688 lines
33 KiB
C
688 lines
33 KiB
C
/*
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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* All rights reserved.
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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*/
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/*-*************************************
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* Dependencies
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***************************************/
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#include "zstd_compress_superblock.h"
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#include "../common/zstd_internal.h" /* ZSTD_getSequenceLength */
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#include "hist.h" /* HIST_countFast_wksp */
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#include "zstd_compress_internal.h" /* ZSTD_[huf|fse|entropy]CTablesMetadata_t */
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#include "zstd_compress_sequences.h"
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#include "zstd_compress_literals.h"
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/** ZSTD_compressSubBlock_literal() :
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* Compresses literals section for a sub-block.
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* When we have to write the Huffman table we will sometimes choose a header
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* size larger than necessary. This is because we have to pick the header size
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* before we know the table size + compressed size, so we have a bound on the
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* table size. If we guessed incorrectly, we fall back to uncompressed literals.
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*
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* We write the header when writeEntropy=1 and set entropyWritten=1 when we succeeded
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* in writing the header, otherwise it is set to 0.
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*
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* hufMetadata->hType has literals block type info.
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* If it is set_basic, all sub-blocks literals section will be Raw_Literals_Block.
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* If it is set_rle, all sub-blocks literals section will be RLE_Literals_Block.
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* If it is set_compressed, first sub-block's literals section will be Compressed_Literals_Block
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* If it is set_compressed, first sub-block's literals section will be Treeless_Literals_Block
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* and the following sub-blocks' literals sections will be Treeless_Literals_Block.
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* @return : compressed size of literals section of a sub-block
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* Or 0 if unable to compress.
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* Or error code */
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static size_t
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ZSTD_compressSubBlock_literal(const HUF_CElt* hufTable,
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const ZSTD_hufCTablesMetadata_t* hufMetadata,
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const BYTE* literals, size_t litSize,
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void* dst, size_t dstSize,
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const int bmi2, int writeEntropy, int* entropyWritten)
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{
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size_t const header = writeEntropy ? 200 : 0;
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size_t const lhSize = 3 + (litSize >= (1 KB - header)) + (litSize >= (16 KB - header));
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BYTE* const ostart = (BYTE*)dst;
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BYTE* const oend = ostart + dstSize;
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BYTE* op = ostart + lhSize;
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U32 const singleStream = lhSize == 3;
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symbolEncodingType_e hType = writeEntropy ? hufMetadata->hType : set_repeat;
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size_t cLitSize = 0;
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DEBUGLOG(5, "ZSTD_compressSubBlock_literal (litSize=%zu, lhSize=%zu, writeEntropy=%d)", litSize, lhSize, writeEntropy);
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*entropyWritten = 0;
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if (litSize == 0 || hufMetadata->hType == set_basic) {
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DEBUGLOG(5, "ZSTD_compressSubBlock_literal using raw literal");
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return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
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} else if (hufMetadata->hType == set_rle) {
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DEBUGLOG(5, "ZSTD_compressSubBlock_literal using rle literal");
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return ZSTD_compressRleLiteralsBlock(dst, dstSize, literals, litSize);
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}
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assert(litSize > 0);
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assert(hufMetadata->hType == set_compressed || hufMetadata->hType == set_repeat);
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if (writeEntropy && hufMetadata->hType == set_compressed) {
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ZSTD_memcpy(op, hufMetadata->hufDesBuffer, hufMetadata->hufDesSize);
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op += hufMetadata->hufDesSize;
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cLitSize += hufMetadata->hufDesSize;
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DEBUGLOG(5, "ZSTD_compressSubBlock_literal (hSize=%zu)", hufMetadata->hufDesSize);
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}
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{ int const flags = bmi2 ? HUF_flags_bmi2 : 0;
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const size_t cSize = singleStream ? HUF_compress1X_usingCTable(op, (size_t)(oend-op), literals, litSize, hufTable, flags)
