1 | ///////////////////////////////////////////////////////////////////////////////
|
---|
2 | /// \file functional.hpp
|
---|
3 | ///
|
---|
4 | // Copyright 2005 Eric Niebler. Distributed under the Boost
|
---|
5 | // Software License, Version 1.0. (See accompanying file
|
---|
6 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
|
---|
7 |
|
---|
8 | #ifndef BOOST_NUMERIC_FUNCTIONAL_HPP_EAN_08_12_2005
|
---|
9 | #define BOOST_NUMERIC_FUNCTIONAL_HPP_EAN_08_12_2005
|
---|
10 |
|
---|
11 | #include <limits>
|
---|
12 | #include <functional>
|
---|
13 | #include <boost/static_assert.hpp>
|
---|
14 | #include <boost/mpl/if.hpp>
|
---|
15 | #include <boost/mpl/and.hpp>
|
---|
16 | #include <boost/type_traits/remove_const.hpp>
|
---|
17 | #include <boost/type_traits/add_reference.hpp>
|
---|
18 | #include <boost/type_traits/is_empty.hpp>
|
---|
19 | #include <boost/type_traits/is_integral.hpp>
|
---|
20 | #include <boost/type_traits/is_floating_point.hpp>
|
---|
21 | #include <boost/utility/enable_if.hpp>
|
---|
22 | #include <boost/typeof/typeof.hpp>
|
---|
23 | #include <boost/accumulators/accumulators_fwd.hpp>
|
---|
24 | #include <boost/accumulators/numeric/functional_fwd.hpp>
|
---|
25 | #include <boost/accumulators/numeric/detail/function1.hpp>
|
---|
26 | #include <boost/accumulators/numeric/detail/function2.hpp>
|
---|
27 | #include <boost/accumulators/numeric/detail/pod_singleton.hpp>
|
---|
28 |
|
---|
29 | #ifdef BOOST_NUMERIC_FUNCTIONAL_STD_VECTOR_SUPPORT
|
---|
30 | # include <boost/accumulators/numeric/functional/vector.hpp>
|
---|
31 | #endif
|
---|
32 |
|
---|
33 | #ifdef BOOST_NUMERIC_FUNCTIONAL_STD_VALARRAY_SUPPORT
|
---|
34 | # include <boost/accumulators/numeric/functional/valarray.hpp>
|
---|
35 | #endif
|
---|
36 |
|
---|
37 | #ifdef BOOST_NUMERIC_FUNCTIONAL_STD_COMPLEX_SUPPORT
|
---|
38 | # include <boost/accumulators/numeric/functional/complex.hpp>
|
---|
39 | #endif
|
---|
40 |
|
---|
41 | /// INTERNAL ONLY
|
---|
42 | ///
|
---|
43 | #define BOOST_NUMERIC_FUNCTIONAL_HPP_INCLUDED
|
---|
44 |
|
---|
45 | #ifdef BOOST_NUMERIC_FUNCTIONAL_DOXYGEN_INVOKED
|
---|
46 | // Hack to make Doxygen show the inheritance relationships
|
---|
47 | /// INTERNAL ONLY
|
---|
48 | ///
|
---|
49 | namespace std
|
---|
50 | {
|
---|
51 | /// INTERNAL ONLY
|
---|
52 | ///
|
---|
53 | template<class Arg, class Ret> struct unary_function {};
|
---|
54 | /// INTERNAL ONLY
|
---|
55 | ///
|
---|
56 | template<class Left, class Right, class Ret> struct binary_function {};
|
---|
57 | }
|
---|
58 | #endif
|
---|
59 |
|
---|
60 | namespace boost { namespace numeric
|
---|
61 | {
|
---|
62 | namespace functional
|
---|
63 | {
|
---|
64 | /// INTERNAL ONLY
|
---|
65 | ///
|
---|
66 | template<typename A0, typename A1>
|
---|
67 | struct are_integral
|
---|
68 | : mpl::and_<is_integral<A0>, is_integral<A1> >
|
---|
69 | {};
|
---|
70 |
|
---|
71 | template<typename Left, typename Right>
|
---|
72 | struct left_ref
|
---|
73 | {
|
---|
74 | typedef Left &type;
|
---|
75 | };
|
---|
76 |
|
---|
77 | namespace detail
|
---|
78 | {
|
---|
79 | template<typename T>
|
---|
80 | T &lvalue_of();
|
---|
81 | }
|
---|
82 | }
|
---|
83 |
|
---|
84 | // TODO: handle complex weight, valarray, MTL vectors
|
---|
85 |
|
---|
86 | /// INTERNAL ONLY
|
---|
87 | ///
|
---|
88 | #define BOOST_NUMERIC_FUNCTIONAL_DEFINE_UNARY_OP(Name, Op) \
|
---|
89 | namespace functional \
|
---|
90 | { \
|
---|
91 | template<typename Arg> \
|
---|
92 | struct result_of_ ## Name \
|
---|
93 | { \
|
---|
94 | BOOST_TYPEOF_NESTED_TYPEDEF_TPL( \
|
---|
95 | nested \
|
---|
96 | , Op boost::numeric::functional::detail::lvalue_of<Arg>() \
|
---|
97 | ) \
|
---|
