// -*- C++ -*-
/***************************************************************************
 *
 * <deque> - definition of the C++ Standard Library deque class template
 *
 * $Id$
 *
 ***************************************************************************
 *
 * Licensed to the Apache Software  Foundation (ASF) under one or more
 * contributor  license agreements.  See  the NOTICE  file distributed
 * with  this  work  for  additional information  regarding  copyright
 * ownership.   The ASF  licenses this  file to  you under  the Apache
 * License, Version  2.0 (the  "License"); you may  not use  this file
 * except in  compliance with the License.   You may obtain  a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the  License is distributed on an  "AS IS" BASIS,
 * WITHOUT  WARRANTIES OR CONDITIONS  OF ANY  KIND, either  express or
 * implied.   See  the License  for  the  specific language  governing
 * permissions and limitations under the License.
 *
 * Copyright 1994-2006 Rogue Wave Software.
 *
 ***************************************************************************
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 **************************************************************************/

#ifndef _RWSTD_DEQUE_INCLUDED
#define _RWSTD_DEQUE_INCLUDED


#include <rw/_algobase.h>
#include <rw/_allocator.h>
#include <rw/_iterator.h>
#include <rw/_error.h>
#include <rw/_select.h>
#include <rw/_defs.h>


_RWSTD_NAMESPACE (std) {

_EXPORT
template <class _TypeT, class _Allocator = allocator<_TypeT> >
class deque;

#ifdef _RWSTD_NO_MEMBER_TEMPLATES

// declarations of non-member function templates implementing
// the functionality of deque member function templates

_EXPORT
template <class _TypeT, class _Allocator, class _InputIter>
void __rw_assign_range (deque<_TypeT, _Allocator>*,
                        _InputIter, _InputIter, input_iterator_tag);

_EXPORT
template <class _TypeT, class _Allocator, class _FwdIter>
void __rw_assign_range (deque<_TypeT, _Allocator>*,
                        _FwdIter, _FwdIter, forward_iterator_tag);

_EXPORT
template <class _TypeT, class _Allocator, class _DequeIter, class _InputIter>
void __rw_insert_range (deque<_TypeT, _Allocator>*, _DequeIter,
                        _InputIter, _InputIter, input_iterator_tag);

_EXPORT
template <class _TypeT, class _Allocator, class _DequeIter, class _BidirIter>
void __rw_insert_range (deque<_TypeT, _Allocator>*, _DequeIter,
                        _BidirIter, _BidirIter, bidirectional_iterator_tag);

#endif   // _RWSTD_NO_MEMBER_TEMPLATES


template <class _TypeT, class _DiffT, class _Pointer,
          class _Reference, class _Allocator>
class __rw_deque_iter
    : public iterator <random_access_iterator_tag, _TypeT, _DiffT,
                       _Pointer, _Reference>
{
    typedef iterator <bidirectional_iterator_tag, _TypeT, _DiffT,
                      _Pointer, _Reference>           _C_iter_base;
public:

    typedef _Allocator                               allocator_type;
    typedef _TYPENAME allocator_type::size_type      size_type;
    typedef _TYPENAME _C_iter_base::value_type       value_type;
    typedef _TYPENAME _C_iter_base::difference_type  difference_type;
    typedef _TYPENAME _C_iter_base::pointer          pointer;
    typedef _TYPENAME _C_iter_base::reference        reference;

    typedef random_access_iterator_tag               iterator_category;
    
    typedef __rw_deque_iter<value_type, difference_type,
                            value_type*, value_type&, allocator_type>
    _C_mutable_iter;

    typedef _RWSTD_REBIND (allocator_type, value_type*) _C_node_alloc_type;
    typedef _TYPENAME _C_node_alloc_type::pointer       _C_node_pointer;

    
    static size_type _C_bufsize () {
        // deque only uses __rw_new_capacity to retrieve the minimum
        // allocation amount; this may be specialized to provide a
        // customized minimum amount
        typedef deque<_TypeT, _Allocator> _RWDeque;
        return _RWSTD_NEW_CAPACITY (_RWDeque, (const _RWDeque*)0, 0);
    }
    
#ifdef _RWSTDDEBUG

    __rw_deque_iter (): _C_cur (), _C_node () { /* invalid */ }

    ~__rw_deque_iter () {
        _C_cur  = pointer ();
        _C_node = _C_node_pointer ();   // invalidate
    }

