Pathological samples may result in literal section being incompressible.
This case is now detected,
and literal distribution is replaced by one that can be written into the dictionary.
This commit is contained in:
Yann Collet
2018-01-11 11:16:32 -08:00
parent 218e9fe0fc
commit e8093dde09
4 changed files with 38 additions and 17 deletions
+10 -8
View File
@@ -659,12 +659,13 @@ static int basicUnitTests(U32 seed, double compressibility)
/* Dictionary and dictBuilder tests */
{ ZSTD_CCtx* const cctx = ZSTD_createCCtx();
size_t dictSize = 16 KB;
void* dictBuffer = malloc(dictSize);
size_t const dictBufferCapacity = 16 KB;
void* dictBuffer = malloc(dictBufferCapacity);
size_t const totalSampleSize = 1 MB;
size_t const sampleUnitSize = 8 KB;
U32 const nbSamples = (U32)(totalSampleSize / sampleUnitSize);
size_t* const samplesSizes = (size_t*) malloc(nbSamples * sizeof(size_t));
size_t dictSize;
U32 dictID;
if (dictBuffer==NULL || samplesSizes==NULL) {
@@ -675,16 +676,17 @@ static int basicUnitTests(U32 seed, double compressibility)
DISPLAYLEVEL(4, "test%3i : dictBuilder on cyclic data : ", testNb++);
assert(compressedBufferSize >= totalSampleSize);
{ U32 u; for (u=0; u<totalSampleSize; u++) ((BYTE*)compressedBuffer)[u] = (BYTE)u; }
{ U32 u; for (u=0; u<totalSampleSize; u++) ((BYTE*)decodedBuffer)[u] = (BYTE)u; }
{ U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
dictSize = ZDICT_trainFromBuffer(dictBuffer, dictSize,
compressedBuffer, samplesSizes, nbSamples);
if (ZDICT_isError(dictSize)) goto _output_error;
DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)dictSize);
{ size_t const sDictSize = ZDICT_trainFromBuffer(dictBuffer, dictBufferCapacity,
decodedBuffer, samplesSizes, nbSamples);
if (ZDICT_isError(sDictSize)) goto _output_error;
DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)sDictSize);
}
DISPLAYLEVEL(4, "test%3i : dictBuilder : ", testNb++);
{ U32 u; for (u=0; u<nbSamples; u++) samplesSizes[u] = sampleUnitSize; }
dictSize = ZDICT_trainFromBuffer(dictBuffer, dictSize,
dictSize = ZDICT_trainFromBuffer(dictBuffer, dictBufferCapacity,
CNBuffer, samplesSizes, nbSamples);
if (ZDICT_isError(dictSize)) goto _output_error;
DISPLAYLEVEL(4, "OK, created dictionary of size %u \n", (U32)dictSize);