--- /dev/null
+// (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
+// Use, modification, and distribution is subject to the Boost Software
+// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+// See library home page at http://www.boost.org/libs/numeric/conversion
+//
+// Contact the author at: fernando_cacciola@hotmail.com
+//
+#ifndef BOOST_NUMERIC_CONVERSION_DETAIL_CONVERTER_FLC_12NOV2002_HPP
+#define BOOST_NUMERIC_CONVERSION_DETAIL_CONVERTER_FLC_12NOV2002_HPP
+
+#include <functional>
+
+#include "boost/numeric/conversion/detail/meta.hpp"
+#include "boost/numeric/conversion/detail/conversion_traits.hpp"
+#include "boost/numeric/conversion/bounds.hpp"
+
+#include "boost/type_traits/is_same.hpp"
+
+#include "boost/mpl/integral_c.hpp"
+
+namespace boost { namespace numeric { namespace convdetail
+{
+ // Integral Constants representing rounding modes
+ typedef mpl::integral_c<std::float_round_style, std::round_toward_zero> round2zero_c ;
+ typedef mpl::integral_c<std::float_round_style, std::round_to_nearest> round2nearest_c ;
+ typedef mpl::integral_c<std::float_round_style, std::round_toward_infinity> round2inf_c ;
+ typedef mpl::integral_c<std::float_round_style, std::round_toward_neg_infinity> round2neg_inf_c ;
+
+ // Metafunction:
+ //
+ // for_round_style<RoundStyle,RoundToZero,RoundToNearest,RoundToInf,RoundToNegInf>::type
+ //
+ // {RoundStyle} Integral Constant specifying a round style as declared above.
+ // {RoundToZero,RoundToNearest,RoundToInf,RoundToNegInf} arbitrary types.
+ //
+ // Selects one of the 4 types according to the value of RoundStyle.
+ //
+ template<class RoundStyle,class RoundToZero,class RoundToNearest,class RoundToInf,class RoundToNegInf>
+ struct for_round_style
+ {
+ typedef ct_switch4<RoundStyle
+ , round2zero_c, round2nearest_c, round2inf_c // round2neg_inf_c
+ , RoundToZero , RoundToNearest , RoundToInf , RoundToNegInf
+ > selector ;
+
+ typedef typename selector::type type ;
+ } ;
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+//--------------------------------------------------------------------------
+// Range Checking Logic.
+//
+// The range checking logic is built up by combining 1 or 2 predicates.
+// Each predicate is encapsulated in a template class and exposes
+// the static member function 'apply'.
+//
+//--------------------------------------------------------------------------
+
+
+ // Because a particular logic can combine either 1 or two predicates, the following
+ // tags are used to allow the predicate applier to receive 2 preds, but optimize away
+ // one of them if it is 'non-applicable'
+ struct non_applicable { typedef mpl::false_ do_apply ; } ;
+ struct applicable { typedef mpl::true_ do_apply ; } ;
+
+
+ //--------------------------------------------------------------------------
+ //
+ // Range Checking Logic implementations.
+ //
+ // The following classes, collectivelly named 'Predicates', are instantiated within
+ // the corresponding range checkers.
+ // Their static member function 'apply' is called to perform the actual range checking logic.
+ //--------------------------------------------------------------------------
+
+ // s < Lowest(T) ? cNegOverflow : cInRange
+ //
+ template<class Traits>
+ struct LT_LoT : applicable
+ {
+ typedef typename Traits::target_type T ;
+ typedef typename Traits::source_type S ;
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result apply ( argument_type s )
+ {
+ return s < static_cast<S>(bounds<T>::lowest()) ? cNegOverflow : cInRange ;
+ }
+ } ;
+
+ // s < 0 ? cNegOverflow : cInRange
+ //
+ template<class Traits>
+ struct LT_Zero : applicable
+ {
+ typedef typename Traits::source_type S ;
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result apply ( argument_type s )
+ {
+ return s < static_cast<S>(0) ? cNegOverflow : cInRange ;
+ }
+ } ;
+
+ // s <= Lowest(T)-1 ? cNegOverflow : cInRange
+ //
+ template<class Traits>
+ struct LE_PrevLoT : applicable
+ {
+ typedef typename Traits::target_type T ;
+ typedef typename Traits::source_type S ;
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result apply ( argument_type s )
+ {
+ return s <= static_cast<S>(bounds<T>::lowest()) - static_cast<S>(1.0)
+ ? cNegOverflow : cInRange ;
+ }
+ } ;
+
+ // s < Lowest(T)-0.5 ? cNegOverflow : cInRange
+ //
+ template<class Traits>
+ struct LT_HalfPrevLoT : applicable
+ {
+ typedef typename Traits::target_type T ;
