# stl_deque.h

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    00001 // Deque implementation -*- C++ -*-
    00002
    00003 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
    00004 // Free Software Foundation, Inc.
    00005 //
    00006 // This file is part of the GNU ISO C++ Library.  This library is free
    00007 // software; you can redistribute it and/or modify it under the
    00008 // terms of the GNU General Public License as published by the
    00009 // Free Software Foundation; either version 2, or (at your option)
    00010 // any later version.
    00011
    00012 // This library is distributed in the hope that it will be useful,
    00013 // but WITHOUT ANY WARRANTY; without even the implied warranty of
    00014 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    00015 // GNU General Public License for more details.
    00016
    00017 // You should have received a copy of the GNU General Public License along
    00018 // with this library; see the file COPYING.  If not, write to the Free
    00019 // Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
    00020 // USA.
    00021
    00022 // As a special exception, you may use this file as part of a free software
    00023 // library without restriction.  Specifically, if other files instantiate
    00024 // templates or use macros or inline functions from this file, or you compile
    00025 // this file and link it with other files to produce an executable, this
    00026 // file does not by itself cause the resulting executable to be covered by
    00027 // the GNU General Public License.  This exception does not however
    00028 // invalidate any other reasons why the executable file might be covered by
    00029 // the GNU General Public License.
    00030
    00031 /*
    00032  *
    00033  * Copyright (c) 1994
    00034  * Hewlett-Packard Company
    00035  *
    00036  * Permission to use, copy, modify, distribute and sell this software
    00037  * and its documentation for any purpose is hereby granted without fee,
    00038  * provided that the above copyright notice appear in all copies and
    00039  * that both that copyright notice and this permission notice appear
    00040  * in supporting documentation.  Hewlett-Packard Company makes no
    00041  * representations about the suitability of this software for any
    00042  * purpose.  It is provided "as is" without express or implied warranty.
    00043  *
    00044  *
    00045  * Copyright (c) 1997
    00046  * Silicon Graphics Computer Systems, Inc.
    00047  *
    00048  * Permission to use, copy, modify, distribute and sell this software
    00049  * and its documentation for any purpose is hereby granted without fee,
    00050  * provided that the above copyright notice appear in all copies and
    00051  * that both that copyright notice and this permission notice appear
    00052  * in supporting documentation.  Silicon Graphics makes no
    00053  * representations about the suitability of this software for any
    00054  * purpose.  It is provided "as is" without express or implied warranty.
    00055  */
    00056
    00057 /** @file stl_deque.h
    00058  *  This is an internal header file, included by other library headers.
    00059  *  You should not attempt to use it directly.
    00060  */
    00061
    00062 #ifndef _STL_DEQUE_H
    00063 #define _STL_DEQUE_H 1
    00064
    00065 #include <bits/concept_check.h>
    00066 #include <bits/stl_iterator_base_types.h>
    00067 #include <bits/stl_iterator_base_funcs.h>
    00068
    00069 _GLIBCXX_BEGIN_NESTED_NAMESPACE(std, _GLIBCXX_STD_D)
    00070
    00071   /**
    00072    *  @brief This function controls the size of memory nodes.
    00073    *  @param  size  The size of an element.
    00074    *  @return   The number (not byte size) of elements per node.
    00075    *
    00076    *  This function started off as a compiler kludge from SGI, but seems to
    00077    *  be a useful wrapper around a repeated constant expression.  The '512' is
    00078    *  tunable (and no other code needs to change), but no investigation has
    00079    *  been done since inheriting the SGI code.
    00080   */
    00081   inline size_t
    00082   __deque_buf_size(size_t __size)
    00083   { return __size < 512 ? size_t(512 / __size) : size_t(1); }
    00084
    00085
    00086   /**
    00087    *  @brief A deque::iterator.
    00088    *
    00089    *  Quite a bit of intelligence here.  Much of the functionality of
    00090    *  deque is actually passed off to this class.  A deque holds two
    00091    *  of these internally, marking its valid range.  Access to
    00092    *  elements is done as offsets of either of those two, relying on
    00093    *  operator overloading in this class.
    00094    *
    00095    *  All the functions are op overloads except for _M_set_node.
    00096   */
    00097   template<typename _Tp, typename _Ref, typename _Ptr>
    00098     struct _Deque_iterator
    00099     {
    00100       typedef _Deque_iterator<_Tp, _Tp&, _Tp*>             iterator;
    00101       typedef _Deque_iterator<_Tp, const _Tp&, const _Tp*> const_iterator;
    00102
    00103       static size_t _S_buffer_size()
    00104       { return __deque_buf_size(sizeof(_Tp)); }
    00105
    00106       typedef std::random_access_iterator_tag iterator_category;
    00107       typedef _Tp                             value_type;
    00108       typedef _Ptr                            pointer;
    00109       typedef _Ref                            reference;
    00110       typedef size_t                          size_type;
    00111       typedef ptrdiff_t                       difference_type;
    00112       typedef _Tp**                           _Map_pointer;
    00113       typedef _Deque_iterator                 _Self;
    00114
    00115       _Tp* _M_cur;
    00116       _Tp* _M_first;
    00117       _Tp* _M_last;
    00118       _Map_pointer _M_node;
    00119
    00120       _Deque_iterator(_Tp* __x, _Map_pointer __y)
    00121       : _M_cur(__x), _M_first(*__y),
    00122         _M_last(*__y + _S_buffer_size()), _M_node(__y) { }
    00123
    00124       _Deque_iterator()
    00125       : _M_cur(0), _M_first(0), _M_last(0), _M_node(0) { }
    00126
    00127       _Deque_iterator(const iterator& __x)
    00128       : _M_cur(__x._M_cur), _M_first(__x._M_first),
    00129         _M_last(__x._M_last), _M_node(__x._M_node) { }
    00130
    00131       reference
    00132       operator*() const
    00133       { return *_M_cur; }
    00134
    00135       pointer
    00136       operator->() const
    00137       { return _M_cur; }
    00138
    00139       _Self&
    00140       operator++()
    00141       {
    00142     ++_M_cur;
    00143     if (_M_cur == _M_last)
    00144       {
    00145         _M_set_node(_M_node + 1);
    00146         _M_cur = _M_first;
    00147       }
    00148     return *this;
    00149       }
    00150
    00151       _Self
    00152       operator++(int)
    00153       {
    00154     _Self __tmp = *this;
    00155     ++*this;
    00156     return __tmp;
    00157       }
    00158
    00159       _Self&
    00160       operator--()
    00161       {
    00162     if (_M_cur == _M_first)
    00163       {
    00164         _M_set_node(_M_node - 1);
    00165         _M_cur = _M_last;
    00166       }
    00167     --_M_cur;
    00168     return *this;
    00169       }
    00170
    00171       _Self
    00172       operator--(int)
    00173       {
    00174     _Self __tmp = *this;
    00175     --*this;
    00176     return __tmp;
    00177       }
    00178
    00179       _Self&
    00180       operator+=(difference_type __n)
    00181       {
    00182     const difference_type __offset = __n + (_M_cur - _M_first);
    00183     if (__offset >= 0 && __offset < difference_type(_S_buffer_size()))
    00184       _M_cur += __n;
    00185     else
    00186       {
    00187         const difference_type __node_offset =
    00188           __offset > 0 ? __offset / difference_type(_S_buffer_size())
    00189                        : -difference_type((-__offset - 1)
    00190                           / _S_buffer_size()) - 1;
    00191         _M_set_node(_M_node + __node_offset);
    00192         _M_cur = _M_first + (__offset - __node_offset
    00193                  * difference_type(_S_buffer_size()));
    00194       }
    00195     return *this;
    00196       }
    00197
    00198       _Self
    00199       operator+(difference_type __n) const
    00200       {
    00201     _Self __tmp = *this;
    00202     return __tmp += __n;
    00203       }
    00204
    00205       _Self&
    00206       operator-=(difference_type __n)
    00207       { return *this += -__n; }
    00208
    00209       _Self
    00210       operator-(difference_type __n) const
    00211       {
    00212     _Self __tmp = *this;
    00213     return __tmp -= __n;
    00214       }
    00215
    00216       reference
    00217       operator[](difference_type __n) const
    00218       { return *(*this + __n); }
    00219
    00220       /**
    00221        *  Prepares to traverse new_node.  Sets everything except
    00222        *  _M_cur, which should therefore be set by the caller
    00223        *  immediately afterwards, based on _M_first and _M_last.
