/* * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the * LICENSE file in the root directory of this source tree) and the GPLv2 (found * in the COPYING file in the root directory of this source tree). * You may select, at your option, one of the above-listed licenses. */ /* zstd_decompress_internal: * objects and definitions shared within lib/decompress modules */ #ifndef ZSTD_DECOMPRESS_INTERNAL_H #define ZSTD_DECOMPRESS_INTERNAL_H /*-******************************************************* * Dependencies *********************************************************/ #include "mem.h" /* BYTE, U16, U32 */ #include "zstd_internal.h" /* ZSTD_seqSymbol */ /*-******************************************************* * Constants *********************************************************/ static const U32 LL_base[MaxLL+1] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18, 20, 22, 24, 28, 32, 40, 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000 }; static const U32 OF_base[MaxOff+1] = { 0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D, 0xFD, 0x1FD, 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD, 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD }; static const U32 OF_bits[MaxOff+1] = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 }; static const U32 ML_base[MaxML+1] = { 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 39, 41, 43, 47, 51, 59, 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 0x1003, 0x2003, 0x4003, 0x8003, 0x10003 }; /*-******************************************************* * Decompression types *********************************************************/ typedef struct { U32 fastMode; U32 tableLog; } ZSTD_seqSymbol_header; typedef struct { U16 nextState; BYTE nbAdditionalBits; BYTE nbBits; U32 baseValue; } ZSTD_seqSymbol; #define SEQSYMBOL_TABLE_SIZE(log) (1 + (1 << (log))) typedef struct { ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)]; /* Note : Space reserved for FSE Tables */ ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)]; /* is also used as temporary workspace while building hufTable during DDict creation */ ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)]; /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */ HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate HUF_decompress4X */ U32 rep[ZSTD_REP_NUM]; } ZSTD_entropyDTables_t; typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader, ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock, ZSTDds_decompressLastBlock, ZSTDds_checkChecksum, ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage; typedef enum { zdss_init=0, zdss_loadHeader, zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage; typedef enum { ZSTD_use_indefinitely = -1, /* Use the dictionary indefinitely */ ZSTD_dont_use = 0, /* Do not use the dictionary (if one exists free it) */ ZSTD_use_once = 1 /* Use the dictionary once and set to ZSTD_dont_use */ } ZSTD_dictUses_e; struct ZSTD_DCtx_s { const ZSTD_seqSymbol* LLTptr; const ZSTD_seqSymbol* MLTptr; const ZSTD_seqSymbol* OFTptr; const HUF_DTable* HUFptr; ZSTD_entropyDTables_t entropy; U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */ const void* previousDstEnd; /* detect continuity */ const void* prefixStart; /* start of current segment */ const void* virtualStart; /* virtual start of previous segment if it was just before current one */ const void* dictEnd; /* end of previous segment */ size_t expected; ZSTD_frameHeader fParams; U64 decodedSize; blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */ ZSTD_dStage stage; U32 litEntropy; U32 fseEntropy; XXH64_state_t xxhState; size_t headerSize; ZSTD_format_e format; const BYTE* litPtr; ZSTD_customMem customMem; size_t litSize; size_t rleSize; size_t staticSize; int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */ /* dictionary */ ZSTD_DDict* ddictLocal; const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */ U32 dictID; int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */ ZSTD_dictUses_e dictUses; /* streaming */ ZSTD_dStreamStage streamStage; char* inBuff; size_t inBuffSize; size_t inPos; size_t maxWindowSize; char* outBuff; size_t outBuffSize; size_t outStart; size_t outEnd; size_t lhSize; void* legacyContext; U32 previousLegacyVersion; U32 legacyVersion; U32 hostageByte; int noForwardProgress; /* workspace */ BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH]; BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX]; }; /* typedef'd to ZSTD_DCtx within "zstd.h" */ /*-******************************************************* * Shared internal functions *********************************************************/ /*! ZSTD_loadDEntropy() : * dict : must point at beginning of a valid zstd dictionary. * @return : size of dictionary header (size of magic number + dict ID + entropy tables) */ size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy, const void* const dict, size_t const dictSize); /*! ZSTD_checkContinuity() : * check if next `dst` follows previous position, where decompression ended. * If yes, do nothing (continue on current segment). * If not, classify previous segment as "external dictionary", and start a new segment. * This function cannot fail. */ void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst); #endif /* ZSTD_DECOMPRESS_INTERNAL_H */