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: HUF_compress4X_usingCTable(op, (size_t)(oend-op), literals, litSize, hufTable, flags);
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op += cSize;
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cLitSize += cSize;
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if (cSize == 0 || ERR_isError(cSize)) {
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DEBUGLOG(5, "Failed to write entropy tables %s", ZSTD_getErrorName(cSize));
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return 0;
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}
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/* If we expand and we aren't writing a header then emit uncompressed */
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if (!writeEntropy && cLitSize >= litSize) {
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DEBUGLOG(5, "ZSTD_compressSubBlock_literal using raw literal because uncompressible");
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return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
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}
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/* If we are writing headers then allow expansion that doesn't change our header size. */
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if (lhSize < (size_t)(3 + (cLitSize >= 1 KB) + (cLitSize >= 16 KB))) {
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assert(cLitSize > litSize);
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DEBUGLOG(5, "Literals expanded beyond allowed header size");
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return ZSTD_noCompressLiterals(dst, dstSize, literals, litSize);
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}
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DEBUGLOG(5, "ZSTD_compressSubBlock_literal (cSize=%zu)", cSize);
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}
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/* Build header */
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switch(lhSize)
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{
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case 3: /* 2 - 2 - 10 - 10 */
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{ U32 const lhc = hType + ((U32)(!singleStream) << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<14);
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MEM_writeLE24(ostart, lhc);
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break;
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}
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case 4: /* 2 - 2 - 14 - 14 */
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{ U32 const lhc = hType + (2 << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<18);
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MEM_writeLE32(ostart, lhc);
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break;
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}
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case 5: /* 2 - 2 - 18 - 18 */
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{ U32 const lhc = hType + (3 << 2) + ((U32)litSize<<4) + ((U32)cLitSize<<22);
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MEM_writeLE32(ostart, lhc);
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ostart[4] = (BYTE)(cLitSize >> 10);
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break;
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}
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default: /* not possible : lhSize is {3,4,5} */
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assert(0);
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}
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*entropyWritten = 1;
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DEBUGLOG(5, "Compressed literals: %u -> %u", (U32)litSize, (U32)(op-ostart));
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return (size_t)(op-ostart);
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}
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static size_t
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ZSTD_seqDecompressedSize(seqStore_t const* seqStore,
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const seqDef* sequences, size_t nbSeqs,
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size_t litSize, int lastSubBlock)
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{
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size_t matchLengthSum = 0;
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size_t litLengthSum = 0;
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size_t n;
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for (n=0; n<nbSeqs; n++) {
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const ZSTD_sequenceLength seqLen = ZSTD_getSequenceLength(seqStore, sequences+n);
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litLengthSum += seqLen.litLength;
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matchLengthSum += seqLen.matchLength;
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}
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DEBUGLOG(5, "ZSTD_seqDecompressedSize: %u sequences from %p: %u literals + %u matchlength",
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(unsigned)nbSeqs, (const void*)sequences,
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(unsigned)litLengthSum, (unsigned)matchLengthSum);
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if (!lastSubBlock)
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assert(litLengthSum == litSize);
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else
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assert(litLengthSum <= litSize);
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(void)litLengthSum;
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return matchLengthSum + litSize;
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}
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/** ZSTD_compressSubBlock_sequences() :
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* Compresses sequences section for a sub-block.
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* fseMetadata->llType, fseMetadata->ofType, and fseMetadata->mlType have
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* symbol compression modes for the super-block.
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* The first successfully compressed block will have these in its header.
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* We set entropyWritten=1 when we succeed in compressing the sequences.
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* The following sub-blocks will always have repeat mode.
