124 lines
4.5 KiB
C
124 lines
4.5 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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* Decompression types
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*********************************************************/
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typedef struct {
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U16 nextState;
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BYTE nbAdditionalBits;
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BYTE nbBits;
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U32 baseValue;
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} ZSTD_seqSymbol;
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#define SEQSYMBOL_TABLE_SIZE(log) (1 + (1 << (log)))
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typedef struct {
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ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)]; /* Note : Space reserved for FSE Tables */
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ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)]; /* is also used as temporary workspace while building hufTable during DDict creation */
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ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)]; /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */
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HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate HUF_decompress4X */
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U32 rep[ZSTD_REP_NUM];
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} ZSTD_entropyDTables_t;
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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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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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/* 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_loadDEntropy() :
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* dict : must point at beginning of a valid zstd dictionary.
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* @return : size of entropy tables read */
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size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
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const void* const dict, size_t const dictSize);
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#endif /* ZSTD_DECOMPRESS_INTERNAL_H */
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