Line data Source code
1 : // Functions used by iterators -*- C++ -*-
2 :
3 : // Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
4 : // Free Software Foundation, Inc.
5 : //
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)
10 : // any later version.
11 :
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.
16 :
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.
20 :
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/>.
25 :
26 : /*
27 : *
28 : * Copyright (c) 1994
29 : * Hewlett-Packard Company
30 : *
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.
38 : *
39 : *
40 : * Copyright (c) 1996-1998
41 : * Silicon Graphics Computer Systems, Inc.
42 : *
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.
50 : */
51 :
52 : /** @file stl_iterator_base_funcs.h
53 : * This is an internal header file, included by other library headers.
54 : * You should not attempt to use it directly.
55 : *
56 : * This file contains all of the general iterator-related utility
57 : * functions, such as distance() and advance().
58 : */
59 :
60 : #ifndef _STL_ITERATOR_BASE_FUNCS_H
61 : #define _STL_ITERATOR_BASE_FUNCS_H 1
62 :
63 : #pragma GCC system_header
64 : #include <bits/concept_check.h>
65 :
66 : _GLIBCXX_BEGIN_NAMESPACE(std)
67 :
68 : template<typename _InputIterator>
69 : inline typename iterator_traits<_InputIterator>::difference_type
70 99456 : __distance(_InputIterator __first, _InputIterator __last,
71 : input_iterator_tag)
72 : {
73 : // concept requirements
74 : __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
75 :
76 99456 : typename iterator_traits<_InputIterator>::difference_type __n = 0;
77 1027670 : while (__first != __last)
78 : {
79 828758 : ++__first;
80 828758 : ++__n;
81 : }
82 99456 : return __n;
83 : }
84 :
85 : template<typename _RandomAccessIterator>
86 : inline typename iterator_traits<_RandomAccessIterator>::difference_type
87 0 : __distance(_RandomAccessIterator __first, _RandomAccessIterator __last,
88 : random_access_iterator_tag)
89 : {
90 : // concept requirements
91 : __glibcxx_function_requires(_RandomAccessIteratorConcept<
92 : _RandomAccessIterator>)
93 0 : return __last - __first;
94 : }
95 :
96 : /**
97 : * @brief A generalization of pointer arithmetic.
98 : * @param first An input iterator.
99 : * @param last An input iterator.
100 : * @return The distance between them.
101 : *
102 : * Returns @c n such that first + n == last. This requires that @p last
103 : * must be reachable from @p first. Note that @c n may be negative.
104 : *
105 : * For random access iterators, this uses their @c + and @c - operations
106 : * and are constant time. For other %iterator classes they are linear time.
107 : */
108 : template<typename _InputIterator>
109 : inline typename iterator_traits<_InputIterator>::difference_type
110 99456 : distance(_InputIterator __first, _InputIterator __last)
111 : {
112 : // concept requirements -- taken care of in __distance
113 : return std::__distance(__first, __last,
114 99456 : std::__iterator_category(__first));
115 : }
116 :
117 : template<typename _InputIterator, typename _Distance>
118 : inline void
119 : __advance(_InputIterator& __i, _Distance __n, input_iterator_tag)
120 : {
121 : // concept requirements
122 : __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
123 : while (__n--)
124 : ++__i;
125 : }
126 :
127 : template<typename _BidirectionalIterator, typename _Distance>
128 : inline void
129 0 : __advance(_BidirectionalIterator& __i, _Distance __n,
130 : bidirectional_iterator_tag)
131 : {
132 : // concept requirements
133 : __glibcxx_function_requires(_BidirectionalIteratorConcept<
134 : _BidirectionalIterator>)
135 0 : if (__n > 0)
136 0 : while (__n--)
137 0 : ++__i;
138 : else
139 0 : while (__n++)
140 0 : --__i;
141 0 : }
142 :
143 : template<typename _RandomAccessIterator, typename _Distance>
144 : inline void
145 : __advance(_RandomAccessIterator& __i, _Distance __n,
146 : random_access_iterator_tag)
147 : {
148 : // concept requirements
149 : __glibcxx_function_requires(_RandomAccessIteratorConcept<
150 : _RandomAccessIterator>)
151 : __i += __n;
152 : }
153 :
154 : /**
155 : * @brief A generalization of pointer arithmetic.
156 : * @param i An input iterator.
157 : * @param n The "delta" by which to change @p i.
158 : * @return Nothing.
159 : *
160 : * This increments @p i by @p n. For bidirectional and random access
161 : * iterators, @p n may be negative, in which case @p i is decremented.
162 : *
163 : * For random access iterators, this uses their @c + and @c - operations
164 : * and are constant time. For other %iterator classes they are linear time.
165 : */
166 : template<typename _InputIterator, typename _Distance>
167 : inline void
168 0 : advance(_InputIterator& __i, _Distance __n)
169 : {
170 : // concept requirements -- taken care of in __advance
171 0 : typename iterator_traits<_InputIterator>::difference_type __d = __n;
172 0 : std::__advance(__i, __d, std::__iterator_category(__i));
173 0 : }
174 :
175 : #ifdef __GXX_EXPERIMENTAL_CXX0X__
176 : template<typename _InputIterator>
177 : inline _InputIterator
178 : next(_InputIterator __x, typename
179 : iterator_traits<_InputIterator>::difference_type __n = 1)
180 : {
181 : std::advance(__x, __n);
182 : return __x;
183 : }
184 :
185 : template<typename _BidirectionalIterator>
186 : inline _BidirectionalIterator
187 : prev(_BidirectionalIterator __x, typename
188 : iterator_traits<_BidirectionalIterator>::difference_type __n = 1)
189 : {
190 : std::advance(__x, -__n);
191 : return __x;
192 : }
193 : #endif
194 :
195 : _GLIBCXX_END_NAMESPACE
196 :
197 : #endif /* _STL_ITERATOR_BASE_FUNCS_H */
|
