test_default_conversion.cpp

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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)

#include <boost/test/minimal.hpp>

#include <boost/units/base_dimension.hpp>
#include <boost/units/base_unit.hpp>
#include <boost/units/scaled_base_unit.hpp>
#include <boost/units/conversion.hpp>
#include <boost/units/unit.hpp>

struct dimension1_tag : boost::units::base_dimension<dimension1_tag, 1> {};

typedef dimension1_tag::dimension_type dimension1;

struct dimension2_tag : boost::units::base_dimension<dimension2_tag, 2> {};

typedef dimension2_tag::dimension_type dimension2;

typedef boost::mpl::times<dimension1, dimension2>::type dimension12;

struct unit1_tag : boost::units::base_unit<unit1_tag, dimension1, 1> {}; 

struct unit2_tag : boost::units::base_unit<unit2_tag, dimension1, 2> {};

struct unit3_tag : boost::units::base_unit<unit3_tag, dimension1, 3> {};

struct unit4_tag : boost::units::base_unit<unit4_tag, dimension2, 4> {};

struct unit5_tag : boost::units::base_unit<unit5_tag, dimension12, 5> {};

BOOST_UNITS_DEFINE_CONVERSION_FACTOR(unit1_tag, unit2_tag, double, 2.0);

BOOST_UNITS_DEFINE_CONVERSION_FACTOR(unit2_tag, unit3_tag, double, 3.0);

typedef boost::units::multiply_typeof_helper<unit3_tag::unit_type, unit4_tag::unit_type>::type unit34_type;
BOOST_UNITS_DEFINE_CONVERSION_FACTOR(unit5_tag, unit34_type , double, 5.0);

BOOST_UNITS_DEFAULT_CONVERSION(unit1_tag, unit2_tag::unit_type);

BOOST_UNITS_DEFAULT_CONVERSION(unit3_tag, unit2_tag::unit_type);

BOOST_UNITS_DEFAULT_CONVERSION(unit5_tag, unit34_type);

int test_main(int, char*[]) {
    double value1 = boost::units::conversion_factor(unit3_tag::unit_type(), unit1_tag::unit_type());
    BOOST_CHECK(std::abs(value1 - 1.0/6.0) < .0000000001);
    double value2 = boost::units::conversion_factor(unit5_tag::unit_type() / unit4_tag::unit_type(), unit1_tag::unit_type());
    BOOST_CHECK(std::abs(value2 - 5.0/6.0) < .0000000001);
    typedef boost::units::scaled_base_unit<unit5_tag, boost::units::scale<2, boost::units::static_rational<1> > > scaled_unit5_tag;
    double value3 = boost::units::conversion_factor(scaled_unit5_tag::unit_type() / unit4_tag::unit_type(), unit1_tag::unit_type());
    BOOST_CHECK(std::abs(value3 - 10.0/6.0) < .0000000001);
    return(0);
}