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