// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <stddef.h>
#include <stdint.h>

#include <limits>
#include <memory>

#include "base/macros.h"
#include "base/strings/stringprintf.h"
#include "base/time/time.h"
#include "build/build_config.h"
#include "media/base/audio_bus.h"
#include "media/base/audio_parameters.h"
#include "media/base/audio_sample_types.h"
#include "media/base/channel_layout.h"
#include "media/base/fake_audio_render_callback.h"
#include "testing/gtest/include/gtest/gtest.h"

namespace media {

static const int kChannels = 6;
static const ChannelLayout kChannelLayout = CHANNEL_LAYOUT_5_1;
// Use a buffer size which is intentionally not a multiple of kChannelAlignment.
static const int kFrameCount = media::AudioBus::kChannelAlignment * 32 - 1;
static const int kSampleRate = 48000;

class AudioBusTest : public testing::Test {
 public:
  AudioBusTest() {}
  ~AudioBusTest() override {
    for (size_t i = 0; i < data_.size(); ++i)
      base::AlignedFree(data_[i]);
  }

  void VerifyChannelAndFrameCount(AudioBus* bus) {
    EXPECT_EQ(kChannels, bus->channels());
    EXPECT_EQ(kFrameCount, bus->frames());
  }

  void VerifyArrayIsFilledWithValue(const float data[], int size, float value) {
    for (int i = 0; i < size; ++i)
      ASSERT_FLOAT_EQ(value, data[i]) << "i=" << i;
  }

  // Verify values for each channel in |result| are within |epsilon| of
  // |expected|.  If |epsilon| exactly equals 0, uses FLOAT_EQ macro.
  void VerifyAreEqualWithEpsilon(const AudioBus* result,
                                 const AudioBus* expected,
                                 float epsilon) {
    ASSERT_EQ(expected->channels(), result->channels());
    ASSERT_EQ(expected->frames(), result->frames());
    for (int ch = 0; ch < result->channels(); ++ch) {
      for (int i = 0; i < result->frames(); ++i) {
        SCOPED_TRACE(base::StringPrintf("ch=%d, i=%d", ch, i));

        if (epsilon == 0) {
          ASSERT_FLOAT_EQ(expected->channel(ch)[i], result->channel(ch)[i]);
        } else {
          ASSERT_NEAR(expected->channel(ch)[i], result->channel(ch)[i],
                      epsilon);
        }
      }
    }
  }

  // Verify values for each channel in |result| against |expected|.
  void VerifyAreEqual(const AudioBus* result, const AudioBus* expected) {
    VerifyAreEqualWithEpsilon(result, expected, 0);
  }

  // Read and write to the full extent of the allocated channel data.  Also test
  // the Zero() method and verify it does as advertised.  Also test data if data
  // is 16-byte aligned as advertised (see kChannelAlignment in audio_bus.h).
  void VerifyReadWriteAndAlignment(AudioBus* bus) {
    for (int i = 0; i < bus->channels(); ++i) {
      // Verify that the address returned by channel(i) is a multiple of
      // AudioBus::kChannelAlignment.
      ASSERT_EQ(0U, reinterpret_cast<uintptr_t>(
          bus->channel(i)) & (AudioBus::kChannelAlignment - 1));

      // Write into the channel buffer.
      std::fill(bus->channel(i), bus->channel(i) + bus->frames(), i);
    }

    for (int i = 0; i < bus->channels(); ++i)
      VerifyArrayIsFilledWithValue(bus->channel(i), bus->frames(), i);

    bus->Zero();
    for (int i = 0; i < bus->channels(); ++i)
      VerifyArrayIsFilledWithValue(bus->channel(i), bus->frames(), 0);
  }

  // Verify copying to and from |bus1| and |bus2|.
  void CopyTest(AudioBus* bus1, AudioBus* bus2) {
    // Fill |bus1| with dummy data.
    for (int i = 0; i < bus1->channels(); ++i)
      std::fill(bus1->channel(i), bus1->channel(i) + bus1->frames(), i);

    // Verify copy from |bus1| to |bus2|.
    bus2->Zero();
    bus1->CopyTo(bus2);
    VerifyAreEqual(bus1, bus2);

