diff options
| -rw-r--r-- | lib/lz4frame.c | 104 |
1 files changed, 54 insertions, 50 deletions
diff --git a/lib/lz4frame.c b/lib/lz4frame.c index 166d583..4df404c 100644 --- a/lib/lz4frame.c +++ b/lib/lz4frame.c @@ -1253,29 +1253,33 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, 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; - } - { size_t const hSize = LZ4F_decodeHeader(dctx, dctx->header, dctx->tmpInTarget); /* will update dStage appropriately */ - if (LZ4F_isError(hSize)) return hSize; - } + } + 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; } + { size_t const hSize = LZ4F_decodeHeader(dctx, dctx->header, dctx->tmpInTarget); /* will update dStage appropriately */ + if (LZ4F_isError(hSize)) return hSize; + } + break; case dstage_init: if (dctx->frameInfo.contentChecksumFlag) XXH32_reset(&(dctx->xxh), 0); /* internal buffers allocation */ - { size_t const bufferNeeded = dctx->maxBlockSize + ((dctx->frameInfo.blockMode==LZ4F_blockLinked) * 128 KB) + 4 /* block checksum */; + { size_t const bufferNeeded = dctx->maxBlockSize + + ((dctx->frameInfo.blockMode==LZ4F_blockLinked) * 128 KB) + + 4 /* block checksum */; if (bufferNeeded > dctx->maxBufferSize) { /* tmp buffers too small */ dctx->maxBufferSize = 0; /* ensure allocation will be re-attempted on next entry*/ FREEMEM(dctx->tmpIn); dctx->tmpIn = (BYTE*)ALLOCATOR(dctx->maxBlockSize); - if (dctx->tmpIn == NULL) return err0r(LZ4F_ERROR_allocation_failed); + if (dctx->tmpIn == NULL) + return err0r(LZ4F_ERROR_allocation_failed); FREEMEM(dctx->tmpOutBuffer); dctx->tmpOutBuffer= (BYTE*)ALLOCATOR(bufferNeeded); - if (dctx->tmpOutBuffer== NULL) return err0r(LZ4F_ERROR_allocation_failed); + if (dctx->tmpOutBuffer== NULL) + return err0r(LZ4F_ERROR_allocation_failed); dctx->maxBufferSize = bufferNeeded; } } dctx->tmpInSize = 0; @@ -1299,18 +1303,20 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, if (dctx->dStage == dstage_storeBlockHeader) /* can be skipped */ case dstage_storeBlockHeader: - { size_t sizeToCopy = BHSize - dctx->tmpInSize; - if (sizeToCopy > (size_t)(srcEnd - srcPtr)) sizeToCopy = srcEnd - srcPtr; + { 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 */ { size_t const nextCBlockSize = LZ4F_readLE32(selectedIn) & 0x7FFFFFFFU; @@ -1414,7 +1420,9 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, break; case dstage_storeCBlock: - { size_t const sizeToCopy = MIN(dctx->tmpInTarget - dctx->tmpInSize, (size_t)(srcEnd-srcPtr)); + { 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; @@ -1465,7 +1473,6 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, case dstage_decodeCBlock_intoTmp: /* not enough place into dst : decode into tmpOut */ - /* ensure enough place for tmpOut */ if (dctx->frameInfo.blockMode == LZ4F_blockLinked) { if (dctx->dict == dctx->tmpOutBuffer) { @@ -1518,29 +1525,27 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, } case dstage_getSuffix: - { size_t const suffixSize = dctx->frameInfo.contentChecksumFlag * 4; - if (dctx->frameRemainingSize) - return err0r(LZ4F_ERROR_frameSize_wrong); /* incorrect frame size decoded */ - if (suffixSize == 0) { /* frame 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->frameRemainingSize) + return err0r(LZ4F_ERROR_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 sizeToCopy = 4 - dctx->tmpInSize; - if (sizeToCopy > (size_t)(srcEnd - srcPtr)) sizeToCopy = srcEnd - srcPtr; + { 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; @@ -1550,7 +1555,7 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, break; } selectedIn = dctx->tmpIn; - } + } /* if (dctx->dStage == dstage_storeSuffix) */ /* case dstage_checkSuffix: */ /* no direct call, avoid scan-build warning */ { U32 const readCRC = LZ4F_readLE32(selectedIn); @@ -1589,7 +1594,7 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, break; } selectedIn = dctx->header + 4; - } + } /* if (dctx->dStage == dstage_storeSFrameSize) */ /* case dstage_decodeSFrameSize: */ /* no direct access */ { size_t const SFrameSize = LZ4F_readLE32(selectedIn); @@ -1606,22 +1611,22 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, 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; } } - } - - /* preserve history within tmp if necessary */ - if ( (dctx->frameInfo.blockMode==LZ4F_blockLinked) - && (dctx->dict != dctx->tmpOutBuffer) - && (dctx->dStage != dstage_getFrameHeader) - && (dctx->dStage != dstage_storeFrameHeader) - && (!decompressOptionsPtr->stableDst) - && ((unsigned)(dctx->dStage-1) < (unsigned)(dstage_getSuffix-1)) ) + } /* while (doAnotherStage) */ + + /* preserve history within tmp 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 */ + && (!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 preserveSize = dctx->tmpOut - dctx->tmpOutBuffer; + size_t const preserveSize = 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; @@ -1632,9 +1637,8 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, dctx->dict = dctx->tmpOutBuffer; dctx->dictSize = preserveSize + dctx->tmpOutStart; } else { - size_t newDictSize = dctx->dictSize; - const BYTE* oldDictEnd = dctx->dict + dctx->dictSize; - if ((newDictSize) > 64 KB) newDictSize = 64 KB; + const BYTE* const oldDictEnd = dctx->dict + dctx->dictSize; + size_t const newDictSize = MIN(dctx->dictSize, 64 KB); memcpy(dctx->tmpOutBuffer, oldDictEnd - newDictSize, newDictSize); |