98 | typedef typename nested::type type; \
|
---|
99 | }; \
|
---|
100 | template<typename Arg, typename EnableIf> \
|
---|
101 | struct Name ## _base \
|
---|
102 | : std::unary_function< \
|
---|
103 | typename remove_const<Arg>::type \
|
---|
104 | , typename result_of_ ## Name<Arg>::type \
|
---|
105 | > \
|
---|
106 | { \
|
---|
107 | typename result_of_ ## Name<Arg>::type operator ()(Arg &arg) const \
|
---|
108 | { \
|
---|
109 | return Op arg; \
|
---|
110 | } \
|
---|
111 | }; \
|
---|
112 | template<typename Arg, typename ArgTag> \
|
---|
113 | struct Name \
|
---|
114 | : Name ## _base<Arg, void> \
|
---|
115 | {}; \
|
---|
116 | } \
|
---|
117 | namespace op \
|
---|
118 | { \
|
---|
119 | struct Name \
|
---|
120 | : boost::detail::function1<functional::Name<_, functional::tag<_> > > \
|
---|
121 | {}; \
|
---|
122 | } \
|
---|
123 | namespace \
|
---|
124 | { \
|
---|
125 | op::Name const &Name = boost::detail::pod_singleton<op::Name>::instance; \
|
---|
126 | } \
|
---|
127 | /**/
|
---|
128 |
|
---|
129 | /// INTERNAL ONLY
|
---|
130 | ///
|
---|
131 | #define BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(Name, Op, RetType) \
|
---|
132 | namespace functional \
|
---|
133 | { \
|
---|
134 | template<typename Left, typename Right, typename EnableIf> \
|
---|
135 | struct result_of_ ## Name \
|
---|
136 | { \
|
---|
137 | RetType(Left, Op, Right) \
|
---|
138 | }; \
|
---|
139 | template<typename Left, typename Right, typename EnableIf> \
|
---|
140 | struct Name ## _base \
|
---|
141 | : std::binary_function< \
|
---|
142 | typename remove_const<Left>::type \
|
---|
143 | , typename remove_const<Right>::type \
|
---|
144 | , typename result_of_ ## Name<Left, Right>::type \
|
---|
145 | > \
|
---|
146 | { \
|
---|
147 | typename result_of_ ## Name<Left, Right>::type \
|
---|
148 | operator ()(Left &left, Right &right) const \
|
---|
149 | { \
|
---|
150 | return left Op right; \
|
---|
151 | } \
|
---|
152 | }; \
|
---|
153 | template<typename Left, typename Right, typename LeftTag, typename RightTag> \
|
---|
154 | struct Name \
|
---|
155 | : Name ## _base<Left, Right, void> \
|
---|
156 | {}; \
|
---|
157 | } \
|
---|
158 | namespace op \
|
---|
159 | { \
|
---|
160 | struct Name \
|
---|
161 | : boost::detail::function2< \
|
---|
162 | functional::Name<_1, _2, functional::tag<_1>, functional::tag<_2> > \
|
---|
163 | > \
|
---|
164 | {}; \
|
---|
165 | } \
|
---|
166 | namespace \
|
---|
167 | { \
|
---|
168 | op::Name const &Name = boost::detail::pod_singleton<op::Name>::instance; \
|
---|
169 | } \
|
---|
170 | BOOST_ACCUMULATORS_IGNORE_GLOBAL(Name) \
|
---|
171 | /**/
|
---|
172 |
|
---|
173 | /// INTERNAL ONLY
|
---|
174 | ///
|
---|
175 | #define BOOST_NUMERIC_FUNCTIONAL_DEDUCED(Left, Op, Right) \
|
---|
176 | BOOST_TYPEOF_NESTED_TYPEDEF_TPL( \
|
---|
177 | nested \
|
---|
178 | , boost::numeric::functional::detail::lvalue_of<Left>() Op \
|
---|
179 | boost::numeric::functional::detail::lvalue_of<Right>() \
|
---|
180 | ) \
|
---|
181 | typedef typename nested::type type; \
|
---|
182 | /**/
|
---|
183 |
|
---|
184 | /// INTERNAL ONLY
|
---|
185 | ///
|
---|
186 | #define BOOST_NUMERIC_FUNCTIONAL_LEFT(Left, Op, Right) \
|
---|
187 | typedef Left &type; \
|
---|
188 | /**/
|
---|
189 |
|
---|
190 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(plus, +, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
191 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(minus, -, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
192 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(multiplies, *, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
