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decompress.c
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/**
* Copyright (c) 2016-present, Yann Collet, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* LICENSE file in the root directory of https://github.com/facebook/zstd.
* An additional grant of patent rights can be found in the PATENTS file in the
* same directory.
*
* This program is free software; you can redistribute it and/or modify it under
* the terms of the GNU General Public License version 2 as published by the
* Free Software Foundation. This program is dual-licensed; you may select
* either version 2 of the GNU General Public License ("GPL") or BSD license
* ("BSD").
*/
/* ***************************************************************
* Tuning parameters
*****************************************************************/
/*!
* MAXWINDOWSIZE_DEFAULT :
* maximum window size accepted by DStream, by default.
* Frames requiring more memory will be rejected.
*/
#ifndef ZSTD_MAXWINDOWSIZE_DEFAULT
#define ZSTD_MAXWINDOWSIZE_DEFAULT ((1 << ZSTD_WINDOWLOG_MAX) + 1) /* defined within zstd.h */
#endif
/*-*******************************************************
* Dependencies
*********************************************************/
#include "fse.h"
#include "huf.h"
#include "mem.h" /* low level memory routines */
#include "zstd_internal.h"
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/string.h> /* memcpy, memmove, memset */
#define ZSTD_PREFETCH(ptr) __builtin_prefetch(ptr, 0, 0)
/*-*************************************
* Macros
***************************************/
#define ZSTD_isError ERR_isError /* for inlining */
#define FSE_isError ERR_isError
#define HUF_isError ERR_isError
/*_*******************************************************
* Memory operations
**********************************************************/
static void ZSTD_copy4(void *dst, const void *src) { memcpy(dst, src, 4); }
/*-*************************************************************
* Context management
***************************************************************/
typedef enum {
ZSTDds_getFrameHeaderSize,
ZSTDds_decodeFrameHeader,
ZSTDds_decodeBlockHeader,
ZSTDds_decompressBlock,
ZSTDds_decompressLastBlock,
ZSTDds_checkChecksum,
ZSTDds_decodeSkippableHeader,
ZSTDds_skipFrame
} ZSTD_dStage;
typedef struct {
FSE_DTable LLTable[FSE_DTABLE_SIZE_U32(LLFSELog)];
FSE_DTable OFTable[FSE_DTABLE_SIZE_U32(OffFSELog)];
FSE_DTable MLTable[FSE_DTABLE_SIZE_U32(MLFSELog)];
HUF_DTable hufTable[HUF_DTABLE_SIZE(HufLog)]; /* can accommodate HUF_decompress4X */
U64 workspace[HUF_DECOMPRESS_WORKSPACE_SIZE_U32 / 2];
U32 rep[ZSTD_REP_NUM];
} ZSTD_entropyTables_t;
struct ZSTD_DCtx_s {
const FSE_DTable *LLTptr;
const FSE_DTable *MLTptr;
const FSE_DTable *OFTptr;
const HUF_DTable *HUFptr;
ZSTD_entropyTables_t entropy;
const void *previousDstEnd; /* detect continuity */
const void *base; /* start of curr segment */
const void *vBase; /* virtual start of previous segment if it was just before curr one */
const void *dictEnd; /* end of previous segment */
size_t expected;
ZSTD_frameParams fParams;
blockType_e bType; /* used in ZSTD_decompressContinue(), to transfer blockType between header decoding and block decoding stages */
ZSTD_dStage stage;
U32 litEntropy;
U32 fseEntropy;
struct xxh64_state xxhState;
size_t headerSize;
U32 dictID;
const BYTE *litPtr;
ZSTD_customMem customMem;
