1541 строка
65 KiB
C
1541 строка
65 KiB
C
/*
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* Copyright (c) Yann Collet, Facebook, Inc.
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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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/* zstd_decompress_block :
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* this module takes care of decompressing _compressed_ block */
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/*-*******************************************************
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* Dependencies
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*********************************************************/
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#include "../common/zstd_deps.h" /* ZSTD_memcpy, ZSTD_memmove, ZSTD_memset */
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#include "../common/compiler.h" /* prefetch */
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#include "../common/cpu.h" /* bmi2 */
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#include "../common/mem.h" /* low level memory routines */
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#define FSE_STATIC_LINKING_ONLY
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#include "../common/fse.h"
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#define HUF_STATIC_LINKING_ONLY
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#include "../common/huf.h"
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#include "../common/zstd_internal.h"
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#include "zstd_decompress_internal.h" /* ZSTD_DCtx */
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#include "zstd_ddict.h" /* ZSTD_DDictDictContent */
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#include "zstd_decompress_block.h"
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/*_*******************************************************
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* Macros
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**********************************************************/
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/* These two optional macros force the use one way or another of the two
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* ZSTD_decompressSequences implementations. You can't force in both directions
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* at the same time.
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*/
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#if defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
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defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
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#error "Cannot force the use of the short and the long ZSTD_decompressSequences variants!"
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#endif
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/*_*******************************************************
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* Memory operations
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**********************************************************/
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static void ZSTD_copy4(void* dst, const void* src) { ZSTD_memcpy(dst, src, 4); }
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/*-*************************************************************
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* Block decoding
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***************************************************************/
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/*! ZSTD_getcBlockSize() :
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* Provides the size of compressed block from block header `src` */
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size_t ZSTD_getcBlockSize(const void* src, size_t srcSize,
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blockProperties_t* bpPtr)
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{
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RETURN_ERROR_IF(srcSize < ZSTD_blockHeaderSize, srcSize_wrong, "");
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{ U32 const cBlockHeader = MEM_readLE24(src);
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U32 const cSize = cBlockHeader >> 3;
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bpPtr->lastBlock = cBlockHeader & 1;
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bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3);
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bpPtr->origSize = cSize; /* only useful for RLE */
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if (bpPtr->blockType == bt_rle) return 1;
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RETURN_ERROR_IF(bpPtr->blockType == bt_reserved, corruption_detected, "");
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return cSize;
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}
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}
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/* Hidden declaration for fullbench */
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size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
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const void* src, size_t srcSize);
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/*! ZSTD_decodeLiteralsBlock() :
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* @return : nb of bytes read from src (< srcSize )
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* note : symbol not declared but exposed for fullbench */
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size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx* dctx,
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const void* src, size_t srcSize) /* note : srcSize < BLOCKSIZE */
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{
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DEBUGLOG(5, "ZSTD_decodeLiteralsBlock");
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RETURN_ERROR_IF(srcSize < MIN_CBLOCK_SIZE, corruption_detected, "");
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{ const BYTE* const istart = (const BYTE*) src;
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symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3);
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switch(litEncType)
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{
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case set_repeat:
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DEBUGLOG(5, "set_repeat flag : re-using stats from previous compressed literals block");
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RETURN_ERROR_IF(dctx->litEntropy==0, dictionary_corrupted, "");
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ZSTD_FALLTHROUGH;
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case set_compressed:
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RETURN_ERROR_IF(srcSize < 5, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3");
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{ size_t lhSize, litSize, litCSize;
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U32 singleStream=0;
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U32 const lhlCode = (istart[0] >> 2) & 3;
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U32 const lhc = MEM_readLE32(istart);
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size_t hufSuccess;
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switch(lhlCode)
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{
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case 0: case 1: default: /* note : default is impossible, since lhlCode into [0..3] */
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/* 2 - 2 - 10 - 10 */
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singleStream = !lhlCode;
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lhSize = 3;
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litSize = (lhc >> 4) & 0x3FF;
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litCSize = (lhc >> 14) & 0x3FF;
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break;
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case 2:
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/* 2 - 2 - 14 - 14 */
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lhSize = 4;
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litSize = (lhc >> 4) & 0x3FFF;
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litCSize = lhc >> 18;
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break;
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case 3:
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/* 2 - 2 - 18 - 18 */
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lhSize = 5;
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litSize = (lhc >> 4) & 0x3FFFF;
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litCSize = (lhc >> 22) + ((size_t)istart[4] << 10);
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break;
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}
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RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected, "");
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RETURN_ERROR_IF(litCSize + lhSize > srcSize, corruption_detected, "");
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/* prefetch huffman table if cold */
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if (dctx->ddictIsCold && (litSize > 768 /* heuristic */)) {
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PREFETCH_AREA(dctx->HUFptr, sizeof(dctx->entropy.hufTable));
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}
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if (litEncType==set_repeat) {
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if (singleStream) {
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hufSuccess = HUF_decompress1X_usingDTable_bmi2(
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dctx->litBuffer, litSize, istart+lhSize, litCSize,
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dctx->HUFptr, dctx->bmi2);
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} else {
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hufSuccess = HUF_decompress4X_usingDTable_bmi2(
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dctx->litBuffer, litSize, istart+lhSize, litCSize,
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dctx->HUFptr, dctx->bmi2);
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}
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} else {
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if (singleStream) {
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#if defined(HUF_FORCE_DECOMPRESS_X2)
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hufSuccess = HUF_decompress1X_DCtx_wksp(
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dctx->entropy.hufTable, dctx->litBuffer, litSize,
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istart+lhSize, litCSize, dctx->workspace,
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sizeof(dctx->workspace));
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#else
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hufSuccess = HUF_decompress1X1_DCtx_wksp_bmi2(
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dctx->entropy.hufTable, dctx->litBuffer, litSize,
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istart+lhSize, litCSize, dctx->workspace,
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sizeof(dctx->workspace), dctx->bmi2);
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#endif
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} else {
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hufSuccess = HUF_decompress4X_hufOnly_wksp_bmi2(
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dctx->entropy.hufTable, dctx->litBuffer, litSize,
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istart+lhSize, litCSize, dctx->workspace,
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sizeof(dctx->workspace), dctx->bmi2);
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}
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}
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RETURN_ERROR_IF(HUF_isError(hufSuccess), corruption_detected, "");
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dctx->litPtr = dctx->litBuffer;
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dctx->litSize = litSize;
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dctx->litEntropy = 1;
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if (litEncType==set_compressed) dctx->HUFptr = dctx->entropy.hufTable;
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ZSTD_memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
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return litCSize + lhSize;
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}
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case set_basic:
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{ size_t litSize, lhSize;
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U32 const lhlCode = ((istart[0]) >> 2) & 3;
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switch(lhlCode)
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{
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case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */
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lhSize = 1;
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litSize = istart[0] >> 3;
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break;
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case 1:
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lhSize = 2;
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litSize = MEM_readLE16(istart) >> 4;
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break;
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case 3:
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lhSize = 3;
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litSize = MEM_readLE24(istart) >> 4;
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break;
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}
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if (lhSize+litSize+WILDCOPY_OVERLENGTH > srcSize) { /* risk reading beyond src buffer with wildcopy */
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RETURN_ERROR_IF(litSize+lhSize > srcSize, corruption_detected, "");
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ZSTD_memcpy(dctx->litBuffer, istart+lhSize, litSize);
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dctx->litPtr = dctx->litBuffer;
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dctx->litSize = litSize;
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ZSTD_memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
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return lhSize+litSize;
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}
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/* direct reference into compressed stream */
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dctx->litPtr = istart+lhSize;
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dctx->litSize = litSize;
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return lhSize+litSize;
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}
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case set_rle:
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{ U32 const lhlCode = ((istart[0]) >> 2) & 3;
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size_t litSize, lhSize;
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switch(lhlCode)
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{
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case 0: case 2: default: /* note : default is impossible, since lhlCode into [0..3] */
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lhSize = 1;
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litSize = istart[0] >> 3;
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break;
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case 1:
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lhSize = 2;
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litSize = MEM_readLE16(istart) >> 4;
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break;
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case 3:
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lhSize = 3;
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litSize = MEM_readLE24(istart) >> 4;
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RETURN_ERROR_IF(srcSize<4, corruption_detected, "srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4");
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break;
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}
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RETURN_ERROR_IF(litSize > ZSTD_BLOCKSIZE_MAX, corruption_detected, "");
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ZSTD_memset(dctx->litBuffer, istart[lhSize], litSize + WILDCOPY_OVERLENGTH);
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dctx->litPtr = dctx->litBuffer;
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dctx->litSize = litSize;
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return lhSize+1;
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}
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default:
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RETURN_ERROR(corruption_detected, "impossible");
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}
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}
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}
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/* Default FSE distribution tables.
