwers
+      * Fix insufficient sys_alloc padding when using 16byte alignment
+      * Fix bad error check in mspace_footprint
+      * Adaptations for ptmalloc; thanks to Wolfram Gloger.
+      * Reentrant spin locks; thanks to Earl Chew and others
+      * Win32 improvements; thanks to Niall Douglas and Earl Chew
+      * Add NO_SEGMENT_TRAVERSAL and MAX_RELEASE_CHECK_RATE options
+      * Extension hook in malloc_state
+      * Various small adjustments to reduce warnings on some compilers
+      * Various configuration extensions/changes for more platforms. Thanks
+         to all who contributed these.
+
+    V2.8.3 Thu Sep 22 11:16:32 2005  Doug Lea  (dl at gee)
+      * Add max_footprint functions
+      * Ensure all appropriate literals are size_t
+      * Fix conditional compilation problem for some #define settings
+      * Avoid concatenating segments with the one provided
+        in create_mspace_with_base
+      * Rename some variables to avoid compiler shadowing warnings
+      * Use explicit lock initialization.
+      * Better handling of sbrk interference.
+      * Simplify and fix segment insertion, trimming and mspace_destroy
+      * Reinstate REALLOC_ZERO_BYTES_FREES option from 2.7.x
+      * Thanks especially to Dennis Flanagan for help on these.
+
+    V2.8.2 Sun Jun 12 16:01:10 2005  Doug Lea  (dl at gee)
+      * Fix memalign brace error.
+
+    V2.8.1 Wed Jun  8 16:11:46 2005  Doug Lea  (dl at gee)
+      * Fix improper #endif nesting in C++
+      * Add explicit casts needed for C++
+
+    V2.8.0 Mon May 30 14:09:02 2005  Doug Lea  (dl at gee)
+      * Use trees for large bins
+      * Support mspaces
+      * Use segments to unify sbrk-based and mmap-based system allocation,
+        removing need for emulation on most platforms without sbrk.
+      * Default safety checks
+      * Optional footer checks. Thanks to William Robertson for the idea.
+      * Internal code refactoring
+      * Incorporate suggestions and platform-specific changes.
+        Thanks to Dennis Flanagan, Colin Plumb, Niall Douglas,
+        Aaron Bachmann,  Emery Berger, and others.
+      * Speed up non-fastbin processing enough to remove fastbins.
+      * Remove useless cfree() to avoid conflicts with other apps.
+      * Remove internal memcpy, memset. Compilers handle builtins better.
+      * Remove some options that no one ever used and rename others.
+
+    V2.7.2 Sat Aug 17 09:07:30 2002  Doug Lea  (dl at gee)
+      * Fix malloc_state bitmap array misdeclaration
+
+    V2.7.1 Thu Jul 25 10:58:03 2002  Doug Lea  (dl at gee)
+      * Allow tuning of FIRST_SORTED_BIN_SIZE
+      * Use PTR_UINT as type for all ptr->int casts. Thanks to John Belmonte.
+      * Better detection and support for non-contiguousness of MORECORE.
+        Thanks to Andreas Mueller, Conal Walsh, and Wolfram Gloger
+      * Bypass most of malloc if no frees. Thanks To Emery Berger.
+      * Fix freeing of old top non-contiguous chunk im sysmalloc.
+      * Raised default trim and map thresholds to 256K.
+      * Fix mmap-related #defines. Thanks to Lubos Lunak.
+      * Fix copy macros; added LACKS_FCNTL_H. Thanks to Neal Walfield.
+      * Branch-free bin calculation
+      * Default trim and mmap thresholds now 256K.
+
+    V2.7.0 Sun Mar 11 14:14:06 2001  Doug Lea  (dl at gee)
+      * Introduce independent_comalloc and independent_calloc.
+        Thanks to Michael Pachos for motivation and help.
+      * Make optional .h file available
+      * Allow > 2GB requests on 32bit systems.
+      * new WIN32 sbrk, mmap, munmap, lock code from <Walter@GeNeSys-e.de>.
+        Thanks also to Andreas Mueller <a.mueller at paradatec.de>,
+        and Anonymous.
+      * Allow override of MALLOC_ALIGNMENT (Thanks to Ruud Waij for
+        helping test this.)
+      * memalign: check alignment arg
+      * realloc: don't try to shift chunks backwards, since this
+        leads to  more fragmentation in some programs and doesn't
+        seem to help in any others.
+      * Collect all cases in malloc requiring system memory into sysmalloc
+      * Use mmap as backup to sbrk
+      * Place all internal state in malloc_state
+      * Introduce fastbins (although similar to 2.5.1)
+      * Many minor tunings and cosmetic improvements
+      * Introduce USE_PUBLIC_MALLOC_WRAPPERS, USE_MALLOC_LOCK
+      * Introduce MALLOC_FAILURE_ACTION, MORECORE_CONTIGUOUS
+        Thanks to Tony E. Bennett <tbennett@nvidia.com> and others.
+      * Include errno.h to support default failure action.
+
+    V2.6.6 Sun Dec  5 07:42:19 1999  Doug Lea  (dl at gee)
+      * return null for negative arguments
+      * Added Several WIN32 cleanups from Martin C. Fong <mcfong at yahoo.com>
+         * Add 'LACKS_SYS_PARAM_H' for those systems without 'sys/param.h'
+          (e.g. WIN32 platforms)
+         * Cleanup header file inclusion for WIN32 platforms
+         * Cleanup code to avoid Microsoft Visual C++ compiler complaints
+         * Add 'USE_DL_PREFIX' to quickly allow co-existence with existing
+           memory allocation routines
+         * Set 'malloc_getpagesize' for WIN32 platforms (needs more work)
+         * Use 'assert' rather than 'ASSERT' in WIN32 code to conform to
+           usage of 'assert' in non-WIN32 code
+         * Improve WIN32 'sbrk()' emulation's 'findRegion()' routine to
+           avoid infinite loop
+      * Always call 'fREe()' rather than 'free()'
+
+    V2.6.5 Wed Jun 17 15:57:31 1998  Doug Lea  (dl at gee)
+      * Fixed ordering problem with boundary-stamping
+
+    V2.6.3 Sun May 19 08:17:58 1996  Doug Lea  (dl at gee)
+      * Added pvalloc, as recommended by H.J. Liu
+      * Added 64bit pointer support mainly from Wolfram Gloger
+      * Added anonymously donated WIN32 sbrk emulation
+      * Malloc, calloc, getpagesize: add optimizations from Raymond Nijssen
+      * malloc_extend_top: fix mask error that caused wastage after
+        foreign sbrks
+      * Add linux mremap support code from HJ Liu
+
+    V2.6.2 Tue Dec  5 06:52:55 1995  Doug Lea  (dl at gee)
+      * Integrated most documentation with the code.
+      * Add support for mmap, with help from
+        Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
+      * Use last_remainder in more cases.
+      * Pack bins using idea from  colin@nyx10.cs.du.edu
+      * Use ordered bins instead of best-fit threshhold
+      * Eliminate block-local decls to simplify tracing and debugging.
+      * Support another case of realloc via move into top
+      * Fix error occuring when initial sbrk_base not word-aligned.
+      * Rely on page size for units instead of SBRK_UNIT to
+        avoid surprises about sbrk alignment conventions.
+      * Add mallinfo, mallopt. Thanks to Raymond Nijssen
+        (raymond@es.ele.tue.nl) for the suggestion.
+      * Add `pad' argument to malloc_trim and top_pad mallopt parameter.
+      * More precautions for cases where other routines call sbrk,
+        courtesy of Wolfram Gloger (Gloger@lrz.uni-muenchen.de).
+      * Added macros etc., allowing use in linux libc from
+        H.J. Lu (hjl@gnu.ai.mit.edu)
+      * Inverted this history list
+
+    V2.6.1 Sat Dec  2 14:10:57 1995  Doug Lea  (dl at gee)
+      * Re-tuned and fixed to behave more nicely with V2.6.0 changes.
+      * Removed all preallocation code since under current scheme
+        the work required to undo bad preallocations exceeds
+        the work saved in good cases for most test programs.
+      * No longer use return list or unconsolidated bins since
+        no scheme using them consistently outperforms those that don't
+        given above changes.
+      * Use best fit for very large chunks to prevent some worst-cases.
+      * Added some support for debugging
+
+    V2.6.0 Sat Nov  4 07:05:23 1995  Doug Lea  (dl at gee)
+      * Removed footers when chunks are in use. Thanks to
+        Paul Wilson (wilson@cs.texas.edu) for the suggestion.
+
+    V2.5.4 Wed Nov  1 07:54:51 1995  Doug Lea  (dl at gee)
+      * Added malloc_trim, with help from Wolfram Gloger
+        (wmglo@Dent.MED.Uni-Muenchen.DE).
+
+    V2.5.3 Tue Apr 26 10:16:01 1994  Doug Lea  (dl at g)
+
+    V2.5.2 Tue Apr  5 16:20:40 1994  Doug Lea  (dl at g)
+      * realloc: try to expand in both directions
+      * malloc: swap order of clean-bin strategy;
+      * realloc: only conditionally expand backwards
+      * Try not to scavenge used bins
+      * Use bin counts as a guide to preallocation
+      * Occasionally bin return list chunks in first scan
+      * Add a few optimizations from colin@nyx10.cs.du.edu
+
+    V2.5.1 Sat Aug 14 15:40:43 1993  Doug Lea  (dl at g)
+      * faster bin computation & slightly different binning
+      * merged all consolidations to one part of malloc proper
+         (eliminating old malloc_find_space & malloc_clean_bin)
+      * Scan 2 returns chunks (not just 1)
+      * Propagate failure in realloc if malloc returns 0
+      * Add stuff to allow compilation on non-ANSI compilers
+          from kpv@research.att.com
+
+    V2.5 Sat Aug  7 07:41:59 1993  Doug Lea  (dl at g.oswego.edu)
+      * removed potential for odd address access in prev_chunk
+      * removed dependency on getpagesize.h
+      * misc cosmetics and a bit more internal documentation
+      * anticosmetics: mangled names in macros to evade debugger strangeness
+      * tested on sparc, hp-700, dec-mips, rs6000
+          with gcc & native cc (hp, dec only) allowing
+          Detlefs & Zorn comparison study (in SIGPLAN Notices.)
+
+    Trial version Fri Aug 28 13:14:29 1992  Doug Lea  (dl at g.oswego.edu)
+      * Based loosely on libg++-1.2X malloc. (It retains some of the overall
+         structure of old version,  but most details differ.)
+
+*/
diff --git a/vendor/dlmalloc/src/dlmalloc.rs b/vendor/dlmalloc/src/dlmalloc.rs
new file mode 100644
index 000000000..a4b4b71b4
--- /dev/null
+++ b/vendor/dlmalloc/src/dlmalloc.rs
@@ -0,0 +1,1829 @@
+// This is a version of dlmalloc.c ported to Rust. You can find the original
+// source at ftp://g.oswego.edu/pub/misc/malloc.c
+//
+// The original source was written by Doug Lea and released to the public domain
+
+use core::cmp;
+use core::mem;
+use core::ptr;
+
+use Allocator;
+
+pub struct Dlmalloc<A> {
+    smallmap: u32,
+    treemap: u32,
+    smallbins: [*mut Chunk; (NSMALLBINS + 1) * 2],
+    treebins: [*mut TreeChunk; NTREEBINS],
+    dvsize: usize,
+    topsize: usize,
+    dv: *mut Chunk,
+    top: *mut Chunk,
+    footprint: usize,
+    max_footprint: usize,
+    seg: Segment,
+    trim_check: usize,
+    least_addr: *mut u8,
+    release_checks: usize,
+    system_allocator: A,
+}
+unsafe impl<A: Send> Send for Dlmalloc<A> {}
+
+// TODO: document this
+const NSMALLBINS: usize = 32;
+const NTREEBINS: usize = 32;
+const SMALLBIN_SHIFT: usize = 3;
+const TREEBIN_SHIFT: usize = 8;
+
+// TODO: runtime configurable? documentation?