size_t litSize;
size_t rleSize;
BYTE litBuffer[ZSTD_BLOCKSIZE_ABSOLUTEMAX + WILDCOPY_OVERLENGTH];
BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX];
}; /* typedef'd to ZSTD_DCtx within "zstd.h" */
size_t ZSTD_DCtxWorkspaceBound(void) { return ZSTD_ALIGN(sizeof(ZSTD_stack)) + ZSTD_ALIGN(sizeof(ZSTD_DCtx)); }
size_t ZSTD_decompressBegin(ZSTD_DCtx *dctx)
{
dctx->expected = ZSTD_frameHeaderSize_prefix;
dctx->stage = ZSTDds_getFrameHeaderSize;
dctx->previousDstEnd = NULL;
dctx->base = NULL;
dctx->vBase = NULL;
dctx->dictEnd = NULL;
dctx->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover both little and big endian */
dctx->litEntropy = dctx->fseEntropy = 0;
dctx->dictID = 0;
ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue));
memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue)); /* initial repcodes */
dctx->LLTptr = dctx->entropy.LLTable;
dctx->MLTptr = dctx->entropy.MLTable;
dctx->OFTptr = dctx->entropy.OFTable;
dctx->HUFptr = dctx->entropy.hufTable;
return 0;
}
ZSTD_DCtx *ZSTD_createDCtx_advanced(ZSTD_customMem customMem)
{
ZSTD_DCtx *dctx;
if (!customMem.customAlloc || !customMem.customFree)
return NULL;
dctx = (ZSTD_DCtx *)ZSTD_malloc(sizeof(ZSTD_DCtx), customMem);
if (!dctx)
return NULL;
memcpy(&dctx->customMem, &customMem, sizeof(customMem));
ZSTD_decompressBegin(dctx);
return dctx;
}
ZSTD_DCtx *ZSTD_initDCtx(void *workspace, size_t workspaceSize)
{
ZSTD_customMem const stackMem = ZSTD_initStack(workspace, workspaceSize);
return ZSTD_createDCtx_advanced(stackMem);
}
size_t ZSTD_freeDCtx(ZSTD_DCtx *dctx)
{
if (dctx == NULL)
return 0; /* support free on NULL */
ZSTD_free(dctx, dctx->customMem);
return 0; /* reserved as a potential error code in the future */
}
void ZSTD_copyDCtx(ZSTD_DCtx *dstDCtx, const ZSTD_DCtx *srcDCtx)
{
size_t const workSpaceSize = (ZSTD_BLOCKSIZE_ABSOLUTEMAX + WILDCOPY_OVERLENGTH) + ZSTD_frameHeaderSize_max;
memcpy(dstDCtx, srcDCtx, sizeof(ZSTD_DCtx) - workSpaceSize); /* no need to copy workspace */
}
static void ZSTD_refDDict(ZSTD_DCtx *dstDCtx, const ZSTD_DDict *ddict);
/*-*************************************************************
* Decompression section
***************************************************************/
/*! ZSTD_isFrame() :
* Tells if the content of `buffer` starts with a valid Frame Identifier.
* Note : Frame Identifier is 4 bytes. If `size < 4`, @return will always be 0.
* Note 2 : Legacy Frame Identifiers are considered valid only if Legacy Support is enabled.
* Note 3 : Skippable Frame Identifiers are considered valid. */
unsigned ZSTD_isFrame(const void *buffer, size_t size)
{
if (size < 4)
return 0;
{
U32 const magic = ZSTD_readLE32(buffer);
if (magic == ZSTD_MAGICNUMBER)
return 1;
if ((magic & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START)
return 1;
}
return 0;
}
/** ZSTD_frameHeaderSize() :
* srcSize must be >= ZSTD_frameHeaderSize_prefix.
* @return : size of the Frame Header */
static size_t ZSTD_frameHeaderSize(const void *src, size_t srcSize)
{
if (srcSize < ZSTD_frameHeaderSize_prefix)
return ERROR(srcSize_wrong);
{
BYTE const fhd = ((const BYTE *)src)[4];
U32 const dictID = fhd & 3;
U32 const singleSegment = (fhd >> 5) & 1;
U32 const fcsId = fhd >> 6;
return ZSTD_frameHeaderSize_prefix + !singleSegment + ZSTD_did_fieldSize[dictID] + ZSTD_fcs_fieldSize[fcsId] + (singleSegment && !fcsId);
}
}
/** ZSTD_getFrameParams() :
* decode Frame Header, or require larger `srcSize`.
