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util: expose an "available" API on compression engines...
util: expose an "available" API on compression engines When the zstd compression engine is introduced, it won't work in all installations, namely pure Python installs. So, we need a mechanism to declare whether a compression engine is available. We don't want to conditionally register the compression engine because it is sometimes useful to know when a compression engine name or encountered data is valid but just not available versus unknown.
Gregory Szorc - - Load All Authors

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zstd_decompress.c
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/ contrib / python-zstandard / zstd / 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 XXH_STATIC_LINKING_ONLY /* XXH64_state_t */
#include "xxhash.h" /* XXH64_* */
#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
/*-*************************************
* 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;
struct ZSTD_DCtx_s
{
const FSE_DTable* LLTptr;
const FSE_DTable* MLTptr;
const FSE_DTable* OFTptr;
const HUF_DTable* HUFptr;
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 */
const void* previousDstEnd;
const void* base;
const void* vBase;
const void* dictEnd;
size_t expected;
U32 rep[ZSTD_REP_NUM];
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;
XXH64_state_t xxhState;
size_t headerSize;
U32 dictID;
const BYTE* litPtr;
ZSTD_customMem customMem;
size_t litBufSize;
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->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->rep) == sizeof(repStartValue));
memcpy(dctx->rep, repStartValue, sizeof(repStartValue)); /* initial repcodes */
dctx->LLTptr = dctx->LLTable;
dctx->MLTptr = dctx->MLTable;
dctx->OFTptr = dctx->OFTable;
dctx->HUFptr = dctx->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_refDCtx(ZSTD_DCtx* dstDCtx, const ZSTD_DCtx* srcDCtx)
{
ZSTD_decompressBegin(dstDCtx); /* init */
if (srcDCtx) { /* support refDCtx on NULL */
dstDCtx->dictEnd = srcDCtx->dictEnd;
dstDCtx->vBase = srcDCtx->vBase;
dstDCtx->base = srcDCtx->base;
dstDCtx->previousDstEnd = srcDCtx->previousDstEnd;
dstDCtx->dictID = srcDCtx->dictID;
dstDCtx->litEntropy = srcDCtx->litEntropy;
dstDCtx->fseEntropy = srcDCtx->fseEntropy;
dstDCtx->LLTptr = srcDCtx->LLTable;
dstDCtx->MLTptr = srcDCtx->MLTable;
dstDCtx->OFTptr = srcDCtx->OFTable;
dstDCtx->HUFptr = srcDCtx->hufTable;
dstDCtx->rep[0] = srcDCtx->rep[0];
dstDCtx->rep[1] = srcDCtx->rep[1];
dstDCtx->rep[2] = srcDCtx->rep[2];
}
}
/*-*************************************************************
* Decompression section
***************************************************************/
/* See compression format details in : doc/zstd_compression_format.md */
/** 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 (MEM_readLE32(src) != ZSTD_MAGICNUMBER) {
if ((MEM_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 = MEM_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 = 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);
fparamsPtr->frameContentSize = frameContentSize;
fparamsPtr->windowSize = windowSize;
fparamsPtr->dictID = dictID;
fparamsPtr->checksumFlag = checksumFlag;
}
return 0;
}
/** 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)
{
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT==1)
if (ZSTD_isLegacy(src, srcSize)) return ZSTD_getDecompressedSize_legacy(src, srcSize);
#endif
{ ZSTD_frameParams fparams;
size_t const frResult = ZSTD_getFrameParams(&fparams, src, srcSize);
if (frResult!=0) return 0;
return fparams.frameContentSize;
}
}
/** 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 = 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->hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize) :
HUF_decompress4X_hufOnly (dctx->hufTable, dctx->litBuffer, litSize, istart+lhSize, litCSize)) ))
return ERROR(corruption_detected);
dctx->litPtr = dctx->litBuffer;
dctx->litBufSize = ZSTD_BLOCKSIZE_ABSOLUTEMAX+WILDCOPY_OVERLENGTH;
dctx->litSize = litSize;
dctx->litEntropy = 1;
if (litEncType==set_compressed) dctx->HUFptr = dctx->hufTable;
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->litBufSize = ZSTD_BLOCKSIZE_ABSOLUTEMAX+8;
dctx->litSize = litSize;
return lhSize+litSize;
}
/* direct reference into compressed stream */
dctx->litPtr = istart+lhSize;
dctx->litBufSize = srcSize-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);
