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/*
* Copyright (C) 2007-2017 Apple Inc. All rights reserved.
* Copyright (C) 2009 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.
*/
#pragma once
// FIXME: Could move what Vector and Deque share into a separate file.
// Deque doesn't actually use Vector.
#include <algorithm>
#include <iterator>
#include <wtf/Vector.h>
namespace WTF {
template<typename T, size_t inlineCapacity> class DequeIteratorBase;
template<typename T, size_t inlineCapacity> class DequeIterator;
template<typename T, size_t inlineCapacity> class DequeConstIterator;
template<typename T, size_t inlineCapacity = 0>
class Deque {
WTF_MAKE_FAST_ALLOCATED;
public:
typedef T ValueType;
typedef DequeIterator<T, inlineCapacity> iterator;
typedef DequeConstIterator<T, inlineCapacity> const_iterator;
typedef std::reverse_iterator<iterator> reverse_iterator;
typedef std::reverse_iterator<const_iterator> const_reverse_iterator;
Deque();
Deque(std::initializer_list<T>);
Deque(const Deque&);
Deque(Deque&&);
~Deque();
Deque& operator=(const Deque&);
Deque& operator=(Deque&&);
void swap(Deque&);
size_t size() const { return m_start <= m_end ? m_end - m_start : m_end + m_buffer.capacity() - m_start; }
bool isEmpty() const { return m_start == m_end; }
iterator begin() { return iterator(this, m_start); }
iterator end() { return iterator(this, m_end); }
const_iterator begin() const { return const_iterator(this, m_start); }
const_iterator end() const { return const_iterator(this, m_end); }
reverse_iterator rbegin() { return reverse_iterator(end()); }
reverse_iterator rend() { return reverse_iterator(begin()); }
const_reverse_iterator rbegin() const { return const_reverse_iterator(end()); }
const_reverse_iterator rend() const { return const_reverse_iterator(begin()); }
template<typename U> bool contains(const U&) const;
T& first() { ASSERT(m_start != m_end); return m_buffer.buffer()[m_start]; }
const T& first() const { ASSERT(m_start != m_end); return m_buffer.buffer()[m_start]; }
T takeFirst();
T& last() { ASSERT(m_start != m_end); return *(--end()); }
const T& last() const { ASSERT(m_start != m_end); return *(--end()); }
T takeLast();
void append(T&& value) { append<T>(std::forward<T>(value)); }
template<typename U> void append(U&&);
template<typename U> void prepend(U&&);
void removeFirst();
void removeLast();
void remove(iterator&);
void remove(const_iterator&);
template<typename Func> void removeAllMatching(const Func&);
// This is a priority enqueue. The callback is given a value, and if it returns true, then this
// will put the appended value before that value. It will keep bubbling until the callback returns
// false or the value ends up at the head of the queue.
template<typename U, typename Func>
void appendAndBubble(U&&, const Func&);
// Remove and return the first element for which the callback returns true. Returns a null version of
// T if it the callback always returns false.
template<typename Func>
T takeFirst(const Func&);
// Remove and return the last element for which the callback returns true. Returns a null version of
// T if it the callback always returns false.