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* These are pre-calculated FSE decoding tables using default distributions as defined in specification :
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* https://github.com/facebook/zstd/blob/release/doc/zstd_compression_format.md#default-distributions
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* They were generated programmatically with following method :
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* - start from default distributions, present in /lib/common/zstd_internal.h
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* - generate tables normally, using ZSTD_buildFSETable()
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* - printout the content of tables
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* - pretify output, report below, test with fuzzer to ensure it's correct */
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/* Default FSE distribution table for Literal Lengths */
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static const ZSTD_seqSymbol LL_defaultDTable[(1<<LL_DEFAULTNORMLOG)+1] = {
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{ 1, 1, 1, LL_DEFAULTNORMLOG}, /* header : fastMode, tableLog */
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/* nextState, nbAddBits, nbBits, baseVal */
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{ 0, 0, 4, 0}, { 16, 0, 4, 0},
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{ 32, 0, 5, 1}, { 0, 0, 5, 3},
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{ 0, 0, 5, 4}, { 0, 0, 5, 6},
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{ 0, 0, 5, 7}, { 0, 0, 5, 9},
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{ 0, 0, 5, 10}, { 0, 0, 5, 12},
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{ 0, 0, 6, 14}, { 0, 1, 5, 16},
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{ 0, 1, 5, 20}, { 0, 1, 5, 22},
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{ 0, 2, 5, 28}, { 0, 3, 5, 32},
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{ 0, 4, 5, 48}, { 32, 6, 5, 64},
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{ 0, 7, 5, 128}, { 0, 8, 6, 256},
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{ 0, 10, 6, 1024}, { 0, 12, 6, 4096},
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{ 32, 0, 4, 0}, { 0, 0, 4, 1},
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{ 0, 0, 5, 2}, { 32, 0, 5, 4},
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{ 0, 0, 5, 5}, { 32, 0, 5, 7},
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{ 0, 0, 5, 8}, { 32, 0, 5, 10},
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{ 0, 0, 5, 11}, { 0, 0, 6, 13},
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{ 32, 1, 5, 16}, { 0, 1, 5, 18},
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{ 32, 1, 5, 22}, { 0, 2, 5, 24},
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{ 32, 3, 5, 32}, { 0, 3, 5, 40},
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{ 0, 6, 4, 64}, { 16, 6, 4, 64},
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{ 32, 7, 5, 128}, { 0, 9, 6, 512},
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{ 0, 11, 6, 2048}, { 48, 0, 4, 0},
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{ 16, 0, 4, 1}, { 32, 0, 5, 2},
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{ 32, 0, 5, 3}, { 32, 0, 5, 5},
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{ 32, 0, 5, 6}, { 32, 0, 5, 8},
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{ 32, 0, 5, 9}, { 32, 0, 5, 11},
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{ 32, 0, 5, 12}, { 0, 0, 6, 15},
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{ 32, 1, 5, 18}, { 32, 1, 5, 20},
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{ 32, 2, 5, 24}, { 32, 2, 5, 28},
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{ 32, 3, 5, 40}, { 32, 4, 5, 48},
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{ 0, 16, 6,65536}, { 0, 15, 6,32768},
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{ 0, 14, 6,16384}, { 0, 13, 6, 8192},
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}; /* LL_defaultDTable */
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/* Default FSE distribution table for Offset Codes */
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static const ZSTD_seqSymbol OF_defaultDTable[(1<<OF_DEFAULTNORMLOG)+1] = {
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{ 1, 1, 1, OF_DEFAULTNORMLOG}, /* header : fastMode, tableLog */
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/* nextState, nbAddBits, nbBits, baseVal */
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{ 0, 0, 5, 0}, { 0, 6, 4, 61},
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{ 0, 9, 5, 509}, { 0, 15, 5,32765},
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{ 0, 21, 5,2097149}, { 0, 3, 5, 5},
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{ 0, 7, 4, 125}, { 0, 12, 5, 4093},
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{ 0, 18, 5,262141}, { 0, 23, 5,8388605},
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{ 0, 5, 5, 29}, { 0, 8, 4, 253},
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{ 0, 14, 5,16381}, { 0, 20, 5,1048573},
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{ 0, 2, 5, 1}, { 16, 7, 4, 125},
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{ 0, 11, 5, 2045}, { 0, 17, 5,131069},
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{ 0, 22, 5,4194301}, { 0, 4, 5, 13},
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{ 16, 8, 4, 253}, { 0, 13, 5, 8189},
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{ 0, 19, 5,524285}, { 0, 1, 5, 1},
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{ 16, 6, 4, 61}, { 0, 10, 5, 1021},
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{ 0, 16, 5,65533}, { 0, 28, 5,268435453},
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{ 0, 27, 5,134217725}, { 0, 26, 5,67108861},
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{ 0, 25, 5,33554429}, { 0, 24, 5,16777213},
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}; /* OF_defaultDTable */
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/* Default FSE distribution table for Match Lengths */
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static const ZSTD_seqSymbol ML_defaultDTable[(1<<ML_DEFAULTNORMLOG)+1] = {
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{ 1, 1, 1, ML_DEFAULTNORMLOG}, /* header : fastMode, tableLog */
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/* nextState, nbAddBits, nbBits, baseVal */
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{ 0, 0, 6, 3}, { 0, 0, 4, 4},
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{ 32, 0, 5, 5}, { 0, 0, 5, 6},
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{ 0, 0, 5, 8}, { 0, 0, 5, 9},
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{ 0, 0, 5, 11}, { 0, 0, 6, 13},
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{ 0, 0, 6, 16}, { 0, 0, 6, 19},
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{ 0, 0, 6, 22}, { 0, 0, 6, 25},
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{ 0, 0, 6, 28}, { 0, 0, 6, 31},
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{ 0, 0, 6, 34}, { 0, 1, 6, 37},
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{ 0, 1, 6, 41}, { 0, 2, 6, 47},
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{ 0, 3, 6, 59}, { 0, 4, 6, 83},
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{ 0, 7, 6, 131}, { 0, 9, 6, 515},
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{ 16, 0, 4, 4}, { 0, 0, 4, 5},
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{ 32, 0, 5, 6}, { 0, 0, 5, 7},
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{ 32, 0, 5, 9}, { 0, 0, 5, 10},
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{ 0, 0, 6, 12}, { 0, 0, 6, 15},
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{ 0, 0, 6, 18}, { 0, 0, 6, 21},
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{ 0, 0, 6, 24}, { 0, 0, 6, 27},
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{ 0, 0, 6, 30}, { 0, 0, 6, 33},
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{ 0, 1, 6, 35}, { 0, 1, 6, 39},
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{ 0, 2, 6, 43}, { 0, 3, 6, 51},
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{ 0, 4, 6, 67}, { 0, 5, 6, 99},
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{ 0, 8, 6, 259}, { 32, 0, 4, 4},
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{ 48, 0, 4, 4}, { 16, 0, 4, 5},
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{ 32, 0, 5, 7}, { 32, 0, 5, 8},
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{ 32, 0, 5, 10}, { 32, 0, 5, 11},
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{ 0, 0, 6, 14}, { 0, 0, 6, 17},
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{ 0, 0, 6, 20}, { 0, 0, 6, 23},
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{ 0, 0, 6, 26}, { 0, 0, 6, 29},
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{ 0, 0, 6, 32}, { 0, 16, 6,65539},
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{ 0, 15, 6,32771}, { 0, 14, 6,16387},
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{ 0, 13, 6, 8195}, { 0, 12, 6, 4099},
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{ 0, 11, 6, 2051}, { 0, 10, 6, 1027},
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}; /* ML_defaultDTable */
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static void ZSTD_buildSeqTable_rle(ZSTD_seqSymbol* dt, U32 baseValue, U32 nbAddBits)
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{
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void* ptr = dt;
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ZSTD_seqSymbol_header* const DTableH = (ZSTD_seqSymbol_header*)ptr;
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ZSTD_seqSymbol* const cell = dt + 1;
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DTableH->tableLog = 0;
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DTableH->fastMode = 0;
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cell->nbBits = 0;
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cell->nextState = 0;
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assert(nbAddBits < 255);
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cell->nbAdditionalBits = (BYTE)nbAddBits;
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cell->baseValue = baseValue;
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}
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/* ZSTD_buildFSETable() :
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* generate FSE decoding table for one symbol (ll, ml or off)
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* cannot fail if input is valid =>
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* all inputs are presumed validated at this stage */
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FORCE_INLINE_TEMPLATE
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void ZSTD_buildFSETable_body(ZSTD_seqSymbol* dt,
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const short* normalizedCounter, unsigned maxSymbolValue,
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const U32* baseValue, const U32* nbAdditionalBits,
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unsigned tableLog, void* wksp, size_t wkspSize)
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{
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ZSTD_seqSymbol* const tableDecode = dt+1;
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U32 const maxSV1 = maxSymbolValue + 1;
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U32 const tableSize = 1 << tableLog;
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U16* symbolNext = (U16*)wksp;
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BYTE* spread = (BYTE*)(symbolNext + MaxSeq + 1);
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U32 highThreshold = tableSize - 1;
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/* Sanity Checks */
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assert(maxSymbolValue <= MaxSeq);
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assert(tableLog <= MaxFSELog);
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assert(wkspSize >= ZSTD_BUILD_FSE_TABLE_WKSP_SIZE);
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(void)wkspSize;
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/* Init, lay down lowprob symbols */
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{ ZSTD_seqSymbol_header DTableH;
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DTableH.tableLog = tableLog;
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DTableH.fastMode = 1;
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{ S16 const largeLimit= (S16)(1 << (tableLog-1));
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U32 s;
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for (s=0; s<maxSV1; s++) {
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if (normalizedCounter[s]==-1) {
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tableDecode[highThreshold--].baseValue = s;
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symbolNext[s] = 1;
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} else {
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if (normalizedCounter[s] >= largeLimit) DTableH.fastMode=0;
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assert(normalizedCounter[s]>=0);
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symbolNext[s] = (U16)normalizedCounter[s];
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} } }
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ZSTD_memcpy(dt, &DTableH, sizeof(DTableH));
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}
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/* Spread symbols */
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assert(tableSize <= 512);
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/* Specialized symbol spreading for the case when there are
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* no low probability (-1 count) symbols. When compressing
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* small blocks we avoid low probability symbols to hit this
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* case, since header decoding speed matters more.
