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// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0-only
/*
* 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 "../common/mem.h" /* BYTE, U16, U32 */
#include "../common/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;
typedef enum {
ZSTD_obm_buffered = 0, /* Buffer the output */
ZSTD_obm_stable = 1 /* ZSTD_outBuffer is stable */
} ZSTD_outBufferMode_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;
ZSTD_outBufferMode_e outBufferMode;
ZSTD_outBuffer expectedOutBuffer;
/* workspace */
BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH];
BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
size_t oversizedDuration;
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
void const* dictContentBeginForFuzzing;
void const* dictContentEndForFuzzing;
#endif
}; /* 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 */
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