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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-19 00:47:55 +0000
commit26a029d407be480d791972afb5975cf62c9360a6 (patch)
treef435a8308119effd964b339f76abb83a57c29483 /other-licenses/snappy
parentInitial commit. (diff)
downloadfirefox-26a029d407be480d791972afb5975cf62c9360a6.tar.xz
firefox-26a029d407be480d791972afb5975cf62c9360a6.zip
Adding upstream version 124.0.1.upstream/124.0.1
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'other-licenses/snappy')
-rw-r--r--other-licenses/snappy/README26
-rw-r--r--other-licenses/snappy/moz.build33
-rw-r--r--other-licenses/snappy/snappy-stubs-public.h56
-rw-r--r--other-licenses/snappy/src/AUTHORS1
-rw-r--r--other-licenses/snappy/src/CONTRIBUTING.md46
-rw-r--r--other-licenses/snappy/src/COPYING54
-rw-r--r--other-licenses/snappy/src/NEWS194
-rw-r--r--other-licenses/snappy/src/README.md140
-rw-r--r--other-licenses/snappy/src/format_description.txt110
-rw-r--r--other-licenses/snappy/src/framing_format.txt135
-rw-r--r--other-licenses/snappy/src/snappy-c.cc90
-rw-r--r--other-licenses/snappy/src/snappy-c.h138
-rw-r--r--other-licenses/snappy/src/snappy-internal.h317
-rw-r--r--other-licenses/snappy/src/snappy-sinksource.cc121
-rw-r--r--other-licenses/snappy/src/snappy-sinksource.h182
-rw-r--r--other-licenses/snappy/src/snappy-stubs-internal.cc42
-rw-r--r--other-licenses/snappy/src/snappy-stubs-internal.h492
-rw-r--r--other-licenses/snappy/src/snappy-stubs-public.h.in63
-rw-r--r--other-licenses/snappy/src/snappy-test.cc503
-rw-r--r--other-licenses/snappy/src/snappy-test.h342
-rw-r--r--other-licenses/snappy/src/snappy.cc2193
-rw-r--r--other-licenses/snappy/src/snappy.h209
-rw-r--r--other-licenses/snappy/src/snappy_compress_fuzzer.cc60
-rw-r--r--other-licenses/snappy/src/snappy_uncompress_fuzzer.cc58
-rw-r--r--other-licenses/snappy/src/snappy_unittest.cc966
25 files changed, 6571 insertions, 0 deletions
diff --git a/other-licenses/snappy/README b/other-licenses/snappy/README
new file mode 100644
index 0000000000..2538acab69
--- /dev/null
+++ b/other-licenses/snappy/README
@@ -0,0 +1,26 @@
+See src/README for the README that ships with snappy.
+
+Mozilla does not modify the actual snappy source with the exception of the
+'snappy-stubs-public.h' header. We have replaced its build system with our own.
+
+Snappy comes from:
+ https://github.com/google/snappy
+
+We are currently using revision: 1.1.9
+
+To upgrade to a newer version:
+ 1. Check out the new code using subversion.
+ 2. Update 'snappy-stubs-public.h' in this directory with any changes that were
+ made to 'snappy-stubs-public.h.in' in the new source.
+ 3. Copy the major/minor/patch versions from 'CMakeLists.txt' into
+ 'snappy-stubs-public.h'.
+ 4. Copy all source files from the new version into the src subdirectory. The
+ following are not needed:
+ - 'CMakeLists.txt', 'snappy_benchmark.cc', 'snappy_test_data.cc',
+ 'snappy_test_data.h', and 'snappy_test_tool.cc' files
+ - 'cmake' subdirectory
+ - 'docs' subdirectory
+ - 'testdata' subdirectory
+ - 'third_party' subdirectory
+ 5. Update the revision stamp in this file.
+
diff --git a/other-licenses/snappy/moz.build b/other-licenses/snappy/moz.build
new file mode 100644
index 0000000000..56fc2ce4c3
--- /dev/null
+++ b/other-licenses/snappy/moz.build
@@ -0,0 +1,33 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXPORTS.snappy += [
+ 'snappy-stubs-public.h',
+ 'src/snappy-c.h',
+ 'src/snappy.h',
+]
+
+UNIFIED_SOURCES += [
+ 'src/snappy-c.cc',
+ 'src/snappy-sinksource.cc',
+ 'src/snappy-stubs-internal.cc',
+ 'src/snappy.cc',
+]
+
+# We allow warnings for third-party code that can be updated from upstream.
+AllowCompilerWarnings()
+
+FINAL_LIBRARY = 'xul'
+
+# Suppress warnings in third-party code.
+if CONFIG['CC_TYPE'] in ('clang', 'gcc'):
+ CXXFLAGS += [
+ '-Wno-sign-compare',
+ '-Wno-unused-function'
+ ]
+
+if CONFIG['TARGET_ENDIANNESS'] == 'big':
+ DEFINES['SNAPPY_IS_BIG_ENDIAN'] = 1
diff --git a/other-licenses/snappy/snappy-stubs-public.h b/other-licenses/snappy/snappy-stubs-public.h
new file mode 100644
index 0000000000..42b690094c
--- /dev/null
+++ b/other-licenses/snappy/snappy-stubs-public.h
@@ -0,0 +1,56 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: sesse@google.com (Steinar H. Gunderson)
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various type stubs for the open-source version of Snappy.
+//
+// This file cannot include config.h, as it is included from snappy.h,
+// which is a public header. Instead, snappy-stubs-public.h is generated by
+// from snappy-stubs-public.h.in at configure time.
+
+#ifndef THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+#define THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+
+#include <cstddef>
+
+#define SNAPPY_MAJOR 1
+#define SNAPPY_MINOR 1
+#define SNAPPY_PATCHLEVEL 9
+#define SNAPPY_VERSION \
+ ((SNAPPY_MAJOR << 16) | (SNAPPY_MINOR << 8) | SNAPPY_PATCHLEVEL)
+
+namespace snappy {
+
+struct iovec {
+ void* iov_base;
+ size_t iov_len;
+};
+
+} // namespace snappy
+
+#endif // THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
diff --git a/other-licenses/snappy/src/AUTHORS b/other-licenses/snappy/src/AUTHORS
new file mode 100644
index 0000000000..4858b377c7
--- /dev/null
+++ b/other-licenses/snappy/src/AUTHORS
@@ -0,0 +1 @@
+opensource@google.com
diff --git a/other-licenses/snappy/src/CONTRIBUTING.md b/other-licenses/snappy/src/CONTRIBUTING.md
new file mode 100644
index 0000000000..d0ce551527
--- /dev/null
+++ b/other-licenses/snappy/src/CONTRIBUTING.md
@@ -0,0 +1,46 @@
+# How to Contribute
+
+We'd love to accept your patches and contributions to this project. There are
+just a few small guidelines you need to follow.
+
+## Project Goals
+
+In addition to the aims listed at the top of the [README](README.md) Snappy
+explicitly supports the following:
+
+1. C++11
+2. Clang (gcc and MSVC are best-effort).
+3. Low level optimizations (e.g. assembly or equivalent intrinsics) for:
+ 1. [x86](https://en.wikipedia.org/wiki/X86)
+ 2. [x86-64](https://en.wikipedia.org/wiki/X86-64)
+ 3. ARMv7 (32-bit)
+ 4. ARMv8 (AArch64)
+4. Supports only the Snappy compression scheme as described in
+ [format_description.txt](format_description.txt).
+5. CMake for building
+
+Changes adding features or dependencies outside of the core area of focus listed
+above might not be accepted. If in doubt post a message to the
+[Snappy discussion mailing list](https://groups.google.com/g/snappy-compression).
+
+## Contributor License Agreement
+
+Contributions to this project must be accompanied by a Contributor License
+Agreement. You (or your employer) retain the copyright to your contribution,
+this simply gives us permission to use and redistribute your contributions as
+part of the project. Head over to <https://cla.developers.google.com/> to see
+your current agreements on file or to sign a new one.
+
+You generally only need to submit a CLA once, so if you've already submitted one
+(even if it was for a different project), you probably don't need to do it
+again.
+
+## Code reviews
+
+All submissions, including submissions by project members, require review. We
+use GitHub pull requests for this purpose. Consult
+[GitHub Help](https://help.github.com/articles/about-pull-requests/) for more
+information on using pull requests.
+
+Please make sure that all the automated checks (CLA, AppVeyor, Travis) pass for
+your pull requests. Pull requests whose checks fail may be ignored.
diff --git a/other-licenses/snappy/src/COPYING b/other-licenses/snappy/src/COPYING
new file mode 100644
index 0000000000..bd0e5971db
--- /dev/null
+++ b/other-licenses/snappy/src/COPYING
@@ -0,0 +1,54 @@
+Copyright 2011, Google Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+ * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+ * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+ * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+===
+
+Some of the benchmark data in testdata/ is licensed differently:
+
+ - fireworks.jpeg is Copyright 2013 Steinar H. Gunderson, and
+ is licensed under the Creative Commons Attribution 3.0 license
+ (CC-BY-3.0). See https://creativecommons.org/licenses/by/3.0/
+ for more information.
+
+ - kppkn.gtb is taken from the Gaviota chess tablebase set, and
+ is licensed under the MIT License. See
+ https://sites.google.com/site/gaviotachessengine/Home/endgame-tablebases-1
+ for more information.
+
+ - paper-100k.pdf is an excerpt (bytes 92160 to 194560) from the paper
+ “Combinatorial Modeling of Chromatin Features Quantitatively Predicts DNA
+ Replication Timing in _Drosophila_” by Federico Comoglio and Renato Paro,
+ which is licensed under the CC-BY license. See
+ http://www.ploscompbiol.org/static/license for more ifnormation.
+
+ - alice29.txt, asyoulik.txt, plrabn12.txt and lcet10.txt are from Project
+ Gutenberg. The first three have expired copyrights and are in the public
+ domain; the latter does not have expired copyright, but is still in the
+ public domain according to the license information
+ (http://www.gutenberg.org/ebooks/53).
diff --git a/other-licenses/snappy/src/NEWS b/other-licenses/snappy/src/NEWS
new file mode 100644
index 0000000000..931a5e13fd
--- /dev/null
+++ b/other-licenses/snappy/src/NEWS
@@ -0,0 +1,194 @@
+Snappy v1.1.9, May 4th 2021:
+
+ * Performance improvements.
+
+ * Google Test and Google Benchmark are now bundled in third_party/.
+
+Snappy v1.1.8, January 15th 2020:
+
+ * Small performance improvements.
+
+ * Removed snappy::string alias for std::string.
+
+ * Improved CMake configuration.
+
+Snappy v1.1.7, August 24th 2017:
+
+ * Improved CMake build support for 64-bit Linux distributions.
+
+ * MSVC builds now use MSVC-specific intrinsics that map to clzll.
+
+ * ARM64 (AArch64) builds use the code paths optimized for 64-bit processors.
+
+Snappy v1.1.6, July 12th 2017:
+
+This is a re-release of v1.1.5 with proper SONAME / SOVERSION values.
+
+Snappy v1.1.5, June 28th 2017:
+
+This release has broken SONAME / SOVERSION values. Users of snappy as a shared
+library should avoid 1.1.5 and use 1.1.6 instead. SONAME / SOVERSION errors will
+manifest as the dynamic library loader complaining that it cannot find snappy's
+shared library file (libsnappy.so / libsnappy.dylib), or that the library it
+found does not have the required version. 1.1.6 has the same code as 1.1.5, but
+carries build configuration fixes for the issues above.
+
+ * Add CMake build support. The autoconf build support is now deprecated, and
+ will be removed in the next release.
+
+ * Add AppVeyor configuration, for Windows CI coverage.
+
+ * Small performance improvement on little-endian PowerPC.
+
+ * Small performance improvement on LLVM with position-independent executables.
+
+ * Fix a few issues with various build environments.
+
+Snappy v1.1.4, January 25th 2017:
+
+ * Fix a 1% performance regression when snappy is used in PIE executables.
+
+ * Improve compression performance by 5%.
+
+ * Improve decompression performance by 20%.
+
+Snappy v1.1.3, July 6th 2015:
+
+This is the first release to be done from GitHub, which means that
+some minor things like the ChangeLog format has changed (git log
+format instead of svn log).
+
+ * Add support for Uncompress() from a Source to a Sink.
+
+ * Various minor changes to improve MSVC support; in particular,
+ the unit tests now compile and run under MSVC.
+
+
+Snappy v1.1.2, February 28th 2014:
+
+This is a maintenance release with no changes to the actual library
+source code.
+
+ * Stop distributing benchmark data files that have unclear
+ or unsuitable licensing.
+
+ * Add support for padding chunks in the framing format.
+
+
+Snappy v1.1.1, October 15th 2013:
+
+ * Add support for uncompressing to iovecs (scatter I/O).
+ The bulk of this patch was contributed by Mohit Aron.
+
+ * Speed up decompression by ~2%; much more so (~13-20%) on
+ a few benchmarks on given compilers and CPUs.
+
+ * Fix a few issues with MSVC compilation.
+
+ * Support truncated test data in the benchmark.
+
+
+Snappy v1.1.0, January 18th 2013:
+
+ * Snappy now uses 64 kB block size instead of 32 kB. On average,
+ this means it compresses about 3% denser (more so for some
+ inputs), at the same or better speeds.
+
+ * libsnappy no longer depends on iostream.
+
+ * Some small performance improvements in compression on x86
+ (0.5–1%).
+
+ * Various portability fixes for ARM-based platforms, for MSVC,
+ and for GNU/Hurd.
+
+
+Snappy v1.0.5, February 24th 2012:
+
+ * More speed improvements. Exactly how big will depend on
+ the architecture:
+
+ - 3–10% faster decompression for the base case (x86-64).
+
+ - ARMv7 and higher can now use unaligned accesses,
+ and will see about 30% faster decompression and
+ 20–40% faster compression.
+
+ - 32-bit platforms (ARM and 32-bit x86) will see 2–5%
+ faster compression.
+
+ These are all cumulative (e.g., ARM gets all three speedups).
+
+ * Fixed an issue where the unit test would crash on system
+ with less than 256 MB address space available,
+ e.g. some embedded platforms.
+
+ * Added a framing format description, for use over e.g. HTTP,
+ or for a command-line compressor. We do not have any
+ implementations of this at the current point, but there seems
+ to be enough of a general interest in the topic.
+ Also make the format description slightly clearer.
+
+ * Remove some compile-time warnings in -Wall
+ (mostly signed/unsigned comparisons), for easier embedding
+ into projects that use -Wall -Werror.
+
+
+Snappy v1.0.4, September 15th 2011:
+
+ * Speeded up the decompressor somewhat; typically about 2–8%
+ for Core i7, in 64-bit mode (comparable for Opteron).
+ Somewhat more for some tests, almost no gain for others.
+
+ * Make Snappy compile on certain platforms it didn't before
+ (Solaris with SunPro C++, HP-UX, AIX).
+
+ * Correct some minor errors in the format description.
+
+
+Snappy v1.0.3, June 2nd 2011:
+
+ * Speeded up the decompressor somewhat; about 3-6% for Core 2,
+ 6-13% for Core i7, and 5-12% for Opteron (all in 64-bit mode).
+
+ * Added compressed format documentation. This text is new,
+ but an earlier version from Zeev Tarantov was used as reference.
+
+ * Only link snappy_unittest against -lz and other autodetected
+ libraries, not libsnappy.so (which doesn't need any such dependency).
+
+ * Fixed some display issues in the microbenchmarks, one of which would
+ frequently make the test crash on GNU/Hurd.
+
+
+Snappy v1.0.2, April 29th 2011:
+
+ * Relicense to a BSD-type license.
+
+ * Added C bindings, contributed by Martin Gieseking.
+
+ * More Win32 fixes, in particular for MSVC.
+
+ * Replace geo.protodata with a newer version.
+
+ * Fix timing inaccuracies in the unit test when comparing Snappy
+ to other algorithms.
+
+
+Snappy v1.0.1, March 25th 2011:
+
+This is a maintenance release, mostly containing minor fixes.
+There is no new functionality. The most important fixes include:
+
+ * The COPYING file and all licensing headers now correctly state that
+ Snappy is licensed under the Apache 2.0 license.
+
+ * snappy_unittest should now compile natively under Windows,
+ as well as on embedded systems with no mmap().
+
+ * Various autotools nits have been fixed.
+
+
+Snappy v1.0, March 17th 2011:
+
+ * Initial version.
diff --git a/other-licenses/snappy/src/README.md b/other-licenses/snappy/src/README.md
new file mode 100644
index 0000000000..8fd7dc09ed
--- /dev/null
+++ b/other-licenses/snappy/src/README.md
@@ -0,0 +1,140 @@
+Snappy, a fast compressor/decompressor.
+
+[![Build Status](https://travis-ci.org/google/snappy.svg?branch=master)](https://travis-ci.org/google/snappy)
+[![Build status](https://ci.appveyor.com/api/projects/status/t9nubcqkwo8rw8yn/branch/master?svg=true)](https://ci.appveyor.com/project/pwnall/leveldb)
+
+Introduction
+============
+
+Snappy is a compression/decompression library. It does not aim for maximum
+compression, or compatibility with any other compression library; instead,
+it aims for very high speeds and reasonable compression. For instance,
+compared to the fastest mode of zlib, Snappy is an order of magnitude faster
+for most inputs, but the resulting compressed files are anywhere from 20% to
+100% bigger. (For more information, see "Performance", below.)
+
+Snappy has the following properties:
+
+ * Fast: Compression speeds at 250 MB/sec and beyond, with no assembler code.
+ See "Performance" below.
+ * Stable: Over the last few years, Snappy has compressed and decompressed
+ petabytes of data in Google's production environment. The Snappy bitstream
+ format is stable and will not change between versions.
+ * Robust: The Snappy decompressor is designed not to crash in the face of
+ corrupted or malicious input.
+ * Free and open source software: Snappy is licensed under a BSD-type license.
+ For more information, see the included COPYING file.
+
+Snappy has previously been called "Zippy" in some Google presentations
+and the like.
+
+
+Performance
+===========
+
+Snappy is intended to be fast. On a single core of a Core i7 processor
+in 64-bit mode, it compresses at about 250 MB/sec or more and decompresses at
+about 500 MB/sec or more. (These numbers are for the slowest inputs in our
+benchmark suite; others are much faster.) In our tests, Snappy usually
+is faster than algorithms in the same class (e.g. LZO, LZF, QuickLZ,
+etc.) while achieving comparable compression ratios.
+
+Typical compression ratios (based on the benchmark suite) are about 1.5-1.7x
+for plain text, about 2-4x for HTML, and of course 1.0x for JPEGs, PNGs and
+other already-compressed data. Similar numbers for zlib in its fastest mode
+are 2.6-2.8x, 3-7x and 1.0x, respectively. More sophisticated algorithms are
+capable of achieving yet higher compression rates, although usually at the
+expense of speed. Of course, compression ratio will vary significantly with
+the input.
+
+Although Snappy should be fairly portable, it is primarily optimized
+for 64-bit x86-compatible processors, and may run slower in other environments.
+In particular:
+
+ - Snappy uses 64-bit operations in several places to process more data at
+ once than would otherwise be possible.
+ - Snappy assumes unaligned 32 and 64-bit loads and stores are cheap.
+ On some platforms, these must be emulated with single-byte loads
+ and stores, which is much slower.
+ - Snappy assumes little-endian throughout, and needs to byte-swap data in
+ several places if running on a big-endian platform.
+
+Experience has shown that even heavily tuned code can be improved.
+Performance optimizations, whether for 64-bit x86 or other platforms,
+are of course most welcome; see "Contact", below.
+
+
+Building
+========
+
+You need the CMake version specified in [CMakeLists.txt](./CMakeLists.txt)
+or later to build:
+
+```bash
+git submodule update --init
+mkdir build
+cd build && cmake ../ && make
+```
+
+Usage
+=====
+
+Note that Snappy, both the implementation and the main interface,
+is written in C++. However, several third-party bindings to other languages
+are available; see the [home page](docs/README.md) for more information.
+Also, if you want to use Snappy from C code, you can use the included C
+bindings in snappy-c.h.
+
+To use Snappy from your own C++ program, include the file "snappy.h" from
+your calling file, and link against the compiled library.
+
+There are many ways to call Snappy, but the simplest possible is
+
+```cpp
+snappy::Compress(input.data(), input.size(), &output);
+```
+
+and similarly
+
+```cpp
+snappy::Uncompress(input.data(), input.size(), &output);
+```
+
+where "input" and "output" are both instances of std::string.
+
+There are other interfaces that are more flexible in various ways, including
+support for custom (non-array) input sources. See the header file for more
+information.
+
+
+Tests and benchmarks
+====================
+
+When you compile Snappy, the following binaries are compiled in addition to the
+library itself. You do not need them to use the compressor from your own
+library, but they are useful for Snappy development.
+
+* `snappy_benchmark` contains microbenchmarks used to tune compression and
+ decompression performance.
+* `snappy_unittests` contains unit tests, verifying correctness on your machine
+ in various scenarios.
+* `snappy_test_tool` can benchmark Snappy against a few other compression
+ libraries (zlib, LZO, LZF, and QuickLZ), if they were detected at configure
+ time. To benchmark using a given file, give the compression algorithm you want
+ to test Snappy against (e.g. --zlib) and then a list of one or more file names
+ on the command line.
+
+If you want to change or optimize Snappy, please run the tests and benchmarks to
+verify you have not broken anything.
+
+The testdata/ directory contains the files used by the microbenchmarks, which
+should provide a reasonably balanced starting point for benchmarking. (Note that
+baddata[1-3].snappy are not intended as benchmarks; they are used to verify
+correctness in the presence of corrupted data in the unit test.)
+
+
+Contact
+=======
+
+Snappy is distributed through GitHub. For the latest version and other
+information, see https://github.com/google/snappy.
diff --git a/other-licenses/snappy/src/format_description.txt b/other-licenses/snappy/src/format_description.txt
new file mode 100644
index 0000000000..20db66c1f2
--- /dev/null
+++ b/other-licenses/snappy/src/format_description.txt
@@ -0,0 +1,110 @@
+Snappy compressed format description
+Last revised: 2011-10-05
+
+
+This is not a formal specification, but should suffice to explain most
+relevant parts of how the Snappy format works. It is originally based on
+text by Zeev Tarantov.
+
+Snappy is a LZ77-type compressor with a fixed, byte-oriented encoding.
+There is no entropy encoder backend nor framing layer -- the latter is
+assumed to be handled by other parts of the system.
+
+This document only describes the format, not how the Snappy compressor nor
+decompressor actually works. The correctness of the decompressor should not
+depend on implementation details of the compressor, and vice versa.
+
+
+1. Preamble
+
+The stream starts with the uncompressed length (up to a maximum of 2^32 - 1),
+stored as a little-endian varint. Varints consist of a series of bytes,
+where the lower 7 bits are data and the upper bit is set iff there are
+more bytes to be read. In other words, an uncompressed length of 64 would
+be stored as 0x40, and an uncompressed length of 2097150 (0x1FFFFE)
+would be stored as 0xFE 0xFF 0x7F.
+
+
+2. The compressed stream itself
+
+There are two types of elements in a Snappy stream: Literals and
+copies (backreferences). There is no restriction on the order of elements,
+except that the stream naturally cannot start with a copy. (Having
+two literals in a row is never optimal from a compression point of
+view, but nevertheless fully permitted.) Each element starts with a tag byte,
+and the lower two bits of this tag byte signal what type of element will
+follow:
+
+ 00: Literal
+ 01: Copy with 1-byte offset
+ 10: Copy with 2-byte offset
+ 11: Copy with 4-byte offset
+
+The interpretation of the upper six bits are element-dependent.
+
+
+2.1. Literals (00)
+
+Literals are uncompressed data stored directly in the byte stream.
+The literal length is stored differently depending on the length
+of the literal:
+
+ - For literals up to and including 60 bytes in length, the upper
+ six bits of the tag byte contain (len-1). The literal follows
+ immediately thereafter in the bytestream.
+ - For longer literals, the (len-1) value is stored after the tag byte,
+ little-endian. The upper six bits of the tag byte describe how
+ many bytes are used for the length; 60, 61, 62 or 63 for
+ 1-4 bytes, respectively. The literal itself follows after the
+ length.
+
+
+2.2. Copies
+
+Copies are references back into previous decompressed data, telling
+the decompressor to reuse data it has previously decoded.
+They encode two values: The _offset_, saying how many bytes back
+from the current position to read, and the _length_, how many bytes
+to copy. Offsets of zero can be encoded, but are not legal;
+similarly, it is possible to encode backreferences that would
+go past the end of the block (offset > current decompressed position),
+which is also nonsensical and thus not allowed.
+
+As in most LZ77-based compressors, the length can be larger than the offset,
+yielding a form of run-length encoding (RLE). For instance,
+"xababab" could be encoded as
+
+ <literal: "xab"> <copy: offset=2 length=4>
+
+Note that since the current Snappy compressor works in 32 kB
+blocks and does not do matching across blocks, it will never produce
+a bitstream with offsets larger than about 32768. However, the
+decompressor should not rely on this, as it may change in the future.
+
+There are several different kinds of copy elements, depending on
+the amount of bytes to be copied (length), and how far back the
+data to be copied is (offset).
+
+
+2.2.1. Copy with 1-byte offset (01)
+
+These elements can encode lengths between [4..11] bytes and offsets
+between [0..2047] bytes. (len-4) occupies three bits and is stored
+in bits [2..4] of the tag byte. The offset occupies 11 bits, of which the
+upper three are stored in the upper three bits ([5..7]) of the tag byte,
+and the lower eight are stored in a byte following the tag byte.
+
+
+2.2.2. Copy with 2-byte offset (10)
+
+These elements can encode lengths between [1..64] and offsets from
+[0..65535]. (len-1) occupies six bits and is stored in the upper
+six bits ([2..7]) of the tag byte. The offset is stored as a
+little-endian 16-bit integer in the two bytes following the tag byte.
+
+
+2.2.3. Copy with 4-byte offset (11)
+
+These are like the copies with 2-byte offsets (see previous subsection),
+except that the offset is stored as a 32-bit integer instead of a
+16-bit integer (and thus will occupy four bytes).
diff --git a/other-licenses/snappy/src/framing_format.txt b/other-licenses/snappy/src/framing_format.txt
new file mode 100644
index 0000000000..9764e83de6
--- /dev/null
+++ b/other-licenses/snappy/src/framing_format.txt
@@ -0,0 +1,135 @@
+Snappy framing format description
+Last revised: 2013-10-25
+
+This format decribes a framing format for Snappy, allowing compressing to
+files or streams that can then more easily be decompressed without having
+to hold the entire stream in memory. It also provides data checksums to
+help verify integrity. It does not provide metadata checksums, so it does
+not protect against e.g. all forms of truncations.
+
+Implementation of the framing format is optional for Snappy compressors and
+decompressor; it is not part of the Snappy core specification.
+
+
+1. General structure
+
+The file consists solely of chunks, lying back-to-back with no padding
+in between. Each chunk consists first a single byte of chunk identifier,
+then a three-byte little-endian length of the chunk in bytes (from 0 to
+16777215, inclusive), and then the data if any. The four bytes of chunk
+header is not counted in the data length.
+
+The different chunk types are listed below. The first chunk must always
+be the stream identifier chunk (see section 4.1, below). The stream
+ends when the file ends -- there is no explicit end-of-file marker.
+
+
+2. File type identification
+
+The following identifiers for this format are recommended where appropriate.
+However, note that none have been registered officially, so this is only to
+be taken as a guideline. We use "Snappy framed" to distinguish between this
+format and raw Snappy data.
+
+ File extension: .sz
+ MIME type: application/x-snappy-framed
+ HTTP Content-Encoding: x-snappy-framed
+
+
+3. Checksum format
+
+Some chunks have data protected by a checksum (the ones that do will say so
+explicitly). The checksums are always masked CRC-32Cs.
+
+A description of CRC-32C can be found in RFC 3720, section 12.1, with
+examples in section B.4.
+
+Checksums are not stored directly, but masked, as checksumming data and
+then its own checksum can be problematic. The masking is the same as used
+in Apache Hadoop: Rotate the checksum by 15 bits, then add the constant
+0xa282ead8 (using wraparound as normal for unsigned integers). This is
+equivalent to the following C code:
+
+ uint32_t mask_checksum(uint32_t x) {
+ return ((x >> 15) | (x << 17)) + 0xa282ead8;
+ }
+
+Note that the masking is reversible.
+
+The checksum is always stored as a four bytes long integer, in little-endian.
+
+
+4. Chunk types
+
+The currently supported chunk types are described below. The list may
+be extended in the future.
+
+
+4.1. Stream identifier (chunk type 0xff)
+
+The stream identifier is always the first element in the stream.
+It is exactly six bytes long and contains "sNaPpY" in ASCII. This means that
+a valid Snappy framed stream always starts with the bytes
+
+ 0xff 0x06 0x00 0x00 0x73 0x4e 0x61 0x50 0x70 0x59
+
+The stream identifier chunk can come multiple times in the stream besides
+the first; if such a chunk shows up, it should simply be ignored, assuming
+it has the right length and contents. This allows for easy concatenation of
+compressed files without the need for re-framing.
+
+
+4.2. Compressed data (chunk type 0x00)
+
+Compressed data chunks contain a normal Snappy compressed bitstream;
+see the compressed format specification. The compressed data is preceded by
+the CRC-32C (see section 3) of the _uncompressed_ data.
+
+Note that the data portion of the chunk, i.e., the compressed contents,
+can be at most 16777211 bytes (2^24 - 1, minus the checksum).
+However, we place an additional restriction that the uncompressed data
+in a chunk must be no longer than 65536 bytes. This allows consumers to
+easily use small fixed-size buffers.
+
+
+4.3. Uncompressed data (chunk type 0x01)
+
+Uncompressed data chunks allow a compressor to send uncompressed,
+raw data; this is useful if, for instance, uncompressible or
+near-incompressible data is detected, and faster decompression is desired.
+
+As in the compressed chunks, the data is preceded by its own masked
+CRC-32C (see section 3).
+
+An uncompressed data chunk, like compressed data chunks, should contain
+no more than 65536 data bytes, so the maximum legal chunk length with the
+checksum is 65540.
+
+
+4.4. Padding (chunk type 0xfe)
+
+Padding chunks allow a compressor to increase the size of the data stream
+so that it complies with external demands, e.g. that the total number of
+bytes is a multiple of some value.
+
+All bytes of the padding chunk, except the chunk byte itself and the length,
+should be zero, but decompressors must not try to interpret or verify the
+padding data in any way.