#else   // if !defined (_RWSTDDEBUG)

    __rw_deque_iter () { /* uninitialized */ }

#endif   // _RWSTDDEBUG


    // dummy first argument used to easily switch between
    // iterators with and without support for debugging
    __rw_deque_iter (pointer __cur, _C_node_pointer __node)
        : _C_cur (__cur), _C_node (__node) { }

    // no copy ctor other than the one below defined; will use
    // a compiler generated one if __rw_deque_iter != _C_mutable_iter
    __rw_deque_iter (const _C_mutable_iter &__rhs)
        : _C_cur (__rhs._C_cur),
          _C_node (__rhs._C_node) { }
    
    __rw_deque_iter& operator++ ();
    
    __rw_deque_iter& operator-- ();
    
    __rw_deque_iter operator++ (int) {
        __rw_deque_iter __tmp (*this);
        return ++*this, __tmp;
    }

    __rw_deque_iter operator-- (int) {
        __rw_deque_iter __tmp (*this);
        return --*this, __tmp;
    }

    __rw_deque_iter& operator+= (difference_type);
    
    __rw_deque_iter& operator-= (difference_type __n) {
        return *this += -__n;
    }

    __rw_deque_iter operator+ (difference_type __n) const {
        return __rw_deque_iter (*this) += __n;
    }

    __rw_deque_iter operator- (difference_type __n) const {
        return __rw_deque_iter (*this) -= __n;
    }

    reference operator* () const {
        return *_C_cur;
    }

    _RWSTD_OPERATOR_ARROW (pointer operator-> () const);
    
    reference operator[] (difference_type __n) const {
        return *(*this + __n);
    }

    // `cur' points at the curent element or is null (for the end iterator)
    // `node' points to the array containing the element or &cur (for end)
    pointer         _C_cur;
    _C_node_pointer _C_node;
};


template <class _TypeT, class _DiffT, class _Pointer,
          class _Reference, class _Allocator>
inline __rw_deque_iter<_TypeT, _DiffT, _Pointer, _Reference, _Allocator>&
__rw_deque_iter<_TypeT, _DiffT, _Pointer, _Reference, _Allocator>::
operator++ ()
{
    _RWSTD_ASSERT (pointer () != _C_cur);
    _RWSTD_ASSERT (_C_node_pointer () != _C_node);

    if (++_C_cur == *_C_node + _C_bufsize ())
        _C_cur = *++_C_node;

    return *this;
}


template <class _TypeT, class _DiffT, class _Pointer,
          class _Reference, class _Allocator>
inline __rw_deque_iter<_TypeT, _DiffT, _Pointer, _Reference, _Allocator>&
__rw_deque_iter<_TypeT, _DiffT, _Pointer, _Reference, _Allocator>::
operator-- ()
{
    _RWSTD_ASSERT (_C_node_pointer () != _C_node);

    if (_C_cur == *_C_node)
        _C_cur = *--_C_node + _C_bufsize ();

    --_C_cur;

    return *this;
}


template <class _TypeT, class _DiffT, class _Pointer,
          class _Reference, class _Allocator>
inline __rw_deque_iter<_TypeT, _DiffT, _Pointer, _Reference, _Allocator>&
__rw_deque_iter<_TypeT, _DiffT, _Pointer, _Reference, _Allocator>::
operator+= (difference_type __n)
{
    _RWSTD_ASSERT (_C_node_pointer () != _C_node);

    const size_type __bufsize = _C_bufsize ();

    const difference_type __offset = __n + (_C_cur - *_C_node);

    if (__bufsize <= size_type (__offset)) {

        _RWSTD_ASSERT (__n != 0);

        const difference_type __jump = __offset >= 0 ? __offset / __bufsize
            : -difference_type ((__bufsize - __offset - 1) / __bufsize);

        _C_node += __jump;
        _C_cur   = *_C_node + (__offset - __jump * __bufsize);
    }
    else
        _C_cur += __n;

