diff --git a/lib/compress/zstd_compress.c b/lib/compress/zstd_compress.c index 0232be0448d..95757972a5f 100644 --- a/lib/compress/zstd_compress.c +++ b/lib/compress/zstd_compress.c @@ -1390,8 +1390,15 @@ size_t ZSTD_estimateCCtxSize_usingCParams(ZSTD_compressionParameters cParams) static size_t ZSTD_estimateCCtxSize_internal(int compressionLevel) { - ZSTD_compressionParameters const cParams = ZSTD_getCParams_internal(compressionLevel, ZSTD_CONTENTSIZE_UNKNOWN, 0, ZSTD_cpm_noAttachDict); - return ZSTD_estimateCCtxSize_usingCParams(cParams); + int tier = 0; + size_t largestSize = 0; + static const unsigned long long srcSizeTiers[4] = {16 KB, 128 KB, 256 KB, ZSTD_CONTENTSIZE_UNKNOWN}; + for (; tier < 4; ++tier) { + /* Choose the set of cParams for a given level across all srcSizes that give the largest cctxSize */ + ZSTD_compressionParameters const cParams = ZSTD_getCParams_internal(compressionLevel, srcSizeTiers[tier], 0, ZSTD_cpm_noAttachDict); + largestSize = MAX(ZSTD_estimateCCtxSize_usingCParams(cParams), largestSize); + } + return largestSize; } size_t ZSTD_estimateCCtxSize(int compressionLevel) @@ -1399,6 +1406,7 @@ size_t ZSTD_estimateCCtxSize(int compressionLevel) int level; size_t memBudget = 0; for (level=MIN(compressionLevel, 1); level<=compressionLevel; level++) { + /* Ensure monotonically increasing memory usage as compression level increases */ size_t const newMB = ZSTD_estimateCCtxSize_internal(level); if (newMB > memBudget) memBudget = newMB; } diff --git a/tests/fuzzer.c b/tests/fuzzer.c index 5f707e027d5..1bc7f9c7ee4 100644 --- a/tests/fuzzer.c +++ b/tests/fuzzer.c @@ -3181,6 +3181,48 @@ static int basicUnitTests(U32 const seed, double compressibility) } DISPLAYLEVEL(3, "OK \n"); + DISPLAYLEVEL(3, "test%3i : check compression mem usage monotonicity over levels for estimateCCtxSize() : ", testNb++); + { + int level = 1; + size_t prevSize = 0; + for (; level < ZSTD_maxCLevel(); ++level) { + size_t const currSize = ZSTD_estimateCCtxSize(level); + if (prevSize > currSize) { + DISPLAYLEVEL(3, "Error! previous cctx size: %zu at level: %d is larger than current cctx size: %zu at level: %d", + prevSize, level-1, currSize, level); + goto _output_error; + } + prevSize = currSize; + } + } + DISPLAYLEVEL(3, "OK \n"); + + DISPLAYLEVEL(3, "test%3i : check estimateCCtxSize() always larger or equal to ZSTD_estimateCCtxSize_usingCParams() : ", testNb++); + { + size_t const kSizeIncrement = 2 KB; + int level = -3; + + for (; level <= ZSTD_maxCLevel(); ++level) { + size_t dictSize = 0; + for (; dictSize <= 256 KB; dictSize += 8 * kSizeIncrement) { + size_t srcSize = 2 KB; + for (; srcSize < 300 KB; srcSize += kSizeIncrement) { + ZSTD_compressionParameters const cParams = ZSTD_getCParams(level, srcSize, dictSize); + size_t const cctxSizeUsingCParams = ZSTD_estimateCCtxSize_usingCParams(cParams); + size_t const cctxSizeUsingLevel = ZSTD_estimateCCtxSize(level); + if (cctxSizeUsingLevel < cctxSizeUsingCParams + || ZSTD_isError(cctxSizeUsingCParams) + || ZSTD_isError(cctxSizeUsingLevel)) { + DISPLAYLEVEL(3, "error! l: %d dict: %zu srcSize: %zu cctx size cpar: %zu, cctx size level: %zu\n", + level, dictSize, srcSize, cctxSizeUsingCParams, cctxSizeUsingLevel); + goto _output_error; + } + } + } + } + } + DISPLAYLEVEL(3, "OK \n"); + #endif _end: