| /* |
| * Copyright (c) Meta Platforms, Inc. and affiliates. |
| * All rights reserved. |
| * |
| * This source code is licensed under both the BSD-style license (found in the |
| * LICENSE file in the root directory of this source tree) and the GPLv2 (found |
| * in the COPYING file in the root directory of this source tree). |
| * You may select, at your option, one of the above-listed licenses. |
| */ |
| |
| /*-************************************* |
| * Dependencies |
| ***************************************/ |
| #include "zstd_compress_superblock.h" |
| |
| #include "../common/zstd_internal.h" /* ZSTD_getSequenceLength */ |
| #include "hist.h" /* HIST_countFast_wksp */ |
| #include "zstd_compress_internal.h" /* ZSTD_[huf|fse|entropy]CTablesMetadata_t */ |
| #include "zstd_compress_sequences.h" |
| #include "zstd_compress_literals.h" |
| |
| /** ZSTD_compressSubBlock_literal() : |
| * Compresses literals section for a sub-block. |
| * When we have to write the Huffman table we will sometimes choose a header |
| * size larger than necessary. This is because we have to pick the header size |
| * before we know the table size + compressed size, so we have a bound on the |
| * table size. If we guessed incorrectly, we fall back to uncompressed literals. |
| * |
| * We write the header when writeEntropy=1 and set entropyWritten=1 when we succeeded |
| * in writing the header, otherwise it is set to 0. |
| * |
| * hufMetadata->hType has literals block type info. |
| * If it is set_basic, all sub-blocks literals section will be Raw_Literals_Block. |
| * If it is set_rle, all sub-blocks literals section will be RLE_Literals_Block. |
| * If it is set_compressed, first sub-block's literals section will be Compressed_Literals_Block |
| * If it is set_compressed, first sub-block's literals section will be Treeless_Literals_Block |
| * and the following sub-blocks' literals sections will be Treeless_Literals_Block. |
| * @return : compressed size of literals section of a sub-block |
| * Or 0 if unable to compress. |
| * Or error code */ |
| static size_t |
| ZSTD_compressSubBlock_literal(const HUF_CElt* hufTable, |
| const ZSTD_hufCTablesMetadata_t* hufMetadata, |
| const BYTE* literals, size_t litSize, |
| void* dst, size_t dstSize, |
| const int bmi2, int writeEntropy, int* entropyWritten) |
| { |
| size_t const header = writeEntropy ? 200 : 0; |
| size_t const lhSize = 3 + (litSize >= (1 KB - header)) + (litSize >= (16 KB - header)); |
| BYTE* const ostart = (BYTE*)dst; |
| BYTE* const oend = ostart + dstSize; |
| BYTE* op = ostart + lhSize; |
| U32 const singleStream = lhSize == 3; |
| SymbolEncodingType_e hType = writeEntropy ? hufMetadata->hType : set_repeat; |
| size_t cLitSize = 0; |
| |
| DEBUGLOG(5, "ZSTD_compressSubBlock_literal (litSize=%zu, lhSize=%zu, writeEntropy=%d)", litSize, lhSize, writeEntropy); |
| |
| *entropyWritten = 0; |
| if (litSize == 0 || hufMetadata->hType == set_basic) { |
| DEBUGLOG(5, "ZSTD_compressSubBlock_literal using raw literal"); |
| return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize); |
| } else if (hufMetadata->hType == set_rle) { |
| DEBUGLOG(5, "ZSTD_compressSubBlock_literal using rle literal"); |
| return ZSTD_compressRleLiteralsBlock(dst, dstSize, literals, litSize); |
| } |
| |
| assert(litSize > 0); |
| assert(hufMetadata->hType == set_compressed || hufMetadata->hType == set_repeat); |
| |
| if (writeEntropy && hufMetadata->hType == set_compressed) { |
| ZSTD_memcpy(op, hufMetadata->hufDesBuffer, hufMetadata->hufDesSize); |
| op += hufMetadata->hufDesSize; |
| cLitSize += hufMetadata->hufDesSize; |