* @return : 0, `fparamsPtr` is correctly filled,
* >0, `srcSize` is too small, result is expected `srcSize`,
* or an error code, which can be tested using ZSTD_isError() */
size_t ZSTD_getFrameParams(ZSTD_frameParams *fparamsPtr, const void *src, size_t srcSize)
{
const BYTE *ip = (const BYTE *)src;
if (srcSize < ZSTD_frameHeaderSize_prefix)
return ZSTD_frameHeaderSize_prefix;
if (ZSTD_readLE32(src) != ZSTD_MAGICNUMBER) {
if ((ZSTD_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
if (srcSize < ZSTD_skippableHeaderSize)
return ZSTD_skippableHeaderSize; /* magic number + skippable frame length */
memset(fparamsPtr, 0, sizeof(*fparamsPtr));
fparamsPtr->frameContentSize = ZSTD_readLE32((const char *)src + 4);
fparamsPtr->windowSize = 0; /* windowSize==0 means a frame is skippable */
return 0;
}
return ERROR(prefix_unknown);
}
/* ensure there is enough `srcSize` to fully read/decode frame header */
{
size_t const fhsize = ZSTD_frameHeaderSize(src, srcSize);
if (srcSize < fhsize)
return fhsize;
}
{
BYTE const fhdByte = ip[4];
size_t pos = 5;
U32 const dictIDSizeCode = fhdByte & 3;
U32 const checksumFlag = (fhdByte >> 2) & 1;
U32 const singleSegment = (fhdByte >> 5) & 1;
U32 const fcsID = fhdByte >> 6;
U32 const windowSizeMax = 1U << ZSTD_WINDOWLOG_MAX;
U32 windowSize = 0;
U32 dictID = 0;
U64 frameContentSize = 0;
if ((fhdByte & 0x08) != 0)
return ERROR(frameParameter_unsupported); /* reserved bits, which must be zero */
if (!singleSegment) {
BYTE const wlByte = ip[pos++];
U32 const windowLog = (wlByte >> 3) + ZSTD_WINDOWLOG_ABSOLUTEMIN;
if (windowLog > ZSTD_WINDOWLOG_MAX)
return ERROR(frameParameter_windowTooLarge); /* avoids issue with 1 << windowLog */
windowSize = (1U << windowLog);
windowSize += (windowSize >> 3) * (wlByte & 7);
}
switch (dictIDSizeCode) {
default: /* impossible */
case 0: break;
case 1:
dictID = ip[pos];
pos++;
break;
case 2:
dictID = ZSTD_readLE16(ip + pos);
pos += 2;
break;
case 3:
dictID = ZSTD_readLE32(ip + pos);
pos += 4;
break;
}
switch (fcsID) {
default: /* impossible */
case 0:
if (singleSegment)
frameContentSize = ip[pos];
break;
case 1: frameContentSize = ZSTD_readLE16(ip + pos) + 256; break;
case 2: frameContentSize = ZSTD_readLE32(ip + pos); break;
case 3: frameContentSize = ZSTD_readLE64(ip + pos); break;
}
if (!windowSize)
windowSize = (U32)frameContentSize;
if (windowSize > windowSizeMax)
return ERROR(frameParameter_windowTooLarge);
fparamsPtr->frameContentSize = frameContentSize;
fparamsPtr->windowSize = windowSize;
fparamsPtr->dictID = dictID;
fparamsPtr->checksumFlag = checksumFlag;
}
return 0;
}
/** ZSTD_getFrameContentSize() :
* compatible with legacy mode
* @return : decompressed size of the single frame pointed to be `src` if known, otherwise
* - ZSTD_CONTENTSIZE_UNKNOWN if the size cannot be determined
* - ZSTD_CONTENTSIZE_ERROR if an error occurred (e.g. invalid magic number, srcSize too small) */
unsigned long long ZSTD_getFrameContentSize(const void *src, size_t srcSize)
{
{
ZSTD_frameParams fParams;
if (ZSTD_getFrameParams(&fParams, src, srcSize) != 0)
return ZSTD_CONTENTSIZE_ERROR;
if (fParams.windowSize == 0) {
/* Either skippable or empty frame, size == 0 either way */
return 0;
} else if (fParams.frameContentSize != 0) {
return fParams.frameContentSize;
} else {
return ZSTD_CONTENTSIZE_UNKNOWN;
}
}
}
/** ZSTD_findDecompressedSize() :
* compatible with legacy mode
* `srcSize` must be the exact length of some number of ZSTD compressed and/or
* skippable frames
* @return : decompressed size of the frames contained */
unsigned long long ZSTD_findDecompressedSize(const void *src, size_t srcSize)
{
{
unsigned long long totalDstSize = 0;
while (srcSize >= ZSTD_frameHeaderSize_prefix) {
const U32 magicNumber = ZSTD_readLE32(src);
if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
size_t skippableSize;
if (srcSize < ZSTD_skippableHeaderSize)
return ERROR(srcSize_wrong);
skippableSize = ZSTD_readLE32((const BYTE *)src + 4) + ZSTD_skippableHeaderSize;
if (srcSize < skippableSize) {
return ZSTD_CONTENTSIZE_ERROR;
}
src = (const BYTE *)src + skippableSize;
srcSize -= skippableSize;
continue;
}
{
unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize);
if (ret >= ZSTD_CONTENTSIZE_ERROR)
return ret;
/* check for overflow */
if (totalDstSize + ret < totalDstSize)
return ZSTD_CONTENTSIZE_ERROR;
totalDstSize += ret;
}
{
size_t const frameSrcSize = ZSTD_findFrameCompressedSize(src, srcSize);
if (ZSTD_isError(frameSrcSize)) {
return ZSTD_CONTENTSIZE_ERROR;
}
src = (const BYTE *)src + frameSrcSize;
srcSize -= frameSrcSize;
}
}
if (srcSize) {
return ZSTD_CONTENTSIZE_ERROR;
}
return totalDstSize;
}
}
/** ZSTD_decodeFrameHeader() :
* `headerSize` must be the size provided by ZSTD_frameHeaderSize().
