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 AudioArray_h 30 #define AudioArray_h 31 32 #include <string.h> 33 #include "wtf/FastMalloc.h" 34 #include "wtf/Vector.h" 35 36 namespace blink { 37 38 template<typename T> 39 class AudioArray { 40 public: AudioArray()41 AudioArray() : m_allocation(0), m_alignedData(0), m_size(0) { } AudioArray(size_t n)42 explicit AudioArray(size_t n) : m_allocation(0), m_alignedData(0), m_size(0) 43 { 44 allocate(n); 45 } 46 ~AudioArray()47 ~AudioArray() 48 { 49 fastFree(m_allocation); 50 } 51 52 // It's OK to call allocate() multiple times, but data will *not* be copied from an initial allocation 53 // if re-allocated. Allocations are zero-initialized. allocate(size_t n)54 void allocate(size_t n) 55 { 56 // Although n is a size_t, its true limit is max unsigned because we use unsigned in zeroRange() 57 // and copyToRange(). Also check for integer overflow. 58 if (n > std::numeric_limits<unsigned>::max() / sizeof(T)) 59 CRASH(); 60 61 unsigned initialSize = sizeof(T) * n; 62 63 #if USE(WEBAUDIO_FFMPEG) || USE(WEBAUDIO_OPENMAX_DL_FFT) 64 const size_t alignment = 32; 65 #else 66 const size_t alignment = 16; 67 #endif 68 69 if (m_allocation) 70 fastFree(m_allocation); 71 72 bool isAllocationGood = false; 73 74 while (!isAllocationGood) { 75 // Initially we try to allocate the exact size, but if it's not aligned 76 // then we'll have to reallocate and from then on allocate extra. 77 static size_t extraAllocationBytes = 0; 78 79 // Again, check for integer overflow. 80 if (initialSize + extraAllocationBytes < initialSize) 81 CRASH(); 82 83 T* allocation = static_cast<T*>(fastMalloc(initialSize + extraAllocationBytes)); 84 if (!allocation) 85 CRASH(); 86 T* alignedData = alignedAddress(allocation, alignment); 87 88 if (alignedData == allocation || extraAllocationBytes == alignment) { 89 m_allocation = allocation; 90 m_alignedData = alignedData; 91 m_size = n; 92 isAllocationGood = true; 93 zero(); 94 } else { 95 extraAllocationBytes = alignment; // always allocate extra after the first alignment failure. 96 fastFree(allocation); 97 } 98 } 99 } 100 data()101 T* data() { return m_alignedData; } data()102 const T* data() const { return m_alignedData; } size()103 size_t size() const { return m_size; } 104 at(size_t i)105 T& at(size_t i) 106 { 107 // Note that although it is a size_t, m_size is now guaranteed to be 108 // no greater than max unsigned. This guarantee is enforced in allocate(). 109 ASSERT_WITH_SECURITY_IMPLICATION(i < size()); 110 return data()[i]; 111 } 112 113 T& operator[](size_t i) { return at(i); } 114 zero()115 void zero() 116 { 117 // This multiplication is made safe by the check in allocate(). 118 memset(this->data(), 0, sizeof(T) * this->size()); 119 } 120 zeroRange(unsigned start,unsigned end)121 void zeroRange(unsigned start, unsigned end) 122 { 123 bool isSafe = (start <= end) && (end <= this->size()); 124 ASSERT(isSafe); 125 if (!isSafe) 126 return; 127 128 // This expression cannot overflow because end - start cannot be 129 // greater than m_size, which is safe due to the check in allocate(). 130 memset(this->data() + start, 0, sizeof(T) * (end - start)); 131 } 132 copyToRange(const T * sourceData,unsigned start,unsigned end)133 void copyToRange(const T* sourceData, unsigned start, unsigned end) 134 { 135 bool isSafe = (start <= end) && (end <= this->size()); 136 ASSERT(isSafe); 137 if (!isSafe) 138 return; 139 140 // This expression cannot overflow because end - start cannot be 141 // greater than m_size, which is safe due to the check in allocate(). 142 memcpy(this->data() + start, sourceData, sizeof(T) * (end - start)); 143 } 144 145 private: alignedAddress(T * address,intptr_t alignment)146 static T* alignedAddress(T* address, intptr_t alignment) 147 { 148 intptr_t value = reinterpret_cast<intptr_t>(address); 149 return reinterpret_cast<T*>((value + alignment - 1) & ~(alignment - 1)); 150 } 151 152 T* m_allocation; 153 T* m_alignedData; 154 size_t m_size; 155 }; 156 157 typedef AudioArray<float> AudioFloatArray; 158 typedef AudioArray<double> AudioDoubleArray; 159 160 } // namespace blink 161 162 #endif // AudioArray_h 163