williamr@2: //  Boost common_factor_ct.hpp header file  ----------------------------------//
williamr@2: 
williamr@2: //  (C) Copyright Daryle Walker and Stephen Cleary 2001-2002.
williamr@2: //  Distributed under the Boost Software License, Version 1.0. (See
williamr@2: //  accompanying file LICENSE_1_0.txt or copy at
williamr@2: //  http://www.boost.org/LICENSE_1_0.txt)
williamr@2: 
williamr@2: //  See http://www.boost.org for updates, documentation, and revision history. 
williamr@2: 
williamr@2: #ifndef BOOST_MATH_COMMON_FACTOR_CT_HPP
williamr@2: #define BOOST_MATH_COMMON_FACTOR_CT_HPP
williamr@2: 
williamr@2: #include <boost/math_fwd.hpp>  // self include
williamr@2: 
williamr@2: #include <boost/config.hpp>  // for BOOST_STATIC_CONSTANT, etc.
williamr@2: 
williamr@2: 
williamr@2: namespace boost
williamr@2: {
williamr@2: namespace math
williamr@2: {
williamr@2: 
williamr@2: 
williamr@2: //  Implementation details  --------------------------------------------------//
williamr@2: 
williamr@2: namespace detail
williamr@2: {
williamr@2: #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2:     // Build GCD with Euclid's recursive algorithm
williamr@2:     template < unsigned long Value1, unsigned long Value2 >
williamr@2:     struct static_gcd_helper_t
williamr@2:     {
williamr@2:     private:
williamr@2:         BOOST_STATIC_CONSTANT( unsigned long, new_value1 = Value2 );
williamr@2:         BOOST_STATIC_CONSTANT( unsigned long, new_value2 = Value1 % Value2 );
williamr@2: 
williamr@2:         #ifndef __BORLANDC__
williamr@2:         #define BOOST_DETAIL_GCD_HELPER_VAL(Value) static_cast<unsigned long>(Value)
williamr@2:         #else
williamr@2:         typedef static_gcd_helper_t  self_type;
williamr@2:         #define BOOST_DETAIL_GCD_HELPER_VAL(Value)  (self_type:: Value )
williamr@2:         #endif
williamr@2: 
williamr@2:         typedef static_gcd_helper_t< BOOST_DETAIL_GCD_HELPER_VAL(new_value1),
williamr@2:          BOOST_DETAIL_GCD_HELPER_VAL(new_value2) >  next_step_type;
williamr@2: 
williamr@2:         #undef BOOST_DETAIL_GCD_HELPER_VAL
williamr@2: 
williamr@2:     public:
williamr@2:         BOOST_STATIC_CONSTANT( unsigned long, value = next_step_type::value );
williamr@2:     };
williamr@2: 
williamr@2:     // Non-recursive case
williamr@2:     template < unsigned long Value1 >
williamr@2:     struct static_gcd_helper_t< Value1, 0UL >
williamr@2:     {
williamr@2:         BOOST_STATIC_CONSTANT( unsigned long, value = Value1 );
williamr@2:     };
williamr@2: #else
williamr@2:     // Use inner class template workaround from Peter Dimov
williamr@2:     template < unsigned long Value1 >
williamr@2:     struct static_gcd_helper2_t
williamr@2:     {
williamr@2:         template < unsigned long Value2 >
williamr@2:         struct helper
williamr@2:         {
williamr@2:             BOOST_STATIC_CONSTANT( unsigned long, value
williamr@2:              = static_gcd_helper2_t<Value2>::BOOST_NESTED_TEMPLATE
williamr@2:              helper<Value1 % Value2>::value );
williamr@2:         };
williamr@2: 
williamr@2:         template <  >
williamr@2:         struct helper< 0UL >
williamr@2:         {
williamr@2:             BOOST_STATIC_CONSTANT( unsigned long, value = Value1 );
williamr@2:         };
williamr@2:     };
williamr@2: 
williamr@2:     // Special case
williamr@2:     template <  >
williamr@2:     struct static_gcd_helper2_t< 0UL >
williamr@2:     {
williamr@2:         template < unsigned long Value2 >
williamr@2:         struct helper
williamr@2:         {
williamr@2:             BOOST_STATIC_CONSTANT( unsigned long, value = Value2 );
williamr@2:         };
williamr@2:     };
williamr@2: 
williamr@2:     // Build the GCD from the above template(s)
