Mercurial > hg
view contrib/python-zstandard/zstd/decompress/zstd_decompress.c @ 45234:595307e14140
commitctx: move `writechangesetcopy` business at the end a code section
This code is to handle a specific subcase so we move it a the end. This allow
to gather the rest of the "core" code closer to the related logic.
| author | Pierre-Yves David <pierre-yves.david@octobus.net> |
|---|---|
| date | Thu, 23 Jul 2020 22:58:29 +0200 |
| parents | de7838053207 |
| children |
line wrap: on
line source
/* * Copyright (c) 2016-present, Yann Collet, Facebook, Inc. * All rights reserved. * * This source code is licensed under both the BSD-style license (found in the * LICENSE file in the root directory of this source tree) and the GPLv2 (found * in the COPYING file in the root directory of this source tree). * You may select, at your option, one of the above-listed licenses. */ /* *************************************************************** * Tuning parameters *****************************************************************/ /*! * HEAPMODE : * Select how default decompression function ZSTD_decompress() allocates its context, * on stack (0), or into heap (1, default; requires malloc()). * Note that functions with explicit context such as ZSTD_decompressDCtx() are unaffected. */ #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. * It's possible to set a different limit using ZSTD_DCtx_setMaxWindowSize(). */ #ifndef ZSTD_MAXWINDOWSIZE_DEFAULT # define ZSTD_MAXWINDOWSIZE_DEFAULT (((U32)1 << ZSTD_WINDOWLOG_LIMIT_DEFAULT) + 1) #endif /*! * NO_FORWARD_PROGRESS_MAX : * maximum allowed nb of calls to ZSTD_decompressStream() * without any forward progress * (defined as: no byte read from input, and no byte flushed to output) * before triggering an error. */ #ifndef ZSTD_NO_FORWARD_PROGRESS_MAX # define ZSTD_NO_FORWARD_PROGRESS_MAX 16 #endif /*-******************************************************* * Dependencies *********************************************************/ #include <string.h> /* memcpy, memmove, memset */ #include "cpu.h" /* bmi2 */ #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" /* blockProperties_t */ #include "zstd_decompress_internal.h" /* ZSTD_DCtx */ #include "zstd_ddict.h" /* ZSTD_DDictDictContent */ #include "zstd_decompress_block.h" /* ZSTD_decompressBlock_internal */ #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) # include "zstd_legacy.h" #endif /*-************************************************************* * Context management ***************************************************************/ size_t ZSTD_sizeof_DCtx (const ZSTD_DCtx* dctx) { if (dctx==NULL) return 0; /* support sizeof NULL */ return sizeof(*dctx) + ZSTD_sizeof_DDict(dctx->ddictLocal) + dctx->inBuffSize + dctx->outBuffSize; } size_t ZSTD_estimateDCtxSize(void) { return sizeof(ZSTD_DCtx); } static size_t ZSTD_startingInputLength(ZSTD_format_e format) { size_t const startingInputLength = ZSTD_FRAMEHEADERSIZE_PREFIX(format); /* only supports formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless */ assert( (format == ZSTD_f_zstd1) || (format == ZSTD_f_zstd1_magicless) ); return startingInputLength; } static void ZSTD_initDCtx_internal(ZSTD_DCtx* dctx) { dctx->format = ZSTD_f_zstd1; /* ZSTD_decompressBegin() invokes ZSTD_startingInputLength() with argument dctx->format */ dctx->staticSize = 0; dctx->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT; dctx->ddict = NULL; dctx->ddictLocal = NULL; dctx->dictEnd = NULL; dctx->ddictIsCold = 0; dctx->dictUses = ZSTD_dont_use; dctx->inBuff = NULL; dctx->inBuffSize = 0; dctx->outBuffSize = 0; dctx->streamStage = zdss_init; dctx->legacyContext = NULL; dctx->previousLegacyVersion = 0; dctx->noForwardProgress = 0; dctx->bmi2 = ZSTD_cpuid_bmi2(ZSTD_cpuid()); } ZSTD_DCtx* ZSTD_initStaticDCtx(void *workspace, size_t workspaceSize) { ZSTD_DCtx* const dctx = (ZSTD_DCtx*) workspace; if ((size_t)workspace & 7) return NULL; /* 8-aligned */ if (workspaceSize < sizeof(ZSTD_DCtx)) return NULL; /* minimum size */ ZSTD_initDCtx_internal(dctx); dctx->staticSize = workspaceSize; dctx->inBuff = (char*)(dctx+1); return dctx; } ZSTD_DCtx* ZSTD_createDCtx_advanced(ZSTD_customMem customMem) { if (!customMem.customAlloc ^ !customMem.customFree) return NULL; { ZSTD_DCtx* const dctx = (ZSTD_DCtx*)ZSTD_malloc(sizeof(*dctx), customMem); if (!dctx) return NULL; dctx->customMem = customMem; ZSTD_initDCtx_internal(dctx); return dctx; } } ZSTD_DCtx* ZSTD_createDCtx(void) { DEBUGLOG(3, "ZSTD_createDCtx"); return ZSTD_createDCtx_advanced(ZSTD_defaultCMem); } static void ZSTD_clearDict(ZSTD_DCtx* dctx) { ZSTD_freeDDict(dctx->ddictLocal); dctx->ddictLocal = NULL; dctx->ddict = NULL; dctx->dictUses = ZSTD_dont_use; } size_t ZSTD_freeDCtx(ZSTD_DCtx* dctx) { if (dctx==NULL) return 0; /* support free on NULL */ RETURN_ERROR_IF(dctx->staticSize, memory_allocation, "not compatible with static DCtx"); { ZSTD_customMem const cMem = dctx->customMem; ZSTD_clearDict(dctx); ZSTD_free(dctx->inBuff, cMem); dctx->inBuff = NULL; #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1) if (dctx->legacyContext) ZSTD_freeLegacyStreamContext(dctx->legacyContext, dctx->previousLegacyVersion); #endif ZSTD_free(dctx, cMem); return 0; } } /* no longer useful */ void ZSTD_copyDCtx(ZSTD_DCtx* dstDCtx, const ZSTD_DCtx* srcDCtx) { size_t const toCopy = (size_t)((char*)(&dstDCtx->inBuff) - (char*)dstDCtx); memcpy(dstDCtx, srcDCtx, toCopy); /* no need to copy workspace */ } /*-************************************************************* * Frame header decoding ***************************************************************/ /*! 