1 /* 2 * Copyright (c) Meta Platforms, Inc. and affiliates. 3 * All rights reserved. 4 * 5 * This source code is licensed under both the BSD-style license (found in the 6 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 7 * in the COPYING file in the root directory of this source tree). 8 * You may select, at your option, one of the above-listed licenses. 9 */ 10 11 12 /* zstd_decompress_internal: 13 * objects and definitions shared within lib/decompress modules */ 14 15 #ifndef ZSTD_DECOMPRESS_INTERNAL_H 16 #define ZSTD_DECOMPRESS_INTERNAL_H 17 18 19 /*-******************************************************* 20 * Dependencies 21 *********************************************************/ 22 #include "../common/mem.h" /* BYTE, U16, U32 */ 23 #include "../common/zstd_internal.h" /* constants : MaxLL, MaxML, MaxOff, LLFSELog, etc. */ 24 25 26 27 /*-******************************************************* 28 * Constants 29 *********************************************************/ 30 static UNUSED_ATTR const U32 LL_base[MaxLL+1] = { 31 0, 1, 2, 3, 4, 5, 6, 7, 32 8, 9, 10, 11, 12, 13, 14, 15, 33 16, 18, 20, 22, 24, 28, 32, 40, 34 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 35 0x2000, 0x4000, 0x8000, 0x10000 }; 36 37 static UNUSED_ATTR const U32 OF_base[MaxOff+1] = { 38 0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D, 39 0xFD, 0x1FD, 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD, 40 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 41 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD }; 42 43 static UNUSED_ATTR const U8 OF_bits[MaxOff+1] = { 44 0, 1, 2, 3, 4, 5, 6, 7, 45 8, 9, 10, 11, 12, 13, 14, 15, 46 16, 17, 18, 19, 20, 21, 22, 23, 47 24, 25, 26, 27, 28, 29, 30, 31 }; 48 49 static UNUSED_ATTR const U32 ML_base[MaxML+1] = { 50 3, 4, 5, 6, 7, 8, 9, 10, 51 11, 12, 13, 14, 15, 16, 17, 18, 52 19, 20, 21, 22, 23, 24, 25, 26, 53 27, 28, 29, 30, 31, 32, 33, 34, 54 35, 37, 39, 41, 43, 47, 51, 59, 55 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 56 0x1003, 0x2003, 0x4003, 0x8003, 0x10003 }; 57 58 59 /*-******************************************************* 60 * Decompression types 61 *********************************************************/ 62 typedef struct { 63 U32 fastMode; 64 U32 tableLog; 65 } ZSTD_seqSymbol_header; 66 67 typedef struct { 68 U16 nextState; 69 BYTE nbAdditionalBits; 70 BYTE nbBits; 71 U32 baseValue; 72 } ZSTD_seqSymbol; 73 74 #define SEQSYMBOL_TABLE_SIZE(log) (1 + (1 << (log))) 75 76 #define ZSTD_BUILD_FSE_TABLE_WKSP_SIZE (sizeof(S16) * (MaxSeq + 1) + (1u << MaxFSELog) + sizeof(U64)) 77 #define ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32 ((ZSTD_BUILD_FSE_TABLE_WKSP_SIZE + sizeof(U32) - 1) / sizeof(U32)) 78 #define ZSTD_HUFFDTABLE_CAPACITY_LOG 12 79 80 typedef struct { 81 ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)]; /* Note : Space reserved for FSE Tables */ 82 ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)]; /* is also used as temporary workspace while building hufTable during DDict creation */ 83 ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)]; /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */ 84 HUF_DTable hufTable[HUF_DTABLE_SIZE(ZSTD_HUFFDTABLE_CAPACITY_LOG)]; /* can accommodate HUF_decompress4X */ 85 U32 rep[ZSTD_REP_NUM]; 86 U32 workspace[ZSTD_BUILD_FSE_TABLE_WKSP_SIZE_U32]; 87 } ZSTD_entropyDTables_t; 88 89 typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader, 90 ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock, 91 ZSTDds_decompressLastBlock, ZSTDds_checkChecksum, 92 ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage; 93 94 typedef enum { zdss_init=0, zdss_loadHeader, 95 zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage; 96 97 typedef enum { 98 ZSTD_use_indefinitely = -1, /* Use the dictionary indefinitely */ 99 ZSTD_dont_use = 0, /* Do not use the dictionary (if one exists free it) */ 100 ZSTD_use_once = 1 /* Use the dictionary once and set to ZSTD_dont_use */ 101 } ZSTD_dictUses_e; 102 103 /* Hashset for storing references to multiple ZSTD_DDict within ZSTD_DCtx */ 104 typedef struct { 105 const ZSTD_DDict** ddictPtrTable; 106 size_t ddictPtrTableSize; 107 size_t ddictPtrCount; 108 } ZSTD_DDictHashSet; 109 110 #ifndef ZSTD_DECODER_INTERNAL_BUFFER 111 # define ZSTD_DECODER_INTERNAL_BUFFER (1 << 16) 112 #endif 113 114 #define ZSTD_LBMIN 64 115 #define ZSTD_LBMAX (128 << 10) 116 117 /* extra buffer, compensates when dst is not large enough to store litBuffer */ 118 #define