    00224        */
    00225       void
    00226       _M_set_node(_Map_pointer __new_node)
    00227       {
    00228     _M_node = __new_node;
    00229     _M_first = *__new_node;
    00230     _M_last = _M_first + difference_type(_S_buffer_size());
    00231       }
    00232     };
    00233
    00234   // Note: we also provide overloads whose operands are of the same type in
    00235   // order to avoid ambiguous overload resolution when std::rel_ops operators
    00236   // are in scope (for additional details, see libstdc++/3628)
    00237   template<typename _Tp, typename _Ref, typename _Ptr>
    00238     inline bool
    00239     operator==(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
    00240            const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
    00241     { return __x._M_cur == __y._M_cur; }
    00242
    00243   template<typename _Tp, typename _RefL, typename _PtrL,
    00244        typename _RefR, typename _PtrR>
    00245     inline bool
    00246     operator==(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
    00247            const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
    00248     { return __x._M_cur == __y._M_cur; }
    00249
    00250   template<typename _Tp, typename _Ref, typename _Ptr>
    00251     inline bool
    00252     operator!=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
    00253            const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
    00254     { return !(__x == __y); }
    00255
    00256   template<typename _Tp, typename _RefL, typename _PtrL,
    00257        typename _RefR, typename _PtrR>
    00258     inline bool
    00259     operator!=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
    00260            const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
    00261     { return !(__x == __y); }
    00262
    00263   template<typename _Tp, typename _Ref, typename _Ptr>
    00264     inline bool
    00265     operator<(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
    00266           const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
    00267     { return (__x._M_node == __y._M_node) ? (__x._M_cur < __y._M_cur)
    00268                                           : (__x._M_node < __y._M_node); }
    00269
    00270   template<typename _Tp, typename _RefL, typename _PtrL,
    00271        typename _RefR, typename _PtrR>
    00272     inline bool
    00273     operator<(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
    00274           const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
    00275     { return (__x._M_node == __y._M_node) ? (__x._M_cur < __y._M_cur)
    00276                                       : (__x._M_node < __y._M_node); }
    00277
    00278   template<typename _Tp, typename _Ref, typename _Ptr>
    00279     inline bool
    00280     operator>(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
    00281           const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
    00282     { return __y < __x; }
    00283
    00284   template<typename _Tp, typename _RefL, typename _PtrL,
    00285        typename _RefR, typename _PtrR>
    00286     inline bool
    00287     operator>(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
    00288           const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
    00289     { return __y < __x; }
    00290
    00291   template<typename _Tp, typename _Ref, typename _Ptr>
    00292     inline bool
    00293     operator<=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
    00294            const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
    00295     { return !(__y < __x); }
    00296
    00297   template<typename _Tp, typename _RefL, typename _PtrL,
    00298        typename _RefR, typename _PtrR>
    00299     inline bool
    00300     operator<=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
    00301            const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
    00302     { return !(__y < __x); }
    00303
    00304   template<typename _Tp, typename _Ref, typename _Ptr>
    00305     inline bool
    00306     operator>=(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
    00307            const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
    00308     { return !(__x < __y); }
    00309
    00310   template<typename _Tp, typename _RefL, typename _PtrL,
    00311        typename _RefR, typename _PtrR>
    00312     inline bool
    00313     operator>=(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
    00314            const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
    00315     { return !(__x < __y); }
    00316
    00317   // _GLIBCXX_RESOLVE_LIB_DEFECTS
    00318   // According to the resolution of DR179 not only the various comparison
    00319   // operators but also operator- must accept mixed iterator/const_iterator
    00320   // parameters.
    00321   template<typename _Tp, typename _Ref, typename _Ptr>
    00322     inline typename _Deque_iterator<_Tp, _Ref, _Ptr>::difference_type
    00323     operator-(const _Deque_iterator<_Tp, _Ref, _Ptr>& __x,
    00324           const _Deque_iterator<_Tp, _Ref, _Ptr>& __y)
    00325     {
    00326       return typename _Deque_iterator<_Tp, _Ref, _Ptr>::difference_type
    00327     (_Deque_iterator<_Tp, _Ref, _Ptr>::_S_buffer_size())
    00328     * (__x._M_node - __y._M_node - 1) + (__x._M_cur - __x._M_first)
    00329     + (__y._M_last - __y._M_cur);
    00330     }
    00331
    00332   template<typename _Tp, typename _RefL, typename _PtrL,
    00333        typename _RefR, typename _PtrR>
    00334     inline typename _Deque_iterator<_Tp, _RefL, _PtrL>::difference_type
    00335     operator-(const _Deque_iterator<_Tp, _RefL, _PtrL>& __x,
    00336           const _Deque_iterator<_Tp, _RefR, _PtrR>& __y)
    00337     {
    00338       return typename _Deque_iterator<_Tp, _RefL, _PtrL>::difference_type
    00339     (_Deque_iterator<_Tp, _RefL, _PtrL>::_S_buffer_size())
    00340     * (__x._M_node - __y._M_node - 1) + (__x._M_cur - __x._M_first)
    00341     + (__y._M_last - __y._M_cur);
    00342     }
    00343
    00344   template<typename _Tp, typename _Ref, typename _Ptr>
    00345     inline _Deque_iterator<_Tp, _Ref, _Ptr>
    00346     operator+(ptrdiff_t __n, const _Deque_iterator<_Tp, _Ref, _Ptr>& __x)
    00347     { return __x + __n; }
    00348
    00349   template<typename _Tp>
    00350     void
    00351     fill(const _Deque_iterator<_Tp, _Tp&, _Tp*>& __first,
    00352      const _Deque_iterator<_Tp, _Tp&, _Tp*>& __last, const _Tp& __value);
    00353
    00354   /**
    00355    *  Deque base class.  This class provides the unified face for %deque's
    00356    *  allocation.  This class's constructor and destructor allocate and
    00357    *  deallocate (but do not initialize) storage.  This makes %exception
    00358    *  safety easier.
    00359    *
    00360    *  Nothing in this class ever constructs or destroys an actual Tp element.
    00361    *  (Deque handles that itself.)  Only/All memory management is performed
    00362    *  here.
    00363   */
    00364   template<typename _Tp, typename _Alloc>
    00365     class _Deque_base
    00366     {
    00367     public:
    00368       typedef _Alloc                  allocator_type;
    00369
    00370       allocator_type
    00371       get_allocator() const
    00372       { return allocator_type(_M_get_Tp_allocator()); }
    00373
    00374       typedef _Deque_iterator<_Tp, _Tp&, _Tp*>             iterator;
    00375       typedef _Deque_iterator<_Tp, const _Tp&, const _Tp*> const_iterator;
    00376
    00377       _Deque_base()
    00378       : _M_impl()
    00379       { _M_initialize_map(0); }
    00380
    00381       _Deque_base(const allocator_type& __a, size_t __num_elements)
    00382       : _M_impl(__a)
    00383       { _M_initialize_map(__num_elements); }
    00384
    00385       _Deque_base(const allocator_type& __a)
    00386       : _M_impl(__a)
    00387       { }
    00388
    00389 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00390       _Deque_base(_Deque_base&& __x)
    00391       : _M_impl(__x._M_get_Tp_allocator())
    00392       {
    00393     _M_initialize_map(0);
    00394     if (__x._M_impl._M_map)
    00395       {
    00396         std::swap(this->_M_impl._M_start, __x._M_impl._M_start);
    00397         std::swap(this->_M_impl._M_finish, __x._M_impl._M_finish);
    00398         std::swap(this->_M_impl._M_map, __x._M_impl._M_map);
    00399         std::swap(this->_M_impl._M_map_size, __x._M_impl._M_map_size);
    00400       }
    00401       }
    00402 #endif
    00403
    00404       ~_Deque_base();
    00405
    00406     protected:
    00407       //This struct encapsulates the implementation of the std::deque
    00408       //standard container and at the same time makes use of the EBO
    00409       //for empty allocators.