template<typename Func>
T takeLast(const Func&);
void clear();
template<typename Predicate> iterator findIf(const Predicate&);
template<typename Predicate> const_iterator findIf(const Predicate&) const;
private:
friend class DequeIteratorBase<T, inlineCapacity>;
typedef VectorBuffer<T, inlineCapacity> Buffer;
typedef VectorTypeOperations<T> TypeOperations;
typedef DequeIteratorBase<T, inlineCapacity> IteratorBase;
void remove(size_t position);
void invalidateIterators();
void destroyAll();
void checkValidity() const;
void checkIndexValidity(size_t) const;
void expandCapacityIfNeeded();
void expandCapacity();
size_t m_start;
size_t m_end;
Buffer m_buffer;
#ifndef NDEBUG
mutable IteratorBase* m_iterators;
#endif
};
template<typename T, size_t inlineCapacity = 0>
class DequeIteratorBase {
protected:
DequeIteratorBase();
DequeIteratorBase(const Deque<T, inlineCapacity>*, size_t);
DequeIteratorBase(const DequeIteratorBase&);
DequeIteratorBase& operator=(const DequeIteratorBase&);
~DequeIteratorBase();
void assign(const DequeIteratorBase& other) { *this = other; }
void increment();
void decrement();
T* before() const;
T* after() const;
bool isEqual(const DequeIteratorBase&) const;
private:
void addToIteratorsList();
void removeFromIteratorsList();
void checkValidity() const;
void checkValidity(const DequeIteratorBase&) const;
Deque<T, inlineCapacity>* m_deque;
size_t m_index;
friend class Deque<T, inlineCapacity>;
#ifndef NDEBUG
mutable DequeIteratorBase* m_next;
mutable DequeIteratorBase* m_previous;
#endif
};
template<typename T, size_t inlineCapacity = 0>
class DequeIterator : public DequeIteratorBase<T, inlineCapacity> {
private:
typedef DequeIteratorBase<T, inlineCapacity> Base;
typedef DequeIterator<T, inlineCapacity> Iterator;
public:
typedef ptrdiff_t difference_type;
typedef T value_type;
typedef T* pointer;
typedef T& reference;
typedef std::bidirectional_iterator_tag iterator_category;
DequeIterator(Deque<T, inlineCapacity>* deque, size_t index)
: Base(deque, index) { }
DequeIterator(const Iterator& other) : Base(other) { }
DequeIterator& operator=(const Iterator& other) { Base::assign(other); return *this; }
T& operator*() const { return *Base::after(); }
T* operator->() const { return Base::after(); }
bool operator==(const Iterator& other) const { return Base::isEqual(other); }
bool operator!=(const Iterator& other) const { return !Base::isEqual(other); }
Iterator& operator++() { Base::increment(); return *this; }
// postfix ++ intentionally omitted
Iterator& operator--() { Base::decrement(); return *this; }
// postfix -- intentionally omitted
};
template<typename T, size_t inlineCapacity = 0>
class DequeConstIterator : public DequeIteratorBase<T, inlineCapacity> {
private:
typedef DequeIteratorBase<T, inlineCapacity> Base;
typedef DequeConstIterator<T, inlineCapacity> Iterator;
typedef DequeIterator<T, inlineCapacity> NonConstIterator;
public:
typedef ptrdiff_t difference_type;
typedef T value_type;
typedef const T* pointer;
typedef const T& reference;
typedef std::bidirectional_iterator_tag iterator_category;
DequeConstIterator(const Deque<T, inlineCapacity>* deque, size_t index)
: Base(deque, index) { }
DequeConstIterator(const Iterator& other) : Base(other) { }
DequeConstIterator(const NonConstIterator& other) : Base(other) { }
DequeConstIterator& operator=(const Iterator& other) { Base::assign(other); return *this; }
DequeConstIterator& operator=(const NonConstIterator& other) { Base::assign(other); return *this; }
const T& operator*() const { return *Base::after(); }
const T* operator->() const { return Base::after(); }
bool operator==(const Iterator& other) const { return Base::isEqual(other); }
bool operator!=(const Iterator& other) const { return !Base::isEqual(other); }
Iterator& operator++() { Base::increment(); return *this; }
// postfix ++ intentionally omitted
Iterator& operator--() { Base::decrement(); return *this; }
// postfix -- intentionally omitted
};
#ifdef NDEBUG
template<typename T, size_t inlineCapacity> inline void Deque<T, inlineCapacity>::checkValidity() const { }
template<typename T, size_t inlineCapacity> inline void Deque<T, inlineCapacity>::checkIndexValidity(size_t) const { }
template<typename T, size_t inlineCapacity> inline void Deque<T, inlineCapacity>::invalidateIterators() { }
#else
template<typename T, size_t inlineCapacity>
void Deque<T, inlineCapacity>::checkValidity() const
{
// In this implementation a capacity of 1 would confuse append() and
// other places that assume the index after capacity - 1 is 0.
