diff options
Diffstat (limited to 'thirdparty/zstd/decompress/zstd_decompress_block.c')
| -rw-r--r-- | thirdparty/zstd/decompress/zstd_decompress_block.c | 1186 |
1 files changed, 913 insertions, 273 deletions
diff --git a/thirdparty/zstd/decompress/zstd_decompress_block.c b/thirdparty/zstd/decompress/zstd_decompress_block.c index ad3b3d8dbd..2e44d30d2f 100644 --- a/thirdparty/zstd/decompress/zstd_decompress_block.c +++ b/thirdparty/zstd/decompress/zstd_decompress_block.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc. + * Copyright (c) Yann Collet, Facebook, Inc. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the @@ -14,7 +14,7 @@ /*-******************************************************* * Dependencies *********************************************************/ -#include <string.h> /* memcpy, memmove, memset */ +#include "../common/zstd_deps.h" /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */ #include "../common/compiler.h" /* prefetch */ #include "../common/cpu.h" /* bmi2 */ #include "../common/mem.h" /* low level memory routines */ @@ -44,7 +44,7 @@ /*_******************************************************* * Memory operations **********************************************************/ -static void ZSTD_copy4(void* dst, const void* src) { memcpy(dst, src, 4); } +static void ZSTD_copy4(void* dst, const void* src) { ZSTD_memcpy(dst, src, 4); } /*-************************************************************* @@ -69,15 +69,56 @@ size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, } } +/* Allocate buffer for literals, either overlapping current dst, or split between dst and litExtraBuffer, or stored entirely within litExtraBuffer */ +static void ZSTD_allocateLiteralsBuffer(ZSTD_DCtx* dctx, void* const dst, const size_t dstCapacity, const size_t litSize, + const streaming_operation streaming, const size_t expectedWriteSize, const unsigned splitImmediately) +{ + if (streaming == not_streaming && dstCapacity > ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH + litSize + WILDCOPY_OVERLENGTH) + { + /* room for litbuffer to fit without read faulting */ + dctx->litBuffer = (BYTE*)dst + ZSTD_BLOCKSIZE_MAX + WILDCOPY_OVERLENGTH; + dctx->litBufferEnd = dctx->litBuffer + litSize; + dctx->litBufferLocation = ZSTD_in_dst; + } + else if (litSize > ZSTD_LITBUFFEREXTRASIZE) + { + /* won't fit in litExtraBuffer, so it will be split between end of dst and extra buffer */ + if (splitImmediately) { + /* won't fit in litExtraBuffer, so it will be split between end of dst and extra buffer */ + dctx->litBuffer = (BYTE*)dst + expectedWriteSize - litSize + ZSTD_LITBUFFEREXTRASIZE - WILDCOPY_OVERLENGTH; + dctx->litBufferEnd = dctx->litBuffer + litSize - ZSTD_LITBUFFEREXTRASIZE; + } + else { + /* initially this will be stored entirely in dst during huffman decoding, it will partially shifted to litExtraBuffer after */ + dctx->litBuffer = (BYTE*)dst + expectedWriteSize - litSize; + dctx->litBufferEnd = (BYTE*)dst + expectedWriteSize; + } + dctx->litBufferLocation = ZSTD_split; + } + else + { + /* fits entirely within litExtraBuffer, so no split is necessary */ + dctx->litBuffer = dctx->litExtraBuffer; + dctx->litBufferEnd = dctx->litBuffer + litSize; + dctx->litBufferLocation = ZSTD_not_in_dst; + } +} /* Hidden declaration for fullbench */ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, - const void* src, size_t srcSize); + const void* src, size_t srcSize, + void* dst, size_t dstCapacity, const streaming_operation streaming); /*! ZSTD_decodeLiteralsBlock() : + * Where it is possible to do so without being stomped by the output during decompression, the literals block will be stored + * 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 + * block will be output. Otherwise it will be stored at the end of the current dst blockspace, with a small portion being + * stored in dctx->litExtraBuffer to help keep it "ahead" of the current output write. + * * @return : nb of bytes read from src (< srcSize ) * note : symbol not declared but exposed for fullbench */ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, - const void* src, size_t srcSize) /* note : srcSize < BLOCKSIZE */ + const void* src, size_t srcSize, /* note : srcSize < BLOCKSIZE */ + void* dst, size_t dstCapacity, const streaming_operation streaming) { DEBUGLOG(5, "ZSTD_decodeLiteralsBlock"); RETURN_ERROR_IF(srcSize < MIN_CBLOCK_SIZE, corruption_detected, ""); @@ -90,7 +131,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, case set_repeat: DEBUGLOG(5, "set_repeat flag : re-using stats from previous compressed literals block"); RETURN_ERROR_IF(dctx->litEntropy==0, dictionary_corrupted, ""); - /* fall-through */ + ZSTD_FALLTHROUGH; case set_compressed: RETURN_ERROR_IF(srcSize < 5, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3"); @@ -99,6 +140,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, U32 const lhlCode = (istart[0] >> 2) & 3; U32 const lhc = MEM_readLE32(istart); size_t hufSuccess; + size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); switch(lhlCode) { case 0: case 1: default: /* note : default is impossible, since lhlCode into [0..3] */ @@ -121,8 +163,11 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, litCSize = (lhc >> 22) + ((size_t)istart[4] << 10); break; } + RETURN_ERROR_IF(litSize > 0 && dst == NULL, dstSize_tooSmall, "NULL not handled"); RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected, ""); RETURN_ERROR_IF(litCSize + lhSize > srcSize, corruption_detected, ""); + RETURN_ERROR_IF(expectedWriteSize < litSize , dstSize_tooSmall, ""); + ZSTD_allocateLiteralsBuffer(dctx, dst, dstCapacity, litSize, streaming, expectedWriteSize, 0); /* prefetch huffman table if cold */ if (dctx->ddictIsCold && (litSize > 768 /* heuristic */)) { @@ -133,11 +178,11 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, if (singleStream) { hufSuccess = HUF_decompress1X_usingDTable_bmi2( dctx->litBuffer, litSize, istart+lhSize, litCSize, - dctx->HUFptr, dctx->bmi2); + dctx->HUFptr, ZSTD_DCtx_get_bmi2(dctx)); } else { hufSuccess = HUF_decompress4X_usingDTable_bmi2( dctx->litBuffer, litSize, istart+lhSize, litCSize, - dctx->HUFptr, dctx->bmi2); + dctx->HUFptr, ZSTD_DCtx_get_bmi2(dctx)); } } else { if (singleStream) { @@ -150,15 +195,22 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, hufSuccess = HUF_decompress1X1_DCtx_wksp_bmi2( dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize, dctx->workspace, - sizeof(dctx->workspace), dctx->bmi2); + sizeof(dctx->workspace), ZSTD_DCtx_get_bmi2(dctx)); #endif } else { hufSuccess = HUF_decompress4X_hufOnly_wksp_bmi2( dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize, dctx->workspace, - sizeof(dctx->workspace), dctx->bmi2); + sizeof(dctx->workspace), ZSTD_DCtx_get_bmi2(dctx)); } } + if (dctx->litBufferLocation == ZSTD_split) + { + ZSTD_memcpy(dctx->litExtraBuffer, dctx->litBufferEnd - ZSTD_LITBUFFEREXTRASIZE, ZSTD_LITBUFFEREXTRASIZE); + ZSTD_memmove(dctx->litBuffer + ZSTD_LITBUFFEREXTRASIZE - WILDCOPY_OVERLENGTH, dctx->litBuffer, litSize - ZSTD_LITBUFFEREXTRASIZE); + dctx->litBuffer += ZSTD_LITBUFFEREXTRASIZE - WILDCOPY_OVERLENGTH; + dctx->litBufferEnd -= WILDCOPY_OVERLENGTH; + } RETURN_ERROR_IF(HUF_isError(hufSuccess), corruption_detected, ""); @@ -166,13 +218,13 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, dctx->litSize = litSize; dctx->litEntropy = 1; if (litEncType==set_compressed) dctx->HUFptr = dctx->entropy.hufTable; - memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH); return litCSize + lhSize; } case set_basic: { size_t litSize, lhSize; U32 const lhlCode = ((istart[0]) >> 2) & 3; + size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); switch(lhlCode) { case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */ @@ -189,23 +241,36 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, break; } + RETURN_ERROR_IF(litSize > 0 && dst == NULL, dstSize_tooSmall, "NULL not handled"); + RETURN_ERROR_IF(expectedWriteSize < litSize, dstSize_tooSmall, ""); + ZSTD_allocateLiteralsBuffer(dctx, dst, dstCapacity, litSize, streaming, expectedWriteSize, 1); if (lhSize+litSize+WILDCOPY_OVERLENGTH > srcSize) { /* risk reading beyond src buffer with wildcopy */ RETURN_ERROR_IF(litSize+lhSize > srcSize, corruption_detected, ""); - memcpy(dctx->litBuffer, istart+lhSize, litSize); + if (dctx->litBufferLocation == ZSTD_split) + { + ZSTD_memcpy(dctx->litBuffer, istart + lhSize, litSize - ZSTD_LITBUFFEREXTRASIZE); + ZSTD_memcpy(dctx->litExtraBuffer, istart + lhSize + litSize - ZSTD_LITBUFFEREXTRASIZE, ZSTD_LITBUFFEREXTRASIZE); + } + else + { + ZSTD_memcpy(dctx->litBuffer, istart + lhSize, litSize); + } dctx->litPtr = dctx->litBuffer; dctx->litSize = litSize; - memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH); return