    _RWSTD_ASSERT (size_type (_C_cur - *_C_node) <= __bufsize);

    return *this;
}


// for symmetry
template <class _TypeT, class _DiffT, class _Ptr, class _Ref, class _Alloc>
inline __rw_deque_iter<_TypeT, _DiffT, _Ptr, _Ref, _Alloc>
operator+ (_DiffT                                                     __lhs,
           const __rw_deque_iter<_TypeT, _DiffT, _Ptr, _Ref, _Alloc> &__rhs)
{
    return __rhs + __lhs;
}


#define _RWSTD_DEQUE_ITER(n) \
        __rw_deque_iter<_TypeT, _DiffT, _Ptr##n, _Ref##n, _Alloc>


template <class _TypeT, class _DiffT,
          class _Ptr1, class _Ref1, class _Ptr2, class _Ref2, class _Alloc>
inline _DiffT
operator- (const _RWSTD_DEQUE_ITER(1) &__x, const _RWSTD_DEQUE_ITER(2) &__y)
{
    // _RWSTD_ASSERT_RANGE (__x, __y);

    const _DiffT __bufsize = _DiffT (__x._C_bufsize ());

    return _DiffT (  __bufsize * (__x._C_node - __y._C_node - 1)
                   + (__x._C_cur - *__x._C_node)
                   + (*__y._C_node + __bufsize - __y._C_cur));
}


template <class _TypeT, class _DiffT,
          class _Ptr1, class _Ref1, class _Ptr2, class _Ref2, class _Alloc>
inline bool
operator== (const _RWSTD_DEQUE_ITER(1) &__x, const _RWSTD_DEQUE_ITER(2) &__y)
{
    return 0 == __x - __y;
}


template <class _TypeT, class _DiffT,
          class _Ptr1, class _Ref1, class _Ptr2, class _Ref2, class _Alloc>
inline bool
operator< (const _RWSTD_DEQUE_ITER(1) &__x, const _RWSTD_DEQUE_ITER(2) &__y)
{
    return __x - __y < 0;
}


template <class _TypeT, class _DiffT,
          class _Ptr1, class _Ref1, class _Ptr2, class _Ref2, class _Alloc>
inline bool
operator!= (const _RWSTD_DEQUE_ITER(1) &__x, const _RWSTD_DEQUE_ITER(2) &__y)
{
    return !(__x == __y);
}


template <class _TypeT, class _DiffT,
          class _Ptr1, class _Ref1, class _Ptr2, class _Ref2, class _Alloc>
inline bool
operator<= (const _RWSTD_DEQUE_ITER(1) &__x, const _RWSTD_DEQUE_ITER(2) &__y)
{
    return !(__y < __x);
}

template <class _TypeT, class _DiffT,
          class _Ptr1, class _Ref1, class _Ptr2, class _Ref2, class _Alloc>
inline bool
operator>= (const _RWSTD_DEQUE_ITER(1) &__x, const _RWSTD_DEQUE_ITER(2) &__y)
{
    return !(__x < __y);
}

template <class _TypeT, class _DiffT,
          class _Ptr1, class _Ref1, class _Ptr2, class _Ref2, class _Alloc>
inline bool
operator> (const _RWSTD_DEQUE_ITER(1) &__x, const _RWSTD_DEQUE_ITER(2) &__y)
{
    return __y < __x;
}


#undef _RWSTD_DEQUE_ITER


_EXPORT
template <class _TypeT, class _Allocator>
class deque: private _Allocator
{
public:

    typedef _TypeT                                    value_type;
    typedef _Allocator                                allocator_type;
    typedef _TYPENAME allocator_type::size_type       size_type;
    typedef _TYPENAME allocator_type::difference_type difference_type;
    typedef _TYPENAME allocator_type::pointer         pointer;
    typedef _TYPENAME allocator_type::const_pointer   const_pointer;
    typedef _TYPENAME allocator_type::reference       reference;
    typedef _TYPENAME allocator_type::const_reference const_reference;

    typedef _RWSTD_ALLOC_TYPE (allocator_type, value_type) _C_value_alloc_type;

    // following two typedefs are used for convenience with debug iters
    typedef __rw_deque_iter<value_type, difference_type, pointer,
                            reference, allocator_type>         _C_deque_iter; 

    typedef __rw_deque_iter<value_type, difference_type, const_pointer,
                            const_reference, allocator_type>   _C_deque_citer;

    typedef _RWSTD_REBIND (allocator_type, value_type*) _C_node_alloc_type;

    typedef _TYPENAME _C_node_alloc_type::pointer       _C_node_pointer;

