]>
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_STATIC_RATIONAL_HPP | |
12 | #define BOOST_UNITS_STATIC_RATIONAL_HPP | |
13 | ||
14 | #include <boost/integer/common_factor_ct.hpp> | |
15 | #include <boost/mpl/less.hpp> | |
16 | #include <boost/mpl/arithmetic.hpp> | |
17 | ||
18 | #ifdef __BORLANDC__ | |
19 | #include <boost/mpl/eval_if.hpp> | |
20 | #include <boost/mpl/integral_c.hpp> | |
21 | #include <boost/mpl/identity.hpp> | |
22 | #endif | |
23 | ||
24 | #include <boost/units/config.hpp> | |
25 | #include <boost/units/operators.hpp> | |
26 | ||
27 | /// \file | |
28 | /// \brief Compile-time rational numbers and operators. | |
29 | ||
30 | namespace boost { | |
31 | ||
32 | namespace units { | |
33 | ||
34 | namespace detail { | |
35 | ||
36 | struct static_rational_tag {}; | |
37 | ||
38 | } | |
39 | ||
40 | typedef long integer_type; | |
41 | ||
42 | /// Compile time absolute value. | |
43 | template<integer_type Value> | |
44 | struct static_abs | |
45 | { | |
46 | BOOST_STATIC_CONSTANT(integer_type,value = Value < 0 ? -Value : Value); | |
47 | }; | |
48 | ||
49 | // Compile time rational number. | |
50 | /** | |
51 | This is an implementation of a compile time rational number, where @c static_rational<N,D> represents | |
52 | a rational number with numerator @c N and denominator @c D. Because of the potential for ambiguity arising | |
53 | from multiple equivalent values of @c static_rational (e.g. @c static_rational<6,2>==static_rational<3>), | |
54 | static rationals should always be accessed through @c static_rational<N,D>::type. Template specialization | |
55 | prevents instantiation of zero denominators (i.e. @c static_rational<N,0>). The following compile-time | |
56 | arithmetic operators are provided for static_rational variables only (no operators are defined between | |
57 | long and static_rational): | |
58 | - @c mpl::negate | |
59 | - @c mpl::plus | |
60 | - @c mpl::minus | |
61 | - @c mpl::times | |
62 | - @c mpl::divides | |
63 | ||
64 | Neither @c static_power nor @c static_root are defined for @c static_rational. This is because template types | |
65 | may not be floating point values, while powers and roots of rational numbers can produce floating point | |
66 | values. | |
67 | */ | |
68 | #ifdef __BORLANDC__ | |
69 | ||
70 | template<integer_type X> | |
71 | struct make_integral_c { | |
72 | typedef boost::mpl::integral_c<integer_type, X> type; | |
73 | }; | |
74 | ||
75 | template<integer_type N,integer_type D = 1> | |
76 | class static_rational | |
77 | { | |
78 | public: | |
79 | ||
80 | typedef static_rational this_type; | |
81 | ||
82 | typedef boost::mpl::integral_c<integer_type, N> N_type; | |
83 | typedef boost::mpl::integral_c<integer_type, D> D_type; | |
84 | ||
85 | typedef typename make_integral_c< | |
86 | (::boost::integer::static_gcd< | |
87 | ::boost::units::static_abs<N>::value, | |
88 | ::boost::units::static_abs<D>::value | |
89 | >::value)>::type gcd_type; | |
90 | typedef typename boost::mpl::eval_if< | |
91 | boost::mpl::less< | |
92 | D_type, | |
93 | boost::mpl::integral_c<integer_type, 0> | |
94 | >, | |
95 | boost::mpl::negate<gcd_type>, | |
96 | gcd_type | |
97 | >::type den_type; | |
98 | ||
99 | public: | |
100 | // for mpl arithmetic support | |
101 | typedef detail::static_rational_tag tag; | |
102 | ||
103 | BOOST_STATIC_CONSTANT(integer_type, Numerator = | |
104 | (::boost::mpl::divides<N_type, den_type>::value)); | |
105 | BOOST_STATIC_CONSTANT(integer_type, Denominator = | |
106 | (::boost::mpl::divides<D_type, den_type>::value)); | |
107 | ||
108 | /// INTERNAL ONLY | |
109 | typedef static_rational<N,D> this_type; | |
110 | ||
111 | /// static_rational<N,D> reduced by GCD | |
112 | typedef static_rational< | |
