1 // SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0-only 2 /* 3 * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. 4 * All rights reserved. 5 * 6 * This source code is licensed under both the BSD-style license (found in the 7 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 8 * in the COPYING file in the root directory of this source tree). 9 * You may select, at your option, one of the above-listed licenses. 10 */ 11 12 13 /* zstd_decompress_internal: 14 * objects and definitions shared within lib/decompress modules */ 15 16 #ifndef ZSTD_DECOMPRESS_INTERNAL_H 17 #define ZSTD_DECOMPRESS_INTERNAL_H 18 19 20 /*-******************************************************* 21 * Dependencies 22 *********************************************************/ 23 #include "../common/mem.h" /* BYTE, U16, U32 */ 24 #include "../common/zstd_internal.h" /* ZSTD_seqSymbol */ 25 26 27 28 /*-******************************************************* 29 * Constants 30 *********************************************************/ 31 static const U32 LL_base[MaxLL+1] = { 32 0, 1, 2, 3, 4, 5, 6, 7, 33 8, 9, 10, 11, 12, 13, 14, 15, 34 16, 18, 20, 22, 24, 28, 32, 40, 35 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 36 0x2000, 0x4000, 0x8000, 0x10000 }; 37 38 static const U32 OF_base[MaxOff+1] = { 39 0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D, 40 0xFD, 0x1FD, 0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD, 41 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD, 0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 42 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD, 0x1FFFFFFD, 0x3FFFFFFD, 0x7FFFFFFD }; 43 44 static const U32 OF_bits[MaxOff+1] = { 45 0, 1, 2, 3, 4, 5, 6, 7, 46 8, 9, 10, 11, 12, 13, 14, 15, 47 16, 17, 18, 19, 20, 21, 22, 23, 48 24, 25, 26, 27, 28, 29, 30, 31 }; 49 50 static const U32 ML_base[MaxML+1] = { 51 3, 4, 5, 6, 7, 8, 9, 10, 52 11, 12, 13, 14, 15, 16, 17, 18, 53 19, 20, 21, 22, 23, 24, 25, 26, 54 27, 28, 29, 30, 31, 32, 33, 34, 55 35, 37, 39, 41, 43, 47, 51, 59, 56 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 57 0x1003, 0x2003, 0x4003, 0x8003, 0x10003 }; 58 59 60 /*-******************************************************* 61 * Decompression types 62 *********************************************************/ 63 typedef struct { 64 U32 fastMode; 65 U32 tableLog; 66 } ZSTD_seqSymbol_header; 67 68 typedef struct { 69 U16 nextState; 70 BYTE nbAdditionalBits; 71 BYTE nbBits; 72 U32 baseValue; 73 } ZSTD_seqSymbol; 74 75 #define SEQSYMBOL_TABLE_SIZE(log) (1 + (1 << (log))) 76 77 typedef struct { 78 ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)]; /* Note : Space reserved for FSE Tables */ 79 ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)]; /* is also used as temporary workspace while building hufTable during DDict creation */ 80 ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)]; /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */ 81 HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate HUF_decompress4X */ 82 U32 rep[ZSTD_REP_NUM]; 83 } ZSTD_entropyDTables_t; 84 85 typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader, 86 ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock, 87 ZSTDds_decompressLastBlock, ZSTDds_checkChecksum, 88 ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage; 89 90 typedef enum { zdss_init=0, zdss_loadHeader, 91 zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage; 92 93 typedef enum { 94 ZSTD_use_indefinitely = -1, /* Use the dictionary indefinitely */ 95 ZSTD_dont_use = 0, /* Do not use the dictionary (if one exists free it) */ 96 ZSTD_use_once = 1 /* Use the dictionary once and set to ZSTD_dont_use */ 97 } ZSTD_dictUses_e; 98 99 typedef enum { 100 ZSTD_obm_buffered = 0, /* Buffer the output */ 101 ZSTD_obm_stable = 1 /* ZSTD_outBuffer is stable */ 102 } ZSTD_outBufferMode_e; 103 104 struct ZSTD_DCtx_s 105 { 106 const ZSTD_seqSymbol* LLTptr; 107 const ZSTD_seqSymbol* MLTptr; 108 const ZSTD_seqSymbol* OFTptr; 109 const HUF_DTable* HUFptr; 110 ZSTD_entropyDTables_t entropy; 111 U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */ 112 const void* previousDstEnd; /* detect continuity */ 113 const void* prefixStart; /* start of current segment */ 114 const void* virtualStart; /* virtual start of previous segment if it was just before current one */ 115 const void* dictEnd; /* end of previous segment */ 116 size_t expected; 117 ZSTD_frameHeader fParams; 118 U64 decodedSize; 119 blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */ 120 ZSTD_dStage stage; 121 U32 litEntropy; 122 U32 fseEntropy; 123 XXH64_state_t xxhState; 124 size_t headerSize; 125 ZSTD_format_e format; 126 const BYTE* litPtr; 127 ZSTD_customMem customMem; 128 size_t litSize; 129 size_t rleSize; 130 size_t staticSize; 131 int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */ 132 133 /* dictionary */ 134 ZSTD_DDict* ddictLocal; 135 const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */ 136 U32 dictID; 137 int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */ 138 ZSTD_dictUses_e dictUses; 139 140 /* streaming */ 141 ZSTD_dStreamStage streamStage; 142 char* inBuff; 143 size_t inBuffSize; 144 size_t inPos; 145 size_t maxWindowSize; 146 char* outBuff; 147 size_t outBuffSize; 148 size_t outStart; 149 size_t outEnd; 150 size_t lhSize; 151 void* legacyContext; 152 U32 previousLegacyVersion; 153 U32 legacyVersion; 154 U32 hostageByte; 155 int noForwardProgress; 156 ZSTD_outBufferMode_e outBufferMode; 157 ZSTD_outBuffer expectedOutBuffer; 158 159 /* workspace */ 160 BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH]; 161 BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX]; 162 163 size_t oversizedDuration; 164 165 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION 166 void const* dictContentBeginForFuzzing; 167 void const* dictContentEndForFuzzing; 168 #endif 169 }; /* typedef'd to ZSTD_DCtx within "zstd.h" */ 170 171 172 /*-******************************************************* 173 * Shared internal functions 174 *********************************************************/ 175 176 /*! ZSTD_loadDEntropy() : 177 * dict : must point at beginning of a valid zstd dictionary. 178 * @return : size of dictionary header (size of magic number + dict ID + entropy tables) */ 179 size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy, 180 const void* const dict, size_t const dictSize); 181 182 /*! ZSTD_checkContinuity() : 183 * check if next `dst` follows previous position, where decompression ended. 184 * If yes, do nothing (continue on current segment). 185 * If not, classify previous segment as "external dictionary", and start a new segment. 186 * This function cannot fail. */ 187 void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst); 188 189 190 #endif /* ZSTD_DECOMPRESS_INTERNAL_H */ 191