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author | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
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committer | Matt A. Tobin <mattatobin@localhost.localdomain> | 2018-02-02 04:16:08 -0500 |
commit | 5f8de423f190bbb79a62f804151bc24824fa32d8 (patch) | |
tree | 10027f336435511475e392454359edea8e25895d /dom/media/webaudio/blink/ZeroPole.cpp | |
parent | 49ee0794b5d912db1f95dce6eb52d781dc210db5 (diff) | |
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Add m-esr52 at 52.6.0
Diffstat (limited to 'dom/media/webaudio/blink/ZeroPole.cpp')
-rw-r--r-- | dom/media/webaudio/blink/ZeroPole.cpp | 78 |
1 files changed, 78 insertions, 0 deletions
diff --git a/dom/media/webaudio/blink/ZeroPole.cpp b/dom/media/webaudio/blink/ZeroPole.cpp new file mode 100644 index 000000000..ac0b15c7a --- /dev/null +++ b/dom/media/webaudio/blink/ZeroPole.cpp @@ -0,0 +1,78 @@ +/* + * 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. + * 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. + */ + +#include "ZeroPole.h" + +#include <cmath> +#include <float.h> + +namespace WebCore { + +void ZeroPole::process(const float *source, float *destination, int framesToProcess) +{ + float zero = m_zero; + float pole = m_pole; + + // Gain compensation to make 0dB @ 0Hz + const float k1 = 1 / (1 - zero); + const float k2 = 1 - pole; + + // Member variables to locals. + float lastX = m_lastX; + float lastY = m_lastY; + + for (int i = 0; i < framesToProcess; ++i) { + float input = source[i]; + + // Zero + float output1 = k1 * (input - zero * lastX); + lastX = input; + + // Pole + float output2 = k2 * output1 + pole * lastY; + lastY = output2; + + destination[i] = output2; + } + + // Locals to member variables. Flush denormals here so we don't + // slow down the inner loop above. + if (lastX == 0.0f && lastY != 0.0f && fabsf(lastY) < FLT_MIN) { + // Flush future values to zero (until there is new input). + lastY = 0.0; + // Flush calculated values. + for (int i = framesToProcess; i-- && fabsf(destination[i]) < FLT_MIN; ) { + destination[i] = 0.0f; + } + } + + m_lastX = lastX; + m_lastY = lastY; +} + +} // namespace WebCore |