converter.hpp

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//--------------------------------------------------------------------------

  template<class Traits,class OverflowHandler>
  struct GetRC_Sig2Sig_or_Unsig2Unsig
  {
    typedef dummy_range_checker<Traits> Dummy ;

    typedef LT_LoT<Traits> Pred1 ;
    typedef GT_HiT<Traits> Pred2 ;

    typedef generic_range_checker<Traits,Pred1,Pred2,OverflowHandler> Normal ;

    typedef typename Traits::subranged subranged ;

    typedef typename mpl::if_<subranged,Normal,Dummy>::type type ;
  } ;

  template<class Traits, class OverflowHandler>
  struct GetRC_Sig2Unsig
  {
    typedef LT_Zero<Traits> Pred1 ;
    typedef GT_HiT <Traits> Pred2 ;

    typedef generic_range_checker<Traits,Pred1,Pred2,OverflowHandler> ChoiceA ;

    typedef generic_range_checker<Traits,Pred1,non_applicable,OverflowHandler> ChoiceB ;

    typedef typename Traits::target_type T ;
    typedef typename Traits::source_type S ;

    typedef typename subranged_Unsig2Sig<S,T>::type oposite_subranged ;

    typedef typename mpl::not_<oposite_subranged>::type positively_subranged ;

    typedef typename mpl::if_<positively_subranged,ChoiceA,ChoiceB>::type type ;
  } ;

  template<class Traits, class OverflowHandler>
  struct GetRC_Unsig2Sig
  {
    typedef GT_HiT<Traits> Pred1 ;

    typedef generic_range_checker<Traits,non_applicable,Pred1,OverflowHandler> type ;
  } ;

  template<class Traits,class OverflowHandler>
  struct GetRC_Int2Int
  {
    typedef GetRC_Sig2Sig_or_Unsig2Unsig<Traits,OverflowHandler> Sig2SigQ     ;
    typedef GetRC_Sig2Unsig             <Traits,OverflowHandler> Sig2UnsigQ   ;
    typedef GetRC_Unsig2Sig             <Traits,OverflowHandler> Unsig2SigQ   ;
    typedef Sig2SigQ                                             Unsig2UnsigQ ;

    typedef typename Traits::sign_mixture sign_mixture ;

    typedef typename
      for_sign_mixture<sign_mixture,Sig2SigQ,Sig2UnsigQ,Unsig2SigQ,Unsig2UnsigQ>::type
        selector ;

    typedef typename selector::type type ;
  } ;

  template<class Traits>
  struct GetRC_Int2Float
  {
    typedef dummy_range_checker<Traits> type ;
  } ;

  template<class Traits, class OverflowHandler, class Float2IntRounder>
  struct GetRC_Float2Int
  {
    typedef LE_PrevLoT    <Traits> Pred1 ;
    typedef GE_SuccHiT    <Traits> Pred2 ;
    typedef LT_HalfPrevLoT<Traits> Pred3 ;
    typedef GT_HalfSuccHiT<Traits> Pred4 ;
    typedef GT_HiT        <Traits> Pred5 ;
    typedef LT_LoT        <Traits> Pred6 ;

    typedef generic_range_checker<Traits,Pred1,Pred2,OverflowHandler> ToZero    ;
    typedef generic_range_checker<Traits,Pred3,Pred4,OverflowHandler> ToNearest ;
    typedef generic_range_checker<Traits,Pred1,Pred5,OverflowHandler> ToInf     ;
    typedef generic_range_checker<Traits,Pred6,Pred2,OverflowHandler> ToNegInf  ;

    typedef typename Float2IntRounder::round_style round_style ;

    typedef typename for_round_style<round_style,ToZero,ToNearest,ToInf,ToNegInf>::type type ;
  } ;

  template<class Traits, class OverflowHandler>
  struct GetRC_Float2Float
  {
    typedef dummy_range_checker<Traits> Dummy ;

    typedef LT_LoT<Traits> Pred1 ;
    typedef GT_HiT<Traits> Pred2 ;

    typedef generic_range_checker<Traits,Pred1,Pred2,OverflowHandler> Normal ;

    typedef typename Traits::subranged subranged ;

    typedef typename mpl::if_<subranged,Normal,Dummy>::type type ;
  } ;

  template<class Traits, class OverflowHandler, class Float2IntRounder>
  struct GetRC_BuiltIn2BuiltIn
  {
    typedef GetRC_Int2Int<Traits,OverflowHandler>                    Int2IntQ ;
    typedef GetRC_Int2Float<Traits>                                  Int2FloatQ ;
    typedef GetRC_Float2Int<Traits,OverflowHandler,Float2IntRounder> Float2IntQ ;
    typedef GetRC_Float2Float<Traits,OverflowHandler>                Float2FloatQ ;

    typedef typename Traits::int_float_mixture int_float_mixture ;

    typedef typename for_int_float_mixture<int_float_mixture, Int2IntQ, Int2FloatQ, Float2IntQ, Float2FloatQ>::type selector ;

    typedef typename selector::type type ;
  } ;

  template<class Traits, class OverflowHandler, class Float2IntRounder>
  struct GetRC
  {
    typedef GetRC_BuiltIn2BuiltIn<Traits,OverflowHandler,Float2IntRounder> BuiltIn2BuiltInQ ;

    typedef dummy_range_checker<Traits> Dummy ;

    typedef mpl::identity<Dummy> DummyQ ;

    typedef typename Traits::udt_builtin_mixture udt_builtin_mixture ;

    typedef typename for_udt_builtin_mixture<udt_builtin_mixture,BuiltIn2BuiltInQ,DummyQ,DummyQ,DummyQ>::type selector ;

    typedef typename selector::type type ;
  } ;