williamr@2:     template < unsigned long Value1, unsigned long Value2 >
williamr@2:     struct static_gcd_helper_t
williamr@2:     {
williamr@2:         BOOST_STATIC_CONSTANT( unsigned long, value
williamr@2:          = static_gcd_helper2_t<Value1>::BOOST_NESTED_TEMPLATE
williamr@2:          helper<Value2>::value );
williamr@2:     };
williamr@2: #endif
williamr@2: 
williamr@2: #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2:     // Build the LCM from the GCD
williamr@2:     template < unsigned long Value1, unsigned long Value2 >
williamr@2:     struct static_lcm_helper_t
williamr@2:     {
williamr@2:         typedef static_gcd_helper_t<Value1, Value2>  gcd_type;
williamr@2: 
williamr@2:         BOOST_STATIC_CONSTANT( unsigned long, value = Value1 / gcd_type::value
williamr@2:          * Value2 );
williamr@2:     };
williamr@2: 
williamr@2:     // Special case for zero-GCD values
williamr@2:     template < >
williamr@2:     struct static_lcm_helper_t< 0UL, 0UL >
williamr@2:     {
williamr@2:         BOOST_STATIC_CONSTANT( unsigned long, value = 0UL );
williamr@2:     };
williamr@2: #else
williamr@2:     // Adapt GCD's inner class template workaround for LCM
williamr@2:     template < unsigned long Value1 >
williamr@2:     struct static_lcm_helper2_t
williamr@2:     {
williamr@2:         template < unsigned long Value2 >
williamr@2:         struct helper
williamr@2:         {
williamr@2:             typedef static_gcd_helper_t<Value1, Value2>  gcd_type;
williamr@2: 
williamr@2:             BOOST_STATIC_CONSTANT( unsigned long, value = Value1
williamr@2:              / gcd_type::value * Value2 );
williamr@2:         };
williamr@2: 
williamr@2:         template <  >
williamr@2:         struct helper< 0UL >
williamr@2:         {
williamr@2:             BOOST_STATIC_CONSTANT( unsigned long, value = 0UL );
williamr@2:         };
williamr@2:     };
williamr@2: 
williamr@2:     // Special case
williamr@2:     template <  >
williamr@2:     struct static_lcm_helper2_t< 0UL >
williamr@2:     {
williamr@2:         template < unsigned long Value2 >
williamr@2:         struct helper
williamr@2:         {
williamr@2:             BOOST_STATIC_CONSTANT( unsigned long, value = 0UL );
williamr@2:         };
williamr@2:     };
williamr@2: 
williamr@2:     // Build the LCM from the above template(s)
williamr@2:     template < unsigned long Value1, unsigned long Value2 >
williamr@2:     struct static_lcm_helper_t
williamr@2:     {
williamr@2:         BOOST_STATIC_CONSTANT( unsigned long, value
williamr@2:          = static_lcm_helper2_t<Value1>::BOOST_NESTED_TEMPLATE
williamr@2:          helper<Value2>::value );
williamr@2:     };
williamr@2: #endif
williamr@2: 
williamr@2: }  // namespace detail
williamr@2: 
williamr@2: 
williamr@2: //  Compile-time greatest common divisor evaluator class declaration  --------//
williamr@2: 
williamr@2: template < unsigned long Value1, unsigned long Value2 >
williamr@2: struct static_gcd
williamr@2: {
williamr@2:     BOOST_STATIC_CONSTANT( unsigned long, value
williamr@2:      = (detail::static_gcd_helper_t<Value1, Value2>::value) );
williamr@2: 
williamr@2: };  // boost::math::static_gcd
williamr@2: 
williamr@2: 
williamr@2: //  Compile-time least common multiple evaluator class declaration  ----------//
williamr@2: 
williamr@2: template < unsigned long Value1, unsigned long Value2 >
williamr@2: struct static_lcm
williamr@2: {
williamr@2:     BOOST_STATIC_CONSTANT( unsigned long, value
williamr@2:      = (detail::static_lcm_helper_t<Value1, Value2>::value) );
williamr@2: 
williamr@2: };  // boost::math::static_lcm
williamr@2: 
williamr@2: 
williamr@2: }  // namespace math
williamr@2: }  // namespace boost
williamr@2: 
williamr@2: 
williamr@2: #endif  // BOOST_MATH_COMMON_FACTOR_CT_HPP