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1 | /*! |
2 | @file | |
3 | Adapts `std::ratio` for use with Hana. | |
4 | ||
5 | @copyright Louis Dionne 2013-2016 | |
6 | Distributed under the Boost Software License, Version 1.0. | |
7 | (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt) | |
8 | */ | |
9 | ||
10 | #ifndef BOOST_HANA_EXT_STD_RATIO_HPP | |
11 | #define BOOST_HANA_EXT_STD_RATIO_HPP | |
12 | ||
13 | #include <boost/hana/bool.hpp> | |
14 | #include <boost/hana/concept/integral_constant.hpp> | |
15 | #include <boost/hana/config.hpp> | |
16 | #include <boost/hana/core/when.hpp> | |
17 | #include <boost/hana/fwd/core/to.hpp> | |
18 | #include <boost/hana/fwd/core/tag_of.hpp> | |
19 | #include <boost/hana/fwd/div.hpp> | |
20 | #include <boost/hana/fwd/equal.hpp> | |
21 | #include <boost/hana/fwd/less.hpp> | |
22 | #include <boost/hana/fwd/minus.hpp> | |
23 | #include <boost/hana/fwd/mod.hpp> | |
24 | #include <boost/hana/fwd/mult.hpp> | |
25 | #include <boost/hana/fwd/one.hpp> | |
26 | #include <boost/hana/fwd/plus.hpp> | |
27 | #include <boost/hana/fwd/zero.hpp> | |
28 | ||
29 | #include <cstdint> | |
30 | #include <ratio> | |
31 | #include <type_traits> | |
32 | ||
33 | ||
34 | #ifdef BOOST_HANA_DOXYGEN_INVOKED | |
35 | namespace std { | |
36 | //! @ingroup group-ext-std | |
37 | //! Adaptation of `std::ratio` for Hana. | |
38 | //! | |
39 | //! | |
40 | //! Modeled concepts | |
41 | //! ---------------- | |
42 | //! 1. `Comparable`\n | |
43 | //! `std::ratio`s are compared for equality using `std::ratio_equal`. | |
44 | //! @include example/ext/std/ratio/comparable.cpp | |
45 | //! | |
46 | //! 2. `Orderable`\n | |
47 | //! `std::ratio`s are ordered using `std::ratio_less`. | |
48 | //! @include example/ext/std/ratio/orderable.cpp | |
49 | //! | |
50 | //! 3. `Monoid`, `Group`, `Ring`, and `EuclideanRing`\n | |
51 | //! `std::ratio`s are added, subtracted, multiplied and divided using | |
52 | //! `std::ratio_add`, `std::ratio_subtract`, `std::ratio_multiply` and | |
53 | //! `std::ratio_divide`, respectively. Furthermore, the neutral element | |
54 | //! for the additive operation is `std::ratio<0, 1>{}`, and the neutral | |
55 | //! element for the multiplicative operation is `std::ratio<1, 1>{}`. | |
56 | //! @include example/ext/std/ratio/arithmetic.cpp | |
57 | template <std::intmax_t Num, std::intmax_t Denom> | |
58 | class ratio { }; | |
59 | } | |
60 | #endif | |
61 | ||
62 | ||
63 | BOOST_HANA_NAMESPACE_BEGIN | |
64 | namespace ext { namespace std { struct ratio_tag; }} | |
65 | ||
66 | template <std::intmax_t num, std::intmax_t den> | |
67 | struct tag_of<std::ratio<num, den>> { | |
68 | using type = ext::std::ratio_tag; | |
69 | }; | |
70 | ||
71 | ////////////////////////////////////////////////////////////////////////// | |
72 | // Conversion from IntegralConstants | |
73 | ////////////////////////////////////////////////////////////////////////// | |
74 | template <typename C> | |
75 | struct to_impl<ext::std::ratio_tag, C, when< | |
76 | hana::IntegralConstant<C>::value | |
77 | >> { | |
78 | template <typename N> | |
79 | static constexpr auto apply(N const&) { | |
80 | return std::ratio<N::value>{}; | |
81 | } | |
82 | }; | |
83 | ||
84 | ////////////////////////////////////////////////////////////////////////// | |
85 | // Comparable | |
