1 /* SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause */ 2 /* ****************************************************************** 3 * huff0 huffman codec, 4 * part of Finite State Entropy library 5 * Copyright (c) Meta Platforms, Inc. and affiliates. 6 * 7 * You can contact the author at : 8 * - Source repository : https://github.com/Cyan4973/FiniteStateEntropy 9 * 10 * This source code is licensed under both the BSD-style license (found in the 11 * LICENSE file in the root directory of this source tree) and the GPLv2 (found 12 * in the COPYING file in the root directory of this source tree). 13 * You may select, at your option, one of the above-listed licenses. 14 ****************************************************************** */ 15 16 #ifndef HUF_H_298734234 17 #define HUF_H_298734234 18 19 /* *** Dependencies *** */ 20 #include "zstd_deps.h" /* size_t */ 21 #include "mem.h" /* U32 */ 22 #define FSE_STATIC_LINKING_ONLY 23 #include "fse.h" 24 25 /* *** Tool functions *** */ 26 #define HUF_BLOCKSIZE_MAX (128 * 1024) /*< maximum input size for a single block compressed with HUF_compress */ 27 size_t HUF_compressBound(size_t size); /*< maximum compressed size (worst case) */ 28 29 /* Error Management */ 30 unsigned HUF_isError(size_t code); /*< tells if a return value is an error code */ 31 const char* HUF_getErrorName(size_t code); /*< provides error code string (useful for debugging) */ 32 33 34 #define HUF_WORKSPACE_SIZE ((8 << 10) + 512 /* sorting scratch space */) 35 #define HUF_WORKSPACE_SIZE_U64 (HUF_WORKSPACE_SIZE / sizeof(U64)) 36 37 /* *** Constants *** */ 38 #define HUF_TABLELOG_MAX 12 /* max runtime value of tableLog (due to static allocation); can be modified up to HUF_TABLELOG_ABSOLUTEMAX */ 39 #define HUF_TABLELOG_DEFAULT 11 /* default tableLog value when none specified */ 40 #define HUF_SYMBOLVALUE_MAX 255 41 42 #define HUF_TABLELOG_ABSOLUTEMAX 12 /* absolute limit of HUF_MAX_TABLELOG. Beyond that value, code does not work */ 43 #if (HUF_TABLELOG_MAX > HUF_TABLELOG_ABSOLUTEMAX) 44 # error "HUF_TABLELOG_MAX is too large !" 45 #endif 46 47 48 /* **************************************** 49 * Static allocation 50 ******************************************/ 51 /* HUF buffer bounds */ 52 #define HUF_CTABLEBOUND 129 53 #define HUF_BLOCKBOUND(size) (size + (size>>8) + 8) /* only true when incompressible is pre-filtered with fast heuristic */ 54 #define HUF_COMPRESSBOUND(size) (HUF_CTABLEBOUND + HUF_BLOCKBOUND(size)) /* Macro version, useful for static allocation */ 55 56 /* static allocation of HUF's Compression Table */ 57 /* this is a private definition, just exposed for allocation and strict aliasing purpose. never EVER access its members directly */ 58 typedef size_t HUF_CElt; /* consider it an incomplete type */ 59 #define HUF_CTABLE_SIZE_ST(maxSymbolValue) ((maxSymbolValue)+2) /* Use tables of size_t, for proper alignment */ 60 #define HUF_CTABLE_SIZE(maxSymbolValue) (HUF_CTABLE_SIZE_ST(maxSymbolValue) * sizeof(size_t)) 61 #define HUF_CREATE_STATIC_CTABLE(name, maxSymbolValue) \ 62 HUF_CElt name[HUF_CTABLE_SIZE_ST(maxSymbolValue)] /* no final ; */ 63 64 /* static allocation of HUF's DTable */ 65 typedef U32 HUF_DTable; 66 #define HUF_DTABLE_SIZE(maxTableLog) (1 + (1<<(maxTableLog))) 67 #define HUF_CREATE_STATIC_DTABLEX1(DTable, maxTableLog) \ 68 HUF_DTable DTable[HUF_DTABLE_SIZE((maxTableLog)-1)] = { ((U32)((maxTableLog)-1) * 0x01000001) } 69 #define HUF_CREATE_STATIC_DTABLEX2(DTable, maxTableLog) \ 70 HUF_DTable DTable[HUF_DTABLE_SIZE(maxTableLog)] = { ((U32)(maxTableLog) * 0x01000001) } 71 72 73 /* **************************************** 74 * Advanced decompression functions 75 ******************************************/ 76 77 /* 78 * Huffman flags bitset. 