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* @return : compressed size of sequences section of a sub-block
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* Or 0 if it is unable to compress
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* Or error code. */
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static size_t
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ZSTD_compressSubBlock_sequences(const ZSTD_fseCTables_t* fseTables,
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const ZSTD_fseCTablesMetadata_t* fseMetadata,
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const seqDef* sequences, size_t nbSeq,
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const BYTE* llCode, const BYTE* mlCode, const BYTE* ofCode,
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const ZSTD_CCtx_params* cctxParams,
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void* dst, size_t dstCapacity,
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const int bmi2, int writeEntropy, int* entropyWritten)
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{
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const int longOffsets = cctxParams->cParams.windowLog > STREAM_ACCUMULATOR_MIN;
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BYTE* const ostart = (BYTE*)dst;
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BYTE* const oend = ostart + dstCapacity;
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BYTE* op = ostart;
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BYTE* seqHead;
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DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (nbSeq=%zu, writeEntropy=%d, longOffsets=%d)", nbSeq, writeEntropy, longOffsets);
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*entropyWritten = 0;
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/* Sequences Header */
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RETURN_ERROR_IF((oend-op) < 3 /*max nbSeq Size*/ + 1 /*seqHead*/,
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dstSize_tooSmall, "");
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if (nbSeq < 128)
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*op++ = (BYTE)nbSeq;
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else if (nbSeq < LONGNBSEQ)
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op[0] = (BYTE)((nbSeq>>8) + 0x80), op[1] = (BYTE)nbSeq, op+=2;
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else
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op[0]=0xFF, MEM_writeLE16(op+1, (U16)(nbSeq - LONGNBSEQ)), op+=3;
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if (nbSeq==0) {
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return (size_t)(op - ostart);
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}
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/* seqHead : flags for FSE encoding type */
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seqHead = op++;
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DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (seqHeadSize=%u)", (unsigned)(op-ostart));
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if (writeEntropy) {
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const U32 LLtype = fseMetadata->llType;
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const U32 Offtype = fseMetadata->ofType;
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const U32 MLtype = fseMetadata->mlType;
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DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (fseTablesSize=%zu)", fseMetadata->fseTablesSize);
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*seqHead = (BYTE)((LLtype<<6) + (Offtype<<4) + (MLtype<<2));
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ZSTD_memcpy(op, fseMetadata->fseTablesBuffer, fseMetadata->fseTablesSize);
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op += fseMetadata->fseTablesSize;
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} else {
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const U32 repeat = set_repeat;
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*seqHead = (BYTE)((repeat<<6) + (repeat<<4) + (repeat<<2));
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}
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{ size_t const bitstreamSize = ZSTD_encodeSequences(
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op, (size_t)(oend - op),
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fseTables->matchlengthCTable, mlCode,
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fseTables->offcodeCTable, ofCode,
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fseTables->litlengthCTable, llCode,
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sequences, nbSeq,
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longOffsets, bmi2);
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FORWARD_IF_ERROR(bitstreamSize, "ZSTD_encodeSequences failed");
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op += bitstreamSize;
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/* zstd versions <= 1.3.4 mistakenly report corruption when
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* FSE_readNCount() receives a buffer < 4 bytes.
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* Fixed by https://github.com/facebook/zstd/pull/1146.
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* This can happen when the last set_compressed table present is 2
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* bytes and the bitstream is only one byte.
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* In this exceedingly rare case, we will simply emit an uncompressed
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* block, since it isn't worth optimizing.
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*/
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#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
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if (writeEntropy && fseMetadata->lastCountSize && fseMetadata->lastCountSize + bitstreamSize < 4) {
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/* NCountSize >= 2 && bitstreamSize > 0 ==> lastCountSize == 3 */
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assert(fseMetadata->lastCountSize + bitstreamSize == 3);
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DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.3.4 by "
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"emitting an uncompressed block.");
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return 0;
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}
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#endif
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DEBUGLOG(5, "ZSTD_compressSubBlock_sequences (bitstreamSize=%zu)", bitstreamSize);
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}
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/* zstd versions <= 1.4.0 mistakenly report error when
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* sequences section body size is less than 3 bytes.
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* Fixed by https://github.com/facebook/zstd/pull/1664.
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* This can happen when the previous sequences section block is compressed
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* with rle mode and the current block's sequences section is compressed
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* with repeat mode where sequences section body size can be 1 byte.
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*/
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#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
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if (op-seqHead < 4) {
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DEBUGLOG(5, "Avoiding bug in zstd decoder in versions <= 1.4.0 by emitting "
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"an uncompressed block when sequences are < 4 bytes");
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return 0;
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}
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#endif
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*entropyWritten = 1;
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return (size_t)(op - ostart);
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}
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/** ZSTD_compressSubBlock() :
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* Compresses a single sub-block.