ZSTD_LITBUFFEREXTRASIZE BOUNDED(ZSTD_LBMIN, ZSTD_DECODER_INTERNAL_BUFFER, ZSTD_LBMAX) 119 120 typedef enum { 121 ZSTD_not_in_dst = 0, /* Stored entirely within litExtraBuffer */ 122 ZSTD_in_dst = 1, /* Stored entirely within dst (in memory after current output write) */ 123 ZSTD_split = 2 /* Split between litExtraBuffer and dst */ 124 } ZSTD_litLocation_e; 125 126 struct ZSTD_DCtx_s 127 { 128 const ZSTD_seqSymbol* LLTptr; 129 const ZSTD_seqSymbol* MLTptr; 130 const ZSTD_seqSymbol* OFTptr; 131 const HUF_DTable* HUFptr; 132 ZSTD_entropyDTables_t entropy; 133 U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */ 134 const void* previousDstEnd; /* detect continuity */ 135 const void* prefixStart; /* start of current segment */ 136 const void* virtualStart; /* virtual start of previous segment if it was just before current one */ 137 const void* dictEnd; /* end of previous segment */ 138 size_t expected; 139 ZSTD_frameHeader fParams; 140 U64 processedCSize; 141 U64 decodedSize; 142 blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */ 143 ZSTD_dStage stage; 144 U32 litEntropy; 145 U32 fseEntropy; 146 XXH64_state_t xxhState; 147 size_t headerSize; 148 ZSTD_format_e format; 149 ZSTD_forceIgnoreChecksum_e forceIgnoreChecksum; /* User specified: if == 1, will ignore checksums in compressed frame. Default == 0 */ 150 U32 validateChecksum; /* if == 1, will validate checksum. Is == 1 if (fParams.checksumFlag == 1) and (forceIgnoreChecksum == 0). */ 151 const BYTE* litPtr; 152 ZSTD_customMem customMem; 153 size_t litSize; 154 size_t rleSize; 155 size_t staticSize; 156 int isFrameDecompression; 157 #if DYNAMIC_BMI2 != 0 158 int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */ 159 #endif 160 161 /* dictionary */ 162 ZSTD_DDict* ddictLocal; 163 const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */ 164 U32 dictID; 165 int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */ 166 ZSTD_dictUses_e dictUses; 167 ZSTD_DDictHashSet* ddictSet; /* Hash set for multiple ddicts */ 168 ZSTD_refMultipleDDicts_e refMultipleDDicts; /* User specified: if == 1, will allow references to multiple DDicts. Default == 0 (disabled) */ 169 int disableHufAsm; 170 int maxBlockSizeParam; 171 172 /* streaming */ 173 ZSTD_dStreamStage streamStage; 174 char* inBuff; 175 size_t inBuffSize; 176 size_t inPos; 177 size_t maxWindowSize; 178 char* outBuff; 179 size_t outBuffSize; 180 size_t outStart; 181 size_t outEnd; 182 size_t lhSize; 183 #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) 184 void* legacyContext; 185 U32 previousLegacyVersion; 186 U32 legacyVersion; 187 #endif 188 U32 hostageByte; 189 int noForwardProgress; 190 ZSTD_bufferMode_e outBufferMode; 191 ZSTD_outBuffer expectedOutBuffer; 192 193 /* workspace */ 194 BYTE* litBuffer; 195 const BYTE* litBufferEnd; 196 ZSTD_litLocation_e litBufferLocation; 197 BYTE litExtraBuffer[ZSTD_LITBUFFEREXTRASIZE + WILDCOPY_OVERLENGTH]; /* literal buffer can be split between storage within dst and within this scratch buffer */ 198 BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX]; 199 200 size_t oversizedDuration; 201 202 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION 203 void const* dictContentBeginForFuzzing; 204 void const* dictContentEndForFuzzing; 205 #endif 206 207 /* Tracing */ 208 #if ZSTD_TRACE 209 ZSTD_TraceCtx traceCtx; 210 #endif 211 }; /* typedef'd to ZSTD_DCtx within "zstd.h" */ 212 213 MEM_STATIC int ZSTD_DCtx_get_bmi2(const struct ZSTD_DCtx_s *dctx) { 214 #if DYNAMIC_BMI2 != 0 215 return dctx->bmi2; 216 #else 217 (void)dctx; 218 return 0; 219 #endif 220 } 221 222 /*-******************************************************* 223 * Shared internal functions 224 *********************************************************/ 225 226 /*! ZSTD_loadDEntropy() : 227 * dict : must point at beginning of a valid zstd dictionary. 228 * @return : size of dictionary header (size of magic number + dict ID + entropy tables) */ 229 size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy, 230 const void* const dict, size_t const dictSize); 231 232 /*! ZSTD_checkContinuity() : 233 * check if next `dst` follows previous position, where decompression ended. 234 * If yes, do nothing (continue on current segment). 235 * If not, classify previous segment as "external dictionary", and start a new segment. 236 * This function cannot fail. */ 237 void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize); 238 239 240 #endif /* ZSTD_DECOMPRESS_INTERNAL_H */ 241
Indexes created Tue Feb 24 08:35:24 UTC 2026