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/*
* Copyright (C) 2014 Apple 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.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. 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 INC. 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 GCSegmentedArray_h
#define GCSegmentedArray_h
#include <wtf/DoublyLinkedList.h>
#include <wtf/Vector.h>
namespace JSC {
template <typename T>
class GCArraySegment : public DoublyLinkedListNode<GCArraySegment<T>> {
friend class WTF::DoublyLinkedListNode<GCArraySegment<T>>;
public:
GCArraySegment()
: DoublyLinkedListNode<GCArraySegment<T>>()
#if !ASSERT_DISABLED
, m_top(0)
#endif
{
}
static GCArraySegment* create();
static void destroy(GCArraySegment*);
T* data()
{
return bitwise_cast<T*>(this + 1);
}
static const size_t blockSize = 4 * KB;
GCArraySegment* m_prev;
GCArraySegment* m_next;
#if !ASSERT_DISABLED
size_t m_top;
#endif
};
template <typename T> class GCSegmentedArrayIterator;
template <typename T>
class GCSegmentedArray {
friend class GCSegmentedArrayIterator<T>;
friend class GCSegmentedArrayIterator<const T>;
public:
GCSegmentedArray();
~GCSegmentedArray();
void append(T);
bool canRemoveLast();
const T removeLast();
bool refill();
size_t size();
bool isEmpty();
void fillVector(Vector<T>&);
void clear();
typedef GCSegmentedArrayIterator<T> iterator;
iterator begin() const { return GCSegmentedArrayIterator<T>(m_segments.head(), m_top); }
iterator end() const { return GCSegmentedArrayIterator<T>(); }
protected:
template <size_t size> struct CapacityFromSize {
static const size_t value = (size - sizeof(GCArraySegment<T>)) / sizeof(T);
};
void expand();
size_t postIncTop();
size_t preDecTop();
void setTopForFullSegment();
void setTopForEmptySegment();
size_t top();
void validatePrevious();
DoublyLinkedList<GCArraySegment<T>> m_segments;
JS_EXPORT_PRIVATE static const size_t s_segmentCapacity = CapacityFromSize<GCArraySegment<T>::blockSize>::value;
size_t m_top;
size_t m_numberOfSegments;
};
template <typename T>
class GCSegmentedArrayIterator {
friend class GCSegmentedArray<T>;
public:
GCSegmentedArrayIterator()
: m_currentSegment(0)
, m_currentOffset(0)
{
}
T& get() { return m_currentSegment->data()[m_currentOffset]; }
T& operator*() { return get(); }
T& operator->() { return get(); }
bool operator==(const GCSegmentedArrayIterator& other)
{
return m_currentSegment == other.m_currentSegment && m_currentOffset == other.m_currentOffset;
}
bool operator!=(const GCSegmentedArrayIterator& other)
{
return !(*this == other);
}
GCSegmentedArrayIterator& operator++()
{
ASSERT(m_currentSegment);
m_currentOffset++;
if (m_currentOffset >= m_offsetLimit) {
m_currentSegment = m_currentSegment->next();
m_currentOffset = 0;
m_offsetLimit = GCSegmentedArray<T>::s_segmentCapacity;
}
return *this;
}
private:
GCSegmentedArrayIterator(GCArraySegment<T>* start, size_t top)
: m_currentSegment(start)
, m_currentOffset(0)
, m_offsetLimit(top)
{
if (!m_offsetLimit)
m_currentSegment = nullptr;
}
GCArraySegment<T>* m_currentSegment;
size_t m_currentOffset;
size_t m_offsetLimit;
};
} // namespace JSC
#endif // GCSegmentedArray_h
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