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*/
|
|
if (highThreshold == tableSize - 1) {
|
|
size_t const tableMask = tableSize-1;
|
|
size_t const step = FSE_TABLESTEP(tableSize);
|
|
/* First lay down the symbols in order.
|
|
* We use a uint64_t to lay down 8 bytes at a time. This reduces branch
|
|
* misses since small blocks generally have small table logs, so nearly
|
|
* all symbols have counts <= 8. We ensure we have 8 bytes at the end of
|
|
* our buffer to handle the over-write.
|
|
*/
|
|
{
|
|
U64 const add = 0x0101010101010101ull;
|
|
size_t pos = 0;
|
|
U64 sv = 0;
|
|
U32 s;
|
|
for (s=0; s<maxSV1; ++s, sv += add) {
|
|
int i;
|
|
int const n = normalizedCounter[s];
|
|
MEM_write64(spread + pos, sv);
|
|
for (i = 8; i < n; i += 8) {
|
|
MEM_write64(spread + pos + i, sv);
|
|
}
|
|
pos += n;
|
|
}
|
|
}
|
|
/* Now we spread those positions across the table.
|
|
* The benefit of doing it in two stages is that we avoid the the
|
|
* variable size inner loop, which caused lots of branch misses.
|
|
* Now we can run through all the positions without any branch misses.
|
|
* We unroll the loop twice, since that is what emperically worked best.
|
|
*/
|
|
{
|
|
size_t position = 0;
|
|
size_t s;
|
|
size_t const unroll = 2;
|
|
assert(tableSize % unroll == 0); /* FSE_MIN_TABLELOG is 5 */
|
|
for (s = 0; s < (size_t)tableSize; s += unroll) {
|
|
size_t u;
|
|
for (u = 0; u < unroll; ++u) {
|
|
size_t const uPosition = (position + (u * step)) & tableMask;
|
|
tableDecode[uPosition].baseValue = spread[s + u];
|
|
}
|
|
position = (position + (unroll * step)) & tableMask;
|
|
}
|
|
assert(position == 0);
|
|
}
|
|
} else {
|
|
U32 const tableMask = tableSize-1;
|
|
U32 const step = FSE_TABLESTEP(tableSize);
|
|
U32 s, position = 0;
|
|
for (s=0; s<maxSV1; s++) {
|
|
int i;
|
|
int const n = normalizedCounter[s];
|
|
for (i=0; i<n; i++) {
|
|
tableDecode[position].baseValue = s;
|
|
position = (position + step) & tableMask;
|
|
while (position > highThreshold) position = (position + step) & tableMask; /* lowprob area */
|
|
} }
|
|
assert(position == 0); /* position must reach all cells once, otherwise normalizedCounter is incorrect */
|
|
}
|
|
|
|
/* Build Decoding table */
|
|
{
|
|
U32 u;
|
|
for (u=0; u<tableSize; u++) {
|
|
U32 const symbol = tableDecode[u].baseValue;
|
|
U32 const nextState = symbolNext[symbol]++;
|
|
tableDecode[u].nbBits = (BYTE) (tableLog - BIT_highbit32(nextState) );
|
|
tableDecode[u].nextState = (U16) ( (nextState << tableDecode[u].nbBits) - tableSize);
|
|
assert(nbAdditionalBits[symbol] < 255);
|
|
tableDecode[u].nbAdditionalBits = (BYTE)nbAdditionalBits[symbol];
|
|
tableDecode[u].baseValue = baseValue[symbol];
|
|
}
|
|
}
|
|
}
|
|
|
|
/* Avoids the FORCE_INLINE of the _body() function. */
|
|
static void ZSTD_buildFSETable_body_default(ZSTD_seqSymbol* dt,
|
|
const short* normalizedCounter, unsigned maxSymbolValue,
|
|
const U32* baseValue, const U32* nbAdditionalBits,
|
|
unsigned tableLog, void* wksp, size_t wkspSize)
|
|
{
|
|
ZSTD_buildFSETable_body(dt, normalizedCounter, maxSymbolValue,
|
|
baseValue, nbAdditionalBits, tableLog, wksp, wkspSize);
|
|
}
|
|
|
|
#if DYNAMIC_BMI2
|
|
TARGET_ATTRIBUTE("bmi2") static void ZSTD_buildFSETable_body_bmi2(ZSTD_seqSymbol* dt,
|
|
const short* normalizedCounter, unsigned maxSymbolValue,
|
|
const U32* baseValue, const U32* nbAdditionalBits,
|
|
unsigned tableLog, void* wksp, size_t wkspSize)
|
|
{
|
|
ZSTD_buildFSETable_body(dt, normalizedCounter, maxSymbolValue,
|
|
baseValue, nbAdditionalBits, tableLog, wksp, wkspSize);
|
|
}
|
|
#endif
|
|
|
|
void ZSTD_buildFSETable(ZSTD_seqSymbol* dt,
|
|
const short* normalizedCounter, unsigned maxSymbolValue,
|
|
const U32* baseValue, const U32* nbAdditionalBits,
|
|
unsigned tableLog, void* wksp, size_t wkspSize, int bmi2)
|
|
{
|
|
#if DYNAMIC_BMI2
|
|
if (bmi2) {
|
|
ZSTD_buildFSETable_body_bmi2(dt, normalizedCounter, maxSymbolValue,
|
|
baseValue, nbAdditionalBits, tableLog, wksp, wkspSize);
|
|
return;
|
|
}
|
|
#endif
|
|
(void)bmi2;
|
|
ZSTD_buildFSETable_body_default(dt, normalizedCounter, maxSymbolValue,
|
|
baseValue, nbAdditionalBits, tableLog, wksp, wkspSize);
|
|
}
|
|
|
|
|
|
/*! ZSTD_buildSeqTable() :
|
|
* @return : nb bytes read from src,
|
|
* or an error code if it fails */
|
|
static size_t ZSTD_buildSeqTable(ZSTD_seqSymbol* DTableSpace, const ZSTD_seqSymbol** DTablePtr,
|
|
symbolEncodingType_e type, unsigned max, U32 maxLog,
|
|
const void* src, size_t srcSize,
|
|
const U32* baseValue, const U32* nbAdditionalBits,
|
|
const ZSTD_seqSymbol* defaultTable, U32 flagRepeatTable,
|
|
int ddictIsCold, int nbSeq, U32* wksp, size_t wkspSize,
|
|
int bmi2)
|
|
{
|
|
switch(type)
|
|
{
|
|
case set_rle :
|
|
RETURN_ERROR_IF(!srcSize, srcSize_wrong, "");
|
|
RETURN_ERROR_IF((*(const BYTE*)src) > max, corruption_detected, "");
|
|
{ U32 const symbol = *(const BYTE*)src;
|
|
U32 const baseline = baseValue[symbol];
|
|
U32 const nbBits = nbAdditionalBits[symbol];
|
|
ZSTD_buildSeqTable_rle(DTableSpace, baseline, nbBits);
|
|
}
|
|
*DTablePtr = DTableSpace;
|
|
return 1;
|
|
case set_basic :
|
|
*DTablePtr = defaultTable;
|
|
return 0;
|
|
case set_repeat:
|
|
RETURN_ERROR_IF(!flagRepeatTable, corruption_detected, "");
|
|
/* prefetch FSE table if used */
|
|
if (ddictIsCold && (nbSeq > 24 /* heuristic */)) {
|
|
const void* const pStart = *DTablePtr;
|
|
size_t const pSize = sizeof(ZSTD_seqSymbol) * (SEQSYMBOL_TABLE_SIZE(maxLog));
|
|
PREFETCH_AREA(pStart, pSize);
|
|
}
|
|
return 0;
|
|
case set_compressed :
|
|
{ unsigned tableLog;
|
|
S16 norm[MaxSeq+1];
|
|
size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize);
|
|
RETURN_ERROR_IF(FSE_isError(headerSize), corruption_detected, "");
|
|
RETURN_ERROR_IF(tableLog > maxLog, corruption_detected, "");
|
|
ZSTD_buildFSETable(DTableSpace, norm, max, baseValue, nbAdditionalBits, tableLog, wksp, wkspSize, bmi2);
|
|
*DTablePtr = DTableSpace;
|
|
return headerSize;
|
|
}
|
|
default :
|
|
assert(0);
|
|
RETURN_ERROR(GENERIC, "impossible");
|
|
}
|
|
}
|
|
|
|
size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx* dctx, int* nbSeqPtr,