    // Verify copy from |bus2| to |bus1|.
    bus1->Zero();
    bus2->CopyTo(bus1);
    VerifyAreEqual(bus2, bus1);
  }

 protected:
  std::vector<float*> data_;

  DISALLOW_COPY_AND_ASSIGN(AudioBusTest);
};

// Verify basic Create(...) method works as advertised.
TEST_F(AudioBusTest, Create) {
  std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, kFrameCount);
  VerifyChannelAndFrameCount(bus.get());
  VerifyReadWriteAndAlignment(bus.get());
}

// Verify Create(...) using AudioParameters works as advertised.
TEST_F(AudioBusTest, CreateUsingAudioParameters) {
  std::unique_ptr<AudioBus> bus = AudioBus::Create(
      AudioParameters(AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout,
                      kSampleRate, 32, kFrameCount));
  VerifyChannelAndFrameCount(bus.get());
  VerifyReadWriteAndAlignment(bus.get());
}

// Verify an AudioBus created via wrapping a vector works as advertised.
TEST_F(AudioBusTest, WrapVector) {
  data_.reserve(kChannels);
  for (int i = 0; i < kChannels; ++i) {
    data_.push_back(static_cast<float*>(base::AlignedAlloc(
        sizeof(*data_[i]) * kFrameCount, AudioBus::kChannelAlignment)));
  }

  std::unique_ptr<AudioBus> bus = AudioBus::WrapVector(kFrameCount, data_);
  VerifyChannelAndFrameCount(bus.get());
  VerifyReadWriteAndAlignment(bus.get());
}

// Verify an AudioBus created via wrapping a memory block works as advertised.
TEST_F(AudioBusTest, WrapMemory) {
  AudioParameters params(
      AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout, kSampleRate, 32,
      kFrameCount);
  int data_size = AudioBus::CalculateMemorySize(params);
  std::unique_ptr<float, base::AlignedFreeDeleter> data(static_cast<float*>(
      base::AlignedAlloc(data_size, AudioBus::kChannelAlignment)));

  // Fill the memory with a test value we can check for after wrapping.
  static const float kTestValue = 3;
  std::fill(
      data.get(), data.get() + data_size / sizeof(*data.get()), kTestValue);

  std::unique_ptr<AudioBus> bus = AudioBus::WrapMemory(params, data.get());
  // Verify the test value we filled prior to wrapping.
  for (int i = 0; i < bus->channels(); ++i)
    VerifyArrayIsFilledWithValue(bus->channel(i), bus->frames(), kTestValue);
  VerifyChannelAndFrameCount(bus.get());
  VerifyReadWriteAndAlignment(bus.get());

  // Verify the channel vectors lie within the provided memory block.
  EXPECT_GE(bus->channel(0), data.get());
  EXPECT_LT(bus->channel(bus->channels() - 1) + bus->frames(),
            data.get() + data_size / sizeof(*data.get()));
}

// Simulate a shared memory transfer and verify results.
TEST_F(AudioBusTest, CopyTo) {
  // Create one bus with AudioParameters and the other through direct values to
  // test for parity between the Create() functions.
  AudioParameters params(
      AudioParameters::AUDIO_PCM_LINEAR, kChannelLayout, kSampleRate, 32,
      kFrameCount);
  std::unique_ptr<AudioBus> bus1 = AudioBus::Create(kChannels, kFrameCount);
  std::unique_ptr<AudioBus> bus2 = AudioBus::Create(params);

  {
    SCOPED_TRACE("Created");
    CopyTest(bus1.get(), bus2.get());
  }
  {
    SCOPED_TRACE("Wrapped Vector");
    // Try a copy to an AudioBus wrapping a vector.
    data_.reserve(kChannels);
    for (int i = 0; i < kChannels; ++i) {
      data_.push_back(static_cast<float*>(base::AlignedAlloc(
          sizeof(*data_[i]) * kFrameCount, AudioBus::kChannelAlignment)));
    }

    bus2 = AudioBus::WrapVector(kFrameCount, data_);
    CopyTest(bus1.get(), bus2.get());
  }
  {
    SCOPED_TRACE("Wrapped Memory");
    // Try a copy to an AudioBus wrapping a memory block.
    std::unique_ptr<float, base::AlignedFreeDeleter> data(static_cast<float*>(
        base::AlignedAlloc(AudioBus::CalculateMemorySize(params),
                           AudioBus::kChannelAlignment)));

    bus2 = AudioBus::WrapMemory(params, data.get());
    CopyTest(bus1.get(), bus2.get());
  }
}

