diff options
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/lz4frame.c | 24 | ||||
| -rw-r--r-- | lib/lz4frame.h | 8 |
2 files changed, 21 insertions, 11 deletions
diff --git a/lib/lz4frame.c b/lib/lz4frame.c index fa987d7..ffd0e9c 100644 --- a/lib/lz4frame.c +++ b/lib/lz4frame.c @@ -1222,6 +1222,7 @@ struct LZ4F_dctx_s { size_t tmpOutStart; XXH32_state_t xxh; XXH32_state_t blockChecksum; + int skipChecksum; BYTE header[LZ4F_HEADER_SIZE_MAX]; }; /* typedef'd to LZ4F_dctx in lz4frame.h */ @@ -1275,6 +1276,7 @@ void LZ4F_resetDecompressionContext(LZ4F_dctx* dctx) dctx->dStage = dstage_getFrameHeader; dctx->dict = NULL; dctx->dictSize = 0; + dctx->skipChecksum = 0; } @@ -1537,7 +1539,6 @@ static void LZ4F_updateDict(LZ4F_dctx* dctx, } - /*! LZ4F_decompress() : * Call this function repetitively to regenerate compressed data in srcBuffer. * The function will attempt to decode up to *srcSizePtr bytes from srcBuffer @@ -1581,6 +1582,7 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, *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 */ @@ -1711,11 +1713,13 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, size_t const minBuffSize = MIN((size_t)(srcEnd-srcPtr), (size_t)(dstEnd-dstPtr)); sizeToCopy = MIN(dctx->tmpInTarget, minBuffSize); memcpy(dstPtr, srcPtr, sizeToCopy); - if (dctx->frameInfo.blockChecksumFlag) { - (void)XXH32_update(&dctx->blockChecksum, 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.contentChecksumFlag) - (void)XXH32_update(&dctx->xxh, srcPtr, sizeToCopy); if (dctx->frameInfo.contentSize) dctx->frameRemainingSize -= sizeToCopy; @@ -1761,7 +1765,8 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, } crcSrc = dctx->header; } - { U32 const readCRC = LZ4F_readLE32(crcSrc); + 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"); @@ -1837,7 +1842,7 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, (int)dctx->tmpInTarget, (int)dctx->maxBlockSize, dict, (int)dictSize); RETURN_ERROR_IF(decodedSize < 0, decompressionFailed); - if (dctx->frameInfo.contentChecksumFlag) + if ((dctx->frameInfo.contentChecksumFlag) && (!dctx->skipChecksum)) XXH32_update(&(dctx->xxh), dstPtr, (size_t)decodedSize); if (dctx->frameInfo.contentSize) dctx->frameRemainingSize -= (size_t)decodedSize; @@ -1880,7 +1885,7 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, (int)dctx->tmpInTarget, (int)dctx->maxBlockSize, dict, (int)dictSize); RETURN_ERROR_IF(decodedSize < 0, decompressionFailed); - if (dctx->frameInfo.contentChecksumFlag) + if (dctx->frameInfo.contentChecksumFlag && !dctx->skipChecksum) XXH32_update(&(dctx->xxh), dctx->tmpOut, (size_t)decodedSize); if (dctx->frameInfo.contentSize) dctx->frameRemainingSize -= (size_t)decodedSize; @@ -1945,7 +1950,8 @@ size_t LZ4F_decompress(LZ4F_dctx* dctx, } /* if (dctx->dStage == dstage_storeSuffix) */ /* case dstage_checkSuffix: */ /* no direct entry, avoid initialization risks */ - { U32 const readCRC = LZ4F_readLE32(selectedIn); + 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); diff --git a/lib/lz4frame.h b/lib/lz4frame.h index 1c2d0dd..1bdf6c4 100644 --- a/lib/lz4frame.h +++ b/lib/lz4frame.h @@ -355,8 +355,12 @@ typedef struct LZ4F_dctx_s LZ4F_dctx; /* incomplete type */ typedef LZ4F_dctx* LZ4F_decompressionContext_t; /* compatibility with previous API versions */ typedef struct { - unsigned stableDst; /* pledges that last 64KB decompressed data will remain available unmodified. This optimization skips storage operations in tmp buffers. */ - unsigned reserved[3]; /* must be set to zero for forward compatibility */ + unsigned stableDst; /* pledges that last 64KB decompressed data will remain available unmodified between invocations. + * This optimization skips storage operations in tmp buffers. */ + unsigned skipChecksums; /* disable checksum calculation and verification, even when one is present in frame, to save CPU time. + * Setting this option to 1 once disables all checksums for the rest of the frame. */ + unsigned reserved1; /* must be set to zero for forward compatibility */ + unsigned reserved0; /* idem */ } LZ4F_decompressOptions_t; |