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zstd/lib/decompress/zstd_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 this source tree. An additional grant
* of patent rights can be found in the PATENTS file in the same directory.
*/
/* ***************************************************************
* Tuning parameters
*****************************************************************/
/*!
* HEAPMODE :
* Select how default decompression function ZSTD_decompress() will allocate memory,
* in memory stack (0), or in memory heap (1, requires malloc())
*/
#ifndef ZSTD_HEAPMODE
# define ZSTD_HEAPMODE 1
#endif
/*!
* LEGACY_SUPPORT :
* if set to 1, ZSTD_decompress() can decode older formats (v0.1+)
*/
#ifndef ZSTD_LEGACY_SUPPORT
# define ZSTD_LEGACY_SUPPORT 0
#endif
/*!
* 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 <string.h> /* memcpy, memmove, memset */
#include "mem.h" /* low level memory routines */
#define FSE_STATIC_LINKING_ONLY
#include "fse.h"
#define HUF_STATIC_LINKING_ONLY
#include "huf.h"
#include "zstd_internal.h"
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
# include "zstd_legacy.h"
#endif
#if defined(_MSC_VER)
# include <mmintrin.h> /* https://msdn.microsoft.com/fr-fr/library/84szxsww(v=vs.90).aspx */
# define ZSTD_PREFETCH(ptr) _mm_prefetch((const char*)ptr, _MM_HINT_T0)
#elif defined(__GNUC__)
# define ZSTD_PREFETCH(ptr) __builtin_prefetch(ptr, 0, 0)
#else
# define ZSTD_PREFETCH(ptr) /* disabled */
#endif
/*-*************************************
* 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 */
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 current segment */
const void* vBase; /* virtual start of previous segment if it was just before current one */
const void* dictEnd; /* end of previous segment */
size_t expected;
ZSTD_frameHeader 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;
XXH64_state_t 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_sizeof_DCtx (const ZSTD_DCtx* dctx) { return (dctx==NULL) ? 0 : sizeof(ZSTD_DCtx); }
size_t ZSTD_estimateDCtxSize(void) { return 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;
MEM_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) customMem = defaultCustomMem;
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_createDCtx(void)
{
return ZSTD_createDCtx_advanced(defaultCustomMem);
}
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 = MEM_readLE32(buffer);
if (magic == ZSTD_MAGICNUMBER) return 1;
if ((magic & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) return 1;
}
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
if (ZSTD_isLegacy(buffer, size)) return 1;
#endif
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_getFrameHeader() :
* decode Frame Header, or require larger `srcSize`.
* @return : 0, `zfhPtr` 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_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize)
{
const BYTE* ip = (const BYTE*)src;
if (srcSize < ZSTD_frameHeaderSize_prefix) return ZSTD_frameHeaderSize_prefix;
if (MEM_readLE32(src) != ZSTD_MAGICNUMBER) {
if ((MEM_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
/* skippable frame */
if (srcSize < ZSTD_skippableHeaderSize) return ZSTD_skippableHeaderSize; /* magic number + skippable frame length */
memset(zfhPtr, 0, sizeof(*zfhPtr));
zfhPtr->frameContentSize = MEM_readLE32((const char *)src + 4);
zfhPtr->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 = MEM_readLE16(ip+pos); pos+=2; break;
case 3 : dictID = MEM_readLE32(ip+pos); pos+=4; break;
}
switch(fcsID)
{
default: /* impossible */
case 0 : if (singleSegment) frameContentSize = ip[pos]; break;
case 1 : frameContentSize = MEM_readLE16(ip+pos)+256; break;
case 2 : frameContentSize = MEM_readLE32(ip+pos); break;
case 3 : frameContentSize = MEM_readLE64(ip+pos); break;
}
if (!windowSize) windowSize = (U32)frameContentSize;
if (windowSize > windowSizeMax) return ERROR(frameParameter_windowTooLarge);
zfhPtr->frameContentSize = frameContentSize;
zfhPtr->windowSize = windowSize;
zfhPtr->dictID = dictID;
zfhPtr->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)
{
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
if (ZSTD_isLegacy(src, srcSize)) {
unsigned long long const ret = ZSTD_getDecompressedSize_legacy(src, srcSize);
return ret == 0 ? ZSTD_CONTENTSIZE_UNKNOWN : ret;
}
#endif
{ ZSTD_frameHeader fParams;
if (ZSTD_getFrameHeader(&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 = MEM_readLE32(src);
if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
size_t skippableSize;
if (srcSize < ZSTD_skippableHeaderSize)
return ERROR(srcSize_wrong);
skippableSize = MEM_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_getDecompressedSize() :
* compatible with legacy mode
* @return : decompressed size if known, 0 otherwise
note : 0 can mean any of the following :
- decompressed size is not present within frame header
- frame header unknown / not supported
- frame header not complete (`srcSize` too small) */
unsigned long long ZSTD_getDecompressedSize(const void* src, size_t srcSize)
{
unsigned long long const ret = ZSTD_getFrameContentSize(src, srcSize);
return ret >= ZSTD_CONTENTSIZE_ERROR ? 0 : ret;
}
/** 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_getFrameHeader(&(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 = MEM_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 = MEM_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(dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize) :
HUF_decompress4X_hufOnly (dctx->entropy.hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize)) ))
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 = MEM_readLE16(istart) >> 4;
break;
case 3:
lhSize = 3;
litSize = MEM_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 = MEM_readLE16(istart) >> 4;
break;
case 3:
lhSize = 3;
litSize = MEM_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;
/* Default FSE distribution table for Literal Lengths */
static const FSE_decode_t4 LL_defaultDTable[(1<<LL_DEFAULTNORMLOG)+1] = {
{ { LL_DEFAULTNORMLOG, 1, 1 } }, /* header : tableLog, fastMode, fastMode */
/* base, symbol, bits */
{ { 0, 0, 4 } }, { { 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 */
/* Default FSE distribution table for Match Lengths */
static const FSE_decode_t4 ML_defaultDTable[(1<<ML_DEFAULTNORMLOG)+1] = {
{ { ML_DEFAULTNORMLOG, 1, 1 } }, /* header : tableLog, fastMode, fastMode */
/* base, symbol, bits */
{ { 0, 0, 6 } }, { { 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 */
/* Default FSE distribution table for Offset Codes */
static const FSE_decode_t4 OF_defaultDTable[(1<<OF_DEFAULTNORMLOG)+1] = {
{ { OF_DEFAULTNORMLOG, 1, 1 } }, /* header : tableLog, fastMode, fastMode */
/* base, symbol, bits */
{ { 0, 0, 5 } }, { { 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)
{
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[MaxSeq+1];
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(DTableSpace, norm, max, tableLog);
*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 = MEM_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);
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);
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);
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 & currentPrefixSegment */
{ 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 (MEM_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 (MEM_32bits() && (mlBits+llBits>24)) BIT_reloadDStream(&seqState->DStream);
seq.litLength = LL_base[llCode] + ((llCode>15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <= 16 bits */
if (MEM_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 (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */
return seq;
}
FORCE_INLINE
size_t ZSTD_execSequence(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 ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
/* copy Literals */
ZSTD_copy8(op, *litPtr);
if (sequence.litLength > 8)
ZSTD_wildcopy(op+8, (*litPtr)+8, sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
op = oLitEnd;
*litPtr = iLitEnd; /* update for next sequence */
/* copy Match */
if (sequence.offset > (size_t)(oLitEnd - base)) {
/* offset beyond prefix -> go into extDict */
if (sequence.offset > (size_t)(oLitEnd - vBase)) return ERROR(corruption_detected);
match = dictEnd + (match - base);
if (match + sequence.matchLength <= dictEnd) {
memmove(oLitEnd, match, sequence.matchLength);
return sequenceLength;
}
/* span extDict & currentPrefixSegment */
{ size_t const length1 = dictEnd - match;
memmove(oLitEnd, match, length1);
op = oLitEnd + length1;
sequence.matchLength -= length1;
match = base;
if (op > oend_w || sequence.matchLength < MINMATCH) {
U32 i;
for (i = 0; i < sequence.matchLength; ++i) op[i] = match[i];
return sequenceLength;
}
} }
/* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
/* match within prefix */
if (sequence.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[sequence.offset];
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
match += dec32table[sequence.offset];
ZSTD_copy4(op+4, match);
match -= sub2;
} else {
ZSTD_copy8(op, match);
}
op += 8; match += 8;
if (oMatchEnd > oend-(16-MINMATCH)) {
if (op < oend_w) {
ZSTD_wildcopy(op, match, oend_w - op);
match += oend_w - op;
op = oend_w;
}
while (op < oMatchEnd) *op++ = *match++;
} else {
ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8); /* works even if matchLength < 8 */
}
return sequenceLength;
}
static size_t ZSTD_decompressSequences(
ZSTD_DCtx* dctx,
void* dst, size_t maxDstSize,
const void* seqStart, size_t seqSize)
{
const BYTE* ip = (const BYTE*)seqStart;
const BYTE* const iend = ip + seqSize;
BYTE* const ostart = (BYTE* const)dst;
BYTE* const oend = ostart + maxDstSize;
BYTE* op = ostart;
const BYTE* litPtr = dctx->litPtr;
const BYTE* const litEnd = litPtr + dctx->litSize;
const BYTE* const base = (const BYTE*) (dctx->base);
const BYTE* const vBase = (const BYTE*) (dctx->vBase);
const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
int nbSeq;
/* Build Decoding Tables */
{ size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
if (ZSTD_isError(seqHSize)) return seqHSize;
ip += seqHSize;
}
/* Regen sequences */
if (nbSeq) {
seqState_t seqState;
dctx->fseEntropy = 1;
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; }
CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend-ip), corruption_detected);
FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
FSE_initDState(&seqState.stateML, &seqState.DStream, dctx->MLTptr);
for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && nbSeq ; ) {
nbSeq--;
{ seq_t const sequence = ZSTD_decodeSequence(&seqState);
size_t const oneSeqSize = ZSTD_execSequence(op, oend, sequence, &litPtr, litEnd, base, vBase, dictEnd);
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
op += oneSeqSize;
} }
/* check if reached exact end */
if (nbSeq) return ERROR(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;
if (lastLLSize > (size_t)(oend-op)) return ERROR(dstSize_tooSmall);
memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
}
return op-ostart;
}
FORCE_INLINE seq_t ZSTD_decodeSequenceLong_generic(seqState_t* seqState, int const longOffsets)
{
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 {
if (longOffsets) {
int const extraBits = ofBits - MIN(ofBits, STREAM_ACCUMULATOR_MIN);
offset = OF_base[ofCode] + (BIT_readBitsFast(&seqState->DStream, ofBits - extraBits) << extraBits);
if (MEM_32bits() || extraBits) BIT_reloadDStream(&seqState->DStream);
if (extraBits) offset += BIT_readBitsFast(&seqState->DStream, extraBits);
} else {
offset = OF_base[ofCode] + BIT_readBitsFast(&seqState->DStream, ofBits); /* <= (ZSTD_WINDOWLOG_MAX-1) bits */
if (MEM_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 (MEM_32bits() && (mlBits+llBits>24)) BIT_reloadDStream(&seqState->DStream);
seq.litLength = LL_base[llCode] + ((llCode>15) ? BIT_readBitsFast(&seqState->DStream, llBits) : 0); /* <= 16 bits */
if (MEM_32bits() ||
(totalBits > 64 - 7 - (LLFSELog+MLFSELog+OffFSELog)) ) BIT_reloadDStream(&seqState->DStream);
{ size_t const pos = seqState->pos + seq.litLength;
seq.match = seqState->base + pos - seq.offset; /* single memory segment */
if (seq.offset > pos) seq.match += seqState->gotoDict; /* separate memory segment */
seqState->pos = pos + seq.matchLength;
}
/* ANS state update */
FSE_updateState(&seqState->stateLL, &seqState->DStream); /* <= 9 bits */
FSE_updateState(&seqState->stateML, &seqState->DStream); /* <= 9 bits */
if (MEM_32bits()) BIT_reloadDStream(&seqState->DStream); /* <= 18 bits */
FSE_updateState(&seqState->stateOffb, &seqState->DStream); /* <= 8 bits */
return seq;
}
static seq_t ZSTD_decodeSequenceLong(seqState_t* seqState, unsigned const windowSize) {
if (ZSTD_highbit32(windowSize) > STREAM_ACCUMULATOR_MIN) {
return ZSTD_decodeSequenceLong_generic(seqState, 1);
} else {
return ZSTD_decodeSequenceLong_generic(seqState, 0);
}
}
FORCE_INLINE
size_t ZSTD_execSequenceLong(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 = sequence.match;
/* check */
#if 1
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 ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit, base, vBase, dictEnd);
#endif
/* copy Literals */
ZSTD_copy8(op, *litPtr);
if (sequence.litLength > 8)
ZSTD_wildcopy(op+8, (*litPtr)+8, sequence.litLength - 8); /* note : since oLitEnd <= oend-WILDCOPY_OVERLENGTH, no risk of overwrite beyond oend */
