Seperating fuzz data producer api impl and header, using data producer on the easy fuzzers

1 files changed, 32 insertions, 0 deletions

diff --git a/ossfuzz/fuzz_data_producer.c b/ossfuzz/fuzz_data_producer.c
new file mode 100644
index 0000000..ae07575
--- /dev/null
+++ b/ossfuzz/fuzz_data_producer.c
@@ -0,0 +1,32 @@
+#include "fuzz_data_producer.h"
+
+FUZZ_dataProducer_t *FUZZ_dataProducer_create(const uint8_t *data, size_t size) {
+  FUZZ_dataProducer_t *producer = 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_uint32(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);
+}