+
+
+4.5. Reserved unskippable chunks (chunk types 0x02-0x7f)
+
+These are reserved for future expansion. A decoder that sees such a chunk
+should immediately return an error, as it must assume it cannot decode the
+stream correctly.
+
+Future versions of this specification may define meanings for these chunks.
+
+
+4.6. Reserved skippable chunks (chunk types 0x80-0xfd)
+
+These are also reserved for future expansion, but unlike the chunks
+described in 4.5, a decoder seeing these must skip them and continue
+decoding.
+
+Future versions of this specification may define meanings for these chunks.
diff --git a/other-licenses/snappy/src/snappy-c.cc b/other-licenses/snappy/src/snappy-c.cc
new file mode 100644
index 0000000000..473a0b0978
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-c.cc
@@ -0,0 +1,90 @@
+// Copyright 2011 Martin Gieseking <martin.gieseking@uos.de>.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "snappy.h"
+#include "snappy-c.h"
+
+extern "C" {
+
+snappy_status snappy_compress(const char* input,
+ size_t input_length,
+ char* compressed,
+ size_t *compressed_length) {
+ if (*compressed_length < snappy_max_compressed_length(input_length)) {
+ return SNAPPY_BUFFER_TOO_SMALL;
+ }
+ snappy::RawCompress(input, input_length, compressed, compressed_length);
+ return SNAPPY_OK;
+}
+
+snappy_status snappy_uncompress(const char* compressed,
+ size_t compressed_length,
+ char* uncompressed,
+ size_t* uncompressed_length) {
+ size_t real_uncompressed_length;
+ if (!snappy::GetUncompressedLength(compressed,
+ compressed_length,
+ &real_uncompressed_length)) {
+ return SNAPPY_INVALID_INPUT;
+ }
+ if (*uncompressed_length < real_uncompressed_length) {
+ return SNAPPY_BUFFER_TOO_SMALL;
+ }
+ if (!snappy::RawUncompress(compressed, compressed_length, uncompressed)) {
+ return SNAPPY_INVALID_INPUT;
+ }
+ *uncompressed_length = real_uncompressed_length;
+ return SNAPPY_OK;
+}
+
+size_t snappy_max_compressed_length(size_t source_length) {
+ return snappy::MaxCompressedLength(source_length);
+}
+
+snappy_status snappy_uncompressed_length(const char *compressed,
+ size_t compressed_length,
+ size_t *result) {
+ if (snappy::GetUncompressedLength(compressed,
+ compressed_length,
+ result)) {
+ return SNAPPY_OK;
+ } else {
+ return SNAPPY_INVALID_INPUT;
+ }
+}
+
+snappy_status snappy_validate_compressed_buffer(const char *compressed,
+ size_t compressed_length) {
+ if (snappy::IsValidCompressedBuffer(compressed, compressed_length)) {
+ return SNAPPY_OK;
+ } else {
+ return SNAPPY_INVALID_INPUT;
+ }
+}
+
+} // extern "C"
diff --git a/other-licenses/snappy/src/snappy-c.h b/other-licenses/snappy/src/snappy-c.h
new file mode 100644
index 0000000000..32aa0c6b8b
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-c.h
@@ -0,0 +1,138 @@
+/*
+ * Copyright 2011 Martin Gieseking <martin.gieseking@uos.de>.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ * * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ * * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Plain C interface (a wrapper around the C++ implementation).
+ */
+
+#ifndef THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_C_H_
+#define THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_C_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>
+
+/*
+ * Return values; see the documentation for each function to know
+ * what each can return.
+ */
+typedef enum {
+ SNAPPY_OK = 0,
+ SNAPPY_INVALID_INPUT = 1,
+ SNAPPY_BUFFER_TOO_SMALL = 2
+} snappy_status;
+
+/*
+ * Takes the data stored in "input[0..input_length-1]" and stores
+ * it in the array pointed to by "compressed".
+ *
+ * <compressed_length> signals the space available in "compressed".
+ * If it is not at least equal to "snappy_max_compressed_length(input_length)",
+ * SNAPPY_BUFFER_TOO_SMALL is returned. After successful compression,
+ * <compressed_length> contains the true length of the compressed output,
+ * and SNAPPY_OK is returned.
+ *
+ * Example:
+ * size_t output_length = snappy_max_compressed_length(input_length);
+ * char* output = (char*)malloc(output_length);
+ * if (snappy_compress(input, input_length, output, &output_length)
+ * == SNAPPY_OK) {
+ * ... Process(output, output_length) ...
+ * }
+ * free(output);
+ */
+snappy_status snappy_compress(const char* input,
+ size_t input_length,
+ char* compressed,
+ size_t* compressed_length);
+
+/*
+ * Given data in "compressed[0..compressed_length-1]" generated by
+ * calling the snappy_compress routine, this routine stores
+ * the uncompressed data to
+ * uncompressed[0..uncompressed_length-1].
+ * Returns failure (a value not equal to SNAPPY_OK) if the message
+ * is corrupted and could not be decrypted.
+ *
+ * <uncompressed_length> signals the space available in "uncompressed".
+ * If it is not at least equal to the value returned by
+ * snappy_uncompressed_length for this stream, SNAPPY_BUFFER_TOO_SMALL
+ * is returned. After successful decompression, <uncompressed_length>
+ * contains the true length of the decompressed output.
+ *
+ * Example:
+ * size_t output_length;
+ * if (snappy_uncompressed_length(input, input_length, &output_length)
+ * != SNAPPY_OK) {
+ * ... fail ...
+ * }
+ * char* output = (char*)malloc(output_length);
+ * if (snappy_uncompress(input, input_length, output, &output_length)
+ * == SNAPPY_OK) {
+ * ... Process(output, output_length) ...
+ * }
+ * free(output);
+ */
+snappy_status snappy_uncompress(const char* compressed,
+ size_t compressed_length,
+ char* uncompressed,
+ size_t* uncompressed_length);
+
+/*
+ * Returns the maximal size of the compressed representation of
+ * input data that is "source_length" bytes in length.
+ */
+size_t snappy_max_compressed_length(size_t source_length);
+
+/*
+ * REQUIRES: "compressed[]" was produced by snappy_compress()
+ * Returns SNAPPY_OK and stores the length of the uncompressed data in
+ * *result normally. Returns SNAPPY_INVALID_INPUT on parsing error.
+ * This operation takes O(1) time.
+ */
+snappy_status snappy_uncompressed_length(const char* compressed,
+ size_t compressed_length,
+ size_t* result);
+
+/*
+ * Check if the contents of "compressed[]" can be uncompressed successfully.
+ * Does not return the uncompressed data; if so, returns SNAPPY_OK,
+ * or if not, returns SNAPPY_INVALID_INPUT.
+ * Takes time proportional to compressed_length, but is usually at least a
+ * factor of four faster than actual decompression.
+ */
+snappy_status snappy_validate_compressed_buffer(const char* compressed,
+ size_t compressed_length);
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif /* THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_C_H_ */
diff --git a/other-licenses/snappy/src/snappy-internal.h b/other-licenses/snappy/src/snappy-internal.h
new file mode 100644
index 0000000000..720ccd8282
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-internal.h
@@ -0,0 +1,317 @@
+// Copyright 2008 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Internals shared between the Snappy implementation and its unittest.
+
+#ifndef THIRD_PARTY_SNAPPY_SNAPPY_INTERNAL_H_
+#define THIRD_PARTY_SNAPPY_SNAPPY_INTERNAL_H_
+
+#include "snappy-stubs-internal.h"
+
+namespace snappy {
+namespace internal {
+
+// Working memory performs a single allocation to hold all scratch space
+// required for compression.
+class WorkingMemory {
+ public:
+ explicit WorkingMemory(size_t input_size);
+ ~WorkingMemory();
+
+ // Allocates and clears a hash table using memory in "*this",
+ // stores the number of buckets in "*table_size" and returns a pointer to
+ // the base of the hash table.
+ uint16_t* GetHashTable(size_t fragment_size, int* table_size) const;
+ char* GetScratchInput() const { return input_; }
+ char* GetScratchOutput() const { return output_; }
+
+ private:
+ char* mem_; // the allocated memory, never nullptr
+ size_t size_; // the size of the allocated memory, never 0
+ uint16_t* table_; // the pointer to the hashtable
+ char* input_; // the pointer to the input scratch buffer
+ char* output_; // the pointer to the output scratch buffer
+
+ // No copying
+ WorkingMemory(const WorkingMemory&);
+ void operator=(const WorkingMemory&);
+};
+
+// Flat array compression that does not emit the "uncompressed length"
+// prefix. Compresses "input" string to the "*op" buffer.
+//
+// REQUIRES: "input_length <= kBlockSize"
+// REQUIRES: "op" points to an array of memory that is at least
+// "MaxCompressedLength(input_length)" in size.
+// REQUIRES: All elements in "table[0..table_size-1]" are initialized to zero.
+// REQUIRES: "table_size" is a power of two
+//
+// Returns an "end" pointer into "op" buffer.
+// "end - op" is the compressed size of "input".
+char* CompressFragment(const char* input,
+ size_t input_length,
+ char* op,
+ uint16_t* table,
+ const int table_size);
+
+// Find the largest n such that
+//
+// s1[0,n-1] == s2[0,n-1]
+// and n <= (s2_limit - s2).
+//
+// Return make_pair(n, n < 8).
+// Does not read *s2_limit or beyond.
+// Does not read *(s1 + (s2_limit - s2)) or beyond.
+// Requires that s2_limit >= s2.
+//
+// In addition populate *data with the next 5 bytes from the end of the match.
+// This is only done if 8 bytes are available (s2_limit - s2 >= 8). The point is
+// that on some arch's this can be done faster in this routine than subsequent
+// loading from s2 + n.
+//
+// Separate implementation for 64-bit, little-endian cpus.
+#if !defined(SNAPPY_IS_BIG_ENDIAN) && \
+ (defined(__x86_64__) || defined(_M_X64) || defined(ARCH_PPC) || defined(ARCH_ARM))
+static inline std::pair<size_t, bool> FindMatchLength(const char* s1,
+ const char* s2,
+ const char* s2_limit,
+ uint64_t* data) {
+ assert(s2_limit >= s2);
+ size_t matched = 0;
+
+ // This block isn't necessary for correctness; we could just start looping
+ // immediately. As an optimization though, it is useful. It creates some not
+ // uncommon code paths that determine, without extra effort, whether the match
+ // length is less than 8. In short, we are hoping to avoid a conditional
+ // branch, and perhaps get better code layout from the C++ compiler.
+ if (SNAPPY_PREDICT_TRUE(s2 <= s2_limit - 16)) {
+ uint64_t a1 = UNALIGNED_LOAD64(s1);
+ uint64_t a2 = UNALIGNED_LOAD64(s2);
+ if (SNAPPY_PREDICT_TRUE(a1 != a2)) {
+ // This code is critical for performance. The reason is that it determines
+ // how much to advance `ip` (s2). This obviously depends on both the loads
+ // from the `candidate` (s1) and `ip`. Furthermore the next `candidate`
+ // depends on the advanced `ip` calculated here through a load, hash and
+ // new candidate hash lookup (a lot of cycles). This makes s1 (ie.
+ // `candidate`) the variable that limits throughput. This is the reason we
+ // go through hoops to have this function update `data` for the next iter.
+ // The straightforward code would use *data, given by
+ //
+ // *data = UNALIGNED_LOAD64(s2 + matched_bytes) (Latency of 5 cycles),
+ //
+ // as input for the hash table lookup to find next candidate. However
+ // this forces the load on the data dependency chain of s1, because
+ // matched_bytes directly depends on s1. However matched_bytes is 0..7, so
+ // we can also calculate *data by
+ //
+ // *data = AlignRight(UNALIGNED_LOAD64(s2), UNALIGNED_LOAD64(s2 + 8),
+ // matched_bytes);
+ //
+ // The loads do not depend on s1 anymore and are thus off the bottleneck.
+ // The straightforward implementation on x86_64 would be to use
+ //
+ // shrd rax, rdx, cl (cl being matched_bytes * 8)
+ //
+ // unfortunately shrd with a variable shift has a 4 cycle latency. So this
+ // only wins 1 cycle. The BMI2 shrx instruction is a 1 cycle variable
+ // shift instruction but can only shift 64 bits. If we focus on just
+ // obtaining the least significant 4 bytes, we can obtain this by
+ //
+ // *data = ConditionalMove(matched_bytes < 4, UNALIGNED_LOAD64(s2),
+ // UNALIGNED_LOAD64(s2 + 4) >> ((matched_bytes & 3) * 8);
+ //
+ // Writen like above this is not a big win, the conditional move would be
+ // a cmp followed by a cmov (2 cycles) followed by a shift (1 cycle).
+ // However matched_bytes < 4 is equal to
+ // static_cast<uint32_t>(xorval) != 0. Writen that way, the conditional
+ // move (2 cycles) can execute in parallel with FindLSBSetNonZero64
+ // (tzcnt), which takes 3 cycles.
+ uint64_t xorval = a1 ^ a2;
+ int shift = Bits::FindLSBSetNonZero64(xorval);
+ size_t matched_bytes = shift >> 3;
+#ifndef __x86_64__
+ *data = UNALIGNED_LOAD64(s2 + matched_bytes);
+#else
+ // Ideally this would just be
+ //
+ // a2 = static_cast<uint32_t>(xorval) == 0 ? a3 : a2;
+ //
+ // However clang correctly infers that the above statement participates on
+ // a critical data dependency chain and thus, unfortunately, refuses to
+ // use a conditional move (it's tuned to cut data dependencies). In this
+ // case there is a longer parallel chain anyway AND this will be fairly
+ // unpredictable.
+ uint64_t a3 = UNALIGNED_LOAD64(s2 + 4);
+ asm("testl %k2, %k2\n\t"
+ "cmovzq %1, %0\n\t"
+ : "+r"(a2)
+ : "r"(a3), "r"(xorval));
+ *data = a2 >> (shift & (3 * 8));
+#endif
+ return std::pair<size_t, bool>(matched_bytes, true);
+ } else {
+ matched = 8;
+ s2 += 8;
+ }
+ }
+
+ // Find out how long the match is. We loop over the data 64 bits at a
+ // time until we find a 64-bit block that doesn't match; then we find
+ // the first non-matching bit and use that to calculate the total
+ // length of the match.
+ while (SNAPPY_PREDICT_TRUE(s2 <= s2_limit - 16)) {
+ uint64_t a1 = UNALIGNED_LOAD64(s1 + matched);
+ uint64_t a2 = UNALIGNED_LOAD64(s2);
+ if (a1 == a2) {
+ s2 += 8;
+ matched += 8;
+ } else {
+ uint64_t xorval = a1 ^ a2;
+ int shift = Bits::FindLSBSetNonZero64(xorval);
+ size_t matched_bytes = shift >> 3;
+#ifndef __x86_64__
+ *data = UNALIGNED_LOAD64(s2 + matched_bytes);
+#else
+ uint64_t a3 = UNALIGNED_LOAD64(s2 + 4);
+ asm("testl %k2, %k2\n\t"
+ "cmovzq %1, %0\n\t"
+ : "+r"(a2)
+ : "r"(a3), "r"(xorval));
+ *data = a2 >> (shift & (3 * 8));
+#endif
+ matched += matched_bytes;
+ assert(matched >= 8);
+ return std::pair<size_t, bool>(matched, false);
+ }
+ }
+ while (SNAPPY_PREDICT_TRUE(s2 < s2_limit)) {
+ if (s1[matched] == *s2) {
+ ++s2;
+ ++matched;
+ } else {
+ if (s2 <= s2_limit - 8) {
+ *data = UNALIGNED_LOAD64(s2);
+ }
+ return std::pair<size_t, bool>(matched, matched < 8);
+ }
+ }
+ return std::pair<size_t, bool>(matched, matched < 8);
+}
+#else
+static inline std::pair<size_t, bool> FindMatchLength(const char* s1,
+ const char* s2,
+ const char* s2_limit,
+ uint64_t* data) {
+ // Implementation based on the x86-64 version, above.
+ assert(s2_limit >= s2);
+ int matched = 0;
+
+ while (s2 <= s2_limit - 4 &&
+ UNALIGNED_LOAD32(s2) == UNALIGNED_LOAD32(s1 + matched)) {
+ s2 += 4;
+ matched += 4;
+ }
+ if (LittleEndian::IsLittleEndian() && s2 <= s2_limit - 4) {
+ uint32_t x = UNALIGNED_LOAD32(s2) ^ UNALIGNED_LOAD32(s1 + matched);
+ int matching_bits = Bits::FindLSBSetNonZero(x);
+ matched += matching_bits >> 3;
+ s2 += matching_bits >> 3;
+ } else {
+ while ((s2 < s2_limit) && (s1[matched] == *s2)) {
+ ++s2;
+ ++matched;
+ }
+ }
+ if (s2 <= s2_limit - 8) *data = LittleEndian::Load64(s2);
+ return std::pair<size_t, bool>(matched, matched < 8);
+}
+#endif
+
+// Lookup tables for decompression code. Give --snappy_dump_decompression_table
+// to the unit test to recompute char_table.
+
+enum {
+ LITERAL = 0,
+ COPY_1_BYTE_OFFSET = 1, // 3 bit length + 3 bits of offset in opcode
+ COPY_2_BYTE_OFFSET = 2,
+ COPY_4_BYTE_OFFSET = 3
+};
+static const int kMaximumTagLength = 5; // COPY_4_BYTE_OFFSET plus the actual offset.
+
+// Data stored per entry in lookup table:
+// Range Bits-used Description
+// ------------------------------------
+// 1..64 0..7 Literal/copy length encoded in opcode byte
+// 0..7 8..10 Copy offset encoded in opcode byte / 256
+// 0..4 11..13 Extra bytes after opcode
+//
+// We use eight bits for the length even though 7 would have sufficed
+// because of efficiency reasons:
+// (1) Extracting a byte is faster than a bit-field
+// (2) It properly aligns copy offset so we do not need a <<8
+static constexpr uint16_t char_table[256] = {
+ // clang-format off
+ 0x0001, 0x0804, 0x1001, 0x2001, 0x0002, 0x0805, 0x1002, 0x2002,
+ 0x0003, 0x0806, 0x1003, 0x2003, 0x0004, 0x0807, 0x1004, 0x2004,
+ 0x0005, 0x0808, 0x1005, 0x2005, 0x0006, 0x0809, 0x1006, 0x2006,
+ 0x0007, 0x080a, 0x1007, 0x2007, 0x0008, 0x080b, 0x1008, 0x2008,
+ 0x0009, 0x0904, 0x1009, 0x2009, 0x000a, 0x0905, 0x100a, 0x200a,
+ 0x000b, 0x0906, 0x100b, 0x200b, 0x000c, 0x0907, 0x100c, 0x200c,
+ 0x000d, 0x0908, 0x100d, 0x200d, 0x000e, 0x0909, 0x100e, 0x200e,
+ 0x000f, 0x090a, 0x100f, 0x200f, 0x0010, 0x090b, 0x1010, 0x2010,
+ 0x0011, 0x0a04, 0x1011, 0x2011, 0x0012, 0x0a05, 0x1012, 0x2012,
+ 0x0013, 0x0a06, 0x1013, 0x2013, 0x0014, 0x0a07, 0x1014, 0x2014,
+ 0x0015, 0x0a08, 0x1015, 0x2015, 0x0016, 0x0a09, 0x1016, 0x2016,
+ 0x0017, 0x0a0a, 0x1017, 0x2017, 0x0018, 0x0a0b, 0x1018, 0x2018,
+ 0x0019, 0x0b04, 0x1019, 0x2019, 0x001a, 0x0b05, 0x101a, 0x201a,
+ 0x001b, 0x0b06, 0x101b, 0x201b, 0x001c, 0x0b07, 0x101c, 0x201c,
+ 0x001d, 0x0b08, 0x101d, 0x201d, 0x001e, 0x0b09, 0x101e, 0x201e,
+ 0x001f, 0x0b0a, 0x101f, 0x201f, 0x0020, 0x0b0b, 0x1020, 0x2020,
+ 0x0021, 0x0c04, 0x1021, 0x2021, 0x0022, 0x0c05, 0x1022, 0x2022,
+ 0x0023, 0x0c06, 0x1023, 0x2023, 0x0024, 0x0c07, 0x1024, 0x2024,
+ 0x0025, 0x0c08, 0x1025, 0x2025, 0x0026, 0x0c09, 0x1026, 0x2026,
+ 0x0027, 0x0c0a, 0x1027, 0x2027, 0x0028, 0x0c0b, 0x1028, 0x2028,
+ 0x0029, 0x0d04, 0x1029, 0x2029, 0x002a, 0x0d05, 0x102a, 0x202a,
+ 0x002b, 0x0d06, 0x102b, 0x202b, 0x002c, 0x0d07, 0x102c, 0x202c,
+ 0x002d, 0x0d08, 0x102d, 0x202d, 0x002e, 0x0d09, 0x102e, 0x202e,
+ 0x002f, 0x0d0a, 0x102f, 0x202f, 0x0030, 0x0d0b, 0x1030, 0x2030,
+ 0x0031, 0x0e04, 0x1031, 0x2031, 0x0032, 0x0e05, 0x1032, 0x2032,
+ 0x0033, 0x0e06, 0x1033, 0x2033, 0x0034, 0x0e07, 0x1034, 0x2034,
+ 0x0035, 0x0e08, 0x1035, 0x2035, 0x0036, 0x0e09, 0x1036, 0x2036,
+ 0x0037, 0x0e0a, 0x1037, 0x2037, 0x0038, 0x0e0b, 0x1038, 0x2038,
+ 0x0039, 0x0f04, 0x1039, 0x2039, 0x003a, 0x0f05, 0x103a, 0x203a,
+ 0x003b, 0x0f06, 0x103b, 0x203b, 0x003c, 0x0f07, 0x103c, 0x203c,
+ 0x0801, 0x0f08, 0x103d, 0x203d, 0x1001, 0x0f09, 0x103e, 0x203e,
+ 0x1801, 0x0f0a, 0x103f, 0x203f, 0x2001, 0x0f0b, 0x1040, 0x2040,
+ // clang-format on
+};
+
+} // end namespace internal
+} // end namespace snappy
+
+#endif // THIRD_PARTY_SNAPPY_SNAPPY_INTERNAL_H_
diff --git a/other-licenses/snappy/src/snappy-sinksource.cc b/other-licenses/snappy/src/snappy-sinksource.cc
new file mode 100644
index 0000000000..8214964a7e
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-sinksource.cc
@@ -0,0 +1,121 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <stddef.h>
+#include <cstring>
+
+#include "snappy-sinksource.h"
+
+namespace snappy {
+
+Source::~Source() = default;
+
+Sink::~Sink() = default;
+
+char* Sink::GetAppendBuffer(size_t length, char* scratch) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)length;
+
+ return scratch;
+}
+
+char* Sink::GetAppendBufferVariable(
+ size_t min_size, size_t desired_size_hint, char* scratch,
+ size_t scratch_size, size_t* allocated_size) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)min_size;
+ (void)desired_size_hint;
+
+ *allocated_size = scratch_size;
+ return scratch;
+}
+
+void Sink::AppendAndTakeOwnership(
+ char* bytes, size_t n,
+ void (*deleter)(void*, const char*, size_t),
+ void *deleter_arg) {
+ Append(bytes, n);
+ (*deleter)(deleter_arg, bytes, n);
+}
+
+ByteArraySource::~ByteArraySource() = default;
+
+size_t ByteArraySource::Available() const { return left_; }
+
+const char* ByteArraySource::Peek(size_t* len) {
+ *len = left_;
+ return ptr_;
+}
+
+void ByteArraySource::Skip(size_t n) {
+ left_ -= n;
+ ptr_ += n;
+}
+
+UncheckedByteArraySink::~UncheckedByteArraySink() { }
+
+void UncheckedByteArraySink::Append(const char* data, size_t n) {
+ // Do no copying if the caller filled in the result of GetAppendBuffer()
+ if (data != dest_) {
+ std::memcpy(dest_, data, n);
+ }
+ dest_ += n;
+}
+
+char* UncheckedByteArraySink::GetAppendBuffer(size_t len, char* scratch) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)len;
+ (void)scratch;
+
+ return dest_;
+}
+
+void UncheckedByteArraySink::AppendAndTakeOwnership(
+ char* bytes, size_t n,
+ void (*deleter)(void*, const char*, size_t),
+ void *deleter_arg) {
+ if (bytes != dest_) {
+ std::memcpy(dest_, bytes, n);
+ (*deleter)(deleter_arg, bytes, n);
+ }
+ dest_ += n;
+}
+
+char* UncheckedByteArraySink::GetAppendBufferVariable(
+ size_t min_size, size_t desired_size_hint, char* scratch,
+ size_t scratch_size, size_t* allocated_size) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)min_size;
+ (void)scratch;
+ (void)scratch_size;
+
+ *allocated_size = desired_size_hint;
+ return dest_;
+}
+
+} // namespace snappy
diff --git a/other-licenses/snappy/src/snappy-sinksource.h b/other-licenses/snappy/src/snappy-sinksource.h
new file mode 100644
index 0000000000..3c74e1bb6e
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-sinksource.h
@@ -0,0 +1,182 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef THIRD_PARTY_SNAPPY_SNAPPY_SINKSOURCE_H_
+#define THIRD_PARTY_SNAPPY_SNAPPY_SINKSOURCE_H_
+
+#include <stddef.h>
+
+namespace snappy {
+
+// A Sink is an interface that consumes a sequence of bytes.
+class Sink {
+ public:
+ Sink() { }
+ virtual ~Sink();
+
+ // Append "bytes[0,n-1]" to this.
+ virtual void Append(const char* bytes, size_t n) = 0;
+
+ // Returns a writable buffer of the specified length for appending.
+ // May return a pointer to the caller-owned scratch buffer which
+ // must have at least the indicated length. The returned buffer is
+ // only valid until the next operation on this Sink.
+ //
+ // After writing at most "length" bytes, call Append() with the
+ // pointer returned from this function and the number of bytes
+ // written. Many Append() implementations will avoid copying
+ // bytes if this function returned an internal buffer.
+ //
+ // If a non-scratch buffer is returned, the caller may only pass a
+ // prefix of it to Append(). That is, it is not correct to pass an
+ // interior pointer of the returned array to Append().
+ //
+ // The default implementation always returns the scratch buffer.
+ virtual char* GetAppendBuffer(size_t length, char* scratch);
+
+ // For higher performance, Sink implementations can provide custom
+ // AppendAndTakeOwnership() and GetAppendBufferVariable() methods.
+ // These methods can reduce the number of copies done during
+ // compression/decompression.
+
+ // Append "bytes[0,n-1] to the sink. Takes ownership of "bytes"
+ // and calls the deleter function as (*deleter)(deleter_arg, bytes, n)
+ // to free the buffer. deleter function must be non NULL.
+ //
+ // The default implementation just calls Append and frees "bytes".
+ // Other implementations may avoid a copy while appending the buffer.
+ virtual void AppendAndTakeOwnership(
+ char* bytes, size_t n, void (*deleter)(void*, const char*, size_t),
+ void *deleter_arg);
+
+ // Returns a writable buffer for appending and writes the buffer's capacity to
+ // *allocated_size. Guarantees *allocated_size >= min_size.
+ // May return a pointer to the caller-owned scratch buffer which must have
+ // scratch_size >= min_size.
+ //
+ // The returned buffer is only valid until the next operation
+ // on this ByteSink.
+ //
+ // After writing at most *allocated_size bytes, call Append() with the
+ // pointer returned from this function and the number of bytes written.
+ // Many Append() implementations will avoid copying bytes if this function
+ // returned an internal buffer.
+ //
+ // If the sink implementation allocates or reallocates an internal buffer,
+ // it should use the desired_size_hint if appropriate. If a caller cannot
+ // provide a reasonable guess at the desired capacity, it should set
+ // desired_size_hint = 0.
+ //
+ // If a non-scratch buffer is returned, the caller may only pass
+ // a prefix to it to Append(). That is, it is not correct to pass an
+ // interior pointer to Append().
+ //
+ // The default implementation always returns the scratch buffer.
+ virtual char* GetAppendBufferVariable(
+ size_t min_size, size_t desired_size_hint, char* scratch,
+ size_t scratch_size, size_t* allocated_size);
+
+ private:
+ // No copying
+ Sink(const Sink&);
+ void operator=(const Sink&);
+};
+
+// A Source is an interface that yields a sequence of bytes
+class Source {
+ public:
+ Source() { }
+ virtual ~Source();
+
+ // Return the number of bytes left to read from the source
+ virtual size_t Available() const = 0;
+
+ // Peek at the next flat region of the source. Does not reposition
+ // the source. The returned region is empty iff Available()==0.
+ //
+ // Returns a pointer to the beginning of the region and store its
+ // length in *len.
+ //
+ // The returned region is valid until the next call to Skip() or
+ // until this object is destroyed, whichever occurs first.
+ //
+ // The returned region may be larger than Available() (for example
+ // if this ByteSource is a view on a substring of a larger source).
+ // The caller is responsible for ensuring that it only reads the
+ // Available() bytes.
+ virtual const char* Peek(size_t* len) = 0;
+
+ // Skip the next n bytes. Invalidates any buffer returned by
+ // a previous call to Peek().
+ // REQUIRES: Available() >= n
+ virtual void Skip(size_t n) = 0;
+
+ private:
+ // No copying
+ Source(const Source&);
+ void operator=(const Source&);
+};
+
+// A Source implementation that yields the contents of a flat array
+class ByteArraySource : public Source {
+ public:
+ ByteArraySource(const char* p, size_t n) : ptr_(p), left_(n) { }
+ ~ByteArraySource() override;
+ size_t Available() const override;
+ const char* Peek(size_t* len) override;
+ void Skip(size_t n) override;
+ private:
+ const char* ptr_;
+ size_t left_;
+};
+
+// A Sink implementation that writes to a flat array without any bound checks.
+class UncheckedByteArraySink : public Sink {
+ public:
+ explicit UncheckedByteArraySink(char* dest) : dest_(dest) { }
+ ~UncheckedByteArraySink() override;
+ void Append(const char* data, size_t n) override;
+ char* GetAppendBuffer(size_t len, char* scratch) override;
+ char* GetAppendBufferVariable(
+ size_t min_size, size_t desired_size_hint, char* scratch,
+ size_t scratch_size, size_t* allocated_size) override;
+ void AppendAndTakeOwnership(
+ char* bytes, size_t n, void (*deleter)(void*, const char*, size_t),
+ void *deleter_arg) override;
+
+ // Return the current output pointer so that a caller can see how
+ // many bytes were produced.