86 | ////////////////////////////////////////////////////////////////////////// | |
87 | template <> | |
88 | struct equal_impl<ext::std::ratio_tag, ext::std::ratio_tag> { | |
89 | template <typename R1, typename R2> | |
90 | static constexpr auto apply(R1 const&, R2 const&) | |
91 | { return hana::bool_c<std::ratio_equal<R1, R2>::value>; } | |
92 | }; | |
93 | ||
94 | ////////////////////////////////////////////////////////////////////////// | |
95 | // Orderable | |
96 | ////////////////////////////////////////////////////////////////////////// | |
97 | template <> | |
98 | struct less_impl<ext::std::ratio_tag, ext::std::ratio_tag> { | |
99 | template <typename R1, typename R2> | |
100 | static constexpr auto apply(R1 const&, R2 const&) | |
101 | { return hana::bool_c<std::ratio_less<R1, R2>::value>; } | |
102 | }; | |
103 | ||
104 | ////////////////////////////////////////////////////////////////////////// | |
105 | // Monoid | |
106 | ////////////////////////////////////////////////////////////////////////// | |
107 | template <> | |
108 | struct plus_impl<ext::std::ratio_tag, ext::std::ratio_tag> { | |
109 | template <typename R1, typename R2> | |
110 | static constexpr std::ratio_add<R1, R2> apply(R1 const&, R2 const&) | |
111 | { return {}; } | |
112 | }; | |
113 | ||
114 | template <> | |
115 | struct zero_impl<ext::std::ratio_tag> { | |
116 | static constexpr std::ratio<0> apply() | |
117 | { return {}; } | |
118 | }; | |
119 | ||
120 | ////////////////////////////////////////////////////////////////////////// | |
121 | // Group | |
122 | ////////////////////////////////////////////////////////////////////////// | |
123 | template <> | |
124 | struct minus_impl<ext::std::ratio_tag, ext::std::ratio_tag> { | |
125 | template <typename R1, typename R2> | |
126 | static constexpr std::ratio_subtract<R1, R2> apply(R1 const&, R2 const&) | |
127 | { return {}; } | |
128 | }; | |
129 | ||
130 | ////////////////////////////////////////////////////////////////////////// | |
131 | // Ring | |
132 | ////////////////////////////////////////////////////////////////////////// | |
133 | template <> | |
134 | struct mult_impl<ext::std::ratio_tag, ext::std::ratio_tag> { | |
135 | template <typename R1, typename R2> | |
136 | static constexpr std::ratio_multiply<R1, R2> apply(R1 const&, R2 const&) | |
137 | { return {}; } | |
138 | }; | |
139 | ||
140 | template <> | |
141 | struct one_impl<ext::std::ratio_tag> { | |
142 | static constexpr std::ratio<1> apply() | |
143 | { return {}; } | |
144 | }; | |
145 | ||
146 | ////////////////////////////////////////////////////////////////////////// | |
147 | // EuclideanRing | |
148 | ////////////////////////////////////////////////////////////////////////// | |
149 | template <> | |
150 | struct div_impl<ext::std::ratio_tag, ext::std::ratio_tag> { | |
151 | template <typename R1, typename R2> | |
152 | static constexpr std::ratio_divide<R1, R2> apply(R1 const&, R2 const&) | |
153 | { return {}; } | |
154 | }; | |
155 | ||
156 | template <> | |
157 | struct mod_impl<ext::std::ratio_tag, ext::std::ratio_tag> { | |
158 | template <typename R1, typename R2> | |
159 | static constexpr std::ratio<0> apply(R1 const&, R2 const&) | |
160 | { return {}; } | |
161 | }; | |
162 | BOOST_HANA_NAMESPACE_END | |
163 | ||
164 | #endif // !BOOST_HANA_EXT_STD_RATIO_HPP |