113 | (::boost::mpl::divides<N_type, den_type>::value), | |
114 | (::boost::mpl::divides<D_type, den_type>::value) | |
115 | > type; | |
116 | ||
117 | static integer_type numerator() { return Numerator; } | |
118 | static integer_type denominator() { return Denominator; } | |
119 | ||
120 | // INTERNAL ONLY | |
121 | static_rational() { } | |
122 | //~static_rational() { } | |
123 | }; | |
124 | #else | |
125 | template<integer_type N,integer_type D = 1> | |
126 | class static_rational | |
127 | { | |
128 | private: | |
129 | ||
130 | static const integer_type nabs = static_abs<N>::value, | |
131 | dabs = static_abs<D>::value; | |
132 | ||
133 | /// greatest common divisor of N and D | |
134 | // need cast to signed because static_gcd returns unsigned long | |
135 | static const integer_type den = | |
136 | static_cast<integer_type>(boost::integer::static_gcd<nabs,dabs>::value) * ((D < 0) ? -1 : 1); | |
137 | ||
138 | public: | |
139 | // for mpl arithmetic support | |
140 | typedef detail::static_rational_tag tag; | |
141 | ||
142 | static const integer_type Numerator = N/den, | |
143 | Denominator = D/den; | |
144 | ||
145 | /// INTERNAL ONLY | |
146 | typedef static_rational<N,D> this_type; | |
147 | ||
148 | /// static_rational<N,D> reduced by GCD | |
149 | typedef static_rational<Numerator,Denominator> type; | |
150 | ||
151 | static integer_type numerator() { return Numerator; } | |
152 | static integer_type denominator() { return Denominator; } | |
153 | ||
154 | // INTERNAL ONLY | |
155 | static_rational() { } | |
156 | //~static_rational() { } | |
157 | }; | |
158 | #endif | |
159 | ||
160 | } | |
161 | ||
162 | } | |
163 | ||
164 | #if BOOST_UNITS_HAS_BOOST_TYPEOF | |
165 | ||
166 | #include BOOST_TYPEOF_INCREMENT_REGISTRATION_GROUP() | |
167 | ||
168 | BOOST_TYPEOF_REGISTER_TEMPLATE(boost::units::static_rational, (long)(long)) | |
169 | ||
170 | #endif | |
171 | ||
172 | namespace boost { | |
173 | ||
174 | namespace units { | |
175 | ||
176 | // prohibit zero denominator | |
177 | template<integer_type N> class static_rational<N,0>; | |
178 | ||
179 | /// get decimal value of @c static_rational | |
180 | template<class T,integer_type N,integer_type D> | |
181 | inline typename divide_typeof_helper<T,T>::type | |
182 | value(const static_rational<N,D>&) | |
183 | { | |
184 | return T(N)/T(D); | |
185 | } | |
186 | ||
187 | } // namespace units | |
188 | ||
189 | #ifndef BOOST_UNITS_DOXYGEN | |
190 | ||
191 | namespace mpl { | |
192 | ||
193 | #ifdef __BORLANDC__ | |
194 | ||
195 | template<> | |
196 | struct plus_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
197 | { | |
198 | template<class T0, class T1> | |
199 | struct apply { | |
200 | typedef typename boost::units::static_rational< | |
201 | ::boost::mpl::plus< | |
202 | boost::mpl::times<typename T0::N_type, typename T1::D_type>, | |
203 | boost::mpl::times<typename T1::N_type, typename T0::D_type> | |
204 | >::value, | |
205 | ::boost::mpl::times<typename T0::D_type, typename T1::D_type>::value | |
206 | >::type type; | |
207 | }; | |
208 | }; | |
209 | ||
210 | template<> | |
211 | struct minus_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
212 | { | |
213 | template<class T0, class T1> | |
214 | struct apply { | |
215 | typedef typename boost::units::static_rational< | |
216 | ::boost::mpl::minus< | |
217 | boost::mpl::times<typename T0::N_type, typename T1::D_type>, | |
218 | boost::mpl::times<typename T1::N_type, typename T0::D_type> | |
219 | >::value, | |
220 | ::boost::mpl::times<typename T0::D_type, typename T1::D_type>::value | |
221 | >::type type; | |
222 | }; | |
223 | }; | |
224 | ||
225 | template<> | |
226 | struct times_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
227 | { | |
228 | template<class T0, class T1> | |
229 | struct apply { | |
