| 1 | /* |
| 2 | * Copyright (c) Meta Platforms, Inc. and affiliates. |
| 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 | /* zstd_decompress_block : |
| 12 | * this module takes care of decompressing _compressed_ block */ |
| 13 | |
| 14 | /*-******************************************************* |
| 15 | * Dependencies |
| 16 | *********************************************************/ |
| 17 | #include "../common/zstd_deps.h" /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */ |
| 18 | #include "../common/compiler.h" /* prefetch */ |
| 19 | #include "../common/cpu.h" /* bmi2 */ |
| 20 | #include "../common/mem.h" /* low level memory routines */ |
| 21 | #define FSE_STATIC_LINKING_ONLY |
| 22 | #include "../common/fse.h" |
| 23 | #include "../common/huf.h" |
| 24 | #include "../common/zstd_internal.h" |
| 25 | #include "zstd_decompress_internal.h" /* ZSTD_DCtx */ |
| 26 | #include "zstd_ddict.h" /* ZSTD_DDictDictContent */ |
| 27 | #include "zstd_decompress_block.h" |
| 28 | #include "../common/bits.h" /* ZSTD_highbit32 */ |
| 29 | |
| 30 | /*_******************************************************* |
| 31 | * Macros |
| 32 | **********************************************************/ |
| 33 | |
| 34 | /* These two optional macros force the use one way or another of the two |
| 35 | * ZSTD_decompressSequences implementations. You can't force in both directions |
| 36 | * at the same time. |
| 37 | */ |
| 38 | #if defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \ |
| 39 | defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG) |
| 40 | #error "Cannot force the use of the short and the long ZSTD_decompressSequences variants!" |
| 41 | #endif |
| 42 | |
| 43 | |
| 44 | /*_******************************************************* |
| 45 | * Memory operations |
| 46 | **********************************************************/ |
| 47 | static void ZSTD_copy4(void* dst, const void* src) { ZSTD_memcpy(dst, src, 4); } |
| 48 | |
| 49 | |
| 50 | /*-************************************************************* |
| 51 | * Block decoding |
| 52 | ***************************************************************/ |
| 53 | |
| 54 | /*! ZSTD_getcBlockSize() : |
| 55 | * Provides the size of compressed block from block header `src` */ |
| 56 | size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, |
| 57 | blockProperties_t* bpPtr) |
| 58 | { |
| 59 | RETURN_ERROR_IF(srcSize < ZSTD_blockHeaderSize, srcSize_wrong, ""); |
| 60 | |
| 61 | { U32 const cBlockHeader = MEM_readLE24(src); |
| 62 | U32 const cSize = cBlockHeader >> 3; |
| 63 | bpPtr->lastBlock = cBlockHeader & 1; |
| 64 | bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3); |
| 65 | bpPtr->origSize = cSize; /* only useful for RLE */ |
| 66 | if (bpPtr->blockType == bt_rle) return 1; |
| 67 | RETURN_ERROR_IF(bpPtr->blockType == bt_reserved, corruption_detected, ""); |
| 68 | return cSize; |
| 69 | } |
| 70 | } |
| 71 | |
| 72 | /* Allocate buffer for literals, either overlapping current dst, or split between dst and litExtraBuffer, or stored entirely within litExtraBuffer */ |
| 73 | static void ZSTD_allocateLiteralsBuffer(ZSTD_DCtx* dctx, void* const dst, const size_t dstCapacity, const size_t litSize, |
| 74 | const streaming_operation streaming, const size_t expectedWriteSize, const unsigned splitImmediately) |
| 75 | { |
| 76 | if (streaming == not_streaming && dstCapacity > ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH + litSize + WILDCOPY_OVERLENGTH) |
| 77 | { |
| 78 | /* room for litbuffer to fit without read faulting */ |
| 79 | dctx->litBuffer = (BYTE*)dst + ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH; |
| 80 | dctx->litBufferEnd = dctx->litBuffer + litSize; |
| 81 | dctx->litBufferLocation = ZSTD_in_dst; |
| 82 | } |
| 83 | else if (litSize > ZSTD_LITBUFFEREXTRASIZE) |
| 84 | { |
| 85 | /* won't fit in litExtraBuffer, so it will be split between end of dst and extra buffer */ |
| 86 | if (splitImmediately) { |
| 87 | /* won't fit in litExtraBuffer, so it will be split between end of dst and extra buffer */ |
| 88 | dctx->litBuffer = (BYTE*)dst + expectedWriteSize - litSize + ZSTD_LITBUFFEREXTRASIZE - WILDCOPY_OVERLENGTH; |
| 89 | dctx->litBufferEnd = dctx->litBuffer + litSize - ZSTD_LITBUFFEREXTRASIZE; |
| 90 | } |
| 91 | else { |
| 92 | /* initially this will be stored entirely in dst during huffman decoding, it will partially be shifted to litExtraBuffer after */ |
| 93 | dctx->litBuffer = (BYTE*)dst + expectedWriteSize - litSize; |
| 94 | dctx->litBufferEnd = (BYTE*)dst + expectedWriteSize; |
| 95 | } |
| 96 | dctx->litBufferLocation = ZSTD_split; |
| 97 | } |
| 98 | else |
| 99 | { |
| 100 | /* fits entirely within litExtraBuffer, so no split is necessary */ |
| 101 | dctx->litBuffer = dctx->litExtraBuffer; |
| 102 | dctx->litBufferEnd = dctx->litBuffer + litSize; |
| 103 | dctx->litBufferLocation = ZSTD_not_in_dst; |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | /* Hidden declaration for fullbench */ |
| 108 | size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, |
| 109 | const void* src, size_t srcSize, |
| 110 | void* dst, size_t dstCapacity, const streaming_operation streaming); |
| 111 | /*! ZSTD_decodeLiteralsBlock() : |
| 112 | * Where it is possible to do so without being stomped by the output during decompression, the literals block will be stored |
| 113 | * in the dstBuffer. If there is room to do so, it will be stored in full in the excess dst space after where the current |
| 114 | * block will be output. Otherwise it will be stored at the end of the current dst blockspace, with a small portion being |
| 115 | * stored in dctx->litExtraBuffer to help keep it "ahead" of the current output write. |
| 116 | * |
| 117 | * @return : nb of bytes read from src (< srcSize ) |
| 118 | * note : symbol not declared but exposed for fullbench */ |
| 119 | size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, |
| 120 | const void* src, size_t srcSize, /* note : srcSize < BLOCKSIZE */ |
| 121 | void* dst, size_t dstCapacity, const streaming_operation streaming) |
| 122 | { |
| 123 | DEBUGLOG(5, "ZSTD_decodeLiteralsBlock"); |
| 124 | RETURN_ERROR_IF(srcSize < MIN_CBLOCK_SIZE, corruption_detected, ""); |
| 125 | |
| 126 | { const BYTE* const istart = (const BYTE*) src; |
| 127 | symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3); |
| 128 | |
| 129 | switch(litEncType) |
| 130 | { |
| 131 | case set_repeat: |
| 132 | DEBUGLOG(5, "set_repeat flag : re-using stats from previous compressed literals block"); |
| 133 | RETURN_ERROR_IF(dctx->litEntropy==0, dictionary_corrupted, ""); |
| 134 | ZSTD_FALLTHROUGH; |
| 135 | |
| 136 | case set_compressed: |
| 137 | RETURN_ERROR_IF(srcSize < 5, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 2; here we need up to 5 for case 3"); |
| 138 | { size_t lhSize, litSize, litCSize; |
| 139 | U32 singleStream=0; |
| 140 | U32 const lhlCode = (istart[0] >> 2) & 3; |
| 141 | U32 const lhc = MEM_readLE32(istart); |
| 142 | size_t hufSuccess; |
| 143 | size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); |
| 144 | int const flags = 0 |
| 145 | | (ZSTD_DCtx_get_bmi2(dctx) ? HUF_flags_bmi2 : 0) |
| 146 | | (dctx->disableHufAsm ? HUF_flags_disableAsm : 0); |
| 147 | switch(lhlCode) |
| 148 | { |
| 149 | case 0: case 1: default: /* note : default is impossible, since lhlCode into [0..3] */ |
| 150 | /* 2 - 2 - 10 - 10 */ |
| 151 | singleStream = !lhlCode; |
| 152 | lhSize = 3; |
| 153 | litSize = (lhc >> 4) & 0x3FF; |
| 154 | litCSize = (lhc >> 14) & 0x3FF; |
| 155 | break; |
| 156 | case 2: |
| 157 | /* 2 - 2 - 14 - 14 */ |
| 158 | lhSize = 4; |
| 159 | litSize = (lhc >> 4) & 0x3FFF; |
| 160 | litCSize = lhc >> 18; |
| 161 | break; |
| 162 | case 3: |
| 163 | /* 2 - 2 - 18 - 18 */ |
| 164 | lhSize = 5; |
| 165 | litSize = (lhc >> 4) & 0x3FFFF; |
| 166 | litCSize = (lhc >> 22) + ((size_t)istart[4] << 10); |
| 167 | break; |
| 168 | } |
| 169 | RETURN_ERROR_IF(litSize > 0 && dst == NULL, dstSize_tooSmall, "NULL not handled"); |
| 170 | RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected, ""); |
| 171 | if (!singleStream) |
| 172 | RETURN_ERROR_IF(litSize < MIN_LITERALS_FOR_4_STREAMS, literals_headerWrong, |
| 173 | "Not enough literals (%zu) for the 4-streams mode (min %u)", |
| 174 | litSize, MIN_LITERALS_FOR_4_STREAMS); |
| 175 | RETURN_ERROR_IF(litCSize + lhSize > srcSize, corruption_detected, ""); |
| 176 | RETURN_ERROR_IF(expectedWriteSize < litSize , dstSize_tooSmall, ""); |
| 177 | ZSTD_allocateLiteralsBuffer(dctx, dst, dstCapacity, litSize, streaming, expectedWriteSize, 0); |
| 178 | |
| 179 | /* prefetch huffman table if cold */ |
| 180 | if (dctx->ddictIsCold && (litSize > 768 /* heuristic */)) { |
| 181 | PREFETCH_AREA(dctx->HUFptr, sizeof(dctx->entropy.hufTable)); |
| 182 | } |
| 183 | |
| 184 | if (litEncType==set_repeat) { |
| 185 | if (singleStream) { |
| 186 | hufSuccess = HUF_decompress1X_usingDTable( |
| 187 | dctx->litBuffer, litSize, istart+lhSize, litCSize, |
| 188 | dctx->HUFptr, flags); |
| 189 | } else { |
| 190 | assert(litSize >= MIN_LITERALS_FOR_4_STREAMS); |
| 191 | hufSuccess = HUF_decompress4X_usingDTable( |
| 192 | dctx->litBuffer, litSize, istart+lhSize, litCSize, |
| 193 | dctx->HUFptr, flags); |
| 194 | } |
| 195 | } else { |
| 196 | if (singleStream) { |
| 197 | #if defined(HUF_FORCE_DECOMPRESS_X2) |
| 198 | hufSuccess = HUF_decompress1X_DCtx_wksp( |
| 199 | dctx->entropy.hufTable, dctx->litBuffer, litSize, |
| 200 | istart+lhSize, litCSize, dctx->workspace, |
| 201 | sizeof(dctx->workspace), flags); |
| 202 | #else |
| 203 | hufSuccess = HUF_decompress1X1_DCtx_wksp( |
| 204 | dctx->entropy.hufTable, dctx->litBuffer, litSize, |
| 205 | istart+lhSize, litCSize, dctx->workspace, |
| 206 | sizeof(dctx->workspace), flags); |
| 207 | #endif |
| 208 | } else { |
| 209 | hufSuccess = HUF_decompress4X_hufOnly_wksp( |
| 210 | dctx->entropy.hufTable, dctx->litBuffer, litSize, |
| 211 | istart+lhSize, litCSize, dctx->workspace, |
| 212 | sizeof(dctx->workspace), flags); |
| 213 | } |
| 214 | } |
| 215 | if (dctx->litBufferLocation == ZSTD_split) |
| 216 | { |
| 217 | ZSTD_memcpy(dctx->litExtraBuffer, dctx->litBufferEnd - ZSTD_LITBUFFEREXTRASIZE, ZSTD_LITBUFFEREXTRASIZE); |
| 218 | ZSTD_memmove(dctx->litBuffer + ZSTD_LITBUFFEREXTRASIZE - WILDCOPY_OVERLENGTH, dctx->litBuffer, litSize - ZSTD_LITBUFFEREXTRASIZE); |
| 219 | dctx->litBuffer += ZSTD_LITBUFFEREXTRASIZE - WILDCOPY_OVERLENGTH; |
| 220 | dctx->litBufferEnd -= WILDCOPY_OVERLENGTH; |
| 221 | } |
| 222 | |
| 223 | RETURN_ERROR_IF(HUF_isError(hufSuccess), corruption_detected, ""); |
| 224 | |
| 225 | dctx->litPtr = dctx->litBuffer; |
| 226 | dctx->litSize = litSize; |
| 227 | dctx->litEntropy = 1; |
| 228 | if (litEncType==set_compressed) dctx->HUFptr = dctx->entropy.hufTable; |
| 229 | return litCSize + lhSize; |
| 230 | } |
| 231 | |
| 232 | case set_basic: |
| 233 | { size_t litSize, lhSize; |
| 234 | U32 const lhlCode = ((istart[0]) >> 2) & 3; |
| 235 | size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); |
| 236 | switch(lhlCode) |
| 237 | { |
| 238 | case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */ |
| 239 | lhSize = 1; |
| 240 | litSize = istart[0] >> 3; |
| 241 | break; |
| 242 | case 1: |
| 243 | lhSize = 2; |
| 244 | litSize = MEM_readLE16(istart) >> 4; |
| 245 | break; |
| 246 | case 3: |
| 247 | lhSize = 3; |
| 248 | RETURN_ERROR_IF(srcSize<3, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 2; here we need lhSize = 3"); |
| 249 | litSize = MEM_readLE24(istart) >> 4; |
| 250 | break; |
| 251 | } |
| 252 | |
| 253 | RETURN_ERROR_IF(litSize > 0 && dst == NULL, dstSize_tooSmall, "NULL not handled"); |
| 254 | RETURN_ERROR_IF(expectedWriteSize < litSize, dstSize_tooSmall, ""); |
| 255 | ZSTD_allocateLiteralsBuffer(dctx, dst, dstCapacity, litSize, streaming, expectedWriteSize, 1); |
| 256 | if (lhSize+litSize+WILDCOPY_OVERLENGTH > srcSize) { /* risk reading beyond src buffer with wildcopy */ |
| 257 | RETURN_ERROR_IF(litSize+lhSize > srcSize, corruption_detected, ""); |
| 258 | if (dctx->litBufferLocation == ZSTD_split) |
| 259 | { |
| 260 | ZSTD_memcpy(dctx->litBuffer, istart + lhSize, litSize - ZSTD_LITBUFFEREXTRASIZE); |
| 261 | ZSTD_memcpy(dctx->litExtraBuffer, istart + lhSize + litSize - ZSTD_LITBUFFEREXTRASIZE, ZSTD_LITBUFFEREXTRASIZE); |
| 262 | } |
| 263 | else |
| 264 | { |
| 265 | ZSTD_memcpy(dctx->litBuffer, istart + lhSize, litSize); |
| 266 | } |
| 267 | dctx->litPtr = dctx->litBuffer; |
| 268 | dctx->litSize = litSize; |
| 269 | return lhSize+litSize; |
| 270 | } |
| 271 | /* direct reference into compressed stream */ |
