/*

 * Copyright (C) 2011 Google Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1.  Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 * 2.  Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in the

 *     documentation and/or other materials provided with the distribution.

 * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of

 *     its contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE

 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY

 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES

 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;

 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND

 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF

 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#ifndef DynamicsCompressorKernel_h

#define DynamicsCompressorKernel_h

#include "nsTArray.h"

#include "mozilla/MemoryReporting.h"

#include "mozilla/UniquePtr.h"

namespace WebCore {

class DynamicsCompressorKernel {

public:

    DynamicsCompressorKernel(float sampleRate, unsigned numberOfChannels);

    void setNumberOfChannels(unsigned);

    // Performs stereo-linked compression.

    void process(float* sourceChannels[],

                 float* destinationChannels[],

                 unsigned numberOfChannels,

                 unsigned framesToProcess,

                 float dbThreshold,

                 float dbKnee,

                 float ratio,

                 float attackTime,

                 float releaseTime,

                 float preDelayTime,

                 float dbPostGain,

                 float effectBlend,

                 float releaseZone1,

                 float releaseZone2,

                 float releaseZone3,

                 float releaseZone4

                 );

    void reset();

    unsigned latencyFrames() const { return m_lastPreDelayFrames; }

    float sampleRate() const { return m_sampleRate; }

    float meteringGain() const { return m_meteringGain; }

    size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;

protected:

    float m_sampleRate;

    float m_detectorAverage;

    float m_compressorGain;

    // Metering

    float m_meteringReleaseK;

    float m_meteringGain;

    // Lookahead section.

    enum { MaxPreDelayFrames = 1024 };

    enum { MaxPreDelayFramesMask = MaxPreDelayFrames - 1 };

    enum { DefaultPreDelayFrames = 256 }; // setPreDelayTime() will override this initial value

    unsigned m_lastPreDelayFrames;

    void setPreDelayTime(float);

    nsTArray<mozilla::UniquePtr<float[]>> m_preDelayBuffers;

    int m_preDelayReadIndex;

    int m_preDelayWriteIndex;

    float m_maxAttackCompressionDiffDb;

    // Static compression curve.

    float kneeCurve(float x, float k);

    float saturate(float x, float k);

    float slopeAt(float x, float k);

    float kAtSlope(float desiredSlope);

    float updateStaticCurveParameters(float dbThreshold, float dbKnee, float ratio);

    // Amount of input change in dB required for 1 dB of output change.

    // This applies to the portion of the curve above m_kneeThresholdDb (see below).

    float m_ratio;

    float m_slope; // Inverse ratio.

    // The input to output change below the threshold is linear 1:1.

    float m_linearThreshold;

    float m_dbThreshold;

    // m_dbKnee is the number of dB above the threshold before we enter the "ratio" portion of the curve.

    // m_kneeThresholdDb = m_dbThreshold + m_dbKnee

    // The portion between m_dbThreshold and m_kneeThresholdDb is the "soft knee" portion of the curve

    // which transitions smoothly from the linear portion to the ratio portion.

    float m_dbKnee;

    float m_kneeThreshold;

    float m_kneeThresholdDb;

    float m_ykneeThresholdDb;

    // Internal parameter for the knee portion of the curve.

    float m_K;

};

} // namespace WebCore

#endif // DynamicsCompressorKernel_h