    00410       typedef typename _Alloc::template rebind<_Tp*>::other _Map_alloc_type;
    00411
    00412       typedef typename _Alloc::template rebind<_Tp>::other  _Tp_alloc_type;
    00413
    00414       struct _Deque_impl
    00415       : public _Tp_alloc_type
    00416       {
    00417     _Tp** _M_map;
    00418     size_t _M_map_size;
    00419     iterator _M_start;
    00420     iterator _M_finish;
    00421
    00422     _Deque_impl()
    00423     : _Tp_alloc_type(), _M_map(0), _M_map_size(0),
    00424       _M_start(), _M_finish()
    00425     { }
    00426
    00427     _Deque_impl(const _Tp_alloc_type& __a)
    00428     : _Tp_alloc_type(__a), _M_map(0), _M_map_size(0),
    00429       _M_start(), _M_finish()
    00430     { }
    00431       };
    00432
    00433       _Tp_alloc_type&
    00434       _M_get_Tp_allocator()
    00435       { return *static_cast<_Tp_alloc_type*>(&this->_M_impl); }
    00436
    00437       const _Tp_alloc_type&
    00438       _M_get_Tp_allocator() const
    00439       { return *static_cast<const _Tp_alloc_type*>(&this->_M_impl); }
    00440
    00441       _Map_alloc_type
    00442       _M_get_map_allocator() const
    00443       { return _Map_alloc_type(_M_get_Tp_allocator()); }
    00444
    00445       _Tp*
    00446       _M_allocate_node()
    00447       {
    00448     return _M_impl._Tp_alloc_type::allocate(__deque_buf_size(sizeof(_Tp)));
    00449       }
    00450
    00451       void
    00452       _M_deallocate_node(_Tp* __p)
    00453       {
    00454     _M_impl._Tp_alloc_type::deallocate(__p, __deque_buf_size(sizeof(_Tp)));
    00455       }
    00456
    00457       _Tp**
    00458       _M_allocate_map(size_t __n)
    00459       { return _M_get_map_allocator().allocate(__n); }
    00460
    00461       void
    00462       _M_deallocate_map(_Tp** __p, size_t __n)
    00463       { _M_get_map_allocator().deallocate(__p, __n); }
    00464
    00465     protected:
    00466       void _M_initialize_map(size_t);
    00467       void _M_create_nodes(_Tp** __nstart, _Tp** __nfinish);
    00468       void _M_destroy_nodes(_Tp** __nstart, _Tp** __nfinish);
    00469       enum { _S_initial_map_size = 8 };
    00470
    00471       _Deque_impl _M_impl;
    00472     };
    00473
    00474   template<typename _Tp, typename _Alloc>
    00475     _Deque_base<_Tp, _Alloc>::
    00476     ~_Deque_base()
    00477     {
    00478       if (this->_M_impl._M_map)
    00479     {
    00480       _M_destroy_nodes(this->_M_impl._M_start._M_node,
    00481                this->_M_impl._M_finish._M_node + 1);
    00482       _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
    00483     }
    00484     }
    00485
    00486   /**
    00487    *  @brief Layout storage.
    00488    *  @param  num_elements  The count of T's for which to allocate space
    00489    *                        at first.
    00490    *  @return   Nothing.
    00491    *
    00492    *  The initial underlying memory layout is a bit complicated...
    00493   */
    00494   template<typename _Tp, typename _Alloc>
    00495     void
    00496     _Deque_base<_Tp, _Alloc>::
    00497     _M_initialize_map(size_t __num_elements)
    00498     {
    00499       const size_t __num_nodes = (__num_elements/ __deque_buf_size(sizeof(_Tp))
    00500                   + 1);
    00501
    00502       this->_M_impl._M_map_size = std::max((size_t) _S_initial_map_size,
    00503                        size_t(__num_nodes + 2));
    00504       this->_M_impl._M_map = _M_allocate_map(this->_M_impl._M_map_size);
    00505
    00506       // For "small" maps (needing less than _M_map_size nodes), allocation
    00507       // starts in the middle elements and grows outwards.  So nstart may be
    00508       // the beginning of _M_map, but for small maps it may be as far in as
    00509       // _M_map+3.
    00510
    00511       _Tp** __nstart = (this->_M_impl._M_map
    00512             + (this->_M_impl._M_map_size - __num_nodes) / 2);
    00513       _Tp** __nfinish = __nstart + __num_nodes;
    00514
    00515       try
    00516     { _M_create_nodes(__nstart, __nfinish); }
    00517       catch(...)
    00518     {
    00519       _M_deallocate_map(this->_M_impl._M_map, this->_M_impl._M_map_size);
    00520       this->_M_impl._M_map = 0;
    00521       this->_M_impl._M_map_size = 0;
    00522       __throw_exception_again;
    00523     }
    00524
    00525       this->_M_impl._M_start._M_set_node(__nstart);
    00526       this->_M_impl._M_finish._M_set_node(__nfinish - 1);
    00527       this->_M_impl._M_start._M_cur = _M_impl._M_start._M_first;
    00528       this->_M_impl._M_finish._M_cur = (this->_M_impl._M_finish._M_first
    00529                     + __num_elements
    00530                     % __deque_buf_size(sizeof(_Tp)));
    00531     }
    00532
    00533   template<typename _Tp, typename _Alloc>
    00534     void
    00535     _Deque_base<_Tp, _Alloc>::
    00536     _M_create_nodes(_Tp** __nstart, _Tp** __nfinish)
    00537     {
    00538       _Tp** __cur;
    00539       try
    00540     {
    00541       for (__cur = __nstart; __cur < __nfinish; ++__cur)
    00542         *__cur = this->_M_allocate_node();
    00543     }
    00544       catch(...)
    00545     {
    00546       _M_destroy_nodes(__nstart, __cur);
    00547       __throw_exception_again;
    00548     }
    00549     }
    00550
    00551   template<typename _Tp, typename _Alloc>
    00552     void
    00553     _Deque_base<_Tp, _Alloc>::
    00554     _M_destroy_nodes(_Tp** __nstart, _Tp** __nfinish)
    00555     {
    00556       for (_Tp** __n = __nstart; __n < __nfinish; ++__n)
    00557     _M_deallocate_node(*__n);
    00558     }
    00559
    00560   /**
    00561    *  @brief  A standard container using fixed-size memory allocation and
    00562    *  constant-time manipulation of elements at either end.
    00563    *
    00564    *  @ingroup Containers
    00565    *  @ingroup Sequences
    00566    *
    00567    *  Meets the requirements of a <a href="tables.html#65">container</a>, a
    00568    *  <a href="tables.html#66">reversible container</a>, and a
    00569    *  <a href="tables.html#67">sequence</a>, including the
    00570    *  <a href="tables.html#68">optional sequence requirements</a>.
    00571    *
    00572    *  In previous HP/SGI versions of deque, there was an extra template
    00573    *  parameter so users could control the node size.  This extension turned
    00574    *  out to violate the C++ standard (it can be detected using template
    00575    *  template parameters), and it was removed.
    00576    *
    00577    *  Here's how a deque<Tp> manages memory.  Each deque has 4 members:
    00578    *
    00579    *  - Tp**        _M_map
    00580    *  - size_t      _M_map_size
    00581    *  - iterator    _M_start, _M_finish
    00582    *
    00583    *  map_size is at least 8.  %map is an array of map_size
    00584    *  pointers-to-"nodes".  (The name %map has nothing to do with the
    00585    *  std::map class, and "nodes" should not be confused with
    00586    *  std::list's usage of "node".)
    00587    *
    00588    *  A "node" has no specific type name as such, but it is referred
    00589    *  to as "node" in this file.  It is a simple array-of-Tp.  If Tp
    00590    *  is very large, there will be one Tp element per node (i.e., an
    00591    *  "array" of one).  For non-huge Tp's, node size is inversely
    00592    *  related to Tp size: the larger the Tp, the fewer Tp's will fit
    00593    *  in a node.  The goal here is to keep the total size of a node
    00594    *  relatively small and constant over different Tp's, to improve
    00595    *  allocator efficiency.
    00596    *
    00597    *  Not every pointer in the %map array will point to a node.  If
    00598    *  the initial number of elements in the deque is small, the
    00599    *  /middle/ %map pointers will be valid, and the ones at the edges
    00600    *  will be unused.  This same situation will arise as the %map
    00601    *  grows: available %map pointers, if any, will be on the ends.  As
    00602    *  new nodes are created, only a subset of the %map's pointers need
    00603    *  to be copied "outward".
    00604    *
    00605    *  Class invariants:
    00606    * - For any nonsingular iterator i:
    00607    *    - i.node points to a member of the %map array.  (Yes, you read that
    00608    *      correctly:  i.node does not actually point to a node.)  The member of
    00609    *      the %map array is what actually points to the node.
    00610    *    - i.first == *(i.node)    (This points to the node (first Tp element).)
    00611    *    - i.last  == i.first + node_size
    00612    *    - i.cur is a pointer in the range [i.first, i.last).  NOTE:
    00613    *      the implication of this is that i.cur is always a dereferenceable
    00614    *      pointer, even if i is a past-the-end iterator.
    00615    * - Start and Finish are always nonsingular iterators.  NOTE: this
    00616    * means that an empty deque must have one node, a deque with <N
    00617    * elements (where N is the node buffer size) must have one node, a
    00618    * deque with N through (2N-1) elements must have two nodes, etc.
    00619    * - For every node other than start.node and finish.node, every
    00620    * element in the node is an initialized object.  If start.node ==
    00621    * finish.node, then [start.cur, finish.cur) are initialized
    00622    * objects, and the elements outside that range are uninitialized
    00623    * storage.  Otherwise, [start.cur, start.last) and [finish.first,
    00624    * finish.cur) are initialized objects, and [start.first, start.cur)
    00625    * and [finish.cur, finish.last) are uninitialized storage.
    00626    * - [%map, %map + map_size) is a valid, non-empty range.
    00627    * - [start.node, finish.node] is a valid range contained within
    00628    *   [%map, %map + map_size).