+const DEFAULT_GRANULARITY: usize = 64 * 1024;
+const DEFAULT_TRIM_THRESHOLD: usize = 2 * 1024 * 1024;
+const MAX_RELEASE_CHECK_RATE: usize = 4095;
+
+#[repr(C)]
+struct Chunk {
+    prev_foot: usize,
+    head: usize,
+    prev: *mut Chunk,
+    next: *mut Chunk,
+}
+
+#[repr(C)]
+struct TreeChunk {
+    chunk: Chunk,
+    child: [*mut TreeChunk; 2],
+    parent: *mut TreeChunk,
+    index: u32,
+}
+
+#[repr(C)]
+#[derive(Clone, Copy)]
+struct Segment {
+    base: *mut u8,
+    size: usize,
+    next: *mut Segment,
+    flags: u32,
+}
+
+fn align_up(a: usize, alignment: usize) -> usize {
+    debug_assert!(alignment.is_power_of_two());
+    (a + (alignment - 1)) & !(alignment - 1)
+}
+
+fn left_bits(x: u32) -> u32 {
+    (x << 1) | (!(x << 1)).wrapping_add(1)
+}
+
+fn least_bit(x: u32) -> u32 {
+    x & (!x + 1)
+}
+
+fn leftshift_for_tree_index(x: u32) -> u32 {
+    let x = x as usize;
+    if x == NTREEBINS - 1 {
+        0
+    } else {
+        (mem::size_of::<usize>() * 8 - 1 - ((x >> 1) + TREEBIN_SHIFT - 2)) as u32
+    }
+}
+
+impl<A> Dlmalloc<A> {
+    pub const fn new(system_allocator: A) -> Dlmalloc<A> {
+        Dlmalloc {
+            smallmap: 0,
+            treemap: 0,
+            smallbins: [0 as *mut _; (NSMALLBINS + 1) * 2],
+            treebins: [0 as *mut _; NTREEBINS],
+            dvsize: 0,
+            topsize: 0,
+            dv: 0 as *mut _,
+            top: 0 as *mut _,
+            footprint: 0,
+            max_footprint: 0,
+            seg: Segment {
+                base: 0 as *mut _,
+                size: 0,
+                next: 0 as *mut _,
+                flags: 0,
+            },
+            trim_check: 0,
+            least_addr: 0 as *mut _,
+            release_checks: 0,
+            system_allocator,
+        }
+    }
+}
+
+impl<A: Allocator> Dlmalloc<A> {
+    // TODO: can we get rid of this?
+    pub fn malloc_alignment(&self) -> usize {
+        mem::size_of::<usize>() * 2
+    }
+
+    // TODO: dox
+    fn chunk_overhead(&self) -> usize {
+        mem::size_of::<usize>()
+    }
+
+    fn mmap_chunk_overhead(&self) -> usize {
+        2 * mem::size_of::<usize>()
+    }
+
+    // TODO: dox
+    fn min_large_size(&self) -> usize {
+        1 << TREEBIN_SHIFT
+    }
+
+    // TODO: dox
+    fn max_small_size(&self) -> usize {
+        self.min_large_size() - 1
+    }
+
+    // TODO: dox
+    fn max_small_request(&self) -> usize {
+        self.max_small_size() - (self.malloc_alignment() - 1) - self.chunk_overhead()
+    }
+
+    // TODO: dox
+    fn min_chunk_size(&self) -> usize {
+        align_up(mem::size_of::<Chunk>(), self.malloc_alignment())
+    }
+
+    // TODO: dox
+    fn min_request(&self) -> usize {
+        self.min_chunk_size() - self.chunk_overhead() - 1
+    }
+
+    // TODO: dox
+    fn max_request(&self) -> usize {
+        // min_sys_alloc_space: the largest `X` such that
+        //   pad_request(X - 1)        -- minus 1, because requests of exactly
+        //                                `max_request` will not be honored
+        //   + self.top_foot_size()
+        //   + self.malloc_alignment()
+        //   + DEFAULT_GRANULARITY
+        // ==
+        //   usize::MAX
+        let min_sys_alloc_space =
+            ((!0 - (DEFAULT_GRANULARITY + self.top_foot_size() + self.malloc_alignment()) + 1)
+                & !self.malloc_alignment())
+                - self.chunk_overhead()
+                + 1;
+
+        cmp::min((!self.min_chunk_size() + 1) << 2, min_sys_alloc_space)
+    }
+
+    fn pad_request(&self, amt: usize) -> usize {
+        align_up(amt + self.chunk_overhead(), self.malloc_alignment())
+    }
+
+    fn small_index(&self, size: usize) -> u32 {
+        (size >> SMALLBIN_SHIFT) as u32
+    }
+
+    fn small_index2size(&self, idx: u32) -> usize {
+        (idx as usize) << SMALLBIN_SHIFT
+    }
+
+    fn is_small(&self, s: usize) -> bool {
+        s >> SMALLBIN_SHIFT < NSMALLBINS
+    }
+
+    fn is_aligned(&self, a: usize) -> bool {
+        a & (self.malloc_alignment() - 1) == 0
+    }
+
+    fn align_offset(&self, addr: *mut u8) -> usize {
+        self.align_offset_usize(addr as usize)
+    }
+
+    fn align_offset_usize(&self, addr: usize) -> usize {
+        align_up(addr, self.malloc_alignment()) - (addr as usize)
+    }
+
+    fn top_foot_size(&self) -> usize {
+        self.align_offset_usize(Chunk::mem_offset() as usize)
+            + self.pad_request(mem::size_of::<Segment>())
+            + self.min_chunk_size()
+    }
+
+    fn mmap_foot_pad(&self) -> usize {
+        4 * mem::size_of::<usize>()
+    }
+
+    fn align_as_chunk(&self, ptr: *mut u8) -> *mut Chunk {
+        unsafe {
+            let chunk = Chunk::to_mem(ptr as *mut Chunk);
+            ptr.offset(self.align_offset(chunk) as isize) as *mut Chunk
+        }
+    }
+
+    fn request2size(&self, req: usize) -> usize {
+        if req < self.min_request() {
+            self.min_chunk_size()
+        } else {
+            self.pad_request(req)
+        }
+    }
+
+    unsafe fn overhead_for(&self, p: *mut Chunk) -> usize {
+        if Chunk::mmapped(p) {
+            self.mmap_chunk_overhead()
+        } else {
+            self.chunk_overhead()
+        }
+    }
+
+    pub unsafe fn calloc_must_clear(&self, ptr: *mut u8) -> bool {
+        !self.system_allocator.allocates_zeros() || !Chunk::mmapped(Chunk::from_mem(ptr))
+    }
+
+    pub unsafe fn malloc(&mut self, size: usize) -> *mut u8 {
+        self.check_malloc_state();
+
+        let nb;
+        if size <= self.max_small_request() {
+            nb = self.request2size(size);
+            let mut idx = self.small_index(nb);
+            let smallbits = self.smallmap >> idx;
+
+            // Check the bin for `idx` (the lowest bit) but also check the next
+            // bin up to use that to satisfy our request, if needed.
+            if smallbits & 0b11 != 0 {
+                // If our the lowest bit, our `idx`, is unset then bump up the
+                // index as we'll be using the next bucket up.
+                idx += !smallbits & 1;
+
+                let b = self.smallbin_at(idx);
+                let p = (*b).prev;
+                self.unlink_first_small_chunk(b, p, idx);
+                let smallsize = self.small_index2size(idx);
+                Chunk::set_inuse_and_pinuse(p, smallsize);
+                let ret = Chunk::to_mem(p);
+                self.check_malloced_chunk(ret, nb);
+                return ret;
+            }
+
+            if nb > self.dvsize {
+                // If there's some other bin with some memory, then we just use
+                // the next smallest bin
+                if smallbits != 0 {
+                    let leftbits = (smallbits << idx) & left_bits(1 << idx);
+                    let leastbit = least_bit(leftbits);
+                    let i = leastbit.trailing_zeros();
+                    let b = self.smallbin_at(i);
+                    let p = (*b).prev;
+                    debug_assert_eq!(Chunk::size(p), self.small_index2size(i));
+                    self.unlink_first_small_chunk(b, p, i);
+                    let smallsize = self.small_index2size(i);
+                    let rsize = smallsize - nb;
+                    if mem::size_of::<usize>() != 4 && rsize < self.min_chunk_size() {
+                        Chunk::set_inuse_and_pinuse(p, smallsize);
+                    } else {
+                        Chunk::set_size_and_pinuse_of_inuse_chunk(p, nb);
+                        let r = Chunk::plus_offset(p, nb);
+                        Chunk::set_size_and_pinuse_of_free_chunk(r, rsize);
+                        self.replace_dv(r, rsize);
+                    }
+                    let ret = Chunk::to_mem(p);
+                    self.check_malloced_chunk(ret, nb);
+                    return ret;
+                } else if self.treemap != 0 {
+                    let mem = self.tmalloc_small(nb);
+                    if !mem.is_null() {
+                        self.check_malloced_chunk(mem, nb);
+                        self.check_malloc_state();
+                        return mem;
+                    }
+                }
+            }
+        } else if size >= self.max_request() {
+            // TODO: translate this to unsupported
+            return ptr::null_mut();
+        } else {
+            nb = self.pad_request(size);
+            if self.treemap != 0 {
+                let mem = self.tmalloc_large(nb);
+                if !mem.is_null() {
+                    self.check_malloced_chunk(mem, nb);
+                    self.check_malloc_state();
+                    return mem;
+                }
+            }
+        }
+
+        // use the `dv` node if we can, splitting it if necessary or otherwise
+        // exhausting the entire chunk
+        if nb <= self.dvsize {
+            let rsize = self.dvsize - nb;
+            let p = self.dv;
+            if rsize >= self.min_chunk_size() {
+                self.dv = Chunk::plus_offset(p, nb);
+                self.dvsize = rsize;
+                let r = self.dv;
+                Chunk::set_size_and_pinuse_of_free_chunk(r, rsize);
+                Chunk::set_size_and_pinuse_of_inuse_chunk(p, nb);
+            } else {
+                let dvs = self.dvsize;
+                self.dvsize = 0;
+                self.dv = ptr::null_mut();
+                Chunk::set_inuse_and_pinuse(p, dvs);
+            }
+            let ret = Chunk::to_mem(p);
+            self.check_malloced_chunk(ret, nb);
+            self.check_malloc_state();
+            return ret;
+        }
+
+        // Split the top node if we can
+        if nb < self.topsize {
+            self.topsize -= nb;
+            let rsize = self.topsize;
+            let p = self.top;
+            self.top = Chunk::plus_offset(p, nb);
+            let r = self.top;
+            (*r).head = rsize | PINUSE;
+            Chunk::set_size_and_pinuse_of_inuse_chunk(p, nb);
+            self.check_top_chunk(self.top);
+            let ret = Chunk::to_mem(p);
+            self.check_malloced_chunk(ret, nb);
+            self.check_malloc_state();
+            return ret;
+        }
+
+        self.sys_alloc(nb)
+    }
+
+    /// allocates system resources
+    unsafe fn sys_alloc(&mut self, size: usize) -> *mut u8 {
+        self.check_malloc_state();
+        // keep in sync with max_request
+        let asize = align_up(
+            size + self.top_foot_size() + self.malloc_alignment(),
+            DEFAULT_GRANULARITY,
+        );
+
+        let (tbase, tsize, flags) = self.system_allocator.alloc(asize);
+        if tbase.is_null() {
+            return tbase;
+        }
+
+        self.footprint += tsize;
+        self.max_footprint = cmp::max(self.max_footprint, self.footprint);
+
+        if self.top.is_null() {
+            if self.least_addr.is_null() || tbase < self.least_addr {
+                self.least_addr = tbase;
+            }
+            self.seg.base = tbase;
+            self.seg.size = tsize;
+            self.seg.flags = flags;
+            self.release_checks = MAX_RELEASE_CHECK_RATE;
+            self.init_bins();
+            let tsize = tsize - self.top_foot_size();
+            self.init_top(tbase as *mut Chunk, tsize);
+        // let mn = Chunk::next(Chunk::from_mem(self as *mut _ as *mut u8));
+        // let top_foot_size = self.top_foot_size();
+        // self.init_top(mn, tbase as usize + tsize - mn as usize - top_foot_size);
+        } else {
+            let mut sp = &mut self.seg as *mut Segment;
+            while !sp.is_null() && tbase != Segment::top(sp) {
+                sp = (*sp).next;
+            }
+            if !sp.is_null()
+                && !Segment::is_extern(sp)
+                && Segment::sys_flags(sp) == flags
+                && Segment::holds(sp, self.top as *mut u8)
+            {
