cosmopolitan/libc/nexgen32e/lz4.h
Justine Tunney fa20edc44d
Reduce header complexity
- Remove most __ASSEMBLER__ __LINKER__ ifdefs
- Rename libc/intrin/bits.h to libc/serialize.h
- Block pthread cancelation in fchmodat() polyfill
- Remove `clang-format off` statements in third_party
2023-11-28 14:39:42 -08:00

71 lines
4.6 KiB
C

#ifndef COSMOPOLITAN_LIBC_LZ4_H_
#define COSMOPOLITAN_LIBC_LZ4_H_
#include "libc/serialize.h"
/*───────────────────────────────────────────────────────────────────────────│─╗
│ cosmopolitan § lz4 ─╬─│┼
╚────────────────────────────────────────────────────────────────────────────│─╝
LZ4 is a brilliant framing format for REP MOVSB designed by Yann Collet.
@see https://github.com/lz4/lz4/blob/master/doc/lz4_Frame_format.md
@see https://github.com/lz4/lz4/blob/master/doc/lz4_Block_format.md
@see http://ticki.github.io/blog/how-lz4-works/ */
#define LZ4_EOF 0
#define LZ4_VERSION 1
#define LZ4_MAGICNUMBER 0x184D2204
#define LZ4_SKIPPABLE0 0x184D2A50
#define LZ4_SKIPPABLEMASK 0xFFFFFFF0
#define LZ4_MAXHEADERSIZE (MAGICNUMBER_SIZE + 2 + 8 + 4 + 1)
#define LZ4_BLOCKMAXSIZE_64KB 4
#define LZ4_BLOCKMAXSIZE_256KB 5
#define LZ4_BLOCKMAXSIZE_1MB 6
#define LZ4_BLOCKMAXSIZE_4MB 7
COSMOPOLITAN_C_START_
/*───────────────────────────────────────────────────────────────────────────│─╗
│ cosmopolitan § lz4 » frames ─╬─│┼
╚────────────────────────────────────────────────────────────────────────────│*/
#define LZ4_MAGIC(FRAME) READ32LE(FRAME)
#define LZ4_FRAME_VERSION(FRAME) ((_LZ4_FRAME_FLG(FRAME) >> 6) & 3)
#define LZ4_FRAME_BLOCKINDEPENDENCE(FRAME) ((_LZ4_FRAME_FLG(FRAME) >> 5) & 1)
#define LZ4_FRAME_BLOCKCHECKSUMFLAG(FRAME) ((_LZ4_FRAME_FLG(FRAME) >> 4) & 1)
#define LZ4_FRAME_BLOCKCONTENTSIZEFLAG(FRAME) ((_LZ4_FRAME_FLG(FRAME) >> 3) & 1)
#define LZ4_FRAME_BLOCKCONTENTCHECKSUMFLAG(FRAME) \
((_LZ4_FRAME_FLG(FRAME) >> 2) & 1)
#define LZ4_FRAME_DICTIONARYIDFLAG(FRAME) ((_LZ4_FRAME_FLG(FRAME) >> 0) & 1)
#define LZ4_FRAME_BLOCKMAXSIZE(FRAME) ((_LZ4_FRAME_BD(FRAME) >> 4) & 7)
#define LZ4_FRAME_RESERVED1(FRAME) ((_LZ4_FRAME_FLG(FRAME) >> 1) & 1)
#define LZ4_FRAME_RESERVED2(FRAME) ((_LZ4_FRAME_BD(FRAME) >> 7) & 1)
#define LZ4_FRAME_RESERVED3(FRAME) ((_LZ4_FRAME_BD(FRAME) >> 0) & 15)
#define LZ4_FRAME_BLOCKCONTENTSIZE(FRAME) \
(LZ4_FRAME_BLOCKCONTENTSIZEFLAG(FRAME) ? READ64LE((FRAME) + 4 + 1 + 1) : 0)
#define LZ4_FRAME_DICTIONARYID(FRAME) \
(LZ4_FRAME_DICTIONARYIDFLAG(FRAME) \
? READ32LE(((FRAME) + 4 + 1 + 1 + \
8 * LZ4_FRAME_BLOCKCONTENTSIZEFLAG(FRAME))) \
: 0)
#define LZ4_FRAME_HEADERCHECKSUM(FRAME) \
(*((FRAME) + 4 + 1 + 1 + 8 * LZ4_FRAME_BLOCKCONTENTSIZEFLAG(FRAME) + \
4 * LZ4_FRAME_DICTIONARYIDFLAG(FRAME)))
#define LZ4_FRAME_HEADERSIZE(FRAME) \
(4 + 1 + 1 + 8 * LZ4_FRAME_BLOCKCONTENTSIZEFLAG(FRAME) + \
4 * LZ4_FRAME_DICTIONARYIDFLAG(FRAME) + 1)
#define _LZ4_FRAME_FLG(FRAME) (*((FRAME) + 4))
#define _LZ4_FRAME_BD(FRAME) (*((FRAME) + 5))
/*───────────────────────────────────────────────────────────────────────────│─╗
│ cosmopolitan § lz4 » blocks ─╬─│┼
╚────────────────────────────────────────────────────────────────────────────│*/
#define LZ4_BLOCK_DATA(block) (block + sizeof(uint32_t))
#define LZ4_BLOCK_DATASIZE(block) (READ32LE(block) & 0x7fffffff)
#define LZ4_BLOCK_ISEOF(block) (READ32LE(block) == LZ4_EOF)
#define LZ4_BLOCK_ISCOMPRESSED(block) ((READ32LE(block) & 0x80000000) == 0)
#define LZ4_BLOCK_SIZE(frame, block) \
(sizeof(uint32_t) + LZ4_BLOCK_DATASIZE(block) + \
(LZ4_FRAME_BLOCKCHECKSUMFLAG(frame) ? sizeof(uint8_t) : 0))
COSMOPOLITAN_C_END_
#endif /* COSMOPOLITAN_LIBC_LZ4_H_ */