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153 lines
5.2 KiB
153 lines
5.2 KiB
// Boost.Units - A C++ library for zero-overhead dimensional analysis and |
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// unit/quantity manipulation and conversion |
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// |
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// Copyright (C) 2003-2008 Matthias Christian Schabel |
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// Copyright (C) 2008 Steven Watanabe |
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// |
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// Distributed under the Boost Software License, Version 1.0. (See |
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// accompanying file LICENSE_1_0.txt or copy at |
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// http://www.boost.org/LICENSE_1_0.txt) |
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/// |
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/// \file |
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/// \brief Absolute units (points rather than vectors). |
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/// \details Operations between absolute units, and relative units like temperature differences. |
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/// |
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#ifndef BOOST_UNITS_ABSOLUTE_HPP |
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#define BOOST_UNITS_ABSOLUTE_HPP |
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#include <iosfwd> |
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#include <boost/units/detail/absolute_impl.hpp> |
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namespace boost { |
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namespace units { |
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/// A wrapper to represent absolute units (points rather than vectors). Intended |
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/// originally for temperatures, this class implements operators for absolute units |
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/// so that addition of a relative unit to an absolute unit results in another |
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/// absolute unit : absolute<T> +/- T -> absolute<T> and subtraction of one absolute |
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/// unit from another results in a relative unit : absolute<T> - absolute<T> -> T. |
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template<class Y> |
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class absolute |
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{ |
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public: |
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typedef absolute<Y> this_type; |
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typedef Y value_type; |
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absolute() : val_() { } |
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absolute(const value_type& val) : val_(val) { } |
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absolute(const this_type& source) : val_(source.val_) { } |
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this_type& operator=(const this_type& source) { val_ = source.val_; return *this; } |
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const value_type& value() const { return val_; } |
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const this_type& operator+=(const value_type& val) { val_ += val; return *this; } |
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const this_type& operator-=(const value_type& val) { val_ -= val; return *this; } |
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private: |
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value_type val_; |
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}; |
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/// add a relative value to an absolute one |
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template<class Y> |
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absolute<Y> operator+(const absolute<Y>& aval,const Y& rval) |
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{ |
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return absolute<Y>(aval.value()+rval); |
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} |
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/// add a relative value to an absolute one |
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template<class Y> |
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absolute<Y> operator+(const Y& rval,const absolute<Y>& aval) |
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{ |
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return absolute<Y>(aval.value()+rval); |
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} |
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/// subtract a relative value from an absolute one |
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template<class Y> |
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absolute<Y> operator-(const absolute<Y>& aval,const Y& rval) |
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{ |
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return absolute<Y>(aval.value()-rval); |
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} |
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/// subtracting two absolutes gives a difference |
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template<class Y> |
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Y operator-(const absolute<Y>& aval1,const absolute<Y>& aval2) |
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{ |
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return Y(aval1.value()-aval2.value()); |
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} |
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/// creates a quantity from an absolute unit and a raw value |
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template<class D, class S, class T> |
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quantity<absolute<unit<D, S> >, T> operator*(const T& t, const absolute<unit<D, S> >&) |
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{ |
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return(quantity<absolute<unit<D, S> >, T>::from_value(t)); |
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} |
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/// creates a quantity from an absolute unit and a raw value |
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template<class D, class S, class T> |
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quantity<absolute<unit<D, S> >, T> operator*(const absolute<unit<D, S> >&, const T& t) |
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{ |
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return(quantity<absolute<unit<D, S> >, T>::from_value(t)); |
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} |
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/// Print an absolute unit |
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template<class Char, class Traits, class Y> |
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std::basic_ostream<Char, Traits>& operator<<(std::basic_ostream<Char, Traits>& os,const absolute<Y>& aval) |
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{ |
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os << "absolute " << aval.value(); |
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return os; |
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} |
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} // namespace units |
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} // namespace boost |
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#if BOOST_UNITS_HAS_BOOST_TYPEOF |
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#include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() |
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BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::absolute, (class)) |
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#endif |
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namespace boost { |
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namespace units { |
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/// Macro to define the offset between two absolute units. |
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/// Requires the value to be in the destination units e.g |
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/// @code |
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/// BOOST_UNITS_DEFINE_CONVERSION_OFFSET(celsius_base_unit, fahrenheit_base_unit, double, 32.0); |
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/// @endcode |
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/// @c BOOST_UNITS_DEFINE_CONVERSION_FACTOR is also necessary to |
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/// specify the conversion factor. Like @c BOOST_UNITS_DEFINE_CONVERSION_FACTOR |
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/// this macro defines both forward and reverse conversions so |
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/// defining, e.g., the conversion from celsius to fahrenheit as above will also |
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/// define the inverse conversion from fahrenheit to celsius. |
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#define BOOST_UNITS_DEFINE_CONVERSION_OFFSET(From, To, type_, value_) \ |
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namespace boost { \ |
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namespace units { \ |
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template<> \ |
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struct affine_conversion_helper< \ |
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reduce_unit<From::unit_type>::type, \ |
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reduce_unit<To::unit_type>::type> \ |
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{ \ |
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static const bool is_defined = true; \ |
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typedef type_ type; \ |
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static type value() { return(value_); } \ |
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}; \ |
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} \ |
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} \ |
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void boost_units_require_semicolon() |
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} // namespace units |
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} // namespace boost |
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#endif // BOOST_UNITS_ABSOLUTE_HPP
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