ASSERT(m_buffer.capacity() != 1);
if (!m_buffer.capacity()) {
ASSERT(!m_start);
ASSERT(!m_end);
} else {
ASSERT(m_start < m_buffer.capacity());
ASSERT(m_end < m_buffer.capacity());
}
}
template<typename T, size_t inlineCapacity>
void Deque<T, inlineCapacity>::checkIndexValidity(size_t index) const
{
ASSERT_UNUSED(index, index <= m_buffer.capacity());
if (m_start <= m_end) {
ASSERT(index >= m_start);
ASSERT(index <= m_end);
} else {
ASSERT(index >= m_start || index <= m_end);
}
}
template<typename T, size_t inlineCapacity>
void Deque<T, inlineCapacity>::invalidateIterators()
{
IteratorBase* next;
for (IteratorBase* p = m_iterators; p; p = next) {
next = p->m_next;
p->m_deque = 0;
p->m_next = 0;
p->m_previous = 0;
}
m_iterators = 0;
}
#endif
template<typename T, size_t inlineCapacity>
inline Deque<T, inlineCapacity>::Deque()
: m_start(0)
, m_end(0)
#ifndef NDEBUG
, m_iterators(0)
#endif
{
checkValidity();
}
template<typename T, size_t inlineCapacity>
inline Deque<T, inlineCapacity>::Deque(std::initializer_list<T> initializerList)
: Deque()
{
for (auto& element : initializerList)
append(element);
}
template<typename T, size_t inlineCapacity>
inline Deque<T, inlineCapacity>::Deque(const Deque& other)
: m_start(other.m_start)
, m_end(other.m_end)
, m_buffer(other.m_buffer.capacity())
#ifndef NDEBUG
, m_iterators(0)
#endif
{
const T* otherBuffer = other.m_buffer.buffer();
if (m_start <= m_end)
TypeOperations::uninitializedCopy(otherBuffer + m_start, otherBuffer + m_end, m_buffer.buffer() + m_start);
else {
TypeOperations::uninitializedCopy(otherBuffer, otherBuffer + m_end, m_buffer.buffer());
TypeOperations::uninitializedCopy(otherBuffer + m_start, otherBuffer + m_buffer.capacity(), m_buffer.buffer() + m_start);
}
}
template<typename T, size_t inlineCapacity>
inline Deque<T, inlineCapacity>::Deque(Deque&& other)
: Deque()
{
swap(other);
}
template<typename T, size_t inlineCapacity>
inline auto Deque<T, inlineCapacity>::operator=(const Deque& other) -> Deque&
{
// FIXME: This is inefficient if we're using an inline buffer and T is
// expensive to copy since it will copy the buffer twice instead of once.
