JavaScriptCore/wtf/Deque.h - platform/external/webkit - Git at Google

 /*
  * Copyright (C) 2007, 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
  * (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 WTF_Deque_h
 #define WTF_Deque_h

 // FIXME: Could move what Vector and Deque share into a separate file.
 // Deque doesn't actually use Vector.

 #include "Vector.h"

 namespace WTF {

     template<typename T> class DequeIteratorBase;
     template<typename T> class DequeIterator;
     template<typename T> class DequeConstIterator;
     template<typename T> class DequeReverseIterator;
     template<typename T> class DequeConstReverseIterator;

     template<typename T>
     class Deque {
     public:
         typedef DequeIterator<T> iterator;
         typedef DequeConstIterator<T> const_iterator;
         typedef DequeReverseIterator<T> reverse_iterator;
         typedef DequeConstReverseIterator<T> const_reverse_iterator;

         Deque();
         Deque(const Deque<T>&);
         Deque& operator=(const Deque<T>&);
         ~Deque();

         void swap(Deque<T>&);

         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(this, m_end); }
         reverse_iterator rend() { return reverse_iterator(this, m_start); }
         const_reverse_iterator rbegin() const { return const_reverse_iterator(this, m_end); }
         const_reverse_iterator rend() const { return const_reverse_iterator(this, m_start); }

         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]; }

         template<typename U> void append(const U&);
         template<typename U> void prepend(const U&);
         void removeFirst();

         void clear();

     private:
         friend class DequeIteratorBase<T>;

         typedef VectorBuffer<T, 0> Buffer;
         typedef VectorTypeOperations<T> TypeOperations;
         typedef DequeIteratorBase<T> IteratorBase;

         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>
     class DequeIteratorBase {
     private:
         typedef DequeIteratorBase<T> Base;

     protected:
         DequeIteratorBase();
         DequeIteratorBase(const Deque<T>*, size_t);
         DequeIteratorBase(const Base&);
         Base& operator=(const Base&);
         ~DequeIteratorBase();

         void assign(const Base& other) { *this = other; }

         void increment();
         void decrement();

         T* before() const;
         T* after() const;

         bool isEqual(const Base&) const;

     private:
         void addToIteratorsList();
         void checkValidity() const;
         void checkValidity(const Base&) const;

         Deque<T>* m_deque;
         size_t m_index;

         friend class Deque<T>;

 #ifndef NDEBUG
         mutable DequeIteratorBase* m_next;
         mutable DequeIteratorBase* m_previous;
 #endif
     };

     template<typename T>
     class DequeIterator : public DequeIteratorBase<T> {
     private:
         typedef DequeIteratorBase<T> Base;
         typedef DequeIterator<T> Iterator;

     public:
         DequeIterator(Deque<T>* 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>
     class DequeConstIterator : public DequeIteratorBase<T> {
     private:
         typedef DequeIteratorBase<T> Base;
         typedef DequeConstIterator<T> Iterator;
         typedef DequeIterator<T> NonConstIterator;

     public:
         DequeConstIterator(const Deque<T>* 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
     };

     template<typename T>
     class DequeReverseIterator : public DequeIteratorBase<T> {
     private:
         typedef DequeIteratorBase<T> Base;
         typedef DequeReverseIterator<T> Iterator;

     public:
         DequeReverseIterator(const Deque<T>* deque, size_t index) : Base(deque, index) { }

         DequeReverseIterator(const Iterator& other) : Base(other) { }
         DequeReverseIterator& operator=(const Iterator& other) { Base::assign(other); return *this; }

         T& operator*() const { return *Base::before(); }
         T* operator->() const { return Base::before(); }

         bool operator==(const Iterator& other) const { return Base::isEqual(other); }
         bool operator!=(const Iterator& other) const { return !Base::isEqual(other); }

         Iterator& operator++() { Base::decrement(); return *this; }
         // postfix ++ intentionally omitted
         Iterator& operator--() { Base::increment(); return *this; }
         // postfix -- intentionally omitted
     };

     template<typename T>
     class DequeConstReverseIterator : public DequeIteratorBase<T> {
     private:
         typedef DequeIteratorBase<T> Base;
         typedef DequeConstReverseIterator<T> Iterator;
         typedef DequeReverseIterator<T> NonConstIterator;

     public:
         DequeConstReverseIterator(const Deque<T>* deque, size_t index) : Base(deque, index) { }