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* @return : compressed size of the sub-block
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* Or 0 if it failed to compress. */
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static size_t ZSTD_compressSubBlock(const ZSTD_entropyCTables_t* entropy,
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const ZSTD_entropyCTablesMetadata_t* entropyMetadata,
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const seqDef* sequences, size_t nbSeq,
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const BYTE* literals, size_t litSize,
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const BYTE* llCode, const BYTE* mlCode, const BYTE* ofCode,
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const ZSTD_CCtx_params* cctxParams,
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void* dst, size_t dstCapacity,
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const int bmi2,
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int writeLitEntropy, int writeSeqEntropy,
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int* litEntropyWritten, int* seqEntropyWritten,
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U32 lastBlock)
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{
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BYTE* const ostart = (BYTE*)dst;
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BYTE* const oend = ostart + dstCapacity;
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BYTE* op = ostart + ZSTD_blockHeaderSize;
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DEBUGLOG(5, "ZSTD_compressSubBlock (litSize=%zu, nbSeq=%zu, writeLitEntropy=%d, writeSeqEntropy=%d, lastBlock=%d)",
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litSize, nbSeq, writeLitEntropy, writeSeqEntropy, lastBlock);
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{ size_t cLitSize = ZSTD_compressSubBlock_literal((const HUF_CElt*)entropy->huf.CTable,
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&entropyMetadata->hufMetadata, literals, litSize,
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op, (size_t)(oend-op),
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bmi2, writeLitEntropy, litEntropyWritten);
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FORWARD_IF_ERROR(cLitSize, "ZSTD_compressSubBlock_literal failed");
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if (cLitSize == 0) return 0;
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op += cLitSize;
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}
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{ size_t cSeqSize = ZSTD_compressSubBlock_sequences(&entropy->fse,
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&entropyMetadata->fseMetadata,
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sequences, nbSeq,
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llCode, mlCode, ofCode,
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cctxParams,
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op, (size_t)(oend-op),
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bmi2, writeSeqEntropy, seqEntropyWritten);
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FORWARD_IF_ERROR(cSeqSize, "ZSTD_compressSubBlock_sequences failed");
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if (cSeqSize == 0) return 0;
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op += cSeqSize;
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}
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/* Write block header */
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{ size_t cSize = (size_t)(op-ostart) - ZSTD_blockHeaderSize;
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U32 const cBlockHeader24 = lastBlock + (((U32)bt_compressed)<<1) + (U32)(cSize << 3);
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MEM_writeLE24(ostart, cBlockHeader24);
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}
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return (size_t)(op-ostart);
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}
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static size_t ZSTD_estimateSubBlockSize_literal(const BYTE* literals, size_t litSize,
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const ZSTD_hufCTables_t* huf,
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const ZSTD_hufCTablesMetadata_t* hufMetadata,
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void* workspace, size_t wkspSize,
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int writeEntropy)
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{
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unsigned* const countWksp = (unsigned*)workspace;
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unsigned maxSymbolValue = 255;
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size_t literalSectionHeaderSize = 3; /* Use hard coded size of 3 bytes */
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if (hufMetadata->hType == set_basic) return litSize;
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else if (hufMetadata->hType == set_rle) return 1;
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else if (hufMetadata->hType == set_compressed || hufMetadata->hType == set_repeat) {
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size_t const largest = HIST_count_wksp (countWksp, &maxSymbolValue, (const BYTE*)literals, litSize, workspace, wkspSize);
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if (ZSTD_isError(largest)) return litSize;
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{ size_t cLitSizeEstimate = HUF_estimateCompressedSize((const HUF_CElt*)huf->CTable, countWksp, maxSymbolValue);
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if (writeEntropy) cLitSizeEstimate += hufMetadata->hufDesSize;
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return cLitSizeEstimate + literalSectionHeaderSize;
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} }
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assert(0); /* impossible */
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return 0;
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}
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static size_t ZSTD_estimateSubBlockSize_symbolType(symbolEncodingType_e type,
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const BYTE* codeTable, unsigned maxCode,
