OSDN Git Service

2010-08-05 Paolo Carlini <paolo.carlini@oracle.com>
[pf3gnuchains/gcc-fork.git] / libstdc++-v3 / include / bits / stl_iterator.h
index ae8b088..105469a 100644 (file)
@@ -1,3 +1,28 @@
+// Iterators -*- C++ -*-
+
+// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
+// Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
 /*
  *
  * Copyright (c) 1994
  * purpose.  It is provided "as is" without express or implied warranty.
  */
 
-/* NOTE: This is an internal header file, included by other STL headers.
- *   You should not attempt to use it directly.
+/** @file stl_iterator.h
+ *  This is an internal header file, included by other library headers.
+ *  You should not attempt to use it directly.
+ *
+ *  This file implements reverse_iterator, back_insert_iterator,
+ *  front_insert_iterator, insert_iterator, __normal_iterator, and their
+ *  supporting functions and overloaded operators.
  */
 
-#ifndef __SGI_STL_INTERNAL_ITERATOR_H
-#define __SGI_STL_INTERNAL_ITERATOR_H
-
-__STL_BEGIN_NAMESPACE
-
-
-template <class _Container>
-class back_insert_iterator {
-protected:
-  _Container* container;
-public:
-  typedef _Container          container_type;
-  typedef output_iterator_tag iterator_category;
-  typedef void                value_type;
-  typedef void                difference_type;
-  typedef void                pointer;
-  typedef void                reference;
-
-  explicit back_insert_iterator(_Container& __x) : container(&__x) {}
-  back_insert_iterator<_Container>&
-  operator=(const typename _Container::value_type& __value) { 
-    container->push_back(__value);
-    return *this;
-  }
-  back_insert_iterator<_Container>& operator*() { return *this; }
-  back_insert_iterator<_Container>& operator++() { return *this; }
-  back_insert_iterator<_Container>& operator++(int) { return *this; }
-};
-
-#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
-
-template <class _Container>
-inline output_iterator_tag
-iterator_category(const back_insert_iterator<_Container>&)
-{
-  return output_iterator_tag();
-}
-
-#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
-
-template <class _Container>
-inline back_insert_iterator<_Container> back_inserter(_Container& __x) {
-  return back_insert_iterator<_Container>(__x);
-}
-
-template <class _Container>
-class front_insert_iterator {
-protected:
-  _Container* container;
-public:
-  typedef _Container          container_type;
-  typedef output_iterator_tag iterator_category;
-  typedef void                value_type;
-  typedef void                difference_type;
-  typedef void                pointer;
-  typedef void                reference;
-
-  explicit front_insert_iterator(_Container& __x) : container(&__x) {}
-  front_insert_iterator<_Container>&
-  operator=(const typename _Container::value_type& __value) { 
-    container->push_front(__value);
-    return *this;
-  }
-  front_insert_iterator<_Container>& operator*() { return *this; }
-  front_insert_iterator<_Container>& operator++() { return *this; }
-  front_insert_iterator<_Container>& operator++(int) { return *this; }
-};
-
-#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
-
-template <class _Container>
-inline output_iterator_tag
-iterator_category(const front_insert_iterator<_Container>&)
-{
-  return output_iterator_tag();
-}
-
-#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
-
-template <class _Container>
-inline front_insert_iterator<_Container> front_inserter(_Container& __x) {
-  return front_insert_iterator<_Container>(__x);
-}
-
-template <class _Container>
-class insert_iterator {
-protected:
-  _Container* container;
-  typename _Container::iterator iter;
-public:
-  typedef _Container          container_type;
-  typedef output_iterator_tag iterator_category;
-  typedef void                value_type;
-  typedef void                difference_type;
-  typedef void                pointer;
-  typedef void                reference;
-
-  insert_iterator(_Container& __x, typename _Container::iterator __i) 
-    : container(&__x), iter(__i) {}
-  insert_iterator<_Container>&
-  operator=(const typename _Container::value_type& __value) { 
-    iter = container->insert(iter, __value);
-    ++iter;
-    return *this;
-  }
-  insert_iterator<_Container>& operator*() { return *this; }
-  insert_iterator<_Container>& operator++() { return *this; }
-  insert_iterator<_Container>& operator++(int) { return *this; }
-};
-
-#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
-
-template <class _Container>
-inline output_iterator_tag
-iterator_category(const insert_iterator<_Container>&)
-{
-  return output_iterator_tag();
-}
-
-#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
-
-template <class _Container, class _Iterator>
-inline 
-insert_iterator<_Container> inserter(_Container& __x, _Iterator __i)
-{
-  typedef typename _Container::iterator __iter;
-  return insert_iterator<_Container>(__x, __iter(__i));
-}
-
-template <class _BidirectionalIterator, class _Tp, class _Reference = _Tp&, 
-          class _Distance = ptrdiff_t> 
-class reverse_bidirectional_iterator {
-  typedef reverse_bidirectional_iterator<_BidirectionalIterator, _Tp, 
-                                         _Reference, _Distance>  _Self;
-protected:
-  _BidirectionalIterator current;
-public:
-  typedef bidirectional_iterator_tag iterator_category;
-  typedef _Tp                        value_type;
-  typedef _Distance                  difference_type;
-  typedef _Tp*                       pointer;
-  typedef _Reference                 reference;
-
-  reverse_bidirectional_iterator() {}
-  explicit reverse_bidirectional_iterator(_BidirectionalIterator __x)
-    : current(__x) {}
-  _BidirectionalIterator base() const { return current; }
-  _Reference operator*() const {
-    _BidirectionalIterator __tmp = current;
-    return *--__tmp;
-  }
-#ifndef __SGI_STL_NO_ARROW_OPERATOR
-  pointer operator->() const { return &(operator*()); }
-#endif /* __SGI_STL_NO_ARROW_OPERATOR */
-  _Self& operator++() {
-    --current;
-    return *this;
-  }
-  _Self operator++(int) {
-    _Self __tmp = *this;
-    --current;
-    return __tmp;
-  }
-  _Self& operator--() {
-    ++current;
-    return *this;
-  }
-  _Self operator--(int) {
-    _Self __tmp = *this;
-    ++current;
-    return __tmp;
-  }
-};
-
-#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
-
-template <class _BidirectionalIterator, class _Tp, class _Reference, 
-          class _Distance>
-inline bidirectional_iterator_tag
-iterator_category(const reverse_bidirectional_iterator<_BidirectionalIterator,
-                                                       _Tp, _Reference, 
-                                                       _Distance>&) 
-{
-  return bidirectional_iterator_tag();
-}
-
-template <class _BidirectionalIterator, class _Tp, class _Reference, 
-          class _Distance>
-inline _Tp*
-value_type(const reverse_bidirectional_iterator<_BidirectionalIterator, _Tp,
-                                               _Reference, _Distance>&)
-{
-  return (_Tp*) 0;
-}
-
-template <class _BidirectionalIterator, class _Tp, class _Reference, 
-          class _Distance>
-inline _Distance*
-distance_type(const reverse_bidirectional_iterator<_BidirectionalIterator, 
-                                                   _Tp,
-                                                   _Reference, _Distance>&)
-{
-  return (_Distance*) 0;
-}
-
-#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
-
-template <class _BiIter, class _Tp, class _Ref, class _Distance>
-inline bool operator==(
-    const reverse_bidirectional_iterator<_BiIter, _Tp, _Ref, _Distance>& __x, 
-    const reverse_bidirectional_iterator<_BiIter, _Tp, _Ref, _Distance>& __y)
-{
-  return __x.base() == __y.base();
-}
-
-#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
-
-template <class _BiIter, class _Tp, class _Ref, class _Distance>
-inline bool operator!=(
-    const reverse_bidirectional_iterator<_BiIter, _Tp, _Ref, _Distance>& __x, 
-    const reverse_bidirectional_iterator<_BiIter, _Tp, _Ref, _Distance>& __y)
-{
-  return !(__x == __y);
-}
-
-#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */
-
-
-#ifdef __STL_CLASS_PARTIAL_SPECIALIZATION
-
-// This is the new version of reverse_iterator, as defined in the
-//  draft C++ standard.  It relies on the iterator_traits template,
-//  which in turn relies on partial specialization.  The class
-//  reverse_bidirectional_iterator is no longer part of the draft
-//  standard, but it is retained for backward compatibility.
