diff options
Diffstat (limited to 'lib/zstd/compress/zstd_compress_superblock.c')
| -rw-r--r-- | lib/zstd/compress/zstd_compress_superblock.c | 689 |
1 files changed, 689 insertions, 0 deletions
diff --git a/lib/zstd/compress/zstd_compress_superblock.c b/lib/zstd/compress/zstd_compress_superblock.c new file mode 100644 index 000000000000..dc12d64e935c --- /dev/null +++ b/lib/zstd/compress/zstd_compress_superblock.c @@ -0,0 +1,689 @@ +// SPDX-License-Identifier: GPL-2.0+ OR BSD-3-Clause +/* + * 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 */); +} |