|
|
const void* src, size_t srcSize)
|
|
{
|
|
const BYTE* const istart = (const BYTE*)src;
|
|
const BYTE* const iend = istart + srcSize;
|
|
const BYTE* ip = istart;
|
|
int nbSeq;
|
|
DEBUGLOG(5, "ZSTD_decodeSeqHeaders");
|
|
|
|
/* check */
|
|
RETURN_ERROR_IF(srcSize < MIN_SEQUENCES_SIZE, srcSize_wrong, "");
|
|
|
|
/* SeqHead */
|
|
nbSeq = *ip++;
|
|
if (!nbSeq) {
|
|
*nbSeqPtr=0;
|
|
RETURN_ERROR_IF(srcSize != 1, srcSize_wrong, "");
|
|
return 1;
|
|
}
|
|
if (nbSeq > 0x7F) {
|
|
if (nbSeq == 0xFF) {
|
|
RETURN_ERROR_IF(ip+2 > iend, srcSize_wrong, "");
|
|
nbSeq = MEM_readLE16(ip) + LONGNBSEQ;
|
|
ip+=2;
|
|
} else {
|
|
RETURN_ERROR_IF(ip >= iend, srcSize_wrong, "");
|
|
nbSeq = ((nbSeq-0x80)<<8) + *ip++;
|
|
}
|
|
}
|
|
*nbSeqPtr = nbSeq;
|
|
|
|
/* FSE table descriptors */
|
|
RETURN_ERROR_IF(ip+1 > iend, srcSize_wrong, ""); /* minimum possible size: 1 byte for symbol encoding types */
|
|
{ symbolEncodingType_e const LLtype = (symbolEncodingType_e)(*ip >> 6);
|
|
symbolEncodingType_e const OFtype = (symbolEncodingType_e)((*ip >> 4) & 3);
|
|
symbolEncodingType_e const MLtype = (symbolEncodingType_e)((*ip >> 2) & 3);
|
|
ip++;
|
|
|
|
/* Build DTables */
|
|
{ size_t const llhSize = ZSTD_buildSeqTable(dctx->entropy.LLTable, &dctx->LLTptr,
|
|
LLtype, MaxLL, LLFSELog,
|
|
ip, iend-ip,
|
|
LL_base, LL_bits,
|
|
LL_defaultDTable, dctx->fseEntropy,
|
|
dctx->ddictIsCold, nbSeq,
|
|
dctx->workspace, sizeof(dctx->workspace),
|
|
dctx->bmi2);
|
|
RETURN_ERROR_IF(ZSTD_isError(llhSize), corruption_detected, "ZSTD_buildSeqTable failed");
|
|
ip += llhSize;
|
|
}
|
|
|
|
{ size_t const ofhSize = ZSTD_buildSeqTable(dctx->entropy.OFTable, &dctx->OFTptr,
|
|
OFtype, MaxOff, OffFSELog,
|
|
ip, iend-ip,
|
|
OF_base, OF_bits,
|
|
OF_defaultDTable, dctx->fseEntropy,
|
|
dctx->ddictIsCold, nbSeq,
|
|
dctx->workspace, sizeof(dctx->workspace),
|
|
dctx->bmi2);
|
|
RETURN_ERROR_IF(ZSTD_isError(ofhSize), corruption_detected, "ZSTD_buildSeqTable failed");
|
|
ip += ofhSize;
|
|
}
|
|
|
|
{ size_t const mlhSize = ZSTD_buildSeqTable(dctx->entropy.MLTable, &dctx->MLTptr,
|
|
MLtype, MaxML, MLFSELog,
|
|
ip, iend-ip,
|
|
ML_base, ML_bits,
|
|
ML_defaultDTable, dctx->fseEntropy,
|
|
dctx->ddictIsCold, nbSeq,
|
|
dctx->workspace, sizeof(dctx->workspace),
|
|
dctx->bmi2);
|
|
RETURN_ERROR_IF(ZSTD_isError(mlhSize), corruption_detected, "ZSTD_buildSeqTable failed");
|
|
ip += mlhSize;
|
|
}
|
|
}
|
|
|
|
return ip-istart;
|
|
}
|
|
|
|
|
|
typedef struct {
|
|
size_t litLength;
|
|
size_t matchLength;
|
|
size_t offset;
|
|
const BYTE* match;
|
|
} seq_t;
|
|
|
|
typedef struct {
|
|
size_t state;
|
|
const ZSTD_seqSymbol* table;
|
|
} ZSTD_fseState;
|
|
|
|
typedef struct {
|
|
BIT_DStream_t DStream;
|
|
ZSTD_fseState stateLL;
|
|
ZSTD_fseState stateOffb;
|
|
ZSTD_fseState stateML;
|
|
size_t prevOffset[ZSTD_REP_NUM];
|
|
const BYTE* prefixStart;
|
|
const BYTE* dictEnd;
|
|
size_t pos;
|
|
} seqState_t;
|
|
|
|
/*! ZSTD_overlapCopy8() :
|
|
* Copies 8 bytes from ip to op and updates op and ip where ip <= op.
|
|
* If the offset is < 8 then the offset is spread to at least 8 bytes.
|
|
*
|
|
* Precondition: *ip <= *op
|
|
* Postcondition: *op - *op >= 8
|
|
*/
|
|
HINT_INLINE void ZSTD_overlapCopy8(BYTE** op, BYTE const** ip, size_t offset) {
|
|
assert(*ip <= *op);
|
|
if (offset < 8) {
|
|
/* close range match, overlap */
|
|
static const U32 dec32table[] = { 0, 1, 2, 1, 4, 4, 4, 4 }; /* added */
|
|
static const int dec64table[] = { 8, 8, 8, 7, 8, 9,10,11 }; /* subtracted */
|
|
int const sub2 = dec64table[offset];
|
|
(*op)[0] = (*ip)[0];
|
|
(*op)[1] = (*ip)[1];
|
|
(*op)[2] = (*ip)[2];
|
|
(*op)[3] = (*ip)[3];
|
|
*ip += dec32table[offset];
|
|
ZSTD_copy4(*op+4, *ip);
|
|
*ip -= sub2;
|
|
} else {
|
|
ZSTD_copy8(*op, *ip);
|
|
}
|
|
*ip += 8;
|
|
*op += 8;
|
|
assert(*op - *ip >= 8);
|
|
}
|
|
|
|
/*! ZSTD_safecopy() :
|
|
* Specialized version of memcpy() that is allowed to READ up to WILDCOPY_OVERLENGTH past the input buffer
|
|
* and write up to 16 bytes past oend_w (op >= oend_w is allowed).
|
|
* This function is only called in the uncommon case where the sequence is near the end of the block. It
|
|
* should be fast for a single long sequence, but can be slow for several short sequences.
|
|
*
|
|
* @param ovtype controls the overlap detection
|
|
* - ZSTD_no_overlap: The source and destination are guaranteed to be at least WILDCOPY_VECLEN bytes apart.
|
|
* - ZSTD_overlap_src_before_dst: The src and dst may overlap and may be any distance apart.
|
|
* The src buffer must be before the dst buffer.
|
|
*/
|
|
static void ZSTD_safecopy(BYTE* op, BYTE* const oend_w, BYTE const* ip, ptrdiff_t length, ZSTD_overlap_e ovtype) {
|
|
ptrdiff_t const diff = op - ip;
|
|
BYTE* const oend = op + length;
|
|
|
|
assert((ovtype == ZSTD_no_overlap && (diff <= -8 || diff >= 8 || op >= oend_w)) ||
|
|
(ovtype == ZSTD_overlap_src_before_dst && diff >= 0));
|
|
|
|
if (length < 8) {
|
|
/* Handle short lengths. */
|
|
while (op < oend) *op++ = *ip++;
|
|
return;
|
|
}
|
|
if (ovtype == ZSTD_overlap_src_before_dst) {
|
|
/* Copy 8 bytes and ensure the offset >= 8 when there can be overlap. */
|
|
assert(length >= 8);
|
|
ZSTD_overlapCopy8(&op, &ip, diff);
|
|
assert(op - ip >= 8);
|
|
assert(op <= oend);
|
|
}
|
|
|
|
if (oend <= oend_w) {
|
|
/* No risk of overwrite. */
|
|
ZSTD_wildcopy(op, ip, length, ovtype);
|
|
return;
|
|
}
|
|
if (op <= oend_w) {
|
|
/* Wildcopy until we get close to the end. */
|
|
assert(oend > oend_w);
|
|
ZSTD_wildcopy(op, ip, oend_w - op, ovtype);
|
|
ip += oend_w - op;
|
|
op = oend_w;
|
|
}
|
|
/* Handle the leftovers. */
|
|
while (op < oend) *op++ = *ip++;
|
|
}
|
|
|
|
/* ZSTD_execSequenceEnd():
|
|
* This version handles cases that are near the end of the output buffer. It requires
|
|
* more careful checks to make sure there is no overflow. By separating out these hard
|
|
* and unlikely cases, we can speed up the common cases.
|
|
*
|
|
* NOTE: This function needs to be fast for a single long sequence, but doesn't need
|
|
* to be optimized for many small sequences, since those fall into ZSTD_execSequence().
|
|
*/
|
|
FORCE_NOINLINE
|
|
size_t ZSTD_execSequenceEnd(BYTE* op,
|
|
BYTE* const oend, seq_t sequence,
|
|
const BYTE** litPtr, const BYTE* const litLimit,
|
|
const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd)
|
|
{
|
|
BYTE* const oLitEnd = op + sequence.litLength;
|
|
size_t const sequenceLength = sequence.litLength + sequence.matchLength;
|
|
const BYTE* const iLitEnd = *litPtr + sequence.litLength;
|
|
const BYTE* match = oLitEnd - sequence.offset;
|
|
BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH;
|
|
|
|
/* bounds checks : careful of address space overflow in 32-bit mode */
|
|
RETURN_ERROR_IF(sequenceLength > (size_t)(oend - op), dstSize_tooSmall, "last match must fit within dstBuffer");
|
|
RETURN_ERROR_IF(sequence.litLength > (size_t)(litLimit - *litPtr), corruption_detected, "try to read beyond literal buffer");
|
|
assert(op < op + sequenceLength);
|
|
assert(oLitEnd < op + sequenceLength);
|
|
|
|
/* copy literals */
|
|
ZSTD_safecopy(op, oend_w, *litPtr, sequence.litLength, ZSTD_no_overlap);
|
|
op = oLitEnd;
|
|
*litPtr = iLitEnd;
|
|
|
|
/* copy Match */
|
|
if (sequence.offset > (size_t)(oLitEnd - prefixStart)) {
|
|
/* offset beyond prefix */
|
|
RETURN_ERROR_IF(sequence.offset > (size_t)(oLitEnd - virtualStart), corruption_detected, "");
|
|
match = dictEnd - (prefixStart-match);
|
|
if (match + sequence.matchLength <= dictEnd) {
|
|
ZSTD_memmove(oLitEnd, match, sequence.matchLength);
|
|
return sequenceLength;
|
|
}
|
|
/* span extDict & currentPrefixSegment */
|
|
{ size_t const length1 = dictEnd - match;
|
|
ZSTD_memmove(oLitEnd, match, length1);
|
|
op = oLitEnd + length1;
|
|
sequence.matchLength -= length1;
|
|
match = prefixStart;
|
|
} }
|
|
ZSTD_safecopy(op, oend_w, match, sequence.matchLength, ZSTD_overlap_src_before_dst);
|
|
return sequenceLength;
|
|
}
|
|
|
|
HINT_INLINE
|
|
size_t ZSTD_execSequence(BYTE* op,
|
|
BYTE* const oend, seq_t sequence,
|
|
const BYTE** litPtr, const BYTE* const litLimit,
|
|
const BYTE* const prefixStart, const BYTE* const virtualStart, const BYTE* const dictEnd)
|
|
{
|
|
BYTE* const oLitEnd = op + sequence.litLength;
|
|
size_t const sequenceLength = sequence.litLength + sequence.matchLength;
|
|
BYTE* const oMatchEnd = op + sequenceLength; /* risk : address space overflow (32-bits) */
|
|
BYTE* const oend_w = oend - WILDCOPY_OVERLENGTH; /* risk : address space underflow on oend=NULL */
|
|
const BYTE* const iLitEnd = *litPtr + sequence.litLength;
|
|
const BYTE* match = oLitEnd - sequence.offset;
|
|
|
|
assert(op != NULL /* Precondition */);
|
|
assert(oend_w < oend /* No underflow */);
|
|
/* Handle edge cases in a slow path:
|
|
* - Read beyond end of literals
|
|
* - Match end is within WILDCOPY_OVERLIMIT of oend
|
|
* - 32-bit mode and the match length overflows
|
|
*/
|
|
if (UNLIKELY(
|
|
iLitEnd > litLimit ||
|
|
oMatchEnd > oend_w ||
|
|
(MEM_32bits() && (size_t)(oend - op) < sequenceLength + WILDCOPY_OVERLENGTH)))
|
|
return ZSTD_execSequenceEnd(op, oend, sequence, litPtr, litLimit, prefixStart, virtualStart, dictEnd);
|
|
|
|
/* Assumptions (everything else goes into ZSTD_execSequenceEnd()) */
|
|
assert(op <= oLitEnd /* No overflow */);
|
|
assert(oLitEnd < oMatchEnd /* Non-zero match & no overflow */);
|
|
assert(oMatchEnd <= oend /* No underflow */);
|
|
assert(iLitEnd <= litLimit /* Literal length is in bounds */);
|
|
assert(oLitEnd <= oend_w /* Can wildcopy literals */);
|
|
assert(oMatchEnd <= oend_w /* Can wildcopy matches */);
|
|
|
|
/* Copy Literals:
|
|
* Split out litLength <= 16 since it is nearly always true. +1.6% on gcc-9.
|
|
* We likely don't need the full 32-byte wildcopy.
|
|
*/
|
|
assert(WILDCOPY_OVERLENGTH >= 16);
|
|
ZSTD_copy16(op, (*litPtr));
|
|
if (UNLIKELY(sequence.litLength > 16)) {
|
|
ZSTD_wildcopy(op+16, (*litPtr)+16, sequence.litLength-16, ZSTD_no_overlap);
|
|
}
|
|
op = oLitEnd;
|
|
*litPtr = iLitEnd; /* update for next sequence */
|
|
|
|
/* Copy Match */
|
|
if (sequence.offset > (size_t)(oLitEnd - prefixStart)) {
|
|
/* offset beyond prefix -> go into extDict */
|
|
RETURN_ERROR_IF(UNLIKELY(sequence.offset > (size_t)(oLitEnd - virtualStart)), corruption_detected, "");
|
|
match = dictEnd + (match - prefixStart);
|
|
if (match + sequence.matchLength <= dictEnd) {
|
|
ZSTD_memmove(oLitEnd, match, sequence.matchLength);
|
|
return sequenceLength;
|
|
}
|
|
/* span extDict & currentPrefixSegment */
|
|
{ size_t const length1 = dictEnd - match;
|
|
ZSTD_memmove(oLitEnd, match, length1);
|
|
op = oLitEnd + length1;
|
|
sequence.matchLength -= length1;
|
|
match = prefixStart;
|
|
} }
|
|
/* Match within prefix of 1 or more bytes */
|
|
assert(op <= oMatchEnd);
|
|
assert(oMatchEnd <= oend_w);
|
|
assert(match >= prefixStart);
|
|
assert(sequence.matchLength >= 1);
|
|
|
|
/* Nearly all offsets are >= WILDCOPY_VECLEN bytes, which means we can use wildcopy
|
|
* without overlap checking.
|
|
*/
|
|
if (LIKELY(sequence.offset >= WILDCOPY_VECLEN)) {
|
|
/* We bet on a full wildcopy for matches, since we expect matches to be
|
|
* longer than literals (in general). In silesia, ~10% of matches are longer
|
|
* than 16 bytes.
|
|
*/
|
|
ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength, ZSTD_no_overlap);
|
|
return sequenceLength;
|
|
}
|
|
assert(sequence.offset < WILDCOPY_VECLEN);
|
|
|
|
/* Copy 8 bytes and spread the offset to be >= 8. */
|
|
ZSTD_overlapCopy8(&op, &match, sequence.offset);
|
|
|
|
/* If the match length is > 8 bytes, then continue with the wildcopy. */
|
|
if (sequence.matchLength > 8) {
|
|
assert(op < oMatchEnd);
|
|
ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8, ZSTD_overlap_src_before_dst);
|
|
}
|
|
return sequenceLength;
|
|
}
|
|
|
|
static void
|
|
ZSTD_initFseState(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, const ZSTD_seqSymbol* dt)
|
|
{
|
|
const void* ptr = dt;
|
|
const ZSTD_seqSymbol_header* const DTableH = (const ZSTD_seqSymbol_header*)ptr;
|
|
DStatePtr->state = BIT_readBits(bitD, DTableH->tableLog);
|
|
DEBUGLOG(6, "ZSTD_initFseState : val=%u using %u bits",
|
|
(U32)DStatePtr->state, DTableH->tableLog);
|
|
BIT_reloadDStream(bitD);
|
|
DStatePtr->table = dt + 1;
|
|
}
|
|
|
|
FORCE_INLINE_TEMPLATE void
|
|
ZSTD_updateFseState(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD)
|
|
{
|
|
ZSTD_seqSymbol const DInfo = DStatePtr->table[DStatePtr->state];
|
|
U32 const nbBits = DInfo.nbBits;
|
|
size_t const lowBits = BIT_readBits(bitD, nbBits);
|
|
DStatePtr->state = DInfo.nextState + lowBits;
|
|
}
|
|
|
|
FORCE_INLINE_TEMPLATE void
|
|
ZSTD_updateFseStateWithDInfo(ZSTD_fseState* DStatePtr, BIT_DStream_t* bitD, ZSTD_seqSymbol const DInfo)
|
|
{
|
|
U32 const nbBits = DInfo.nbBits;
|
|
size_t const lowBits = BIT_readBits(bitD, nbBits);
|
|
DStatePtr->state = DInfo.nextState + lowBits;
|
|
}
|
|
|
|
/* We need to add at most (ZSTD_WINDOWLOG_MAX_32 - 1) bits to read the maximum
|
|
* offset bits. But we can only read at most (STREAM_ACCUMULATOR_MIN_32 - 1)
|
|
* bits before reloading. This value is the maximum number of bytes we read
|
|
* after reloading when we are decoding long offsets.