| DEBUGLOG(5, "ZSTD_compressSubBlock_literal (hSize=%zu)", hufMetadata->hufDesSize); |
| } |
| |
| { int const flags = bmi2 ? HUF_flags_bmi2 : 0; |
| const size_t cSize = singleStream ? HUF_compress1X_usingCTable(op, (size_t)(oend-op), literals, litSize, hufTable, flags) |
| : HUF_compress4X_usingCTable(op, (size_t)(oend-op), literals, litSize, hufTable, flags); |
| op += cSize; |
| cLitSize += cSize; |
| if (cSize == 0 || ERR_isError(cSize)) { |
| DEBUGLOG(5, "Failed to write entropy tables %s", ZSTD_getErrorName(cSize)); |
| return 0; |
| } |
| /* If we expand and we aren't writing a header then emit uncompressed */ |
| if (!writeEntropy && cLitSize >= litSize) { |
| DEBUGLOG(5, "ZSTD_compressSubBlock_literal using raw literal because uncompressible"); |
| return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize); |
| } |
| /* If we are writing headers then allow expansion that doesn't change our header size. */ |
| if (lhSize < (size_t)(3 + (cLitSize >= 1 KB) + (cLitSize >= 16 KB))) { |
| assert(cLitSize > litSize); |
| DEBUGLOG(5, "Literals expanded beyond allowed header size"); |
| return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize); |
| } |
| DEBUGLOG(5, "ZSTD_compressSubBlock_literal (cSize=%zu)", cSize); |
| } |
| |
| /* Build header */ |
| switch(lhSize) |
| { |
| case 3: /* 2 - 2 - 10 - 10 */ |
| { U32 const lhc = hType + ((U32)(!singleStream) << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<14); |
| MEM_writeLE24(ostart, lhc); |
| break; |
| } |
| case 4: /* 2 - 2 - 14 - 14 */ |
| { U32 const lhc = hType + (2 << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<18); |
| MEM_writeLE32(ostart, lhc); |
| break; |
| } |
| case 5: /* 2 - 2 - 18 - 18 */ |
| { U32 const lhc = hType + (3 << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<22); |
| MEM_writeLE32(ostart, lhc); |
| ostart[4] = (BYTE)(cLitSize >> 10); |
| break; |
| } |
| default: /* not possible : lhSize is {3,4,5} */ |
| assert(0); |
| } |
| *entropyWritten = 1; |
| DEBUGLOG(5, "Compressed literals: %u -> %u", (U32)litSize, (U32)(op-ostart)); |
| return (size_t)(op-ostart); |
| } |
| |
| static size_t |
| ZSTD_seqDecompressedSize(SeqStore_t const* seqStore, |
| const SeqDef* sequences, size_t nbSeqs, |
| size_t litSize, int lastSubBlock) |
| { |
| size_t matchLengthSum = 0; |
| size_t litLengthSum = 0; |
| size_t n; |
| for (n=0; n<nbSeqs; n++) { |
| const ZSTD_SequenceLength seqLen = ZSTD_getSequenceLength(seqStore, sequences+n); |
| litLengthSum += seqLen.litLength; |
| matchLengthSum += seqLen.matchLength; |
| } |
| DEBUGLOG(5, "ZSTD_seqDecompressedSize: %u sequences from %p: %u literals + %u matchlength", |
| (unsigned)nbSeqs, (const void*)sequences, |
| (unsigned)litLengthSum, (unsigned)matchLengthSum); |
| if (!lastSubBlock) |
| assert(litLengthSum == litSize); |
| else |
| assert(litLengthSum <= litSize); |
| (void)litLengthSum; |
| return matchLengthSum + litSize; |
| } |
| |
| /** ZSTD_compressSubBlock_sequences() : |
| * Compresses sequences section for a sub-block. |
| * fseMetadata->llType, fseMetadata->ofType, and fseMetadata->mlType have |
| * symbol compression modes for the super-block. |
| * The first successfully compressed block will have these in its header. |
| * We set entropyWritten=1 when we succeed in compressing the sequences. |
| * The following sub-blocks will always have repeat mode. |
| * @return : compressed size of sequences section of a sub-block |
| * Or 0 if it is unable to compress |
| * Or error code. */ |
| static size_t |
| ZSTD_compressSubBlock_sequences(const ZSTD_fseCTables_t* fseTables, |