+                (*sp).size += tsize;
+                let ptr = self.top;
+                let size = self.topsize + tsize;
+                self.init_top(ptr, size);
+            } else {
+                self.least_addr = cmp::min(tbase, self.least_addr);
+                let mut sp = &mut self.seg as *mut Segment;
+                while !sp.is_null() && (*sp).base != tbase.offset(tsize as isize) {
+                    sp = (*sp).next;
+                }
+                if !sp.is_null() && !Segment::is_extern(sp) && Segment::sys_flags(sp) == flags {
+                    let oldbase = (*sp).base;
+                    (*sp).base = tbase;
+                    (*sp).size += tsize;
+                    return self.prepend_alloc(tbase, oldbase, size);
+                } else {
+                    self.add_segment(tbase, tsize, flags);
+                }
+            }
+        }
+
+        if size < self.topsize {
+            self.topsize -= size;
+            let rsize = self.topsize;
+            let p = self.top;
+            self.top = Chunk::plus_offset(p, size);
+            let r = self.top;
+            (*r).head = rsize | PINUSE;
+            Chunk::set_size_and_pinuse_of_inuse_chunk(p, size);
+            let ret = Chunk::to_mem(p);
+            self.check_top_chunk(self.top);
+            self.check_malloced_chunk(ret, size);
+            self.check_malloc_state();
+            return ret;
+        }
+
+        return ptr::null_mut();
+    }
+
+    pub unsafe fn realloc(&mut self, oldmem: *mut u8, bytes: usize) -> *mut u8 {
+        if bytes >= self.max_request() {
+            return ptr::null_mut();
+        }
+        let nb = self.request2size(bytes);
+        let oldp = Chunk::from_mem(oldmem);
+        let newp = self.try_realloc_chunk(oldp, nb, true);
+        if !newp.is_null() {
+            self.check_inuse_chunk(newp);
+            return Chunk::to_mem(newp);
+        }
+        let ptr = self.malloc(bytes);
+        if !ptr.is_null() {
+            let oc = Chunk::size(oldp) - self.overhead_for(oldp);
+            ptr::copy_nonoverlapping(oldmem, ptr, cmp::min(oc, bytes));
+            self.free(oldmem);
+        }
+        return ptr;
+    }
+
+    unsafe fn try_realloc_chunk(&mut self, p: *mut Chunk, nb: usize, can_move: bool) -> *mut Chunk {
+        let oldsize = Chunk::size(p);
+        let next = Chunk::plus_offset(p, oldsize);
+
+        if Chunk::mmapped(p) {
+            self.mmap_resize(p, nb, can_move)
+        } else if oldsize >= nb {
+            let rsize = oldsize - nb;
+            if rsize >= self.min_chunk_size() {
+                let r = Chunk::plus_offset(p, nb);
+                Chunk::set_inuse(p, nb);
+                Chunk::set_inuse(r, rsize);
+                self.dispose_chunk(r, rsize);
+            }
+            p
+        } else if next == self.top {
+            // extend into top
+            if oldsize + self.topsize <= nb {
+                return ptr::null_mut();
+            }
+            let newsize = oldsize + self.topsize;
+            let newtopsize = newsize - nb;
+            let newtop = Chunk::plus_offset(p, nb);
+            Chunk::set_inuse(p, nb);
+            (*newtop).head = newtopsize | PINUSE;
+            self.top = newtop;
+            self.topsize = newtopsize;
+            p
+        } else if next == self.dv {
+            // extend into dv
+            let dvs = self.dvsize;
+            if oldsize + dvs < nb {
+                return ptr::null_mut();
+            }
+            let dsize = oldsize + dvs - nb;
+            if dsize >= self.min_chunk_size() {
+                let r = Chunk::plus_offset(p, nb);
+                let n = Chunk::plus_offset(r, dsize);
+                Chunk::set_inuse(p, nb);
+                Chunk::set_size_and_pinuse_of_free_chunk(r, dsize);
+                Chunk::clear_pinuse(n);
+                self.dvsize = dsize;
+                self.dv = r;
+            } else {
+                // exhaust dv
+                let newsize = oldsize + dvs;
+                Chunk::set_inuse(p, newsize);
+                self.dvsize = 0;
+                self.dv = ptr::null_mut();
+            }
+            return p;
+        } else if !Chunk::cinuse(next) {
+            // extend into the next free chunk
+            let nextsize = Chunk::size(next);
+            if oldsize + nextsize < nb {
+                return ptr::null_mut();
+            }
+            let rsize = oldsize + nextsize - nb;
+            self.unlink_chunk(next, nextsize);
+            if rsize < self.min_chunk_size() {
+                let newsize = oldsize + nextsize;
+                Chunk::set_inuse(p, newsize);
+            } else {
+                let r = Chunk::plus_offset(p, nb);
+                Chunk::set_inuse(p, nb);
+                Chunk::set_inuse(r, rsize);
+                self.dispose_chunk(r, rsize);
+            }
+            p
+        } else {
+            ptr::null_mut()
+        }
+    }
+
+    unsafe fn mmap_resize(&mut self, oldp: *mut Chunk, nb: usize, can_move: bool) -> *mut Chunk {
+        let oldsize = Chunk::size(oldp);
+        // Can't shrink mmap regions below a small size
+        if self.is_small(nb) {
+            return ptr::null_mut();
+        }
+
+        // Keep the old chunk if it's big enough but not too big
+        if oldsize >= nb + mem::size_of::<usize>() && (oldsize - nb) <= (DEFAULT_GRANULARITY << 1) {
+            return oldp;
+        }
+
+        let offset = (*oldp).prev_foot;
+        let oldmmsize = oldsize + offset + self.mmap_foot_pad();
+        let newmmsize =
+            self.mmap_align(nb + 6 * mem::size_of::<usize>() + self.malloc_alignment() - 1);
+        let ptr = self.system_allocator.remap(
+            (oldp as *mut u8).offset(-(offset as isize)),
+            oldmmsize,
+            newmmsize,
+            can_move,
+        );
+        if ptr.is_null() {
+            return ptr::null_mut();
+        }
+        let newp = ptr.offset(offset as isize) as *mut Chunk;
+        let psize = newmmsize - offset - self.mmap_foot_pad();
+        (*newp).head = psize;
+        (*Chunk::plus_offset(newp, psize)).head = Chunk::fencepost_head();
+        (*Chunk::plus_offset(newp, psize + mem::size_of::<usize>())).head = 0;
+        self.least_addr = cmp::min(ptr, self.least_addr);
+        self.footprint = self.footprint + newmmsize - oldmmsize;
+        self.max_footprint = cmp::max(self.max_footprint, self.footprint);
+        self.check_mmapped_chunk(newp);
+        return newp;
+    }
+
+    fn mmap_align(&self, a: usize) -> usize {
+        align_up(a, self.system_allocator.page_size())
+    }
+
+    // Only call this with power-of-two alignment and alignment >
+    // `self.malloc_alignment()`
+    pub unsafe fn memalign(&mut self, mut alignment: usize, bytes: usize) -> *mut u8 {
+        if alignment < self.min_chunk_size() {
+            alignment = self.min_chunk_size();
+        }
+        if bytes >= self.max_request() - alignment {
+            return ptr::null_mut();
+        }
+        let nb = self.request2size(bytes);
+        let req = nb + alignment + self.min_chunk_size() - self.chunk_overhead();
+        let mem = self.malloc(req);
+        if mem.is_null() {
+            return mem;
+        }
+        let mut p = Chunk::from_mem(mem);
+        if mem as usize & (alignment - 1) != 0 {
+            // Here we find an aligned sopt inside the chunk. Since we need to
+            // give back leading space in a chunk of at least `min_chunk_size`,
+            // if the first calculation places us at a spot with less than
+            // `min_chunk_size` leader we can move to the next aligned spot.
+            // we've allocated enough total room so that this is always possible
+            let br =
+                Chunk::from_mem(((mem as usize + alignment - 1) & (!alignment + 1)) as *mut u8);
+            let pos = if (br as usize - p as usize) > self.min_chunk_size() {
+                br as *mut u8
+            } else {
+                (br as *mut u8).offset(alignment as isize)
+            };
+            let newp = pos as *mut Chunk;
+            let leadsize = pos as usize - p as usize;
+            let newsize = Chunk::size(p) - leadsize;
+
+            // for mmapped chunks just adjust the offset
+            if Chunk::mmapped(p) {
+                (*newp).prev_foot = (*p).prev_foot + leadsize;
+                (*newp).head = newsize;
+            } else {
+                // give back the leader, use the rest
+                Chunk::set_inuse(newp, newsize);
+                Chunk::set_inuse(p, leadsize);
+                self.dispose_chunk(p, leadsize);
+            }
+            p = newp;
+        }
+
+        // give back spare room at the end
+        if !Chunk::mmapped(p) {
+            let size = Chunk::size(p);
+            if size > nb + self.min_chunk_size() {
+                let remainder_size = size - nb;
+                let remainder = Chunk::plus_offset(p, nb);
+                Chunk::set_inuse(p, nb);
+                Chunk::set_inuse(remainder, remainder_size);
+                self.dispose_chunk(remainder, remainder_size);
+            }
+        }
+
+        let mem = Chunk::to_mem(p);
+        debug_assert!(Chunk::size(p) >= nb);
+        debug_assert_eq!(align_up(mem as usize, alignment), mem as usize);
+        self.check_inuse_chunk(p);
+        return mem;
+    }
+
+    // consolidate and bin a chunk, differs from exported versions of free
+    // mainly in that the chunk need not be marked as inuse
+    unsafe fn dispose_chunk(&mut self, mut p: *mut Chunk, mut psize: usize) {
+        let next = Chunk::plus_offset(p, psize);
+        if !Chunk::pinuse(p) {
+            let prevsize = (*p).prev_foot;
+            if Chunk::mmapped(p) {
+                psize += prevsize + self.mmap_foot_pad();
+                if self
+                    .system_allocator
+                    .free((p as *mut u8).offset(-(prevsize as isize)), psize)
+                {
+                    self.footprint -= psize;
+                }
+                return;
+            }
+            let prev = Chunk::minus_offset(p, prevsize);
+            psize += prevsize;
+            p = prev;
+            if p != self.dv {
+                self.unlink_chunk(p, prevsize);
+            } else if (*next).head & INUSE == INUSE {
+                self.dvsize = psize;
+                Chunk::set_free_with_pinuse(p, psize, next);
+                return;
+            }
+        }
+
+        if !Chunk::cinuse(next) {
+            // consolidate forward
+            if next == self.top {
+                self.topsize += psize;
+                let tsize = self.topsize;
+                self.top = p;
+                (*p).head = tsize | PINUSE;
+                if p == self.dv {
+                    self.dv = ptr::null_mut();
+                    self.dvsize = 0;
+                }
+                return;
+            } else if next == self.dv {
+                self.dvsize += psize;
+                let dsize = self.dvsize;
+                self.dv = p;
+                Chunk::set_size_and_pinuse_of_free_chunk(p, dsize);
+                return;
+            } else {
+                let nsize = Chunk::size(next);
+                psize += nsize;
+                self.unlink_chunk(next, nsize);
+                Chunk::set_size_and_pinuse_of_free_chunk(p, psize);
+                if p == self.dv {
+                    self.dvsize = psize;
+                    return;
+                }
+            }
+        } else {
+            Chunk::set_free_with_pinuse(p, psize, next);
+        }
+        self.insert_chunk(p, psize);
+    }
+
+    unsafe fn init_top(&mut self, ptr: *mut Chunk, size: usize) {
+        let offset = self.align_offset(Chunk::to_mem(ptr));
+        let p = Chunk::plus_offset(ptr, offset);
