diff options
Diffstat (limited to 'lib/zstd/decompress/zstd_decompress_block.c')
| -rw-r--r-- | lib/zstd/decompress/zstd_decompress_block.c | 724 |
1 files changed, 431 insertions, 293 deletions
diff --git a/lib/zstd/decompress/zstd_decompress_block.c b/lib/zstd/decompress/zstd_decompress_block.c index c1913b8e7c89..710eb0ffd5a3 100644 --- a/lib/zstd/decompress/zstd_decompress_block.c +++ b/lib/zstd/decompress/zstd_decompress_block.c @@ -1,5 +1,6 @@ +// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause /* - * Copyright (c) Yann Collet, Facebook, Inc. + * Copyright (c) Meta Platforms, Inc. and affiliates. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the @@ -20,12 +21,12 @@ #include "../common/mem.h" /* low level memory routines */ #define FSE_STATIC_LINKING_ONLY #include "../common/fse.h" -#define HUF_STATIC_LINKING_ONLY #include "../common/huf.h" #include "../common/zstd_internal.h" #include "zstd_decompress_internal.h" /* ZSTD_DCtx */ #include "zstd_ddict.h" /* ZSTD_DDictDictContent */ #include "zstd_decompress_block.h" +#include "../common/bits.h" /* ZSTD_highbit32 */ /*_******************************************************* * Macros @@ -51,6 +52,13 @@ static void ZSTD_copy4(void* dst, const void* src) { ZSTD_memcpy(dst, src, 4); } * Block decoding ***************************************************************/ +static size_t ZSTD_blockSizeMax(ZSTD_DCtx const* dctx) +{ + size_t const blockSizeMax = dctx->isFrameDecompression ? dctx->fParams.blockSizeMax : ZSTD_BLOCKSIZE_MAX; + assert(blockSizeMax <= ZSTD_BLOCKSIZE_MAX); + return blockSizeMax; +} + /*! ZSTD_getcBlockSize() : * Provides the size of compressed block from block header `src` */ size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, @@ -73,41 +81,49 @@ size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, 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; + size_t const blockSizeMax = ZSTD_blockSizeMax(dctx); + assert(litSize <= blockSizeMax); + assert(dctx->isFrameDecompression || streaming == not_streaming); + assert(expectedWriteSize <= blockSizeMax); + if (streaming == not_streaming && dstCapacity > blockSizeMax + WILDCOPY_OVERLENGTH + litSize + WILDCOPY_OVERLENGTH) { + /* If we aren't streaming, we can just put the literals after the output + * of the current block. We don't need to worry about overwriting the + * extDict of our window, because it doesn't exist. + * So if we have space after the end of the block, just put it there. + */ + dctx->litBuffer = (BYTE*)dst + blockSizeMax + 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 */ + } else if (litSize <= ZSTD_LITBUFFEREXTRASIZE) { + /* Literals fit entirely within the extra buffer, put them there to avoid + * having to split the literals. + */ + dctx->litBuffer = dctx->litExtraBuffer; + dctx->litBufferEnd = dctx->litBuffer + litSize; + dctx->litBufferLocation = ZSTD_not_in_dst; + } else { + assert(blockSizeMax > ZSTD_LITBUFFEREXTRASIZE); + /* Literals must be split between the output block and the extra lit + * buffer. We fill the extra lit buffer with the tail of the literals, + * and put the rest of the literals at the end of the block, with + * WILDCOPY_OVERLENGTH of buffer room to allow for overreads. + * This MUST not write more than our maxBlockSize beyond dst, because in + * streaming mode, that could overwrite part of our extDict window. + */ 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 */ + } else { + /* initially this will be stored entirely in dst during huffman decoding, it will partially be 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; + assert(dctx->litBufferEnd <= (BYTE*)dst + expectedWriteSize); } } -/* Hidden declaration for fullbench */ -size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, - 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 @@ -116,7 +132,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, * * @return : nb of bytes read from src (< srcSize ) * note : symbol not declared but exposed for fullbench */ -size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, +static size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, const void* src, size_t srcSize, /* note : srcSize < BLOCKSIZE */ void* dst, size_t dstCapacity, const streaming_operation streaming) { @@ -124,7 +140,8 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, RETURN_ERROR_IF(srcSize < MIN_CBLOCK_SIZE, corruption_detected, ""); { const BYTE* const istart = (const BYTE*) src; - symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3); + SymbolEncodingType_e const litEncType = (SymbolEncodingType_e)(istart[0] & 3); + size_t const blockSizeMax = ZSTD_blockSizeMax(dctx); switch(litEncType) { @@ -134,13 +151,16 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, 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"); + RETURN_ERROR_IF(srcSize < 5, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 2; here we need up to 5 for case 3"); { size_t lhSize, litSize, litCSize; U32 singleStream=0; U32 const lhlCode = (istart[0] >> 2) & 3; U32 const lhc = MEM_readLE32(istart); size_t hufSuccess; - size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); + size_t expectedWriteSize = MIN(blockSizeMax, dstCapacity); + int const flags = 0 + | (ZSTD_DCtx_get_bmi2(dctx) ? HUF_flags_bmi2 : 0) + | (dctx->disableHufAsm ? HUF_flags_disableAsm : 0); switch(lhlCode) { case 0: case 1: default: /* note : default is impossible, since lhlCode into [0..3] */ @@ -164,7 +184,11 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, 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(litSize > blockSizeMax, corruption_detected, ""); + if (!singleStream) + RETURN_ERROR_IF(litSize < MIN_LITERALS_FOR_4_STREAMS, literals_headerWrong, + "Not enough literals (%zu) for the 4-streams mode (min %u)", + litSize, MIN_LITERALS_FOR_4_STREAMS); RETURN_ERROR_IF(litCSize + lhSize > srcSize, corruption_detected, ""); RETURN_ERROR_IF(expectedWriteSize < litSize , dstSize_tooSmall, ""); ZSTD_allocateLiteralsBuffer(dctx, dst, dstCapacity, litSize, streaming, expectedWriteSize, 0); @@ -176,13 +200,14 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, if (litEncType==set_repeat) { if (singleStream) { - hufSuccess = HUF_decompress1X_usingDTable_bmi2( + hufSuccess = HUF_decompress1X_usingDTable( dctx->litBuffer, litSize, istart+lhSize, litCSize, - dctx->HUFptr, ZSTD_DCtx_get_bmi2(dctx)); + dctx->HUFptr, flags); } else { - hufSuccess = HUF_decompress4X_usingDTable_bmi2( + assert(litSize >= MIN_LITERALS_FOR_4_STREAMS); + hufSuccess = HUF_decompress4X_usingDTable( dctx->litBuffer, litSize, istart+lhSize, litCSize, - dctx->HUFptr, ZSTD_DCtx_get_bmi2(dctx)); + dctx->HUFptr, flags); } } else { if (singleStream) { @@ -190,26 +215,28 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, hufSuccess = HUF_decompress1X_DCtx_wksp( dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize, dctx->workspace, - sizeof(dctx->workspace)); + sizeof(dctx->workspace), flags); #else - hufSuccess = HUF_decompress1X1_DCtx_wksp_bmi2( + hufSuccess = HUF_decompress1X1_DCtx_wksp( dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize, dctx->workspace, - sizeof(dctx->workspace), ZSTD_DCtx_get_bmi2(dctx)); + sizeof(dctx->workspace), flags); #endif } else { - hufSuccess = HUF_decompress4X_hufOnly_wksp_bmi2( + hufSuccess = HUF_decompress4X_hufOnly_wksp( dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize, dctx->workspace, - sizeof(dctx->workspace), ZSTD_DCtx_get_bmi2(dctx)); + sizeof(dctx->workspace), flags); } } if (dctx->litBufferLocation == ZSTD_split) { + assert(litSize > ZSTD_LITBUFFEREXTRASIZE); 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; + assert(dctx->litBufferEnd <= (BYTE*)dst + blockSizeMax); } RETURN_ERROR_IF(HUF_isError(hufSuccess), corruption_detected, ""); @@ -224,7 +251,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, case set_basic: { size_t litSize, lhSize; U32 const lhlCode = ((istart[0]) >> 2) & 3; - size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); + size_t expectedWriteSize = MIN(blockSizeMax, dstCapacity); switch(lhlCode) { case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */ @@ -237,11 +264,13 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, break; case 3: lhSize = 3; + RETURN_ERROR_IF(srcSize<3, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 2; here we need lhSize = 3"); litSize = MEM_readLE24(istart) >> 4; break; } RETURN_ERROR_IF(litSize > 0 && dst == NULL, dstSize_tooSmall, "NULL not handled"); + RETURN_ERROR_IF(litSize > blockSizeMax, corruption_detected, ""); 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 */ @@ -270,7 +299,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, case set_rle: { U32 const lhlCode = ((istart[0]) >> 2) & 3; size_t litSize, lhSize; - size_t expectedWriteSize = MIN(ZSTD_BLOCKSIZE_MAX, dstCapacity); + size_t expectedWriteSize = MIN(blockSizeMax, dstCapacity); switch(lhlCode) { case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */ @@ -279,16 +308,17 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, break; case 1: lhSize = 2; + RETURN_ERROR_IF(srcSize<3, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 2; here we need lhSize+1 = 3"); litSize = MEM_readLE16(istart) >> 4; break; case 3: lhSize = 3; + RETURN_ERROR_IF(srcSize<4, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 2; here we need lhSize+1 = 4"); litSize = MEM_readLE24(istart) >> 4; - 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, ""); + RETURN_ERROR_IF(litSize > blockSizeMax, corruption_detected, ""); RETURN_ERROR_IF(expectedWriteSize < litSize, dstSize_tooSmall, ""); ZSTD_allocateLiteralsBuffer(dctx, dst, dstCapacity, litSize, streaming, expectedWriteSize, 1); if (dctx->litBufferLocation == ZSTD_split) @@ -310,6 +340,18 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, } } +/* Hidden declaration for fullbench */ +size_t ZSTD_decodeLiteralsBlock_wrapper(ZSTD_DCtx* dctx, + const void* src, size_t srcSize, + void* dst, size_t dstCapacity); +size_t ZSTD_decodeLiteralsBlock_wrapper(ZSTD_DCtx* dctx, + const void* src, size_t srcSize, + void* dst, size_t dstCapacity) +{ + dctx->isFrameDecompression = 0; + return ZSTD_decodeLiteralsBlock(dctx, src, srcSize, dst, dstCapacity, not_streaming); +} + /* Default FSE distribution tables. * These are pre-calculated FSE decoding tables using default distributions as defined in specification : * https://github.com/facebook/zstd/blob/release/doc/zstd_compression_format.md#default-distributions @@ -317,7 +359,7 @@ size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx, * - start from default distributions, present in /lib/common/zstd_internal.h * - generate tables normally, using ZSTD_buildFSETable() * - printout the content of tables - * - pretify output, report below, test with fuzzer to ensure it's correct */ + * - prettify output, report below, test with fuzzer to ensure it's correct */ /* Default FSE distribution table for Literal Lengths */ static const ZSTD_seqSymbol LL_defaultDTable[(1<<LL_DEFAULTNORMLOG)+1] = { @@ -506,14 +548,15 @@ void ZSTD_buildFSETable_body(ZSTD_seqSymbol* dt, for (i = 8; i < n; i += 8) { MEM_write64(spread + pos + i, sv); } - pos += n; + assert(n>=0); + pos += (size_t)n; } } /* Now we spread those positions across the table. - * The benefit of doing it in two stages is that we avoid the the + * The benefit of doing it in two stages is that we avoid 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. + * We unroll the loop twice, since that is what empirically worked best. */ { size_t position = 0; @@ -540,7 +583,7 @@ void ZSTD_buildFSETable_body(ZSTD_seqSymbol* dt, for (i=0; i<n; i++) { tableDecode[position].baseValue = s; position = (position + step) & tableMask; - while (position > highThreshold) position = (position + step) & tableMask; /* lowprob area */ + while (UNLIKELY(position > highThreshold)) position = (position + step) & tableMask; /* lowprob area */ } } assert(position == 0); /* position must reach