| 272 | dctx->litPtr = istart+lhSize; |
| 273 | dctx->litSize = litSize; |
| 274 | dctx->litBufferEnd = dctx->litPtr + litSize; |
| 275 | dctx->litBufferLocation = ZSTD_not_in_dst; |
| 276 | return lhSize+litSize; |
| 277 | } |
| 278 | |
| 279 | case set_rle: |
| 280 | { U32 const lhlCode = ((istart[0]) >> 2) & 3; |
| 281 | size_t litSize, lhSize; |
| 282 | size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); |
| 283 | switch(lhlCode) |
| 284 | { |
| 285 | case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */ |
| 286 | lhSize = 1; |
| 287 | litSize = istart[0] >> 3; |
| 288 | break; |
| 289 | case 1: |
| 290 | lhSize = 2; |
| 291 | RETURN_ERROR_IF(srcSize<3, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 2; here we need lhSize+1 = 3"); |
| 292 | litSize = MEM_readLE16(istart) >> 4; |
| 293 | break; |
| 294 | case 3: |
| 295 | lhSize = 3; |
| 296 | RETURN_ERROR_IF(srcSize<4, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 2; here we need lhSize+1 = 4"); |
| 297 | litSize = MEM_readLE24(istart) >> 4; |
| 298 | break; |
| 299 | } |
| 300 | RETURN_ERROR_IF(litSize > 0 && dst == NULL, dstSize_tooSmall, "NULL not handled"); |
| 301 | RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected, ""); |
| 302 | RETURN_ERROR_IF(expectedWriteSize < litSize, dstSize_tooSmall, ""); |
| 303 | ZSTD_allocateLiteralsBuffer(dctx, dst, dstCapacity, litSize, streaming, expectedWriteSize, 1); |
| 304 | if (dctx->litBufferLocation == ZSTD_split) |
| 305 | { |
| 306 | ZSTD_memset(dctx->litBuffer, istart[lhSize], litSize - ZSTD_LITBUFFEREXTRASIZE); |
| 307 | ZSTD_memset(dctx->litExtraBuffer, istart[lhSize], ZSTD_LITBUFFEREXTRASIZE); |
| 308 | } |
| 309 | else |
| 310 | { |
| 311 | ZSTD_memset(dctx->litBuffer, istart[lhSize], litSize); |
| 312 | } |
| 313 | dctx->litPtr = dctx->litBuffer; |
| 314 | dctx->litSize = litSize; |
| 315 | return lhSize+1; |
| 316 | } |
| 317 | default: |
| 318 | RETURN_ERROR(corruption_detected, "impossible"); |
| 319 | } |
| 320 | } |
| 321 | } |
| 322 | |
| 323 | /* Default FSE distribution tables. |
| 324 | * These are pre-calculated FSE decoding tables using default distributions as defined in specification : |
| 325 | * https://github.com/facebook/zstd/blob/release/doc/zstd_compression_format.md#default-distributions |
| 326 | * They were generated programmatically with following method : |
| 327 | * - start from default distributions, present in /lib/common/zstd_internal.h |
| 328 | * - generate tables normally, using ZSTD_buildFSETable() |
| 329 | * - printout the content of tables |
| 330 | * - pretify output, report below, test with fuzzer to ensure it's correct */ |
| 331 | |
| 332 | /* Default FSE distribution table for Literal Lengths */ |
| 333 | static const ZSTD_seqSymbol LL_defaultDTable[(1<<LL_DEFAULTNORMLOG)+1] = { |
| 334 | { 1, 1, 1, LL_DEFAULTNORMLOG}, /* header : fastMode, tableLog */ |
| 335 | /* nextState, nbAddBits, nbBits, baseVal */ |
| 336 | { 0, 0, 4, 0}, { 16, 0, 4, 0}, |
| 337 | { 32, 0, 5, 1}, { 0, 0, 5, 3}, |
| 338 | { 0, 0, 5, 4}, { 0, 0, 5, 6}, |
| 339 | { 0, 0, 5, 7}, { 0, 0, 5, 9}, |
| 340 | { 0, 0, 5, 10}, { 0, 0, 5, 12}, |
| 341 | { 0, 0, 6, 14}, { 0, 1, 5, 16}, |
| 342 | { 0, 1, 5, 20}, { 0, 1, 5, 22}, |
| 343 | { 0, 2, 5, 28}, { 0, 3, 5, 32}, |
| 344 | { 0, 4, 5, 48}, { 32, 6, 5, 64}, |
| 345 | { 0, 7, 5, 128}, { 0, 8, 6, 256}, |
| 346 | { 0, 10, 6, 1024}, { 0, 12, 6, 4096}, |
| 347 | { 32, 0, 4, 0}, { 0, 0, 4, 1}, |
| 348 | { 0, 0, 5, 2}, { 32, 0, 5, 4}, |
| 349 | { 0, 0, 5, 5}, { 32, 0, 5, 7}, |
| 350 | { 0, 0, 5, 8}, { 32, 0, 5, 10}, |
| 351 | { 0, 0, 5, 11}, { 0, 0, 6, 13}, |
| 352 | { 32, 1, 5, 16}, { 0, 1, 5, 18}, |
| 353 | { 32, 1, 5, 22}, { 0, 2, 5, 24}, |
| 354 | { 32, 3, 5, 32}, { 0, 3, 5, 40}, |
| 355 | { 0, 6, 4, 64}, { 16, 6, 4, 64}, |
| 356 | { 32, 7, 5, 128}, { 0, 9, 6, 512}, |
| 357 | { 0, 11, 6, 2048}, { 48, 0, 4, 0}, |
| 358 | { 16, 0, 4, 1}, { 32, 0, 5, 2}, |
| 359 | { 32, 0, 5, 3}, { 32, 0, 5, 5}, |
| 360 | { 32, 0, 5, 6}, { 32, 0, 5, 8}, |
| 361 | { 32, 0, 5, 9}, { 32, 0, 5, 11}, |
| 362 | { 32, 0, 5, 12}, { 0, 0, 6, 15}, |
| 363 | { 32, 1, 5, 18}, { 32, 1, 5, 20}, |
| 364 | { 32, 2, 5, 24}, { 32, 2, 5, 28}, |
| 365 | { 32, 3, 5, 40}, { 32, 4, 5, 48}, |
| 366 | { 0, 16, 6,65536}, { 0, 15, 6,32768}, |
| 367 | { 0, 14, 6,16384}, { 0, 13, 6, 8192}, |
| 368 | }; /* LL_defaultDTable */ |
| 369 | |
| 370 | /* Default FSE distribution table for Offset Codes */ |
| 371 | static const ZSTD_seqSymbol OF_defaultDTable[(1<<OF_DEFAULTNORMLOG)+1] = { |
| 372 | { 1, 1, 1, OF_DEFAULTNORMLOG}, /* header : fastMode, tableLog */ |
| 373 | /* nextState, nbAddBits, nbBits, baseVal */ |
| 374 | { 0, 0, 5, 0}, { 0, 6, 4, 61}, |
| 375 | { 0, 9, 5, 509}, { 0, 15, 5,32765}, |
| 376 | { 0, 21, 5,2097149}, { 0, 3, 5, 5}, |
| 377 | { 0, 7, 4, 125}, { 0, 12, 5, 4093}, |
| 378 | { 0, 18, 5,262141}, { 0, 23, 5,8388605}, |
| 379 | { 0, 5, 5, 29}, { 0, 8, 4, 253}, |
| 380 | { 0, 14, 5,16381}, { 0, 20, 5,1048573}, |
| 381 | { 0, 2, 5, 1}, { 16, 7, 4, 125}, |
| 382 | { 0, 11, 5, 2045}, { 0, 17, 5,131069}, |
| 383 | { 0, 22, 5,4194301}, { 0, 4, 5, 13}, |
| 384 | { 16, 8, 4, 253}, { 0, 13, 5, 8189}, |
| 385 | { 0, 19, 5,524285}, { 0, 1, 5, 1}, |
| 386 | { 16, 6, 4, 61}, { 0, 10, 5, 1021}, |
| 387 | { 0, 16, 5,65533}, { 0, 28, 5,268435453}, |
| 388 | { 0, 27, 5,134217725}, { 0, 26, 5,67108861}, |
| 389 | { 0, 25, 5,33554429}, { 0, 24, 5,16777213}, |
| 390 | }; /* OF_defaultDTable */ |
| 391 | |
| 392 | |
| 393 | /* Default FSE distribution table for Match Lengths */ |
| 394 | static const ZSTD_seqSymbol ML_defaultDTable[(1<<ML_DEFAULTNORMLOG)+1] = { |
| 395 | { 1, 1, 1, ML_DEFAULTNORMLOG}, /* header : fastMode, tableLog */ |
| 396 | /* nextState, nbAddBits, nbBits, baseVal */ |
| 397 | { 0, 0, 6, 3}, { 0, 0, 4, 4}, |
| 398 | { 32, 0, 5, 5}, { 0, 0, 5, 6}, |
| 399 | { 0, 0, 5, 8}, { 0, 0, 5, 9}, |
| 400 | { 0, 0, 5, 11}, { 0, 0, 6, 13}, |
| 401 | { 0, 0, 6, 16}, { 0, 0, 6, 19}, |
| 402 | { 0, 0, 6, 22}, { 0, 0, 6, 25}, |
| 403 | { 0, 0, 6, 28}, { 0, 0, 6, 31}, |
| 404 | { 0, 0, 6, 34}, { 0, 1, 6, 37}, |
| 405 | { 0, 1, 6, 41}, { 0, 2, 6, 47}, |
| 406 | { 0, 3, 6, 59}, { 0, 4, 6, 83}, |
| 407 | { 0, 7, 6, 131}, { 0, 9, 6, 515}, |
| 408 | { 16, 0, 4, 4}, { 0, 0, 4, 5}, |
| 409 | { 32, 0, 5, 6}, { 0, 0, 5, 7}, |
| 410 | { 32, 0, 5, 9}, { 0, 0, 5, 10}, |
| 411 | { 0, 0, 6, 12}, { 0, 0, 6, 15}, |
| 412 | { 0, 0, 6, 18}, { 0, 0, 6, 21}, |
| 413 | { 0, 0, 6, 24}, { 0, 0, 6, 27}, |
| 414 | { 0, 0, 6, 30}, { 0, 0, 6, 33}, |
| 415 | { 0, 1, 6, 35}, { 0, 1, 6, 39}, |
| 416 | { 0, 2, 6, 43}, { 0, 3, 6, 51}, |
| 417 | { 0, 4, 6, 67}, { 0, 5, 6, 99}, |
| 418 | { 0, 8, 6, 259}, { 32, 0, 4, 4}, |
| 419 | { 48, 0, 4, 4}, { 16, 0, 4, 5}, |
| 420 | { 32, 0, 5, 7}, { 32, 0, 5, 8}, |
| 421 | { 32, 0, 5, 10}, { 32, 0, 5, 11}, |
| 422 | { 0, 0, 6, 14}, { 0, 0, 6, 17}, |
| 423 | { 0, 0, 6, 20}, { 0, 0, 6, 23}, |
| 424 | { 0, 0, 6, 26}, { 0, 0, 6, 29}, |
| 425 | { 0, 0, 6, 32}, { 0, 16, 6,65539}, |
| 426 | { 0, 15, 6,32771}, { 0, 14, 6,16387}, |
| 427 | { 0, 13, 6, 8195}, { 0, 12, 6, 4099}, |
| 428 | { 0, 11, 6, 2051}, { 0, 10, 6, 1027}, |
| 429 | }; /* ML_defaultDTable */ |
| 430 | |
| 431 | |
| 432 | static void ZSTD_buildSeqTable_rle(ZSTD_seqSymbol* dt, U32 baseValue, U8 nbAddBits) |
| 433 | { |
| 434 | void* ptr = dt; |
| 435 | ZSTD_seqSymbol_header* const DTableH = (ZSTD_seqSymbol_header*)ptr; |
| 436 | ZSTD_seqSymbol* const cell = dt + 1; |
| 437 | |
| 438 | DTableH->tableLog = 0; |
| 439 | DTableH->fastMode = 0; |
| 440 | |
| 441 | cell->nbBits = 0; |
| 442 | cell->nextState = 0; |
| 443 | assert(nbAddBits < 255); |
| 444 | cell->nbAdditionalBits = nbAddBits; |
| 445 | cell->baseValue = baseValue; |
| 446 | } |
| 447 | |
| 448 | |
| 449 | /* ZSTD_buildFSETable() : |
| 450 | * generate FSE decoding table for one symbol (ll, ml or off) |
| 451 | * cannot fail if input is valid => |
| 452 | * all inputs are presumed validated at this stage */ |
| 453 | FORCE_INLINE_TEMPLATE |
| 454 | void ZSTD_buildFSETable_body(ZSTD_seqSymbol* dt, |
| 455 | const short* normalizedCounter, unsigned maxSymbolValue, |
| 456 | const U32* baseValue, const U8* nbAdditionalBits, |
| 457 | unsigned tableLog, void* wksp, size_t wkspSize) |
| 458 | { |
| 459 | ZSTD_seqSymbol* const tableDecode = dt+1; |
| 460 | U32 const maxSV1 = maxSymbolValue + 1; |
| 461 | U32 const tableSize = 1 << tableLog; |
| 462 | |
| 463 | U16* symbolNext = (U16*)wksp; |
| 464 | BYTE* spread = (BYTE*)(symbolNext + MaxSeq + 1); |
| 465 | U32 highThreshold = tableSize - 1; |
| 466 | |
| 467 | |
| 468 | /* Sanity Checks */ |
| 469 | assert(maxSymbolValue <= MaxSeq); |
| 470 | assert(tableLog <= MaxFSELog); |
| 471 | assert(wkspSize >= ZSTD_BUILD_FSE_TABLE_WKSP_SIZE); |
| 472 | (void)wkspSize; |
| 473 | /* Init, lay down lowprob symbols */ |
| 474 | { ZSTD_seqSymbol_header DTableH; |
| 475 | DTableH.tableLog = tableLog; |
| 476 | DTableH.fastMode = 1; |
| 477 | { S16 const largeLimit= (S16)(1 << (tableLog-1)); |
| 478 | U32 s; |
| 479 | for (s=0; s<maxSV1; s++) { |
| 480 | if (normalizedCounter[s]==-1) { |
| 481 | tableDecode[highThreshold--].baseValue = s; |
| 482 | symbolNext[s] = 1; |
| 483 | } else { |
| 484 | if (normalizedCounter[s] >= largeLimit) DTableH.fastMode=0; |
| 485 | assert(normalizedCounter[s]>=0); |
| 486 | symbolNext[s] = (U16)normalizedCounter[s]; |
| 487 | } } } |
| 488 | ZSTD_memcpy(dt, &DTableH, sizeof(DTableH)); |
| 489 | } |
| 490 | |
| 491 | /* Spread symbols */ |
| 492 | assert(tableSize <= 512); |
| 493 | /* Specialized symbol spreading for the case when there are |
| 494 | * no low probability (-1 count) symbols. When compressing |
| 495 | * small blocks we avoid low probability symbols to hit this |
| 496 | * case, since header decoding speed matters more. |
| 497 | */ |
| 498 | if (highThreshold == tableSize - 1) { |
| 499 | size_t const tableMask = tableSize-1; |
| 500 | size_t const step = FSE_TABLESTEP(tableSize); |
| 501 | /* First lay down the symbols in order. |
| 502 | * We use a uint64_t to lay down 8 bytes at a time. This reduces branch |
| 503 | * misses since small blocks generally have small table logs, so nearly |
| 504 | * all symbols have counts <= 8. We ensure we have 8 bytes at the end of |
| 505 | * our buffer to handle the over-write. |
| 506 | */ |
| 507 | { |
| 508 | U64 const add = 0x0101010101010101ull; |
| 509 | size_t pos = 0; |
| 510 | U64 sv = 0; |
| 511 | U32 s; |
| 512 | for (s=0; s<maxSV1; ++s, sv += add) { |
| 513 | int i; |
| 514 | int const n = normalizedCounter[s]; |
| 515 | MEM_write64(spread + pos, sv); |
| 516 | for (i = 8; i < n; i += 8) { |
| 517 | MEM_write64(spread + pos + i, sv); |
| 518 | } |
| 519 | assert(n>=0); |
| 520 | pos += (size_t)n; |
| 521 | } |
| 522 | } |
| 523 | /* Now we spread those positions across the table. |
| 524 | * The benefit of doing it in two stages is that we avoid the |
| 525 | * variable size inner loop, which caused lots of branch misses. |
| 526 | * Now we can run through all the positions without any branch misses. |
| 527 | * We unroll the loop twice, since that is what empirically worked best. |
| 528 | */ |
| 529 | { |
| 530 | size_t position = 0; |
| 531 | size_t s; |
| 532 | size_t const unroll = 2; |
| 533 | assert(tableSize % unroll == 0); /* FSE_MIN_TABLELOG is 5 */ |
| 534 | for (s = 0; s < (size_t)tableSize; s += unroll) { |
| 535 | size_t u; |
| 536 | for (u = 0; u < unroll; ++u) { |
| 537 | size_t const uPosition = (position + (u * step)) & tableMask; |
| 538 | tableDecode[uPosition].baseValue = spread[s + u]; |
| 539 | } |
| 540 | position = (position + (unroll * step)) & tableMask; |
| 541 | } |
| 542 | assert(position == 0); |
| 543 | } |
| 544 | } else { |
| 545 | U32 const tableMask = tableSize-1; |
| 546 | U32 const step = FSE_TABLESTEP(tableSize); |
| 547 | U32 s, position = 0; |
| 548 | for (s=0; s<maxSV1; s++) { |
| 549 | int i; |
| 550 | int const n = normalizedCounter[s]; |
| 551 | for (i=0; i<n; i++) { |
| 552 | tableDecode[position].baseValue = s; |
| 553 | position = (position + step) & tableMask; |
| 554 | while (UNLIKELY(position > highThreshold)) position = (position + step) & tableMask; /* lowprob area */ |
| 555 | } } |
| 556 | assert(position == 0); /* position must reach all cells once, otherwise normalizedCounter is incorrect */ |
| 557 | } |
| 558 | |
| 559 | /* Build Decoding table */ |
| 560 | { |
| 561 | U32 u; |
| 562 | for (u=0; u<tableSize; u++) { |
| 563 | U32 const symbol = tableDecode[u].baseValue; |
| 564 | U32 const nextState = symbolNext[symbol]++; |
| 565 | tableDecode[u].nbBits = (BYTE) (tableLog - ZSTD_highbit32(nextState) ); |