op = oLitEnd;
*litPtr = iLitEnd; /* update for next sequence */
/* copy Match */
#if 1
if (sequence.offset > (size_t)(oLitEnd - base)) {
/* offset beyond prefix */
if (sequence.offset > (size_t)(oLitEnd - vBase)) return ERROR(corruption_detected);
if (match + sequence.matchLength <= dictEnd) {
memmove(oLitEnd, match, sequence.matchLength);
return sequenceLength;
}
/* span extDict & currentPrefixSegment */
{ size_t const length1 = dictEnd - match;
memmove(oLitEnd, match, length1);
op = oLitEnd + length1;
sequence.matchLength -= length1;
match = base;
if (op > oend_w || sequence.matchLength < MINMATCH) {
U32 i;
for (i = 0; i < sequence.matchLength; ++i) op[i] = match[i];
return sequenceLength;
}
} }
/* Requirement: op <= oend_w && sequence.matchLength >= MINMATCH */
#endif
/* match within prefix */
if (sequence.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[sequence.offset];
op[0] = match[0];
op[1] = match[1];
op[2] = match[2];
op[3] = match[3];
match += dec32table[sequence.offset];
ZSTD_copy4(op+4, match);
match -= sub2;
} else {
ZSTD_copy8(op, match);
}
op += 8; match += 8;
if (oMatchEnd > oend-(16-MINMATCH)) {
if (op < oend_w) {
ZSTD_wildcopy(op, match, oend_w - op);
match += oend_w - op;
op = oend_w;
}
while (op < oMatchEnd) *op++ = *match++;
} else {
ZSTD_wildcopy(op, match, (ptrdiff_t)sequence.matchLength-8); /* works even if matchLength < 8 */
}
return sequenceLength;
}
static size_t ZSTD_decompressSequencesLong(
ZSTD_DCtx* dctx,
void* dst, size_t maxDstSize,
const void* seqStart, size_t seqSize)
{
const BYTE* ip = (const BYTE*)seqStart;
const BYTE* const iend = ip + seqSize;
BYTE* const ostart = (BYTE* const)dst;
BYTE* const oend = ostart + maxDstSize;
BYTE* op = ostart;
const BYTE* litPtr = dctx->litPtr;
const BYTE* const litEnd = litPtr + dctx->litSize;
const BYTE* const base = (const BYTE*) (dctx->base);
const BYTE* const vBase = (const BYTE*) (dctx->vBase);
const BYTE* const dictEnd = (const BYTE*) (dctx->dictEnd);
unsigned const windowSize = dctx->fParams.windowSize;
int nbSeq;
/* Build Decoding Tables */
{ size_t const seqHSize = ZSTD_decodeSeqHeaders(dctx, &nbSeq, ip, seqSize);
if (ZSTD_isError(seqHSize)) return seqHSize;
ip += seqHSize;
}
/* Regen sequences */
if (nbSeq) {
#define STORED_SEQS 4
#define STOSEQ_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;
{ U32 i; for (i=0; i<ZSTD_REP_NUM; i++) seqState.prevOffset[i] = dctx->entropy.rep[i]; }
seqState.base = base;
seqState.pos = (size_t)(op-base);
seqState.gotoDict = (uPtrDiff)dictEnd - (uPtrDiff)base; /* cast to avoid undefined behaviour */
CHECK_E(BIT_initDStream(&seqState.DStream, ip, iend-ip), corruption_detected);
FSE_initDState(&seqState.stateLL, &seqState.DStream, dctx->LLTptr);
FSE_initDState(&seqState.stateOffb, &seqState.DStream, dctx->OFTptr);
FSE_initDState(&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_decodeSequenceLong(&seqState, windowSize);
}
if (seqNb<seqAdvance) return ERROR(corruption_detected);
/* decode and decompress */
for ( ; (BIT_reloadDStream(&(seqState.DStream)) <= BIT_DStream_completed) && seqNb<nbSeq ; seqNb++) {
seq_t const sequence = ZSTD_decodeSequenceLong(&seqState, windowSize);
size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[(seqNb-ADVANCED_SEQS) & STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
if (ZSTD_isError(oneSeqSize)) return oneSeqSize;
ZSTD_PREFETCH(sequence.match);
sequences[seqNb&STOSEQ_MASK] = sequence;
op += oneSeqSize;
}
if (seqNb<nbSeq) return ERROR(corruption_detected);
/* finish queue */
seqNb -= seqAdvance;
for ( ; seqNb<nbSeq ; seqNb++) {
size_t const oneSeqSize = ZSTD_execSequenceLong(op, oend, sequences[seqNb&STOSEQ_MASK], &litPtr, litEnd, base, vBase, dictEnd);
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;
if (lastLLSize > (size_t)(oend-op)) return ERROR(dstSize_tooSmall);
memcpy(op, litPtr, lastLLSize);
op += lastLLSize;
}
return op-ostart;
}
static size_t ZSTD_decompressBlock_internal(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize)
{ /* blockType == blockCompressed */
const BYTE* ip = (const BYTE*)src;
if (srcSize >= ZSTD_BLOCKSIZE_ABSOLUTEMAX) return ERROR(srcSize_wrong);
/* Decode literals section */
{ size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
if (ZSTD_isError(litCSize)) return litCSize;
ip += litCSize;
srcSize -= litCSize;
}
if (sizeof(size_t) > 4) /* do not enable prefetching on 32-bits x86, as it's performance detrimental */
/* likely because of register pressure */
/* if that's the correct cause, then 32-bits ARM should be affected differently */
/* it would be good to test this on ARM real hardware, to see if prefetch version improves speed */
if (dctx->fParams.windowSize > (1<<23))
return ZSTD_decompressSequencesLong(dctx, dst, dstCapacity, ip, srcSize);
return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize);
}
static void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst)
{
if (dst != dctx->previousDstEnd) { /* not contiguous */
dctx->dictEnd = dctx->previousDstEnd;
dctx->vBase = (const char*)dst - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->base));
dctx->base = 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);
dSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize);
dctx->previousDstEnd = (char*)dst + dSize;
return dSize;
}
/** ZSTD_insertBlock() :
insert `src` block into `dctx` history. Useful to track uncompressed blocks. */
ZSTDLIB_API size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize)
{
ZSTD_checkContinuity(dctx, blockStart);
dctx->previousDstEnd = (const char*)blockStart + blockSize;
return blockSize;
}
size_t ZSTD_generateNxBytes(void* dst, size_t dstCapacity, BYTE byte, size_t length)
{
if (length > dstCapacity) return ERROR(dstSize_tooSmall);
memset(dst, byte, length);
return length;
}
/** ZSTD_findFrameCompressedSize() :
* compatible with legacy mode
* `src` must point to the start of a ZSTD frame, ZSTD legacy frame, or skippable frame
* `srcSize` must be at least as large as the frame contained
* @return : the compressed size of the frame starting at `src` */
size_t ZSTD_findFrameCompressedSize(const void *src, size_t srcSize)
{
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
if (ZSTD_isLegacy(src, srcSize)) return ZSTD_findFrameCompressedSizeLegacy(src, srcSize);
#endif
if (srcSize >= ZSTD_skippableHeaderSize &&
(MEM_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
return ZSTD_skippableHeaderSize + MEM_readLE32((const BYTE*)src + 4);
} else {
const BYTE* ip = (const BYTE*)src;
const BYTE* const ipstart = ip;
size_t remainingSize = srcSize;
ZSTD_frameHeader fParams;
size_t const headerSize = ZSTD_frameHeaderSize(ip, remainingSize);
if (ZSTD_isError(headerSize)) return headerSize;
/* Frame Header */