+        let size = size - offset;
+
+        self.top = p;
+        self.topsize = size;
+        (*p).head = size | PINUSE;
+        (*Chunk::plus_offset(p, size)).head = self.top_foot_size();
+        self.trim_check = DEFAULT_TRIM_THRESHOLD;
+    }
+
+    unsafe fn init_bins(&mut self) {
+        for i in 0..NSMALLBINS as u32 {
+            let bin = self.smallbin_at(i);
+            (*bin).next = bin;
+            (*bin).prev = bin;
+        }
+    }
+
+    unsafe fn prepend_alloc(&mut self, newbase: *mut u8, oldbase: *mut u8, size: usize) -> *mut u8 {
+        let p = self.align_as_chunk(newbase);
+        let mut oldfirst = self.align_as_chunk(oldbase);
+        let psize = oldfirst as usize - p as usize;
+        let q = Chunk::plus_offset(p, size);
+        let mut qsize = psize - size;
+        Chunk::set_size_and_pinuse_of_inuse_chunk(p, size);
+
+        debug_assert!(oldfirst > q);
+        debug_assert!(Chunk::pinuse(oldfirst));
+        debug_assert!(qsize >= self.min_chunk_size());
+
+        // consolidate the remainder with the first chunk of the old base
+        if oldfirst == self.top {
+            self.topsize += qsize;
+            let tsize = self.topsize;
+            self.top = q;
+            (*q).head = tsize | PINUSE;
+            self.check_top_chunk(q);
+        } else if oldfirst == self.dv {
+            self.dvsize += qsize;
+            let dsize = self.dvsize;
+            self.dv = q;
+            Chunk::set_size_and_pinuse_of_free_chunk(q, dsize);
+        } else {
+            if !Chunk::inuse(oldfirst) {
+                let nsize = Chunk::size(oldfirst);
+                self.unlink_chunk(oldfirst, nsize);
+                oldfirst = Chunk::plus_offset(oldfirst, nsize);
+                qsize += nsize;
+            }
+            Chunk::set_free_with_pinuse(q, qsize, oldfirst);
+            self.insert_chunk(q, qsize);
+            self.check_free_chunk(q);
+        }
+
+        let ret = Chunk::to_mem(p);
+        self.check_malloced_chunk(ret, size);
+        self.check_malloc_state();
+        return ret;
+    }
+
+    // add a segment to hold a new noncontiguous region
+    unsafe fn add_segment(&mut self, tbase: *mut u8, tsize: usize, flags: u32) {
+        // TODO: what in the world is this function doing
+
+        // Determine locations and sizes of segment, fenceposts, and the old top
+        let old_top = self.top as *mut u8;
+        let oldsp = self.segment_holding(old_top);
+        let old_end = Segment::top(oldsp);
+        let ssize = self.pad_request(mem::size_of::<Segment>());
+        let offset = ssize + mem::size_of::<usize>() * 4 + self.malloc_alignment() - 1;
+        let rawsp = old_end.offset(-(offset as isize));
+        let offset = self.align_offset(Chunk::to_mem(rawsp as *mut Chunk));
+        let asp = rawsp.offset(offset as isize);
+        let csp = if asp < old_top.offset(self.min_chunk_size() as isize) {
+            old_top
+        } else {
+            asp
+        };
+        let sp = csp as *mut Chunk;
+        let ss = Chunk::to_mem(sp) as *mut Segment;
+        let tnext = Chunk::plus_offset(sp, ssize);
+        let mut p = tnext;
+        let mut nfences = 0;
+
+        // reset the top to our new space
+        let size = tsize - self.top_foot_size();
+        self.init_top(tbase as *mut Chunk, size);
+
+        // set up our segment record
+        debug_assert!(self.is_aligned(ss as usize));
+        Chunk::set_size_and_pinuse_of_inuse_chunk(sp, ssize);
+        *ss = self.seg; // push our current record
+        self.seg.base = tbase;
+        self.seg.size = tsize;
+        self.seg.flags = flags;
+        self.seg.next = ss;
+
+        // insert trailing fences
+        loop {
+            let nextp = Chunk::plus_offset(p, mem::size_of::<usize>());
+            (*p).head = Chunk::fencepost_head();
+            nfences += 1;
+            if (&(*nextp).head as *const usize as *mut u8) < old_end {
+                p = nextp;
+            } else {
+                break;
+            }
+        }
+        debug_assert!(nfences >= 2);
+
+        // insert the rest of the old top into a bin as an ordinary free chunk
+        if csp != old_top {
+            let q = old_top as *mut Chunk;
+            let psize = csp as usize - old_top as usize;
+            let tn = Chunk::plus_offset(q, psize);
+            Chunk::set_free_with_pinuse(q, psize, tn);
+            self.insert_chunk(q, psize);
+        }
+
+        self.check_top_chunk(self.top);
+        self.check_malloc_state();
+    }
+
+    unsafe fn segment_holding(&self, ptr: *mut u8) -> *mut Segment {
+        let mut sp = &self.seg as *const Segment as *mut Segment;
+        while !sp.is_null() {
+            if (*sp).base <= ptr && ptr < Segment::top(sp) {
+                return sp;
+            }
+            sp = (*sp).next;
+        }
+        ptr::null_mut()
+    }
+
+    unsafe fn tmalloc_small(&mut self, size: usize) -> *mut u8 {
+        let leastbit = least_bit(self.treemap);
+        let i = leastbit.trailing_zeros();
+        let mut v = *self.treebin_at(i);
+        let mut t = v;
+        let mut rsize = Chunk::size(TreeChunk::chunk(t)) - size;
+
+        loop {
+            t = TreeChunk::leftmost_child(t);
+            if t.is_null() {
+                break;
+            }
+            let trem = Chunk::size(TreeChunk::chunk(t)) - size;
+            if trem < rsize {
+                rsize = trem;
+                v = t;
+            }
+        }
+
+        let vc = TreeChunk::chunk(v);
+        let r = Chunk::plus_offset(vc, size) as *mut TreeChunk;
+        debug_assert_eq!(Chunk::size(vc), rsize + size);
+        self.unlink_large_chunk(v);
+        if rsize < self.min_chunk_size() {
+            Chunk::set_inuse_and_pinuse(vc, rsize + size);
+        } else {
+            let rc = TreeChunk::chunk(r);
+            Chunk::set_size_and_pinuse_of_inuse_chunk(vc, size);
+            Chunk::set_size_and_pinuse_of_free_chunk(rc, rsize);
+            self.replace_dv(rc, rsize);
+        }
+        Chunk::to_mem(vc)
+    }
+
+    unsafe fn tmalloc_large(&mut self, size: usize) -> *mut u8 {
+        let mut v = ptr::null_mut();
+        let mut rsize = !size + 1;
+        let idx = self.compute_tree_index(size);
+        let mut t = *self.treebin_at(idx);
+        if !t.is_null() {
+            // Traverse thre tree for this bin looking for a node with size
+            // equal to the `size` above.
+            let mut sizebits = size << leftshift_for_tree_index(idx);
+            // Keep track of the deepest untaken right subtree
+            let mut rst = ptr::null_mut();
+            loop {
+                let csize = Chunk::size(TreeChunk::chunk(t));
+                if csize >= size && csize - size < rsize {
+                    v = t;
+                    rsize = csize - size;
+                    if rsize == 0 {
+                        break;
+                    }
+                }
+                let rt = (*t).child[1];
+                t = (*t).child[(sizebits >> (mem::size_of::<usize>() * 8 - 1)) & 1];
+                if !rt.is_null() && rt != t {
+                    rst = rt;
+                }
+                if t.is_null() {
+                    // Reset `t` to the least subtree holding sizes greater than
+                    // the `size` above, breaking out
+                    t = rst;
+                    break;
+                }
+                sizebits <<= 1;
+            }
+        }
+
+        // Set t to the root of the next non-empty treebin
+        if t.is_null() && v.is_null() {
+            let leftbits = left_bits(1 << idx) & self.treemap;
+            if leftbits != 0 {
+                let leastbit = least_bit(leftbits);
+                let i = leastbit.trailing_zeros();
+                t = *self.treebin_at(i);
+            }
+        }
+
+        // Find the smallest of this tree or subtree
+        while !t.is_null() {
+            let csize = Chunk::size(TreeChunk::chunk(t));
+            if csize >= size && csize - size < rsize {
+                rsize = csize - size;
+                v = t;
+            }
+            t = TreeChunk::leftmost_child(t);
+        }
+
+        // If dv is a better fit, then return null so malloc will use it
+        if v.is_null() || (self.dvsize >= size && !(rsize < self.dvsize - size)) {
+            return ptr::null_mut();
+        }
+
+        let vc = TreeChunk::chunk(v);
+        let r = Chunk::plus_offset(vc, size);
+        debug_assert_eq!(Chunk::size(vc), rsize + size);
+        self.unlink_large_chunk(v);
+        if rsize < self.min_chunk_size() {
+            Chunk::set_inuse_and_pinuse(vc, rsize + size);
+        } else {
+            Chunk::set_size_and_pinuse_of_inuse_chunk(vc, size);
+            Chunk::set_size_and_pinuse_of_free_chunk(r, rsize);
+            self.insert_chunk(r, rsize);
+        }
+        Chunk::to_mem(vc)
+    }
+
+    unsafe fn smallbin_at(&mut self, idx: u32) -> *mut Chunk {
+        debug_assert!(((idx * 2) as usize) < self.smallbins.len());
+        &mut *self.smallbins.get_unchecked_mut((idx as usize) * 2) as *mut *mut Chunk as *mut Chunk
+    }
+
+    unsafe fn treebin_at(&mut self, idx: u32) -> *mut *mut TreeChunk {
+        debug_assert!((idx as usize) < self.treebins.len());
+        &mut *self.treebins.get_unchecked_mut(idx as usize)
+    }
+
+    fn compute_tree_index(&self, size: usize) -> u32 {
+        let x = size >> TREEBIN_SHIFT;
+        if x == 0 {
+            0
+        } else if x > 0xffff {
+            NTREEBINS as u32 - 1
+        } else {
+            let k = mem::size_of_val(&x) * 8 - 1 - (x.leading_zeros() as usize);
+            ((k << 1) + (size >> (k + TREEBIN_SHIFT - 1) & 1)) as u32
+        }
+    }
+
+    unsafe fn unlink_first_small_chunk(&mut self, head: *mut Chunk, next: *mut Chunk, idx: u32) {
+        let ptr = (*next).prev;
+        debug_assert!(next != head);
+        debug_assert!(next != ptr);
+        debug_assert_eq!(Chunk::size(next), self.small_index2size(idx));
+        if head == ptr {
+            self.clear_smallmap(idx);
+        } else {
+            (*ptr).next = head;
+            (*head).prev = ptr;
+        }
+    }
+
+    unsafe fn replace_dv(&mut self, chunk: *mut Chunk, size: usize) {
+        let dvs = self.dvsize;
+        debug_assert!(self.is_small(dvs));
+        if dvs != 0 {
+            let dv = self.dv;
+            self.insert_small_chunk(dv, dvs);
+        }
+        self.dvsize = size;
+        self.dv = chunk;
+    }
+
+    unsafe fn insert_chunk(&mut self, chunk: *mut Chunk, size: usize) {
+        if self.is_small(size) {
+            self.insert_small_chunk(chunk, size);
+        } else {
+            self.insert_large_chunk(chunk as *mut TreeChunk, size);
+        }
+    }
+
+    unsafe fn insert_small_chunk(&mut self, chunk: *mut Chunk, size: usize) {
+        let idx = self.small_index(size);
+        let head = self.smallbin_at(idx);
+        let mut f = head;
+        debug_assert!(size >= self.min_chunk_size());
+        if !self.smallmap_is_marked(idx) {
+            self.mark_smallmap(idx);
+        } else {
+            f = (*head).prev;
+        }
+
+        (*head).prev = chunk;
+        (*f).next = chunk;
+        (*chunk).prev = f;
+        (*chunk).next = head;
+    }
+
+    unsafe fn insert_large_chunk(&mut self, chunk: *mut TreeChunk, size: usize) {
+        let idx = self.compute_tree_index(size);
+        let h = self.treebin_at(idx);
+        (*chunk).index = idx;
+        (*chunk).child[0] = ptr::null_mut();
+        (*chunk).child[1] = ptr::null_mut();
+        let chunkc = TreeChunk::chunk(chunk);
+        if !self.treemap_is_marked(idx) {
+            self.mark_treemap(idx);
+            *h = chunk;
+            (*chunk).parent = h as *mut TreeChunk; // TODO: dubious?