all cells once, otherwise normalizedCounter is incorrect */ } @@ -551,7 +594,7 @@ void ZSTD_buildFSETable_body(ZSTD_seqSymbol* dt, 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].nbBits = (BYTE) (tableLog - ZSTD_highbit32(nextState) ); tableDecode[u].nextState = (U16) ( (nextState << tableDecode[u].nbBits) - tableSize); assert(nbAdditionalBits[symbol] < 255); tableDecode[u].nbAdditionalBits = nbAdditionalBits[symbol]; @@ -603,7 +646,7 @@ void ZSTD_buildFSETable(ZSTD_seqSymbol* dt, * @return : nb bytes read from src, * or an error code if it fails */ static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymbol** DTablePtr, - symbolEncodingType_e type, unsigned max, U32 maxLog, + SymbolEncodingType_e type, unsigned max, U32 maxLog, const void* src, size_t srcSize, const U32* baseValue, const U8* nbAdditionalBits, const ZSTD_seqSymbol* defaultTable, U32 flagRepeatTable, @@ -664,11 +707,6 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr, /* SeqHead */ nbSeq = *ip++; - if (!nbSeq) { - *nbSeqPtr=0; - RETURN_ERROR_IF(srcSize != 1, srcSize_wrong, ""); - return 1; - } if (nbSeq > 0x7F) { if (nbSeq == 0xFF) { RETURN_ERROR_IF(ip+2 > iend, srcSize_wrong, ""); @@ -681,11 +719,19 @@ size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr, } *nbSeqPtr = nbSeq; + if (nbSeq == 0) { + /* No sequence : section ends immediately */ + RETURN_ERROR_IF(ip != iend, corruption_detected, + "extraneous data present in the Sequences section"); + return (size_t)(ip - istart); + } + /* FSE table descriptors */ RETURN_ERROR_IF(ip+1 > iend, srcSize_wrong, ""); /* minimum possible size: 1 byte for symbol encoding types */ - { symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip >> 6); - symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip >> 4) & 3); - symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip >> 2) & 3); + RETURN_ERROR_IF(*ip & 3, corruption_detected, ""); /* The last field, Reserved, must be all-zeroes. */ + { SymbolEncodingType_e const LLtype = (SymbolEncodingType_e)(*ip >> 6); + SymbolEncodingType_e const OFtype = (SymbolEncodingType_e)((*ip >> 4) & 3); + SymbolEncodingType_e const MLtype = (SymbolEncodingType_e)((*ip >> 2) & 3); ip++; /* Build DTables */ @@ -829,7 +875,7 @@ static void ZSTD_safecopy(BYTE* op, const BYTE* const oend_w, BYTE const* ip, pt /* 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) { +static void ZSTD_safecopyDstBeforeSrc(BYTE* op, const BYTE* ip, ptrdiff_t length) { ptrdiff_t const diff = op - ip; BYTE* const oend = op + length; @@ -858,6 +904,7 @@ static void ZSTD_safecopyDstBeforeSrc(BYTE* op, BYTE const* ip, ptrdiff_t length * to be optimized for many small sequences, since those fall into ZSTD_execSequence(). */ FORCE_NOINLINE +ZSTD_ALLOW_POINTER_OVERFLOW_ATTR size_t ZSTD_execSequenceEnd(BYTE* op, BYTE* const oend, seq_t sequence, const BYTE** litPtr, const BYTE* const litLimit, @@ -905,6 +952,7 @@ size_t ZSTD_execSequenceEnd(BYTE* op, * 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 +ZSTD_ALLOW_POINTER_OVERFLOW_ATTR size_t ZSTD_execSequenceEndSplitLitBuffer(BYTE* op, BYTE* const oend, const BYTE* const oend_w, seq_t sequence, const BYTE** litPtr, const BYTE* const litLimit, @@ -950,6 +998,7 @@ size_t ZSTD_execSequenceEndSplitLitBuffer(BYTE* op, } HINT_INLINE +ZSTD_ALLOW_POINTER_OVERFLOW_ATTR size_t ZSTD_execSequence(BYTE* op, BYTE* const oend, seq_t sequence, const BYTE** litPtr, const BYTE* const litLimit, @@ -964,6 +1013,11 @@ size_t ZSTD_execSequence(BYTE* op, assert(op != NULL /* Precondition */); assert(oend_w < oend /* No underflow */); + +#if defined(__aarch64__) + /* prefetch sequence starting from match that will be used for copy later */ + PREFETCH_L1(match); +#endif /* Handle edge cases in a slow path: * - Read beyond end of literals * - Match end is within WILDCOPY_OVERLIMIT of oend @@ -1043,6 +1097,7 @@ size_t ZSTD_execSequence(BYTE* op, } HINT_INLINE +ZSTD_ALLOW_POINTER_OVERFLOW_ATTR size_t ZSTD_execSequenceSplitLitBuffer(BYTE* op, BYTE* const oend, const BYTE* const oend_w, seq_t sequence, const BYTE** litPtr, const BYTE* const litLimit, @@ -1154,7 +1209,7 @@ ZSTD_updateFseStateWithDInfo(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, U16 } /* We need to add at most (ZSTD_WINDOWLOG_MAX_32 - 1) bits to read the maximum - * offset bits. But we can only read at most (STREAM_ACCUMULATOR_MIN_32 - 1) + * offset bits. But we can only read at most STREAM_ACCUMULATOR_MIN_32 * bits before reloading. This value is the maximum number of bytes we read * after reloading when we are decoding long offsets. */ @@ -1165,13 +1220,37 @@ ZSTD_updateFseStateWithDInfo(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, U16 typedef enum { ZSTD_lo_isRegularOffset, ZSTD_lo_isLongOffset=1 } ZSTD_longOffset_e; +/* + * ZSTD_decodeSequence(): + * @p longOffsets : tells the decoder to reload more bit while decoding large offsets + * only used in 32-bit mode + * @return : Sequence (litL + matchL + offset) + */ FORCE_INLINE_TEMPLATE seq_t -ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) +ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets, const int isLastSeq) { seq_t seq; + /* + * ZSTD_seqSymbol is a 64 bits wide structure. + * It can be loaded in one operation + * and its fields extracted by simply shifting or bit-extracting on aarch64. + * GCC doesn't recognize this and generates more unnecessary ldr/ldrb/ldrh + * operations that cause performance drop. This can be avoided by using this + * ZSTD_memcpy hack. + */ +#if defined(__aarch64__) && (defined(__GNUC__) && !defined(__clang__)) + ZSTD_seqSymbol llDInfoS, mlDInfoS, ofDInfoS; + ZSTD_seqSymbol* const llDInfo = &llDInfoS; + ZSTD_seqSymbol* const mlDInfo = &mlDInfoS; + ZSTD_seqSymbol* const ofDInfo = &ofDInfoS; + ZSTD_memcpy(llDInfo, seqState->stateLL.table + seqState->stateLL.state, sizeof(ZSTD_seqSymbol)); + ZSTD_memcpy(mlDInfo, seqState->stateML.table + seqState->stateML.state, sizeof(ZSTD_seqSymbol)); + ZSTD_memcpy(ofDInfo, seqState->stateOffb.table + seqState->stateOffb.state, sizeof(ZSTD_seqSymbol)); +#else 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; +#endif seq.matchLength = mlDInfo->baseValue; seq.litLength = llDInfo->baseValue; { U32 const ofBase = ofDInfo->baseValue; @@ -1186,28 +1265,31 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) U32 const llnbBits = llDInfo->nbBits; U32 const mlnbBits = mlDInfo->nbBits; U32 const ofnbBits = ofDInfo->nbBits; + + assert(llBits <= MaxLLBits); + assert(mlBits <= MaxMLBits); + assert(ofBits <= MaxOff); /* * As gcc has better branch and block analyzers, sometimes it is only - * valuable to mark likelyness for clang, it gives around 3-4% of + * valuable to mark likeliness 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); + ZSTD_STATIC_ASSERT(STREAM_ACCUMULATOR_MIN_32 > LONG_OFFSETS_MAX_EXTRA_BITS_32); + ZSTD_STATIC_ASSERT(STREAM_ACCUMULATOR_MIN_32 - LONG_OFFSETS_MAX_EXTRA_BITS_32 >= MaxMLBits); if (MEM_32bits() && longOffsets && (ofBits >= STREAM_ACCUMULATOR_MIN_32)) { - U32 const extraBits = ofBits - MIN(ofBits, 32 - seqState->DStream.bitsConsumed); + /* Always read extra bits, this keeps the logic simple, + * avoids branches, and avoids accidentally reading 0 bits. + */ + U32 const extraBits = LONG_OFFSETS_MAX_EXTRA_BITS_32; 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 */ + offset += BIT_readBitsFast(&seqState->DStream, extraBits); } else { offset = ofBase + BIT_readBitsFast(&seqState->DStream, ofBits/*>0*/); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */ if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); @@ -1224,7 +1306,7 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) } 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 */ + temp -= !temp; /* 0 is not valid: input corrupted => force offset to -1 => corruption detected at execSequence */ if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1]; seqState->prevOffset[1] = seqState->prevOffset[0]; seqState->prevOffset[0] = offset = temp; @@ -1232,11 +1314,7 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) 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)) @@ -1246,11 +1324,7 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) /* 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()) @@ -1259,17 +1333,22 @@ ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets) 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 */ + if (!isLastSeq) { + /* don't update FSE state for last Sequence */ + 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 */ + BIT_reloadDStream(&seqState->DStream); + } } return seq; } -#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION -MEM_STATIC int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefixStart, BYTE const* oLitEnd) +#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE) +#if DEBUGLEVEL >= 1 +static int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefixStart, BYTE const* oLitEnd) { size_t const windowSize = dctx->fParams.windowSize; /* No dictionary used. */ @@ -1283,30 +1362,33 @@ MEM_STATIC int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefix /* Dictionary is active. */ return 1; } +#endif -MEM_STATIC void ZSTD_assertValidSequence( +static void ZSTD_assertValidSequence( ZSTD_DCtx const* dctx, BYTE const* op, BYTE const* oend, 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; - DEBUGLOG(6, "Checking sequence: litL=%u matchL=%u offset=%u", - (U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset); - assert(op <= oend); - assert((size_t)(oend - op) >= sequenceSize); - assert(sequenceSize <= ZSTD_BLOCKSIZE_MAX); - if (ZSTD_dictionaryIsActive(dctx, prefixStart, oLitEnd)) { - size_t const dictSize = (size_t)((char const*)dctx->dictContentEndForFuzzing - (char const*)dctx->dictContentBeginForFuzzing); - /* Offset must be within the dictionary. */ - assert(seq.offset <= (size_t)(oLitEnd - virtualStart)); - assert(seq.offset <= windowSize + dictSize); - } else { - /* Offset must be within our window. */ - assert(seq.offset <= windowSize); + if (dctx->isFrameDecompression) { + size_t const windowSize = dctx->fParams.windowSize; + size_t const sequenceSize = seq.litLength + seq.matchLength; + BYTE const* const oLitEnd = op + seq.litLength; + DEBUGLOG(6, "Checking sequence: litL=%u matchL=%u offset=%u", + (U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset); + assert(op <= oend); + assert((size_t)(oend - op) >= sequenceSize); + assert(sequenceSize <= ZSTD_blockSizeMax(dctx)); + if (ZSTD_dictionaryIsActive(dctx, prefixStart, oLitEnd)) { + size_t const dictSize = (size_t)((char const*)dctx->dictContentEndForFuzzing - (char const*)dctx->dictContentBeginForFuzzing); + /* Offset must be within the dictionary. */ + assert(seq.offset <= (size_t)(oLitEnd - virtualStart)); + assert(seq.offset <= windowSize + dictSize); + } else { + /* Offset must be within our window. */ + assert(seq.offset <= windowSize); + } } #else (void)dctx, (void)op, (void)oend, (void)seq, (void)prefixStart, (void)virtualStart; @@ -1322,23 +1404,21 @@ DONT_VECTORIZE ZSTD_decompressSequences_bodySplitLitBuffer( 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 ZSTD_longOffset_e isLongOffset) { const BYTE* ip = (const BYTE*)seqStart; const BYTE* const iend = ip + seqSize; BYTE* const ostart = (BYTE*)dst; - BYTE* const oend = ostart + maxDstSize; + BYTE* const oend = ZSTD_maybeNullPtrAdd(ostart, maxDstSize); BYTE* op = ostart; const BYTE* litPtr = dctx->litPtr; 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_bodySplitLitBuffer"); - (void)frame; + DEBUGLOG(5, "ZSTD_decompressSequences_bodySplitLitBuffer (%i seqs)", nbSeq); - /* Regen sequences */ + /* Literals are split between internal buffer & output buffer */ if (nbSeq) { seqState_t seqState; dctx->fseEntropy = 1; @@ -1357,8 +1437,7 @@ ZSTD_decompressSequences_bodySplitLitBuffer( ZSTD_DCtx* dctx, BIT_DStream_completed < BIT_DStream_overflow); /* decompress without overrunning litPtr begins */ - { - seq_t sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + { seq_t sequence = {0,0,0}; /* some static analyzer believe that @sequence is not initialized (it necessarily is, since for(;;) loop as at least one iteration) */ /* Align the decompression loop to 32 + 16 bytes. * * zstd compiled with gcc-9 on an Intel i9-9900k shows 10% decompression @@ -1420,27 +1499,26 @@ ZSTD_decompressSequences_bodySplitLitBuffer( ZSTD_DCtx* dctx, #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); + for ( ; nbSeq; nbSeq--) { + sequence = ZSTD_decodeSequence(&seqState, isLongOffset, nbSeq==1); + if (litPtr + sequence.litLength > dctx->litBufferEnd) break; + { 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); + assert(!ZSTD_isError(oneSeqSize)); + 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 (UNLIKELY(ZSTD_isError(oneSeqSize))) + return oneSeqSize; + DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize); + op += oneSeqSize; + } } + DEBUGLOG(6, "reached: (litPtr + sequence.litLength > dctx->litBufferEnd)"); /* 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) - { + DEBUGLOG(6, "There are %i sequences left, and %zu/%zu literals left in buffer", nbSeq, leftoverLit, sequence.litLength); + 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; @@ -1449,24 +1527,22 @@ ZSTD_decompressSequences_bodySplitLitBuffer( ZSTD_DCtx* dctx, 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); + { 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); + 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)); } + nbSeq--; } } - if (nbSeq > 0) /* there is remaining lit from extra buffer */ - { + if (nbSeq > 0) { + /* there is remaining lit from extra buffer */ #if defined(__x86_64__) __asm__(".p2align 6"); @@ -1485,35 +1561,34 @@ ZSTD_decompressSequences_bodySplitLitBuffer( ZSTD_DCtx* dctx, # endif #endif - for (; ; ) { - seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + for ( ; nbSeq ; nbSeq--) { + seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset, nbSeq==1); 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); + 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, ""); + DEBUGLOG(5, "bitStream : start=%p, ptr=%p, bitsConsumed=%u", seqState.DStream.start, seqState.DStream.ptr, seqState.DStream.bitsConsumed); + RETURN_ERROR_IF(!BIT_endOfDStream(&seqState.DStream), 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; + if (dctx->litBufferLocation == ZSTD_split) { + /* split hasn't been reached yet, first get dst then copy litExtraBuffer */ + size_t const lastLLSize = (size_t)(litBufferEnd - litPtr); + DEBUGLOG(6, "copy last literals from segment : %u", (U32)lastLLSize); RETURN_ERROR_IF(lastLLSize > (size_t)(oend - op), dstSize_tooSmall, ""); if (op != NULL) { ZSTD_memmove(op, litPtr, lastLLSize); @@ -1523,15 +1598,17 @@ ZSTD_decompressSequences_bodySplitLitBuffer( ZSTD_DCtx* dctx, litBufferEnd = dctx->litExtraBuffer + ZSTD_LITBUFFEREXTRASIZE; dctx->litBufferLocation = ZSTD_not_in_dst; } - { size_t const lastLLSize = litBufferEnd - litPtr; + /* copy last literals from internal buffer */ + { size_t const lastLLSize = (size_t)(litBufferEnd - litPtr); + DEBUGLOG(6, "copy last literals from internal buffer : %u", (U32)lastLLSize); RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, ""); if (op != NULL) { ZSTD_memcpy(op, litPtr, lastLLSize); op += lastLLSize; - } - } + } } - return op-ostart; + DEBUGLOG(6, "decoded block of size %u bytes", (U32)(op - ostart)); + return (size_t)(op - ostart); } FORCE_INLINE_TEMPLATE size_t @@ -1539,21 +1616,19 @@ 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 ZSTD_longOffset_e isLongOffset) { 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* const oend = dctx->litBufferLocation == ZSTD_not_in_dst ? ZSTD_maybeNullPtrAdd(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; + DEBUGLOG(5, "ZSTD_decompressSequences_body: nbSeq = %d", nbSeq); /* Regen sequences */ if (nbSeq) { @@ -1568,11 +1643,6 @@ ZSTD_decompressSequences_body(ZSTD_DCtx* dctx, 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(__x86_64__) __asm__(".p2align 6"); __asm__("nop"); @@ -1587,73 +1657,70 @@ ZSTD_decompressSequences_body(ZSTD_DCtx* dctx, # endif #endif - for ( ; ; ) { - seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + for ( ; nbSeq ; nbSeq--) { + seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset, nbSeq==1); 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); + 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_body: 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, ""); + assert(nbSeq == 0); + RETURN_ERROR_IF(!BIT_endOfDStream(&seqState.DStream), 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 */ - { size_t const lastLLSize = litEnd - litPtr; + { size_t const lastLLSize = (size_t)(litEnd - litPtr); + DEBUGLOG(6, "copy last literals : %u", (U32)lastLLSize); RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, ""); if (op != NULL) { ZSTD_memcpy(op, litPtr, lastLLSize); op += lastLLSize; - } - } + } } - return op-ostart; + DEBUGLOG(6, "decoded block of size %u bytes", (U32)(op - ostart)); + return (size_t)(op - ostart); } static size_t ZSTD_decompressSequences_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) + const ZSTD_longOffset_e isLongOffset) { - return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } 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) + const ZSTD_longOffset_e isLongOffset) { - return ZSTD_decompressSequences_bodySplitLitBuffer(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequences_bodySplitLitBuffer(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #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, +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 */ + /* 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 */ + const BYTE* const match = ZSTD_wrappedPtrSub(ZSTD_wrappedPtrAdd(matchBase, prefetchPos), sequence.offset); 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; @@ -1668,20 +1735,18 @@ ZSTD_decompressSequencesLong_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 