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| <!DOCTYPE library PUBLIC "-//Boost//DTD BoostBook XML V1.0//EN" |
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| |
| <!-- Copyright (c) 2001-2005 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.local_time.local_time_period"> |
| <title>Local Time Period</title> |
| |
| <link linkend="local_time_period_intro">Introduction</link> -- |
| <link linkend="local_time_period_header">Header</link> -- |
| <link linkend="local_time_period_constr">Construction</link> -- |
| <link linkend="local_time_period_accessors">Accessors</link> -- |
| <link linkend="local_time_period_operators">Operators</link> |
| |
| <anchor id="local_time_period_intro" /> |
| <bridgehead renderas="sect3">Introduction</bridgehead> |
| <para> |
| The class <code>boost::local_time::local_time_period</code> provides direct representation for ranges between two local 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> |
| |
| <anchor id="local_time_period_header" /> |
| <bridgehead renderas="sect3">Header</bridgehead> |
| <para> |
| <programlisting>#include "boost/date_time/local_time/local_time.hpp" //include all types plus i/o |
| or |
| #include "boost/date_time/local_time/local_time_types.hpp" //no i/o just types</programlisting> |
| </para> |
| |
| <anchor id="local_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>local_time_period(...) |
| Parameters: |
| local_date_time beginning |
| local_date_time end</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>time_zone_ptr |
| zone(new posix_time_zone("MST-07")); |
| local_date_time |
| beg(ptime(date(2005,Jan,1),hours(0)), zone); |
| local_date_time |
| end(ptime(date(2005,Feb,1),hours(0)), zone); |
| // period for the entire month of Jan 2005 |
| local_time_period ltp(beg, end);</screen> |
| </entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>local_time_period(...) |
| Parameters: |
| local_date_time beginning |
| time_duration length</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>time_zone_ptr |
| zone(new posix_time_zone("MST-07")); |
| local_date_time |
| beg(ptime(date(2005,Jan,1),hours(0)), zone); |
| // period for the whole day of 2005-Jan-01 |
| local_time_period ltp(beg, hours(24));</screen> |
| </entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>local_time_period(local_time_period rhs)</screen></entry> |
| <entry>Copy constructor</entry> |
| </row> |
| <row> |
| <entry><screen>local_time_period ltp1(ltp);</screen></entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </informaltable> |
| </para> |
| |
| |
| <anchor id="local_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>local_date_time begin()</screen></entry> |
| <entry>Return first local_date_time of the period.</entry> |
| </row> |
| <row> |
| <entry><screen>time_zone_ptr |
| zone(new posix_time_zone("MST-07")); |
| local_date_time |
| ldt((ptime(date(2005,Jan,1)),hours(0)), zone); |
| local_time_period ltp(ldt, hours(2)); |
| ltp.begin(); // => 2005-Jan-01 00:00:00</screen> |
| </entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>local_date_time last()</screen></entry> |
| <entry>Return last local_date_time in the period</entry> |
| </row> |
| <row> |
| <entry><screen>time_zone_ptr |
| zone(new posix_time_zone("MST-07")); |
| local_date_time |
| ldt((ptime(date(2005,Jan,1),hours(0))), zone); |
| local_time_period ltp(ldt, hours(2)); |
| ltp.last(); // => 2005-Jan-01 01:59:59.999999999</screen> |
| </entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>local_date_time end()</screen></entry> |
| <entry>Return one past the last in period</entry> |
| </row> |
| <row> |
| <entry><screen>time_zone_ptr |
| zone(new posix_time_zone("MST-07")); |
| local_date_time |
| ldt((ptime(date(2005,Jan,1),hours(0))), zone); |
| local_time_period ltp(ldt, hours(2)); |
| ltp.end(); // => 2005-Jan-01 02:00:00</screen> |
| </entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>time_duration length()</screen></entry> |
| <entry>Return the length of the local_time period.</entry> |
| </row> |
| <row> |
| <entry><screen>time_zone_ptr |
| zone(new posix_time_zone("MST-07")); |
| local_date_time |
| ldt((ptime(date(2005,Jan,1),hours(0))), zone); |
| local_time_period ltp(ldt, hours(2)); |
| ltp.length(); // => 02:00:00</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 less than or equal to begin.</entry> |
| </row> |
| <row> |
| <entry><screen>time_zone_ptr |
| zone(new posix_time_zone("MST-07")); |
| local_date_time |
| beg((ptime(date(2005,Feb,1),hours(0))), zone); |
| local_date_time |
| end((ptime(date(2005,Jan,1),hours(0))), zone); |
| local_time_period ltp(beg, end); |
| ltp.is_null(); // => true</screen> |
| </entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>bool contains(local_date_time)</screen></entry> |