{ size_t const ret = ZSTD_getFrameHeader(&fParams, ip, remainingSize);
if (ZSTD_isError(ret)) return ret;
if (ret > 0) return ERROR(srcSize_wrong);
}
ip += headerSize;
remainingSize -= headerSize;
/* Loop on each block */
while (1) {
blockProperties_t blockProperties;
size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
if (ZSTD_isError(cBlockSize)) return cBlockSize;
if (ZSTD_blockHeaderSize + cBlockSize > remainingSize) return ERROR(srcSize_wrong);
ip += ZSTD_blockHeaderSize + cBlockSize;
remainingSize -= ZSTD_blockHeaderSize + cBlockSize;
if (blockProperties.lastBlock) break;
}
if (fParams.checksumFlag) { /* Frame content checksum */
if (remainingSize < 4) return ERROR(srcSize_wrong);
ip += 4;
remainingSize -= 4;
}
return ip - ipstart;
}
}
/*! ZSTD_decompressFrame() :
* @dctx must be properly initialized */
static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void** srcPtr, size_t *srcSizePtr)
{
const BYTE* ip = (const BYTE*)(*srcPtr);
BYTE* const ostart = (BYTE* const)dst;
BYTE* const oend = ostart + dstCapacity;
BYTE* op = ostart;
size_t remainingSize = *srcSizePtr;
/* check */
if (remainingSize < ZSTD_frameHeaderSize_min+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
/* Frame Header */
{ size_t const frameHeaderSize = ZSTD_frameHeaderSize(ip, ZSTD_frameHeaderSize_prefix);
if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
if (remainingSize < frameHeaderSize+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
CHECK_F(ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize));
ip += frameHeaderSize; remainingSize -= frameHeaderSize;
}
/* Loop on each block */
while (1) {
size_t decodedSize;
blockProperties_t blockProperties;
size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties);
if (ZSTD_isError(cBlockSize)) return cBlockSize;
ip += ZSTD_blockHeaderSize;
remainingSize -= ZSTD_blockHeaderSize;
if (cBlockSize > remainingSize) return ERROR(srcSize_wrong);
switch(blockProperties.blockType)
{
case bt_compressed:
decodedSize = ZSTD_decompressBlock_internal(dctx, op, oend-op, ip, cBlockSize);
break;
case bt_raw :
decodedSize = ZSTD_copyRawBlock(op, oend-op, ip, cBlockSize);
break;
case bt_rle :
decodedSize = ZSTD_generateNxBytes(op, oend-op, *ip, blockProperties.origSize);
break;
case bt_reserved :
default:
return ERROR(corruption_detected);
}
if (ZSTD_isError(decodedSize)) return decodedSize;
if (dctx->fParams.checksumFlag) XXH64_update(&dctx->xxhState, op, decodedSize);
op += decodedSize;
ip += cBlockSize;
remainingSize -= cBlockSize;
if (blockProperties.lastBlock) break;
}
if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */
U32 const checkCalc = (U32)XXH64_digest(&dctx->xxhState);
U32 checkRead;
if (remainingSize<4) return ERROR(checksum_wrong);
checkRead = MEM_readLE32(ip);
if (checkRead != checkCalc) return ERROR(checksum_wrong);
ip += 4;
remainingSize -= 4;
}
/* Allow caller to get size read */
*srcPtr = ip;
*srcSizePtr = remainingSize;
return op-ostart;
}
static const void* ZSTD_DDictDictContent(const ZSTD_DDict* ddict);
static size_t ZSTD_DDictDictSize(const ZSTD_DDict* ddict);
static size_t ZSTD_decompressMultiFrame(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void *dict, size_t dictSize,
const ZSTD_DDict* ddict)
{
void* const dststart = dst;
if (ddict) {
if (dict) {
/* programmer error, these two cases should be mutually exclusive */
return ERROR(GENERIC);
}
dict = ZSTD_DDictDictContent(ddict);
dictSize = ZSTD_DDictDictSize(ddict);
}
while (srcSize >= ZSTD_frameHeaderSize_prefix) {
U32 magicNumber;
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
if (ZSTD_isLegacy(src, srcSize)) {
size_t decodedSize;
size_t const frameSize = ZSTD_findFrameCompressedSizeLegacy(src, srcSize);
if (ZSTD_isError(frameSize)) return frameSize;
decodedSize = ZSTD_decompressLegacy(dst, dstCapacity, src, frameSize, dict, dictSize);
dst = (BYTE*)dst + decodedSize;
dstCapacity -= decodedSize;
src = (const BYTE*)src + frameSize;
srcSize -= frameSize;
continue;
}
#endif
magicNumber = MEM_readLE32(src);
if (magicNumber != ZSTD_MAGICNUMBER) {
if ((magicNumber & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) {
size_t skippableSize;
if (srcSize < ZSTD_skippableHeaderSize)
return ERROR(srcSize_wrong);
skippableSize = MEM_readLE32((const BYTE *)src + 4) +
ZSTD_skippableHeaderSize;
if (srcSize < skippableSize) {
return ERROR(srcSize_wrong);
}
src = (const BYTE *)src + skippableSize;
srcSize -= skippableSize;
continue;
} else {
return ERROR(prefix_unknown);
}
}
if (ddict) {
/* we were called from ZSTD_decompress_usingDDict */
ZSTD_refDDict(dctx, ddict);
} else {
/* this will initialize correctly with no dict if dict == NULL, so
* use this in all cases but ddict */
CHECK_F(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize));
}
ZSTD_checkContinuity(dctx, dst);
{ const size_t res = ZSTD_decompressFrame(dctx, dst, dstCapacity,
&src, &srcSize);
if (ZSTD_isError(res)) return res;
/* don't need to bounds check this, ZSTD_decompressFrame will have
* already */
dst = (BYTE*)dst + res;
dstCapacity -= res;
}
}
if (srcSize) return ERROR(srcSize_wrong); /* input not entirely consumed */
return (BYTE*)dst - (BYTE*)dststart;
}
size_t ZSTD_decompress_usingDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const void* dict, size_t dictSize)
{
return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize, dict, dictSize, NULL);
}
size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
return ZSTD_decompress_usingDict(dctx, dst, dstCapacity, src, srcSize, NULL, 0);
}
size_t ZSTD_decompress(void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
#if defined(ZSTD_HEAPMODE) && (ZSTD_HEAPMODE==1)
size_t regenSize;
ZSTD_DCtx* const dctx = ZSTD_createDCtx();
if (dctx==NULL) return ERROR(memory_allocation);
regenSize = ZSTD_decompressDCtx(dctx, dst, dstCapacity, src, srcSize);
ZSTD_freeDCtx(dctx);
return regenSize;
#else /* stack mode */
ZSTD_DCtx dctx;
return ZSTD_decompressDCtx(&dctx, dst, dstCapacity, src, srcSize);
#endif
}
/*-**************************************
* Advanced Streaming Decompression API
* Bufferless and synchronous
****************************************/
size_t ZSTD_nextSrcSizeToDecompress(ZSTD_DCtx* dctx) { return dctx->expected; }
ZSTD_nextInputType_e ZSTD_nextInputType(ZSTD_DCtx* dctx) {
switch(dctx->stage)
{
default: /* should not happen */
case ZSTDds_getFrameHeaderSize:
case ZSTDds_decodeFrameHeader:
return ZSTDnit_frameHeader;
case ZSTDds_decodeBlockHeader:
return ZSTDnit_blockHeader;
case ZSTDds_decompressBlock:
return ZSTDnit_block;
case ZSTDds_decompressLastBlock:
return ZSTDnit_lastBlock;
case ZSTDds_checkChecksum:
return ZSTDnit_checksum;
case ZSTDds_decodeSkippableHeader:
case ZSTDds_skipFrame:
return ZSTDnit_skippableFrame;
