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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 "platform/audio/AudioChannel.h"
     34 
     35 #include <math.h>
     36 #include <algorithm>
     37 #include "platform/audio/VectorMath.h"
     38 #include "wtf/OwnPtr.h"
     39 
     40 namespace blink {
     41 
     42 using namespace VectorMath;
     43 
     44 void AudioChannel::resizeSmaller(size_t newLength)
     45 {
     46     ASSERT(newLength <= m_length);
     47     if (newLength <= m_length)
     48         m_length = newLength;
     49 }
     50 
     51 void AudioChannel::scale(float scale)
     52 {
     53     if (isSilent())
     54         return;
     55 
     56     vsmul(data(), 1, &scale, mutableData(), 1, length());
     57 }
     58 
     59 void AudioChannel::copyFrom(const AudioChannel* sourceChannel)
     60 {
     61     bool isSafe = (sourceChannel && sourceChannel->length() >= length());
     62     ASSERT(isSafe);
     63     if (!isSafe)
     64         return;
     65 
     66     if (sourceChannel->isSilent()) {
     67         zero();
     68         return;
     69     }
     70     memcpy(mutableData(), sourceChannel->data(), sizeof(float) * length());
     71 }
     72 
     73 void AudioChannel::copyFromRange(const AudioChannel* sourceChannel, unsigned startFrame, unsigned endFrame)
     74 {
     75     // Check that range is safe for reading from sourceChannel.
     76     bool isRangeSafe = sourceChannel && startFrame < endFrame && endFrame <= sourceChannel->length();
     77     ASSERT(isRangeSafe);
     78     if (!isRangeSafe)
     79         return;
     80 
     81     if (sourceChannel->isSilent() && isSilent())
     82         return;
     83 
     84     // Check that this channel has enough space.
     85     size_t rangeLength = endFrame - startFrame;
     86     bool isRangeLengthSafe = rangeLength <= length();
     87     ASSERT(isRangeLengthSafe);
     88     if (!isRangeLengthSafe)
     89         return;
     90 
     91     const float* source = sourceChannel->data();
     92     float* destination = mutableData();
     93 
     94     if (sourceChannel->isSilent()) {
     95         if (rangeLength == length())
     96             zero();
     97         else
     98             memset(destination, 0, sizeof(float) * rangeLength);
     99     } else
    100         memcpy(destination, source + startFrame, sizeof(float) * rangeLength);
    101 }
    102 
    103 void AudioChannel::sumFrom(const AudioChannel* sourceChannel)
    104 {
    105     bool isSafe = sourceChannel && sourceChannel->length() >= length();
    106     ASSERT(isSafe);
    107     if (!isSafe)
    108         return;
    109 
    110     if (sourceChannel->isSilent())
    111         return;
    112 
    113     if (isSilent())
    114         copyFrom(sourceChannel);
    115     else
    116         vadd(data(), 1, sourceChannel->data(), 1, mutableData(), 1, length());
    117 }
    118 
    119 float AudioChannel::maxAbsValue() const
    120 {
    121     if (isSilent())
    122         return 0;
    123 
    124     float max = 0;
    125 
    126     vmaxmgv(data(), 1, &max, length());
    127 
    128     return max;
    129 }
    130 
    131 } // namespace blink
    132 
    133 #endif // ENABLE(WEB_AUDIO)
    134