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diff --git a/dom/media/webaudio/blink/DynamicsCompressor.h b/dom/media/webaudio/blink/DynamicsCompressor.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 DynamicsCompressor_h
+#define DynamicsCompressor_h
+
+#include "DynamicsCompressorKernel.h"
+#include "ZeroPole.h"
+
+#include "nsTArray.h"
+#include "nsAutoPtr.h"
+#include "mozilla/MemoryReporting.h"
+#include "mozilla/UniquePtr.h"
+
+namespace mozilla {
+class AudioBlock;
+} // namespace mozilla
+
+namespace WebCore {
+
+using mozilla::AudioBlock;
+
+// DynamicsCompressor implements a flexible audio dynamics compression effect such as
+// is commonly used in musical production and game audio. It lowers the volume
+// of the loudest parts of the signal and raises the volume of the softest parts,
+// making the sound richer, fuller, and more controlled.
+
+class DynamicsCompressor {
+public:
+    enum {
+        ParamThreshold,
+        ParamKnee,
+        ParamRatio,
+        ParamAttack,
+        ParamRelease,
+        ParamPreDelay,
+        ParamReleaseZone1,
+        ParamReleaseZone2,
+        ParamReleaseZone3,
+        ParamReleaseZone4,
+        ParamPostGain,
+        ParamFilterStageGain,
+        ParamFilterStageRatio,
+        ParamFilterAnchor,
+        ParamEffectBlend,
+        ParamReduction,
+        ParamLast
+    };
+
+    DynamicsCompressor(float sampleRate, unsigned numberOfChannels);
+
+    void process(const AudioBlock* sourceChunk, AudioBlock* destinationChunk, unsigned framesToProcess);
+    void reset();
+    void setNumberOfChannels(unsigned);
+    unsigned numberOfChannels() const { return m_numberOfChannels; }
+
+    void setParameterValue(unsigned parameterID, float value);
+    float parameterValue(unsigned parameterID);
+
+    float sampleRate() const { return m_sampleRate; }
+    float nyquist() const { return m_sampleRate / 2; }
+
+    double tailTime() const { return 0; }
+    double latencyTime() const { return m_compressor.latencyFrames() / static_cast<double>(sampleRate()); }
+
+    size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+protected:
+    unsigned m_numberOfChannels;
+
+    // m_parameters holds the tweakable compressor parameters.
+    float m_parameters[ParamLast];
+    void initializeParameters();
+
+    float m_sampleRate;
+
+    // Emphasis filter controls.
+    float m_lastFilterStageRatio;
+    float m_lastAnchor;
+    float m_lastFilterStageGain;
+
+    typedef struct {
+        ZeroPole filters[4];
+        size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
+        {
+            return aMallocSizeOf(this);
+        }
+    } ZeroPoleFilterPack4;
+
+    // Per-channel emphasis filters.
+    nsTArray<nsAutoPtr<ZeroPoleFilterPack4> > m_preFilterPacks;
+    nsTArray<nsAutoPtr<ZeroPoleFilterPack4> > m_postFilterPacks;
+
+    mozilla::UniquePtr<const float*[]> m_sourceChannels;
+    mozilla::UniquePtr<float*[]> m_destinationChannels;
+
+    void setEmphasisStageParameters(unsigned stageIndex, float gain, float normalizedFrequency /* 0 -> 1 */);
+    void setEmphasisParameters(float gain, float anchorFreq, float filterStageRatio);
+
+    // The core compressor.
+    DynamicsCompressorKernel m_compressor;
+};
+
+} // namespace WebCore
+
+#endif // DynamicsCompressor_h