mirror of
https://github.com/facebook/zstd.git
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278 lines
9.8 KiB
C
278 lines
9.8 KiB
C
/*
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zstd - standard compression library
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Header File for static linking only
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Copyright (C) 2014-2015, Yann Collet.
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BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are
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met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above
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copyright notice, this list of conditions and the following disclaimer
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in the documentation and/or other materials provided with the
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distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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You can contact the author at :
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- zstd source repository : https://github.com/Cyan4973/zstd
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- ztsd public forum : https://groups.google.com/forum/#!forum/lz4c
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*/
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#pragma once
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/* The objects defined into this file should be considered experimental.
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* They are not labelled stable, as their prototype may change in the future.
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* You can use them for tests, provide feedback, or if you can endure risk of future changes.
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*/
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#if defined (__cplusplus)
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extern "C" {
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#endif
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/* *************************************
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* Includes
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***************************************/
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#include "zstd.h"
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/* *************************************
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* Streaming functions
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***************************************/
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size_t ZSTD_compressBegin(ZSTD_CCtx* cctx, void* dst, size_t maxDstSize);
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size_t ZSTD_compressContinue(ZSTD_CCtx* cctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
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size_t ZSTD_compressEnd(ZSTD_CCtx* cctx, void* dst, size_t maxDstSize);
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typedef struct ZSTD_DCtx_s ZSTD_DCtx;
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ZSTD_DCtx* ZSTD_createDCtx(void);
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size_t ZSTD_resetDCtx(ZSTD_DCtx* dctx);
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size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx);
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size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx);
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size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, const void* src, size_t srcSize);
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/*
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Use above functions alternatively.
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ZSTD_nextSrcSizeToDecompress() tells how much bytes to provide as 'srcSize' to ZSTD_decompressContinue().
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ZSTD_decompressContinue() will use previous data blocks to improve compression if they are located prior to current block.
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Result is the number of bytes regenerated within 'dst'.
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It can be zero, which is not an error; it just means ZSTD_decompressContinue() has decoded some header.
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*/
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/* *************************************
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* Prefix - version detection
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***************************************/
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#define ZSTD_magicNumber 0xFD2FB523 /* v0.3 (current)*/
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/* *************************************
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* Error management
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***************************************/
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#include "error.h"
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/* *************************************
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* Function body to include
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***************************************/
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#include "mem.h"
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static size_t ZSTD_read_ARCH(const void* p) { size_t r; memcpy(&r, p, sizeof(r)); return r; }
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MEM_STATIC unsigned ZSTD_NbCommonBytes (register size_t val)
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{
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if (MEM_isLittleEndian())
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{
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if (MEM_64bits())
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{
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# if defined(_MSC_VER) && defined(_WIN64) && !defined(LZ4_FORCE_SW_BITCOUNT)
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unsigned long r = 0;
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_BitScanForward64( &r, (U64)val );
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return (int)(r>>3);
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# elif defined(__GNUC__) && (__GNUC__ >= 3) && !defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_ctzll((U64)val) >> 3);
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# else
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static const int DeBruijnBytePos[64] = { 0, 0, 0, 0, 0, 1, 1, 2, 0, 3, 1, 3, 1, 4, 2, 7, 0, 2, 3, 6, 1, 5, 3, 5, 1, 3, 4, 4, 2, 5, 6, 7, 7, 0, 1, 2, 3, 3, 4, 6, 2, 6, 5, 5, 3, 4, 5, 6, 7, 1, 2, 4, 6, 4, 4, 5, 7, 2, 6, 5, 7, 6, 7, 7 };
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return DeBruijnBytePos[((U64)((val & -(long long)val) * 0x0218A392CDABBD3FULL)) >> 58];
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# endif
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}
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else /* 32 bits */
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{
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# if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
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unsigned long r;
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_BitScanForward( &r, (U32)val );
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return (int)(r>>3);
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# elif defined(__GNUC__) && (__GNUC__ >= 3) && !defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_ctz((U32)val) >> 3);
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# else
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static const int DeBruijnBytePos[32] = { 0, 0, 3, 0, 3, 1, 3, 0, 3, 2, 2, 1, 3, 2, 0, 1, 3, 3, 1, 2, 2, 2, 2, 0, 3, 1, 2, 0, 1, 0, 1, 1 };
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return DeBruijnBytePos[((U32)((val & -(S32)val) * 0x077CB531U)) >> 27];
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# endif
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}
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}
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else /* Big Endian CPU */
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{
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if (MEM_32bits())
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{
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# if defined(_MSC_VER) && defined(_WIN64) && !defined(LZ4_FORCE_SW_BITCOUNT)
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unsigned long r = 0;
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_BitScanReverse64( &r, val );
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return (unsigned)(r>>3);
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# elif defined(__GNUC__) && (__GNUC__ >= 3) && !defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_clzll(val) >> 3);
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# else
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unsigned r;
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const unsigned n32 = sizeof(size_t)*4; /* calculate this way due to compiler complaining in 32-bits mode */
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if (!(val>>n32)) { r=4; } else { r=0; val>>=n32; }
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if (!(val>>16)) { r+=2; val>>=8; } else { val>>=24; }