+ // Note: this is not a Sink method.
+ char* CurrentDestination() const { return dest_; }
+ private:
+ char* dest_;
+};
+
+} // namespace snappy
+
+#endif // THIRD_PARTY_SNAPPY_SNAPPY_SINKSOURCE_H_
diff --git a/other-licenses/snappy/src/snappy-stubs-internal.cc b/other-licenses/snappy/src/snappy-stubs-internal.cc
new file mode 100644
index 0000000000..0bc8c2d344
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-stubs-internal.cc
@@ -0,0 +1,42 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <algorithm>
+#include <string>
+
+#include "snappy-stubs-internal.h"
+
+namespace snappy {
+
+void Varint::Append32(std::string* s, uint32_t value) {
+ char buf[Varint::kMax32];
+ const char* p = Varint::Encode32(buf, value);
+ s->append(buf, p - buf);
+}
+
+} // namespace snappy
diff --git a/other-licenses/snappy/src/snappy-stubs-internal.h b/other-licenses/snappy/src/snappy-stubs-internal.h
new file mode 100644
index 0000000000..c2a838f38f
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-stubs-internal.h
@@ -0,0 +1,492 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various stubs for the open-source version of Snappy.
+
+#ifndef THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_
+#define THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <stdint.h>
+
+#include <cassert>
+#include <cstdlib>
+#include <cstring>
+#include <limits>
+#include <string>
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#if defined(_MSC_VER)
+#include <intrin.h>
+#endif // defined(_MSC_VER)
+
+#ifndef __has_feature
+#define __has_feature(x) 0
+#endif
+
+#if __has_feature(memory_sanitizer)
+#include <sanitizer/msan_interface.h>
+#define SNAPPY_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) \
+ __msan_unpoison((address), (size))
+#else
+#define SNAPPY_ANNOTATE_MEMORY_IS_INITIALIZED(address, size) /* empty */
+#endif // __has_feature(memory_sanitizer)
+
+#include "snappy-stubs-public.h"
+
+// Used to enable 64-bit optimized versions of some routines.
+#if defined(__PPC64__) || defined(__powerpc64__)
+#define ARCH_PPC 1
+#elif defined(__aarch64__) || defined(_M_ARM64)
+#define ARCH_ARM 1
+#endif
+
+// Needed by OS X, among others.
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON
+#endif
+
+// The size of an array, if known at compile-time.
+// Will give unexpected results if used on a pointer.
+// We undefine it first, since some compilers already have a definition.
+#ifdef ARRAYSIZE
+#undef ARRAYSIZE
+#endif
+#define ARRAYSIZE(a) int{sizeof(a) / sizeof(*(a))}
+
+// Static prediction hints.
+#ifdef HAVE_BUILTIN_EXPECT
+#define SNAPPY_PREDICT_FALSE(x) (__builtin_expect(x, 0))
+#define SNAPPY_PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
+#else
+#define SNAPPY_PREDICT_FALSE(x) x
+#define SNAPPY_PREDICT_TRUE(x) x
+#endif
+
+// Inlining hints.
+#ifdef HAVE_ATTRIBUTE_ALWAYS_INLINE
+#define SNAPPY_ATTRIBUTE_ALWAYS_INLINE __attribute__((always_inline))
+#else
+#define SNAPPY_ATTRIBUTE_ALWAYS_INLINE
+#endif
+
+// Stubbed version of ABSL_FLAG.
+//
+// In the open source version, flags can only be changed at compile time.
+#define SNAPPY_FLAG(flag_type, flag_name, default_value, help) \
+ flag_type FLAGS_ ## flag_name = default_value
+
+namespace snappy {
+
+// Stubbed version of absl::GetFlag().
+template <typename T>
+inline T GetFlag(T flag) { return flag; }
+
+static const uint32_t kuint32max = std::numeric_limits<uint32_t>::max();
+static const int64_t kint64max = std::numeric_limits<int64_t>::max();
+
+// Potentially unaligned loads and stores.
+
+inline uint16_t UNALIGNED_LOAD16(const void *p) {
+ // Compiles to a single movzx/ldrh on clang/gcc/msvc.
+ uint16_t v;
+ std::memcpy(&v, p, sizeof(v));
+ return v;
+}
+
+inline uint32_t UNALIGNED_LOAD32(const void *p) {
+ // Compiles to a single mov/ldr on clang/gcc/msvc.
+ uint32_t v;
+ std::memcpy(&v, p, sizeof(v));
+ return v;
+}
+
+inline uint64_t UNALIGNED_LOAD64(const void *p) {
+ // Compiles to a single mov/ldr on clang/gcc/msvc.
+ uint64_t v;
+ std::memcpy(&v, p, sizeof(v));
+ return v;
+}
+
+inline void UNALIGNED_STORE16(void *p, uint16_t v) {
+ // Compiles to a single mov/strh on clang/gcc/msvc.
+ std::memcpy(p, &v, sizeof(v));
+}
+
+inline void UNALIGNED_STORE32(void *p, uint32_t v) {
+ // Compiles to a single mov/str on clang/gcc/msvc.
+ std::memcpy(p, &v, sizeof(v));
+}
+
+inline void UNALIGNED_STORE64(void *p, uint64_t v) {
+ // Compiles to a single mov/str on clang/gcc/msvc.
+ std::memcpy(p, &v, sizeof(v));
+}
+
+// Convert to little-endian storage, opposite of network format.
+// Convert x from host to little endian: x = LittleEndian.FromHost(x);
+// convert x from little endian to host: x = LittleEndian.ToHost(x);
+//
+// Store values into unaligned memory converting to little endian order:
+// LittleEndian.Store16(p, x);
+//
+// Load unaligned values stored in little endian converting to host order:
+// x = LittleEndian.Load16(p);
+class LittleEndian {
+ public:
+ // Functions to do unaligned loads and stores in little-endian order.
+ static inline uint16_t Load16(const void *ptr) {
+ const uint8_t* const buffer = reinterpret_cast<const uint8_t*>(ptr);
+
+ // Compiles to a single mov/str on recent clang and gcc.
+ return (static_cast<uint16_t>(buffer[0])) |
+ (static_cast<uint16_t>(buffer[1]) << 8);
+ }
+
+ static inline uint32_t Load32(const void *ptr) {
+ const uint8_t* const buffer = reinterpret_cast<const uint8_t*>(ptr);
+
+ // Compiles to a single mov/str on recent clang and gcc.
+ return (static_cast<uint32_t>(buffer[0])) |
+ (static_cast<uint32_t>(buffer[1]) << 8) |
+ (static_cast<uint32_t>(buffer[2]) << 16) |
+ (static_cast<uint32_t>(buffer[3]) << 24);
+ }
+
+ static inline uint64_t Load64(const void *ptr) {
+ const uint8_t* const buffer = reinterpret_cast<const uint8_t*>(ptr);
+
+ // Compiles to a single mov/str on recent clang and gcc.
+ return (static_cast<uint64_t>(buffer[0])) |
+ (static_cast<uint64_t>(buffer[1]) << 8) |
+ (static_cast<uint64_t>(buffer[2]) << 16) |
+ (static_cast<uint64_t>(buffer[3]) << 24) |
+ (static_cast<uint64_t>(buffer[4]) << 32) |
+ (static_cast<uint64_t>(buffer[5]) << 40) |
+ (static_cast<uint64_t>(buffer[6]) << 48) |
+ (static_cast<uint64_t>(buffer[7]) << 56);
+ }
+
+ static inline void Store16(void *dst, uint16_t value) {
+ uint8_t* const buffer = reinterpret_cast<uint8_t*>(dst);
+
+ // Compiles to a single mov/str on recent clang and gcc.
+ buffer[0] = static_cast<uint8_t>(value);
+ buffer[1] = static_cast<uint8_t>(value >> 8);
+ }
+
+ static void Store32(void *dst, uint32_t value) {
+ uint8_t* const buffer = reinterpret_cast<uint8_t*>(dst);
+
+ // Compiles to a single mov/str on recent clang and gcc.
+ buffer[0] = static_cast<uint8_t>(value);
+ buffer[1] = static_cast<uint8_t>(value >> 8);
+ buffer[2] = static_cast<uint8_t>(value >> 16);
+ buffer[3] = static_cast<uint8_t>(value >> 24);
+ }
+
+ static void Store64(void* dst, uint64_t value) {
+ uint8_t* const buffer = reinterpret_cast<uint8_t*>(dst);
+
+ // Compiles to a single mov/str on recent clang and gcc.
+ buffer[0] = static_cast<uint8_t>(value);
+ buffer[1] = static_cast<uint8_t>(value >> 8);
+ buffer[2] = static_cast<uint8_t>(value >> 16);
+ buffer[3] = static_cast<uint8_t>(value >> 24);
+ buffer[4] = static_cast<uint8_t>(value >> 32);
+ buffer[5] = static_cast<uint8_t>(value >> 40);
+ buffer[6] = static_cast<uint8_t>(value >> 48);
+ buffer[7] = static_cast<uint8_t>(value >> 56);
+ }
+
+ static inline constexpr bool IsLittleEndian() {
+#if defined(SNAPPY_IS_BIG_ENDIAN)
+ return false;
+#else
+ return true;
+#endif // defined(SNAPPY_IS_BIG_ENDIAN)
+ }
+};
+
+// Some bit-manipulation functions.
+class Bits {
+ public:
+ // Return floor(log2(n)) for positive integer n.
+ static int Log2FloorNonZero(uint32_t n);
+
+ // Return floor(log2(n)) for positive integer n. Returns -1 iff n == 0.
+ static int Log2Floor(uint32_t n);
+
+ // Return the first set least / most significant bit, 0-indexed. Returns an
+ // undefined value if n == 0. FindLSBSetNonZero() is similar to ffs() except
+ // that it's 0-indexed.
+ static int FindLSBSetNonZero(uint32_t n);
+
+ static int FindLSBSetNonZero64(uint64_t n);
+
+ private:
+ // No copying
+ Bits(const Bits&);
+ void operator=(const Bits&);
+};
+
+#if defined(HAVE_BUILTIN_CTZ)
+
+inline int Bits::Log2FloorNonZero(uint32_t n) {
+ assert(n != 0);
+ // (31 ^ x) is equivalent to (31 - x) for x in [0, 31]. An easy proof
+ // represents subtraction in base 2 and observes that there's no carry.
+ //
+ // GCC and Clang represent __builtin_clz on x86 as 31 ^ _bit_scan_reverse(x).
+ // Using "31 ^" here instead of "31 -" allows the optimizer to strip the
+ // function body down to _bit_scan_reverse(x).
+ return 31 ^ __builtin_clz(n);
+}
+
+inline int Bits::Log2Floor(uint32_t n) {
+ return (n == 0) ? -1 : Bits::Log2FloorNonZero(n);
+}
+
+inline int Bits::FindLSBSetNonZero(uint32_t n) {
+ assert(n != 0);
+ return __builtin_ctz(n);
+}
+
+#elif defined(_MSC_VER)
+
+inline int Bits::Log2FloorNonZero(uint32_t n) {
+ assert(n != 0);
+ // NOLINTNEXTLINE(runtime/int): The MSVC intrinsic demands unsigned long.
+ unsigned long where;
+ _BitScanReverse(&where, n);
+ return static_cast<int>(where);
+}
+
+inline int Bits::Log2Floor(uint32_t n) {
+ // NOLINTNEXTLINE(runtime/int): The MSVC intrinsic demands unsigned long.
+ unsigned long where;
+ if (_BitScanReverse(&where, n))
+ return static_cast<int>(where);
+ return -1;
+}
+
+inline int Bits::FindLSBSetNonZero(uint32_t n) {
+ assert(n != 0);
+ // NOLINTNEXTLINE(runtime/int): The MSVC intrinsic demands unsigned long.
+ unsigned long where;
+ if (_BitScanForward(&where, n))
+ return static_cast<int>(where);
+ return 32;
+}
+
+#else // Portable versions.
+
+inline int Bits::Log2FloorNonZero(uint32_t n) {
+ assert(n != 0);
+
+ int log = 0;
+ uint32_t value = n;
+ for (int i = 4; i >= 0; --i) {
+ int shift = (1 << i);
+ uint32_t x = value >> shift;
+ if (x != 0) {
+ value = x;
+ log += shift;
+ }
+ }
+ assert(value == 1);
+ return log;
+}
+
+inline int Bits::Log2Floor(uint32_t n) {
+ return (n == 0) ? -1 : Bits::Log2FloorNonZero(n);
+}
+
+inline int Bits::FindLSBSetNonZero(uint32_t n) {
+ assert(n != 0);
+
+ int rc = 31;
+ for (int i = 4, shift = 1 << 4; i >= 0; --i) {
+ const uint32_t x = n << shift;
+ if (x != 0) {
+ n = x;
+ rc -= shift;
+ }
+ shift >>= 1;
+ }
+ return rc;
+}
+
+#endif // End portable versions.
+
+#if defined(HAVE_BUILTIN_CTZ)
+
+inline int Bits::FindLSBSetNonZero64(uint64_t n) {
+ assert(n != 0);
+ return __builtin_ctzll(n);
+}
+
+#elif defined(_MSC_VER) && (defined(_M_X64) || defined(_M_ARM64))
+// _BitScanForward64() is only available on x64 and ARM64.
+
+inline int Bits::FindLSBSetNonZero64(uint64_t n) {
+ assert(n != 0);
+ // NOLINTNEXTLINE(runtime/int): The MSVC intrinsic demands unsigned long.
+ unsigned long where;
+ if (_BitScanForward64(&where, n))
+ return static_cast<int>(where);
+ return 64;
+}
+
+#else // Portable version.
+
+// FindLSBSetNonZero64() is defined in terms of FindLSBSetNonZero().
+inline int Bits::FindLSBSetNonZero64(uint64_t n) {
+ assert(n != 0);
+
+ const uint32_t bottombits = static_cast<uint32_t>(n);
+ if (bottombits == 0) {
+ // Bottom bits are zero, so scan the top bits.
+ return 32 + FindLSBSetNonZero(static_cast<uint32_t>(n >> 32));
+ } else {
+ return FindLSBSetNonZero(bottombits);
+ }
+}
+
+#endif // End portable version.
+
+// Variable-length integer encoding.
+class Varint {
+ public:
+ // Maximum lengths of varint encoding of uint32_t.
+ static const int kMax32 = 5;
+
+ // Attempts to parse a varint32 from a prefix of the bytes in [ptr,limit-1].
+ // Never reads a character at or beyond limit. If a valid/terminated varint32
+ // was found in the range, stores it in *OUTPUT and returns a pointer just
+ // past the last byte of the varint32. Else returns NULL. On success,
+ // "result <= limit".
+ static const char* Parse32WithLimit(const char* ptr, const char* limit,
+ uint32_t* OUTPUT);
+
+ // REQUIRES "ptr" points to a buffer of length sufficient to hold "v".
+ // EFFECTS Encodes "v" into "ptr" and returns a pointer to the
+ // byte just past the last encoded byte.
+ static char* Encode32(char* ptr, uint32_t v);
+
+ // EFFECTS Appends the varint representation of "value" to "*s".
+ static void Append32(std::string* s, uint32_t value);
+};
+
+inline const char* Varint::Parse32WithLimit(const char* p,
+ const char* l,
+ uint32_t* OUTPUT) {
+ const unsigned char* ptr = reinterpret_cast<const unsigned char*>(p);
+ const unsigned char* limit = reinterpret_cast<const unsigned char*>(l);
+ uint32_t b, result;
+ if (ptr >= limit) return NULL;
+ b = *(ptr++); result = b & 127; if (b < 128) goto done;
+ if (ptr >= limit) return NULL;
+ b = *(ptr++); result |= (b & 127) << 7; if (b < 128) goto done;
+ if (ptr >= limit) return NULL;
+ b = *(ptr++); result |= (b & 127) << 14; if (b < 128) goto done;
+ if (ptr >= limit) return NULL;
+ b = *(ptr++); result |= (b & 127) << 21; if (b < 128) goto done;
+ if (ptr >= limit) return NULL;
+ b = *(ptr++); result |= (b & 127) << 28; if (b < 16) goto done;
+ return NULL; // Value is too long to be a varint32
+ done:
+ *OUTPUT = result;
+ return reinterpret_cast<const char*>(ptr);
+}
+
+inline char* Varint::Encode32(char* sptr, uint32_t v) {
+ // Operate on characters as unsigneds
+ uint8_t* ptr = reinterpret_cast<uint8_t*>(sptr);
+ static const uint8_t B = 128;
+ if (v < (1 << 7)) {
+ *(ptr++) = static_cast<uint8_t>(v);
+ } else if (v < (1 << 14)) {
+ *(ptr++) = static_cast<uint8_t>(v | B);
+ *(ptr++) = static_cast<uint8_t>(v >> 7);
+ } else if (v < (1 << 21)) {
+ *(ptr++) = static_cast<uint8_t>(v | B);
+ *(ptr++) = static_cast<uint8_t>((v >> 7) | B);
+ *(ptr++) = static_cast<uint8_t>(v >> 14);
+ } else if (v < (1 << 28)) {
+ *(ptr++) = static_cast<uint8_t>(v | B);
+ *(ptr++) = static_cast<uint8_t>((v >> 7) | B);
+ *(ptr++) = static_cast<uint8_t>((v >> 14) | B);
+ *(ptr++) = static_cast<uint8_t>(v >> 21);
+ } else {
+ *(ptr++) = static_cast<uint8_t>(v | B);
+ *(ptr++) = static_cast<uint8_t>((v>>7) | B);
+ *(ptr++) = static_cast<uint8_t>((v>>14) | B);
+ *(ptr++) = static_cast<uint8_t>((v>>21) | B);
+ *(ptr++) = static_cast<uint8_t>(v >> 28);
+ }
+ return reinterpret_cast<char*>(ptr);
+}
+
+// If you know the internal layout of the std::string in use, you can
+// replace this function with one that resizes the string without
+// filling the new space with zeros (if applicable) --
+// it will be non-portable but faster.
+inline void STLStringResizeUninitialized(std::string* s, size_t new_size) {
+ s->resize(new_size);
+}
+
+// Return a mutable char* pointing to a string's internal buffer,
+// which may not be null-terminated. Writing through this pointer will
+// modify the string.
+//
+// string_as_array(&str)[i] is valid for 0 <= i < str.size() until the
+// next call to a string method that invalidates iterators.
+//
+// As of 2006-04, there is no standard-blessed way of getting a
+// mutable reference to a string's internal buffer. However, issue 530
+// (http://www.open-std.org/JTC1/SC22/WG21/docs/lwg-defects.html#530)
+// proposes this as the method. It will officially be part of the standard
+// for C++0x. This should already work on all current implementations.
+inline char* string_as_array(std::string* str) {
+ return str->empty() ? NULL : &*str->begin();
+}
+
+} // namespace snappy
+
+#endif // THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_
diff --git a/other-licenses/snappy/src/snappy-stubs-public.h.in b/other-licenses/snappy/src/snappy-stubs-public.h.in
new file mode 100644
index 0000000000..02947fabd5
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-stubs-public.h.in
@@ -0,0 +1,63 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various type stubs for the open-source version of Snappy.
+//
+// This file cannot include config.h, as it is included from snappy.h,
+// which is a public header. Instead, snappy-stubs-public.h is generated by
+// from snappy-stubs-public.h.in at configure time.
+
+#ifndef THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+#define THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+
+#include <cstddef>
+
+#if ${HAVE_SYS_UIO_H_01} // HAVE_SYS_UIO_H
+#include <sys/uio.h>
+#endif // HAVE_SYS_UIO_H
+
+#define SNAPPY_MAJOR ${PROJECT_VERSION_MAJOR}
+#define SNAPPY_MINOR ${PROJECT_VERSION_MINOR}
+#define SNAPPY_PATCHLEVEL ${PROJECT_VERSION_PATCH}
+#define SNAPPY_VERSION \
+ ((SNAPPY_MAJOR << 16) | (SNAPPY_MINOR << 8) | SNAPPY_PATCHLEVEL)
+
+namespace snappy {
+
+#if !${HAVE_SYS_UIO_H_01} // !HAVE_SYS_UIO_H
+// Windows does not have an iovec type, yet the concept is universally useful.
+// It is simple to define it ourselves, so we put it inside our own namespace.
+struct iovec {
+ void* iov_base;
+ size_t iov_len;
+};
+#endif // !HAVE_SYS_UIO_H
+
+} // namespace snappy
+
+#endif // THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
diff --git a/other-licenses/snappy/src/snappy-test.cc b/other-licenses/snappy/src/snappy-test.cc
new file mode 100644
index 0000000000..7eb490ac17
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-test.cc
@@ -0,0 +1,503 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various stubs for the unit tests for the open-source version of Snappy.
+
+#include "snappy-test.h"
+
+#include <algorithm>
+#include <cstdarg>
+#include <cstdio>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+
+namespace file {
+
+OptionsStub::OptionsStub() = default;
+OptionsStub::~OptionsStub() = default;
+
+const OptionsStub &Defaults() {
+ static OptionsStub defaults;
+ return defaults;
+}
+
+StatusStub::StatusStub() = default;
+StatusStub::StatusStub(const StatusStub &) = default;
+StatusStub &StatusStub::operator=(const StatusStub &) = default;
+StatusStub::~StatusStub() = default;
+
+bool StatusStub::ok() { return true; }
+
+StatusStub GetContents(const std::string &filename, std::string *output,
+ const OptionsStub & /* options */) {
+ std::FILE *fp = std::fopen(filename.c_str(), "rb");
+ if (fp == nullptr) {
+ std::perror(filename.c_str());
+ std::exit(1);
+ }
+
+ output->clear();
+ while (!std::feof(fp)) {
+ char buffer[4096];
+ size_t bytes_read = std::fread(buffer, 1, sizeof(buffer), fp);
+ if (bytes_read == 0 && std::ferror(fp)) {
+ std::perror("fread");
+ std::exit(1);
+ }
+ output->append(buffer, bytes_read);
+ }
+
+ std::fclose(fp);
+ return StatusStub();
+}
+
+StatusStub SetContents(const std::string &file_name, const std::string &content,
+ const OptionsStub & /* options */) {
+ std::FILE *fp = std::fopen(file_name.c_str(), "wb");
+ if (fp == nullptr) {
+ std::perror(file_name.c_str());
+ std::exit(1);
+ }
+
+ size_t bytes_written = std::fwrite(content.data(), 1, content.size(), fp);
+ if (bytes_written != content.size()) {
+ std::perror("fwrite");
+ std::exit(1);
+ }
+
+ std::fclose(fp);
+ return StatusStub();
+}
+
+} // namespace file
+
+namespace snappy {
+
+std::string ReadTestDataFile(const std::string& base, size_t size_limit) {
+ std::string contents;
+ const char* srcdir = getenv("srcdir"); // This is set by Automake.
+ std::string prefix;
+ if (srcdir) {
+ prefix = std::string(srcdir) + "/";
+ }
+ file::GetContents(prefix + "testdata/" + base, &contents, file::Defaults()
+ ).ok();
+ if (size_limit > 0) {
+ contents = contents.substr(0, size_limit);
+ }
+ return contents;
+}
+
+std::string StrFormat(const char* format, ...) {
+ char buffer[4096];
+ std::va_list ap;
+ va_start(ap, format);
+ std::vsnprintf(buffer, sizeof(buffer), format, ap);
+ va_end(ap);
+ return buffer;
+}
+
+LogMessage::~LogMessage() { std::cerr << std::endl; }
+
+LogMessage &LogMessage::operator<<(const std::string &message) {
+ std::cerr << message;
+ return *this;
+}
+
+LogMessage &LogMessage::operator<<(int number) {
+ std::cerr << number;
+ return *this;
+}
+
+#ifdef _MSC_VER
+// ~LogMessageCrash calls std::abort() and therefore never exits. This is by
+// design, so temporarily disable warning C4722.
+#pragma warning(push)
+#pragma warning(disable : 4722)
+#endif
+
+LogMessageCrash::~LogMessageCrash() {
+ std::cerr << std::endl;
+ std::abort();
+}
+
+#ifdef _MSC_VER
+#pragma warning(pop)
+#endif
+
+#ifdef HAVE_LIBZ
+
+ZLib::ZLib()
+ : comp_init_(false),
+ uncomp_init_(false) {
+ Reinit();
+}
+
+ZLib::~ZLib() {
+ if (comp_init_) { deflateEnd(&comp_stream_); }
+ if (uncomp_init_) { inflateEnd(&uncomp_stream_); }
+}
+
+void ZLib::Reinit() {
+ compression_level_ = Z_DEFAULT_COMPRESSION;
+ window_bits_ = MAX_WBITS;
+ mem_level_ = 8; // DEF_MEM_LEVEL
+ if (comp_init_) {
+ deflateEnd(&comp_stream_);
+ comp_init_ = false;
+ }
+ if (uncomp_init_) {
+ inflateEnd(&uncomp_stream_);
+ uncomp_init_ = false;
+ }
+ first_chunk_ = true;
+}
+
+void ZLib::Reset() {
+ first_chunk_ = true;
+}
+
+// --------- COMPRESS MODE
+
+// Initialization method to be called if we hit an error while
+// compressing. On hitting an error, call this method before returning
+// the error.
+void ZLib::CompressErrorInit() {
+ deflateEnd(&comp_stream_);
+ comp_init_ = false;
+ Reset();
+}
+
+int ZLib::DeflateInit() {
+ return deflateInit2(&comp_stream_,
+ compression_level_,
+ Z_DEFLATED,
+ window_bits_,
+ mem_level_,
+ Z_DEFAULT_STRATEGY);
+}
+
+int ZLib::CompressInit(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen) {
+ int err;
+
+ comp_stream_.next_in = (Bytef*)source;
+ comp_stream_.avail_in = (uInt)*sourceLen;
+ if ((uLong)comp_stream_.avail_in != *sourceLen) return Z_BUF_ERROR;
+ comp_stream_.next_out = dest;
+ comp_stream_.avail_out = (uInt)*destLen;
+ if ((uLong)comp_stream_.avail_out != *destLen) return Z_BUF_ERROR;
+
+ if ( !first_chunk_ ) // only need to set up stream the first time through
+ return Z_OK;
+
+ if (comp_init_) { // we've already initted it
+ err = deflateReset(&comp_stream_);
+ if (err != Z_OK) {
+ LOG(WARNING) << "ERROR: Can't reset compress object; creating a new one";
+ deflateEnd(&comp_stream_);
+ comp_init_ = false;
+ }
+ }
+ if (!comp_init_) { // first use
+ comp_stream_.zalloc = (alloc_func)0;
+ comp_stream_.zfree = (free_func)0;
+ comp_stream_.opaque = (voidpf)0;
+ err = DeflateInit();
+ if (err != Z_OK) return err;
+ comp_init_ = true;
+ }
+ return Z_OK;
+}
+
+// In a perfect world we'd always have the full buffer to compress
+// when the time came, and we could just call Compress(). Alas, we
+// want to do chunked compression on our webserver. In this
+// application, we compress the header, send it off, then compress the
+// results, send them off, then compress the footer. Thus we need to
+// use the chunked compression features of zlib.
+int ZLib::CompressAtMostOrAll(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen,
+ int flush_mode) { // Z_FULL_FLUSH or Z_FINISH
+ int err;
+
+ if ( (err=CompressInit(dest, destLen, source, sourceLen)) != Z_OK )
+ return err;
+
+ // This is used to figure out how many bytes we wrote *this chunk*
+ int compressed_size = comp_stream_.total_out;
+
+ // Some setup happens only for the first chunk we compress in a run
+ if ( first_chunk_ ) {
+ first_chunk_ = false;
+ }
+
+ // flush_mode is Z_FINISH for all mode, Z_SYNC_FLUSH for incremental
+ // compression.
+ err = deflate(&comp_stream_, flush_mode);
+
+ *sourceLen = comp_stream_.avail_in;
+
+ if ((err == Z_STREAM_END || err == Z_OK)
+ && comp_stream_.avail_in == 0
+ && comp_stream_.avail_out != 0 ) {
+ // we processed everything ok and the output buffer was large enough.
+ ;
+ } else if (err == Z_STREAM_END && comp_stream_.avail_in > 0) {
+ return Z_BUF_ERROR; // should never happen
+ } else if (err != Z_OK && err != Z_STREAM_END && err != Z_BUF_ERROR) {
+ // an error happened
+ CompressErrorInit();
+ return err;
+ } else if (comp_stream_.avail_out == 0) { // not enough space
+ err = Z_BUF_ERROR;
+ }
+
+ assert(err == Z_OK || err == Z_STREAM_END || err == Z_BUF_ERROR);
+ if (err == Z_STREAM_END)
+ err = Z_OK;
+
+ // update the crc and other metadata
+ compressed_size = comp_stream_.total_out - compressed_size; // delta
+ *destLen = compressed_size;
+
+ return err;
+}
+
+int ZLib::CompressChunkOrAll(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen,
+ int flush_mode) { // Z_FULL_FLUSH or Z_FINISH
+ const int ret =
+ CompressAtMostOrAll(dest, destLen, source, &sourceLen, flush_mode);
+ if (ret == Z_BUF_ERROR)
+ CompressErrorInit();
+ return ret;
+}
+
+// This routine only initializes the compression stream once. Thereafter, it
+// just does a deflateReset on the stream, which should be faster.
+int ZLib::Compress(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen) {
+ int err;
+ if ( (err=CompressChunkOrAll(dest, destLen, source, sourceLen,
+ Z_FINISH)) != Z_OK )
+ return err;
+ Reset(); // reset for next call to Compress
+
+ return Z_OK;
+}
+
+
+// --------- UNCOMPRESS MODE
+
+int ZLib::InflateInit() {
+ return inflateInit2(&uncomp_stream_, MAX_WBITS);
+}
+
+// Initialization method to be called if we hit an error while
+// uncompressing. On hitting an error, call this method before
+// returning the error.
