Merge pull request #2616 from terrelln/deterministic-dict

[lib] Add ZSTD_c_deterministicRefPrefix

tests/fuzz/zstd_helpers.c

@@ -97,6 +97,7 @@ void FUZZ_setRandomParameters(ZSTD_CCtx *cctx, size_t srcSize, FUZZ_dataProducer
     setRand(cctx, ZSTD_c_literalCompressionMode, 0, 2, producer);
     setRand(cctx, ZSTD_c_forceAttachDict, 0, 2, producer);
     setRand(cctx, ZSTD_c_splitBlocks, 0, 1, producer);
+    setRand(cctx, ZSTD_c_deterministicRefPrefix, 0, 1, producer);
     if (FUZZ_dataProducer_uint32Range(producer, 0, 1) == 0) {
       setRand(cctx, ZSTD_c_srcSizeHint, ZSTD_SRCSIZEHINT_MIN, 2 * srcSize, producer);
     }

tests/fuzzer.c

@@ -766,6 +766,50 @@ static int basicUnitTests(U32 const seed, double compressibility)
     }
     DISPLAYLEVEL(3, "OK \n");
 
+    DISPLAYLEVEL(3, "test%3i : testing dict compression for determinism : ", testNb++);
+    {
+        size_t const testSize = 1024;
+        ZSTD_CCtx* const cctx = ZSTD_createCCtx();
+        ZSTD_DCtx* const dctx = ZSTD_createDCtx();
+        char* dict = (char*)malloc(2 * testSize);
+        int ldmEnabled, level;
+
+        RDG_genBuffer(dict, testSize, 0.5, 0.5, seed);
+        RDG_genBuffer(CNBuffer, testSize, 0.6, 0.6, seed);
+        memcpy(dict + testSize, CNBuffer, testSize);
+        for (level = 1; level <= 5; ++level) {
+            for (ldmEnabled = 0; ldmEnabled <= 1; ++ldmEnabled) {
+                size_t cSize0;
+                XXH64_hash_t compressedChecksum0;
+
+                CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_checksumFlag, 1));
+                CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_compressionLevel, level));
+                CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_enableLongDistanceMatching, ldmEnabled));
+                CHECK_Z(ZSTD_CCtx_setParameter(cctx, ZSTD_c_deterministicRefPrefix, 1));
+
+                CHECK_Z(ZSTD_CCtx_refPrefix(cctx, dict, testSize));
+                cSize = ZSTD_compress2(cctx, compressedBuffer, compressedBufferSize, CNBuffer, testSize);
+                CHECK_Z(cSize);
+                CHECK_Z(ZSTD_decompress_usingDict(dctx, decodedBuffer, testSize, compressedBuffer, cSize, dict, testSize));
+
+                cSize0 = cSize;
+                compressedChecksum0 = XXH64(compressedBuffer, cSize, 0);
+
+                CHECK_Z(ZSTD_CCtx_refPrefix(cctx, dict, testSize));
+                cSize = ZSTD_compress2(cctx, compressedBuffer, compressedBufferSize, dict + testSize, testSize);
+                CHECK_Z(cSize);
+
+                if (cSize != cSize0) goto _output_error;
+                if (XXH64(compressedBuffer, cSize, 0) != compressedChecksum0) goto _output_error;
+            }
+        }
+
+        ZSTD_freeCCtx(cctx);
+        ZSTD_freeDCtx(dctx);
+        free(dict);
+    }
+    DISPLAYLEVEL(3, "OK \n");
+
     DISPLAYLEVEL(3, "test%3i : LDM + opt parser with small uncompressible block ", testNb++);
     {   ZSTD_CCtx* cctx = ZSTD_createCCtx();
         ZSTD_DCtx* dctx = ZSTD_createDCtx();

tests/zstreamtest.c

@@ -2215,6 +2215,7 @@ static int fuzzerTests_newAPI(U32 seed, int nbTests, int startTest,
                 }
 
                 if (FUZ_rand(&lseed) & 1) CHECK_Z( setCCtxParameter(zc, cctxParams, ZSTD_c_forceMaxWindow, FUZ_rand(&lseed) & 1, opaqueAPI) );
+                if (FUZ_rand(&lseed) & 1) CHECK_Z( setCCtxParameter(zc, cctxParams, ZSTD_c_deterministicRefPrefix, FUZ_rand(&lseed) & 1, opaqueAPI) );
 
                 /* Apply parameters */
                 if (opaqueAPI) {