|
|
*/
|
|
#define LONG_OFFSETS_MAX_EXTRA_BITS_32 \
|
|
(ZSTD_WINDOWLOG_MAX_32 > STREAM_ACCUMULATOR_MIN_32 \
|
|
? ZSTD_WINDOWLOG_MAX_32 - STREAM_ACCUMULATOR_MIN_32 \
|
|
: 0)
|
|
|
|
typedef enum { ZSTD_lo_isRegularOffset, ZSTD_lo_isLongOffset=1 } ZSTD_longOffset_e;
|
|
typedef enum { ZSTD_p_noPrefetch=0, ZSTD_p_prefetch=1 } ZSTD_prefetch_e;
|
|
|
|
FORCE_INLINE_TEMPLATE seq_t
|
|
ZSTD_decodeSequence(seqState_t* seqState, const ZSTD_longOffset_e longOffsets, const ZSTD_prefetch_e prefetch)
|
|
{
|
|
seq_t seq;
|
|
ZSTD_seqSymbol const llDInfo = seqState->stateLL.table[seqState->stateLL.state];
|
|
ZSTD_seqSymbol const mlDInfo = seqState->stateML.table[seqState->stateML.state];
|
|
ZSTD_seqSymbol const ofDInfo = seqState->stateOffb.table[seqState->stateOffb.state];
|
|
U32 const llBase = llDInfo.baseValue;
|
|
U32 const mlBase = mlDInfo.baseValue;
|
|
U32 const ofBase = ofDInfo.baseValue;
|
|
BYTE const llBits = llDInfo.nbAdditionalBits;
|
|
BYTE const mlBits = mlDInfo.nbAdditionalBits;
|
|
BYTE const ofBits = ofDInfo.nbAdditionalBits;
|
|
BYTE const totalBits = llBits+mlBits+ofBits;
|
|
|
|
/* sequence */
|
|
{ size_t offset;
|
|
if (ofBits > 1) {
|
|
ZSTD_STATIC_ASSERT(ZSTD_lo_isLongOffset == 1);
|
|
ZSTD_STATIC_ASSERT(LONG_OFFSETS_MAX_EXTRA_BITS_32 == 5);
|
|
assert(ofBits <= MaxOff);
|
|
if (MEM_32bits() && longOffsets && (ofBits >= STREAM_ACCUMULATOR_MIN_32)) {
|
|
U32 const extraBits = ofBits - MIN(ofBits, 32 - seqState->DStream.bitsConsumed);
|
|
offset = ofBase + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
|
|
BIT_reloadDStream(&seqState->DStream);
|
|
if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits);
|
|
assert(extraBits <= LONG_OFFSETS_MAX_EXTRA_BITS_32); /* to avoid another reload */
|
|
} else {
|
|
offset = ofBase + BIT_readBitsFast(&seqState->DStream, ofBits/*>0*/); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */
|
|
if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream);
|
|
}
|
|
seqState->prevOffset[2] = seqState->prevOffset[1];
|
|
seqState->prevOffset[1] = seqState->prevOffset[0];
|
|
seqState->prevOffset[0] = offset;
|
|
} else {
|
|
U32 const ll0 = (llBase == 0);
|
|
if (LIKELY((ofBits == 0))) {
|
|
if (LIKELY(!ll0))
|
|
offset = seqState->prevOffset[0];
|
|
else {
|
|
offset = seqState->prevOffset[1];
|
|
seqState->prevOffset[1] = seqState->prevOffset[0];
|
|
seqState->prevOffset[0] = offset;
|
|
}
|
|
} else {
|
|
offset = ofBase + ll0 + BIT_readBitsFast(&seqState->DStream, 1);
|
|
{ size_t temp = (offset==3) ? seqState->prevOffset[0] - 1 : seqState->prevOffset[offset];
|
|
temp += !temp; /* 0 is not valid; input is corrupted; force offset to 1 */
|
|
if (offset != 1) seqState->prevOffset[2] = seqState->prevOffset[1];
|
|
seqState->prevOffset[1] = seqState->prevOffset[0];
|
|
seqState->prevOffset[0] = offset = temp;
|
|
} } }
|
|
seq.offset = offset;
|
|
}
|
|
|
|
seq.matchLength = mlBase;
|
|
if (mlBits > 0)
|
|
seq.matchLength += BIT_readBitsFast(&seqState->DStream, mlBits/*>0*/);
|
|
|
|
if (MEM_32bits() && (mlBits+llBits >= STREAM_ACCUMULATOR_MIN_32-LONG_OFFSETS_MAX_EXTRA_BITS_32))
|
|
BIT_reloadDStream(&seqState->DStream);
|
|
if (MEM_64bits() && UNLIKELY(totalBits >= STREAM_ACCUMULATOR_MIN_64-(LLFSELog+MLFSELog+OffFSELog)))
|
|
BIT_reloadDStream(&seqState->DStream);
|
|
/* Ensure there are enough bits to read the rest of data in 64-bit mode. */
|
|
ZSTD_STATIC_ASSERT(16+LLFSELog+MLFSELog+OffFSELog < STREAM_ACCUMULATOR_MIN_64);
|
|
|
|
seq.litLength = llBase;
|
|
if (llBits > 0)
|
|
seq.litLength += BIT_readBitsFast(&seqState->DStream, llBits/*>0*/);
|
|
|
|
if (MEM_32bits())
|
|
BIT_reloadDStream(&seqState->DStream);
|
|
|
|
DEBUGLOG(6, "seq: litL=%u, matchL=%u, offset=%u",
|
|
(U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset);
|
|
|
|
if (prefetch == ZSTD_p_prefetch) {
|
|
size_t const pos = seqState->pos + seq.litLength;
|
|
const BYTE* const matchBase = (seq.offset > pos) ? seqState->dictEnd : seqState->prefixStart;
|
|
seq.match = matchBase + pos - seq.offset; /* note : this operation can overflow when seq.offset is really too large, which can only happen when input is corrupted.
|
|
* No consequence though : no memory access will occur, offset is only used for prefetching */
|
|
seqState->pos = pos + seq.matchLength;
|
|
}
|
|
|
|
/* ANS state update
|
|
* gcc-9.0.0 does 2.5% worse with ZSTD_updateFseStateWithDInfo().
|
|
* clang-9.2.0 does 7% worse with ZSTD_updateFseState().
|
|
* Naturally it seems like ZSTD_updateFseStateWithDInfo() should be the
|
|
* better option, so it is the default for other compilers. But, if you
|
|
* measure that it is worse, please put up a pull request.
|
|
*/
|
|
{
|
|
#if !defined(__clang__)
|
|
const int kUseUpdateFseState = 1;
|
|
#else
|
|
const int kUseUpdateFseState = 0;
|
|
#endif
|
|
if (kUseUpdateFseState) {
|
|
ZSTD_updateFseState(&seqState->stateLL, &seqState->DStream); /* <= 9 bits */
|
|
ZSTD_updateFseState(&seqState->stateML, &seqState->DStream); /* <= 9 bits */
|
|
if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
|
|
ZSTD_updateFseState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */
|
|
} else {
|
|
ZSTD_updateFseStateWithDInfo(&seqState->stateLL, &seqState->DStream, llDInfo); /* <= 9 bits */
|
|
ZSTD_updateFseStateWithDInfo(&seqState->stateML, &seqState->DStream, mlDInfo); /* <= 9 bits */
|
|
if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
|
|
ZSTD_updateFseStateWithDInfo(&seqState->stateOffb, &seqState->DStream, ofDInfo); /* <= 8 bits */
|
|
}
|
|
}
|
|
|
|
return seq;
|
|
}
|
|
|
|
#ifdef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
|
|
MEM_STATIC int ZSTD_dictionaryIsActive(ZSTD_DCtx const* dctx, BYTE const* prefixStart, BYTE const* oLitEnd)
|
|
{
|
|
size_t const windowSize = dctx->fParams.windowSize;
|
|
/* No dictionary used. */
|
|
if (dctx->dictContentEndForFuzzing == NULL) return 0;
|
|
/* Dictionary is our prefix. */
|
|
if (prefixStart == dctx->dictContentBeginForFuzzing) return 1;
|
|
/* Dictionary is not our ext-dict. */
|
|
if (dctx->dictEnd != dctx->dictContentEndForFuzzing) return 0;
|
|
/* Dictionary is not within our window size. */
|
|
if ((size_t)(oLitEnd - prefixStart) >= windowSize) return 0;
|
|
/* Dictionary is active. */
|
|
return 1;
|
|
}
|
|
|
|
MEM_STATIC void ZSTD_assertValidSequence(
|
|
ZSTD_DCtx const* dctx,
|
|
BYTE const* op, BYTE const* oend,
|
|
seq_t const seq,
|
|
BYTE const* prefixStart, BYTE const* virtualStart)
|
|
{
|
|
#if DEBUGLEVEL >= 1
|
|
size_t const windowSize = dctx->fParams.windowSize;
|
|
size_t const sequenceSize = seq.litLength + seq.matchLength;
|
|
BYTE const* const oLitEnd = op + seq.litLength;
|
|
DEBUGLOG(6, "Checking sequence: litL=%u matchL=%u offset=%u",
|
|
(U32)seq.litLength, (U32)seq.matchLength, (U32)seq.offset);
|
|
assert(op <= oend);
|
|
assert((size_t)(oend - op) >= sequenceSize);
|
|
assert(sequenceSize <= ZSTD_BLOCKSIZE_MAX);
|
|
if (ZSTD_dictionaryIsActive(dctx, prefixStart, oLitEnd)) {
|
|
size_t const dictSize = (size_t)((char const*)dctx->dictContentEndForFuzzing - (char const*)dctx->dictContentBeginForFuzzing);
|
|
/* Offset must be within the dictionary. */
|
|
assert(seq.offset <= (size_t)(oLitEnd - virtualStart));
|
|
assert(seq.offset <= windowSize + dictSize);
|
|
} else {
|
|
/* Offset must be within our window. */
|
|
assert(seq.offset <= windowSize);
|
|
}
|
|
#else
|
|
(void)dctx, (void)op, (void)oend, (void)seq, (void)prefixStart, (void)virtualStart;
|
|
#endif
|
|
}
|
|
#endif
|
|
|
|
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
|
|
FORCE_INLINE_TEMPLATE size_t
|
|
DONT_VECTORIZE
|
|
ZSTD_decompressSequences_body( ZSTD_DCtx* dctx,
|
|
void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame)
|
|
{
|
|
const BYTE* ip = (const BYTE*)seqStart;
|
|
const BYTE* const iend = ip + seqSize;
|
|
BYTE* const ostart = (BYTE*)dst;
|
|
BYTE* const oend = ostart + maxDstSize;
|
|
BYTE* op = ostart;
|
|
const BYTE* litPtr = dctx->litPtr;
|
|
const BYTE* const litEnd = litPtr + dctx->litSize;
|
|
const BYTE* const prefixStart = (const BYTE*) (dctx->prefixStart);
|
|
const BYTE* const vBase = (const BYTE*) (dctx->virtualStart);
|
|
const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
|
|
DEBUGLOG(5, "ZSTD_decompressSequences_body");
|
|
(void)frame;
|
|
|
|
/* Regen sequences */
|
|
if (nbSeq) {
|
|
seqState_t seqState;
|
|
size_t error = 0;
|
|
dctx->fseEntropy = 1;
|
|
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; }
|
|
RETURN_ERROR_IF(
|
|
ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend-ip)),
|
|
corruption_detected, "");
|
|
ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
|
|
ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
|
|
ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
|
|
assert(dst != NULL);
|
|
|
|
ZSTD_STATIC_ASSERT(
|
|
BIT_DStream_unfinished < BIT_DStream_completed &&
|
|
BIT_DStream_endOfBuffer < BIT_DStream_completed &&
|
|
BIT_DStream_completed < BIT_DStream_overflow);
|
|
|
|
#if defined(__x86_64__)
|
|
/* Align the decompression loop to 32 + 16 bytes.