}
}
int ZSTD_isSkipFrame(ZSTD_DCtx* dctx) { return dctx->stage == ZSTDds_skipFrame; } /* for zbuff */
/** ZSTD_decompressContinue() :
* @return : nb of bytes generated into `dst` (necessarily <= `dstCapacity)
* or an error code, which can be tested using ZSTD_isError() */
size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
/* Sanity check */
if (srcSize != dctx->expected) return ERROR(srcSize_wrong);
if (dstCapacity) ZSTD_checkContinuity(dctx, dst);
switch (dctx->stage)
{
case ZSTDds_getFrameHeaderSize :
if (srcSize != ZSTD_frameHeaderSize_prefix) return ERROR(srcSize_wrong); /* impossible */
if ((MEM_readLE32(src) & 0xFFFFFFF0U) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */
memcpy(dctx->headerBuffer, src, ZSTD_frameHeaderSize_prefix);
dctx->expected = ZSTD_skippableHeaderSize - ZSTD_frameHeaderSize_prefix; /* magic number + skippable frame length */
dctx->stage = ZSTDds_decodeSkippableHeader;
return 0;
}
dctx->headerSize = ZSTD_frameHeaderSize(src, ZSTD_frameHeaderSize_prefix);
if (ZSTD_isError(dctx->headerSize)) return dctx->headerSize;
memcpy(dctx->headerBuffer, src, ZSTD_frameHeaderSize_prefix);
if (dctx->headerSize > ZSTD_frameHeaderSize_prefix) {
dctx->expected = dctx->headerSize - ZSTD_frameHeaderSize_prefix;
dctx->stage = ZSTDds_decodeFrameHeader;
return 0;
}
dctx->expected = 0; /* not necessary to copy more */
case ZSTDds_decodeFrameHeader:
memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
CHECK_F(ZSTD_decodeFrameHeader(dctx, dctx->headerBuffer, dctx->headerSize));
dctx->expected = ZSTD_blockHeaderSize;
dctx->stage = ZSTDds_decodeBlockHeader;
return 0;
case ZSTDds_decodeBlockHeader:
{ blockProperties_t bp;
size_t const cBlockSize = ZSTD_getcBlockSize(src, ZSTD_blockHeaderSize, &bp);
if (ZSTD_isError(cBlockSize)) return cBlockSize;
dctx->expected = cBlockSize;
dctx->bType = bp.blockType;
dctx->rleSize = bp.origSize;
if (cBlockSize) {
dctx->stage = bp.lastBlock ? ZSTDds_decompressLastBlock : ZSTDds_decompressBlock;
return 0;
}
/* empty block */
if (bp.lastBlock) {
if (dctx->fParams.checksumFlag) {
dctx->expected = 4;
dctx->stage = ZSTDds_checkChecksum;
} else {
dctx->expected = 0; /* end of frame */
dctx->stage = ZSTDds_getFrameHeaderSize;
}
} else {
dctx->expected = 3; /* go directly to next header */
dctx->stage = ZSTDds_decodeBlockHeader;
}
return 0;
}
case ZSTDds_decompressLastBlock:
case ZSTDds_decompressBlock:
{ size_t rSize;
switch(dctx->bType)
{
case bt_compressed:
rSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize);
break;
case bt_raw :
rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize);
break;
case bt_rle :
rSize = ZSTD_setRleBlock(dst, dstCapacity, src, srcSize, dctx->rleSize);
break;
case bt_reserved : /* should never happen */
default:
return ERROR(corruption_detected);
}
if (ZSTD_isError(rSize)) return rSize;
if (dctx->fParams.checksumFlag) XXH64_update(&dctx->xxhState, dst, rSize);
if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of frame */
if (dctx->fParams.checksumFlag) { /* another round for frame checksum */
dctx->expected = 4;
dctx->stage = ZSTDds_checkChecksum;
} else {
dctx->expected = 0; /* ends here */
dctx->stage = ZSTDds_getFrameHeaderSize;
}
} else {
dctx->stage = ZSTDds_decodeBlockHeader;
dctx->expected = ZSTD_blockHeaderSize;
dctx->previousDstEnd = (char*)dst + rSize;
}
return rSize;
}
case ZSTDds_checkChecksum:
{ U32 const h32 = (U32)XXH64_digest(&dctx->xxhState);
U32 const check32 = MEM_readLE32(src); /* srcSize == 4, guaranteed by dctx->expected */
if (check32 != h32) return ERROR(checksum_wrong);
dctx->expected = 0;
dctx->stage = ZSTDds_getFrameHeaderSize;
return 0;
}
case ZSTDds_decodeSkippableHeader:
{ memcpy(dctx->headerBuffer + ZSTD_frameHeaderSize_prefix, src, dctx->expected);
dctx->expected = MEM_readLE32(dctx->headerBuffer + 4);
dctx->stage = ZSTDds_skipFrame;
return 0;
}
case ZSTDds_skipFrame:
{ dctx->expected = 0;
dctx->stage = ZSTDds_getFrameHeaderSize;
return 0;
}
default:
return ERROR(GENERIC); /* impossible */
}
}
static size_t ZSTD_refDictContent(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{
dctx->dictEnd = dctx->previousDstEnd;
dctx->vBase = (const char*)dict - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->base));
dctx->base = dict;
dctx->previousDstEnd = (const char*)dict + dictSize;
return 0;
}
/* ZSTD_loadEntropy() :
* dict : must point at beginning of a valid zstd dictionary
* @return : size of entropy tables read */
static size_t ZSTD_loadEntropy(ZSTD_entropyTables_t* entropy, const void* const dict, size_t const dictSize)
{
const BYTE* dictPtr = (const BYTE*)dict;
const BYTE* const dictEnd = dictPtr + dictSize;
if (dictSize <= 8) return ERROR(dictionary_corrupted);
dictPtr += 8; /* skip header = magic + dictID */
{ size_t const hSize = HUF_readDTableX4(entropy->hufTable, dictPtr, dictEnd-dictPtr);
if (HUF_isError(hSize)) return ERROR(dictionary_corrupted);
dictPtr += hSize;
}
{ short offcodeNCount[MaxOff+1];
U32 offcodeMaxValue = MaxOff, offcodeLog;
size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd-dictPtr);
if (FSE_isError(offcodeHeaderSize)) return ERROR(dictionary_corrupted);
if (offcodeLog > OffFSELog) return ERROR(dictionary_corrupted);
CHECK_E(FSE_buildDTable(entropy->OFTable, offcodeNCount, offcodeMaxValue, offcodeLog), dictionary_corrupted);
dictPtr += offcodeHeaderSize;
}
{ short matchlengthNCount[MaxML+1];
unsigned matchlengthMaxValue = MaxML, matchlengthLog;
size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd-dictPtr);
if (FSE_isError(matchlengthHeaderSize)) return ERROR(dictionary_corrupted);
if (matchlengthLog > MLFSELog) return ERROR(dictionary_corrupted);
CHECK_E(FSE_buildDTable(entropy->MLTable, matchlengthNCount, matchlengthMaxValue, matchlengthLog), dictionary_corrupted);
dictPtr += matchlengthHeaderSize;
}
{ short litlengthNCount[MaxLL+1];
unsigned litlengthMaxValue = MaxLL, litlengthLog;
size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd-dictPtr);
if (FSE_isError(litlengthHeaderSize)) return ERROR(dictionary_corrupted);
if (litlengthLog > LLFSELog) return ERROR(dictionary_corrupted);
CHECK_E(FSE_buildDTable(entropy->LLTable, litlengthNCount, litlengthMaxValue, litlengthLog), dictionary_corrupted);
dictPtr += litlengthHeaderSize;
}
if (dictPtr+12 > dictEnd) return ERROR(dictionary_corrupted);
{ int i;
size_t const dictContentSize = (size_t)(dictEnd - (dictPtr+12));
for (i=0; i<3; i++) {
U32 const rep = MEM_readLE32(dictPtr); dictPtr += 4;
if (rep==0 || rep >= dictContentSize) return ERROR(dictionary_corrupted);
entropy->rep[i] = rep;
} }
return dictPtr - (const BYTE*)dict;
}
static size_t ZSTD_decompress_insertDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{
if (dictSize < 8) return ZSTD_refDictContent(dctx, dict, dictSize);