-
-template <class _Iterator>
-class reverse_iterator 
-{
-protected:
-  _Iterator current;
-public:
-  typedef typename iterator_traits<_Iterator>::iterator_category
-          iterator_category;
-  typedef typename iterator_traits<_Iterator>::value_type
-          value_type;
-  typedef typename iterator_traits<_Iterator>::difference_type
-          difference_type;
-  typedef typename iterator_traits<_Iterator>::pointer
-          pointer;
-  typedef typename iterator_traits<_Iterator>::reference
-          reference;
-
-  typedef _Iterator iterator_type;
-  typedef reverse_iterator<_Iterator> _Self;
-
-public:
-  reverse_iterator() {}
-  explicit reverse_iterator(iterator_type __x) : current(__x) {}
-
-  reverse_iterator(const _Self& __x) : current(__x.current) {}
-#ifdef __STL_MEMBER_TEMPLATES
-  template <class _Iter>
-  reverse_iterator(const reverse_iterator<_Iter>& __x)
-    : current(__x.base()) {}
-#endif /* __STL_MEMBER_TEMPLATES */
-    
-  iterator_type base() const { return current; }
-  reference operator*() const {
-    _Iterator __tmp = current;
-    return *--__tmp;
-  }
-#ifndef __SGI_STL_NO_ARROW_OPERATOR
-  pointer operator->() const { return &(operator*()); }
-#endif /* __SGI_STL_NO_ARROW_OPERATOR */
-
-  _Self& operator++() {
-    --current;
-    return *this;
-  }
-  _Self operator++(int) {
-    _Self __tmp = *this;
-    --current;
-    return __tmp;
-  }
-  _Self& operator--() {
-    ++current;
-    return *this;
-  }
-  _Self operator--(int) {
-    _Self __tmp = *this;
-    ++current;
-    return __tmp;
-  }
-
-  _Self operator+(difference_type __n) const {
-    return _Self(current - __n);
-  }
-  _Self& operator+=(difference_type __n) {
-    current -= __n;
-    return *this;
-  }
-  _Self operator-(difference_type __n) const {
-    return _Self(current + __n);
-  }
-  _Self& operator-=(difference_type __n) {
-    current += __n;
-    return *this;
-  }
-  reference operator[](difference_type __n) const { return *(*this + __n); }  
-}; 
-template <class _Iterator>
-inline bool operator==(const reverse_iterator<_Iterator>& __x, 
-                       const reverse_iterator<_Iterator>& __y) {
-  return __x.base() == __y.base();
-}
-
-template <class _Iterator>
-inline bool operator<(const reverse_iterator<_Iterator>& __x, 
-                      const reverse_iterator<_Iterator>& __y) {
-  return __y.base() < __x.base();
-}
-
-#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
-
-template <class _Iterator>
-inline bool operator!=(const reverse_iterator<_Iterator>& __x, 
-                       const reverse_iterator<_Iterator>& __y) {
-  return !(__x == __y);
-}
-
-template <class _Iterator>
-inline bool operator>(const reverse_iterator<_Iterator>& __x, 
-                      const reverse_iterator<_Iterator>& __y) {
-  return __y < __x;
-}
-
-template <class _Iterator>
-inline bool operator<=(const reverse_iterator<_Iterator>& __x, 
-                       const reverse_iterator<_Iterator>& __y) {
-  return !(__y < __x);
-}
-
-template <class _Iterator>
-inline bool operator>=(const reverse_iterator<_Iterator>& __x, 
-                      const reverse_iterator<_Iterator>& __y) {
-  return !(__x < __y);
-}
-
-#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */
-
-template <class _Iterator>
-inline typename reverse_iterator<_Iterator>::difference_type
-operator-(const reverse_iterator<_Iterator>& __x, 
-          const reverse_iterator<_Iterator>& __y) {
-  return __y.base() - __x.base();
-}
-
-template <class _Iterator>
-inline reverse_iterator<_Iterator> 
-operator+(typename reverse_iterator<_Iterator>::difference_type __n,
-          const reverse_iterator<_Iterator>& __x) {
-  return reverse_iterator<_Iterator>(__x.base() - __n);
-}
-
-#else /* __STL_CLASS_PARTIAL_SPECIALIZATION */
-
-// This is the old version of reverse_iterator, as found in the original
-//  HP STL.  It does not use partial specialization.
-
-template <class _RandomAccessIterator, class _Tp, class _Reference = _Tp&,
-          class _Distance = ptrdiff_t> 
-class reverse_iterator {
-  typedef reverse_iterator<_RandomAccessIterator, _Tp, _Reference, _Distance>
-        _Self;
-protected:
-  _RandomAccessIterator current;
-public:
-  typedef random_access_iterator_tag iterator_category;
-  typedef _Tp                        value_type;
-  typedef _Distance                  difference_type;
-  typedef _Tp*                       pointer;
-  typedef _Reference                 reference;
-
-  reverse_iterator() {}
-  explicit reverse_iterator(_RandomAccessIterator __x) : current(__x) {}
-  _RandomAccessIterator base() const { return current; }
-  _Reference operator*() const { return *(current - 1); }
-#ifndef __SGI_STL_NO_ARROW_OPERATOR
-  pointer operator->() const { return &(operator*()); }
-#endif /* __SGI_STL_NO_ARROW_OPERATOR */
-  _Self& operator++() {
-    --current;
-    return *this;
-  }
-  _Self operator++(int) {
-    _Self __tmp = *this;
-    --current;
-    return __tmp;
-  }
-  _Self& operator--() {
-    ++current;
-    return *this;
-  }
-  _Self operator--(int) {
-    _Self __tmp = *this;
-    ++current;
-    return __tmp;
-  }
-  _Self operator+(_Distance __n) const {
-    return _Self(current - __n);
-  }
-  _Self& operator+=(_Distance __n) {
-    current -= __n;
-    return *this;
-  }
-  _Self operator-(_Distance __n) const {
-    return _Self(current + __n);
-  }
-  _Self& operator-=(_Distance __n) {
-    current += __n;
-    return *this;
-  }
-  _Reference operator[](_Distance __n) const { return *(*this + __n); }
-};
-
-template <class _RandomAccessIterator, class _Tp, 
-          class _Reference, class _Distance>
-inline random_access_iterator_tag
-iterator_category(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                         _Reference, _Distance>&)
-{
-  return random_access_iterator_tag();
-}
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline _Tp* value_type(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                              _Reference, _Distance>&)
-{
-  return (_Tp*) 0;
-}
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline _Distance* 
-distance_type(const reverse_iterator<_RandomAccessIterator, 
-                                     _Tp, _Reference, _Distance>&)
-{
-  return (_Distance*) 0;
-}
-
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline bool 
-operator==(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                  _Reference, _Distance>& __x, 
-           const reverse_iterator<_RandomAccessIterator, _Tp,
-                                  _Reference, _Distance>& __y)
-{
-  return __x.base() == __y.base();
-}
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline bool 
-operator<(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                 _Reference, _Distance>& __x, 
-          const reverse_iterator<_RandomAccessIterator, _Tp,
-                                 _Reference, _Distance>& __y)
-{
-  return __y.base() < __x.base();
-}
-
-#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline bool 
-operator!=(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                  _Reference, _Distance>& __x, 
-           const reverse_iterator<_RandomAccessIterator, _Tp,
-                                  _Reference, _Distance>& __y) {
-  return !(__x == __y);
-}
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline bool 
-operator>(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                 _Reference, _Distance>& __x, 
-          const reverse_iterator<_RandomAccessIterator, _Tp,
-                                 _Reference, _Distance>& __y) {
-  return __y < __x;
-}
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline bool 
-operator<=(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                  _Reference, _Distance>& __x, 
-           const reverse_iterator<_RandomAccessIterator, _Tp,
-                                  _Reference, _Distance>& __y) {
-  return !(__y < __x);
-}
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline bool 
-operator>=(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                  _Reference, _Distance>& __x, 
-           const reverse_iterator<_RandomAccessIterator, _Tp,
-                                  _Reference, _Distance>& __y) {
-  return !(__x < __y);
-}
-
-#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */
-
-template <class _RandomAccessIterator, class _Tp,
-          class _Reference, class _Distance>
-inline _Distance 
-operator-(const reverse_iterator<_RandomAccessIterator, _Tp,
-                                 _Reference, _Distance>& __x, 
-          const reverse_iterator<_RandomAccessIterator, _Tp,
-                                 _Reference, _Distance>& __y)
-{
-  return __y.base() - __x.base();
-}
-
-template <class _RandAccIter, class _Tp, class _Ref, class _Dist>
-inline reverse_iterator<_RandAccIter, _Tp, _Ref, _Dist> 
-operator+(_Dist __n,
-          const reverse_iterator<_RandAccIter, _Tp, _Ref, _Dist>& __x)
-{
-  return reverse_iterator<_RandAccIter, _Tp, _Ref, _Dist>(__x.base() - __n);
-}
-
-#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
-
-// istream_iterator and ostream_iterator look very different if we're
-// using new, templatized iostreams than if we're using the old cfront
-// version.