| 566 | tableDecode[u].nextState = (U16) ( (nextState << tableDecode[u].nbBits) - tableSize); |
| 567 | assert(nbAdditionalBits[symbol] < 255); |
| 568 | tableDecode[u].nbAdditionalBits = nbAdditionalBits[symbol]; |
| 569 | tableDecode[u].baseValue = baseValue[symbol]; |
| 570 | } |
| 571 | } |
| 572 | } |
| 573 | |
| 574 | /* Avoids the FORCE_INLINE of the _body() function. */ |
| 575 | static void ZSTD_buildFSETable_body_default(ZSTD_seqSymbol* dt, |
| 576 | const short* normalizedCounter, unsigned maxSymbolValue, |
| 577 | const U32* baseValue, const U8* nbAdditionalBits, |
| 578 | unsigned tableLog, void* wksp, size_t wkspSize) |
| 579 | { |
| 580 | ZSTD_buildFSETable_body(dt, normalizedCounter, maxSymbolValue, |
| 581 | baseValue, nbAdditionalBits, tableLog, wksp, wkspSize); |
| 582 | } |
| 583 | |
| 584 | #if DYNAMIC_BMI2 |
| 585 | BMI2_TARGET_ATTRIBUTE static void ZSTD_buildFSETable_body_bmi2(ZSTD_seqSymbol* dt, |
| 586 | const short* normalizedCounter, unsigned maxSymbolValue, |
| 587 | const U32* baseValue, const U8* nbAdditionalBits, |
| 588 | unsigned tableLog, void* wksp, size_t wkspSize) |
| 589 | { |
| 590 | ZSTD_buildFSETable_body(dt, normalizedCounter, maxSymbolValue, |
| 591 | baseValue, nbAdditionalBits, tableLog, wksp, wkspSize); |
| 592 | } |
| 593 | #endif |
| 594 | |
| 595 | void ZSTD_buildFSETable(ZSTD_seqSymbol* dt, |
| 596 | const short* normalizedCounter, unsigned maxSymbolValue, |
| 597 | const U32* baseValue, const U8* nbAdditionalBits, |
| 598 | unsigned tableLog, void* wksp, size_t wkspSize, int bmi2) |
| 599 | { |
| 600 | #if DYNAMIC_BMI2 |
| 601 | if (bmi2) { |
| 602 | ZSTD_buildFSETable_body_bmi2(dt, normalizedCounter, maxSymbolValue, |
| 603 | baseValue, nbAdditionalBits, tableLog, wksp, wkspSize); |
| 604 | return; |
| 605 | } |
| 606 | #endif |
| 607 | (void)bmi2; |
| 608 | ZSTD_buildFSETable_body_default(dt, normalizedCounter, maxSymbolValue, |
| 609 | baseValue, nbAdditionalBits, tableLog, wksp, wkspSize); |
| 610 | } |
| 611 | |
| 612 | |
| 613 | /*! ZSTD_buildSeqTable() : |
| 614 | * @return : nb bytes read from src, |
| 615 | * or an error code if it fails */ |
| 616 | static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymbol** DTablePtr, |
| 617 | symbolEncodingType_e type, unsigned max, U32 maxLog, |
| 618 | const void* src, size_t srcSize, |
| 619 | const U32* baseValue, const U8* nbAdditionalBits, |
| 620 | const ZSTD_seqSymbol* defaultTable, U32 flagRepeatTable, |
| 621 | int ddictIsCold, int nbSeq, U32* wksp, size_t wkspSize, |
| 622 | int bmi2) |
| 623 | { |
| 624 | switch(type) |
| 625 | { |
| 626 | case set_rle : |
| 627 | RETURN_ERROR_IF(!srcSize, srcSize_wrong, ""); |
| 628 | RETURN_ERROR_IF((*(const BYTE*)src) > max, corruption_detected, ""); |
| 629 | { U32 const symbol = *(const BYTE*)src; |
| 630 | U32 const baseline = baseValue[symbol]; |
| 631 | U8 const nbBits = nbAdditionalBits[symbol]; |
| 632 | ZSTD_buildSeqTable_rle(DTableSpace, baseline, nbBits); |
| 633 | } |
| 634 | *DTablePtr = DTableSpace; |
| 635 | return 1; |
| 636 | case set_basic : |
| 637 | *DTablePtr = defaultTable; |
| 638 | return 0; |
| 639 | case set_repeat: |
| 640 | RETURN_ERROR_IF(!flagRepeatTable, corruption_detected, ""); |
| 641 | /* prefetch FSE table if used */ |
| 642 | if (ddictIsCold && (nbSeq > 24 /* heuristic */)) { |
| 643 | const void* const pStart = *DTablePtr; |
| 644 | size_t const pSize = sizeof(ZSTD_seqSymbol) * (SEQSYMBOL_TABLE_SIZE(maxLog)); |
| 645 | PREFETCH_AREA(pStart, pSize); |
| 646 | } |
| 647 | return 0; |
| 648 | case set_compressed : |
| 649 | { unsigned tableLog; |
| 650 | S16 norm[MaxSeq+1]; |
| 651 | size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize); |
| 652 | RETURN_ERROR_IF(FSE_isError(headerSize), corruption_detected, ""); |
| 653 | RETURN_ERROR_IF(tableLog > maxLog, corruption_detected, ""); |
| 654 | ZSTD_buildFSETable(DTableSpace, norm, max, baseValue, nbAdditionalBits, tableLog, wksp, wkspSize, bmi2); |
| 655 | *DTablePtr = DTableSpace; |
| 656 | return headerSize; |
| 657 | } |
| 658 | default : |
| 659 | assert(0); |
| 660 | RETURN_ERROR(GENERIC, "impossible"); |
| 661 | } |
| 662 | } |
| 663 | |
| 664 | size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr, |
| 665 | const void* src, size_t srcSize) |
| 666 | { |
| 667 | const BYTE* const istart = (const BYTE*)src; |
| 668 | const BYTE* const iend = istart + srcSize; |
| 669 | const BYTE* ip = istart; |
| 670 | int nbSeq; |
| 671 | DEBUGLOG(5, "ZSTD_decodeSeqHeaders"); |
| 672 | |
| 673 | /* check */ |
| 674 | RETURN_ERROR_IF(srcSize < MIN_SEQUENCES_SIZE, srcSize_wrong, ""); |
| 675 | |
| 676 | /* SeqHead */ |
| 677 | nbSeq = *ip++; |
| 678 | if (!nbSeq) { |
| 679 | *nbSeqPtr=0; |
| 680 | RETURN_ERROR_IF(srcSize != 1, srcSize_wrong, ""); |
| 681 | return 1; |
| 682 | } |
| 683 | if (nbSeq > 0x7F) { |
| 684 | if (nbSeq == 0xFF) { |
| 685 | RETURN_ERROR_IF(ip+2 > iend, srcSize_wrong, ""); |
| 686 | nbSeq = MEM_readLE16(ip) + LONGNBSEQ; |
| 687 | ip+=2; |
| 688 | } else { |
| 689 | RETURN_ERROR_IF(ip >= iend, srcSize_wrong, ""); |
| 690 | nbSeq = ((nbSeq-0x80)<<8) + *ip++; |
| 691 | } |
| 692 | } |
| 693 | *nbSeqPtr = nbSeq; |
| 694 | |
| 695 | /* FSE table descriptors */ |
| 696 | RETURN_ERROR_IF(ip+1 > iend, srcSize_wrong, ""); /* minimum possible size: 1 byte for symbol encoding types */ |
| 697 | { symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip >> 6); |
| 698 | symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip >> 4) & 3); |
| 699 | symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip >> 2) & 3); |
| 700 | ip++; |
| 701 | |
| 702 | /* Build DTables */ |
| 703 | { size_t const llhSize = ZSTD_buildSeqTable(dctx->entropy.LLTable, &dctx->LLTptr, |
| 704 | LLtype, MaxLL, LLFSELog, |
| 705 | ip, iend-ip, |
| 706 | LL_base, LL_bits, |
| 707 | LL_defaultDTable, dctx->fseEntropy, |
| 708 | dctx->ddictIsCold, nbSeq, |
| 709 | dctx->workspace, sizeof(dctx->workspace), |
| 710 | ZSTD_DCtx_get_bmi2(dctx)); |
| 711 | RETURN_ERROR_IF(ZSTD_isError(llhSize), corruption_detected, "ZSTD_buildSeqTable failed"); |
| 712 | ip += llhSize; |
| 713 | } |
| 714 | |
| 715 | { size_t const ofhSize = ZSTD_buildSeqTable(dctx->entropy.OFTable, &dctx->OFTptr, |
| 716 | OFtype, MaxOff, OffFSELog, |
| 717 | ip, iend-ip, |
| 718 | OF_base, OF_bits, |
| 719 | OF_defaultDTable, dctx->fseEntropy, |
| 720 | dctx->ddictIsCold, nbSeq, |
| 721 | dctx->workspace, sizeof(dctx->workspace), |
| 722 | ZSTD_DCtx_get_bmi2(dctx)); |
| 723 | RETURN_ERROR_IF(ZSTD_isError(ofhSize), corruption_detected, "ZSTD_buildSeqTable failed"); |
| 724 | ip += ofhSize; |
| 725 | } |
| 726 | |
| 727 | { size_t const mlhSize = ZSTD_buildSeqTable(dctx->entropy.MLTable, &dctx->MLTptr, |
| 728 | MLtype, MaxML, MLFSELog, |
| 729 | ip, iend-ip, |
| 730 | ML_base, ML_bits, |
| 731 | ML_defaultDTable, dctx->fseEntropy, |
| 732 | dctx->ddictIsCold, nbSeq, |
| 733 | dctx->workspace, sizeof(dctx->workspace), |
| 734 | ZSTD_DCtx_get_bmi2(dctx)); |
| 735 | RETURN_ERROR_IF(ZSTD_isError(mlhSize), corruption_detected, "ZSTD_buildSeqTable failed"); |
| 736 | ip += mlhSize; |
| 737 | } |
| 738 | } |
| 739 | |
| 740 | return ip-istart; |
| 741 | } |
| 742 | |
| 743 | |
| 744 | typedef struct { |
| 745 | size_t litLength; |
| 746 | size_t matchLength; |
| 747 | size_t offset; |
| 748 | } seq_t; |
| 749 | |
| 750 | typedef struct { |
| 751 | size_t state; |
| 752 | const ZSTD_seqSymbol* table; |
| 753 | } ZSTD_fseState; |
| 754 | |
| 755 | typedef struct { |
| 756 | BIT_DStream_t DStream; |
| 757 | ZSTD_fseState stateLL; |
| 758 | ZSTD_fseState stateOffb; |
| 759 | ZSTD_fseState stateML; |
| 760 | size_t prevOffset[ZSTD_REP_NUM]; |
| 761 | } seqState_t; |
| 762 | |
| 763 | /*! ZSTD_overlapCopy8() : |
| 764 | * Copies 8 bytes from ip to op and updates op and ip where ip <= op. |
| 765 | * If the offset is < 8 then the offset is spread to at least 8 bytes. |
| 766 | * |
| 767 | * Precondition: *ip <= *op |
| 768 | * Postcondition: *op - *op >= 8 |
| 769 | */ |
| 770 | HINT_INLINE void ZSTD_overlapCopy8(BYTE** op, BYTE const** ip, size_t offset) { |
| 771 | assert(*ip <= *op); |
| 772 | if (offset < 8) { |
| 773 | /* close range match, overlap */ |
| 774 | static const U32 dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 }; /* added */ |
| 775 | static const int dec64table[] = { 8, 8, 8, 7, 8, 9,10,11 }; /* subtracted */ |
| 776 | int const sub2 = dec64table[offset]; |
| 777 | (*op)[0] = (*ip)[0]; |
| 778 | (*op)[1] = (*ip)[1]; |
| 779 | (*op)[2] = (*ip)[2]; |
| 780 | (*op)[3] = (*ip)[3]; |
| 781 | *ip += dec32table[offset]; |
| 782 | ZSTD_copy4(*op+4, *ip); |
| 783 | *ip -= sub2; |
| 784 | } else { |
| 785 | ZSTD_copy8(*op, *ip); |
| 786 | } |
| 787 | *ip += 8; |
| 788 | *op += 8; |
| 789 | assert(*op - *ip >= 8); |
| 790 | } |
| 791 | |
| 792 | /*! ZSTD_safecopy() : |
| 793 | * Specialized version of memcpy() that is allowed to READ up to WILDCOPY_OVERLENGTH past the input buffer |
| 794 | * and write up to 16 bytes past oend_w (op >= oend_w is allowed). |
| 795 | * This function is only called in the uncommon case where the sequence is near the end of the block. It |
| 796 | * should be fast for a single long sequence, but can be slow for several short sequences. |
| 797 | * |
| 798 | * @param ovtype controls the overlap detection |
| 799 | * - ZSTD_no_overlap: The source and destination are guaranteed to be at least WILDCOPY_VECLEN bytes apart. |
| 800 | * - ZSTD_overlap_src_before_dst: The src and dst may overlap and may be any distance apart. |
| 801 | * The src buffer must be before the dst buffer. |
| 802 | */ |
| 803 | static void ZSTD_safecopy(BYTE* op, const BYTE* const oend_w, BYTE const* ip, ptrdiff_t length, ZSTD_overlap_e ovtype) { |
| 804 | ptrdiff_t const diff = op - ip; |
| 805 | BYTE* const oend = op + length; |
| 806 | |
| 807 | assert((ovtype == ZSTD_no_overlap && (diff <= -8 || diff >= 8 || op >= oend_w)) || |
| 808 | (ovtype == ZSTD_overlap_src_before_dst && diff >= 0)); |
| 809 | |
| 810 | if (length < 8) { |
| 811 | /* Handle short lengths. */ |
| 812 | while (op < oend) *op++ = *ip++; |
| 813 | return; |
| 814 | } |
| 815 | if (ovtype == ZSTD_overlap_src_before_dst) { |
| 816 | /* Copy 8 bytes and ensure the offset >= 8 when there can be overlap. */ |
| 817 | assert(length >= 8); |
| 818 | ZSTD_overlapCopy8(&op, &ip, diff); |
| 819 | length -= 8; |
| 820 | assert(op - ip >= 8); |
| 821 | assert(op <= oend); |
| 822 | } |
| 823 | |
| 824 | if (oend <= oend_w) { |
| 825 | /* No risk of overwrite. */ |
| 826 | ZSTD_wildcopy(op, ip, length, ovtype); |
| 827 | return; |
| 828 | } |
| 829 | if (op <= oend_w) { |
| 830 | /* Wildcopy until we get close to the end. */ |
| 831 | assert(oend > oend_w); |
| 832 | ZSTD_wildcopy(op, ip, oend_w - op, ovtype); |
| 833 | ip += oend_w - op; |
| 834 | op += oend_w - op; |
| 835 | } |
| 836 | /* Handle the leftovers. */ |
| 837 | while (op < oend) *op++ = *ip++; |
| 838 | } |
| 839 | |
| 840 | /* ZSTD_safecopyDstBeforeSrc(): |
| 841 | * This version allows overlap with dst before src, or handles the non-overlap case with dst after src |
| 842 | * Kept separate from more common ZSTD_safecopy case to avoid performance impact to the safecopy common case */ |
| 843 | static void ZSTD_safecopyDstBeforeSrc(BYTE* op, BYTE const* ip, ptrdiff_t length) { |
| 844 | ptrdiff_t const diff = op - ip; |
| 845 | BYTE* const oend = op + length; |
| 846 | |
| 847 | if (length < 8 || diff > -8) { |
| 848 | /* Handle short lengths, close overlaps, and dst not before src. */ |
| 849 | while (op < oend) *op++ = *ip++; |
| 850 | return; |
| 851 | } |
| 852 | |
| 853 | if (op <= oend - WILDCOPY_OVERLENGTH && diff < -WILDCOPY_VECLEN) { |
| 854 | ZSTD_wildcopy(op, ip, oend - WILDCOPY_OVERLENGTH - op, ZSTD_no_overlap); |
| 855 | ip += oend - WILDCOPY_OVERLENGTH - op; |
| 856 | op += oend - WILDCOPY_OVERLENGTH - op; |
| 857 | } |
| 858 | |
| 859 | /* Handle the leftovers. */ |
| 860 | while (op < oend) *op++ = *ip++; |
| 861 | } |
| 862 | |
| 863 | /* ZSTD_execSequenceEnd(): |
| 864 | * This version handles cases that are near the end of the output buffer. It requires |
| 865 | * more careful checks to make sure there is no overflow. By separating out these hard |
| 866 | * and unlikely cases, we can speed up the common cases. |
| 867 | * |
| 868 | * NOTE: This function needs to be fast for a single long sequence, but doesn't need |
| 869 | * to be optimized for many small sequences, since those fall into ZSTD_execSequence(). |
| 870 | */ |
| 871 | FORCE_NOINLINE |
| 872 | size_t ZSTD_execSequenceEnd(BYTE* op, |
| 873 | BYTE* const oend, seq_t sequence, |
| 874 | const BYTE** litPtr, const BYTE* const litLimit, |