{ U32 const magic = MEM_readLE32(dict);
if (magic != ZSTD_DICT_MAGIC) {
return ZSTD_refDictContent(dctx, dict, dictSize); /* pure content mode */
} }
dctx->dictID = MEM_readLE32((const char*)dict + 4);
/* load entropy tables */
{ size_t const eSize = ZSTD_loadEntropy(&dctx->entropy, dict, dictSize);
if (ZSTD_isError(eSize)) return ERROR(dictionary_corrupted);
dict = (const char*)dict + eSize;
dictSize -= eSize;
}
dctx->litEntropy = dctx->fseEntropy = 1;
/* reference dictionary content */
return ZSTD_refDictContent(dctx, dict, dictSize);
}
size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize)
{
CHECK_F(ZSTD_decompressBegin(dctx));
if (dict && dictSize) CHECK_E(ZSTD_decompress_insertDictionary(dctx, dict, dictSize), dictionary_corrupted);
return 0;
}
/* ====== ZSTD_DDict ====== */
struct ZSTD_DDict_s {
void* dictBuffer;
const void* dictContent;
size_t dictSize;
ZSTD_entropyTables_t entropy;
U32 dictID;
U32 entropyPresent;
ZSTD_customMem cMem;
}; /* typedef'd to ZSTD_DDict within "zstd.h" */
static const void* ZSTD_DDictDictContent(const ZSTD_DDict* ddict)
{
return ddict->dictContent;
}
static size_t ZSTD_DDictDictSize(const ZSTD_DDict* ddict)
{
return ddict->dictSize;
}
static void ZSTD_refDDict(ZSTD_DCtx* dstDCtx, const ZSTD_DDict* ddict)
{
ZSTD_decompressBegin(dstDCtx); /* init */
if (ddict) { /* support refDDict on NULL */
dstDCtx->dictID = ddict->dictID;
dstDCtx->base = ddict->dictContent;
dstDCtx->vBase = ddict->dictContent;
dstDCtx->dictEnd = (const BYTE*)ddict->dictContent + ddict->dictSize;
dstDCtx->previousDstEnd = dstDCtx->dictEnd;
if (ddict->entropyPresent) {
dstDCtx->litEntropy = 1;
dstDCtx->fseEntropy = 1;
dstDCtx->LLTptr = ddict->entropy.LLTable;
dstDCtx->MLTptr = ddict->entropy.MLTable;
dstDCtx->OFTptr = ddict->entropy.OFTable;
dstDCtx->HUFptr = ddict->entropy.hufTable;
dstDCtx->entropy.rep[0] = ddict->entropy.rep[0];
dstDCtx->entropy.rep[1] = ddict->entropy.rep[1];
dstDCtx->entropy.rep[2] = ddict->entropy.rep[2];
} else {
dstDCtx->litEntropy = 0;
dstDCtx->fseEntropy = 0;
}
}
}
static size_t ZSTD_loadEntropy_inDDict(ZSTD_DDict* ddict)
{
ddict->dictID = 0;
ddict->entropyPresent = 0;
if (ddict->dictSize < 8) return 0;
{ U32 const magic = MEM_readLE32(ddict->dictContent);
if (magic != ZSTD_DICT_MAGIC) return 0; /* pure content mode */
}
ddict->dictID = MEM_readLE32((const char*)ddict->dictContent + 4);
/* load entropy tables */
CHECK_E( ZSTD_loadEntropy(&ddict->entropy, ddict->dictContent, ddict->dictSize), dictionary_corrupted );
ddict->entropyPresent = 1;
return 0;
}
ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize, unsigned byReference, ZSTD_customMem customMem)
{
if (!customMem.customAlloc && !customMem.customFree) customMem = defaultCustomMem;
if (!customMem.customAlloc || !customMem.customFree) return NULL;
{ ZSTD_DDict* const ddict = (ZSTD_DDict*) ZSTD_malloc(sizeof(ZSTD_DDict), customMem);
if (!ddict) return NULL;
ddict->cMem = customMem;
if ((byReference) || (!dict) || (!dictSize)) {
ddict->dictBuffer = NULL;
ddict->dictContent = dict;
} else {
void* const internalBuffer = ZSTD_malloc(dictSize, customMem);
if (!internalBuffer) { ZSTD_freeDDict(ddict); return NULL; }
memcpy(internalBuffer, dict, dictSize);
ddict->dictBuffer = internalBuffer;
ddict->dictContent = internalBuffer;
}
ddict->dictSize = dictSize;
ddict->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover both little and big endian */
/* parse dictionary content */
{ size_t const errorCode = ZSTD_loadEntropy_inDDict(ddict);
if (ZSTD_isError(errorCode)) {
ZSTD_freeDDict(ddict);
return NULL;
} }
return ddict;
}
}
/*! ZSTD_createDDict() :
* Create a digested dictionary, to start decompression without startup delay.
* `dict` content is copied inside DDict.
* Consequently, `dict` can be released after `ZSTD_DDict` creation */
ZSTD_DDict* ZSTD_createDDict(const void* dict, size_t dictSize)
{
ZSTD_customMem const allocator = { NULL, NULL, NULL };
return ZSTD_createDDict_advanced(dict, dictSize, 0, allocator);
}
/*! ZSTD_createDDict_byReference() :
* Create a digested dictionary, to start decompression without startup delay.
* Dictionary content is simply referenced, it will be accessed during decompression.
* Warning : dictBuffer must outlive DDict (DDict must be freed before dictBuffer) */
ZSTD_DDict* ZSTD_createDDict_byReference(const void* dictBuffer, size_t dictSize)
{
ZSTD_customMem const allocator = { NULL, NULL, NULL };
return ZSTD_createDDict_advanced(dictBuffer, dictSize, 1, allocator);
}
size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
{
if (ddict==NULL) return 0; /* support free on NULL */
{ ZSTD_customMem const cMem = ddict->cMem;
ZSTD_free(ddict->dictBuffer, cMem);
ZSTD_free(ddict, cMem);
return 0;
}
}
/*! ZSTD_estimateDDictSize() :
* Estimate amount of memory that will be needed to create a dictionary for decompression.
* Note : if dictionary is created "byReference", reduce this amount by dictSize */
size_t ZSTD_estimateDDictSize(size_t dictSize)
{
return dictSize + sizeof(ZSTD_DDict);
}
size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict)
{
if (ddict==NULL) return 0; /* support sizeof on NULL */
return sizeof(*ddict) + (ddict->dictBuffer ? ddict->dictSize : 0) ;
}
/*! ZSTD_getDictID_fromDict() :
* Provides the dictID stored within dictionary.
* if @return == 0, the dictionary is not conformant with Zstandard specification.
* It can still be loaded, but as a content-only dictionary. */
unsigned ZSTD_getDictID_fromDict(const void* dict, size_t dictSize)
{
if (dictSize < 8) return 0;
if (MEM_readLE32(dict) != ZSTD_DICT_MAGIC) return 0;
return MEM_readLE32((const char*)dict + 4);
}
/*! ZSTD_getDictID_fromDDict() :
* Provides the dictID of the dictionary loaded into `ddict`.
* If @return == 0, the dictionary is not conformant to Zstandard specification, or empty.
* Non-conformant dictionaries can still be loaded, but as content-only dictionaries. */
unsigned ZSTD_getDictID_fromDDict(const ZSTD_DDict* ddict)
{
if (ddict==NULL) return 0;
return ZSTD_getDictID_fromDict(ddict->dictContent, ddict->dictSize);
}
/*! ZSTD_getDictID_fromFrame() :
* Provides the dictID required to decompresse frame stored within `src`.
* If @return == 0, the dictID could not be decoded.
* This could for one of the following reasons :
* - The frame does not require a dictionary (most common case).
* - The frame was built with dictID intentionally removed.
* Needed dictionary is a hidden information.
* Note : this use case also happens when using a non-conformant dictionary.
* - `srcSize` is too small, and as a result, frame header could not be decoded.
* Note : possible if `srcSize < ZSTD_FRAMEHEADERSIZE_MAX`.
* - This is not a Zstandard frame.