+void ZLib::UncompressErrorInit() {
+ inflateEnd(&uncomp_stream_);
+ uncomp_init_ = false;
+ Reset();
+}
+
+int ZLib::UncompressInit(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen) {
+ int err;
+
+ uncomp_stream_.next_in = (Bytef*)source;
+ uncomp_stream_.avail_in = (uInt)*sourceLen;
+ // Check for source > 64K on 16-bit machine:
+ if ((uLong)uncomp_stream_.avail_in != *sourceLen) return Z_BUF_ERROR;
+
+ uncomp_stream_.next_out = dest;
+ uncomp_stream_.avail_out = (uInt)*destLen;
+ if ((uLong)uncomp_stream_.avail_out != *destLen) return Z_BUF_ERROR;
+
+ if ( !first_chunk_ ) // only need to set up stream the first time through
+ return Z_OK;
+
+ if (uncomp_init_) { // we've already initted it
+ err = inflateReset(&uncomp_stream_);
+ if (err != Z_OK) {
+ LOG(WARNING)
+ << "ERROR: Can't reset uncompress object; creating a new one";
+ UncompressErrorInit();
+ }
+ }
+ if (!uncomp_init_) {
+ uncomp_stream_.zalloc = (alloc_func)0;
+ uncomp_stream_.zfree = (free_func)0;
+ uncomp_stream_.opaque = (voidpf)0;
+ err = InflateInit();
+ if (err != Z_OK) return err;
+ uncomp_init_ = true;
+ }
+ return Z_OK;
+}
+
+// If you compressed your data a chunk at a time, with CompressChunk,
+// you can uncompress it a chunk at a time with UncompressChunk.
+// Only difference bewteen chunked and unchunked uncompression
+// is the flush mode we use: Z_SYNC_FLUSH (chunked) or Z_FINISH (unchunked).
+int ZLib::UncompressAtMostOrAll(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen,
+ int flush_mode) { // Z_SYNC_FLUSH or Z_FINISH
+ int err = Z_OK;
+
+ if ( (err=UncompressInit(dest, destLen, source, sourceLen)) != Z_OK ) {
+ LOG(WARNING) << "UncompressInit: Error: " << err << " SourceLen: "
+ << *sourceLen;
+ return err;
+ }
+
+ // This is used to figure out how many output bytes we wrote *this chunk*:
+ const uLong old_total_out = uncomp_stream_.total_out;
+
+ // This is used to figure out how many input bytes we read *this chunk*:
+ const uLong old_total_in = uncomp_stream_.total_in;
+
+ // Some setup happens only for the first chunk we compress in a run
+ if ( first_chunk_ ) {
+ first_chunk_ = false; // so we don't do this again
+
+ // For the first chunk *only* (to avoid infinite troubles), we let
+ // there be no actual data to uncompress. This sometimes triggers
+ // when the input is only the gzip header, say.
+ if ( *sourceLen == 0 ) {
+ *destLen = 0;
+ return Z_OK;
+ }
+ }
+
+ // We'll uncompress as much as we can. If we end OK great, otherwise
+ // if we get an error that seems to be the gzip footer, we store the
+ // gzip footer and return OK, otherwise we return the error.
+
+ // flush_mode is Z_SYNC_FLUSH for chunked mode, Z_FINISH for all mode.
+ err = inflate(&uncomp_stream_, flush_mode);
+
+ // Figure out how many bytes of the input zlib slurped up:
+ const uLong bytes_read = uncomp_stream_.total_in - old_total_in;
+ CHECK_LE(source + bytes_read, source + *sourceLen);
+ *sourceLen = uncomp_stream_.avail_in;
+
+ if ((err == Z_STREAM_END || err == Z_OK) // everything went ok
+ && uncomp_stream_.avail_in == 0) { // and we read it all
+ ;
+ } else if (err == Z_STREAM_END && uncomp_stream_.avail_in > 0) {
+ LOG(WARNING)
+ << "UncompressChunkOrAll: Received some extra data, bytes total: "
+ << uncomp_stream_.avail_in << " bytes: "
+ << std::string(reinterpret_cast<const char *>(uncomp_stream_.next_in),
+ std::min(int(uncomp_stream_.avail_in), 20));
+ UncompressErrorInit();
+ return Z_DATA_ERROR; // what's the extra data for?
+ } else if (err != Z_OK && err != Z_STREAM_END && err != Z_BUF_ERROR) {
+ // an error happened
+ LOG(WARNING) << "UncompressChunkOrAll: Error: " << err
+ << " avail_out: " << uncomp_stream_.avail_out;
+ UncompressErrorInit();
+ return err;
+ } else if (uncomp_stream_.avail_out == 0) {
+ err = Z_BUF_ERROR;
+ }
+
+ assert(err == Z_OK || err == Z_BUF_ERROR || err == Z_STREAM_END);
+ if (err == Z_STREAM_END)
+ err = Z_OK;
+
+ *destLen = uncomp_stream_.total_out - old_total_out; // size for this call
+
+ return err;
+}
+
+int ZLib::UncompressChunkOrAll(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen,
+ int flush_mode) { // Z_SYNC_FLUSH or Z_FINISH
+ const int ret =
+ UncompressAtMostOrAll(dest, destLen, source, &sourceLen, flush_mode);
+ if (ret == Z_BUF_ERROR)
+ UncompressErrorInit();
+ return ret;
+}
+
+int ZLib::UncompressAtMost(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen) {
+ return UncompressAtMostOrAll(dest, destLen, source, sourceLen, Z_SYNC_FLUSH);
+}
+
+// We make sure we've uncompressed everything, that is, the current
+// uncompress stream is at a compressed-buffer-EOF boundary. In gzip
+// mode, we also check the gzip footer to make sure we pass the gzip
+// consistency checks. We RETURN true iff both types of checks pass.
+bool ZLib::UncompressChunkDone() {
+ assert(!first_chunk_ && uncomp_init_);
+ // Make sure we're at the end-of-compressed-data point. This means
+ // if we call inflate with Z_FINISH we won't consume any input or
+ // write any output
+ Bytef dummyin, dummyout;
+ uLongf dummylen = 0;
+ if ( UncompressChunkOrAll(&dummyout, &dummylen, &dummyin, 0, Z_FINISH)
+ != Z_OK ) {
+ return false;
+ }
+
+ // Make sure that when we exit, we can start a new round of chunks later
+ Reset();
+
+ return true;
+}
+
+// Uncompresses the source buffer into the destination buffer.
+// The destination buffer must be long enough to hold the entire
+// decompressed contents.
+//
+// We only initialize the uncomp_stream once. Thereafter, we use
+// inflateReset, which should be faster.
+//
+// Returns Z_OK on success, otherwise, it returns a zlib error code.
+int ZLib::Uncompress(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen) {
+ int err;
+ if ( (err=UncompressChunkOrAll(dest, destLen, source, sourceLen,
+ Z_FINISH)) != Z_OK ) {
+ Reset(); // let us try to compress again
+ return err;
+ }
+ if ( !UncompressChunkDone() ) // calls Reset()
+ return Z_DATA_ERROR;
+ return Z_OK; // stream_end is ok
+}
+
+#endif // HAVE_LIBZ
+
+} // namespace snappy
diff --git a/other-licenses/snappy/src/snappy-test.h b/other-licenses/snappy/src/snappy-test.h
new file mode 100644
index 0000000000..f80d343377
--- /dev/null
+++ b/other-licenses/snappy/src/snappy-test.h
@@ -0,0 +1,342 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various stubs for the unit tests for the open-source version of Snappy.
+
+#ifndef THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_TEST_H_
+#define THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_TEST_H_
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include "snappy-stubs-internal.h"
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
+
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#ifdef HAVE_WINDOWS_H
+// Needed to be able to use std::max without workarounds in the source code.
+// https://support.microsoft.com/en-us/help/143208/prb-using-stl-in-windows-program-can-cause-min-max-conflicts
+#define NOMINMAX
+#include <windows.h>
+#endif
+
+#define InitGoogle(argv0, argc, argv, remove_flags) ((void)(0))
+
+#ifdef HAVE_LIBZ
+#include "zlib.h"
+#endif
+
+#ifdef HAVE_LIBLZO2
+#include "lzo/lzo1x.h"
+#endif
+
+#ifdef HAVE_LIBLZ4
+#include "lz4.h"
+#endif
+
+namespace file {
+
+// Stubs the class file::Options.
+//
+// This class should not be instantiated explicitly. It should only be used by
+// passing file::Defaults() to file::GetContents() / file::SetContents().
+class OptionsStub {
+ public:
+ OptionsStub();
+ OptionsStub(const OptionsStub &) = delete;
+ OptionsStub &operator=(const OptionsStub &) = delete;
+ ~OptionsStub();
+};
+
+const OptionsStub &Defaults();
+
+// Stubs the class absl::Status.
+//
+// This class should not be instantiated explicitly. It should only be used by
+// passing the result of file::GetContents() / file::SetContents() to
+// CHECK_OK().
+class StatusStub {
+ public:
+ StatusStub();
+ StatusStub(const StatusStub &);
+ StatusStub &operator=(const StatusStub &);
+ ~StatusStub();
+
+ bool ok();
+};
+
+StatusStub GetContents(const std::string &file_name, std::string *output,
+ const OptionsStub & /* options */);
+
+StatusStub SetContents(const std::string &file_name, const std::string &content,
+ const OptionsStub & /* options */);
+
+} // namespace file
+
+namespace snappy {
+
+#define FLAGS_test_random_seed 301
+
+std::string ReadTestDataFile(const std::string& base, size_t size_limit);
+
+// A std::sprintf() variant that returns a std::string.
+// Not safe for general use due to truncation issues.
+std::string StrFormat(const char* format, ...);
+
+// A wall-time clock. This stub is not super-accurate, nor resistant to the
+// system time changing.
+class CycleTimer {
+ public:
+ inline CycleTimer() : real_time_us_(0) {}
+ inline ~CycleTimer() = default;
+
+ inline void Start() {
+#ifdef WIN32
+ QueryPerformanceCounter(&start_);
+#else
+ ::gettimeofday(&start_, nullptr);
+#endif
+ }
+
+ inline void Stop() {
+#ifdef WIN32
+ LARGE_INTEGER stop;
+ LARGE_INTEGER frequency;
+ QueryPerformanceCounter(&stop);
+ QueryPerformanceFrequency(&frequency);
+
+ double elapsed = static_cast<double>(stop.QuadPart - start_.QuadPart) /
+ frequency.QuadPart;
+ real_time_us_ += elapsed * 1e6 + 0.5;
+#else
+ struct ::timeval stop;
+ ::gettimeofday(&stop, nullptr);
+
+ real_time_us_ += 1000000 * (stop.tv_sec - start_.tv_sec);
+ real_time_us_ += (stop.tv_usec - start_.tv_usec);
+#endif
+ }
+
+ inline double Get() { return real_time_us_ * 1e-6; }
+
+ private:
+ int64_t real_time_us_;
+#ifdef WIN32
+ LARGE_INTEGER start_;
+#else
+ struct ::timeval start_;
+#endif
+};
+
+// Logging.
+
+class LogMessage {
+ public:
+ inline LogMessage() = default;
+ ~LogMessage();
+
+ LogMessage &operator<<(const std::string &message);
+ LogMessage &operator<<(int number);
+};
+
+class LogMessageCrash : public LogMessage {
+ public:
+ inline LogMessageCrash() = default;
+ ~LogMessageCrash();
+};
+
+// This class is used to explicitly ignore values in the conditional
+// logging macros. This avoids compiler warnings like "value computed
+// is not used" and "statement has no effect".
+
+class LogMessageVoidify {
+ public:
+ inline LogMessageVoidify() = default;
+ inline ~LogMessageVoidify() = default;
+
+ // This has to be an operator with a precedence lower than << but
+ // higher than ?:
+ inline void operator&(const LogMessage &) {}
+};
+
+// Asserts, both versions activated in debug mode only,
+// and ones that are always active.
+
+#define CRASH_UNLESS(condition) \
+ SNAPPY_PREDICT_TRUE(condition) \
+ ? (void)0 \
+ : snappy::LogMessageVoidify() & snappy::LogMessageCrash()
+
+#define LOG(level) LogMessage()
+#define VLOG(level) \
+ true ? (void)0 : snappy::LogMessageVoidify() & snappy::LogMessage()
+
+#define CHECK(cond) CRASH_UNLESS(cond)
+#define CHECK_LE(a, b) CRASH_UNLESS((a) <= (b))
+#define CHECK_GE(a, b) CRASH_UNLESS((a) >= (b))
+#define CHECK_EQ(a, b) CRASH_UNLESS((a) == (b))
+#define CHECK_NE(a, b) CRASH_UNLESS((a) != (b))
+#define CHECK_LT(a, b) CRASH_UNLESS((a) < (b))
+#define CHECK_GT(a, b) CRASH_UNLESS((a) > (b))
+#define CHECK_OK(cond) (cond).ok()
+
+#ifdef HAVE_LIBZ
+
+// Object-oriented wrapper around zlib.
+class ZLib {
+ public:
+ ZLib();
+ ~ZLib();
+
+ // Wipe a ZLib object to a virgin state. This differs from Reset()
+ // in that it also breaks any state.
+ void Reinit();
+
+ // Call this to make a zlib buffer as good as new. Here's the only
+ // case where they differ:
+ // CompressChunk(a); CompressChunk(b); CompressChunkDone(); vs
+ // CompressChunk(a); Reset(); CompressChunk(b); CompressChunkDone();
+ // You'll want to use Reset(), then, when you interrupt a compress
+ // (or uncompress) in the middle of a chunk and want to start over.
+ void Reset();
+
+ // According to the zlib manual, when you Compress, the destination
+ // buffer must have size at least src + .1%*src + 12. This function
+ // helps you calculate that. Augment this to account for a potential
+ // gzip header and footer, plus a few bytes of slack.
+ static int MinCompressbufSize(int uncompress_size) {
+ return uncompress_size + uncompress_size/1000 + 40;
+ }
+
+ // Compresses the source buffer into the destination buffer.
+ // sourceLen is the byte length of the source buffer.
+ // Upon entry, destLen is the total size of the destination buffer,
+ // which must be of size at least MinCompressbufSize(sourceLen).
+ // Upon exit, destLen is the actual size of the compressed buffer.
+ //
+ // This function can be used to compress a whole file at once if the
+ // input file is mmap'ed.
+ //
+ // Returns Z_OK if success, Z_MEM_ERROR if there was not
+ // enough memory, Z_BUF_ERROR if there was not enough room in the
+ // output buffer. Note that if the output buffer is exactly the same
+ // size as the compressed result, we still return Z_BUF_ERROR.
+ // (check CL#1936076)
+ int Compress(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen);
+
+ // Uncompresses the source buffer into the destination buffer.
+ // The destination buffer must be long enough to hold the entire
+ // decompressed contents.
+ //
+ // Returns Z_OK on success, otherwise, it returns a zlib error code.
+ int Uncompress(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen);
+
+ // Uncompress data one chunk at a time -- ie you can call this
+ // more than once. To get this to work you need to call per-chunk
+ // and "done" routines.
+ //
+ // Returns Z_OK if success, Z_MEM_ERROR if there was not
+ // enough memory, Z_BUF_ERROR if there was not enough room in the
+ // output buffer.
+
+ int UncompressAtMost(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen);
+
+ // Checks gzip footer information, as needed. Mostly this just
+ // makes sure the checksums match. Whenever you call this, it
+ // will assume the last 8 bytes from the previous UncompressChunk
+ // call are the footer. Returns true iff everything looks ok.
+ bool UncompressChunkDone();
+
+ private:
+ int InflateInit(); // sets up the zlib inflate structure
+ int DeflateInit(); // sets up the zlib deflate structure
+
+ // These init the zlib data structures for compressing/uncompressing
+ int CompressInit(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen);
+ int UncompressInit(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen);
+ // Initialization method to be called if we hit an error while
+ // uncompressing. On hitting an error, call this method before
+ // returning the error.
+ void UncompressErrorInit();
+
+ // Helper function for Compress
+ int CompressChunkOrAll(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen,
+ int flush_mode);
+ int CompressAtMostOrAll(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen,
+ int flush_mode);
+
+ // Likewise for UncompressAndUncompressChunk
+ int UncompressChunkOrAll(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong sourceLen,
+ int flush_mode);
+
+ int UncompressAtMostOrAll(Bytef *dest, uLongf *destLen,
+ const Bytef *source, uLong *sourceLen,
+ int flush_mode);
+
+ // Initialization method to be called if we hit an error while
+ // compressing. On hitting an error, call this method before
+ // returning the error.
+ void CompressErrorInit();
+
+ int compression_level_; // compression level
+ int window_bits_; // log base 2 of the window size used in compression
+ int mem_level_; // specifies the amount of memory to be used by
+ // compressor (1-9)
+ z_stream comp_stream_; // Zlib stream data structure
+ bool comp_init_; // True if we have initialized comp_stream_
+ z_stream uncomp_stream_; // Zlib stream data structure
+ bool uncomp_init_; // True if we have initialized uncomp_stream_
+
+ // These are used only with chunked compression.
+ bool first_chunk_; // true if we need to emit headers with this chunk
+};
+
+#endif // HAVE_LIBZ
+
+} // namespace snappy
+
+#endif // THIRD_PARTY_SNAPPY_OPENSOURCE_SNAPPY_TEST_H_
diff --git a/other-licenses/snappy/src/snappy.cc b/other-licenses/snappy/src/snappy.cc
new file mode 100644
index 0000000000..57df3f11fc
--- /dev/null
+++ b/other-licenses/snappy/src/snappy.cc
@@ -0,0 +1,2193 @@
+// Copyright 2005 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "snappy-internal.h"
+#include "snappy-sinksource.h"
+#include "snappy.h"
+
+#if !defined(SNAPPY_HAVE_SSSE3)
+// __SSSE3__ is defined by GCC and Clang. Visual Studio doesn't target SIMD
+// support between SSE2 and AVX (so SSSE3 instructions require AVX support), and
+// defines __AVX__ when AVX support is available.
+#if defined(__SSSE3__) || defined(__AVX__)
+#define SNAPPY_HAVE_SSSE3 1
+#else
+#define SNAPPY_HAVE_SSSE3 0
+#endif
+#endif // !defined(SNAPPY_HAVE_SSSE3)
+
+#if !defined(SNAPPY_HAVE_BMI2)
+// __BMI2__ is defined by GCC and Clang. Visual Studio doesn't target BMI2
+// specifically, but it does define __AVX2__ when AVX2 support is available.
+// Fortunately, AVX2 was introduced in Haswell, just like BMI2.
+//
+// BMI2 is not defined as a subset of AVX2 (unlike SSSE3 and AVX above). So,
+// GCC and Clang can build code with AVX2 enabled but BMI2 disabled, in which
+// case issuing BMI2 instructions results in a compiler error.
+#if defined(__BMI2__) || (defined(_MSC_VER) && defined(__AVX2__))
+#define SNAPPY_HAVE_BMI2 1
+#else
+#define SNAPPY_HAVE_BMI2 0
+#endif
+#endif // !defined(SNAPPY_HAVE_BMI2)
+
+#if SNAPPY_HAVE_SSSE3
+// Please do not replace with <x86intrin.h>. or with headers that assume more
+// advanced SSE versions without checking with all the OWNERS.
+#include <tmmintrin.h>
+#endif
+
+#if SNAPPY_HAVE_BMI2
+// Please do not replace with <x86intrin.h>. or with headers that assume more
+// advanced SSE versions without checking with all the OWNERS.
+#include <immintrin.h>
+#endif
+
+#include <algorithm>
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <cstdio>
+#include <cstring>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace snappy {
+
+namespace {
+
+// The amount of slop bytes writers are using for unconditional copies.
+constexpr int kSlopBytes = 64;
+
+using internal::char_table;
+using internal::COPY_1_BYTE_OFFSET;
+using internal::COPY_2_BYTE_OFFSET;
+using internal::COPY_4_BYTE_OFFSET;
+using internal::kMaximumTagLength;
+using internal::LITERAL;
+
+// We translate the information encoded in a tag through a lookup table to a
+// format that requires fewer instructions to decode. Effectively we store
+// the length minus the tag part of the offset. The lowest significant byte
+// thus stores the length. While total length - offset is given by
+// entry - ExtractOffset(type). The nice thing is that the subtraction
+// immediately sets the flags for the necessary check that offset >= length.
+// This folds the cmp with sub. We engineer the long literals and copy-4 to
+// always fail this check, so their presence doesn't affect the fast path.
+// To prevent literals from triggering the guard against offset < length (offset
+// does not apply to literals) the table is giving them a spurious offset of
+// 256.
+inline constexpr int16_t MakeEntry(int16_t len, int16_t offset) {
+ return len - (offset << 8);
+}
+
+inline constexpr int16_t LengthMinusOffset(int data, int type) {
+ return type == 3 ? 0xFF // copy-4 (or type == 3)
+ : type == 2 ? MakeEntry(data + 1, 0) // copy-2
+ : type == 1 ? MakeEntry((data & 7) + 4, data >> 3) // copy-1
+ : data < 60 ? MakeEntry(data + 1, 1) // note spurious offset.
+ : 0xFF; // long literal
+}
+
+inline constexpr int16_t LengthMinusOffset(uint8_t tag) {
+ return LengthMinusOffset(tag >> 2, tag & 3);
+}
+
+template <size_t... Ints>
+struct index_sequence {};
+
+template <std::size_t N, size_t... Is>
+struct make_index_sequence : make_index_sequence<N - 1, N - 1, Is...> {};
+
+template <size_t... Is>
+struct make_index_sequence<0, Is...> : index_sequence<Is...> {};
+
+template <size_t... seq>
+constexpr std::array<int16_t, 256> MakeTable(index_sequence<seq...>) {
+ return std::array<int16_t, 256>{LengthMinusOffset(seq)...};
+}
+
+// We maximally co-locate the two tables so that only one register needs to be
+// reserved for the table address.
+struct {
+ alignas(64) const std::array<int16_t, 256> length_minus_offset;
+ uint32_t extract_masks[4]; // Used for extracting offset based on tag type.
+} table = {MakeTable(make_index_sequence<256>{}), {0, 0xFF, 0xFFFF, 0}};
+
+// Any hash function will produce a valid compressed bitstream, but a good
+// hash function reduces the number of collisions and thus yields better
+// compression for compressible input, and more speed for incompressible
+// input. Of course, it doesn't hurt if the hash function is reasonably fast
+// either, as it gets called a lot.
+inline uint32_t HashBytes(uint32_t bytes, uint32_t mask) {
+ constexpr uint32_t kMagic = 0x1e35a7bd;
+ return ((kMagic * bytes) >> (32 - kMaxHashTableBits)) & mask;
+}
+
+} // namespace
+
+size_t MaxCompressedLength(size_t source_bytes) {
+ // Compressed data can be defined as:
+ // compressed := item* literal*
+ // item := literal* copy
+ //
+ // The trailing literal sequence has a space blowup of at most 62/60
+ // since a literal of length 60 needs one tag byte + one extra byte
+ // for length information.
+ //
+ // Item blowup is trickier to measure. Suppose the "copy" op copies
+ // 4 bytes of data. Because of a special check in the encoding code,
+ // we produce a 4-byte copy only if the offset is < 65536. Therefore
+ // the copy op takes 3 bytes to encode, and this type of item leads
+ // to at most the 62/60 blowup for representing literals.
+ //
+ // Suppose the "copy" op copies 5 bytes of data. If the offset is big
+ // enough, it will take 5 bytes to encode the copy op. Therefore the
+ // worst case here is a one-byte literal followed by a five-byte copy.
+ // I.e., 6 bytes of input turn into 7 bytes of "compressed" data.
+ //
+ // This last factor dominates the blowup, so the final estimate is:
+ return 32 + source_bytes + source_bytes / 6;
+}
+
+namespace {
+
+void UnalignedCopy64(const void* src, void* dst) {
+ char tmp[8];
+ std::memcpy(tmp, src, 8);
+ std::memcpy(dst, tmp, 8);
+}
+
+void UnalignedCopy128(const void* src, void* dst) {
+ // std::memcpy() gets vectorized when the appropriate compiler options are
+ // used. For example, x86 compilers targeting SSE2+ will optimize to an SSE2
+ // load and store.
+ char tmp[16];
+ std::memcpy(tmp, src, 16);
+ std::memcpy(dst, tmp, 16);
+}
+
+template <bool use_16bytes_chunk>
+inline void ConditionalUnalignedCopy128(const char* src, char* dst) {
+ if (use_16bytes_chunk) {
+ UnalignedCopy128(src, dst);
+ } else {
+ UnalignedCopy64(src, dst);
+ UnalignedCopy64(src + 8, dst + 8);
+ }
+}
+
+// Copy [src, src+(op_limit-op)) to [op, (op_limit-op)) a byte at a time. Used
+// for handling COPY operations where the input and output regions may overlap.
+// For example, suppose:
+// src == "ab"
+// op == src + 2
+// op_limit == op + 20
+// After IncrementalCopySlow(src, op, op_limit), the result will have eleven
+// copies of "ab"
+// ababababababababababab
+// Note that this does not match the semantics of either std::memcpy() or
+// std::memmove().
+inline char* IncrementalCopySlow(const char* src, char* op,
+ char* const op_limit) {
+ // TODO: Remove pragma when LLVM is aware this
+ // function is only called in cold regions and when cold regions don't get
+ // vectorized or unrolled.
+#ifdef __clang__
+#pragma clang loop unroll(disable)
+#endif
+ while (op < op_limit) {
+ *op++ = *src++;
+ }
+ return op_limit;
+}
+
+#if SNAPPY_HAVE_SSSE3
+
+// Computes the bytes for shuffle control mask (please read comments on
+// 'pattern_generation_masks' as well) for the given index_offset and
+// pattern_size. For example, when the 'offset' is 6, it will generate a
+// repeating pattern of size 6. So, the first 16 byte indexes will correspond to
+// the pattern-bytes {0, 1, 2, 3, 4, 5, 0, 1, 2, 3, 4, 5, 0, 1, 2, 3} and the
+// next 16 byte indexes will correspond to the pattern-bytes {4, 5, 0, 1, 2, 3,
+// 4, 5, 0, 1, 2, 3, 4, 5, 0, 1}. These byte index sequences are generated by
+// calling MakePatternMaskBytes(0, 6, index_sequence<16>()) and
+// MakePatternMaskBytes(16, 6, index_sequence<16>()) respectively.
+template <size_t... indexes>
+inline constexpr std::array<char, sizeof...(indexes)> MakePatternMaskBytes(
+ int index_offset, int pattern_size, index_sequence<indexes...>) {
+ return {static_cast<char>((index_offset + indexes) % pattern_size)...};
+}
+
+// Computes the shuffle control mask bytes array for given pattern-sizes and
+// returns an array.
+template <size_t... pattern_sizes_minus_one>
+inline constexpr std::array<std::array<char, sizeof(__m128i)>,
+ sizeof...(pattern_sizes_minus_one)>
+MakePatternMaskBytesTable(int index_offset,
+ index_sequence<pattern_sizes_minus_one...>) {
+ return {MakePatternMaskBytes(
+ index_offset, pattern_sizes_minus_one + 1,
+ make_index_sequence</*indexes=*/sizeof(__m128i)>())...};
+}
+
+// This is an array of shuffle control masks that can be used as the source
+// operand for PSHUFB to permute the contents of the destination XMM register
+// into a repeating byte pattern.
+alignas(16) constexpr std::array<std::array<char, sizeof(__m128i)>,
+ 16> pattern_generation_masks =
+ MakePatternMaskBytesTable(
+ /*index_offset=*/0,
+ /*pattern_sizes_minus_one=*/make_index_sequence<16>());
+
+// Similar to 'pattern_generation_masks', this table is used to "rotate" the
+// pattern so that we can copy the *next 16 bytes* consistent with the pattern.
+// Basically, pattern_reshuffle_masks is a continuation of
+// pattern_generation_masks. It follows that, pattern_reshuffle_masks is same as
+// pattern_generation_masks for offsets 1, 2, 4, 8 and 16.
+alignas(16) constexpr std::array<std::array<char, sizeof(__m128i)>,
+ 16> pattern_reshuffle_masks =
+ MakePatternMaskBytesTable(
+ /*index_offset=*/16,
+ /*pattern_sizes_minus_one=*/make_index_sequence<16>());
+
+SNAPPY_ATTRIBUTE_ALWAYS_INLINE
+static inline __m128i LoadPattern(const char* src, const size_t pattern_size) {
+ __m128i generation_mask = _mm_load_si128(reinterpret_cast<const __m128i*>(
+ pattern_generation_masks[pattern_size - 1].data()));
+ // Uninitialized bytes are masked out by the shuffle mask.
+ // TODO: remove annotation and macro defs once MSan is fixed.
+ SNAPPY_ANNOTATE_MEMORY_IS_INITIALIZED(src + pattern_size, 16 - pattern_size);
+ return _mm_shuffle_epi8(
+ _mm_loadu_si128(reinterpret_cast<const __m128i*>(src)), generation_mask);
+}
+
+SNAPPY_ATTRIBUTE_ALWAYS_INLINE
+static inline std::pair<__m128i /* pattern */, __m128i /* reshuffle_mask */>
+LoadPatternAndReshuffleMask(const char* src, const size_t pattern_size) {
+ __m128i pattern = LoadPattern(src, pattern_size);
+
+ // This mask will generate the next 16 bytes in-place. Doing so enables us to
+ // write data by at most 4 _mm_storeu_si128.
+ //
+ // For example, suppose pattern is: abcdefabcdefabcd
+ // Shuffling with this mask will generate: efabcdefabcdefab
+ // Shuffling again will generate: cdefabcdefabcdef
+ __m128i reshuffle_mask = _mm_load_si128(reinterpret_cast<const __m128i*>(
+ pattern_reshuffle_masks[pattern_size - 1].data()));
+ return {pattern, reshuffle_mask};
+}
+
+#endif // SNAPPY_HAVE_SSSE3
+
+// Fallback for when we need to copy while extending the pattern, for example
+// copying 10 bytes from 3 positions back abc -> abcabcabcabca.
+//
+// REQUIRES: [dst - offset, dst + 64) is a valid address range.
+SNAPPY_ATTRIBUTE_ALWAYS_INLINE
+static inline bool Copy64BytesWithPatternExtension(char* dst, size_t offset) {
+#if SNAPPY_HAVE_SSSE3
+ if (SNAPPY_PREDICT_TRUE(offset <= 16)) {
+ switch (offset) {
+ case 0:
+ return false;
+ case 1: {
+ std::memset(dst, dst[-1], 64);
+ return true;
+ }
+ case 2:
+ case 4:
+ case 8:
+ case 16: {
+ __m128i pattern = LoadPattern(dst - offset, offset);
+ for (int i = 0; i < 4; i++) {
+ _mm_storeu_si128(reinterpret_cast<__m128i*>(dst + 16 * i), pattern);
+ }
+ return true;
+ }
+ default: {
+ auto pattern_and_reshuffle_mask =
+ LoadPatternAndReshuffleMask(dst - offset, offset);
+ __m128i pattern = pattern_and_reshuffle_mask.first;
+ __m128i reshuffle_mask = pattern_and_reshuffle_mask.second;
+ for (int i = 0; i < 4; i++) {
+ _mm_storeu_si128(reinterpret_cast<__m128i*>(dst + 16 * i), pattern);
+ pattern = _mm_shuffle_epi8(pattern, reshuffle_mask);
+ }
+ return true;
+ }
+ }
+ }
+#else
+ if (SNAPPY_PREDICT_TRUE(offset < 16)) {
+ if (SNAPPY_PREDICT_FALSE(offset == 0)) return false;
+ // Extend the pattern to the first 16 bytes.
