1 | #ifndef _DATE_TIME_INT_ADAPTER_HPP__ |
2 | #define _DATE_TIME_INT_ADAPTER_HPP__ |
3 | |
4 | /* Copyright (c) 2002,2003 CrystalClear Software, Inc. |
5 | * Use, modification and distribution is subject to the |
6 | * Boost Software License, Version 1.0. (See accompanying |
7 | * file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt) |
8 | * Author: Jeff Garland, Bart Garst |
9 | * $Date$ |
10 | */ |
11 | |
12 | |
13 | #include "boost/config.hpp" |
14 | #include "boost/limits.hpp" //work around compilers without limits |
15 | #include "boost/date_time/special_defs.hpp" |
16 | #include "boost/date_time/locale_config.hpp" |
17 | #ifndef BOOST_DATE_TIME_NO_LOCALE |
18 | # include <ostream> |
19 | #endif |
20 | |
21 | namespace boost { |
22 | namespace date_time { |
23 | |
24 | |
25 | //! Adapter to create integer types with +-infinity, and not a value |
26 | /*! This class is used internally in counted date/time representations. |
27 | * It adds the floating point like features of infinities and |
28 | * not a number. It also provides mathmatical operations with |
29 | * consideration to special values following these rules: |
30 | *@code |
31 | * +infinity - infinity == Not A Number (NAN) |
32 | * infinity * non-zero == infinity |
33 | * infinity * zero == NAN |
34 | * +infinity * -integer == -infinity |
35 | * infinity / infinity == NAN |
36 | * infinity * infinity == infinity |
37 | *@endcode |
38 | */ |
39 | template<typename int_type_> |
40 | class int_adapter { |
41 | public: |
42 | typedef int_type_ int_type; |
43 | int_adapter(int_type v) : |
44 | value_(v) |
45 | {} |
46 | static bool has_infinity() |
47 | { |
48 | return true; |
49 | } |
50 | static const int_adapter pos_infinity() |
51 | { |
52 | return (::std::numeric_limits<int_type>::max)(); |
53 | } |
54 | static const int_adapter neg_infinity() |
55 | { |
56 | return (::std::numeric_limits<int_type>::min)(); |
57 | } |
58 | static const int_adapter not_a_number() |
59 | { |
60 | return (::std::numeric_limits<int_type>::max)()-1; |
61 | } |
62 | static int_adapter max BOOST_PREVENT_MACRO_SUBSTITUTION () |
63 | { |
64 | return (::std::numeric_limits<int_type>::max)()-2; |
65 | } |
66 | static int_adapter min BOOST_PREVENT_MACRO_SUBSTITUTION () |
67 | { |
68 | return (::std::numeric_limits<int_type>::min)()+1; |
69 | } |
70 | static int_adapter from_special(special_values sv) |
71 | { |
72 | switch (sv) { |
73 | case not_a_date_time: return not_a_number(); |
74 | case neg_infin: return neg_infinity(); |
75 | case pos_infin: return pos_infinity(); |
76 | case max_date_time: return (max)(); |
77 | case min_date_time: return (min)(); |
78 | default: return not_a_number(); |
79 | } |
80 | } |
81 | static bool is_inf(int_type v) |
82 | { |
83 | return (v == neg_infinity().as_number() || |
84 | v == pos_infinity().as_number()); |
85 | } |
86 | static bool is_neg_inf(int_type v) |
87 | { |
88 | return (v == neg_infinity().as_number()); |
89 | } |
90 | static bool is_pos_inf(int_type v) |
91 | { |
92 | return (v == pos_infinity().as_number()); |
93 | } |
94 | static bool is_not_a_number(int_type v) |
95 | { |
96 | return (v == not_a_number().as_number()); |
97 | } |
98 | //! Returns either special value type or is_not_special |
99 | static special_values to_special(int_type v) |
100 | { |
101 | if (is_not_a_number(v)) return not_a_date_time; |
102 | if (is_neg_inf(v)) return neg_infin; |
103 | if (is_pos_inf(v)) return pos_infin; |
104 | return not_special; |
105 | } |
106 | |
107 | //-3 leaves room for representations of infinity and not a date |
108 | static int_type maxcount() |
109 | { |
110 | return (::std::numeric_limits<int_type>::max)()-3; |
111 | } |
112 | bool is_infinity() const |
113 | { |
114 | return (value_ == neg_infinity().as_number() || |
115 | value_ == pos_infinity().as_number()); |
116 | } |
117 | bool is_pos_infinity()const |
118 | { |
119 | return(value_ == pos_infinity().as_number()); |
120 | } |