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r += (!val);
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return r;
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# endif
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}
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else /* 32 bits */
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{
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# if defined(_MSC_VER) && !defined(LZ4_FORCE_SW_BITCOUNT)
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unsigned long r = 0;
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_BitScanReverse( &r, (unsigned long)val );
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return (unsigned)(r>>3);
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# elif defined(__GNUC__) && (__GNUC__ >= 3) && !defined(LZ4_FORCE_SW_BITCOUNT)
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return (__builtin_clz((U32)val) >> 3);
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# else
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unsigned r;
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if (!(val>>16)) { r=2; val>>=8; } else { r=0; val>>=24; }
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r += (!val);
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return r;
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# endif
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}
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}
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}
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MEM_STATIC size_t ZSTD_count(const BYTE* pIn, const BYTE* pMatch, const BYTE* pInLimit)
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{
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const BYTE* const pStart = pIn;
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while ((pIn<pInLimit-(sizeof(size_t)-1)))
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{
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size_t diff = ZSTD_read_ARCH(pMatch) ^ ZSTD_read_ARCH(pIn);
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if (!diff) { pIn+=sizeof(size_t); pMatch+=sizeof(size_t); continue; }
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pIn += ZSTD_NbCommonBytes(diff);
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return (size_t)(pIn - pStart);
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}
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if (MEM_32bits()) if ((pIn<(pInLimit-3)) && (MEM_read32(pMatch) == MEM_read32(pIn))) { pIn+=4; pMatch+=4; }
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if ((pIn<(pInLimit-1)) && (MEM_read16(pMatch) == MEM_read16(pIn))) { pIn+=2; pMatch+=2; }
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if ((pIn<pInLimit) && (*pMatch == *pIn)) pIn++;
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return (size_t)(pIn - pStart);
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}
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static void ZSTD_copy8(void* dst, const void* src) { memcpy(dst, src, 8); }
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#define COPY8(d,s) { ZSTD_copy8(d,s); d+=8; s+=8; }
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/*! ZSTD_wildcopy : custom version of memcpy(), can copy up to 7-8 bytes too many */
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static void ZSTD_wildcopy(void* dst, const void* src, size_t length)
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{
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const BYTE* ip = (const BYTE*)src;
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BYTE* op = (BYTE*)dst;
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BYTE* const oend = op + length;
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do COPY8(op, ip) while (op < oend);
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}
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typedef enum { bt_compressed, bt_raw, bt_rle, bt_end } blockType_t;
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typedef struct
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{
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blockType_t blockType;
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U32 origSize;
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} blockProperties_t;
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size_t ZSTD_noCompressBlock(void* op, size_t maxDstSize, const void* ip, size_t blockSize);
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typedef struct {
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void* buffer;
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U32* offsetStart;
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U32* offset;
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BYTE* offCodeStart;
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BYTE* offCode;
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BYTE* litStart;
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BYTE* lit;
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BYTE* litLengthStart;
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BYTE* litLength;
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BYTE* matchLengthStart;
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BYTE* matchLength;
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BYTE* dumpsStart;
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BYTE* dumps;
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} seqStore_t;
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void ZSTD_resetSeqStore(seqStore_t* ssPtr);
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#define REPCODE_STARTVALUE 4
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#define MLbits 7
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#define LLbits 6
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#define Offbits 5
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#define MaxML ((1<<MLbits) - 1)
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#define MaxLL ((1<<LLbits) - 1)
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#define MaxOff 31
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/** ZSTD_storeSeq
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Store a sequence (literal length, literals, offset code and match length) into seqStore_t
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@offsetCode : distance to match, or 0 == repCode
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@matchCode : matchLength - MINMATCH
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*/
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MEM_STATIC void ZSTD_storeSeq(seqStore_t* seqStorePtr, size_t litLength, const BYTE* literals, size_t offsetCode, size_t matchCode)
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{
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/* copy Literals */
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ZSTD_wildcopy(seqStorePtr->lit, literals, litLength);
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seqStorePtr->lit += litLength;
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/* literal Length */
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if (litLength >= MaxLL)
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{
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*(seqStorePtr->litLength++) = MaxLL;
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if (litLength<255 + MaxLL)
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*(seqStorePtr->dumps++) = (BYTE)(litLength - MaxLL);
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else
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{
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*(seqStorePtr->dumps++) = 255;
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MEM_writeLE32(seqStorePtr->dumps, (U32)litLength); seqStorePtr->dumps += 3;
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}
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}
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else *(seqStorePtr->litLength++) = (BYTE)litLength;
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/* match offset */
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*(seqStorePtr->offset++) = (U32)offsetCode;
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/* match Length */
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if (matchCode >= MaxML)
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{
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*(seqStorePtr->matchLength++) = MaxML;
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if (matchCode < 255+MaxML)
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*(seqStorePtr->dumps++) = (BYTE)(matchCode - MaxML);
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else
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{
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*(seqStorePtr->dumps++) = 255;
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MEM_writeLE32(seqStorePtr->dumps, (U32)matchCode); seqStorePtr->dumps += 3;
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}
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}
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else *(seqStorePtr->matchLength++) = (BYTE)matchCode;
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}
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size_t ZSTD_compressSequences(BYTE* dst, size_t maxDstSize, const seqStore_t* seqStorePtr, size_t srcSize);
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#if defined (__cplusplus)
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}
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#endif
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