+ for (int i = 0; i < 16; i++) dst[i] = (dst - offset)[i];
+ // Find a multiple of pattern >= 16.
+ static std::array<uint8_t, 16> pattern_sizes = []() {
+ std::array<uint8_t, 16> res;
+ for (int i = 1; i < 16; i++) res[i] = (16 / i + 1) * i;
+ return res;
+ }();
+ offset = pattern_sizes[offset];
+ for (int i = 1; i < 4; i++) {
+ std::memcpy(dst + i * 16, dst + i * 16 - offset, 16);
+ }
+ return true;
+ }
+#endif // SNAPPY_HAVE_SSSE3
+
+ // Very rare.
+ for (int i = 0; i < 4; i++) {
+ std::memcpy(dst + i * 16, dst + i * 16 - offset, 16);
+ }
+ return true;
+}
+
+// Copy [src, src+(op_limit-op)) to [op, op_limit) but faster than
+// IncrementalCopySlow. buf_limit is the address past the end of the writable
+// region of the buffer.
+inline char* IncrementalCopy(const char* src, char* op, char* const op_limit,
+ char* const buf_limit) {
+#if SNAPPY_HAVE_SSSE3
+ constexpr int big_pattern_size_lower_bound = 16;
+#else
+ constexpr int big_pattern_size_lower_bound = 8;
+#endif
+
+ // Terminology:
+ //
+ // slop = buf_limit - op
+ // pat = op - src
+ // len = op_limit - op
+ assert(src < op);
+ assert(op < op_limit);
+ assert(op_limit <= buf_limit);
+ // NOTE: The copy tags use 3 or 6 bits to store the copy length, so len <= 64.
+ assert(op_limit - op <= 64);
+ // NOTE: In practice the compressor always emits len >= 4, so it is ok to
+ // assume that to optimize this function, but this is not guaranteed by the
+ // compression format, so we have to also handle len < 4 in case the input
+ // does not satisfy these conditions.
+
+ size_t pattern_size = op - src;
+ // The cases are split into different branches to allow the branch predictor,
+ // FDO, and static prediction hints to work better. For each input we list the
+ // ratio of invocations that match each condition.
+ //
+ // input slop < 16 pat < 8 len > 16
+ // ------------------------------------------
+ // html|html4|cp 0% 1.01% 27.73%
+ // urls 0% 0.88% 14.79%
+ // jpg 0% 64.29% 7.14%
+ // pdf 0% 2.56% 58.06%
+ // txt[1-4] 0% 0.23% 0.97%
+ // pb 0% 0.96% 13.88%
+ // bin 0.01% 22.27% 41.17%
+ //
+ // It is very rare that we don't have enough slop for doing block copies. It
+ // is also rare that we need to expand a pattern. Small patterns are common
+ // for incompressible formats and for those we are plenty fast already.
+ // Lengths are normally not greater than 16 but they vary depending on the
+ // input. In general if we always predict len <= 16 it would be an ok
+ // prediction.
+ //
+ // In order to be fast we want a pattern >= 16 bytes (or 8 bytes in non-SSE)
+ // and an unrolled loop copying 1x 16 bytes (or 2x 8 bytes in non-SSE) at a
+ // time.
+
+ // Handle the uncommon case where pattern is less than 16 (or 8 in non-SSE)
+ // bytes.
+ if (pattern_size < big_pattern_size_lower_bound) {
+#if SNAPPY_HAVE_SSSE3
+ // Load the first eight bytes into an 128-bit XMM register, then use PSHUFB
+ // to permute the register's contents in-place into a repeating sequence of
+ // the first "pattern_size" bytes.
+ // For example, suppose:
+ // src == "abc"
+ // op == op + 3
+ // After _mm_shuffle_epi8(), "pattern" will have five copies of "abc"
+ // followed by one byte of slop: abcabcabcabcabca.
+ //
+ // The non-SSE fallback implementation suffers from store-forwarding stalls
+ // because its loads and stores partly overlap. By expanding the pattern
+ // in-place, we avoid the penalty.
+
+ // Typically, the op_limit is the gating factor so try to simplify the loop
+ // based on that.
+ if (SNAPPY_PREDICT_TRUE(op_limit <= buf_limit - 15)) {
+ auto pattern_and_reshuffle_mask =
+ LoadPatternAndReshuffleMask(src, pattern_size);
+ __m128i pattern = pattern_and_reshuffle_mask.first;
+ __m128i reshuffle_mask = pattern_and_reshuffle_mask.second;
+
+ // There is at least one, and at most four 16-byte blocks. Writing four
+ // conditionals instead of a loop allows FDO to layout the code with
+ // respect to the actual probabilities of each length.
+ // TODO: Replace with loop with trip count hint.
+ _mm_storeu_si128(reinterpret_cast<__m128i*>(op), pattern);
+
+ if (op + 16 < op_limit) {
+ pattern = _mm_shuffle_epi8(pattern, reshuffle_mask);
+ _mm_storeu_si128(reinterpret_cast<__m128i*>(op + 16), pattern);
+ }
+ if (op + 32 < op_limit) {
+ pattern = _mm_shuffle_epi8(pattern, reshuffle_mask);
+ _mm_storeu_si128(reinterpret_cast<__m128i*>(op + 32), pattern);
+ }
+ if (op + 48 < op_limit) {
+ pattern = _mm_shuffle_epi8(pattern, reshuffle_mask);
+ _mm_storeu_si128(reinterpret_cast<__m128i*>(op + 48), pattern);
+ }
+ return op_limit;
+ }
+ char* const op_end = buf_limit - 15;
+ if (SNAPPY_PREDICT_TRUE(op < op_end)) {
+ auto pattern_and_reshuffle_mask =
+ LoadPatternAndReshuffleMask(src, pattern_size);
+ __m128i pattern = pattern_and_reshuffle_mask.first;
+ __m128i reshuffle_mask = pattern_and_reshuffle_mask.second;
+
+ // This code path is relatively cold however so we save code size
+ // by avoiding unrolling and vectorizing.
+ //
+ // TODO: Remove pragma when when cold regions don't get
+ // vectorized or unrolled.
+#ifdef __clang__
+#pragma clang loop unroll(disable)
+#endif
+ do {
+ _mm_storeu_si128(reinterpret_cast<__m128i*>(op), pattern);
+ pattern = _mm_shuffle_epi8(pattern, reshuffle_mask);
+ op += 16;
+ } while (SNAPPY_PREDICT_TRUE(op < op_end));
+ }
+ return IncrementalCopySlow(op - pattern_size, op, op_limit);
+#else // !SNAPPY_HAVE_SSSE3
+ // If plenty of buffer space remains, expand the pattern to at least 8
+ // bytes. The way the following loop is written, we need 8 bytes of buffer
+ // space if pattern_size >= 4, 11 bytes if pattern_size is 1 or 3, and 10
+ // bytes if pattern_size is 2. Precisely encoding that is probably not
+ // worthwhile; instead, invoke the slow path if we cannot write 11 bytes
+ // (because 11 are required in the worst case).
+ if (SNAPPY_PREDICT_TRUE(op <= buf_limit - 11)) {
+ while (pattern_size < 8) {
+ UnalignedCopy64(src, op);
+ op += pattern_size;
+ pattern_size *= 2;
+ }
+ if (SNAPPY_PREDICT_TRUE(op >= op_limit)) return op_limit;
+ } else {
+ return IncrementalCopySlow(src, op, op_limit);
+ }
+#endif // SNAPPY_HAVE_SSSE3
+ }
+ assert(pattern_size >= big_pattern_size_lower_bound);
+ constexpr bool use_16bytes_chunk = big_pattern_size_lower_bound == 16;
+
+ // Copy 1x 16 bytes (or 2x 8 bytes in non-SSE) at a time. Because op - src can
+ // be < 16 in non-SSE, a single UnalignedCopy128 might overwrite data in op.
+ // UnalignedCopy64 is safe because expanding the pattern to at least 8 bytes
+ // guarantees that op - src >= 8.
+ //
+ // Typically, the op_limit is the gating factor so try to simplify the loop
+ // based on that.
+ if (SNAPPY_PREDICT_TRUE(op_limit <= buf_limit - 15)) {
+ // There is at least one, and at most four 16-byte blocks. Writing four
+ // conditionals instead of a loop allows FDO to layout the code with respect
+ // to the actual probabilities of each length.
+ // TODO: Replace with loop with trip count hint.
+ ConditionalUnalignedCopy128<use_16bytes_chunk>(src, op);
+ if (op + 16 < op_limit) {
+ ConditionalUnalignedCopy128<use_16bytes_chunk>(src + 16, op + 16);
+ }
+ if (op + 32 < op_limit) {
+ ConditionalUnalignedCopy128<use_16bytes_chunk>(src + 32, op + 32);
+ }
+ if (op + 48 < op_limit) {
+ ConditionalUnalignedCopy128<use_16bytes_chunk>(src + 48, op + 48);
+ }
+ return op_limit;
+ }
+
+ // Fall back to doing as much as we can with the available slop in the
+ // buffer. This code path is relatively cold however so we save code size by
+ // avoiding unrolling and vectorizing.
+ //
+ // TODO: Remove pragma when when cold regions don't get vectorized
+ // or unrolled.
+#ifdef __clang__
+#pragma clang loop unroll(disable)
+#endif
+ for (char* op_end = buf_limit - 16; op < op_end; op += 16, src += 16) {
+ ConditionalUnalignedCopy128<use_16bytes_chunk>(src, op);
+ }
+ if (op >= op_limit) return op_limit;
+
+ // We only take this branch if we didn't have enough slop and we can do a
+ // single 8 byte copy.
+ if (SNAPPY_PREDICT_FALSE(op <= buf_limit - 8)) {
+ UnalignedCopy64(src, op);
+ src += 8;
+ op += 8;
+ }
+ return IncrementalCopySlow(src, op, op_limit);
+}
+
+} // namespace
+
+template <bool allow_fast_path>
+static inline char* EmitLiteral(char* op, const char* literal, int len) {
+ // The vast majority of copies are below 16 bytes, for which a
+ // call to std::memcpy() is overkill. This fast path can sometimes
+ // copy up to 15 bytes too much, but that is okay in the
+ // main loop, since we have a bit to go on for both sides:
+ //
+ // - The input will always have kInputMarginBytes = 15 extra
+ // available bytes, as long as we're in the main loop, and
+ // if not, allow_fast_path = false.
+ // - The output will always have 32 spare bytes (see
+ // MaxCompressedLength).
+ assert(len > 0); // Zero-length literals are disallowed
+ int n = len - 1;
+ if (allow_fast_path && len <= 16) {
+ // Fits in tag byte
+ *op++ = LITERAL | (n << 2);
+
+ UnalignedCopy128(literal, op);
+ return op + len;
+ }
+
+ if (n < 60) {
+ // Fits in tag byte
+ *op++ = LITERAL | (n << 2);
+ } else {
+ int count = (Bits::Log2Floor(n) >> 3) + 1;
+ assert(count >= 1);
+ assert(count <= 4);
+ *op++ = LITERAL | ((59 + count) << 2);
+ // Encode in upcoming bytes.
+ // Write 4 bytes, though we may care about only 1 of them. The output buffer
+ // is guaranteed to have at least 3 more spaces left as 'len >= 61' holds
+ // here and there is a std::memcpy() of size 'len' below.
+ LittleEndian::Store32(op, n);
+ op += count;
+ }
+ std::memcpy(op, literal, len);
+ return op + len;
+}
+
+template <bool len_less_than_12>
+static inline char* EmitCopyAtMost64(char* op, size_t offset, size_t len) {
+ assert(len <= 64);
+ assert(len >= 4);
+ assert(offset < 65536);
+ assert(len_less_than_12 == (len < 12));
+
+ if (len_less_than_12) {
+ uint32_t u = (len << 2) + (offset << 8);
+ uint32_t copy1 = COPY_1_BYTE_OFFSET - (4 << 2) + ((offset >> 3) & 0xe0);
+ uint32_t copy2 = COPY_2_BYTE_OFFSET - (1 << 2);
+ // It turns out that offset < 2048 is a difficult to predict branch.
+ // `perf record` shows this is the highest percentage of branch misses in
+ // benchmarks. This code produces branch free code, the data dependency
+ // chain that bottlenecks the throughput is so long that a few extra
+ // instructions are completely free (IPC << 6 because of data deps).
+ u += offset < 2048 ? copy1 : copy2;
+ LittleEndian::Store32(op, u);
+ op += offset < 2048 ? 2 : 3;
+ } else {
+ // Write 4 bytes, though we only care about 3 of them. The output buffer
+ // is required to have some slack, so the extra byte won't overrun it.
+ uint32_t u = COPY_2_BYTE_OFFSET + ((len - 1) << 2) + (offset << 8);
+ LittleEndian::Store32(op, u);
+ op += 3;
+ }
+ return op;
+}
+
+template <bool len_less_than_12>
+static inline char* EmitCopy(char* op, size_t offset, size_t len) {
+ assert(len_less_than_12 == (len < 12));
+ if (len_less_than_12) {
+ return EmitCopyAtMost64</*len_less_than_12=*/true>(op, offset, len);
+ } else {
+ // A special case for len <= 64 might help, but so far measurements suggest
+ // it's in the noise.
+
+ // Emit 64 byte copies but make sure to keep at least four bytes reserved.
+ while (SNAPPY_PREDICT_FALSE(len >= 68)) {
+ op = EmitCopyAtMost64</*len_less_than_12=*/false>(op, offset, 64);
+ len -= 64;
+ }
+
+ // One or two copies will now finish the job.
+ if (len > 64) {
+ op = EmitCopyAtMost64</*len_less_than_12=*/false>(op, offset, 60);
+ len -= 60;
+ }
+
+ // Emit remainder.
+ if (len < 12) {
+ op = EmitCopyAtMost64</*len_less_than_12=*/true>(op, offset, len);
+ } else {
+ op = EmitCopyAtMost64</*len_less_than_12=*/false>(op, offset, len);
+ }
+ return op;
+ }
+}
+
+bool GetUncompressedLength(const char* start, size_t n, size_t* result) {
+ uint32_t v = 0;
+ const char* limit = start + n;
+ if (Varint::Parse32WithLimit(start, limit, &v) != NULL) {
+ *result = v;
+ return true;
+ } else {
+ return false;
+ }
+}
+
+namespace {
+uint32_t CalculateTableSize(uint32_t input_size) {
+ static_assert(
+ kMaxHashTableSize >= kMinHashTableSize,
+ "kMaxHashTableSize should be greater or equal to kMinHashTableSize.");
+ if (input_size > kMaxHashTableSize) {
+ return kMaxHashTableSize;
+ }
+ if (input_size < kMinHashTableSize) {
+ return kMinHashTableSize;
+ }
+ // This is equivalent to Log2Ceiling(input_size), assuming input_size > 1.
+ // 2 << Log2Floor(x - 1) is equivalent to 1 << (1 + Log2Floor(x - 1)).
+ return 2u << Bits::Log2Floor(input_size - 1);
+}
+} // namespace
+
+namespace internal {
+WorkingMemory::WorkingMemory(size_t input_size) {
+ const size_t max_fragment_size = std::min(input_size, kBlockSize);
+ const size_t table_size = CalculateTableSize(max_fragment_size);
+ size_ = table_size * sizeof(*table_) + max_fragment_size +
+ MaxCompressedLength(max_fragment_size);
+ mem_ = std::allocator<char>().allocate(size_);
+ table_ = reinterpret_cast<uint16_t*>(mem_);
+ input_ = mem_ + table_size * sizeof(*table_);
+ output_ = input_ + max_fragment_size;
+}
+
+WorkingMemory::~WorkingMemory() {
+ std::allocator<char>().deallocate(mem_, size_);
+}
+
+uint16_t* WorkingMemory::GetHashTable(size_t fragment_size,
+ int* table_size) const {
+ const size_t htsize = CalculateTableSize(fragment_size);
+ memset(table_, 0, htsize * sizeof(*table_));
+ *table_size = htsize;
+ return table_;
+}
+} // end namespace internal
+
+// Flat array compression that does not emit the "uncompressed length"
+// prefix. Compresses "input" string to the "*op" buffer.
+//
+// REQUIRES: "input" is at most "kBlockSize" bytes long.
+// REQUIRES: "op" points to an array of memory that is at least
+// "MaxCompressedLength(input.size())" in size.
+// REQUIRES: All elements in "table[0..table_size-1]" are initialized to zero.
+// REQUIRES: "table_size" is a power of two
+//
+// Returns an "end" pointer into "op" buffer.
+// "end - op" is the compressed size of "input".
+namespace internal {
+char* CompressFragment(const char* input, size_t input_size, char* op,
+ uint16_t* table, const int table_size) {
+ // "ip" is the input pointer, and "op" is the output pointer.
+ const char* ip = input;
+ assert(input_size <= kBlockSize);
+ assert((table_size & (table_size - 1)) == 0); // table must be power of two
+ const uint32_t mask = table_size - 1;
+ const char* ip_end = input + input_size;
+ const char* base_ip = ip;
+
+ const size_t kInputMarginBytes = 15;
+ if (SNAPPY_PREDICT_TRUE(input_size >= kInputMarginBytes)) {
+ const char* ip_limit = input + input_size - kInputMarginBytes;
+
+ for (uint32_t preload = LittleEndian::Load32(ip + 1);;) {
+ // Bytes in [next_emit, ip) will be emitted as literal bytes. Or
+ // [next_emit, ip_end) after the main loop.
+ const char* next_emit = ip++;
+ uint64_t data = LittleEndian::Load64(ip);
+ // The body of this loop calls EmitLiteral once and then EmitCopy one or
+ // more times. (The exception is that when we're close to exhausting
+ // the input we goto emit_remainder.)
+ //
+ // In the first iteration of this loop we're just starting, so
+ // there's nothing to copy, so calling EmitLiteral once is
+ // necessary. And we only start a new iteration when the
+ // current iteration has determined that a call to EmitLiteral will
+ // precede the next call to EmitCopy (if any).
+ //
+ // Step 1: Scan forward in the input looking for a 4-byte-long match.
+ // If we get close to exhausting the input then goto emit_remainder.
+ //
+ // Heuristic match skipping: If 32 bytes are scanned with no matches
+ // found, start looking only at every other byte. If 32 more bytes are
+ // scanned (or skipped), look at every third byte, etc.. When a match is
+ // found, immediately go back to looking at every byte. This is a small
+ // loss (~5% performance, ~0.1% density) for compressible data due to more
+ // bookkeeping, but for non-compressible data (such as JPEG) it's a huge
+ // win since the compressor quickly "realizes" the data is incompressible
+ // and doesn't bother looking for matches everywhere.
+ //
+ // The "skip" variable keeps track of how many bytes there are since the
+ // last match; dividing it by 32 (ie. right-shifting by five) gives the
+ // number of bytes to move ahead for each iteration.
+ uint32_t skip = 32;
+
+ const char* candidate;
+ if (ip_limit - ip >= 16) {
+ auto delta = ip - base_ip;
+ for (int j = 0; j < 4; ++j) {
+ for (int k = 0; k < 4; ++k) {
+ int i = 4 * j + k;
+ // These for-loops are meant to be unrolled. So we can freely
+ // special case the first iteration to use the value already
+ // loaded in preload.
+ uint32_t dword = i == 0 ? preload : static_cast<uint32_t>(data);
+ assert(dword == LittleEndian::Load32(ip + i));
+ uint32_t hash = HashBytes(dword, mask);
+ candidate = base_ip + table[hash];
+ assert(candidate >= base_ip);
+ assert(candidate < ip + i);
+ table[hash] = delta + i;
+ if (SNAPPY_PREDICT_FALSE(LittleEndian::Load32(candidate) == dword)) {
+ *op = LITERAL | (i << 2);
+ UnalignedCopy128(next_emit, op + 1);
+ ip += i;
+ op = op + i + 2;
+ goto emit_match;
+ }
+ data >>= 8;
+ }
+ data = LittleEndian::Load64(ip + 4 * j + 4);
+ }
+ ip += 16;
+ skip += 16;
+ }
+ while (true) {
+ assert(static_cast<uint32_t>(data) == LittleEndian::Load32(ip));
+ uint32_t hash = HashBytes(data, mask);
+ uint32_t bytes_between_hash_lookups = skip >> 5;
+ skip += bytes_between_hash_lookups;
+ const char* next_ip = ip + bytes_between_hash_lookups;
+ if (SNAPPY_PREDICT_FALSE(next_ip > ip_limit)) {
+ ip = next_emit;
+ goto emit_remainder;
+ }
+ candidate = base_ip + table[hash];
+ assert(candidate >= base_ip);
+ assert(candidate < ip);
+
+ table[hash] = ip - base_ip;
+ if (SNAPPY_PREDICT_FALSE(static_cast<uint32_t>(data) ==
+ LittleEndian::Load32(candidate))) {
+ break;
+ }
+ data = LittleEndian::Load32(next_ip);
+ ip = next_ip;
+ }
+
+ // Step 2: A 4-byte match has been found. We'll later see if more
+ // than 4 bytes match. But, prior to the match, input
+ // bytes [next_emit, ip) are unmatched. Emit them as "literal bytes."
+ assert(next_emit + 16 <= ip_end);
+ op = EmitLiteral</*allow_fast_path=*/true>(op, next_emit, ip - next_emit);
+
+ // Step 3: Call EmitCopy, and then see if another EmitCopy could
+ // be our next move. Repeat until we find no match for the
+ // input immediately after what was consumed by the last EmitCopy call.
+ //
+ // If we exit this loop normally then we need to call EmitLiteral next,
+ // though we don't yet know how big the literal will be. We handle that
+ // by proceeding to the next iteration of the main loop. We also can exit
+ // this loop via goto if we get close to exhausting the input.
+ emit_match:
+ do {
+ // We have a 4-byte match at ip, and no need to emit any
+ // "literal bytes" prior to ip.
+ const char* base = ip;
+ std::pair<size_t, bool> p =
+ FindMatchLength(candidate + 4, ip + 4, ip_end, &data);
+ size_t matched = 4 + p.first;
+ ip += matched;
+ size_t offset = base - candidate;
+ assert(0 == memcmp(base, candidate, matched));
+ if (p.second) {
+ op = EmitCopy</*len_less_than_12=*/true>(op, offset, matched);
+ } else {
+ op = EmitCopy</*len_less_than_12=*/false>(op, offset, matched);
+ }
+ if (SNAPPY_PREDICT_FALSE(ip >= ip_limit)) {
+ goto emit_remainder;
+ }
+ // Expect 5 bytes to match
+ assert((data & 0xFFFFFFFFFF) ==
+ (LittleEndian::Load64(ip) & 0xFFFFFFFFFF));
+ // We are now looking for a 4-byte match again. We read
+ // table[Hash(ip, shift)] for that. To improve compression,
+ // we also update table[Hash(ip - 1, mask)] and table[Hash(ip, mask)].
+ table[HashBytes(LittleEndian::Load32(ip - 1), mask)] = ip - base_ip - 1;
+ uint32_t hash = HashBytes(data, mask);
+ candidate = base_ip + table[hash];
+ table[hash] = ip - base_ip;
+ // Measurements on the benchmarks have shown the following probabilities
+ // for the loop to exit (ie. avg. number of iterations is reciprocal).
+ // BM_Flat/6 txt1 p = 0.3-0.4
+ // BM_Flat/7 txt2 p = 0.35
+ // BM_Flat/8 txt3 p = 0.3-0.4
+ // BM_Flat/9 txt3 p = 0.34-0.4
+ // BM_Flat/10 pb p = 0.4
+ // BM_Flat/11 gaviota p = 0.1
+ // BM_Flat/12 cp p = 0.5
+ // BM_Flat/13 c p = 0.3
+ } while (static_cast<uint32_t>(data) == LittleEndian::Load32(candidate));
+ // Because the least significant 5 bytes matched, we can utilize data
+ // for the next iteration.
+ preload = data >> 8;
+ }
+ }
+
+emit_remainder:
+ // Emit the remaining bytes as a literal
+ if (ip < ip_end) {
+ op = EmitLiteral</*allow_fast_path=*/false>(op, ip, ip_end - ip);
+ }
+
+ return op;
+}
+} // end namespace internal
+
+// Called back at avery compression call to trace parameters and sizes.
+static inline void Report(const char *algorithm, size_t compressed_size,
+ size_t uncompressed_size) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)algorithm;
+ (void)compressed_size;
+ (void)uncompressed_size;
+}
+
+// Signature of output types needed by decompression code.
+// The decompression code is templatized on a type that obeys this
+// signature so that we do not pay virtual function call overhead in
+// the middle of a tight decompression loop.
+//
+// class DecompressionWriter {
+// public:
+// // Called before decompression
+// void SetExpectedLength(size_t length);
+//
+// // For performance a writer may choose to donate the cursor variable to the
+// // decompression function. The decompression will inject it in all its
+// // function calls to the writer. Keeping the important output cursor as a
+// // function local stack variable allows the compiler to keep it in
+// // register, which greatly aids performance by avoiding loads and stores of
+// // this variable in the fast path loop iterations.
+// T GetOutputPtr() const;
+//
+// // At end of decompression the loop donates the ownership of the cursor
+// // variable back to the writer by calling this function.
+// void SetOutputPtr(T op);
+//
+// // Called after decompression
+// bool CheckLength() const;
+//
+// // Called repeatedly during decompression
+// // Each function get a pointer to the op (output pointer), that the writer
+// // can use and update. Note it's important that these functions get fully
+// // inlined so that no actual address of the local variable needs to be
+// // taken.
+// bool Append(const char* ip, size_t length, T* op);
+// bool AppendFromSelf(uint32_t offset, size_t length, T* op);
+//
+// // The rules for how TryFastAppend differs from Append are somewhat
+// // convoluted:
+// //
+// // - TryFastAppend is allowed to decline (return false) at any
+// // time, for any reason -- just "return false" would be
+// // a perfectly legal implementation of TryFastAppend.
+// // The intention is for TryFastAppend to allow a fast path
+// // in the common case of a small append.
+// // - TryFastAppend is allowed to read up to <available> bytes
+// // from the input buffer, whereas Append is allowed to read
+// // <length>. However, if it returns true, it must leave
+// // at least five (kMaximumTagLength) bytes in the input buffer
+// // afterwards, so that there is always enough space to read the
+// // next tag without checking for a refill.
+// // - TryFastAppend must always return decline (return false)
+// // if <length> is 61 or more, as in this case the literal length is not
+// // decoded fully. In practice, this should not be a big problem,
+// // as it is unlikely that one would implement a fast path accepting
+// // this much data.
+// //
+// bool TryFastAppend(const char* ip, size_t available, size_t length, T* op);
+// };
+
+static inline uint32_t ExtractLowBytes(uint32_t v, int n) {
+ assert(n >= 0);
+ assert(n <= 4);
+#if SNAPPY_HAVE_BMI2
+ return _bzhi_u32(v, 8 * n);
+#else
+ // This needs to be wider than uint32_t otherwise `mask << 32` will be
+ // undefined.
+ uint64_t mask = 0xffffffff;
+ return v & ~(mask << (8 * n));
+#endif
+}
+
+static inline bool LeftShiftOverflows(uint8_t value, uint32_t shift) {
+ assert(shift < 32);
+ static const uint8_t masks[] = {
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //
+ 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //
+ 0x00, 0x80, 0xc0, 0xe0, 0xf0, 0xf8, 0xfc, 0xfe};
+ return (value & masks[shift]) != 0;
+}
+
+inline bool Copy64BytesWithPatternExtension(ptrdiff_t dst, size_t offset) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)dst;
+ return offset != 0;
+}
+
+void MemCopy(char* dst, const uint8_t* src, size_t size) {
+ std::memcpy(dst, src, size);
+}
+
+void MemCopy(ptrdiff_t dst, const uint8_t* src, size_t size) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)dst;
+ (void)src;
+ (void)size;
+}
+
+void MemMove(char* dst, const void* src, size_t size) {
+ std::memmove(dst, src, size);
+}
+
+void MemMove(ptrdiff_t dst, const void* src, size_t size) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)dst;
+ (void)src;
+ (void)size;
+}
+
+SNAPPY_ATTRIBUTE_ALWAYS_INLINE
+size_t AdvanceToNextTag(const uint8_t** ip_p, size_t* tag) {
+ const uint8_t*& ip = *ip_p;
+ // This section is crucial for the throughput of the decompression loop.
+ // The latency of an iteration is fundamentally constrained by the
+ // following data chain on ip.
+ // ip -> c = Load(ip) -> ip1 = ip + 1 + (c & 3) -> ip = ip1 or ip2
+ // ip2 = ip + 2 + (c >> 2)
+ // This amounts to 8 cycles.
+ // 5 (load) + 1 (c & 3) + 1 (lea ip1, [ip + (c & 3) + 1]) + 1 (cmov)
+ size_t literal_len = *tag >> 2;
+ size_t tag_type = *tag;
+ bool is_literal;
+#if defined(__GNUC__) && defined(__x86_64__) && defined(__GCC_ASM_FLAG_OUTPUTS__)
+ // TODO clang misses the fact that the (c & 3) already correctly
+ // sets the zero flag.
+ asm("and $3, %k[tag_type]\n\t"
+ : [tag_type] "+r"(tag_type), "=@ccz"(is_literal));
+#else
+ tag_type &= 3;
+ is_literal = (tag_type == 0);
+#endif
+ // TODO
+ // This is code is subtle. Loading the values first and then cmov has less
+ // latency then cmov ip and then load. However clang would move the loads
+ // in an optimization phase, volatile prevents this transformation.
+ // Note that we have enough slop bytes (64) that the loads are always valid.
