import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

dom/media/webaudio/blink/FFTConvolver.h

@@ -0,0 +1,85 @@
+/*
+ * 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 FFTConvolver_h
+#define FFTConvolver_h
+
+#include "nsTArray.h"
+#include "mozilla/FFTBlock.h"
+#include "mozilla/MemoryReporting.h"
+
+namespace WebCore {
+
+typedef AlignedTArray<float> AlignedAudioFloatArray;
+using mozilla::FFTBlock;
+
+class FFTConvolver {
+public:
+    // |fftSize| must be a power of two.
+    //
+    // |renderPhase| is the initial offset in the initially zero input buffer.
+    // It is coordinated with the other stages, so they don't all do their
+    // FFTs at the same time.
+    explicit FFTConvolver(size_t fftSize, size_t renderPhase = 0);
+
+    // Process WEBAUDIO_BLOCK_SIZE elements of array |sourceP| and return a
+    // pointer to an output array of the same size.
+    //
+    // |fftKernel| must be pre-scaled for FFTBlock::GetInverseWithoutScaling().
+    //
+    // FIXME: Later, we can do more sophisticated buffering to relax this requirement...
+    const float* process(FFTBlock* fftKernel, const float* sourceP);
+
+    void reset();
+
+    size_t fftSize() const { return m_frame.FFTSize(); }
+
+    // The input to output latency is up to fftSize / 2, but alignment of the
+    // FFTs with the blocks reduces this by one block.
+    size_t latencyFrames() const;
+
+    size_t sizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+    size_t sizeOfIncludingThis(mozilla::MallocSizeOf aMallocSizeOf) const;
+
+private:
+    FFTBlock m_frame;
+
+    // Buffer input until we get fftSize / 2 samples then do an FFT
+    size_t m_readWriteIndex;
+    AlignedAudioFloatArray m_inputBuffer;
+
+    // Stores output which we read a little at a time
+    AlignedAudioFloatArray m_outputBuffer;
+
+    // Saves the 2nd half of the FFT buffer, so we can do an overlap-add with the 1st half of the next one
+    AlignedAudioFloatArray m_lastOverlapBuffer;
+};
+
+} // namespace WebCore
+
+#endif // FFTConvolver_h