         DequeConstReverseIterator(const Iterator& other) : Base(other) { }
         DequeConstReverseIterator(const NonConstIterator& other) : Base(other) { }
         DequeConstReverseIterator& operator=(const Iterator& other) { Base::assign(other); return *this; }
         DequeConstReverseIterator& operator=(const NonConstIterator& other) { Base::assign(other); return *this; }

         const T& operator*() const { return *Base::before(); }
         const T* operator->() const { return Base::before(); }

         bool operator==(const Iterator& other) const { return Base::isEqual(other); }
         bool operator!=(const Iterator& other) const { return !Base::isEqual(other); }

         Iterator& operator++() { Base::decrement(); return *this; }
         // postfix ++ intentionally omitted
         Iterator& operator--() { Base::increment(); return *this; }
         // postfix -- intentionally omitted
     };

 #ifdef NDEBUG
     template<typename T> inline void Deque<T>::checkValidity() const { }
     template<typename T> inline void Deque<T>::checkIndexValidity(size_t) const { }
     template<typename T> inline void Deque<T>::invalidateIterators() { }
 #else
     template<typename T>
     void Deque<T>::checkValidity() const
     {
         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>
     void Deque<T>::checkIndexValidity(size_t index) const
     {
         ASSERT(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>
     void Deque<T>::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>
     inline Deque<T>::Deque()
         : m_start(0)
         , m_end(0)
 #ifndef NDEBUG
         , m_iterators(0)
 #endif
     {
         checkValidity();
     }

     template<typename T>
     inline Deque<T>::Deque(const Deque<T>& 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>
     void deleteAllValues(const Deque<T>& collection)
     {
         typedef typename Deque<T>::const_iterator iterator;
         iterator end = collection.end();
         for (iterator it = collection.begin(); it != end; ++it)
             delete *it;
     }

     template<typename T>
     inline Deque<T>& Deque<T>::operator=(const Deque<T>& other)
     {
         Deque<T> copy(other);
         swap(copy);
         return *this;
     }

     template<typename T>
     inline void Deque<T>::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>
     inline Deque<T>::~Deque()
     {
         checkValidity();
         invalidateIterators();
         destroyAll();
     }

     template <typename T>
     inline void Deque<T>::swap(Deque<T>& 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);
         checkValidity();
         other.checkValidity();
     }

     template <typename T>
     inline void Deque<T>::clear()
     {
         checkValidity();
         invalidateIterators();
         destroyAll();
         m_start = 0;
         m_end = 0;
         checkValidity();
     }

     template<typename T>
     inline void Deque<T>::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>
     void Deque<T>::expandCapacity()
     {
         checkValidity();
         size_t oldCapacity = m_buffer.capacity();
         size_t newCapacity = max(static_cast<size_t>(16), oldCapacity + oldCapacity / 4 + 1);
         T* oldBuffer = m_buffer.buffer();
         m_buffer.allocateBuffer(newCapacity);
         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 = newCapacity - (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> template<typename U>
     inline void Deque<T>::append(const U& value)
     {
         checkValidity();
         expandCapacityIfNeeded();
         new (&m_buffer.buffer()[m_end]) T(value);
         if (m_end == m_buffer.capacity() - 1)
             m_end = 0;
         else
             ++m_end;
         checkValidity();
     }

     template<typename T> template<typename U>
     inline void Deque<T>::prepend(const U& value)
     {
         checkValidity();
         expandCapacityIfNeeded();
         if (!m_start)
             m_start = m_buffer.capacity() - 1;
         else
             --m_start;
         new (&m_buffer.buffer()[m_start]) T(value);
         checkValidity();
     }

     template<typename T>
     inline void Deque<T>::removeFirst()
     {
         checkValidity();
         invalidateIterators();
         ASSERT(!isEmpty());
         TypeOperations::destruct(&m_buffer.buffer()[m_start], &m_buffer.buffer()[m_start + 1]);
         if (m_start == m_buffer.capacity() - 1)
             m_start = 0;
         else
             ++m_start;
         checkValidity();
     }