+ size_t tag_literal =
+ static_cast<const volatile uint8_t*>(ip)[1 + literal_len];
+ size_t tag_copy = static_cast<const volatile uint8_t*>(ip)[tag_type];
+ *tag = is_literal ? tag_literal : tag_copy;
+ const uint8_t* ip_copy = ip + 1 + tag_type;
+ const uint8_t* ip_literal = ip + 2 + literal_len;
+ ip = is_literal ? ip_literal : ip_copy;
+#if defined(__GNUC__) && defined(__x86_64__)
+ // TODO Clang is "optimizing" zero-extension (a totally free
+ // operation) this means that after the cmov of tag, it emits another movzb
+ // tag, byte(tag). It really matters as it's on the core chain. This dummy
+ // asm, persuades clang to do the zero-extension at the load (it's automatic)
+ // removing the expensive movzb.
+ asm("" ::"r"(tag_copy));
+#endif
+ return tag_type;
+}
+
+// Extract the offset for copy-1 and copy-2 returns 0 for literals or copy-4.
+inline uint32_t ExtractOffset(uint32_t val, size_t tag_type) {
+ return val & table.extract_masks[tag_type];
+};
+
+// Core decompression loop, when there is enough data available.
+// Decompresses the input buffer [ip, ip_limit) into the output buffer
+// [op, op_limit_min_slop). Returning when either we are too close to the end
+// of the input buffer, or we exceed op_limit_min_slop or when a exceptional
+// tag is encountered (literal of length > 60) or a copy-4.
+// Returns {ip, op} at the points it stopped decoding.
+// TODO This function probably does not need to be inlined, as it
+// should decode large chunks at a time. This allows runtime dispatch to
+// implementations based on CPU capability (BMI2 / perhaps 32 / 64 byte memcpy).
+template <typename T>
+std::pair<const uint8_t*, ptrdiff_t> DecompressBranchless(
+ const uint8_t* ip, const uint8_t* ip_limit, ptrdiff_t op, T op_base,
+ ptrdiff_t op_limit_min_slop) {
+ // We unroll the inner loop twice so we need twice the spare room.
+ op_limit_min_slop -= kSlopBytes;
+ if (2 * (kSlopBytes + 1) < ip_limit - ip && op < op_limit_min_slop) {
+ const uint8_t* const ip_limit_min_slop = ip_limit - 2 * kSlopBytes - 1;
+ ip++;
+ // ip points just past the tag and we are touching at maximum kSlopBytes
+ // in an iteration.
+ size_t tag = ip[-1];
+ do {
+ // The throughput is limited by instructions, unrolling the inner loop
+ // twice reduces the amount of instructions checking limits and also
+ // leads to reduced mov's.
+ for (int i = 0; i < 2; i++) {
+ const uint8_t* old_ip = ip;
+ assert(tag == ip[-1]);
+ // For literals tag_type = 0, hence we will always obtain 0 from
+ // ExtractLowBytes. For literals offset will thus be kLiteralOffset.
+ ptrdiff_t len_min_offset = table.length_minus_offset[tag];
+ size_t tag_type = AdvanceToNextTag(&ip, &tag);
+ uint32_t next = LittleEndian::Load32(old_ip);
+ size_t len = len_min_offset & 0xFF;
+ len_min_offset -= ExtractOffset(next, tag_type);
+ if (SNAPPY_PREDICT_FALSE(len_min_offset > 0)) {
+ if (SNAPPY_PREDICT_FALSE(len & 0x80)) {
+ // Exceptional case (long literal or copy 4).
+ // Actually doing the copy here is negatively impacting the main
+ // loop due to compiler incorrectly allocating a register for
+ // this fallback. Hence we just break.
+ break_loop:
+ ip = old_ip;
+ goto exit;
+ }
+ // Only copy-1 or copy-2 tags can get here.
+ assert(tag_type == 1 || tag_type == 2);
+ std::ptrdiff_t delta = op + len_min_offset - len;
+ // Guard against copies before the buffer start.
+ if (SNAPPY_PREDICT_FALSE(delta < 0 ||
+ !Copy64BytesWithPatternExtension(
+ op_base + op, len - len_min_offset))) {
+ goto break_loop;
+ }
+ op += len;
+ continue;
+ }
+ std::ptrdiff_t delta = op + len_min_offset - len;
+ if (SNAPPY_PREDICT_FALSE(delta < 0)) {
+#if defined(__GNUC__) && defined(__x86_64__)
+ // TODO
+ // When validating, both code path reduced to `op += len`. Ie. this
+ // becomes effectively
+ //
+ // if (delta < 0) if (tag_type != 0) goto break_loop;
+ // op += len;
+ //
+ // The compiler interchanges the predictable and almost always false
+ // first if-statement with the completely unpredictable second
+ // if-statement, putting an unpredictable branch on every iteration.
+ // This empty asm is worth almost 2x, which I think qualifies for an
+ // award for the most load-bearing empty statement.
+ asm("");
+#endif
+
+ // Due to the spurious offset in literals have this will trigger
+ // at the start of a block when op is still smaller than 256.
+ if (tag_type != 0) goto break_loop;
+ MemCopy(op_base + op, old_ip, 64);
+ op += len;
+ continue;
+ }
+
+ // For copies we need to copy from op_base + delta, for literals
+ // we need to copy from ip instead of from the stream.
+ const void* from =
+ tag_type ? reinterpret_cast<void*>(op_base + delta) : old_ip;
+ MemMove(op_base + op, from, 64);
+ op += len;
+ }
+ } while (ip < ip_limit_min_slop && op < op_limit_min_slop);
+ exit:
+ ip--;
+ assert(ip <= ip_limit);
+ }
+ return {ip, op};
+}
+
+// Helper class for decompression
+class SnappyDecompressor {
+ private:
+ Source* reader_; // Underlying source of bytes to decompress
+ const char* ip_; // Points to next buffered byte
+ const char* ip_limit_; // Points just past buffered bytes
+ // If ip < ip_limit_min_maxtaglen_ it's safe to read kMaxTagLength from
+ // buffer.
+ const char* ip_limit_min_maxtaglen_;
+ uint32_t peeked_; // Bytes peeked from reader (need to skip)
+ bool eof_; // Hit end of input without an error?
+ char scratch_[kMaximumTagLength]; // See RefillTag().
+
+ // Ensure that all of the tag metadata for the next tag is available
+ // in [ip_..ip_limit_-1]. Also ensures that [ip,ip+4] is readable even
+ // if (ip_limit_ - ip_ < 5).
+ //
+ // Returns true on success, false on error or end of input.
+ bool RefillTag();
+
+ void ResetLimit(const char* ip) {
+ ip_limit_min_maxtaglen_ =
+ ip_limit_ - std::min<ptrdiff_t>(ip_limit_ - ip, kMaximumTagLength - 1);
+ }
+
+ public:
+ explicit SnappyDecompressor(Source* reader)
+ : reader_(reader), ip_(NULL), ip_limit_(NULL), peeked_(0), eof_(false) {}
+
+ ~SnappyDecompressor() {
+ // Advance past any bytes we peeked at from the reader
+ reader_->Skip(peeked_);
+ }
+
+ // Returns true iff we have hit the end of the input without an error.
+ bool eof() const { return eof_; }
+
+ // Read the uncompressed length stored at the start of the compressed data.
+ // On success, stores the length in *result and returns true.
+ // On failure, returns false.
+ bool ReadUncompressedLength(uint32_t* result) {
+ assert(ip_ == NULL); // Must not have read anything yet
+ // Length is encoded in 1..5 bytes
+ *result = 0;
+ uint32_t shift = 0;
+ while (true) {
+ if (shift >= 32) return false;
+ size_t n;
+ const char* ip = reader_->Peek(&n);
+ if (n == 0) return false;
+ const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip));
+ reader_->Skip(1);
+ uint32_t val = c & 0x7f;
+ if (LeftShiftOverflows(static_cast<uint8_t>(val), shift)) return false;
+ *result |= val << shift;
+ if (c < 128) {
+ break;
+ }
+ shift += 7;
+ }
+ return true;
+ }
+
+ // Process the next item found in the input.
+ // Returns true if successful, false on error or end of input.
+ template <class Writer>
+#if defined(__GNUC__) && defined(__x86_64__)
+ __attribute__((aligned(32)))
+#endif
+ void
+ DecompressAllTags(Writer* writer) {
+ const char* ip = ip_;
+ ResetLimit(ip);
+ auto op = writer->GetOutputPtr();
+ // We could have put this refill fragment only at the beginning of the loop.
+ // However, duplicating it at the end of each branch gives the compiler more
+ // scope to optimize the <ip_limit_ - ip> expression based on the local
+ // context, which overall increases speed.
+#define MAYBE_REFILL() \
+ if (SNAPPY_PREDICT_FALSE(ip >= ip_limit_min_maxtaglen_)) { \
+ ip_ = ip; \
+ if (SNAPPY_PREDICT_FALSE(!RefillTag())) goto exit; \
+ ip = ip_; \
+ ResetLimit(ip); \
+ } \
+ preload = static_cast<uint8_t>(*ip)
+
+ // At the start of the for loop below the least significant byte of preload
+ // contains the tag.
+ uint32_t preload;
+ MAYBE_REFILL();
+ for (;;) {
+ {
+ ptrdiff_t op_limit_min_slop;
+ auto op_base = writer->GetBase(&op_limit_min_slop);
+ if (op_base) {
+ auto res =
+ DecompressBranchless(reinterpret_cast<const uint8_t*>(ip),
+ reinterpret_cast<const uint8_t*>(ip_limit_),
+ op - op_base, op_base, op_limit_min_slop);
+ ip = reinterpret_cast<const char*>(res.first);
+ op = op_base + res.second;
+ MAYBE_REFILL();
+ }
+ }
+ const uint8_t c = static_cast<uint8_t>(preload);
+ ip++;
+
+ // Ratio of iterations that have LITERAL vs non-LITERAL for different
+ // inputs.
+ //
+ // input LITERAL NON_LITERAL
+ // -----------------------------------
+ // html|html4|cp 23% 77%
+ // urls 36% 64%
+ // jpg 47% 53%
+ // pdf 19% 81%
+ // txt[1-4] 25% 75%
+ // pb 24% 76%
+ // bin 24% 76%
+ if (SNAPPY_PREDICT_FALSE((c & 0x3) == LITERAL)) {
+ size_t literal_length = (c >> 2) + 1u;
+ if (writer->TryFastAppend(ip, ip_limit_ - ip, literal_length, &op)) {
+ assert(literal_length < 61);
+ ip += literal_length;
+ // NOTE: There is no MAYBE_REFILL() here, as TryFastAppend()
+ // will not return true unless there's already at least five spare
+ // bytes in addition to the literal.
+ preload = static_cast<uint8_t>(*ip);
+ continue;
+ }
+ if (SNAPPY_PREDICT_FALSE(literal_length >= 61)) {
+ // Long literal.
+ const size_t literal_length_length = literal_length - 60;
+ literal_length =
+ ExtractLowBytes(LittleEndian::Load32(ip), literal_length_length) +
+ 1;
+ ip += literal_length_length;
+ }
+
+ size_t avail = ip_limit_ - ip;
+ while (avail < literal_length) {
+ if (!writer->Append(ip, avail, &op)) goto exit;
+ literal_length -= avail;
+ reader_->Skip(peeked_);
+ size_t n;
+ ip = reader_->Peek(&n);
+ avail = n;
+ peeked_ = avail;
+ if (avail == 0) goto exit;
+ ip_limit_ = ip + avail;
+ ResetLimit(ip);
+ }
+ if (!writer->Append(ip, literal_length, &op)) goto exit;
+ ip += literal_length;
+ MAYBE_REFILL();
+ } else {
+ if (SNAPPY_PREDICT_FALSE((c & 3) == COPY_4_BYTE_OFFSET)) {
+ const size_t copy_offset = LittleEndian::Load32(ip);
+ const size_t length = (c >> 2) + 1;
+ ip += 4;
+
+ if (!writer->AppendFromSelf(copy_offset, length, &op)) goto exit;
+ } else {
+ const ptrdiff_t entry = table.length_minus_offset[c];
+ preload = LittleEndian::Load32(ip);
+ const uint32_t trailer = ExtractLowBytes(preload, c & 3);
+ const uint32_t length = entry & 0xff;
+ assert(length > 0);
+
+ // copy_offset/256 is encoded in bits 8..10. By just fetching
+ // those bits, we get copy_offset (since the bit-field starts at
+ // bit 8).
+ const uint32_t copy_offset = trailer - entry + length;
+ if (!writer->AppendFromSelf(copy_offset, length, &op)) goto exit;
+
+ ip += (c & 3);
+ // By using the result of the previous load we reduce the critical
+ // dependency chain of ip to 4 cycles.
+ preload >>= (c & 3) * 8;
+ if (ip < ip_limit_min_maxtaglen_) continue;
+ }
+ MAYBE_REFILL();
+ }
+ }
+#undef MAYBE_REFILL
+ exit:
+ writer->SetOutputPtr(op);
+ }
+};
+
+constexpr uint32_t CalculateNeeded(uint8_t tag) {
+ return ((tag & 3) == 0 && tag >= (60 * 4))
+ ? (tag >> 2) - 58
+ : (0x05030201 >> ((tag * 8) & 31)) & 0xFF;
+}
+
+#if __cplusplus >= 201402L
+constexpr bool VerifyCalculateNeeded() {
+ for (int i = 0; i < 1; i++) {
+ if (CalculateNeeded(i) != (char_table[i] >> 11) + 1) return false;
+ }
+ return true;
+}
+
+// Make sure CalculateNeeded is correct by verifying it against the established
+// table encoding the number of added bytes needed.
+static_assert(VerifyCalculateNeeded(), "");
+#endif // c++14
+
+bool SnappyDecompressor::RefillTag() {
+ const char* ip = ip_;
+ if (ip == ip_limit_) {
+ // Fetch a new fragment from the reader
+ reader_->Skip(peeked_); // All peeked bytes are used up
+ size_t n;
+ ip = reader_->Peek(&n);
+ peeked_ = n;
+ eof_ = (n == 0);
+ if (eof_) return false;
+ ip_limit_ = ip + n;
+ }
+
+ // Read the tag character
+ assert(ip < ip_limit_);
+ const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip));
+ // At this point make sure that the data for the next tag is consecutive.
+ // For copy 1 this means the next 2 bytes (tag and 1 byte offset)
+ // For copy 2 the next 3 bytes (tag and 2 byte offset)
+ // For copy 4 the next 5 bytes (tag and 4 byte offset)
+ // For all small literals we only need 1 byte buf for literals 60...63 the
+ // length is encoded in 1...4 extra bytes.
+ const uint32_t needed = CalculateNeeded(c);
+ assert(needed <= sizeof(scratch_));
+
+ // Read more bytes from reader if needed
+ uint32_t nbuf = ip_limit_ - ip;
+ if (nbuf < needed) {
+ // Stitch together bytes from ip and reader to form the word
+ // contents. We store the needed bytes in "scratch_". They
+ // will be consumed immediately by the caller since we do not
+ // read more than we need.
+ std::memmove(scratch_, ip, nbuf);
+ reader_->Skip(peeked_); // All peeked bytes are used up
+ peeked_ = 0;
+ while (nbuf < needed) {
+ size_t length;
+ const char* src = reader_->Peek(&length);
+ if (length == 0) return false;
+ uint32_t to_add = std::min<uint32_t>(needed - nbuf, length);
+ std::memcpy(scratch_ + nbuf, src, to_add);
+ nbuf += to_add;
+ reader_->Skip(to_add);
+ }
+ assert(nbuf == needed);
+ ip_ = scratch_;
+ ip_limit_ = scratch_ + needed;
+ } else if (nbuf < kMaximumTagLength) {
+ // Have enough bytes, but move into scratch_ so that we do not
+ // read past end of input
+ std::memmove(scratch_, ip, nbuf);
+ reader_->Skip(peeked_); // All peeked bytes are used up
+ peeked_ = 0;
+ ip_ = scratch_;
+ ip_limit_ = scratch_ + nbuf;
+ } else {
+ // Pass pointer to buffer returned by reader_.
+ ip_ = ip;
+ }
+ return true;
+}
+
+template <typename Writer>
+static bool InternalUncompress(Source* r, Writer* writer) {
+ // Read the uncompressed length from the front of the compressed input
+ SnappyDecompressor decompressor(r);
+ uint32_t uncompressed_len = 0;
+ if (!decompressor.ReadUncompressedLength(&uncompressed_len)) return false;
+
+ return InternalUncompressAllTags(&decompressor, writer, r->Available(),
+ uncompressed_len);
+}
+
+template <typename Writer>
+static bool InternalUncompressAllTags(SnappyDecompressor* decompressor,
+ Writer* writer, uint32_t compressed_len,
+ uint32_t uncompressed_len) {
+ Report("snappy_uncompress", compressed_len, uncompressed_len);
+
+ writer->SetExpectedLength(uncompressed_len);
+
+ // Process the entire input
+ decompressor->DecompressAllTags(writer);
+ writer->Flush();
+ return (decompressor->eof() && writer->CheckLength());
+}
+
+bool GetUncompressedLength(Source* source, uint32_t* result) {
+ SnappyDecompressor decompressor(source);
+ return decompressor.ReadUncompressedLength(result);
+}
+
+size_t Compress(Source* reader, Sink* writer) {
+ size_t written = 0;
+ size_t N = reader->Available();
+ const size_t uncompressed_size = N;
+ char ulength[Varint::kMax32];
+ char* p = Varint::Encode32(ulength, N);
+ writer->Append(ulength, p - ulength);
+ written += (p - ulength);
+
+ internal::WorkingMemory wmem(N);
+
+ while (N > 0) {
+ // Get next block to compress (without copying if possible)
+ size_t fragment_size;
+ const char* fragment = reader->Peek(&fragment_size);
+ assert(fragment_size != 0); // premature end of input
+ const size_t num_to_read = std::min(N, kBlockSize);
+ size_t bytes_read = fragment_size;
+
+ size_t pending_advance = 0;
+ if (bytes_read >= num_to_read) {
+ // Buffer returned by reader is large enough
+ pending_advance = num_to_read;
+ fragment_size = num_to_read;
+ } else {
+ char* scratch = wmem.GetScratchInput();
+ std::memcpy(scratch, fragment, bytes_read);
+ reader->Skip(bytes_read);
+
+ while (bytes_read < num_to_read) {
+ fragment = reader->Peek(&fragment_size);
+ size_t n = std::min<size_t>(fragment_size, num_to_read - bytes_read);
+ std::memcpy(scratch + bytes_read, fragment, n);
+ bytes_read += n;
+ reader->Skip(n);
+ }
+ assert(bytes_read == num_to_read);
+ fragment = scratch;
+ fragment_size = num_to_read;
+ }
+ assert(fragment_size == num_to_read);
+
+ // Get encoding table for compression
+ int table_size;
+ uint16_t* table = wmem.GetHashTable(num_to_read, &table_size);
+
+ // Compress input_fragment and append to dest
+ const int max_output = MaxCompressedLength(num_to_read);
+
+ // Need a scratch buffer for the output, in case the byte sink doesn't
+ // have room for us directly.
+
+ // Since we encode kBlockSize regions followed by a region
+ // which is <= kBlockSize in length, a previously allocated
+ // scratch_output[] region is big enough for this iteration.
+ char* dest = writer->GetAppendBuffer(max_output, wmem.GetScratchOutput());
+ char* end = internal::CompressFragment(fragment, fragment_size, dest, table,
+ table_size);
+ writer->Append(dest, end - dest);
+ written += (end - dest);
+
+ N -= num_to_read;
+ reader->Skip(pending_advance);
+ }
+
+ Report("snappy_compress", written, uncompressed_size);
+
+ return written;
+}
+
+// -----------------------------------------------------------------------
+// IOVec interfaces
+// -----------------------------------------------------------------------
+
+// A type that writes to an iovec.
+// Note that this is not a "ByteSink", but a type that matches the
+// Writer template argument to SnappyDecompressor::DecompressAllTags().
+class SnappyIOVecWriter {
+ private:
+ // output_iov_end_ is set to iov + count and used to determine when
+ // the end of the iovs is reached.
+ const struct iovec* output_iov_end_;
+
+#if !defined(NDEBUG)
+ const struct iovec* output_iov_;
+#endif // !defined(NDEBUG)
+
+ // Current iov that is being written into.
+ const struct iovec* curr_iov_;
+
+ // Pointer to current iov's write location.
+ char* curr_iov_output_;
+
+ // Remaining bytes to write into curr_iov_output.
+ size_t curr_iov_remaining_;
+
+ // Total bytes decompressed into output_iov_ so far.
+ size_t total_written_;
+
+ // Maximum number of bytes that will be decompressed into output_iov_.
+ size_t output_limit_;
+
+ static inline char* GetIOVecPointer(const struct iovec* iov, size_t offset) {
+ return reinterpret_cast<char*>(iov->iov_base) + offset;
+ }
+
+ public:
+ // Does not take ownership of iov. iov must be valid during the
+ // entire lifetime of the SnappyIOVecWriter.
+ inline SnappyIOVecWriter(const struct iovec* iov, size_t iov_count)
+ : output_iov_end_(iov + iov_count),
+#if !defined(NDEBUG)
+ output_iov_(iov),
+#endif // !defined(NDEBUG)
+ curr_iov_(iov),
+ curr_iov_output_(iov_count ? reinterpret_cast<char*>(iov->iov_base)
+ : nullptr),
+ curr_iov_remaining_(iov_count ? iov->iov_len : 0),
+ total_written_(0),
+ output_limit_(-1) {
+ }
+
+ inline void SetExpectedLength(size_t len) { output_limit_ = len; }
+
+ inline bool CheckLength() const { return total_written_ == output_limit_; }
+
+ inline bool Append(const char* ip, size_t len, char**) {
+ if (total_written_ + len > output_limit_) {
+ return false;
+ }
+
+ return AppendNoCheck(ip, len);
+ }
+
+ char* GetOutputPtr() { return nullptr; }
+ char* GetBase(ptrdiff_t*) { return nullptr; }
+ void SetOutputPtr(char* op) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)op;
+ }
+
+ inline bool AppendNoCheck(const char* ip, size_t len) {
+ while (len > 0) {
+ if (curr_iov_remaining_ == 0) {
+ // This iovec is full. Go to the next one.
+ if (curr_iov_ + 1 >= output_iov_end_) {
+ return false;
+ }
+ ++curr_iov_;
+ curr_iov_output_ = reinterpret_cast<char*>(curr_iov_->iov_base);
+ curr_iov_remaining_ = curr_iov_->iov_len;
+ }
+
+ const size_t to_write = std::min(len, curr_iov_remaining_);
+ std::memcpy(curr_iov_output_, ip, to_write);
+ curr_iov_output_ += to_write;
+ curr_iov_remaining_ -= to_write;
+ total_written_ += to_write;
+ ip += to_write;
+ len -= to_write;
+ }
+
+ return true;
+ }
+
+ inline bool TryFastAppend(const char* ip, size_t available, size_t len,
+ char**) {
+ const size_t space_left = output_limit_ - total_written_;
+ if (len <= 16 && available >= 16 + kMaximumTagLength && space_left >= 16 &&
+ curr_iov_remaining_ >= 16) {
+ // Fast path, used for the majority (about 95%) of invocations.
+ UnalignedCopy128(ip, curr_iov_output_);
+ curr_iov_output_ += len;
+ curr_iov_remaining_ -= len;
+ total_written_ += len;
+ return true;
+ }
+
+ return false;
+ }
+
+ inline bool AppendFromSelf(size_t offset, size_t len, char**) {
+ // See SnappyArrayWriter::AppendFromSelf for an explanation of
+ // the "offset - 1u" trick.
+ if (offset - 1u >= total_written_) {
+ return false;
+ }
+ const size_t space_left = output_limit_ - total_written_;
+ if (len > space_left) {
+ return false;
+ }
+
+ // Locate the iovec from which we need to start the copy.
+ const iovec* from_iov = curr_iov_;
+ size_t from_iov_offset = curr_iov_->iov_len - curr_iov_remaining_;
+ while (offset > 0) {
+ if (from_iov_offset >= offset) {
+ from_iov_offset -= offset;
+ break;
+ }
+
+ offset -= from_iov_offset;
+ --from_iov;
+#if !defined(NDEBUG)
+ assert(from_iov >= output_iov_);
+#endif // !defined(NDEBUG)
+ from_iov_offset = from_iov->iov_len;
+ }
+
+ // Copy <len> bytes starting from the iovec pointed to by from_iov_index to
+ // the current iovec.
+ while (len > 0) {
+ assert(from_iov <= curr_iov_);
+ if (from_iov != curr_iov_) {
+ const size_t to_copy =
+ std::min(from_iov->iov_len - from_iov_offset, len);
+ AppendNoCheck(GetIOVecPointer(from_iov, from_iov_offset), to_copy);
+ len -= to_copy;
+ if (len > 0) {
+ ++from_iov;
+ from_iov_offset = 0;
+ }
+ } else {
+ size_t to_copy = curr_iov_remaining_;
+ if (to_copy == 0) {
+ // This iovec is full. Go to the next one.
+ if (curr_iov_ + 1 >= output_iov_end_) {
+ return false;
+ }
+ ++curr_iov_;
+ curr_iov_output_ = reinterpret_cast<char*>(curr_iov_->iov_base);
+ curr_iov_remaining_ = curr_iov_->iov_len;
+ continue;
+ }
+ if (to_copy > len) {
+ to_copy = len;
+ }
+ assert(to_copy > 0);
+
+ IncrementalCopy(GetIOVecPointer(from_iov, from_iov_offset),
+ curr_iov_output_, curr_iov_output_ + to_copy,
+ curr_iov_output_ + curr_iov_remaining_);
+ curr_iov_output_ += to_copy;
+ curr_iov_remaining_ -= to_copy;
+ from_iov_offset += to_copy;
+ total_written_ += to_copy;
+ len -= to_copy;
+ }
+ }
+
+ return true;
+ }
+
+ inline void Flush() {}
+};
+
+bool RawUncompressToIOVec(const char* compressed, size_t compressed_length,
+ const struct iovec* iov, size_t iov_cnt) {
+ ByteArraySource reader(compressed, compressed_length);
+ return RawUncompressToIOVec(&reader, iov, iov_cnt);
+}
+
+bool RawUncompressToIOVec(Source* compressed, const struct iovec* iov,
+ size_t iov_cnt) {
+ SnappyIOVecWriter output(iov, iov_cnt);
+ return InternalUncompress(compressed, &output);
+}
+
+// -----------------------------------------------------------------------
+// Flat array interfaces
+// -----------------------------------------------------------------------
+
+// A type that writes to a flat array.
+// Note that this is not a "ByteSink", but a type that matches the
+// Writer template argument to SnappyDecompressor::DecompressAllTags().
+class SnappyArrayWriter {
+ private:
+ char* base_;
+ char* op_;
+ char* op_limit_;
+ // If op < op_limit_min_slop_ then it's safe to unconditionally write
+ // kSlopBytes starting at op.
+ char* op_limit_min_slop_;
+
+ public:
+ inline explicit SnappyArrayWriter(char* dst)
+ : base_(dst),
+ op_(dst),
+ op_limit_(dst),
+ op_limit_min_slop_(dst) {} // Safe default see invariant.
+
+ inline void SetExpectedLength(size_t len) {
+ op_limit_ = op_ + len;
+ // Prevent pointer from being past the buffer.
+ op_limit_min_slop_ = op_limit_ - std::min<size_t>(kSlopBytes - 1, len);
+ }
+
+ inline bool CheckLength() const { return op_ == op_limit_; }
+
+ char* GetOutputPtr() { return op_; }
+ char* GetBase(ptrdiff_t* op_limit_min_slop) {
+ *op_limit_min_slop = op_limit_min_slop_ - base_;
+ return base_;
+ }
+ void SetOutputPtr(char* op) { op_ = op; }
+
+ inline bool Append(const char* ip, size_t len, char** op_p) {
+ char* op = *op_p;
+ const size_t space_left = op_limit_ - op;
+ if (space_left < len) return false;
+ std::memcpy(op, ip, len);
+ *op_p = op + len;
+ return true;
+ }
+
+ inline bool TryFastAppend(const char* ip, size_t available, size_t len,
+ char** op_p) {
+ char* op = *op_p;
+ const size_t space_left = op_limit_ - op;
+ if (len <= 16 && available >= 16 + kMaximumTagLength && space_left >= 16) {
+ // Fast path, used for the majority (about 95%) of invocations.
+ UnalignedCopy128(ip, op);
+ *op_p = op + len;
+ return true;
+ } else {
+ return false;
+ }
+ }
+
+ SNAPPY_ATTRIBUTE_ALWAYS_INLINE
+ inline bool AppendFromSelf(size_t offset, size_t len, char** op_p) {
+ assert(len > 0);
+ char* const op = *op_p;
+ assert(op >= base_);
+ char* const op_end = op + len;
+
+ // Check if we try to append from before the start of the buffer.
+ if (SNAPPY_PREDICT_FALSE(static_cast<size_t>(op - base_) < offset))
+ return false;
+
+ if (SNAPPY_PREDICT_FALSE((kSlopBytes < 64 && len > kSlopBytes) ||
+ op >= op_limit_min_slop_ || offset < len)) {
+ if (op_end > op_limit_ || offset == 0) return false;
+ *op_p = IncrementalCopy(op - offset, op, op_end, op_limit_);
+ return true;
+ }
+ std::memmove(op, op - offset, kSlopBytes);
+ *op_p = op_end;
+ return true;
+ }
+ inline size_t Produced() const {
+ assert(op_ >= base_);
+ return op_ - base_;
+ }
+ inline void Flush() {}
+};
+
+bool RawUncompress(const char* compressed, size_t compressed_length,
+ char* uncompressed) {
+ ByteArraySource reader(compressed, compressed_length);
+ return RawUncompress(&reader, uncompressed);
+}
+
+bool RawUncompress(Source* compressed, char* uncompressed) {
+ SnappyArrayWriter output(uncompressed);
+ return InternalUncompress(compressed, &output);
+}
+
+bool Uncompress(const char* compressed, size_t compressed_length,
+ std::string* uncompressed) {
+ size_t ulength;
+ if (!GetUncompressedLength(compressed, compressed_length, &ulength)) {
+ return false;
+ }
+ // On 32-bit builds: max_size() < kuint32max. Check for that instead
+ // of crashing (e.g., consider externally specified compressed data).