#ifndef _RWSTD_NO_DEBUG_ITER

    typedef _RW::__rw_debug_iter<deque, _C_deque_iter, _C_deque_iter>
        iterator;
    
    typedef _RW::__rw_debug_iter<deque, _C_deque_citer, _C_deque_iter>
        const_iterator;
    
    iterator _C_make_iter (const _C_deque_iter &__iter) { 
        return iterator (*this, __iter);
    }

    const_iterator _C_make_iter (const _C_deque_citer &__citer) const {
        return const_iterator (*this, __citer);
    }

#else   // if defined (_RWSTD_NO_DEBUG_ITER)
    
    typedef _C_deque_iter  iterator;
    typedef _C_deque_citer const_iterator;
    
    iterator _C_make_iter (const _C_deque_iter &__iter) {
        return __iter;
    }

    const_iterator _C_make_iter (const _C_deque_citer &__citer) const {
        return __citer;
    }

#endif   // _RWSTD_NO_DEBUG_ITER

    size_type _C_vecsize (size_type __nodes) const {
        return _RWSTD_NEW_CAPACITY (deque, this, __nodes);
    }

    static size_type _C_bufsize () {
        return _C_deque_iter::_C_bufsize ();
    }

#ifndef _RWSTD_NO_CLASS_PARTIAL_SPEC 

    typedef _STD::reverse_iterator<const_iterator> const_reverse_iterator;
    typedef _STD::reverse_iterator<iterator>       reverse_iterator;

#else   // if defined (_RWSTD_NO_CLASS_PARTIAL_SPEC)

    typedef _STD::reverse_iterator<const_iterator, random_access_iterator_tag,
                                   value_type, const_reference, const_pointer,
                                   difference_type>
        const_reverse_iterator;

    typedef _STD::reverse_iterator<iterator, random_access_iterator_tag,
                                   value_type, reference, pointer,
                                   difference_type>
        reverse_iterator;

#endif   // _RWSTD_NO_CLASS_PARTIAL_SPEC 

    _EXPLICIT
    deque (const allocator_type &__alloc = allocator_type ())
      : allocator_type (__alloc) {
        _C_init ();
    }

    _EXPLICIT
    deque (size_type __n, const_reference __x = value_type (), 
           const allocator_type &__alloc = allocator_type ())
        : allocator_type (__alloc) {
        _C_init ();
        assign (__n, __x);
    }

    template <class _InputIter>
    deque (_InputIter __first, _InputIter __last,
           const allocator_type &__alloc = allocator_type ())
        : allocator_type (__alloc) {
        _C_init ();
        assign (__first, __last);
    }

    deque (const deque &__rhs)
        : allocator_type (__rhs.get_allocator ()) {
        _C_init ();
        assign (__rhs.begin (), __rhs.end ());
    }

    ~deque () {
        clear ();
    }

    deque& operator= (const deque&);

    template <class _InputIter>
    void assign (_InputIter __first, _InputIter __last) {
        // dispatch either to a range assign or to an assign with repetition
        _C_assign (__first, __last, _RWSTD_DISPATCH (_InputIter));
    }

    void assign (size_type __n, const_reference __x) {
        _C_assign_n (__n, __x);
    }

    allocator_type get_allocator () const {
        return *this;
    }

    iterator begin () {
        return _C_make_iter (_C_beg);
    }

    const_iterator begin () const {
        return _C_make_iter (_C_beg);
    }

    iterator end () {
        return _C_make_iter (_C_end);
    }

    const_iterator end () const {
        return _C_make_iter (_C_end);
    }

    reverse_iterator rbegin () {
        return reverse_iterator (end ());
    }

    const_reverse_iterator rbegin () const { 
        return const_reverse_iterator (end ());
    }
    
    reverse_iterator rend () { 
        return reverse_iterator (begin ());
    }

    const_reverse_iterator rend () const { 
        return const_reverse_iterator (begin ());
    }

    bool empty () const {
        return    _C_beg._C_node == _C_end._C_node
               && _C_beg._C_cur == _C_end._C_cur;
    }