+ typedef typename Traits::source_type S ;
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result apply ( argument_type s )
+ {
+ return s < static_cast<S>(bounds<T>::lowest()) - static_cast<S>(0.5)
+ ? cNegOverflow : cInRange ;
+ }
+ } ;
+
+ // s > Highest(T) ? cPosOverflow : cInRange
+ //
+ template<class Traits>
+ struct GT_HiT : applicable
+ {
+ typedef typename Traits::target_type T ;
+ typedef typename Traits::source_type S ;
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result apply ( argument_type s )
+ {
+ return s > static_cast<S>(bounds<T>::highest())
+ ? cPosOverflow : cInRange ;
+ }
+ } ;
+
+ // s >= Lowest(T) + 1 ? cPosOverflow : cInRange
+ //
+ template<class Traits>
+ struct GE_SuccHiT : applicable
+ {
+ typedef typename Traits::target_type T ;
+ typedef typename Traits::source_type S ;
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result apply ( argument_type s )
+ {
+ return s >= static_cast<S>(bounds<T>::highest()) + static_cast<S>(1.0)
+ ? cPosOverflow : cInRange ;
+ }
+ } ;
+
+ // s >= Lowest(T) + 0.5 ? cPosgOverflow : cInRange
+ //
+ template<class Traits>
+ struct GT_HalfSuccHiT : applicable
+ {
+ typedef typename Traits::target_type T ;
+ typedef typename Traits::source_type S ;
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result apply ( argument_type s )
+ {
+ return s >= static_cast<S>(bounds<T>::highest()) + static_cast<S>(0.5)
+ ? cPosOverflow : cInRange ;
+ }
+ } ;
+
+
+ //--------------------------------------------------------------------------
+ //
+ // Predicate Combiner.
+ //
+ // This helper classes are used to possibly combine the range checking logic
+ // individually performed by the predicates
+ //
+ //--------------------------------------------------------------------------
+
+
+ // Applies both predicates: first 'PredA', and if it equals 'cInRange', 'PredB'
+ template<class PredA, class PredB>
+ struct applyBoth
+ {
+ typedef typename PredA::argument_type argument_type ;
+
+ static range_check_result apply ( argument_type s )
+ {
+ range_check_result r = PredA::apply(s) ;
+ if ( r == cInRange )
+ r = PredB::apply(s);
+ return r ;
+ }
+ } ;
+
+ template<class PredA, class PredB>
+ struct combine
+ {
+ typedef applyBoth<PredA,PredB> Both ;
+ typedef void NNone ; // 'None' is defined as a macro in (/usr/X11R6/include/X11/X.h)
+
+ typedef typename PredA::do_apply do_applyA ;
+ typedef typename PredB::do_apply do_applyB ;
+
+ typedef typename for_both<do_applyA, do_applyB, Both, PredA, PredB, NNone>::type type ;
+ } ;
+
+
+
+
+
+
+
+
+
+
+
+
+//--------------------------------------------------------------------------
+// Range Checker classes.
+//
+// The following classes are VISIBLE base classes of the user-level converter<> class.
+// They supply the optimized 'out_of_range()' and 'validate_range()' static member functions
+// visible in the user interface.
+//
+//--------------------------------------------------------------------------
+
+ // Dummy range checker.
+ template<class Traits>
+ struct dummy_range_checker
+ {
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result out_of_range ( argument_type ) { return cInRange ; }
+ static void validate_range ( argument_type ) {}
+ } ;
+
+ // Generic range checker.
+ //
+ // All the range checking logic for all possible combinations of source and target
+ // can be arranged in terms of one or two predicates, which test overflow on both neg/pos 'sides'
+ // of the ranges.
+ //
+ // These predicates are given here as IsNegOverflow and IsPosOverflow.
+ //
+ template<class Traits, class IsNegOverflow, class IsPosOverflow, class OverflowHandler>
+ struct generic_range_checker
+ {
+ typedef OverflowHandler overflow_handler ;
+
+ typedef typename Traits::argument_type argument_type ;
+
+ static range_check_result out_of_range ( argument_type s )
+ {
+ typedef typename combine<IsNegOverflow,IsPosOverflow>::type Predicate ;
+
+ return Predicate::apply(s);
+ }
+
+ static void validate_range ( argument_type s )
+ { OverflowHandler()( out_of_range(s) ) ; }
+ } ;
+
+
+
+//--------------------------------------------------------------------------
+//
+// Selectors for the optimized Range Checker class.
+//
+//--------------------------------------------------------------------------
+
+ 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
+
+
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