1 | // Boost common_factor_ct.hpp header file ----------------------------------// |
2 | |
3 | // (C) Copyright Daryle Walker and Stephen Cleary 2001-2002. |
4 | // Distributed under the Boost Software License, Version 1.0. (See |
5 | // accompanying file LICENSE_1_0.txt or copy at |
6 | // http://www.boost.org/LICENSE_1_0.txt) |
7 | |
8 | // See http://www.boost.org for updates, documentation, and revision history. |
9 | |
10 | #ifndef BOOST_MATH_COMMON_FACTOR_CT_HPP |
11 | #define BOOST_MATH_COMMON_FACTOR_CT_HPP |
12 | |
13 | #include <boost/math_fwd.hpp> // self include |
14 | #include <boost/config.hpp> // for BOOST_STATIC_CONSTANT, etc. |
15 | #include <boost/mpl/integral_c.hpp> |
16 | |
17 | namespace boost |
18 | { |
19 | namespace math |
20 | { |
21 | |
22 | // Implementation details --------------------------------------------------// |
23 | |
24 | namespace detail |
25 | { |
26 | // Build GCD with Euclid's recursive algorithm |
27 | template < static_gcd_type Value1, static_gcd_type Value2 > |
28 | struct static_gcd_helper_t |
29 | { |
30 | private: |
31 | BOOST_STATIC_CONSTANT( static_gcd_type, new_value1 = Value2 ); |
32 | BOOST_STATIC_CONSTANT( static_gcd_type, new_value2 = Value1 % Value2 ); |
33 | |
34 | #ifndef __BORLANDC__ |
35 | #define BOOST_DETAIL_GCD_HELPER_VAL(Value) static_cast<static_gcd_type>(Value) |
36 | #else |
37 | typedef static_gcd_helper_t self_type; |
38 | #define BOOST_DETAIL_GCD_HELPER_VAL(Value) (self_type:: Value ) |
39 | #endif |
40 | |
41 | typedef static_gcd_helper_t< BOOST_DETAIL_GCD_HELPER_VAL(new_value1), |
42 | BOOST_DETAIL_GCD_HELPER_VAL(new_value2) > next_step_type; |
43 | |
44 | #undef BOOST_DETAIL_GCD_HELPER_VAL |
45 | |
46 | public: |
47 | BOOST_STATIC_CONSTANT( static_gcd_type, value = next_step_type::value ); |
48 | }; |
49 | |
50 | // Non-recursive case |
51 | template < static_gcd_type Value1 > |
52 | struct static_gcd_helper_t< Value1, 0UL > |
53 | { |
54 | BOOST_STATIC_CONSTANT( static_gcd_type, value = Value1 ); |
55 | }; |
56 | |
57 | // Build the LCM from the GCD |
58 | template < static_gcd_type Value1, static_gcd_type Value2 > |
59 | struct static_lcm_helper_t |
60 | { |
61 | typedef static_gcd_helper_t<Value1, Value2> gcd_type; |
62 | |
63 | BOOST_STATIC_CONSTANT( static_gcd_type, value = Value1 / gcd_type::value |
64 | * Value2 ); |
65 | }; |
66 | |
67 | // Special case for zero-GCD values |
68 | template < > |
69 | struct static_lcm_helper_t< 0UL, 0UL > |
70 | { |
71 | BOOST_STATIC_CONSTANT( static_gcd_type, value = 0UL ); |
72 | }; |
73 | |
74 | } // namespace detail |
75 | |
76 | |
77 | // Compile-time greatest common divisor evaluator class declaration --------// |
78 | |
79 | template < static_gcd_type Value1, static_gcd_type Value2 > |
80 | struct static_gcd : public mpl::integral_c<static_gcd_type, (detail::static_gcd_helper_t<Value1, Value2>::value) > |
81 | { |
82 | }; // boost::math::static_gcd |
83 | |
84 | |
85 | // Compile-time least common multiple evaluator class declaration ----------// |
86 | |
87 | template < static_gcd_type Value1, static_gcd_type Value2 > |
88 | struct static_lcm : public mpl::integral_c<static_gcd_type, (detail::static_lcm_helper_t<Value1, Value2>::value) > |
89 | { |
90 | }; // boost::math::static_lcm |
91 | |
92 | |
93 | } // namespace math |
94 | } // namespace boost |
95 | |
96 | |
97 | #endif // BOOST_MATH_COMMON_FACTOR_CT_HPP |
98 | |