Imported WebKit commit 2ea9d364d0f6efa8fa64acf19f451504c59be0e4 (http://svn.webkit.org/repository/webkit/trunk@104285)

1 files changed, 76 insertions, 0 deletions

diff --git a/Source/WebCore/webaudio/WaveShaperDSPKernel.cpp b/Source/WebCore/webaudio/WaveShaperDSPKernel.cpp
new file mode 100644
index 000000000..5f3cf3476
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+++ b/Source/WebCore/webaudio/WaveShaperDSPKernel.cpp
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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.
+ *
+ * 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 "WaveShaperDSPKernel.h"
+
+#include "WaveShaperProcessor.h"
+#include <algorithm>
+
+using namespace std;
+
+namespace WebCore {
+
+void WaveShaperDSPKernel::process(const float* source, float* destination, size_t framesToProcess)
+{
+    ASSERT(source && destination && waveShaperProcessor());
+
+    Float32Array* curve = waveShaperProcessor()->curve();
+    if (!curve) {
+        // Act as "straight wire" pass-through if no curve is set.
+        memcpy(destination, source, sizeof(float) * framesToProcess);
+        return;
+    }
+
+    float* curveData = curve->data();
+    int curveLength = curve->length();
+
+    ASSERT(curveData);
+
+    if (!curveData || !curveLength) {
+        memcpy(destination, source, sizeof(float) * framesToProcess);
+        return;
+    }
+
+    // Apply waveshaping curve.
+    for (unsigned i = 0; i < framesToProcess; ++i) {
+        const float input = source[i];
+
+        // Calculate an index based on input -1 -> +1 with 0 being at the center of the curve data.
+        int index = (curveLength * (input + 1)) / 2;
+
+        // Clip index to the input range of the curve.
+        // This takes care of input outside of nominal range -1 -> +1
+        index = max(index, 0);
+        index = min(index, curveLength - 1);
+        destination[i] = curveData[index];
+    }
+}
+
+} // namespace WebCore
+
+#endif // ENABLE(WEB_AUDIO)