| const ZSTD_fseCTablesMetadata_t* fseMetadata, |
| const SeqDef* sequences, size_t nbSeq, |
| const BYTE* llCode, const BYTE* mlCode, const BYTE* ofCode, |
| const ZSTD_CCtx_params* cctxParams, |
| void* dst, size_t dstCapacity, |
| const int bmi2, int writeEntropy, int* entropyWritten) |
| { |
| const int longOffsets = cctxParams->cParams.windowLog > STREAM_ACCUMULATOR_MIN; |
| BYTE* const ostart = (BYTE*)dst; |
| BYTE* const oend = ostart + dstCapacity; |
| BYTE* op = ostart; |
| BYTE* seqHead; |
| |
| DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (nbSeq=%zu, writeEntropy=%d, longOffsets=%d)", nbSeq, writeEntropy, longOffsets); |
| |
| *entropyWritten = 0; |
| /* Sequences Header */ |
| RETURN_ERROR_IF((oend-op) < 3 /*max nbSeq Size*/ + 1 /*seqHead*/, |
| dstSize_tooSmall, ""); |
| if (nbSeq < 128) |
| *op++ = (BYTE)nbSeq; |
| else if (nbSeq < LONGNBSEQ) |
| op[0] = (BYTE)((nbSeq>>8) + 0x80), op[1] = (BYTE)nbSeq, op+=2; |
| else |
| op[0]=0xFF, MEM_writeLE16(op+1, (U16)(nbSeq - LONGNBSEQ)), op+=3; |
| if (nbSeq==0) { |
| return (size_t)(op - ostart); |
| } |
| |
| /* seqHead : flags for FSE encoding type */ |
| seqHead = op++; |
| |
| DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (seqHeadSize=%u)", (unsigned)(op-ostart)); |
| |
| if (writeEntropy) { |
| const U32 LLtype = fseMetadata->llType; |
| const U32 Offtype = fseMetadata->ofType; |
| const U32 MLtype = fseMetadata->mlType; |
| DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (fseTablesSize=%zu)", fseMetadata->fseTablesSize); |
| *seqHead = (BYTE)((LLtype<<6) + (Offtype<<4) + (MLtype<<2)); |
| ZSTD_memcpy(op, fseMetadata->fseTablesBuffer, fseMetadata->fseTablesSize); |
| op += fseMetadata->fseTablesSize; |
| } else { |
| const U32 repeat = set_repeat; |
| *seqHead = (BYTE)((repeat<<6) + (repeat<<4) + (repeat<<2)); |
| } |
| |
| { size_t const bitstreamSize = ZSTD_encodeSequences( |
| op, (size_t)(oend - op), |
| fseTables->matchlengthCTable, mlCode, |
| fseTables->offcodeCTable, ofCode, |
| fseTables->litlengthCTable, llCode, |
| sequences, nbSeq, |
| longOffsets, bmi2); |
| FORWARD_IF_ERROR(bitstreamSize, "ZSTD_encodeSequences failed"); |
| op += bitstreamSize; |
| /* zstd versions <= 1.3.4 mistakenly report corruption when |
| * FSE_readNCount() receives a buffer < 4 bytes. |
| * Fixed by https://github.com/facebook/zstd/pull/1146. |
| * This can happen when the last set_compressed table present is 2 |
| * bytes and the bitstream is only one byte. |
| * In this exceedingly rare case, we will simply emit an uncompressed |
| * block, since it isn't worth optimizing. |
| */ |
| #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION |
| if (writeEntropy && fseMetadata->lastCountSize && fseMetadata->lastCountSize + bitstreamSize < 4) { |
| /* NCountSize >= 2 && bitstreamSize > 0 ==> lastCountSize == 3 */ |
| assert(fseMetadata->lastCountSize + bitstreamSize == 3); |
| DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.3.4 by " |
| "emitting an uncompressed block."); |
| return 0; |
| } |
| #endif |
| DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (bitstreamSize=%zu)", bitstreamSize); |
| } |
| |
| /* zstd versions <= 1.4.0 mistakenly report error when |
| * sequences section body size is less than 3 bytes. |
| * Fixed by https://github.com/facebook/zstd/pull/1664. |
| * This can happen when the previous sequences section block is compressed |
| * with rle mode and the current block's sequences section is compressed |
| * with repeat mode where sequences section body size can be 1 byte. |
| */ |
| #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION |
| if (op-seqHead < 4) { |
| DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.4.0 by emitting " |
| "an uncompressed block when sequences are < 4 bytes"); |
| return 0; |
| } |
| #endif |
| |
| *entropyWritten = 1; |
| return (size_t)(op - ostart); |
| } |
| |
| /** ZSTD_compressSubBlock() : |
| * Compresses a single sub-block. |
| * @return : compressed size of the sub-block |
| * Or 0 if it failed to compress. */ |
| static size_t ZSTD_compressSubBlock(const ZSTD_entropyCTables_t* entropy, |
| const ZSTD_entropyCTablesMetadata_t* entropyMetadata, |
| const SeqDef* sequences, size_t nbSeq, |
| const BYTE* literals, size_t litSize, |
| const BYTE* llCode, const BYTE* mlCode, const BYTE* ofCode, |
| const ZSTD_CCtx_params* cctxParams, |
| void* dst, size_t dstCapacity, |
| const int bmi2, |
| int writeLitEntropy, int writeSeqEntropy, |
| int* litEntropyWritten, int* seqEntropyWritten, |
| U32 lastBlock) |
| { |
| BYTE* const ostart = (BYTE*)dst; |
| BYTE* const oend = ostart + dstCapacity; |
| BYTE* op = ostart + ZSTD_blockHeaderSize; |
| DEBUGLOG(5, "ZSTD_compressSubBlock (litSize=%zu, nbSeq=%zu, writeLitEntropy=%d, writeSeqEntropy=%d, lastBlock=%d)", |
| litSize, nbSeq, writeLitEntropy, writeSeqEntropy, lastBlock); |
| { size_t cLitSize = ZSTD_compressSubBlock_literal((const HUF_CElt*)entropy->huf.CTable, |
| &entropyMetadata->hufMetadata, literals, litSize, |
| op, (size_t)(oend-op), |
| bmi2, writeLitEntropy, litEntropyWritten); |
| FORWARD_IF_ERROR(cLitSize, "ZSTD_compressSubBlock_literal failed"); |
| if (cLitSize == 0) return 0; |
| op += cLitSize; |
| } |
| { size_t cSeqSize = ZSTD_compressSubBlock_sequences(&entropy->fse, |
| &entropyMetadata->fseMetadata, |
| sequences, nbSeq, |
| llCode, mlCode, ofCode, |
| cctxParams, |
| op, (size_t)(oend-op), |
| bmi2, writeSeqEntropy, seqEntropyWritten); |
| FORWARD_IF_ERROR(cSeqSize, "ZSTD_compressSubBlock_sequences failed"); |
| if (cSeqSize == 0) return 0; |
| op += cSeqSize; |
| } |
| /* Write block header */ |
| { size_t cSize = (size_t)(op-ostart) - ZSTD_blockHeaderSize; |
| U32 const cBlockHeader24 = lastBlock + (((U32)bt_compressed)<<1) + (U32)(cSize << 3); |
| MEM_writeLE24(ostart, cBlockHeader24); |
| } |
| return (size_t)(op-ostart); |
| } |
| |
| static size_t ZSTD_estimateSubBlockSize_literal(const BYTE* literals, size_t litSize, |
| const ZSTD_hufCTables_t* huf, |
| const ZSTD_hufCTablesMetadata_t* hufMetadata, |
| void* workspace, size_t wkspSize, |
| int writeEntropy) |
| { |
| unsigned* const countWksp = (unsigned*)workspace; |
| unsigned maxSymbolValue = 255; |
| size_t literalSectionHeaderSize = 3; /* Use hard coded size of 3 bytes */ |
| |
| if (hufMetadata->hType == set_basic) return litSize; |
| else if (hufMetadata->hType == set_rle) return 1; |
| else if (hufMetadata->hType == set_compressed || hufMetadata->hType == set_repeat) { |
| size_t const largest = HIST_count_wksp (countWksp, &maxSymbolValue, (const BYTE*)literals, litSize, workspace, wkspSize); |
| if (ZSTD_isError(largest)) return litSize; |
| { size_t cLitSizeEstimate = HUF_estimateCompressedSize((const HUF_CElt*)huf->CTable, countWksp, maxSymbolValue); |
| if (writeEntropy) cLitSizeEstimate += hufMetadata->hufDesSize; |
| return cLitSizeEstimate + literalSectionHeaderSize; |
| } } |
| assert(0); /* impossible */ |
| return 0; |
| } |
| |
| static size_t ZSTD_estimateSubBlockSize_symbolType(SymbolEncodingType_e type, |
| const BYTE* codeTable, unsigned maxCode, |
| size_t nbSeq, const FSE_CTable* fseCTable, |
| const U8* additionalBits, |
| short const* defaultNorm, U32 defaultNormLog, U32 defaultMax, |
