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/*
* Copyright (C) 2008 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.
* 3. Neither the name of Apple Computer, 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
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef SegmentedVector_h
#define SegmentedVector_h
#include <wtf/Vector.h>
namespace WTF {
// An iterator for SegmentedVector. It supports only the pre ++ operator
template <typename T, size_t SegmentSize = 8, size_t InlineCapacity = 32> class SegmentedVector;
template <typename T, size_t SegmentSize = 8, size_t InlineCapacity = 32> class SegmentedVectorIterator {
private:
friend class SegmentedVector<T, SegmentSize, InlineCapacity>;
public:
typedef SegmentedVectorIterator<T, SegmentSize, InlineCapacity> Iterator;
~SegmentedVectorIterator() { }
T& operator*() const { return m_vector.m_segments.at(m_segment)->at(m_index); }
T* operator->() const { return &m_vector.m_segments.at(m_segment)->at(m_index); }
// Only prefix ++ operator supported
Iterator& operator++()
{
ASSERT(m_index != SegmentSize);
++m_index;
if (m_index >= m_vector.m_segments.at(m_segment)->size()) {
if (m_segment + 1 < m_vector.m_segments.size()) {
ASSERT(m_vector.m_segments.at(m_segment)->size() > 0);
++m_segment;
m_index = 0;
} else {
// Points to the "end" symbol
m_segment = 0;
m_index = SegmentSize;
}
}
return *this;
}
bool operator==(const Iterator& other) const
{
return m_index == other.m_index && m_segment == other.m_segment && &m_vector == &other.m_vector;
}
bool operator!=(const Iterator& other) const
{
return m_index != other.m_index || m_segment != other.m_segment || &m_vector != &other.m_vector;
}
SegmentedVectorIterator& operator=(const SegmentedVectorIterator<T, SegmentSize, InlineCapacity>& other)
{
m_vector = other.m_vector;
m_segment = other.m_segment;
m_index = other.m_index;
return *this;
}
private:
SegmentedVectorIterator(SegmentedVector<T, SegmentSize, InlineCapacity>& vector, size_t segment, size_t index)
: m_vector(vector)
, m_segment(segment)
, m_index(index)
{
}
SegmentedVector<T, SegmentSize, InlineCapacity>& m_vector;
size_t m_segment;
size_t m_index;
};
// SegmentedVector is just like Vector, but it doesn't move the values
// stored in its buffer when it grows. Therefore, it is safe to keep
// pointers into a SegmentedVector. The default tuning values are
// optimized for segmented vectors that get large; you may want to use
// SegmentedVector<thingy, 1, 0> if you don't expect a lot of entries.
template <typename T, size_t SegmentSize, size_t InlineCapacity>
class SegmentedVector {
friend class SegmentedVectorIterator<T, SegmentSize, InlineCapacity>;
public:
typedef SegmentedVectorIterator<T, SegmentSize, InlineCapacity> Iterator;
SegmentedVector()
: m_size(0)
{
m_segments.append(&m_inlineSegment);
}
~SegmentedVector()
{
deleteAllSegments();
}
size_t size() const { return m_size; }
bool isEmpty() const { return !size(); }
T& at(size_t index)
{
if (index < SegmentSize)
return m_inlineSegment[index];
return segmentFor(index)->at(subscriptFor(index));
}
const T& at(size_t index) const
{
return const_cast<SegmentedVector<T, SegmentSize, InlineCapacity>*>(this)->at(index);
}
T& operator[](size_t index)
{
return at(index);
}
const T& operator[](size_t index) const
{
return at(index);
}
T& last()
{
return at(size() - 1);
}
template <typename U> void append(const U& value)
{
++m_size;
if (m_size <= SegmentSize) {
m_inlineSegment.uncheckedAppend(value);
return;
}
if (!segmentExistsFor(m_size - 1))
m_segments.append(new Segment);
segmentFor(m_size - 1)->uncheckedAppend(value);
}
T& alloc()
{
append<T>(T());
return last();
}
void removeLast()
{
if (m_size <= SegmentSize)
m_inlineSegment.removeLast();
else
segmentFor(m_size - 1)->removeLast();
--m_size;
}
void grow(size_t size)
{
ASSERT(size > m_size);
ensureSegmentsFor(size);
m_size = size;
}
void clear()
{
deleteAllSegments();
m_segments.resize(1);
m_inlineSegment.clear();
m_size = 0;
}
Iterator begin()
{
return Iterator(*this, 0, m_size ? 0 : SegmentSize);
}
Iterator end()
{
return Iterator(*this, 0, SegmentSize);
}
void shrinkToFit()
{
m_segments.shrinkToFit();
}
private:
typedef Vector<T, SegmentSize> Segment;
void deleteAllSegments()
{
// Skip the first segment, because it's our inline segment, which was
// not created by new.
for (size_t i = 1; i < m_segments.size(); i++)
delete m_segments[i];
}
bool segmentExistsFor(size_t index)
{
return index / SegmentSize < m_segments.size();
}
Segment* segmentFor(size_t index)
{
return m_segments[index / SegmentSize];
}
size_t subscriptFor(size_t index)
{
return index % SegmentSize;
}
void ensureSegmentsFor(size_t size)
{
size_t segmentCount = m_size / SegmentSize;
if (m_size % SegmentSize)
++segmentCount;
segmentCount = std::max<size_t>(segmentCount, 1); // We always have at least our inline segment.
size_t neededSegmentCount = size / SegmentSize;
if (size % SegmentSize)
++neededSegmentCount;
// Fill up to N - 1 segments.
size_t end = neededSegmentCount - 1;
for (size_t i = segmentCount - 1; i < end; ++i)
ensureSegment(i, SegmentSize);
// Grow segment N to accomodate the remainder.
ensureSegment(end, subscriptFor(size - 1) + 1);
}
void ensureSegment(size_t segmentIndex, size_t size)
{
ASSERT(segmentIndex <= m_segments.size());
if (segmentIndex == m_segments.size())
m_segments.append(new Segment);
m_segments[segmentIndex]->grow(size);
}
size_t m_size;
Segment m_inlineSegment;
Vector<Segment*, InlineCapacity> m_segments;
};
} // namespace WTF
using WTF::SegmentedVector;
#endif // SegmentedVector_h