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[libzstd] Fix parameter selection for empty input 

ZSTD_compress() and friends would treat an empty input as an unknown size
when selecting parameters. Thus, they would drastically overallocate the
context. Tell ZSTD_getParams() that the source size is 1 when it is empty.
dev
Nick Terrell 2017-10-25 17:10:57 -07:00
parent 97dccbbb2b
commit 86b8134cad
2 changed files with 9 additions and 1 deletions
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2
lib/compress/zstd_compress.c
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@ -2213,7 +2213,7 @@ size_t ZSTD_compress_advanced_internal(
size_t ZSTD_compress_usingDict(ZSTD_CCtx* ctx, void* dst, size_t dstCapacity, const void* src, size_t srcSize,
const void* dict, size_t dictSize, int compressionLevel)
{
ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize, dict ? dictSize : 0);
ZSTD_parameters params = ZSTD_getParams(compressionLevel, srcSize ? srcSize : 1, dict ? dictSize : 0);
params.fParams.contentSizeFlag = 1;
return ZSTD_compress_internal(ctx, dst, dstCapacity, src, srcSize, dict, dictSize, params);
}

8
tests/fuzzer.c
View File

@ -359,6 +359,14 @@ static int basicUnitTests(U32 seed, double compressibility)
if (ZSTD_getErrorCode(r) != ZSTD_error_srcSize_wrong) goto _output_error; }
DISPLAYLEVEL(4, "OK \n");
DISPLAYLEVEL(4, "test%di : check CCtx size after compressing empty input : ", testNb++);
{ ZSTD_CCtx* cctx = ZSTD_createCCtx();
size_t const r = ZSTD_compressCCtx(cctx, compressedBuffer, compressedBufferSize, NULL, 0, 19);
if (ZSTD_isError(r)) goto _output_error;
if (ZSTD_sizeof_CCtx(cctx) > (1U << 20)) goto _output_error;
ZSTD_freeCCtx(cctx);
}
DISPLAYLEVEL(4, "OK \n");
/* Static CCtx tests */
#define STATIC_CCTX_LEVEL 3