module/zstd/lib/decompress/zstd_decompress_internal.h

   1 /*
   2  * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
   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"   /* ZSTD_seqSymbol */
  24
  25
  26
  27 /*-*******************************************************
  28  *  Constants
  29  *********************************************************/
  30 static 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 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 const U32 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 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 typedef struct {
  77     ZSTD_seqSymbol LLTable[SEQSYMBOL_TABLE_SIZE(LLFSELog)];    /* Note : Space reserved for FSE Tables */
  78     ZSTD_seqSymbol OFTable[SEQSYMBOL_TABLE_SIZE(OffFSELog)];   /* is also used as temporary workspace while building hufTable during DDict creation */
  79     ZSTD_seqSymbol MLTable[SEQSYMBOL_TABLE_SIZE(MLFSELog)];    /* and therefore must be at least HUF_DECOMPRESS_WORKSPACE_SIZE large */
  80     HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)];  /* can accommodate HUF_decompress4X */
  81     U32 rep[ZSTD_REP_NUM];
  82 } ZSTD_entropyDTables_t;
  83
  84 typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
  85                ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
  86                ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
  87                ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
  88
  89 typedef enum { zdss_init=0, zdss_loadHeader,
  90                zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
  91
  92 typedef enum {
  93     ZSTD_use_indefinitely = -1,  /* Use the dictionary indefinitely */
  94     ZSTD_dont_use = 0,           /* Do not use the dictionary (if one exists free it) */
  95     ZSTD_use_once = 1            /* Use the dictionary once and set to ZSTD_dont_use */
  96 } ZSTD_dictUses_e;
  97
  98 typedef enum {
  99     ZSTD_obm_buffered = 0,  /* Buffer the output */
 100     ZSTD_obm_stable = 1     /* ZSTD_outBuffer is stable */
 101 } ZSTD_outBufferMode_e;
 102
 103 struct ZSTD_DCtx_s
 104 {
 105     const ZSTD_seqSymbol* LLTptr;
 106     const ZSTD_seqSymbol* MLTptr;
 107     const ZSTD_seqSymbol* OFTptr;
 108     const HUF_DTable* HUFptr;
 109     ZSTD_entropyDTables_t entropy;
 110     U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32];   /* space needed when building huffman tables */
 111     const void* previousDstEnd;   /* detect continuity */
 112     const void* prefixStart;      /* start of current segment */
 113     const void* virtualStart;     /* virtual start of previous segment if it was just before current one */
 114     const void* dictEnd;          /* end of previous segment */
 115     size_t expected;
 116     ZSTD_frameHeader fParams;
 117     U64 decodedSize;
 118     blockType_e bType;            /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
 119     ZSTD_dStage stage;
 120     U32 litEntropy;
 121     U32 fseEntropy;
 122     XXH64_state_t xxhState;
 123     size_t headerSize;
 124     ZSTD_format_e format;
 125     const BYTE* litPtr;
 126     ZSTD_customMem customMem;
 127     size_t litSize;
 128     size_t rleSize;
 129     size_t staticSize;
 130     int bmi2;                     /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
 131
 132     /* dictionary */
 133     ZSTD_DDict* ddictLocal;
 134     const ZSTD_DDict* ddict;     /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
 135     U32 dictID;
 136     int ddictIsCold;             /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
 137     ZSTD_dictUses_e dictUses;
 138
 139     /* streaming */
 140     ZSTD_dStreamStage streamStage;
 141     char*  inBuff;
 142     size_t inBuffSize;
 143     size_t inPos;
 144     size_t maxWindowSize;
 145     char*  outBuff;
 146     size_t outBuffSize;
 147     size_t outStart;
 148     size_t outEnd;
 149     size_t lhSize;
 150     void* legacyContext;
 151     U32 previousLegacyVersion;
 152     U32 legacyVersion;
 153     U32 hostageByte;
 154     int noForwardProgress;
 155     ZSTD_outBufferMode_e outBufferMode;
 156     ZSTD_outBuffer expectedOutBuffer;
 157
 158     /* workspace */
 159     BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH];
 160     BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
 161
 162     size_t oversizedDuration;
 163
 164 #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
 165     void const* dictContentBeginForFuzzing;
 166     void const* dictContentEndForFuzzing;
 167 #endif
 168 };  /* typedef'd to ZSTD_DCtx within "zstd.h" */
 169
 170
 171 /*-*******************************************************
 172  *  Shared internal functions
 173  *********************************************************/
 174
 175 /*! ZSTD_loadDEntropy() :
 176  *  dict : must point at beginning of a valid zstd dictionary.
 177  * @return : size of dictionary header (size of magic number + dict ID + entropy tables) */
 178 size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
 179                    const void* const dict, size_t const dictSize);
 180
 181 /*! ZSTD_checkContinuity() :
 182  *  check if next `dst` follows previous position, where decompression ended.
 183  *  If yes, do nothing (continue on current segment).
 184  *  If not, classify previous segment as "external dictionary", and start a new segment.
 185  *  This function cannot fail. */
 186 void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst);
 187
 188
 189 #endif /* ZSTD_DECOMPRESS_INTERNAL_H */