lhSize+litSize; } /* direct reference into compressed stream */ dctx->litPtr = istart+lhSize; dctx->litSize = litSize; + dctx->litBufferEnd = dctx->litPtr + litSize; + dctx->litBufferLocation = ZSTD_not_in_dst; return lhSize+litSize; } case set_rle: { U32 const lhlCode = ((istart[0]) >> 2) & 3; size_t litSize, lhSize; + size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); switch(lhlCode) { case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */ @@ -222,8 +287,19 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, RETURN_ERROR_IF(srcSize<4, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4"); break; } + RETURN_ERROR_IF(litSize > 0 && dst == NULL, dstSize_tooSmall, "NULL not handled"); RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected, ""); - memset(dctx->litBuffer, istart[lhSize], litSize + WILDCOPY_OVERLENGTH); + RETURN_ERROR_IF(expectedWriteSize < litSize, dstSize_tooSmall, ""); + ZSTD_allocateLiteralsBuffer(dctx, dst, dstCapacity, litSize, streaming, expectedWriteSize, 1); + if (dctx->litBufferLocation == ZSTD_split) + { + ZSTD_memset(dctx->litBuffer, istart[lhSize], litSize - ZSTD_LITBUFFEREXTRASIZE); + ZSTD_memset(dctx->litExtraBuffer, istart[lhSize], ZSTD_LITBUFFEREXTRASIZE); + } + else + { + ZSTD_memset(dctx->litBuffer, istart[lhSize], litSize); + } dctx->litPtr = dctx->litBuffer; dctx->litSize = litSize; return lhSize+1; @@ -236,7 +312,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, /* Default FSE distribution tables. * These are pre-calculated FSE decoding tables using default distributions as defined in specification : - * https://github.com/facebook/zstd/blob/master/doc/zstd_compression_format.md#default-distributions + * https://github.com/facebook/zstd/blob/release/doc/zstd_compression_format.md#default-distributions * They were generated programmatically with following method : * - start from default distributions, present in /lib/common/zstd_internal.h * - generate tables normally, using ZSTD_buildFSETable() @@ -343,7 +419,7 @@ static const ZSTD_seqSymbol ML_defaultDTable[(1<<ML_DEFAULTNORMLOG)+1] = { }; /* ML_defaultDTable */ -static void ZSTD_buildSeqTable_rle(ZSTD_seqSymbol* dt, U32 baseValue, U32 nbAddBits) +static void ZSTD_buildSeqTable_rle(ZSTD_seqSymbol* dt, U32 baseValue, U8 nbAddBits) { void* ptr = dt; ZSTD_seqSymbol_header* const DTableH = (ZSTD_seqSymbol_header*)ptr; @@ -355,7 +431,7 @@ static void ZSTD_buildSeqTable_rle(ZSTD_seqSymbol* dt, U32 baseValue, U32 nbAddB cell->nbBits = 0; cell->nextState = 0; assert(nbAddBits < 255); - cell->nbAdditionalBits = (BYTE)nbAddBits; + cell->nbAdditionalBits = nbAddBits; cell->baseValue = baseValue; } @@ -364,23 +440,26 @@ static void ZSTD_buildSeqTable_rle(ZSTD_seqSymbol* dt, U32 baseValue, U32 nbAddB * generate FSE decoding table for one symbol (ll, ml or off) * cannot fail if input is valid => * all inputs are presumed validated at this stage */ -void -ZSTD_buildFSETable(ZSTD_seqSymbol* dt, +FORCE_INLINE_TEMPLATE +void ZSTD_buildFSETable_body(ZSTD_seqSymbol* dt, const short* normalizedCounter, unsigned maxSymbolValue, - const U32* baseValue, const U32* nbAdditionalBits, - unsigned tableLog) + const U32* baseValue, const U8* nbAdditionalBits, + unsigned tableLog, void* wksp, size_t wkspSize) { ZSTD_seqSymbol* const tableDecode = dt+1; - U16 symbolNext[MaxSeq+1]; - U32 const maxSV1 = maxSymbolValue + 1; U32 const tableSize = 1 << tableLog; - U32 highThreshold = tableSize-1; + + U16* symbolNext = (U16*)wksp; + BYTE* spread = (BYTE*)(symbolNext + MaxSeq + 1); + U32 highThreshold = tableSize - 1; + /* Sanity Checks */ assert(maxSymbolValue <= MaxSeq); assert(tableLog <= MaxFSELog); - + assert(wkspSize >= ZSTD_BUILD_FSE_TABLE_WKSP_SIZE); + (void)wkspSize; /* Init, lay down lowprob symbols */ { ZSTD_seqSymbol_header DTableH; DTableH.tableLog = tableLog; @@ -396,16 +475,69 @@ ZSTD_buildFSETable(ZSTD_seqSymbol* dt, assert(normalizedCounter[s]>=0); symbolNext[s] = (U16)normalizedCounter[s]; } } } - memcpy(dt, &DTableH, sizeof(DTableH)); + ZSTD_memcpy(dt, &DTableH, sizeof(DTableH)); } /* Spread symbols */ - { U32 const tableMask = tableSize-1; + assert(tableSize <= 512); + /* Specialized symbol spreading for the case when there are + * no low probability (-1 count) symbols. When compressing + * small blocks we avoid low probability symbols to hit this + * case, since header decoding speed matters more. + */ + if (highThreshold == tableSize - 1) { + size_t const tableMask = tableSize-1; + size_t const step = FSE_TABLESTEP(tableSize); + /* First lay down the symbols in order. + * We use a uint64_t to lay down 8 bytes at a time. This reduces branch + * misses since small blocks generally have small table logs, so nearly + * all symbols have counts <= 8. We ensure we have 8 bytes at the end of + * our buffer to handle the over-write. + */ + { + U64 const add = 0x0101010101010101ull; + size_t pos = 0; + U64 sv = 0; + U32 s; + for (s=0; s<maxSV1; ++s, sv += add) { + int i; + int const n = normalizedCounter[s]; + MEM_write64(spread + pos, sv); + for (i = 8; i < n; i += 8) { + MEM_write64(spread + pos + i, sv); + } + pos += n; + } + } + /* Now we spread those positions across the table. + * The benefit of doing it in two stages is that we avoid the the + * variable size inner loop, which caused lots of branch misses. + * Now we can run through all the positions without any branch misses. + * We unroll the loop twice, since that is what emperically worked best. + */ + { + size_t position = 0; + size_t s; + size_t const unroll = 2; + assert(tableSize % unroll == 0); /* FSE_MIN_TABLELOG is 5 */ + for (s = 0; s < (size_t)tableSize; s += unroll) { + size_t u; + for (u = 0; u < unroll; ++u) { + size_t const uPosition = (position + (u * step)) & tableMask; + tableDecode[uPosition].baseValue = spread[s + u]; + } + position = (position + (unroll * step)) & tableMask; + } + assert(position == 0); + } + } else { + U32 const tableMask = tableSize-1; U32 const step = FSE_TABLESTEP(tableSize); U32 s, position = 0; for (s=0; s<maxSV1; s++) { int i; - for (i=0; i<normalizedCounter[s]; i++) { + int const n = normalizedCounter[s]; + for (i=0; i<n; i++) { tableDecode[position].baseValue = s; position = (position + step) & tableMask; while (position > highThreshold) position = (position + step) & tableMask; /* lowprob area */ @@ -414,16 +546,56 @@ ZSTD_buildFSETable(ZSTD_seqSymbol* dt, } /* Build Decoding table */ - { U32 u; + { + U32 u; for (u=0; u<tableSize; u++) { U32 const symbol = tableDecode[u].baseValue; U32 const nextState = symbolNext[symbol]++; tableDecode[u].nbBits = (BYTE) (tableLog - BIT_highbit32(nextState) ); tableDecode[u].nextState = (U16) ( (nextState << tableDecode[u].nbBits) - tableSize); assert(nbAdditionalBits[symbol] < 255); - tableDecode[u].nbAdditionalBits = (BYTE)nbAdditionalBits[symbol]; + tableDecode[u].nbAdditionalBits = nbAdditionalBits[symbol]; tableDecode[u].baseValue = baseValue[symbol]; - } } + } + } +} + +/* Avoids the FORCE_INLINE of the _body() function. */ +static void ZSTD_buildFSETable_body_default(ZSTD_seqSymbol* dt, + const short* normalizedCounter, unsigned maxSymbolValue, + const U32* baseValue, const U8* nbAdditionalBits, + unsigned tableLog, void* wksp, size_t wkspSize) +{ + ZSTD_buildFSETable_body(dt, normalizedCounter, maxSymbolValue, + baseValue, nbAdditionalBits, tableLog, wksp, wkspSize); +} + +#if DYNAMIC_BMI2 +BMI2_TARGET_ATTRIBUTE static void ZSTD_buildFSETable_body_bmi2(ZSTD_seqSymbol* dt, + const short* normalizedCounter, unsigned maxSymbolValue, + const U32* baseValue, const U8* nbAdditionalBits, + unsigned tableLog, void* wksp, size_t wkspSize) +{ + ZSTD_buildFSETable_body(dt, normalizedCounter, maxSymbolValue, + baseValue, nbAdditionalBits, tableLog, wksp, wkspSize); +} +#endif + +void ZSTD_buildFSETable(ZSTD_seqSymbol* dt, + const short* normalizedCounter, unsigned maxSymbolValue, + const U32* baseValue, const U8* nbAdditionalBits, + unsigned tableLog, void* wksp, size_t wkspSize, int bmi2) +{ +#if DYNAMIC_BMI2 + if (bmi2) { + ZSTD_buildFSETable_body_bmi2(dt, normalizedCounter, maxSymbolValue, + baseValue, nbAdditionalBits, tableLog, wksp, wkspSize); + return; + } +#endif + (void)bmi2; + ZSTD_buildFSETable_body_default(dt, normalizedCounter, maxSymbolValue, + baseValue, nbAdditionalBits, tableLog, wksp, wkspSize); } @@ -433,9 +605,10 @@ ZSTD_buildFSETable(ZSTD_seqSymbol* dt, static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymbol** DTablePtr, symbolEncodingType_e type, unsigned max, U32 maxLog, const void* src, size_t srcSize, - const U32* baseValue, const U32* nbAdditionalBits, + const U32* baseValue, const U8* nbAdditionalBits, const ZSTD_seqSymbol* defaultTable, U32 flagRepeatTable, - int ddictIsCold, int nbSeq) + int