Merge WebKit at r70209: Initial merge by Git

Change-Id: Id23a68efa36e9d1126bcce0b137872db00892c8e

1 files changed, 140 insertions, 0 deletions

diff --git a/WebCore/webaudio/DelayDSPKernel.cpp b/WebCore/webaudio/DelayDSPKernel.cpp
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+++ b/WebCore/webaudio/DelayDSPKernel.cpp
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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.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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.
+ */
+
+#include "config.h"
+
+#if ENABLE(WEB_AUDIO)
+
+#include "DelayDSPKernel.h"
+
+#include "AudioUtilities.h"
+#include <algorithm>
+
+using namespace std;
+  
+const double DefaultMaxDelayTime = 1.0;
+const double SmoothingTimeConstant = 0.020; // 20ms
+  
+namespace WebCore {
+
+DelayDSPKernel::DelayDSPKernel(DelayProcessor* processor)
+    : AudioDSPKernel(processor)
+    , m_maxDelayTime(DefaultMaxDelayTime)
+    , m_writeIndex(0)
+    , m_firstTime(true)
+{
+    ASSERT(processor && processor->sampleRate() > 0);
+    if (!processor)
+        return;
+
+    m_buffer.resize(static_cast<size_t>(processor->sampleRate() * DefaultMaxDelayTime));
+    m_buffer.zero();
+
+    m_smoothingRate = AudioUtilities::discreteTimeConstantForSampleRate(SmoothingTimeConstant, processor->sampleRate());
+}
+
+DelayDSPKernel::DelayDSPKernel(double maxDelayTime, double sampleRate)
+    : AudioDSPKernel(sampleRate)
+    , m_maxDelayTime(maxDelayTime)
+    , m_writeIndex(0)
+    , m_firstTime(true)
+{
+    ASSERT(maxDelayTime > 0.0);
+    if (maxDelayTime <= 0.0)
+        return;
+        
+    size_t bufferLength = static_cast<size_t>(sampleRate * maxDelayTime);
+    ASSERT(bufferLength);
+    if (!bufferLength)
+        return;
+    
+    m_buffer.resize(bufferLength);
+    m_buffer.zero();
+
+    m_smoothingRate = AudioUtilities::discreteTimeConstantForSampleRate(SmoothingTimeConstant, sampleRate);
+}
+
+void DelayDSPKernel::process(const float* source, float* destination, size_t framesToProcess)
+{
+    size_t bufferLength = m_buffer.size();
+    float* buffer = m_buffer.data();
+
+    ASSERT(bufferLength);
+    if (!bufferLength)
+        return;
+        
+    ASSERT(source && destination);
+    if (!source || !destination)
+        return;
+        
+    double sampleRate = this->sampleRate();
+    double delayTime = delayProcessor() ? delayProcessor()->delayTime()->value() : m_desiredDelayFrames / sampleRate;
+
+    // Make sure the delay time is in a valid range.
+    delayTime = min(maxDelayTime(), delayTime);
+    delayTime = max(0.0, delayTime);
+
+    if (m_firstTime) {
+        m_currentDelayTime = delayTime;
+        m_firstTime = false;
+    }
+    
+    int n = framesToProcess;
+    while (n--) {
+        // Approach desired delay time.
+        m_currentDelayTime += (delayTime - m_currentDelayTime) * m_smoothingRate;
+
+        double desiredDelayFrames = m_currentDelayTime * sampleRate;
+
+        double readPosition = m_writeIndex + bufferLength - desiredDelayFrames;
+        if (readPosition > bufferLength)
+            readPosition -= bufferLength;
+
+        // Linearly interpolate in-between delay times.
+        int readIndex1 = static_cast<int>(readPosition);
+        int readIndex2 = (readIndex1 + 1) % bufferLength;
+        double interpolationFactor = readPosition - readIndex1;
+
+        double input = static_cast<float>(*source++);
+        buffer[m_writeIndex] = static_cast<float>(input);
+        m_writeIndex = (m_writeIndex + 1) % bufferLength;        
+        
+        double sample1 = buffer[readIndex1];
+        double sample2 = buffer[readIndex2];
+        
+        double output = (1.0 - interpolationFactor) * sample1 + interpolationFactor * sample2;
+
+        *destination++ = static_cast<float>(output);
+    }        
+}
+
+void DelayDSPKernel::reset()
+{
+    m_firstTime = true;
+    m_buffer.zero();
+}
+
+} // namespace WebCore
+
+#endif // ENABLE(WEB_AUDIO)