    00629    * - A pointer in the range [%map, %map + map_size) points to an allocated
    00630    *   node if and only if the pointer is in the range
    00631    *   [start.node, finish.node].
    00632    *
    00633    *  Here's the magic:  nothing in deque is "aware" of the discontiguous
    00634    *  storage!
    00635    *
    00636    *  The memory setup and layout occurs in the parent, _Base, and the iterator
    00637    *  class is entirely responsible for "leaping" from one node to the next.
    00638    *  All the implementation routines for deque itself work only through the
    00639    *  start and finish iterators.  This keeps the routines simple and sane,
    00640    *  and we can use other standard algorithms as well.
    00641   */
    00642   template<typename _Tp, typename _Alloc = std::allocator<_Tp> >
    00643     class deque : protected _Deque_base<_Tp, _Alloc>
    00644     {
    00645       // concept requirements
    00646       typedef typename _Alloc::value_type        _Alloc_value_type;
    00647       __glibcxx_class_requires(_Tp, _SGIAssignableConcept)
    00648       __glibcxx_class_requires2(_Tp, _Alloc_value_type, _SameTypeConcept)
    00649
    00650       typedef _Deque_base<_Tp, _Alloc>           _Base;
    00651       typedef typename _Base::_Tp_alloc_type     _Tp_alloc_type;
    00652
    00653     public:
    00654       typedef _Tp                                        value_type;
    00655       typedef typename _Tp_alloc_type::pointer           pointer;
    00656       typedef typename _Tp_alloc_type::const_pointer     const_pointer;
    00657       typedef typename _Tp_alloc_type::reference         reference;
    00658       typedef typename _Tp_alloc_type::const_reference   const_reference;
    00659       typedef typename _Base::iterator                   iterator;
    00660       typedef typename _Base::const_iterator             const_iterator;
    00661       typedef std::reverse_iterator<const_iterator>      const_reverse_iterator;
    00662       typedef std::reverse_iterator<iterator>            reverse_iterator;
    00663       typedef size_t                             size_type;
    00664       typedef ptrdiff_t                          difference_type;
    00665       typedef _Alloc                             allocator_type;
    00666
    00667     protected:
    00668       typedef pointer*                           _Map_pointer;
    00669
    00670       static size_t _S_buffer_size()
    00671       { return __deque_buf_size(sizeof(_Tp)); }
    00672
    00673       // Functions controlling memory layout, and nothing else.
    00674       using _Base::_M_initialize_map;
    00675       using _Base::_M_create_nodes;
    00676       using _Base::_M_destroy_nodes;
    00677       using _Base::_M_allocate_node;
    00678       using _Base::_M_deallocate_node;
    00679       using _Base::_M_allocate_map;
    00680       using _Base::_M_deallocate_map;
    00681       using _Base::_M_get_Tp_allocator;
    00682
    00683       /**
    00684        *  A total of four data members accumulated down the hierarchy.
    00685        *  May be accessed via _M_impl.*
    00686        */
    00687       using _Base::_M_impl;
    00688
    00689     public:
    00690       // [23.2.1.1] construct/copy/destroy
    00691       // (assign() and get_allocator() are also listed in this section)
    00692       /**
    00693        *  @brief  Default constructor creates no elements.
    00694        */
    00695       deque()
    00696       : _Base() { }
    00697
    00698       /**
    00699        *  @brief  Creates a %deque with no elements.
    00700        *  @param  a  An allocator object.
    00701        */
    00702       explicit
    00703       deque(const allocator_type& __a)
    00704       : _Base(__a, 0) { }
    00705
    00706       /**
    00707        *  @brief  Creates a %deque with copies of an exemplar element.
    00708        *  @param  n  The number of elements to initially create.
    00709        *  @param  value  An element to copy.
    00710        *  @param  a  An allocator.
    00711        *
    00712        *  This constructor fills the %deque with @a n copies of @a value.
    00713        */
    00714       explicit
    00715       deque(size_type __n, const value_type& __value = value_type(),
    00716         const allocator_type& __a = allocator_type())
    00717       : _Base(__a, __n)
    00718       { _M_fill_initialize(__value); }
    00719
    00720       /**
    00721        *  @brief  %Deque copy constructor.
    00722        *  @param  x  A %deque of identical element and allocator types.
    00723        *
    00724        *  The newly-created %deque uses a copy of the allocation object used
    00725        *  by @a x.
    00726        */
    00727       deque(const deque& __x)
    00728       : _Base(__x._M_get_Tp_allocator(), __x.size())
    00729       { std::__uninitialized_copy_a(__x.begin(), __x.end(),
    00730                     this->_M_impl._M_start,
    00731                     _M_get_Tp_allocator()); }
    00732
    00733 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00734       /**
    00735        *  @brief  %Deque move constructor.
    00736        *  @param  x  A %deque of identical element and allocator types.
    00737        *
    00738        *  The newly-created %deque contains the exact contents of @a x.
    00739        *  The contents of @a x are a valid, but unspecified %deque.
    00740        */
    00741       deque(deque&&  __x)
    00742       : _Base(std::forward<_Base>(__x)) { }
    00743 #endif
    00744
    00745       /**
    00746        *  @brief  Builds a %deque from a range.
    00747        *  @param  first  An input iterator.
    00748        *  @param  last  An input iterator.
    00749        *  @param  a  An allocator object.
    00750        *
    00751        *  Create a %deque consisting of copies of the elements from [first,
    00752        *  last).
    00753        *
    00754        *  If the iterators are forward, bidirectional, or random-access, then
    00755        *  this will call the elements' copy constructor N times (where N is
    00756        *  distance(first,last)) and do no memory reallocation.  But if only
    00757        *  input iterators are used, then this will do at most 2N calls to the
    00758        *  copy constructor, and logN memory reallocations.
    00759        */
    00760       template<typename _InputIterator>
    00761         deque(_InputIterator __first, _InputIterator __last,
    00762           const allocator_type& __a = allocator_type())
    00763     : _Base(__a)
    00764         {
    00765       // Check whether it's an integral type.  If so, it's not an iterator.
    00766       typedef typename std::__is_integer<_InputIterator>::__type _Integral;
    00767       _M_initialize_dispatch(__first, __last, _Integral());
    00768     }
    00769
    00770       /**
    00771        *  The dtor only erases the elements, and note that if the elements
    00772        *  themselves are pointers, the pointed-to memory is not touched in any
    00773        *  way.  Managing the pointer is the user's responsibility.
    00774        */
    00775       ~deque()
    00776       { _M_destroy_data(begin(), end(), _M_get_Tp_allocator()); }
    00777
    00778       /**
    00779        *  @brief  %Deque assignment operator.
    00780        *  @param  x  A %deque of identical element and allocator types.
    00781        *
    00782        *  All the elements of @a x are copied, but unlike the copy constructor,
    00783        *  the allocator object is not copied.
    00784        */
    00785       deque&
    00786       operator=(const deque& __x);
    00787
    00788 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00789       /**
    00790        *  @brief  %Deque move assignment operator.
    00791        *  @param  x  A %deque of identical element and allocator types.
    00792        *
    00793        *  The contents of @a x are moved into this deque (without copying).
    00794        *  @a x is a valid, but unspecified %deque.
    00795        */
    00796       deque&
    00797       operator=(deque&& __x)
    00798       {
    00799     // NB: DR 675.
    00800     this->clear();
    00801     this->swap(__x);
    00802     return *this;
    00803       }
    00804 #endif
    00805
    00806       /**
    00807        *  @brief  Assigns a given value to a %deque.
    00808        *  @param  n  Number of elements to be assigned.
    00809        *  @param  val  Value to be assigned.
    00810        *
    00811        *  This function fills a %deque with @a n copies of the given
    00812        *  value.  Note that the assignment completely changes the
    00813        *  %deque and that the resulting %deque's size is the same as
    00814        *  the number of elements assigned.  Old data may be lost.
    00815        */
    00816       void
    00817       assign(size_type __n, const value_type& __val)
    00818       { _M_fill_assign(__n, __val); }
    00819
    00820       /**
    00821        *  @brief  Assigns a range to a %deque.
    00822        *  @param  first  An input iterator.
    00823        *  @param  last   An input iterator.
    00824        *
    00825        *  This function fills a %deque with copies of the elements in the
    00826        *  range [first,last).
    00827        *
    00828        *  Note that the assignment completely changes the %deque and that the
    00829        *  resulting %deque's size is the same as the number of elements
    00830        *  assigned.  Old data may be lost.
    00831        */
    00832       template<typename _InputIterator>
    00833         void
    00834         assign(_InputIterator __first, _InputIterator __last)
    00835         {
    00836       typedef typename std::__is_integer<_InputIterator>::__type _Integral;
    00837       _M_assign_dispatch(__first, __last, _Integral());
    00838     }
    00839
    00840       /// Get a copy of the memory allocation object.
