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      1 /*
      2  * Copyright (C) 2010 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  *
      8  * 1.  Redistributions of source code must retain the above copyright
      9  *     notice, this list of conditions and the following disclaimer.
     10  * 2.  Redistributions in binary form must reproduce the above copyright
     11  *     notice, this list of conditions and the following disclaimer in the
     12  *     documentation and/or other materials provided with the distribution.
     13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
     14  *     its contributors may be used to endorse or promote products derived
     15  *     from this software without specific prior written permission.
     16  *
     17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
     18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
     19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
     20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
     21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
     22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
     23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include "config.h"
     30 
     31 #if ENABLE(WEB_AUDIO)
     32 
     33 #include "AudioChannel.h"
     34 
     35 #include "VectorMath.h"
     36 #include <algorithm>
     37 #include <math.h>
     38 #include <wtf/OwnPtr.h>
     39 
     40 namespace WebCore {
     41 
     42 using namespace VectorMath;
     43 
     44 void AudioChannel::scale(double scale)
     45 {
     46     float s = static_cast<float>(scale);
     47     vsmul(data(), 1, &s, data(), 1, length());
     48 }
     49 
     50 void AudioChannel::copyFrom(const AudioChannel* sourceChannel)
     51 {
     52     bool isSafe = (sourceChannel && sourceChannel->length() >= length());
     53     ASSERT(isSafe);
     54     if (!isSafe)
     55         return;
     56 
     57     memcpy(data(), sourceChannel->data(), sizeof(float) * length());
     58 }
     59 
     60 void AudioChannel::copyFromRange(const AudioChannel* sourceChannel, unsigned startFrame, unsigned endFrame)
     61 {
     62     // Check that range is safe for reading from sourceChannel.
     63     bool isRangeSafe = sourceChannel && startFrame < endFrame && endFrame <= sourceChannel->length();
     64     ASSERT(isRangeSafe);
     65     if (!isRangeSafe)
     66         return;
     67 
     68     // Check that this channel has enough space.
     69     size_t rangeLength = endFrame - startFrame;
     70     bool isRangeLengthSafe = rangeLength <= length();
     71     ASSERT(isRangeLengthSafe);
     72     if (!isRangeLengthSafe)
     73         return;
     74 
     75     const float* source = sourceChannel->data();
     76     float* destination = data();
     77     memcpy(destination, source + startFrame, sizeof(float) * rangeLength);
     78 }
     79 
     80 void AudioChannel::sumFrom(const AudioChannel* sourceChannel)
     81 {
     82     bool isSafe = sourceChannel && sourceChannel->length() >= length();
     83     ASSERT(isSafe);
     84     if (!isSafe)
     85         return;
     86 
     87     vadd(data(), 1, sourceChannel->data(), 1, data(), 1, length());
     88 }
     89 
     90 float AudioChannel::maxAbsValue() const
     91 {
     92     const float* p = data();
     93     int n = length();
     94 
     95     float max = 0.0f;
     96     while (n--)
     97         max = std::max(max, fabsf(*p++));
     98 
     99     return max;
    100 }
    101 
    102 } // WebCore
    103 
    104 #endif // ENABLE(WEB_AUDIO)
    105