Deque<T, inlineCapacity> copy(other);
swap(copy);
return *this;
}
template<typename T, size_t inlineCapacity>
inline auto Deque<T, inlineCapacity>::operator=(Deque&& other) -> Deque&
{
swap(other);
return *this;
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::destroyAll()
{
if (m_start <= m_end)
TypeOperations::destruct(m_buffer.buffer() + m_start, m_buffer.buffer() + m_end);
else {
TypeOperations::destruct(m_buffer.buffer(), m_buffer.buffer() + m_end);
TypeOperations::destruct(m_buffer.buffer() + m_start, m_buffer.buffer() + m_buffer.capacity());
}
}
template<typename T, size_t inlineCapacity>
inline Deque<T, inlineCapacity>::~Deque()
{
checkValidity();
invalidateIterators();
destroyAll();
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::swap(Deque<T, inlineCapacity>& other)
{
checkValidity();
other.checkValidity();
invalidateIterators();
std::swap(m_start, other.m_start);
std::swap(m_end, other.m_end);
m_buffer.swap(other.m_buffer, 0, 0);
checkValidity();
other.checkValidity();
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::clear()
{
checkValidity();
invalidateIterators();
destroyAll();
m_start = 0;
m_end = 0;
m_buffer.deallocateBuffer(m_buffer.buffer());
checkValidity();
}
template<typename T, size_t inlineCapacity>
template<typename Predicate>
inline auto Deque<T, inlineCapacity>::findIf(const Predicate& predicate) -> iterator
{
return std::find_if(begin(), end(), predicate);
}
template<typename T, size_t inlineCapacity>
template<typename Predicate>
inline auto Deque<T, inlineCapacity>::findIf(const Predicate& predicate) const -> const_iterator
{
return std::find_if(begin(), end(), predicate);
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::expandCapacityIfNeeded()
{
if (m_start) {
if (m_end + 1 != m_start)
return;
} else if (m_end) {
if (m_end != m_buffer.capacity() - 1)
return;
} else if (m_buffer.capacity())
return;
expandCapacity();
}
template<typename T, size_t inlineCapacity>
void Deque<T, inlineCapacity>::expandCapacity()
{
checkValidity();
size_t oldCapacity = m_buffer.capacity();
T* oldBuffer = m_buffer.buffer();
m_buffer.allocateBuffer(std::max(static_cast<size_t>(16), oldCapacity + oldCapacity / 4 + 1));
if (m_start <= m_end)
TypeOperations::move(oldBuffer + m_start, oldBuffer + m_end, m_buffer.buffer() + m_start);
else {
TypeOperations::move(oldBuffer, oldBuffer + m_end, m_buffer.buffer());
size_t newStart = m_buffer.capacity() - (oldCapacity - m_start);
TypeOperations::move(oldBuffer + m_start, oldBuffer + oldCapacity, m_buffer.buffer() + newStart);
m_start = newStart;
}
m_buffer.deallocateBuffer(oldBuffer);
checkValidity();
}
template<typename T, size_t inlineCapacity>
template<typename U>
bool Deque<T, inlineCapacity>::contains(const U& searchValue) const
{
auto endIterator = end();
return std::find(begin(), endIterator, searchValue) != endIterator;
}
template<typename T, size_t inlineCapacity>
inline auto Deque<T, inlineCapacity>::takeFirst() -> T
{
T oldFirst = WTFMove(first());
removeFirst();
return oldFirst;
}
template<typename T, size_t inlineCapacity>
inline auto Deque<T, inlineCapacity>::takeLast() -> T
{
T oldLast = WTFMove(last());
removeLast();
return oldLast;
}
template<typename T, size_t inlineCapacity> template<typename U>
inline void Deque<T, inlineCapacity>::append(U&& value)
{
checkValidity();
expandCapacityIfNeeded();
new (NotNull, std::addressof(m_buffer.buffer()[m_end])) T(std::forward<U>(value));
if (m_end == m_buffer.capacity() - 1)
m_end = 0;
else
++m_end;
checkValidity();
}
template<typename T, size_t inlineCapacity> template<typename U>
inline void Deque<T, inlineCapacity>::prepend(U&& value)
{
checkValidity();
expandCapacityIfNeeded();
if (!m_start)
m_start = m_buffer.capacity() - 1;
else
--m_start;
new (NotNull, std::addressof(m_buffer.buffer()[m_start])) T(std::forward<U>(value));
checkValidity();
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::removeFirst()
{
checkValidity();
invalidateIterators();
ASSERT(!isEmpty());
TypeOperations::destruct(std::addressof(m_buffer.buffer()[m_start]), std::addressof(m_buffer.buffer()[m_start + 1]));
if (m_start == m_buffer.capacity() - 1)
m_start = 0;
else
++m_start;
checkValidity();
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::removeLast()
{
checkValidity();
invalidateIterators();
ASSERT(!isEmpty());
if (!m_end)
m_end = m_buffer.capacity() - 1;
else
--m_end;
TypeOperations::destruct(std::addressof(m_buffer.buffer()[m_end]), std::addressof(m_buffer.buffer()[m_end + 1]));
checkValidity();
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::remove(iterator& it)
{
it.checkValidity();
remove(it.m_index);
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::remove(const_iterator& it)
{
it.checkValidity();
remove(it.m_index);
}
template<typename T, size_t inlineCapacity>
inline void Deque<T, inlineCapacity>::remove(size_t position)
{
if (position == m_end)
return;
checkValidity();
invalidateIterators();
T* buffer = m_buffer.buffer();
TypeOperations::destruct(std::addressof(buffer[position]), std::addressof(buffer[position + 1]));
// Find which segment of the circular buffer contained the remove element, and only move elements in that part.