193 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(divides, /, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
194 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(modulus, %, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
195 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(greater, >, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
196 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(greater_equal, >=, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
197 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(less, <, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
198 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(less_equal, <=, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
199 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(equal_to, ==, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
200 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(not_equal_to, !=, BOOST_NUMERIC_FUNCTIONAL_DEDUCED)
|
---|
201 |
|
---|
202 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(assign, =, BOOST_NUMERIC_FUNCTIONAL_LEFT)
|
---|
203 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(plus_assign, +=, BOOST_NUMERIC_FUNCTIONAL_LEFT)
|
---|
204 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(minus_assign, -=, BOOST_NUMERIC_FUNCTIONAL_LEFT)
|
---|
205 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(multiplies_assign, *=, BOOST_NUMERIC_FUNCTIONAL_LEFT)
|
---|
206 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(divides_assign, /=, BOOST_NUMERIC_FUNCTIONAL_LEFT)
|
---|
207 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP(modulus_assign, %=, BOOST_NUMERIC_FUNCTIONAL_LEFT)
|
---|
208 |
|
---|
209 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_UNARY_OP(unary_plus, +)
|
---|
210 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_UNARY_OP(unary_minus, -)
|
---|
211 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_UNARY_OP(complement, ~)
|
---|
212 | BOOST_NUMERIC_FUNCTIONAL_DEFINE_UNARY_OP(logical_not, !)
|
---|
213 |
|
---|
214 | #undef BOOST_NUMERIC_FUNCTIONAL_LEFT
|
---|
215 | #undef BOOST_NUMERIC_FUNCTIONAL_DEDUCED
|
---|
216 | #undef BOOST_NUMERIC_FUNCTIONAL_DEFINE_UNARY_OP
|
---|
217 | #undef BOOST_NUMERIC_FUNCTIONAL_DEFINE_BINARY_OP
|
---|
218 |
|
---|
219 | namespace functional
|
---|
220 | {
|
---|
221 | template<typename Left, typename Right, typename EnableIf>
|
---|
222 | struct min_assign_base
|
---|
223 | : std::binary_function<Left, Right, void>
|
---|
224 | {
|
---|
225 | void operator ()(Left &left, Right &right) const
|
---|
226 | {
|
---|
227 | if(numeric::less(right, left))
|
---|
228 | {
|
---|
229 | left = right;
|
---|
230 | }
|
---|
231 | }
|
---|
232 | };
|
---|
233 |
|
---|
234 | template<typename Left, typename Right, typename EnableIf>
|
---|
235 | struct max_assign_base
|
---|
236 | : std::binary_function<Left, Right, void>
|
---|
237 | {
|
---|
238 | void operator ()(Left &left, Right &right) const
|
---|
239 | {
|
---|
240 | if(numeric::greater(right, left))
|
---|
241 | {
|
---|
242 | left = right;
|
---|
243 | }
|
---|
244 | }
|
---|
245 | };
|
---|
246 |
|
---|
247 | template<typename Left, typename Right, typename EnableIf>
|
---|
248 | struct average_base
|
---|
249 | {
|
---|
250 | // Define the type of the result
|
---|
251 | typedef typename functional::divides<Left, Right>::result_type result_type;
|
---|
252 |
|
---|
253 | result_type operator()(Left & left, Right & right) const
|
---|
254 | {
|
---|
255 | return numeric::divides(numeric::plus(left, right), 2);
|
---|
256 | }
|
---|
257 | };
|
---|
258 |
|
---|
259 | // partial specialization that promotes the arguments to double for
|
---|
260 | // integral division.
