Chris@16: //  (c) Copyright Fernando Luis Cacciola Carballal 2000-2004
Chris@16: //  Use, modification, and distribution is subject to the Boost Software
Chris@16: //  License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16: //  http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  See library home page at http://www.boost.org/libs/numeric/conversion
Chris@16: //
Chris@16: // Contact the author at: fernando_cacciola@hotmail.com
Chris@16: //
Chris@16: #ifndef BOOST_NUMERIC_CONVERSION_CONVERTER_POLICIES_FLC_12NOV2002_HPP
Chris@16: #define BOOST_NUMERIC_CONVERSION_CONVERTER_POLICIES_FLC_12NOV2002_HPP
Chris@16: 
Chris@16: #include <typeinfo> // for std::bad_cast
Chris@16: 
Chris@16: #include <boost/config/no_tr1/cmath.hpp> // for std::floor and std::ceil
Chris@16: #include <boost/throw_exception.hpp>
Chris@16: 
Chris@16: #include <functional>
Chris@16: 
Chris@16: #include "boost/type_traits/is_arithmetic.hpp"
Chris@16: 
Chris@16: #include "boost/mpl/if.hpp"
Chris@16: #include "boost/mpl/integral_c.hpp"
Chris@16: 
Chris@16: namespace boost { namespace numeric
Chris@16: {
Chris@16: 
Chris@16: template<class S>
Chris@16: struct Trunc
Chris@16: {
Chris@16:   typedef S source_type ;
Chris@16: 
Chris@16:   typedef typename mpl::if_< is_arithmetic<S>,S,S const&>::type argument_type ;
Chris@16: 
Chris@16:   static source_type nearbyint ( argument_type s )
Chris@16:   {
Chris@16: #if !defined(BOOST_NO_STDC_NAMESPACE)
Chris@16:     using std::floor ;
Chris@16:     using std::ceil  ;
Chris@16: #endif
Chris@16: 
Chris@16:     return s < static_cast<S>(0) ? ceil(s) : floor(s) ;
Chris@16:   }
Chris@16: 
Chris@16:   typedef mpl::integral_c< std::float_round_style, std::round_toward_zero> round_style ;
Chris@16: } ;
Chris@16: 
Chris@16: 
Chris@16: 
Chris@16: template<class S>
Chris@16: struct Floor
Chris@16: {
Chris@16:   typedef S source_type ;
Chris@16: 
Chris@16:   typedef typename mpl::if_< is_arithmetic<S>,S,S const&>::type argument_type ;
Chris@16: 
Chris@16:   static source_type nearbyint ( argument_type s )
Chris@16:   {
Chris@16: #if !defined(BOOST_NO_STDC_NAMESPACE)
Chris@16:     using std::floor ;
Chris@16: #endif
Chris@16: 
Chris@16:     return floor(s) ;
Chris@16:   }
Chris@16: 
Chris@16:   typedef mpl::integral_c< std::float_round_style, std::round_toward_neg_infinity> round_style ;
Chris@16: } ;
Chris@16: 
Chris@16: template<class S>
Chris@16: struct Ceil
Chris@16: {
Chris@16:   typedef S source_type ;
Chris@16: 
Chris@16:   typedef typename mpl::if_< is_arithmetic<S>,S,S const&>::type argument_type ;
Chris@16: 
Chris@16:   static source_type nearbyint ( argument_type s )
Chris@16:   {
Chris@16: #if !defined(BOOST_NO_STDC_NAMESPACE)
Chris@16:     using std::ceil ;
Chris@16: #endif
Chris@16: 
Chris@16:     return ceil(s) ;
Chris@16:   }
Chris@16: 
Chris@16:   typedef mpl::integral_c< std::float_round_style, std::round_toward_infinity> round_style ;
Chris@16: } ;
Chris@16: 
Chris@16: template<class S>
Chris@16: struct RoundEven
Chris@16: {
Chris@16:   typedef S source_type ;
Chris@16: 
Chris@16:   typedef typename mpl::if_< is_arithmetic<S>,S,S const&>::type argument_type ;
Chris@16: 
Chris@16:   static source_type nearbyint ( argument_type s )