ddictIsCold, int nbSeq, U32* wksp, size_t wkspSize, + int bmi2) { switch(type) { @@ -444,7 +617,7 @@ static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymb RETURN_ERROR_IF((*(const BYTE*)src) > max, corruption_detected, ""); { U32 const symbol = *(const BYTE*)src; U32 const baseline = baseValue[symbol]; - U32 const nbBits = nbAdditionalBits[symbol]; + U8 const nbBits = nbAdditionalBits[symbol]; ZSTD_buildSeqTable_rle(DTableSpace, baseline, nbBits); } *DTablePtr = DTableSpace; @@ -467,7 +640,7 @@ static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymb size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize); RETURN_ERROR_IF(FSE_isError(headerSize), corruption_detected, ""); RETURN_ERROR_IF(tableLog > maxLog, corruption_detected, ""); - ZSTD_buildFSETable(DTableSpace, norm, max, baseValue, nbAdditionalBits, tableLog); + ZSTD_buildFSETable(DTableSpace, norm, max, baseValue, nbAdditionalBits, tableLog, wksp, wkspSize, bmi2); *DTablePtr = DTableSpace; return headerSize; } @@ -480,7 +653,7 @@ static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymb size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr, const void* src, size_t srcSize) { - const BYTE* const istart = (const BYTE* const)src; + const BYTE* const istart = (const BYTE*)src; const BYTE* const iend = istart + srcSize; const BYTE* ip = istart; int nbSeq; @@ -499,7 +672,8 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr, if (nbSeq > 0x7F) { if (nbSeq == 0xFF) { RETURN_ERROR_IF(ip+2 > iend, srcSize_wrong, ""); - nbSeq = MEM_readLE16(ip) + LONGNBSEQ, ip+=2; + nbSeq = MEM_readLE16(ip) + LONGNBSEQ; + ip+=2; } else { RETURN_ERROR_IF(ip >= iend, srcSize_wrong, ""); nbSeq = ((nbSeq-0x80)<<8) + *ip++; @@ -520,7 +694,9 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr, ip, iend-ip, LL_base, LL_bits, LL_defaultDTable, dctx->fseEntropy, - dctx->ddictIsCold, nbSeq); + dctx->ddictIsCold, nbSeq, + dctx->workspace, sizeof(dctx->workspace), + ZSTD_DCtx_get_bmi2(dctx)); RETURN_ERROR_IF(ZSTD_isError(llhSize), corruption_detected, "ZSTD_buildSeqTable failed"); ip += llhSize; } @@ -530,7 +706,9 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr, ip, iend-ip, OF_base, OF_bits, OF_defaultDTable, dctx->fseEntropy, - dctx->ddictIsCold, nbSeq); + dctx->ddictIsCold, nbSeq, + dctx->workspace, sizeof(dctx->workspace), + ZSTD_DCtx_get_bmi2(dctx)); RETURN_ERROR_IF(ZSTD_isError(ofhSize), corruption_detected, "ZSTD_buildSeqTable failed"); ip += ofhSize; } @@ -540,7 +718,9 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr, ip, iend-ip, ML_base, ML_bits, ML_defaultDTable, dctx->fseEntropy, - dctx->ddictIsCold, nbSeq); + dctx->ddictIsCold, nbSeq, + dctx->workspace, sizeof(dctx->workspace), + ZSTD_DCtx_get_bmi2(dctx)); RETURN_ERROR_IF(ZSTD_isError(mlhSize), corruption_detected, "ZSTD_buildSeqTable failed"); ip += mlhSize; } @@ -554,7 +734,6 @@ typedef struct { size_t litLength; size_t matchLength; size_t offset; - const BYTE* match; } seq_t; typedef struct { @@ -568,9 +747,6 @@ typedef struct { ZSTD_fseState stateOffb; ZSTD_fseState stateML; size_t prevOffset[ZSTD_REP_NUM]; - const BYTE* prefixStart; - const BYTE* dictEnd; - size_t pos; } seqState_t; /*! ZSTD_overlapCopy8() : @@ -613,7 +789,7 @@ HINT_INLINE void ZSTD_overlapCopy8(BYTE** op, BYTE const** ip, size_t offset) { * - ZSTD_overlap_src_before_dst: The src and dst may overlap and may be any distance apart. * The src buffer must be before the dst buffer. */ -static void ZSTD_safecopy(BYTE* op, BYTE* const oend_w, BYTE const* ip, ptrdiff_t length, ZSTD_overlap_e ovtype) { +static void ZSTD_safecopy(BYTE* op, const BYTE* const oend_w, BYTE const* ip, ptrdiff_t length, ZSTD_overlap_e ovtype) { ptrdiff_t const diff = op - ip; BYTE* const oend = op + length; @@ -629,6 +805,7 @@ static void ZSTD_safecopy(BYTE* op, BYTE* const oend_w, BYTE const* ip, ptrdiff_ /* Copy 8 bytes and ensure the offset >= 8 when there can be overlap. */ assert(length >= 8); ZSTD_overlapCopy8(&op, &ip, diff); + length -= 8; assert(op - ip >= 8); assert(op <= oend); } @@ -643,8 +820,31 @@ static void ZSTD_safecopy(BYTE* op, BYTE* const oend_w, BYTE const* ip, ptrdiff_ assert(oend > oend_w); ZSTD_wildcopy(op, ip, oend_w - op, ovtype); ip += oend_w - op; - op = oend_w; + op += oend_w - op; + } + /* Handle the leftovers. */ + while (op < oend) *op++ = *ip++; +} + +/* ZSTD_safecopyDstBeforeSrc(): + * This version allows overlap with dst before src, or handles the non-overlap case with dst after src + * Kept separate from more common ZSTD_safecopy case to avoid performance impact to the safecopy common case */ +static void ZSTD_safecopyDstBeforeSrc(BYTE* op, BYTE const* ip, ptrdiff_t length) { + ptrdiff_t const diff = op - ip; + BYTE* const oend = op + length; + + if (length < 8 || diff > -8) { + /* Handle short lengths, close overlaps, and dst not before src. */ + while (op < oend) *op++ = *ip++; + return; + } + + if (op <= oend - WILDCOPY_OVERLENGTH && diff < -WILDCOPY_VECLEN) { + ZSTD_wildcopy(op, ip, oend - WILDCOPY_OVERLENGTH - op, ZSTD_no_overlap); + ip += oend - WILDCOPY_OVERLENGTH - op; + op += oend - WILDCOPY_OVERLENGTH - op; } + /* Handle the leftovers. */ while (op < oend) *op++ = *ip++; } @@ -659,9 +859,9 @@ static void ZSTD_safecopy(BYTE* op, BYTE* const oend_w, BYTE const* ip, ptrdiff_ */ FORCE_NOINLINE size_t ZSTD_execSequenceEnd(BYTE* op, - BYTE* const oend, seq_t sequence, - const BYTE** litPtr, const BYTE* const litLimit, - const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) + BYTE* const oend, seq_t sequence, + const BYTE** litPtr, const BYTE* const litLimit, + const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) { BYTE* const oLitEnd = op + sequence.litLength; size_t const sequenceLength = sequence.litLength + sequence.matchLength; @@ -684,27 +884,76 @@ size_t ZSTD_execSequenceEnd(BYTE* op, if (sequence.offset > (size_t)(oLitEnd - prefixStart)) { /* offset beyond prefix */ RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - virtualStart), corruption_detected, ""); - match = dictEnd - (prefixStart-match); + match = dictEnd - (prefixStart - match); if (match + sequence.matchLength <= dictEnd) { - memmove(oLitEnd, match, sequence.matchLength); + ZSTD_memmove(oLitEnd, match, sequence.matchLength); return sequenceLength; } /* span extDict & currentPrefixSegment */ { size_t const length1 = dictEnd - match; - memmove(oLitEnd, match, length1); - op = oLitEnd + length1; - sequence.matchLength -= length1; - match = prefixStart; - } } + ZSTD_memmove(oLitEnd, match, length1); + op = oLitEnd + length1; + sequence.matchLength -= length1; + match = prefixStart; + } + } + ZSTD_safecopy(op, oend_w, match, sequence.matchLength, ZSTD_overlap_src_before_dst); + return sequenceLength; +} + +/* ZSTD_execSequenceEndSplitLitBuffer(): + * 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. + */ +FORCE_NOINLINE +size_t ZSTD_execSequenceEndSplitLitBuffer(BYTE* op, + BYTE* const oend, const BYTE* const oend_w, seq_t sequence, + const BYTE** litPtr, const BYTE* const litLimit, + const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) +{ + BYTE* const oLitEnd = op + sequence.litLength; + size_t const sequenceLength = sequence.litLength + sequence.matchLength; + const BYTE* const iLitEnd = *litPtr + sequence.litLength; + const BYTE* match = oLitEnd - sequence.offset; + + + /* bounds checks : careful of address space overflow in 32-bit mode */ + RETURN_ERROR_IF(sequenceLength > (size_t)(oend - op), dstSize_tooSmall, "last match must fit within dstBuffer"); + RETURN_ERROR_IF(sequence.litLength > (size_t)(litLimit - *litPtr), corruption_detected, "try to read beyond literal buffer"); + assert(op < op + sequenceLength); + assert(oLitEnd < op + sequenceLength); + + /* copy literals */ + RETURN_ERROR_IF(op > *litPtr && op < *litPtr + sequence.litLength, dstSize_tooSmall, "output should not catch up to and overwrite literal buffer"); + ZSTD_safecopyDstBeforeSrc(op, *litPtr, sequence.litLength); + op = oLitEnd; + *litPtr = iLitEnd; + + /* copy Match */ + if (sequence.offset > (size_t)(oLitEnd - prefixStart)) { + /* offset beyond prefix */ + RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - virtualStart), corruption_detected, ""); + match = dictEnd - (prefixStart - match); + if (match + sequence.matchLength <= dictEnd) { + ZSTD_memmove(oLitEnd, match, sequence.matchLength); + return sequenceLength; + } + /* span extDict & currentPrefixSegment */ + { size_t const length1 = dictEnd - match; + ZSTD_memmove(oLitEnd, match, length1); + op = oLitEnd + length1; + sequence.matchLength -= length1; + match = prefixStart; + } + } ZSTD_safecopy(op, oend_w, match, sequence.matchLength, ZSTD_overlap_src_before_dst); return sequenceLength; } HINT_INLINE size_t