units/detail/one.hpp

0001 // Boost.Units - A C++ library for zero-overhead dimensional analysis and
0002 // unit/quantity manipulation and conversion
0003 //
0004 // Copyright (C) 2003-2008 Matthias Christian Schabel
0005 // Copyright (C) 2008 Steven Watanabe
0006 //
0007 // Distributed under the Boost Software License, Version 1.0. (See
0008 // accompanying file LICENSE_1_0.txt or copy at
0009 // http://www.boost.org/LICENSE_1_0.txt)
0010
0011 #ifndef BOOST_UNITS_DETAIL_ONE_HPP
0012 #define BOOST_UNITS_DETAIL_ONE_HPP
0013
0014 #include <boost/units/operators.hpp>
0015
0016 namespace boost {
0017
0018 namespace units {
0019
0020 struct one { BOOST_CONSTEXPR one() {} };
0021
0022 // workaround for pathscale.
0023 inline BOOST_CONSTEXPR one make_one() {
0024     return(one());
0025 }
0026
0027 template<class T>
0028 struct multiply_typeof_helper<one, T>
0029 {
0030     typedef T type;
0031 };
0032
0033 template<class T>
0034 struct multiply_typeof_helper<T, one>
0035 {
0036     typedef T type;
0037 };
0038
0039 template<>
0040 struct multiply_typeof_helper<one, one>
0041 {
0042     typedef one type;
0043 };
0044
0045 template<class T>
0046 inline BOOST_CONSTEXPR T operator*(const one&, const T& t)
0047 {
0048     return(t);
0049 }
0050
0051 template<class T>
0052 inline BOOST_CONSTEXPR T operator*(const T& t, const one&)
0053 {
0054     return(t);
0055 }
0056
0057 inline BOOST_CONSTEXPR one operator*(const one&, const one&)
0058 {
0059     return(one());
0060 }
0061
0062 template<class T>
0063 struct divide_typeof_helper<T, one>
0064 {
0065     typedef T type;
0066 };
0067
0068 template<class T>
0069 struct divide_typeof_helper<one, T>
0070 {
0071     typedef T type;
0072 };
0073
0074 template<>
0075 struct divide_typeof_helper<one, one>
0076 {
0077     typedef one type;
0078 };
0079
0080 template<class T>
0081 inline BOOST_CONSTEXPR T operator/(const T& t, const one&)
0082 {
0083     return(t);
0084 }
0085
0086 template<class T>
0087 inline BOOST_CONSTEXPR T operator/(const one&, const T& t)
0088 {
0089     return(1/t);
0090 }
0091
0092 inline BOOST_CONSTEXPR one operator/(const one&, const one&)
0093 {
0094     return(one());
0095 }
0096
0097 template<class T>
0098 inline BOOST_CONSTEXPR bool operator>(const boost::units::one&, const T& t) {
0099     return(1 > t);
0100 }
0101
0102 template<class T>
0103 BOOST_CONSTEXPR T one_to_double(const T& t) { return t; }
0104
0105 inline BOOST_CONSTEXPR double one_to_double(const one&) { return 1.0; }
0106
0107 template<class T>
0108 struct one_to_double_type { typedef T type; };
0109
0110 template<>
0111 struct one_to_double_type<one> { typedef double type; };
0112
0113 } // namespace units
0114
0115 } // namespace boost
0116
0117 #endif