79 * For all flags, 0 is the default value. 80 */ 81 typedef enum { 82 /* 83 * If compiled with DYNAMIC_BMI2: Set flag only if the CPU supports BMI2 at runtime. 84 * Otherwise: Ignored. 85 */ 86 HUF_flags_bmi2 = (1 << 0), 87 /* 88 * If set: Test possible table depths to find the one that produces the smallest header + encoded size. 89 * If unset: Use heuristic to find the table depth. 90 */ 91 HUF_flags_optimalDepth = (1 << 1), 92 /* 93 * If set: If the previous table can encode the input, always reuse the previous table. 94 * If unset: If the previous table can encode the input, reuse the previous table if it results in a smaller output. 95 */ 96 HUF_flags_preferRepeat = (1 << 2), 97 /* 98 * If set: Sample the input and check if the sample is uncompressible, if it is then don't attempt to compress. 99 * If unset: Always histogram the entire input. 100 */ 101 HUF_flags_suspectUncompressible = (1 << 3), 102 /* 103 * If set: Don't use assembly implementations 104 * If unset: Allow using assembly implementations 105 */ 106 HUF_flags_disableAsm = (1 << 4), 107 /* 108 * If set: Don't use the fast decoding loop, always use the fallback decoding loop. 109 * If unset: Use the fast decoding loop when possible. 110 */ 111 HUF_flags_disableFast = (1 << 5) 112 } HUF_flags_e; 113 114 115 /* **************************************** 116 * HUF detailed API 117 * ****************************************/ 118 #define HUF_OPTIMAL_DEPTH_THRESHOLD ZSTD_btultra 119 120 /*! HUF_compress() does the following: 121 * 1. count symbol occurrence from source[] into table count[] using FSE_count() (exposed within "fse.h") 122 * 2. (optional) refine tableLog using HUF_optimalTableLog() 123 * 3. build Huffman table from count using HUF_buildCTable() 124 * 4. save Huffman table to memory buffer using HUF_writeCTable() 125 * 5. encode the data stream using HUF_compress4X_usingCTable() 126 * 127 * The following API allows targeting specific sub-functions for advanced tasks. 128 * For example, it's possible to compress several blocks using the same 'CTable', 129 * or to save and regenerate 'CTable' using external methods. 130 */ 131 unsigned HUF_minTableLog(unsigned symbolCardinality); 132 unsigned HUF_cardinality(const unsigned* count, unsigned maxSymbolValue); 133 unsigned HUF_optimalTableLog(unsigned maxTableLog, size_t srcSize, unsigned maxSymbolValue, void* workSpace, 134 size_t wkspSize, HUF_CElt* table, const unsigned* count, int flags); /* table is used as scratch space for building and testing tables, not a return value */ 135 size_t HUF_writeCTable_wksp(void* dst, size_t maxDstSize, const HUF_CElt* CTable, unsigned maxSymbolValue, unsigned huffLog, void* workspace, size_t workspaceSize); 136 size_t HUF_compress4X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int flags); 137 size_t HUF_estimateCompressedSize(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue); 138 int HUF_validateCTable(const HUF_CElt* CTable, const unsigned* count, unsigned maxSymbolValue); 139 140 typedef enum { 141 HUF_repeat_none, /*< Cannot use the previous table */ 142 HUF_repeat_check, /*< Can use the previous table but it must be checked. Note : The previous table must have been constructed by HUF_compress{1, 4}X_repeat */ 143 HUF_repeat_valid /*< Can use the previous table and it is assumed to be valid */ 144 } HUF_repeat; 145 146 /* HUF_compress4X_repeat() : 147 * Same as HUF_compress4X_wksp(), but considers using hufTable if *repeat != HUF_repeat_none. 148 * If it uses hufTable it does not modify hufTable or repeat. 