-
-#ifdef __STL_USE_NEW_IOSTREAMS
-
-template <class _Tp, 
-          class _CharT = char, class _Traits = char_traits<_CharT>,
-          class _Dist = ptrdiff_t> 
-class istream_iterator {
-public:
-  typedef _CharT                         char_type;
-  typedef _Traits                        traits_type;
-  typedef basic_istream<_CharT, _Traits> istream_type;
-
-  typedef input_iterator_tag             iterator_category;
-  typedef _Tp                            value_type;
-  typedef _Dist                          difference_type;
-  typedef const _Tp*                     pointer;
-  typedef const _Tp&                     reference;
-
-  istream_iterator() : _M_stream(0), _M_ok(false) {}
-  istream_iterator(istream_type& __s) : _M_stream(&__s) { _M_read(); }
-
-  reference operator*() const { return _M_value; }
-  pointer operator->() const { return &(operator*()); }
-
-  istream_iterator& operator++() { 
-    _M_read(); 
-    return *this;
-  }
-  istream_iterator operator++(int)  {
-    istream_iterator __tmp = *this;
-    _M_read();
-    return __tmp;
-  }
-
-  bool _M_equal(const istream_iterator& __x) const
-    { return (_M_ok == __x._M_ok) && (!_M_ok || _M_stream == __x._M_stream); }
-
-private:
-  istream_type* _M_stream;
-  _Tp _M_value;
-  bool _M_ok;
-
-  void _M_read() {
-    _M_ok = (_M_stream && *_M_stream) ? true : false;
-    if (_M_ok) {
-      *_M_stream >> _M_value;
-      _M_ok = *_M_stream ? true : false;
+#ifndef _STL_ITERATOR_H
+#define _STL_ITERATOR_H 1
+
+#include <bits/cpp_type_traits.h>
+#include <ext/type_traits.h>
+#include <bits/move.h>
+
+_GLIBCXX_BEGIN_NAMESPACE(std)
+
+  /**
+   * @addtogroup iterators
+   * @{
+   */
+
+  // 24.4.1 Reverse iterators
+  /**
+   *  Bidirectional and random access iterators have corresponding reverse
+   *  %iterator adaptors that iterate through the data structure in the
+   *  opposite direction.  They have the same signatures as the corresponding
+   *  iterators.  The fundamental relation between a reverse %iterator and its
+   *  corresponding %iterator @c i is established by the identity:
+   *  @code
+   *      &*(reverse_iterator(i)) == &*(i - 1)
+   *  @endcode
+   *
+   *  <em>This mapping is dictated by the fact that while there is always a
+   *  pointer past the end of an array, there might not be a valid pointer
+   *  before the beginning of an array.</em> [24.4.1]/1,2
+   *
+   *  Reverse iterators can be tricky and surprising at first.  Their
+   *  semantics make sense, however, and the trickiness is a side effect of
+   *  the requirement that the iterators must be safe.
+  */
+  template<typename _Iterator>
+    class reverse_iterator
+    : public iterator<typename iterator_traits<_Iterator>::iterator_category,
+                     typename iterator_traits<_Iterator>::value_type,
+                     typename iterator_traits<_Iterator>::difference_type,
+                     typename iterator_traits<_Iterator>::pointer,
+                      typename iterator_traits<_Iterator>::reference>
+    {
+    protected:
+      _Iterator current;
+
+      typedef iterator_traits<_Iterator>               __traits_type;
+
+    public:
+      typedef _Iterator                                        iterator_type;
+      typedef typename __traits_type::difference_type  difference_type;
+      typedef typename __traits_type::pointer          pointer;
+      typedef typename __traits_type::reference                reference;
+
+      /**
+       *  The default constructor default-initializes member @p current.
+       *  If it is a pointer, that means it is zero-initialized.
+      */
+      // _GLIBCXX_RESOLVE_LIB_DEFECTS
+      // 235 No specification of default ctor for reverse_iterator
+      reverse_iterator() : current() { }
+
+      /**
+       *  This %iterator will move in the opposite direction that @p x does.
+      */
+      explicit
+      reverse_iterator(iterator_type __x) : current(__x) { }
+
+      /**
+       *  The copy constructor is normal.
+      */
+      reverse_iterator(const reverse_iterator& __x)
+      : current(__x.current) { }
+
+      /**
+       *  A reverse_iterator across other types can be copied in the normal
+       *  fashion.
+      */
+      template<typename _Iter>
+        reverse_iterator(const reverse_iterator<_Iter>& __x)
+       : current(__x.base()) { }
+
+      /**
+       *  @return  @c current, the %iterator used for underlying work.
+      */
+      iterator_type
+      base() const
+      { return current; }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reference
+      operator*() const
+      {
+       _Iterator __tmp = current;
+       return *--__tmp;
+      }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      pointer
+      operator->() const
+      { return &(operator*()); }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reverse_iterator&
+      operator++()
+      {
+       --current;
+       return *this;
+      }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reverse_iterator
+      operator++(int)
+      {
+       reverse_iterator __tmp = *this;
+       --current;
+       return __tmp;
+      }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reverse_iterator&
+      operator--()
+      {
+       ++current;
+       return *this;
+      }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reverse_iterator
+      operator--(int)
+      {
+       reverse_iterator __tmp = *this;
+       ++current;
+       return __tmp;
+      }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reverse_iterator
+      operator+(difference_type __n) const
+      { return reverse_iterator(current - __n); }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reverse_iterator&
+      operator+=(difference_type __n)
+      {
+       current -= __n;
+       return *this;
+      }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reverse_iterator
+      operator-(difference_type __n) const
+      { return reverse_iterator(current + __n); }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reverse_iterator&
+      operator-=(difference_type __n)
+      {
+       current += __n;
+       return *this;
+      }
+
+      /**
+       *  @return  TODO
+       *
+       *  @doctodo
+      */
+      reference
+      operator[](difference_type __n) const
+      { return *(*this + __n); }
+    };
+
+  //@{
+  /**
+   *  @param  x  A %reverse_iterator.
+   *  @param  y  A %reverse_iterator.
+   *  @return  A simple bool.
+   *
+   *  Reverse iterators forward many operations to their underlying base()
+   *  iterators.  Others are implemented in terms of one another.
+   *
+  */
+  template<typename _Iterator>
+    inline bool
+    operator==(const reverse_iterator<_Iterator>& __x,
+              const reverse_iterator<_Iterator>& __y)
+    { return __x.base() == __y.base(); }
+
+  template<typename _Iterator>
+    inline bool
+    operator<(const reverse_iterator<_Iterator>& __x,
+             const reverse_iterator<_Iterator>& __y)
+    { return __y.base() < __x.base(); }
+
+  template<typename _Iterator>
+    inline bool
+    operator!=(const reverse_iterator<_Iterator>& __x,
+              const reverse_iterator<_Iterator>& __y)
+    { return !(__x == __y); }
+
+  template<typename _Iterator>
+    inline bool
+    operator>(const reverse_iterator<_Iterator>& __x,
+             const reverse_iterator<_Iterator>& __y)
+    { return __y < __x; }
+
+  template<typename _Iterator>
+    inline bool
+    operator<=(const reverse_iterator<_Iterator>& __x,
+              const reverse_iterator<_Iterator>& __y)
+    { return !(__y < __x); }
+
+  template<typename _Iterator>
+    inline bool
+    operator>=(const reverse_iterator<_Iterator>& __x,
+              const reverse_iterator<_Iterator>& __y)
+    { return !(__x < __y); }
+
+  template<typename _Iterator>
+    inline typename reverse_iterator<_Iterator>::difference_type
+    operator-(const reverse_iterator<_Iterator>& __x,
+             const reverse_iterator<_Iterator>& __y)
+    { return __y.base() - __x.base(); }
+
+  template<typename _Iterator>
+    inline reverse_iterator<_Iterator>
+    operator+(typename reverse_iterator<_Iterator>::difference_type __n,
+             const reverse_iterator<_Iterator>& __x)
+    { return reverse_iterator<_Iterator>(__x.base() - __n); }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // DR 280. Comparison of reverse_iterator to const reverse_iterator.
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator==(const reverse_iterator<_IteratorL>& __x,
+              const reverse_iterator<_IteratorR>& __y)
+    { return __x.base() == __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator<(const reverse_iterator<_IteratorL>& __x,
+             const reverse_iterator<_IteratorR>& __y)
+    { return __y.base() < __x.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator!=(const reverse_iterator<_IteratorL>& __x,
+              const reverse_iterator<_IteratorR>& __y)
+    { return !(__x == __y); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator>(const reverse_iterator<_IteratorL>& __x,
+             const reverse_iterator<_IteratorR>& __y)
+    { return __y < __x; }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator<=(const reverse_iterator<_IteratorL>& __x,
+              const reverse_iterator<_IteratorR>& __y)
+    { return !(__y < __x); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator>=(const reverse_iterator<_IteratorL>& __x,
+              const reverse_iterator<_IteratorR>& __y)
+    { return !(__x < __y); }
+
+  template<typename _IteratorL, typename _IteratorR>
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+    // DR 685.
+    inline auto
+    operator-(const reverse_iterator<_IteratorL>& __x,
+             const reverse_iterator<_IteratorR>& __y)
+    -> decltype(__y.base() - __x.base())
+#else
+    inline typename reverse_iterator<_IteratorL>::difference_type
+    operator-(const reverse_iterator<_IteratorL>& __x,
+             const reverse_iterator<_IteratorR>& __y)
+#endif
+    { return __y.base() - __x.base(); }
+  //@}
+
+  // 24.4.2.2.1 back_insert_iterator
+  /**
+   *  @brief  Turns assignment into insertion.
+   *
+   *  These are output iterators, constructed from a container-of-T.
+   *  Assigning a T to the iterator appends it to the container using
+   *  push_back.
+   *
+   *  Tip:  Using the back_inserter function to create these iterators can
+   *  save typing.
+  */
+  template<typename _Container>
+    class back_insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+    protected:
+      _Container* container;
+
+    public:
+      /// A nested typedef for the type of whatever container you used.
+      typedef _Container          container_type;
+
+      /// The only way to create this %iterator is with a container.
+      explicit
+      back_insert_iterator(_Container& __x) : container(&__x) { }
+
+      /**
+       *  @param  value  An instance of whatever type
+       *                 container_type::const_reference is; presumably a
+       *                 reference-to-const T for container<T>.
+       *  @return  This %iterator, for chained operations.
+       *
+       *  This kind of %iterator doesn't really have a @a position in the
+       *  container (you can think of the position as being permanently at
+       *  the end, if you like).  Assigning a value to the %iterator will
+       *  always append the value to the end of the container.
+      */
+      back_insert_iterator&
+      operator=(typename _Container::const_reference __value)
+      {
+       container->push_back(__value);
+       return *this;
+      }
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      back_insert_iterator&
+      operator=(typename _Container::value_type&& __value)
+      {
+       container->push_back(std::move(__value));
+       return *this;
+      }
+#endif
+
+      /// Simply returns *this.
+      back_insert_iterator&
+      operator*()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      back_insert_iterator&
+      operator++()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      back_insert_iterator
+      operator++(int)
+      { return *this; }
+    };
+
+  /**
+   *  @param  x  A container of arbitrary type.
+   *  @return  An instance of back_insert_iterator working on @p x.
+   *
+   *  This wrapper function helps in creating back_insert_iterator instances.
+   *  Typing the name of the %iterator requires knowing the precise full
+   *  type of the container, which can be tedious and impedes generic
+   *  programming.  Using this function lets you take advantage of automatic
+   *  template parameter deduction, making the compiler match the correct
+   *  types for you.
+  */
+  template<typename _Container>
+    inline back_insert_iterator<_Container>
+    back_inserter(_Container& __x)
+    { return back_insert_iterator<_Container>(__x); }
+
+  /**
+   *  @brief  Turns assignment into insertion.
+   *
+   *  These are output iterators, constructed from a container-of-T.
+   *  Assigning a T to the iterator prepends it to the container using
+   *  push_front.
+   *
+   *  Tip:  Using the front_inserter function to create these iterators can
+   *  save typing.
+  */
+  template<typename _Container>
+    class front_insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+    protected:
+      _Container* container;
+
+    public:
+      /// A nested typedef for the type of whatever container you used.
+      typedef _Container          container_type;
+
+      /// The only way to create this %iterator is with a container.
+      explicit front_insert_iterator(_Container& __x) : container(&__x) { }
+
+      /**
+       *  @param  value  An instance of whatever type
+       *                 container_type::const_reference is; presumably a
+       *                 reference-to-const T for container<T>.
+       *  @return  This %iterator, for chained operations.
+       *
+       *  This kind of %iterator doesn't really have a @a position in the
+       *  container (you can think of the position as being permanently at
+       *  the front, if you like).  Assigning a value to the %iterator will
+       *  always prepend the value to the front of the container.
+      */
+      front_insert_iterator&
+      operator=(typename _Container::const_reference __value)
+      {
+       container->push_front(__value);
+       return *this;
+      }
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      front_insert_iterator&
+      operator=(typename _Container::value_type&& __value)
+      {
+       container->push_front(std::move(__value));
+       return *this;
+      }
+#endif
+
+      /// Simply returns *this.
+      front_insert_iterator&
+      operator*()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      front_insert_iterator&
+      operator++()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      front_insert_iterator
+      operator++(int)
+      { return *this; }
+    };
+
+  /**
+   *  @param  x  A container of arbitrary type.
+   *  @return  An instance of front_insert_iterator working on @p x.
+   *
+   *  This wrapper function helps in creating front_insert_iterator instances.
+   *  Typing the name of the %iterator requires knowing the precise full
+   *  type of the container, which can be tedious and impedes generic
+   *  programming.  Using this function lets you take advantage of automatic
+   *  template parameter deduction, making the compiler match the correct
+   *  types for you.
+  */
+  template<typename _Container>
+    inline front_insert_iterator<_Container>
+    front_inserter(_Container& __x)
+    { return front_insert_iterator<_Container>(__x); }
+
+  /**
+   *  @brief  Turns assignment into insertion.
+   *
+   *  These are output iterators, constructed from a container-of-T.
+   *  Assigning a T to the iterator inserts it in the container at the
+   *  %iterator's position, rather than overwriting the value at that
+   *  position.
+   *
+   *  (Sequences will actually insert a @e copy of the value before the
+   *  %iterator's position.)
+   *
+   *  Tip:  Using the inserter function to create these iterators can
+   *  save typing.