| 875 | const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) |
| 876 | { |
| 877 | BYTE* const oLitEnd = op + sequence.litLength; |
| 878 | size_t const sequenceLength = sequence.litLength + sequence.matchLength; |
| 879 | const BYTE* const iLitEnd = *litPtr + sequence.litLength; |
| 880 | const BYTE* match = oLitEnd - sequence.offset; |
| 881 | BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH; |
| 882 | |
| 883 | /* bounds checks : careful of address space overflow in 32-bit mode */ |
| 884 | RETURN_ERROR_IF(sequenceLength > (size_t)(oend - op), dstSize_tooSmall, "last match must fit within dstBuffer"); |
| 885 | RETURN_ERROR_IF(sequence.litLength > (size_t)(litLimit - *litPtr), corruption_detected, "try to read beyond literal buffer"); |
| 886 | assert(op < op + sequenceLength); |
| 887 | assert(oLitEnd < op + sequenceLength); |
| 888 | |
| 889 | /* copy literals */ |
| 890 | ZSTD_safecopy(op, oend_w, *litPtr, sequence.litLength, ZSTD_no_overlap); |
| 891 | op = oLitEnd; |
| 892 | *litPtr = iLitEnd; |
| 893 | |
| 894 | /* copy Match */ |
| 895 | if (sequence.offset > (size_t)(oLitEnd - prefixStart)) { |
| 896 | /* offset beyond prefix */ |
| 897 | RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - virtualStart), corruption_detected, ""); |
| 898 | match = dictEnd - (prefixStart - match); |
| 899 | if (match + sequence.matchLength <= dictEnd) { |
| 900 | ZSTD_memmove(oLitEnd, match, sequence.matchLength); |
| 901 | return sequenceLength; |
| 902 | } |
| 903 | /* span extDict & currentPrefixSegment */ |
| 904 | { size_t const length1 = dictEnd - match; |
| 905 | ZSTD_memmove(oLitEnd, match, length1); |
| 906 | op = oLitEnd + length1; |
| 907 | sequence.matchLength -= length1; |
| 908 | match = prefixStart; |
| 909 | } |
| 910 | } |
| 911 | ZSTD_safecopy(op, oend_w, match, sequence.matchLength, ZSTD_overlap_src_before_dst); |
| 912 | return sequenceLength; |
| 913 | } |
| 914 | |
| 915 | /* ZSTD_execSequenceEndSplitLitBuffer(): |
| 916 | * This version is intended to be used during instances where the litBuffer is still split. It is kept separate to avoid performance impact for the good case. |
| 917 | */ |
| 918 | FORCE_NOINLINE |
| 919 | size_t ZSTD_execSequenceEndSplitLitBuffer(BYTE* op, |
| 920 | BYTE* const oend, const BYTE* const oend_w, seq_t sequence, |
| 921 | const BYTE** litPtr, const BYTE* const litLimit, |
| 922 | const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) |
| 923 | { |
| 924 | BYTE* const oLitEnd = op + sequence.litLength; |
| 925 | size_t const sequenceLength = sequence.litLength + sequence.matchLength; |
| 926 | const BYTE* const iLitEnd = *litPtr + sequence.litLength; |
| 927 | const BYTE* match = oLitEnd - sequence.offset; |
| 928 | |
| 929 | |
| 930 | /* bounds checks : careful of address space overflow in 32-bit mode */ |
| 931 | RETURN_ERROR_IF(sequenceLength > (size_t)(oend - op), dstSize_tooSmall, "last match must fit within dstBuffer"); |
| 932 | RETURN_ERROR_IF(sequence.litLength > (size_t)(litLimit - *litPtr), corruption_detected, "try to read beyond literal buffer"); |
| 933 | assert(op < op + sequenceLength); |
| 934 | assert(oLitEnd < op + sequenceLength); |
| 935 | |
| 936 | /* copy literals */ |
| 937 | RETURN_ERROR_IF(op > *litPtr && op < *litPtr + sequence.litLength, dstSize_tooSmall, "output should not catch up to and overwrite literal buffer"); |
| 938 | ZSTD_safecopyDstBeforeSrc(op, *litPtr, sequence.litLength); |
| 939 | op = oLitEnd; |
| 940 | *litPtr = iLitEnd; |
| 941 | |
| 942 | /* copy Match */ |
| 943 | if (sequence.offset > (size_t)(oLitEnd - prefixStart)) { |
| 944 | /* offset beyond prefix */ |
| 945 | RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - virtualStart), corruption_detected, ""); |
| 946 | match = dictEnd - (prefixStart - match); |
| 947 | if (match + sequence.matchLength <= dictEnd) { |
| 948 | ZSTD_memmove(oLitEnd, match, sequence.matchLength); |
| 949 | return sequenceLength; |
| 950 | } |
| 951 | /* span extDict & currentPrefixSegment */ |
| 952 | { size_t const length1 = dictEnd - match; |
| 953 | ZSTD_memmove(oLitEnd, match, length1); |
| 954 | op = oLitEnd + length1; |
| 955 | sequence.matchLength -= length1; |
| 956 | match = prefixStart; |
| 957 | } |
| 958 | } |
| 959 | ZSTD_safecopy(op, oend_w, match, sequence.matchLength, ZSTD_overlap_src_before_dst); |
| 960 | return sequenceLength; |
| 961 | } |
| 962 | |
| 963 | HINT_INLINE |
| 964 | size_t ZSTD_execSequence(BYTE* op, |
| 965 | BYTE* const oend, seq_t sequence, |
| 966 | const BYTE** litPtr, const BYTE* const litLimit, |
| 967 | const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) |
| 968 | { |
| 969 | BYTE* const oLitEnd = op + sequence.litLength; |
| 970 | size_t const sequenceLength = sequence.litLength + sequence.matchLength; |
| 971 | BYTE* const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */ |
| 972 | BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH; /* risk : address space underflow on oend=NULL */ |
| 973 | const BYTE* const iLitEnd = *litPtr + sequence.litLength; |
| 974 | const BYTE* match = oLitEnd - sequence.offset; |
| 975 | |
| 976 | assert(op != NULL /* Precondition */); |
| 977 | assert(oend_w < oend /* No underflow */); |
| 978 | |
| 979 | #if defined(__aarch64__) |
| 980 | /* prefetch sequence starting from match that will be used for copy later */ |
| 981 | PREFETCH_L1(match); |
| 982 | #endif |
| 983 | /* Handle edge cases in a slow path: |
| 984 | * - Read beyond end of literals |
| 985 | * - Match end is within WILDCOPY_OVERLIMIT of oend |
| 986 | * - 32-bit mode and the match length overflows |
| 987 | */ |
| 988 | if (UNLIKELY( |
| 989 | iLitEnd > litLimit || |
| 990 | oMatchEnd > oend_w || |
| 991 | (MEM_32bits() && (size_t)(oend - op) < sequenceLength + WILDCOPY_OVERLENGTH))) |
| 992 | return ZSTD_execSequenceEnd(op, oend, sequence, litPtr, litLimit, prefixStart, virtualStart, dictEnd); |
| 993 | |
| 994 | /* Assumptions (everything else goes into ZSTD_execSequenceEnd()) */ |
| 995 | assert(op <= oLitEnd /* No overflow */); |
| 996 | assert(oLitEnd < oMatchEnd /* Non-zero match & no overflow */); |
| 997 | assert(oMatchEnd <= oend /* No underflow */); |
| 998 | assert(iLitEnd <= litLimit /* Literal length is in bounds */); |
| 999 | assert(oLitEnd <= oend_w /* Can wildcopy literals */); |
| 1000 | assert(oMatchEnd <= oend_w /* Can wildcopy matches */); |
| 1001 | |
| 1002 | /* Copy Literals: |
| 1003 | * Split out litLength <= 16 since it is nearly always true. +1.6% on gcc-9. |
| 1004 | * We likely don't need the full 32-byte wildcopy. |
| 1005 | */ |
| 1006 | assert(WILDCOPY_OVERLENGTH >= 16); |
| 1007 | ZSTD_copy16(op, (*litPtr)); |
| 1008 | if (UNLIKELY(sequence.litLength > 16)) { |
| 1009 | ZSTD_wildcopy(op + 16, (*litPtr) + 16, sequence.litLength - 16, ZSTD_no_overlap); |
| 1010 | } |
| 1011 | op = oLitEnd; |
| 1012 | *litPtr = iLitEnd; /* update for next sequence */ |
| 1013 | |
| 1014 | /* Copy Match */ |
| 1015 | if (sequence.offset > (size_t)(oLitEnd - prefixStart)) { |
| 1016 | /* offset beyond prefix -> go into extDict */ |
| 1017 | RETURN_ERROR_IF(UNLIKELY(sequence.offset > (size_t)(oLitEnd - virtualStart)), corruption_detected, ""); |
| 1018 | match = dictEnd + (match - prefixStart); |
| 1019 | if (match + sequence.matchLength <= dictEnd) { |
| 1020 | ZSTD_memmove(oLitEnd, match, sequence.matchLength); |
| 1021 | return sequenceLength; |
| 1022 | } |
| 1023 | /* span extDict & currentPrefixSegment */ |
| 1024 | { size_t const length1 = dictEnd - match; |
| 1025 | ZSTD_memmove(oLitEnd, match, length1); |
| 1026 | op = oLitEnd + length1; |
| 1027 | sequence.matchLength -= length1; |
| 1028 | match = prefixStart; |
| 1029 | } |
| 1030 | } |
| 1031 | /* Match within prefix of 1 or more bytes */ |
| 1032 | assert(op <= oMatchEnd); |
| 1033 | assert(oMatchEnd <= oend_w); |
| 1034 | assert(match >= prefixStart); |
| 1035 | assert(sequence.matchLength >= 1); |
| 1036 | |
| 1037 | /* Nearly all offsets are >= WILDCOPY_VECLEN bytes, which means we can use wildcopy |
| 1038 | * without overlap checking. |
| 1039 | */ |
| 1040 | if (LIKELY(sequence.offset >= WILDCOPY_VECLEN)) { |
| 1041 | /* We bet on a full wildcopy for matches, since we expect matches to be |
| 1042 | * longer than literals (in general). In silesia, ~10% of matches are longer |
| 1043 | * than 16 bytes. |
| 1044 | */ |
| 1045 | ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength, ZSTD_no_overlap); |
| 1046 | return sequenceLength; |
| 1047 | } |
| 1048 | assert(sequence.offset < WILDCOPY_VECLEN); |
| 1049 | |
| 1050 | /* Copy 8 bytes and spread the offset to be >= 8. */ |
| 1051 | ZSTD_overlapCopy8(&op, &match, sequence.offset); |
| 1052 | |
| 1053 | /* If the match length is > 8 bytes, then continue with the wildcopy. */ |
| 1054 | if (sequence.matchLength > 8) { |
| 1055 | assert(op < oMatchEnd); |
| 1056 | ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength - 8, ZSTD_overlap_src_before_dst); |
| 1057 | } |
| 1058 | return sequenceLength; |
| 1059 | } |
| 1060 | |
| 1061 | HINT_INLINE |
| 1062 | size_t ZSTD_execSequenceSplitLitBuffer(BYTE* op, |
| 1063 | BYTE* const oend, const BYTE* const oend_w, seq_t sequence, |
| 1064 | const BYTE** litPtr, const BYTE* const litLimit, |
| 1065 | const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) |
| 1066 | { |
| 1067 | BYTE* const oLitEnd = op + sequence.litLength; |
| 1068 | size_t const sequenceLength = sequence.litLength + sequence.matchLength; |
| 1069 | BYTE* const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */ |
| 1070 | const BYTE* const iLitEnd = *litPtr + sequence.litLength; |
| 1071 | const BYTE* match = oLitEnd - sequence.offset; |
| 1072 | |
| 1073 | assert(op != NULL /* Precondition */); |
| 1074 | assert(oend_w < oend /* No underflow */); |
| 1075 | /* Handle edge cases in a slow path: |
| 1076 | * - Read beyond end of literals |
| 1077 | * - Match end is within WILDCOPY_OVERLIMIT of oend |
| 1078 | * - 32-bit mode and the match length overflows |
| 1079 | */ |
| 1080 | if (UNLIKELY( |
| 1081 | iLitEnd > litLimit || |
| 1082 | oMatchEnd > oend_w || |
| 1083 | (MEM_32bits() && (size_t)(oend - op) < sequenceLength + WILDCOPY_OVERLENGTH))) |
| 1084 | return ZSTD_execSequenceEndSplitLitBuffer(op, oend, oend_w, sequence, litPtr, litLimit, prefixStart, virtualStart, dictEnd); |
| 1085 | |
| 1086 | /* Assumptions (everything else goes into ZSTD_execSequenceEnd()) */ |
| 1087 | assert(op <= oLitEnd /* No overflow */); |
| 1088 | assert(oLitEnd < oMatchEnd /* Non-zero match & no overflow */); |
| 1089 | assert(oMatchEnd <= oend /* No underflow */); |
| 1090 | assert(iLitEnd <= litLimit /* Literal length is in bounds */); |
| 1091 | assert(oLitEnd <= oend_w /* Can wildcopy literals */); |
| 1092 | assert(oMatchEnd <= oend_w /* Can wildcopy matches */); |
| 1093 | |
| 1094 | /* Copy Literals: |
| 1095 | * Split out litLength <= 16 since it is nearly always true. +1.6% on gcc-9. |
| 1096 | * We likely don't need the full 32-byte wildcopy. |
| 1097 | */ |
| 1098 | assert(WILDCOPY_OVERLENGTH >= 16); |
| 1099 | ZSTD_copy16(op, (*litPtr)); |
| 1100 | if (UNLIKELY(sequence.litLength > 16)) { |
| 1101 | ZSTD_wildcopy(op+16, (*litPtr)+16, sequence.litLength-16, ZSTD_no_overlap); |
| 1102 | } |
| 1103 | op = oLitEnd; |
| 1104 | *litPtr = iLitEnd; /* update for next sequence */ |
| 1105 | |
| 1106 | /* Copy Match */ |
| 1107 | if (sequence.offset > (size_t)(oLitEnd - prefixStart)) { |
| 1108 | /* offset beyond prefix -> go into extDict */ |
| 1109 | RETURN_ERROR_IF(UNLIKELY(sequence.offset > (size_t)(oLitEnd - virtualStart)), corruption_detected, ""); |
| 1110 | match = dictEnd + (match - prefixStart); |
| 1111 | if (match + sequence.matchLength <= dictEnd) { |
| 1112 | ZSTD_memmove(oLitEnd, match, sequence.matchLength); |
| 1113 | return sequenceLength; |
| 1114 | } |
| 1115 | /* span extDict & currentPrefixSegment */ |
| 1116 | { size_t const length1 = dictEnd - match; |
| 1117 | ZSTD_memmove(oLitEnd, match, length1); |
| 1118 | op = oLitEnd + length1; |
| 1119 | sequence.matchLength -= length1; |
| 1120 | match = prefixStart; |
| 1121 | } } |
| 1122 | /* Match within prefix of 1 or more bytes */ |
| 1123 | assert(op <= oMatchEnd); |
| 1124 | assert(oMatchEnd <= oend_w); |
| 1125 | assert(match >= prefixStart); |
| 1126 | assert(sequence.matchLength >= 1); |
| 1127 | |
| 1128 | /* Nearly all offsets are >= WILDCOPY_VECLEN bytes, which means we can use wildcopy |
| 1129 | * without overlap checking. |
| 1130 | */ |
| 1131 | if (LIKELY(sequence.offset >= WILDCOPY_VECLEN)) { |
| 1132 | /* We bet on a full wildcopy for matches, since we expect matches to be |