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size_t nbSeq, const FSE_CTable* fseCTable,
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const U8* additionalBits,
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short const* defaultNorm, U32 defaultNormLog, U32 defaultMax,
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void* workspace, size_t wkspSize)
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{
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unsigned* const countWksp = (unsigned*)workspace;
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const BYTE* ctp = codeTable;
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const BYTE* const ctStart = ctp;
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const BYTE* const ctEnd = ctStart + nbSeq;
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size_t cSymbolTypeSizeEstimateInBits = 0;
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unsigned max = maxCode;
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HIST_countFast_wksp(countWksp, &max, codeTable, nbSeq, workspace, wkspSize); /* can't fail */
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if (type == set_basic) {
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/* We selected this encoding type, so it must be valid. */
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assert(max <= defaultMax);
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cSymbolTypeSizeEstimateInBits = max <= defaultMax
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? ZSTD_crossEntropyCost(defaultNorm, defaultNormLog, countWksp, max)
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: ERROR(GENERIC);
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} else if (type == set_rle) {
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cSymbolTypeSizeEstimateInBits = 0;
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} else if (type == set_compressed || type == set_repeat) {
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cSymbolTypeSizeEstimateInBits = ZSTD_fseBitCost(fseCTable, countWksp, max);
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}
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if (ZSTD_isError(cSymbolTypeSizeEstimateInBits)) return nbSeq * 10;
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while (ctp < ctEnd) {
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if (additionalBits) cSymbolTypeSizeEstimateInBits += additionalBits[*ctp];
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else cSymbolTypeSizeEstimateInBits += *ctp; /* for offset, offset code is also the number of additional bits */
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ctp++;
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}
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return cSymbolTypeSizeEstimateInBits / 8;
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}
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static size_t ZSTD_estimateSubBlockSize_sequences(const BYTE* ofCodeTable,
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const BYTE* llCodeTable,
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const BYTE* mlCodeTable,
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size_t nbSeq,
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const ZSTD_fseCTables_t* fseTables,
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const ZSTD_fseCTablesMetadata_t* fseMetadata,
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void* workspace, size_t wkspSize,
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int writeEntropy)
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{
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size_t const sequencesSectionHeaderSize = 3; /* Use hard coded size of 3 bytes */
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size_t cSeqSizeEstimate = 0;
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if (nbSeq == 0) return sequencesSectionHeaderSize;
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cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->ofType, ofCodeTable, MaxOff,
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nbSeq, fseTables->offcodeCTable, NULL,
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OF_defaultNorm, OF_defaultNormLog, DefaultMaxOff,
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workspace, wkspSize);
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cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->llType, llCodeTable, MaxLL,
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nbSeq, fseTables->litlengthCTable, LL_bits,
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LL_defaultNorm, LL_defaultNormLog, MaxLL,
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workspace, wkspSize);
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cSeqSizeEstimate += ZSTD_estimateSubBlockSize_symbolType(fseMetadata->mlType, mlCodeTable, MaxML,
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nbSeq, fseTables->matchlengthCTable, ML_bits,
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ML_defaultNorm, ML_defaultNormLog, MaxML,
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workspace, wkspSize);
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if (writeEntropy) cSeqSizeEstimate += fseMetadata->fseTablesSize;
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return cSeqSizeEstimate + sequencesSectionHeaderSize;
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}
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typedef struct {
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size_t estLitSize;
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size_t estBlockSize;
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} EstimatedBlockSize;
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static EstimatedBlockSize ZSTD_estimateSubBlockSize(const BYTE* literals, size_t litSize,
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const BYTE* ofCodeTable,
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const BYTE* llCodeTable,
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const BYTE* mlCodeTable,
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size_t nbSeq,
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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->entropyWorkspace, ENTROPY_WORKSPACE_SIZE /* 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->entropyWorkspace, ENTROPY_WORKSPACE_SIZE /* statically allocated in resetCCtx */);
|
|
}
|