 #ifdef NDEBUG
     template<typename T> inline void DequeIteratorBase<T>::checkValidity() const { }
     template<typename T> inline void DequeIteratorBase<T>::checkValidity(const DequeIteratorBase<T>&) const { }
     template<typename T> inline void DequeIteratorBase<T>::addToIteratorsList() { }
 #else
     template<typename T>
     void DequeIteratorBase<T>::checkValidity() const
     {
         ASSERT(m_deque);
         m_deque->checkIndexValidity(m_index);
     }

     template<typename T>
     void DequeIteratorBase<T>::checkValidity(const Base& other) const
     {
         checkValidity();
         other.checkValidity();
         ASSERT(m_deque == other.m_deque);
     }

     template<typename T>
     void DequeIteratorBase<T>::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;
     }
 #endif

     template<typename T>
     inline DequeIteratorBase<T>::DequeIteratorBase()
         : m_deque(0)
     {
     }

     template<typename T>
     inline DequeIteratorBase<T>::DequeIteratorBase(const Deque<T>* deque, size_t index)
         : m_deque(const_cast<Deque<T>*>(deque))
         , m_index(index)
     {
         addToIteratorsList();
         checkValidity();
     }

     template<typename T>
     inline DequeIteratorBase<T>::DequeIteratorBase(const Base& other)
         : m_deque(other.m_deque)
         , m_index(other.m_index)
     {
         addToIteratorsList();
         checkValidity();
     }

     template<typename T>
     inline DequeIteratorBase<T>::~DequeIteratorBase()
     {
 #ifndef NDEBUG
         // Delete iterator from doubly-linked list of iterators.
         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_deque = 0;
         m_next = 0;
         m_previous = 0;
 #endif
     }

     template<typename T>
     inline bool DequeIteratorBase<T>::isEqual(const Base& other) const
     {
         checkValidity(other);
         return m_index == other.m_index;
     }

     template<typename T>
     inline void DequeIteratorBase<T>::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>
     inline void DequeIteratorBase<T>::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>
     inline T* DequeIteratorBase<T>::after() const
     {
         checkValidity();
         ASSERT(m_index != m_deque->m_end);
         return &m_deque->m_buffer.buffer()[m_index];
     }

     template<typename T>
     inline T* DequeIteratorBase<T>::before() const
     {
         checkValidity();
         ASSERT(m_index != m_deque->m_start);
         if (!m_index)
             return &m_deque->m_buffer.buffer()[m_deque->m_buffer.capacity() - 1];
         return &m_deque->m_buffer.buffer()[m_index - 1];
     }

 } // namespace WTF

 using WTF::Deque;

 #endif // WTF_Deque_h
	/*
	* Copyright (C) 2007, 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
	* (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 WTF_Deque_h
	#define WTF_Deque_h

	// FIXME: Could move what Vector and Deque share into a separate file.
	// Deque doesn't actually use Vector.

	#include "Vector.h"

	namespace WTF {

	template<typename T> class DequeIteratorBase;
	template<typename T> class DequeIterator;
	template<typename T> class DequeConstIterator;
	template<typename T> class DequeReverseIterator;
	template<typename T> class DequeConstReverseIterator;

	template<typename T>
	class Deque {
	public:
	typedef DequeIterator<T> iterator;
	typedef DequeConstIterator<T> const_iterator;
	typedef DequeReverseIterator<T> reverse_iterator;
	typedef DequeConstReverseIterator<T> const_reverse_iterator;

	Deque();
	Deque(const Deque<T>&);
	Deque& operator=(const Deque<T>&);
	~Deque();

	void swap(Deque<T>&);

	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(this, m_end); }
	reverse_iterator rend() { return reverse_iterator(this, m_start); }
	const_reverse_iterator rbegin() const { return const_reverse_iterator(this, m_end); }
	const_reverse_iterator rend() const { return const_reverse_iterator(this, m_start); }

	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]; }

	template<typename U> void append(const U&);
	template<typename U> void prepend(const U&);
	void removeFirst();

	void clear();

	private:
	friend class DequeIteratorBase<T>;

	typedef VectorBuffer<T, 0> Buffer;
	typedef VectorTypeOperations<T> TypeOperations;
	typedef DequeIteratorBase<T> IteratorBase;

	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>
	class DequeIteratorBase {
	private:
	typedef DequeIteratorBase<T> Base;

	protected:
	DequeIteratorBase();
	DequeIteratorBase(const Deque<T>*, size_t);
	DequeIteratorBase(const Base&);
	Base& operator=(const Base&);
	~DequeIteratorBase();

	void assign(const Base& other) { *this = other; }

	void increment();
	void decrement();

	T* before() const;
	T* after() const;

	bool isEqual(const Base&) const;

	private:
	void addToIteratorsList();
	void checkValidity() const;
	void checkValidity(const Base&) const;