| void* workspace, size_t wkspSize) |
| { |
| unsigned* const countWksp = (unsigned*)workspace; |
| const BYTE* ctp = codeTable; |
| const BYTE* const ctStart = ctp; |
| const BYTE* const ctEnd = ctStart + nbSeq; |
| size_t cSymbolTypeSizeEstimateInBits = 0; |
| unsigned max = maxCode; |
| |
| HIST_countFast_wksp(countWksp, &max, codeTable, nbSeq, workspace, wkspSize); /* can't fail */ |
| if (type == set_basic) { |
| /* We selected this encoding type, so it must be valid. */ |
| assert(max <= defaultMax); |
| cSymbolTypeSizeEstimateInBits = max <= defaultMax |
| ? ZSTD_crossEntropyCost(defaultNorm, defaultNormLog, countWksp, max) |
| : ERROR(GENERIC); |
| } else if (type == set_rle) { |
| cSymbolTypeSizeEstimateInBits = 0; |
| } else if (type == set_compressed || type == set_repeat) { |
| cSymbolTypeSizeEstimateInBits = ZSTD_fseBitCost(fseCTable, countWksp, max); |
| } |
| if (ZSTD_isError(cSymbolTypeSizeEstimateInBits)) return nbSeq * 10; |
| while (ctp < ctEnd) { |
| if (additionalBits) cSymbolTypeSizeEstimateInBits += additionalBits[*ctp]; |
| else cSymbolTypeSizeEstimateInBits += *ctp; /* for offset, offset code is also the number of additional bits */ |
| ctp++; |
| } |
| return cSymbolTypeSizeEstimateInBits / 8; |
| } |
| |
| static size_t ZSTD_estimateSubBlockSize_sequences(const BYTE* ofCodeTable, |
| const BYTE* llCodeTable, |
| const BYTE* mlCodeTable, |
| size_t nbSeq, |
| const ZSTD_fseCTables_t* fseTables, |
| const ZSTD_fseCTablesMetadata_t* fseMetadata, |
| void* workspace, size_t wkspSize, |
| int writeEntropy) |
| { |
| size_t const sequencesSectionHeaderSize = 3; /* Use hard coded size of 3 bytes */ |
| size_t cSeqSizeEstimate = 0; |
| if (nbSeq == 0) return sequencesSectionHeaderSize; |
| cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->ofType, ofCodeTable, MaxOff, |
| nbSeq, fseTables->offcodeCTable, NULL, |
| OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff, |
| workspace, wkspSize); |
| cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->llType, llCodeTable, MaxLL, |
| nbSeq, fseTables->litlengthCTable, LL_bits, |
| LL_defaultNorm, LL_defaultNormLog, MaxLL, |
| workspace, wkspSize); |
| cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->mlType, mlCodeTable, MaxML, |
| nbSeq, fseTables->matchlengthCTable, ML_bits, |
| ML_defaultNorm, ML_defaultNormLog, MaxML, |
| workspace, wkspSize); |
| if (writeEntropy) cSeqSizeEstimate += fseMetadata->fseTablesSize; |
| return cSeqSizeEstimate + sequencesSectionHeaderSize; |
| } |
| |
| typedef struct { |
| size_t estLitSize; |
| size_t estBlockSize; |
| } EstimatedBlockSize; |
| static EstimatedBlockSize ZSTD_estimateSubBlockSize(const BYTE* literals, size_t litSize, |
| const BYTE* ofCodeTable, |
| const BYTE* llCodeTable, |
| const BYTE* mlCodeTable, |
| size_t nbSeq, |
| const ZSTD_entropyCTables_t* entropy, |
| const ZSTD_entropyCTablesMetadata_t* entropyMetadata, |
| void* workspace, size_t wkspSize, |
| int writeLitEntropy, int writeSeqEntropy) |
| { |
| EstimatedBlockSize ebs; |
| ebs.estLitSize = ZSTD_estimateSubBlockSize_literal(literals, litSize, |
| &entropy->huf, &entropyMetadata->hufMetadata, |
| workspace, wkspSize, writeLitEntropy); |
| ebs.estBlockSize = ZSTD_estimateSubBlockSize_sequences(ofCodeTable, llCodeTable, mlCodeTable, |
| nbSeq, &entropy->fse, &entropyMetadata->fseMetadata, |
| workspace, wkspSize, writeSeqEntropy); |
| ebs.estBlockSize += ebs.estLitSize + ZSTD_blockHeaderSize; |
| return ebs; |
| } |
| |
| static int ZSTD_needSequenceEntropyTables(ZSTD_fseCTablesMetadata_t const* fseMetadata) |
| { |
