source: NonGTP/Boost/boost/next_prior.hpp @ 857

Revision 857, 1.3 KB checked in by igarcia, 19 years ago (diff)
Line 
1//  Boost next_prior.hpp header file  ---------------------------------------//
2
3//  (C) Copyright Dave Abrahams and Daniel Walker 1999-2003. Distributed under the Boost
4//  Software License, Version 1.0. (See accompanying file
5//  LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6
7//  See http://www.boost.org/libs/utility for documentation.
8
9//  Revision History
10//  13 Dec 2003  Added next(x, n) and prior(x, n) (Daniel Walker)
11
12#ifndef BOOST_NEXT_PRIOR_HPP_INCLUDED
13#define BOOST_NEXT_PRIOR_HPP_INCLUDED
14
15#include <iterator>
16
17namespace boost {
18
19//  Helper functions for classes like bidirectional iterators not supporting
20//  operator+ and operator-
21//
22//  Usage:
23//    const std::list<T>::iterator p = get_some_iterator();
24//    const std::list<T>::iterator prev = boost::prior(p);
25//    const std::list<T>::iterator next = boost::next(prev, 2);
26
27//  Contributed by Dave Abrahams
28
29template <class T>
30inline T next(T x) { return ++x; }
31
32template <class T, class Distance>
33inline T next(T x, Distance n)
34{
35    std::advance(x, n);
36    return x;
37}
38
39template <class T>
40inline T prior(T x) { return --x; }
41
42template <class T, class Distance>
43inline T prior(T x, Distance n)
44{
45    std::advance(x, -n);
46    return x;
47}
48
49} // namespace boost
50
51#endif  // BOOST_NEXT_PRIOR_HPP_INCLUDED
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