* @return : 0 if success, or an error code, which can be tested using ZSTD_isError() */
static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx *dctx, const void *src, size_t headerSize)
{
size_t const result = ZSTD_getFrameParams(&(dctx->fParams), src, headerSize);
if (ZSTD_isError(result))
return result; /* invalid header */
if (result > 0)
return ERROR(srcSize_wrong); /* headerSize too small */
if (dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID))
return ERROR(dictionary_wrong);
if (dctx->fParams.checksumFlag)
xxh64_reset(&dctx->xxhState, 0);
return 0;
}
typedef struct {
blockType_e blockType;
U32 lastBlock;
U32 origSize;
} blockProperties_t;
/*! ZSTD_getcBlockSize() :
* Provides the size of compressed block from block header `src` */
size_t ZSTD_getcBlockSize(const void *src, size_t srcSize, blockProperties_t *bpPtr)
{
if (srcSize < ZSTD_blockHeaderSize)
return ERROR(srcSize_wrong);
{
U32 const cBlockHeader = ZSTD_readLE24(src);
U32 const cSize = cBlockHeader >> 3;
bpPtr->lastBlock = cBlockHeader & 1;
bpPtr->blockType = (blockType_e)((cBlockHeader >> 1) & 3);
bpPtr->origSize = cSize; /* only useful for RLE */
if (bpPtr->blockType == bt_rle)
return 1;
if (bpPtr->blockType == bt_reserved)
return ERROR(corruption_detected);
return cSize;
}
}
static size_t ZSTD_copyRawBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize)
{
if (srcSize > dstCapacity)
return ERROR(dstSize_tooSmall);
memcpy(dst, src, srcSize);
return srcSize;
}
static size_t ZSTD_setRleBlock(void *dst, size_t dstCapacity, const void *src, size_t srcSize, size_t regenSize)
{
if (srcSize != 1)
return ERROR(srcSize_wrong);
if (regenSize > dstCapacity)
return ERROR(dstSize_tooSmall);
memset(dst, *(const BYTE *)src, regenSize);
return regenSize;
}
/*! ZSTD_decodeLiteralsBlock() :
@return : nb of bytes read from src (< srcSize ) */
size_t ZSTD_decodeLiteralsBlock(ZSTD_DCtx *dctx, const void *src, size_t srcSize) /* note : srcSize < BLOCKSIZE */
{
if (srcSize < MIN_CBLOCK_SIZE)
return ERROR(corruption_detected);
{
const BYTE *const istart = (const BYTE *)src;
symbolEncodingType_e const litEncType = (symbolEncodingType_e)(istart[0] & 3);
switch (litEncType) {
case set_repeat:
if (dctx->litEntropy == 0)
return ERROR(dictionary_corrupted);
/* fall-through */
case set_compressed:
if (srcSize < 5)
return ERROR(corruption_detected); /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need up to 5 for case 3 */
{
size_t lhSize, litSize, litCSize;
U32 singleStream = 0;
U32 const lhlCode = (istart[0] >> 2) & 3;
U32 const lhc = ZSTD_readLE32(istart);
switch (lhlCode) {
case 0:
case 1:
default: /* note : default is impossible, since lhlCode into [0..3] */
/* 2 - 2 - 10 - 10 */
singleStream = !lhlCode;
lhSize = 3;
litSize = (lhc >> 4) & 0x3FF;
litCSize = (lhc >> 14) & 0x3FF;
break;
case 2:
/* 2 - 2 - 14 - 14 */
lhSize = 4;
litSize = (lhc >> 4) & 0x3FFF;
litCSize = lhc >> 18;
break;
case 3:
/* 2 - 2 - 18 - 18 */
lhSize = 5;
litSize = (lhc >> 4) & 0x3FFFF;
litCSize = (lhc >> 22) + (istart[4] << 10);
break;
}
if (litSize > ZSTD_BLOCKSIZE_ABSOLUTEMAX)
return ERROR(corruption_detected);
if (litCSize + lhSize > srcSize)
