in cdk/extra/lz4/lib/lz4frame.c [1556:2058]
size_t LZ4F_decompress(LZ4F_dctx* dctx,
void* dstBuffer, size_t* dstSizePtr,
const void* srcBuffer, size_t* srcSizePtr,
const LZ4F_decompressOptions_t* decompressOptionsPtr)
{
LZ4F_decompressOptions_t optionsNull;
const BYTE* const srcStart = (const BYTE*)srcBuffer;
const BYTE* const srcEnd = srcStart + *srcSizePtr;
const BYTE* srcPtr = srcStart;
BYTE* const dstStart = (BYTE*)dstBuffer;
BYTE* const dstEnd = dstStart ? dstStart + *dstSizePtr : NULL;
BYTE* dstPtr = dstStart;
const BYTE* selectedIn = NULL;
unsigned doAnotherStage = 1;
size_t nextSrcSizeHint = 1;
DEBUGLOG(5, "LZ4F_decompress : %p,%u => %p,%u",
srcBuffer, (unsigned)*srcSizePtr, dstBuffer, (unsigned)*dstSizePtr);
if (dstBuffer == NULL) assert(*dstSizePtr == 0);
MEM_INIT(&optionsNull, 0, sizeof(optionsNull));
if (decompressOptionsPtr==NULL) decompressOptionsPtr = &optionsNull;
*srcSizePtr = 0;
*dstSizePtr = 0;
assert(dctx != NULL);
dctx->skipChecksum |= (decompressOptionsPtr->skipChecksums != 0); /* once set, disable for the remainder of the frame */
/* behaves as a state machine */
while (doAnotherStage) {
switch(dctx->dStage)
{
case dstage_getFrameHeader:
DEBUGLOG(6, "dstage_getFrameHeader");
if ((size_t)(srcEnd-srcPtr) >= maxFHSize) { /* enough to decode - shortcut */
size_t const hSize = LZ4F_decodeHeader(dctx, srcPtr, (size_t)(srcEnd-srcPtr)); /* will update dStage appropriately */
FORWARD_IF_ERROR(hSize);
srcPtr += hSize;
break;
}
dctx->tmpInSize = 0;
if (srcEnd-srcPtr == 0) return minFHSize; /* 0-size input */
dctx->tmpInTarget = minFHSize; /* minimum size to decode header */
dctx->dStage = dstage_storeFrameHeader;
/* fall-through */
case dstage_storeFrameHeader:
DEBUGLOG(6, "dstage_storeFrameHeader");
{ size_t const sizeToCopy = MIN(dctx->tmpInTarget - dctx->tmpInSize, (size_t)(srcEnd - srcPtr));
memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy);
dctx->tmpInSize += sizeToCopy;
srcPtr += sizeToCopy;
}
if (dctx->tmpInSize < dctx->tmpInTarget) {
nextSrcSizeHint = (dctx->tmpInTarget - dctx->tmpInSize) + BHSize; /* rest of header + nextBlockHeader */
doAnotherStage = 0; /* not enough src data, ask for some more */
break;
}
FORWARD_IF_ERROR( LZ4F_decodeHeader(dctx, dctx->header, dctx->tmpInTarget) ); /* will update dStage appropriately */
break;
case dstage_init:
DEBUGLOG(6, "dstage_init");
if (dctx->frameInfo.contentChecksumFlag) (void)XXH32_reset(&(dctx->xxh), 0);
/* internal buffers allocation */
{ size_t const bufferNeeded = dctx->maxBlockSize
+ ((dctx->frameInfo.blockMode==LZ4F_blockLinked) ? 128 KB : 0);
if (bufferNeeded > dctx->maxBufferSize) { /* tmp buffers too small */
dctx->maxBufferSize = 0; /* ensure allocation will be re-attempted on next entry*/
LZ4F_free(dctx->tmpIn, dctx->cmem);
dctx->tmpIn = (BYTE*)LZ4F_malloc(dctx->maxBlockSize + BFSize /* block checksum */, dctx->cmem);
RETURN_ERROR_IF(dctx->tmpIn == NULL, allocation_failed);
LZ4F_free(dctx->tmpOutBuffer, dctx->cmem);
dctx->tmpOutBuffer= (BYTE*)LZ4F_malloc(bufferNeeded, dctx->cmem);
RETURN_ERROR_IF(dctx->tmpOutBuffer== NULL, allocation_failed);
dctx->maxBufferSize = bufferNeeded;
} }
dctx->tmpInSize = 0;
dctx->tmpInTarget = 0;
dctx->tmpOut = dctx->tmpOutBuffer;
dctx->tmpOutStart = 0;
dctx->tmpOutSize = 0;
dctx->dStage = dstage_getBlockHeader;
/* fall-through */
case dstage_getBlockHeader:
if ((size_t)(srcEnd - srcPtr) >= BHSize) {
