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