Create fuzzer tests for audio decoders

webrtc/test/fuzzers/audio_decoder_fuzzer.cc

+/*
+ *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "webrtc/test/fuzzers/audio_decoder_fuzzer.h"
+
+#include "webrtc/base/checks.h"
+#include "webrtc/modules/audio_coding/codecs/audio_decoder.h"
+
+namespace webrtc {
+namespace {
+size_t PacketSizeFromTwoBytes(const uint8_t* data, size_t size) {
+  if (size < 2)
+    return 0;
+  return static_cast<size_t>((data[0] << 8) + data[1]);
+}
+}  // namespace
+
+// This function reads two bytes from the beginning of |data|, interprets them
+// as the first packet length, and reads this many bytes if available. The
+// payload is inserted into the decoder, and the process continues until no more
+// data is available.
+void FuzzAudioDecoder(const uint8_t* data,
+                      size_t size,
+                      AudioDecoder* decoder,
+                      int sample_rate_hz,
+                      size_t max_decoded_bytes,
+                      int16_t* decoded) {
+  const uint8_t* data_ptr = data;
+  size_t remaining_size = size;
+  size_t packet_len = PacketSizeFromTwoBytes(data_ptr, remaining_size);
+  while (packet_len != 0 && packet_len <= remaining_size - 2) {
+    data_ptr += 2;
+    remaining_size -= 2;
+    AudioDecoder::SpeechType speech_type;
+    decoder->Decode(data_ptr, packet_len, sample_rate_hz, max_decoded_bytes,
+                    decoded, &speech_type);
+    data_ptr += packet_len;
+    remaining_size -= packet_len;
+    packet_len = PacketSizeFromTwoBytes(data_ptr, remaining_size);
+  }
+}
+}  // namespace webrtc