// Functions used by iterators -*- C++ -*- // Copyright (C) 2001, 2002, 2003, 2004 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 2, 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. // You should have received a copy of the GNU General Public License along // with this library; see the file COPYING. If not, write to the Free // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307, // USA. // As a special exception, you may use this file as part of a free software // library without restriction. Specifically, if other files instantiate // templates or use macros or inline functions from this file, or you compile // this file and link it with other files to produce an executable, this // file does not by itself cause the resulting executable to be covered by // the GNU General Public License. This exception does not however // invalidate any other reasons why the executable file might be covered by // the GNU General Public License. /* * * Copyright (c) 1994 * Hewlett-Packard Company * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Hewlett-Packard Company makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. * * * Copyright (c) 1996-1998 * Silicon Graphics Computer Systems, Inc. * * Permission to use, copy, modify, distribute and sell this software * and its documentation for any purpose is hereby granted without fee, * provided that the above copyright notice appear in all copies and * that both that copyright notice and this permission notice appear * in supporting documentation. Silicon Graphics makes no * representations about the suitability of this software for any * purpose. It is provided "as is" without express or implied warranty. */ /** @file stl_iterator_base_funcs.h * This is an internal header file, included by other library headers. * You should not attempt to use it directly. * * This file contains all of the general iterator-related utility * functions, such as distance() and advance(). */ #ifndef _ITERATOR_BASE_FUNCS_H #define _ITERATOR_BASE_FUNCS_H 1 #pragma GCC system_header #include <bits/concept_check.h> namespace std { template<typename _InputIterator> inline typename iterator_traits<_InputIterator>::difference_type __distance(_InputIterator __first, _InputIterator __last, input_iterator_tag) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) typename iterator_traits<_InputIterator>::difference_type __n = 0; while (__first != __last) { ++__first; ++__n; } return __n; } template<typename _RandomAccessIterator> inline typename iterator_traits<_RandomAccessIterator>::difference_type __distance(_RandomAccessIterator __first, _RandomAccessIterator __last, random_access_iterator_tag) { // concept requirements __glibcxx_function_requires(_RandomAccessIteratorConcept< _RandomAccessIterator>) return __last - __first; } /** * @brief A generalization of pointer arithmetic. * @param first An input iterator. * @param last An input iterator. * @return The distance between them. * * Returns @c n such that first + n == last. This requires that @p last * must be reachable from @p first. Note that @c n may be negative. * * For random access iterators, this uses their @c + and @c - operations * and are constant time. For other %iterator classes they are linear time. */ template<typename _InputIterator> inline typename iterator_traits<_InputIterator>::difference_type distance(_InputIterator __first, _InputIterator __last) { // concept requirements -- taken care of in __distance return std::__distance(__first, __last, std::__iterator_category(__first)); } template<typename _InputIterator, typename _Distance> inline void __advance(_InputIterator& __i, _Distance __n, input_iterator_tag) { // concept requirements __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>) while (__n--) ++__i; } template<typename _BidirectionalIterator, typename _Distance> inline void __advance(_BidirectionalIterator& __i, _Distance __n, bidirectional_iterator_tag) { // concept requirements __glibcxx_function_requires(_BidirectionalIteratorConcept< _BidirectionalIterator>) if (__n > 0) while (__n--) ++__i; else while (__n++) --__i; } template<typename _RandomAccessIterator, typename _Distance> inline void __advance(_RandomAccessIterator& __i, _Distance __n, random_access_iterator_tag) { // concept requirements __glibcxx_function_requires(_RandomAccessIteratorConcept< _RandomAccessIterator>) __i += __n; } /** * @brief A generalization of pointer arithmetic. * @param i An input iterator. * @param n The "delta" by which to change @p i. * @return Nothing. * * This increments @p i by @p n. For bidirectional and random access * iterators, @p n may be negative, in which case @p i is decremented. * * For random access iterators, this uses their @c + and @c - operations * and are constant time. For other %iterator classes they are linear time. */ template<typename _InputIterator, typename _Distance> inline void advance(_InputIterator& __i, _Distance __n) { // concept requirements -- taken care of in __advance std::__advance(__i, __n, std::__iterator_category(__i)); } } // namespace std #endif /* _ITERATOR_BASE_FUNCS_H */