|
|
*
|
|
* zstd compiled with gcc-9 on an Intel i9-9900k shows 10% decompression
|
|
* speed swings based on the alignment of the decompression loop. This
|
|
* performance swing is caused by parts of the decompression loop falling
|
|
* out of the DSB. The entire decompression loop should fit in the DSB,
|
|
* when it can't we get much worse performance. You can measure if you've
|
|
* hit the good case or the bad case with this perf command for some
|
|
* compressed file test.zst:
|
|
*
|
|
* perf stat -e cycles -e instructions -e idq.all_dsb_cycles_any_uops \
|
|
* -e idq.all_mite_cycles_any_uops -- ./zstd -tq test.zst
|
|
*
|
|
* If you see most cycles served out of the MITE you've hit the bad case.
|
|
* If you see most cycles served out of the DSB you've hit the good case.
|
|
* If it is pretty even then you may be in an okay case.
|
|
*
|
|
* I've been able to reproduce this issue on the following CPUs:
|
|
* - Kabylake: Macbook Pro (15-inch, 2019) 2.4 GHz Intel Core i9
|
|
* Use Instruments->Counters to get DSB/MITE cycles.
|
|
* I never got performance swings, but I was able to
|
|
* go from the good case of mostly DSB to half of the
|
|
* cycles served from MITE.
|
|
* - Coffeelake: Intel i9-9900k
|
|
*
|
|
* I haven't been able to reproduce the instability or DSB misses on any
|
|
* of the following CPUS:
|
|
* - Haswell
|
|
* - Broadwell: Intel(R) Xeon(R) CPU E5-2680 v4 @ 2.40GH
|
|
* - Skylake
|
|
*
|
|
* If you are seeing performance stability this script can help test.
|
|
* It tests on 4 commits in zstd where I saw performance change.
|
|
*
|
|
* https://gist.github.com/terrelln/9889fc06a423fd5ca6e99351564473f4
|
|
*/
|
|
__asm__(".p2align 5");
|
|
__asm__("nop");
|
|
__asm__(".p2align 4");
|
|
#endif
|
|
for ( ; ; ) {
|
|
seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset, ZSTD_p_noPrefetch);
|
|
size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, prefixStart, vBase, dictEnd);
|
|
#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE)
|
|
assert(!ZSTD_isError(oneSeqSize));
|
|
if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequence, prefixStart, vBase);
|
|
#endif
|
|
DEBUGLOG(6, "regenerated sequence size : %u", (U32)oneSeqSize);
|
|
BIT_reloadDStream(&(seqState.DStream));
|
|
op += oneSeqSize;
|
|
/* gcc and clang both don't like early returns in this loop.
|
|
* Instead break and check for an error at the end of the loop.
|
|
*/
|
|
if (UNLIKELY(ZSTD_isError(oneSeqSize))) {
|
|
error = oneSeqSize;
|
|
break;
|
|
}
|
|
if (UNLIKELY(!--nbSeq)) break;
|
|
}
|
|
|
|
/* check if reached exact end */
|
|
DEBUGLOG(5, "ZSTD_decompressSequences_body: after decode loop, remaining nbSeq : %i", nbSeq);
|
|
if (ZSTD_isError(error)) return error;
|
|
RETURN_ERROR_IF(nbSeq, corruption_detected, "");
|
|
RETURN_ERROR_IF(BIT_reloadDStream(&seqState.DStream) < BIT_DStream_completed, corruption_detected, "");
|
|
/* save reps for next block */
|
|
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); }
|
|
}
|
|
|
|
/* last literal segment */
|
|
{ size_t const lastLLSize = litEnd - litPtr;
|
|
RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, "");
|
|
if (op != NULL) {
|
|
ZSTD_memcpy(op, litPtr, lastLLSize);
|
|
op += lastLLSize;
|
|
}
|
|
}
|
|
|
|
return op-ostart;
|
|
}
|
|
|
|
static size_t
|
|
ZSTD_decompressSequences_default(ZSTD_DCtx* dctx,
|
|
void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame)
|
|
{
|
|
return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame);
|
|
}
|
|
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */
|
|
|
|
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
|
|
FORCE_INLINE_TEMPLATE size_t
|
|
ZSTD_decompressSequencesLong_body(
|
|
ZSTD_DCtx* dctx,
|
|
void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame)
|
|
{
|
|
const BYTE* ip = (const BYTE*)seqStart;
|
|
const BYTE* const iend = ip + seqSize;
|
|
BYTE* const ostart = (BYTE*)dst;
|
|
BYTE* const oend = ostart + maxDstSize;
|
|
BYTE* op = ostart;
|
|
const BYTE* litPtr = dctx->litPtr;
|
|
const BYTE* const litEnd = litPtr + dctx->litSize;
|
|
const BYTE* const prefixStart = (const BYTE*) (dctx->prefixStart);
|
|
const BYTE* const dictStart = (const BYTE*) (dctx->virtualStart);
|
|
const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
|
|
(void)frame;
|
|
|
|
/* Regen sequences */
|
|
if (nbSeq) {
|
|
#define STORED_SEQS 4
|
|
#define STORED_SEQS_MASK (STORED_SEQS-1)
|
|
#define ADVANCED_SEQS 4
|
|
seq_t sequences[STORED_SEQS];
|
|
int const seqAdvance = MIN(nbSeq, ADVANCED_SEQS);
|
|
seqState_t seqState;
|
|
int seqNb;
|
|
dctx->fseEntropy = 1;
|
|
{ int i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; }
|
|
seqState.prefixStart = prefixStart;
|
|
seqState.pos = (size_t)(op-prefixStart);
|
|
seqState.dictEnd = dictEnd;
|
|
assert(dst != NULL);
|
|
assert(iend >= ip);
|
|
RETURN_ERROR_IF(
|
|
ERR_isError(BIT_initDStream(&seqState.DStream, ip, iend-ip)),
|
|
corruption_detected, "");
|
|
ZSTD_initFseState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
|
|
ZSTD_initFseState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
|
|
ZSTD_initFseState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
|
|
|
|
/* prepare in advance */
|
|
for (seqNb=0; (BIT_reloadDStream(&seqState.DStream) <= BIT_DStream_completed) && (seqNb<seqAdvance); seqNb++) {
|
|
sequences[seqNb] = ZSTD_decodeSequence(&seqState, isLongOffset, ZSTD_p_prefetch);
|
|
PREFETCH_L1(sequences[seqNb].match); PREFETCH_L1(sequences[seqNb].match + sequences[seqNb].matchLength - 1); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */
|
|
}
|
|
RETURN_ERROR_IF(seqNb<seqAdvance, corruption_detected, "");
|
|
|
|
/* decode and decompress */
|
|
for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && (seqNb<nbSeq) ; seqNb++) {
|
|
seq_t const sequence = ZSTD_decodeSequence(&seqState, isLongOffset, ZSTD_p_prefetch);
|
|
size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequences[(seqNb-ADVANCED_SEQS) & STORED_SEQS_MASK], &litPtr, litEnd, prefixStart, dictStart, dictEnd);
|
|
#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE)
|
|
assert(!ZSTD_isError(oneSeqSize));
|
|
if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[(seqNb-ADVANCED_SEQS) & STORED_SEQS_MASK], prefixStart, dictStart);
|
|
#endif
|
|
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
|
|
PREFETCH_L1(sequence.match); PREFETCH_L1(sequence.match + sequence.matchLength - 1); /* note : it's safe to invoke PREFETCH() on any memory address, including invalid ones */
|
|
sequences[seqNb & STORED_SEQS_MASK] = sequence;
|
|
op += oneSeqSize;
|
|
}
|
|
RETURN_ERROR_IF(seqNb<nbSeq, corruption_detected, "");
|
|
|
|
/* finish queue */
|
|
seqNb -= seqAdvance;
|
|
for ( ; seqNb<nbSeq ; seqNb++) {
|
|
size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequences[seqNb&STORED_SEQS_MASK], &litPtr, litEnd, prefixStart, dictStart, dictEnd);
|
|
#if defined(FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION) && defined(FUZZING_ASSERT_VALID_SEQUENCE)
|
|
assert(!ZSTD_isError(oneSeqSize));
|
|
if (frame) ZSTD_assertValidSequence(dctx, op, oend, sequences[seqNb&STORED_SEQS_MASK], prefixStart, dictStart);
|
|
#endif
|
|
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
|
|
op += oneSeqSize;
|
|
}
|
|
|
|
/* save reps for next block */
|
|
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) dctx->entropy.rep[i] = (U32)(seqState.prevOffset[i]); }
|
|
}
|
|
|
|
/* last literal segment */
|
|
{ size_t const lastLLSize = litEnd - litPtr;
|
|
RETURN_ERROR_IF(lastLLSize > (size_t)(oend-op), dstSize_tooSmall, "");
|
|
if (op != NULL) {
|
|
ZSTD_memcpy(op, litPtr, lastLLSize);
|
|
op += lastLLSize;
|
|
}
|
|
}
|
|
