1 files changed, 84 insertions, 0 deletions
diff --git a/src/zstd/tests/fuzz/fuzz_data_producer.c b/src/zstd/tests/fuzz/fuzz_data_producer.c
new file mode 100644
index 000000000..6518af309
--- /dev/null
+++ b/src/zstd/tests/fuzz/fuzz_data_producer.c
@@ -0,0 +1,84 @@
+/*
+ * Copyright (c) 2016-2020, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under both the BSD-style license (found in the
+ * LICENSE file in the root directory of this source tree) and the GPLv2 (found
+ * in the COPYING file in the root directory of this source tree).
+ * You may select, at your option, one of the above-listed licenses.
+ */
+
+#include "fuzz_data_producer.h"
+
+struct FUZZ_dataProducer_s{
+  const uint8_t *data;
+  size_t size;
+};
+
+FUZZ_dataProducer_t *FUZZ_dataProducer_create(const uint8_t *data, size_t size) {
+    FUZZ_dataProducer_t *producer = FUZZ_malloc(sizeof(FUZZ_dataProducer_t));
+
+    producer->data = data;
+    producer->size = size;
+    return producer;
+}
+
+void FUZZ_dataProducer_free(FUZZ_dataProducer_t *producer) { free(producer); }
+
+uint32_t FUZZ_dataProducer_uint32Range(FUZZ_dataProducer_t *producer, uint32_t min,
+                                  uint32_t max) {
+    FUZZ_ASSERT(min <= max);
+
+    uint32_t range = max - min;
+    uint32_t rolling = range;
+    uint32_t result = 0;
+
+    while (rolling > 0 && producer->size > 0) {
+      uint8_t next = *(producer->data + producer->size - 1);
+      producer->size -= 1;
+      result = (result << 8) | next;
+      rolling >>= 8;
+    }
+
+    if (range == 0xffffffff) {
+      return result;
+    }
+
+    return min + result % (range + 1);
+}
+
+uint32_t FUZZ_dataProducer_uint32(FUZZ_dataProducer_t *producer) {
+    return FUZZ_dataProducer_uint32Range(producer, 0, 0xffffffff);
+}
+
+int32_t FUZZ_dataProducer_int32Range(FUZZ_dataProducer_t *producer,
+                                    int32_t min, int32_t max)
+{
+    FUZZ_ASSERT(min <= max);
+
+    if (min < 0)
+      return (int)FUZZ_dataProducer_uint32Range(producer, 0, max - min) + min;
+
+    return FUZZ_dataProducer_uint32Range(producer, min, max);
+}
+
+size_t FUZZ_dataProducer_remainingBytes(FUZZ_dataProducer_t *producer){
+    return producer->size;
+}
+
+size_t FUZZ_dataProducer_contract(FUZZ_dataProducer_t *producer, size_t newSize)
+{
+    newSize = newSize > producer->size ? producer->size : newSize;
+
+    size_t remaining = producer->size - newSize;
+    producer->data = producer->data + remaining;
+    producer->size = newSize;
+    return remaining;
+}
+
+size_t FUZZ_dataProducer_reserveDataPrefix(FUZZ_dataProducer_t *producer)
+{
+    size_t producerSliceSize = FUZZ_dataProducer_uint32Range(
+                                  producer, 0, producer->size);
+    return FUZZ_dataProducer_contract(producer, producerSliceSize);
+}