	Deque<T>* m_deque;
	size_t m_index;

	friend class Deque<T>;

	#ifndef NDEBUG
	mutable DequeIteratorBase* m_next;
	mutable DequeIteratorBase* m_previous;
	#endif
	};

	template<typename T>
	class DequeIterator : public DequeIteratorBase<T> {
	private:
	typedef DequeIteratorBase<T> Base;
	typedef DequeIterator<T> Iterator;

	public:
	DequeIterator(Deque<T>* 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>
	class DequeConstIterator : public DequeIteratorBase<T> {
	private:
	typedef DequeIteratorBase<T> Base;
	typedef DequeConstIterator<T> Iterator;
	typedef DequeIterator<T> NonConstIterator;

	public:
	DequeConstIterator(const Deque<T>* 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
	};

	template<typename T>
	class DequeReverseIterator : public DequeIteratorBase<T> {
	private:
	typedef DequeIteratorBase<T> Base;
	typedef DequeReverseIterator<T> Iterator;

	public:
	DequeReverseIterator(const Deque<T>* deque, size_t index) : Base(deque, index) { }

	DequeReverseIterator(const Iterator& other) : Base(other) { }
	DequeReverseIterator& operator=(const Iterator& other) { Base::assign(other); return *this; }

	T& operator() const { return Base::before(); }
	T* operator->() const { return Base::before(); }

	bool operator==(const Iterator& other) const { return Base::isEqual(other); }
	bool operator!=(const Iterator& other) const { return !Base::isEqual(other); }

	Iterator& operator++() { Base::decrement(); return *this; }
	// postfix ++ intentionally omitted
	Iterator& operator--() { Base::increment(); return *this; }
	// postfix -- intentionally omitted
	};

	template<typename T>
	class DequeConstReverseIterator : public DequeIteratorBase<T> {
	private:
	typedef DequeIteratorBase<T> Base;
	typedef DequeConstReverseIterator<T> Iterator;
	typedef DequeReverseIterator<T> NonConstIterator;

	public:
	DequeConstReverseIterator(const Deque<T>* deque, size_t index) : Base(deque, index) { }

	DequeConstReverseIterator(const Iterator& other) : Base(other) { }
	DequeConstReverseIterator(const NonConstIterator& other) : Base(other) { }
	DequeConstReverseIterator& operator=(const Iterator& other) { Base::assign(other); return *this; }
	DequeConstReverseIterator& operator=(const NonConstIterator& other) { Base::assign(other); return *this; }

	const T& operator() const { return Base::before(); }
	const T* operator->() const { return Base::before(); }

	bool operator==(const Iterator& other) const { return Base::isEqual(other); }
	bool operator!=(const Iterator& other) const { return !Base::isEqual(other); }

	Iterator& operator++() { Base::decrement(); return *this; }
	// postfix ++ intentionally omitted
	Iterator& operator--() { Base::increment(); return *this; }
	// postfix -- intentionally omitted
	};

	#ifdef NDEBUG
	template<typename T> inline void Deque<T>::checkValidity() const { }
	template<typename T> inline void Deque<T>::checkIndexValidity(size_t) const { }
	template<typename T> inline void Deque<T>::invalidateIterators() { }
	#else
	template<typename T>
	void Deque<T>::checkValidity() const
	{
	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>
	void Deque<T>::checkIndexValidity(size_t index) const
	{
	ASSERT(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>
	void Deque<T>::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>
	inline Deque<T>::Deque()
	: m_start(0)
	, m_end(0)
	#ifndef NDEBUG
	, m_iterators(0)
	#endif
	{
	checkValidity();
	}

	template<typename T>
	inline Deque<T>::Deque(const Deque<T>& 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>
	void deleteAllValues(const Deque<T>& collection)
	{
	typedef typename Deque<T>::const_iterator iterator;
	iterator end = collection.end();
	for (iterator it = collection.begin(); it != end; ++it)
	delete *it;
	}

	template<typename T>
	inline Deque<T>& Deque<T>::operator=(const Deque<T>& other)
	{
	Deque<T> copy(other);
	swap(copy);
	return *this;
	}

	template<typename T>
	inline void Deque<T>::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>
	inline Deque<T>::~Deque()
	{
	checkValidity();
	invalidateIterators();
	destroyAll();
	}

	template <typename T>
	inline void Deque<T>::swap(Deque<T>& 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);
	checkValidity();
	other.checkValidity();
	}