+  */
+  template<typename _Container>
+    class insert_iterator
+    : public iterator<output_iterator_tag, void, void, void, void>
+    {
+    protected:
+      _Container* container;
+      typename _Container::iterator iter;
+
+    public:
+      /// A nested typedef for the type of whatever container you used.
+      typedef _Container          container_type;
+
+      /**
+       *  The only way to create this %iterator is with a container and an
+       *  initial position (a normal %iterator into the container).
+      */
+      insert_iterator(_Container& __x, typename _Container::iterator __i)
+      : container(&__x), iter(__i) {}
+
+      /**
+       *  @param  value  An instance of whatever type
+       *                 container_type::const_reference is; presumably a
+       *                 reference-to-const T for container<T>.
+       *  @return  This %iterator, for chained operations.
+       *
+       *  This kind of %iterator maintains its own position in the
+       *  container.  Assigning a value to the %iterator will insert the
+       *  value into the container at the place before the %iterator.
+       *
+       *  The position is maintained such that subsequent assignments will
+       *  insert values immediately after one another.  For example,
+       *  @code
+       *     // vector v contains A and Z
+       *
+       *     insert_iterator i (v, ++v.begin());
+       *     i = 1;
+       *     i = 2;
+       *     i = 3;
+       *
+       *     // vector v contains A, 1, 2, 3, and Z
+       *  @endcode
+      */
+      insert_iterator&
+      operator=(typename _Container::const_reference __value)
+      {
+       iter = container->insert(iter, __value);
+       ++iter;
+       return *this;
+      }
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+      insert_iterator&
+      operator=(typename _Container::value_type&& __value)
+      {
+       iter = container->insert(iter, std::move(__value));
+       ++iter;
+       return *this;
+      }
+#endif
+
+      /// Simply returns *this.
+      insert_iterator&
+      operator*()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      insert_iterator&
+      operator++()
+      { return *this; }
+
+      /// Simply returns *this.  (This %iterator does not @a move.)
+      insert_iterator&
+      operator++(int)
+      { return *this; }
+    };
+
+  /**
+   *  @param  x  A container of arbitrary type.
+   *  @return  An instance of insert_iterator working on @p x.
+   *
+   *  This wrapper function helps in creating insert_iterator instances.
+   *  Typing the name of the %iterator requires knowing the precise full
+   *  type of the container, which can be tedious and impedes generic
+   *  programming.  Using this function lets you take advantage of automatic
+   *  template parameter deduction, making the compiler match the correct
+   *  types for you.
+  */
+  template<typename _Container, typename _Iterator>
+    inline insert_iterator<_Container>
+    inserter(_Container& __x, _Iterator __i)
+    {
+      return insert_iterator<_Container>(__x,
+                                        typename _Container::iterator(__i));
     }
-  }
-};
-
-template <class _Tp, class _CharT, class _Traits, class _Dist>
-inline bool 
-operator==(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
-           const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y) {
-  return __x._M_equal(__y);
-}
-
-#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
-
-template <class _Tp, class _CharT, class _Traits, class _Dist>
-inline bool 
-operator!=(const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __x,
-           const istream_iterator<_Tp, _CharT, _Traits, _Dist>& __y) {
-  return !__x._M_equal(__y);
-}
-
-#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */
-
-template <class _Tp,
-          class _CharT = char, class _Traits = char_traits<_CharT> >
-class ostream_iterator {
-public:
-  typedef _CharT                         char_type;
-  typedef _Traits                        traits_type;
-  typedef basic_ostream<_CharT, _Traits> ostream_type;
-
-  typedef output_iterator_tag            iterator_category;
-  typedef void                           value_type;
-  typedef void                           difference_type;
-  typedef void                           pointer;
-  typedef void                           reference;
-
-  ostream_iterator(ostream_type& __s) : _M_stream(&__s), _M_string(0) {}
-  ostream_iterator(ostream_type& __s, const _CharT* __c) 
-    : _M_stream(&__s), _M_string(__c)  {}
-  ostream_iterator<_Tp>& operator=(const _Tp& __value) { 
-    *_M_stream << __value;
-    if (_M_string) *_M_stream << _M_string;
-    return *this;
-  }
-  ostream_iterator<_Tp>& operator*() { return *this; }
-  ostream_iterator<_Tp>& operator++() { return *this; } 
-  ostream_iterator<_Tp>& operator++(int) { return *this; } 
-private:
-  ostream_type* _M_stream;
-  const _CharT* _M_string;
-};
-
-// The default template argument is declared in iosfwd
-
-// We do not read any characters until operator* is called.  The first
-// time operator* is called, it calls getc.  Subsequent calls to getc 
-// return a cached character, and calls to operator++ use snextc.  Before
-// operator* or operator++ has been called, _M_is_initialized is false.
-template<class _CharT, class _Traits>
-class istreambuf_iterator
-  : public iterator<input_iterator_tag, _CharT,
-                    typename _Traits::off_type, _CharT*, _CharT&>
-{
-public:
-  typedef _CharT                           char_type;
-  typedef _Traits                          traits_type;
-  typedef typename _Traits::int_type       int_type;
-  typedef basic_streambuf<_CharT, _Traits> streambuf_type;
-  typedef basic_istream<_CharT, _Traits>   istream_type;
-
-public:
-  istreambuf_iterator(streambuf_type* __p = 0) { this->_M_init(__p); }
-  istreambuf_iterator(istream_type& __is) { this->_M_init(__is.rdbuf()); }
-
-  char_type operator*() const 
-    { return _M_is_initialized ? _M_c : _M_dereference_aux(); }
-
-  istreambuf_iterator& operator++() { this->_M_nextc(); return *this; }
-  istreambuf_iterator  operator++(int) {
-    if (!_M_is_initialized)
-      _M_postincr_aux();
-    istreambuf_iterator __tmp = *this;
-    this->_M_nextc();
-    return __tmp;
-  }
-
-  bool equal(const istreambuf_iterator& __i) const {
-    return this->_M_is_initialized && __i._M_is_initialized
-      ? this->_M_eof == __i._M_eof
-      : this->_M_equal_aux(__i);
-  }
-
-private:
-  void _M_init(streambuf_type* __p) {
-    _M_buf = __p;
-    _M_eof = !__p;
-    _M_is_initialized = _M_eof;
-  }
-
-  char_type _M_dereference_aux() const;
-  bool _M_equal_aux(const istreambuf_iterator&) const;
-  void _M_postincr_aux();
-
-  void _M_nextc() {
-    int_type __c = _M_buf->snextc();
-    _M_c = traits_type::to_char_type(__c);    
-    _M_eof = traits_type::eq_int_type(__c, traits_type::eof());
-    _M_is_initialized = true;
-  }
-
-  void _M_getc() const {
-    int_type __c = _M_buf->sgetc();
-    _M_c = traits_type::to_char_type(__c);
-    _M_eof = traits_type::eq_int_type(__c, traits_type::eof());
-    _M_is_initialized = true;
-  }
-
-private:
-  streambuf_type* _M_buf;
-  mutable _CharT _M_c;
-  mutable bool _M_eof : 1;
-  mutable bool _M_is_initialized : 1;
-};
-
-template<class _CharT, class _Traits>
-_CharT istreambuf_iterator<_CharT, _Traits>::_M_dereference_aux() const
-{
-  this->_M_getc();
-  return _M_c;
-}
-
-template<class _CharT, class _Traits>
-bool istreambuf_iterator<_CharT, _Traits>
-  ::_M_equal_aux(const istreambuf_iterator& __i) const
-{
-  if (!this->_M_is_initialized)
-    this->_M_getc();
-  if (!__i._M_is_initialized)
-    __i._M_getc();
-
-  return this->_M_eof == __i._M_eof;
-}
-
-template<class _CharT, class _Traits>
-void istreambuf_iterator<_CharT, _Traits>::_M_postincr_aux()
-{
-  this->_M_getc();
-}
-
-template<class _CharT, class _Traits>
-inline bool operator==(const istreambuf_iterator<_CharT, _Traits>& __x,
