2 * Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
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.
12 /* zstd_decompress_internal:
13 * objects and definitions shared within lib/decompress modules */
15 #ifndef ZSTD_DECOMPRESS_INTERNAL_H
16 #define ZSTD_DECOMPRESS_INTERNAL_H
19 /*-*******************************************************
21 *********************************************************/
22 #include "mem.h" /* BYTE, U16, U32 */
23 #include "zstd_internal.h" /* ZSTD_seqSymbol */
27 /*-*******************************************************
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 };
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 };
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 };
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 };
59 /*-*******************************************************
61 *********************************************************/
65 } ZSTD_seqSymbol_header;
69 BYTE nbAdditionalBits;
74 #define SEQSYMBOL_TABLE_SIZE(log) (1 + (1 << (log)))
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;
84 typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
85 ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
86 ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
87 ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
89 typedef enum { zdss_init=0, zdss_loadHeader,
90 zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
94 const ZSTD_seqSymbol* LLTptr;
95 const ZSTD_seqSymbol* MLTptr;
96 const ZSTD_seqSymbol* OFTptr;
97 const HUF_DTable* HUFptr;
98 ZSTD_entropyDTables_t entropy;
99 U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */
100 const void* previousDstEnd; /* detect continuity */
101 const void* prefixStart; /* start of current segment */
102 const void* virtualStart; /* virtual start of previous segment if it was just before current one */
103 const void* dictEnd; /* end of previous segment */
105 ZSTD_frameHeader fParams;
107 blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
111 XXH64_state_t xxhState;
113 ZSTD_format_e format;
115 ZSTD_customMem customMem;
119 int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
122 ZSTD_DDict* ddictLocal;
123 const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
125 int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
128 ZSTD_dStreamStage streamStage;
132 size_t maxWindowSize;
139 U32 previousLegacyVersion;
142 int noForwardProgress;
145 BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH];
146 BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
147 }; /* typedef'd to ZSTD_DCtx within "zstd.h" */
150 /*-*******************************************************
151 * Shared internal functions
152 *********************************************************/
154 /*! ZSTD_loadDEntropy() :
155 * dict : must point at beginning of a valid zstd dictionary.
156 * @return : size of entropy tables read */
157 size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
158 const void* const dict, size_t const dictSize);
160 /*! ZSTD_checkContinuity() :
161 * check if next `dst` follows previous position, where decompression ended.
162 * If yes, do nothing (continue on current segment).
163 * If not, classify previous segment as "external dictionary", and start a new segment.
164 * This function cannot fail. */
165 void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst);
168 #endif /* ZSTD_DECOMPRESS_INTERNAL_H */