ZSTD_longOffset_e isLongOffset) { const BYTE* ip = (const BYTE*)seqStart; const BYTE* const iend = ip + seqSize; BYTE* const ostart = (BYTE*)dst; - BYTE* const oend = dctx->litBufferLocation == ZSTD_in_dst ? dctx->litBuffer : ostart + maxDstSize; + BYTE* const oend = dctx->litBufferLocation == ZSTD_in_dst ? dctx->litBuffer : ZSTD_maybeNullPtrAdd(ostart, maxDstSize); BYTE* op = ostart; const BYTE* litPtr = dctx->litPtr; 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); - (void)frame; /* Regen sequences */ if (nbSeq) { @@ -1706,20 +1771,17 @@ ZSTD_decompressSequencesLong_body( ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr); /* prepare in advance */ - for (seqNb=0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && (seqNb<seqAdvance); seqNb++) { - seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset); + for (seqNb=0; seqNb<seqAdvance; seqNb++) { + seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset, seqNb == nbSeq-1); prefetchPos = ZSTD_prefetchMatch(prefetchPos, sequence, prefixStart, dictEnd); sequences[seqNb] = sequence; } - RETURN_ERROR_IF(seqNb<seqAdvance, corruption_detected, ""); /* 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; + for (; seqNb < nbSeq; seqNb++) { + seq_t sequence = ZSTD_decodeSequence(&seqState, isLongOffset, seqNb == nbSeq-1); - if (dctx->litBufferLocation == ZSTD_split && litPtr + sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK].litLength > dctx->litBufferEnd) - { + 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) @@ -1732,26 +1794,26 @@ ZSTD_decompressSequencesLong_body( 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); + { size_t const 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)); + ZSTD_assertValidSequence(dctx, op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], prefixStart, dictStart); #endif - if (ZSTD_isError(oneSeqSize)) return oneSeqSize; + if (ZSTD_isError(oneSeqSize)) return oneSeqSize; - prefetchPos = ZSTD_prefetchMatch(prefetchPos, sequence, prefixStart, dictEnd); - sequences[seqNb & STORED_SEQS_MASK] = sequence; - op += 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 ? + size_t const 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); + ZSTD_assertValidSequence(dctx, op, oend, sequences[(seqNb - ADVANCED_SEQS) & STORED_SEQS_MASK], prefixStart, dictStart); #endif if (ZSTD_isError(oneSeqSize)) return oneSeqSize; @@ -1760,17 +1822,15 @@ ZSTD_decompressSequencesLong_body( op += oneSeqSize; } } - RETURN_ERROR_IF(seqNb<nbSeq, corruption_detected, ""); + RETURN_ERROR_IF(!BIT_endOfDStream(&seqState.DStream), corruption_detected, ""); /* finish queue */ seqNb -= seqAdvance; for ( ; seqNb<nbSeq ; seqNb++) { seq_t *sequence = &(sequences[seqNb&STORED_SEQS_MASK]); - if (dctx->litBufferLocation == ZSTD_split && litPtr + sequence->litLength > dctx->litBufferEnd) - { + if (dctx->litBufferLocation == ZSTD_split && litPtr + sequence->litLength > dctx->litBufferEnd) { const size_t leftoverLit = dctx->litBufferEnd - litPtr; - if (leftoverLit) - { + 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; @@ -1779,11 +1839,10 @@ ZSTD_decompressSequencesLong_body( 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); + { 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); + ZSTD_assertValidSequence(dctx, op, oend, sequences[seqNb&STORED_SEQS_MASK], prefixStart, dictStart); #endif if (ZSTD_isError(oneSeqSize)) return oneSeqSize; op += oneSeqSize; @@ -1796,7 +1855,7 @@ ZSTD_decompressSequencesLong_body( 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); + ZSTD_assertValidSequence(dctx, op, oend, sequences[seqNb&STORED_SEQS_MASK], prefixStart, dictStart); #endif if (ZSTD_isError(oneSeqSize)) return oneSeqSize; op += oneSeqSize; @@ -1808,8 +1867,7 @@ ZSTD_decompressSequencesLong_body( } /* last literal segment */ - if (dctx->litBufferLocation == ZSTD_split) /* first deplete literal buffer in dst, then copy litExtraBuffer */ - { + 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) { @@ -1827,17 +1885,16 @@ ZSTD_decompressSequencesLong_body( } } - return op-ostart; + return (size_t)(op - ostart); } static size_t ZSTD_decompressSequencesLong_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) + const ZSTD_longOffset_e isLongOffset) { - return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */ @@ -1851,20 +1908,18 @@ DONT_VECTORIZE ZSTD_decompressSequences_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) + const ZSTD_longOffset_e isLongOffset) { - return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } 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) + const ZSTD_longOffset_e isLongOffset) { - return ZSTD_decompressSequences_bodySplitLitBuffer(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequences_bodySplitLitBuffer(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */ @@ -1873,50 +1928,40 @@ 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, - const ZSTD_longOffset_e isLongOffset, - const int frame) + const ZSTD_longOffset_e isLongOffset) { - return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */ #endif /* DYNAMIC_BMI2 */ -typedef size_t (*ZSTD_decompressSequences_t)( - ZSTD_DCtx* dctx, - void* dst, size_t maxDstSize, - const void* seqStart, size_t seqSize, int nbSeq, - const ZSTD_longOffset_e isLongOffset, - const int frame); - #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG static size_t ZSTD_decompressSequences(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 ZSTD_longOffset_e isLongOffset) { DEBUGLOG(5, "ZSTD_decompressSequences"); #if DYNAMIC_BMI2 if (ZSTD_DCtx_get_bmi2(dctx)) { - return ZSTD_decompressSequences_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequences_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #endif - return ZSTD_decompressSequences_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequences_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } 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) + const ZSTD_longOffset_e