-                       const istreambuf_iterator<_CharT, _Traits>& __y) {
-  return __x.equal(__y);
-}
-
-#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
-
-template<class _CharT, class _Traits>
-inline bool operator!=(const istreambuf_iterator<_CharT, _Traits>& __x,
-                       const istreambuf_iterator<_CharT, _Traits>& __y) {
-  return !__x.equal(__y);
-}
-
-#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */
-
-// The default template argument is declared in iosfwd
-template<class _CharT, class _Traits>
-class ostreambuf_iterator
-  : public iterator<output_iterator_tag, void, void, void, void>
-{
-public:
-  typedef _CharT                           char_type;
-  typedef _Traits                          traits_type;
-  typedef typename _Traits::int_type       int_type;
-  typedef basic_streambuf<_CharT, _Traits> streambuf_type;
-  typedef basic_ostream<_CharT, _Traits>   ostream_type;
-
-public:
-  ostreambuf_iterator(streambuf_type* __buf) : _M_buf(__buf), _M_ok(__buf) {}
-  ostreambuf_iterator(ostream_type& __o)
-    : _M_buf(__o.rdbuf()), _M_ok(__o.rdbuf() != 0) {}
-
-  ostreambuf_iterator& operator=(char_type __c) {
-    _M_ok = _M_ok && !traits_type::eq_int_type(_M_buf->sputc(__c),
-                                               traits_type::eof());
-    return *this;
-  }    
-  
-  ostreambuf_iterator& operator*()     { return *this; }
-  ostreambuf_iterator& operator++()    { return *this; }
-  ostreambuf_iterator& operator++(int) { return *this; }
-
-  bool failed() const { return !_M_ok; }
-
-private:
-  streambuf_type* _M_buf;
-  bool _M_ok;
-};
-
-#else /* __STL_USE_NEW_IOSTREAMS */
-
-template <class _Tp, class _Dist = ptrdiff_t> class istream_iterator;
-
-template <class _Tp, class _Dist>
-inline bool operator==(const istream_iterator<_Tp, _Dist>&,
-                       const istream_iterator<_Tp, _Dist>&);
-
-template <class _Tp, class _Dist>
-class istream_iterator {
-#ifdef __STL_TEMPLATE_FRIENDS
-  template <class _T1, class _D1>
-  friend bool operator==(const istream_iterator<_T1, _D1>&,
-                         const istream_iterator<_T1, _D1>&);
-#else /* __STL_TEMPLATE_FRIENDS */
-  friend bool __STD_QUALIFIER
-  operator== __STL_NULL_TMPL_ARGS (const istream_iterator&,
-                                   const istream_iterator&);
-#endif /* __STL_TEMPLATE_FRIENDS */
-
-protected:
-  istream* _M_stream;
-  _Tp _M_value;
-  bool _M_end_marker;
-  void _M_read() {
-    _M_end_marker = (*_M_stream) ? true : false;
-    if (_M_end_marker) *_M_stream >> _M_value;
-    _M_end_marker = (*_M_stream) ? true : false;
-  }
-public:
-  typedef input_iterator_tag  iterator_category;
-  typedef _Tp                 value_type;
-  typedef _Dist               difference_type;
-  typedef const _Tp*          pointer;
-  typedef const _Tp&          reference;
-
-  istream_iterator() : _M_stream(&cin), _M_end_marker(false) {}
-  istream_iterator(istream& __s) : _M_stream(&__s) { _M_read(); }
-  reference operator*() const { return _M_value; }
-#ifndef __SGI_STL_NO_ARROW_OPERATOR
-  pointer operator->() const { return &(operator*()); }
-#endif /* __SGI_STL_NO_ARROW_OPERATOR */
-  istream_iterator<_Tp, _Dist>& operator++() { 
-    _M_read(); 
-    return *this;
-  }
-  istream_iterator<_Tp, _Dist> operator++(int)  {
-    istream_iterator<_Tp, _Dist> __tmp = *this;
-    _M_read();
-    return __tmp;
-  }
-};
-
-#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
-
-template <class _Tp, class _Dist>
-inline input_iterator_tag 
-iterator_category(const istream_iterator<_Tp, _Dist>&)
-{
-  return input_iterator_tag();
-}
-
-template <class _Tp, class _Dist>
-inline _Tp* 
-value_type(const istream_iterator<_Tp, _Dist>&) { return (_Tp*) 0; }
-
-template <class _Tp, class _Dist>
-inline _Dist* 
-distance_type(const istream_iterator<_Tp, _Dist>&) { return (_Dist*)0; }
-
-#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
-
-template <class _Tp, class _Distance>
-inline bool operator==(const istream_iterator<_Tp, _Distance>& __x,
-                       const istream_iterator<_Tp, _Distance>& __y) {
-  return (__x._M_stream == __y._M_stream &&
-          __x._M_end_marker == __y._M_end_marker) ||
-         __x._M_end_marker == false && __y._M_end_marker == false;
-}
-
-#ifdef __STL_FUNCTION_TMPL_PARTIAL_ORDER
-
-template <class _Tp, class _Distance>
-inline bool operator!=(const istream_iterator<_Tp, _Distance>& __x,
-                       const istream_iterator<_Tp, _Distance>& __y) {
-  return !(__x == __y);
-}
-
-#endif /* __STL_FUNCTION_TMPL_PARTIAL_ORDER */
-
-template <class _Tp>
-class ostream_iterator {
-protected:
-  ostream* _M_stream;
-  const char* _M_string;
-public:
-  typedef output_iterator_tag iterator_category;
-  typedef void                value_type;
-  typedef void                difference_type;
-  typedef void                pointer;
-  typedef void                reference;
-
-  ostream_iterator(ostream& __s) : _M_stream(&__s), _M_string(0) {}
-  ostream_iterator(ostream& __s, const char* __c) 
-    : _M_stream(&__s), _M_string(__c)  {}
-  ostream_iterator<_Tp>& operator=(const _Tp& __value) { 
-    *_M_stream << __value;
-    if (_M_string) *_M_stream << _M_string;
-    return *this;
-  }
-  ostream_iterator<_Tp>& operator*() { return *this; }
-  ostream_iterator<_Tp>& operator++() { return *this; } 
-  ostream_iterator<_Tp>& operator++(int) { return *this; } 
-};
-
-#ifndef __STL_CLASS_PARTIAL_SPECIALIZATION
-
-template <class _Tp>
-inline output_iterator_tag 
-iterator_category(const ostream_iterator<_Tp>&) {
-  return output_iterator_tag();
-}
-
-#endif /* __STL_CLASS_PARTIAL_SPECIALIZATION */
-
-#endif /* __STL_USE_NEW_IOSTREAMS */
-
-// This iterator adapter is 'normal' in the sense that it does not
-// change the semantics of any of the operators of its itererator
-// parameter.  Its primary purpose is to convert an iterator that is
-// not a class, e.g. a pointer, into an iterator that is a class.
-// The _Container parameter exists solely so that different containers
-// using this template can instantiate different types, even if the
-// _Iterator parameter is the same.
-template<typename _Iterator, typename _Container>
-class __normal_iterator
-  : public iterator<iterator_traits<_Iterator>::iterator_category,
-                    iterator_traits<_Iterator>::value_type,
-                    iterator_traits<_Iterator>::difference_type,
-                    iterator_traits<_Iterator>::pointer,
-                    iterator_traits<_Iterator>::reference>
-{
-
-protected:
-  _Iterator _M_current;
-
-public:
-  typedef __normal_iterator<_Iterator, _Container> normal_iterator_type;
-  typedef iterator_traits<_Iterator>                   __traits_type;
-  typedef typename __traits_type::iterator_category    iterator_category;
-  typedef typename __traits_type::value_type           value_type;
-  typedef typename __traits_type::difference_type      difference_type;
-  typedef typename __traits_type::pointer              pointer;
-  typedef typename __traits_type::reference            reference;
-
-  __normal_iterator() : _M_current(_Iterator()) { }
-
-  explicit __normal_iterator(const _Iterator& __i) : _M_current(__i) { }
-
-  // Allow iterator to const_iterator conversion
-  template<typename _Iter>
-  inline __normal_iterator(const __normal_iterator<_Iter, _Container>& __i)
-    : _M_current(__i.base()) { }
-
-  // Forward iterator requirements
-  reference
-  operator*() const { return *_M_current; }
 
-  pointer
-  operator->() const { return _M_current; }
+  // @} group iterators
+
+_GLIBCXX_END_NAMESPACE
+
+_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx)
+
+  // This iterator adapter is @a normal in the sense that it does not
+  // change the semantics of any of the operators of its iterator
+  // parameter.  Its primary purpose is to convert an iterator that is
+  // not a class, e.g. a pointer, into an iterator that is a class.
