add libaudioprocessing_resampler_fuzzer

This is based on the code from test-resampler.cpp. I simplify out some
bits and use the data from LibFuzzer as the input audio.

Test: ran fuzzer locally on-device
Change-Id: I1ed732698feccd4a644a1a8eea4e3862a025e11a
diff --git a/media/libaudioprocessing/tests/fuzzer/Android.bp b/media/libaudioprocessing/tests/fuzzer/Android.bp
new file mode 100644
index 0000000..1df47b7
--- /dev/null
+++ b/media/libaudioprocessing/tests/fuzzer/Android.bp
@@ -0,0 +1,10 @@
+cc_fuzz {
+  name: "libaudioprocessing_resampler_fuzzer",
+  srcs: [
+    "libaudioprocessing_resampler_fuzzer.cpp",
+  ],
+  defaults: ["libaudioprocessing_test_defaults"],
+  static_libs: [
+    "libsndfile",
+  ],
+}
diff --git a/media/libaudioprocessing/tests/fuzzer/libaudioprocessing_resampler_fuzzer.cpp b/media/libaudioprocessing/tests/fuzzer/libaudioprocessing_resampler_fuzzer.cpp
new file mode 100644
index 0000000..938c610
--- /dev/null
+++ b/media/libaudioprocessing/tests/fuzzer/libaudioprocessing_resampler_fuzzer.cpp
@@ -0,0 +1,188 @@
+/*
+ * Copyright (C) 2019 The Android Open Source Project
+ *
+ * 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 <android-base/macros.h>
+#include <audio_utils/primitives.h>
+#include <audio_utils/sndfile.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <math.h>
+#include <media/AudioBufferProvider.h>
+#include <media/AudioResampler.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <time.h>
+#include <unistd.h>
+#include <utils/Vector.h>
+
+#include <memory>
+
+using namespace android;
+
+const int MAX_FRAMES = 10;
+const int MIN_FREQ = 1e3;
+const int MAX_FREQ = 100e3;
+
+const AudioResampler::src_quality qualities[] = {
+    AudioResampler::DEFAULT_QUALITY,
+    AudioResampler::LOW_QUALITY,
+    AudioResampler::MED_QUALITY,
+    AudioResampler::HIGH_QUALITY,
+    AudioResampler::VERY_HIGH_QUALITY,
+    AudioResampler::DYN_LOW_QUALITY,
+    AudioResampler::DYN_MED_QUALITY,
+    AudioResampler::DYN_HIGH_QUALITY,
+};
+
+class Provider : public AudioBufferProvider {
+  const void* mAddr;        // base address
+  const size_t mNumFrames;  // total frames
+  const size_t mFrameSize;  // size of each frame in bytes
+  size_t mNextFrame;        // index of next frame to provide
+  size_t mUnrel;            // number of frames not yet released
+ public:
+  Provider(const void* addr, size_t frames, size_t frameSize)
+      : mAddr(addr),
+        mNumFrames(frames),
+        mFrameSize(frameSize),
+        mNextFrame(0),
+        mUnrel(0) {}
+  status_t getNextBuffer(Buffer* buffer) override {
+    if (buffer->frameCount > mNumFrames - mNextFrame) {
+      buffer->frameCount = mNumFrames - mNextFrame;
+    }
+    mUnrel = buffer->frameCount;
+    if (buffer->frameCount > 0) {
+      buffer->raw = (char*)mAddr + mFrameSize * mNextFrame;
+      return NO_ERROR;
+    } else {
+      buffer->raw = nullptr;
+      return NOT_ENOUGH_DATA;
+    }
+  }
+  virtual void releaseBuffer(Buffer* buffer) {
+    if (buffer->frameCount > mUnrel) {
+      mNextFrame += mUnrel;
+      mUnrel = 0;
+    } else {
+      mNextFrame += buffer->frameCount;
+      mUnrel -= buffer->frameCount;
+    }
+    buffer->frameCount = 0;
+    buffer->raw = nullptr;
+  }
+  void reset() { mNextFrame = 0; }
+};
+
+audio_format_t chooseFormat(AudioResampler::src_quality quality,
+                            uint8_t input_byte) {
+  switch (quality) {
+    case AudioResampler::DYN_LOW_QUALITY:
+    case AudioResampler::DYN_MED_QUALITY:
+    case AudioResampler::DYN_HIGH_QUALITY:
+      if (input_byte % 2) {
+        return AUDIO_FORMAT_PCM_FLOAT;
+      }
+      FALLTHROUGH_INTENDED;
+    default:
+      return AUDIO_FORMAT_PCM_16_BIT;
+  }
+}
+
+int parseValue(const uint8_t* src, int index, void* dst, size_t size) {
+  memcpy(dst, &src[index], size);
+  return size;
+}
+
+bool validFreq(int freq) { return freq > MIN_FREQ && freq < MAX_FREQ; }
+
+extern "C" int LLVMFuzzerTestOneInput(const uint8_t* data, size_t size) {
+  int input_freq = 0;
+  int output_freq = 0;
+  int input_channels = 0;
+
+  float left_volume = 0;
+  float right_volume = 0;
+
+  size_t metadata_size = 2 + 3 * sizeof(int) + 2 * sizeof(float);
+  if (size < metadata_size) {
+    // not enough data to set options
+    return 0;
+  }
+
+  AudioResampler::src_quality quality = qualities[data[0] % 8];
+  audio_format_t format = chooseFormat(quality, data[1]);
+
+  int index = 2;
+
+  index += parseValue(data, index, &input_freq, sizeof(int));
+  index += parseValue(data, index, &output_freq, sizeof(int));
+  index += parseValue(data, index, &input_channels, sizeof(int));
+
+  index += parseValue(data, index, &left_volume, sizeof(float));
+  index += parseValue(data, index, &right_volume, sizeof(float));
+
+  if (!validFreq(input_freq) || !validFreq(output_freq)) {
+    // sampling frequencies must be reasonable
+    return 0;
+  }
+
+  if (input_channels < 1 ||
+      input_channels > (quality < AudioResampler::DYN_LOW_QUALITY ? 2 : 8)) {
+    // invalid number of input channels
+    return 0;
+  }
+
+  size_t single_channel_size =
+      format == AUDIO_FORMAT_PCM_FLOAT ? sizeof(float) : sizeof(int16_t);
+  size_t input_frame_size = single_channel_size * input_channels;
+  size_t input_size = size - metadata_size;
+  uint8_t input_data[input_size];
+  memcpy(input_data, &data[metadata_size], input_size);
+
+  size_t input_frames = input_size / input_frame_size;
+  if (input_frames > MAX_FRAMES) {
+    return 0;
+  }
+
+  Provider provider(input_data, input_frames, input_frame_size);
+
+  std::unique_ptr<AudioResampler> resampler(
+      AudioResampler::create(format, input_channels, output_freq, quality));
+
+  resampler->setSampleRate(input_freq);
+  resampler->setVolume(left_volume, right_volume);
+
+  // output is at least stereo samples
+  int output_channels = input_channels > 2 ? input_channels : 2;
+  size_t output_frame_size = output_channels * sizeof(int32_t);
+  size_t output_frames = (input_frames * output_freq) / input_freq;
+  size_t output_size = output_frames * output_frame_size;
+
+  uint8_t output_data[output_size];
+  for (size_t i = 0; i < output_frames; i++) {
+    memset(output_data, 0, output_size);
+    resampler->resample((int*)output_data, i, &provider);
+  }
+
+  return 0;
+}