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