// Verify Zero() and ZeroFrames(...) utility methods work as advertised.
TEST_F(AudioBusTest, Zero) {
  std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, kFrameCount);

  // Fill the bus with dummy data.
  for (int i = 0; i < bus->channels(); ++i)
    std::fill(bus->channel(i), bus->channel(i) + bus->frames(), i + 1);
  EXPECT_FALSE(bus->AreFramesZero());

  // Zero first half the frames of each channel.
  bus->ZeroFrames(kFrameCount / 2);
  for (int i = 0; i < bus->channels(); ++i) {
    SCOPED_TRACE("First Half Zero");
    VerifyArrayIsFilledWithValue(bus->channel(i), kFrameCount / 2, 0);
    VerifyArrayIsFilledWithValue(bus->channel(i) + kFrameCount / 2,
                                 kFrameCount - kFrameCount / 2, i + 1);
  }
  EXPECT_FALSE(bus->AreFramesZero());

  // Fill the bus with dummy data.
  for (int i = 0; i < bus->channels(); ++i)
    std::fill(bus->channel(i), bus->channel(i) + bus->frames(), i + 1);

  // Zero the last half of the frames.
  bus->ZeroFramesPartial(kFrameCount / 2, kFrameCount - kFrameCount / 2);
  for (int i = 0; i < bus->channels(); ++i) {
    SCOPED_TRACE("Last Half Zero");
    VerifyArrayIsFilledWithValue(bus->channel(i) + kFrameCount / 2,
                                 kFrameCount - kFrameCount / 2, 0);
    VerifyArrayIsFilledWithValue(bus->channel(i), kFrameCount / 2, i + 1);
  }
  EXPECT_FALSE(bus->AreFramesZero());

  // Fill the bus with dummy data.
  for (int i = 0; i < bus->channels(); ++i)
    std::fill(bus->channel(i), bus->channel(i) + bus->frames(), i + 1);

  // Zero all the frames of each channel.
  bus->Zero();
  for (int i = 0; i < bus->channels(); ++i) {
    SCOPED_TRACE("All Zero");
    VerifyArrayIsFilledWithValue(bus->channel(i), bus->frames(), 0);
  }
  EXPECT_TRUE(bus->AreFramesZero());
}

// Each test vector represents two channels of data in the following arbitrary
// layout: <min, zero, max, min, max / 2, min / 2, zero, max, zero, zero>.
static const int kTestVectorSize = 10;
static const uint8_t kTestVectorUint8[kTestVectorSize] = {
    0,         -INT8_MIN,          UINT8_MAX,
    0,         INT8_MAX / 2 + 128, INT8_MIN / 2 + 128,
    -INT8_MIN, UINT8_MAX,          -INT8_MIN,
    -INT8_MIN};
static const int16_t kTestVectorInt16[kTestVectorSize] = {
    INT16_MIN,     0, INT16_MAX, INT16_MIN, INT16_MAX / 2,
    INT16_MIN / 2, 0, INT16_MAX, 0,         0};
static const int32_t kTestVectorInt32[kTestVectorSize] = {
    INT32_MIN,     0, INT32_MAX, INT32_MIN, INT32_MAX / 2,
    INT32_MIN / 2, 0, INT32_MAX, 0,         0};
static const float kTestVectorFloat32[kTestVectorSize] = {
    -1.0f, 0.0f, 1.0f, -1.0f, 0.5f, -0.5f, 0.0f, 1.0f, 0.0f, 0.0f};

// Expected results.
static const int kTestVectorFrameCount = kTestVectorSize / 2;
static const float kTestVectorResult[][kTestVectorFrameCount] = {
    {-1.0f, 1.0f, 0.5f, 0.0f, 0.0f},
    {0.0f, -1.0f, -0.5f, 1.0f, 0.0f}};
static const int kTestVectorChannelCount = arraysize(kTestVectorResult);

