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Merge pull request #1297 from felixhandte/check-offset-table

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Fix Missing Offset Table Check
This commit is contained in:
Yann Collet
2018-08-24 17:36:44 -07:00
committed by GitHub
parent 3b56bb1e4c 37f17ee237
commit af23d39eb8
2 changed files with 64 additions and 10 deletions
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lib/compress/zstd_compress.c
+11 -10
View File
@@ -2248,13 +2248,6 @@ MEM_STATIC size_t ZSTD_compressSequences(seqStore_t* seqStorePtr,
if (cSize >= maxCSize) return 0; /* block not compressed */
}
/* We check that dictionaries have offset codes available for the first
* block. After the first block, the offcode table might not have large
* enough codes to represent the offsets in the data.
*/
if (nextEntropy->fse.offcode_repeatMode == FSE_repeat_valid)
nextEntropy->fse.offcode_repeatMode = FSE_repeat_check;
return cSize;
}
@@ -2393,12 +2386,20 @@ static size_t ZSTD_compressBlock_internal(ZSTD_CCtx* zc,
&zc->appliedParams,
dst, dstCapacity,
srcSize, zc->entropyWorkspace, zc->bmi2);
if (ZSTD_isError(cSize) || cSize == 0) return cSize;
/* confirm repcodes and entropy tables */
{ ZSTD_compressedBlockState_t* const tmp = zc->blockState.prevCBlock;
if (!ZSTD_isError(cSize) && cSize != 0) {
/* confirm repcodes and entropy tables */
ZSTD_compressedBlockState_t* const tmp = zc->blockState.prevCBlock;
zc->blockState.prevCBlock = zc->blockState.nextCBlock;
zc->blockState.nextCBlock = tmp;
}
/* We check that dictionaries have offset codes available for the first
* block. After the first block, the offcode table might not have large
* enough codes to represent the offsets in the data.
*/
if (zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode == FSE_repeat_valid)
zc->blockState.prevCBlock->entropy.fse.offcode_repeatMode = FSE_repeat_check;
return cSize;
}
}
tests/zstreamtest.c
+53
View File
@@ -1020,6 +1020,59 @@ static int basicUnitTests(U32 seed, double compressibility)
}
DISPLAYLEVEL(3, "OK \n");
DISPLAYLEVEL(3, "test%3i : dictionary + uncompressible block + reusing tables checks offset table validity: ", testNb++);
{ ZSTD_CDict* const cdict = ZSTD_createCDict_advanced(
dictionary.start, dictionary.filled,
ZSTD_dlm_byRef, ZSTD_dct_fullDict,
ZSTD_getCParams(3, 0, dictionary.filled),
ZSTD_defaultCMem);
const size_t inbufsize = 2 * 128 * 1024; /* 2 blocks */
const size_t outbufsize = ZSTD_compressBound(inbufsize);
size_t inbufpos = 0;
size_t cursegmentlen;
BYTE *inbuf = (BYTE *)malloc(inbufsize);
BYTE *outbuf = (BYTE *)malloc(outbufsize);
BYTE *checkbuf = (BYTE *)malloc(inbufsize);
size_t ret;
CHECK(cdict == NULL, "failed to alloc cdict");
CHECK(inbuf == NULL, "failed to alloc input buffer");
/* first block is uncompressible */
cursegmentlen = 128 * 1024;
RDG_genBuffer(inbuf + inbufpos, cursegmentlen, 0., 0., seed);
inbufpos += cursegmentlen;
/* second block is compressible */
cursegmentlen = 128 * 1024 - 256;
RDG_genBuffer(inbuf + inbufpos, cursegmentlen, 0.05, 0., seed);
inbufpos += cursegmentlen;
/* and includes a very long backref */
cursegmentlen = 128;
memcpy(inbuf + inbufpos, dictionary.start + 256, cursegmentlen);
inbufpos += cursegmentlen;
/* and includes a very long backref */
cursegmentlen = 128;
memcpy(inbuf + inbufpos, dictionary.start + 128, cursegmentlen);
inbufpos += cursegmentlen;
ret = ZSTD_compress_usingCDict(zc, outbuf, outbufsize, inbuf, inbufpos, cdict);
CHECK_Z(ret);
ret = ZSTD_decompress_usingDict(zd, checkbuf, inbufsize, outbuf, ret, dictionary.start, dictionary.filled);
CHECK_Z(ret);
CHECK(memcmp(inbuf, checkbuf, inbufpos), "start and finish buffers don't match");
ZSTD_freeCDict(cdict);
free(inbuf);
free(outbuf);
free(checkbuf);
}
DISPLAYLEVEL(3, "OK \n");
_end:
FUZ_freeDictionary(dictionary);
ZSTD_freeCStream(zc);