return ERROR(corruption_detected);
if (HUF_isError(
(litEncType == set_repeat)
? (singleStream ? HUF_decompress1X_usingDTable(dctx->litBuffer, litSize, istart + lhSize, litCSize, dctx->HUFptr)
: HUF_decompress4X_usingDTable(dctx->litBuffer, litSize, istart + lhSize, litCSize, dctx->HUFptr))
: (singleStream
? HUF_decompress1X2_DCtx_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart + lhSize, litCSize,
dctx->entropy.workspace, sizeof(dctx->entropy.workspace))
: HUF_decompress4X_hufOnly_wksp(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart + lhSize, litCSize,
dctx->entropy.workspace, sizeof(dctx->entropy.workspace)))))
return ERROR(corruption_detected);
dctx->litPtr = dctx->litBuffer;
dctx->litSize = litSize;
dctx->litEntropy = 1;
if (litEncType == set_compressed)
dctx->HUFptr = dctx->entropy.hufTable;
memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
return litCSize + lhSize;
}
case set_basic: {
size_t litSize, lhSize;
U32 const lhlCode = ((istart[0]) >> 2) & 3;
switch (lhlCode) {
case 0:
case 2:
default: /* note : default is impossible, since lhlCode into [0..3] */
lhSize = 1;
litSize = istart[0] >> 3;
break;
case 1:
lhSize = 2;
litSize = ZSTD_readLE16(istart) >> 4;
break;
case 3:
lhSize = 3;
litSize = ZSTD_readLE24(istart) >> 4;
break;
}
if (lhSize + litSize + WILDCOPY_OVERLENGTH > srcSize) { /* risk reading beyond src buffer with wildcopy */
if (litSize + lhSize > srcSize)
return ERROR(corruption_detected);
memcpy(dctx->litBuffer, istart + lhSize, litSize);
dctx->litPtr = dctx->litBuffer;
dctx->litSize = litSize;
memset(dctx->litBuffer + dctx->litSize, 0, WILDCOPY_OVERLENGTH);
return lhSize + litSize;
}
/* direct reference into compressed stream */
dctx->litPtr = istart + lhSize;
dctx->litSize = litSize;
return lhSize + litSize;
}
case set_rle: {
U32 const lhlCode = ((istart[0]) >> 2) & 3;
size_t litSize, lhSize;
switch (lhlCode) {
case 0:
case 2:
default: /* note : default is impossible, since lhlCode into [0..3] */
lhSize = 1;
litSize = istart[0] >> 3;
break;
case 1:
lhSize = 2;
litSize = ZSTD_readLE16(istart) >> 4;
break;
case 3:
lhSize = 3;
litSize = ZSTD_readLE24(istart) >> 4;
if (srcSize < 4)
return ERROR(corruption_detected); /* srcSize >= MIN_CBLOCK_SIZE == 3; here we need lhSize+1 = 4 */
break;
}
if (litSize > ZSTD_BLOCKSIZE_ABSOLUTEMAX)
return ERROR(corruption_detected);
memset(dctx->litBuffer, istart[lhSize], litSize + WILDCOPY_OVERLENGTH);
dctx->litPtr = dctx->litBuffer;
dctx->litSize = litSize;
return lhSize + 1;
}
default:
return ERROR(corruption_detected); /* impossible */
}
}
}
typedef union {
FSE_decode_t realData;
U32 alignedBy4;
} FSE_decode_t4;
static const FSE_decode_t4 LL_defaultDTable[(1 << LL_DEFAULTNORMLOG) + 1] = {
{{LL_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
{{0, 0, 4}}, /* 0 : base, symbol, bits */
{{16, 0, 4}},
{{32, 1, 5}},
{{0, 3, 5}},
{{0, 4, 5}},
{{0, 6, 5}},
{{0, 7, 5}},
{{0, 9, 5}},
{{0, 10, 5}},
{{0, 12, 5}},
{{0, 14, 6}},
{{0, 16, 5}},
{{0, 18, 5}},
{{0, 19, 5}},
{{0, 21, 5}},
{{0, 22, 5}},
{{0, 24, 5}},
{{32, 25, 5}},
{{0, 26, 5}},
{{0, 27, 6}},
{{0, 29, 6}},
{{0, 31, 6}},
{{32, 0, 4}},
{{0, 1, 4}},
{{0, 2, 5}},
