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<div class="refentry" title="Class template period">
<a name="boost.date_time.period"></a><div class="titlepage"></div>
<div class="refnamediv">
<h2><span class="refentrytitle">Class template period</span></h2>
<p>boost::date_time::period — Provides generalized period type useful in date-time systems. </p>
</div>
<h2 xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv-title">Synopsis</h2>
<div xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="refsynopsisdiv"><pre class="synopsis"><span class="emphasis"><em>// In header: <<a class="link" href="../../date_time/doxy.html#header.boost.date_time.period_hpp" title="Header <boost/date_time/period.hpp>">boost/date_time/period.hpp</a>>
</em></span><span class="bold"><strong>template</strong></span><<span class="bold"><strong>typename</strong></span> point_rep, <span class="bold"><strong>typename</strong></span> duration_rep>
<span class="bold"><strong>class</strong></span> <a class="link" href="period.html" title="Class template period">period</a> {
<span class="bold"><strong>public</strong></span>:
<span class="emphasis"><em>// types</em></span>
<span class="bold"><strong>typedef</strong></span> point_rep <a name="boost.date_time.period.point_type"></a>point_type;
<span class="bold"><strong>typedef</strong></span> duration_rep <a name="boost.date_time.period.duration_type"></a>duration_type;
<span class="emphasis"><em>// <a class="link" href="period.html#boost.date_time.periodconstruct-copy-destruct">construct/copy/destruct</a></em></span>
<a class="link" href="period.html#id355985-bb">period</a>(point_rep, point_rep);
<a class="link" href="period.html#id392891-bb">period</a>(point_rep, duration_rep);
<span class="emphasis"><em>// <a class="link" href="period.html#id370525-bb">public member functions</a></em></span>
<span class="type">point_rep</span> <a class="link" href="period.html#id370528-bb">begin</a>() <span class="bold"><strong>const</strong></span>;
<span class="type">point_rep</span> <a class="link" href="period.html#id349913-bb">end</a>() <span class="bold"><strong>const</strong></span>;
<span class="type">point_rep</span> <a class="link" href="period.html#id387958-bb">last</a>() <span class="bold"><strong>const</strong></span>;
<span class="type">duration_rep</span> <a class="link" href="period.html#id607172-bb">length</a>() <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id607182-bb">is_null</a>() <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id398706-bb"><span class="bold"><strong>operator</strong></span>==</a>(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> &) <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id393695-bb"><span class="bold"><strong>operator</strong></span><</a>(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> &) <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>void</strong></span></span> <a class="link" href="period.html#id393715-bb">shift</a>(<span class="bold"><strong>const</strong></span> duration_rep &) ;
<span class="type"><span class="bold"><strong>void</strong></span></span> <a class="link" href="period.html#id374215-bb">expand</a>(<span class="bold"><strong>const</strong></span> duration_rep &) ;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id335527-bb">contains</a>(<span class="bold"><strong>const</strong></span> point_rep &) <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id409424-bb">contains</a>(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> &) <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id360584-bb">intersects</a>(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> &) <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id396783-bb">is_adjacent</a>(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> &) <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id366165-bb">is_before</a>(<span class="bold"><strong>const</strong></span> point_rep &) <span class="bold"><strong>const</strong></span>;
<span class="type"><span class="bold"><strong>bool</strong></span></span> <a class="link" href="period.html#id366182-bb">is_after</a>(<span class="bold"><strong>const</strong></span> point_rep &) <span class="bold"><strong>const</strong></span>;
<span class="type"><a class="link" href="period.html" title="Class template period">period</a></span> <a class="link" href="period.html#id366199-bb">intersection</a>(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> &) <span class="bold"><strong>const</strong></span>;
<span class="type"><a class="link" href="period.html" title="Class template period">period</a></span> <a class="link" href="period.html#id366221-bb">merge</a>(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> &) <span class="bold"><strong>const</strong></span>;
<span class="type"><a class="link" href="period.html" title="Class template period">period</a></span> <a class="link" href="period.html#id355953-bb">span</a>(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> &) <span class="bold"><strong>const</strong></span>;
};</pre></div>
<div class="refsect1" title="Description">
<a name="id810921"></a><h2>Description</h2>
<p>This template uses a class to represent a time point within the period and another class to represent a duration. As a result, this class is not appropriate for use when the number and duration representation are the same (eg: in the regular number domain).</p>
<p>A period can be specified by providing either the begining point and a duration or the begining point and the end point( end is NOT part of the period but 1 unit past it. A period will be "invalid" if either end_point <= begin_point or the given duration is <= 0. Any valid period will return false for is_null().</p>