    size_type size () const {
        return size_type (end () - begin ());
    }

    size_type max_size () const {
        return _RWSTD_VALUE_ALLOC (_C_value_alloc_type, *this, max_size ());
    }

    void resize (size_type, value_type = value_type ());

    reference operator[] (size_type __inx) {
#ifdef _RWSTD_BOUNDS_CHECKING
        return at (__inx);
#else
        _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));
        return *(begin () + __inx);
#endif
    }

    const_reference operator[] (size_type __inx) const {
#ifdef _RWSTD_BOUNDS_CHECKING
        return at (__inx);
#else
        _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));
        return *(begin () + __inx);
#endif
    }

    const_reference at (size_type __inx) const { 
        return _RWSTD_CONST_CAST (deque*, this)->at (__inx);
    }

    reference at (size_type __inx) {
        _RWSTD_REQUIRES (__inx < size (),
                         (_RWSTD_ERROR_OUT_OF_RANGE,
                          _RWSTD_FUNC ("deque::at(size_type)"),
                          __inx, size ()));
        return *(begin () + __inx);
    }

    reference front () {
        _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));
        return *begin ();
    }

    const_reference front () const {
        _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));
        return *begin ();
    }

    reference back () {
        _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));
        return *(end () - 1);
    }

    const_reference back () const {
        _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));
        return *(end () - 1);
    }

    void push_front (const_reference);

    void push_back (const_reference);

    iterator insert (iterator, const_reference);

    void insert (iterator __it, size_type __n, const_reference __x) {
        _C_insert_n (__it, __n, __x);
    }

    template <class _InputIter>
    void insert (iterator __it, _InputIter __first, _InputIter __last) {
        _C_insert (__it, __first, __last, _RWSTD_DISPATCH (_InputIter));
    }

    void pop_front ();

    void pop_back ();

    iterator erase (iterator);

    iterator erase (iterator, iterator);

    void swap (deque&);

    void clear () {
        erase (begin (), end ());

        _RWSTD_ASSERT (_C_is_valid (1 /* valid and empty */));
    }

#if defined (_RWSTD_NO_PART_SPEC_OVERLOAD)
    friend void swap (deque& __lhs, deque& __rhs) {
        __lhs.swap (__rhs);
    }
#endif


private:

    //////////////////////////////////////////////////////////////////
    // layout of a non-empty deque:
    //        
    //        +------------------- nodes [-1] (not used, 0
    //        | +----------------- nodes [0] (first usable)
    //        | |   +------------- beg.node
    //        | |   |     +------- end.node
    //        | |   |     |   +--- nodes [node_size - 1] (last usable)
    //        | |   |     |   | +- allocated but not used (0)
    //        | |   |     |   | |
    //        v v   v     v   v v
    //       +-+-+-+-+   +-+-+-+-+
    //       |0|X|X| |...| |X|X|0| dynamically sizable
    //       +-+-+-+-+   +-+-+-+-+
    //          ^   | ||| |
    //          |   v vvv v
    // nodes ---+  +-+   +-+ fixed-size arrays, all of the same size
    //             |X|...| |<-- end.node [0][0]
    //             +-+   +-+
    // beg.cur --->| |   | |<-- end.node [0][1]
    // (begin())   +-+   +-+
    //             | |   | |<-- end.node [0][2]
    //             ~ ~   ~ ~
    //             | |   | |
    //             +-+   +-+<-- end.cur (end())
    //             | |...|X|<-- (bufsize - 1)
    //             +-+   +-+

    // `beg.node' points to the first fixed-size array in `nodes'
    // `beg.cur' points at the first element in the array pointed
    // to by `beg.node' (it is null iff the container is empty)
    _C_deque_iter _C_beg;

    // `end.node' points to the last fixed-size array in `nodes'
    // `end.cur' points just past the last element in the array
    // pointed to by `end.node' (null iff the container is empty)
    _C_deque_iter _C_end;

    // `nodes' points to a dynamically sizable vector of `node_size'
    // nodes where each node is a pointer to a fixed-size array of
    // elements of value_type (null iff the container is empty)
    _C_node_pointer _C_nodes;