230 | typedef typename boost::units::static_rational< | |
231 | ::boost::mpl::times<typename T0::N_type, typename T1::N_type>::value, | |
232 | ::boost::mpl::times<typename T0::D_type, typename T1::D_type>::value | |
233 | >::type type; | |
234 | }; | |
235 | }; | |
236 | ||
237 | template<> | |
238 | struct divides_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
239 | { | |
240 | template<class T0, class T1> | |
241 | struct apply { | |
242 | typedef typename boost::units::static_rational< | |
243 | ::boost::mpl::times<typename T0::N_type, typename T1::D_type>::value, | |
244 | ::boost::mpl::times<typename T0::D_type, typename T1::N_type>::value | |
245 | >::type type; | |
246 | }; | |
247 | }; | |
248 | ||
249 | template<> | |
250 | struct negate_impl<boost::units::detail::static_rational_tag> | |
251 | { | |
252 | template<class T0> | |
253 | struct apply { | |
254 | typedef typename boost::units::static_rational< | |
255 | ::boost::mpl::negate<typename T0::N_type>::value, | |
256 | ::boost::mpl::identity<T0>::type::Denominator | |
257 | >::type type; | |
258 | }; | |
259 | }; | |
260 | ||
261 | template<> | |
262 | struct less_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
263 | { | |
264 | template<class T0, class T1> | |
265 | struct apply | |
266 | { | |
267 | typedef mpl::bool_<((mpl::minus<T0, T1>::type::Numerator) < 0)> type; | |
268 | }; | |
269 | }; | |
270 | ||
271 | #else | |
272 | ||
273 | template<> | |
274 | struct plus_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
275 | { | |
276 | template<class T0, class T1> | |
277 | struct apply { | |
278 | typedef typename boost::units::static_rational< | |
279 | T0::Numerator*T1::Denominator+T1::Numerator*T0::Denominator, | |
280 | T0::Denominator*T1::Denominator | |
281 | >::type type; | |
282 | }; | |
283 | }; | |
284 | ||
285 | template<> | |
286 | struct minus_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
287 | { | |
288 | template<class T0, class T1> | |
289 | struct apply { | |
290 | typedef typename boost::units::static_rational< | |
291 | T0::Numerator*T1::Denominator-T1::Numerator*T0::Denominator, | |
292 | T0::Denominator*T1::Denominator | |
293 | >::type type; | |
294 | }; | |
295 | }; | |
296 | ||
297 | template<> | |
298 | struct times_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
299 | { | |
300 | template<class T0, class T1> | |
301 | struct apply { | |
302 | typedef typename boost::units::static_rational< | |
303 | T0::Numerator*T1::Numerator, | |
304 | T0::Denominator*T1::Denominator | |
305 | >::type type; | |
306 | }; | |
307 | }; | |
308 | ||
309 | template<> | |
310 | struct divides_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
311 | { | |
312 | template<class T0, class T1> | |
313 | struct apply { | |
314 | typedef typename boost::units::static_rational< | |
315 | T0::Numerator*T1::Denominator, | |
316 | T0::Denominator*T1::Numerator | |
317 | >::type type; | |
318 | }; | |
319 | }; | |
320 | ||
321 | template<> | |
322 | struct negate_impl<boost::units::detail::static_rational_tag> | |
323 | { | |
324 | template<class T0> | |
325 | struct apply { | |
326 | typedef typename boost::units::static_rational<-T0::Numerator,T0::Denominator>::type type; | |
327 | }; | |
328 | }; | |
329 | ||
330 | template<> | |
331 | struct less_impl<boost::units::detail::static_rational_tag, boost::units::detail::static_rational_tag> | |
332 | { | |
333 | template<class T0, class T1> | |
334 | struct apply | |
335 | { | |
336 | typedef mpl::bool_<((mpl::minus<T0, T1>::type::Numerator) < 0)> type; | |
337 | }; | |
338 | }; | |
339 | ||
340 | #endif | |
341 | ||
342 | ||
343 | } | |
344 | ||
345 | #endif | |
346 | ||
347 | } // namespace boost | |
348 | ||
349 | #endif // BOOST_UNITS_STATIC_RATIONAL_HPP |