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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. + +[](https://travis-ci.org/google/snappy) +[](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 |