Small Deflate

sdefl is a small bare bone lossless compression library in ANSI C (ISO C90) that implements the Deflate (RFC 1951) compressed data format specification standard.

sdefl is mainly tuned to get as much speed and compression ratio from as little code as needed to keep the implementation as concise as possible. In addition since this library implements the Deflate standard some limitations including a small match window of only 32kb apply. So don't expect comparable speed or compression ratio to some of the newer algorithms.

Features

• Portable single header and source file duo written in ANSI C (ISO C90)
• Small implementation
  • Static Deflate: 256 LoC
  • Adaptive Deflate: 480 LoC
  • Inflate: 150 LoC
• Dual license with either MIT or public domain
• Webassembly:
  • Deflate ~3.7 KB (~2.2KB compressed)
  • Inflate ~3.6 KB (~2.2KB compressed)

Usage

For deflating there are two versions. The first one uses static huffman tables and while the second use adaptive huffman tables. In terms of speed both are about the same while adaptive huffman tables provides better compression. But huffman table calculation takes additional 200 LoC in comparison to static tables. For either compression include the header and source pair into your project and include header. To actually compress memory first call sdefl_bound to calculate the maximum number of compressed output and allocate an compress output memory buffer and pass it along with your to compress input data and a compression level between SDEFL_LVL_MIN and SDEFL_LVL_MAX to the main compression function sdeflate.

For inflating add sinfl source and header into your project and include sinfl.h. To decompress a previously compressed block of memory call sinflate. Pass your compressed block along with its size and an allocated output buffer with size of the uncompressed block.

Benchmark

• sdefl: static huffman tables
• sdeflh: adaptive huffman tables

Compression

Results on the Silesia compression corpus:

• sdefl: static huffman tables
• sdeflh: adaptive huffman tables

License

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This software is available under 2 licenses -- choose whichever you prefer.
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ALTERNATIVE A - MIT License
Copyright (c) 2020 Micha Mettke
Permission is hereby granted, free of charge, to any person obtaining a copy of
this software and associated documentation files (the "Software"), to deal in
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so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
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ALTERNATIVE B - Public Domain (www.unlicense.org)
This is free and unencumbered software released into the public domain.
Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
software, either in source code form or as a compiled binary, for any purpose,
commercial or non-commercial, and by any means.
In jurisdictions that recognize copyright laws, the author or authors of this
software dedicate any and all copyright interest in the software to the public
domain. We make this dedication for the benefit of the public at large and to
the detriment of our heirs and successors. We intend this dedication to be an
overt act of relinquishment in perpetuity of all present and future rights to
this software under copyright law.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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