|
---|
261 | template<typename Left, typename Right>
|
---|
262 | struct average_base<Left, Right, typename enable_if<are_integral<Left, Right> >::type>
|
---|
263 | : average_base<double const, double const>
|
---|
264 | {};
|
---|
265 |
|
---|
266 | template<typename To, typename From, typename EnableIf>
|
---|
267 | struct promote_base
|
---|
268 | : std::unary_function<From, To>
|
---|
269 | {
|
---|
270 | To operator ()(From &from) const
|
---|
271 | {
|
---|
272 | return from;
|
---|
273 | }
|
---|
274 | };
|
---|
275 |
|
---|
276 | template<typename ToFrom>
|
---|
277 | struct promote_base<ToFrom, ToFrom, void>
|
---|
278 | : std::unary_function<ToFrom, ToFrom>
|
---|
279 | {
|
---|
280 | ToFrom &operator ()(ToFrom &tofrom)
|
---|
281 | {
|
---|
282 | return tofrom;
|
---|
283 | }
|
---|
284 | };
|
---|
285 |
|
---|
286 | template<typename Arg, typename EnableIf>
|
---|
287 | struct as_min_base
|
---|
288 | : std::unary_function<Arg, typename remove_const<Arg>::type>
|
---|
289 | {
|
---|
290 | BOOST_STATIC_ASSERT(std::numeric_limits<typename remove_const<Arg>::type>::is_specialized);
|
---|
291 |
|
---|
292 | typename remove_const<Arg>::type operator ()(Arg &) const
|
---|
293 | {
|
---|
294 | return (std::numeric_limits<typename remove_const<Arg>::type>::min)();
|
---|
295 | }
|
---|
296 | };
|
---|
297 |
|
---|
298 | template<typename Arg>
|
---|
299 | struct as_min_base<Arg, typename enable_if<is_floating_point<Arg> >::type>
|
---|
300 | : std::unary_function<Arg, typename remove_const<Arg>::type>
|
---|
301 | {
|
---|
302 | BOOST_STATIC_ASSERT(std::numeric_limits<typename remove_const<Arg>::type>::is_specialized);
|
---|
303 |
|
---|
304 | typename remove_const<Arg>::type operator ()(Arg &) const
|
---|
305 | {
|
---|
306 | return -(std::numeric_limits<typename remove_const<Arg>::type>::max)();
|
---|
307 | }
|
---|
308 | };
|
---|
309 |
|
---|
310 | template<typename Arg, typename EnableIf>
|
---|
311 | struct as_max_base
|
---|
312 | : std::unary_function<Arg, typename remove_const<Arg>::type>
|
---|
313 | {
|
---|
314 | BOOST_STATIC_ASSERT(std::numeric_limits<typename remove_const<Arg>::type>::is_specialized);
|
---|
315 |
|
---|
316 | typename remove_const<Arg>::type operator ()(Arg &) const
|
---|
317 | {
|
---|
318 | return (std::numeric_limits<typename remove_const<Arg>::type>::max)();
|
---|
319 | }
|
---|
320 | };
|
---|
321 |
|
---|
322 | template<typename Arg, typename EnableIf>
|
---|
323 | struct as_zero_base
|
---|
324 | : std::unary_function<Arg, typename remove_const<Arg>::type>
|
---|
325 | {
|
---|
326 | typename remove_const<Arg>::type operator ()(Arg &) const
|
---|
327 | {
|
---|
328 | return numeric::zero<typename remove_const<Arg>::type>::value;
|
---|
329 | }
|
---|
330 | };
|
---|
331 |
|
---|
332 | template<typename Arg, typename EnableIf>
|
---|
333 | struct as_one_base
|
---|
334 | : std::unary_function<Arg, typename remove_const<Arg>::type>
|
---|
335 | {
|
---|
336 | typename remove_const<Arg>::type operator ()(Arg &) const
|
---|
337 | {
|
---|
338 | return numeric::one<typename remove_const<Arg>::type>::value;
|
---|
339 | }
|
---|