// Verify FromInterleaved() deinterleaves audio in supported formats correctly.
TEST_F(AudioBusTest, FromInterleaved) {
  std::unique_ptr<AudioBus> bus =
      AudioBus::Create(kTestVectorChannelCount, kTestVectorFrameCount);
  std::unique_ptr<AudioBus> expected =
      AudioBus::Create(kTestVectorChannelCount, kTestVectorFrameCount);
  for (int ch = 0; ch < kTestVectorChannelCount; ++ch) {
    memcpy(expected->channel(ch), kTestVectorResult[ch],
           kTestVectorFrameCount * sizeof(*expected->channel(ch)));
  }

  // Test deprecated version that takes |bytes_per_sample| as an input.
  {
    SCOPED_TRACE("uint8_t");
    bus->Zero();
    bus->FromInterleaved(kTestVectorUint8, kTestVectorFrameCount,
                         sizeof(*kTestVectorUint8));

    // Biased uint8_t calculations have poor precision, so the epsilon here is
    // slightly more permissive than int16_t and int32_t calculations.
    VerifyAreEqualWithEpsilon(bus.get(), expected.get(),
                              1.0f / (std::numeric_limits<uint8_t>::max() - 1));
  }
  {
    SCOPED_TRACE("int16_t");
    bus->Zero();
    bus->FromInterleaved(kTestVectorInt16, kTestVectorFrameCount,
                         sizeof(*kTestVectorInt16));
    VerifyAreEqualWithEpsilon(
        bus.get(), expected.get(),
        1.0f / (std::numeric_limits<uint16_t>::max() + 1.0f));
  }
  {
    SCOPED_TRACE("int32_t");
    bus->Zero();
    bus->FromInterleaved(kTestVectorInt32, kTestVectorFrameCount,
                         sizeof(*kTestVectorInt32));

    VerifyAreEqualWithEpsilon(
        bus.get(), expected.get(),
        1.0f / (std::numeric_limits<uint32_t>::max() + 1.0f));
  }

  // Test non-deprecated version that takes SampleTypeTraits as a template
  // parameter.
  {
    SCOPED_TRACE("UnsignedInt8SampleTypeTraits");
    bus->Zero();
    bus->FromInterleaved<UnsignedInt8SampleTypeTraits>(kTestVectorUint8,
                                                       kTestVectorFrameCount);
    // Biased uint8_t calculations have poor precision, so the epsilon here is
    // slightly more permissive than int16_t and int32_t calculations.
    VerifyAreEqualWithEpsilon(bus.get(), expected.get(),
                              1.0f / (std::numeric_limits<uint8_t>::max() - 1));
  }
  {
    SCOPED_TRACE("SignedInt16SampleTypeTraits");
    bus->Zero();
    bus->FromInterleaved<SignedInt16SampleTypeTraits>(kTestVectorInt16,
                                                      kTestVectorFrameCount);
    VerifyAreEqualWithEpsilon(
        bus.get(), expected.get(),
        1.0f / (std::numeric_limits<uint16_t>::max() + 1.0f));
  }
  {
    SCOPED_TRACE("SignedInt32SampleTypeTraits");
    bus->Zero();
    bus->FromInterleaved<SignedInt32SampleTypeTraits>(kTestVectorInt32,
                                                      kTestVectorFrameCount);
    VerifyAreEqualWithEpsilon(
        bus.get(), expected.get(),
        1.0f / (std::numeric_limits<uint32_t>::max() + 1.0f));
  }
  {
    SCOPED_TRACE("Float32SampleTypeTraits");
    bus->Zero();
    bus->FromInterleaved<Float32SampleTypeTraits>(kTestVectorFloat32,
                                                  kTestVectorFrameCount);
    VerifyAreEqual(bus.get(), expected.get());
  }
}

// Verify FromInterleavedPartial() deinterleaves audio correctly.
TEST_F(AudioBusTest, FromInterleavedPartial) {
  // Only deinterleave the middle two frames in each channel.
  static const int kPartialStart = 1;
  static const int kPartialFrames = 2;
  ASSERT_LE(kPartialStart + kPartialFrames, kTestVectorFrameCount);

  std::unique_ptr<AudioBus> bus =
      AudioBus::Create(kTestVectorChannelCount, kTestVectorFrameCount);
  std::unique_ptr<AudioBus> expected =
      AudioBus::Create(kTestVectorChannelCount, kTestVectorFrameCount);
  expected->Zero();
  for (int ch = 0; ch < kTestVectorChannelCount; ++ch) {
    memcpy(expected->channel(ch) + kPartialStart,
           kTestVectorResult[ch] + kPartialStart,
           kPartialFrames * sizeof(*expected->channel(ch)));
  }