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 < ZSTD_FRAMEIDSIZE) return 0; { U32 const magic = MEM_readLE32(buffer); if (magic == ZSTD_MAGICNUMBER) return 1; if ((magic & ZSTD_MAGIC_SKIPPABLE_MASK) == 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_internal() : * srcSize must be large enough to reach header size fields. * note : only works for formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless. * @return : size of the Frame Header * or an error code, which can be tested with ZSTD_isError() */ static size_t ZSTD_frameHeaderSize_internal(const void* src, size_t srcSize, ZSTD_format_e format) { size_t const minInputSize = ZSTD_startingInputLength(format); RETURN_ERROR_IF(srcSize < minInputSize, srcSize_wrong); { BYTE const fhd = ((const BYTE*)src)[minInputSize-1]; U32 const dictID= fhd & 3; U32 const singleSegment = (fhd >> 5) & 1; U32 const fcsId = fhd >> 6; return minInputSize + !singleSegment + ZSTD_did_fieldSize[dictID] + ZSTD_fcs_fieldSize[fcsId] + (singleSegment && !fcsId); } } /** ZSTD_frameHeaderSize() : * srcSize must be >= ZSTD_frameHeaderSize_prefix. * @return : size of the Frame Header, * or an error code (if srcSize is too small) */ size_t ZSTD_frameHeaderSize(const void* src, size_t srcSize) { return ZSTD_frameHeaderSize_internal(src, srcSize, ZSTD_f_zstd1); } /** ZSTD_getFrameHeader_advanced() : * decode Frame Header, or require larger `srcSize`. * note : only works for formats ZSTD_f_zstd1 and ZSTD_f_zstd1_magicless * @return : 0, `zfhPtr` is correctly filled, * >0, `srcSize` is too small, value is wanted `srcSize` amount, * or an error code, which can be tested using ZSTD_isError() */ size_t ZSTD_getFrameHeader_advanced(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize, ZSTD_format_e format) { const BYTE* ip = (const BYTE*)src; size_t const minInputSize = ZSTD_startingInputLength(format); memset(zfhPtr, 0, sizeof(*zfhPtr)); /* not strictly necessary, but static analyzer do not understand that zfhPtr is only going to be read only if return value is zero, since they are 2 different signals */ if (srcSize < minInputSize) return minInputSize; RETURN_ERROR_IF(src==NULL, GENERIC, "invalid parameter"); if ( (format != ZSTD_f_zstd1_magicless) && (MEM_readLE32(src) != ZSTD_MAGICNUMBER) ) { if ((MEM_readLE32(src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */ if (srcSize < ZSTD_SKIPPABLEHEADERSIZE) return ZSTD_SKIPPABLEHEADERSIZE; /* magic number + frame length */ memset(zfhPtr, 0, sizeof(*zfhPtr)); zfhPtr->frameContentSize = MEM_readLE32((const char *)src + ZSTD_FRAMEIDSIZE); zfhPtr->frameType = ZSTD_skippableFrame; return 0; } RETURN_ERROR(prefix_unknown); } /* ensure there is enough `srcSize` to fully read/decode frame header */ { size_t const fhsize = ZSTD_frameHeaderSize_internal(src, srcSize, format); if (srcSize < fhsize) return fhsize; zfhPtr->headerSize = (U32)fhsize; } { BYTE const fhdByte = ip[minInputSize-1]; size_t pos = minInputSize; U32 const dictIDSizeCode = fhdByte&3; U32 const checksumFlag = (fhdByte>>2)&1; U32 const singleSegment = (fhdByte>>5)&1; U32 const fcsID = fhdByte>>6; U64 windowSize = 0; U32 dictID = 0; U64 frameContentSize = ZSTD_CONTENTSIZE_UNKNOWN; RETURN_ERROR_IF((fhdByte & 0x08) != 0, frameParameter_unsupported, "reserved bits, must be zero"); if (!singleSegment) { BYTE const wlByte = ip[pos++]; U32 const windowLog = (wlByte >> 3) + ZSTD_WINDOWLOG_ABSOLUTEMIN; RETURN_ERROR_IF(windowLog > ZSTD_WINDOWLOG_MAX, frameParameter_windowTooLarge); windowSize = (1ULL << windowLog); windowSize += (windowSize >> 3) * (wlByte&7); } switch(dictIDSizeCode) { default: assert(0); /* 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: assert(0); /* 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 (singleSegment) windowSize = frameContentSize; zfhPtr->frameType = ZSTD_frame; zfhPtr->frameContentSize = frameContentSize; zfhPtr->windowSize = windowSize; zfhPtr->blockSizeMax = (unsigned) MIN(windowSize, ZSTD_BLOCKSIZE_MAX); zfhPtr->dictID = dictID; zfhPtr->checksumFlag = checksumFlag; } return 0; } /** ZSTD_getFrameHeader() : * decode Frame Header, or require larger `srcSize`. * note : this function does not consume input, it only reads it. * @return : 0, `zfhPtr` is correctly filled, * >0, `srcSize` is too small, value is wanted `srcSize` amount, * or an error code, which can be tested using ZSTD_isError() */ size_t ZSTD_getFrameHeader(ZSTD_frameHeader* zfhPtr, const void* src, size_t srcSize) { return ZSTD_getFrameHeader_advanced(zfhPtr, src, srcSize, ZSTD_f_zstd1); } /** 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 zfh; if (ZSTD_getFrameHeader(&zfh, src, srcSize) != 0) return ZSTD_CONTENTSIZE_ERROR; if (zfh.frameType == ZSTD_skippableFrame) { return 0; } else { return zfh.frameContentSize; } } } static size_t readSkippableFrameSize(void const* src, size_t srcSize) { size_t const skippableHeaderSize = ZSTD_SKIPPABLEHEADERSIZE; U32 sizeU32; RETURN_ERROR_IF(srcSize < ZSTD_SKIPPABLEHEADERSIZE, srcSize_wrong); sizeU32 = MEM_readLE32((BYTE const*)src + ZSTD_FRAMEIDSIZE); RETURN_ERROR_IF((U32)(sizeU32 + ZSTD_SKIPPABLEHEADERSIZE) < sizeU32, frameParameter_unsupported); { size_t const skippableSize = skippableHeaderSize + sizeU32; RETURN_ERROR_IF(skippableSize > srcSize, srcSize_wrong); return skippableSize; } } /** 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_startingInputLength(ZSTD_f_zstd1)) { U32 const magicNumber = MEM_readLE32(src); if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { size_t const skippableSize = readSkippableFrameSize(src, srcSize); if (ZSTD_isError(skippableSize)) { return ZSTD_CONTENTSIZE_ERROR; } assert(skippableSize <= srcSize); 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; } } /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */ 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 : - frame content is empty - decompressed size field is not present in 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); ZSTD_STATIC_ASSERT(ZSTD_CONTENTSIZE_ERROR < ZSTD_CONTENTSIZE_UNKNOWN); 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_advanced(&(dctx->fParams), src, headerSize, dctx->format); if (ZSTD_isError(result)) return result; /* invalid header */ RETURN_ERROR_IF(result>0, srcSize_wrong, "headerSize too small"); #ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION /* Skip the dictID check in fuzzing mode, because it makes the search * harder. */ RETURN_ERROR_IF(dctx->fParams.dictID && (dctx->dictID != dctx->fParams.dictID), dictionary_wrong); #endif if (dctx->fParams.checksumFlag) XXH64_reset(&dctx->xxhState, 0); return 0; } static ZSTD_frameSizeInfo ZSTD_errorFrameSizeInfo(size_t ret) { ZSTD_frameSizeInfo frameSizeInfo; frameSizeInfo.compressedSize = ret; frameSizeInfo.decompressedBound = ZSTD_CONTENTSIZE_ERROR; return