340 | };
|
---|
341 |
|
---|
342 | template<typename To, typename From, typename ToTag, typename FromTag>
|
---|
343 | struct promote
|
---|
344 | : promote_base<To, From, void>
|
---|
345 | {};
|
---|
346 |
|
---|
347 | template<typename Left, typename Right, typename LeftTag, typename RightTag>
|
---|
348 | struct min_assign
|
---|
349 | : min_assign_base<Left, Right, void>
|
---|
350 | {};
|
---|
351 |
|
---|
352 | template<typename Left, typename Right, typename LeftTag, typename RightTag>
|
---|
353 | struct max_assign
|
---|
354 | : max_assign_base<Left, Right, void>
|
---|
355 | {};
|
---|
356 |
|
---|
357 | template<typename Left, typename Right, typename LeftTag, typename RightTag>
|
---|
358 | struct average
|
---|
359 | : average_base<Left, Right, void>
|
---|
360 | {};
|
---|
361 |
|
---|
362 | template<typename Arg, typename Tag>
|
---|
363 | struct as_min
|
---|
364 | : as_min_base<Arg, void>
|
---|
365 | {};
|
---|
366 |
|
---|
367 | template<typename Arg, typename Tag>
|
---|
368 | struct as_max
|
---|
369 | : as_max_base<Arg, void>
|
---|
370 | {};
|
---|
371 |
|
---|
372 | template<typename Arg, typename Tag>
|
---|
373 | struct as_zero
|
---|
374 | : as_zero_base<Arg, void>
|
---|
375 | {};
|
---|
376 |
|
---|
377 | template<typename Arg, typename Tag>
|
---|
378 | struct as_one
|
---|
379 | : as_one_base<Arg, void>
|
---|
380 | {};
|
---|
381 | }
|
---|
382 |
|
---|
383 | namespace op
|
---|
384 | {
|
---|
385 | template<typename To>
|
---|
386 | struct promote
|
---|
387 | : boost::detail::function1<functional::promote<To, _, typename functional::tag<To>::type, functional::tag<_> > >
|
---|
388 | {};
|
---|
389 |
|
---|
390 | struct min_assign
|
---|
391 | : boost::detail::function2<functional::min_assign<_1, _2, functional::tag<_1>, functional::tag<_2> > >
|
---|
392 | {};
|
---|
393 |
|
---|
394 | struct max_assign
|
---|
395 | : boost::detail::function2<functional::max_assign<_1, _2, functional::tag<_1>, functional::tag<_2> > >
|
---|
396 | {};
|
---|
397 |
|
---|
398 | struct average
|
---|
399 | : boost::detail::function2<functional::average<_1, _2, functional::tag<_1>, functional::tag<_2> > >
|
---|
400 | {};
|
---|
401 |
|
---|
402 | struct as_min
|
---|
403 | : boost::detail::function1<functional::as_min<_, functional::tag<_> > >
|
---|
404 | {};
|
---|
405 |
|
---|
406 | struct as_max
|
---|
407 | : boost::detail::function1<functional::as_max<_, functional::tag<_> > >
|
---|
408 | {};
|
---|
409 |
|
---|
410 | struct as_zero
|
---|
411 | : boost::detail::function1<functional::as_zero<_, functional::tag<_> > >
|
---|
412 | {};
|
---|
413 |
|
---|
414 | struct as_one
|
---|
415 | : boost::detail::function1<functional::as_one<_, functional::tag<_> > >
|
---|
416 | {};
|
---|
417 | }
|
---|
418 |
|
---|
419 | namespace
|
---|
420 | {
|
---|
421 | op::min_assign const &min_assign = boost::detail::pod_singleton<op::min_assign>::instance;
|
---|
422 | op::max_assign const &max_assign = boost::detail::pod_singleton<op::max_assign>::instance;
|
---|
423 | op::average const &average = boost::detail::pod_singleton<op::average>::instance;
|
---|