  // Test deprecated version that takes |bytes_per_sample| as an input.
  {
    SCOPED_TRACE("int32_t");
    bus->Zero();
    bus->FromInterleavedPartial(
        kTestVectorInt32 + kPartialStart * bus->channels(), kPartialStart,
        kPartialFrames, sizeof(*kTestVectorInt32));
    VerifyAreEqual(bus.get(), expected.get());
  }

  // Test non-deprecated version that takes SampleTypeTraits as a template
  // parameter.
  {
    SCOPED_TRACE("SignedInt32SampleTypeTraits");
    bus->Zero();
    bus->FromInterleavedPartial<SignedInt32SampleTypeTraits>(
        kTestVectorInt32 + kPartialStart * bus->channels(), kPartialStart,
        kPartialFrames);
    VerifyAreEqual(bus.get(), expected.get());
  }
}

// Verify ToInterleaved() interleaves audio in suported formats correctly.
TEST_F(AudioBusTest, ToInterleaved) {
  std::unique_ptr<AudioBus> bus =
      AudioBus::Create(kTestVectorChannelCount, kTestVectorFrameCount);
  // Fill the bus with our test vector.
  for (int ch = 0; ch < bus->channels(); ++ch) {
    memcpy(bus->channel(ch), kTestVectorResult[ch],
           kTestVectorFrameCount * sizeof(*bus->channel(ch)));
  }

  // Test deprecated version that takes |bytes_per_sample| as an input.
  {
    SCOPED_TRACE("uint8_t");
    uint8_t test_array[arraysize(kTestVectorUint8)];
    bus->ToInterleaved(bus->frames(), sizeof(*kTestVectorUint8), test_array);
    ASSERT_EQ(0,
              memcmp(test_array, kTestVectorUint8, sizeof(kTestVectorUint8)));
  }
  {
    SCOPED_TRACE("int16_t");
    int16_t test_array[arraysize(kTestVectorInt16)];
    bus->ToInterleaved(bus->frames(), sizeof(*kTestVectorInt16), test_array);
    ASSERT_EQ(0,
              memcmp(test_array, kTestVectorInt16, sizeof(kTestVectorInt16)));
  }
  {
    SCOPED_TRACE("int32_t");
    int32_t test_array[arraysize(kTestVectorInt32)];
    bus->ToInterleaved(bus->frames(), sizeof(*kTestVectorInt32), test_array);

    // Some compilers get better precision than others on the half-max test, so
    // let the test pass with an off by one check on the half-max.
    int32_t alternative_acceptable_result[arraysize(kTestVectorInt32)];
    memcpy(alternative_acceptable_result, kTestVectorInt32,
           sizeof(kTestVectorInt32));
    ASSERT_EQ(alternative_acceptable_result[4],
              std::numeric_limits<int32_t>::max() / 2);
    alternative_acceptable_result[4]++;

    ASSERT_TRUE(
        memcmp(test_array, kTestVectorInt32, sizeof(kTestVectorInt32)) == 0 ||
        memcmp(test_array, alternative_acceptable_result,
               sizeof(alternative_acceptable_result)) == 0);
  }

  // Test non-deprecated version that takes SampleTypeTraits as a template
  // parameter.
  {
    SCOPED_TRACE("UnsignedInt8SampleTypeTraits");
    uint8_t test_array[arraysize(kTestVectorUint8)];
    bus->ToInterleaved<UnsignedInt8SampleTypeTraits>(bus->frames(), test_array);
    ASSERT_EQ(0,
              memcmp(test_array, kTestVectorUint8, sizeof(kTestVectorUint8)));
  }
  {
    SCOPED_TRACE("SignedInt16SampleTypeTraits");
    int16_t test_array[arraysize(kTestVectorInt16)];
    bus->ToInterleaved<SignedInt16SampleTypeTraits>(bus->frames(), test_array);
    ASSERT_EQ(0,
              memcmp(test_array, kTestVectorInt16, sizeof(kTestVectorInt16)));
  }
  {
    SCOPED_TRACE("SignedInt32SampleTypeTraits");
    int32_t test_array[arraysize(kTestVectorInt32)];
    bus->ToInterleaved<SignedInt32SampleTypeTraits>(bus->frames(), test_array);