dctx->litPtr = dctx->litBuffer;
dctx->litBufSize = ZSTD_BLOCKSIZE_ABSOLUTEMAX+WILDCOPY_OVERLENGTH;
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)
{
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->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->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->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;
} 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];
} seqState_t;
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_readBits(&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_readBits(&seqState->DStream, mlBits) : 0); /* <= 16 bits */
if (MEM_32bits() && (mlBits+llBits>24)) BIT_reloadDStream(&seqState->DStream);
seq.litLength = LL_base[llCode] + ((llCode>15) ? BIT_readBits(&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_NOINLINE
size_t ZSTD_execSequenceLast7(BYTE* op,
BYTE* const oend, seq_t sequence,
const BYTE** litPtr, const BYTE* const litLimit_w,
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_w) 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;
}
FORCE_INLINE
size_t ZSTD_execSequence(BYTE* op,
BYTE* const oend, seq_t sequence,
const BYTE** litPtr, const BYTE* const litLimit_w,
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_w) return ERROR(corruption_detected); /* over-read beyond lit buffer */
if (oLitEnd>oend_w) return ZSTD_execSequenceLast7(op, oend, sequence, litPtr, litLimit_w, 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 */
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;
if (op > oend_w) {
U32 i;
for (i = 0; i < sequence.matchLength; ++i) op[i] = match[i];
return sequenceLength;
}
} }
/* Requirement: op <= oend_w */
/* 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 }; /* substracted */
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, 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 litLimit_w = litPtr + dctx->litBufSize - WILDCOPY_OVERLENGTH;
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->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, litLimit_w, 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->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 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;
}
}
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 sub-block */
{ size_t const litCSize = ZSTD_decodeLiteralsBlock(dctx, src, srcSize);
if (ZSTD_isError(litCSize)) return litCSize;
ip += litCSize;
srcSize -= litCSize;
}
return ZSTD_decompressSequences(dctx, dst, dstCapacity, ip, srcSize);
}
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_decompressFrame() :
* `dctx` must be properly initialized */
static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
void* dst, size_t dstCapacity,
const void* src, size_t srcSize)
{
const BYTE* ip = (const BYTE*)src;
BYTE* const ostart = (BYTE* const)dst;
BYTE* const oend = ostart + dstCapacity;
BYTE* op = ostart;
size_t remainingSize = srcSize;
/* check */
if (srcSize < ZSTD_frameHeaderSize_min+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
/* Frame Header */
{ size_t const frameHeaderSize = ZSTD_frameHeaderSize(src, ZSTD_frameHeaderSize_prefix);
if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize;
if (srcSize < frameHeaderSize+ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
CHECK_F(ZSTD_decodeFrameHeader(dctx, src, 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);
remainingSize -= 4;
}
if (remainingSize) return ERROR(srcSize_wrong);
return op-ostart;
}
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)
{
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT==1)
if (ZSTD_isLegacy(src, srcSize)) return ZSTD_decompressLegacy(dst, dstCapacity, src, srcSize, dict, dictSize);
#endif
ZSTD_decompressBegin_usingDict(dctx, dict, dictSize);
ZSTD_checkContinuity(dctx, dst);
return ZSTD_decompressFrame(dctx, dst, dstCapacity, src, srcSize);
}
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;
}
static size_t ZSTD_loadEntropy(ZSTD_DCtx* dctx, const void* const dict, size_t const dictSize)
{
const BYTE* dictPtr = (const BYTE*)dict;
const BYTE* const dictEnd = dictPtr + dictSize;
{ size_t const hSize = HUF_readDTableX4(dctx->hufTable, dict, dictSize);
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(dctx->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(dctx->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(dctx->LLTable, litlengthNCount, litlengthMaxValue, litlengthLog), dictionary_corrupted);
dictPtr += litlengthHeaderSize;
}