121 | bool is_neg_infinity()const |
122 | { |
123 | return(value_ == neg_infinity().as_number()); |
124 | } |
125 | bool is_nan() const |
126 | { |
127 | return (value_ == not_a_number().as_number()); |
128 | } |
129 | bool is_special() const |
130 | { |
131 | return(is_infinity() || is_nan()); |
132 | } |
133 | bool operator==(const int_adapter& rhs) const |
134 | { |
135 | return (compare(rhs) == 0); |
136 | } |
137 | bool operator==(const int& rhs) const |
138 | { |
139 | // quiets compiler warnings |
140 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
141 | if(!is_signed) |
142 | { |
143 | if(is_neg_inf(v: value_) && rhs == 0) |
144 | { |
145 | return false; |
146 | } |
147 | } |
148 | return (compare(rhs) == 0); |
149 | } |
150 | bool operator!=(const int_adapter& rhs) const |
151 | { |
152 | return (compare(rhs) != 0); |
153 | } |
154 | bool operator!=(const int& rhs) const |
155 | { |
156 | // quiets compiler warnings |
157 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
158 | if(!is_signed) |
159 | { |
160 | if(is_neg_inf(v: value_) && rhs == 0) |
161 | { |
162 | return true; |
163 | } |
164 | } |
165 | return (compare(rhs) != 0); |
166 | } |
167 | bool operator<(const int_adapter& rhs) const |
168 | { |
169 | return (compare(rhs) == -1); |
170 | } |
171 | bool operator<(const int& rhs) const |
172 | { |
173 | // quiets compiler warnings |
174 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
175 | if(!is_signed) |
176 | { |
177 | if(is_neg_inf(v: value_) && rhs == 0) |
178 | { |
179 | return true; |
180 | } |
181 | } |
182 | return (compare(rhs) == -1); |
183 | } |
184 | bool operator>(const int_adapter& rhs) const |
185 | { |
186 | return (compare(rhs) == 1); |
187 | } |
188 | int_type as_number() const |
189 | { |
190 | return value_; |
191 | } |
192 | //! Returns either special value type or is_not_special |
193 | special_values as_special() const |
194 | { |
195 | return int_adapter::to_special(v: value_); |
196 | } |
197 | //creates nasty ambiguities |
198 | // operator int_type() const |
199 | // { |
200 | // return value_; |
201 | // } |
202 | |
203 | /*! Operator allows for adding dissimilar int_adapter types. |
204 | * The return type will match that of the the calling object's type */ |
205 | template<class rhs_type> |
206 | inline |
207 | int_adapter operator+(const int_adapter<rhs_type>& rhs) const |
208 | { |
209 | if(is_special() || rhs.is_special()) |
210 | { |
211 | if (is_nan() || rhs.is_nan()) |
212 | { |
213 | return int_adapter::not_a_number(); |
214 | } |
215 | if((is_pos_inf(v: value_) && rhs.is_neg_inf(rhs.as_number())) || |
216 | (is_neg_inf(v: value_) && rhs.is_pos_inf(rhs.as_number())) ) |
217 | { |
218 | return int_adapter::not_a_number(); |
219 | } |
220 | if (is_infinity()) |
221 | { |
222 | return *this; |
223 | } |
224 | if (rhs.is_pos_inf(rhs.as_number())) |
225 | { |
226 | return int_adapter::pos_infinity(); |
227 | } |
228 | if (rhs.is_neg_inf(rhs.as_number())) |
229 | { |
230 | return int_adapter::neg_infinity(); |
231 | } |
232 | } |
233 | return int_adapter<int_type>(value_ + static_cast<int_type>(rhs.as_number())); |
234 | } |
235 | |
236 | int_adapter operator+(const int_type rhs) const |
237 | { |
238 | if(is_special()) |
239 | { |
240 | if (is_nan()) |
241 | { |
242 | return int_adapter<int_type>(not_a_number()); |
243 | } |
244 | if (is_infinity()) |
245 | { |
246 | return *this; |
247 | } |
248 | } |
249 | return int_adapter<int_type>(value_ + rhs); |
250 | } |
251 | |
252 | /*! Operator allows for subtracting dissimilar int_adapter types. |
253 | * The return type will match that of the the calling object's type */ |
254 | template<class rhs_type> |
255 | inline |
256 | int_adapter operator-(const int_adapter<rhs_type>& rhs)const |
257 | { |
258 | if(is_special() || rhs.is_special()) |
259 | { |
260 | if (is_nan() || rhs.is_nan()) |
261 | { |
262 | return int_adapter::not_a_number(); |
263 | } |
