view release on metacpan or  search on metacpan

include/boost/numeric/conversion/detail/old_numeric_cast.hpp  view on Meta::CPAN

      };
# endif
    } // namespace detail

// less_than_type_min -
  //    x_is_signed should be numeric_limits<X>::is_signed
  //    y_is_signed should be numeric_limits<Y>::is_signed
  //    y_min should be numeric_limits<Y>::min()
  //
  //    check(x, y_min) returns true iff x < y_min without invoking comparisons
  //    between signed and unsigned values.
  //
  //    "poor man's partial specialization" is in use here.
    template <bool x_is_signed, bool y_is_signed>
    struct less_than_type_min
    {
        template <class X, class Y>
        static bool check(X x, Y y_min)
            { return x < y_min; }
    };

    template <>
    struct less_than_type_min<false, true>
    {
        template <class X, class Y>
        static bool check(X, Y)
            { return false; }
    };

    template <>
    struct less_than_type_min<true, false>
    {
        template <class X, class Y>
        static bool check(X x, Y)
            { return x < 0; }
    };

  // greater_than_type_max -
  //    same_sign should be:
  //            numeric_limits<X>::is_signed == numeric_limits<Y>::is_signed
  //    y_max should be numeric_limits<Y>::max()
  //
  //    check(x, y_max) returns true iff x > y_max without invoking comparisons
  //    between signed and unsigned values.
  //
  //    "poor man's partial specialization" is in use here.
    template <bool same_sign, bool x_is_signed>
    struct greater_than_type_max;

    template<>
    struct greater_than_type_max<true, true>
    {
        template <class X, class Y>
        static inline bool check(X x, Y y_max)
            { return x > y_max; }
    };

    template <>
    struct greater_than_type_max<false, true>
    {
        // What does the standard say about this? I think it's right, and it
        // will work with every compiler I know of.
        template <class X, class Y>
        static inline bool check(X x, Y)
            { return x >= 0 && static_cast<X>(static_cast<Y>(x)) != x; }
    };

    template<>
    struct greater_than_type_max<true, false>
    {
        template <class X, class Y>
        static inline bool check(X x, Y y_max)
            { return x > y_max; }
    };

    template <>
    struct greater_than_type_max<false, false>
    {
        // What does the standard say about this? I think it's right, and it
        // will work with every compiler I know of.
        template <class X, class Y>
        static inline bool check(X x, Y)
            { return static_cast<X>(static_cast<Y>(x)) != x; }
    };

#else // use #pragma hacks if available

  namespace detail
  {
# if BOOST_MSVC
#  pragma warning(push)
#  pragma warning(disable : 4018)
#  pragma warning(disable : 4146)
#elif defined(__BORLANDC__)
#  pragma option push -w-8041
# endif

       // Move to namespace boost in utility.hpp?
       template <class T>
       struct fixed_numeric_limits : public std::numeric_limits<T>
       {
           static inline T min BOOST_PREVENT_MACRO_SUBSTITUTION ()
           {
               return std::numeric_limits<T>::is_signed && (std::numeric_limits<T>::min)() >= 0
                   ? T(-(std::numeric_limits<T>::max)()) : (std::numeric_limits<T>::min)();
           }
       };

# if BOOST_MSVC
#  pragma warning(pop)
#elif defined(__BORLANDC__)
#  pragma option pop
# endif
  } // namespace detail

#endif

    template<typename Target, typename Source>
    inline Target numeric_cast(Source arg)
    {
        // typedefs abbreviating respective trait classes
        typedef detail::fixed_numeric_limits<Source> arg_traits;
        typedef detail::fixed_numeric_limits<Target> result_traits;

#if defined(BOOST_STRICT_CONFIG) \
    || (!defined(__HP_aCC) || __HP_aCC > 33900) \
         && (!defined(BOOST_NO_LIMITS_COMPILE_TIME_CONSTANTS) \
             || defined(BOOST_SGI_CPP_LIMITS))
        // typedefs that act as compile time assertions
        // (to be replaced by boost compile time assertions
        // as and when they become available and are stable)
        typedef bool argument_must_be_numeric[arg_traits::is_specialized];
        typedef bool result_must_be_numeric[result_traits::is_specialized];

        const bool arg_is_signed = arg_traits::is_signed;
        const bool result_is_signed = result_traits::is_signed;
        const bool same_sign = arg_is_signed == result_is_signed;

        if (less_than_type_min<arg_is_signed, result_is_signed>::check(arg, (result_traits::min)())