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diff --git a/Source/WebCore/platform/audio/Distance.h b/Source/WebCore/platform/audio/Distance.h
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+/*
+ * Copyright (C) 2010 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 Distance_h
+#define Distance_h
+
+namespace WebCore {
+
+// Distance models are defined according to the OpenAL specification
+
+class DistanceEffect {
+public:
+    enum ModelType {
+        ModelLinear = 0,
+        ModelInverse = 1,
+        ModelExponential = 2
+    };
+
+    DistanceEffect();
+
+    // Returns scalar gain for the given distance the current distance model is used
+    double gain(double distance);
+
+    ModelType model() { return m_model; }
+
+    void setModel(ModelType model, bool clamped)
+    {
+        m_model = model;
+        m_isClamped = clamped;
+    }
+
+    // Distance params
+    void setRefDistance(double refDistance) { m_refDistance = refDistance; }
+    void setMaxDistance(double maxDistance) { m_maxDistance = maxDistance; }
+    void setRolloffFactor(double rolloffFactor) { m_rolloffFactor = rolloffFactor; }
+
+    double refDistance() const { return m_refDistance; }
+    double maxDistance() const { return m_maxDistance; }
+    double rolloffFactor() const { return m_rolloffFactor; }
+
+protected:
+    double linearGain(double distance);
+    double inverseGain(double distance);
+    double exponentialGain(double distance);
+
+    ModelType m_model;
+    bool m_isClamped;
+    double m_refDistance;
+    double m_maxDistance;
+    double m_rolloffFactor;
+};
+
+} // namespace WebCore
+
+#endif // Distance_h