264 | if((is_pos_inf(v: value_) && rhs.is_pos_inf(rhs.as_number())) || |
265 | (is_neg_inf(v: value_) && rhs.is_neg_inf(rhs.as_number())) ) |
266 | { |
267 | return int_adapter::not_a_number(); |
268 | } |
269 | if (is_infinity()) |
270 | { |
271 | return *this; |
272 | } |
273 | if (rhs.is_pos_inf(rhs.as_number())) |
274 | { |
275 | return int_adapter::neg_infinity(); |
276 | } |
277 | if (rhs.is_neg_inf(rhs.as_number())) |
278 | { |
279 | return int_adapter::pos_infinity(); |
280 | } |
281 | } |
282 | return int_adapter<int_type>(value_ - static_cast<int_type>(rhs.as_number())); |
283 | } |
284 | int_adapter operator-(const int_type rhs) const |
285 | { |
286 | if(is_special()) |
287 | { |
288 | if (is_nan()) |
289 | { |
290 | return int_adapter<int_type>(not_a_number()); |
291 | } |
292 | if (is_infinity()) |
293 | { |
294 | return *this; |
295 | } |
296 | } |
297 | return int_adapter<int_type>(value_ - rhs); |
298 | } |
299 | |
300 | // should templatize this to be consistant with op +- |
301 | int_adapter operator*(const int_adapter& rhs)const |
302 | { |
303 | if(this->is_special() || rhs.is_special()) |
304 | { |
305 | return mult_div_specials(rhs); |
306 | } |
307 | return int_adapter<int_type>(value_ * rhs.value_); |
308 | } |
309 | /*! Provided for cases when automatic conversion from |
310 | * 'int' to 'int_adapter' causes incorrect results. */ |
311 | int_adapter operator*(const int rhs) const |
312 | { |
313 | if(is_special()) |
314 | { |
315 | return mult_div_specials(rhs); |
316 | } |
317 | return int_adapter<int_type>(value_ * rhs); |
318 | } |
319 | |
320 | // should templatize this to be consistant with op +- |
321 | int_adapter operator/(const int_adapter& rhs)const |
322 | { |
323 | if(this->is_special() || rhs.is_special()) |
324 | { |
325 | if(is_infinity() && rhs.is_infinity()) |
326 | { |
327 | return int_adapter<int_type>(not_a_number()); |
328 | } |
329 | if(rhs != 0) |
330 | { |
331 | return mult_div_specials(rhs); |
332 | } |
333 | else { // let divide by zero blow itself up |
334 | return int_adapter<int_type>(value_ / rhs.value_); |
335 | } |
336 | } |
337 | return int_adapter<int_type>(value_ / rhs.value_); |
338 | } |
339 | /*! Provided for cases when automatic conversion from |
340 | * 'int' to 'int_adapter' causes incorrect results. */ |
341 | int_adapter operator/(const int rhs) const |
342 | { |
343 | if(is_special() && rhs != 0) |
344 | { |
345 | return mult_div_specials(rhs); |
346 | } |
347 | return int_adapter<int_type>(value_ / rhs); |
348 | } |
349 | |
350 | // should templatize this to be consistant with op +- |
351 | int_adapter operator%(const int_adapter& rhs)const |
352 | { |
353 | if(this->is_special() || rhs.is_special()) |
354 | { |
355 | if(is_infinity() && rhs.is_infinity()) |
356 | { |
357 | return int_adapter<int_type>(not_a_number()); |
358 | } |
359 | if(rhs != 0) |
360 | { |
361 | return mult_div_specials(rhs); |
362 | } |
363 | else { // let divide by zero blow itself up |
364 | return int_adapter<int_type>(value_ % rhs.value_); |
365 | } |
366 | } |
367 | return int_adapter<int_type>(value_ % rhs.value_); |
368 | } |
369 | /*! Provided for cases when automatic conversion from |
370 | * 'int' to 'int_adapter' causes incorrect results. */ |
371 | int_adapter operator%(const int rhs) const |
372 | { |
373 | if(is_special() && rhs != 0) |
374 | { |
375 | return mult_div_specials(rhs); |
376 | } |
377 | return int_adapter<int_type>(value_ % rhs); |
378 | } |
379 | private: |
380 | int_type value_; |
381 | |
382 | //! returns -1, 0, 1, or 2 if 'this' is <, ==, >, or 'nan comparison' rhs |
383 | int compare(const int_adapter& rhs)const |
384 | { |
385 | if(this->is_special() || rhs.is_special()) |
386 | { |
387 | if(this->is_nan() || rhs.is_nan()) { |
388 | if(this->is_nan() && rhs.is_nan()) { |
389 | return 0; // equal |
390 | } |
391 | else { |
392 | return 2; // nan |
393 | } |
394 | } |
395 | if((is_neg_inf(v: value_) && !is_neg_inf(v: rhs.value_)) || |
