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52 lines
1.3 KiB
52 lines
1.3 KiB
15 years ago
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// Boost next_prior.hpp header file ---------------------------------------//
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// (C) Copyright Dave Abrahams and Daniel Walker 1999-2003. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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// See http://www.boost.org/libs/utility for documentation.
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// Revision History
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// 13 Dec 2003 Added next(x, n) and prior(x, n) (Daniel Walker)
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#ifndef BOOST_NEXT_PRIOR_HPP_INCLUDED
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#define BOOST_NEXT_PRIOR_HPP_INCLUDED
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#include <iterator>
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namespace boost {
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// Helper functions for classes like bidirectional iterators not supporting
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// operator+ and operator-
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//
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// Usage:
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// const std::list<T>::iterator p = get_some_iterator();
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// const std::list<T>::iterator prev = boost::prior(p);
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// const std::list<T>::iterator next = boost::next(prev, 2);
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// Contributed by Dave Abrahams
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template <class T>
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inline T next(T x) { return ++x; }
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template <class T, class Distance>
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inline T next(T x, Distance n)
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{
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std::advance(x, n);
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return x;
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}
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template <class T>
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inline T prior(T x) { return --x; }
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template <class T, class Distance>
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inline T prior(T x, Distance n)
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{
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std::advance(x, -n);
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return x;
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}
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} // namespace boost
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#endif // BOOST_NEXT_PRIOR_HPP_INCLUDED
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