| <entry>True if local_date_time is within the period. Zero length periods cannot contain any points</entry> |
| </row> |
| <row> |
| <entry><screen>time_zone_ptr |
| zone(new posix_time_zone("MST-07")); |
| local_date_time |
| beg((ptime(date(2005,Jan,1),hours(0))), zone); |
| local_date_time |
| end((ptime(date(2005,Feb,1),hours(0))), zone); |
| local_time_period jan_mst(beg, end); |
| |
| local_date_time |
| ldt((ptime(date(2005,Jan,15),hours(12))), zone); |
| jan_mst.contains(ldt); // => true |
| |
| local_time_period zero(beg, beg); |
| zero.contains(beg); // false</screen></entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>bool contains(local_time_period)</screen></entry> |
| <entry>True if period is within the period</entry> |
| </row> |
| <row> |
| <entry><screen>// using jan_mst period from previous example |
| |
| local_date_time |
| beg((ptime(date(2005,Jan,7),hours(0))), zone); |
| local_time_period ltp(beg, hours(24)); |
| |
| jan_mst.contains(ltp); // => true</screen></entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>bool intersects(local_time_period)</screen></entry> |
| <entry> True if periods overlap</entry> |
| </row> |
| <row> |
| <entry><screen>// using jan_mst period from previous example |
| |
| local_date_time |
| beg((ptime(date(2005,Jan,7),hours(0))), zone); |
| local_date_time |
| end((ptime(date(2005,Feb,7),hours(0))), zone); |
| local_time_period ltp(beg, end); |
| |
| jan_mst.intersects(ltp); // => true</screen></entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>local_time_period intersection(local_time_period)</screen></entry> |
| <entry>Calculate the intersection of 2 periods. Null if no intersection.</entry> |
| </row> |
| <row> |
| <entry><screen>// using jan_mst period from previous example |
| |
| local_date_time |
| beg((ptime(date(2005,Jan,7),hours(0))), zone); |
| local_date_time |
| end((ptime(date(2005,Feb,7),hours(0))), zone); |
| local_time_period ltp(beg, end); |
| |
| local_time_period res(jan_mst.intersection(ltp)); |
| // res => 2005-Jan-07 00:00:00 through |
| // 2005-Jan-31 23:59:59.999999999 (inclusive)</screen></entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>local_time_period merge(local_time_period)</screen></entry> |
| <entry>Returns union of two periods. Null if no intersection.</entry> |
| </row> |
| <row> |
| <entry><screen>// using jan_mst period from previous example |
| |
| local_date_time |
| beg((ptime(date(2005,Jan,7),hours(0))), zone); |
| local_date_time |
| end((ptime(date(2005,Feb,7),hours(0))), zone); |
| local_time_period ltp(beg, end); |
| |
| local_time_period res(jan_mst.merge(ltp)); |
| // res => 2005-Jan-07 00:00:00 through |
| // 2005-Feb-06 23:59:59.999999999 (inclusive)</screen></entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>local_time_period span(local_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><screen>// using jan_mst period from previous example |
| |
| local_date_time |
| beg((ptime(date(2005,Mar,1),hours(0))), zone); |
| local_date_time |
| end((ptime(date(2005,Apr,1),hours(0))), zone); |
| local_time_period mar_mst(beg, end); |
| |
| local_time_period res(jan_mst.span(mar_mst)); |
| // res => 2005-Jan-01 00:00:00 through |
| // 2005-Mar-31 23:59:59.999999999 (inclusive)</screen></entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>void shift(time_duration)</screen></entry> |
| <entry>Add duration to both begin and end.</entry> |
| </row> |
| <row> |
| <entry><screen>local_date_time |
| beg((ptime(date(2005,Mar,1),hours(0))), zone); |
| local_date_time |
| end((ptime(date(2005,Apr,1),hours(0))), zone); |
| local_time_period mar_mst(beg, end); |
| |
| mar_mst.shift(hours(48)); |
| // mar_mst => 2005-Mar-03 00:00:00 through |
| // 2005-Apr-02 23:59:59.999999999 (inclusive)</screen></entry> |
| </row> |
| </tbody> |
| </tgroup> |
| </informaltable> |
| </para> |
| |
| |
| <anchor id="local_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> |
| <!-- TODO: the streaming operators have not bee changed from time_period to local_time_period |
| <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 ltp1.begin == ltp2.begin && ltp1.last == ltp2.last</entry> |
| </row> |
| <row> |
| <entry><screen>if (ltp1 == ltp2) {...</screen></entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>operator<</screen></entry> |
| <entry>Ordering with no overlap. True if ltp1.end() less than ltp2.begin()</entry> |
| </row> |
| <row> |
| <entry><screen>if (ltp1 < ltp2) {...</screen></entry> |
| </row> |
| |
| <row> |
| <entry valign="top" morerows="1"><screen>operator></screen></entry> |
| <entry>Ordering with no overlap. True if ltp1.begin() greater than ltp2.end()</entry> |
| </row> |
| <row> |
| <entry><screen>if (ltp1 > ltp2) {... 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> |