ZSTD_execSequence(BYTE* op, - BYTE* const oend, seq_t sequence, - const BYTE** litPtr, const BYTE* const litLimit, - const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) + BYTE* const oend, seq_t sequence, + const BYTE** litPtr, const BYTE* const litLimit, + const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) { BYTE* const oLitEnd = op + sequence.litLength; size_t const sequenceLength = sequence.litLength + sequence.matchLength; @@ -721,10 +970,102 @@ size_t ZSTD_execSequence(BYTE* op, * - 32-bit mode and the match length overflows */ if (UNLIKELY( + iLitEnd > litLimit || + oMatchEnd > oend_w || + (MEM_32bits() && (size_t)(oend - op) < sequenceLength + WILDCOPY_OVERLENGTH))) + return ZSTD_execSequenceEnd(op, oend, sequence, litPtr, litLimit, prefixStart, virtualStart, dictEnd); + + /* Assumptions (everything else goes into ZSTD_execSequenceEnd()) */ + assert(op <= oLitEnd /* No overflow */); + assert(oLitEnd < oMatchEnd /* Non-zero match & no overflow */); + assert(oMatchEnd <= oend /* No underflow */); + assert(iLitEnd <= litLimit /* Literal length is in bounds */); + assert(oLitEnd <= oend_w /* Can wildcopy literals */); + assert(oMatchEnd <= oend_w /* Can wildcopy matches */); + + /* Copy Literals: + * Split out litLength <= 16 since it is nearly always true. +1.6% on gcc-9. + * We likely don't need the full 32-byte wildcopy. + */ + assert(WILDCOPY_OVERLENGTH >= 16); + ZSTD_copy16(op, (*litPtr)); + if (UNLIKELY(sequence.litLength > 16)) { + ZSTD_wildcopy(op + 16, (*litPtr) + 16, sequence.litLength - 16, ZSTD_no_overlap); + } + op = oLitEnd; + *litPtr = iLitEnd; /* update for next sequence */ + + /* Copy Match */ + if (sequence.offset > (size_t)(oLitEnd - prefixStart)) { + /* offset beyond prefix -> go into extDict */ + RETURN_ERROR_IF(UNLIKELY(sequence.offset > (size_t)(oLitEnd - virtualStart)), corruption_detected, ""); + match = dictEnd + (match - prefixStart); + if (match + sequence.matchLength <= dictEnd) { + ZSTD_memmove(oLitEnd, match, sequence.matchLength); + return sequenceLength; + } + /* span extDict & currentPrefixSegment */ + { size_t const length1 = dictEnd - match; + ZSTD_memmove(oLitEnd, match, length1); + op = oLitEnd + length1; + sequence.matchLength -= length1; + match = prefixStart; + } + } + /* Match within prefix of 1 or more bytes */ + assert(op <= oMatchEnd); + assert(oMatchEnd <= oend_w); + assert(match >= prefixStart); + assert(sequence.matchLength >= 1); + + /* Nearly all offsets are >= WILDCOPY_VECLEN bytes, which means we can use wildcopy + * without overlap checking. + */ + if (LIKELY(sequence.offset >= WILDCOPY_VECLEN)) { + /* We bet on a full wildcopy for matches, since we expect matches to be + * longer than literals (in general). In silesia, ~10% of matches are longer + * than 16 bytes. + */ + ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength, ZSTD_no_overlap); + return sequenceLength; + } + assert(sequence.offset < WILDCOPY_VECLEN); + + /* Copy 8 bytes and spread the offset to be >= 8. */ + ZSTD_overlapCopy8(&op, &match, sequence.offset); + + /* If the match length is > 8 bytes, then continue with the wildcopy. */ + if (sequence.matchLength > 8) { + assert(op < oMatchEnd); + ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength - 8, ZSTD_overlap_src_before_dst); + } + return sequenceLength; +} + +HINT_INLINE +size_t ZSTD_execSequenceSplitLitBuffer(BYTE* op, + BYTE* const oend, const BYTE* const oend_w, seq_t sequence, + const BYTE** litPtr, const BYTE* const litLimit, + const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd) +{ + BYTE* const oLitEnd = op + sequence.litLength; + size_t const sequenceLength = sequence.litLength + sequence.matchLength; + BYTE* const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */ + const BYTE* const iLitEnd = *litPtr + sequence.litLength; + const BYTE* match = oLitEnd - sequence.offset; + + assert(op != NULL /* Precondition */); + assert(oend_w < oend /* No underflow */); + /* Handle edge cases in a slow path: + * - Read beyond end of literals + * - Match end is within WILDCOPY_OVERLIMIT of oend + * - 32-bit mode and the match length overflows + */ + if (UNLIKELY( iLitEnd > litLimit || oMatchEnd > oend_w || (MEM_32bits() && (size_t)(oend - op) < sequenceLength + WILDCOPY_OVERLENGTH))) - return ZSTD_execSequenceEnd(op, oend, sequence, litPtr, litLimit, prefixStart, virtualStart, dictEnd); + return ZSTD_execSequenceEndSplitLitBuffer(op, oend, oend_w, sequence, litPtr, litLimit, prefixStart, virtualStart, dictEnd); /* Assumptions (everything else goes into ZSTD_execSequenceEnd()) */ assert(op <= oLitEnd /* No overflow */); @@ -752,12 +1093,12 @@ size_t ZSTD_execSequence(BYTE* op, RETURN_ERROR_IF(UNLIKELY(sequence.offset > (size_t)(oLitEnd - virtualStart)), corruption_detected, ""); match = dictEnd + (match - prefixStart); if (match + sequence.matchLength <= dictEnd) { - memmove(oLitEnd, match, sequence.matchLength); + ZSTD_memmove(oLitEnd, match, sequence.matchLength); return sequenceLength; } /* span extDict & currentPrefixSegment */ { size_t const length1 = dictEnd - match; - memmove(oLitEnd, match, length1); + ZSTD_memmove(oLitEnd, match, length1); op = oLitEnd + length1; sequence.matchLength -= length1; match = prefixStart; @@ -792,6 +1133,7 @@ size_t ZSTD_execSequence(BYTE* op, return sequenceLength; } + static void ZSTD_initFseState(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, const ZSTD_seqSymbol* dt) { @@ -805,20 +1147,10 @@ ZSTD_initFseState(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, const ZSTD_seqS } FORCE_INLINE_TEMPLATE void -ZSTD_updateFseState(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD) +ZSTD_updateFseStateWithDInfo(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, U16 nextState, U32 nbBits) { - ZSTD_seqSymbol const DInfo = DStatePtr->table[DStatePtr->state]; - U32 const nbBits = DInfo.nbBits; size_t const lowBits = BIT_readBits(bitD, nbBits); - DStatePtr->state = DInfo.nextState + lowBits; -} - -FORCE_INLINE_TEMPLATE void -ZSTD_updateFseStateWithDInfo(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, ZSTD_seqSymbol const DInfo) -{ - U32 const nbBits = DInfo.nbBits; - size_t const lowBits = BIT_readBits(bitD, nbBits); - DStatePtr->state = DInfo.nextState + lowBits; + DStatePtr->state = nextState + lowBits; } /* We need to add at most (ZSTD_WINDOWLOG_MAX_32 - 1) bits to read the maximum @@ -832,123 +1164,112 @@ ZSTD_updateFseStateWithDInfo(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, ZSTD : 0) typedef enum { ZSTD_lo_isRegularOffset, ZSTD_lo_isLongOffset=1 } ZSTD_longOffset_e; -typedef enum { ZSTD_p_noPrefetch=0, ZSTD_p_prefetch=1 } ZSTD_prefetch_e; FORCE_INLINE_TEMPLATE seq_t -ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets, const ZSTD_prefetch_e prefetch) +ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) { seq_t seq; - ZSTD_seqSymbol const llDInfo = seqState->stateLL.table[seqState->stateLL.state]; - ZSTD_seqSymbol const mlDInfo = seqState->stateML.table[seqState->stateML.state]; - ZSTD_seqSymbol const ofDInfo = seqState->stateOffb.table[seqState->stateOffb.state]; - U32 const llBase = llDInfo.baseValue; - U32 const mlBase = mlDInfo.baseValue; - U32 const ofBase = ofDInfo.baseValue; - BYTE const llBits = llDInfo.nbAdditionalBits; - BYTE const mlBits = mlDInfo.nbAdditionalBits; - BYTE const ofBits = ofDInfo.nbAdditionalBits; - BYTE const totalBits = llBits+mlBits+ofBits; - - /* sequence */ - { size_t offset; - if (ofBits > 1) { - ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1); - ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5); - assert(ofBits <= MaxOff); - if (MEM_32bits() && longOffsets && (ofBits >= STREAM_ACCUMULATOR_MIN_32)) { - U32 const extraBits = ofBits - MIN(ofBits, 32 - seqState->DStream.bitsConsumed); - offset = ofBase + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits); - BIT_reloadDStream(&seqState->DStream); - if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits); - assert(extraBits <= LONG_OFFSETS_MAX_EXTRA_BITS_32); /* to avoid another reload */ - } else { - offset = ofBase + BIT_readBitsFast(&seqState->DStream, ofBits/*>0*/); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */ - if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); - } - seqState->prevOffset[2] = seqState->prevOffset[1]; - seqState->prevOffset[1] = seqState->prevOffset[0]; - seqState->prevOffset[0] = offset; - } else { - U32 const ll0 = (llBase == 0); - if (LIKELY((ofBits == 0))) { - if (LIKELY(!ll0)) - offset = seqState->prevOffset[0]; - else { - offset = seqState->prevOffset[1]; - seqState->prevOffset[1] = seqState->prevOffset[0]; - seqState->prevOffset[0] = offset; + const ZSTD_seqSymbol* const llDInfo = seqState->stateLL.table + seqState->stateLL.state; + const ZSTD_seqSymbol* const