+ if (ulength > uncompressed->max_size()) {
+ return false;
+ }
+ STLStringResizeUninitialized(uncompressed, ulength);
+ return RawUncompress(compressed, compressed_length,
+ string_as_array(uncompressed));
+}
+
+// A Writer that drops everything on the floor and just does validation
+class SnappyDecompressionValidator {
+ private:
+ size_t expected_;
+ size_t produced_;
+
+ public:
+ inline SnappyDecompressionValidator() : expected_(0), produced_(0) {}
+ inline void SetExpectedLength(size_t len) { expected_ = len; }
+ size_t GetOutputPtr() { return produced_; }
+ size_t GetBase(ptrdiff_t* op_limit_min_slop) {
+ *op_limit_min_slop = std::numeric_limits<ptrdiff_t>::max() - kSlopBytes + 1;
+ return 1;
+ }
+ void SetOutputPtr(size_t op) { produced_ = op; }
+ inline bool CheckLength() const { return expected_ == produced_; }
+ inline bool Append(const char* ip, size_t len, size_t* produced) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)ip;
+
+ *produced += len;
+ return *produced <= expected_;
+ }
+ inline bool TryFastAppend(const char* ip, size_t available, size_t length,
+ size_t* produced) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)ip;
+ (void)available;
+ (void)length;
+ (void)produced;
+
+ return false;
+ }
+ inline bool AppendFromSelf(size_t offset, size_t len, size_t* produced) {
+ // See SnappyArrayWriter::AppendFromSelf for an explanation of
+ // the "offset - 1u" trick.
+ if (*produced <= offset - 1u) return false;
+ *produced += len;
+ return *produced <= expected_;
+ }
+ inline void Flush() {}
+};
+
+bool IsValidCompressedBuffer(const char* compressed, size_t compressed_length) {
+ ByteArraySource reader(compressed, compressed_length);
+ SnappyDecompressionValidator writer;
+ return InternalUncompress(&reader, &writer);
+}
+
+bool IsValidCompressed(Source* compressed) {
+ SnappyDecompressionValidator writer;
+ return InternalUncompress(compressed, &writer);
+}
+
+void RawCompress(const char* input, size_t input_length, char* compressed,
+ size_t* compressed_length) {
+ ByteArraySource reader(input, input_length);
+ UncheckedByteArraySink writer(compressed);
+ Compress(&reader, &writer);
+
+ // Compute how many bytes were added
+ *compressed_length = (writer.CurrentDestination() - compressed);
+}
+
+size_t Compress(const char* input, size_t input_length,
+ std::string* compressed) {
+ // Pre-grow the buffer to the max length of the compressed output
+ STLStringResizeUninitialized(compressed, MaxCompressedLength(input_length));
+
+ size_t compressed_length;
+ RawCompress(input, input_length, string_as_array(compressed),
+ &compressed_length);
+ compressed->resize(compressed_length);
+ return compressed_length;
+}
+
+// -----------------------------------------------------------------------
+// Sink interface
+// -----------------------------------------------------------------------
+
+// A type that decompresses into a Sink. The template parameter
+// Allocator must export one method "char* Allocate(int size);", which
+// allocates a buffer of "size" and appends that to the destination.
+template <typename Allocator>
+class SnappyScatteredWriter {
+ Allocator allocator_;
+
+ // We need random access into the data generated so far. Therefore
+ // we keep track of all of the generated data as an array of blocks.
+ // All of the blocks except the last have length kBlockSize.
+ std::vector<char*> blocks_;
+ size_t expected_;
+
+ // Total size of all fully generated blocks so far
+ size_t full_size_;
+
+ // Pointer into current output block
+ char* op_base_; // Base of output block
+ char* op_ptr_; // Pointer to next unfilled byte in block
+ char* op_limit_; // Pointer just past block
+ // If op < op_limit_min_slop_ then it's safe to unconditionally write
+ // kSlopBytes starting at op.
+ char* op_limit_min_slop_;
+
+ inline size_t Size() const { return full_size_ + (op_ptr_ - op_base_); }
+
+ bool SlowAppend(const char* ip, size_t len);
+ bool SlowAppendFromSelf(size_t offset, size_t len);
+
+ public:
+ inline explicit SnappyScatteredWriter(const Allocator& allocator)
+ : allocator_(allocator),
+ full_size_(0),
+ op_base_(NULL),
+ op_ptr_(NULL),
+ op_limit_(NULL),
+ op_limit_min_slop_(NULL) {}
+ char* GetOutputPtr() { return op_ptr_; }
+ char* GetBase(ptrdiff_t* op_limit_min_slop) {
+ *op_limit_min_slop = op_limit_min_slop_ - op_base_;
+ return op_base_;
+ }
+ void SetOutputPtr(char* op) { op_ptr_ = op; }
+
+ inline void SetExpectedLength(size_t len) {
+ assert(blocks_.empty());
+ expected_ = len;
+ }
+
+ inline bool CheckLength() const { return Size() == expected_; }
+
+ // Return the number of bytes actually uncompressed so far
+ inline size_t Produced() const { return Size(); }
+
+ inline bool Append(const char* ip, size_t len, char** op_p) {
+ char* op = *op_p;
+ size_t avail = op_limit_ - op;
+ if (len <= avail) {
+ // Fast path
+ std::memcpy(op, ip, len);
+ *op_p = op + len;
+ return true;
+ } else {
+ op_ptr_ = op;
+ bool res = SlowAppend(ip, len);
+ *op_p = op_ptr_;
+ return res;
+ }
+ }
+
+ inline bool TryFastAppend(const char* ip, size_t available, size_t length,
+ char** op_p) {
+ char* op = *op_p;
+ const int space_left = op_limit_ - op;
+ if (length <= 16 && available >= 16 + kMaximumTagLength &&
+ space_left >= 16) {
+ // Fast path, used for the majority (about 95%) of invocations.
+ UnalignedCopy128(ip, op);
+ *op_p = op + length;
+ return true;
+ } else {
+ return false;
+ }
+ }
+
+ inline bool AppendFromSelf(size_t offset, size_t len, char** op_p) {
+ char* op = *op_p;
+ assert(op >= op_base_);
+ // Check if we try to append from before the start of the buffer.
+ if (SNAPPY_PREDICT_FALSE((kSlopBytes < 64 && len > kSlopBytes) ||
+ static_cast<size_t>(op - op_base_) < offset ||
+ op >= op_limit_min_slop_ || offset < len)) {
+ if (offset == 0) return false;
+ if (SNAPPY_PREDICT_FALSE(static_cast<size_t>(op - op_base_) < offset ||
+ op + len > op_limit_)) {
+ op_ptr_ = op;
+ bool res = SlowAppendFromSelf(offset, len);
+ *op_p = op_ptr_;
+ return res;
+ }
+ *op_p = IncrementalCopy(op - offset, op, op + len, op_limit_);
+ return true;
+ }
+ // Fast path
+ char* const op_end = op + len;
+ std::memmove(op, op - offset, kSlopBytes);
+ *op_p = op_end;
+ return true;
+ }
+
+ // Called at the end of the decompress. We ask the allocator
+ // write all blocks to the sink.
+ inline void Flush() { allocator_.Flush(Produced()); }
+};
+
+template <typename Allocator>
+bool SnappyScatteredWriter<Allocator>::SlowAppend(const char* ip, size_t len) {
+ size_t avail = op_limit_ - op_ptr_;
+ while (len > avail) {
+ // Completely fill this block
+ std::memcpy(op_ptr_, ip, avail);
+ op_ptr_ += avail;
+ assert(op_limit_ - op_ptr_ == 0);
+ full_size_ += (op_ptr_ - op_base_);
+ len -= avail;
+ ip += avail;
+
+ // Bounds check
+ if (full_size_ + len > expected_) return false;
+
+ // Make new block
+ size_t bsize = std::min<size_t>(kBlockSize, expected_ - full_size_);
+ op_base_ = allocator_.Allocate(bsize);
+ op_ptr_ = op_base_;
+ op_limit_ = op_base_ + bsize;
+ op_limit_min_slop_ = op_limit_ - std::min<size_t>(kSlopBytes - 1, bsize);
+
+ blocks_.push_back(op_base_);
+ avail = bsize;
+ }
+
+ std::memcpy(op_ptr_, ip, len);
+ op_ptr_ += len;
+ return true;
+}
+
+template <typename Allocator>
+bool SnappyScatteredWriter<Allocator>::SlowAppendFromSelf(size_t offset,
+ size_t len) {
+ // Overflow check
+ // See SnappyArrayWriter::AppendFromSelf for an explanation of
+ // the "offset - 1u" trick.
+ const size_t cur = Size();
+ if (offset - 1u >= cur) return false;
+ if (expected_ - cur < len) return false;
+
+ // Currently we shouldn't ever hit this path because Compress() chops the
+ // input into blocks and does not create cross-block copies. However, it is
+ // nice if we do not rely on that, since we can get better compression if we
+ // allow cross-block copies and thus might want to change the compressor in
+ // the future.
+ // TODO Replace this with a properly optimized path. This is not
+ // triggered right now. But this is so super slow, that it would regress
+ // performance unacceptably if triggered.
+ size_t src = cur - offset;
+ char* op = op_ptr_;
+ while (len-- > 0) {
+ char c = blocks_[src >> kBlockLog][src & (kBlockSize - 1)];
+ if (!Append(&c, 1, &op)) {
+ op_ptr_ = op;
+ return false;
+ }
+ src++;
+ }
+ op_ptr_ = op;
+ return true;
+}
+
+class SnappySinkAllocator {
+ public:
+ explicit SnappySinkAllocator(Sink* dest) : dest_(dest) {}
+ ~SnappySinkAllocator() {}
+
+ char* Allocate(int size) {
+ Datablock block(new char[size], size);
+ blocks_.push_back(block);
+ return block.data;
+ }
+
+ // We flush only at the end, because the writer wants
+ // random access to the blocks and once we hand the
+ // block over to the sink, we can't access it anymore.
+ // Also we don't write more than has been actually written
+ // to the blocks.
+ void Flush(size_t size) {
+ size_t size_written = 0;
+ for (Datablock& block : blocks_) {
+ size_t block_size = std::min<size_t>(block.size, size - size_written);
+ dest_->AppendAndTakeOwnership(block.data, block_size,
+ &SnappySinkAllocator::Deleter, NULL);
+ size_written += block_size;
+ }
+ blocks_.clear();
+ }
+
+ private:
+ struct Datablock {
+ char* data;
+ size_t size;
+ Datablock(char* p, size_t s) : data(p), size(s) {}
+ };
+
+ static void Deleter(void* arg, const char* bytes, size_t size) {
+ // TODO: Switch to [[maybe_unused]] when we can assume C++17.
+ (void)arg;
+ (void)size;
+
+ delete[] bytes;
+ }
+
+ Sink* dest_;
+ std::vector<Datablock> blocks_;
+
+ // Note: copying this object is allowed
+};
+
+size_t UncompressAsMuchAsPossible(Source* compressed, Sink* uncompressed) {
+ SnappySinkAllocator allocator(uncompressed);
+ SnappyScatteredWriter<SnappySinkAllocator> writer(allocator);
+ InternalUncompress(compressed, &writer);
+ return writer.Produced();
+}
+
+bool Uncompress(Source* compressed, Sink* uncompressed) {
+ // Read the uncompressed length from the front of the compressed input
+ SnappyDecompressor decompressor(compressed);
+ uint32_t uncompressed_len = 0;
+ if (!decompressor.ReadUncompressedLength(&uncompressed_len)) {
+ return false;
+ }
+
+ char c;
+ size_t allocated_size;
+ char* buf = uncompressed->GetAppendBufferVariable(1, uncompressed_len, &c, 1,
+ &allocated_size);
+
+ const size_t compressed_len = compressed->Available();
+ // If we can get a flat buffer, then use it, otherwise do block by block
+ // uncompression
+ if (allocated_size >= uncompressed_len) {
+ SnappyArrayWriter writer(buf);
+ bool result = InternalUncompressAllTags(&decompressor, &writer,
+ compressed_len, uncompressed_len);
+ uncompressed->Append(buf, writer.Produced());
+ return result;
+ } else {
+ SnappySinkAllocator allocator(uncompressed);
+ SnappyScatteredWriter<SnappySinkAllocator> writer(allocator);
+ return InternalUncompressAllTags(&decompressor, &writer, compressed_len,
+ uncompressed_len);
+ }
+}
+
+} // namespace snappy
diff --git a/other-licenses/snappy/src/snappy.h b/other-licenses/snappy/src/snappy.h
new file mode 100644
index 0000000000..e4fdad3354
--- /dev/null
+++ b/other-licenses/snappy/src/snappy.h
@@ -0,0 +1,209 @@
+// Copyright 2005 and onwards Google Inc.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// A light-weight compression algorithm. It is designed for speed of
+// compression and decompression, rather than for the utmost in space
+// savings.
+//
+// For getting better compression ratios when you are compressing data
+// with long repeated sequences or compressing data that is similar to
+// other data, while still compressing fast, you might look at first
+// using BMDiff and then compressing the output of BMDiff with
+// Snappy.
+
+#ifndef THIRD_PARTY_SNAPPY_SNAPPY_H__
+#define THIRD_PARTY_SNAPPY_SNAPPY_H__
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <string>
+
+#include "snappy-stubs-public.h"
+
+namespace snappy {
+ class Source;
+ class Sink;
+
+ // ------------------------------------------------------------------------
+ // Generic compression/decompression routines.
+ // ------------------------------------------------------------------------
+
+ // Compress the bytes read from "*source" and append to "*sink". Return the
+ // number of bytes written.
+ size_t Compress(Source* source, Sink* sink);
+
+ // Find the uncompressed length of the given stream, as given by the header.
+ // Note that the true length could deviate from this; the stream could e.g.
+ // be truncated.
+ //
+ // Also note that this leaves "*source" in a state that is unsuitable for
+ // further operations, such as RawUncompress(). You will need to rewind
+ // or recreate the source yourself before attempting any further calls.
+ bool GetUncompressedLength(Source* source, uint32_t* result);
+
+ // ------------------------------------------------------------------------
+ // Higher-level string based routines (should be sufficient for most users)
+ // ------------------------------------------------------------------------
+
+ // Sets "*compressed" to the compressed version of "input[0,input_length-1]".
+ // Original contents of *compressed are lost.
+ //
+ // REQUIRES: "input[]" is not an alias of "*compressed".
+ size_t Compress(const char* input, size_t input_length,
+ std::string* compressed);
+
+ // Decompresses "compressed[0,compressed_length-1]" to "*uncompressed".
+ // Original contents of "*uncompressed" are lost.
+ //
+ // REQUIRES: "compressed[]" is not an alias of "*uncompressed".
+ //
+ // returns false if the message is corrupted and could not be decompressed
+ bool Uncompress(const char* compressed, size_t compressed_length,
+ std::string* uncompressed);
+
+ // Decompresses "compressed" to "*uncompressed".
+ //
+ // returns false if the message is corrupted and could not be decompressed
+ bool Uncompress(Source* compressed, Sink* uncompressed);
+
+ // This routine uncompresses as much of the "compressed" as possible
+ // into sink. It returns the number of valid bytes added to sink
+ // (extra invalid bytes may have been added due to errors; the caller
+ // should ignore those). The emitted data typically has length
+ // GetUncompressedLength(), but may be shorter if an error is
+ // encountered.
+ size_t UncompressAsMuchAsPossible(Source* compressed, Sink* uncompressed);
+
+ // ------------------------------------------------------------------------
+ // Lower-level character array based routines. May be useful for
+ // efficiency reasons in certain circumstances.
+ // ------------------------------------------------------------------------
+
+ // REQUIRES: "compressed" must point to an area of memory that is at
+ // least "MaxCompressedLength(input_length)" bytes in length.
+ //
+ // Takes the data stored in "input[0..input_length]" and stores
+ // it in the array pointed to by "compressed".
+ //
+ // "*compressed_length" is set to the length of the compressed output.
+ //
+ // Example:
+ // char* output = new char[snappy::MaxCompressedLength(input_length)];
+ // size_t output_length;
+ // RawCompress(input, input_length, output, &output_length);
+ // ... Process(output, output_length) ...
+ // delete [] output;
+ void RawCompress(const char* input,
+ size_t input_length,
+ char* compressed,
+ size_t* compressed_length);
+
+ // Given data in "compressed[0..compressed_length-1]" generated by
+ // calling the Snappy::Compress routine, this routine
+ // stores the uncompressed data to
+ // uncompressed[0..GetUncompressedLength(compressed)-1]
+ // returns false if the message is corrupted and could not be decrypted
+ bool RawUncompress(const char* compressed, size_t compressed_length,
+ char* uncompressed);
+
+ // Given data from the byte source 'compressed' generated by calling
+ // the Snappy::Compress routine, this routine stores the uncompressed
+ // data to
+ // uncompressed[0..GetUncompressedLength(compressed,compressed_length)-1]
+ // returns false if the message is corrupted and could not be decrypted
+ bool RawUncompress(Source* compressed, char* uncompressed);
+
+ // Given data in "compressed[0..compressed_length-1]" generated by
+ // calling the Snappy::Compress routine, this routine
+ // stores the uncompressed data to the iovec "iov". The number of physical
+ // buffers in "iov" is given by iov_cnt and their cumulative size
+ // must be at least GetUncompressedLength(compressed). The individual buffers
+ // in "iov" must not overlap with each other.
+ //
+ // returns false if the message is corrupted and could not be decrypted
+ bool RawUncompressToIOVec(const char* compressed, size_t compressed_length,
+ const struct iovec* iov, size_t iov_cnt);
+
+ // Given data from the byte source 'compressed' generated by calling
+ // the Snappy::Compress routine, this routine stores the uncompressed
+ // data to the iovec "iov". The number of physical
+ // buffers in "iov" is given by iov_cnt and their cumulative size
+ // must be at least GetUncompressedLength(compressed). The individual buffers
+ // in "iov" must not overlap with each other.
+ //
+ // returns false if the message is corrupted and could not be decrypted
+ bool RawUncompressToIOVec(Source* compressed, const struct iovec* iov,
+ size_t iov_cnt);
+
+ // Returns the maximal size of the compressed representation of
+ // input data that is "source_bytes" bytes in length;
+ size_t MaxCompressedLength(size_t source_bytes);
+
+ // REQUIRES: "compressed[]" was produced by RawCompress() or Compress()
+ // Returns true and stores the length of the uncompressed data in
+ // *result normally. Returns false on parsing error.
+ // This operation takes O(1) time.
+ bool GetUncompressedLength(const char* compressed, size_t compressed_length,
+ size_t* result);
+
+ // Returns true iff the contents of "compressed[]" can be uncompressed
+ // successfully. Does not return the uncompressed data. Takes
+ // time proportional to compressed_length, but is usually at least
+ // a factor of four faster than actual decompression.
+ bool IsValidCompressedBuffer(const char* compressed,
+ size_t compressed_length);
+
+ // Returns true iff the contents of "compressed" can be uncompressed
+ // successfully. Does not return the uncompressed data. Takes
+ // time proportional to *compressed length, but is usually at least
+ // a factor of four faster than actual decompression.
+ // On success, consumes all of *compressed. On failure, consumes an
+ // unspecified prefix of *compressed.
+ bool IsValidCompressed(Source* compressed);
+
+ // The size of a compression block. Note that many parts of the compression
+ // code assumes that kBlockSize <= 65536; in particular, the hash table
+ // can only store 16-bit offsets, and EmitCopy() also assumes the offset
+ // is 65535 bytes or less. Note also that if you change this, it will
+ // affect the framing format (see framing_format.txt).
+ //
+ // Note that there might be older data around that is compressed with larger
+ // block sizes, so the decompression code should not rely on the
+ // non-existence of long backreferences.
+ static constexpr int kBlockLog = 16;
+ static constexpr size_t kBlockSize = 1 << kBlockLog;
+
+ static constexpr int kMinHashTableBits = 8;
+ static constexpr size_t kMinHashTableSize = 1 << kMinHashTableBits;
+
+ static constexpr int kMaxHashTableBits = 14;
+ static constexpr size_t kMaxHashTableSize = 1 << kMaxHashTableBits;
+} // end namespace snappy
+
+#endif // THIRD_PARTY_SNAPPY_SNAPPY_H__
diff --git a/other-licenses/snappy/src/snappy_compress_fuzzer.cc b/other-licenses/snappy/src/snappy_compress_fuzzer.cc
new file mode 100644
index 0000000000..1d4429a8c1
--- /dev/null
+++ b/other-licenses/snappy/src/snappy_compress_fuzzer.cc
@@ -0,0 +1,60 @@
+// Copyright 2019 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// libFuzzer harness for fuzzing snappy compression code.
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <cassert>
+#include <string>
+
+#include "snappy.h"
+
+// Entry point for LibFuzzer.
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+ std::string input(reinterpret_cast<const char*>(data), size);
+
+ std::string compressed;
+ size_t compressed_size =
+ snappy::Compress(input.data(), input.size(), &compressed);
+
+ (void)compressed_size; // Variable only used in debug builds.
+ assert(compressed_size == compressed.size());
+ assert(compressed.size() <= snappy::MaxCompressedLength(input.size()));
+ assert(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+
+ std::string uncompressed_after_compress;
+ bool uncompress_succeeded = snappy::Uncompress(
+ compressed.data(), compressed.size(), &uncompressed_after_compress);
+
+ (void)uncompress_succeeded; // Variable only used in debug builds.
+ assert(uncompress_succeeded);
+ assert(input == uncompressed_after_compress);
+ return 0;
+}
diff --git a/other-licenses/snappy/src/snappy_uncompress_fuzzer.cc b/other-licenses/snappy/src/snappy_uncompress_fuzzer.cc
new file mode 100644
index 0000000000..385bfb5a33
--- /dev/null
+++ b/other-licenses/snappy/src/snappy_uncompress_fuzzer.cc
@@ -0,0 +1,58 @@
+// Copyright 2019 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// libFuzzer harness for fuzzing snappy's decompression code.
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <cassert>
+#include <string>
+
+#include "snappy.h"
+
+// Entry point for LibFuzzer.
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+ std::string input(reinterpret_cast<const char*>(data), size);
+
+ // Avoid self-crafted decompression bombs.
+ size_t uncompressed_size;
+ constexpr size_t kMaxUncompressedSize = 1 << 20;
+ bool get_uncompressed_length_succeeded = snappy::GetUncompressedLength(
+ input.data(), input.size(), &uncompressed_size);
+ if (!get_uncompressed_length_succeeded ||
+ (uncompressed_size > kMaxUncompressedSize)) {
+ return 0;
+ }
+
+ std::string uncompressed;
+ // The return value of snappy::Uncompress() is ignored because decompression
+ // will fail on invalid inputs.
+ snappy::Uncompress(input.data(), input.size(), &uncompressed);
+ return 0;
+}
diff --git a/other-licenses/snappy/src/snappy_unittest.cc b/other-licenses/snappy/src/snappy_unittest.cc
new file mode 100644
index 0000000000..7a85635d73
--- /dev/null
+++ b/other-licenses/snappy/src/snappy_unittest.cc
@@ -0,0 +1,966 @@
+// Copyright 2005 and onwards Google Inc.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <algorithm>
+#include <cmath>
+#include <cstdlib>
+#include <random>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "snappy-test.h"
+
+#include "gtest/gtest.h"
+
+#include "snappy-internal.h"
+#include "snappy-sinksource.h"
+#include "snappy.h"
+#include "snappy_test_data.h"
+
+SNAPPY_FLAG(bool, snappy_dump_decompression_table, false,
+ "If true, we print the decompression table during tests.");
+
+namespace snappy {
+
+namespace {
+
+#if defined(HAVE_FUNC_MMAP) && defined(HAVE_FUNC_SYSCONF)
+
+// To test against code that reads beyond its input, this class copies a
+// string to a newly allocated group of pages, the last of which
+// is made unreadable via mprotect. Note that we need to allocate the
+// memory with mmap(), as POSIX allows mprotect() only on memory allocated
+// with mmap(), and some malloc/posix_memalign implementations expect to
+// be able to read previously allocated memory while doing heap allocations.
+class DataEndingAtUnreadablePage {
+ public:
+ explicit DataEndingAtUnreadablePage(const std::string& s) {
+ const size_t page_size = sysconf(_SC_PAGESIZE);
+ const size_t size = s.size();
+ // Round up space for string to a multiple of page_size.
+ size_t space_for_string = (size + page_size - 1) & ~(page_size - 1);
+ alloc_size_ = space_for_string + page_size;
+ mem_ = mmap(NULL, alloc_size_,
+ PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ CHECK_NE(MAP_FAILED, mem_);
+ protected_page_ = reinterpret_cast<char*>(mem_) + space_for_string;
+ char* dst = protected_page_ - size;
+ std::memcpy(dst, s.data(), size);
+ data_ = dst;
+ size_ = size;
+ // Make guard page unreadable.
+ CHECK_EQ(0, mprotect(protected_page_, page_size, PROT_NONE));
+ }
+
+ ~DataEndingAtUnreadablePage() {
+ const size_t page_size = sysconf(_SC_PAGESIZE);
+ // Undo the mprotect.
+ CHECK_EQ(0, mprotect(protected_page_, page_size, PROT_READ|PROT_WRITE));
+ CHECK_EQ(0, munmap(mem_, alloc_size_));
+ }
+
+ const char* data() const { return data_; }
+ size_t size() const { return size_; }
+
+ private:
+ size_t alloc_size_;
+ void* mem_;
+ char* protected_page_;
+ const char* data_;
+ size_t size_;
+};
+
+#else // defined(HAVE_FUNC_MMAP) && defined(HAVE_FUNC_SYSCONF)
+
+// Fallback for systems without mmap.
+using DataEndingAtUnreadablePage = std::string;
+
+#endif
+
+int VerifyString(const std::string& input) {
+ std::string compressed;
+ DataEndingAtUnreadablePage i(input);
+ const size_t written = snappy::Compress(i.data(), i.size(), &compressed);
+ CHECK_EQ(written, compressed.size());
+ CHECK_LE(compressed.size(),
+ snappy::MaxCompressedLength(input.size()));
+ CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+
+ std::string uncompressed;
+ DataEndingAtUnreadablePage c(compressed);
+ CHECK(snappy::Uncompress(c.data(), c.size(), &uncompressed));
+ CHECK_EQ(uncompressed, input);
+ return uncompressed.size();
+}
+
+void VerifyStringSink(const std::string& input) {
+ std::string compressed;
+ DataEndingAtUnreadablePage i(input);
+ const size_t written = snappy::Compress(i.data(), i.size(), &compressed);
+ CHECK_EQ(written, compressed.size());
+ CHECK_LE(compressed.size(),
+ snappy::MaxCompressedLength(input.size()));
+ CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+
+ std::string uncompressed;
+ uncompressed.resize(input.size());
+ snappy::UncheckedByteArraySink sink(string_as_array(&uncompressed));
+ DataEndingAtUnreadablePage c(compressed);
+ snappy::ByteArraySource source(c.data(), c.size());
+ CHECK(snappy::Uncompress(&source, &sink));
+ CHECK_EQ(uncompressed, input);
+}
+
+void VerifyIOVec(const std::string& input) {
+ std::string compressed;
+ DataEndingAtUnreadablePage i(input);
+ const size_t written = snappy::Compress(i.data(), i.size(), &compressed);
+ CHECK_EQ(written, compressed.size());
+ CHECK_LE(compressed.size(),
+ snappy::MaxCompressedLength(input.size()));
+ CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+
+ // Try uncompressing into an iovec containing a random number of entries
+ // ranging from 1 to 10.
+ char* buf = new char[input.size()];
+ std::minstd_rand0 rng(input.size());
+ std::uniform_int_distribution<size_t> uniform_1_to_10(1, 10);
+ size_t num = uniform_1_to_10(rng);
+ if (input.size() < num) {
+ num = input.size();
+ }
+ struct iovec* iov = new iovec[num];
+ size_t used_so_far = 0;
+ std::bernoulli_distribution one_in_five(1.0 / 5);
+ for (size_t i = 0; i < num; ++i) {
+ assert(used_so_far < input.size());
+ iov[i].iov_base = buf + used_so_far;
+ if (i == num - 1) {
+ iov[i].iov_len = input.size() - used_so_far;
+ } else {
+ // Randomly choose to insert a 0 byte entry.
+ if (one_in_five(rng)) {
+ iov[i].iov_len = 0;
+ } else {
+ std::uniform_int_distribution<size_t> uniform_not_used_so_far(
+ 0, input.size() - used_so_far - 1);
+ iov[i].iov_len = uniform_not_used_so_far(rng);
+ }
+ }
+ used_so_far += iov[i].iov_len;
+ }
+ CHECK(snappy::RawUncompressToIOVec(
+ compressed.data(), compressed.size(), iov, num));
+ CHECK(!memcmp(buf, input.data(), input.size()));
+ delete[] iov;
+ delete[] buf;
+}
+
+// Test that data compressed by a compressor that does not
+// obey block sizes is uncompressed properly.
+void VerifyNonBlockedCompression(const std::string& input) {
+ if (input.length() > snappy::kBlockSize) {
+ // We cannot test larger blocks than the maximum block size, obviously.
+ return;
+ }
+
+ std::string prefix;
+ Varint::Append32(&prefix, input.size());
+
+ // Setup compression table
+ snappy::internal::WorkingMemory wmem(input.size());
+ int table_size;
+ uint16_t* table = wmem.GetHashTable(input.size(), &table_size);
+
+ // Compress entire input in one shot
+ std::string compressed;
+ compressed += prefix;
+ compressed.resize(prefix.size()+snappy::MaxCompressedLength(input.size()));
+ char* dest = string_as_array(&compressed) + prefix.size();
+ char* end = snappy::internal::CompressFragment(input.data(), input.size(),
+ dest, table, table_size);
+ compressed.resize(end - compressed.data());
+
+ // Uncompress into std::string
+ std::string uncomp_str;
+ CHECK(snappy::Uncompress(compressed.data(), compressed.size(), &uncomp_str));
+ CHECK_EQ(uncomp_str, input);
+
+ // Uncompress using source/sink
+ std::string uncomp_str2;
+ uncomp_str2.resize(input.size());
+ snappy::UncheckedByteArraySink sink(string_as_array(&uncomp_str2));
+ snappy::ByteArraySource source(compressed.data(), compressed.size());
+ CHECK(snappy::Uncompress(&source, &sink));
+ CHECK_EQ(uncomp_str2, input);
+
+ // Uncompress into iovec
+ {
+ static const int kNumBlocks = 10;
+ struct iovec vec[kNumBlocks];
+ const int block_size = 1 + input.size() / kNumBlocks;
+ std::string iovec_data(block_size * kNumBlocks, 'x');
+ for (int i = 0; i < kNumBlocks; ++i) {
+ vec[i].iov_base = string_as_array(&iovec_data) + i * block_size;
+ vec[i].iov_len = block_size;
+ }
+ CHECK(snappy::RawUncompressToIOVec(compressed.data(), compressed.size(),
+ vec, kNumBlocks));
+ CHECK_EQ(std::string(iovec_data.data(), input.size()), input);
+ }
+}
+
+// Expand the input so that it is at least K times as big as block size
+std::string Expand(const std::string& input) {
+ static const int K = 3;
+ std::string data = input;
+ while (data.size() < K * snappy::kBlockSize) {
+ data += input;
+ }
+ return data;
+}
+
+int Verify(const std::string& input) {
+ VLOG(1) << "Verifying input of size " << input.size();
+
+ // Compress using string based routines
+ const int result = VerifyString(input);
+
+ // Verify using sink based routines
+ VerifyStringSink(input);
+
+ VerifyNonBlockedCompression(input);
+ VerifyIOVec(input);
+ if (!input.empty()) {
+ const std::string expanded = Expand(input);
+ VerifyNonBlockedCompression(expanded);
+ VerifyIOVec(input);
+ }
+
+ return result;
+}
+
+bool IsValidCompressedBuffer(const std::string& c) {
+ return snappy::IsValidCompressedBuffer(c.data(), c.size());
+}
+bool Uncompress(const std::string& c, std::string* u) {
+ return snappy::Uncompress(c.data(), c.size(), u);
+}
+
+// This test checks to ensure that snappy doesn't coredump if it gets
+// corrupted data.