| if (fseMetadata->llType == set_compressed || fseMetadata->llType == set_rle) |
| return 1; |
| if (fseMetadata->mlType == set_compressed || fseMetadata->mlType == set_rle) |
| return 1; |
| if (fseMetadata->ofType == set_compressed || fseMetadata->ofType == set_rle) |
| return 1; |
| return 0; |
| } |
| |
| static size_t countLiterals(SeqStore_t const* seqStore, const SeqDef* sp, size_t seqCount) |
| { |
| size_t n, total = 0; |
| assert(sp != NULL); |
| for (n=0; n<seqCount; n++) { |
| total += ZSTD_getSequenceLength(seqStore, sp+n).litLength; |
| } |
| DEBUGLOG(6, "countLiterals for %zu sequences from %p => %zu bytes", seqCount, (const void*)sp, total); |
| return total; |
| } |
| |
| #define BYTESCALE 256 |
| |
| static size_t sizeBlockSequences(const SeqDef* sp, size_t nbSeqs, |
| size_t targetBudget, size_t avgLitCost, size_t avgSeqCost, |
| int firstSubBlock) |
| { |
| size_t n, budget = 0, inSize=0; |
| /* entropy headers */ |
| size_t const headerSize = (size_t)firstSubBlock * 120 * BYTESCALE; /* generous estimate */ |
| assert(firstSubBlock==0 || firstSubBlock==1); |
| budget += headerSize; |
| |
| /* first sequence => at least one sequence*/ |
| budget += sp[0].litLength * avgLitCost + avgSeqCost; |
| if (budget > targetBudget) return 1; |
| inSize = sp[0].litLength + (sp[0].mlBase+MINMATCH); |
| |
| /* loop over sequences */ |
| for (n=1; n<nbSeqs; n++) { |
| size_t currentCost = sp[n].litLength * avgLitCost + avgSeqCost; |
| budget += currentCost; |
| inSize += sp[n].litLength + (sp[n].mlBase+MINMATCH); |
| /* stop when sub-block budget is reached */ |
| if ( (budget > targetBudget) |
| /* though continue to expand until the sub-block is deemed compressible */ |
| && (budget < inSize * BYTESCALE) ) |
| break; |
| } |
| |
| return n; |
| } |
| |
| /** ZSTD_compressSubBlock_multi() : |
| * Breaks super-block into multiple sub-blocks and compresses them. |
| * Entropy will be written into the first block. |
| * The following blocks use repeat_mode to compress. |
| * Sub-blocks are all compressed, except the last one when beneficial. |
| * @return : compressed size of the super block (which features multiple ZSTD blocks) |
| * or 0 if it failed to compress. */ |
| static size_t ZSTD_compressSubBlock_multi(const SeqStore_t* seqStorePtr, |
| const ZSTD_compressedBlockState_t* prevCBlock, |
| ZSTD_compressedBlockState_t* nextCBlock, |
| const ZSTD_entropyCTablesMetadata_t* entropyMetadata, |
| const ZSTD_CCtx_params* cctxParams, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| const int bmi2, U32 lastBlock, |
| void* workspace, size_t wkspSize) |
| { |
| const SeqDef* const sstart = seqStorePtr->sequencesStart; |
| const SeqDef* const send = seqStorePtr->sequences; |
| const SeqDef* sp = sstart; /* tracks progresses within seqStorePtr->sequences */ |
| size_t const nbSeqs = (size_t)(send - sstart); |
| const BYTE* const lstart = seqStorePtr->litStart; |
| const BYTE* const lend = seqStorePtr->lit; |
| const BYTE* lp = lstart; |
| size_t const nbLiterals = (size_t)(lend - lstart); |
| BYTE const* ip = (BYTE const*)src; |
| BYTE const* const iend = ip + srcSize; |
| BYTE* const ostart = (BYTE*)dst; |
| BYTE* const oend = ostart + dstCapacity; |
| BYTE* op = ostart; |
| const BYTE* llCodePtr = seqStorePtr->llCode; |
| const BYTE* mlCodePtr = seqStorePtr->mlCode; |
| const BYTE* ofCodePtr = seqStorePtr->ofCode; |
| size_t const minTarget = ZSTD_TARGETCBLOCKSIZE_MIN; /* enforce minimum size, to reduce undesirable side effects */ |
| size_t const targetCBlockSize = MAX(minTarget, cctxParams->targetCBlockSize); |
| int writeLitEntropy = (entropyMetadata->hufMetadata.hType == set_compressed); |