    00841       allocator_type
    00842       get_allocator() const
    00843       { return _Base::get_allocator(); }
    00844
    00845       // iterators
    00846       /**
    00847        *  Returns a read/write iterator that points to the first element in the
    00848        *  %deque.  Iteration is done in ordinary element order.
    00849        */
    00850       iterator
    00851       begin()
    00852       { return this->_M_impl._M_start; }
    00853
    00854       /**
    00855        *  Returns a read-only (constant) iterator that points to the first
    00856        *  element in the %deque.  Iteration is done in ordinary element order.
    00857        */
    00858       const_iterator
    00859       begin() const
    00860       { return this->_M_impl._M_start; }
    00861
    00862       /**
    00863        *  Returns a read/write iterator that points one past the last
    00864        *  element in the %deque.  Iteration is done in ordinary
    00865        *  element order.
    00866        */
    00867       iterator
    00868       end()
    00869       { return this->_M_impl._M_finish; }
    00870
    00871       /**
    00872        *  Returns a read-only (constant) iterator that points one past
    00873        *  the last element in the %deque.  Iteration is done in
    00874        *  ordinary element order.
    00875        */
    00876       const_iterator
    00877       end() const
    00878       { return this->_M_impl._M_finish; }
    00879
    00880       /**
    00881        *  Returns a read/write reverse iterator that points to the
    00882        *  last element in the %deque.  Iteration is done in reverse
    00883        *  element order.
    00884        */
    00885       reverse_iterator
    00886       rbegin()
    00887       { return reverse_iterator(this->_M_impl._M_finish); }
    00888
    00889       /**
    00890        *  Returns a read-only (constant) reverse iterator that points
    00891        *  to the last element in the %deque.  Iteration is done in
    00892        *  reverse element order.
    00893        */
    00894       const_reverse_iterator
    00895       rbegin() const
    00896       { return const_reverse_iterator(this->_M_impl._M_finish); }
    00897
    00898       /**
    00899        *  Returns a read/write reverse iterator that points to one
    00900        *  before the first element in the %deque.  Iteration is done
    00901        *  in reverse element order.
    00902        */
    00903       reverse_iterator
    00904       rend()
    00905       { return reverse_iterator(this->_M_impl._M_start); }
    00906
    00907       /**
    00908        *  Returns a read-only (constant) reverse iterator that points
    00909        *  to one before the first element in the %deque.  Iteration is
    00910        *  done in reverse element order.
    00911        */
    00912       const_reverse_iterator
    00913       rend() const
    00914       { return const_reverse_iterator(this->_M_impl._M_start); }
    00915
    00916 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    00917       /**
    00918        *  Returns a read-only (constant) iterator that points to the first
    00919        *  element in the %deque.  Iteration is done in ordinary element order.
    00920        */
    00921       const_iterator
    00922       cbegin() const
    00923       { return this->_M_impl._M_start; }
    00924
    00925       /**
    00926        *  Returns a read-only (constant) iterator that points one past
    00927        *  the last element in the %deque.  Iteration is done in
    00928        *  ordinary element order.
    00929        */
    00930       const_iterator
    00931       cend() const
    00932       { return this->_M_impl._M_finish; }
    00933
    00934       /**
    00935        *  Returns a read-only (constant) reverse iterator that points
    00936        *  to the last element in the %deque.  Iteration is done in
    00937        *  reverse element order.
    00938        */
    00939       const_reverse_iterator
    00940       crbegin() const
    00941       { return const_reverse_iterator(this->_M_impl._M_finish); }
    00942
    00943       /**
    00944        *  Returns a read-only (constant) reverse iterator that points
    00945        *  to one before the first element in the %deque.  Iteration is
    00946        *  done in reverse element order.
    00947        */
    00948       const_reverse_iterator
    00949       crend() const
    00950       { return const_reverse_iterator(this->_M_impl._M_start); }
    00951 #endif
    00952
    00953       // [23.2.1.2] capacity
    00954       /**  Returns the number of elements in the %deque.  */
    00955       size_type
    00956       size() const
    00957       { return this->_M_impl._M_finish - this->_M_impl._M_start; }
    00958
    00959       /**  Returns the size() of the largest possible %deque.  */
    00960       size_type
    00961       max_size() const
    00962       { return _M_get_Tp_allocator().max_size(); }
    00963
    00964       /**
    00965        *  @brief  Resizes the %deque to the specified number of elements.
    00966        *  @param  new_size  Number of elements the %deque should contain.
    00967        *  @param  x  Data with which new elements should be populated.
    00968        *
    00969        *  This function will %resize the %deque to the specified
    00970        *  number of elements.  If the number is smaller than the
    00971        *  %deque's current size the %deque is truncated, otherwise the
    00972        *  %deque is extended and new elements are populated with given
    00973        *  data.
    00974        */
    00975       void
    00976       resize(size_type __new_size, value_type __x = value_type())
    00977       {
    00978     const size_type __len = size();
    00979     if (__new_size < __len)
    00980       _M_erase_at_end(this->_M_impl._M_start + difference_type(__new_size));
    00981     else
    00982       insert(this->_M_impl._M_finish, __new_size - __len, __x);
    00983       }
    00984
    00985       /**
    00986        *  Returns true if the %deque is empty.  (Thus begin() would
    00987        *  equal end().)
    00988        */
    00989       bool
    00990       empty() const
    00991       { return this->_M_impl._M_finish == this->_M_impl._M_start; }
    00992
    00993       // element access
    00994       /**
    00995        *  @brief Subscript access to the data contained in the %deque.
    00996        *  @param n The index of the element for which data should be
    00997        *  accessed.
    00998        *  @return  Read/write reference to data.
    00999        *
    01000        *  This operator allows for easy, array-style, data access.
    01001        *  Note that data access with this operator is unchecked and
    01002        *  out_of_range lookups are not defined. (For checked lookups
    01003        *  see at().)
    01004        */
    01005       reference
    01006       operator[](size_type __n)
    01007       { return this->_M_impl._M_start[difference_type(__n)]; }
    01008
    01009       /**
    01010        *  @brief Subscript access to the data contained in the %deque.
    01011        *  @param n The index of the element for which data should be
    01012        *  accessed.
    01013        *  @return  Read-only (constant) reference to data.
    01014        *
    01015        *  This operator allows for easy, array-style, data access.
    01016        *  Note that data access with this operator is unchecked and
    01017        *  out_of_range lookups are not defined. (For checked lookups
    01018        *  see at().)
    01019        */
    01020       const_reference
    01021       operator[](size_type __n) const
    01022       { return this->_M_impl._M_start[difference_type(__n)]; }
    01023
    01024     protected:
    01025       /// Safety check used only from at().
    01026       void
    01027       _M_range_check(size_type __n) const
    01028       {
    01029     if (__n >= this->size())
    01030       __throw_out_of_range(__N("deque::_M_range_check"));
    01031       }
    01032
    01033     public:
    01034       /**
    01035        *  @brief  Provides access to the data contained in the %deque.
    01036        *  @param n The index of the element for which data should be
    01037        *  accessed.
    01038        *  @return  Read/write reference to data.
    01039        *  @throw  std::out_of_range  If @a n is an invalid index.
    01040        *
    01041        *  This function provides for safer data access.  The parameter
    01042        *  is first checked that it is in the range of the deque.  The
    01043        *  function throws out_of_range if the check fails.
    01044        */
    01045       reference
    01046       at(size_type __n)
    01047       {
    01048     _M_range_check(__n);
    01049     return (*this)[__n];
    01050       }
    01051
    01052       /**
    01053        *  @brief  Provides access to the data contained in the %deque.
    01054        *  @param n The index of the element for which data should be
    01055        *  accessed.
    01056        *  @return  Read-only (constant) reference to data.
    01057        *  @throw  std::out_of_range  If @a n is an invalid index.
    01058        *
    01059        *  This function provides for safer data access.  The parameter is first
    01060        *  checked that it is in the range of the deque.  The function throws
    01061        *  out_of_range if the check fails.
    01062        */
    01063       const_reference
    01064       at(size_type __n) const
    01065       {
    01066     _M_range_check(__n);
    01067     return (*this)[__n];
    01068       }
    01069
    01070       /**
    01071        *  Returns a read/write reference to the data at the first
    01072        *  element of the %deque.
    01073        */
    01074       reference
    01075       front()
    01076       { return *begin(); }
    01077
    01078       /**
    01079        *  Returns a read-only (constant) reference to the data at the first
    01080        *  element of the %deque.
    01081        */
    01082       const_reference
    01083       front() const
    01084       { return *begin(); }
    01085
    01086       /**
    01087        *  Returns a read/write reference to the data at the last element of the
    01088        *  %deque.
    01089        */
    01090       reference
    01091       back()
    01092       {
    01093     iterator __tmp = end();
    01094     --__tmp;
    01095     return *__tmp;
    01096       }
    01097
    01098       /**
    01099        *  Returns a read-only (constant) reference to the data at the last
    01100        *  element of the %deque.