+TEST(CorruptedTest, VerifyCorrupted) {
+ std::string source = "making sure we don't crash with corrupted input";
+ VLOG(1) << source;
+ std::string dest;
+ std::string uncmp;
+ snappy::Compress(source.data(), source.size(), &dest);
+
+ // Mess around with the data. It's hard to simulate all possible
+ // corruptions; this is just one example ...
+ CHECK_GT(dest.size(), 3);
+ dest[1]--;
+ dest[3]++;
+ // this really ought to fail.
+ CHECK(!IsValidCompressedBuffer(dest));
+ CHECK(!Uncompress(dest, &uncmp));
+
+ // This is testing for a security bug - a buffer that decompresses to 100k
+ // but we lie in the snappy header and only reserve 0 bytes of memory :)
+ source.resize(100000);
+ for (char& source_char : source) {
+ source_char = 'A';
+ }
+ snappy::Compress(source.data(), source.size(), &dest);
+ dest[0] = dest[1] = dest[2] = dest[3] = 0;
+ CHECK(!IsValidCompressedBuffer(dest));
+ CHECK(!Uncompress(dest, &uncmp));
+
+ if (sizeof(void *) == 4) {
+ // Another security check; check a crazy big length can't DoS us with an
+ // over-allocation.
+ // Currently this is done only for 32-bit builds. On 64-bit builds,
+ // where 3 GB might be an acceptable allocation size, Uncompress()
+ // attempts to decompress, and sometimes causes the test to run out of
+ // memory.
+ dest[0] = dest[1] = dest[2] = dest[3] = '\xff';
+ // This decodes to a really large size, i.e., about 3 GB.
+ dest[4] = 'k';
+ CHECK(!IsValidCompressedBuffer(dest));
+ CHECK(!Uncompress(dest, &uncmp));
+ } else {
+ LOG(WARNING) << "Crazy decompression lengths not checked on 64-bit build";
+ }
+
+ // This decodes to about 2 MB; much smaller, but should still fail.
+ dest[0] = dest[1] = dest[2] = '\xff';
+ dest[3] = 0x00;
+ CHECK(!IsValidCompressedBuffer(dest));
+ CHECK(!Uncompress(dest, &uncmp));
+
+ // try reading stuff in from a bad file.
+ for (int i = 1; i <= 3; ++i) {
+ std::string data =
+ ReadTestDataFile(StrFormat("baddata%d.snappy", i).c_str(), 0);
+ std::string uncmp;
+ // check that we don't return a crazy length
+ size_t ulen;
+ CHECK(!snappy::GetUncompressedLength(data.data(), data.size(), &ulen)
+ || (ulen < (1<<20)));
+ uint32_t ulen2;
+ snappy::ByteArraySource source(data.data(), data.size());
+ CHECK(!snappy::GetUncompressedLength(&source, &ulen2) ||
+ (ulen2 < (1<<20)));
+ CHECK(!IsValidCompressedBuffer(data));
+ CHECK(!Uncompress(data, &uncmp));
+ }
+}
+
+// Helper routines to construct arbitrary compressed strings.
+// These mirror the compression code in snappy.cc, but are copied
+// here so that we can bypass some limitations in the how snappy.cc
+// invokes these routines.
+void AppendLiteral(std::string* dst, const std::string& literal) {
+ if (literal.empty()) return;
+ int n = literal.size() - 1;
+ if (n < 60) {
+ // Fit length in tag byte
+ dst->push_back(0 | (n << 2));
+ } else {
+ // Encode in upcoming bytes
+ char number[4];
+ int count = 0;
+ while (n > 0) {
+ number[count++] = n & 0xff;
+ n >>= 8;
+ }
+ dst->push_back(0 | ((59+count) << 2));
+ *dst += std::string(number, count);
+ }
+ *dst += literal;
+}
+
+void AppendCopy(std::string* dst, int offset, int length) {
+ while (length > 0) {
+ // Figure out how much to copy in one shot
+ int to_copy;
+ if (length >= 68) {
+ to_copy = 64;
+ } else if (length > 64) {
+ to_copy = 60;
+ } else {
+ to_copy = length;
+ }
+ length -= to_copy;
+
+ if ((to_copy >= 4) && (to_copy < 12) && (offset < 2048)) {
+ assert(to_copy-4 < 8); // Must fit in 3 bits
+ dst->push_back(1 | ((to_copy-4) << 2) | ((offset >> 8) << 5));
+ dst->push_back(offset & 0xff);
+ } else if (offset < 65536) {
+ dst->push_back(2 | ((to_copy-1) << 2));
+ dst->push_back(offset & 0xff);
+ dst->push_back(offset >> 8);
+ } else {
+ dst->push_back(3 | ((to_copy-1) << 2));
+ dst->push_back(offset & 0xff);
+ dst->push_back((offset >> 8) & 0xff);
+ dst->push_back((offset >> 16) & 0xff);
+ dst->push_back((offset >> 24) & 0xff);
+ }
+ }
+}
+
+TEST(Snappy, SimpleTests) {
+ Verify("");
+ Verify("a");
+ Verify("ab");
+ Verify("abc");
+
+ Verify("aaaaaaa" + std::string(16, 'b') + std::string("aaaaa") + "abc");
+ Verify("aaaaaaa" + std::string(256, 'b') + std::string("aaaaa") + "abc");
+ Verify("aaaaaaa" + std::string(2047, 'b') + std::string("aaaaa") + "abc");
+ Verify("aaaaaaa" + std::string(65536, 'b') + std::string("aaaaa") + "abc");
+ Verify("abcaaaaaaa" + std::string(65536, 'b') + std::string("aaaaa") + "abc");
+}
+
+// Regression test for cr/345340892.
+TEST(Snappy, AppendSelfPatternExtensionEdgeCases) {
+ Verify("abcabcabcabcabcabcab");
+ Verify("abcabcabcabcabcabcab0123456789ABCDEF");
+
+ Verify("abcabcabcabcabcabcabcabcabcabcabcabc");
+ Verify("abcabcabcabcabcabcabcabcabcabcabcabc0123456789ABCDEF");
+}
+
+// Regression test for cr/345340892.
+TEST(Snappy, AppendSelfPatternExtensionEdgeCasesExhaustive) {
+ std::mt19937 rng;
+ std::uniform_int_distribution<int> uniform_byte(0, 255);
+ for (int pattern_size = 1; pattern_size <= 18; ++pattern_size) {
+ for (int length = 1; length <= 64; ++length) {
+ for (int extra_bytes_after_pattern : {0, 1, 15, 16, 128}) {
+ const int size = pattern_size + length + extra_bytes_after_pattern;
+ std::string input;
+ input.resize(size);
+ for (int i = 0; i < pattern_size; ++i) {
+ input[i] = 'a' + i;
+ }
+ for (int i = 0; i < length; ++i) {
+ input[pattern_size + i] = input[i];
+ }
+ for (int i = 0; i < extra_bytes_after_pattern; ++i) {
+ input[pattern_size + length + i] =
+ static_cast<char>(uniform_byte(rng));
+ }
+ Verify(input);
+ }
+ }
+ }
+}
+
+// Verify max blowup (lots of four-byte copies)
+TEST(Snappy, MaxBlowup) {
+ std::mt19937 rng;
+ std::uniform_int_distribution<int> uniform_byte(0, 255);
+ std::string input;
+ for (int i = 0; i < 80000; ++i)
+ input.push_back(static_cast<char>(uniform_byte(rng)));
+
+ for (int i = 0; i < 80000; i += 4) {
+ std::string four_bytes(input.end() - i - 4, input.end() - i);
+ input.append(four_bytes);
+ }
+ Verify(input);
+}
+
+TEST(Snappy, RandomData) {
+ std::minstd_rand0 rng(snappy::GetFlag(FLAGS_test_random_seed));
+ std::uniform_int_distribution<int> uniform_0_to_3(0, 3);
+ std::uniform_int_distribution<int> uniform_0_to_8(0, 8);
+ std::uniform_int_distribution<int> uniform_byte(0, 255);
+ std::uniform_int_distribution<size_t> uniform_4k(0, 4095);
+ std::uniform_int_distribution<size_t> uniform_64k(0, 65535);
+ std::bernoulli_distribution one_in_ten(1.0 / 10);
+
+ constexpr int num_ops = 20000;
+ for (int i = 0; i < num_ops; ++i) {
+ if ((i % 1000) == 0) {
+ VLOG(0) << "Random op " << i << " of " << num_ops;
+ }
+
+ std::string x;
+ size_t len = uniform_4k(rng);
+ if (i < 100) {
+ len = 65536 + uniform_64k(rng);
+ }
+ while (x.size() < len) {
+ int run_len = 1;
+ if (one_in_ten(rng)) {
+ int skewed_bits = uniform_0_to_8(rng);
+ // int is guaranteed to hold at least 16 bits, this uses at most 8 bits.
+ std::uniform_int_distribution<int> skewed_low(0,
+ (1 << skewed_bits) - 1);
+ run_len = skewed_low(rng);
+ }
+ char c = static_cast<char>(uniform_byte(rng));
+ if (i >= 100) {
+ int skewed_bits = uniform_0_to_3(rng);
+ // int is guaranteed to hold at least 16 bits, this uses at most 3 bits.
+ std::uniform_int_distribution<int> skewed_low(0,
+ (1 << skewed_bits) - 1);
+ c = static_cast<char>(skewed_low(rng));
+ }
+ while (run_len-- > 0 && x.size() < len) {
+ x.push_back(c);
+ }
+ }
+
+ Verify(x);
+ }
+}
+
+TEST(Snappy, FourByteOffset) {
+ // The new compressor cannot generate four-byte offsets since
+ // it chops up the input into 32KB pieces. So we hand-emit the
+ // copy manually.
+
+ // The two fragments that make up the input string.
+ std::string fragment1 = "012345689abcdefghijklmnopqrstuvwxyz";
+ std::string fragment2 = "some other string";
+
+ // How many times each fragment is emitted.
+ const int n1 = 2;
+ const int n2 = 100000 / fragment2.size();
+ const size_t length = n1 * fragment1.size() + n2 * fragment2.size();
+
+ std::string compressed;
+ Varint::Append32(&compressed, length);
+
+ AppendLiteral(&compressed, fragment1);
+ std::string src = fragment1;
+ for (int i = 0; i < n2; ++i) {
+ AppendLiteral(&compressed, fragment2);
+ src += fragment2;
+ }
+ AppendCopy(&compressed, src.size(), fragment1.size());
+ src += fragment1;
+ CHECK_EQ(length, src.size());
+
+ std::string uncompressed;
+ CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+ CHECK(snappy::Uncompress(compressed.data(), compressed.size(),
+ &uncompressed));
+ CHECK_EQ(uncompressed, src);
+}
+
+TEST(Snappy, IOVecEdgeCases) {
+ // Test some tricky edge cases in the iovec output that are not necessarily
+ // exercised by random tests.
+
+ // Our output blocks look like this initially (the last iovec is bigger
+ // than depicted):
+ // [ ] [ ] [ ] [ ] [ ]
+ static const int kLengths[] = { 2, 1, 4, 8, 128 };
+
+ struct iovec iov[ARRAYSIZE(kLengths)];
+ for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+ iov[i].iov_base = new char[kLengths[i]];
+ iov[i].iov_len = kLengths[i];
+ }
+
+ std::string compressed;
+ Varint::Append32(&compressed, 22);
+
+ // A literal whose output crosses three blocks.
+ // [ab] [c] [123 ] [ ] [ ]
+ AppendLiteral(&compressed, "abc123");
+
+ // A copy whose output crosses two blocks (source and destination
+ // segments marked).
+ // [ab] [c] [1231] [23 ] [ ]
+ // ^--^ --
+ AppendCopy(&compressed, 3, 3);
+
+ // A copy where the input is, at first, in the block before the output:
+ //
+ // [ab] [c] [1231] [231231 ] [ ]
+ // ^--- ^---
+ // Then during the copy, the pointers move such that the input and
+ // output pointers are in the same block:
+ //
+ // [ab] [c] [1231] [23123123] [ ]
+ // ^- ^-
+ // And then they move again, so that the output pointer is no longer
+ // in the same block as the input pointer:
+ // [ab] [c] [1231] [23123123] [123 ]
+ // ^-- ^--
+ AppendCopy(&compressed, 6, 9);
+
+ // Finally, a copy where the input is from several blocks back,
+ // and it also crosses three blocks:
+ //
+ // [ab] [c] [1231] [23123123] [123b ]
+ // ^ ^
+ // [ab] [c] [1231] [23123123] [123bc ]
+ // ^ ^
+ // [ab] [c] [1231] [23123123] [123bc12 ]
+ // ^- ^-
+ AppendCopy(&compressed, 17, 4);
+
+ CHECK(snappy::RawUncompressToIOVec(
+ compressed.data(), compressed.size(), iov, ARRAYSIZE(iov)));
+ CHECK_EQ(0, memcmp(iov[0].iov_base, "ab", 2));
+ CHECK_EQ(0, memcmp(iov[1].iov_base, "c", 1));
+ CHECK_EQ(0, memcmp(iov[2].iov_base, "1231", 4));
+ CHECK_EQ(0, memcmp(iov[3].iov_base, "23123123", 8));
+ CHECK_EQ(0, memcmp(iov[4].iov_base, "123bc12", 7));
+
+ for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+ delete[] reinterpret_cast<char *>(iov[i].iov_base);
+ }
+}
+
+TEST(Snappy, IOVecLiteralOverflow) {
+ static const int kLengths[] = { 3, 4 };
+
+ struct iovec iov[ARRAYSIZE(kLengths)];
+ for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+ iov[i].iov_base = new char[kLengths[i]];
+ iov[i].iov_len = kLengths[i];
+ }
+
+ std::string compressed;
+ Varint::Append32(&compressed, 8);
+
+ AppendLiteral(&compressed, "12345678");
+
+ CHECK(!snappy::RawUncompressToIOVec(
+ compressed.data(), compressed.size(), iov, ARRAYSIZE(iov)));
+
+ for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+ delete[] reinterpret_cast<char *>(iov[i].iov_base);
+ }
+}
+
+TEST(Snappy, IOVecCopyOverflow) {
+ static const int kLengths[] = { 3, 4 };
+
+ struct iovec iov[ARRAYSIZE(kLengths)];
+ for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+ iov[i].iov_base = new char[kLengths[i]];
+ iov[i].iov_len = kLengths[i];
+ }
+
+ std::string compressed;
+ Varint::Append32(&compressed, 8);
+
+ AppendLiteral(&compressed, "123");
+ AppendCopy(&compressed, 3, 5);
+
+ CHECK(!snappy::RawUncompressToIOVec(
+ compressed.data(), compressed.size(), iov, ARRAYSIZE(iov)));
+
+ for (int i = 0; i < ARRAYSIZE(kLengths); ++i) {
+ delete[] reinterpret_cast<char *>(iov[i].iov_base);
+ }
+}
+
+bool CheckUncompressedLength(const std::string& compressed, size_t* ulength) {
+ const bool result1 = snappy::GetUncompressedLength(compressed.data(),
+ compressed.size(),
+ ulength);
+
+ snappy::ByteArraySource source(compressed.data(), compressed.size());
+ uint32_t length;
+ const bool result2 = snappy::GetUncompressedLength(&source, &length);
+ CHECK_EQ(result1, result2);
+ return result1;
+}
+
+TEST(SnappyCorruption, TruncatedVarint) {
+ std::string compressed, uncompressed;
+ size_t ulength;
+ compressed.push_back('\xf0');
+ CHECK(!CheckUncompressedLength(compressed, &ulength));
+ CHECK(!snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+ CHECK(!snappy::Uncompress(compressed.data(), compressed.size(),
+ &uncompressed));
+}
+
+TEST(SnappyCorruption, UnterminatedVarint) {
+ std::string compressed, uncompressed;
+ size_t ulength;
+ compressed.push_back('\x80');
+ compressed.push_back('\x80');
+ compressed.push_back('\x80');
+ compressed.push_back('\x80');
+ compressed.push_back('\x80');
+ compressed.push_back(10);
+ CHECK(!CheckUncompressedLength(compressed, &ulength));
+ CHECK(!snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+ CHECK(!snappy::Uncompress(compressed.data(), compressed.size(),
+ &uncompressed));
+}
+
+TEST(SnappyCorruption, OverflowingVarint) {
+ std::string compressed, uncompressed;
+ size_t ulength;
+ compressed.push_back('\xfb');
+ compressed.push_back('\xff');
+ compressed.push_back('\xff');
+ compressed.push_back('\xff');
+ compressed.push_back('\x7f');
+ CHECK(!CheckUncompressedLength(compressed, &ulength));
+ CHECK(!snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+ CHECK(!snappy::Uncompress(compressed.data(), compressed.size(),
+ &uncompressed));
+}
+
+TEST(Snappy, ReadPastEndOfBuffer) {
+ // Check that we do not read past end of input
+
+ // Make a compressed string that ends with a single-byte literal
+ std::string compressed;
+ Varint::Append32(&compressed, 1);
+ AppendLiteral(&compressed, "x");
+
+ std::string uncompressed;
+ DataEndingAtUnreadablePage c(compressed);
+ CHECK(snappy::Uncompress(c.data(), c.size(), &uncompressed));
+ CHECK_EQ(uncompressed, std::string("x"));
+}
+
+// Check for an infinite loop caused by a copy with offset==0
+TEST(Snappy, ZeroOffsetCopy) {
+ const char* compressed = "\x40\x12\x00\x00";
+ // \x40 Length (must be > kMaxIncrementCopyOverflow)
+ // \x12\x00\x00 Copy with offset==0, length==5
+ char uncompressed[100];
+ EXPECT_FALSE(snappy::RawUncompress(compressed, 4, uncompressed));
+}
+
+TEST(Snappy, ZeroOffsetCopyValidation) {
+ const char* compressed = "\x05\x12\x00\x00";
+ // \x05 Length
+ // \x12\x00\x00 Copy with offset==0, length==5
+ EXPECT_FALSE(snappy::IsValidCompressedBuffer(compressed, 4));
+}
+
+int TestFindMatchLength(const char* s1, const char *s2, unsigned length) {
+ uint64_t data;
+ std::pair<size_t, bool> p =
+ snappy::internal::FindMatchLength(s1, s2, s2 + length, &data);
+ CHECK_EQ(p.first < 8, p.second);
+ return p.first;
+}
+
+TEST(Snappy, FindMatchLength) {
+ // Exercise all different code paths through the function.
+ // 64-bit version:
+
+ // Hit s1_limit in 64-bit loop, hit s1_limit in single-character loop.
+ EXPECT_EQ(6, TestFindMatchLength("012345", "012345", 6));
+ EXPECT_EQ(11, TestFindMatchLength("01234567abc", "01234567abc", 11));
+
+ // Hit s1_limit in 64-bit loop, find a non-match in single-character loop.
+ EXPECT_EQ(9, TestFindMatchLength("01234567abc", "01234567axc", 9));
+
+ // Same, but edge cases.
+ EXPECT_EQ(11, TestFindMatchLength("01234567abc!", "01234567abc!", 11));
+ EXPECT_EQ(11, TestFindMatchLength("01234567abc!", "01234567abc?", 11));
+
+ // Find non-match at once in first loop.
+ EXPECT_EQ(0, TestFindMatchLength("01234567xxxxxxxx", "?1234567xxxxxxxx", 16));
+ EXPECT_EQ(1, TestFindMatchLength("01234567xxxxxxxx", "0?234567xxxxxxxx", 16));
+ EXPECT_EQ(4, TestFindMatchLength("01234567xxxxxxxx", "01237654xxxxxxxx", 16));
+ EXPECT_EQ(7, TestFindMatchLength("01234567xxxxxxxx", "0123456?xxxxxxxx", 16));
+
+ // Find non-match in first loop after one block.
+ EXPECT_EQ(8, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+ "abcdefgh?1234567xxxxxxxx", 24));
+ EXPECT_EQ(9, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+ "abcdefgh0?234567xxxxxxxx", 24));
+ EXPECT_EQ(12, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+ "abcdefgh01237654xxxxxxxx", 24));
+ EXPECT_EQ(15, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+ "abcdefgh0123456?xxxxxxxx", 24));
+
+ // 32-bit version:
+
+ // Short matches.
+ EXPECT_EQ(0, TestFindMatchLength("01234567", "?1234567", 8));
+ EXPECT_EQ(1, TestFindMatchLength("01234567", "0?234567", 8));
+ EXPECT_EQ(2, TestFindMatchLength("01234567", "01?34567", 8));
+ EXPECT_EQ(3, TestFindMatchLength("01234567", "012?4567", 8));
+ EXPECT_EQ(4, TestFindMatchLength("01234567", "0123?567", 8));
+ EXPECT_EQ(5, TestFindMatchLength("01234567", "01234?67", 8));
+ EXPECT_EQ(6, TestFindMatchLength("01234567", "012345?7", 8));
+ EXPECT_EQ(7, TestFindMatchLength("01234567", "0123456?", 8));
+ EXPECT_EQ(7, TestFindMatchLength("01234567", "0123456?", 7));
+ EXPECT_EQ(7, TestFindMatchLength("01234567!", "0123456??", 7));
+
+ // Hit s1_limit in 32-bit loop, hit s1_limit in single-character loop.
+ EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd", "xxxxxxabcd", 10));
+ EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd?", "xxxxxxabcd?", 10));
+ EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcdef", "xxxxxxabcdef", 13));
+
+ // Same, but edge cases.
+ EXPECT_EQ(12, TestFindMatchLength("xxxxxx0123abc!", "xxxxxx0123abc!", 12));
+ EXPECT_EQ(12, TestFindMatchLength("xxxxxx0123abc!", "xxxxxx0123abc?", 12));
+
+ // Hit s1_limit in 32-bit loop, find a non-match in single-character loop.
+ EXPECT_EQ(11, TestFindMatchLength("xxxxxx0123abc", "xxxxxx0123axc", 13));
+
+ // Find non-match at once in first loop.
+ EXPECT_EQ(6, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+ "xxxxxx?123xxxxxxxx", 18));
+ EXPECT_EQ(7, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+ "xxxxxx0?23xxxxxxxx", 18));
+ EXPECT_EQ(8, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+ "xxxxxx0132xxxxxxxx", 18));
+ EXPECT_EQ(9, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+ "xxxxxx012?xxxxxxxx", 18));
+
+ // Same, but edge cases.
+ EXPECT_EQ(6, TestFindMatchLength("xxxxxx0123", "xxxxxx?123", 10));
+ EXPECT_EQ(7, TestFindMatchLength("xxxxxx0123", "xxxxxx0?23", 10));
+ EXPECT_EQ(8, TestFindMatchLength("xxxxxx0123", "xxxxxx0132", 10));
+ EXPECT_EQ(9, TestFindMatchLength("xxxxxx0123", "xxxxxx012?", 10));
+
+ // Find non-match in first loop after one block.
+ EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd0123xx",
+ "xxxxxxabcd?123xx", 16));
+ EXPECT_EQ(11, TestFindMatchLength("xxxxxxabcd0123xx",
+ "xxxxxxabcd0?23xx", 16));
+ EXPECT_EQ(12, TestFindMatchLength("xxxxxxabcd0123xx",
+ "xxxxxxabcd0132xx", 16));
+ EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcd0123xx",
+ "xxxxxxabcd012?xx", 16));
+
+ // Same, but edge cases.
+ EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd?123", 14));
+ EXPECT_EQ(11, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd0?23", 14));
+ EXPECT_EQ(12, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd0132", 14));
+ EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd012?", 14));
+}
+
+TEST(Snappy, FindMatchLengthRandom) {
+ constexpr int kNumTrials = 10000;
+ constexpr int kTypicalLength = 10;
+ std::minstd_rand0 rng(snappy::GetFlag(FLAGS_test_random_seed));
+ std::uniform_int_distribution<int> uniform_byte(0, 255);
+ std::bernoulli_distribution one_in_two(1.0 / 2);
+ std::bernoulli_distribution one_in_typical_length(1.0 / kTypicalLength);
+
+ for (int i = 0; i < kNumTrials; ++i) {
+ std::string s, t;
+ char a = static_cast<char>(uniform_byte(rng));
+ char b = static_cast<char>(uniform_byte(rng));
+ while (!one_in_typical_length(rng)) {
+ s.push_back(one_in_two(rng) ? a : b);
+ t.push_back(one_in_two(rng) ? a : b);
+ }
+ DataEndingAtUnreadablePage u(s);
+ DataEndingAtUnreadablePage v(t);
+ size_t matched = TestFindMatchLength(u.data(), v.data(), t.size());
+ if (matched == t.size()) {
+ EXPECT_EQ(s, t);
+ } else {
+ EXPECT_NE(s[matched], t[matched]);
+ for (size_t j = 0; j < matched; ++j) {
+ EXPECT_EQ(s[j], t[j]);
+ }
+ }
+ }
+}
+
+uint16_t MakeEntry(unsigned int extra, unsigned int len,
+ unsigned int copy_offset) {
+ // Check that all of the fields fit within the allocated space
+ assert(extra == (extra & 0x7)); // At most 3 bits
+ assert(copy_offset == (copy_offset & 0x7)); // At most 3 bits
+ assert(len == (len & 0x7f)); // At most 7 bits
+ return len | (copy_offset << 8) | (extra << 11);
+}
+
+// Check that the decompression table is correct, and optionally print out
+// the computed one.
+TEST(Snappy, VerifyCharTable) {
+ using snappy::internal::LITERAL;
+ using snappy::internal::COPY_1_BYTE_OFFSET;
+ using snappy::internal::COPY_2_BYTE_OFFSET;
+ using snappy::internal::COPY_4_BYTE_OFFSET;
+ using snappy::internal::char_table;
+
+ uint16_t dst[256];
+
+ // Place invalid entries in all places to detect missing initialization
+ int assigned = 0;
+ for (int i = 0; i < 256; ++i) {
+ dst[i] = 0xffff;
+ }
+
+ // Small LITERAL entries. We store (len-1) in the top 6 bits.
+ for (uint8_t len = 1; len <= 60; ++len) {
+ dst[LITERAL | ((len - 1) << 2)] = MakeEntry(0, len, 0);
+ assigned++;
+ }
+
+ // Large LITERAL entries. We use 60..63 in the high 6 bits to
+ // encode the number of bytes of length info that follow the opcode.
+ for (uint8_t extra_bytes = 1; extra_bytes <= 4; ++extra_bytes) {
+ // We set the length field in the lookup table to 1 because extra
+ // bytes encode len-1.
+ dst[LITERAL | ((extra_bytes + 59) << 2)] = MakeEntry(extra_bytes, 1, 0);
+ assigned++;
+ }
+
+ // COPY_1_BYTE_OFFSET.
+ //
+ // The tag byte in the compressed data stores len-4 in 3 bits, and
+ // offset/256 in 5 bits. offset%256 is stored in the next byte.
+ //
+ // This format is used for length in range [4..11] and offset in
+ // range [0..2047]
+ for (uint8_t len = 4; len < 12; ++len) {
+ for (uint16_t offset = 0; offset < 2048; offset += 256) {
+ uint8_t offset_high = static_cast<uint8_t>(offset >> 8);
+ dst[COPY_1_BYTE_OFFSET | ((len - 4) << 2) | (offset_high << 5)] =
+ MakeEntry(1, len, offset_high);
+ assigned++;
+ }
+ }
+
+ // COPY_2_BYTE_OFFSET.
+ // Tag contains len-1 in top 6 bits, and offset in next two bytes.
+ for (uint8_t len = 1; len <= 64; ++len) {
+ dst[COPY_2_BYTE_OFFSET | ((len - 1) << 2)] = MakeEntry(2, len, 0);
+ assigned++;
+ }
+
+ // COPY_4_BYTE_OFFSET.
+ // Tag contents len-1 in top 6 bits, and offset in next four bytes.
+ for (uint8_t len = 1; len <= 64; ++len) {
+ dst[COPY_4_BYTE_OFFSET | ((len - 1) << 2)] = MakeEntry(4, len, 0);
+ assigned++;
+ }
+
+ // Check that each entry was initialized exactly once.
+ EXPECT_EQ(256, assigned) << "Assigned only " << assigned << " of 256";
+ for (int i = 0; i < 256; ++i) {
+ EXPECT_NE(0xffff, dst[i]) << "Did not assign byte " << i;
+ }
+
+ if (snappy::GetFlag(FLAGS_snappy_dump_decompression_table)) {
+ std::printf("static const uint16_t char_table[256] = {\n ");
+ for (int i = 0; i < 256; ++i) {
+ std::printf("0x%04x%s",
+ dst[i],
+ ((i == 255) ? "\n" : (((i % 8) == 7) ? ",\n " : ", ")));
+ }
+ std::printf("};\n");
+ }
+
+ // Check that computed table matched recorded table.
+ for (int i = 0; i < 256; ++i) {
+ EXPECT_EQ(dst[i], char_table[i]) << "Mismatch in byte " << i;
+ }
+}
+
+TEST(Snappy, TestBenchmarkFiles) {
+ for (int i = 0; i < ARRAYSIZE(kTestDataFiles); ++i) {
+ Verify(ReadTestDataFile(kTestDataFiles[i].filename,
+ kTestDataFiles[i].size_limit));
+ }
+}
+
+} // namespace
+
+} // namespace snappy