+            (*chunkc).next = chunkc;
+            (*chunkc).prev = chunkc;
+        } else {
+            let mut t = *h;
+            let mut k = size << leftshift_for_tree_index(idx);
+            loop {
+                if Chunk::size(TreeChunk::chunk(t)) != size {
+                    let c = &mut (*t).child[(k >> mem::size_of::<usize>() * 8 - 1) & 1];
+                    k <<= 1;
+                    if !c.is_null() {
+                        t = *c;
+                    } else {
+                        *c = chunk;
+                        (*chunk).parent = t;
+                        (*chunkc).next = chunkc;
+                        (*chunkc).prev = chunkc;
+                        break;
+                    }
+                } else {
+                    let tc = TreeChunk::chunk(t);
+                    let f = (*tc).prev;
+                    (*f).next = chunkc;
+                    (*tc).prev = chunkc;
+                    (*chunkc).prev = f;
+                    (*chunkc).next = tc;
+                    (*chunk).parent = ptr::null_mut();
+                    break;
+                }
+            }
+        }
+    }
+
+    unsafe fn smallmap_is_marked(&self, idx: u32) -> bool {
+        self.smallmap & (1 << idx) != 0
+    }
+
+    unsafe fn mark_smallmap(&mut self, idx: u32) {
+        self.smallmap |= 1 << idx;
+    }
+
+    unsafe fn clear_smallmap(&mut self, idx: u32) {
+        self.smallmap &= !(1 << idx);
+    }
+
+    unsafe fn treemap_is_marked(&self, idx: u32) -> bool {
+        self.treemap & (1 << idx) != 0
+    }
+
+    unsafe fn mark_treemap(&mut self, idx: u32) {
+        self.treemap |= 1 << idx;
+    }
+
+    unsafe fn clear_treemap(&mut self, idx: u32) {
+        self.treemap &= !(1 << idx);
+    }
+
+    unsafe fn unlink_chunk(&mut self, chunk: *mut Chunk, size: usize) {
+        if self.is_small(size) {
+            self.unlink_small_chunk(chunk, size)
+        } else {
+            self.unlink_large_chunk(chunk as *mut TreeChunk);
+        }
+    }
+
+    unsafe fn unlink_small_chunk(&mut self, chunk: *mut Chunk, size: usize) {
+        let f = (*chunk).prev;
+        let b = (*chunk).next;
+        let idx = self.small_index(size);
+        debug_assert!(chunk != b);
+        debug_assert!(chunk != f);
+        debug_assert_eq!(Chunk::size(chunk), self.small_index2size(idx));
+        if b == f {
+            self.clear_smallmap(idx);
+        } else {
+            (*f).next = b;
+            (*b).prev = f;
+        }
+    }
+
+    unsafe fn unlink_large_chunk(&mut self, chunk: *mut TreeChunk) {
+        let xp = (*chunk).parent;
+        let mut r;
+        if TreeChunk::next(chunk) != chunk {
+            let f = TreeChunk::prev(chunk);
+            r = TreeChunk::next(chunk);
+            (*f).chunk.next = TreeChunk::chunk(r);
+            (*r).chunk.prev = TreeChunk::chunk(f);
+        } else {
+            let mut rp = &mut (*chunk).child[1];
+            if rp.is_null() {
+                rp = &mut (*chunk).child[0];
+            }
+            r = *rp;
+            if !rp.is_null() {
+                loop {
+                    let mut cp = &mut (**rp).child[1];
+                    if cp.is_null() {
+                        cp = &mut (**rp).child[0];
+                    }
+                    if cp.is_null() {
+                        break;
+                    }
+                    rp = cp;
+                }
+                r = *rp;
+                *rp = ptr::null_mut();
+            }
+        }
+
+        if xp.is_null() {
+            return;
+        }
+
+        let h = self.treebin_at((*chunk).index);
+        if chunk == *h {
+            *h = r;
+            if r.is_null() {
+                self.clear_treemap((*chunk).index);
+            }
+        } else {
+            if (*xp).child[0] == chunk {
+                (*xp).child[0] = r;
+            } else {
+                (*xp).child[1] = r;
+            }
+        }
+
+        if !r.is_null() {
+            (*r).parent = xp;
+            let c0 = (*chunk).child[0];
+            if !c0.is_null() {
+                (*r).child[0] = c0;
+                (*c0).parent = r;
+            }
+            let c1 = (*chunk).child[1];
+            if !c1.is_null() {
+                (*r).child[1] = c1;
+                (*c1).parent = r;
+            }
+        }
+    }
+
+    pub unsafe fn free(&mut self, mem: *mut u8) {
+        self.check_malloc_state();
+
+        let mut p = Chunk::from_mem(mem);
+        let mut psize = Chunk::size(p);
+        let next = Chunk::plus_offset(p, psize);
+        if !Chunk::pinuse(p) {
+            let prevsize = (*p).prev_foot;
+
+            if Chunk::mmapped(p) {
+                psize += prevsize + self.mmap_foot_pad();
+                if self
+                    .system_allocator
+                    .free((p as *mut u8).offset(-(prevsize as isize)), psize)
+                {
+                    self.footprint -= psize;
+                }
+                return;
+            }
+
+            let prev = Chunk::minus_offset(p, prevsize);
+            psize += prevsize;
+            p = prev;
+            if p != self.dv {
+                self.unlink_chunk(p, prevsize);
+            } else if (*next).head & INUSE == INUSE {
+                self.dvsize = psize;
+                Chunk::set_free_with_pinuse(p, psize, next);
+                return;
+            }
+        }
+
+        // Consolidate forward if we can
+        if !Chunk::cinuse(next) {
+            if next == self.top {
+                self.topsize += psize;
+                let tsize = self.topsize;
+                self.top = p;
+                (*p).head = tsize | PINUSE;
+                if p == self.dv {
+                    self.dv = ptr::null_mut();
+                    self.dvsize = 0;
+                }
+                if self.should_trim(tsize) {
+                    self.sys_trim(0);
+                }
+                return;
+            } else if next == self.dv {
+                self.dvsize += psize;
+                let dsize = self.dvsize;
+                self.dv = p;
+                Chunk::set_size_and_pinuse_of_free_chunk(p, dsize);
+                return;
+            } else {
+                let nsize = Chunk::size(next);
+                psize += nsize;
+                self.unlink_chunk(next, nsize);
+                Chunk::set_size_and_pinuse_of_free_chunk(p, psize);
+                if p == self.dv {
+                    self.dvsize = psize;
+                    return;
+                }
+            }
+        } else {
+            Chunk::set_free_with_pinuse(p, psize, next);
+        }
+
+        if self.is_small(psize) {
+            self.insert_small_chunk(p, psize);
+            self.check_free_chunk(p);
+        } else {
+            self.insert_large_chunk(p as *mut TreeChunk, psize);
+            self.check_free_chunk(p);
+            self.release_checks -= 1;
+            if self.release_checks == 0 {
+                self.release_unused_segments();
+            }
+        }
+    }
+
+    fn should_trim(&self, size: usize) -> bool {
+        size > self.trim_check
+    }
+
+    unsafe fn sys_trim(&mut self, mut pad: usize) -> bool {
+        let mut released = 0;
+        if pad < self.max_request() && !self.top.is_null() {
+            pad += self.top_foot_size();
+            if self.topsize > pad {
+                let unit = DEFAULT_GRANULARITY;
+                let extra = ((self.topsize - pad + unit - 1) / unit - 1) * unit;
+                let sp = self.segment_holding(self.top as *mut u8);
+                debug_assert!(!sp.is_null());
+
+                if !Segment::is_extern(sp) {
+                    if Segment::can_release_part(&self.system_allocator, sp) {
+                        if (*sp).size >= extra && !self.has_segment_link(sp) {
+                            let newsize = (*sp).size - extra;
+                            if self
+                                .system_allocator
+                                .free_part((*sp).base, (*sp).size, newsize)
+                            {
+                                released = extra;
+                            }
+                        }
+                    }
+                }
+
+                if released != 0 {
+                    (*sp).size -= released;
+                    self.footprint -= released;
+                    let top = self.top;
+                    let topsize = self.topsize - released;
+                    self.init_top(top, topsize);
+                    self.check_top_chunk(self.top);
+                }
+            }
+
+            released += self.release_unused_segments();
+
+            if released == 0 && self.topsize > self.trim_check {
+                self.trim_check = usize::max_value();
+            }
+        }
+
+        released != 0
+    }
+
+    unsafe fn has_segment_link(&self, ptr: *mut Segment) -> bool {
+        let mut sp = &self.seg as *const Segment as *mut Segment;
+        while !sp.is_null() {
+            if Segment::holds(ptr, sp as *mut u8) {
+                return true;
+            }
+            sp = (*sp).next;
+        }
+        false
+    }
+
+    /// Unmap and unlink any mapped segments that don't contain used chunks
+    unsafe fn release_unused_segments(&mut self) -> usize {
+        let mut released = 0;
+        let mut nsegs = 0;
+        let mut pred = &mut self.seg as *mut Segment;
+        let mut sp = (*pred).next;
+        while !sp.is_null() {
+            let base = (*sp).base;
+            let size = (*sp).size;
+            let next = (*sp).next;
+            nsegs += 1;
+
+            if Segment::can_release_part(&self.system_allocator, sp) && !Segment::is_extern(sp) {
+                let p = self.align_as_chunk(base);
+                let psize = Chunk::size(p);
+                // We can unmap if the first chunk holds the entire segment and
+                // isn't pinned.