Chris@16:   {
Chris@16:     // Algorithm contributed by Guillaume Melquiond
Chris@16: 
Chris@16: #if !defined(BOOST_NO_STDC_NAMESPACE)
Chris@16:     using std::floor ;
Chris@16:     using std::ceil  ;
Chris@16: #endif
Chris@16: 
Chris@16:     // only works inside the range not at the boundaries
Chris@16:     S prev = floor(s);
Chris@16:     S next = ceil(s);
Chris@16: 
Chris@16:     S rt = (s - prev) - (next - s); // remainder type
Chris@16: 
Chris@16:     S const zero(0.0);
Chris@16:     S const two(2.0);
Chris@16: 
Chris@16:     if ( rt < zero )
Chris@16:       return prev;
Chris@16:     else if ( rt > zero )
Chris@16:       return next;
Chris@16:     else
Chris@16:     {
Chris@16:       bool is_prev_even = two * floor(prev / two) == prev ;
Chris@16:       return ( is_prev_even ? prev : next ) ;
Chris@16:     }
Chris@16:   }
Chris@16: 
Chris@16:   typedef mpl::integral_c< std::float_round_style, std::round_to_nearest> round_style ;
Chris@16: } ;
Chris@16: 
Chris@16: 
Chris@16: enum range_check_result
Chris@16: {
Chris@16:   cInRange     = 0 ,
Chris@16:   cNegOverflow = 1 ,
Chris@16:   cPosOverflow = 2
Chris@16: } ;
Chris@16: 
Chris@16: class bad_numeric_cast : public std::bad_cast
Chris@16: {
Chris@16:   public:
Chris@16: 
Chris@16:     virtual const char * what() const throw()
Chris@16:       {  return "bad numeric conversion: overflow"; }
Chris@16: };
Chris@16: 
Chris@16: class negative_overflow : public bad_numeric_cast
Chris@16: {
Chris@16:   public:
Chris@16: 
Chris@16:     virtual const char * what() const throw()
Chris@16:       {  return "bad numeric conversion: negative overflow"; }
Chris@16: };
Chris@16: class positive_overflow : public bad_numeric_cast
Chris@16: {
Chris@16:   public:
Chris@16: 
Chris@16:     virtual const char * what() const throw()
Chris@16:       { return "bad numeric conversion: positive overflow"; }
Chris@16: };
Chris@16: 
Chris@16: struct def_overflow_handler
Chris@16: {
Chris@16:   void operator() ( range_check_result r ) // throw(negative_overflow,positive_overflow)
Chris@16:   {
Chris@16: #ifndef BOOST_NO_EXCEPTIONS
Chris@16:     if ( r == cNegOverflow )
Chris@16:       throw negative_overflow() ;
Chris@16:     else if ( r == cPosOverflow )
Chris@16:            throw positive_overflow() ;
Chris@16: #else
Chris@16:     if ( r == cNegOverflow )
Chris@16:       ::boost::throw_exception(negative_overflow()) ;
Chris@16:     else if ( r == cPosOverflow )
Chris@16:            ::boost::throw_exception(positive_overflow()) ;
Chris@16: #endif
Chris@16:   }
Chris@16: } ;
Chris@16: 
Chris@16: struct silent_overflow_handler
Chris@16: {
Chris@16:   void operator() ( range_check_result ) {} // throw()
Chris@16: } ;
Chris@16: 
Chris@16: template<class Traits>
Chris@16: struct raw_converter
Chris@16: {
Chris@16:   typedef typename Traits::result_type   result_type   ;
Chris@16:   typedef typename Traits::argument_type argument_type ;
Chris@16: 
Chris@16:   static result_type low_level_convert ( argument_type s ) { return static_cast<result_type>(s) ; }
Chris@16: } ;
Chris@16: 
Chris@16: struct UseInternalRangeChecker {} ;
Chris@16: 
Chris@16: } } // namespace boost::numeric
Chris@16: 
Chris@16: #endif