1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
|
<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN"
"../../../tools/boostbook/dtd/boostbook.dtd">
<!-- Copyright (c) 2001-2006 CrystalClear Software, Inc.
Subject to the Boost Software License, Version 1.0.
(See accompanying file LICENSE_1_0.txt or http://www.boost.org/LICENSE_1_0.txt)
-->
<section id="date_time.posix_time.time_period">
<title>Time Period</title>
<link linkend="time_period_intro">Introduction</link> --
<link linkend="time_period_header">Header</link> --
<link linkend="time_period_constr">Construction</link> --
<link linkend="time_period_mutators">Mutators</link> --
<link linkend="time_period_accessors">Accessors</link> --
<link linkend="time_period_to_string">Conversion To String</link> --
<link linkend="time_period_operators">Operators</link>
<anchor id="time_period_intro" />
<bridgehead renderas="sect3">Introduction</bridgehead>
<para>
The class boost::posix_time::time_period provides direct representation for ranges between two times. Periods provide the ability to simplify some types of calculations by simplifying the conditional logic of the program.
</para>
<para>
A period that is created with beginning and end points being equal, or with a duration of zero, is known as a zero length period. Zero length periods are considered invalid (it is perfectly legal to construct an invalid period). For these periods, the <code>last</code> point will always be one unit less that the <code>begin</code> point.
</para>
<para>
The <link linkend="date_time.examples.time_periods">time periods example</link> provides an example of using time periods.
</para>
<anchor id="time_period_header" />
<bridgehead renderas="sect3">Header</bridgehead>
<para>
<programlisting>#include "boost/date_time/posix_time/posix_time.hpp" //include all types plus i/o
or
#include "boost/date_time/posix_time/posix_time_types.hpp" //no i/o just types</programlisting>
</para>
<anchor id="time_period_constr" />
<bridgehead renderas="sect3">Construction</bridgehead>
<para>
<informaltable frame="all">
<tgroup cols="2">
<thead>
<row>
<entry valign="top" morerows="1">Syntax</entry>
<entry>Description</entry>
</row>
<row>
<entry>Example</entry>
</row>
</thead>
<tbody>
<row>
<entry valign="top" morerows="1"><screen>time_period(ptime,
ptime)</screen></entry>
<entry> Create a period as [begin, end). If end is <= begin then the period will be defined as invalid.</entry>
</row>
<row>
<entry><screen>date d(2002,Jan,01);
ptime t(d, seconds(10)); //10 sec after midnight
time_period tp(t, hours(3));</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>time_period(ptime,
time_duration)</screen></entry>
<entry> Create a period as [begin, begin+len) where end would be begin+len. If len is <= zero then the period will be defined as invalid.</entry>
</row>
<row>
<entry><screen>date d(2002,Jan,01);
ptime t1(d, seconds(10)); //10 sec after midnight
ptime t2(d, hours(10)); //10 hours after midnight
time_period tp(t1, t2);</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>time_period(time_period rhs)</screen></entry>
<entry> Copy constructor</entry>
</row>
<row>
<entry><screen>time_period tp1(tp);</screen></entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
<anchor id="time_period_mutators" />
<bridgehead renderas="sect3">Mutators</bridgehead>
<para>
<informaltable frame="all">
<tgroup cols="2">
<thead>
<row>
<entry valign="top" morerows="1">Syntax</entry>
<entry>Description</entry>
</row>
<row>
<entry>Example</entry>
</row>
</thead>
<tbody>
<row>
<entry valign="top" morerows="1"><screen>time_period shift(time_duration)</screen></entry>
<entry>Add duration to both begin and end.</entry>
</row>
<row>
<entry>
<screen>
time_period tp(ptime(date(2005,Jan,1),hours(1)), hours(2));
tp.shift(minutes(5));
// tp == 2005-Jan-01 01:05:00 to 2005-Jan-01 03:05:00
</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>time_period expand(days)</screen></entry>
<entry>Add duration to both begin and end.</entry>
</row>
<row>
<screen>
time_period tp(ptime(date(2005,Jan,1),hours(1)), hours(2));
tp.expand(minutes(5));
// tp == 2005-Jan-01 00:55:00 to 2005-Jan-01 03:05:00
</screen>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
<anchor id="time_period_accessors" />
<bridgehead renderas="sect3">Accessors</bridgehead>
<para>
<informaltable frame="all">
<tgroup cols="2">
<thead>
<row>
<entry valign="top" morerows="1">Syntax</entry>
<entry>Description</entry>
</row>
<row>
<entry>Example</entry>
</row>
</thead>
<tbody>
<row>
<entry valign="top" morerows="1"><screen>ptime begin()</screen></entry>
<entry>Return first time of period.</entry>
</row>
<row>
<entry><screen>date d(2002,Jan,01);
ptime t1(d, seconds(10)); //10 sec after midnight
ptime t2(d, hours(10)); //10 hours after midnight
time_period tp(t1, t2);
tp.begin(); // --> 2002-Jan-01 00:00:10</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>ptime last()</screen></entry>
<entry>Return last time in the period</entry>
</row>
<row>
<entry><screen>date d(2002,Jan,01);
ptime t1(d, seconds(10)); //10 sec after midnight
ptime t2(d, hours(10)); //10 hours after midnight
time_period tp(t1, t2);
tp.last();// --> 2002-Jan-01 09:59:59.999999999</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>ptime end()</screen></entry>
<entry> Return one past the last in period</entry>
</row>
<row>
<entry><screen>date d(2002,Jan,01);
ptime t1(d, seconds(10)); //10 sec after midnight
ptime t2(d, hours(10)); //10 hours after midnight
time_period tp(t1, t2);