mlDInfo = seqState->stateML.table + seqState->stateML.state; + const ZSTD_seqSymbol* const ofDInfo = seqState->stateOffb.table + seqState->stateOffb.state; + seq.matchLength = mlDInfo->baseValue; + seq.litLength = llDInfo->baseValue; + { U32 const ofBase = ofDInfo->baseValue; + BYTE const llBits = llDInfo->nbAdditionalBits; + BYTE const mlBits = mlDInfo->nbAdditionalBits; + BYTE const ofBits = ofDInfo->nbAdditionalBits; + BYTE const totalBits = llBits+mlBits+ofBits; + + U16 const llNext = llDInfo->nextState; + U16 const mlNext = mlDInfo->nextState; + U16 const ofNext = ofDInfo->nextState; + U32 const llnbBits = llDInfo->nbBits; + U32 const mlnbBits = mlDInfo->nbBits; + U32 const ofnbBits = ofDInfo->nbBits; + /* + * As gcc has better branch and block analyzers, sometimes it is only + * valuable to mark likelyness for clang, it gives around 3-4% of + * performance. + */ + + /* sequence */ + { size_t offset; + #if defined(__clang__) + if (LIKELY(ofBits > 1)) { + #else + if (ofBits > 1) { + #endif + ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1); + ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5); + assert(ofBits <= MaxOff); + if (MEM_32bits() && longOffsets && (ofBits >= STREAM_ACCUMULATOR_MIN_32)) { + U32 const extraBits = ofBits - MIN(ofBits, 32 - seqState->DStream.bitsConsumed); + offset = ofBase + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits); + BIT_reloadDStream(&seqState->DStream); + if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits); + assert(extraBits <= LONG_OFFSETS_MAX_EXTRA_BITS_32); /* to avoid another reload */ + } else { + offset = ofBase + BIT_readBitsFast(&seqState->DStream, ofBits/*>0*/); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */ + if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); } + seqState->prevOffset[2] = seqState->prevOffset[1]; + seqState->prevOffset[1] = seqState->prevOffset[0]; + seqState->prevOffset[0] = offset; } else { - offset = ofBase + ll0 + BIT_readBitsFast(&seqState->DStream, 1); - { size_t temp = (offset==3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset]; - temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */ - if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1]; - seqState->prevOffset[1] = seqState->prevOffset[0]; - seqState->prevOffset[0] = offset = temp; - } } } - seq.offset = offset; - } - - seq.matchLength = mlBase; - if (mlBits > 0) - seq.matchLength += BIT_readBitsFast(&seqState->DStream, mlBits/*>0*/); - - if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32)) - BIT_reloadDStream(&seqState->DStream); - if (MEM_64bits() && UNLIKELY(totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog))) - BIT_reloadDStream(&seqState->DStream); - /* Ensure there are enough bits to read the rest of data in 64-bit mode. */ - ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64); - - seq.litLength = llBase; - if (llBits > 0) - seq.litLength += BIT_readBitsFast(&seqState->DStream, llBits/*>0*/); - - if (MEM_32bits()) - BIT_reloadDStream(&seqState->DStream); - - DEBUGLOG(6, "seq: litL=%u, matchL=%u, offset=%u", - (U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset); - - if (prefetch == ZSTD_p_prefetch) { - size_t const pos = seqState->pos + seq.litLength; - const BYTE* const matchBase = (seq.offset > pos) ? seqState->dictEnd : seqState->prefixStart; - seq.match = matchBase + pos - seq.offset; /* note : this operation can overflow when seq.offset is really too large, which can only happen when input is corrupted. - * No consequence though : no memory access will occur, offset is only used for prefetching */ - seqState->pos = pos + seq.matchLength; - } - - /* ANS state update - * gcc-9.0.0 does 2.5% worse with ZSTD_updateFseStateWithDInfo(). - * clang-9.2.0 does 7% worse with ZSTD_updateFseState(). - * Naturally it seems like ZSTD_updateFseStateWithDInfo() should be the - * better option, so it is the default for other compilers. But, if you - * measure that it is worse, please put up a pull request. - */ - { -#if defined(__GNUC__) && !defined(__clang__) - const int kUseUpdateFseState = 1; -#else - const int kUseUpdateFseState = 0; -#endif - if (kUseUpdateFseState) { - ZSTD_updateFseState(&seqState->stateLL, &seqState->DStream); /* <= 9 bits */ - ZSTD_updateFseState(&seqState->stateML, &seqState->DStream); /* <= 9 bits */ - if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */ - ZSTD_updateFseState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */ - } else { - ZSTD_updateFseStateWithDInfo(&seqState->stateLL, &seqState->DStream, llDInfo); /* <= 9 bits */ - ZSTD_updateFseStateWithDInfo(&seqState->stateML, &seqState->DStream, mlDInfo); /* <= 9 bits */ - if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */ - ZSTD_updateFseStateWithDInfo(&seqState->stateOffb, &seqState->DStream, ofDInfo); /* <= 8 bits */ + U32 const ll0 = (llDInfo->baseValue == 0); + if (LIKELY((ofBits == 0))) { + offset = seqState->prevOffset[ll0]; + seqState->prevOffset[1] = seqState->prevOffset[!ll0]; + seqState->prevOffset[0] = offset; + } else { + offset = ofBase + ll0 + BIT_readBitsFast(&seqState->DStream, 1); + { size_t temp = (offset==3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset]; + temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */ + if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1]; + seqState->prevOffset[1] = seqState->prevOffset[0]; + seqState->prevOffset[0] = offset = temp; + } } } + seq.offset = offset; } + + #if defined(__clang__) + if (UNLIKELY(mlBits > 0)) + #else + if (mlBits > 0) + #endif + seq.matchLength += BIT_readBitsFast(&seqState->DStream, mlBits/*>0*/); + + if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32)) + BIT_reloadDStream(&seqState->DStream); + if (MEM_64bits() && UNLIKELY(totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog))) + BIT_reloadDStream(&seqState->DStream); + /* Ensure there are enough bits to read the rest of data in 64-bit mode. */ + ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64); + + #if defined(__clang__) + if (UNLIKELY(llBits > 0)) + #else + if (llBits > 0) + #endif + seq.litLength += BIT_readBitsFast(&seqState->DStream, llBits/*>0*/); + + if (MEM_32bits()) + BIT_reloadDStream(&seqState->DStream); + + DEBUGLOG(6, "seq: litL=%u, matchL=%u, offset=%u", + (U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset); + + ZSTD_updateFseStateWithDInfo(&seqState->stateLL, &seqState->DStream, llNext, llnbBits); /* <= 9 bits */ + ZSTD_updateFseStateWithDInfo(&seqState->stateML, &seqState->DStream, mlNext, mlnbBits); /* <= 9 bits */ + if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */ + ZSTD_updateFseStateWithDInfo(&seqState->stateOffb, &seqState->DStream, ofNext, ofnbBits); /* <= 8 bits */ } return seq; } #ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -static int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefixStart, BYTE const* oLitEnd) +MEM_STATIC int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefixStart, BYTE const* oLitEnd) { size_t const windowSize = dctx->fParams.windowSize; /* No dictionary used. */ @@ -969,6 +1290,7 @@ MEM_STATIC void ZSTD_assertValidSequence( seq_t const seq, BYTE const* prefixStart, BYTE const* virtualStart) { +#if DEBUGLEVEL >= 1 size_t const windowSize = dctx->fParams.windowSize; size_t const sequenceSize = seq.litLength + seq.matchLength; BYTE const* const oLitEnd = op + seq.litLength; @@ -986,13 +1308,18 @@ MEM_STATIC void ZSTD_assertValidSequence( /* Offset must be within our window. */ assert(seq.offset <= windowSize); } +#else + (void)dctx, (void)op, (void)oend, (void)seq, (void)prefixStart, (void)virtualStart; +#endif } #endif #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG + + FORCE_INLINE_TEMPLATE size_t DONT_VECTORIZE -ZSTD_decompressSequences_body( ZSTD_DCtx* dctx, +ZSTD_decompressSequences_bodySplitLitBuffer( ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, const void* seqStart, size_t seqSize, int nbSeq, const ZSTD_longOffset_e isLongOffset, @@ -1000,21 +1327,20 @@ ZSTD_decompressSequences_body( ZSTD_DCtx* dctx, { const BYTE* ip = (const BYTE*)seqStart; const BYTE* const iend = ip + seqSize; - BYTE* const ostart = (BYTE* const)dst; + BYTE* const ostart = (BYTE*)dst; BYTE* const oend = ostart + maxDstSize; BYTE* op = ostart; const BYTE* litPtr = dctx->litPtr; - const BYTE* const litEnd = litPtr + dctx->litSize; + const BYTE* litBufferEnd = dctx->litBufferEnd; const BYTE* const prefixStart = (const BYTE*) (dctx->prefixStart); const BYTE* const vBase = (const BYTE*) (dctx->virtualStart); const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd); - DEBUGLOG(5, "ZSTD_decompressSequences_body"); + DEBUGLOG(5, "ZSTD_decompressSequences_bodySplitLitBuffer"); (void)frame; /* Regen sequences */ if (nbSeq) { seqState_t seqState; - size_t error = 0; dctx->fseEntropy = 1; { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; } RETURN_ERROR_IF( @@ -1030,70 +1356,255 @@ ZSTD_decompressSequences_body( ZSTD_DCtx* dctx, BIT_DStream_endOfBuffer < BIT_DStream_completed && BIT_DStream_completed < BIT_DStream_overflow); + /* decompress without overrunning litPtr begins */ + { + seq_t sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + /* Align the decompression loop to 32 + 16 bytes. + * + * zstd compiled with gcc-9 on an Intel i9-9900k shows 10% decompression + * speed swings based on the alignment of the decompression loop. This + * performance swing is caused by parts of the decompression loop falling + * out of the DSB. The entire decompression loop should fit in the DSB, + * when it can't we get much worse performance. You can measure if you've + * hit the good case or the bad case with this perf command for some + * compressed file test.zst: + * + * perf stat -e cycles -e instructions -e idq.all_dsb_cycles_any_uops \ + * -e idq.all_mite_cycles_any_uops -- ./zstd -tq test.zst + * + * If you see most cycles served out of the MITE you've hit the bad case. + * If you see most cycles served out of the DSB you've hit the good case. + * If it is pretty even then you may be in an okay case. + * + * This issue has been reproduced on the following CPUs: + * - Kabylake: Macbook Pro (15-inch, 2019) 2.4 GHz Intel Core i9 + * Use Instruments->Counters to get DSB/MITE cycles. + * I never got performance swings, but I was able to + * go from the good case of mostly DSB to half of the + * cycles served from MITE. + * - Coffeelake: Intel i9-9900k + * - Coffeelake: Intel i7-9700k + * + * I haven't been able to reproduce the instability or DSB misses on any + * of the following CPUS: + * - Haswell + * - Broadwell: Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GH + * - Skylake + * + * Alignment is done for each of the three major decompression loops: + * - ZSTD_decompressSequences_bodySplitLitBuffer - presplit section of the literal buffer + * - ZSTD_decompressSequences_bodySplitLitBuffer - postsplit section of the literal buffer + * - ZSTD_decompressSequences_body + * Alignment choices are made to minimize large swings on bad cases and influence on performance + * from changes external to this code, rather than to overoptimize on the current commit. + * + * If you are seeing performance stability this script can help test. + * It tests on 4 commits in zstd where I saw performance change. + * + * https://gist.github.com/terrelln/9889fc06a423fd5ca6e99351564473f4 + */ #if defined(__GNUC__) && defined(__x86_64__) - /* Align the decompression loop to 32 + 16 bytes. - * - * zstd compiled with gcc-9 on an Intel i9-9900k shows 10% decompression - * speed swings based on the alignment of the decompression loop. This - * performance swing is caused by parts of the decompression loop falling - * out of the DSB. The entire decompression loop should fit in the DSB, - * when it can't we get much worse performance. You can measure if you've - * hit the good case or the bad case with this perf command for some - * compressed file test.zst: - * - * perf stat -e cycles -e instructions -e idq.all_dsb_cycles_any_uops \ - * -e idq.all_mite_cycles_any_uops -- ./zstd -tq test.zst - * - * If you see most cycles served out of the MITE you've hit the bad case. - * If you see most cycles served out of the DSB you've hit the good case. - * If it is pretty even then you may be in an okay case. - * - * I've been able to reproduce this issue on the following CPUs: - * - Kabylake: Macbook Pro (15-inch, 2019) 2.4 GHz Intel Core i9 - * Use Instruments->Counters to get DSB/MITE cycles. - * I never got performance swings, but I was able to - * go from the good case of mostly DSB to half of the - * cycles served from MITE. - * - Coffeelake: Intel i9-9900k - * - * I haven't been able to reproduce the instability or DSB misses on any - * of the following CPUS: - * - Haswell - * - Broadwell: Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GH - * - Skylake - * - * If you are seeing performance stability this script can help test. - * It tests on 4 commits in zstd where I saw performance change. - * - * https://gist.github.com/terrelln/9889fc06a423fd5ca6e99351564473f4 - */ - __asm__(".p2align 5"); - __asm__("nop"); - __asm__(".p2align 4"); + __asm__(".p2align 6"); +# if __GNUC__ >= 7 + /* good for gcc-7, gcc-9, and gcc-11 */ + __asm__("nop"); + __asm__(".p2align 5"); + __asm__("nop"); + __asm__(".p2align 4"); +# if __GNUC__ == 8 || __GNUC__ == 10 + /* good for gcc-8 and gcc-10 */ + __asm__("nop"); + __asm__(".p2align 3"); +# endif +# endif +#endif + + /* Handle the initial state where litBuffer is currently split between dst and litExtraBuffer */ + for (; litPtr + sequence.litLength <= dctx->litBufferEnd; ) { + size_t const oneSeqSize = ZSTD_execSequenceSplitLitBuffer(op, oend, litPtr + sequence.litLength - WILDCOPY_OVERLENGTH, sequence, &litPtr, litBufferEnd, prefixStart, vBase, dictEnd); +#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) + assert(!ZSTD_isError(oneSeqSize)); + if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase); +#endif + if (UNLIKELY(ZSTD_isError(oneSeqSize))) + return oneSeqSize; + DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); + op += oneSeqSize; + if (UNLIKELY(!--nbSeq)) + break; + BIT_reloadDStream(&(seqState.DStream)); + sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + } + + /* If there are more sequences, they will need to read literals from litExtraBuffer; copy over the remainder from dst and update litPtr and litEnd */ + if (nbSeq > 0) { + const size_t leftoverLit = dctx->litBufferEnd - litPtr; + if (leftoverLit) + { + RETURN_ERROR_IF(leftoverLit > (size_t)(oend - op), dstSize_tooSmall, "remaining lit must fit within dstBuffer"); + ZSTD_safecopyDstBeforeSrc(op, litPtr, leftoverLit); + sequence.litLength -= leftoverLit; + op += leftoverLit; + } + litPtr = dctx->litExtraBuffer; + litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; + dctx->litBufferLocation = ZSTD_not_in_dst; + { + size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litBufferEnd, prefixStart, vBase, dictEnd); +#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) + assert(!ZSTD_isError(oneSeqSize)); + if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase); +#endif + if (UNLIKELY(ZSTD_isError(oneSeqSize))) + return oneSeqSize; + DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); + op += oneSeqSize; + if (--nbSeq) + BIT_reloadDStream(&(seqState.DStream)); + } + } + } + + if (nbSeq > 0) /* there is remaining lit from extra buffer */ + { + +#if defined(__GNUC__) && defined(__x86_64__) + __asm__(".p2align 6"); + __asm__("nop"); +# if __GNUC__ != 7 + /* worse for gcc-7 better for gcc-8, gcc-9, and gcc-10 and clang */ + __asm__(".p2align 4"); + __asm__("nop"); + __asm__(".p2align 3"); +# elif __GNUC__ >= 11 + __asm__(".p2align 3"); +# else + __asm__(".p2align 5"); + __asm__("nop"); + __asm__(".p2align 3"); +# endif +#endif + + for (; ; ) { + seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litBufferEnd, prefixStart, vBase, dictEnd); +#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) + assert(!ZSTD_isError(oneSeqSize)); + if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase); +#endif + if (UNLIKELY(ZSTD_isError(oneSeqSize))) + return oneSeqSize; + DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); + op += oneSeqSize; + if (UNLIKELY(!