1 files changed, 180 insertions, 23 deletions

diff --git a/media/base/audio_bus.cc b/media/base/audio_bus.cc
index 4c43af7..a7d9ad0 100644
--- a/media/base/audio_bus.cc
+++ b/media/base/audio_bus.cc
@@ -12,40 +12,116 @@
 
 namespace media {
 
-// Ensure each channel is 16-byte aligned for easy SSE optimizations.
-static const int kChannelAlignment = 16;
-
 static bool IsAligned(void* ptr) {
-  return (reinterpret_cast<uintptr_t>(ptr) & (kChannelAlignment - 1)) == 0U;
+  return (reinterpret_cast<uintptr_t>(ptr) &
+          (AudioBus::kChannelAlignment - 1)) == 0U;
 }
 
-AudioBus::AudioBus(int channels, int frames)
-    : frames_(frames) {
+// Calculates the required size for an AudioBus with the given params, sets
+// |aligned_frames| to the actual frame length of each channel array.
+static int CalculateMemorySizeInternal(int channels, int frames,
+                                       int* aligned_frames) {
+  CHECK(aligned_frames);
+  // Choose a size such that each channel will be aligned by kChannelAlignment
+  // when stored in a contiguous block.
+  *aligned_frames =
+      ((frames * sizeof(float) + AudioBus::kChannelAlignment - 1) &
+       ~(AudioBus::kChannelAlignment - 1)) / sizeof(float);
+  return sizeof(float) * channels * (*aligned_frames);
+}
+
+// |Format| is the destination type, |Fixed| is a type larger than |Format|
+// such that operations can be made without overflowing.
+template<class Format, class Fixed>
+static void FromInterleavedInternal(const void* src, int frames,
+                                    AudioBus* dest) {
+  const Format* source = static_cast<const Format*>(src);
+
+  static const Fixed kBias = std::numeric_limits<Format>::is_signed ? 0 :
+      std::numeric_limits<Format>::max() / 2 + 1;
+  static const float kMaxScale = 1.0f / (kBias ? kBias - 1 :
+      std::numeric_limits<Format>::max());
+  static const float kMinScale = 1.0f / (kBias ? kBias :
+      -static_cast<Fixed>(std::numeric_limits<Format>::min()));
+
+  int channels = dest->channels();
+  for (int ch = 0; ch < channels; ++ch) {
+    float* channel_data = dest->channel(ch);
+    for (int i = 0, offset = ch; i < frames; ++i, offset += channels) {
+      Fixed v = static_cast<Fixed>(source[offset]) - kBias;
+      channel_data[i] = v * (v < 0 ? kMinScale : kMaxScale);
+    }
+  }
+}
+
+// |Format| is the destination type, |Fixed| is a type larger than |Format|
+// such that operations can be made without overflowing.
+template<class Format, class Fixed>
+static void ToInterleavedInternal(const AudioBus* source, int frames,
+                                  void* dst) {
+  Format* dest = static_cast<Format*>(dst);
+
+  static const Format kBias = std::numeric_limits<Format>::is_signed ? 0 :
+      std::numeric_limits<Format>::max() / 2 + 1;
+  static const Fixed kMaxValue = kBias ? kBias - 1 :
+      std::numeric_limits<Format>::max();
+  static const Fixed kMinValue = kBias ? -kBias :
+      std::numeric_limits<Format>::min();
+
+  int channels = source->channels();
+  for (int ch = 0; ch < channels; ++ch) {
+    const float* channel_data = source->channel(ch);
+    for (int i = 0, offset = ch; i < frames; ++i, offset += channels) {
+      float v = channel_data[i];
+      Fixed sample = v * (v < 0 ? -kMinValue : kMaxValue);
+
+      if (sample > kMaxValue)
+        sample = kMaxValue;
+      else if (sample < kMinValue)
+        sample = kMinValue;
+
+      dest[offset] = static_cast<Format>(sample) + kBias;
+    }
+  }
+}
+
+static void ValidateConfig(int channels, int frames) {
   CHECK_GT(frames, 0);
   CHECK_LE(frames, limits::kMaxSamplesPerPacket);
   CHECK_GT(channels, 0);
   CHECK_LE(channels, limits::kMaxChannels);
   DCHECK_LT(limits::kMaxSamplesPerPacket * limits::kMaxChannels,
             std::numeric_limits<int>::max());
+}
 
-  // Choose a size such that each channel is aligned by kChannelAlignment.
-  int aligned_frames =
-      (frames_ + kChannelAlignment - 1) & ~(kChannelAlignment - 1);
-  data_size_ = sizeof(float) * channels * aligned_frames;
+AudioBus::AudioBus(int channels, int frames)
+    : frames_(frames) {
+  ValidateConfig(channels, frames_);
+
+  int aligned_frames = 0;
+  int size = CalculateMemorySizeInternal(channels, frames, &aligned_frames);
 
   data_.reset(static_cast<float*>(base::AlignedAlloc(
-      data_size_, kChannelAlignment)));
+      size, AudioBus::kChannelAlignment)));
 