396 | (is_pos_inf(v: rhs.value_) && !is_pos_inf(v: value_)) ) |
397 | { |
398 | return -1; // less than |
399 | } |
400 | if((is_pos_inf(v: value_) && !is_pos_inf(v: rhs.value_)) || |
401 | (is_neg_inf(v: rhs.value_) && !is_neg_inf(v: value_)) ) { |
402 | return 1; // greater than |
403 | } |
404 | } |
405 | if(value_ < rhs.value_) return -1; |
406 | if(value_ > rhs.value_) return 1; |
407 | // implied-> if(value_ == rhs.value_) |
408 | return 0; |
409 | } |
410 | /* When multiplying and dividing with at least 1 special value |
411 | * very simmilar rules apply. In those cases where the rules |
412 | * are different, they are handled in the respective operator |
413 | * function. */ |
414 | //! Assumes at least 'this' or 'rhs' is a special value |
415 | int_adapter mult_div_specials(const int_adapter& rhs)const |
416 | { |
417 | int min_value; |
418 | // quiets compiler warnings |
419 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
420 | if(is_signed) { |
421 | min_value = 0; |
422 | } |
423 | else { |
424 | min_value = 1;// there is no zero with unsigned |
425 | } |
426 | if(this->is_nan() || rhs.is_nan()) { |
427 | return int_adapter<int_type>(not_a_number()); |
428 | } |
429 | if((*this > 0 && rhs > 0) || (*this < min_value && rhs < min_value)) { |
430 | return int_adapter<int_type>(pos_infinity()); |
431 | } |
432 | if((*this > 0 && rhs < min_value) || (*this < min_value && rhs > 0)) { |
433 | return int_adapter<int_type>(neg_infinity()); |
434 | } |
435 | //implied -> if(this->value_ == 0 || rhs.value_ == 0) |
436 | return int_adapter<int_type>(not_a_number()); |
437 | } |
438 | /* Overloaded function necessary because of special |
439 | * situation where int_adapter is instantiated with |
440 | * 'unsigned' and func is called with negative int. |
441 | * It would produce incorrect results since 'unsigned' |
442 | * wraps around when initialized with a negative value */ |
443 | //! Assumes 'this' is a special value |
444 | int_adapter mult_div_specials(const int& rhs) const |
445 | { |
446 | int min_value; |
447 | // quiets compiler warnings |
448 | bool is_signed = std::numeric_limits<int_type>::is_signed; |
449 | if(is_signed) { |
450 | min_value = 0; |
451 | } |
452 | else { |
453 | min_value = 1;// there is no zero with unsigned |
454 | } |
455 | if(this->is_nan()) { |
456 | return int_adapter<int_type>(not_a_number()); |
457 | } |
458 | if((*this > 0 && rhs > 0) || (*this < min_value && rhs < 0)) { |
459 | return int_adapter<int_type>(pos_infinity()); |
460 | } |
461 | if((*this > 0 && rhs < 0) || (*this < min_value && rhs > 0)) { |
462 | return int_adapter<int_type>(neg_infinity()); |
463 | } |
464 | //implied -> if(this->value_ == 0 || rhs.value_ == 0) |
465 | return int_adapter<int_type>(not_a_number()); |
466 | } |
467 | |
468 | }; |
469 | |
470 | #ifndef BOOST_DATE_TIME_NO_LOCALE |
471 | /*! Expected output is either a numeric representation |
472 | * or a special values representation.<BR> |
473 | * Ex. "12", "+infinity", "not-a-number", etc. */ |
474 | //template<class charT = char, class traits = std::traits<charT>, typename int_type> |
475 | template<class charT, class traits, typename int_type> |
476 | inline |
477 | std::basic_ostream<charT, traits>& |
478 | operator<<(std::basic_ostream<charT, traits>& os, const int_adapter<int_type>& ia) |
479 | { |
480 | if(ia.is_special()) { |
481 | // switch copied from date_names_put.hpp |
482 | switch(ia.as_special()) |
483 | { |
484 | case not_a_date_time: |
485 | os << "not-a-number" ; |
486 | break; |
487 | case pos_infin: |
488 | os << "+infinity" ; |
489 | break; |
490 | case neg_infin: |
491 | os << "-infinity" ; |
492 | break; |
493 | default: |
494 | os << "" ; |
495 | } |
496 | } |
497 | else { |
498 | os << ia.as_number(); |
499 | } |
500 | return os; |
501 | } |
502 | #endif |
503 | |
504 | |
505 | } } //namespace date_time |
506 | |
507 | |
508 | |
509 | #endif |
510 | |