comparison DEPENDENCIES/generic/include/boost/numeric/conversion/detail/converter.hpp @ 16:2665513ce2d3

Add boost headers

+//  (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: [e-mail]
+//
+#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
+
+