{{32, 4, 5}},
{{0, 5, 5}},
{{32, 7, 5}},
{{0, 8, 5}},
{{32, 10, 5}},
{{0, 11, 5}},
{{0, 13, 6}},
{{32, 16, 5}},
{{0, 17, 5}},
{{32, 19, 5}},
{{0, 20, 5}},
{{32, 22, 5}},
{{0, 23, 5}},
{{0, 25, 4}},
{{16, 25, 4}},
{{32, 26, 5}},
{{0, 28, 6}},
{{0, 30, 6}},
{{48, 0, 4}},
{{16, 1, 4}},
{{32, 2, 5}},
{{32, 3, 5}},
{{32, 5, 5}},
{{32, 6, 5}},
{{32, 8, 5}},
{{32, 9, 5}},
{{32, 11, 5}},
{{32, 12, 5}},
{{0, 15, 6}},
{{32, 17, 5}},
{{32, 18, 5}},
{{32, 20, 5}},
{{32, 21, 5}},
{{32, 23, 5}},
{{32, 24, 5}},
{{0, 35, 6}},
{{0, 34, 6}},
{{0, 33, 6}},
{{0, 32, 6}},
}; /* LL_defaultDTable */
static const FSE_decode_t4 ML_defaultDTable[(1 << ML_DEFAULTNORMLOG) + 1] = {
{{ML_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
{{0, 0, 6}}, /* 0 : base, symbol, bits */
{{0, 1, 4}},
{{32, 2, 5}},
{{0, 3, 5}},
{{0, 5, 5}},
{{0, 6, 5}},
{{0, 8, 5}},
{{0, 10, 6}},
{{0, 13, 6}},
{{0, 16, 6}},
{{0, 19, 6}},
{{0, 22, 6}},
{{0, 25, 6}},
{{0, 28, 6}},
{{0, 31, 6}},
{{0, 33, 6}},
{{0, 35, 6}},
{{0, 37, 6}},
{{0, 39, 6}},
{{0, 41, 6}},
{{0, 43, 6}},
{{0, 45, 6}},
{{16, 1, 4}},
{{0, 2, 4}},
{{32, 3, 5}},
{{0, 4, 5}},
{{32, 6, 5}},
{{0, 7, 5}},
{{0, 9, 6}},
{{0, 12, 6}},
{{0, 15, 6}},
{{0, 18, 6}},
{{0, 21, 6}},
{{0, 24, 6}},
{{0, 27, 6}},
{{0, 30, 6}},
{{0, 32, 6}},
{{0, 34, 6}},
{{0, 36, 6}},
{{0, 38, 6}},
{{0, 40, 6}},
{{0, 42, 6}},
{{0, 44, 6}},
{{32, 1, 4}},
{{48, 1, 4}},
{{16, 2, 4}},
{{32, 4, 5}},
{{32, 5, 5}},
{{32, 7, 5}},
{{32, 8, 5}},
{{0, 11, 6}},
{{0, 14, 6}},
{{0, 17, 6}},
{{0, 20, 6}},
{{0, 23, 6}},
{{0, 26, 6}},
{{0, 29, 6}},
{{0, 52, 6}},
{{0, 51, 6}},
{{0, 50, 6}},
{{0, 49, 6}},
{{0, 48, 6}},
{{0, 47, 6}},
{{0, 46, 6}},
}; /* ML_defaultDTable */
static const FSE_decode_t4 OF_defaultDTable[(1 << OF_DEFAULTNORMLOG) + 1] = {
{{OF_DEFAULTNORMLOG, 1, 1}}, /* header : tableLog, fastMode, fastMode */
{{0, 0, 5}}, /* 0 : base, symbol, bits */
{{0, 6, 4}},
{{0, 9, 5}},
{{0, 15, 5}},
{{0, 21, 5}},
{{0, 3, 5}},
{{0, 7, 4}},
{{0, 12, 5}},
{{0, 18, 5}},
{{0, 23, 5}},
{{0, 5, 5}},
{{0, 8, 4}},
{{0, 14, 5}},
{{0, 20, 5}},
{{0, 2, 5}},
{{16, 7, 4}},
{{0, 11, 5}},
{{0, 17, 5}},
{{0, 22, 5}},
{{0, 4, 5}},
{{16, 8, 4}},
{{0, 13, 5}},
{{0, 19, 5}},
{{0, 1, 5}},
{{16, 6, 4}},
{{0, 10, 5}},
{{0, 16, 5}},
{{0, 28, 5}},
{{0, 27, 5}},
{{0, 26, 5}},
{{0, 25, 5}},
{{0, 24, 5}},
}; /* OF_defaultDTable */
/*! ZSTD_buildSeqTable() :
@return : nb bytes read from src,
or an error code if it fails, testable with ZSTD_isError()
*/
static size_t ZSTD_buildSeqTable(FSE_DTable *DTableSpace, const FSE_DTable **DTablePtr, symbolEncodingType_e type, U32 max, U32 maxLog, const void *src,
size_t srcSize, const FSE_decode_t4 *defaultTable, U32 flagRepeatTable, void *workspace, size_t workspaceSize)
{
const void *const tmpPtr = defaultTable; /* bypass strict aliasing */
switch (type) {
case set_rle:
if (!srcSize)
return ERROR(srcSize_wrong);
if ((*(const BYTE *)src) > max)
return ERROR(corruption_detected);
FSE_buildDTable_rle(DTableSpace, *(const BYTE *)src);
*DTablePtr = DTableSpace;
return 1;
case set_basic: *DTablePtr = (const FSE_DTable *)tmpPtr; return 0;
case set_repeat:
if (!flagRepeatTable)
return ERROR(corruption_detected);