    // Some compilers get better precision than others on the half-max test, so
    // let the test pass with an off by one check on the half-max.
    int32_t alternative_acceptable_result[arraysize(kTestVectorInt32)];
    memcpy(alternative_acceptable_result, kTestVectorInt32,
           sizeof(kTestVectorInt32));
    ASSERT_EQ(alternative_acceptable_result[4],
              std::numeric_limits<int32_t>::max() / 2);
    alternative_acceptable_result[4]++;

    ASSERT_TRUE(
        memcmp(test_array, kTestVectorInt32, sizeof(kTestVectorInt32)) == 0 ||
        memcmp(test_array, alternative_acceptable_result,
               sizeof(alternative_acceptable_result)) == 0);
  }
  {
    SCOPED_TRACE("Float32SampleTypeTraits");
    float test_array[arraysize(kTestVectorFloat32)];
    bus->ToInterleaved<Float32SampleTypeTraits>(bus->frames(), test_array);
    ASSERT_EQ(
        0, memcmp(test_array, kTestVectorFloat32, sizeof(kTestVectorFloat32)));
  }
}

// Verify ToInterleavedPartial() interleaves audio correctly.
TEST_F(AudioBusTest, ToInterleavedPartial) {
  // Only interleave the middle two frames in each channel.
  static const int kPartialStart = 1;
  static const int kPartialFrames = 2;
  ASSERT_LE(kPartialStart + kPartialFrames, kTestVectorFrameCount);

  std::unique_ptr<AudioBus> expected =
      AudioBus::Create(kTestVectorChannelCount, kTestVectorFrameCount);
  for (int ch = 0; ch < kTestVectorChannelCount; ++ch) {
    memcpy(expected->channel(ch), kTestVectorResult[ch],
           kTestVectorFrameCount * sizeof(*expected->channel(ch)));
  }

  // Test deprecated version that takes |bytes_per_sample| as an input.
  {
    SCOPED_TRACE("int16_t");
    int16_t test_array[arraysize(kTestVectorInt16)];
    expected->ToInterleavedPartial(kPartialStart, kPartialFrames,
                                   sizeof(*kTestVectorInt16), test_array);
    ASSERT_EQ(0, memcmp(test_array, kTestVectorInt16 +
                                        kPartialStart * kTestVectorChannelCount,
                        kPartialFrames * sizeof(*kTestVectorInt16) *
                            kTestVectorChannelCount));
  }

  // Test non-deprecated version that takes SampleTypeTraits as a template
  // parameter.
  {
    SCOPED_TRACE("Float32SampleTypeTraits");
    float test_array[arraysize(kTestVectorFloat32)];
    expected->ToInterleavedPartial<Float32SampleTypeTraits>(
        kPartialStart, kPartialFrames, test_array);
    ASSERT_EQ(0, memcmp(test_array, kTestVectorFloat32 +
                                        kPartialStart * kTestVectorChannelCount,
                        kPartialFrames * sizeof(*kTestVectorFloat32) *
                            kTestVectorChannelCount));
  }
}

struct ZeroingOutTestData {
  static constexpr int kChannelCount = 2;
  static constexpr int kFrameCount = 10;
  static constexpr int kInterleavedFrameCount = 3;

  std::unique_ptr<AudioBus> bus_under_test;
  std::vector<float> interleaved_dummy_frames;

  ZeroingOutTestData() {
    // Create a bus and fill each channel with a test pattern of form
    // [1.0, 2.0, 3.0, ...]
    bus_under_test = AudioBus::Create(kChannelCount, kFrameCount);
    for (int ch = 0; ch < kChannelCount; ++ch) {
      auto* sample_array_for_current_channel = bus_under_test->channel(ch);
      for (int frame_index = 0; frame_index < kFrameCount; frame_index++) {
        sample_array_for_current_channel[frame_index] =
            static_cast<float>(frame_index + 1);
      }
    }

    // Create a vector containing dummy interleaved samples.
    static const float kDummySampleValue = 0.123f;
    interleaved_dummy_frames.resize(kChannelCount * kInterleavedFrameCount);
    std::fill(interleaved_dummy_frames.begin(), interleaved_dummy_frames.end(),
              kDummySampleValue);
  }
};