+                let chunk_top = (p as *mut u8).offset(psize as isize);
+                let top = base.offset((size - self.top_foot_size()) as isize);
+                if !Chunk::inuse(p) && chunk_top >= top {
+                    let tp = p as *mut TreeChunk;
+                    debug_assert!(Segment::holds(sp, sp as *mut u8));
+                    if p == self.dv {
+                        self.dv = ptr::null_mut();
+                        self.dvsize = 0;
+                    } else {
+                        self.unlink_large_chunk(tp);
+                    }
+                    if self.system_allocator.free(base, size) {
+                        released += size;
+                        self.footprint -= size;
+                        // unlink our obsolete record
+                        sp = pred;
+                        (*sp).next = next;
+                    } else {
+                        // back out if we can't unmap
+                        self.insert_large_chunk(tp, psize);
+                    }
+                }
+            }
+            pred = sp;
+            sp = next;
+        }
+        self.release_checks = if nsegs > MAX_RELEASE_CHECK_RATE {
+            nsegs
+        } else {
+            MAX_RELEASE_CHECK_RATE
+        };
+        return released;
+    }
+
+    // Sanity checks
+
+    unsafe fn check_any_chunk(&self, p: *mut Chunk) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        debug_assert!(
+            self.is_aligned(Chunk::to_mem(p) as usize) || (*p).head == Chunk::fencepost_head()
+        );
+        debug_assert!(p as *mut u8 >= self.least_addr);
+    }
+
+    unsafe fn check_top_chunk(&self, p: *mut Chunk) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        let sp = self.segment_holding(p as *mut u8);
+        let sz = (*p).head & !INUSE;
+        debug_assert!(!sp.is_null());
+        debug_assert!(
+            self.is_aligned(Chunk::to_mem(p) as usize) || (*p).head == Chunk::fencepost_head()
+        );
+        debug_assert!(p as *mut u8 >= self.least_addr);
+        debug_assert_eq!(sz, self.topsize);
+        debug_assert!(sz > 0);
+        debug_assert_eq!(
+            sz,
+            (*sp).base as usize + (*sp).size - p as usize - self.top_foot_size()
+        );
+        debug_assert!(Chunk::pinuse(p));
+        debug_assert!(!Chunk::pinuse(Chunk::plus_offset(p, sz)));
+    }
+
+    unsafe fn check_malloced_chunk(&self, mem: *mut u8, s: usize) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        if mem.is_null() {
+            return;
+        }
+        let p = Chunk::from_mem(mem);
+        let sz = (*p).head & !INUSE;
+        self.check_inuse_chunk(p);
+        debug_assert_eq!(align_up(sz, self.malloc_alignment()), sz);
+        debug_assert!(sz >= self.min_chunk_size());
+        debug_assert!(sz >= s);
+        debug_assert!(Chunk::mmapped(p) || sz < (s + self.min_chunk_size()));
+    }
+
+    unsafe fn check_inuse_chunk(&self, p: *mut Chunk) {
+        self.check_any_chunk(p);
+        debug_assert!(Chunk::inuse(p));
+        debug_assert!(Chunk::pinuse(Chunk::next(p)));
+        debug_assert!(Chunk::mmapped(p) || Chunk::pinuse(p) || Chunk::next(Chunk::prev(p)) == p);
+        if Chunk::mmapped(p) {
+            self.check_mmapped_chunk(p);
+        }
+    }
+
+    unsafe fn check_mmapped_chunk(&self, p: *mut Chunk) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        let sz = Chunk::size(p);
+        let len = sz + (*p).prev_foot + self.mmap_foot_pad();
+        debug_assert!(Chunk::mmapped(p));
+        debug_assert!(
+            self.is_aligned(Chunk::to_mem(p) as usize) || (*p).head == Chunk::fencepost_head()
+        );
+        debug_assert!(p as *mut u8 >= self.least_addr);
+        debug_assert!(!self.is_small(sz));
+        debug_assert_eq!(align_up(len, self.system_allocator.page_size()), len);
+        debug_assert_eq!((*Chunk::plus_offset(p, sz)).head, Chunk::fencepost_head());
+        debug_assert_eq!(
+            (*Chunk::plus_offset(p, sz + mem::size_of::<usize>())).head,
+            0
+        );
+    }
+
+    unsafe fn check_free_chunk(&self, p: *mut Chunk) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        let sz = Chunk::size(p);
+        let next = Chunk::plus_offset(p, sz);
+        self.check_any_chunk(p);
+        debug_assert!(!Chunk::inuse(p));
+        debug_assert!(!Chunk::pinuse(Chunk::next(p)));
+        debug_assert!(!Chunk::mmapped(p));
+        if p != self.dv && p != self.top {
+            if sz >= self.min_chunk_size() {
+                debug_assert_eq!(align_up(sz, self.malloc_alignment()), sz);
+                debug_assert!(self.is_aligned(Chunk::to_mem(p) as usize));
+                debug_assert_eq!((*next).prev_foot, sz);
+                debug_assert!(Chunk::pinuse(p));
+                debug_assert!(next == self.top || Chunk::inuse(next));
+                debug_assert_eq!((*(*p).next).prev, p);
+                debug_assert_eq!((*(*p).prev).next, p);
+            } else {
+                debug_assert_eq!(sz, mem::size_of::<usize>());
+            }
+        }
+    }
+
+    unsafe fn check_malloc_state(&mut self) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        for i in 0..NSMALLBINS {
+            self.check_smallbin(i as u32);
+        }
+        for i in 0..NTREEBINS {
+            self.check_treebin(i as u32);
+        }
+        if self.dvsize != 0 {
+            self.check_any_chunk(self.dv);
+            debug_assert_eq!(self.dvsize, Chunk::size(self.dv));
+            debug_assert!(self.dvsize >= self.min_chunk_size());
+            let dv = self.dv;
+            debug_assert!(!self.bin_find(dv));
+        }
+        if !self.top.is_null() {
+            self.check_top_chunk(self.top);
+            debug_assert!(self.topsize > 0);
+            let top = self.top;
+            debug_assert!(!self.bin_find(top));
+        }
+        let total = self.traverse_and_check();
+        debug_assert!(total <= self.footprint);
+        debug_assert!(self.footprint <= self.max_footprint);
+    }
+
+    unsafe fn check_smallbin(&mut self, idx: u32) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        let b = self.smallbin_at(idx);
+        let mut p = (*b).next;
+        let empty = self.smallmap & (1 << idx) == 0;
+        if p == b {
+            debug_assert!(empty)
+        }
+        if !empty {
+            while p != b {
+                let size = Chunk::size(p);
+                self.check_free_chunk(p);
+                debug_assert_eq!(self.small_index(size), idx);
+                debug_assert!((*p).next == b || Chunk::size((*p).next) == Chunk::size(p));
+                let q = Chunk::next(p);
+                if (*q).head != Chunk::fencepost_head() {
+                    self.check_inuse_chunk(q);
+                }
+                p = (*p).next;
+            }
+        }
+    }
+
+    unsafe fn check_treebin(&mut self, idx: u32) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        let tb = self.treebin_at(idx);
+        let t = *tb;
+        let empty = self.treemap & (1 << idx) == 0;
+        if t.is_null() {
+            debug_assert!(empty);
+        }
+        if !empty {
+            self.check_tree(t);
+        }
+    }
+
+    unsafe fn check_tree(&mut self, t: *mut TreeChunk) {
+        if !cfg!(debug_assertions) {
+            return;
+        }
+        let tc = TreeChunk::chunk(t);
+        let tindex = (*t).index;
+        let tsize = Chunk::size(tc);
+        let idx = self.compute_tree_index(tsize);
+        debug_assert_eq!(tindex, idx);
+        debug_assert!(tsize >= self.min_large_size());
+        debug_assert!(tsize >= self.min_size_for_tree_index(idx));
+        debug_assert!(idx == NTREEBINS as u32 - 1 || tsize < self.min_size_for_tree_index(idx + 1));
+
+        let mut u = t;
+        let mut head = ptr::null_mut::<TreeChunk>();
+        loop {
+            let uc = TreeChunk::chunk(u);
+            self.check_any_chunk(uc);
+            debug_assert_eq!((*u).index, tindex);
+            debug_assert_eq!(Chunk::size(uc), tsize);
+            debug_assert!(!Chunk::inuse(uc));
+            debug_assert!(!Chunk::pinuse(Chunk::next(uc)));
+            debug_assert_eq!((*(*uc).next).prev, uc);
+            debug_assert_eq!((*(*uc).prev).next, uc);
+            let left = (*u).child[0];
+            let right = (*u).child[1];
+            if (*u).parent.is_null() {
+                debug_assert!(left.is_null());
+                debug_assert!(right.is_null());
+            } else {
+                debug_assert!(head.is_null());
+                head = u;
+                debug_assert!((*u).parent != u);
+                debug_assert!(
+                    (*(*u).parent).child[0] == u
+                        || (*(*u).parent).child[1] == u
+                        || *((*u).parent as *mut *mut TreeChunk) == u
+                );
+                if !left.is_null() {
+                    debug_assert_eq!((*left).parent, u);
+                    debug_assert!(left != u);
+                    self.check_tree(left);
+                }
+                if !right.is_null() {
+                    debug_assert_eq!((*right).parent, u);
+                    debug_assert!(right != u);
+                    self.check_tree(right);
+                }
+                if !left.is_null() && !right.is_null() {
+                    debug_assert!(
+                        Chunk::size(TreeChunk::chunk(left)) < Chunk::size(TreeChunk::chunk(right))
+                    );
+                }
+            }
+
+            u = TreeChunk::prev(u);
+            if u == t {
+                break;
+            }
+        }
+        debug_assert!(!head.is_null());
+    }
+
+    fn min_size_for_tree_index(&self, idx: u32) -> usize {
+        let idx = idx as usize;
+        (1 << ((idx >> 1) + TREEBIN_SHIFT)) | ((idx & 1) << ((idx >> 1) + TREEBIN_SHIFT - 1))
+    }
+
+    unsafe fn bin_find(&mut self, chunk: *mut Chunk) -> bool {
+        let size = Chunk::size(chunk);
+        if self.is_small(size) {
+            let sidx = self.small_index(size);
+            let b = self.smallbin_at(sidx);
+            if !self.smallmap_is_marked(sidx) {
+                return false;
+            }
+            let mut p = b;
+            loop {
+                if p == chunk {
+                    return true;
+                }
+                p = (*p).prev;
+                if p == b {
+                    return false;
+                }
+            }
+        } else {
+            let tidx = self.compute_tree_index(size);
+            if !self.treemap_is_marked(tidx) {
+                return false;
+            }
+            let mut t = *self.treebin_at(tidx);
+            let mut sizebits = size << leftshift_for_tree_index(tidx);
+            while !t.is_null() && Chunk::size(TreeChunk::chunk(t)) != size {
+                t = (*t).child[(sizebits >> (mem::size_of::<usize>() * 8 - 1)) & 1];
+                sizebits <<= 1;
+            }
+            if t.is_null() {
+                return false;
+            }
+            let mut u = t;
+            let chunk = chunk as *mut TreeChunk;
+            loop {
+                if u == chunk {
+                    return true;
+                }
+                u = TreeChunk::prev(u);
+                if u == t {
+                    return false;
+                }
+            }
+        }
+    }
+
+    unsafe fn traverse_and_check(&self) -> usize {
+        0
+    }
+}
+
+const PINUSE: usize = 1 << 0;
+const CINUSE: usize = 1 << 1;
+const FLAG4: usize = 1 << 2;
+const INUSE: usize = PINUSE | CINUSE;
+const FLAG_BITS: usize = PINUSE | CINUSE | FLAG4;
+
+impl Chunk {
+    unsafe fn fencepost_head() -> usize {
+        INUSE | mem::size_of::<usize>()
+    }
+
+    unsafe fn size(me: *mut Chunk) -> usize {
+        (*me).head & !FLAG_BITS
+    }
+
+    unsafe fn next(me: *mut Chunk) -> *mut Chunk {
+        (me as *mut u8).offset(((*me).head & !FLAG_BITS) as isize) as *mut Chunk
+    }
+
+    unsafe fn prev(me: *mut Chunk) -> *mut Chunk {
+        (me as *mut u8).offset(-((*me).prev_foot as isize)) as *mut Chunk
+    }
+
+    unsafe fn cinuse(me: *mut Chunk) -> bool {
+        (*me).head & CINUSE != 0
+    }
+
+    unsafe fn pinuse(me: *mut Chunk) -> bool {
+        (*me).head & PINUSE != 0
+    }
+
+    unsafe fn clear_pinuse(me: *mut Chunk) {
+        (*me).head &= !PINUSE;
+    }
+
+    unsafe fn inuse(me: *mut Chunk) -> bool {
+        (*me).head & INUSE != PINUSE
+    }
+
+    unsafe fn mmapped(me: *mut Chunk) -> bool {
+        (*me).head & INUSE == 0
+    }
+
+    unsafe fn set_inuse(me: *mut Chunk, size: usize) {