if (position >= m_start) {
TypeOperations::moveOverlapping(buffer + m_start, buffer + position, buffer + m_start + 1);
m_start = (m_start + 1) % m_buffer.capacity();
} else {
TypeOperations::moveOverlapping(buffer + position + 1, buffer + m_end, buffer + position);
m_end = (m_end - 1 + m_buffer.capacity()) % m_buffer.capacity();
}
checkValidity();
}
template<typename T, size_t inlineCapacity>
template<typename Func>
inline void Deque<T, inlineCapacity>::removeAllMatching(const Func& func)
{
size_t count = size();
while (count--) {
T value = takeFirst();
if (!func(value))
append(WTFMove(value));
}
}
template<typename T, size_t inlineCapacity>
template<typename U, typename Func>
inline void Deque<T, inlineCapacity>::appendAndBubble(U&& value, const Func& func)
{
append(WTFMove(value));
iterator begin = this->begin();
iterator iter = end();
--iter;
while (iter != begin) {
iterator prev = iter;
--prev;
if (!func(*prev))
return;
std::swap(*prev, *iter);
iter = prev;
}
}
template<typename T, size_t inlineCapacity>
template<typename Func>
inline T Deque<T, inlineCapacity>::takeFirst(const Func& func)
{
unsigned count = 0;
unsigned size = this->size();
while (count < size) {
T candidate = takeFirst();
if (func(candidate)) {
while (count--)
prepend(takeLast());
return candidate;
}
count++;
append(WTFMove(candidate));
}
return T();
}
template<typename T, size_t inlineCapacity>
template<typename Func>
inline T Deque<T, inlineCapacity>::takeLast(const Func& func)
{
unsigned count = 0;
unsigned size = this->size();
while (count < size) {
T candidate = takeLast();
if (func(candidate)) {
while (count--)
append(takeFirst());
return candidate;
}
count++;
prepend(WTFMove(candidate));
}
return T();
}
#ifdef NDEBUG
template<typename T, size_t inlineCapacity> inline void DequeIteratorBase<T, inlineCapacity>::checkValidity() const { }
template<typename T, size_t inlineCapacity> inline void DequeIteratorBase<T, inlineCapacity>::checkValidity(const DequeIteratorBase<T, inlineCapacity>&) const { }
template<typename T, size_t inlineCapacity> inline void DequeIteratorBase<T, inlineCapacity>::addToIteratorsList() { }
template<typename T, size_t inlineCapacity> inline void DequeIteratorBase<T, inlineCapacity>::removeFromIteratorsList() { }
#else
template<typename T, size_t inlineCapacity>
void DequeIteratorBase<T, inlineCapacity>::checkValidity() const
{
ASSERT(m_deque);
m_deque->checkIndexValidity(m_index);
}
template<typename T, size_t inlineCapacity>
void DequeIteratorBase<T, inlineCapacity>::checkValidity(const DequeIteratorBase& other) const
{
checkValidity();
other.checkValidity();
ASSERT(m_deque == other.m_deque);
}
template<typename T, size_t inlineCapacity>
void DequeIteratorBase<T, inlineCapacity>::addToIteratorsList()
{
if (!m_deque)
m_next = 0;
else {
m_next = m_deque->m_iterators;
m_deque->m_iterators = this;
if (m_next)
m_next->m_previous = this;
}
m_previous = 0;
}
template<typename T, size_t inlineCapacity>