frameSizeInfo; } static ZSTD_frameSizeInfo ZSTD_findFrameSizeInfo(const void* src, size_t srcSize) { ZSTD_frameSizeInfo frameSizeInfo; memset(&frameSizeInfo, 0, sizeof(ZSTD_frameSizeInfo)); #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT >= 1) if (ZSTD_isLegacy(src, srcSize)) return ZSTD_findFrameSizeInfoLegacy(src, srcSize); #endif if ((srcSize >= ZSTD_SKIPPABLEHEADERSIZE) && (MEM_readLE32(src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { frameSizeInfo.compressedSize = readSkippableFrameSize(src, srcSize); assert(ZSTD_isError(frameSizeInfo.compressedSize) || frameSizeInfo.compressedSize <= srcSize); return frameSizeInfo; } else { const BYTE* ip = (const BYTE*)src; const BYTE* const ipstart = ip; size_t remainingSize = srcSize; size_t nbBlocks = 0; ZSTD_frameHeader zfh; /* Extract Frame Header */ { size_t const ret = ZSTD_getFrameHeader(&zfh, src, srcSize); if (ZSTD_isError(ret)) return ZSTD_errorFrameSizeInfo(ret); if (ret > 0) return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong)); } ip += zfh.headerSize; remainingSize -= zfh.headerSize; /* Iterate over each block */ while (1) { blockProperties_t blockProperties; size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSize, &blockProperties); if (ZSTD_isError(cBlockSize)) return ZSTD_errorFrameSizeInfo(cBlockSize); if (ZSTD_blockHeaderSize + cBlockSize > remainingSize) return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong)); ip += ZSTD_blockHeaderSize + cBlockSize; remainingSize -= ZSTD_blockHeaderSize + cBlockSize; nbBlocks++; if (blockProperties.lastBlock) break; } /* Final frame content checksum */ if (zfh.checksumFlag) { if (remainingSize < 4) return ZSTD_errorFrameSizeInfo(ERROR(srcSize_wrong)); ip += 4; } frameSizeInfo.compressedSize = ip - ipstart; frameSizeInfo.decompressedBound = (zfh.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) ? zfh.frameContentSize : nbBlocks * zfh.blockSizeMax; return frameSizeInfo; } } /** 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) { ZSTD_frameSizeInfo const frameSizeInfo = ZSTD_findFrameSizeInfo(src, srcSize); return frameSizeInfo.compressedSize; } /** ZSTD_decompressBound() : * compatible with legacy mode * `src` must point to the start of a ZSTD frame or a skippeable frame * `srcSize` must be at least as large as the frame contained * @return : the maximum decompressed size of the compressed source */ unsigned long long ZSTD_decompressBound(const void* src, size_t srcSize) { unsigned long long bound = 0; /* Iterate over each frame */ while (srcSize > 0) { ZSTD_frameSizeInfo const frameSizeInfo = ZSTD_findFrameSizeInfo(src, srcSize); size_t const compressedSize = frameSizeInfo.compressedSize; unsigned long long const decompressedBound = frameSizeInfo.decompressedBound; if (ZSTD_isError(compressedSize) || decompressedBound == ZSTD_CONTENTSIZE_ERROR) return ZSTD_CONTENTSIZE_ERROR; assert(srcSize >= compressedSize); src = (const BYTE*)src + compressedSize; srcSize -= compressedSize; bound += decompressedBound; } return bound; } /*-************************************************************* * Frame decoding ***************************************************************/ void ZSTD_checkContinuity(ZSTD_DCtx* dctx, const void* dst) { if (dst != dctx->previousDstEnd) { /* not contiguous */ dctx->dictEnd = dctx->previousDstEnd; dctx->virtualStart = (const char*)dst - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->prefixStart)); dctx->prefixStart = dst; dctx->previousDstEnd = dst; } } /** ZSTD_insertBlock() : * insert `src` block into `dctx` history. Useful to track uncompressed blocks. */ size_t ZSTD_insertBlock(ZSTD_DCtx* dctx, const void* blockStart, size_t blockSize) { DEBUGLOG(5, "ZSTD_insertBlock: %u bytes", (unsigned)blockSize); ZSTD_checkContinuity(dctx, blockStart); dctx->previousDstEnd = (const char*)blockStart + blockSize; return blockSize; } static size_t ZSTD_copyRawBlock(void* dst, size_t dstCapacity, const void* src, size_t srcSize) { DEBUGLOG(5, "ZSTD_copyRawBlock"); if (dst == NULL) { if (srcSize == 0) return 0; RETURN_ERROR(dstBuffer_null); } RETURN_ERROR_IF(srcSize > dstCapacity, dstSize_tooSmall); memcpy(dst, src, srcSize); return srcSize; } static size_t ZSTD_setRleBlock(void* dst, size_t dstCapacity, BYTE b, size_t regenSize) { if (dst == NULL) { if (regenSize == 0) return 0; RETURN_ERROR(dstBuffer_null); } RETURN_ERROR_IF(regenSize > dstCapacity, dstSize_tooSmall); memset(dst, b, regenSize); return regenSize; } /*! ZSTD_decompressFrame() : * @dctx must be properly initialized * will update *srcPtr and *srcSizePtr, * to make *srcPtr progress by one frame. */ 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 remainingSrcSize = *srcSizePtr; DEBUGLOG(4, "ZSTD_decompressFrame (srcSize:%i)", (int)*srcSizePtr); /* check */ RETURN_ERROR_IF( remainingSrcSize < ZSTD_FRAMEHEADERSIZE_MIN(dctx->format)+ZSTD_blockHeaderSize, srcSize_wrong); /* Frame Header */ { size_t const frameHeaderSize = ZSTD_frameHeaderSize_internal( ip, ZSTD_FRAMEHEADERSIZE_PREFIX(dctx->format), dctx->format); if (ZSTD_isError(frameHeaderSize)) return frameHeaderSize; RETURN_ERROR_IF(remainingSrcSize < frameHeaderSize+ZSTD_blockHeaderSize, srcSize_wrong); FORWARD_IF_ERROR( ZSTD_decodeFrameHeader(dctx, ip, frameHeaderSize) ); ip += frameHeaderSize; remainingSrcSize -= frameHeaderSize; } /* Loop on each block */ while (1) { size_t decodedSize; blockProperties_t blockProperties; size_t const cBlockSize = ZSTD_getcBlockSize(ip, remainingSrcSize, &blockProperties); if (ZSTD_isError(cBlockSize)) return cBlockSize; ip += ZSTD_blockHeaderSize; remainingSrcSize -= ZSTD_blockHeaderSize; RETURN_ERROR_IF(cBlockSize > remainingSrcSize, srcSize_wrong); switch(blockProperties.blockType) { case bt_compressed: decodedSize = ZSTD_decompressBlock_internal(dctx, op, oend-op, ip, cBlockSize, /* frame */ 1); break; case bt_raw : decodedSize = ZSTD_copyRawBlock(op, oend-op, ip, cBlockSize); break; case bt_rle : decodedSize = ZSTD_setRleBlock(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; remainingSrcSize -= cBlockSize; if (blockProperties.lastBlock) break; } if (dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN) { RETURN_ERROR_IF((U64)(op-ostart) != dctx->fParams.frameContentSize, corruption_detected); } if (dctx->fParams.checksumFlag) { /* Frame content checksum verification */ U32 const checkCalc = (U32)XXH64_digest(&dctx->xxhState); U32 checkRead; RETURN_ERROR_IF(remainingSrcSize<4, checksum_wrong); checkRead = MEM_readLE32(ip); RETURN_ERROR_IF(checkRead != checkCalc, checksum_wrong); ip += 4; remainingSrcSize -= 4; } /* Allow caller to get size read */ *srcPtr = ip; *srcSizePtr = remainingSrcSize; return op-ostart; } 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; int moreThan1Frame = 0; DEBUGLOG(5, "ZSTD_decompressMultiFrame"); assert(dict==NULL || ddict==NULL); /* either dict or ddict set, not both */ if (ddict) { dict = ZSTD_DDict_dictContent(ddict); dictSize = ZSTD_DDict_dictSize(ddict); } while (srcSize >= ZSTD_startingInputLength(dctx->format)) { #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; RETURN_ERROR_IF(dctx->staticSize, memory_allocation, "legacy support is not compatible with static dctx"); decodedSize = ZSTD_decompressLegacy(dst, dstCapacity, src, frameSize, dict, dictSize); if (ZSTD_isError(decodedSize)) return decodedSize; assert(decodedSize <=- dstCapacity); dst = (BYTE*)dst + decodedSize; dstCapacity -= decodedSize; src = (const BYTE*)src + frameSize; srcSize -= frameSize; continue; } #endif { U32 const magicNumber = MEM_readLE32(src); DEBUGLOG(4, "reading magic number %08X (expecting %08X)", (unsigned)magicNumber, ZSTD_MAGICNUMBER); if ((magicNumber & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { size_t const skippableSize = readSkippableFrameSize(src, srcSize); FORWARD_IF_ERROR(skippableSize); assert(skippableSize <= srcSize); src = (const BYTE *)src + skippableSize; srcSize -= skippableSize; continue; } } if (ddict) { /* we were called from ZSTD_decompress_usingDDict */ FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(dctx, ddict)); } else { /* this will initialize correctly with no dict if dict == NULL, so * use this in all cases but ddict */ FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDict(dctx, dict, dictSize)); } ZSTD_checkContinuity(dctx, dst); { const size_t res = ZSTD_decompressFrame(dctx, dst, dstCapacity, &src, &srcSize); RETURN_ERROR_IF( (ZSTD_getErrorCode(res) == ZSTD_error_prefix_unknown) && (moreThan1Frame==1), srcSize_wrong, "at least one frame successfully completed, but following " "bytes are garbage: it's more likely to be a srcSize error, " "specifying more bytes than compressed size of frame(s). This " "error message replaces ERROR(prefix_unknown), which would be " "confusing, as the first header is actually correct. Note that " "one could be unlucky, it might be a corruption error instead, " "happening right at the place where we expect zstd magic " "bytes. But this is _much_ less likely than a srcSize field " "error."); if (ZSTD_isError(res)) return res; assert(res <= dstCapacity); dst = (BYTE*)dst + res; dstCapacity -= res; } moreThan1Frame = 1; } /* while (srcSize >= ZSTD_frameHeaderSize_prefix) */ RETURN_ERROR_IF(srcSize, 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); } static ZSTD_DDict const* ZSTD_getDDict(ZSTD_DCtx* dctx) { switch (dctx->dictUses) { default: assert(0 /* Impossible */); /* fall-through */ case ZSTD_dont_use: ZSTD_clearDict(dctx); return NULL; case ZSTD_use_indefinitely: return dctx->ddict; case ZSTD_use_once: dctx->dictUses = ZSTD_dont_use; return dctx->ddict; } } size_t ZSTD_decompressDCtx(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize) { return ZSTD_decompress_usingDDict(dctx, dst, dstCapacity, src, srcSize, ZSTD_getDDict(dctx)); } 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(); RETURN_ERROR_IF(dctx==NULL, memory_allocation); regenSize = ZSTD_decompressDCtx(dctx, dst, dstCapacity, src, srcSize); ZSTD_freeDCtx(dctx); return regenSize; #else /* stack mode */ ZSTD_DCtx dctx; ZSTD_initDCtx_internal(&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 */ assert(0); 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; } } static int ZSTD_isSkipFrame(ZSTD_DCtx* dctx) { return dctx->stage == ZSTDds_skipFrame; } /** ZSTD_decompressContinue() : * srcSize : must be the exact nb of bytes expected (see ZSTD_nextSrcSizeToDecompress()) * @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) { DEBUGLOG(5, "ZSTD_decompressContinue (srcSize:%u)", (unsigned)srcSize); /* Sanity check */ RETURN_ERROR_IF(srcSize != dctx->expected, srcSize_wrong, "not allowed"); if (dstCapacity) ZSTD_checkContinuity(dctx, dst); switch (dctx->stage) { case ZSTDds_getFrameHeaderSize : assert(src != NULL); if (dctx->format == ZSTD_f_zstd1) { /* allows header */ assert(srcSize >= ZSTD_FRAMEIDSIZE); /* to read skippable magic number */ if ((MEM_readLE32(src) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */ memcpy(dctx->headerBuffer, src, srcSize); dctx->expected = ZSTD_SKIPPABLEHEADERSIZE - srcSize; /* remaining to load to get full skippable frame header */ dctx->stage = ZSTDds_decodeSkippableHeader; return 0; } } dctx->headerSize = ZSTD_frameHeaderSize_internal(src, srcSize, dctx->format); if (ZSTD_isError(dctx->headerSize)) return dctx->headerSize; memcpy(dctx->headerBuffer, src, srcSize); dctx->expected = dctx->headerSize - srcSize; dctx->stage = ZSTDds_decodeFrameHeader; return 0; case ZSTDds_decodeFrameHeader: assert(src != NULL); memcpy(dctx->headerBuffer + (dctx->headerSize - srcSize), src, srcSize); FORWARD_IF_ERROR(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; RETURN_ERROR_IF(cBlockSize > dctx->fParams.blockSizeMax, corruption_detected, "Block Size Exceeds Maximum"); 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 = ZSTD_blockHeaderSize; /* jump to next header */ dctx->stage = ZSTDds_decodeBlockHeader; } return 0; } case ZSTDds_decompressLastBlock: case ZSTDds_decompressBlock: DEBUGLOG(5, "ZSTD_decompressContinue: case ZSTDds_decompressBlock"); { size_t rSize; switch(dctx->bType) { case bt_compressed: DEBUGLOG(5, "ZSTD_decompressContinue: case bt_compressed"); rSize = ZSTD_decompressBlock_internal(dctx, dst, dstCapacity, src, srcSize, /* frame */ 1); break; case bt_raw : rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize); break; case bt_rle : rSize = ZSTD_setRleBlock(dst, dstCapacity, *(const BYTE*)src, dctx->rleSize); break; case bt_reserved : /* should never happen */ default: RETURN_ERROR(corruption_detected); } if (ZSTD_isError(rSize)) return rSize; RETURN_ERROR_IF(rSize > dctx->fParams.blockSizeMax, corruption_detected, "Decompressed Block Size Exceeds Maximum"); DEBUGLOG(5, "ZSTD_decompressContinue: decoded size from block : %u", (unsigned)rSize); dctx->decodedSize += rSize; if (dctx->fParams.checksumFlag) XXH64_update(&dctx->xxhState, dst, rSize); if (dctx->stage == ZSTDds_decompressLastBlock) { /* end of frame */ DEBUGLOG(4, "ZSTD_decompressContinue: decoded size from frame : %u", (unsigned)dctx->decodedSize); RETURN_ERROR_IF( dctx->fParams.frameContentSize != ZSTD_CONTENTSIZE_UNKNOWN && dctx->decodedSize != dctx->fParams.frameContentSize, corruption_detected); 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: assert(srcSize == 4); /* guaranteed by dctx->expected */ { U32 const h32 = (U32)XXH64_digest(&dctx->xxhState); U32 const check32 = MEM_readLE32(src); DEBUGLOG(4, "ZSTD_decompressContinue: checksum : calculated %08X :: %08X read", (unsigned)h32, (unsigned)check32); RETURN_ERROR_IF(check32 != h32, checksum_wrong); dctx->expected = 0; dctx->stage = ZSTDds_getFrameHeaderSize; return 0; } case ZSTDds_decodeSkippableHeader: assert(src != NULL); assert(srcSize <= ZSTD_SKIPPABLEHEADERSIZE); memcpy(dctx->headerBuffer + (ZSTD_SKIPPABLEHEADERSIZE - srcSize), src, srcSize); /* complete skippable header */ dctx->expected = MEM_readLE32(dctx->headerBuffer + ZSTD_FRAMEIDSIZE); /* note : dctx->expected can grow seriously large, beyond local buffer size */ dctx->stage = ZSTDds_skipFrame; return 0; case ZSTDds_skipFrame: dctx->expected = 0; dctx->stage = ZSTDds_getFrameHeaderSize; return 0; default: assert(0); /* impossible */ RETURN_ERROR(GENERIC); /* some compiler require default to do something */ } } static size_t ZSTD_refDictContent(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) { dctx->dictEnd = dctx->previousDstEnd; dctx->virtualStart = (const char*)dict - ((const char*)(dctx->previousDstEnd) - (const char*)(dctx->prefixStart)); dctx->prefixStart = dict; dctx->previousDstEnd = (const char*)dict + dictSize; return 0; } /*! ZSTD_loadDEntropy() : * dict : must point at beginning of a valid zstd dictionary. * @return : size of entropy tables read */ size_t ZSTD_loadDEntropy(ZSTD_entropyDTables_t* entropy, const void* const dict, size_t const dictSize) { const BYTE* dictPtr = (const BYTE*)dict; const BYTE* const dictEnd = dictPtr + dictSize; RETURN_ERROR_IF(dictSize <= 8, dictionary_corrupted); assert(MEM_readLE32(dict) == ZSTD_MAGIC_DICTIONARY); /* dict must be valid */ dictPtr += 8; /* skip header = magic + dictID */ ZSTD_STATIC_ASSERT(offsetof(ZSTD_entropyDTables_t, OFTable) == offsetof(ZSTD_entropyDTables_t, LLTable) + sizeof(entropy->LLTable)); ZSTD_STATIC_ASSERT(offsetof(ZSTD_entropyDTables_t, MLTable) == offsetof(ZSTD_entropyDTables_t, OFTable) + sizeof(entropy->OFTable)); ZSTD_STATIC_ASSERT(sizeof(entropy->LLTable) + sizeof(entropy->OFTable) + sizeof(entropy->MLTable) >= HUF_DECOMPRESS_WORKSPACE_SIZE); { void* const workspace = &entropy->LLTable; /* use fse tables as temporary workspace; implies fse tables are grouped together */ size_t const workspaceSize = sizeof(entropy->LLTable) + sizeof(entropy->OFTable) + sizeof(entropy->MLTable); #ifdef HUF_FORCE_DECOMPRESS_X1 /* in minimal huffman, we always use X1 variants */ size_t const hSize = HUF_readDTableX1_wksp(entropy->hufTable, dictPtr, dictEnd - dictPtr, workspace, workspaceSize); #else size_t const hSize = HUF_readDTableX2_wksp(entropy->hufTable, dictPtr, dictEnd - dictPtr, workspace, workspaceSize); #endif RETURN_ERROR_IF(HUF_isError(hSize), dictionary_corrupted); dictPtr += hSize; } { short offcodeNCount[MaxOff+1]; unsigned offcodeMaxValue = MaxOff, offcodeLog; size_t const offcodeHeaderSize = FSE_readNCount(offcodeNCount, &offcodeMaxValue, &offcodeLog, dictPtr, dictEnd-dictPtr); RETURN_ERROR_IF(FSE_isError(offcodeHeaderSize), dictionary_corrupted); RETURN_ERROR_IF(offcodeMaxValue > MaxOff, dictionary_corrupted); RETURN_ERROR_IF(offcodeLog > OffFSELog, dictionary_corrupted); ZSTD_buildFSETable( entropy->OFTable, offcodeNCount, offcodeMaxValue, OF_base, OF_bits, offcodeLog); dictPtr += offcodeHeaderSize; } { short matchlengthNCount[MaxML+1]; unsigned matchlengthMaxValue = MaxML, matchlengthLog; size_t const matchlengthHeaderSize = FSE_readNCount(matchlengthNCount, &matchlengthMaxValue, &matchlengthLog, dictPtr, dictEnd-dictPtr); RETURN_ERROR_IF(FSE_isError(matchlengthHeaderSize), dictionary_corrupted); RETURN_ERROR_IF(matchlengthMaxValue > MaxML, dictionary_corrupted); RETURN_ERROR_IF(matchlengthLog > MLFSELog, dictionary_corrupted); ZSTD_buildFSETable( entropy->MLTable, matchlengthNCount, matchlengthMaxValue, ML_base, ML_bits, matchlengthLog); dictPtr += matchlengthHeaderSize; } { short litlengthNCount[MaxLL+1]; unsigned litlengthMaxValue = MaxLL, litlengthLog; size_t const litlengthHeaderSize = FSE_readNCount(litlengthNCount, &litlengthMaxValue, &litlengthLog, dictPtr, dictEnd-dictPtr); RETURN_ERROR_IF(FSE_isError(litlengthHeaderSize), dictionary_corrupted); RETURN_ERROR_IF(litlengthMaxValue > MaxLL, dictionary_corrupted); RETURN_ERROR_IF(litlengthLog > LLFSELog, dictionary_corrupted); ZSTD_buildFSETable( entropy->LLTable, litlengthNCount, litlengthMaxValue, LL_base, LL_bits, litlengthLog); dictPtr += litlengthHeaderSize; } RETURN_ERROR_IF(dictPtr+12 > dictEnd, 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; RETURN_ERROR_IF(rep==0 || rep > dictContentSize, 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_MAGIC_DICTIONARY) { return ZSTD_refDictContent(dctx, dict, dictSize); /* pure content mode */ } } dctx->dictID = MEM_readLE32((const char*)dict + ZSTD_FRAMEIDSIZE); /* load entropy tables */ { size_t const eSize = ZSTD_loadDEntropy(&dctx->entropy, dict, dictSize); RETURN_ERROR_IF(ZSTD_isError(eSize), 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(ZSTD_DCtx* dctx) { assert(dctx != NULL); dctx->expected = ZSTD_startingInputLength(dctx->format); /* dctx->format must be properly set */ dctx->stage = ZSTDds_getFrameHeaderSize; dctx->decodedSize = 0; dctx->previousDstEnd = NULL; dctx->prefixStart = NULL; dctx->virtualStart = NULL; dctx->dictEnd = NULL; dctx->entropy.hufTable[0] = (HUF_DTable)((HufLog)*0x1000001); /* cover both little and big endian */ dctx->litEntropy = dctx->fseEntropy = 0; dctx->dictID = 0; ZSTD_STATIC_ASSERT(sizeof(dctx->entropy.rep) == sizeof(repStartValue)); memcpy(dctx->entropy.rep, repStartValue, sizeof(repStartValue)); /* initial repcodes */ dctx->LLTptr = dctx->entropy.LLTable; dctx->MLTptr = dctx->entropy.MLTable; dctx->OFTptr = dctx->entropy.OFTable; dctx->HUFptr = dctx->entropy.hufTable; return 0; } size_t ZSTD_decompressBegin_usingDict(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) { FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) ); if (dict && dictSize) RETURN_ERROR_IF( ZSTD_isError(ZSTD_decompress_insertDictionary(dctx, dict, dictSize)), dictionary_corrupted); return 0; } /* ====== ZSTD_DDict ====== */ size_t ZSTD_decompressBegin_usingDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict) { DEBUGLOG(4, "ZSTD_decompressBegin_usingDDict"); assert(dctx != NULL); if (ddict) { const char* const dictStart = (const char*)ZSTD_DDict_dictContent(ddict); size_t const dictSize = ZSTD_DDict_dictSize(ddict); const void* const dictEnd = dictStart + dictSize; dctx->ddictIsCold = (dctx->dictEnd != dictEnd); DEBUGLOG(4, "DDict is %s", dctx->ddictIsCold ? "~cold~" : "hot!"); } FORWARD_IF_ERROR( ZSTD_decompressBegin(dctx) ); if (ddict) { /* NULL ddict is equivalent to no dictionary */ ZSTD_copyDDictParameters(dctx, ddict); } return 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_MAGIC_DICTIONARY) return 0; return MEM_readLE32((const char*)dict + ZSTD_FRAMEIDSIZE); } /*! ZSTD_getDictID_fromFrame() : * Provides the dictID required to decompress 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, ZSTD_frame, 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 *====================================*/ ZSTD_DStream* ZSTD_createDStream(void) { DEBUGLOG(3, "ZSTD_createDStream"); return ZSTD_createDStream_advanced(ZSTD_defaultCMem); } ZSTD_DStream* ZSTD_initStaticDStream(void *workspace, size_t workspaceSize) { return ZSTD_initStaticDCtx(workspace, workspaceSize); } ZSTD_DStream* ZSTD_createDStream_advanced(ZSTD_customMem customMem) { return ZSTD_createDCtx_advanced(customMem); } size_t ZSTD_freeDStream(ZSTD_DStream* zds) { return ZSTD_freeDCtx(zds); } /* *** Initialization *** */ size_t ZSTD_DStreamInSize(void) { return ZSTD_BLOCKSIZE_MAX + ZSTD_blockHeaderSize; } size_t ZSTD_DStreamOutSize(void) { return ZSTD_BLOCKSIZE_MAX; } size_t ZSTD_DCtx_loadDictionary_advanced(ZSTD_DCtx* dctx, const void* dict, size_t dictSize, ZSTD_dictLoadMethod_e dictLoadMethod, ZSTD_dictContentType_e dictContentType) { RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong); ZSTD_clearDict(dctx); if (dict && dictSize != 0) { dctx->ddictLocal = ZSTD_createDDict_advanced(dict, dictSize, dictLoadMethod, dictContentType, dctx->customMem); RETURN_ERROR_IF(dctx->ddictLocal == NULL, memory_allocation); dctx->ddict = dctx->ddictLocal; dctx->dictUses = ZSTD_use_indefinitely; } return 0; } size_t ZSTD_DCtx_loadDictionary_byReference(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) { return ZSTD_DCtx_loadDictionary_advanced(dctx, dict, dictSize, ZSTD_dlm_byRef, ZSTD_dct_auto); } size_t ZSTD_DCtx_loadDictionary(ZSTD_DCtx* dctx, const void* dict, size_t dictSize) { return ZSTD_DCtx_loadDictionary_advanced(dctx, dict, dictSize, ZSTD_dlm_byCopy, ZSTD_dct_auto); } size_t ZSTD_DCtx_refPrefix_advanced(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize, ZSTD_dictContentType_e dictContentType) { FORWARD_IF_ERROR(ZSTD_DCtx_loadDictionary_advanced(dctx, prefix, prefixSize, ZSTD_dlm_byRef, dictContentType)); dctx->dictUses = ZSTD_use_once; return 0; } size_t ZSTD_DCtx_refPrefix(ZSTD_DCtx* dctx, const void* prefix, size_t prefixSize) { return ZSTD_DCtx_refPrefix_advanced(dctx, prefix, prefixSize, ZSTD_dct_rawContent); } /* ZSTD_initDStream_usingDict() : * return : expected size, aka ZSTD_startingInputLength(). * this function cannot fail */ size_t ZSTD_initDStream_usingDict(ZSTD_DStream* zds, const void* dict, size_t dictSize) { DEBUGLOG(4, "ZSTD_initDStream_usingDict"); FORWARD_IF_ERROR( ZSTD_DCtx_reset(zds, ZSTD_reset_session_only) ); FORWARD_IF_ERROR( ZSTD_DCtx_loadDictionary(zds, dict, dictSize) ); return ZSTD_startingInputLength(zds->format); } /* note : this variant can't fail */ size_t ZSTD_initDStream(ZSTD_DStream* zds) { DEBUGLOG(4, "ZSTD_initDStream"); return ZSTD_initDStream_usingDDict(zds, NULL); } /* ZSTD_initDStream_usingDDict() : * ddict will just be referenced, and must outlive decompression session * this function cannot fail */ size_t ZSTD_initDStream_usingDDict(ZSTD_DStream* dctx, const ZSTD_DDict* ddict) { FORWARD_IF_ERROR( ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only) ); FORWARD_IF_ERROR( ZSTD_DCtx_refDDict(dctx, ddict) ); return ZSTD_startingInputLength(dctx->format); } /* ZSTD_resetDStream() : * return : expected size, aka ZSTD_startingInputLength(). * this function cannot fail */ size_t ZSTD_resetDStream(ZSTD_DStream* dctx) { FORWARD_IF_ERROR(ZSTD_DCtx_reset(dctx, ZSTD_reset_session_only)); return ZSTD_startingInputLength(dctx->format); } size_t ZSTD_DCtx_refDDict(ZSTD_DCtx* dctx, const ZSTD_DDict* ddict) { RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong); ZSTD_clearDict(dctx); if (ddict) { dctx->ddict = ddict; dctx->dictUses = ZSTD_use_indefinitely; } return 0; } /* ZSTD_DCtx_setMaxWindowSize() : * note : no direct equivalence in ZSTD_DCtx_setParameter, * since this version sets windowSize, and the other sets windowLog */ size_t ZSTD_DCtx_setMaxWindowSize(ZSTD_DCtx* dctx, size_t maxWindowSize) { ZSTD_bounds const bounds = ZSTD_dParam_getBounds(ZSTD_d_windowLogMax); size_t const min = (size_t)1 << bounds.lowerBound; size_t const max = (size_t)1 << bounds.upperBound; RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong); RETURN_ERROR_IF(maxWindowSize < min, parameter_outOfBound); RETURN_ERROR_IF(maxWindowSize > max, parameter_outOfBound); dctx->maxWindowSize = maxWindowSize; return 0; } size_t ZSTD_DCtx_setFormat(ZSTD_DCtx* dctx, ZSTD_format_e