if (dictPtr+12 > dictEnd) return ERROR(dictionary_corrupted);
dctx->rep[0] = MEM_readLE32(dictPtr+0); if (dctx->rep[0] >= dictSize) return ERROR(dictionary_corrupted);
dctx->rep[1] = MEM_readLE32(dictPtr+4); if (dctx->rep[1] >= dictSize) return ERROR(dictionary_corrupted);
dctx->rep[2] = MEM_readLE32(dictPtr+8); if (dctx->rep[2] >= dictSize) return ERROR(dictionary_corrupted);
dictPtr += 12;
dctx->litEntropy = dctx->fseEntropy = 1;
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 */
dict = (const char*)dict + 8;
dictSize -= 8;
{ size_t const eSize = ZSTD_loadEntropy(dctx, dict, dictSize);
if (ZSTD_isError(eSize)) return ERROR(dictionary_corrupted);
dict = (const char*)dict + eSize;
dictSize -= eSize;
}
/* 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* dict;
size_t dictSize;
ZSTD_DCtx* refContext;
}; /* typedef'd to ZSTD_DDict within "zstd.h" */
ZSTD_DDict* ZSTD_createDDict_advanced(const void* dict, size_t dictSize, 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);
void* const dictContent = ZSTD_malloc(dictSize, customMem);
ZSTD_DCtx* const dctx = ZSTD_createDCtx_advanced(customMem);
if (!dictContent || !ddict || !dctx) {
ZSTD_free(dictContent, customMem);
ZSTD_free(ddict, customMem);
ZSTD_free(dctx, customMem);
return NULL;
}
if (dictSize) {
memcpy(dictContent, dict, dictSize);
}
{ size_t const errorCode = ZSTD_decompressBegin_usingDict(dctx, dictContent, dictSize);
if (ZSTD_isError(errorCode)) {
ZSTD_free(dictContent, customMem);
ZSTD_free(ddict, customMem);
ZSTD_free(dctx, customMem);
return NULL;
} }
ddict->dict = dictContent;
ddict->dictSize = dictSize;
ddict->refContext = dctx;
return ddict;
}
}
/*! ZSTD_createDDict() :
* Create a digested dictionary, ready to start decompression without startup delay.
* `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, allocator);
}
size_t ZSTD_freeDDict(ZSTD_DDict* ddict)
{
if (ddict==NULL) return 0; /* support free on NULL */
{ ZSTD_customMem const cMem = ddict->refContext->customMem;
ZSTD_freeDCtx(ddict->refContext);
ZSTD_free(ddict->dict, cMem);
ZSTD_free(ddict, cMem);
return 0;
}
}
size_t ZSTD_sizeof_DDict(const ZSTD_DDict* ddict)
{
if (ddict==NULL) return 0; /* support sizeof on NULL */
return sizeof(*ddict) + sizeof(ddict->refContext) + ddict->dictSize;
}
/*! 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)
{
#if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT==1)
if (ZSTD_isLegacy(src, srcSize)) return ZSTD_decompressLegacy(dst, dstCapacity, src, srcSize, ddict->dict, ddict->dictSize);
#endif
ZSTD_refDCtx(dctx, ddict->refContext);
ZSTD_checkContinuity(dctx, dst);
return ZSTD_decompressFrame(dctx, dst, dstCapacity, src, srcSize);
}
/*=====================================
* 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_frameParams 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);
ZSTD_freeDDict(zds->ddictLocal);
ZSTD_free(zds->inBuff, cMem);
ZSTD_free(zds->outBuff, cMem);
#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) {
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);
}
size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* zds, const ZSTD_DDict* ddict) /**< note : ddict will just be referenced, and must outlive decompression session */
{
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 ZSTDdsp_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 on NULL */
return sizeof(*zds) + ZSTD_sizeof_DCtx(zds->dctx) + ZSTD_sizeof_DDict(zds->ddictLocal) + zds->inBuffSize + zds->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 :
return ERROR(init_missing);
case zdss_loadHeader :
{ size_t const hSize = ZSTD_getFrameParams(&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->dict : 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;
} }
/* Consume header */
{ const ZSTD_DCtx* refContext = zds->ddict ? zds->ddict->refContext : NULL;
ZSTD_refDCtx(zds->dctx, refContext);
}
{ 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;
zds->blockSize = blockSize;
if (zds->inBuffSize < blockSize) {
ZSTD_free(zds->inBuff, zds->customMem);
zds->inBuffSize = blockSize;
zds->inBuff = (char*)ZSTD_malloc(blockSize, zds->customMem);
if (zds->inBuff == NULL) return ERROR(memory_allocation);
}
if (zds->outBuffSize < neededOutSize) {
ZSTD_free(zds->outBuff, zds->customMem);
zds->outBuffSize = neededOutSize;
zds->outBuff = (char*)ZSTD_malloc(neededOutSize, zds->customMem);
if (zds->outBuff == NULL) return ERROR(memory_allocation);
} }
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;
}
}