| 1133 | * longer than literals (in general). In silesia, ~10% of matches are longer |
| 1134 | * than 16 bytes. |
| 1135 | */ |
| 1136 | ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength, ZSTD_no_overlap); |
| 1137 | return sequenceLength; |
| 1138 | } |
| 1139 | assert(sequence.offset < WILDCOPY_VECLEN); |
| 1140 | |
| 1141 | /* Copy 8 bytes and spread the offset to be >= 8. */ |
| 1142 | ZSTD_overlapCopy8(&op, &match, sequence.offset); |
| 1143 | |
| 1144 | /* If the match length is > 8 bytes, then continue with the wildcopy. */ |
| 1145 | if (sequence.matchLength > 8) { |
| 1146 | assert(op < oMatchEnd); |
| 1147 | ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8, ZSTD_overlap_src_before_dst); |
| 1148 | } |
| 1149 | return sequenceLength; |
| 1150 | } |
| 1151 | |
| 1152 | |
| 1153 | static void |
| 1154 | ZSTD_initFseState(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, const ZSTD_seqSymbol* dt) |
| 1155 | { |
| 1156 | const void* ptr = dt; |
| 1157 | const ZSTD_seqSymbol_header* const DTableH = (const ZSTD_seqSymbol_header*)ptr; |
| 1158 | DStatePtr->state = BIT_readBits(bitD, DTableH->tableLog); |
| 1159 | DEBUGLOG(6, "ZSTD_initFseState : val=%u using %u bits", |
| 1160 | (U32)DStatePtr->state, DTableH->tableLog); |
| 1161 | BIT_reloadDStream(bitD); |
| 1162 | DStatePtr->table = dt + 1; |
| 1163 | } |
| 1164 | |
| 1165 | FORCE_INLINE_TEMPLATE void |
| 1166 | ZSTD_updateFseStateWithDInfo(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, U16 nextState, U32 nbBits) |
| 1167 | { |
| 1168 | size_t const lowBits = BIT_readBits(bitD, nbBits); |
| 1169 | DStatePtr->state = nextState + lowBits; |
| 1170 | } |
| 1171 | |
| 1172 | /* We need to add at most (ZSTD_WINDOWLOG_MAX_32 - 1) bits to read the maximum |
| 1173 | * offset bits. But we can only read at most STREAM_ACCUMULATOR_MIN_32 |
| 1174 | * bits before reloading. This value is the maximum number of bytes we read |
| 1175 | * after reloading when we are decoding long offsets. |
| 1176 | */ |
| 1177 | #define LONG_OFFSETS_MAX_EXTRA_BITS_32 \ |
| 1178 | (ZSTD_WINDOWLOG_MAX_32 > STREAM_ACCUMULATOR_MIN_32 \ |
| 1179 | ? ZSTD_WINDOWLOG_MAX_32 - STREAM_ACCUMULATOR_MIN_32 \ |
| 1180 | : 0) |
| 1181 | |
| 1182 | typedef enum { ZSTD_lo_isRegularOffset, ZSTD_lo_isLongOffset=1 } ZSTD_longOffset_e; |
| 1183 | |
| 1184 | FORCE_INLINE_TEMPLATE seq_t |
| 1185 | ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) |
| 1186 | { |
| 1187 | seq_t seq; |
| 1188 | /* |
| 1189 | * ZSTD_seqSymbol is a structure with a total of 64 bits wide. So it can be |
| 1190 | * loaded in one operation and extracted its fields by simply shifting or |
| 1191 | * bit-extracting on aarch64. |
| 1192 | * GCC doesn't recognize this and generates more unnecessary ldr/ldrb/ldrh |
| 1193 | * operations that cause performance drop. This can be avoided by using this |
| 1194 | * ZSTD_memcpy hack. |
| 1195 | */ |
| 1196 | #if defined(__aarch64__) && (defined(__GNUC__) && !defined(__clang__)) |
| 1197 | ZSTD_seqSymbol llDInfoS, mlDInfoS, ofDInfoS; |
| 1198 | ZSTD_seqSymbol* const llDInfo = &llDInfoS; |
| 1199 | ZSTD_seqSymbol* const mlDInfo = &mlDInfoS; |
| 1200 | ZSTD_seqSymbol* const ofDInfo = &ofDInfoS; |
| 1201 | ZSTD_memcpy(llDInfo, seqState->stateLL.table + seqState->stateLL.state, sizeof(ZSTD_seqSymbol)); |
| 1202 | ZSTD_memcpy(mlDInfo, seqState->stateML.table + seqState->stateML.state, sizeof(ZSTD_seqSymbol)); |
| 1203 | ZSTD_memcpy(ofDInfo, seqState->stateOffb.table + seqState->stateOffb.state, sizeof(ZSTD_seqSymbol)); |
| 1204 | #else |
| 1205 | const ZSTD_seqSymbol* const llDInfo = seqState->stateLL.table + seqState->stateLL.state; |
| 1206 | const ZSTD_seqSymbol* const mlDInfo = seqState->stateML.table + seqState->stateML.state; |
| 1207 | const ZSTD_seqSymbol* const ofDInfo = seqState->stateOffb.table + seqState->stateOffb.state; |
| 1208 | #endif |
| 1209 | seq.matchLength = mlDInfo->baseValue; |
| 1210 | seq.litLength = llDInfo->baseValue; |
| 1211 | { U32 const ofBase = ofDInfo->baseValue; |
| 1212 | BYTE const llBits = llDInfo->nbAdditionalBits; |
| 1213 | BYTE const mlBits = mlDInfo->nbAdditionalBits; |
| 1214 | BYTE const ofBits = ofDInfo->nbAdditionalBits; |
| 1215 | BYTE const totalBits = llBits+mlBits+ofBits; |
| 1216 | |
| 1217 | U16 const llNext = llDInfo->nextState; |
| 1218 | U16 const mlNext = mlDInfo->nextState; |
| 1219 | U16 const ofNext = ofDInfo->nextState; |
| 1220 | U32 const llnbBits = llDInfo->nbBits; |
| 1221 | U32 const mlnbBits = mlDInfo->nbBits; |
| 1222 | U32 const ofnbBits = ofDInfo->nbBits; |
| 1223 | |
| 1224 | assert(llBits <= MaxLLBits); |
| 1225 | assert(mlBits <= MaxMLBits); |
| 1226 | assert(ofBits <= MaxOff); |
| 1227 | /* |
| 1228 | * As gcc has better branch and block analyzers, sometimes it is only |
| 1229 | * valuable to mark likeliness for clang, it gives around 3-4% of |
| 1230 | * performance. |
| 1231 | */ |
| 1232 | |
| 1233 | /* sequence */ |
| 1234 | { size_t offset; |
| 1235 | if (ofBits > 1) { |
| 1236 | ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1); |
| 1237 | ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5); |
| 1238 | ZSTD_STATIC_ASSERT(STREAM_ACCUMULATOR_MIN_32 > LONG_OFFSETS_MAX_EXTRA_BITS_32); |
| 1239 | ZSTD_STATIC_ASSERT(STREAM_ACCUMULATOR_MIN_32 - LONG_OFFSETS_MAX_EXTRA_BITS_32 >= MaxMLBits); |
| 1240 | if (MEM_32bits() && longOffsets && (ofBits >= STREAM_ACCUMULATOR_MIN_32)) { |
| 1241 | /* Always read extra bits, this keeps the logic simple, |
| 1242 | * avoids branches, and avoids accidentally reading 0 bits. |
| 1243 | */ |
| 1244 | U32 const extraBits = LONG_OFFSETS_MAX_EXTRA_BITS_32; |
| 1245 | offset = ofBase + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits); |
| 1246 | BIT_reloadDStream(&seqState->DStream); |
| 1247 | offset += BIT_readBitsFast(&seqState->DStream, extraBits); |
| 1248 | } else { |
| 1249 | offset = ofBase + BIT_readBitsFast(&seqState->DStream, ofBits/*>0*/); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */ |
| 1250 | if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); |
| 1251 | } |
| 1252 | seqState->prevOffset[2] = seqState->prevOffset[1]; |
| 1253 | seqState->prevOffset[1] = seqState->prevOffset[0]; |
| 1254 | seqState->prevOffset[0] = offset; |
| 1255 | } else { |
| 1256 | U32 const ll0 = (llDInfo->baseValue == 0); |
| 1257 | if (LIKELY((ofBits == 0))) { |
| 1258 | offset = seqState->prevOffset[ll0]; |
| 1259 | seqState->prevOffset[1] = seqState->prevOffset[!ll0]; |
| 1260 | seqState->prevOffset[0] = offset; |
| 1261 | } else { |
| 1262 | offset = ofBase + ll0 + BIT_readBitsFast(&seqState->DStream, 1); |
| 1263 | { size_t temp = (offset==3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset]; |
| 1264 | temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */ |
| 1265 | if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1]; |
| 1266 | seqState->prevOffset[1] = seqState->prevOffset[0]; |
| 1267 | seqState->prevOffset[0] = offset = temp; |
| 1268 | } } } |
| 1269 | seq.offset = offset; |
| 1270 | } |
| 1271 | |
| 1272 | if (mlBits > 0) |
| 1273 | seq.matchLength += BIT_readBitsFast(&seqState->DStream, mlBits/*>0*/); |
| 1274 | |
| 1275 | if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32)) |
| 1276 | BIT_reloadDStream(&seqState->DStream); |
| 1277 | if (MEM_64bits() && UNLIKELY(totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog))) |
| 1278 | BIT_reloadDStream(&seqState->DStream); |
| 1279 | /* Ensure there are enough bits to read the rest of data in 64-bit mode. */ |
| 1280 | ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64); |
| 1281 | |
| 1282 | if (llBits > 0) |
| 1283 | seq.litLength += BIT_readBitsFast(&seqState->DStream, llBits/*>0*/); |
| 1284 | |
| 1285 | if (MEM_32bits()) |
| 1286 | BIT_reloadDStream(&seqState->DStream); |
| 1287 | |
| 1288 | DEBUGLOG(6, "seq: litL=%u, matchL=%u, offset=%u", |
| 1289 | (U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset); |
| 1290 | |
| 1291 | ZSTD_updateFseStateWithDInfo(&seqState->stateLL, &seqState->DStream, llNext, llnbBits); /* <= 9 bits */ |
| 1292 | ZSTD_updateFseStateWithDInfo(&seqState->stateML, &seqState->DStream, mlNext, mlnbBits); /* <= 9 bits */ |
| 1293 | if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */ |
| 1294 | ZSTD_updateFseStateWithDInfo(&seqState->stateOffb, &seqState->DStream, ofNext, ofnbBits); /* <= 8 bits */ |
| 1295 | } |
| 1296 | |
| 1297 | return seq; |
| 1298 | } |
| 1299 | |
| 1300 | #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION |
| 1301 | MEM_STATIC int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefixStart, BYTE const* oLitEnd) |
| 1302 | { |
| 1303 | size_t const windowSize = dctx->fParams.windowSize; |
| 1304 | /* No dictionary used. */ |
| 1305 | if (dctx->dictContentEndForFuzzing == NULL) return 0; |
| 1306 | /* Dictionary is our prefix. */ |
| 1307 | if (prefixStart == dctx->dictContentBeginForFuzzing) return 1; |
| 1308 | /* Dictionary is not our ext-dict. */ |
| 1309 | if (dctx->dictEnd != dctx->dictContentEndForFuzzing) return 0; |
| 1310 | /* Dictionary is not within our window size. */ |
| 1311 | if ((size_t)(oLitEnd - prefixStart) >= windowSize) return 0; |
| 1312 | /* Dictionary is active. */ |
| 1313 | return 1; |
| 1314 | } |
| 1315 | |
| 1316 | MEM_STATIC void ZSTD_assertValidSequence( |
| 1317 | ZSTD_DCtx const* dctx, |
| 1318 | BYTE const* op, BYTE const* oend, |
| 1319 | seq_t const seq, |
| 1320 | BYTE const* prefixStart, BYTE const* virtualStart) |
| 1321 | { |
| 1322 | #if DEBUGLEVEL >= 1 |
| 1323 | size_t const windowSize = dctx->fParams.windowSize; |
| 1324 | size_t const sequenceSize = seq.litLength + seq.matchLength; |
| 1325 | BYTE const* const oLitEnd = op + seq.litLength; |
| 1326 | DEBUGLOG(6, "Checking sequence: litL=%u matchL=%u offset=%u", |
| 1327 | (U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset); |
| 1328 | assert(op <= oend); |
| 1329 | assert((size_t)(oend - op) >= sequenceSize); |
| 1330 | assert(sequenceSize <= ZSTD_BLOCKSIZE_MAX); |
| 1331 | if (ZSTD_dictionaryIsActive(dctx, prefixStart, oLitEnd)) { |
| 1332 | size_t const dictSize = (size_t)((char const*)dctx->dictContentEndForFuzzing - (char const*)dctx->dictContentBeginForFuzzing); |
| 1333 | /* Offset must be within the dictionary. */ |
| 1334 | assert(seq.offset <= (size_t)(oLitEnd - virtualStart)); |
| 1335 | assert(seq.offset <= windowSize + dictSize); |
| 1336 | } else { |
| 1337 | /* Offset must be within our window. */ |
| 1338 | assert(seq.offset <= windowSize); |
| 1339 | } |
| 1340 | #else |
| 1341 | (void)dctx, (void)op, (void)oend, (void)seq, (void)prefixStart, (void)virtualStart; |
| 1342 | #endif |
| 1343 | } |
| 1344 | #endif |
| 1345 | |
| 1346 | #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG |
| 1347 | |
| 1348 | |
| 1349 | FORCE_INLINE_TEMPLATE size_t |
| 1350 | DONT_VECTORIZE |
| 1351 | ZSTD_decompressSequences_bodySplitLitBuffer( ZSTD_DCtx* dctx, |
| 1352 | void* dst, size_t maxDstSize, |
| 1353 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1354 | const ZSTD_longOffset_e isLongOffset, |
| 1355 | const int frame) |
| 1356 | { |
| 1357 | const BYTE* ip = (const BYTE*)seqStart; |
| 1358 | const BYTE* const iend = ip + seqSize; |
| 1359 | BYTE* const ostart = (BYTE*)dst; |
| 1360 | BYTE* const oend = ostart + maxDstSize; |
| 1361 | BYTE* op = ostart; |
| 1362 | const BYTE* litPtr = dctx->litPtr; |
| 1363 | const BYTE* litBufferEnd = dctx->litBufferEnd; |
| 1364 | const BYTE* const prefixStart = (const BYTE*) (dctx->prefixStart); |
| 1365 | const BYTE* const vBase = (const BYTE*) (dctx->virtualStart); |
| 1366 | const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd); |
| 1367 | DEBUGLOG(5, "ZSTD_decompressSequences_bodySplitLitBuffer"); |
| 1368 | (void)frame; |
| 1369 | |
| 1370 | /* Regen sequences */ |
| 1371 | if (nbSeq) { |
| 1372 | seqState_t seqState; |
| 1373 | dctx->fseEntropy = 1; |
| 1374 | { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; } |
| 1375 | RETURN_ERROR_IF( |
| 1376 | ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend-ip)), |
| 1377 | corruption_detected, ""); |
| 1378 | ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr); |
| 1379 | ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr); |
| 1380 | ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr); |
| 1381 | assert(dst != NULL); |
| 1382 | |
| 1383 | ZSTD_STATIC_ASSERT( |
| 1384 | BIT_DStream_unfinished < BIT_DStream_completed && |
| 1385 | BIT_DStream_endOfBuffer < BIT_DStream_completed && |
| 1386 | BIT_DStream_completed < BIT_DStream_overflow); |
| 1387 | |
| 1388 | /* decompress without overrunning litPtr begins */ |