format) { return ZSTD_DCtx_setParameter(dctx, ZSTD_d_format, format); } ZSTD_bounds ZSTD_dParam_getBounds(ZSTD_dParameter dParam) { ZSTD_bounds bounds = { 0, 0, 0 }; switch(dParam) { case ZSTD_d_windowLogMax: bounds.lowerBound = ZSTD_WINDOWLOG_ABSOLUTEMIN; bounds.upperBound = ZSTD_WINDOWLOG_MAX; return bounds; case ZSTD_d_format: bounds.lowerBound = (int)ZSTD_f_zstd1; bounds.upperBound = (int)ZSTD_f_zstd1_magicless; ZSTD_STATIC_ASSERT(ZSTD_f_zstd1 < ZSTD_f_zstd1_magicless); return bounds; default:; } bounds.error = ERROR(parameter_unsupported); return bounds; } /* ZSTD_dParam_withinBounds: * @return 1 if value is within dParam bounds, * 0 otherwise */ static int ZSTD_dParam_withinBounds(ZSTD_dParameter dParam, int value) { ZSTD_bounds const bounds = ZSTD_dParam_getBounds(dParam); if (ZSTD_isError(bounds.error)) return 0; if (value < bounds.lowerBound) return 0; if (value > bounds.upperBound) return 0; return 1; } #define CHECK_DBOUNDS(p,v) { \ RETURN_ERROR_IF(!ZSTD_dParam_withinBounds(p, v), parameter_outOfBound); \ } size_t ZSTD_DCtx_setParameter(ZSTD_DCtx* dctx, ZSTD_dParameter dParam, int value) { RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong); switch(dParam) { case ZSTD_d_windowLogMax: if (value == 0) value = ZSTD_WINDOWLOG_LIMIT_DEFAULT; CHECK_DBOUNDS(ZSTD_d_windowLogMax, value); dctx->maxWindowSize = ((size_t)1) << value; return 0; case ZSTD_d_format: CHECK_DBOUNDS(ZSTD_d_format, value); dctx->format = (ZSTD_format_e)value; return 0; default:; } RETURN_ERROR(parameter_unsupported); } size_t ZSTD_DCtx_reset(ZSTD_DCtx* dctx, ZSTD_ResetDirective reset) { if ( (reset == ZSTD_reset_session_only) || (reset == ZSTD_reset_session_and_parameters) ) { dctx->streamStage = zdss_init; dctx->noForwardProgress = 0; } if ( (reset == ZSTD_reset_parameters) || (reset == ZSTD_reset_session_and_parameters) ) { RETURN_ERROR_IF(dctx->streamStage != zdss_init, stage_wrong); ZSTD_clearDict(dctx); dctx->format = ZSTD_f_zstd1; dctx->maxWindowSize = ZSTD_MAXWINDOWSIZE_DEFAULT; } return 0; } size_t ZSTD_sizeof_DStream(const ZSTD_DStream* dctx) { return ZSTD_sizeof_DCtx(dctx); } size_t ZSTD_decodingBufferSize_min(unsigned long long windowSize, unsigned long long frameContentSize) { size_t const blockSize = (size_t) MIN(windowSize, ZSTD_BLOCKSIZE_MAX); unsigned long long const neededRBSize = windowSize + blockSize + (WILDCOPY_OVERLENGTH * 2); unsigned long long const neededSize = MIN(frameContentSize, neededRBSize); size_t const minRBSize = (size_t) neededSize; RETURN_ERROR_IF((unsigned long long)minRBSize != neededSize, frameParameter_windowTooLarge); return minRBSize; } size_t ZSTD_estimateDStreamSize(size_t windowSize) { size_t const blockSize = MIN(windowSize, ZSTD_BLOCKSIZE_MAX); size_t const inBuffSize = blockSize; /* no block can be larger */ size_t const outBuffSize = ZSTD_decodingBufferSize_min(windowSize, ZSTD_CONTENTSIZE_UNKNOWN); return ZSTD_estimateDCtxSize() + inBuffSize + outBuffSize; } size_t ZSTD_estimateDStreamSize_fromFrame(const void* src, size_t srcSize) { U32 const windowSizeMax = 1U << ZSTD_WINDOWLOG_MAX; /* note : should be user-selectable, but requires an additional parameter (or a dctx) */ ZSTD_frameHeader zfh; size_t const err = ZSTD_getFrameHeader(&zfh, src, srcSize); if (ZSTD_isError(err)) return err; RETURN_ERROR_IF(err>0, srcSize_wrong); RETURN_ERROR_IF(zfh.windowSize > windowSizeMax, frameParameter_windowTooLarge); return ZSTD_estimateDStreamSize((size_t)zfh.windowSize); } /* ***** 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; DEBUGLOG(5, "ZSTD_decompressStream"); RETURN_ERROR_IF( input->pos > input->size, srcSize_wrong, "forbidden. in: pos: %u vs size: %u", (U32)input->pos, (U32)input->size); RETURN_ERROR_IF( output->pos > output->size, dstSize_tooSmall, "forbidden. out: pos: %u vs size: %u", (U32)output->pos, (U32)output->size); DEBUGLOG(5, "input size : %u", (U32)(input->size - input->pos)); while (someMoreWork) { switch(zds->streamStage) { case zdss_init : DEBUGLOG(5, "stage zdss_init => transparent reset "); zds->streamStage = zdss_loadHeader; zds->lhSize = zds->inPos = zds->outStart = zds->outEnd = 0; zds->legacyVersion = 0; zds->hostageByte = 0; /* fall-through */ case zdss_loadHeader : DEBUGLOG(5, "stage zdss_loadHeader (srcSize : %u)", (U32)(iend - ip)); #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) if (zds->legacyVersion) { RETURN_ERROR_IF(zds->staticSize, memory_allocation, "legacy support is incompatible with static dctx"); { size_t const hint = ZSTD_decompressLegacyStream(zds->legacyContext, zds->legacyVersion, output, input); if (hint==0) zds->streamStage = zdss_init; return hint; } } #endif { size_t const hSize = ZSTD_getFrameHeader_advanced(&zds->fParams, zds->headerBuffer, zds->lhSize, zds->format); DEBUGLOG(5, "header size : %u", (U32)hSize); if (ZSTD_isError(hSize)) { #if defined(ZSTD_LEGACY_SUPPORT) && (ZSTD_LEGACY_SUPPORT>=1) U32 const legacyVersion = ZSTD_isLegacy(istart, iend-istart); if (legacyVersion) { ZSTD_DDict const* const ddict = ZSTD_getDDict(zds); const void* const dict = ddict ? ZSTD_DDict_dictContent(ddict) : NULL; size_t const dictSize = ddict ? ZSTD_DDict_dictSize(ddict) : 0; DEBUGLOG(5, "ZSTD_decompressStream: detected legacy version v0.%u", legacyVersion); RETURN_ERROR_IF(zds->staticSize, memory_allocation, "legacy support is incompatible with static dctx"); FORWARD_IF_ERROR(ZSTD_initLegacyStream(&zds->legacyContext, zds->previousLegacyVersion, legacyVersion, dict, dictSize)); zds->legacyVersion = zds->previousLegacyVersion = legacyVersion; { size_t const hint = ZSTD_decompressLegacyStream(zds->legacyContext, legacyVersion, output, input); if (hint==0) zds->streamStage = zdss_init; /* or stay in stage zdss_loadHeader */ return hint; } } #endif return hSize; /* error */ } if (hSize != 0) { /* need more input */ size_t const toLoad = hSize - zds->lhSize; /* if hSize!