    01101        */
    01102       const_reference
    01103       back() const
    01104       {
    01105     const_iterator __tmp = end();
    01106     --__tmp;
    01107     return *__tmp;
    01108       }
    01109
    01110       // [23.2.1.2] modifiers
    01111       /**
    01112        *  @brief  Add data to the front of the %deque.
    01113        *  @param  x  Data to be added.
    01114        *
    01115        *  This is a typical stack operation.  The function creates an
    01116        *  element at the front of the %deque and assigns the given
    01117        *  data to it.  Due to the nature of a %deque this operation
    01118        *  can be done in constant time.
    01119        */
    01120 #ifndef __GXX_EXPERIMENTAL_CXX0X__
    01121       void
    01122       push_front(const value_type& __x)
    01123       {
    01124     if (this->_M_impl._M_start._M_cur != this->_M_impl._M_start._M_first)
    01125       {
    01126         this->_M_impl.construct(this->_M_impl._M_start._M_cur - 1, __x);
    01127         --this->_M_impl._M_start._M_cur;
    01128       }
    01129     else
    01130       _M_push_front_aux(__x);
    01131       }
    01132 #else
    01133       template<typename... _Args>
    01134         void
    01135         push_front(_Args&&... __args)
    01136     {
    01137       if (this->_M_impl._M_start._M_cur != this->_M_impl._M_start._M_first)
    01138         {
    01139           this->_M_impl.construct(this->_M_impl._M_start._M_cur - 1,
    01140                       std::forward<_Args>(__args)...);
    01141           --this->_M_impl._M_start._M_cur;
    01142         }
    01143       else
    01144         _M_push_front_aux(std::forward<_Args>(__args)...);
    01145     }
    01146 #endif
    01147
    01148       /**
    01149        *  @brief  Add data to the end of the %deque.
    01150        *  @param  x  Data to be added.
    01151        *
    01152        *  This is a typical stack operation.  The function creates an
    01153        *  element at the end of the %deque and assigns the given data
    01154        *  to it.  Due to the nature of a %deque this operation can be
    01155        *  done in constant time.
    01156        */
    01157 #ifndef __GXX_EXPERIMENTAL_CXX0X__
    01158       void
    01159       push_back(const value_type& __x)
    01160       {
    01161     if (this->_M_impl._M_finish._M_cur
    01162         != this->_M_impl._M_finish._M_last - 1)
    01163       {
    01164         this->_M_impl.construct(this->_M_impl._M_finish._M_cur, __x);
    01165         ++this->_M_impl._M_finish._M_cur;
    01166       }
    01167     else
    01168       _M_push_back_aux(__x);
    01169       }
    01170 #else
    01171       template<typename... _Args>
    01172         void
    01173         push_back(_Args&&... __args)
    01174     {
    01175       if (this->_M_impl._M_finish._M_cur
    01176           != this->_M_impl._M_finish._M_last - 1)
    01177         {
    01178           this->_M_impl.construct(this->_M_impl._M_finish._M_cur,
    01179                       std::forward<_Args>(__args)...);
    01180           ++this->_M_impl._M_finish._M_cur;
    01181         }
    01182       else
    01183         _M_push_back_aux(std::forward<_Args>(__args)...);
    01184     }
    01185 #endif
    01186
    01187       /**
    01188        *  @brief  Removes first element.
    01189        *
    01190        *  This is a typical stack operation.  It shrinks the %deque by one.
    01191        *
    01192        *  Note that no data is returned, and if the first element's data is
    01193        *  needed, it should be retrieved before pop_front() is called.
    01194        */
    01195       void
    01196       pop_front()
    01197       {
    01198     if (this->_M_impl._M_start._M_cur
    01199         != this->_M_impl._M_start._M_last - 1)
    01200       {
    01201         this->_M_impl.destroy(this->_M_impl._M_start._M_cur);
    01202         ++this->_M_impl._M_start._M_cur;
    01203       }
    01204     else
    01205       _M_pop_front_aux();
    01206       }
    01207
    01208       /**
    01209        *  @brief  Removes last element.
    01210        *
    01211        *  This is a typical stack operation.  It shrinks the %deque by one.
    01212        *
    01213        *  Note that no data is returned, and if the last element's data is
    01214        *  needed, it should be retrieved before pop_back() is called.
    01215        */
    01216       void
    01217       pop_back()
    01218       {
    01219     if (this->_M_impl._M_finish._M_cur
    01220         != this->_M_impl._M_finish._M_first)
    01221       {
    01222         --this->_M_impl._M_finish._M_cur;
    01223         this->_M_impl.destroy(this->_M_impl._M_finish._M_cur);
    01224       }
    01225     else
    01226       _M_pop_back_aux();
    01227       }
    01228
    01229 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    01230       /**
    01231        *  @brief  Inserts an object in %deque before specified iterator.
    01232        *  @param  position  An iterator into the %deque.
    01233        *  @param  args  Arguments.
    01234        *  @return  An iterator that points to the inserted data.
    01235        *
    01236        *  This function will insert an object of type T constructed
    01237        *  with T(std::forward<Args>(args)...) before the specified location.
    01238        */
    01239       template<typename... _Args>
    01240         iterator
    01241         emplace(iterator __position, _Args&&... __args);
    01242 #endif
    01243
    01244       /**
    01245        *  @brief  Inserts given value into %deque before specified iterator.
    01246        *  @param  position  An iterator into the %deque.
    01247        *  @param  x  Data to be inserted.
    01248        *  @return  An iterator that points to the inserted data.
    01249        *
    01250        *  This function will insert a copy of the given value before the
    01251        *  specified location.
    01252        */
    01253       iterator
    01254       insert(iterator __position, const value_type& __x);
    01255
    01256 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    01257       /**
    01258        *  @brief  Inserts given rvalue into %deque before specified iterator.
    01259        *  @param  position  An iterator into the %deque.
    01260        *  @param  x  Data to be inserted.
    01261        *  @return  An iterator that points to the inserted data.
    01262        *
    01263        *  This function will insert a copy of the given rvalue before the
    01264        *  specified location.
    01265        */
    01266       iterator
    01267       insert(iterator __position, value_type&& __x)
    01268       { return emplace(__position, std::move(__x)); }
    01269 #endif
    01270
    01271       /**
    01272        *  @brief  Inserts a number of copies of given data into the %deque.
    01273        *  @param  position  An iterator into the %deque.
    01274        *  @param  n  Number of elements to be inserted.
    01275        *  @param  x  Data to be inserted.
    01276        *
    01277        *  This function will insert a specified number of copies of the given
    01278        *  data before the location specified by @a position.
    01279        */
    01280       void
    01281       insert(iterator __position, size_type __n, const value_type& __x)
    01282       { _M_fill_insert(__position, __n, __x); }
    01283
    01284       /**
    01285        *  @brief  Inserts a range into the %deque.
    01286        *  @param  position  An iterator into the %deque.
    01287        *  @param  first  An input iterator.
    01288        *  @param  last   An input iterator.
    01289        *
    01290        *  This function will insert copies of the data in the range
    01291        *  [first,last) into the %deque before the location specified
    01292        *  by @a pos.  This is known as "range insert."
    01293        */
    01294       template<typename _InputIterator>
    01295         void
    01296         insert(iterator __position, _InputIterator __first,
    01297            _InputIterator __last)
    01298         {
    01299       // Check whether it's an integral type.  If so, it's not an iterator.
    01300       typedef typename std::__is_integer<_InputIterator>::__type _Integral;
    01301       _M_insert_dispatch(__position, __first, __last, _Integral());
    01302     }
    01303
    01304       /**
    01305        *  @brief  Remove element at given position.
    01306        *  @param  position  Iterator pointing to element to be erased.
    01307        *  @return  An iterator pointing to the next element (or end()).
    01308        *
    01309        *  This function will erase the element at the given position and thus
    01310        *  shorten the %deque by one.
    01311        *
    01312        *  The user is cautioned that
    01313        *  this function only erases the element, and that if the element is
    01314        *  itself a pointer, the pointed-to memory is not touched in any way.
    01315        *  Managing the pointer is the user's responsibility.
    01316        */
    01317       iterator
    01318       erase(iterator __position);
    01319
    01320       /**
    01321        *  @brief  Remove a range of elements.
    01322        *  @param  first  Iterator pointing to the first element to be erased.
    01323        *  @param  last  Iterator pointing to one past the last element to be
    01324        *                erased.
    01325        *  @return  An iterator pointing to the element pointed to by @a last
    01326        *           prior to erasing (or end()).
    01327        *
    01328        *  This function will erase the elements in the range [first,last) and
    01329        *  shorten the %deque accordingly.