-  // Separate audio data out into channels for easy lookup later.
-  channel_data_.reserve(channels);
-  for (int i = 0; i < channels; ++i)
-    channel_data_.push_back(data_.get() + i * aligned_frames);
+  BuildChannelData(channels, aligned_frames, data_.get());
+}
+
+AudioBus::AudioBus(int channels, int frames, float* data)
+    : frames_(frames) {
+  ValidateConfig(channels, frames_);
+
+  int aligned_frames = 0;
+  CalculateMemorySizeInternal(channels, frames, &aligned_frames);
+
+  BuildChannelData(channels, aligned_frames, data);
 }
 
 AudioBus::AudioBus(int frames, const std::vector<float*>& channel_data)
-    : data_size_(0),
-      channel_data_(channel_data),
+    : channel_data_(channel_data),
       frames_(frames) {
+  ValidateConfig(channel_data_.size(), frames_);
+
   // Sanity check wrapped vector for alignment and channel count.
   for (size_t i = 0; i < channel_data_.size(); ++i)
     DCHECK(IsAligned(channel_data_[i]));
@@ -67,14 +143,21 @@ scoped_ptr<AudioBus> AudioBus::WrapVector(
   return scoped_ptr<AudioBus>(new AudioBus(frames, channel_data));
 }
 
-void* AudioBus::data() {
-  DCHECK(data_.get());
-  return data_.get();
+scoped_ptr<AudioBus> AudioBus::WrapMemory(int channels, int frames,
+                                          void* data) {
+  // |data| must be aligned by AudioBus::kChannelAlignment.
+  CHECK(IsAligned(data));
+  return scoped_ptr<AudioBus>(new AudioBus(
+      channels, frames, static_cast<float*>(data)));
 }
 
-int AudioBus::data_size() const {
-  DCHECK(data_.get());
-  return data_size_;
+scoped_ptr<AudioBus> AudioBus::WrapMemory(const AudioParameters& params,
+                                          void* data) {
+  // |data| must be aligned by AudioBus::kChannelAlignment.
+  CHECK(IsAligned(data));
+  return scoped_ptr<AudioBus>(new AudioBus(
+      params.channels(), params.frames_per_buffer(),
+      static_cast<float*>(data)));
 }
 
 void AudioBus::ZeroFrames(int frames) {
@@ -87,4 +170,78 @@ void AudioBus::Zero() {
   ZeroFrames(frames_);
 }
 
+int AudioBus::CalculateMemorySize(const AudioParameters& params) {
+  int aligned_frames = 0;
+  return CalculateMemorySizeInternal(
+      params.channels(), params.frames_per_buffer(), &aligned_frames);
+}
+
+void AudioBus::BuildChannelData(int channels, int aligned_frames, float* data) {
+  DCHECK(IsAligned(data));
+  DCHECK_EQ(channel_data_.size(), 0U);
+  // Separate audio data out into channels for easy lookup later.  Figure out
+  channel_data_.reserve(channels);
+  for (int i = 0; i < channels; ++i)
+    channel_data_.push_back(data + i * aligned_frames);
+}
+
+// TODO(dalecurtis): See if intrinsic optimizations help any here.
+void AudioBus::FromInterleaved(const void* source, int frames,
+                               int bytes_per_sample) {
+  DCHECK_LE(frames, frames_);
+  switch (bytes_per_sample) {
+    case 1:
+      FromInterleavedInternal<uint8, int16>(source, frames, this);
+      break;
+    case 2:
+      FromInterleavedInternal<int16, int32>(source, frames, this);
+      break;
+    case 4:
+      FromInterleavedInternal<int32, int64>(source, frames, this);
+      break;
+    default:
+      NOTREACHED() << "Unsupported bytes per sample encountered.";
+      Zero();
+      return;
+  }
+
+  // Zero any remaining frames.
+  int remaining_frames = (frames_ - frames);
+  if (remaining_frames) {
+    for (int ch = 0; ch < channels(); ++ch)
+      memset(channel(ch) + frames, 0, sizeof(*channel(ch)) * remaining_frames);
+  }
+}
+
+// TODO(dalecurtis): See if intrinsic optimizations help any here.
+void AudioBus::ToInterleaved(int frames, int bytes_per_sample,
+                             void* dest) const {
+  DCHECK_LE(frames, frames_);
+  switch (bytes_per_sample) {
+    case 1:
+      ToInterleavedInternal<uint8, int16>(this, frames, dest);
+      break;
+    case 2:
+      ToInterleavedInternal<int16, int32>(this, frames, dest);
+      break;
+    case 4:
+      ToInterleavedInternal<int32, int64>(this, frames, dest);
+      break;
+    default:
+      NOTREACHED() << "Unsupported bytes per sample encountered.";
+      memset(dest, 0, frames * bytes_per_sample);
+      return;
+  }
+}
+
+void AudioBus::CopyTo(AudioBus* dest) const {
+  DCHECK_EQ(channels(), dest->channels());
+  DCHECK_EQ(frames(), dest->frames());
+
+  // Since we don't know if the other AudioBus is wrapped or not (and we don't
+  // want to care), just copy using the public channel() accessors.
+  for (int i = 0; i < channels(); ++i)
+    memcpy(dest->channel(i), channel(i), sizeof(*channel(i)) * frames());
+}
+
 }  // namespace media