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// Functions used by iterators -*- C++ -*-
// Copyright (C) 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
// 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
* 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 _STL_ITERATOR_BASE_FUNCS_H
#define _STL_ITERATOR_BASE_FUNCS_H 1
#pragma GCC system_header
#include <bits/concept_check.h>
_GLIBCXX_BEGIN_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
typename iterator_traits<_InputIterator>::difference_type __d = __n;
std::__advance(__i, __d, std::__iterator_category(__i));
}
#ifdef __GXX_EXPERIMENTAL_CXX0X__
template<typename _InputIterator>
inline _InputIterator
next(_InputIterator __x, typename
iterator_traits<_InputIterator>::difference_type __n = 1)
{
std::advance(__x, __n);
return __x;
}
template<typename _BidirectionalIterator>
inline _BidirectionalIterator
prev(_BidirectionalIterator __x, typename
iterator_traits<_BidirectionalIterator>::difference_type __n = 1)
{
std::advance(__x, -__n);
return __x;
}
#endif
_GLIBCXX_END_NAMESPACE
#endif /* _STL_ITERATOR_BASE_FUNCS_H */
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