tp.last(); // --> 2002-Jan-01 10:00:00</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>time_duration length()</screen></entry>
<entry>Return the length of the time period.</entry>
</row>
<row>
<entry><screen>date d(2002,Jan,01);
ptime t1(d); //midnight
time_period tp(t1, hours(1));
tp.length() --> 1 hour</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>bool is_null()</screen></entry>
<entry>True if period is not well formed. eg: end is less than or equal to begin.</entry>
</row>
<row>
<entry><screen>date d(2002,Jan,01);
ptime t1(d, hours(12)); // noon on Jan 1st
ptime t2(d, hours(9)); // 9am on Jan 1st
time_period tp(t1, t2);
tp.is_null(); // true</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>bool contains(ptime)</screen></entry>
<entry>True if ptime is within the period. Zero length periods cannot contain any points.</entry>
</row>
<row>
<entry><screen>date d(2002,Jan,01);
ptime t1(d, seconds(10)); //10 sec after midnight
ptime t2(d, hours(10)); //10 hours after midnight
ptime t3(d, hours(2)); //2 hours after midnight
time_period tp(t1, t2);
tp.contains(t3); // true
time_period tp2(t1, t1);
tp2.contains(t1); // false</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>bool contains(time_period)</screen></entry>
<entry>True if period is within the period</entry>
</row>
<row>
<entry><screen>time_period tp1(ptime(d,hours(1)),
ptime(d,hours(12)));
time_period tp2(ptime(d,hours(2)),
ptime(d,hours(4)));
tp1.contains(tp2); // --> true
tp2.contains(tp1); // --> false</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>bool intersects(time_period)</screen></entry>
<entry> True if periods overlap</entry>
</row>
<row>
<entry><screen>time_period tp1(ptime(d,hours(1)),
ptime(d,hours(12)));
time_period tp2(ptime(d,hours(2)),
ptime(d,hours(4)));
tp2.intersects(tp1); // --> true</screen>
</entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>time_period intersection(time_period)</screen></entry>
<entry>Calculate the intersection of 2 periods. Null if no intersection.</entry>
</row>
<row>
<entry></entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>time_period merge(time_period)</screen></entry>
<entry>Returns union of two periods. Null if no intersection.</entry>
</row>
<row>
<entry></entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>time_period span(time_period)</screen></entry>
<entry>Combines two periods and any gap between them such that begin = min(p1.begin, p2.begin) and end = max(p1.end , p2.end).</entry>
</row>
<row>
<entry></entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
<anchor id="time_period_to_string" />
<bridgehead renderas="sect3">Conversion To String</bridgehead>
<para>
<informaltable frame="all">
<tgroup cols="2">
<thead>
<row>
<entry valign="top" morerows="1">Syntax</entry>
<entry>Description</entry>
</row>
<row>
<entry>Example</entry>
</row>
</thead>
<tbody>
<row>
<entry valign="top" morerows="1"><screen>std::string
to_simple_string(time_period dp)</screen></entry>
<entry>To <code>[YYYY-mmm-DD hh:mm:ss.fffffffff/YYYY-mmm-DD hh:mm:ss.fffffffff]</code> string where <code>mmm</code> is 3 char month name.</entry>
</row>
<row>
<entry><screen>[2002-Jan-01 01:25:10.000000001/
2002-Jan-31 01:25:10.123456789]
// string occupies one line</screen></entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
<anchor id="time_period_operators" />
<bridgehead renderas="sect3">Operators</bridgehead>
<para>
<informaltable frame="all">
<tgroup cols="2">
<thead>
<row>
<entry valign="top" morerows="1">Syntax</entry>
<entry>Description</entry>
</row>
<row>
<entry>Example</entry>
</row>
</thead>
<tbody>
<row>
<entry valign="top" morerows="1"><screen>operator<<</screen></entry>
<entry>Output streaming operator for time duration. Uses facet to output [date time_of_day/date time_of_day]. The default is format is <code>[YYYY-mmm-DD hh:mm:ss.fffffffff/YYYY-mmm-DD hh:mm:ss.fffffffff]</code> string where <code>mmm</code> is 3 char month name and the fractional seconds are left out when zero.</entry>
</row>
<row>
<entry><screen>[2002-Jan-01 01:25:10.000000001/ \
2002-Jan-31 01:25:10.123456789]</screen></entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>operator>></screen></entry>
<entry>Input streaming operator for time duration. Uses facet to read [date time_of_day/date time_of_day]. The default is format is <code>[YYYY-mmm-DD hh:mm:ss.fffffffff/YYYY-mmm-DD hh:mm:ss.fffffffff]</code> string where <code>mmm</code> is 3 char month name and the fractional seconds are left out when zero.</entry>
</row>
<row>
<entry><screen>[2002-Jan-01 01:25:10.000000001/ \
2002-Jan-31 01:25:10.123456789]</screen></entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>operator==, operator!=</screen></entry>
<entry>Equality operators. Periods are equal if p1.begin == p2.begin && p1.last == p2.last</entry>
</row>
<row>
<entry><screen>if (tp1 == tp2) {...</screen></entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>operator<</screen></entry>
<entry>Ordering with no overlap. True if tp1.end() less than tp2.begin()</entry>
</row>
<row>
<entry><screen>if (tp1 < tp2) {...</screen></entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>operator></screen></entry>
<entry>Ordering with no overlap. True if tp1.begin() greater than tp2.end()</entry>
</row>
<row>
<entry><screen>if (tp1 > tp2) {... etc</screen></entry>
</row>
<row>
<entry valign="top" morerows="1"><screen>operator<=, operator>=</screen></entry>
<entry>Defined in terms of the other operators.</entry>
</row>
<row>
<entry></entry>
</row>
</tbody>
</tgroup>
</informaltable>
</para>
</section>
|