| 1389 | { |
| 1390 | seq_t sequence = ZSTD_decodeSequence(&seqState, isLongOffset); |
| 1391 | /* Align the decompression loop to 32 + 16 bytes. |
| 1392 | * |
| 1393 | * zstd compiled with gcc-9 on an Intel i9-9900k shows 10% decompression |
| 1394 | * speed swings based on the alignment of the decompression loop. This |
| 1395 | * performance swing is caused by parts of the decompression loop falling |
| 1396 | * out of the DSB. The entire decompression loop should fit in the DSB, |
| 1397 | * when it can't we get much worse performance. You can measure if you've |
| 1398 | * hit the good case or the bad case with this perf command for some |
| 1399 | * compressed file test.zst: |
| 1400 | * |
| 1401 | * perf stat -e cycles -e instructions -e idq.all_dsb_cycles_any_uops \ |
| 1402 | * -e idq.all_mite_cycles_any_uops -- ./zstd -tq test.zst |
| 1403 | * |
| 1404 | * If you see most cycles served out of the MITE you've hit the bad case. |
| 1405 | * If you see most cycles served out of the DSB you've hit the good case. |
| 1406 | * If it is pretty even then you may be in an okay case. |
| 1407 | * |
| 1408 | * This issue has been reproduced on the following CPUs: |
| 1409 | * - Kabylake: Macbook Pro (15-inch, 2019) 2.4 GHz Intel Core i9 |
| 1410 | * Use Instruments->Counters to get DSB/MITE cycles. |
| 1411 | * I never got performance swings, but I was able to |
| 1412 | * go from the good case of mostly DSB to half of the |
| 1413 | * cycles served from MITE. |
| 1414 | * - Coffeelake: Intel i9-9900k |
| 1415 | * - Coffeelake: Intel i7-9700k |
| 1416 | * |
| 1417 | * I haven't been able to reproduce the instability or DSB misses on any |
| 1418 | * of the following CPUS: |
| 1419 | * - Haswell |
| 1420 | * - Broadwell: Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GH |
| 1421 | * - Skylake |
| 1422 | * |
| 1423 | * Alignment is done for each of the three major decompression loops: |
| 1424 | * - ZSTD_decompressSequences_bodySplitLitBuffer - presplit section of the literal buffer |
| 1425 | * - ZSTD_decompressSequences_bodySplitLitBuffer - postsplit section of the literal buffer |
| 1426 | * - ZSTD_decompressSequences_body |
| 1427 | * Alignment choices are made to minimize large swings on bad cases and influence on performance |
| 1428 | * from changes external to this code, rather than to overoptimize on the current commit. |
| 1429 | * |
| 1430 | * If you are seeing performance stability this script can help test. |
| 1431 | * It tests on 4 commits in zstd where I saw performance change. |
| 1432 | * |
| 1433 | * https://gist.github.com/terrelln/9889fc06a423fd5ca6e99351564473f4 |
| 1434 | */ |
| 1435 | #if defined(__GNUC__) && defined(__x86_64__) |
| 1436 | __asm__(".p2align 6"); |
| 1437 | # if __GNUC__ >= 7 |
| 1438 | /* good for gcc-7, gcc-9, and gcc-11 */ |
| 1439 | __asm__("nop"); |
| 1440 | __asm__(".p2align 5"); |
| 1441 | __asm__("nop"); |
| 1442 | __asm__(".p2align 4"); |
| 1443 | # if __GNUC__ == 8 || __GNUC__ == 10 |
| 1444 | /* good for gcc-8 and gcc-10 */ |
| 1445 | __asm__("nop"); |
| 1446 | __asm__(".p2align 3"); |
| 1447 | # endif |
| 1448 | # endif |
| 1449 | #endif |
| 1450 | |
| 1451 | /* Handle the initial state where litBuffer is currently split between dst and litExtraBuffer */ |
| 1452 | for (; litPtr + sequence.litLength <= dctx->litBufferEnd; ) { |
| 1453 | size_t const oneSeqSize = ZSTD_execSequenceSplitLitBuffer(op, oend, litPtr + sequence.litLength - WILDCOPY_OVERLENGTH, sequence, &litPtr, litBufferEnd, prefixStart, vBase, dictEnd); |
| 1454 | #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) |
| 1455 | assert(!ZSTD_isError(oneSeqSize)); |
| 1456 | if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase); |
| 1457 | #endif |
| 1458 | if (UNLIKELY(ZSTD_isError(oneSeqSize))) |
| 1459 | return oneSeqSize; |
| 1460 | DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); |
| 1461 | op += oneSeqSize; |
| 1462 | if (UNLIKELY(!--nbSeq)) |
| 1463 | break; |
| 1464 | BIT_reloadDStream(&(seqState.DStream)); |
| 1465 | sequence = ZSTD_decodeSequence(&seqState, isLongOffset); |
| 1466 | } |
| 1467 | |
| 1468 | /* If there are more sequences, they will need to read literals from litExtraBuffer; copy over the remainder from dst and update litPtr and litEnd */ |
| 1469 | if (nbSeq > 0) { |
| 1470 | const size_t leftoverLit = dctx->litBufferEnd - litPtr; |
| 1471 | if (leftoverLit) |
| 1472 | { |
| 1473 | RETURN_ERROR_IF(leftoverLit > (size_t)(oend - op), dstSize_tooSmall, "remaining lit must fit within dstBuffer"); |
| 1474 | ZSTD_safecopyDstBeforeSrc(op, litPtr, leftoverLit); |
| 1475 | sequence.litLength -= leftoverLit; |
| 1476 | op += leftoverLit; |
| 1477 | } |
| 1478 | litPtr = dctx->litExtraBuffer; |
| 1479 | litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; |
| 1480 | dctx->litBufferLocation = ZSTD_not_in_dst; |
| 1481 | { |
| 1482 | size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litBufferEnd, prefixStart, vBase, dictEnd); |
| 1483 | #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) |
| 1484 | assert(!ZSTD_isError(oneSeqSize)); |
| 1485 | if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase); |
| 1486 | #endif |
| 1487 | if (UNLIKELY(ZSTD_isError(oneSeqSize))) |
| 1488 | return oneSeqSize; |
| 1489 | DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); |
| 1490 | op += oneSeqSize; |
| 1491 | if (--nbSeq) |
| 1492 | BIT_reloadDStream(&(seqState.DStream)); |
| 1493 | } |
| 1494 | } |
| 1495 | } |
| 1496 | |
| 1497 | if (nbSeq > 0) /* there is remaining lit from extra buffer */ |
| 1498 | { |
| 1499 | |
| 1500 | #if defined(__GNUC__) && defined(__x86_64__) |
| 1501 | __asm__(".p2align 6"); |
| 1502 | __asm__("nop"); |
| 1503 | # if __GNUC__ != 7 |
| 1504 | /* worse for gcc-7 better for gcc-8, gcc-9, and gcc-10 and clang */ |
| 1505 | __asm__(".p2align 4"); |
| 1506 | __asm__("nop"); |
| 1507 | __asm__(".p2align 3"); |
| 1508 | # elif __GNUC__ >= 11 |
| 1509 | __asm__(".p2align 3"); |
| 1510 | # else |
| 1511 | __asm__(".p2align 5"); |
| 1512 | __asm__("nop"); |
| 1513 | __asm__(".p2align 3"); |
| 1514 | # endif |
| 1515 | #endif |
| 1516 | |
| 1517 | for (; ; ) { |
| 1518 | seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); |
| 1519 | size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litBufferEnd, prefixStart, vBase, dictEnd); |
| 1520 | #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) |
| 1521 | assert(!ZSTD_isError(oneSeqSize)); |
| 1522 | if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase); |
| 1523 | #endif |
| 1524 | if (UNLIKELY(ZSTD_isError(oneSeqSize))) |
| 1525 | return oneSeqSize; |
| 1526 | DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); |
| 1527 | op += oneSeqSize; |
| 1528 | if (UNLIKELY(!--nbSeq)) |
| 1529 | break; |
| 1530 | BIT_reloadDStream(&(seqState.DStream)); |
| 1531 | } |
| 1532 | } |
| 1533 | |
| 1534 | /* check if reached exact end */ |
| 1535 | DEBUGLOG(5, "ZSTD_decompressSequences_bodySplitLitBuffer: after decode loop, remaining nbSeq : %i", nbSeq); |
| 1536 | RETURN_ERROR_IF(nbSeq, corruption_detected, ""); |
| 1537 | RETURN_ERROR_IF(BIT_reloadDStream(&seqState.DStream) < BIT_DStream_completed, corruption_detected, ""); |
| 1538 | /* save reps for next block */ |
| 1539 | { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); } |
| 1540 | } |
| 1541 | |
| 1542 | /* last literal segment */ |
| 1543 | if (dctx->litBufferLocation == ZSTD_split) /* split hasn't been reached yet, first get dst then copy litExtraBuffer */ |
| 1544 | { |
| 1545 | size_t const lastLLSize = litBufferEnd - litPtr; |
| 1546 | RETURN_ERROR_IF(lastLLSize > (size_t)(oend - op), dstSize_tooSmall, ""); |
| 1547 | if (op != NULL) { |
| 1548 | ZSTD_memmove(op, litPtr, lastLLSize); |
| 1549 | op += lastLLSize; |
| 1550 | } |
| 1551 | litPtr = dctx->litExtraBuffer; |
| 1552 | litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; |
| 1553 | dctx->litBufferLocation = ZSTD_not_in_dst; |
| 1554 | } |
| 1555 | { size_t const lastLLSize = litBufferEnd - litPtr; |
| 1556 | RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, ""); |
| 1557 | if (op != NULL) { |
| 1558 | ZSTD_memcpy(op, litPtr, lastLLSize); |
| 1559 | op += lastLLSize; |
| 1560 | } |
| 1561 | } |
| 1562 | |
| 1563 | return op-ostart; |
| 1564 | } |
| 1565 | |
| 1566 | FORCE_INLINE_TEMPLATE size_t |
| 1567 | DONT_VECTORIZE |
| 1568 | ZSTD_decompressSequences_body(ZSTD_DCtx* dctx, |
| 1569 | void* dst, size_t maxDstSize, |
| 1570 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1571 | const ZSTD_longOffset_e isLongOffset, |
| 1572 | const int frame) |
| 1573 | { |
| 1574 | const BYTE* ip = (const BYTE*)seqStart; |
| 1575 | const BYTE* const iend = ip + seqSize; |
| 1576 | BYTE* const ostart = (BYTE*)dst; |
| 1577 | BYTE* const oend = dctx->litBufferLocation == ZSTD_not_in_dst ? ostart + maxDstSize : dctx->litBuffer; |
| 1578 | BYTE* op = ostart; |
| 1579 | const BYTE* litPtr = dctx->litPtr; |
| 1580 | const BYTE* const litEnd = litPtr + dctx->litSize; |
| 1581 | const BYTE* const prefixStart = (const BYTE*)(dctx->prefixStart); |
| 1582 | const BYTE* const vBase = (const BYTE*)(dctx->virtualStart); |
| 1583 | const BYTE* const dictEnd = (const BYTE*)(dctx->dictEnd); |
| 1584 | DEBUGLOG(5, "ZSTD_decompressSequences_body: nbSeq = %d", nbSeq); |
| 1585 | (void)frame; |
| 1586 | |
| 1587 | /* Regen sequences */ |
| 1588 | if (nbSeq) { |
| 1589 | seqState_t seqState; |
| 1590 | dctx->fseEntropy = 1; |
| 1591 | { U32 i; for (i = 0; i < ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; } |
| 1592 | RETURN_ERROR_IF( |
| 1593 | ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend - ip)), |
| 1594 | corruption_detected, ""); |
| 1595 | ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr); |
| 1596 | ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr); |
| 1597 | ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr); |
| 1598 | assert(dst != NULL); |
| 1599 | |
| 1600 | ZSTD_STATIC_ASSERT( |
| 1601 | BIT_DStream_unfinished < BIT_DStream_completed && |
| 1602 | BIT_DStream_endOfBuffer < BIT_DStream_completed && |
| 1603 | BIT_DStream_completed < BIT_DStream_overflow); |
| 1604 | |
| 1605 | #if defined(__GNUC__) && defined(__x86_64__) |
| 1606 | __asm__(".p2align 6"); |
| 1607 | __asm__("nop"); |
| 1608 | # if __GNUC__ >= 7 |
| 1609 | __asm__(".p2align 5"); |
| 1610 | __asm__("nop"); |
| 1611 | __asm__(".p2align 3"); |
| 1612 | # else |
| 1613 | __asm__(".p2align 4"); |
| 1614 | __asm__("nop"); |
| 1615 | __asm__(".p2align 3"); |
| 1616 | # endif |
| 1617 | #endif |
| 1618 | |
| 1619 | for ( ; ; ) { |
| 1620 | seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); |
| 1621 | size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, prefixStart, vBase, dictEnd); |
| 1622 | #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) |
| 1623 | assert(!ZSTD_isError(oneSeqSize)); |
| 1624 | if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase); |
| 1625 | #endif |
| 1626 | if (UNLIKELY(ZSTD_isError(oneSeqSize))) |
| 1627 | return oneSeqSize; |
| 1628 | DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); |
| 1629 | op += oneSeqSize; |
| 1630 | if (UNLIKELY(!--nbSeq)) |
| 1631 | break; |
| 1632 | BIT_reloadDStream(&(seqState.DStream)); |
| 1633 | } |
| 1634 | |
| 1635 | /* check if reached exact end */ |
| 1636 | DEBUGLOG(5, "ZSTD_decompressSequences_body: after decode loop, remaining nbSeq : %i", nbSeq); |
| 1637 | RETURN_ERROR_IF(nbSeq, corruption_detected, ""); |
| 1638 | RETURN_ERROR_IF(BIT_reloadDStream(&seqState.DStream) < BIT_DStream_completed, corruption_detected, ""); |
| 1639 | /* save reps for next block */ |
| 1640 | { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); } |
| 1641 | } |
| 1642 | |
| 1643 | /* last literal segment */ |
| 1644 | { size_t const lastLLSize = litEnd - litPtr; |
| 1645 | RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, ""); |
| 1646 | if (op != NULL) { |
| 1647 | ZSTD_memcpy(op, litPtr, lastLLSize); |
| 1648 | op += lastLLSize; |
| 1649 | } |
| 1650 | } |
| 1651 | |
| 1652 | return op-ostart; |
| 1653 | } |
| 1654 | |
| 1655 | static size_t |
| 1656 | ZSTD_decompressSequences_default(ZSTD_DCtx* dctx, |
| 1657 | void* dst, size_t maxDstSize, |
| 1658 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1659 | const ZSTD_longOffset_e isLongOffset, |
| 1660 | const int frame) |
| 1661 | { |
| 1662 | return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1663 | } |
| 1664 | |
| 1665 | static size_t |
| 1666 | ZSTD_decompressSequencesSplitLitBuffer_default(ZSTD_DCtx* dctx, |
| 1667 | void* dst, size_t maxDstSize, |
