[Fuzz] Improve data generation #1723

tests/fuzz/simple_decompress.c

@@ -17,13 +17,14 @@
 #include <stdio.h>
 #include "fuzz_helpers.h"
 #include "zstd.h"
+#include "fuzz_data_producer.h"
 
 static ZSTD_DCtx *dctx = NULL;
 
 int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
 {
 
-    uint32_t seed = FUZZ_seed(&src, &size);
+    FUZZ_dataProducer_t *producer = FUZZ_dataProducer_create(src, size);
     int i;
     if (!dctx) {
         dctx = ZSTD_createDCtx();
@@ -31,13 +32,15 @@ int LLVMFuzzerTestOneInput(const uint8_t *src, size_t size)
     }
     /* Run it 10 times over 10 output sizes. Reuse the context. */
     for (i = 0; i < 10; ++i) {
-        size_t const bufSize = FUZZ_rand32(&seed, 0, 2 * size);
+        size_t const bufSize = FUZZ_dataProducer_uint32Range(producer, 0, 2 * size);
         void* rBuf = malloc(bufSize);
         FUZZ_ASSERT(rBuf);
         ZSTD_decompressDCtx(dctx, rBuf, bufSize, src, size);
         free(rBuf);
     }
 
+    FUZZ_dataProducer_free(producer);
+
 #ifndef STATEFUL_FUZZING
     ZSTD_freeDCtx(dctx); dctx = NULL;
 #endif