* When identifying the exact failure cause, it's possible to use
* ZSTD_getFrameHeader(), which will provide a more precise error code. */
unsigned ZSTD_getDictID_fromFrame(const void* src, size_t srcSize)
{
ZSTD_frameHeader zfp = { 0 , 0 , 0 , 0 };
size_t const hError = ZSTD_getFrameHeader(&zfp, src, srcSize);
if (ZSTD_isError(hError)) return 0;
return zfp.dictID;
}
/*! ZSTD_decompress_usingDDict() :
* Decompression using a pre-digested Dictionary
* Use dictionary without significant overhead. */
size_t ZSTD_decompress_usingDDict(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize,
const ZSTD_DDict* ddict)
{
/* pass content and size in case legacy frames are encountered */
return ZSTD_decompressMultiFrame(dctx, dst, dstCapacity, src, srcSize,
NULL, 0,
ddict);
}
/*=====================================
* Streaming decompression
*====================================*/
typedef enum { zdss_init, zdss_loadHeader,
zdss_read, zdss_load, zdss_flush } ZSTD_dStreamStage;
/* *** Resource management *** */
struct ZSTD_DStream_s {
ZSTD_DCtx* dctx;
ZSTD_DDict* ddictLocal;
const ZSTD_DDict* ddict;
ZSTD_frameHeader fParams;
ZSTD_dStreamStage stage;
char* inBuff;
size_t inBuffSize;
size_t inPos;
size_t maxWindowSize;
char* outBuff;
size_t outBuffSize;
size_t outStart;
size_t outEnd;
size_t blockSize;
BYTE headerBuffer[ZSTD_FRAMEHEADERSIZE_MAX]; /* tmp buffer to store frame header */
size_t lhSize;
ZSTD_customMem customMem;
void* legacyContext;
U32 previousLegacyVersion;
U32 legacyVersion;
U32 hostageByte;
}; /* typedef'd to ZSTD_DStream within "zstd.h" */
ZSTD_DStream* ZSTD_createDStream(void)
{
return ZSTD_createDStream_advanced(defaultCustomMem);
}
ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem)
{
ZSTD_DStream* zds;
if (!customMem.customAlloc && !customMem.customFree) customMem = defaultCustomMem;
if (!customMem.customAlloc || !customMem.customFree) return NULL;
zds = (ZSTD_DStream*) ZSTD_malloc(sizeof(ZSTD_DStream), customMem);
if (zds==NULL) return NULL;
memset(zds, 0, sizeof(ZSTD_DStream));
memcpy(&zds->customMem, &customMem, sizeof(ZSTD_customMem));
zds->dctx = ZSTD_createDCtx_advanced(customMem);
if (zds->dctx == NULL) { ZSTD_freeDStream(zds); return NULL; }
zds->stage = zdss_init;
zds->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT;
return zds;
}
size_t ZSTD_freeDStream(ZSTD_DStream* zds)
{
if (zds==NULL) return 0; /* support free on null */
{ ZSTD_customMem const cMem = zds->customMem;
ZSTD_freeDCtx(zds->dctx);
zds->dctx = NULL;
ZSTD_freeDDict(zds->ddictLocal);
zds->ddictLocal = NULL;
ZSTD_free(zds->inBuff, cMem);
zds->inBuff = NULL;
ZSTD_free(zds->outBuff, cMem);
zds->outBuff = NULL;
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1)
if (zds->legacyContext)
ZSTD_freeLegacyStreamContext(zds->legacyContext, zds->previousLegacyVersion);
#endif
ZSTD_free(zds, cMem);
return 0;
}
}
/* *** Initialization *** */
size_t ZSTD_DStreamInSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX + ZSTD_blockHeaderSize; }
size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_ABSOLUTEMAX; }
size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize)
{
zds->stage = zdss_loadHeader;
zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
ZSTD_freeDDict(zds->ddictLocal);
if (dict && dictSize >= 8) {
zds->ddictLocal = ZSTD_createDDict(dict, dictSize);
if (zds->ddictLocal == NULL) return ERROR(memory_allocation);
} else zds->ddictLocal = NULL;
zds->ddict = zds->ddictLocal;
zds->legacyVersion = 0;
zds->hostageByte = 0;
return ZSTD_frameHeaderSize_prefix;
}
size_t ZSTD_initDStream(ZSTD_DStream* zds)
{
return ZSTD_initDStream_usingDict(zds, NULL, 0);
}
/* ZSTD_initDStream_usingDDict() :
* ddict will just be referenced, and must outlive decompression session */
size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict)
{
size_t const initResult = ZSTD_initDStream(zds);
zds->ddict = ddict;
return initResult;
}
size_t ZSTD_resetDStream(ZSTD_DStream* zds)
{
zds->stage = zdss_loadHeader;
zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0;
zds->legacyVersion = 0;
zds->hostageByte = 0;
return ZSTD_frameHeaderSize_prefix;
}
size_t ZSTD_setDStreamParameter(ZSTD_DStream* zds,
ZSTD_DStreamParameter_e paramType, unsigned paramValue)
{
switch(paramType)
{
default : return ERROR(parameter_unknown);
case DStream_p_maxWindowSize : zds->maxWindowSize = paramValue ? paramValue : (U32)(-1); break;
}
return 0;
}
size_t ZSTD_sizeof_DStream(const ZSTD_DStream* zds)
{
if (zds==NULL) return 0; /* support sizeof NULL */
return sizeof(*zds)
+ ZSTD_sizeof_DCtx(zds->dctx)
+ ZSTD_sizeof_DDict(zds->ddictLocal)
+ zds->inBuffSize + zds->outBuffSize;
}
size_t ZSTD_estimateDStreamSize(ZSTD_frameHeader fHeader)
{
size_t const windowSize = fHeader.windowSize;
size_t const blockSize = MIN(windowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
size_t const inBuffSize = blockSize; /* no block can be larger */
size_t const outBuffSize = windowSize + blockSize + (WILDCOPY_OVERLENGTH * 2);
return sizeof(ZSTD_DStream) + ZSTD_estimateDCtxSize() + inBuffSize + outBuffSize;
}
/* ***** Decompression ***** */
MEM_STATIC size_t ZSTD_limitCopy(void* dst, size_t dstCapacity, const void* src, size_t srcSize)
{
size_t const length = MIN(dstCapacity, srcSize);
memcpy(dst, src, length);
return length;
}
size_t ZSTD_decompressStream(ZSTD_DStream* zds, ZSTD_outBuffer* output, ZSTD_inBuffer* input)
{
const char* const istart = (const char*)(input->src) + input->pos;
const char* const iend = (const char*)(input->src) + input->size;
const char* ip = istart;
char* const ostart = (char*)(output->dst) + output->pos;
char* const oend = (char*)(output->dst) + output->size;
char* op = ostart;
U32 someMoreWork = 1;
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
if (zds->legacyVersion)
return ZSTD_decompressLegacyStream(zds->legacyContext, zds->legacyVersion, output, input);
#endif
while (someMoreWork) {
switch(zds->stage)
{
case zdss_init :
ZSTD_resetDStream(zds); /* transparent reset on starting decoding a new frame */
/* fall-through */
case zdss_loadHeader :
{ size_t const hSize = ZSTD_getFrameHeader(&zds->fParams, zds->headerBuffer, zds->lhSize);
if (ZSTD_isError(hSize))
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1)
{ U32 const legacyVersion = ZSTD_isLegacy(istart, iend-istart);
if (legacyVersion) {
