Chris@16: //  Boost common_factor_ct.hpp header file  ----------------------------------//
Chris@16: 
Chris@16: //  (C) Copyright Daryle Walker and Stephen Cleary 2001-2002.
Chris@16: //  Distributed under the Boost Software License, Version 1.0. (See
Chris@16: //  accompanying file LICENSE_1_0.txt or copy at
Chris@16: //  http://www.boost.org/LICENSE_1_0.txt)
Chris@16: 
Chris@16: //  See http://www.boost.org for updates, documentation, and revision history. 
Chris@16: 
Chris@16: #ifndef BOOST_MATH_COMMON_FACTOR_CT_HPP
Chris@16: #define BOOST_MATH_COMMON_FACTOR_CT_HPP
Chris@16: 
Chris@16: #include <boost/math_fwd.hpp>  // self include
Chris@16: #include <boost/config.hpp>  // for BOOST_STATIC_CONSTANT, etc.
Chris@16: #include <boost/mpl/integral_c.hpp>
Chris@16: 
Chris@16: namespace boost
Chris@16: {
Chris@16: namespace math
Chris@16: {
Chris@16: 
Chris@16: //  Implementation details  --------------------------------------------------//
Chris@16: 
Chris@16: namespace detail
Chris@16: {
Chris@16:     // Build GCD with Euclid's recursive algorithm
Chris@16:     template < static_gcd_type Value1, static_gcd_type Value2 >
Chris@16:     struct static_gcd_helper_t
Chris@16:     {
Chris@16:     private:
Chris@16:         BOOST_STATIC_CONSTANT( static_gcd_type, new_value1 = Value2 );
Chris@16:         BOOST_STATIC_CONSTANT( static_gcd_type, new_value2 = Value1 % Value2 );
Chris@16: 
Chris@16:         #ifndef __BORLANDC__
Chris@16:         #define BOOST_DETAIL_GCD_HELPER_VAL(Value) static_cast<static_gcd_type>(Value)
Chris@16:         #else
Chris@16:         typedef static_gcd_helper_t  self_type;
Chris@16:         #define BOOST_DETAIL_GCD_HELPER_VAL(Value)  (self_type:: Value )
Chris@16:         #endif
Chris@16: 
Chris@16:         typedef static_gcd_helper_t< BOOST_DETAIL_GCD_HELPER_VAL(new_value1),
Chris@16:          BOOST_DETAIL_GCD_HELPER_VAL(new_value2) >  next_step_type;
Chris@16: 
Chris@16:         #undef BOOST_DETAIL_GCD_HELPER_VAL
Chris@16: 
Chris@16:     public:
Chris@16:         BOOST_STATIC_CONSTANT( static_gcd_type, value = next_step_type::value );
Chris@16:     };
Chris@16: 
Chris@16:     // Non-recursive case
Chris@16:     template < static_gcd_type Value1 >
Chris@16:     struct static_gcd_helper_t< Value1, 0UL >
Chris@16:     {
Chris@16:         BOOST_STATIC_CONSTANT( static_gcd_type, value = Value1 );
Chris@16:     };
Chris@16: 
Chris@16:     // Build the LCM from the GCD
Chris@16:     template < static_gcd_type Value1, static_gcd_type Value2 >
Chris@16:     struct static_lcm_helper_t
Chris@16:     {
Chris@16:         typedef static_gcd_helper_t<Value1, Value2>  gcd_type;
Chris@16: 
Chris@16:         BOOST_STATIC_CONSTANT( static_gcd_type, value = Value1 / gcd_type::value
Chris@16:          * Value2 );
Chris@16:     };
Chris@16: 
Chris@16:     // Special case for zero-GCD values
Chris@16:     template < >
Chris@16:     struct static_lcm_helper_t< 0UL, 0UL >
Chris@16:     {
Chris@16:         BOOST_STATIC_CONSTANT( static_gcd_type, value = 0UL );
Chris@16:     };
Chris@16: 
Chris@16: }  // namespace detail
Chris@16: 
Chris@16: 
Chris@16: //  Compile-time greatest common divisor evaluator class declaration  --------//
Chris@16: 
Chris@16: template < static_gcd_type Value1, static_gcd_type Value2 >
Chris@16: struct static_gcd : public mpl::integral_c<static_gcd_type, (detail::static_gcd_helper_t<Value1, Value2>::value) >
Chris@16: {
Chris@16: };  // boost::math::static_gcd
Chris@16: 
Chris@16: 
Chris@16: //  Compile-time least common multiple evaluator class declaration  ----------//
Chris@16: 
Chris@16: template < static_gcd_type Value1, static_gcd_type Value2 >
Chris@16: struct static_lcm : public mpl::integral_c<static_gcd_type, (detail::static_lcm_helper_t<Value1, Value2>::value) >
Chris@16: {
Chris@16: };  // boost::math::static_lcm
Chris@16: 
Chris@16: 
Chris@16: }  // namespace math
Chris@16: }  // namespace boost
Chris@16: 
Chris@16: 
Chris@16: #endif  // BOOST_MATH_COMMON_FACTOR_CT_HPP