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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands. | |
4 | // Copyright (c) 2011-2012 Bruno Lalande, Paris, France. | |
5 | // Copyright (c) 2011-2012 Mateusz Loskot, London, UK. | |
6 | ||
7 | // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library | |
8 | // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands. | |
9 | ||
10 | // Use, modification and distribution is subject to the Boost Software License, | |
11 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
12 | // http://www.boost.org/LICENSE_1_0.txt) | |
13 | ||
14 | #ifndef BOOST_GEOMETRY_UTIL_RATIONAL_HPP | |
15 | #define BOOST_GEOMETRY_UTIL_RATIONAL_HPP | |
16 | ||
17 | #include <boost/rational.hpp> | |
18 | #include <boost/numeric/conversion/bounds.hpp> | |
19 | ||
20 | #include <boost/geometry/util/coordinate_cast.hpp> | |
21 | #include <boost/geometry/util/select_most_precise.hpp> | |
22 | ||
23 | ||
24 | namespace boost{ namespace geometry | |
25 | { | |
26 | ||
27 | ||
28 | // Specialize for Boost.Geometry's coordinate cast | |
29 | // (from string to coordinate type) | |
30 | namespace detail | |
31 | { | |
32 | ||
33 | template <typename T> | |
34 | struct coordinate_cast<rational<T> > | |
35 | { | |
36 | static inline void split_parts(std::string const& source, std::string::size_type p, | |
37 | T& before, T& after, bool& negate, std::string::size_type& len) | |
38 | { | |
39 | std::string before_part = source.substr(0, p); | |
40 | std::string const after_part = source.substr(p + 1); | |
41 | ||
42 | negate = false; | |
43 | ||
44 | if (before_part.size() > 0 && before_part[0] == '-') | |
45 | { | |
46 | negate = true; | |
47 | before_part.erase(0, 1); | |
48 | } | |
49 | before = atol(before_part.c_str()); | |
50 | after = atol(after_part.c_str()); | |
51 | len = after_part.length(); | |
52 | } | |
53 | ||
54 | ||
55 | static inline rational<T> apply(std::string const& source) | |
56 | { | |
57 | T before, after; | |
58 | bool negate; | |
59 | std::string::size_type len; | |
60 | ||
61 | // Note: decimal comma is not (yet) supported, it does (and should) not | |
62 | // occur in a WKT, where points are comma separated. | |
63 | std::string::size_type p = source.find("."); | |
64 | if (p == std::string::npos) | |
65 | { | |
66 | p = source.find("/"); | |
67 | if (p == std::string::npos) | |
68 | { | |
69 | return rational<T>(atol(source.c_str())); | |
70 | } | |
71 | split_parts(source, p, before, after, negate, len); | |
72 | ||
73 | return negate | |
74 | ? -rational<T>(before, after) | |
75 | : rational<T>(before, after) | |
76 | ; | |
77 | ||
78 | } | |
79 | ||
80 | split_parts(source, p, before, after, negate, len); | |
81 | ||
82 | T den = 1; | |
83 | for (std::string::size_type i = 0; i < len; i++) | |
84 | { | |
85 | den *= 10; | |
86 | } | |
87 | ||
88 | return negate | |
89 | ? -rational<T>(before) - rational<T>(after, den) | |
90 | : rational<T>(before) + rational<T>(after, den) | |
91 | ; | |
92 | } | |
93 | }; | |
94 | ||
95 | } // namespace detail | |
96 | ||
97 | // Specialize for Boost.Geometry's select_most_precise | |
98 | template <typename T1, typename T2> | |
99 | struct select_most_precise<boost::rational<T1>, boost::rational<T2> > | |
100 | { | |
101 | typedef typename boost::rational | |
102 | < | |
103 | typename select_most_precise<T1, T2>::type | |
104 | > type; | |
105 | }; | |
106 | ||
107 | template <typename T> | |
108 | struct select_most_precise<boost::rational<T>, double> | |
109 | { | |
110 | typedef typename boost::rational<T> type; | |
111 | }; | |
112 | ||
113 | ||
114 | }} // namespace boost::geometry | |
115 | ||
116 | ||
117 | // Specializes boost::rational to boost::numeric::bounds | |
118 | namespace boost { namespace numeric | |
119 | { | |
120 | ||
121 | template<class T> | |
122 | struct bounds<rational<T> > | |
123 | { | |
124 | static inline rational<T> lowest() | |
125 | { | |
126 | return rational<T>(bounds<T>::lowest(), 1); | |
127 | } | |
128 | static inline rational<T> highest() | |
129 | { | |
130 | return rational<T>(bounds<T>::highest(), 1); | |
131 | } | |
132 | }; | |
133 | ||
134 | }} // namespace boost::numeric | |
135 | ||
136 | ||
137 | // Support for boost::numeric_cast to int and to double (necessary for SVG-mapper) | |
138 | namespace boost { namespace numeric | |
139 | { | |
140 | ||
141 | template | |
142 | < | |
143 | typename T, | |
144 | typename Traits, | |
145 | typename OverflowHandler, | |
146 | typename Float2IntRounder, | |
147 | typename RawConverter, | |
148 | typename UserRangeChecker | |
149 | > | |
150 | struct converter<int, rational<T>, Traits, OverflowHandler, Float2IntRounder, RawConverter, UserRangeChecker> | |
151 | { | |
152 | static inline int convert(rational<T> const& arg) | |
153 | { | |
154 | return int(rational_cast<double>(arg)); | |
155 | } | |
156 | }; | |
157 | ||
158 | template | |
159 | < | |
160 | typename T, | |
161 | typename Traits, | |
162 | typename OverflowHandler, | |
163 | typename Float2IntRounder, | |
164 | typename RawConverter, | |
165 | typename UserRangeChecker | |
166 | > | |
167 | struct converter<double, rational<T>, Traits, OverflowHandler, Float2IntRounder, RawConverter, UserRangeChecker> | |
168 | { | |
169 | static inline double convert(rational<T> const& arg) | |
170 | { | |
171 | return rational_cast<double>(arg); | |
172 | } | |
173 | }; | |
174 | ||
175 | ||
176 | }} | |
177 | ||
178 | ||
179 | #endif // BOOST_GEOMETRY_UTIL_RATIONAL_HPP |