--nbSeq)) + break; + BIT_reloadDStream(&(seqState.DStream)); + } + } + + /* check if reached exact end */ + DEBUGLOG(5, "ZSTD_decompressSequences_bodySplitLitBuffer: after decode loop, remaining nbSeq : %i", nbSeq); + RETURN_ERROR_IF(nbSeq, corruption_detected, ""); + RETURN_ERROR_IF(BIT_reloadDStream(&seqState.DStream) < BIT_DStream_completed, corruption_detected, ""); + /* save reps for next block */ + { U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); } + } + + /* last literal segment */ + if (dctx->litBufferLocation == ZSTD_split) /* split hasn't been reached yet, first get dst then copy litExtraBuffer */ + { + size_t const lastLLSize = litBufferEnd - litPtr; + RETURN_ERROR_IF(lastLLSize > (size_t)(oend - op), dstSize_tooSmall, ""); + if (op != NULL) { + ZSTD_memmove(op, litPtr, lastLLSize); + op += lastLLSize; + } + litPtr = dctx->litExtraBuffer; + litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; + dctx->litBufferLocation = ZSTD_not_in_dst; + } + { size_t const lastLLSize = litBufferEnd - litPtr; + RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, ""); + if (op != NULL) { + ZSTD_memcpy(op, litPtr, lastLLSize); + op += lastLLSize; + } + } + + return op-ostart; +} + +FORCE_INLINE_TEMPLATE size_t +DONT_VECTORIZE +ZSTD_decompressSequences_body(ZSTD_DCtx* dctx, + void* dst, size_t maxDstSize, + const void* seqStart, size_t seqSize, int nbSeq, + const ZSTD_longOffset_e isLongOffset, + const int frame) +{ + const BYTE* ip = (const BYTE*)seqStart; + const BYTE* const iend = ip + seqSize; + BYTE* const ostart = (BYTE*)dst; + BYTE* const oend = dctx->litBufferLocation == ZSTD_not_in_dst ? ostart + maxDstSize : dctx->litBuffer; + BYTE* op = ostart; + const BYTE* litPtr = dctx->litPtr; + const BYTE* const litEnd = litPtr + dctx->litSize; + const BYTE* const prefixStart = (const BYTE*)(dctx->prefixStart); + const BYTE* const vBase = (const BYTE*)(dctx->virtualStart); + const BYTE* const dictEnd = (const BYTE*)(dctx->dictEnd); + DEBUGLOG(5, "ZSTD_decompressSequences_body"); + (void)frame; + + /* Regen sequences */ + if (nbSeq) { + seqState_t seqState; + dctx->fseEntropy = 1; + { U32 i; for (i = 0; i < ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; } + RETURN_ERROR_IF( + ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend - ip)), + corruption_detected, ""); + ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr); + ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr); + ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr); + assert(dst != NULL); + + ZSTD_STATIC_ASSERT( + BIT_DStream_unfinished < BIT_DStream_completed && + BIT_DStream_endOfBuffer < BIT_DStream_completed && + BIT_DStream_completed < BIT_DStream_overflow); + +#if defined(__GNUC__) && defined(__x86_64__) + __asm__(".p2align 6"); + __asm__("nop"); +# if __GNUC__ >= 7 + __asm__(".p2align 5"); + __asm__("nop"); + __asm__(".p2align 3"); +# else + __asm__(".p2align 4"); + __asm__("nop"); + __asm__(".p2align 3"); +# endif #endif + for ( ; ; ) { - seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset, ZSTD_p_noPrefetch); + seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, prefixStart, vBase, dictEnd); #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) assert(!ZSTD_isError(oneSeqSize)); if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase); #endif + if (UNLIKELY(ZSTD_isError(oneSeqSize))) + return oneSeqSize; DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); + op += oneSeqSize; + if (UNLIKELY(!--nbSeq)) + break; BIT_reloadDStream(&(seqState.DStream)); - /* gcc and clang both don't like early returns in this loop. - * gcc doesn't like early breaks either. - * Instead save an error and report it at the end. - * When there is an error, don't increment op, so we don't - * overwrite. - */ - if (UNLIKELY(ZSTD_isError(oneSeqSize))) error = oneSeqSize; - else op += oneSeqSize; - if (UNLIKELY(!--nbSeq)) break; } /* check if reached exact end */ DEBUGLOG(5, "ZSTD_decompressSequences_body: after decode loop, remaining nbSeq : %i", nbSeq); - if (ZSTD_isError(error)) return error; RETURN_ERROR_IF(nbSeq, corruption_detected, ""); RETURN_ERROR_IF(BIT_reloadDStream(&seqState.DStream) < BIT_DStream_completed, corruption_detected, ""); /* save reps for next block */ @@ -1104,7 +1615,7 @@ ZSTD_decompressSequences_body( ZSTD_DCtx* dctx, { size_t const lastLLSize = litEnd - litPtr; RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, ""); if (op != NULL) { - memcpy(op, litPtr, lastLLSize); + ZSTD_memcpy(op, litPtr, lastLLSize); op += lastLLSize; } } @@ -1121,9 +1632,37 @@ ZSTD_decompressSequences_default(ZSTD_DCtx* dctx, { return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); } + +static size_t +ZSTD_decompressSequencesSplitLitBuffer_default(ZSTD_DCtx* dctx, + void* dst, size_t maxDstSize, + const void* seqStart, size_t seqSize, int nbSeq, + const ZSTD_longOffset_e isLongOffset, + const int frame) +{ + return ZSTD_decompressSequences_bodySplitLitBuffer(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); +} #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */ #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT + +FORCE_INLINE_TEMPLATE size_t +ZSTD_prefetchMatch(size_t prefetchPos, seq_t const sequence, + const BYTE* const prefixStart, const BYTE* const dictEnd) +{ + prefetchPos += sequence.litLength; + { const BYTE* const matchBase = (sequence.offset > prefetchPos) ? dictEnd : prefixStart; + 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. + * No consequence though : memory address is only used for prefetching, not for dereferencing */ + PREFETCH_L1(match); PREFETCH_L1(match+CACHELINE_SIZE); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */ + } + return prefetchPos + sequence.matchLength; +} + +/* This decoding function employs prefetching + * to reduce latency impact of cache misses. + * It's generally employed when block contains a significant portion of long-distance matches + * or when coupled with a "cold" dictionary */ FORCE_INLINE_TEMPLATE size_t ZSTD_decompressSequencesLong_body( ZSTD_DCtx* dctx, @@ -1134,11 +1673,11 @@ ZSTD_decompressSequencesLong_body( { const BYTE* ip = (const BYTE*)seqStart; const BYTE* const iend = ip + seqSize; - BYTE* const ostart = (BYTE* const)dst; - BYTE* const oend = ostart + maxDstSize; + BYTE* const ostart = (BYTE*)dst; + BYTE* const oend = dctx->litBufferLocation == ZSTD_in_dst ? dctx->litBuffer : ostart + maxDstSize; BYTE* op = ostart; const BYTE* litPtr = dctx->litPtr; - const BYTE* const litEnd = litPtr + dctx->litSize; + const BYTE* litBufferEnd = dctx->litBufferEnd; const BYTE* const prefixStart = (const BYTE*) (dctx->prefixStart); const BYTE* const dictStart = (const BYTE*) (dctx->virtualStart); const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd); @@ -1146,18 +1685,17 @@ ZSTD_decompressSequencesLong_body( /* Regen sequences */ if (nbSeq) { -#define STORED_SEQS 4 +#define STORED_SEQS 8 #define STORED_SEQS_MASK (STORED_SEQS-1) -#define ADVANCED_SEQS 4 +#define ADVANCED_SEQS STORED_SEQS seq_t sequences[STORED_SEQS]; int const seqAdvance = MIN(nbSeq, ADVANCED_SEQS); seqState_t seqState; int seqNb; + size_t prefetchPos = (size_t)(op-prefixStart); /* track position relative to prefixStart */ + dctx->fseEntropy = 1; { int i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; } - seqState.prefixStart = prefixStart; - seqState.pos = (size_t)(op-prefixStart); - seqState.dictEnd = dictEnd; assert(dst != NULL); assert(iend >= ip); RETURN_ERROR_IF( @@ -1169,36 +1707,100 @@ ZSTD_decompressSequencesLong_body( /* prepare in advance */ for (seqNb=0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && (seqNb<seqAdvance); seqNb++) { - sequences[seqNb] = ZSTD_decodeSequence(&seqState, isLongOffset, ZSTD_p_prefetch); - PREFETCH_L1(sequences[seqNb].match); PREFETCH_L1(sequences[seqNb].match + sequences[seqNb].matchLength - 1); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */ + seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + prefetchPos = ZSTD_prefetchMatch(prefetchPos, sequence, prefixStart, dictEnd); + sequences[seqNb] = sequence; } RETURN_ERROR_IF(seqNb<seqAdvance, corruption_detected, ""); - /* decode and decompress */ - for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && (seqNb<nbSeq) ; seqNb++) { - seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset, ZSTD_p_prefetch); - size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequences[(seqNb-ADVANCED_SEQS) & STORED_SEQS_MASK], &litPtr, litEnd, prefixStart, dictStart, dictEnd); + /* decompress without stomping litBuffer */ + for (; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && (seqNb < nbSeq); seqNb++) { + seq_t sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + size_t oneSeqSize; + + if (dctx->litBufferLocation == ZSTD_split && litPtr + sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK].litLength > dctx->litBufferEnd) + { + /* lit buffer is reaching split point, empty out the first buffer and transition to litExtraBuffer */ + const size_t leftoverLit = dctx->litBufferEnd - litPtr; + if (leftoverLit) + { + RETURN_ERROR_IF(leftoverLit > (size_t)(oend - op), dstSize_tooSmall, "remaining lit must fit within dstBuffer"); + ZSTD_safecopyDstBeforeSrc(op, litPtr, leftoverLit); + sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK].litLength -= leftoverLit; + op += leftoverLit; + } + litPtr = dctx->litExtraBuffer; + litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; + dctx->litBufferLocation = ZSTD_not_in_dst; + oneSeqSize = ZSTD_execSequence(op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd); #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) - assert(!ZSTD_isError(oneSeqSize)); - if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[(seqNb-ADVANCED_SEQS) & STORED_SEQS_MASK], prefixStart, dictStart); + assert(!ZSTD_isError(oneSeqSize)); + if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], prefixStart, dictStart); #endif - if (ZSTD_isError(oneSeqSize)) return oneSeqSize; - PREFETCH_L1(sequence.match); PREFETCH_L1(sequence.match + sequence.matchLength - 1); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */ - sequences[seqNb & STORED_SEQS_MASK] = sequence; - op += oneSeqSize; + if (ZSTD_isError(oneSeqSize)) return oneSeqSize; + + prefetchPos = ZSTD_prefetchMatch(prefetchPos, sequence, prefixStart, dictEnd); + sequences[seqNb & STORED_SEQS_MASK] = sequence; + op += oneSeqSize; + } + else + { + /* lit buffer is either wholly contained in first or second split, or not split at all*/ + oneSeqSize = dctx->litBufferLocation == ZSTD_split ? + 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) : + ZSTD_execSequence(op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd); +#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) + assert(!ZSTD_isError(oneSeqSize)); + if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], prefixStart, dictStart); +#endif + if (ZSTD_isError(oneSeqSize)) return oneSeqSize; + + prefetchPos = ZSTD_prefetchMatch(prefetchPos, sequence, prefixStart, dictEnd); + sequences[seqNb & STORED_SEQS_MASK] = sequence; + op += oneSeqSize; + } } RETURN_ERROR_IF(seqNb<nbSeq, corruption_detected, ""); /* finish queue */ seqNb -= seqAdvance; for ( ; seqNb<nbSeq ; seqNb++) { - size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequences[seqNb&STORED_SEQS_MASK], &litPtr, litEnd, prefixStart, dictStart, dictEnd); + seq_t *sequence = &(sequences[seqNb&STORED_SEQS_MASK]); + if (dctx->litBufferLocation == ZSTD_split && litPtr + sequence->litLength > dctx->litBufferEnd) + { + const size_t leftoverLit = dctx->litBufferEnd - litPtr; + if (leftoverLit) + { + RETURN_ERROR_IF(leftoverLit > (size_t)(oend - op), dstSize_tooSmall, "remaining lit must fit within dstBuffer"); + ZSTD_safecopyDstBeforeSrc(op, litPtr, leftoverLit); + sequence->litLength -= leftoverLit; + op += leftoverLit; + } + litPtr = dctx->litExtraBuffer; + litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; + dctx->litBufferLocation = ZSTD_not_in_dst; + { + size_t const oneSeqSize = ZSTD_execSequence(op, oend, *sequence, &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd); #if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) - assert(!ZSTD_isError(oneSeqSize)); - if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[seqNb&STORED_SEQS_MASK], prefixStart, dictStart); + assert(!ZSTD_isError(oneSeqSize)); + if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[seqNb&STORED_SEQS_MASK], prefixStart, dictStart); #endif - if (ZSTD_isError(oneSeqSize)) return oneSeqSize; - op += oneSeqSize; + if (ZSTD_isError(oneSeqSize)) return oneSeqSize; + op += oneSeqSize; + } + } + else + { + size_t const oneSeqSize = dctx->litBufferLocation == ZSTD_split ? + ZSTD_execSequenceSplitLitBuffer(op, oend, litPtr + sequence->litLength - WILDCOPY_OVERLENGTH, *sequence, &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd) : + ZSTD_execSequence(op, oend, *sequence, &litPtr, litBufferEnd, prefixStart, dictStart, dictEnd); +#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) + assert(!ZSTD_isError(oneSeqSize)); + if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[seqNb&STORED_SEQS_MASK], prefixStart, dictStart); +#endif + if (ZSTD_isError(oneSeqSize)) return oneSeqSize; + op += oneSeqSize; + } } /* save reps for next block */ @@ -1206,10 +1808,21 @@ ZSTD_decompressSequencesLong_body( } /* last literal segment */ - { size_t const lastLLSize = litEnd - litPtr; + if (dctx->litBufferLocation == ZSTD_split) /* first deplete literal buffer in dst, then copy litExtraBuffer */ + { + size_t const lastLLSize = litBufferEnd - litPtr; + RETURN_ERROR_IF(lastLLSize > (size_t)(oend - op), dstSize_tooSmall, ""); + if (op != NULL) { + ZSTD_memmove(op, litPtr, lastLLSize); + op += lastLLSize; + } + litPtr = dctx->litExtraBuffer; + litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; + } + { size_t const lastLLSize = litBufferEnd - litPtr; RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, ""); if (op != NULL) { - memcpy(op, litPtr, lastLLSize); + ZSTD_memmove(op, litPtr, lastLLSize); op += lastLLSize; } } @@ -1233,7 +1846,7 @@ ZSTD_decompressSequencesLong_default(ZSTD_DCtx* dctx, #if DYNAMIC_BMI2 #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG -static TARGET_ATTRIBUTE("bmi2") size_t +static BMI2_TARGET_ATTRIBUTE size_t DONT_VECTORIZE ZSTD_decompressSequences_bmi2(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, @@ -1243,10 +1856,20 @@ ZSTD_decompressSequences_bmi2(ZSTD_DCtx* dctx, { return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); } +static BMI2_TARGET_ATTRIBUTE size_t +DONT_VECTORIZE +ZSTD_decompressSequencesSplitLitBuffer_bmi2(ZSTD_DCtx* dctx, + void* dst, size_t maxDstSize, + const void* seqStart, size_t seqSize, int nbSeq, + const ZSTD_longOffset_e isLongOffset, + const int frame) +{ + return ZSTD_decompressSequences_bodySplitLitBuffer(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); +} #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */ #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT -static TARGET_ATTRIBUTE("bmi2") size_t +static BMI2_TARGET_ATTRIBUTE size_t ZSTD_decompressSequencesLong_bmi2(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, const void* seqStart, size_t seqSize, int nbSeq, @@ -1275,11 +1898,25 @@ ZSTD_decompressSequences(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, { DEBUGLOG(5, "ZSTD_decompressSequences"); #if DYNAMIC_BMI2 - if (dctx->bmi2) { + if (ZSTD_DCtx_get_bmi2(dctx)) { return ZSTD_decompressSequences_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); } #endif - return ZSTD_decompressSequences_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequences_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); +} +static size_t +ZSTD_decompressSequencesSplitLitBuffer(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize, + const void* seqStart, size_t seqSize, int nbSeq, + const ZSTD_longOffset_e isLongOffset, + const int frame) +{ + DEBUGLOG(5, "ZSTD_decompressSequencesSplitLitBuffer"); +#if DYNAMIC_BMI2 + if (ZSTD_DCtx_get_bmi2(dctx)) { + return ZSTD_decompressSequencesSplitLitBuffer_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + } +#endif + return ZSTD_decompressSequencesSplitLitBuffer_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); } #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */ @@ -1299,7 +1936,7 @@ ZSTD_decompressSequencesLong(ZSTD_DCtx* dctx, { DEBUGLOG(5, "ZSTD_decompressSequencesLong"); #if DYNAMIC_BMI2 - if (dctx->bmi2) { + if (ZSTD_DCtx_get_bmi2(dctx)) { return ZSTD_decompressSequencesLong_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); } #endif @@ -1340,7 +1977,7 @@ ZSTD_getLongOffsetsShare(const ZSTD_seqSymbol* offTable) size_t ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, - const void* src, size_t srcSize, const int frame) + const void* src, size_t srcSize, const int frame, const streaming_operation streaming) { /* blockType == blockCompressed */ const BYTE* ip = (const BYTE*)src; /* isLongOffset must be true if there are long offsets. @@ -1355,7 +1992,7 @@ ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx, RETURN_ERROR_IF(srcSize >= ZSTD_BLOCKSIZE_MAX, srcSize_wrong, ""); /* Decode literals section */ - { size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize); + { size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize, dst, dstCapacity, streaming); DEBUGLOG(5, "ZSTD_decodeLiteralsBlock : %u", (U32)litCSize); if (ZSTD_isError(litCSize)) return litCSize; ip += litCSize; @@ -1403,15 +2040,18 @@ ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx, #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG /* else */ - return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); + if (dctx->litBufferLocation == ZSTD_split) + return ZSTD_decompressSequencesSplitLitBuffer(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); + else + return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); #endif } } -void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst) +void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize) { - if (dst != dctx->previousDstEnd) { /* not contiguous */ + if (dst != dctx->previousDstEnd && dstSize > 0) { /* not contiguous */ dctx->dictEnd = dctx->previousDstEnd; dctx->virtualStart = (const char*)dst - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->prefixStart)); dctx->prefixStart = dst; @@ -1425,8 +2065,8 @@ size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, const void* src, size_t srcSize) { size_t dSize; - ZSTD_checkContinuity(dctx, dst); - dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 0); + ZSTD_checkContinuity(dctx, dst, dstCapacity); + dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 0, not_streaming); dctx->previousDstEnd = (char*)dst + dSize; return dSize; } |