+        (*me).head = ((*me).head & PINUSE) | size | CINUSE;
+        let next = Chunk::plus_offset(me, size);
+        (*next).head |= PINUSE;
+    }
+
+    unsafe fn set_inuse_and_pinuse(me: *mut Chunk, size: usize) {
+        (*me).head = PINUSE | size | CINUSE;
+        let next = Chunk::plus_offset(me, size);
+        (*next).head |= PINUSE;
+    }
+
+    unsafe fn set_size_and_pinuse_of_inuse_chunk(me: *mut Chunk, size: usize) {
+        (*me).head = size | PINUSE | CINUSE;
+    }
+
+    unsafe fn set_size_and_pinuse_of_free_chunk(me: *mut Chunk, size: usize) {
+        (*me).head = size | PINUSE;
+        Chunk::set_foot(me, size);
+    }
+
+    unsafe fn set_free_with_pinuse(p: *mut Chunk, size: usize, n: *mut Chunk) {
+        Chunk::clear_pinuse(n);
+        Chunk::set_size_and_pinuse_of_free_chunk(p, size);
+    }
+
+    unsafe fn set_foot(me: *mut Chunk, size: usize) {
+        let next = Chunk::plus_offset(me, size);
+        (*next).prev_foot = size;
+    }
+
+    unsafe fn plus_offset(me: *mut Chunk, offset: usize) -> *mut Chunk {
+        (me as *mut u8).offset(offset as isize) as *mut Chunk
+    }
+
+    unsafe fn minus_offset(me: *mut Chunk, offset: usize) -> *mut Chunk {
+        (me as *mut u8).offset(-(offset as isize)) as *mut Chunk
+    }
+
+    unsafe fn to_mem(me: *mut Chunk) -> *mut u8 {
+        (me as *mut u8).offset(Chunk::mem_offset())
+    }
+
+    fn mem_offset() -> isize {
+        2 * (mem::size_of::<usize>() as isize)
+    }
+
+    unsafe fn from_mem(mem: *mut u8) -> *mut Chunk {
+        mem.offset(-2 * (mem::size_of::<usize>() as isize)) as *mut Chunk
+    }
+}
+
+impl TreeChunk {
+    unsafe fn leftmost_child(me: *mut TreeChunk) -> *mut TreeChunk {
+        let left = (*me).child[0];
+        if left.is_null() {
+            (*me).child[1]
+        } else {
+            left
+        }
+    }
+
+    unsafe fn chunk(me: *mut TreeChunk) -> *mut Chunk {
+        &mut (*me).chunk
+    }
+
+    unsafe fn next(me: *mut TreeChunk) -> *mut TreeChunk {
+        (*TreeChunk::chunk(me)).next as *mut TreeChunk
+    }
+
+    unsafe fn prev(me: *mut TreeChunk) -> *mut TreeChunk {
+        (*TreeChunk::chunk(me)).prev as *mut TreeChunk
+    }
+}
+
+const EXTERN: u32 = 1 << 0;
+
+impl Segment {
+    unsafe fn is_extern(seg: *mut Segment) -> bool {
+        (*seg).flags & EXTERN != 0
+    }
+
+    unsafe fn can_release_part<A: Allocator>(system_allocator: &A, seg: *mut Segment) -> bool {
+        system_allocator.can_release_part((*seg).flags >> 1)
+    }
+
+    unsafe fn sys_flags(seg: *mut Segment) -> u32 {
+        (*seg).flags >> 1
+    }
+
+    unsafe fn holds(seg: *mut Segment, addr: *mut u8) -> bool {
+        (*seg).base <= addr && addr < Segment::top(seg)
+    }
+
+    unsafe fn top(seg: *mut Segment) -> *mut u8 {
+        (*seg).base.offset((*seg).size as isize)
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use System;
+
+    // Prime the allocator with some allocations such that there will be free
+    // chunks in the treemap
+    unsafe fn setup_treemap<A: Allocator>(a: &mut Dlmalloc<A>) {
+        let large_request_size = NSMALLBINS * (1 << SMALLBIN_SHIFT);
+        assert!(!a.is_small(large_request_size));
+        let large_request1 = a.malloc(large_request_size);
+        assert_ne!(large_request1, ptr::null_mut());
+        let large_request2 = a.malloc(large_request_size);
+        assert_ne!(large_request2, ptr::null_mut());
+        a.free(large_request1);
+        assert_ne!(a.treemap, 0);
+    }
+
+    #[test]
+    // Test allocating, with a non-empty treemap, a specific size that used to
+    // trigger an integer overflow bug
+    fn treemap_alloc_overflow_minimal() {
+        let mut a = Dlmalloc::new(System::new());
+        unsafe {
+            setup_treemap(&mut a);
+            let min_idx31_size = (0xc000 << TREEBIN_SHIFT) - a.chunk_overhead() + 1;
+            assert_ne!(a.malloc(min_idx31_size), ptr::null_mut());
+        }
+    }
+
+    #[test]
+    // Test allocating the maximum request size with a non-empty treemap
+    fn treemap_alloc_max() {
+        let mut a = Dlmalloc::new(System::new());
+        unsafe {
+            setup_treemap(&mut a);
+            let max_request_size = a.max_request() - 1;
+            assert_eq!(a.malloc(max_request_size), ptr::null_mut());
+        }
+    }
+}
diff --git a/vendor/dlmalloc/src/dummy.rs b/vendor/dlmalloc/src/dummy.rs
new file mode 100644
index 000000000..bd8d5b6e2
--- /dev/null
+++ b/vendor/dlmalloc/src/dummy.rs
@@ -0,0 +1,42 @@
+use core::ptr;
+use Allocator;
+
+pub struct System {
+    _priv: (),
+}
+
+impl System {
+    pub const fn new() -> System {
+        System { _priv: () }
+    }
+}
+
+unsafe impl Allocator for System {
+    fn alloc(&self, _size: usize) -> (*mut u8, usize, u32) {
+        (ptr::null_mut(), 0, 0)
+    }
+
+    fn remap(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize, _can_move: bool) -> *mut u8 {
+        ptr::null_mut()
+    }
+
+    fn free_part(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize) -> bool {
+        false
+    }
+
+    fn free(&self, _ptr: *mut u8, _size: usize) -> bool {
+        false
+    }
+
+    fn can_release_part(&self, _flags: u32) -> bool {
+        false
+    }
+
+    fn allocates_zeros(&self) -> bool {
+        false
+    }
+
+    fn page_size(&self) -> usize {
+        1
+    }
+}
diff --git a/vendor/dlmalloc/src/global.rs b/vendor/dlmalloc/src/global.rs
new file mode 100644
index 000000000..c761fdeaf
--- /dev/null
+++ b/vendor/dlmalloc/src/global.rs
@@ -0,0 +1,62 @@
+use core::alloc::{GlobalAlloc, Layout};
+use core::ops::{Deref, DerefMut};
+
+use Dlmalloc;
+
+pub use sys::enable_alloc_after_fork;
+
+/// An instance of a "global allocator" backed by `Dlmalloc`
+///
+/// This API requires the `global` feature is activated, and this type
+/// implements the `GlobalAlloc` trait in the standard library.
+pub struct GlobalDlmalloc;
+
+unsafe impl GlobalAlloc for GlobalDlmalloc {
+    #[inline]
+    unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+        <Dlmalloc>::malloc(&mut get(), layout.size(), layout.align())
+    }
+
+    #[inline]
+    unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+        <Dlmalloc>::free(&mut get(), ptr, layout.size(), layout.align())
+    }
+
+    #[inline]
+    unsafe fn alloc_zeroed(&self, layout: Layout) -> *mut u8 {
+        <Dlmalloc>::calloc(&mut get(), layout.size(), layout.align())
+    }
+
+    #[inline]
+    unsafe fn realloc(&self, ptr: *mut u8, layout: Layout, new_size: usize) -> *mut u8 {
+        <Dlmalloc>::realloc(&mut get(), ptr, layout.size(), layout.align(), new_size)
+    }
+}
+
+static mut DLMALLOC: Dlmalloc = Dlmalloc::new();
+
+struct Instance;
+
+unsafe fn get() -> Instance {
+    ::sys::acquire_global_lock();
+    Instance
+}
+
+impl Deref for Instance {
+    type Target = Dlmalloc;
+    fn deref(&self) -> &Dlmalloc {
+        unsafe { &DLMALLOC }
+    }
+}
+
+impl DerefMut for Instance {
+    fn deref_mut(&mut self) -> &mut Dlmalloc {
+        unsafe { &mut DLMALLOC }
+    }
+}
+
+impl Drop for Instance {
+    fn drop(&mut self) {
+        ::sys::release_global_lock()
+    }
+}
diff --git a/vendor/dlmalloc/src/lib.rs b/vendor/dlmalloc/src/lib.rs
new file mode 100644
index 000000000..238386fbc
--- /dev/null
+++ b/vendor/dlmalloc/src/lib.rs
@@ -0,0 +1,170 @@
+//! A Rust port of the `dlmalloc` allocator.
+//!
+//! The `dlmalloc` allocator is described at
+//! http://g.oswego.edu/dl/html/malloc.html and this Rust crate is a straight
+//! port of the C code for the allocator into Rust. The implementation is
+//! wrapped up in a `Dlmalloc` type and has support for Linux, OSX, and Wasm
+//! currently.
+//!
+//! The primary purpose of this crate is that it serves as the default memory
+//! allocator for the `wasm32-unknown-unknown` target in the standard library.
+//! Support for other platforms is largely untested and unused, but is used when
+//! testing this crate.
+
+#![allow(dead_code)]
+#![no_std]
+#![deny(missing_docs)]
+#![cfg_attr(target_arch = "wasm64", feature(simd_wasm64))]
+
+use core::cmp;
+use core::ptr;
+use sys::System;
+
+#[cfg(feature = "global")]
+pub use self::global::{enable_alloc_after_fork, GlobalDlmalloc};
+
+mod dlmalloc;
+#[cfg(feature = "global")]
+mod global;
+
+/// In order for this crate to efficiently manage memory, it needs a way to communicate with the
+/// underlying platform. This `Allocator` trait provides an interface for this communication.
+pub unsafe trait Allocator: Send {
+    /// Allocates system memory region of at least `size` bytes
+    /// Returns a triple of `(base, size, flags)` where `base` is a pointer to the beginning of the
+    /// allocated memory region. `size` is the actual size of the region while `flags` specifies
+    /// properties of the allocated region. If `EXTERN_BIT` (bit 0) set in flags, then we did not
+    /// allocate this segment and so should not try to deallocate or merge with others.
+    /// This function can return a `std::ptr::null_mut()` when allocation fails (other values of
+    /// the triple will be ignored).
+    fn alloc(&self, size: usize) -> (*mut u8, usize, u32);
+
+    /// Remaps system memory region at `ptr` with size `oldsize` to a potential new location with
+    /// size `newsize`. `can_move` indicates if the location is allowed to move to a completely new
+    /// location, or that it is only allowed to change in size. Returns a pointer to the new
+    /// location in memory.
+    /// This function can return a `std::ptr::null_mut()` to signal an error.
+    fn remap(&self, ptr: *mut u8, oldsize: usize, newsize: usize, can_move: bool) -> *mut u8;
+
+    /// Frees a part of a memory chunk. The original memory chunk starts at `ptr` with size `oldsize`
+    /// and is turned into a memory region starting at the same address but with `newsize` bytes.
+    /// Returns `true` iff the access memory region could be freed.
+    fn free_part(&self, ptr: *mut u8, oldsize: usize, newsize: usize) -> bool;
+
+    /// Frees an entire memory region. Returns `true` iff the operation succeeded. When `false` is
+    /// returned, the `dlmalloc` may re-use the location on future allocation requests
+    fn free(&self, ptr: *mut u8, size: usize) -> bool;
+
+    /// Indicates if the system can release a part of memory. For the `flags` argument, see
+    /// `Allocator::alloc`
+    fn can_release_part(&self, flags: u32) -> bool;
+
+    /// Indicates whether newly allocated regions contain zeros.
+    fn allocates_zeros(&self) -> bool;
+
+    /// Returns the page size. Must be a power of two
+    fn page_size(&self) -> usize;
+}
+
+/// An allocator instance
+///
+/// Instances of this type are used to allocate blocks of memory. For best
+/// results only use one of these. Currently doesn't implement `Drop` to release
+/// lingering memory back to the OS. That may happen eventually though!
+pub struct Dlmalloc<A = System>(dlmalloc::Dlmalloc<A>);
+
+#[cfg(target_family = "wasm")]
+#[path = "wasm.rs"]
+mod sys;
+
+#[cfg(any(target_os = "linux", target_os = "macos"))]
+#[path = "unix.rs"]
+mod sys;
+
+#[cfg(not(any(target_os = "linux", target_os = "macos", target_family = "wasm")))]
+#[path = "dummy.rs"]
+mod sys;
+
+impl Dlmalloc<System> {
+    /// Creates a new instance of an allocator
+    pub const fn new() -> Dlmalloc<System> {
+        Dlmalloc(dlmalloc::Dlmalloc::new(System::new()))
+    }
+}
+
+impl<A> Dlmalloc<A> {
+    /// Creates a new instance of an allocator
+    pub const fn new_with_allocator(sys_allocator: A) -> Dlmalloc<A> {
+        Dlmalloc(dlmalloc::Dlmalloc::new(sys_allocator))
+    }
+}
+
+impl<A: Allocator> Dlmalloc<A> {
+    /// Allocates `size` bytes with `align` align.
+    ///
+    /// Returns a null pointer if allocation fails. Returns a valid pointer
+    /// otherwise.
+    ///
+    /// Safety and contracts are largely governed by the `GlobalAlloc::alloc`
+    /// method contracts.
+    #[inline]
+    pub unsafe fn malloc(&mut self, size: usize, align: usize) -> *mut u8 {
+        if align <= self.0.malloc_alignment() {
+            self.0.malloc(size)
+        } else {
+            self.0.memalign(align, size)
+        }
+    }
+
+    /// Same as `malloc`, except if the allocation succeeds it's guaranteed to
+    /// point to `size` bytes of zeros.
+    #[inline]
+    pub unsafe fn calloc(&mut self, size: usize, align: usize) -> *mut u8 {
+        let ptr = self.malloc(size, align);
+        if !ptr.is_null() && self.0.calloc_must_clear(ptr) {
+            ptr::write_bytes(ptr, 0, size);
+        }
+        ptr
+    }
+
+    /// Deallocates a `ptr` with `size` and `align` as the previous request used
+    /// to allocate it.