    01330        *
    01331        *  The user is cautioned that
    01332        *  this function only erases the elements, and that if the elements
    01333        *  themselves are pointers, the pointed-to memory is not touched in any
    01334        *  way.  Managing the pointer is the user's responsibility.
    01335        */
    01336       iterator
    01337       erase(iterator __first, iterator __last);
    01338
    01339       /**
    01340        *  @brief  Swaps data with another %deque.
    01341        *  @param  x  A %deque of the same element and allocator types.
    01342        *
    01343        *  This exchanges the elements between two deques in constant time.
    01344        *  (Four pointers, so it should be quite fast.)
    01345        *  Note that the global std::swap() function is specialized such that
    01346        *  std::swap(d1,d2) will feed to this function.
    01347        */
    01348       void
    01349 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    01350       swap(deque&& __x)
    01351 #else
    01352       swap(deque& __x)
    01353 #endif
    01354       {
    01355     std::swap(this->_M_impl._M_start, __x._M_impl._M_start);
    01356     std::swap(this->_M_impl._M_finish, __x._M_impl._M_finish);
    01357     std::swap(this->_M_impl._M_map, __x._M_impl._M_map);
    01358     std::swap(this->_M_impl._M_map_size, __x._M_impl._M_map_size);
    01359
    01360     // _GLIBCXX_RESOLVE_LIB_DEFECTS
    01361     // 431. Swapping containers with unequal allocators.
    01362     std::__alloc_swap<_Tp_alloc_type>::_S_do_it(_M_get_Tp_allocator(),
    01363                             __x._M_get_Tp_allocator());
    01364       }
    01365
    01366       /**
    01367        *  Erases all the elements.  Note that this function only erases the
    01368        *  elements, and that if the elements themselves are pointers, the
    01369        *  pointed-to memory is not touched in any way.  Managing the pointer is
    01370        *  the user's responsibility.
    01371        */
    01372       void
    01373       clear()
    01374       { _M_erase_at_end(begin()); }
    01375
    01376     protected:
    01377       // Internal constructor functions follow.
    01378
    01379       // called by the range constructor to implement [23.1.1]/9
    01380
    01381       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    01382       // 438. Ambiguity in the "do the right thing" clause
    01383       template<typename _Integer>
    01384         void
    01385         _M_initialize_dispatch(_Integer __n, _Integer __x, __true_type)
    01386         {
    01387       _M_initialize_map(static_cast<size_type>(__n));
    01388       _M_fill_initialize(__x);
    01389     }
    01390
    01391       // called by the range constructor to implement [23.1.1]/9
    01392       template<typename _InputIterator>
    01393         void
    01394         _M_initialize_dispatch(_InputIterator __first, _InputIterator __last,
    01395                    __false_type)
    01396         {
    01397       typedef typename std::iterator_traits<_InputIterator>::
    01398         iterator_category _IterCategory;
    01399       _M_range_initialize(__first, __last, _IterCategory());
    01400     }
    01401
    01402       // called by the second initialize_dispatch above
    01403       //@{
    01404       /**
    01405        *  @brief Fills the deque with whatever is in [first,last).
    01406        *  @param  first  An input iterator.
    01407        *  @param  last  An input iterator.
    01408        *  @return   Nothing.
    01409        *
    01410        *  If the iterators are actually forward iterators (or better), then the
    01411        *  memory layout can be done all at once.  Else we move forward using
    01412        *  push_back on each value from the iterator.
    01413        */
    01414       template<typename _InputIterator>
    01415         void
    01416         _M_range_initialize(_InputIterator __first, _InputIterator __last,
    01417                 std::input_iterator_tag);
    01418
    01419       // called by the second initialize_dispatch above
    01420       template<typename _ForwardIterator>
    01421         void
    01422         _M_range_initialize(_ForwardIterator __first, _ForwardIterator __last,
    01423                 std::forward_iterator_tag);
    01424       //@}
    01425
    01426       /**
    01427        *  @brief Fills the %deque with copies of value.
    01428        *  @param  value  Initial value.
    01429        *  @return   Nothing.
    01430        *  @pre _M_start and _M_finish have already been initialized,
    01431        *  but none of the %deque's elements have yet been constructed.
    01432        *
    01433        *  This function is called only when the user provides an explicit size
    01434        *  (with or without an explicit exemplar value).
    01435        */
    01436       void
    01437       _M_fill_initialize(const value_type& __value);
    01438
    01439       // Internal assign functions follow.  The *_aux functions do the actual
    01440       // assignment work for the range versions.
    01441
    01442       // called by the range assign to implement [23.1.1]/9
    01443
    01444       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    01445       // 438. Ambiguity in the "do the right thing" clause
    01446       template<typename _Integer>
    01447         void
    01448         _M_assign_dispatch(_Integer __n, _Integer __val, __true_type)
    01449         { _M_fill_assign(__n, __val); }
    01450
    01451       // called by the range assign to implement [23.1.1]/9
    01452       template<typename _InputIterator>
    01453         void
    01454         _M_assign_dispatch(_InputIterator __first, _InputIterator __last,
    01455                __false_type)
    01456         {
    01457       typedef typename std::iterator_traits<_InputIterator>::
    01458         iterator_category _IterCategory;
    01459       _M_assign_aux(__first, __last, _IterCategory());
    01460     }
    01461
    01462       // called by the second assign_dispatch above
    01463       template<typename _InputIterator>
    01464         void
    01465         _M_assign_aux(_InputIterator __first, _InputIterator __last,
    01466               std::input_iterator_tag);
    01467
    01468       // called by the second assign_dispatch above
    01469       template<typename _ForwardIterator>
    01470         void
    01471         _M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
    01472               std::forward_iterator_tag)
    01473         {
    01474       const size_type __len = std::distance(__first, __last);
    01475       if (__len > size())
    01476         {
    01477           _ForwardIterator __mid = __first;
    01478           std::advance(__mid, size());
    01479           std::copy(__first, __mid, begin());
    01480           insert(end(), __mid, __last);
    01481         }
    01482       else
    01483         _M_erase_at_end(std::copy(__first, __last, begin()));
    01484     }
    01485
    01486       // Called by assign(n,t), and the range assign when it turns out
    01487       // to be the same thing.
    01488       void
    01489       _M_fill_assign(size_type __n, const value_type& __val)
    01490       {
    01491     if (__n > size())
    01492       {
    01493         std::fill(begin(), end(), __val);
    01494         insert(end(), __n - size(), __val);
    01495       }
    01496     else
    01497       {
    01498         _M_erase_at_end(begin() + difference_type(__n));
    01499         std::fill(begin(), end(), __val);
    01500       }
    01501       }
    01502
    01503       //@{
    01504       /// Helper functions for push_* and pop_*.
    01505 #ifndef __GXX_EXPERIMENTAL_CXX0X__
    01506       void _M_push_back_aux(const value_type&);
    01507
    01508       void _M_push_front_aux(const value_type&);
    01509 #else
    01510       template<typename... _Args>
    01511         void _M_push_back_aux(_Args&&... __args);
    01512
    01513       template<typename... _Args>
    01514         void _M_push_front_aux(_Args&&... __args);
    01515 #endif
    01516
    01517       void _M_pop_back_aux();
    01518
    01519       void _M_pop_front_aux();
    01520       //@}
    01521
    01522       // Internal insert functions follow.  The *_aux functions do the actual
    01523       // insertion work when all shortcuts fail.
    01524
    01525       // called by the range insert to implement [23.1.1]/9
    01526
    01527       // _GLIBCXX_RESOLVE_LIB_DEFECTS
    01528       // 438. Ambiguity in the "do the right thing" clause
    01529       template<typename _Integer>
    01530         void
    01531         _M_insert_dispatch(iterator __pos,
    01532                _Integer __n, _Integer __x, __true_type)
    01533         { _M_fill_insert(__pos, __n, __x); }
    01534
    01535       // called by the range insert to implement [23.1.1]/9
    01536       template<typename _InputIterator>
    01537         void
    01538         _M_insert_dispatch(iterator __pos,
    01539                _InputIterator __first, _InputIterator __last,
    01540                __false_type)
    01541         {
    01542       typedef typename std::iterator_traits<_InputIterator>::
    01543         iterator_category _IterCategory;
    01544           _M_range_insert_aux(__pos, __first, __last, _IterCategory());
    01545     }
    01546
    01547       // called by the second insert_dispatch above
    01548       template<typename _InputIterator>
    01549         void
    01550         _M_range_insert_aux(iterator __pos, _InputIterator __first,
    01551                 _InputIterator __last, std::input_iterator_tag);
    01552
    01553       // called by the second insert_dispatch above
    01554       template<typename _ForwardIterator>
    01555         void
    01556         _M_range_insert_aux(iterator __pos, _ForwardIterator __first,
    01557                 _ForwardIterator __last, std::forward_iterator_tag);
    01558
    01559       // Called by insert(p,n,x), and the range insert when it turns out to be
    01560       // the same thing.  Can use fill functions in optimal situations,
    01561       // otherwise passes off to insert_aux(p,n,x).