149 * If it doesn't, it sets *repeat = HUF_repeat_none, and it sets hufTable to the table used. 150 * If preferRepeat then the old table will always be used if valid. 151 * If suspectUncompressible then some sampling checks will be run to potentially skip huffman coding */ 152 size_t HUF_compress4X_repeat(void* dst, size_t dstSize, 153 const void* src, size_t srcSize, 154 unsigned maxSymbolValue, unsigned tableLog, 155 void* workSpace, size_t wkspSize, /*< `workSpace` must be aligned on 4-bytes boundaries, `wkspSize` must be >= HUF_WORKSPACE_SIZE */ 156 HUF_CElt* hufTable, HUF_repeat* repeat, int flags); 157 158 /* HUF_buildCTable_wksp() : 159 * Same as HUF_buildCTable(), but using externally allocated scratch buffer. 160 * `workSpace` must be aligned on 4-bytes boundaries, and its size must be >= HUF_CTABLE_WORKSPACE_SIZE. 161 */ 162 #define HUF_CTABLE_WORKSPACE_SIZE_U32 ((4 * (HUF_SYMBOLVALUE_MAX + 1)) + 192) 163 #define HUF_CTABLE_WORKSPACE_SIZE (HUF_CTABLE_WORKSPACE_SIZE_U32 * sizeof(unsigned)) 164 size_t HUF_buildCTable_wksp (HUF_CElt* tree, 165 const unsigned* count, U32 maxSymbolValue, U32 maxNbBits, 166 void* workSpace, size_t wkspSize); 167 168 /*! HUF_readStats() : 169 * Read compact Huffman tree, saved by HUF_writeCTable(). 170 * `huffWeight` is destination buffer. 171 * @return : size read from `src` , or an error Code . 172 * Note : Needed by HUF_readCTable() and HUF_readDTableXn() . */ 173 size_t HUF_readStats(BYTE* huffWeight, size_t hwSize, 174 U32* rankStats, U32* nbSymbolsPtr, U32* tableLogPtr, 175 const void* src, size_t srcSize); 176 177 /*! HUF_readStats_wksp() : 178 * Same as HUF_readStats() but takes an external workspace which must be 179 * 4-byte aligned and its size must be >= HUF_READ_STATS_WORKSPACE_SIZE. 180 * If the CPU has BMI2 support, pass bmi2=1, otherwise pass bmi2=0. 181 */ 182 #define HUF_READ_STATS_WORKSPACE_SIZE_U32 FSE_DECOMPRESS_WKSP_SIZE_U32(6, HUF_TABLELOG_MAX-1) 183 #define HUF_READ_STATS_WORKSPACE_SIZE (HUF_READ_STATS_WORKSPACE_SIZE_U32 * sizeof(unsigned)) 184 size_t HUF_readStats_wksp(BYTE* huffWeight, size_t hwSize, 185 U32* rankStats, U32* nbSymbolsPtr, U32* tableLogPtr, 186 const void* src, size_t srcSize, 187 void* workspace, size_t wkspSize, 188 int flags); 189 190 /* HUF_readCTable() : 191 * Loading a CTable saved with HUF_writeCTable() */ 192 size_t HUF_readCTable (HUF_CElt* CTable, unsigned* maxSymbolValuePtr, const void* src, size_t srcSize, unsigned *hasZeroWeights); 193 194 /* HUF_getNbBitsFromCTable() : 195 * Read nbBits from CTable symbolTable, for symbol `symbolValue` presumed <= HUF_SYMBOLVALUE_MAX 196 * Note 1 : If symbolValue > HUF_readCTableHeader(symbolTable).maxSymbolValue, returns 0 197 * Note 2 : is not inlined, as HUF_CElt definition is private 198 */ 199 U32 HUF_getNbBitsFromCTable(const HUF_CElt* symbolTable, U32 symbolValue); 200 201 typedef struct { 202 BYTE tableLog; 203 BYTE maxSymbolValue; 204 BYTE unused[sizeof(size_t) - 2]; 205 } HUF_CTableHeader; 206 207 /* HUF_readCTableHeader() : 208 * @returns The header from the CTable specifying the tableLog and the maxSymbolValue. 