ddidderr/zstd-rs
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new frame end, 32-bits checksums

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This commit is contained in:
Yann Collet
2016-07-28 00:55:43 +02:00
parent d4180cad9c
commit c991cc1828
6 changed files with 160 additions and 111 deletions
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lib/decompress/zstd_decompress.c
+69 -34
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@@ -105,6 +105,7 @@ static void ZSTD_copy4(void* dst, const void* src) { memcpy(dst, src, 4); }
***************************************************************/
typedef enum { ZSTDds_getFrameHeaderSize, ZSTDds_decodeFrameHeader,
ZSTDds_decodeBlockHeader, ZSTDds_decompressBlock,
ZSTDds_decompressLastBlock, ZSTDds_checkChecksum,
ZSTDds_decodeSkippableHeader, ZSTDds_skipFrame } ZSTD_dStage;
struct ZSTD_DCtx_s
@@ -131,6 +132,7 @@ struct ZSTD_DCtx_s
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_static.h" */
@@ -318,6 +320,7 @@ static size_t ZSTD_decodeFrameHeader(ZSTD_DCtx* dctx, const void* src, size_t sr
typedef struct
{
blockType_e blockType;
U32 lastBlock;
U32 origSize;
} blockProperties_t;
@@ -327,11 +330,12 @@ size_t ZSTD_getcBlockSize(const void* src, size_t srcSize, blockProperties_t* bp
{
if (srcSize < ZSTD_blockHeaderSize) return ERROR(srcSize_wrong);
{ U32 const cBlockHeader = MEM_readLE24(src);
U32 const cSize = cBlockHeader >> 2;
bpPtr->blockType = (blockType_e)(cBlockHeader & 3);
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_end) return 0;
if (bpPtr->blockType == bt_rle) return 1;
if (bpPtr->blockType == bt_reserved) return ERROR(corruption_detected);
return cSize;
}
}
@@ -345,6 +349,14 @@ static size_t ZSTD_copyRawBlock(void* dst, size_t dstCapacity, const void* src,
}
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,
@@ -889,29 +901,29 @@ static size_t ZSTD_decompressFrame(ZSTD_DCtx* dctx,
case bt_rle :
decodedSize = ZSTD_generateNxBytes(op, oend-op, *ip, blockProperties.origSize);
break;
case bt_end :
/* end of frame */
if (remainingSize) return ERROR(srcSize_wrong);
if (dctx->fParams.checksumFlag) {
U64 const h64 = XXH64_digest(&dctx->xxhState);
U32 const h32 = (U32)(h64>>11) & ((1<<22)-1);
U32 const check32 = MEM_readLE24(src) >> 2;
if (check32 != h32) return ERROR(checksum_wrong);
}
decodedSize = 0;
break;
case bt_reserved :
default:
return ERROR(GENERIC); /* impossible */
return ERROR(corruption_detected);
}
if (blockProperties.blockType == bt_end) break; /* bt_end */
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;
}
@@ -1022,22 +1034,29 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
{ blockProperties_t bp;
size_t const cBlockSize = ZSTD_getcBlockSize(src, ZSTD_blockHeaderSize, &bp);
if (ZSTD_isError(cBlockSize)) return cBlockSize;
if (bp.blockType == bt_end) {
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) {
U64 const h64 = XXH64_digest(&dctx->xxhState);
U32 const h32 = (U32)(h64>>11) & ((1<<22)-1);
U32 const check32 = MEM_readLE24(src) >> 2;
if (check32 != h32) return ERROR(checksum_wrong);
dctx->expected = 4;
dctx->stage = ZSTDds_checkChecksum;
} else {
dctx->expected = 0; /* end of frame */
dctx->stage = ZSTDds_getFrameHeaderSize;
}
dctx->expected = 0;
dctx->stage = ZSTDds_getFrameHeaderSize;
} else {
dctx->expected = cBlockSize;
dctx->bType = bp.blockType;
dctx->stage = ZSTDds_decompressBlock;
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)
@@ -1049,21 +1068,37 @@ size_t ZSTD_decompressContinue(ZSTD_DCtx* dctx, void* dst, size_t dstCapacity, c
rSize = ZSTD_copyRawBlock(dst, dstCapacity, src, srcSize);
break;
case bt_rle :
return ERROR(GENERIC); /* not yet handled */
break;
case bt_end : /* should never happen (filtered at phase 1) */
rSize = 0;
rSize = ZSTD_setRleBlock(dst, dstCapacity, src, srcSize, dctx->rleSize);
break;
case bt_reserved : /* should never happen */
default:
return ERROR(GENERIC); /* impossible */
return ERROR(corruption_detected);
}
dctx->stage = ZSTDds_decodeBlockHeader;
dctx->expected = ZSTD_blockHeaderSize;
dctx->previousDstEnd = (char*)dst + rSize;
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 = 0;
dctx->stage = ZSTDds_checkChecksum;
}
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_min, src, dctx->expected);
dctx->expected = MEM_readLE32(dctx->headerBuffer + 4);