    01562       void
    01563       _M_fill_insert(iterator __pos, size_type __n, const value_type& __x);
    01564
    01565       // called by insert(p,x)
    01566 #ifndef __GXX_EXPERIMENTAL_CXX0X__
    01567       iterator
    01568       _M_insert_aux(iterator __pos, const value_type& __x);
    01569 #else
    01570       template<typename... _Args>
    01571         iterator
    01572         _M_insert_aux(iterator __pos, _Args&&... __args);
    01573 #endif
    01574
    01575       // called by insert(p,n,x) via fill_insert
    01576       void
    01577       _M_insert_aux(iterator __pos, size_type __n, const value_type& __x);
    01578
    01579       // called by range_insert_aux for forward iterators
    01580       template<typename _ForwardIterator>
    01581         void
    01582         _M_insert_aux(iterator __pos,
    01583               _ForwardIterator __first, _ForwardIterator __last,
    01584               size_type __n);
    01585
    01586
    01587       // Internal erase functions follow.
    01588
    01589       void
    01590       _M_destroy_data_aux(iterator __first, iterator __last);
    01591
    01592       // Called by ~deque().
    01593       // NB: Doesn't deallocate the nodes.
    01594       template<typename _Alloc1>
    01595         void
    01596         _M_destroy_data(iterator __first, iterator __last, const _Alloc1&)
    01597         { _M_destroy_data_aux(__first, __last); }
    01598
    01599       void
    01600       _M_destroy_data(iterator __first, iterator __last,
    01601               const std::allocator<_Tp>&)
    01602       {
    01603     if (!__has_trivial_destructor(value_type))
    01604       _M_destroy_data_aux(__first, __last);
    01605       }
    01606
    01607       // Called by erase(q1, q2).
    01608       void
    01609       _M_erase_at_begin(iterator __pos)
    01610       {
    01611     _M_destroy_data(begin(), __pos, _M_get_Tp_allocator());
    01612     _M_destroy_nodes(this->_M_impl._M_start._M_node, __pos._M_node);
    01613     this->_M_impl._M_start = __pos;
    01614       }
    01615
    01616       // Called by erase(q1, q2), resize(), clear(), _M_assign_aux,
    01617       // _M_fill_assign, operator=.
    01618       void
    01619       _M_erase_at_end(iterator __pos)
    01620       {
    01621     _M_destroy_data(__pos, end(), _M_get_Tp_allocator());
    01622     _M_destroy_nodes(__pos._M_node + 1,
    01623              this->_M_impl._M_finish._M_node + 1);
    01624     this->_M_impl._M_finish = __pos;
    01625       }
    01626
    01627       //@{
    01628       /// Memory-handling helpers for the previous internal insert functions.
    01629       iterator
    01630       _M_reserve_elements_at_front(size_type __n)
    01631       {
    01632     const size_type __vacancies = this->_M_impl._M_start._M_cur
    01633                                   - this->_M_impl._M_start._M_first;
    01634     if (__n > __vacancies)
    01635       _M_new_elements_at_front(__n - __vacancies);
    01636     return this->_M_impl._M_start - difference_type(__n);
    01637       }
    01638
    01639       iterator
    01640       _M_reserve_elements_at_back(size_type __n)
    01641       {
    01642     const size_type __vacancies = (this->_M_impl._M_finish._M_last
    01643                        - this->_M_impl._M_finish._M_cur) - 1;
    01644     if (__n > __vacancies)
    01645       _M_new_elements_at_back(__n - __vacancies);
    01646     return this->_M_impl._M_finish + difference_type(__n);
    01647       }
    01648
    01649       void
    01650       _M_new_elements_at_front(size_type __new_elements);
    01651
    01652       void
    01653       _M_new_elements_at_back(size_type __new_elements);
    01654       //@}
    01655
    01656
    01657       //@{
    01658       /**
    01659        *  @brief Memory-handling helpers for the major %map.
    01660        *
    01661        *  Makes sure the _M_map has space for new nodes.  Does not
    01662        *  actually add the nodes.  Can invalidate _M_map pointers.
    01663        *  (And consequently, %deque iterators.)
    01664        */
    01665       void
    01666       _M_reserve_map_at_back(size_type __nodes_to_add = 1)
    01667       {
    01668     if (__nodes_to_add + 1 > this->_M_impl._M_map_size
    01669         - (this->_M_impl._M_finish._M_node - this->_M_impl._M_map))
    01670       _M_reallocate_map(__nodes_to_add, false);
    01671       }
    01672
    01673       void
    01674       _M_reserve_map_at_front(size_type __nodes_to_add = 1)
    01675       {
    01676     if (__nodes_to_add > size_type(this->_M_impl._M_start._M_node
    01677                        - this->_M_impl._M_map))
    01678       _M_reallocate_map(__nodes_to_add, true);
    01679       }
    01680
    01681       void
    01682       _M_reallocate_map(size_type __nodes_to_add, bool __add_at_front);
    01683       //@}
    01684     };
    01685
    01686
    01687   /**
    01688    *  @brief  Deque equality comparison.
    01689    *  @param  x  A %deque.
    01690    *  @param  y  A %deque of the same type as @a x.
    01691    *  @return  True iff the size and elements of the deques are equal.
    01692    *
    01693    *  This is an equivalence relation.  It is linear in the size of the
    01694    *  deques.  Deques are considered equivalent if their sizes are equal,
    01695    *  and if corresponding elements compare equal.
    01696   */
    01697   template<typename _Tp, typename _Alloc>
    01698     inline bool
    01699     operator==(const deque<_Tp, _Alloc>& __x,
    01700                          const deque<_Tp, _Alloc>& __y)
    01701     { return __x.size() == __y.size()
    01702              && std::equal(__x.begin(), __x.end(), __y.begin()); }
    01703
    01704   /**
    01705    *  @brief  Deque ordering relation.
    01706    *  @param  x  A %deque.
    01707    *  @param  y  A %deque of the same type as @a x.
    01708    *  @return  True iff @a x is lexicographically less than @a y.
    01709    *
    01710    *  This is a total ordering relation.  It is linear in the size of the
    01711    *  deques.  The elements must be comparable with @c <.
    01712    *
    01713    *  See std::lexicographical_compare() for how the determination is made.
    01714   */
    01715   template<typename _Tp, typename _Alloc>
    01716     inline bool
    01717     operator<(const deque<_Tp, _Alloc>& __x,
    01718           const deque<_Tp, _Alloc>& __y)
    01719     { return std::lexicographical_compare(__x.begin(), __x.end(),
    01720                       __y.begin(), __y.end()); }
    01721
    01722   /// Based on operator==
    01723   template<typename _Tp, typename _Alloc>
    01724     inline bool
    01725     operator!=(const deque<_Tp, _Alloc>& __x,
    01726            const deque<_Tp, _Alloc>& __y)
    01727     { return !(__x == __y); }
    01728
    01729   /// Based on operator<
    01730   template<typename _Tp, typename _Alloc>
    01731     inline bool
    01732     operator>(const deque<_Tp, _Alloc>& __x,
    01733           const deque<_Tp, _Alloc>& __y)
    01734     { return __y < __x; }
    01735
    01736   /// Based on operator<
    01737   template<typename _Tp, typename _Alloc>
    01738     inline bool
    01739     operator<=(const deque<_Tp, _Alloc>& __x,
    01740            const deque<_Tp, _Alloc>& __y)
    01741     { return !(__y < __x); }
    01742
    01743   /// Based on operator<
    01744   template<typename _Tp, typename _Alloc>
    01745     inline bool
    01746     operator>=(const deque<_Tp, _Alloc>& __x,
    01747            const deque<_Tp, _Alloc>& __y)
    01748     { return !(__x < __y); }
    01749
    01750   /// See std::deque::swap().
    01751   template<typename _Tp, typename _Alloc>
    01752     inline void
    01753     swap(deque<_Tp,_Alloc>& __x, deque<_Tp,_Alloc>& __y)
    01754     { __x.swap(__y); }
    01755
    01756 #ifdef __GXX_EXPERIMENTAL_CXX0X__
    01757   template<typename _Tp, typename _Alloc>
    01758     inline void
    01759     swap(deque<_Tp,_Alloc>&& __x, deque<_Tp,_Alloc>& __y)
    01760     { __x.swap(__y); }
    01761
    01762   template<typename _Tp, typename _Alloc>
    01763     inline void
    01764     swap(deque<_Tp,_Alloc>& __x, deque<_Tp,_Alloc>&& __y)
    01765     { __x.swap(__y); }
    01766 #endif
    01767
    01768 _GLIBCXX_END_NESTED_NAMESPACE
    01769
    01770 #endif /* _STL_DEQUE_H */