TEST_F(AudioBusTest, FromInterleavedZerosOutUntouchedFrames) {
  ZeroingOutTestData test_data;

  // Exercise
  test_data.bus_under_test->FromInterleaved<Float32SampleTypeTraits>(
      &test_data.interleaved_dummy_frames[0], test_data.kInterleavedFrameCount);

  // Verification
  for (int ch = 0; ch < test_data.kChannelCount; ++ch) {
    auto* sample_array_for_current_channel =
        test_data.bus_under_test->channel(ch);
    for (int frame_index = test_data.kInterleavedFrameCount;
         frame_index < test_data.kFrameCount; frame_index++) {
      ASSERT_EQ(0.0f, sample_array_for_current_channel[frame_index]);
    }
  }
}

TEST_F(AudioBusTest, FromInterleavedPartialDoesNotZeroOutUntouchedFrames) {
  {
    SCOPED_TRACE("Zero write offset");

    ZeroingOutTestData test_data;
    static const int kWriteOffsetInFrames = 0;

    // Exercise
    test_data.bus_under_test->FromInterleavedPartial<Float32SampleTypeTraits>(
        &test_data.interleaved_dummy_frames[0], kWriteOffsetInFrames,
        test_data.kInterleavedFrameCount);

    // Verification
    for (int ch = 0; ch < test_data.kChannelCount; ++ch) {
      auto* sample_array_for_current_channel =
          test_data.bus_under_test->channel(ch);
      for (int frame_index =
               test_data.kInterleavedFrameCount + kWriteOffsetInFrames;
           frame_index < test_data.kFrameCount; frame_index++) {
        ASSERT_EQ(frame_index + 1,
                  sample_array_for_current_channel[frame_index]);
      }
    }
  }
  {
    SCOPED_TRACE("Positive write offset");

    ZeroingOutTestData test_data;
    static const int kWriteOffsetInFrames = 2;

    // Exercise
    test_data.bus_under_test->FromInterleavedPartial<Float32SampleTypeTraits>(
        &test_data.interleaved_dummy_frames[0], kWriteOffsetInFrames,
        test_data.kInterleavedFrameCount);

    // Verification
    for (int ch = 0; ch < test_data.kChannelCount; ++ch) {
      auto* sample_array_for_current_channel =
          test_data.bus_under_test->channel(ch);
      // Check untouched frames before write offset
      for (int frame_index = 0; frame_index < kWriteOffsetInFrames;
           frame_index++) {
        ASSERT_EQ(frame_index + 1,
                  sample_array_for_current_channel[frame_index]);
      }
      // Check untouched frames after write
      for (int frame_index =
               test_data.kInterleavedFrameCount + kWriteOffsetInFrames;
           frame_index < test_data.kFrameCount; frame_index++) {
        ASSERT_EQ(frame_index + 1,
                  sample_array_for_current_channel[frame_index]);
      }
    }
  }
}

TEST_F(AudioBusTest, Scale) {
  std::unique_ptr<AudioBus> bus = AudioBus::Create(kChannels, kFrameCount);

  // Fill the bus with dummy data.
  static const float kFillValue = 1;
  for (int i = 0; i < bus->channels(); ++i)
    std::fill(bus->channel(i), bus->channel(i) + bus->frames(), kFillValue);

  // Adjust by an invalid volume and ensure volume is unchanged.
  bus->Scale(-1);
  for (int i = 0; i < bus->channels(); ++i) {
    SCOPED_TRACE("Invalid Scale");
    VerifyArrayIsFilledWithValue(bus->channel(i), bus->frames(), kFillValue);
  }

  // Verify correct volume adjustment.
  static const float kVolume = 0.5;
  bus->Scale(kVolume);
  for (int i = 0; i < bus->channels(); ++i) {
    SCOPED_TRACE("Half Scale");
    VerifyArrayIsFilledWithValue(bus->channel(i), bus->frames(),
                                 kFillValue * kVolume);
  }

  // Verify zero volume case.
  bus->Scale(0);
  for (int i = 0; i < bus->channels(); ++i) {
    SCOPED_TRACE("Zero Scale");
    VerifyArrayIsFilledWithValue(bus->channel(i), bus->frames(), 0);
  }
}

}  // namespace media