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- //
- //! Copyright (c) 2011
- //! Brandon Kohn
- //
- // Distributed under 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)
- //
- #include <boost/operators.hpp>
- #include <boost/numeric/conversion/cast.hpp>
- #include <boost/mpl/for_each.hpp>
- #include <boost/mpl/vector.hpp>
- #include <boost/cstdint.hpp>
- #include <boost/test/minimal.hpp>
- //! Define a simple custom number
- struct Double
- {
- Double()
- : v(0)
- {}
- template <typename T>
- explicit Double( T v )
- : v(static_cast<double>(v))
- {}
- template <typename T>
- Double& operator= ( T t )
- {
- v = static_cast<double>(t);
- return *this;
- }
- bool operator < ( const Double& rhs ) const
- {
- return v < rhs.v;
- }
- template <typename T>
- bool operator < ( T rhs ) const
- {
- return v < static_cast<double>(rhs);
- }
- template <typename LHS>
- friend bool operator < ( const LHS& lhs, const Double& rhs )
- {
- return lhs < rhs.v;
- }
- bool operator > ( const Double& rhs ) const
- {
- return v > rhs.v;
- }
- template <typename LHS>
- friend bool operator > ( const LHS& lhs, const Double& rhs )
- {
- return lhs > rhs.v;
- }
-
- template <typename T>
- bool operator > ( T rhs ) const
- {
- return v > static_cast<double>(rhs);
- }
-
- bool operator == ( const Double& rhs ) const
- {
- return v == rhs.v;
- }
-
- template <typename T>
- bool operator == ( T rhs ) const
- {
- return v == static_cast<double>(rhs);
- }
- template <typename LHS>
- friend bool operator == ( const LHS& lhs, const Double& rhs )
- {
- return lhs == rhs.v;
- }
-
- bool operator !() const
- {
- return v == 0;
- }
-
- Double operator -() const
- {
- return Double(-v);
- }
-
- Double& operator +=( const Double& t )
- {
- v += t.v;
- return *this;
- }
-
- template <typename T>
- Double& operator +=( T t )
- {
- v += static_cast<double>(t);
- return *this;
- }
-
- Double& operator -=( const Double& t )
- {
- v -= t.v;
- return *this;
- }
-
- template <typename T>
- Double& operator -=( T t )
- {
- v -= static_cast<double>(t);
- return *this;
- }
-
- Double& operator *= ( const Double& factor )
- {
- v *= factor.v;
- return *this;
- }
-
- template <typename T>
- Double& operator *=( T t )
- {
- v *= static_cast<double>(t);
- return *this;
- }
- Double& operator /= (const Double& divisor)
- {
- v /= divisor.v;
- return *this;
- }
-
- template <typename T>
- Double& operator /=( T t )
- {
- v /= static_cast<double>(t);
- return (*this);
- }
-
- double v;
- };
- //! Define numeric_limits for the custom type.
- namespace std
- {
- template<>
- class numeric_limits< Double > : public numeric_limits<double>
- {
- public:
- //! Limit our Double to a range of +/- 100.0
- static Double (min)()
- {
- return Double(1.e-2);
- }
- static Double (max)()
- {
- return Double(1.e2);
- }
- static Double epsilon()
- {
- return Double( std::numeric_limits<double>::epsilon() );
- }
- };
- }
- //! Define range checking and overflow policies.
- namespace custom
- {
- //! Define a custom range checker
- template<typename Traits, typename OverFlowHandler>
- struct range_checker
- {
- typedef typename Traits::argument_type argument_type ;
- typedef typename Traits::source_type S;
- typedef typename Traits::target_type T;
-
- //! Check range of integral types.
- static boost::numeric::range_check_result out_of_range( argument_type s )
- {
- using namespace boost::numeric;
- if( s > bounds<T>::highest() )
- return cPosOverflow;
- else if( s < bounds<T>::lowest() )
- return cNegOverflow;
- else
- return cInRange;
- }
- static void validate_range ( argument_type s )
- {
- BOOST_STATIC_ASSERT( std::numeric_limits<T>::is_bounded );
- OverFlowHandler()( out_of_range(s) );
- }
- };
- //! Overflow handler
- struct positive_overflow{};
- struct negative_overflow{};
- struct overflow_handler
- {
- void operator() ( boost::numeric::range_check_result r )
- {
- using namespace boost::numeric;
- if( r == cNegOverflow )
- throw negative_overflow() ;
- else if( r == cPosOverflow )
- throw positive_overflow() ;
- }
- };
- //! Define a rounding policy and specialize on the custom type.