return 0;
default: /* impossible */
case set_compressed: {
U32 tableLog;
S16 *norm = (S16 *)workspace;
size_t const spaceUsed32 = ALIGN(sizeof(S16) * (MaxSeq + 1), sizeof(U32)) >> 2;
if ((spaceUsed32 << 2) > workspaceSize)
return ERROR(GENERIC);
workspace = (U32 *)workspace + spaceUsed32;
workspaceSize -= (spaceUsed32 << 2);
{
size_t const headerSize = FSE_readNCount(norm, &max, &tableLog, src, srcSize);
if (FSE_isError(headerSize))
return ERROR(corruption_detected);
if (tableLog > maxLog)
return ERROR(corruption_detected);
FSE_buildDTable_wksp(DTableSpace, norm, max, tableLog, workspace, workspaceSize);
*DTablePtr = DTableSpace;
return headerSize;
}
}
}
}
size_t ZSTD_decodeSeqHeaders(ZSTD_DCtx *dctx, int *nbSeqPtr, const void *src, size_t srcSize)
{
const BYTE *const istart = (const BYTE *const)src;
const BYTE *const iend = istart + srcSize;
const BYTE *ip = istart;
/* check */
if (srcSize < MIN_SEQUENCES_SIZE)
return ERROR(srcSize_wrong);
/* SeqHead */
{
int nbSeq = *ip++;
if (!nbSeq) {
*nbSeqPtr = 0;
return 1;
}
if (nbSeq > 0x7F) {
if (nbSeq == 0xFF) {
if (ip + 2 > iend)
return ERROR(srcSize_wrong);
nbSeq = ZSTD_readLE16(ip) + LONGNBSEQ, ip += 2;
} else {
if (ip >= iend)
return ERROR(srcSize_wrong);
nbSeq = ((nbSeq - 0x80) << 8) + *ip++;
}
}
*nbSeqPtr = nbSeq;
}
/* FSE table descriptors */
if (ip + 4 > iend)
return ERROR(srcSize_wrong); /* minimum possible size */
{
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_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
if (ZSTD_isError(llhSize))
return ERROR(corruption_detected);
ip += llhSize;
}
{
size_t const ofhSize = ZSTD_buildSeqTable(dctx->entropy.OFTable, &dctx->OFTptr, OFtype, MaxOff, OffFSELog, ip, iend - ip,
OF_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
if (ZSTD_isError(ofhSize))
return ERROR(corruption_detected);
ip += ofhSize;
}
{
size_t const mlhSize = ZSTD_buildSeqTable(dctx->entropy.MLTable, &dctx->MLTptr, MLtype, MaxML, MLFSELog, ip, iend - ip,
ML_defaultDTable, dctx->fseEntropy, dctx->entropy.workspace, sizeof(dctx->entropy.workspace));
if (ZSTD_isError(mlhSize))
return ERROR(corruption_detected);
ip += mlhSize;
}
}
return ip - istart;
}
typedef struct {
size_t litLength;
size_t matchLength;
size_t offset;
const BYTE *match;
} seq_t;
typedef struct {
BIT_DStream_t DStream;
FSE_DState_t stateLL;
FSE_DState_t stateOffb;
FSE_DState_t stateML;
size_t prevOffset[ZSTD_REP_NUM];
const BYTE *base;
size_t pos;
uPtrDiff gotoDict;
} seqState_t;
FORCE_NOINLINE
size_t ZSTD_execSequenceLast7(BYTE *op, BYTE *const oend, seq_t sequence, const BYTE **litPtr, const BYTE *const litLimit, const BYTE *const base,
const BYTE *const vBase, 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;
const BYTE *const iLitEnd = *litPtr + sequence.litLength;
const BYTE *match = oLitEnd - sequence.offset;
/* check */
if (oMatchEnd > oend)
return ERROR(dstSize_tooSmall); /* last match must start at a minimum distance of WILDCOPY_OVERLENGTH from oend */
if (iLitEnd > litLimit)
return ERROR(corruption_detected); /* over-read beyond lit buffer */
if (oLitEnd <= oend_w)
return ERROR(GENERIC); /* Precondition */
/* copy literals */