| 1668 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1669 | const ZSTD_longOffset_e isLongOffset, |
| 1670 | const int frame) |
| 1671 | { |
| 1672 | return ZSTD_decompressSequences_bodySplitLitBuffer(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1673 | } |
| 1674 | #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */ |
| 1675 | |
| 1676 | #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT |
| 1677 | |
| 1678 | FORCE_INLINE_TEMPLATE size_t |
| 1679 | ZSTD_prefetchMatch(size_t prefetchPos, seq_t const sequence, |
| 1680 | const BYTE* const prefixStart, const BYTE* const dictEnd) |
| 1681 | { |
| 1682 | prefetchPos += sequence.litLength; |
| 1683 | { const BYTE* const matchBase = (sequence.offset > prefetchPos) ? dictEnd : prefixStart; |
| 1684 | const BYTE* const match = matchBase + prefetchPos - sequence.offset; /* note : this operation can overflow when seq.offset is really too large, which can only happen when input is corrupted. |
| 1685 | * No consequence though : memory address is only used for prefetching, not for dereferencing */ |
| 1686 | PREFETCH_L1(match); PREFETCH_L1(match+CACHELINE_SIZE); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */ |
| 1687 | } |
| 1688 | return prefetchPos + sequence.matchLength; |
| 1689 | } |
| 1690 | |
| 1691 | /* This decoding function employs prefetching |
| 1692 | * to reduce latency impact of cache misses. |
| 1693 | * It's generally employed when block contains a significant portion of long-distance matches |
| 1694 | * or when coupled with a "cold" dictionary */ |
| 1695 | FORCE_INLINE_TEMPLATE size_t |
| 1696 | ZSTD_decompressSequencesLong_body( |
| 1697 | ZSTD_DCtx* dctx, |
| 1698 | void* dst, size_t maxDstSize, |
| 1699 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1700 | const ZSTD_longOffset_e isLongOffset, |
| 1701 | const int frame) |
| 1702 | { |
| 1703 | const BYTE* ip = (const BYTE*)seqStart; |
| 1704 | const BYTE* const iend = ip + seqSize; |
| 1705 | BYTE* const ostart = (BYTE*)dst; |
| 1706 | BYTE* const oend = dctx->litBufferLocation == ZSTD_in_dst ? dctx->litBuffer : ostart + maxDstSize; |
| 1707 | BYTE* op = ostart; |
| 1708 | const BYTE* litPtr = dctx->litPtr; |
| 1709 | const BYTE* litBufferEnd = dctx->litBufferEnd; |
| 1710 | const BYTE* const prefixStart = (const BYTE*) (dctx->prefixStart); |
| 1711 | const BYTE* const dictStart = (const BYTE*) (dctx->virtualStart); |
| 1712 | const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd); |
| 1713 | (void)frame; |
| 1714 | |
| 1715 | /* Regen sequences */ |
| 1716 | if (nbSeq) { |
| 1717 | #define STORED_SEQS 8 |
| 1718 | #define STORED_SEQS_MASK (STORED_SEQS-1) |
| 1719 | #define ADVANCED_SEQS STORED_SEQS |
| 1720 | seq_t sequences[STORED_SEQS]; |
| 1721 | int const seqAdvance = MIN(nbSeq, ADVANCED_SEQS); |
| 1722 | seqState_t seqState; |
| 1723 | int seqNb; |
| 1724 | size_t prefetchPos = (size_t)(op-prefixStart); /* track position relative to prefixStart */ |
| 1725 | |
| 1726 | dctx->fseEntropy = 1; |
| 1727 | { int i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; } |
| 1728 | assert(dst != NULL); |
| 1729 | assert(iend >= ip); |
| 1730 | RETURN_ERROR_IF( |
| 1731 | ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend-ip)), |
| 1732 | corruption_detected, ""); |
| 1733 | ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr); |
| 1734 | ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr); |
| 1735 | ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr); |
| 1736 | |
| 1737 | /* prepare in advance */ |
| 1738 | for (seqNb=0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && (seqNb<seqAdvance); seqNb++) { |
| 1739 | seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); |
| 1740 | prefetchPos = ZSTD_prefetchMatch(prefetchPos, sequence, prefixStart, dictEnd); |
| 1741 | sequences[seqNb] = sequence; |
| 1742 | } |
| 1743 | RETURN_ERROR_IF(seqNb<seqAdvance, corruption_detected, ""); |
| 1744 | |
| 1745 | /* decompress without stomping litBuffer */ |
| 1746 | for (; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && (seqNb < nbSeq); seqNb++) { |
| 1747 | seq_t sequence = ZSTD_decodeSequence(&seqState, isLongOffset); |
| 1748 | size_t oneSeqSize; |
| 1749 | |
| 1750 | if (dctx->litBufferLocation == ZSTD_split && litPtr + sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK].litLength > dctx->litBufferEnd) |
| 1751 | { |
| 1752 | /* lit buffer is reaching split point, empty out the first buffer and transition to litExtraBuffer */ |
| 1753 | const size_t leftoverLit = dctx->litBufferEnd - litPtr; |
| 1754 | if (leftoverLit) |
| 1755 | { |
| 1756 | RETURN_ERROR_IF(leftoverLit > (size_t)(oend - op), dstSize_tooSmall, "remaining lit must fit within dstBuffer"); |
| 1757 | ZSTD_safecopyDstBeforeSrc(op, litPtr, leftoverLit); |
| 1758 | sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK].litLength -= leftoverLit; |
| 1759 | op += leftoverLit; |
| 1760 | } |
| 1761 | litPtr = dctx->litExtraBuffer; |
| 1762 | litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; |
| 1763 | dctx->litBufferLocation = ZSTD_not_in_dst; |
| 1764 | oneSeqSize = ZSTD_execSequence(op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd); |
| 1765 | #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) |
| 1766 | assert(!ZSTD_isError(oneSeqSize)); |
| 1767 | if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], prefixStart, dictStart); |
| 1768 | #endif |
| 1769 | if (ZSTD_isError(oneSeqSize)) return oneSeqSize; |
| 1770 | |
| 1771 | prefetchPos = ZSTD_prefetchMatch(prefetchPos, sequence, prefixStart, dictEnd); |
| 1772 | sequences[seqNb & STORED_SEQS_MASK] = sequence; |
| 1773 | op += oneSeqSize; |
| 1774 | } |
| 1775 | else |
| 1776 | { |
| 1777 | /* lit buffer is either wholly contained in first or second split, or not split at all*/ |
| 1778 | oneSeqSize = dctx->litBufferLocation == ZSTD_split ? |
| 1779 | ZSTD_execSequenceSplitLitBuffer(op, oend, litPtr + sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK].litLength - WILDCOPY_OVERLENGTH, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd) : |
| 1780 | ZSTD_execSequence(op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd); |
| 1781 | #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) |
| 1782 | assert(!ZSTD_isError(oneSeqSize)); |
| 1783 | if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], prefixStart, dictStart); |
| 1784 | #endif |
| 1785 | if (ZSTD_isError(oneSeqSize)) return oneSeqSize; |
| 1786 | |
| 1787 | prefetchPos = ZSTD_prefetchMatch(prefetchPos, sequence, prefixStart, dictEnd); |
| 1788 | sequences[seqNb & STORED_SEQS_MASK] = sequence; |
| 1789 | op += oneSeqSize; |
| 1790 | } |
| 1791 | } |
| 1792 | RETURN_ERROR_IF(seqNb<nbSeq, corruption_detected, ""); |
| 1793 | |
| 1794 | /* finish queue */ |
| 1795 | seqNb -= seqAdvance; |
| 1796 | for ( ; seqNb<nbSeq ; seqNb++) { |
| 1797 | seq_t *sequence = &(sequences[seqNb&STORED_SEQS_MASK]); |
| 1798 | if (dctx->litBufferLocation == ZSTD_split && litPtr + sequence->litLength > dctx->litBufferEnd) |
| 1799 | { |
| 1800 | const size_t leftoverLit = dctx->litBufferEnd - litPtr; |
| 1801 | if (leftoverLit) |
| 1802 | { |
| 1803 | RETURN_ERROR_IF(leftoverLit > (size_t)(oend - op), dstSize_tooSmall, "remaining lit must fit within dstBuffer"); |
| 1804 | ZSTD_safecopyDstBeforeSrc(op, litPtr, leftoverLit); |
| 1805 | sequence->litLength -= leftoverLit; |
| 1806 | op += leftoverLit; |
| 1807 | } |
| 1808 | litPtr = dctx->litExtraBuffer; |
| 1809 | litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; |
| 1810 | dctx->litBufferLocation = ZSTD_not_in_dst; |
| 1811 | { |
| 1812 | size_t const oneSeqSize = ZSTD_execSequence(op, oend, *sequence, &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd); |
| 1813 | #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) |
| 1814 | assert(!ZSTD_isError(oneSeqSize)); |
| 1815 | if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[seqNb&STORED_SEQS_MASK], prefixStart, dictStart); |
| 1816 | #endif |
| 1817 | if (ZSTD_isError(oneSeqSize)) return oneSeqSize; |
| 1818 | op += oneSeqSize; |
| 1819 | } |
| 1820 | } |
| 1821 | else |
| 1822 | { |
| 1823 | size_t const oneSeqSize = dctx->litBufferLocation == ZSTD_split ? |
| 1824 | ZSTD_execSequenceSplitLitBuffer(op, oend, litPtr + sequence->litLength - WILDCOPY_OVERLENGTH, *sequence, &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd) : |
| 1825 | ZSTD_execSequence(op, oend, *sequence, &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd); |
| 1826 | #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) |
| 1827 | assert(!ZSTD_isError(oneSeqSize)); |
| 1828 | if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[seqNb&STORED_SEQS_MASK], prefixStart, dictStart); |
| 1829 | #endif |
| 1830 | if (ZSTD_isError(oneSeqSize)) return oneSeqSize; |
| 1831 | op += oneSeqSize; |
| 1832 | } |
| 1833 | } |
| 1834 | |
| 1835 | /* save reps for next block */ |
| 1836 | { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); } |
| 1837 | } |
| 1838 | |
| 1839 | /* last literal segment */ |
| 1840 | if (dctx->litBufferLocation == ZSTD_split) /* first deplete literal buffer in dst, then copy litExtraBuffer */ |
| 1841 | { |
| 1842 | size_t const lastLLSize = litBufferEnd - litPtr; |
| 1843 | RETURN_ERROR_IF(lastLLSize > (size_t)(oend - op), dstSize_tooSmall, ""); |
| 1844 | if (op != NULL) { |
| 1845 | ZSTD_memmove(op, litPtr, lastLLSize); |
| 1846 | op += lastLLSize; |
| 1847 | } |
| 1848 | litPtr = dctx->litExtraBuffer; |
| 1849 | litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; |
| 1850 | } |
| 1851 | { size_t const lastLLSize = litBufferEnd - litPtr; |
| 1852 | RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, ""); |
| 1853 | if (op != NULL) { |
| 1854 | ZSTD_memmove(op, litPtr, lastLLSize); |
| 1855 | op += lastLLSize; |
| 1856 | } |
| 1857 | } |
| 1858 | |
| 1859 | return op-ostart; |
| 1860 | } |
| 1861 | |
| 1862 | static size_t |
| 1863 | ZSTD_decompressSequencesLong_default(ZSTD_DCtx* dctx, |
| 1864 | void* dst, size_t maxDstSize, |
| 1865 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1866 | const ZSTD_longOffset_e isLongOffset, |
| 1867 | const int frame) |
| 1868 | { |
| 1869 | return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1870 | } |
| 1871 | #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */ |
| 1872 | |
| 1873 | |
| 1874 | |
| 1875 | #if DYNAMIC_BMI2 |
| 1876 | |
| 1877 | #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG |
| 1878 | static BMI2_TARGET_ATTRIBUTE size_t |
| 1879 | DONT_VECTORIZE |
| 1880 | ZSTD_decompressSequences_bmi2(ZSTD_DCtx* dctx, |
| 1881 | void* dst, size_t maxDstSize, |
| 1882 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1883 | const ZSTD_longOffset_e isLongOffset, |
| 1884 | const int frame) |
| 1885 | { |
| 1886 | return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1887 | } |
| 1888 | static BMI2_TARGET_ATTRIBUTE size_t |
| 1889 | DONT_VECTORIZE |
| 1890 | ZSTD_decompressSequencesSplitLitBuffer_bmi2(ZSTD_DCtx* dctx, |
| 1891 | void* dst, size_t maxDstSize, |
| 1892 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1893 | const ZSTD_longOffset_e isLongOffset, |
| 1894 | const int frame) |
| 1895 | { |
| 1896 | return ZSTD_decompressSequences_bodySplitLitBuffer(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1897 | } |
| 1898 | #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */ |
| 1899 | |
| 1900 | #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT |
| 1901 | static BMI2_TARGET_ATTRIBUTE size_t |
| 1902 | ZSTD_decompressSequencesLong_bmi2(ZSTD_DCtx* dctx, |
| 1903 | void* dst, size_t maxDstSize, |
| 1904 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1905 | const ZSTD_longOffset_e isLongOffset, |
| 1906 | const int frame) |
| 1907 | { |
| 1908 | return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1909 | } |
| 1910 | #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */ |
| 1911 | |
| 1912 | #endif /* DYNAMIC_BMI2 */ |
| 1913 | |
| 1914 | typedef size_t (*ZSTD_decompressSequences_t)( |
| 1915 | ZSTD_DCtx* dctx, |
| 1916 | void* dst, size_t maxDstSize, |
| 1917 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1918 | const ZSTD_longOffset_e isLongOffset, |
| 1919 | const int frame); |
| 1920 | |
| 1921 | #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG |
| 1922 | static size_t |
| 1923 | ZSTD_decompressSequences(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, |
| 1924 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1925 | const ZSTD_longOffset_e isLongOffset, |
| 1926 | const int frame) |
| 1927 | { |
| 1928 | DEBUGLOG(5, "ZSTD_decompressSequences"); |
| 1929 | #if DYNAMIC_BMI2 |
| 1930 | if (ZSTD_DCtx_get_bmi2(dctx)) { |