=0, hSize > zds->lhSize */ size_t const remainingInput = (size_t)(iend-ip); assert(iend >= ip); if (toLoad > remainingInput) { /* not enough input to load full header */ if (remainingInput > 0) { memcpy(zds->headerBuffer + zds->lhSize, ip, remainingInput); zds->lhSize += remainingInput; } input->pos = input->size; return (MAX((size_t)ZSTD_FRAMEHEADERSIZE_MIN(zds->format), hSize) - zds->lhSize) + ZSTD_blockHeaderSize; /* remaining header bytes + next block header */ } assert(ip != NULL); 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)) { /* shortcut : using single-pass mode */ size_t const decompressedSize = ZSTD_decompress_usingDDict(zds, op, oend-op, istart, cSize, ZSTD_getDDict(zds)); if (ZSTD_isError(decompressedSize)) return decompressedSize; DEBUGLOG(4, "shortcut to single-pass ZSTD_decompress_usingDDict()") ip = istart + cSize; op += decompressedSize; zds->expected = 0; zds->streamStage = zdss_init; someMoreWork = 0; break; } } /* Consume header (see ZSTDds_decodeFrameHeader) */ DEBUGLOG(4, "Consume header"); FORWARD_IF_ERROR(ZSTD_decompressBegin_usingDDict(zds, ZSTD_getDDict(zds))); if ((MEM_readLE32(zds->headerBuffer) & ZSTD_MAGIC_SKIPPABLE_MASK) == ZSTD_MAGIC_SKIPPABLE_START) { /* skippable frame */ zds->expected = MEM_readLE32(zds->headerBuffer + ZSTD_FRAMEIDSIZE); zds->stage = ZSTDds_skipFrame; } else { FORWARD_IF_ERROR(ZSTD_decodeFrameHeader(zds, zds->headerBuffer, zds->lhSize)); zds->expected = ZSTD_blockHeaderSize; zds->stage = ZSTDds_decodeBlockHeader; } /* control buffer memory usage */ DEBUGLOG(4, "Control max memory usage (%u KB <= max %u KB)", (U32)(zds->fParams.windowSize >>10), (U32)(zds->maxWindowSize >> 10) ); zds->fParams.windowSize = MAX(zds->fParams.windowSize, 1U << ZSTD_WINDOWLOG_ABSOLUTEMIN); RETURN_ERROR_IF(zds->fParams.windowSize > zds->maxWindowSize, frameParameter_windowTooLarge); /* Adapt buffer sizes to frame header instructions */ { size_t const neededInBuffSize = MAX(zds->fParams.blockSizeMax, 4 /* frame checksum */); size_t const neededOutBuffSize = ZSTD_decodingBufferSize_min(zds->fParams.windowSize, zds->fParams.frameContentSize); if ((zds->inBuffSize < neededInBuffSize) || (zds->outBuffSize < neededOutBuffSize)) { size_t const bufferSize = neededInBuffSize + neededOutBuffSize; DEBUGLOG(4, "inBuff : from %u to %u", (U32)zds->inBuffSize, (U32)neededInBuffSize); DEBUGLOG(4, "outBuff : from %u to %u", (U32)zds->outBuffSize, (U32)neededOutBuffSize); if (zds->staticSize) { /* static DCtx */ DEBUGLOG(4, "staticSize : %u", (U32)zds->staticSize); assert(zds->staticSize >= sizeof(ZSTD_DCtx)); /* controlled at init */ RETURN_ERROR_IF( bufferSize > zds->staticSize - sizeof(ZSTD_DCtx), memory_allocation); } else { ZSTD_free(zds->inBuff, zds->customMem); zds->inBuffSize = 0; zds->outBuffSize = 0; zds->inBuff = (char*)ZSTD_malloc(bufferSize, zds->customMem); RETURN_ERROR_IF(zds->inBuff == NULL, memory_allocation); } zds->inBuffSize = neededInBuffSize; zds->outBuff = zds->inBuff + zds->inBuffSize; zds->outBuffSize = neededOutBuffSize; } } zds->streamStage = zdss_read; /* fall-through */ case zdss_read: DEBUGLOG(5, "stage zdss_read"); { size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds); DEBUGLOG(5, "neededInSize = %u", (U32)neededInSize); if (neededInSize==0) { /* end of frame */ zds->streamStage = zdss_init; someMoreWork = 0; break; } if ((size_t)(iend-ip) >= neededInSize) { /* decode directly from src */ int const isSkipFrame = ZSTD_isSkipFrame(zds); size_t const decodedSize = ZSTD_decompressContinue(zds, 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->streamStage = zdss_flush; break; } } if (ip==iend) { someMoreWork = 0; break; } /* no more input */ zds->streamStage = zdss_load; /* fall-through */ case zdss_load: { size_t const neededInSize = ZSTD_nextSrcSizeToDecompress(zds); size_t const toLoad = neededInSize - zds->inPos; int const isSkipFrame = ZSTD_isSkipFrame(zds); size_t loadedSize; if (isSkipFrame) { loadedSize = MIN(toLoad, (size_t)(iend-ip)); } else { RETURN_ERROR_IF(toLoad > zds->inBuffSize - zds->inPos, 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 */ { size_t const decodedSize = ZSTD_decompressContinue(zds, 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->streamStage = zdss_read; break; } /* this was just a header */ zds->outEnd = zds->outStart + decodedSize; } } zds->streamStage = zdss_flush; /* fall-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->streamStage = zdss_read; if ( (zds->outBuffSize < zds->fParams.frameContentSize) && (zds->outStart + zds->fParams.blockSizeMax > zds->outBuffSize) ) { DEBUGLOG(5, "restart filling outBuff from beginning (left:%i, needed:%u)", (int)(zds->outBuffSize - zds->outStart), (U32)zds->fParams.blockSizeMax); zds->outStart = zds->outEnd = 0; } break; } } /* cannot complete flush */ someMoreWork = 0; break; default: assert(0); /* impossible */ RETURN_ERROR(GENERIC); /* some compiler require default to do something */ } } /* result */ input->pos = (size_t)(ip - (const char*)(input->src)); output->pos = (size_t)(op - (char*)(output->dst)); if ((ip==istart) && (op==ostart)) { /* no forward progress */ zds->noForwardProgress ++; if (zds->noForwardProgress >= ZSTD_NO_FORWARD_PROGRESS_MAX) { RETURN_ERROR_IF(op==oend, dstSize_tooSmall); RETURN_ERROR_IF(ip==iend, srcSize_wrong); assert(0); } } else { zds->noForwardProgress = 0; } { size_t nextSrcSizeHint = ZSTD_nextSrcSizeToDecompress(zds); if (!nextSrcSizeHint) { /* frame fully decoded */ if (zds->outEnd == zds->outStart) { /* output fully flushed */ if (zds->hostageByte) { if (input->pos >= input->size) { /* can't release hostage (not present) */ zds->streamStage = zdss_read; return 1; } input->pos++; /* release hostage */ } /* zds->hostageByte */ return 0; } /* zds->outEnd == zds->outStart */ 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==0 */ nextSrcSizeHint += ZSTD_blockHeaderSize * (ZSTD_nextInputType(zds) == ZSTDnit_block); /* preload header of next block */ assert(zds->inPos <= nextSrcSizeHint); nextSrcSizeHint -= zds->inPos; /* part already loaded*/ return nextSrcSizeHint; } } size_t ZSTD_decompressStream_simpleArgs ( ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, size_t* dstPos, const void* src, size_t srcSize, size_t* srcPos) { ZSTD_outBuffer output = { dst, dstCapacity, *dstPos }; ZSTD_inBuffer input = { src, srcSize, *srcPos }; /* ZSTD_compress_generic() will check validity of dstPos and srcPos */ size_t const cErr = ZSTD_decompressStream(dctx, &output, &input); *dstPos = output.pos; *srcPos = input.pos; return cErr; }