    // the capacity of the dynamically sizable vector of nodes
    // `node_size' is 0 for an empty deque; each (re)allocation
    // grows `node_size' to __rw_new_capacity(N, this) where N
    // is 0 is empty() and `end.node - beg.node + 1' otherwise
    size_type _C_node_size;

    void _C_init () {
        // clear both `beg.cur' and `end.cur' and set both `beg.node'
        // and `end.node' to point to `end.cur' (instead of 0) to avoid
        // having to check before dereferencing the pointers
        _C_beg       =
        _C_end       = _C_deque_iter (pointer (), &_C_end._C_cur);
        _C_nodes     = _C_node_pointer ();
        _C_node_size = 0;
    }

    void _C_push (bool, const_reference);

    void _C_free_at_begin ();

    void _C_free_at_end ();

private:

    // implements assign with repetition
    void _C_assign_n (size_type, const_reference);

    // implements a single-element insert
    void _C_insert_1 (const iterator&, const_reference);

    // implements insert with repetition
    void _C_insert_n (const iterator&, size_type, const_reference);

#ifndef _RWSTD_NO_MEMBER_TEMPLATES

    // implements range insert for BidirectionalIterators
    template <class _BidirIter>
    void _C_insert_range (iterator, _BidirIter, _BidirIter,
                          bidirectional_iterator_tag);

    // implements range insert for InputIterators
    template <class _InputIter>
    void _C_insert_range (iterator, _InputIter, _InputIter,
                          input_iterator_tag);

#else   // if defined (_RWSTD_NO_MEMBER_TEMPLATES)

public:

#endif   // _RWSTD_NO_MEMBER_TEMPLATES

    // implements range assign
    template <class _InputIter>
    void _C_assign (_InputIter __first, _InputIter __last, void*) {
        _RWSTD_ASSERT_RANGE (__first, __last);

        _RWSTD_ASSIGN_RANGE (__first, __last, input_iterator_tag ());
    }

    // implements assign with repetition if value_type == size_type
    template <class _IntType>
    void _C_assign (_IntType __n, _IntType __x, int) {
        // see 23.1.1, p9 and DR 438
        _C_assign_n (__n, __x);
    }

    // implements range insert for InputIterators
    template <class _InputIter>
    void _C_assign_range (_InputIter, _InputIter, input_iterator_tag);

    // implements range insert
    template <class _InputIter>
    void _C_insert (const iterator &__it,
                   _InputIter __first, _InputIter __last, void*) {
        _RWSTD_ASSERT_RANGE (begin (), __it);
        _RWSTD_ASSERT_RANGE (__first, __last);

        // dispatch to an insert suitable for the category of InputIter
        _RWSTD_INSERT_RANGE (__it, __first, __last,
                             _RWSTD_ITERATOR_CATEGORY (_InputIter, __first));
    }

    // implements insert with repetition if value_type == size_type
    template <class _IntType>
    void _C_insert (const iterator &__it,
                    _IntType __n, _IntType __x, int) {
        // see 23.1.1, p9 and DR 438
        _C_insert_n (__it, __n, __x);
    }


    bool _C_is_valid (int = -1) const;
};


template <class _TypeT, class _Allocator>
inline void
deque<_TypeT, _Allocator>::push_front (const_reference __x)
{
    _RWSTD_ASSERT (_C_is_valid ());

    if (_C_beg._C_cur == *_C_beg._C_node) {
        _C_push (false /* allocate at the beginning of vector */, __x);
    }
    else {
        _RWSTD_ASSERT (pointer () != _C_beg._C_cur);

        _RWSTD_VALUE_ALLOC (_C_value_alloc_type, *this,
                            construct (_C_beg._C_cur - 1, __x));
    }

    _RWSTD_ASSERT (pointer () != _C_beg._C_cur);

    --_C_beg._C_cur;

    _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));
}


template <class _TypeT, class _Allocator>
inline void
deque<_TypeT, _Allocator>::push_back (const_reference __x)
{
    _RWSTD_ASSERT (_C_is_valid ());

    if (   _C_end._C_cur == *_C_end._C_node + _C_bufsize ()
        || pointer () == _C_end._C_cur) {
        _C_push (true /* allocate at the end of vector */, __x);
    }
    else {
        _RWSTD_ASSERT (pointer () != _C_end._C_cur);

        _RWSTD_VALUE_ALLOC (_C_value_alloc_type, *this,
                            construct (_C_end._C_cur, __x));
    }