| 1931 | return ZSTD_decompressSequences_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1932 | } |
| 1933 | #endif |
| 1934 | return ZSTD_decompressSequences_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1935 | } |
| 1936 | static size_t |
| 1937 | ZSTD_decompressSequencesSplitLitBuffer(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, |
| 1938 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1939 | const ZSTD_longOffset_e isLongOffset, |
| 1940 | const int frame) |
| 1941 | { |
| 1942 | DEBUGLOG(5, "ZSTD_decompressSequencesSplitLitBuffer"); |
| 1943 | #if DYNAMIC_BMI2 |
| 1944 | if (ZSTD_DCtx_get_bmi2(dctx)) { |
| 1945 | return ZSTD_decompressSequencesSplitLitBuffer_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1946 | } |
| 1947 | #endif |
| 1948 | return ZSTD_decompressSequencesSplitLitBuffer_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1949 | } |
| 1950 | #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */ |
| 1951 | |
| 1952 | |
| 1953 | #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT |
| 1954 | /* ZSTD_decompressSequencesLong() : |
| 1955 | * decompression function triggered when a minimum share of offsets is considered "long", |
| 1956 | * aka out of cache. |
| 1957 | * note : "long" definition seems overloaded here, sometimes meaning "wider than bitstream register", and sometimes meaning "farther than memory cache distance". |
| 1958 | * This function will try to mitigate main memory latency through the use of prefetching */ |
| 1959 | static size_t |
| 1960 | ZSTD_decompressSequencesLong(ZSTD_DCtx* dctx, |
| 1961 | void* dst, size_t maxDstSize, |
| 1962 | const void* seqStart, size_t seqSize, int nbSeq, |
| 1963 | const ZSTD_longOffset_e isLongOffset, |
| 1964 | const int frame) |
| 1965 | { |
| 1966 | DEBUGLOG(5, "ZSTD_decompressSequencesLong"); |
| 1967 | #if DYNAMIC_BMI2 |
| 1968 | if (ZSTD_DCtx_get_bmi2(dctx)) { |
| 1969 | return ZSTD_decompressSequencesLong_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1970 | } |
| 1971 | #endif |
| 1972 | return ZSTD_decompressSequencesLong_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); |
| 1973 | } |
| 1974 | #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */ |
| 1975 | |
| 1976 | |
| 1977 | /** |
| 1978 | * @returns The total size of the history referenceable by zstd, including |
| 1979 | * both the prefix and the extDict. At @p op any offset larger than this |
| 1980 | * is invalid. |
| 1981 | */ |
| 1982 | static size_t ZSTD_totalHistorySize(BYTE* op, BYTE const* virtualStart) |
| 1983 | { |
| 1984 | return (size_t)(op - virtualStart); |
| 1985 | } |
| 1986 | |
| 1987 | typedef struct { |
| 1988 | unsigned longOffsetShare; |
| 1989 | unsigned maxNbAdditionalBits; |
| 1990 | } ZSTD_OffsetInfo; |
| 1991 | |
| 1992 | /* ZSTD_getOffsetInfo() : |
| 1993 | * condition : offTable must be valid |
| 1994 | * @return : "share" of long offsets (arbitrarily defined as > (1<<23)) |
| 1995 | * compared to maximum possible of (1<<OffFSELog), |
| 1996 | * as well as the maximum number additional bits required. |
| 1997 | */ |
| 1998 | static ZSTD_OffsetInfo |
| 1999 | ZSTD_getOffsetInfo(const ZSTD_seqSymbol* offTable, int nbSeq) |
| 2000 | { |
| 2001 | ZSTD_OffsetInfo info = {0, 0}; |
| 2002 | /* If nbSeq == 0, then the offTable is uninitialized, but we have |
| 2003 | * no sequences, so both values should be 0. |
| 2004 | */ |
| 2005 | if (nbSeq != 0) { |
| 2006 | const void* ptr = offTable; |
| 2007 | U32 const tableLog = ((const ZSTD_seqSymbol_header*)ptr)[0].tableLog; |
| 2008 | const ZSTD_seqSymbol* table = offTable + 1; |
| 2009 | U32 const max = 1 << tableLog; |
| 2010 | U32 u; |
| 2011 | DEBUGLOG(5, "ZSTD_getLongOffsetsShare: (tableLog=%u)", tableLog); |
| 2012 | |
| 2013 | assert(max <= (1 << OffFSELog)); /* max not too large */ |
| 2014 | for (u=0; u<max; u++) { |
| 2015 | info.maxNbAdditionalBits = MAX(info.maxNbAdditionalBits, table[u].nbAdditionalBits); |
| 2016 | if (table[u].nbAdditionalBits > 22) info.longOffsetShare += 1; |
| 2017 | } |
| 2018 | |
| 2019 | assert(tableLog <= OffFSELog); |
| 2020 | info.longOffsetShare <<= (OffFSELog - tableLog); /* scale to OffFSELog */ |
| 2021 | } |
| 2022 | |
| 2023 | return info; |
| 2024 | } |
| 2025 | |
| 2026 | /** |
| 2027 | * @returns The maximum offset we can decode in one read of our bitstream, without |
| 2028 | * reloading more bits in the middle of the offset bits read. Any offsets larger |
| 2029 | * than this must use the long offset decoder. |
| 2030 | */ |
| 2031 | static size_t ZSTD_maxShortOffset(void) |
| 2032 | { |
| 2033 | if (MEM_64bits()) { |
| 2034 | /* We can decode any offset without reloading bits. |
| 2035 | * This might change if the max window size grows. |
| 2036 | */ |
| 2037 | ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX <= 31); |
| 2038 | return (size_t)-1; |
| 2039 | } else { |
| 2040 | /* The maximum offBase is (1 << (STREAM_ACCUMULATOR_MIN + 1)) - 1. |
| 2041 | * This offBase would require STREAM_ACCUMULATOR_MIN extra bits. |
| 2042 | * Then we have to subtract ZSTD_REP_NUM to get the maximum possible offset. |
| 2043 | */ |
| 2044 | size_t const maxOffbase = ((size_t)1 << (STREAM_ACCUMULATOR_MIN + 1)) - 1; |
| 2045 | size_t const maxOffset = maxOffbase - ZSTD_REP_NUM; |
| 2046 | assert(ZSTD_highbit32((U32)maxOffbase) == STREAM_ACCUMULATOR_MIN); |
| 2047 | return maxOffset; |
| 2048 | } |
| 2049 | } |
| 2050 | |
| 2051 | size_t |
| 2052 | ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx, |
| 2053 | void* dst, size_t dstCapacity, |
| 2054 | const void* src, size_t srcSize, const int frame, const streaming_operation streaming) |
| 2055 | { /* blockType == blockCompressed */ |
| 2056 | const BYTE* ip = (const BYTE*)src; |
| 2057 | DEBUGLOG(5, "ZSTD_decompressBlock_internal (size : %u)", (U32)srcSize); |
| 2058 | |
| 2059 | /* Note : the wording of the specification |
| 2060 | * allows compressed block to be sized exactly ZSTD_BLOCKSIZE_MAX. |
| 2061 | * This generally does not happen, as it makes little sense, |
| 2062 | * since an uncompressed block would feature same size and have no decompression cost. |
| 2063 | * Also, note that decoder from reference libzstd before < v1.5.4 |
| 2064 | * would consider this edge case as an error. |
| 2065 | * As a consequence, avoid generating compressed blocks of size ZSTD_BLOCKSIZE_MAX |
| 2066 | * for broader compatibility with the deployed ecosystem of zstd decoders */ |
| 2067 | RETURN_ERROR_IF(srcSize > ZSTD_BLOCKSIZE_MAX, srcSize_wrong, ""); |
| 2068 | |
| 2069 | /* Decode literals section */ |
| 2070 | { size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize, dst, dstCapacity, streaming); |
| 2071 | DEBUGLOG(5, "ZSTD_decodeLiteralsBlock : cSize=%u, nbLiterals=%zu", (U32)litCSize, dctx->litSize); |
| 2072 | if (ZSTD_isError(litCSize)) return litCSize; |
| 2073 | ip += litCSize; |
| 2074 | srcSize -= litCSize; |
| 2075 | } |
| 2076 | |
| 2077 | /* Build Decoding Tables */ |
| 2078 | { |
| 2079 | /* Compute the maximum block size, which must also work when !frame and fParams are unset. |
| 2080 | * Additionally, take the min with dstCapacity to ensure that the totalHistorySize fits in a size_t. |
| 2081 | */ |
| 2082 | size_t const blockSizeMax = MIN(dstCapacity, (frame ? dctx->fParams.blockSizeMax : ZSTD_BLOCKSIZE_MAX)); |
| 2083 | size_t const totalHistorySize = ZSTD_totalHistorySize((BYTE*)dst + blockSizeMax, (BYTE const*)dctx->virtualStart); |
| 2084 | /* isLongOffset must be true if there are long offsets. |
| 2085 | * Offsets are long if they are larger than ZSTD_maxShortOffset(). |
| 2086 | * We don't expect that to be the case in 64-bit mode. |
| 2087 | * |
| 2088 | * We check here to see if our history is large enough to allow long offsets. |
| 2089 | * If it isn't, then we can't possible have (valid) long offsets. If the offset |
| 2090 | * is invalid, then it is okay to read it incorrectly. |
| 2091 | * |
| 2092 | * If isLongOffsets is true, then we will later check our decoding table to see |
| 2093 | * if it is even possible to generate long offsets. |
| 2094 | */ |
| 2095 | ZSTD_longOffset_e isLongOffset = (ZSTD_longOffset_e)(MEM_32bits() && (totalHistorySize > ZSTD_maxShortOffset())); |
| 2096 | /* These macros control at build-time which decompressor implementation |
| 2097 | * we use. If neither is defined, we do some inspection and dispatch at |
| 2098 | * runtime. |
| 2099 | */ |
| 2100 | #if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \ |
| 2101 | !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG) |
| 2102 | int usePrefetchDecoder = dctx->ddictIsCold; |
| 2103 | #else |
| 2104 | /* Set to 1 to avoid computing offset info if we don't need to. |
| 2105 | * Otherwise this value is ignored. |
| 2106 | */ |
| 2107 | int usePrefetchDecoder = 1; |
| 2108 | #endif |
| 2109 | int nbSeq; |
| 2110 | size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, srcSize); |
| 2111 | if (ZSTD_isError(seqHSize)) return seqHSize; |
| 2112 | ip += seqHSize; |
| 2113 | srcSize -= seqHSize; |
| 2114 | |
| 2115 | RETURN_ERROR_IF((dst == NULL || dstCapacity == 0) && nbSeq > 0, dstSize_tooSmall, "NULL not handled"); |
| 2116 | RETURN_ERROR_IF(MEM_64bits() && sizeof(size_t) == sizeof(void*) && (size_t)(-1) - (size_t)dst < (size_t)(1 << 20), dstSize_tooSmall, |
| 2117 | "invalid dst"); |
| 2118 | |
| 2119 | /* If we could potentially have long offsets, or we might want to use the prefetch decoder, |
| 2120 | * compute information about the share of long offsets, and the maximum nbAdditionalBits. |
| 2121 | * NOTE: could probably use a larger nbSeq limit |
| 2122 | */ |
| 2123 | if (isLongOffset || (!usePrefetchDecoder && (totalHistorySize > (1u << 24)) && (nbSeq > 8))) { |
| 2124 | ZSTD_OffsetInfo const info = ZSTD_getOffsetInfo(dctx->OFTptr, nbSeq); |
| 2125 | if (isLongOffset && info.maxNbAdditionalBits <= STREAM_ACCUMULATOR_MIN) { |
| 2126 | /* If isLongOffset, but the maximum number of additional bits that we see in our table is small |
| 2127 | * enough, then we know it is impossible to have too long an offset in this block, so we can |
| 2128 | * use the regular offset decoder. |
| 2129 | */ |
| 2130 | isLongOffset = ZSTD_lo_isRegularOffset; |
| 2131 | } |
| 2132 | if (!usePrefetchDecoder) { |
| 2133 | U32 const minShare = MEM_64bits() ? 7 : 20; /* heuristic values, correspond to 2.73% and 7.81% */ |
| 2134 | usePrefetchDecoder = (info.longOffsetShare >= minShare); |
| 2135 | } |
| 2136 | } |
| 2137 | |
| 2138 | dctx->ddictIsCold = 0; |
| 2139 | |
| 2140 | #if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \ |
| 2141 | !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG) |
| 2142 | if (usePrefetchDecoder) { |
| 2143 | #else |
| 2144 | (void)usePrefetchDecoder; |
| 2145 | { |
| 2146 | #endif |
| 2147 | #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT |
| 2148 | return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); |
| 2149 | #endif |
| 2150 | } |
| 2151 | |
| 2152 | #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG |
| 2153 | /* else */ |
| 2154 | if (dctx->litBufferLocation == ZSTD_split) |
| 2155 | return ZSTD_decompressSequencesSplitLitBuffer(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); |
| 2156 | else |
| 2157 | return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); |
| 2158 | #endif |
| 2159 | } |
| 2160 | } |
| 2161 | |
| 2162 | |
| 2163 | void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize) |
| 2164 | { |
| 2165 | if (dst != dctx->previousDstEnd && dstSize > 0) { /* not contiguous */ |
| 2166 | dctx->dictEnd = dctx->previousDstEnd; |
| 2167 | dctx->virtualStart = (const char*)dst - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->prefixStart)); |
| 2168 | dctx->prefixStart = dst; |
| 2169 | dctx->previousDstEnd = dst; |
| 2170 | } |
| 2171 | } |
| 2172 | |
| 2173 | |
| 2174 | size_t ZSTD_decompressBlock_deprecated(ZSTD_DCtx* dctx, |
| 2175 | void* dst, size_t dstCapacity, |
| 2176 | const void* src, size_t srcSize) |
| 2177 | { |
| 2178 | size_t dSize; |
| 2179 | ZSTD_checkContinuity(dctx, dst, dstCapacity); |
| 2180 | dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 0, not_streaming); |
| 2181 | dctx->previousDstEnd = (char*)dst + dSize; |
| 2182 | return dSize; |
| 2183 | } |
| 2184 | |
| 2185 | |
| 2186 | /* NOTE: Must just wrap ZSTD_decompressBlock_deprecated() */ |
| 2187 | size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, |
| 2188 | void* dst, size_t dstCapacity, |
| 2189 | const void* src, size_t srcSize) |
| 2190 | { |
| 2191 | return ZSTD_decompressBlock_deprecated(dctx, dst, dstCapacity, src, srcSize); |
| 2192 | } |