/*

 * Copyright (C) 2007, 2008 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 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 FastAllocBase {

    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]; }

        T takeFirst();

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

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

        void removeFirst();

        void remove(iterator&);

        void remove(const_iterator&);

        void clear();

        template<typename Predicate>

        iterator findIf(Predicate&);

    private:

        friend class DequeIteratorBase<T>;

        typedef VectorBuffer<T, 0> Buffer;

        typedef VectorTypeOperations<T> TypeOperations;

        typedef DequeIteratorBase<T> 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>

    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 removeFromIteratorsList();

        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>

    template<typename Predicate>

    inline DequeIterator<T> Deque<T>::findIf(Predicate& predicate)

    {

        iterator end_iterator = end();

        for (iterator it = begin(); it != end_iterator; ++it) {

            if (predicate(*it))

                return it;

        }

        return end_iterator;

    }

    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>

    inline T Deque<T>::takeFirst()

    {

        T oldFirst = first();

        removeFirst();

        return oldFirst;

    }

    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();

    }

    template<typename T>

    inline void Deque<T>::remove(iterator& it)

    {

        it.checkValidity();

        remove(it.m_index);

    }

    template<typename T>

    inline void Deque<T>::remove(const_iterator& it)

    {

        it.checkValidity();

        remove(it.m_index);

    }

    template<typename T>

    inline void Deque<T>::remove(size_t position)

    {

        if (position == m_end)

            return;

        checkValidity();

        invalidateIterators();

        T* buffer = m_buffer.buffer();

        TypeOperations::destruct(&buffer[position], &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();

    }

#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() { }

    template<typename T> inline void DequeIteratorBase<T>::removeFromIteratorsList() { }

#else

    template<typename T>

    void DequeIteratorBase<T>::checkValidity() const

    {

        ASSERT(m_deque);

        m_deque->checkIndexValidity(m_index);

    }