    _RWSTD_ASSERT (pointer () != _C_end._C_cur);

    ++_C_end._C_cur;

    _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));
}


template <class _TypeT, class _Allocator>
inline void
deque<_TypeT, _Allocator>::pop_front ()
{
    _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));

    const pointer __first = _C_beg._C_cur;

    _RWSTD_VALUE_ALLOC (_C_value_alloc_type, *this, destroy (__first));

    ++_C_beg._C_cur;

    if (empty () || _C_beg._C_cur == *_C_beg._C_node + _C_bufsize ()) 
        _C_free_at_begin ();

    _RWSTD_ASSERT (_C_is_valid ());
}


template <class _TypeT, class _Allocator>
inline void
deque<_TypeT, _Allocator>::pop_back ()
{
    _RWSTD_ASSERT (_C_is_valid (0 /* valid and non-empty */));

    const pointer __last = _C_end._C_cur - 1;

    _RWSTD_VALUE_ALLOC (_C_value_alloc_type, *this, destroy (__last));

    --_C_end._C_cur;

    if (empty () || _C_end._C_cur == *_C_end._C_node) 
        _C_free_at_end ();

    _RWSTD_ASSERT (_C_is_valid ());
}


template <class _TypeT, class _Allocator>
inline void
deque<_TypeT, _Allocator>::
resize (size_type __new_size, value_type __x /* = value_type () */)
{
    _RWSTD_ASSERT (_C_is_valid ());

    const size_type __size = size ();

    if (__size < __new_size)
        insert (end (), __new_size - __size, __x);
    else if (__new_size < __size)
        erase (begin () + __new_size, end ());
}


template <class _TypeT, class _Allocator>
inline bool
operator== (const deque<_TypeT, _Allocator> &__lhs,
            const deque<_TypeT, _Allocator> &__rhs)
{
//     _RWSTD_ASSERT (__lhs._C_is_valid ());
//     _RWSTD_ASSERT (__rhs._C_is_valid ());

    return    __lhs.size () == __rhs.size ()
           && _STD::equal (__lhs.begin (), __lhs.end (), __rhs.begin ());
}


template <class _TypeT, class _Allocator>
inline bool
operator< (const deque<_TypeT, _Allocator> &__lhs,
           const deque<_TypeT, _Allocator> &__rhs)
{
//     _RWSTD_ASSERT (__lhs._C_is_valid ());
//     _RWSTD_ASSERT (__rhs._C_is_valid ());

    return _STD::lexicographical_compare (__lhs.begin (), __lhs.end (),
                                          __rhs.begin (), __rhs.end ());
}


template <class _TypeT, class _Allocator>
inline bool
operator!= (const deque<_TypeT, _Allocator> &__lhs,
            const deque<_TypeT, _Allocator> &__rhs)
{
    return !(__lhs == __rhs);
}


template <class _TypeT, class _Allocator>
inline bool
operator<= (const deque<_TypeT, _Allocator> &__lhs,
            const deque<_TypeT, _Allocator> &__rhs)
{
    return !(__rhs < __lhs);
}


template <class _TypeT, class _Allocator>
inline bool
operator> (const deque<_TypeT, _Allocator> &__lhs,
           const deque<_TypeT, _Allocator> &__rhs)
{
    return __rhs < __lhs;
}


template <class _TypeT, class _Allocator>
inline bool
operator>= (const deque<_TypeT, _Allocator> &__lhs,
            const deque<_TypeT, _Allocator> &__rhs)
{
    return !(__lhs < __rhs);
}


#ifndef _RWSTD_NO_PART_SPEC_OVERLOAD

template <class _TypeT, class _Allocator>
inline void
swap (deque<_TypeT, _Allocator> &__lhs, deque<_TypeT, _Allocator> &__rhs)
{
    __lhs.swap (__rhs);
}

#endif   // _RWSTD_NO_PART_SPEC_OVERLOAD

}   // namespace end


#ifdef _RWSTD_NO_IMPLICIT_INCLUSION
#  include <deque.cc>
#endif


#ifndef _RWSTD_NO_STL_SPECIALIZATION
#  include "deque_spec.h"
#endif   // _RWSTD_NO_STL_SPECIALIZATION


#endif   // _RWSTD_DEQUE_INCLUDED