feature: Add a roundtrip fuzz testing harness

fuzz/dfuzz.cc

@@ -0,0 +1,64 @@
+/******************************************************************************
+ *
+ *  Copyright 2022 Google LLC
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at:
+ *
+ *  http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ ******************************************************************************/
+
+#include <lc3_cpp.h>
+#include <fuzzer/FuzzedDataProvider.h>
+
+using namespace lc3;
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size)
+{
+  const int dt_list[] = { 7500, 10000 };
+  const int sr_list[] = { 8000, 16000, 24000, 32000, 48000 };
+
+  FuzzedDataProvider fdp(data, size);
+
+  int dt_us = fdp.PickValueInArray(dt_list);
+  int sr_hz = fdp.PickValueInArray(sr_list);
+  int nchannels =fdp.PickValueInArray({1, 2});
+
+  int sr_pcm_hz = fdp.PickValueInArray(sr_list);
+  if (sr_pcm_hz < sr_hz)
+    sr_pcm_hz = 0;
+
+  Decoder dec(dt_us, sr_hz, sr_pcm_hz, nchannels);
+
+  int frame_size = fdp.ConsumeIntegralInRange(
+    LC3_MIN_FRAME_BYTES, LC3_MAX_FRAME_BYTES);
+
+  PcmFormat fmt = fdp.PickValueInArray(
+    { PcmFormat::kS16, PcmFormat::kS24,
+      PcmFormat::kS24In3Le, PcmFormat::kF32 });
+
+  int frame_samples = dec.GetFrameSamples();
+
+  int sample_bytes =
+    fmt == PcmFormat::kS16 ? sizeof(int16_t) :
+    fmt == PcmFormat::kS24 ? sizeof(int32_t) :
+    fmt == PcmFormat::kS24In3Le ? sizeof(uint8_t) * 3 :
+    fmt == PcmFormat::kF32 ? sizeof(float) : 0;
+
+  if (fdp.remaining_bytes() < frame_size * nchannels)
+    return -1;
+
+  dec.Decode(
+    fdp.ConsumeBytes<uint8_t>(nchannels * frame_size).data(), frame_size,
+    fmt, std::vector<uint8_t>(nchannels * frame_samples * sample_bytes).data());
+
+  return 0;
+}