209 */ 210 HUF_CTableHeader HUF_readCTableHeader(HUF_CElt const* ctable); 211 212 /* 213 * HUF_decompress() does the following: 214 * 1. select the decompression algorithm (X1, X2) based on pre-computed heuristics 215 * 2. build Huffman table from save, using HUF_readDTableX?() 216 * 3. decode 1 or 4 segments in parallel using HUF_decompress?X?_usingDTable() 217 */ 218 219 /* HUF_selectDecoder() : 220 * Tells which decoder is likely to decode faster, 221 * based on a set of pre-computed metrics. 222 * @return : 0==HUF_decompress4X1, 1==HUF_decompress4X2 . 223 * Assumption : 0 < dstSize <= 128 KB */ 224 U32 HUF_selectDecoder (size_t dstSize, size_t cSrcSize); 225 226 /* 227 * The minimum workspace size for the `workSpace` used in 228 * HUF_readDTableX1_wksp() and HUF_readDTableX2_wksp(). 229 * 230 * The space used depends on HUF_TABLELOG_MAX, ranging from ~1500 bytes when 231 * HUF_TABLE_LOG_MAX=12 to ~1850 bytes when HUF_TABLE_LOG_MAX=15. 232 * Buffer overflow errors may potentially occur if code modifications result in 233 * a required workspace size greater than that specified in the following 234 * macro. 235 */ 236 #define HUF_DECOMPRESS_WORKSPACE_SIZE ((2 << 10) + (1 << 9)) 237 #define HUF_DECOMPRESS_WORKSPACE_SIZE_U32 (HUF_DECOMPRESS_WORKSPACE_SIZE / sizeof(U32)) 238 239 240 /* ====================== */ 241 /* single stream variants */ 242 /* ====================== */ 243 244 size_t HUF_compress1X_usingCTable(void* dst, size_t dstSize, const void* src, size_t srcSize, const HUF_CElt* CTable, int flags); 245 /* HUF_compress1X_repeat() : 246 * Same as HUF_compress1X_wksp(), but considers using hufTable if *repeat != HUF_repeat_none. 247 * If it uses hufTable it does not modify hufTable or repeat. 248 * If it doesn't, it sets *repeat = HUF_repeat_none, and it sets hufTable to the table used. 249 * If preferRepeat then the old table will always be used if valid. 250 * If suspectUncompressible then some sampling checks will be run to potentially skip huffman coding */ 251 size_t HUF_compress1X_repeat(void* dst, size_t dstSize, 252 const void* src, size_t srcSize, 253 unsigned maxSymbolValue, unsigned tableLog, 254 void* workSpace, size_t wkspSize, /*< `workSpace` must be aligned on 4-bytes boundaries, `wkspSize` must be >= HUF_WORKSPACE_SIZE */ 255 HUF_CElt* hufTable, HUF_repeat* repeat, int flags); 256 257 size_t HUF_decompress1X_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags); 258 #ifndef HUF_FORCE_DECOMPRESS_X1 259 size_t HUF_decompress1X2_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags); /*< double-symbols decoder */ 260 #endif 261 262 /* BMI2 variants. 263 * If the CPU has BMI2 support, pass bmi2=1, otherwise pass bmi2=0. 264 */ 265 size_t HUF_decompress1X_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int flags); 266 #ifndef HUF_FORCE_DECOMPRESS_X2 267 size_t HUF_decompress1X1_DCtx_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags); 268 #endif 269 size_t HUF_decompress4X_usingDTable(void* dst, size_t maxDstSize, const void* cSrc, size_t cSrcSize, const HUF_DTable* DTable, int flags); 270 size_t HUF_decompress4X_hufOnly_wksp(HUF_DTable* dctx, void* dst, size_t dstSize, const void* cSrc, size_t cSrcSize, void* workSpace, size_t wkspSize, int flags); 271 #ifndef HUF_FORCE_DECOMPRESS_X2 272 size_t HUF_readDTableX1_wksp(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize, int flags); 273 #endif 274 #ifndef HUF_FORCE_DECOMPRESS_X1 275 size_t HUF_readDTableX2_wksp(HUF_DTable* DTable, const void* src, size_t srcSize, void* workSpace, size_t wkspSize, int flags); 276 #endif 277 278 #endif /* HUF_H_298734234 */ 279