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/*
* Copyright (C) 2010 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 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.
*/
#ifndef AudioArray_h
#define AudioArray_h
#include <string.h>
#include <wtf/CheckedArithmetic.h>
#include <wtf/FastMalloc.h>
#include <wtf/Vector.h>
namespace WebCore {
template<typename T>
class AudioArray {
public:
AudioArray() : m_allocation(0), m_alignedData(0), m_size(0) { }
explicit AudioArray(size_t n) : m_allocation(0), m_alignedData(0), m_size(0)
{
allocate(n);
}
~AudioArray()
{
fastFree(m_allocation);
}
// It's OK to call allocate() multiple times, but data will *not* be copied from an initial allocation
// if re-allocated. Allocations are zero-initialized.
void allocate(Checked<size_t> n)
{
Checked<unsigned> initialSize = sizeof(T) * n;
const size_t alignment = 16;
if (m_allocation)
fastFree(m_allocation);
bool isAllocationGood = false;
while (!isAllocationGood) {
// Initially we try to allocate the exact size, but if it's not aligned
// then we'll have to reallocate and from then on allocate extra.
static size_t extraAllocationBytes = 0;
T* allocation = static_cast<T*>(fastMalloc((initialSize + extraAllocationBytes).unsafeGet()));
if (!allocation)
CRASH();
T* alignedData = alignedAddress(allocation, alignment);
if (alignedData == allocation || extraAllocationBytes == alignment) {
m_allocation = allocation;
m_alignedData = alignedData;
m_size = n.unsafeGet();
isAllocationGood = true;
zero();
} else {
extraAllocationBytes = alignment; // always allocate extra after the first alignment failure.
fastFree(allocation);
}
}
}
T* data() { return m_alignedData; }
const T* data() const { return m_alignedData; }
size_t size() const { return m_size; }
T& at(size_t i)
{
// Note that although it is a size_t, m_size is now guaranteed to be
// no greater than max unsigned. This guarantee is enforced in allocate().
ASSERT_WITH_SECURITY_IMPLICATION(i < size());
return data()[i];
}
T& operator[](size_t i) { return at(i); }
void zero()
{
// This multiplication is made safe by the check in allocate().
memset(this->data(), 0, sizeof(T) * this->size());
}
void zeroRange(unsigned start, unsigned end)
{
bool isSafe = (start <= end) && (end <= this->size());
ASSERT(isSafe);
if (!isSafe)
return;
// This expression cannot overflow because end - start cannot be
// greater than m_size, which is safe due to the check in allocate().
memset(this->data() + start, 0, sizeof(T) * (end - start));
}
void copyToRange(const T* sourceData, unsigned start, unsigned end)
{
bool isSafe = (start <= end) && (end <= this->size());
ASSERT(isSafe);
if (!isSafe)
return;
// This expression cannot overflow because end - start cannot be
// greater than m_size, which is safe due to the check in allocate().
memcpy(this->data() + start, sourceData, sizeof(T) * (end - start));
}
private:
static T* alignedAddress(T* address, intptr_t alignment)
{
intptr_t value = reinterpret_cast<intptr_t>(address);
return reinterpret_cast<T*>((value + alignment - 1) & ~(alignment - 1));
}
T* m_allocation;
T* m_alignedData;
size_t m_size;
};
typedef AudioArray<float> AudioFloatArray;
typedef AudioArray<double> AudioDoubleArray;
} // WebCore
#endif // AudioArray_h
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