Adding upstream version 115.7.0esr.upstream/115.7.0esr

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

22 files changed, 6456 insertions, 0 deletions

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..7917d1bf05
--- /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
+
+```c++
+snappy::Compress(input.data(), input.size(), &output);
+```
+
+and similarly
+
+```c++
+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