| int writeSeqEntropy = 1; |
| |
| DEBUGLOG(5, "ZSTD_compressSubBlock_multi (srcSize=%u, litSize=%u, nbSeq=%u)", |
| (unsigned)srcSize, (unsigned)(lend-lstart), (unsigned)(send-sstart)); |
| |
| /* let's start by a general estimation for the full block */ |
| if (nbSeqs > 0) { |
| EstimatedBlockSize const ebs = |
| ZSTD_estimateSubBlockSize(lp, nbLiterals, |
| ofCodePtr, llCodePtr, mlCodePtr, nbSeqs, |
| &nextCBlock->entropy, entropyMetadata, |
| workspace, wkspSize, |
| writeLitEntropy, writeSeqEntropy); |
| /* quick estimation */ |
| size_t const avgLitCost = nbLiterals ? (ebs.estLitSize * BYTESCALE) / nbLiterals : BYTESCALE; |
| size_t const avgSeqCost = ((ebs.estBlockSize - ebs.estLitSize) * BYTESCALE) / nbSeqs; |
| const size_t nbSubBlocks = MAX((ebs.estBlockSize + (targetCBlockSize/2)) / targetCBlockSize, 1); |
| size_t n, avgBlockBudget, blockBudgetSupp=0; |
| avgBlockBudget = (ebs.estBlockSize * BYTESCALE) / nbSubBlocks; |
| DEBUGLOG(5, "estimated fullblock size=%u bytes ; avgLitCost=%.2f ; avgSeqCost=%.2f ; targetCBlockSize=%u, nbSubBlocks=%u ; avgBlockBudget=%.0f bytes", |
| (unsigned)ebs.estBlockSize, (double)avgLitCost/BYTESCALE, (double)avgSeqCost/BYTESCALE, |
| (unsigned)targetCBlockSize, (unsigned)nbSubBlocks, (double)avgBlockBudget/BYTESCALE); |
| /* simplification: if estimates states that the full superblock doesn't compress, just bail out immediately |
| * this will result in the production of a single uncompressed block covering @srcSize.*/ |
| if (ebs.estBlockSize > srcSize) return 0; |
| |
| /* compress and write sub-blocks */ |
| assert(nbSubBlocks>0); |
| for (n=0; n < nbSubBlocks-1; n++) { |
| /* determine nb of sequences for current sub-block + nbLiterals from next sequence */ |
| size_t const seqCount = sizeBlockSequences(sp, (size_t)(send-sp), |
| avgBlockBudget + blockBudgetSupp, avgLitCost, avgSeqCost, n==0); |
| /* if reached last sequence : break to last sub-block (simplification) */ |
| assert(seqCount <= (size_t)(send-sp)); |
| if (sp + seqCount == send) break; |
| assert(seqCount > 0); |
| /* compress sub-block */ |
| { int litEntropyWritten = 0; |
| int seqEntropyWritten = 0; |
| size_t litSize = countLiterals(seqStorePtr, sp, seqCount); |
| const size_t decompressedSize = |
| ZSTD_seqDecompressedSize(seqStorePtr, sp, seqCount, litSize, 0); |
| size_t const cSize = ZSTD_compressSubBlock(&nextCBlock->entropy, entropyMetadata, |
| sp, seqCount, |
| lp, litSize, |
| llCodePtr, mlCodePtr, ofCodePtr, |
| cctxParams, |
| op, (size_t)(oend-op), |
| bmi2, writeLitEntropy, writeSeqEntropy, |
| &litEntropyWritten, &seqEntropyWritten, |
| 0); |
| FORWARD_IF_ERROR(cSize, "ZSTD_compressSubBlock failed"); |
| |
| /* check compressibility, update state components */ |
| if (cSize > 0 && cSize < decompressedSize) { |
| DEBUGLOG(5, "Committed sub-block compressing %u bytes => %u bytes", |
| (unsigned)decompressedSize, (unsigned)cSize); |
| assert(ip + decompressedSize <= iend); |
| ip += decompressedSize; |
| lp += litSize; |
| op += cSize; |
| llCodePtr += seqCount; |
| mlCodePtr += seqCount; |
| ofCodePtr += seqCount; |
| /* Entropy only needs to be written once */ |
| if (litEntropyWritten) { |
| writeLitEntropy = 0; |
| } |
| if (seqEntropyWritten) { |
| writeSeqEntropy = 0; |
| } |
| sp += seqCount; |
| blockBudgetSupp = 0; |
| } } |
| /* otherwise : do not compress yet, coalesce current sub-block with following one */ |
| } |
| } /* if (nbSeqs > 0) */ |
| |
| /* write last block */ |
| DEBUGLOG(5, "Generate last sub-block: %u sequences remaining", (unsigned)(send - sp)); |
| { int litEntropyWritten = 0; |
