зеркало из https://github.com/mozilla/gecko-dev.git
69 строки
2.5 KiB
C++
69 строки
2.5 KiB
C++
/*
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* Copyright (C) 2011 Google Inc. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of
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* its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
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* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "ZeroPole.h"
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#include "DenormalDisabler.h"
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namespace WebCore {
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void ZeroPole::process(const float *source, float *destination, unsigned framesToProcess)
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{
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float zero = m_zero;
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float pole = m_pole;
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// Gain compensation to make 0dB @ 0Hz
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const float k1 = 1 / (1 - zero);
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const float k2 = 1 - pole;
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// Member variables to locals.
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float lastX = m_lastX;
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float lastY = m_lastY;
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while (framesToProcess--) {
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float input = *source++;
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// Zero
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float output1 = k1 * (input - zero * lastX);
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lastX = input;
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// Pole
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float output2 = k2 * output1 + pole * lastY;
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lastY = output2;
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*destination++ = output2;
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}
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// Locals to member variables. Flush denormals here so we don't
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// slow down the inner loop above.
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m_lastX = DenormalDisabler::flushDenormalFloatToZero(lastX);
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m_lastY = DenormalDisabler::flushDenormalFloatToZero(lastY);
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}
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} // namespace WebCore
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