]>
Commit | Line | Data |
---|---|---|
7c673cae FG |
1 | // Boost.Units - A C++ library for zero-overhead dimensional analysis and |
2 | // unit/quantity manipulation and conversion | |
3 | // | |
4 | // Copyright (C) 2003-2008 Matthias Christian Schabel | |
5 | // Copyright (C) 2008 Steven Watanabe | |
6 | // | |
7 | // Distributed under the Boost Software License, Version 1.0. (See | |
8 | // accompanying file LICENSE_1_0.txt or copy at | |
9 | // http://www.boost.org/LICENSE_1_0.txt) | |
10 | ||
11 | #ifndef BOOST_UNITS_DIM_IMPL_HPP | |
12 | #define BOOST_UNITS_DIM_IMPL_HPP | |
13 | ||
14 | #include <boost/mpl/bool.hpp> | |
15 | #include <boost/mpl/less.hpp> | |
16 | ||
17 | #include <boost/units/units_fwd.hpp> | |
18 | ||
19 | /// \file | |
20 | /// \brief Class encapsulating a dimension tag/value pair | |
21 | ||
22 | namespace boost { | |
23 | ||
24 | namespace units { | |
25 | ||
26 | namespace detail { | |
27 | ||
28 | struct dim_tag; | |
29 | ||
30 | } | |
31 | ||
32 | } | |
33 | ||
34 | namespace mpl { | |
35 | ||
36 | /// Less than comparison for sorting @c dim. | |
37 | template<> | |
38 | struct less_impl<boost::units::detail::dim_tag, boost::units::detail::dim_tag> | |
39 | { | |
40 | template<class T0, class T1> | |
41 | struct apply : mpl::less<typename T0::tag_type, typename T1::tag_type> {}; | |
42 | }; | |
43 | ||
44 | } | |
45 | ||
46 | namespace units { | |
47 | ||
48 | template<class Tag, class Exponent> | |
49 | struct dim; | |
50 | ||
51 | template<long N, long D> | |
52 | class static_rational; | |
53 | ||
54 | namespace detail { | |
55 | ||
56 | /// Extract @c tag_type from a @c dim. | |
57 | template<typename T> | |
58 | struct get_tag | |
59 | { | |
60 | typedef typename T::tag_type type; | |
61 | }; | |
62 | ||
63 | /// Extract @c value_type from a @c dim. | |
64 | template<typename T> | |
65 | struct get_value | |
66 | { | |
67 | typedef typename T::value_type type; | |
68 | }; | |
69 | ||
70 | /// Determine if a @c dim is empty (has a zero exponent). | |
71 | template<class T> | |
72 | struct is_empty_dim; | |
73 | ||
74 | template<typename T> | |
75 | struct is_empty_dim< dim<T, static_rational<0, 1> > > : | |
76 | mpl::true_ | |
77 | { }; | |
78 | ||
79 | template<typename T, typename V> | |
80 | struct is_empty_dim< dim<T, V> > : | |
81 | mpl::false_ | |
82 | { }; | |
83 | ||
84 | } // namespace detail | |
85 | ||
86 | } // namespace units | |
87 | ||
88 | } // namespace boost | |
89 | ||
90 | #endif // BOOST_UNITS_DIM_IMPL_HPP |