1// Copyright (C) 2003, Fernando Luis Cacciola Carballal.
2//
3// Use, modification, and distribution is subject to the Boost Software
4// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
5// http://www.boost.org/LICENSE_1_0.txt)
6//
7// See http://www.boost.org/libs/optional for documentation.
8//
9// You are welcome to contact the author at:
10// fernando_cacciola@hotmail.com
11//
12#ifndef BOOST_UTILITY_COMPARE_POINTEES_25AGO2003_HPP
13#define BOOST_UTILITY_COMPARE_POINTEES_25AGO2003_HPP
14
15#include<functional>
16
17namespace boost {
18
19// template<class OP> bool equal_pointees(OP const& x, OP const& y);
20// template<class OP> struct equal_pointees_t;
21//
22// Being OP a model of OptionalPointee (either a pointer or an optional):
23//
24// If both x and y have valid pointees, returns the result of (*x == *y)
25// If only one has a valid pointee, returns false.
26// If none have valid pointees, returns true.
27// No-throw
28template<class OptionalPointee>
29inline
30bool equal_pointees ( OptionalPointee const& x, OptionalPointee const& y )
31{
32 return (!x) != (!y) ? false : ( !x ? true : (*x) == (*y) ) ;
33}
34
35template<class OptionalPointee>
36struct equal_pointees_t
37{
38 typedef bool result_type;
39 typedef OptionalPointee first_argument_type;
40 typedef OptionalPointee second_argument_type;
41
42 bool operator() ( OptionalPointee const& x, OptionalPointee const& y ) const
43 { return equal_pointees(x,y) ; }
44} ;
45
46// template<class OP> bool less_pointees(OP const& x, OP const& y);
47// template<class OP> struct less_pointees_t;
48//
49// Being OP a model of OptionalPointee (either a pointer or an optional):
50//
51// If y has not a valid pointee, returns false.
52// ElseIf x has not a valid pointee, returns true.
53// ElseIf both x and y have valid pointees, returns the result of (*x < *y)
54// No-throw
55template<class OptionalPointee>
56inline
57bool less_pointees ( OptionalPointee const& x, OptionalPointee const& y )
58{
59 return !y ? false : ( !x ? true : (*x) < (*y) ) ;
60}
61
62template<class OptionalPointee>
63struct less_pointees_t
64{
65 typedef bool result_type;
66 typedef OptionalPointee first_argument_type;
67 typedef OptionalPointee second_argument_type;
68
69 bool operator() ( OptionalPointee const& x, OptionalPointee const& y ) const
70 { return less_pointees(x,y) ; }
71} ;
72
73} // namespace boost
74
75#endif
76
77