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1 | /*-----------------------------------------------------------------------------+ |
2 | Copyright (c) 2010-2011: Joachim Faulhaber | |
3 | +------------------------------------------------------------------------------+ | |
4 | Distributed under the Boost Software License, Version 1.0. | |
5 | (See accompanying file LICENCE.txt or copy at | |
6 | http://www.boost.org/LICENSE_1_0.txt) | |
7 | +-----------------------------------------------------------------------------*/ | |
8 | #ifndef BOOST_ICL_TYPE_TRAITS_INFINITY_HPP_JOFA_100322 | |
9 | #define BOOST_ICL_TYPE_TRAITS_INFINITY_HPP_JOFA_100322 | |
10 | ||
11 | #include <string> | |
12 | #include <boost/static_assert.hpp> | |
13 | #include <boost/icl/type_traits/is_numeric.hpp> | |
14 | #include <boost/icl/type_traits/rep_type_of.hpp> | |
15 | #include <boost/icl/type_traits/size_type_of.hpp> | |
16 | #include <boost/mpl/and.hpp> | |
17 | #include <boost/mpl/if.hpp> | |
18 | ||
19 | namespace boost{ namespace icl | |
20 | { | |
21 | ||
22 | template<class Type> struct has_std_infinity | |
23 | { | |
24 | typedef has_std_infinity type; | |
25 | BOOST_STATIC_CONSTANT(bool, | |
26 | value = ( is_numeric<Type>::value | |
27 | && std::numeric_limits<Type>::has_infinity | |
28 | ) | |
29 | ); | |
30 | }; | |
31 | ||
32 | template<class Type> struct has_max_infinity | |
33 | { | |
34 | typedef has_max_infinity type; | |
35 | BOOST_STATIC_CONSTANT(bool, | |
36 | value = ( is_numeric<Type>::value | |
37 | && ! std::numeric_limits<Type>::has_infinity | |
38 | ) | |
39 | ); | |
40 | }; | |
41 | ||
42 | //------------------------------------------------------------------------------ | |
43 | template <class Type, bool has_std_inf=false, bool has_std_max=false> | |
44 | struct get_numeric_infinity; | |
45 | ||
46 | template <class Type, bool has_std_max> | |
47 | struct get_numeric_infinity<Type, true, has_std_max> | |
48 | { | |
49 | typedef get_numeric_infinity type; | |
50 | static Type value() | |
51 | { | |
52 | return (std::numeric_limits<Type>::infinity)(); | |
53 | } | |
54 | }; | |
55 | ||
56 | template <class Type> | |
57 | struct get_numeric_infinity<Type, false, true> | |
58 | { | |
59 | typedef get_numeric_infinity type; | |
60 | static Type value() | |
61 | { | |
62 | return (std::numeric_limits<Type>::max)(); | |
63 | } | |
64 | }; | |
65 | ||
66 | template <class Type> | |
67 | struct get_numeric_infinity<Type, false, false> | |
68 | { | |
69 | typedef get_numeric_infinity type; | |
70 | static Type value() | |
71 | { | |
72 | return Type(); | |
73 | } | |
74 | }; | |
75 | ||
76 | template <class Type> | |
77 | struct numeric_infinity | |
78 | { | |
79 | typedef numeric_infinity type; | |
80 | static Type value() | |
81 | { | |
82 | return get_numeric_infinity< Type | |
83 | , has_std_infinity<Type>::value | |
84 | , has_max_infinity<Type>::value >::value(); | |
85 | } | |
86 | }; | |
87 | ||
88 | ||
89 | //------------------------------------------------------------------------------ | |
90 | template<class Type, bool has_numeric_inf, bool has_repr_inf, bool has_size, bool has_diff> | |
91 | struct get_infinity; | |
92 | ||
93 | template<class Type, bool has_repr_inf, bool has_size, bool has_diff> | |
94 | struct get_infinity<Type, true, has_repr_inf, has_size, has_diff> | |
95 | { | |
96 | typedef get_infinity type; | |
97 | ||
98 | static Type value() | |
99 | { | |
100 | return numeric_infinity<Type>::value(); | |
101 | } | |
102 | }; | |
103 | ||
104 | template<class Type, bool has_size, bool has_diff> | |
105 | struct get_infinity<Type, false, true, has_size, has_diff> | |
106 | { | |
107 | typedef get_infinity type; | |
108 | ||
109 | static Type value() | |
110 | { | |
111 | return Type(numeric_infinity<typename Type::rep>::value()); | |
112 | } | |
113 | }; | |
114 | ||
115 | template<class Type, bool has_diff> | |
116 | struct get_infinity<Type, false, false, true, has_diff> | |
117 | { | |
118 | typedef get_infinity type; | |
119 | typedef typename Type::size_type size_type; | |
120 | ||
121 | static Type value() | |
122 | { | |
123 | return Type(numeric_infinity<size_type>::value()); | |
124 | } | |
125 | }; | |
126 | ||
127 | template<class Type> | |
128 | struct get_infinity<Type, false, false, false, true> | |
129 | { | |
130 | typedef get_infinity type; | |
131 | typedef typename Type::difference_type difference_type; | |
132 | ||
133 | static Type value() | |
134 | { | |
135 | return identity_element<difference_type>::value(); | |
136 | } | |
137 | }; | |
138 | ||
139 | template<class Type> | |
140 | struct get_infinity<Type, false, false, false, false> | |
141 | { | |
142 | typedef get_infinity type; | |
143 | ||
144 | static Type value() | |
145 | { | |
146 | return identity_element<Type>::value(); | |
147 | } | |
148 | }; | |
149 | ||
150 | template <class Type> struct infinity | |
151 | { | |
152 | typedef infinity type; | |
153 | ||
154 | static Type value() | |
155 | { | |
156 | return | |
157 | get_infinity< Type | |
158 | , is_numeric<Type>::value | |
159 | , has_rep_type<Type>::value | |
160 | , has_size_type<Type>::value | |
161 | , has_difference_type<Type>::value | |
162 | >::value(); | |
163 | } | |
164 | }; | |
165 | ||
166 | template <> | |
167 | struct infinity<std::string> | |
168 | { | |
169 | typedef infinity type; | |
170 | ||
171 | static std::string value() | |
172 | { | |
173 | return std::string(); | |
174 | } | |
175 | }; | |
176 | ||
177 | }} // namespace boost icl | |
178 | ||
179 | #endif | |
180 | ||
181 |