equal
deleted
inserted
replaced
|
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 |
|
17 namespace 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 |
|
29 template <class T> |
|
30 inline T next(T x) { return ++x; } |
|
31 |
|
32 template <class T, class Distance> |
|
33 inline T next(T x, Distance n) |
|
34 { |
|
35 std::advance(x, n); |
|
36 return x; |
|
37 } |
|
38 |
|
39 template <class T> |
|
40 inline T prior(T x) { return --x; } |
|
41 |
|
42 template <class T, class Distance> |
|
43 inline 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 |