| int seqEntropyWritten = 0; |
| size_t litSize = (size_t)(lend - lp); |
| size_t seqCount = (size_t)(send - sp); |
| const size_t decompressedSize = |
| ZSTD_seqDecompressedSize(seqStorePtr, sp, seqCount, litSize, 1); |
| size_t const cSize = ZSTD_compressSubBlock(&nextCBlock->entropy, entropyMetadata, |
| sp, seqCount, |
| lp, litSize, |
| llCodePtr, mlCodePtr, ofCodePtr, |
| cctxParams, |
| op, (size_t)(oend-op), |
| bmi2, writeLitEntropy, writeSeqEntropy, |
| &litEntropyWritten, &seqEntropyWritten, |
| lastBlock); |
| FORWARD_IF_ERROR(cSize, "ZSTD_compressSubBlock failed"); |
| |
| /* update pointers, the nb of literals borrowed from next sequence must be preserved */ |
| if (cSize > 0 && cSize < decompressedSize) { |
| DEBUGLOG(5, "Last sub-block compressed %u bytes => %u bytes", |
| (unsigned)decompressedSize, (unsigned)cSize); |
| assert(ip + decompressedSize <= iend); |
| ip += decompressedSize; |
| lp += litSize; |
| op += cSize; |
| llCodePtr += seqCount; |
| mlCodePtr += seqCount; |
| ofCodePtr += seqCount; |
| /* Entropy only needs to be written once */ |
| if (litEntropyWritten) { |
| writeLitEntropy = 0; |
| } |
| if (seqEntropyWritten) { |
| writeSeqEntropy = 0; |
| } |
| sp += seqCount; |
| } |
| } |
| |
| |
| if (writeLitEntropy) { |
| DEBUGLOG(5, "Literal entropy tables were never written"); |
| ZSTD_memcpy(&nextCBlock->entropy.huf, &prevCBlock->entropy.huf, sizeof(prevCBlock->entropy.huf)); |
| } |
| if (writeSeqEntropy && ZSTD_needSequenceEntropyTables(&entropyMetadata->fseMetadata)) { |
| /* If we haven't written our entropy tables, then we've violated our contract and |
| * must emit an uncompressed block. |
| */ |
| DEBUGLOG(5, "Sequence entropy tables were never written => cancel, emit an uncompressed block"); |
| return 0; |
| } |
| |
| if (ip < iend) { |
| /* some data left : last part of the block sent uncompressed */ |
| size_t const rSize = (size_t)((iend - ip)); |
| size_t const cSize = ZSTD_noCompressBlock(op, (size_t)(oend - op), ip, rSize, lastBlock); |
| DEBUGLOG(5, "Generate last uncompressed sub-block of %u bytes", (unsigned)(rSize)); |
| FORWARD_IF_ERROR(cSize, "ZSTD_noCompressBlock failed"); |
| assert(cSize != 0); |
| op += cSize; |
| /* We have to regenerate the repcodes because we've skipped some sequences */ |
| if (sp < send) { |
| const SeqDef* seq; |
| Repcodes_t rep; |
| ZSTD_memcpy(&rep, prevCBlock->rep, sizeof(rep)); |
| for (seq = sstart; seq < sp; ++seq) { |
| ZSTD_updateRep(rep.rep, seq->offBase, ZSTD_getSequenceLength(seqStorePtr, seq).litLength == 0); |
| } |
| ZSTD_memcpy(nextCBlock->rep, &rep, sizeof(rep)); |
| } |
| } |
| |
| DEBUGLOG(5, "ZSTD_compressSubBlock_multi compressed all subBlocks: total compressed size = %u", |
| (unsigned)(op-ostart)); |
| return (size_t)(op-ostart); |
| } |
| |
| size_t ZSTD_compressSuperBlock(ZSTD_CCtx* zc, |
| void* dst, size_t dstCapacity, |
| const void* src, size_t srcSize, |
| unsigned lastBlock) |
| { |
| ZSTD_entropyCTablesMetadata_t entropyMetadata; |
| |
| FORWARD_IF_ERROR(ZSTD_buildBlockEntropyStats(&zc->seqStore, |
| &zc->blockState.prevCBlock->entropy, |
| &zc->blockState.nextCBlock->entropy, |
| &zc->appliedParams, |
| &entropyMetadata, |
| zc->tmpWorkspace, zc->tmpWkspSize /* statically allocated in resetCCtx */), ""); |
| |
| return ZSTD_compressSubBlock_multi(&zc->seqStore, |
| zc->blockState.prevCBlock, |
| zc->blockState.nextCBlock, |
| &entropyMetadata, |
| &zc->appliedParams, |
| dst, dstCapacity, |
| src, srcSize, |
| zc->bmi2, lastBlock, |
| zc->tmpWorkspace, zc->tmpWkspSize /* statically allocated in resetCCtx */); |
| } |