const void* const dict = zds->ddict ? zds->ddict->dictContent : NULL;
size_t const dictSize = zds->ddict ? zds->ddict->dictSize : 0;
CHECK_F(ZSTD_initLegacyStream(&zds->legacyContext, zds->previousLegacyVersion, legacyVersion,
dict, dictSize));
zds->legacyVersion = zds->previousLegacyVersion = legacyVersion;
return ZSTD_decompressLegacyStream(zds->legacyContext, zds->legacyVersion, output, input);
} else {
return hSize; /* error */
} }
#else
return hSize;
#endif
if (hSize != 0) { /* need more input */
size_t const toLoad = hSize - zds->lhSize; /* if hSize!=0, hSize > zds->lhSize */
if (toLoad > (size_t)(iend-ip)) { /* not enough input to load full header */
memcpy(zds->headerBuffer + zds->lhSize, ip, iend-ip);
zds->lhSize += iend-ip;
input->pos = input->size;
return (MAX(ZSTD_frameHeaderSize_min, hSize) - zds->lhSize) + ZSTD_blockHeaderSize; /* remaining header bytes + next block header */
}
memcpy(zds->headerBuffer + zds->lhSize, ip, toLoad); zds->lhSize = hSize; ip += toLoad;
break;
} }
/* check for single-pass mode opportunity */
if (zds->fParams.frameContentSize && zds->fParams.windowSize /* skippable frame if == 0 */
&& (U64)(size_t)(oend-op) >= zds->fParams.frameContentSize) {
size_t const cSize = ZSTD_findFrameCompressedSize(istart, iend-istart);
if (cSize <= (size_t)(iend-istart)) {
size_t const decompressedSize = ZSTD_decompress_usingDDict(zds->dctx, op, oend-op, istart, cSize, zds->ddict);
if (ZSTD_isError(decompressedSize)) return decompressedSize;
ip = istart + cSize;
op += decompressedSize;
zds->dctx->expected = 0;
zds->stage = zdss_init;
someMoreWork = 0;
break;
} }
/* Consume header */
ZSTD_refDDict(zds->dctx, zds->ddict);
{ size_t const h1Size = ZSTD_nextSrcSizeToDecompress(zds->dctx); /* == ZSTD_frameHeaderSize_prefix */
CHECK_F(ZSTD_decompressContinue(zds->dctx, NULL, 0, zds->headerBuffer, h1Size));
{ size_t const h2Size = ZSTD_nextSrcSizeToDecompress(zds->dctx);
CHECK_F(ZSTD_decompressContinue(zds->dctx, NULL, 0, zds->headerBuffer+h1Size, h2Size));
} }
zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN);
if (zds->fParams.windowSize > zds->maxWindowSize) return ERROR(frameParameter_windowTooLarge);
/* Adapt buffer sizes to frame header instructions */
{ size_t const blockSize = MIN(zds->fParams.windowSize, ZSTD_BLOCKSIZE_ABSOLUTEMAX);
size_t const neededOutSize = zds->fParams.windowSize + blockSize + WILDCOPY_OVERLENGTH * 2;
zds->blockSize = blockSize;
if (zds->inBuffSize < blockSize) {
ZSTD_free(zds->inBuff, zds->customMem);
zds->inBuffSize = 0;
zds->inBuff = (char*)ZSTD_malloc(blockSize, zds->customMem);
if (zds->inBuff == NULL) return ERROR(memory_allocation);
zds->inBuffSize = blockSize;
}
if (zds->outBuffSize < neededOutSize) {
ZSTD_free(zds->outBuff, zds->customMem);
zds->outBuffSize = 0;
zds->outBuff = (char*)ZSTD_malloc(neededOutSize, zds->customMem);
if (zds->outBuff == NULL) return ERROR(memory_allocation);
zds->outBuffSize = neededOutSize;
} }
zds->stage = zdss_read;
/* pass-through */
case zdss_read:
{ size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
if (neededInSize==0) { /* end of frame */
zds->stage = zdss_init;
someMoreWork = 0;
break;
}
if ((size_t)(iend-ip) >= neededInSize) { /* decode directly from src */
const int isSkipFrame = ZSTD_isSkipFrame(zds->dctx);
size_t const decodedSize = ZSTD_decompressContinue(zds->dctx,
zds->outBuff + zds->outStart, (isSkipFrame ? 0 : zds->outBuffSize - zds->outStart),
ip, neededInSize);
if (ZSTD_isError(decodedSize)) return decodedSize;
ip += neededInSize;
if (!decodedSize && !isSkipFrame) break; /* this was just a header */
zds->outEnd = zds->outStart + decodedSize;
zds->stage = zdss_flush;
break;
}
if (ip==iend) { someMoreWork = 0; break; } /* no more input */
zds->stage = zdss_load;
/* pass-through */
}
case zdss_load:
{ size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds->dctx);
size_t const toLoad = neededInSize - zds->inPos; /* should always be <= remaining space within inBuff */
size_t loadedSize;
if (toLoad > zds->inBuffSize - zds->inPos) return ERROR(corruption_detected); /* should never happen */
loadedSize = ZSTD_limitCopy(zds->inBuff + zds->inPos, toLoad, ip, iend-ip);
ip += loadedSize;
zds->inPos += loadedSize;
if (loadedSize < toLoad) { someMoreWork = 0; break; } /* not enough input, wait for more */
/* decode loaded input */
{ const int isSkipFrame = ZSTD_isSkipFrame(zds->dctx);
size_t const decodedSize = ZSTD_decompressContinue(zds->dctx,
zds->outBuff + zds->outStart, zds->outBuffSize - zds->outStart,
zds->inBuff, neededInSize);
if (ZSTD_isError(decodedSize)) return decodedSize;
zds->inPos = 0; /* input is consumed */
if (!decodedSize && !isSkipFrame) { zds->stage = zdss_read; break; } /* this was just a header */
zds->outEnd = zds->outStart + decodedSize;
zds->stage = zdss_flush;
/* pass-through */
} }
case zdss_flush:
{ size_t const toFlushSize = zds->outEnd - zds->outStart;
size_t const flushedSize = ZSTD_limitCopy(op, oend-op, zds->outBuff + zds->outStart, toFlushSize);
op += flushedSize;
zds->outStart += flushedSize;
if (flushedSize == toFlushSize) { /* flush completed */
zds->stage = zdss_read;
if (zds->outStart + zds->blockSize > zds->outBuffSize)
zds->outStart = zds->outEnd = 0;
break;
}
/* cannot complete flush */
someMoreWork = 0;
break;
}
default: return ERROR(GENERIC); /* impossible */
} }
/* result */
input->pos += (size_t)(ip-istart);
output->pos += (size_t)(op-ostart);
{ size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zds->dctx);
if (!nextSrcSizeHint) { /* frame fully decoded */
if (zds->outEnd == zds->outStart) { /* output fully flushed */
if (zds->hostageByte) {
if (input->pos >= input->size) { zds->stage = zdss_read; return 1; } /* can't release hostage (not present) */
input->pos++; /* release hostage */
}
return 0;
}
if (!zds->hostageByte) { /* output not fully flushed; keep last byte as hostage; will be released when all output is flushed */
input->pos--; /* note : pos > 0, otherwise, impossible to finish reading last block */
zds->hostageByte=1;
}
return 1;
}
nextSrcSizeHint += ZSTD_blockHeaderSize * (ZSTD_nextInputType(zds->dctx) == ZSTDnit_block); /* preload header of next block */
if (zds->inPos > nextSrcSizeHint) return ERROR(GENERIC); /* should never happen */
nextSrcSizeHint -= zds->inPos; /* already loaded*/
return nextSrcSizeHint;
}
}
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