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diff --git a/dom/media/webaudio/blink/DynamicsCompressorKernel.h b/dom/media/webaudio/blink/DynamicsCompressorKernel.h
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+/*
+ * 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