|
|
return op-ostart;
|
|
}
|
|
|
|
static size_t
|
|
ZSTD_decompressSequencesLong_default(ZSTD_DCtx* dctx,
|
|
void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame)
|
|
{
|
|
return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame);
|
|
}
|
|
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */
|
|
|
|
|
|
|
|
#if DYNAMIC_BMI2
|
|
|
|
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
|
|
static TARGET_ATTRIBUTE("bmi2") size_t
|
|
DONT_VECTORIZE
|
|
ZSTD_decompressSequences_bmi2(ZSTD_DCtx* dctx,
|
|
void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame)
|
|
{
|
|
return ZSTD_decompressSequences_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame);
|
|
}
|
|
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */
|
|
|
|
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
|
|
static TARGET_ATTRIBUTE("bmi2") size_t
|
|
ZSTD_decompressSequencesLong_bmi2(ZSTD_DCtx* dctx,
|
|
void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame)
|
|
{
|
|
return ZSTD_decompressSequencesLong_body(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame);
|
|
}
|
|
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */
|
|
|
|
#endif /* DYNAMIC_BMI2 */
|
|
|
|
typedef size_t (*ZSTD_decompressSequences_t)(
|
|
ZSTD_DCtx* dctx,
|
|
void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame);
|
|
|
|
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
|
|
static size_t
|
|
ZSTD_decompressSequences(ZSTD_DCtx* dctx, void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame)
|
|
{
|
|
DEBUGLOG(5, "ZSTD_decompressSequences");
|
|
#if DYNAMIC_BMI2
|
|
if (dctx->bmi2) {
|
|
return ZSTD_decompressSequences_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame);
|
|
}
|
|
#endif
|
|
return ZSTD_decompressSequences_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame);
|
|
}
|
|
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG */
|
|
|
|
|
|
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
|
|
/* ZSTD_decompressSequencesLong() :
|
|
* decompression function triggered when a minimum share of offsets is considered "long",
|
|
* aka out of cache.
|
|
* note : "long" definition seems overloaded here, sometimes meaning "wider than bitstream register", and sometimes meaning "farther than memory cache distance".
|
|
* This function will try to mitigate main memory latency through the use of prefetching */
|
|
static size_t
|
|
ZSTD_decompressSequencesLong(ZSTD_DCtx* dctx,
|
|
void* dst, size_t maxDstSize,
|
|
const void* seqStart, size_t seqSize, int nbSeq,
|
|
const ZSTD_longOffset_e isLongOffset,
|
|
const int frame)
|
|
{
|
|
DEBUGLOG(5, "ZSTD_decompressSequencesLong");
|
|
#if DYNAMIC_BMI2
|
|
if (dctx->bmi2) {
|
|
return ZSTD_decompressSequencesLong_bmi2(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame);
|
|
}
|
|
#endif
|
|
return ZSTD_decompressSequencesLong_default(dctx, dst, maxDstSize, seqStart, seqSize, nbSeq, isLongOffset, frame);
|
|
}
|
|
#endif /* ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT */
|
|
|
|
|
|
|
|
#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
|
|
!defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
|
|
/* ZSTD_getLongOffsetsShare() :
|
|
* condition : offTable must be valid
|
|
* @return : "share" of long offsets (arbitrarily defined as > (1<<23))
|
|
* compared to maximum possible of (1<<OffFSELog) */
|
|
static unsigned
|
|
ZSTD_getLongOffsetsShare(const ZSTD_seqSymbol* offTable)
|
|
{
|
|
const void* ptr = offTable;
|
|
U32 const tableLog = ((const ZSTD_seqSymbol_header*)ptr)[0].tableLog;
|
|
const ZSTD_seqSymbol* table = offTable + 1;
|
|
U32 const max = 1 << tableLog;
|
|
U32 u, total = 0;
|
|
DEBUGLOG(5, "ZSTD_getLongOffsetsShare: (tableLog=%u)", tableLog);
|
|
|
|
assert(max <= (1 << OffFSELog)); /* max not too large */
|
|
for (u=0; u<max; u++) {
|
|
if (table[u].nbAdditionalBits > 22) total += 1;
|
|
}
|
|
|
|
assert(tableLog <= OffFSELog);
|
|
total <<= (OffFSELog - tableLog); /* scale to OffFSELog */
|
|
|
|
return total;
|
|
}
|
|
#endif
|
|
|
|
size_t
|
|
ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx,
|
|
void* dst, size_t dstCapacity,
|
|
const void* src, size_t srcSize, const int frame)
|
|
{ /* blockType == blockCompressed */
|
|
const BYTE* ip = (const BYTE*)src;
|
|
/* isLongOffset must be true if there are long offsets.
|
|
* Offsets are long if they are larger than 2^STREAM_ACCUMULATOR_MIN.
|
|
* We don't expect that to be the case in 64-bit mode.
|
|
* In block mode, window size is not known, so we have to be conservative.
|
|
* (note: but it could be evaluated from current-lowLimit)
|
|
*/
|
|
ZSTD_longOffset_e const isLongOffset = (ZSTD_longOffset_e)(MEM_32bits() && (!frame || (dctx->fParams.windowSize > (1ULL << STREAM_ACCUMULATOR_MIN))));
|
|
DEBUGLOG(5, "ZSTD_decompressBlock_internal (size : %u)", (U32)srcSize);
|
|
|
|
RETURN_ERROR_IF(srcSize >= ZSTD_BLOCKSIZE_MAX, srcSize_wrong, "");
|
|
|
|
/* Decode literals section */
|
|
{ size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
|
|
DEBUGLOG(5, "ZSTD_decodeLiteralsBlock : %u", (U32)litCSize);
|
|
if (ZSTD_isError(litCSize)) return litCSize;
|
|
ip += litCSize;
|
|
srcSize -= litCSize;
|
|
}
|
|
|
|
/* Build Decoding Tables */
|
|
{
|
|
/* These macros control at build-time which decompressor implementation
|
|
* we use. If neither is defined, we do some inspection and dispatch at
|
|
* runtime.
|
|
*/
|
|
#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
|
|
!defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
|
|
int usePrefetchDecoder = dctx->ddictIsCold;
|
|
#endif
|
|
int nbSeq;
|
|
size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, srcSize);
|
|
if (ZSTD_isError(seqHSize)) return seqHSize;
|
|
ip += seqHSize;
|
|
srcSize -= seqHSize;
|
|
|
|
RETURN_ERROR_IF(dst == NULL && nbSeq > 0, dstSize_tooSmall, "NULL not handled");
|
|
|
|
#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
|
|
!defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
|
|
if ( !usePrefetchDecoder
|
|
&& (!frame || (dctx->fParams.windowSize > (1<<24)))
|
|
&& (nbSeq>ADVANCED_SEQS) ) { /* could probably use a larger nbSeq limit */
|
|
U32 const shareLongOffsets = ZSTD_getLongOffsetsShare(dctx->OFTptr);
|
|
U32 const minShare = MEM_64bits() ? 7 : 20; /* heuristic values, correspond to 2.73% and 7.81% */
|
|
usePrefetchDecoder = (shareLongOffsets >= minShare);
|
|
}
|
|
#endif
|
|
|
|
dctx->ddictIsCold = 0;
|
|
|
|
#if !defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT) && \
|
|
!defined(ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG)
|
|
if (usePrefetchDecoder)
|
|
#endif
|
|
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_SHORT
|
|
return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame);
|
|
#endif
|
|
|
|
#ifndef ZSTD_FORCE_DECOMPRESS_SEQUENCES_LONG
|
|
/* else */
|
|
return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize, nbSeq, isLongOffset, frame);
|
|
#endif
|
|
}
|
|
}
|
|
|
|
|
|
void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst, size_t dstSize)
|
|
{
|
|
if (dst != dctx->previousDstEnd && dstSize > 0) { /* not contiguous */
|
|
dctx->dictEnd = dctx->previousDstEnd;
|
|
dctx->virtualStart = (const char*)dst - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->prefixStart));
|
|
dctx->prefixStart = dst;
|
|
dctx->previousDstEnd = dst;
|
|
}
|
|
}
|
|
|
|
|
|
size_t ZSTD_decompressBlock(ZSTD_DCtx* dctx,
|
|
void* dst, size_t dstCapacity,
|
|
const void* src, size_t srcSize)
|
|
{
|
|
size_t dSize;
|
|
ZSTD_checkContinuity(dctx, dst, dstCapacity);
|
|
dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 0);
|
|
dctx->previousDstEnd = (char*)dst + dSize;
|
|
return dSize;
|
|
}
|