1 #ifndef BOOST_MP11_DETAIL_MP_COUNT_HPP_INCLUDED
2 #define BOOST_MP11_DETAIL_MP_COUNT_HPP_INCLUDED
3
4 // Copyright 2015, 2016 Peter Dimov.
5 //
6 // Distributed under the Boost Software License, Version 1.0.
7 //
8 // See accompanying file LICENSE_1_0.txt or copy at
9 // http://www.boost.org/LICENSE_1_0.txt
10
11 #include <boost/mp11/integral.hpp>
12 #include <boost/mp11/detail/mp_plus.hpp>
13 #include <boost/mp11/detail/config.hpp>
14
15 namespace boost
16 {
17 namespace mp11
18 {
19
20 // mp_count<L, V>
21 namespace detail
22 {
23
24 template<class L, class V> struct mp_count_impl;
25
26 #if defined( BOOST_MP11_HAS_FOLD_EXPRESSIONS )
27
28 template<template<class...> class L, class... T, class V> struct mp_count_impl<L<T...>, V>
29 {
30 using type = mp_size_t<(std::is_same<T, V>::value + ... + 0)>;
31 };
32
33 #elif !defined( BOOST_MP11_NO_CONSTEXPR )
34
cx_plus()35 constexpr std::size_t cx_plus()
36 {
37 return 0;
38 }
39
cx_plus(T1 t1,T...t)40 template<class T1, class... T> constexpr std::size_t cx_plus(T1 t1, T... t)
41 {
42 return static_cast<std::size_t>(t1) + cx_plus(t...);
43 }
44
45 template<class T1, class T2, class T3, class T4, class T5, class T6, class T7, class T8, class T9, class T10, class... T>
cx_plus(T1 t1,T2 t2,T3 t3,T4 t4,T5 t5,T6 t6,T7 t7,T8 t8,T9 t9,T10 t10,T...t)46 constexpr std::size_t cx_plus(T1 t1, T2 t2, T3 t3, T4 t4, T5 t5, T6 t6, T7 t7, T8 t8, T9 t9, T10 t10, T... t)
47 {
48 return static_cast<std::size_t>(t1 + t2 + t3 + t4 + t5 + t6 + t7 + t8 + t9 + t10) + cx_plus(t...);
49 }
50
51 template<template<class...> class L, class... T, class V> struct mp_count_impl<L<T...>, V>
52 {
53 using type = mp_size_t<cx_plus(std::is_same<T, V>::value...)>;
54 };
55
56 #else
57
58 template<template<class...> class L, class... T, class V> struct mp_count_impl<L<T...>, V>
59 {
60 using type = mp_size_t<mp_plus<std::is_same<T, V>...>::value>;
61 };
62
63 #endif
64
65 } // namespace detail
66
67 template<class L, class V> using mp_count = typename detail::mp_count_impl<L, V>::type;
68
69 // mp_count_if<L, P>
70 namespace detail
71 {
72
73 template<class L, template<class...> class P> struct mp_count_if_impl;
74
75 #if defined( BOOST_MP11_HAS_FOLD_EXPRESSIONS ) && !BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1920 )
76
77 template<template<class...> class L, class... T, template<class...> class P> struct mp_count_if_impl<L<T...>, P>
78 {
79 using type = mp_size_t<(mp_to_bool<P<T>>::value + ... + 0)>;
80 };
81
82 #elif !defined( BOOST_MP11_NO_CONSTEXPR )
83
84 template<template<class...> class L, class... T, template<class...> class P> struct mp_count_if_impl<L<T...>, P>
85 {
86 using type = mp_size_t<cx_plus(mp_to_bool<P<T>>::value...)>;
87 };
88
89 #else
90
91 template<template<class...> class L, class... T, template<class...> class P> struct mp_count_if_impl<L<T...>, P>
92 {
93 #if BOOST_MP11_WORKAROUND( BOOST_MP11_MSVC, < 1920 )
94
95 template<class T> struct _f { using type = mp_to_bool<P<T>>; };
96 using type = mp_size_t<mp_plus<typename _f<T>::type...>::value>;
97
98 #else
99
100 using type = mp_size_t<mp_plus<mp_to_bool<P<T>>...>::value>;
101
102 #endif
103 };
104
105 #endif
106
107 } // namespace detail
108
109 template<class L, template<class...> class P> using mp_count_if = typename detail::mp_count_if_impl<L, P>::type;
110 template<class L, class Q> using mp_count_if_q = mp_count_if<L, Q::template fn>;
111
112 } // namespace mp11
113 } // namespace boost
114
115 #endif // #ifndef BOOST_MP11_DETAIL_MP_COUNT_HPP_INCLUDED
116