424 | op::as_min const &as_min = boost::detail::pod_singleton<op::as_min>::instance;
|
---|
425 | op::as_max const &as_max = boost::detail::pod_singleton<op::as_max>::instance;
|
---|
426 | op::as_zero const &as_zero = boost::detail::pod_singleton<op::as_zero>::instance;
|
---|
427 | op::as_one const &as_one = boost::detail::pod_singleton<op::as_one>::instance;
|
---|
428 |
|
---|
429 | BOOST_ACCUMULATORS_IGNORE_GLOBAL(min_assign)
|
---|
430 | BOOST_ACCUMULATORS_IGNORE_GLOBAL(max_assign)
|
---|
431 | BOOST_ACCUMULATORS_IGNORE_GLOBAL(average)
|
---|
432 | BOOST_ACCUMULATORS_IGNORE_GLOBAL(as_min)
|
---|
433 | BOOST_ACCUMULATORS_IGNORE_GLOBAL(as_max)
|
---|
434 | BOOST_ACCUMULATORS_IGNORE_GLOBAL(as_zero)
|
---|
435 | BOOST_ACCUMULATORS_IGNORE_GLOBAL(as_one)
|
---|
436 | }
|
---|
437 |
|
---|
438 | ///////////////////////////////////////////////////////////////////////////////
|
---|
439 | // promote
|
---|
440 | template<typename To, typename From>
|
---|
441 | typename lazy_disable_if<is_const<From>, mpl::if_<is_same<To, From>, To &, To> >::type
|
---|
442 | promote(From &from)
|
---|
443 | {
|
---|
444 | return functional::promote<To, From>()(from);
|
---|
445 | }
|
---|
446 |
|
---|
447 | template<typename To, typename From>
|
---|
448 | typename mpl::if_<is_same<To const, From const>, To const &, To const>::type
|
---|
449 | promote(From const &from)
|
---|
450 | {
|
---|
451 | return functional::promote<To const, From const>()(from);
|
---|
452 | }
|
---|
453 |
|
---|
454 | template<typename T>
|
---|
455 | struct default_
|
---|
456 | {
|
---|
457 | typedef default_ type;
|
---|
458 | typedef T value_type;
|
---|
459 | static T const value;
|
---|
460 |
|
---|
461 | operator T const & () const
|
---|
462 | {
|
---|
463 | return default_::value;
|
---|
464 | }
|
---|
465 | };
|
---|
466 |
|
---|
467 | template<typename T>
|
---|
468 | T const default_<T>::value = T();
|
---|
469 |
|
---|
470 | template<typename T>
|
---|
471 | struct one
|
---|
472 | {
|
---|
473 | typedef one type;
|
---|
474 | typedef T value_type;
|
---|
475 | static T const value;
|
---|
476 |
|
---|
477 | operator T const & () const
|
---|
478 | {
|
---|
479 | return one::value;
|
---|
480 | }
|
---|
481 | };
|
---|
482 |
|
---|
483 | template<typename T>
|
---|
484 | T const one<T>::value = T(1);
|
---|
485 |
|
---|
486 | template<typename T>
|
---|
487 | struct zero
|
---|
488 | {
|
---|
489 | typedef zero type;
|
---|
490 | typedef T value_type;
|
---|
491 | static T const value;
|
---|
492 |
|
---|
493 | operator T const & () const
|
---|
494 | {
|
---|
495 | return zero::value;
|
---|
496 | }
|
---|
497 | };
|
---|
498 |
|
---|
499 | template<typename T>
|
---|
500 | T const zero<T>::value = T();
|
---|
501 |
|
---|
502 | template<typename T>
|
---|
503 | struct one_or_default
|
---|
504 | : mpl::if_<is_empty<T>, default_<T>, one<T> >::type
|
---|
505 | {};
|
---|
506 |
|
---|
507 | template<typename T>
|
---|
508 | struct zero_or_default
|
---|
509 | : mpl::if_<is_empty<T>, default_<T>, zero<T> >::type
|
---|
510 | {};
|
---|
511 |
|
---|
512 | }} // namespace boost::numeric
|
---|
513 |
|
---|
514 | #endif
|
---|