selectedIn = srcPtr;
srcPtr += BHSize;
} else {
/* not enough input to read cBlockSize field */
dctx->tmpInSize = 0;
dctx->dStage = dstage_storeBlockHeader;
}
if (dctx->dStage == dstage_storeBlockHeader) /* can be skipped */
case dstage_storeBlockHeader:
{ size_t const remainingInput = (size_t)(srcEnd - srcPtr);
size_t const wantedData = BHSize - dctx->tmpInSize;
size_t const sizeToCopy = MIN(wantedData, remainingInput);
memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy);
srcPtr += sizeToCopy;
dctx->tmpInSize += sizeToCopy;
if (dctx->tmpInSize < BHSize) { /* not enough input for cBlockSize */
nextSrcSizeHint = BHSize - dctx->tmpInSize;
doAnotherStage = 0;
break;
}
selectedIn = dctx->tmpIn;
} /* if (dctx->dStage == dstage_storeBlockHeader) */
/* decode block header */
{ U32 const blockHeader = LZ4F_readLE32(selectedIn);
size_t const nextCBlockSize = blockHeader & 0x7FFFFFFFU;
size_t const crcSize = dctx->frameInfo.blockChecksumFlag * BFSize;
if (blockHeader==0) { /* frameEnd signal, no more block */
DEBUGLOG(5, "end of frame");
dctx->dStage = dstage_getSuffix;
break;
}
if (nextCBlockSize > dctx->maxBlockSize) {
RETURN_ERROR(maxBlockSize_invalid);
}
if (blockHeader & LZ4F_BLOCKUNCOMPRESSED_FLAG) {
/* next block is uncompressed */
dctx->tmpInTarget = nextCBlockSize;
DEBUGLOG(5, "next block is uncompressed (size %u)", (U32)nextCBlockSize);
if (dctx->frameInfo.blockChecksumFlag) {
(void)XXH32_reset(&dctx->blockChecksum, 0);
}
dctx->dStage = dstage_copyDirect;
break;
}
/* next block is a compressed block */
dctx->tmpInTarget = nextCBlockSize + crcSize;
dctx->dStage = dstage_getCBlock;
if (dstPtr==dstEnd || srcPtr==srcEnd) {
nextSrcSizeHint = BHSize + nextCBlockSize + crcSize;
doAnotherStage = 0;
}
break;
}
case dstage_copyDirect: /* uncompressed block */
DEBUGLOG(6, "dstage_copyDirect");
{ size_t sizeToCopy;
if (dstPtr == NULL) {
sizeToCopy = 0;
} else {
size_t const minBuffSize = MIN((size_t)(srcEnd-srcPtr), (size_t)(dstEnd-dstPtr));
sizeToCopy = MIN(dctx->tmpInTarget, minBuffSize);
memcpy(dstPtr, srcPtr, sizeToCopy);
if (!dctx->skipChecksum) {
if (dctx->frameInfo.blockChecksumFlag) {
(void)XXH32_update(&dctx->blockChecksum, srcPtr, sizeToCopy);
}
if (dctx->frameInfo.contentChecksumFlag)
(void)XXH32_update(&dctx->xxh, srcPtr, sizeToCopy);
}
if (dctx->frameInfo.contentSize)
dctx->frameRemainingSize -= sizeToCopy;
/* history management (linked blocks only)*/
if (dctx->frameInfo.blockMode == LZ4F_blockLinked) {
LZ4F_updateDict(dctx, dstPtr, sizeToCopy, dstStart, 0);
} }
srcPtr += sizeToCopy;
dstPtr += sizeToCopy;
if (sizeToCopy == dctx->tmpInTarget) { /* all done */
if (dctx->frameInfo.blockChecksumFlag) {
dctx->tmpInSize = 0;
dctx->dStage = dstage_getBlockChecksum;
} else
dctx->dStage = dstage_getBlockHeader; /* new block */
break;
}
dctx->tmpInTarget -= sizeToCopy; /* need to copy more */
}
nextSrcSizeHint = dctx->tmpInTarget +
+(dctx->frameInfo.blockChecksumFlag ? BFSize : 0)
+ BHSize /* next header size */;
doAnotherStage = 0;
break;
/* check block checksum for recently transferred uncompressed block */
case dstage_getBlockChecksum:
DEBUGLOG(6, "dstage_getBlockChecksum");
{ const void* crcSrc;
if ((srcEnd-srcPtr >= 4) && (dctx->tmpInSize==0)) {
crcSrc = srcPtr;
srcPtr += 4;
} else {
size_t const stillToCopy = 4 - dctx->tmpInSize;
size_t const sizeToCopy = MIN(stillToCopy, (size_t)(srcEnd-srcPtr));
memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy);
dctx->tmpInSize += sizeToCopy;
srcPtr += sizeToCopy;
if (dctx->tmpInSize < 4) { /* all input consumed */
doAnotherStage = 0;
break;
}
crcSrc = dctx->header;
}
if (!dctx->skipChecksum) {
U32 const readCRC = LZ4F_readLE32(crcSrc);
U32 const calcCRC = XXH32_digest(&dctx->blockChecksum);
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
DEBUGLOG(6, "compare block checksum");
if (readCRC != calcCRC) {
DEBUGLOG(4, "incorrect block checksum: %08X != %08X",
readCRC, calcCRC);
RETURN_ERROR(blockChecksum_invalid);
}
#else
(void)readCRC;
(void)calcCRC;
#endif
} }
dctx->dStage = dstage_getBlockHeader; /* new block */
break;
case dstage_getCBlock:
DEBUGLOG(6, "dstage_getCBlock");
if ((size_t)(srcEnd-srcPtr) < dctx->tmpInTarget) {
dctx->tmpInSize = 0;
dctx->dStage = dstage_storeCBlock;
break;
}
/* input large enough to read full block directly */
selectedIn = srcPtr;
srcPtr += dctx->tmpInTarget;
if (0) /* always jump over next block */
case dstage_storeCBlock:
{ size_t const wantedData = dctx->tmpInTarget - dctx->tmpInSize;
size_t const inputLeft = (size_t)(srcEnd-srcPtr);
size_t const sizeToCopy = MIN(wantedData, inputLeft);
memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy);
dctx->tmpInSize += sizeToCopy;
srcPtr += sizeToCopy;
if (dctx->tmpInSize < dctx->tmpInTarget) { /* need more input */
nextSrcSizeHint = (dctx->tmpInTarget - dctx->tmpInSize)
+ (dctx->frameInfo.blockChecksumFlag ? BFSize : 0)
+ BHSize /* next header size */;
doAnotherStage = 0;
break;
}
selectedIn = dctx->tmpIn;
}
/* At this stage, input is large enough to decode a block */
/* First, decode and control block checksum if it exists */
if (dctx->frameInfo.blockChecksumFlag) {
assert(dctx->tmpInTarget >= 4);
dctx->tmpInTarget -= 4;
assert(selectedIn != NULL); /* selectedIn is defined at this stage (either srcPtr, or dctx->tmpIn) */
{ U32 const readBlockCrc = LZ4F_readLE32(selectedIn + dctx->tmpInTarget);
U32 const calcBlockCrc = XXH32(selectedIn, dctx->tmpInTarget, 0);
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
RETURN_ERROR_IF(readBlockCrc != calcBlockCrc, blockChecksum_invalid);
#else
(void)readBlockCrc;
(void)calcBlockCrc;
#endif
} }
/* decode directly into destination buffer if there is enough room */
if ( ((size_t)(dstEnd-dstPtr) >= dctx->maxBlockSize)
/* unless the dictionary is stored in tmpOut:
* in which case it's faster to decode within tmpOut
* to benefit from prefix speedup */
&& !(dctx->dict!= NULL && (const BYTE*)dctx->dict + dctx->dictSize == dctx->tmpOut) )
{
const char* dict = (const char*)dctx->dict;
size_t dictSize = dctx->dictSize;
int decodedSize;
assert(dstPtr != NULL);
if (dict && dictSize > 1 GB) {
/* overflow control : dctx->dictSize is an int, avoid truncation / sign issues */
dict += dictSize - 64 KB;
dictSize = 64 KB;
}
decodedSize = LZ4_decompress_safe_usingDict(
(const char*)selectedIn, (char*)dstPtr,
(int)dctx->tmpInTarget, (int)dctx->maxBlockSize,
dict, (int)dictSize);
RETURN_ERROR_IF(decodedSize < 0, decompressionFailed);
if ((dctx->frameInfo.contentChecksumFlag) && (!dctx->skipChecksum))
XXH32_update(&(dctx->xxh), dstPtr, (size_t)decodedSize);
if (dctx->frameInfo.contentSize)
dctx->frameRemainingSize -= (size_t)decodedSize;
/* dictionary management */
if (dctx->frameInfo.blockMode==LZ4F_blockLinked) {
