third_party/WebKit/Source/platform/audio/AudioDSPKernelProcessor.cpp

/*
 * Copyright (C) 2010 Google Inc. All rights reserved.
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 * modification, are permitted provided that the following conditions are
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#include "platform/audio/AudioDSPKernelProcessor.h"
#include "platform/audio/AudioDSPKernel.h"

namespace blink {

// setNumberOfChannels() may later be called if the object is not yet in an
// "initialized" state.
AudioDSPKernelProcessor::AudioDSPKernelProcessor(float sampleRate,
                                                 unsigned numberOfChannels)
    : AudioProcessor(sampleRate, numberOfChannels), m_hasJustReset(true) {}

void AudioDSPKernelProcessor::initialize() {
  if (isInitialized())
    return;

  MutexLocker locker(m_processLock);
  ASSERT(!m_kernels.size());

  // Create processing kernels, one per channel.
  for (unsigned i = 0; i < numberOfChannels(); ++i)
    m_kernels.append(createKernel());

  m_initialized = true;
  m_hasJustReset = true;
}

void AudioDSPKernelProcessor::uninitialize() {
  if (!isInitialized())
    return;

  MutexLocker locker(m_processLock);
  m_kernels.clear();

  m_initialized = false;
}

void AudioDSPKernelProcessor::process(const AudioBus* source,
                                      AudioBus* destination,
                                      size_t framesToProcess) {
  ASSERT(source && destination);
  if (!source || !destination)
    return;

  if (!isInitialized()) {
    destination->zero();
    return;
  }

  MutexTryLocker tryLocker(m_processLock);
  if (tryLocker.locked()) {
    bool channelCountMatches =
        source->numberOfChannels() == destination->numberOfChannels() &&
        source->numberOfChannels() == m_kernels.size();
    ASSERT(channelCountMatches);
    if (!channelCountMatches)
      return;

    for (unsigned i = 0; i < m_kernels.size(); ++i)
      m_kernels[i]->process(source->channel(i)->data(),
                            destination->channel(i)->mutableData(),
                            framesToProcess);
  } else {
    // Unfortunately, the kernel is being processed by another thread.
    // See also ConvolverNode::process().
    destination->zero();
  }
}

// Resets filter state
void AudioDSPKernelProcessor::reset() {
  ASSERT(isMainThread());
  if (!isInitialized())
    return;

  // Forces snap to parameter values - first time.
  // Any processing depending on this value must set it to false at the
  // appropriate time.
  m_hasJustReset = true;

  MutexLocker locker(m_processLock);
  for (unsigned i = 0; i < m_kernels.size(); ++i)
    m_kernels[i]->reset();
}

void AudioDSPKernelProcessor::setNumberOfChannels(unsigned numberOfChannels) {
  if (numberOfChannels == m_numberOfChannels)
    return;

  ASSERT(!isInitialized());
  if (!isInitialized())
    m_numberOfChannels = numberOfChannels;
}

double AudioDSPKernelProcessor::tailTime() const {
  ASSERT(!isMainThread());
  MutexTryLocker tryLocker(m_processLock);
  if (tryLocker.locked()) {
    // It is expected that all the kernels have the same tailTime.
    return !m_kernels.isEmpty() ? m_kernels.first()->tailTime() : 0;
  }
  // Since we don't want to block the Audio Device thread, we return a large
  // value instead of trying to acquire the lock.
  return std::numeric_limits<double>::infinity();
}

double AudioDSPKernelProcessor::latencyTime() const {
  ASSERT(!isMainThread());
  MutexTryLocker tryLocker(m_processLock);
  if (tryLocker.locked()) {
    // It is expected that all the kernels have the same latencyTime.
    return !m_kernels.isEmpty() ? m_kernels.first()->latencyTime() : 0;
  }
  // Since we don't want to block the Audio Device thread, we return a large
  // value instead of trying to acquire the lock.
  return std::numeric_limits<double>::infinity();
}

}  // namespace blink