- template<class S>
- struct Ceil : boost::numeric::Ceil<S>{};
- template<>
- struct Ceil<Double>
- {
- typedef Double source_type;
- typedef Double const& argument_type;
- static source_type nearbyint ( argument_type s )
- {
- #if !defined(BOOST_NO_STDC_NAMESPACE)
- using std::ceil ;
- #endif
- return Double( ceil(s.v) );
- }
- typedef boost::mpl::integral_c< std::float_round_style, std::round_toward_infinity> round_style;
- };
- //! Define a rounding policy and specialize on the custom type.
- template<class S>
- struct Trunc: boost::numeric::Trunc<S>{};
- template<>
- struct Trunc<Double>
- {
- typedef Double source_type;
- typedef Double const& argument_type;
- static source_type nearbyint ( argument_type s )
- {
- #if !defined(BOOST_NO_STDC_NAMESPACE)
- using std::floor;
- #endif
- return Double( floor(s.v) );
- }
- typedef boost::mpl::integral_c< std::float_round_style, std::round_toward_zero> round_style;
- };
- }//namespace custom;
- namespace boost { namespace numeric {
- //! Define the numeric_cast_traits specializations on the custom type.
- template <typename S>
- struct numeric_cast_traits<Double, S>
- {
- typedef custom::overflow_handler overflow_policy;
- typedef custom::range_checker
- <
- boost::numeric::conversion_traits<Double, S>
- , overflow_policy
- > range_checking_policy;
- typedef boost::numeric::Trunc<S> rounding_policy;
- };
-
- template <typename T>
- struct numeric_cast_traits<T, Double>
- {
- typedef custom::overflow_handler overflow_policy;
- typedef custom::range_checker
- <
- boost::numeric::conversion_traits<T, Double>
- , overflow_policy
- > range_checking_policy;
- typedef custom::Trunc<Double> rounding_policy;
- };
- //! Define the conversion from the custom type to built-in types and vice-versa.
- template<typename T>
- struct raw_converter< conversion_traits< T, Double > >
- {
- static T low_level_convert ( const Double& n )
- {
- return static_cast<T>( n.v );
- }
- };
- template<typename S>
- struct raw_converter< conversion_traits< Double, S > >
- {
- static Double low_level_convert ( const S& n )
- {
- return Double(n);
- }
- };
- }}//namespace boost::numeric;
- #define BOOST_TEST_CATCH_CUSTOM_POSITIVE_OVERFLOW( CastCode ) \
- try { CastCode; BOOST_CHECK( false ); } \
- catch( custom::positive_overflow& ){} \
- catch(...){ BOOST_CHECK( false ); } \
- /***/
- #define BOOST_TEST_CATCH_CUSTOM_NEGATIVE_OVERFLOW( CastCode ) \
- try { CastCode; BOOST_CHECK( false ); } \
- catch( custom::negative_overflow& ){} \
- catch(...){ BOOST_CHECK( false ); } \
- /***/
- struct test_cast_traits
- {
- template <typename T>
- void operator()(T) const
- {
- Double d = boost::numeric_cast<Double>( static_cast<T>(50) );
- BOOST_CHECK( d.v == 50. );
- T v = boost::numeric_cast<T>( d );
- BOOST_CHECK( v == 50 );
- }
- };
- void test_numeric_cast_traits()
- {
- typedef boost::mpl::vector
- <
- boost::int8_t
- , boost::uint8_t
- , boost::int16_t
- , boost::uint16_t
- , boost::int32_t
- , boost::uint32_t
- #if !defined( BOOST_NO_INT64_T )
- , boost::int64_t
- , boost::uint64_t
- #endif
- , float
- , double
- , long double
- > types;
- boost::mpl::for_each<types>( test_cast_traits() );
-
- //! Check overflow handler.
- Double d( 56.0 );
- BOOST_TEST_CATCH_CUSTOM_POSITIVE_OVERFLOW( d = boost::numeric_cast<Double>( 101 ) );
- BOOST_CHECK( d.v == 56. );
- BOOST_TEST_CATCH_CUSTOM_NEGATIVE_OVERFLOW( d = boost::numeric_cast<Double>( -101 ) );
- BOOST_CHECK( d.v == 56.);
- //! Check custom round policy.
- d = 5.9;
- int five = boost::numeric_cast<int>( d );
- BOOST_CHECK( five == 5 );
- }
- int test_main( int argc, char * argv[] )
- {
- test_numeric_cast_traits();
- return 0;
- }
- #undef BOOST_TEST_CATCH_CUSTOM_POSITIVE_OVERFLOW
- #undef BOOST_TEST_CATCH_CUSTOM_NEGATIVE_OVERFLOW
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