LZ4F_updateDict(dctx, dstPtr, (size_t)decodedSize, dstStart, 0);
}
dstPtr += decodedSize;
dctx->dStage = dstage_getBlockHeader; /* end of block, let's get another one */
break;
}
/* not enough place into dst : decode into tmpOut */
/* manage dictionary */
if (dctx->frameInfo.blockMode == LZ4F_blockLinked) {
if (dctx->dict == dctx->tmpOutBuffer) {
/* truncate dictionary to 64 KB if too big */
if (dctx->dictSize > 128 KB) {
memcpy(dctx->tmpOutBuffer, dctx->dict + dctx->dictSize - 64 KB, 64 KB);
dctx->dictSize = 64 KB;
}
dctx->tmpOut = dctx->tmpOutBuffer + dctx->dictSize;
} else { /* dict not within tmpOut */
size_t const reservedDictSpace = MIN(dctx->dictSize, 64 KB);
dctx->tmpOut = dctx->tmpOutBuffer + reservedDictSpace;
} }
/* Decode block into tmpOut */
{ const char* dict = (const char*)dctx->dict;
size_t dictSize = dctx->dictSize;
int decodedSize;
if (dict && dictSize > 1 GB) {
/* the dictSize param is an int, avoid truncation / sign issues */
dict += dictSize - 64 KB;
dictSize = 64 KB;
}
decodedSize = LZ4_decompress_safe_usingDict(
(const char*)selectedIn, (char*)dctx->tmpOut,
(int)dctx->tmpInTarget, (int)dctx->maxBlockSize,
dict, (int)dictSize);
RETURN_ERROR_IF(decodedSize < 0, decompressionFailed);
if (dctx->frameInfo.contentChecksumFlag && !dctx->skipChecksum)
XXH32_update(&(dctx->xxh), dctx->tmpOut, (size_t)decodedSize);
if (dctx->frameInfo.contentSize)
dctx->frameRemainingSize -= (size_t)decodedSize;
dctx->tmpOutSize = (size_t)decodedSize;
dctx->tmpOutStart = 0;
dctx->dStage = dstage_flushOut;
}
/* fall-through */
case dstage_flushOut: /* flush decoded data from tmpOut to dstBuffer */
DEBUGLOG(6, "dstage_flushOut");
if (dstPtr != NULL) {
size_t const sizeToCopy = MIN(dctx->tmpOutSize - dctx->tmpOutStart, (size_t)(dstEnd-dstPtr));
memcpy(dstPtr, dctx->tmpOut + dctx->tmpOutStart, sizeToCopy);
/* dictionary management */
if (dctx->frameInfo.blockMode == LZ4F_blockLinked)
LZ4F_updateDict(dctx, dstPtr, sizeToCopy, dstStart, 1 /*withinTmp*/);
dctx->tmpOutStart += sizeToCopy;
dstPtr += sizeToCopy;
}
if (dctx->tmpOutStart == dctx->tmpOutSize) { /* all flushed */
dctx->dStage = dstage_getBlockHeader; /* get next block */
break;
}
/* could not flush everything : stop there, just request a block header */
doAnotherStage = 0;
nextSrcSizeHint = BHSize;
break;
case dstage_getSuffix:
RETURN_ERROR_IF(dctx->frameRemainingSize, frameSize_wrong); /* incorrect frame size decoded */
if (!dctx->frameInfo.contentChecksumFlag) { /* no checksum, frame is completed */
nextSrcSizeHint = 0;
LZ4F_resetDecompressionContext(dctx);
doAnotherStage = 0;
break;
}
if ((srcEnd - srcPtr) < 4) { /* not enough size for entire CRC */
dctx->tmpInSize = 0;
dctx->dStage = dstage_storeSuffix;
} else {
selectedIn = srcPtr;
srcPtr += 4;
}
if (dctx->dStage == dstage_storeSuffix) /* can be skipped */
case dstage_storeSuffix:
{ size_t const remainingInput = (size_t)(srcEnd - srcPtr);
size_t const wantedData = 4 - dctx->tmpInSize;
size_t const sizeToCopy = MIN(wantedData, remainingInput);
memcpy(dctx->tmpIn + dctx->tmpInSize, srcPtr, sizeToCopy);
srcPtr += sizeToCopy;
dctx->tmpInSize += sizeToCopy;
if (dctx->tmpInSize < 4) { /* not enough input to read complete suffix */
nextSrcSizeHint = 4 - dctx->tmpInSize;
doAnotherStage=0;
break;
}
selectedIn = dctx->tmpIn;
} /* if (dctx->dStage == dstage_storeSuffix) */
/* case dstage_checkSuffix: */ /* no direct entry, avoid initialization risks */