+  // The _Container parameter exists solely so that different containers
+  // using this template can instantiate different types, even if the
+  // _Iterator parameter is the same.
+  using std::iterator_traits;
+  using std::iterator;
+  template<typename _Iterator, typename _Container>
+    class __normal_iterator
+    {
+    protected:
+      _Iterator _M_current;
+
+      typedef iterator_traits<_Iterator>               __traits_type;
+
+    public:
+      typedef _Iterator                                        iterator_type;
+      typedef typename __traits_type::iterator_category iterator_category;
+      typedef typename __traits_type::value_type       value_type;
+      typedef typename __traits_type::difference_type  difference_type;
+      typedef typename __traits_type::reference        reference;
+      typedef typename __traits_type::pointer          pointer;
+
+      __normal_iterator() : _M_current(_Iterator()) { }
+
+      explicit
+      __normal_iterator(const _Iterator& __i) : _M_current(__i) { }
+
+      // Allow iterator to const_iterator conversion
+      template<typename _Iter>
+        __normal_iterator(const __normal_iterator<_Iter,
+                         typename __enable_if<
+              (std::__are_same<_Iter, typename _Container::pointer>::__value),
+                     _Container>::__type>& __i)
+        : _M_current(__i.base()) { }
+
+      // Forward iterator requirements
+      reference
+      operator*() const
+      { return *_M_current; }
+
+      pointer
+      operator->() const
+      { return _M_current; }
+
+      __normal_iterator&
+      operator++()
+      {
+       ++_M_current;
+       return *this;
+      }
+
+      __normal_iterator
+      operator++(int)
+      { return __normal_iterator(_M_current++); }
+
+      // Bidirectional iterator requirements
+      __normal_iterator&
+      operator--()
+      {
+       --_M_current;
+       return *this;
+      }
+
+      __normal_iterator
+      operator--(int)
+      { return __normal_iterator(_M_current--); }
+
+      // Random access iterator requirements
+      reference
+      operator[](const difference_type& __n) const
+      { return _M_current[__n]; }
+
+      __normal_iterator&
+      operator+=(const difference_type& __n)
+      { _M_current += __n; return *this; }
+
+      __normal_iterator
+      operator+(const difference_type& __n) const
+      { return __normal_iterator(_M_current + __n); }
+
+      __normal_iterator&
+      operator-=(const difference_type& __n)
+      { _M_current -= __n; return *this; }
+
+      __normal_iterator
+      operator-(const difference_type& __n) const
+      { return __normal_iterator(_M_current - __n); }
+
+      const _Iterator&
+      base() const
+      { return _M_current; }
+    };
+
+  // Note: In what follows, the left- and right-hand-side iterators are
+  // allowed to vary in types (conceptually in cv-qualification) so that
+  // comparison between cv-qualified and non-cv-qualified iterators be
+  // valid.  However, the greedy and unfriendly operators in std::rel_ops
+  // will make overload resolution ambiguous (when in scope) if we don't
+  // provide overloads whose operands are of the same type.  Can someone
+  // remind me what generic programming is about? -- Gaby
 
-  normal_iterator_type&
-  operator++() { ++_M_current; return *this; }
-
-  normal_iterator_type
-  operator++(int) { return __normal_iterator(_M_current++); }
-
-  // Bidirectional iterator requirements
-  normal_iterator_type&
-  operator--() { --_M_current; return *this; }
-
-  normal_iterator_type
-  operator--(int) { return __normal_iterator(_M_current--); }
+  // Forward iterator requirements
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    inline bool
+    operator==(const __normal_iterator<_IteratorL, _Container>& __lhs,
+              const __normal_iterator<_IteratorR, _Container>& __rhs)
+    { return __lhs.base() == __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    inline bool
+    operator==(const __normal_iterator<_Iterator, _Container>& __lhs,
+              const __normal_iterator<_Iterator, _Container>& __rhs)
+    { return __lhs.base() == __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    inline bool
+    operator!=(const __normal_iterator<_IteratorL, _Container>& __lhs,
+              const __normal_iterator<_IteratorR, _Container>& __rhs)
+    { return __lhs.base() != __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    inline bool
+    operator!=(const __normal_iterator<_Iterator, _Container>& __lhs,
+              const __normal_iterator<_Iterator, _Container>& __rhs)
+    { return __lhs.base() != __rhs.base(); }
 
   // Random access iterator requirements
-  reference
-  operator[](const difference_type& __n) const
-  { return _M_current[__n]; }
-
-  normal_iterator_type&
-  operator+=(const difference_type& __n)
-  { _M_current += __n; return *this; }
-
-  normal_iterator_type
-  operator+(const difference_type& __n) const
-  { return __normal_iterator(_M_current + __n); }
-
-  normal_iterator_type&
-  operator-=(const difference_type& __n)
-  { _M_current -= __n; return *this; }
-
-  normal_iterator_type
-  operator-(const difference_type& __n) const
-  { return __normal_iterator(_M_current - __n); }
-
-  difference_type
-  operator-(const normal_iterator_type& __i) const
-  { return _M_current - __i._M_current; }
-
-  const _Iterator& 
-  base() const { return _M_current; }
-};
-
-// forward iterator requirements
-
-template<typename _IteratorL, typename _IteratorR, typename _Container>
-inline bool
-operator==(const __normal_iterator<_IteratorL, _Container>& __lhs,
-          const __normal_iterator<_IteratorR, _Container>& __rhs)
-{ return __lhs.base() == __rhs.base(); }
-
-template<typename _IteratorL, typename _IteratorR, typename _Container>
-inline bool
-operator!=(const __normal_iterator<_IteratorL, _Container>& __lhs,
-          const __normal_iterator<_IteratorR, _Container>& __rhs)
-{ return !(__lhs == __rhs); }
-
-// random access iterator requirements
-
-template<typename _IteratorL, typename _IteratorR, typename _Container>
-inline bool 
-operator<(const __normal_iterator<_IteratorL, _Container>& __lhs,
-         const __normal_iterator<_IteratorR, _Container>& __rhs)
-{ return __lhs.base() < __rhs.base(); }
-
-template<typename _IteratorL, typename _IteratorR, typename _Container>
-inline bool
-operator>(const __normal_iterator<_IteratorL, _Container>& __lhs,
-         const __normal_iterator<_IteratorR, _Container>& __rhs)
-{ return __rhs < __lhs; }
-
-template<typename _IteratorL, typename _IteratorR, typename _Container>
-inline bool
-operator<=(const __normal_iterator<_IteratorL, _Container>& __lhs,
-          const __normal_iterator<_IteratorR, _Container>& __rhs)
-{ return !(__rhs < __lhs); }
-
-template<typename _IteratorL, typename _IteratorR, typename _Container>
-inline bool
-operator>=(const __normal_iterator<_IteratorL, _Container>& __lhs,
-          const __normal_iterator<_IteratorR, _Container>& __rhs)
-{ return !(__lhs < __rhs); }
-
-template<typename _Iterator, typename _Container>
-inline __normal_iterator<_Iterator, _Container>
-operator+(__normal_iterator<_Iterator, _Container>::difference_type __n,
-          const __normal_iterator<_Iterator, _Container>& __i)
-{ return __normal_iterator<_Iterator, _Container>(__i.base() + __n); }
-
-__STL_END_NAMESPACE
-
-#endif /* __SGI_STL_INTERNAL_ITERATOR_H */
-
-// Local Variables:
-// mode:C++
-// End:
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    inline bool
+    operator<(const __normal_iterator<_IteratorL, _Container>& __lhs,
+             const __normal_iterator<_IteratorR, _Container>& __rhs)
+    { return __lhs.base() < __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    inline bool
+    operator<(const __normal_iterator<_Iterator, _Container>& __lhs,
+             const __normal_iterator<_Iterator, _Container>& __rhs)
+    { return __lhs.base() < __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    inline bool
+    operator>(const __normal_iterator<_IteratorL, _Container>& __lhs,
+             const __normal_iterator<_IteratorR, _Container>& __rhs)
+    { return __lhs.base() > __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    inline bool
+    operator>(const __normal_iterator<_Iterator, _Container>& __lhs,
+             const __normal_iterator<_Iterator, _Container>& __rhs)
+    { return __lhs.base() > __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    inline bool
+    operator<=(const __normal_iterator<_IteratorL, _Container>& __lhs,
+              const __normal_iterator<_IteratorR, _Container>& __rhs)
+    { return __lhs.base() <= __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    inline bool
+    operator<=(const __normal_iterator<_Iterator, _Container>& __lhs,
+              const __normal_iterator<_Iterator, _Container>& __rhs)
+    { return __lhs.base() <= __rhs.base(); }
+
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+    inline bool
+    operator>=(const __normal_iterator<_IteratorL, _Container>& __lhs,
+              const __normal_iterator<_IteratorR, _Container>& __rhs)
+    { return __lhs.base() >= __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    inline bool
+    operator>=(const __normal_iterator<_Iterator, _Container>& __lhs,
+              const __normal_iterator<_Iterator, _Container>& __rhs)
+    { return __lhs.base() >= __rhs.base(); }
+
+  // _GLIBCXX_RESOLVE_LIB_DEFECTS
+  // According to the resolution of DR179 not only the various comparison
+  // operators but also operator- must accept mixed iterator/const_iterator
+  // parameters.
+  template<typename _IteratorL, typename _IteratorR, typename _Container>
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+    // DR 685.
+    inline auto
+    operator-(const __normal_iterator<_IteratorL, _Container>& __lhs,
+             const __normal_iterator<_IteratorR, _Container>& __rhs)
+    -> decltype(__lhs.base() - __rhs.base())
+#else
+    inline typename __normal_iterator<_IteratorL, _Container>::difference_type
+    operator-(const __normal_iterator<_IteratorL, _Container>& __lhs,
+             const __normal_iterator<_IteratorR, _Container>& __rhs)
+#endif
+    { return __lhs.base() - __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    inline typename __normal_iterator<_Iterator, _Container>::difference_type
+    operator-(const __normal_iterator<_Iterator, _Container>& __lhs,
+             const __normal_iterator<_Iterator, _Container>& __rhs)
+    { return __lhs.base() - __rhs.base(); }
+
+  template<typename _Iterator, typename _Container>
+    inline __normal_iterator<_Iterator, _Container>
+    operator+(typename __normal_iterator<_Iterator, _Container>::difference_type
+             __n, const __normal_iterator<_Iterator, _Container>& __i)
+    { return __normal_iterator<_Iterator, _Container>(__i.base() + __n); }
+
+_GLIBCXX_END_NAMESPACE
+
+#ifdef __GXX_EXPERIMENTAL_CXX0X__
+
+_GLIBCXX_BEGIN_NAMESPACE(std)
+
+  /**
+   * @addtogroup iterators
+   * @{
+   */
+
+  // 24.4.3  Move iterators
+  /**
+   *  Class template move_iterator is an iterator adapter with the same
+   *  behavior as the underlying iterator except that its dereference
+   *  operator implicitly converts the value returned by the underlying
+   *  iterator's dereference operator to an rvalue reference.  Some
+   *  generic algorithms can be called with move iterators to replace
+   *  copying with moving.
+   */
+  template<typename _Iterator>
+    class move_iterator
+    {
+    protected:
+      _Iterator _M_current;
+
+      typedef iterator_traits<_Iterator>               __traits_type;
+
+    public:
+      typedef _Iterator                                        iterator_type;
+      typedef typename __traits_type::iterator_category iterator_category;
+      typedef typename __traits_type::value_type       value_type;
+      typedef typename __traits_type::difference_type  difference_type;
+      // NB: DR 680.
+      typedef _Iterator                                        pointer;
+      typedef value_type&&                             reference;
+
+      move_iterator()
+      : _M_current() { }
+
+      explicit
+      move_iterator(iterator_type __i)
+      : _M_current(__i) { }
+
+      template<typename _Iter>
+       move_iterator(const move_iterator<_Iter>& __i)
+       : _M_current(__i.base()) { }
+
+      iterator_type
+      base() const
+      { return _M_current; }
+
+      reference
+      operator*() const
+      { return std::move(*_M_current); }
+
+      pointer
+      operator->() const
+      { return _M_current; }
+
+      move_iterator&
+      operator++()
+      {
+       ++_M_current;
+       return *this;
+      }
+
+      move_iterator
+      operator++(int)
+      {
+       move_iterator __tmp = *this;
+       ++_M_current;
+       return __tmp;
+      }
+
+      move_iterator&
+      operator--()
+      {
+       --_M_current;
+       return *this;
+      }
+
+      move_iterator
+      operator--(int)
+      {
+       move_iterator __tmp = *this;
+       --_M_current;
+       return __tmp;
+      }
+
+      move_iterator
+      operator+(difference_type __n) const
+      { return move_iterator(_M_current + __n); }
+
+      move_iterator&
+      operator+=(difference_type __n)
+      {
+       _M_current += __n;
+       return *this;
+      }
+
+      move_iterator
+      operator-(difference_type __n) const
+      { return move_iterator(_M_current - __n); }
+    
+      move_iterator&
+      operator-=(difference_type __n)
+      { 
+       _M_current -= __n;
+       return *this;
+      }
+
+      reference
+      operator[](difference_type __n) const
+      { return std::move(_M_current[__n]); }
+    };
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator==(const move_iterator<_IteratorL>& __x,
+              const move_iterator<_IteratorR>& __y)
+    { return __x.base() == __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator!=(const move_iterator<_IteratorL>& __x,
+              const move_iterator<_IteratorR>& __y)
+    { return !(__x == __y); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator<(const move_iterator<_IteratorL>& __x,
+             const move_iterator<_IteratorR>& __y)
+    { return __x.base() < __y.base(); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator<=(const move_iterator<_IteratorL>& __x,
+              const move_iterator<_IteratorR>& __y)
+    { return !(__y < __x); }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator>(const move_iterator<_IteratorL>& __x,
+             const move_iterator<_IteratorR>& __y)
+    { return __y < __x; }
+
+  template<typename _IteratorL, typename _IteratorR>
+    inline bool
+    operator>=(const move_iterator<_IteratorL>& __x,
+              const move_iterator<_IteratorR>& __y)
+    { return !(__x < __y); }
+
+  // DR 685.
+  template<typename _IteratorL, typename _IteratorR>
+    inline auto
+    operator-(const move_iterator<_IteratorL>& __x,
+             const move_iterator<_IteratorR>& __y)
+    -> decltype(__x.base() - __y.base())
+    { return __x.base() - __y.base(); }
+
+  template<typename _Iterator>
+    inline move_iterator<_Iterator>
+    operator+(typename move_iterator<_Iterator>::difference_type __n,
+             const move_iterator<_Iterator>& __x)
+    { return __x + __n; }
+
+  template<typename _Iterator>
+    inline move_iterator<_Iterator>
+    make_move_iterator(const _Iterator& __i)
+    { return move_iterator<_Iterator>(__i); }
+
+  // @} group iterators
+
+_GLIBCXX_END_NAMESPACE
+
+#define _GLIBCXX_MAKE_MOVE_ITERATOR(_Iter) std::make_move_iterator(_Iter)
+#else
+#define _GLIBCXX_MAKE_MOVE_ITERATOR(_Iter) (_Iter)
+#endif // __GXX_EXPERIMENTAL_CXX0X__
+
+#endif