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Scott Baker8487c5d2019-10-18 12:49:46 -07001/*
2 * Copyright (c) 2016-present, 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 "mem.h" /* BYTE, U16, U32 */
23#include "zstd_internal.h" /* ZSTD_seqSymbol */
24
25
26
27/*-*******************************************************
28 * Constants
29 *********************************************************/
30static 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
37static 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
43static 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
49static 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
76typedef 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
84typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
85 ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
86 ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
87 ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
88
89typedef enum { zdss_init=0, zdss_loadHeader,
90 zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
91
92typedef 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
98struct ZSTD_DCtx_s
99{
100 const ZSTD_seqSymbol* LLTptr;
101 const ZSTD_seqSymbol* MLTptr;
102 const ZSTD_seqSymbol* OFTptr;
103 const HUF_DTable* HUFptr;
104 ZSTD_entropyDTables_t entropy;
105 U32 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32]; /* space needed when building huffman tables */
106 const void* previousDstEnd; /* detect continuity */
107 const void* prefixStart; /* start of current segment */
108 const void* virtualStart; /* virtual start of previous segment if it was just before current one */
109 const void* dictEnd; /* end of previous segment */
110 size_t expected;
111 ZSTD_frameHeader fParams;
112 U64 decodedSize;
113 blockType_e bType; /* used in ZSTD_decompressContinue(), store blockType between block header decoding and block decompression stages */
114 ZSTD_dStage stage;
115 U32 litEntropy;
116 U32 fseEntropy;
117 XXH64_state_t xxhState;
118 size_t headerSize;
119 ZSTD_format_e format;
120 const BYTE* litPtr;
121 ZSTD_customMem customMem;
122 size_t litSize;
123 size_t rleSize;
124 size_t staticSize;
125 int bmi2; /* == 1 if the CPU supports BMI2 and 0 otherwise. CPU support is determined dynamically once per context lifetime. */
126
127 /* dictionary */
128 ZSTD_DDict* ddictLocal;
129 const ZSTD_DDict* ddict; /* set by ZSTD_initDStream_usingDDict(), or ZSTD_DCtx_refDDict() */
130 U32 dictID;
131 int ddictIsCold; /* if == 1 : dictionary is "new" for working context, and presumed "cold" (not in cpu cache) */
132 ZSTD_dictUses_e dictUses;
133
134 /* streaming */
135 ZSTD_dStreamStage streamStage;
136 char* inBuff;
137 size_t inBuffSize;
138 size_t inPos;
139 size_t maxWindowSize;
140 char* outBuff;
141 size_t outBuffSize;
142 size_t outStart;
143 size_t outEnd;
144 size_t lhSize;
145 void* legacyContext;
146 U32 previousLegacyVersion;
147 U32 legacyVersion;
148 U32 hostageByte;
149 int noForwardProgress;
150
151 /* workspace */
152 BYTE litBuffer[ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH];
153 BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
154}; /* typedef'd to ZSTD_DCtx within "zstd.h" */
155
156
157/*-*******************************************************
158 * Shared internal functions
159 *********************************************************/
160
161/*! ZSTD_loadDEntropy() :
162 * dict : must point at beginning of a valid zstd dictionary.
163 * @return : size of entropy tables read */
164size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy,
165 const void* const dict, size_t const dictSize);
166
167/*! ZSTD_checkContinuity() :
168 * check if next `dst` follows previous position, where decompression ended.
169 * If yes, do nothing (continue on current segment).
170 * If not, classify previous segment as "external dictionary", and start a new segment.
171 * This function cannot fail. */
172void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst);
173
174
175#endif /* ZSTD_DECOMPRESS_INTERNAL_H */