	template <typename T>
	inline void Deque<T>::clear()
	{
	checkValidity();
	invalidateIterators();
	destroyAll();
	m_start = 0;
	m_end = 0;
	checkValidity();
	}

	template<typename T>
	inline void Deque<T>::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>
	void Deque<T>::expandCapacity()
	{
	checkValidity();
	size_t oldCapacity = m_buffer.capacity();
	size_t newCapacity = max(static_cast<size_t>(16), oldCapacity + oldCapacity / 4 + 1);
	T* oldBuffer = m_buffer.buffer();
	m_buffer.allocateBuffer(newCapacity);
	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 = newCapacity - (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> template<typename U>
	inline void Deque<T>::append(const U& value)
	{
	checkValidity();
	expandCapacityIfNeeded();
	new (&m_buffer.buffer()[m_end]) T(value);
	if (m_end == m_buffer.capacity() - 1)
	m_end = 0;
	else
	++m_end;
	checkValidity();
	}

	template<typename T> template<typename U>
	inline void Deque<T>::prepend(const U& value)
	{
	checkValidity();
	expandCapacityIfNeeded();
	if (!m_start)
	m_start = m_buffer.capacity() - 1;
	else
	--m_start;
	new (&m_buffer.buffer()[m_start]) T(value);
	checkValidity();
	}

	template<typename T>
	inline void Deque<T>::removeFirst()
	{
	checkValidity();
	invalidateIterators();
	ASSERT(!isEmpty());
	TypeOperations::destruct(&m_buffer.buffer()[m_start], &m_buffer.buffer()[m_start + 1]);
	if (m_start == m_buffer.capacity() - 1)
	m_start = 0;
	else
	++m_start;
	checkValidity();
	}

	#ifdef NDEBUG
	template<typename T> inline void DequeIteratorBase<T>::checkValidity() const { }
	template<typename T> inline void DequeIteratorBase<T>::checkValidity(const DequeIteratorBase<T>&) const { }
	template<typename T> inline void DequeIteratorBase<T>::addToIteratorsList() { }
	#else
	template<typename T>
	void DequeIteratorBase<T>::checkValidity() const
	{
	ASSERT(m_deque);
	m_deque->checkIndexValidity(m_index);
	}

	template<typename T>
	void DequeIteratorBase<T>::checkValidity(const Base& other) const
	{
	checkValidity();
	other.checkValidity();
	ASSERT(m_deque == other.m_deque);
	}

	template<typename T>
	void DequeIteratorBase<T>::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;
	}
	#endif

	template<typename T>
	inline DequeIteratorBase<T>::DequeIteratorBase()
	: m_deque(0)
	{
	}

	template<typename T>
	inline DequeIteratorBase<T>::DequeIteratorBase(const Deque<T>* deque, size_t index)
	: m_deque(const_cast<Deque<T>*>(deque))
	, m_index(index)
	{
	addToIteratorsList();
	checkValidity();
	}

	template<typename T>
	inline DequeIteratorBase<T>::DequeIteratorBase(const Base& other)
	: m_deque(other.m_deque)
	, m_index(other.m_index)
	{
	addToIteratorsList();
	checkValidity();
	}

	template<typename T>
	inline DequeIteratorBase<T>::~DequeIteratorBase()
	{
	#ifndef NDEBUG
	// Delete iterator from doubly-linked list of iterators.
	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_deque = 0;
	m_next = 0;
	m_previous = 0;
	#endif
	}

	template<typename T>
	inline bool DequeIteratorBase<T>::isEqual(const Base& other) const
	{
	checkValidity(other);
	return m_index == other.m_index;
	}

	template<typename T>
	inline void DequeIteratorBase<T>::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>
	inline void DequeIteratorBase<T>::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>
	inline T* DequeIteratorBase<T>::after() const
	{
	checkValidity();
	ASSERT(m_index != m_deque->m_end);
	return &m_deque->m_buffer.buffer()[m_index];
	}

	template<typename T>
	inline T* DequeIteratorBase<T>::before() const
	{
	checkValidity();
	ASSERT(m_index != m_deque->m_start);
	if (!m_index)
	return &m_deque->m_buffer.buffer()[m_deque->m_buffer.capacity() - 1];
	return &m_deque->m_buffer.buffer()[m_index - 1];
	}

	} // namespace WTF

	using WTF::Deque;

	#endif // WTF_Deque_h