void DequeIteratorBase<T, inlineCapacity>::removeFromIteratorsList()
{
if (!m_deque) {
ASSERT(!m_next);
ASSERT(!m_previous);
} else {
if (m_next) {
ASSERT(m_next->m_previous == this);
m_next->m_previous = m_previous;
}
if (m_previous) {
ASSERT(m_deque->m_iterators != this);
ASSERT(m_previous->m_next == this);
m_previous->m_next = m_next;
} else {
ASSERT(m_deque->m_iterators == this);
m_deque->m_iterators = m_next;
}
}
m_next = 0;
m_previous = 0;
}
#endif
template<typename T, size_t inlineCapacity>
inline DequeIteratorBase<T, inlineCapacity>::DequeIteratorBase()
: m_deque(0)
{
}
template<typename T, size_t inlineCapacity>
inline DequeIteratorBase<T, inlineCapacity>::DequeIteratorBase(const Deque<T, inlineCapacity>* deque, size_t index)
: m_deque(const_cast<Deque<T, inlineCapacity>*>(deque))
, m_index(index)
{
addToIteratorsList();
checkValidity();
}
template<typename T, size_t inlineCapacity>
inline DequeIteratorBase<T, inlineCapacity>::DequeIteratorBase(const DequeIteratorBase& other)
: m_deque(other.m_deque)
, m_index(other.m_index)
{
addToIteratorsList();
checkValidity();
}
template<typename T, size_t inlineCapacity>
inline DequeIteratorBase<T, inlineCapacity>& DequeIteratorBase<T, inlineCapacity>::operator=(const DequeIteratorBase& other)
{
other.checkValidity();
removeFromIteratorsList();
m_deque = other.m_deque;
m_index = other.m_index;
addToIteratorsList();
checkValidity();
return *this;
}
template<typename T, size_t inlineCapacity>
inline DequeIteratorBase<T, inlineCapacity>::~DequeIteratorBase()
{
#ifndef NDEBUG
removeFromIteratorsList();
m_deque = 0;
#endif
}
template<typename T, size_t inlineCapacity>
inline bool DequeIteratorBase<T, inlineCapacity>::isEqual(const DequeIteratorBase& other) const
{
checkValidity(other);
return m_index == other.m_index;
}
template<typename T, size_t inlineCapacity>
inline void DequeIteratorBase<T, inlineCapacity>::increment()
{
checkValidity();
ASSERT(m_index != m_deque->m_end);
ASSERT(m_deque->m_buffer.capacity());
if (m_index == m_deque->m_buffer.capacity() - 1)
m_index = 0;
else
++m_index;
checkValidity();
}
template<typename T, size_t inlineCapacity>
inline void DequeIteratorBase<T, inlineCapacity>::decrement()
{
checkValidity();
ASSERT(m_index != m_deque->m_start);
ASSERT(m_deque->m_buffer.capacity());
if (!m_index)
m_index = m_deque->m_buffer.capacity() - 1;
else
--m_index;
checkValidity();
}
template<typename T, size_t inlineCapacity>
inline T* DequeIteratorBase<T, inlineCapacity>::after() const
{
checkValidity();
ASSERT(m_index != m_deque->m_end);
return std::addressof(m_deque->m_buffer.buffer()[m_index]);
}
template<typename T, size_t inlineCapacity>
inline T* DequeIteratorBase<T, inlineCapacity>::before() const
{
checkValidity();
ASSERT(m_index != m_deque->m_start);
if (!m_index)
return std::addressof(m_deque->m_buffer.buffer()[m_deque->m_buffer.capacity() - 1]);
return std::addressof(m_deque->m_buffer.buffer()[m_index - 1]);
}
} // namespace WTF
using WTF::Deque;