lcm.hpp 3.7 KB

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  1. ////////////////////////////////////////////////////////////////////
  2. //
  3. // Copyright Vicente J. Botet Escriba 2010
  4. //
  5. // Distributed under the Boost Software License, Version 1.0.
  6. // (See accompanying file LICENSE_1_0.txt or copy at
  7. // http://www.boost.org/LICENSE_1_0.txt)
  8. //
  9. // See http://www.boost.org/libs/mpl for documentation.
  10. //
  11. ////////////////////////////////////////////////////////////////////
  12. #ifndef BOOST_MPL_LCM_HPP_INCLUDED
  13. #define BOOST_MPL_LCM_HPP_INCLUDED
  14. #include <boost/mpl/integral_c.hpp>
  15. #include <boost/ratio/detail/mpl/abs.hpp>
  16. #include <boost/mpl/aux_/largest_int.hpp>
  17. #include <boost/mpl/aux_/na_spec.hpp>
  18. #include <boost/mpl/aux_/lambda_support.hpp>
  19. #include <boost/mpl/aux_/config/integral.hpp>
  20. #include <boost/mpl/aux_/config/static_constant.hpp>
  21. #include <boost/mpl/aux_/config/dependent_nttp.hpp>
  22. #include <boost/cstdint.hpp>
  23. #if !defined(BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2) \
  24. && !defined(BOOST_MPL_PREPROCESSING_MODE) \
  25. && !defined(__CUDACC__) \
  26. && ( defined(BOOST_MSVC) \
  27. || BOOST_WORKAROUND(__EDG_VERSION__, <= 238) \
  28. )
  29. # define BOOST_MPL_CFG_NO_NESTED_VALUE_ARITHMETIC_2
  30. #endif
  31. namespace boost { namespace mpl {
  32. template< typename Tag1, typename Tag2 > struct lcm_impl;
  33. template< typename T > struct lcm_tag
  34. {
  35. typedef typename T::tag type;
  36. };
  37. template<
  38. typename BOOST_MPL_AUX_NA_PARAM(N1)
  39. , typename BOOST_MPL_AUX_NA_PARAM(N2)
  40. >
  41. struct lcm
  42. : lcm_impl<
  43. typename lcm_tag<N1>::type
  44. , typename lcm_tag<N2>::type
  45. >::template apply<N1, N2>::type
  46. {
  47. BOOST_MPL_AUX_LAMBDA_SUPPORT(2, lcm, (N1, N2))
  48. };
  49. BOOST_MPL_AUX_NA_SPEC(2, lcm)
  50. template<
  51. typename T
  52. , T n1
  53. , T n2
  54. >
  55. struct lcm_c
  56. : lcm<integral_c<T,n1>,integral_c<T,n2> >
  57. {
  58. };
  59. namespace aux {
  60. // Workaround for error: the type of partial specialization template parameter constant "n2"
  61. // depends on another template parameter
  62. // Note: this solution could be wrong for n1 or n2 = [2**63 .. 2**64-1]
  63. #if defined(BOOST_MPL_CFG_NO_DEPENDENT_NONTYPE_PARAMETER_IN_PARTIAL_SPEC)
  64. template< typename T1, boost::intmax_t n1, bool n1_is_0
  65. , typename T2, boost::intmax_t n2, bool n2_is_0 >
  66. struct lcm_aux
  67. : abs<integral_c< typename aux::largest_int<T1, T2>::type,
  68. ( n1 / gcd<integral_c<T1,n1>, integral_c<T2,n2> >::value * n2 )
  69. > >
  70. {};
  71. template <typename T1, boost::intmax_t n1, typename T2, boost::intmax_t n2>
  72. struct lcm_aux<T1, n1, false, T2, n2, true> : integral_c<T2, 0>
  73. {};
  74. template <typename T1, boost::intmax_t n1, typename T2, boost::intmax_t n2, bool C>
  75. struct lcm_aux<T1, n1, true, T2, n2, C> : integral_c<T1, 0>
  76. {};
  77. #else // defined(BOOST_MPL_CFG_NO_DEPENDENT_NONTYPE_PARAMETER_IN_PARTIAL_SPEC)
  78. template< typename T1, T1 n1, bool n1_is_0, typename T2, T2 n2, bool n2_is_0 >
  79. struct lcm_aux
  80. : abs<integral_c< typename aux::largest_int<T1, T2>::type,
  81. ( n1 / gcd<integral_c<T1,n1>, integral_c<T2,n2> >::value * n2 )
  82. > >
  83. {};
  84. template <typename T1, T1 n1, typename T2, T2 n2>
  85. struct lcm_aux<T1, n1, false, T2, n2, true> : integral_c<T2, 0>
  86. {};
  87. template <typename T1, T1 n1, typename T2, T2 n2, bool C>
  88. struct lcm_aux<T1, n1, true, T2, n2, C> : integral_c<T1, 0>
  89. {};
  90. #endif // defined(BOOST_MPL_CFG_NO_DEPENDENT_NONTYPE_PARAMETER_IN_PARTIAL_SPEC)
  91. }
  92. template<>
  93. struct lcm_impl<integral_c_tag, integral_c_tag>
  94. {
  95. template< typename N1, typename N2 > struct apply
  96. : abs<aux::lcm_aux< typename N1::value_type, N1::value, N1::value==0,
  97. typename N2::value_type, N2::value, N2::value==0 > >
  98. {
  99. };
  100. };
  101. }}
  102. #endif // BOOST_MPL_LCM_HPP_INCLUDED