+    ///
+    /// Safety and contracts are largely governed by the `GlobalAlloc::dealloc`
+    /// method contracts.
+    #[inline]
+    pub unsafe fn free(&mut self, ptr: *mut u8, size: usize, align: usize) {
+        drop((size, align));
+        self.0.free(ptr)
+    }
+
+    /// Reallocates `ptr`, a previous allocation with `old_size` and
+    /// `old_align`, to have `new_size` and the same alignment as before.
+    ///
+    /// Returns a null pointer if the memory couldn't be reallocated, but `ptr`
+    /// is still valid. Returns a valid pointer and frees `ptr` if the request
+    /// is satisfied.
+    ///
+    /// Safety and contracts are largely governed by the `GlobalAlloc::realloc`
+    /// method contracts.
+    #[inline]
+    pub unsafe fn realloc(
+        &mut self,
+        ptr: *mut u8,
+        old_size: usize,
+        old_align: usize,
+        new_size: usize,
+    ) -> *mut u8 {
+        if old_align <= self.0.malloc_alignment() {
+            self.0.realloc(ptr, new_size)
+        } else {
+            let res = self.malloc(new_size, old_align);
+            if !res.is_null() {
+                let size = cmp::min(old_size, new_size);
+                ptr::copy_nonoverlapping(ptr, res, size);
+                self.free(ptr, old_size, old_align);
+            }
+            res
+        }
+    }
+}
diff --git a/vendor/dlmalloc/src/unix.rs b/vendor/dlmalloc/src/unix.rs
new file mode 100644
index 000000000..a4f9914ec
--- /dev/null
+++ b/vendor/dlmalloc/src/unix.rs
@@ -0,0 +1,133 @@
+extern crate libc;
+
+use core::ptr;
+use Allocator;
+
+/// System setting for Linux
+pub struct System {
+    _priv: (),
+}
+
+impl System {
+    pub const fn new() -> System {
+        System { _priv: () }
+    }
+}
+
+#[cfg(feature = "global")]
+static mut LOCK: libc::pthread_mutex_t = libc::PTHREAD_MUTEX_INITIALIZER;
+
+unsafe impl Allocator for System {
+    fn alloc(&self, size: usize) -> (*mut u8, usize, u32) {
+        let addr = unsafe {
+            libc::mmap(
+                0 as *mut _,
+                size,
+                libc::PROT_WRITE | libc::PROT_READ,
+                libc::MAP_ANON | libc::MAP_PRIVATE,
+                -1,
+                0,
+            )
+        };
+        if addr == libc::MAP_FAILED {
+            (ptr::null_mut(), 0, 0)
+        } else {
+            (addr as *mut u8, size, 0)
+        }
+    }
+
+    #[cfg(target_os = "linux")]
+    fn remap(&self, ptr: *mut u8, oldsize: usize, newsize: usize, can_move: bool) -> *mut u8 {
+        let flags = if can_move { libc::MREMAP_MAYMOVE } else { 0 };
+        let ptr = unsafe { libc::mremap(ptr as *mut _, oldsize, newsize, flags) };
+        if ptr == libc::MAP_FAILED {
+            ptr::null_mut()
+        } else {
+            ptr as *mut u8
+        }
+    }
+
+    #[cfg(target_os = "macos")]
+    fn remap(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize, _can_move: bool) -> *mut u8 {
+        ptr::null_mut()
+    }
+
+    #[cfg(target_os = "linux")]
+    fn free_part(&self, ptr: *mut u8, oldsize: usize, newsize: usize) -> bool {
+        unsafe {
+            let rc = libc::mremap(ptr as *mut _, oldsize, newsize, 0);
+            if rc != libc::MAP_FAILED {
+                return true;
+            }
+            libc::munmap(ptr.offset(newsize as isize) as *mut _, oldsize - newsize) == 0
+        }
+    }
+
+    #[cfg(target_os = "macos")]
+    fn free_part(&self, ptr: *mut u8, oldsize: usize, newsize: usize) -> bool {
+        unsafe { libc::munmap(ptr.offset(newsize as isize) as *mut _, oldsize - newsize) == 0 }
+    }
+
+    fn free(&self, ptr: *mut u8, size: usize) -> bool {
+        unsafe { libc::munmap(ptr as *mut _, size) == 0 }
+    }
+
+    fn can_release_part(&self, _flags: u32) -> bool {
+        true
+    }
+
+    fn allocates_zeros(&self) -> bool {
+        true
+    }
+
+    fn page_size(&self) -> usize {
+        4096
+    }
+}
+
+#[cfg(feature = "global")]
+pub fn acquire_global_lock() {
+    unsafe { assert_eq!(libc::pthread_mutex_lock(&mut LOCK), 0) }
+}
+
+#[cfg(feature = "global")]
+pub fn release_global_lock() {
+    unsafe { assert_eq!(libc::pthread_mutex_unlock(&mut LOCK), 0) }
+}
+
+#[cfg(feature = "global")]
+/// allows the allocator to remain unsable in the child process,
+/// after a call to `fork(2)`
+///
+/// #Safety
+///
+/// if used, this function must be called,
+/// before any allocations are made with the global allocator.
+pub unsafe fn enable_alloc_after_fork() {
+    // atfork must only be called once, to avoid a deadlock,
+    // where the handler attempts to acquire the global lock twice
+    static mut FORK_PROTECTED: bool = false;
+
+    unsafe extern "C" fn _acquire_global_lock() {
+        acquire_global_lock()
+    }
+
+    unsafe extern "C" fn _release_global_lock() {
+        release_global_lock()
+    }
+
+    acquire_global_lock();
+    // if a process forks,
+    // it will acquire the lock before any other thread,
+    // protecting it from deadlock,
+    // due to the child being created with only the calling thread.
+    if !FORK_PROTECTED {
+        libc::pthread_atfork(
+            Some(_acquire_global_lock),
+            Some(_release_global_lock),
+            Some(_release_global_lock),
+        );
+        FORK_PROTECTED = true;
+    }
+    release_global_lock();
+}
diff --git a/vendor/dlmalloc/src/wasm.rs b/vendor/dlmalloc/src/wasm.rs
new file mode 100644
index 000000000..216fe43af
--- /dev/null
+++ b/vendor/dlmalloc/src/wasm.rs
@@ -0,0 +1,72 @@
+#[cfg(target_arch = "wasm32")]
+use core::arch::wasm32 as wasm;
+#[cfg(target_arch = "wasm64")]
+use core::arch::wasm64 as wasm;
+use core::ptr;
+use Allocator;
+
+/// System setting for Wasm
+pub struct System {
+    _priv: (),
+}
+
+impl System {
+    pub const fn new() -> System {
+        System { _priv: () }
+    }
+}
+
+unsafe impl Allocator for System {
+    fn alloc(&self, size: usize) -> (*mut u8, usize, u32) {
+        let pages = size / self.page_size();
+        let prev = wasm::memory_grow(0, pages);
+        if prev == usize::max_value() {
+            return (ptr::null_mut(), 0, 0);
+        }
+        (
+            (prev * self.page_size()) as *mut u8,
+            pages * self.page_size(),
+            0,
+        )
+    }
+
+    fn remap(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize, _can_move: bool) -> *mut u8 {
+        // TODO: I think this can be implemented near the end?
+        ptr::null_mut()
+    }
+
+    fn free_part(&self, _ptr: *mut u8, _oldsize: usize, _newsize: usize) -> bool {
+        false
+    }
+
+    fn free(&self, _ptr: *mut u8, _size: usize) -> bool {
+        false
+    }
+
+    fn can_release_part(&self, _flags: u32) -> bool {
+        false
+    }
+
+    fn allocates_zeros(&self) -> bool {
+        true
+    }
+
+    fn page_size(&self) -> usize {
+        64 * 1024
+    }
+}
+
+#[cfg(feature = "global")]
+pub fn acquire_global_lock() {
+    // single threaded, no need!
+}
+
+#[cfg(feature = "global")]
+pub fn release_global_lock() {
+    // single threaded, no need!
+}
+
+#[cfg(feature = "global")]
+pub unsafe fn enable_alloc_after_fork() {
+    // single threaded, no need!
+}
diff --git a/vendor/dlmalloc/tests/global.rs b/vendor/dlmalloc/tests/global.rs
new file mode 100644
index 000000000..1e9bc66ec
--- /dev/null
+++ b/vendor/dlmalloc/tests/global.rs
@@ -0,0 +1,31 @@
+extern crate dlmalloc;
+
+use std::collections::HashMap;
+use std::thread;
+
+#[global_allocator]
+#[cfg(feature = "global")]
+static A: dlmalloc::GlobalDlmalloc = dlmalloc::GlobalDlmalloc;
+
+#[test]
+fn foo() {
+    println!("hello");
+}
+
+#[test]
+fn map() {
+    let mut m = HashMap::new();
+    m.insert(1, 2);
+    m.insert(5, 3);
+    drop(m);
+}
+
+#[test]
+fn strings() {
+    format!("foo, bar, {}", "baz");
+}
+
+#[test]
+fn threads() {
+    assert!(thread::spawn(|| panic!()).join().is_err());
+}
diff --git a/vendor/dlmalloc/tests/smoke.rs b/vendor/dlmalloc/tests/smoke.rs
new file mode 100644
index 000000000..cd69f9402
--- /dev/null
+++ b/vendor/dlmalloc/tests/smoke.rs
@@ -0,0 +1,91 @@
+extern crate dlmalloc;
+extern crate rand;
+
+use dlmalloc::Dlmalloc;
+use rand::Rng;
+use std::cmp;
+
+#[test]
+fn smoke() {
+    let mut a = Dlmalloc::new();
+    unsafe {
+        let ptr = a.malloc(1, 1);
+        assert!(!ptr.is_null());
+        *ptr = 9;
+        assert_eq!(*ptr, 9);
+        a.free(ptr, 1, 1);
+
+        let ptr = a.malloc(1, 1);
+        assert!(!ptr.is_null());
+        *ptr = 10;
+        assert_eq!(*ptr, 10);
+        a.free(ptr, 1, 1);
+    }
+}
+
+#[test]
+fn stress() {
+    let mut a = Dlmalloc::new();
+    let mut rng = rand::thread_rng();
+    let mut ptrs = Vec::new();
+    let max = if cfg!(test_lots) { 1_000_000 } else { 1_000 };
+    unsafe {
+        for _ in 0..max {
+            let free =
+                ptrs.len() > 0 && ((ptrs.len() < 10_000 && rng.gen_weighted_bool(3)) || rng.gen());
+            if free {
+                let idx = rng.gen_range(0, ptrs.len());
+                let (ptr, size, align) = ptrs.swap_remove(idx);
+                a.free(ptr, size, align);
+                continue;
+            }
+
+            if ptrs.len() > 0 && rng.gen_weighted_bool(100) {
+                let idx = rng.gen_range(0, ptrs.len());
+                let (ptr, size, align) = ptrs.swap_remove(idx);
+                let new_size = if rng.gen() {
+                    rng.gen_range(size, size * 2)
+                } else if size > 10 {
+                    rng.gen_range(size / 2, size)
+                } else {
+                    continue;
+                };
+                let mut tmp = Vec::new();
+                for i in 0..cmp::min(size, new_size) {
+                    tmp.push(*ptr.offset(i as isize));
+                }
+                let ptr = a.realloc(ptr, size, align, new_size);
+                assert!(!ptr.is_null());
+                for (i, byte) in tmp.iter().enumerate() {
+                    assert_eq!(*byte, *ptr.offset(i as isize));
+                }
+                ptrs.push((ptr, new_size, align));
+            }
+
+            let size = if rng.gen() {
+                rng.gen_range(1, 128)
+            } else {
+                rng.gen_range(1, 128 * 1024)
+            };
+            let align = if rng.gen_weighted_bool(10) {
+                1 << rng.gen_range(3, 8)
+            } else {
+                8
+            };
+
+            let zero = rng.gen_weighted_bool(50);
+            let ptr = if zero {
+                a.calloc(size, align)
+            } else {
+                a.malloc(size, align)
+            };
+            for i in 0..size {
+                if zero {
+                    assert_eq!(*ptr.offset(i as isize), 0);
+                }
+                *ptr.offset(i as isize) = 0xce;
+            }
+            ptrs.push((ptr, size, align));
+        }
+    }
+}