Merge WebKit at r75315: Initial merge by git.

Change-Id: I570314b346ce101c935ed22a626b48c2af266b84

1 files changed, 141 insertions, 0 deletions

diff --git a/Source/WebCore/platform/audio/AudioBus.h b/Source/WebCore/platform/audio/AudioBus.h
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+++ b/Source/WebCore/platform/audio/AudioBus.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 AudioBus_h
+#define AudioBus_h
+
+#include "AudioChannel.h"
+#include <wtf/Noncopyable.h>
+#include <wtf/PassOwnPtr.h>
+#include <wtf/Vector.h>
+
+namespace WebCore {
+
+// An AudioBus represents a collection of one or more AudioChannels.
+// The data layout is "planar" as opposed to "interleaved".
+// An AudioBus with one channel is mono, an AudioBus with two channels is stereo, etc.
+class AudioBus  : public Noncopyable {
+public:
+    enum {
+        ChannelLeft = 0,
+        ChannelRight = 1,
+        ChannelCenter = 2, // center and mono are the same
+        ChannelMono = 2,
+        ChannelLFE = 3,
+        ChannelSurroundLeft = 4,
+        ChannelSurroundRight = 5,
+    };
+
+    enum {
+        LayoutCanonical = 0
+        // Can define non-standard layouts here
+    };
+
+    // allocate indicates whether or not to initially have the AudioChannels created with managed storage.
+    // Normal usage is to pass true here, in which case the AudioChannels will memory-manage their own storage.
+    // If allocate is false then setChannelMemory() has to be called later on for each channel before the AudioBus is useable...
+    AudioBus(unsigned numberOfChannels, size_t length, bool allocate = true);
+
+    // Tells the given channel to use an externally allocated buffer.
+    void setChannelMemory(unsigned channelIndex, float* storage, size_t length);
+
+    // Channels
+    unsigned numberOfChannels() const { return m_channels.size(); }
+
+    AudioChannel* channel(unsigned channel) { return m_channels[channel].get(); }
+    const AudioChannel* channel(unsigned channel) const { return const_cast<AudioBus*>(this)->m_channels[channel].get(); }
+    AudioChannel* channelByType(unsigned type);
+
+    // Number of sample-frames
+    size_t length() const { return m_length; }
+
+    // Sample-rate : 0.0 if unknown or "don't care"
+    double sampleRate() const { return m_sampleRate; }
+    void setSampleRate(double sampleRate) { m_sampleRate = sampleRate; }
+
+    // Zeroes all channels.
+    void zero();
+
+    // Returns true if the channel count and frame-size match.
+    bool topologyMatches(const AudioBus &sourceBus) const;
+
+    // Creates a new buffer from a range in the source buffer.
+    // 0 may be returned if the range does not fit in the sourceBuffer
+    static PassOwnPtr<AudioBus> createBufferFromRange(AudioBus* sourceBuffer, unsigned startFrame, unsigned endFrame);
+
+    // Scales all samples by the same amount.
+    void scale(double scale);
+
+    // Master gain for this bus - used with sumWithGainFrom() below
+    void setGain(double gain) { m_busGain = gain; }
+    double gain() { return m_busGain; }
+
+    void reset() { m_isFirstTime = true; } // for de-zippering
+
+    // Assuming sourceBus has the same topology, copies sample data from each channel of sourceBus to our corresponding channel.
+    void copyFrom(const AudioBus &sourceBus);
+
+    // Sums the sourceBus into our bus with unity gain.
+    // Our own internal gain m_busGain is ignored.
+    void sumFrom(const AudioBus &sourceBus);
+
+    // Copy or sum each channel from sourceBus into our corresponding channel.
+    // We scale by targetGain (and our own internal gain m_busGain), performing "de-zippering" to smoothly change from *lastMixGain to (targetGain*m_busGain).
+    // The caller is responsible for setting up lastMixGain to point to storage which is unique for every "stream" which will be summed to this bus.
+    // This represents the dezippering memory.
+    void copyWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain);
+    void sumWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain);
+
+    // Returns maximum absolute value across all channels (useful for normalization).
+    float maxAbsValue() const;
+
+    // Makes maximum absolute value == 1.0 (if possible).
+    void normalize();
+
+    static PassOwnPtr<AudioBus> loadPlatformResource(const char* name, double sampleRate);
+
+protected:
+    AudioBus() { };
+
+    void processWithGainFrom(const AudioBus &sourceBus, double* lastMixGain, double targetGain, bool sumToBus);
+    void processWithGainFromMonoStereo(const AudioBus &sourceBus, double* lastMixGain, double targetGain, bool sumToBus);
+
+    size_t m_length;
+
+    Vector<OwnPtr<AudioChannel> > m_channels;
+
+    int m_layout;
+
+    double m_busGain;
+    bool m_isFirstTime;
+    double m_sampleRate; // 0.0 if unknown or N/A
+};
+
+} // WebCore
+
+#endif // AudioBus_h