if (op < oend_w) {
ZSTD_wildcopy(op, *litPtr, oend_w - op);
*litPtr += oend_w - op;
op = oend_w;
}
while (op < oLitEnd)
*op++ = *(*litPtr)++;
/* copy Match */
if (sequence.offset > (size_t)(oLitEnd - base)) {
/* offset beyond prefix */
if (sequence.offset > (size_t)(oLitEnd - vBase))
return ERROR(corruption_detected);
match = dictEnd - (base - match);
if (match + sequence.matchLength <= dictEnd) {
memmove(oLitEnd, match, sequence.matchLength);
return sequenceLength;
}
/* span extDict & currPrefixSegment */
{
size_t const length1 = dictEnd - match;
memmove(oLitEnd, match, length1);
op = oLitEnd + length1;
sequence.matchLength -= length1;
match = base;
}
}
while (op < oMatchEnd)
*op++ = *match++;
return sequenceLength;
}
static seq_t ZSTD_decodeSequence(seqState_t *seqState)
{
seq_t seq;
U32 const llCode = FSE_peekSymbol(&seqState->stateLL);
U32 const mlCode = FSE_peekSymbol(&seqState->stateML);
U32 const ofCode = FSE_peekSymbol(&seqState->stateOffb); /* <= maxOff, by table construction */
U32 const llBits = LL_bits[llCode];
U32 const mlBits = ML_bits[mlCode];
U32 const ofBits = ofCode;
U32 const totalBits = llBits + mlBits + ofBits;
static const U32 LL_base[MaxLL + 1] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 18,
20, 22, 24, 28, 32, 40, 48, 64, 0x80, 0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000, 0x8000, 0x10000};
static const U32 ML_base[MaxML + 1] = {3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20,
21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 39, 41,
43, 47, 51, 59, 67, 83, 99, 0x83, 0x103, 0x203, 0x403, 0x803, 0x1003, 0x2003, 0x4003, 0x8003, 0x10003};
static const U32 OF_base[MaxOff + 1] = {0, 1, 1, 5, 0xD, 0x1D, 0x3D, 0x7D, 0xFD, 0x1FD,
0x3FD, 0x7FD, 0xFFD, 0x1FFD, 0x3FFD, 0x7FFD, 0xFFFD, 0x1FFFD, 0x3FFFD, 0x7FFFD,
0xFFFFD, 0x1FFFFD, 0x3FFFFD, 0x7FFFFD, 0xFFFFFD, 0x1FFFFFD, 0x3FFFFFD, 0x7FFFFFD, 0xFFFFFFD};
/* sequence */
{
size_t offset;
if (!ofCode)
offset = 0;
else {
offset = OF_base[ofCode] + BIT_readBitsFast(&seqState->DStream, ofBits); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */
if (ZSTD_32bits())
BIT_reloadDStream(&seqState->DStream);
}
if (ofCode <= 1) {
offset += (llCode == 0);
if (offset) {
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;
} else {
offset = seqState->prevOffset[0];
}
} else {
seqState->prevOffset[2] = seqState->prevOffset[1];
seqState->prevOffset[1] = seqState->prevOffset[0];
seqState->prevOffset[0] = offset;
}
seq.offset = offset;
}
seq.matchLength = ML_base[mlCode] + ((mlCode > 31) ? BIT_readBitsFast(&seqState->DStream, mlBits) : 0); /* <= 16 bits */
if (ZSTD_32bits() && (mlBits + llBits > 24))
BIT_reloadDStream(&seqState->DStream);
seq.litLength = LL_base[llCode] + ((llCode > 15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <= 16 bits */
if (ZSTD_32bits() || (totalBits > 64 - 7 - (LLFSELog + MLFSELog + OffFSELog)))
BIT_reloadDStream(&seqState->DStream);
/* ANS state update */
FSE_updateState(&seqState->stateLL, &seqState->DStream); /* <= 9 bits */
FSE_updateState(&seqState->stateML, &seqState->DStream); /* <= 9 bits */
if (ZSTD_32bits())
BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */