1 // Functions used by iterators -*- C++ -*-
3 // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
4 // Free Software Foundation, Inc.
6 // This file is part of the GNU ISO C++ Library. This library is free
7 // software; you can redistribute it and/or modify it under the
8 // terms of the GNU General Public License as published by the
9 // Free Software Foundation; either version 3, or (at your option)
12 // This library is distributed in the hope that it will be useful,
13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 // GNU General Public License for more details.
17 // Under Section 7 of GPL version 3, you are granted additional
18 // permissions described in the GCC Runtime Library Exception, version
19 // 3.1, as published by the Free Software Foundation.
21 // You should have received a copy of the GNU General Public License and
22 // a copy of the GCC Runtime Library Exception along with this program;
23 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
24 // <http://www.gnu.org/licenses/>.
29 * Hewlett-Packard Company
31 * Permission to use, copy, modify, distribute and sell this software
32 * and its documentation for any purpose is hereby granted without fee,
33 * provided that the above copyright notice appear in all copies and
34 * that both that copyright notice and this permission notice appear
35 * in supporting documentation. Hewlett-Packard Company makes no
36 * representations about the suitability of this software for any
37 * purpose. It is provided "as is" without express or implied warranty.
40 * Copyright (c) 1996-1998
41 * Silicon Graphics Computer Systems, Inc.
43 * Permission to use, copy, modify, distribute and sell this software
44 * and its documentation for any purpose is hereby granted without fee,
45 * provided that the above copyright notice appear in all copies and
46 * that both that copyright notice and this permission notice appear
47 * in supporting documentation. Silicon Graphics makes no
48 * representations about the suitability of this software for any
49 * purpose. It is provided "as is" without express or implied warranty.
52 /** @file bits/stl_iterator_base_funcs.h
53 * This is an internal header file, included by other library headers.
54 * Do not attempt to use it directly. @headername{iterator}
56 * This file contains all of the general iterator-related utility
57 * functions, such as distance() and advance().
60 #ifndef _STL_ITERATOR_BASE_FUNCS_H
61 #define _STL_ITERATOR_BASE_FUNCS_H 1
63 #pragma GCC system_header
65 #include <bits/concept_check.h>
67 _GLIBCXX_BEGIN_NAMESPACE(std
)
69 template<typename _InputIterator
>
70 inline typename iterator_traits
<_InputIterator
>::difference_type
71 __distance(_InputIterator __first
, _InputIterator __last
,
74 // concept requirements
75 __glibcxx_function_requires(_InputIteratorConcept
<_InputIterator
>)
77 typename iterator_traits
<_InputIterator
>::difference_type __n
= 0;
78 while (__first
!= __last
)
86 template<typename _RandomAccessIterator
>
87 inline typename iterator_traits
<_RandomAccessIterator
>::difference_type
88 __distance(_RandomAccessIterator __first
, _RandomAccessIterator __last
,
89 random_access_iterator_tag
)
91 // concept requirements
92 __glibcxx_function_requires(_RandomAccessIteratorConcept
<
93 _RandomAccessIterator
>)
94 return __last
- __first
;
98 * @brief A generalization of pointer arithmetic.
99 * @param first An input iterator.
100 * @param last An input iterator.
101 * @return The distance between them.
103 * Returns @c n such that first + n == last. This requires that @p last
104 * must be reachable from @p first. Note that @c n may be negative.
106 * For random access iterators, this uses their @c + and @c - operations
107 * and are constant time. For other %iterator classes they are linear time.
109 template<typename _InputIterator
>
110 inline typename iterator_traits
<_InputIterator
>::difference_type
111 distance(_InputIterator __first
, _InputIterator __last
)
113 // concept requirements -- taken care of in __distance
114 return std::__distance(__first
, __last
,
115 std::__iterator_category(__first
));
118 template<typename _InputIterator
, typename _Distance
>
120 __advance(_InputIterator
& __i
, _Distance __n
, input_iterator_tag
)
122 // concept requirements
123 __glibcxx_function_requires(_InputIteratorConcept
<_InputIterator
>)
128 template<typename _BidirectionalIterator
, typename _Distance
>
130 __advance(_BidirectionalIterator
& __i
, _Distance __n
,
131 bidirectional_iterator_tag
)
133 // concept requirements
134 __glibcxx_function_requires(_BidirectionalIteratorConcept
<
135 _BidirectionalIterator
>)
144 template<typename _RandomAccessIterator
, typename _Distance
>
146 __advance(_RandomAccessIterator
& __i
, _Distance __n
,
147 random_access_iterator_tag
)
149 // concept requirements
150 __glibcxx_function_requires(_RandomAccessIteratorConcept
<
151 _RandomAccessIterator
>)
156 * @brief A generalization of pointer arithmetic.
157 * @param i An input iterator.
158 * @param n The @a delta by which to change @p i.
161 * This increments @p i by @p n. For bidirectional and random access
162 * iterators, @p n may be negative, in which case @p i is decremented.
164 * For random access iterators, this uses their @c + and @c - operations
165 * and are constant time. For other %iterator classes they are linear time.
167 template<typename _InputIterator
, typename _Distance
>
169 advance(_InputIterator
& __i
, _Distance __n
)
171 // concept requirements -- taken care of in __advance
172 typename iterator_traits
<_InputIterator
>::difference_type __d
= __n
;
173 std::__advance(__i
, __d
, std::__iterator_category(__i
));
176 #ifdef __GXX_EXPERIMENTAL_CXX0X__
178 template<typename _ForwardIterator
>
179 inline _ForwardIterator
180 next(_ForwardIterator __x
, typename
181 iterator_traits
<_ForwardIterator
>::difference_type __n
= 1)
183 std::advance(__x
, __n
);
187 template<typename _BidirectionalIterator
>
188 inline _BidirectionalIterator
189 prev(_BidirectionalIterator __x
, typename
190 iterator_traits
<_BidirectionalIterator
>::difference_type __n
= 1)
192 std::advance(__x
, -__n
);
196 #endif // __GXX_EXPERIMENTAL_CXX0X__
198 _GLIBCXX_END_NAMESPACE
200 #endif /* _STL_ITERATOR_BASE_FUNCS_H */