//--------------------------------------------------------------------------
//                             Converter classes.
//
// The following classes are VISIBLE base classes of the user-level converter<> class.
// They supply the optimized 'nearbyint()' and 'convert()' static member functions
// visible in the user interface.
//
//--------------------------------------------------------------------------

  //
  // Trivial Converter : used when (cv-unqualified) T == (cv-unqualified)  S
  //
  template<class Traits>
  struct trivial_converter_impl : public std::unary_function<  BOOST_DEDUCED_TYPENAME Traits::argument_type
                                                              ,BOOST_DEDUCED_TYPENAME Traits::result_type
                                                            >
                                 ,public dummy_range_checker<Traits>
  {
    typedef Traits traits ;

    typedef typename Traits::source_type   source_type   ;
    typedef typename Traits::argument_type argument_type ;
    typedef typename Traits::result_type   result_type   ;

    static result_type low_level_convert ( argument_type s ) { return s ; }
    static source_type nearbyint         ( argument_type s ) { return s ; }
    static result_type convert           ( argument_type s ) { return s ; }
  } ;


  //
  // Rounding Converter : used for float to integral conversions.
  //
  template<class Traits,class RangeChecker,class RawConverter,class Float2IntRounder>
  struct rounding_converter : public std::unary_function<  BOOST_DEDUCED_TYPENAME Traits::argument_type
                                                          ,BOOST_DEDUCED_TYPENAME Traits::result_type
                                                        >
                             ,public RangeChecker
                             ,public Float2IntRounder
                             ,public RawConverter
  {
    typedef RangeChecker     RangeCheckerBase ;
    typedef Float2IntRounder Float2IntRounderBase ;
    typedef RawConverter     RawConverterBase ;

    typedef Traits traits ;

    typedef typename Traits::source_type   source_type   ;
    typedef typename Traits::argument_type argument_type ;
    typedef typename Traits::result_type   result_type   ;

    static result_type convert ( argument_type s )
    {
      RangeCheckerBase::validate_range(s);
      source_type s1 = Float2IntRounderBase::nearbyint(s);
      return RawConverterBase::low_level_convert(s1);
    }
  } ;


  //
  // Non-Rounding Converter : used for all other conversions.
  //
  template<class Traits,class RangeChecker,class RawConverter>
  struct non_rounding_converter : public std::unary_function< BOOST_DEDUCED_TYPENAME Traits::argument_type
                                                             ,BOOST_DEDUCED_TYPENAME Traits::result_type
                                                           >
                                 ,public RangeChecker
                                 ,public RawConverter
  {
    typedef RangeChecker RangeCheckerBase ;
    typedef RawConverter RawConverterBase ;

    typedef Traits traits ;

    typedef typename Traits::source_type   source_type   ;
    typedef typename Traits::argument_type argument_type ;
    typedef typename Traits::result_type   result_type   ;

    static source_type nearbyint ( argument_type s ) { return s ; }

    static result_type convert ( argument_type s )
    {
      RangeCheckerBase::validate_range(s);
      return RawConverterBase::low_level_convert(s);
    }
  } ;




//--------------------------------------------------------------------------
//
// Selectors for the optimized Converter class.
//
//--------------------------------------------------------------------------

  template<class Traits,class OverflowHandler,class Float2IntRounder,class RawConverter, class UserRangeChecker>
  struct get_non_trivial_converter
  {
    typedef GetRC<Traits,OverflowHandler,Float2IntRounder> InternalRangeCheckerQ ;

    typedef is_same<UserRangeChecker,UseInternalRangeChecker> use_internal_RC ;

    typedef mpl::identity<UserRangeChecker> UserRangeCheckerQ ;

    typedef typename
      mpl::eval_if<use_internal_RC,InternalRangeCheckerQ,UserRangeCheckerQ>::type
        RangeChecker ;

    typedef non_rounding_converter<Traits,RangeChecker,RawConverter>              NonRounding ;
    typedef rounding_converter<Traits,RangeChecker,RawConverter,Float2IntRounder> Rounding ;

    typedef mpl::identity<NonRounding> NonRoundingQ ;
    typedef mpl::identity<Rounding>    RoundingQ    ;

    typedef typename Traits::int_float_mixture int_float_mixture ;

    typedef typename
      for_int_float_mixture<int_float_mixture, NonRoundingQ, NonRoundingQ, RoundingQ, NonRoundingQ>::type
        selector ;

    typedef typename selector::type type ;
  } ;

  template< class Traits
           ,class OverflowHandler
           ,class Float2IntRounder
           ,class RawConverter
           ,class UserRangeChecker
          >
  struct get_converter_impl
  {
#if BOOST_WORKAROUND(__BORLANDC__, BOOST_TESTED_AT( 0x0561 ) )
    // bcc55 prefers sometimes template parameters to be explicit local types.
    // (notice that is is illegal to reuse the names like this)
    typedef Traits           Traits ;
    typedef OverflowHandler  OverflowHandler ;
    typedef Float2IntRounder Float2IntRounder ;
    typedef RawConverter     RawConverter ;
    typedef UserRangeChecker UserRangeChecker ;
#endif

    typedef trivial_converter_impl<Traits> Trivial ;
    typedef mpl::identity        <Trivial> TrivialQ ;

    typedef get_non_trivial_converter< Traits
                                      ,OverflowHandler
                                      ,Float2IntRounder
                                      ,RawConverter
                                      ,UserRangeChecker
                                     > NonTrivialQ ;

    typedef typename Traits::trivial trivial ;

    typedef typename mpl::eval_if<trivial,TrivialQ,NonTrivialQ>::type type ;
  } ;

} } } // namespace boost::numeric::convdetail

#endif