sh

Tiny suckless compression library.

Features

• single header library, no linking bullcrap:
  • fewer than 200 lines, extremely small and nonbloated
  • both compression and decompression are streaming! no file buffers needed
  • constant memory complexity, super low RAM requirements (a few bytes)
  • linear time complexity, super fast
  • ABSOLUTELY ZERO dependencies, not even standard library is used
• two executable utilities using the library also included:
  • sh: Super simple, fast, streaming, max. compression ratio 33%.
  • sushh: Non-streaming, repeatedly compresses as long as file size reduces, potentially compresses more (even to less than 1%!) but is slower, eats more RAM and uses malloc. Guarantees to never enlarge a file by more than 1 byte (unlike normal shitpress)!
• generally usable for any type of data, not assuming any specific use (such as file compression), i.e. can be used in any wild hacking style (e.g. to compress stuff in RAM on low-RAM embedded computers etc.)

Here are some measured stats for sh , sushh and a commonly used lz4 utility (sizes in bytes):

input	orig. size	compressed (shitpress)	compressed (supershit.)	compr. r. (shitpr.)	compr. r. (supersh.)	compressed (lz4)	compr. r. (lz4)
100000 "A"s txt	100002	33339	134	33.3%	0.1% !!!	422	42.0%
WM Commons screens. raw	3072000	1522151	1018285	49.5%	33.1%	721531	23.4%
sh binary	30888	16995	16896	55.0%	54.7%	12859	41.6%
sh source	4886	3834	3836	78.4%	78.5%	580	75.3%
Wikip. main page HTML	96085	78957	78959	82.1%	82.1%	32459	33.7%
Flatland (txt book)	219615	197874	197876	90.1%	90.1%	135782	61.8%
100000 pi digits txt	100002	94254	94256	94.2%	94.2%	95354	95.3%
Lenna raw image	1048576	1023261	1023263	97.5%	97.5%	1039481	99.1%
Willhelm scr. raw audio	155858	152170	152172	97.6%	97.6%	152434	97.8%
100% random data	1024	1027	1025	100.2%	100.0%	1043	101.8%
forged malicious data	100	200	101	200.0%	101.0%	30	30.0%

Guide