mp_count.hpp 3.1 KB

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