if (!dctx->skipChecksum) {
U32 const readCRC = LZ4F_readLE32(selectedIn);
U32 const resultCRC = XXH32_digest(&(dctx->xxh));
#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION
RETURN_ERROR_IF(readCRC != resultCRC, contentChecksum_invalid);
#else
(void)readCRC;
(void)resultCRC;
#endif
}
nextSrcSizeHint = 0;
LZ4F_resetDecompressionContext(dctx);
doAnotherStage = 0;
break;
case dstage_getSFrameSize:
if ((srcEnd - srcPtr) >= 4) {
selectedIn = srcPtr;
srcPtr += 4;
} else {
/* not enough input to read cBlockSize field */
dctx->tmpInSize = 4;
dctx->tmpInTarget = 8;
dctx->dStage = dstage_storeSFrameSize;
}
if (dctx->dStage == dstage_storeSFrameSize)
case dstage_storeSFrameSize:
{ size_t const sizeToCopy = MIN(dctx->tmpInTarget - dctx->tmpInSize,
(size_t)(srcEnd - srcPtr) );
memcpy(dctx->header + dctx->tmpInSize, srcPtr, sizeToCopy);
srcPtr += sizeToCopy;
dctx->tmpInSize += sizeToCopy;
if (dctx->tmpInSize < dctx->tmpInTarget) {
/* not enough input to get full sBlockSize; wait for more */
nextSrcSizeHint = dctx->tmpInTarget - dctx->tmpInSize;
doAnotherStage = 0;
break;
}
selectedIn = dctx->header + 4;
} /* if (dctx->dStage == dstage_storeSFrameSize) */
/* case dstage_decodeSFrameSize: */ /* no direct entry */
{ size_t const SFrameSize = LZ4F_readLE32(selectedIn);
dctx->frameInfo.contentSize = SFrameSize;
dctx->tmpInTarget = SFrameSize;
dctx->dStage = dstage_skipSkippable;
break;
}
case dstage_skipSkippable:
{ size_t const skipSize = MIN(dctx->tmpInTarget, (size_t)(srcEnd-srcPtr));
srcPtr += skipSize;
dctx->tmpInTarget -= skipSize;
doAnotherStage = 0;
nextSrcSizeHint = dctx->tmpInTarget;
if (nextSrcSizeHint) break; /* still more to skip */
/* frame fully skipped : prepare context for a new frame */
LZ4F_resetDecompressionContext(dctx);
break;
}
} /* switch (dctx->dStage) */
} /* while (doAnotherStage) */
/* preserve history within tmpOut whenever necessary */
LZ4F_STATIC_ASSERT((unsigned)dstage_init == 2);
if ( (dctx->frameInfo.blockMode==LZ4F_blockLinked) /* next block will use up to 64KB from previous ones */
&& (dctx->dict != dctx->tmpOutBuffer) /* dictionary is not already within tmp */
&& (dctx->dict != NULL) /* dictionary exists */
&& (!decompressOptionsPtr->stableDst) /* cannot rely on dst data to remain there for next call */
&& ((unsigned)(dctx->dStage)-2 < (unsigned)(dstage_getSuffix)-2) ) /* valid stages : [init ... getSuffix[ */
{
if (dctx->dStage == dstage_flushOut) {
size_t const preserveSize = (size_t)(dctx->tmpOut - dctx->tmpOutBuffer);
size_t copySize = 64 KB - dctx->tmpOutSize;
const BYTE* oldDictEnd = dctx->dict + dctx->dictSize - dctx->tmpOutStart;
if (dctx->tmpOutSize > 64 KB) copySize = 0;
if (copySize > preserveSize) copySize = preserveSize;
assert(dctx->tmpOutBuffer != NULL);
memcpy(dctx->tmpOutBuffer + preserveSize - copySize, oldDictEnd - copySize, copySize);
dctx->dict = dctx->tmpOutBuffer;
dctx->dictSize = preserveSize + dctx->tmpOutStart;
} else {
const BYTE* const oldDictEnd = dctx->dict + dctx->dictSize;
size_t const newDictSize = MIN(dctx->dictSize, 64 KB);
memcpy(dctx->tmpOutBuffer, oldDictEnd - newDictSize, newDictSize);
dctx->dict = dctx->tmpOutBuffer;
dctx->dictSize = newDictSize;
dctx->tmpOut = dctx->tmpOutBuffer + newDictSize;
}
}
*srcSizePtr = (size_t)(srcPtr - srcStart);
*dstSizePtr = (size_t)(dstPtr - dstStart);
return nextSrcSizeHint;
}