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 #ifndef AudioChannel_h 30 #define AudioChannel_h 31 32 #include "AudioArray.h" 33 #include <wtf/PassOwnPtr.h> 34 35 namespace WebCore { 36 37 // An AudioChannel represents a buffer of non-interleaved floating-point audio samples. 38 // The PCM samples are normally assumed to be in a nominal range -1.0 -> +1.0 39 class AudioChannel { 40 WTF_MAKE_NONCOPYABLE(AudioChannel); 41 public: 42 // Memory can be externally referenced, or can be internally allocated with an AudioFloatArray. 43 44 // Reference an external buffer. 45 AudioChannel(float* storage, size_t length) 46 : m_length(length), m_rawPointer(storage) { } 47 48 // Manage storage for us. 49 explicit AudioChannel(size_t length) 50 : m_length(length) 51 , m_rawPointer(0) 52 { 53 m_memBuffer = adoptPtr(new AudioFloatArray(length)); 54 } 55 56 // A "blank" audio channel -- must call set() before it's useful... 57 AudioChannel() 58 : m_length(0) 59 , m_rawPointer(0) 60 { 61 } 62 63 // Redefine the memory for this channel. 64 // storage represents external memory not managed by this object. 65 void set(float* storage, size_t length) 66 { 67 m_memBuffer.clear(); // cleanup managed storage 68 m_rawPointer = storage; 69 m_length = length; 70 } 71 72 // How many sample-frames do we contain? 73 size_t length() const { return m_length; } 74 75 // Direct access to PCM sample data 76 float* data() { return m_rawPointer ? m_rawPointer : m_memBuffer->data(); } 77 const float* data() const { return m_rawPointer ? m_rawPointer : m_memBuffer->data(); } 78 79 // Zeroes out all sample values in buffer. 80 void zero() 81 { 82 if (m_memBuffer.get()) 83 m_memBuffer->zero(); 84 else 85 memset(m_rawPointer, 0, sizeof(float) * m_length); 86 } 87 88 // Scales all samples by the same amount. 89 void scale(double scale); 90 91 // A simple memcpy() from the source channel 92 void copyFrom(const AudioChannel* sourceChannel); 93 94 // Copies the given range from the source channel. 95 void copyFromRange(const AudioChannel* sourceChannel, unsigned startFrame, unsigned endFrame); 96 97 // Sums (with unity gain) from the source channel. 98 void sumFrom(const AudioChannel* sourceChannel); 99 100 // Returns maximum absolute value (useful for normalization). 101 float maxAbsValue() const; 102 103 private: 104 size_t m_length; 105 106 float* m_rawPointer; 107 OwnPtr<AudioFloatArray> m_memBuffer; 108 }; 109 110 } // WebCore 111 112 #endif // AudioChannel_h 113
