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- // Boost.Units - A C++ library for zero-overhead dimensional analysis and
- // unit/quantity manipulation and conversion
- //
- // Copyright (C) 2003-2008 Matthias Christian Schabel
- // Copyright (C) 2008 Steven Watanabe
- //
- // 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)
- ///
- /// \file
- /// \brief Absolute units (points rather than vectors).
- /// \details Operations between absolute units, and relative units like temperature differences.
- ///
- #ifndef BOOST_UNITS_ABSOLUTE_HPP
- #define BOOST_UNITS_ABSOLUTE_HPP
- #include <iosfwd>
- #include <boost/units/detail/absolute_impl.hpp>
- namespace boost {
- namespace units {
- /// A wrapper to represent absolute units (points rather than vectors). Intended
- /// originally for temperatures, this class implements operators for absolute units
- /// so that addition of a relative unit to an absolute unit results in another
- /// absolute unit : absolute<T> +/- T -> absolute<T> and subtraction of one absolute
- /// unit from another results in a relative unit : absolute<T> - absolute<T> -> T.
- template<class Y>
- class absolute
- {
- public:
- typedef absolute<Y> this_type;
- typedef Y value_type;
-
- BOOST_CONSTEXPR absolute() : val_() { }
- BOOST_CONSTEXPR absolute(const value_type& val) : val_(val) { }
- BOOST_CONSTEXPR absolute(const this_type& source) : val_(source.val_) { }
-
- BOOST_CXX14_CONSTEXPR this_type& operator=(const this_type& source) { val_ = source.val_; return *this; }
-
- BOOST_CONSTEXPR const value_type& value() const { return val_; }
-
- BOOST_CXX14_CONSTEXPR const this_type& operator+=(const value_type& val) { val_ += val; return *this; }
- BOOST_CXX14_CONSTEXPR const this_type& operator-=(const value_type& val) { val_ -= val; return *this; }
-
- private:
- value_type val_;
- };
- /// add a relative value to an absolute one
- template<class Y>
- BOOST_CONSTEXPR absolute<Y> operator+(const absolute<Y>& aval,const Y& rval)
- {
- return absolute<Y>(aval.value()+rval);
- }
- /// add a relative value to an absolute one
- template<class Y>
- BOOST_CONSTEXPR absolute<Y> operator+(const Y& rval,const absolute<Y>& aval)
- {
- return absolute<Y>(aval.value()+rval);
- }
- /// subtract a relative value from an absolute one
- template<class Y>
- BOOST_CONSTEXPR absolute<Y> operator-(const absolute<Y>& aval,const Y& rval)
- {
- return absolute<Y>(aval.value()-rval);
- }
- /// subtracting two absolutes gives a difference
- template<class Y>
- BOOST_CONSTEXPR Y operator-(const absolute<Y>& aval1,const absolute<Y>& aval2)
- {
- return Y(aval1.value()-aval2.value());
- }
- /// creates a quantity from an absolute unit and a raw value
- template<class D, class S, class T>
- BOOST_CONSTEXPR quantity<absolute<unit<D, S> >, T> operator*(const T& t, const absolute<unit<D, S> >&)
- {
- return(quantity<absolute<unit<D, S> >, T>::from_value(t));
- }
- /// creates a quantity from an absolute unit and a raw value
- template<class D, class S, class T>
- BOOST_CONSTEXPR quantity<absolute<unit<D, S> >, T> operator*(const absolute<unit<D, S> >&, const T& t)
- {
- return(quantity<absolute<unit<D, S> >, T>::from_value(t));
- }
- /// Print an absolute unit
- template<class Char, class Traits, class Y>
- std::basic_ostream<Char, Traits>& operator<<(std::basic_ostream<Char, Traits>& os,const absolute<Y>& aval)
- {
- os << "absolute " << aval.value();
-
- return os;
- }
- } // namespace units
- } // namespace boost
- #if BOOST_UNITS_HAS_BOOST_TYPEOF
- #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP()
- BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::absolute, (class))
- #endif
- namespace boost {
- namespace units {
- /// Macro to define the offset between two absolute units.
- /// Requires the value to be in the destination units e.g
- /// @code
- /// BOOST_UNITS_DEFINE_CONVERSION_OFFSET(celsius_base_unit, fahrenheit_base_unit, double, 32.0);
- /// @endcode
- /// @c BOOST_UNITS_DEFINE_CONVERSION_FACTOR is also necessary to
- /// specify the conversion factor. Like @c BOOST_UNITS_DEFINE_CONVERSION_FACTOR
- /// this macro defines both forward and reverse conversions so
- /// defining, e.g., the conversion from celsius to fahrenheit as above will also
- /// define the inverse conversion from fahrenheit to celsius.
- #define BOOST_UNITS_DEFINE_CONVERSION_OFFSET(From, To, type_, value_) \
- namespace boost { \
- namespace units { \
- template<> \
- struct affine_conversion_helper< \
- reduce_unit<From::unit_type>::type, \
- reduce_unit<To::unit_type>::type> \
- { \
- BOOST_STATIC_CONSTEXPR bool is_defined = true; \
- typedef type_ type; \
- static BOOST_CONSTEXPR type value() { return(value_); } \
- }; \
- } \
- } \
- void boost_units_require_semicolon()
- } // namespace units
- } // namespace boost
- #endif // BOOST_UNITS_ABSOLUTE_HPP
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