isLongOffset) { 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); + return ZSTD_decompressSequencesSplitLitBuffer_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #endif - return ZSTD_decompressSequencesSplitLitBuffer_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequencesSplitLitBuffer_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */ @@ -1931,69 +1976,114 @@ static size_t ZSTD_decompressSequencesLong(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 ZSTD_longOffset_e isLongOffset) { DEBUGLOG(5, "ZSTD_decompressSequencesLong"); #if DYNAMIC_BMI2 if (ZSTD_DCtx_get_bmi2(dctx)) { - return ZSTD_decompressSequencesLong_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequencesLong_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #endif - return ZSTD_decompressSequencesLong_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequencesLong_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset); } #endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */ +/* + * @returns The total size of the history referenceable by zstd, including + * both the prefix and the extDict. At @p op any offset larger than this + * is invalid. + */ +static size_t ZSTD_totalHistorySize(BYTE* op, BYTE const* virtualStart) +{ + return (size_t)(op - virtualStart); +} + +typedef struct { + unsigned longOffsetShare; + unsigned maxNbAdditionalBits; +} ZSTD_OffsetInfo; -#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \ - !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG) -/* ZSTD_getLongOffsetsShare() : +/* ZSTD_getOffsetInfo() : * condition : offTable must be valid * @return : "share" of long offsets (arbitrarily defined as > (1<<23)) - * compared to maximum possible of (1<<OffFSELog) */ -static unsigned -ZSTD_getLongOffsetsShare(const ZSTD_seqSymbol* offTable) + * compared to maximum possible of (1<<OffFSELog), + * as well as the maximum number additional bits required. + */ +static ZSTD_OffsetInfo +ZSTD_getOffsetInfo(const ZSTD_seqSymbol* offTable, int nbSeq) { - const void* ptr = offTable; - U32 const tableLog = ((const ZSTD_seqSymbol_header*)ptr)[0].tableLog; - const ZSTD_seqSymbol* table = offTable + 1; - U32 const max = 1 << tableLog; - U32 u, total = 0; - DEBUGLOG(5, "ZSTD_getLongOffsetsShare: (tableLog=%u)", tableLog); - - assert(max <= (1 << OffFSELog)); /* max not too large */ - for (u=0; u<max; u++) { - if (table[u].nbAdditionalBits > 22) total += 1; + ZSTD_OffsetInfo info = {0, 0}; + /* If nbSeq == 0, then the offTable is uninitialized, but we have + * no sequences, so both values should be 0. + */ + if (nbSeq != 0) { + const void* ptr = offTable; + U32 const tableLog = ((const ZSTD_seqSymbol_header*)ptr)[0].tableLog; + const ZSTD_seqSymbol* table = offTable + 1; + U32 const max = 1 << tableLog; + U32 u; + DEBUGLOG(5, "ZSTD_getLongOffsetsShare: (tableLog=%u)", tableLog); + + assert(max <= (1 << OffFSELog)); /* max not too large */ + for (u=0; u<max; u++) { + info.maxNbAdditionalBits = MAX(info.maxNbAdditionalBits, table[u].nbAdditionalBits); + if (table[u].nbAdditionalBits > 22) info.longOffsetShare += 1; + } + + assert(tableLog <= OffFSELog); + info.longOffsetShare <<= (OffFSELog - tableLog); /* scale to OffFSELog */ } - assert(tableLog <= OffFSELog); - total <<= (OffFSELog - tableLog); /* scale to OffFSELog */ + return info; +} - return total; +/* + * @returns The maximum offset we can decode in one read of our bitstream, without + * reloading more bits in the middle of the offset bits read. Any offsets larger + * than this must use the long offset decoder. + */ +static size_t ZSTD_maxShortOffset(void) +{ + if (MEM_64bits()) { + /* We can decode any offset without reloading bits. + * This might change if the max window size grows. + */ + ZSTD_STATIC_ASSERT(ZSTD_WINDOWLOG_MAX <= 31); + return (size_t)-1; + } else { + /* The maximum offBase is (1 << (STREAM_ACCUMULATOR_MIN + 1)) - 1. + * This offBase would require STREAM_ACCUMULATOR_MIN extra bits. + * Then we have to subtract ZSTD_REP_NUM to get the maximum possible offset. + */ + size_t const maxOffbase = ((size_t)1 << (STREAM_ACCUMULATOR_MIN + 1)) - 1; + size_t const maxOffset = maxOffbase - ZSTD_REP_NUM; + assert(ZSTD_highbit32((U32)maxOffbase) == STREAM_ACCUMULATOR_MIN); + return maxOffset; + } } -#endif size_t ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, - const void* src, size_t srcSize, const int frame, const streaming_operation streaming) + const void* src, size_t srcSize, const streaming_operation streaming) { /* blockType == blockCompressed */ const BYTE* ip = (const BYTE*)src; - /* isLongOffset must be true if there are long offsets. - * Offsets are long if they are larger than 2^STREAM_ACCUMULATOR_MIN. - * We don't expect that to be the case in 64-bit mode. - * In block mode, window size is not known, so we have to be conservative. - * (note: but it could be evaluated from current-lowLimit) - */ - ZSTD_longOffset_e const isLongOffset = (ZSTD_longOffset_e)(MEM_32bits() && (!frame || (dctx->fParams.windowSize > (1ULL << STREAM_ACCUMULATOR_MIN)))); - DEBUGLOG(5, "ZSTD_decompressBlock_internal (size : %u)", (U32)srcSize); - - RETURN_ERROR_IF(srcSize >= ZSTD_BLOCKSIZE_MAX, srcSize_wrong, ""); + DEBUGLOG(5, "ZSTD_decompressBlock_internal (cSize : %u)", (unsigned)srcSize); + + /* Note : the wording of the specification + * allows compressed block to be sized exactly ZSTD_blockSizeMax(dctx). + * This generally does not happen, as it makes little sense, + * since an uncompressed block would feature same size and have no decompression cost. + * Also, note that decoder from reference libzstd before < v1.5.4 + * would consider this edge case as an error. + * As a consequence, avoid generating compressed blocks of size ZSTD_blockSizeMax(dctx) + * for broader compatibility with the deployed ecosystem of zstd decoders */ + RETURN_ERROR_IF(srcSize > ZSTD_blockSizeMax(dctx), srcSize_wrong, ""); /* Decode literals section */ { size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize, dst, dstCapacity, streaming); - DEBUGLOG(5, "ZSTD_decodeLiteralsBlock : %u", (U32)litCSize); + DEBUGLOG(5, "ZSTD_decodeLiteralsBlock : cSize=%u, nbLiterals=%zu", (U32)litCSize, dctx->litSize); if (ZSTD_isError(litCSize)) return litCSize; ip += litCSize; srcSize -= litCSize; @@ -2001,6 +2091,23 @@ ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx, /* Build Decoding Tables */ { + /* Compute the maximum block size, which must also work when !frame and fParams are unset. + * Additionally, take the min with dstCapacity to ensure that the totalHistorySize fits in a size_t. + */ + size_t const blockSizeMax = MIN(dstCapacity, ZSTD_blockSizeMax(dctx)); + size_t const totalHistorySize = ZSTD_totalHistorySize(ZSTD_maybeNullPtrAdd((BYTE*)dst, blockSizeMax), (BYTE const*)dctx->virtualStart); + /* isLongOffset must be true if there are long offsets. + * Offsets are long if they are larger than ZSTD_maxShortOffset(). + * We don't expect that to be the case in 64-bit mode. + * + * We check here to see if our history is large enough to allow long offsets. + * If it isn't, then we can't possible have (valid) long offsets. If the offset + * is invalid, then it is okay to read it incorrectly. + * + * If isLongOffsets is true, then we will later check our decoding table to see + * if it is even possible to generate long offsets. + */ + ZSTD_longOffset_e isLongOffset = (ZSTD_longOffset_e)(MEM_32bits() && (totalHistorySize > ZSTD_maxShortOffset())); /* These macros control at build-time which decompressor implementation * we use. If neither is defined, we do some inspection and dispatch at * runtime. @@ -2008,6 +2115,11 @@ ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx, #if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \ !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG) int usePrefetchDecoder = dctx->ddictIsCold; +#else + /* Set to 1 to avoid computing offset info if we don't need to. + * Otherwise this value is ignored. + */ + int usePrefetchDecoder = 1; #endif int nbSeq; size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, srcSize); @@ -2015,40 +2127,55 @@ ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx, ip += seqHSize; srcSize -= seqHSize; - RETURN_ERROR_IF(dst == NULL && nbSeq > 0, dstSize_tooSmall, "NULL not handled"); + RETURN_ERROR_IF((dst == NULL || dstCapacity == 0) && nbSeq > 0, dstSize_tooSmall, "NULL not handled"); + RETURN_ERROR_IF(MEM_64bits() && sizeof(size_t) == sizeof(void*) && (size_t)(-1) - (size_t)dst < (size_t)(1 << 20), dstSize_tooSmall, + "invalid dst"); -#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \ - !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG) - if ( !usePrefetchDecoder - && (!frame || (dctx->fParams.windowSize > (1<<24))) - && (nbSeq>ADVANCED_SEQS) ) { /* could probably use a larger nbSeq limit */ - U32 const shareLongOffsets = ZSTD_getLongOffsetsShare(dctx->OFTptr); - U32 const minShare = MEM_64bits() ? 7 : 20; /* heuristic values, correspond to 2.73% and 7.81% */ - usePrefetchDecoder = (shareLongOffsets >= minShare); + /* If we could potentially have long offsets, or we might want to use the prefetch decoder, + * compute information about the share of long offsets, and the maximum nbAdditionalBits. + * NOTE: could probably use a larger nbSeq limit + */ + if (isLongOffset || (!usePrefetchDecoder && (totalHistorySize > (1u << 24)) && (nbSeq > 8))) { + ZSTD_OffsetInfo const info = ZSTD_getOffsetInfo(dctx->OFTptr, nbSeq); + if (isLongOffset && info.maxNbAdditionalBits <= STREAM_ACCUMULATOR_MIN) { + /* If isLongOffset, but the maximum number of additional bits that we see in our table is small + * enough, then we know it is impossible to have too long an offset in this block, so we can + * use the regular offset decoder. + */ + isLongOffset = ZSTD_lo_isRegularOffset; + } + if (!usePrefetchDecoder) { + U32 const minShare = MEM_64bits() ? 7 : 20; /* heuristic values, correspond to 2.73% and 7.81% */ + usePrefetchDecoder = (info.longOffsetShare >= minShare); + } } -#endif dctx->ddictIsCold = 0; #if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \ !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG) - if (usePrefetchDecoder) + if (usePrefetchDecoder) { +#else + (void)usePrefetchDecoder; + { #endif #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT - return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset); #endif + } #ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG /* else */ if (dctx->litBufferLocation == ZSTD_split) - return ZSTD_decompressSequencesSplitLitBuffer(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequencesSplitLitBuffer(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset); else - return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame); + return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset); #endif } } +ZSTD_ALLOW_POINTER_OVERFLOW_ATTR void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize) { if (dst != dctx->previousDstEnd && dstSize > 0) { /* not contiguous */ @@ -2060,13 +2187,24 @@ void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize) } -size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, - void* dst, size_t dstCapacity, - const void* src, size_t srcSize) +size_t ZSTD_decompressBlock_deprecated(ZSTD_DCtx* dctx, + void* dst, size_t dstCapacity, + const void* src, size_t srcSize) { size_t dSize; + dctx->isFrameDecompression = 0; ZSTD_checkContinuity(dctx, dst, dstCapacity); - dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 0, not_streaming); + dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, not_streaming); + FORWARD_IF_ERROR(dSize, ""); dctx->previousDstEnd = (char*)dst + dSize; return dSize; } + + +/* NOTE: Must just wrap ZSTD_decompressBlock_deprecated() */ +size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx, + void* dst, size_t dstCapacity, + const void* src, size_t srcSize) +{ + return ZSTD_decompressBlock_deprecated(dctx, dst, dstCapacity, src, srcSize); +} |