<p>Zero length periods are also considered invalid. Zero length periods are periods where the begining and end points are the same, or, the given duration is zero. For a zero length period, the last point will be one unit less than the begining point.</p>
<p>In the case that the begin and last are the same, the period has a length of one unit.</p>
<p>The best way to handle periods is usually to provide a begining point and a duration. So, day1 + 7 days is a week period which includes all of the first day and 6 more days (eg: Sun to Sat). </p>
<div class="refsect2" title="period public construct/copy/destruct">
<a name="id810960"></a><h3>
<a name="boost.date_time.periodconstruct-copy-destruct"></a><code class="computeroutput">period</code>
public
construct/copy/destruct</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><a name="id355985-bb"></a>period(point_rep first_point, point_rep end_point);</pre>create a period from begin to last eg: [begin,end) <p>If end <= begin then the period will be invalid </p>
</li>
<li class="listitem">
<pre class="literallayout"><a name="id392891-bb"></a>period(point_rep first_point, duration_rep len);</pre>create a period as [begin, begin+len) <p>If len is <= 0 then the period will be invalid </p>
</li>
</ol></div>
</div>
<div class="refsect2" title="period public member functions">
<a name="id811016"></a><h3>
<a name="id370525-bb"></a><code class="computeroutput">period</code> public member functions</h3>
<div class="orderedlist"><ol class="orderedlist" type="1">
<li class="listitem">
<pre class="literallayout"><span class="type">point_rep</span> <a name="id370528-bb"></a>begin() <span class="bold"><strong>const</strong></span>;</pre>Return the first element in the period. </li>
<li class="listitem">
<pre class="literallayout"><span class="type">point_rep</span> <a name="id349913-bb"></a>end() <span class="bold"><strong>const</strong></span>;</pre>Return one past the last element. </li>
<li class="listitem">
<pre class="literallayout"><span class="type">point_rep</span> <a name="id387958-bb"></a>last() <span class="bold"><strong>const</strong></span>;</pre>Return the last item in the period. </li>
<li class="listitem">
<pre class="literallayout"><span class="type">duration_rep</span> <a name="id607172-bb"></a>length() <span class="bold"><strong>const</strong></span>;</pre>Return the length of the period. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id607182-bb"></a>is_null() <span class="bold"><strong>const</strong></span>;</pre>True if period is ill formed (length is zero or less). </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id398706-bb"></a><span class="bold"><strong>operator</strong></span>==(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> & rhs) <span class="bold"><strong>const</strong></span>;</pre>Equality operator. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id393695-bb"></a><span class="bold"><strong>operator</strong></span><(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> & rhs) <span class="bold"><strong>const</strong></span>;</pre>Strict as defined by rhs.last <= lhs.last. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>void</strong></span></span> <a name="id393715-bb"></a>shift(<span class="bold"><strong>const</strong></span> duration_rep & d) ;</pre>Shift the start and end by the specified amount. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>void</strong></span></span> <a name="id374215-bb"></a>expand(<span class="bold"><strong>const</strong></span> duration_rep & d) ;</pre>
<p>Expands the size of the period by the duration on both ends.</p>
<p>So before expand </p>
<pre class="programlisting"> [-------]
^ ^ ^ ^ ^ ^ ^
1 2 3 4 5 6 7
*
</pre>
<p> After expand(2) </p>
<pre class="programlisting"> [----------------------]
^ ^ ^ ^ ^ ^ ^
1 2 3 4 5 6 7
*
</pre>
<p> </p>
</li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id335527-bb"></a>contains(<span class="bold"><strong>const</strong></span> point_rep & point) <span class="bold"><strong>const</strong></span>;</pre>True if the point is inside the period, zero length periods contain no points. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id409424-bb"></a>contains(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> & other) <span class="bold"><strong>const</strong></span>;</pre>True if this period fully contains (or equals) the other period. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id360584-bb"></a>intersects(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> & other) <span class="bold"><strong>const</strong></span>;</pre>True if the periods overlap in any way. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id396783-bb"></a>is_adjacent(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> & other) <span class="bold"><strong>const</strong></span>;</pre>True if periods are next to each other without a gap. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id366165-bb"></a>is_before(<span class="bold"><strong>const</strong></span> point_rep & point) <span class="bold"><strong>const</strong></span>;</pre>True if all of the period is prior to the passed point or end <= t. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><span class="bold"><strong>bool</strong></span></span> <a name="id366182-bb"></a>is_after(<span class="bold"><strong>const</strong></span> point_rep & point) <span class="bold"><strong>const</strong></span>;</pre>True if all of the period is prior or t < start. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><a class="link" href="period.html" title="Class template period">period</a></span> <a name="id366199-bb"></a>intersection(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> & other) <span class="bold"><strong>const</strong></span>;</pre>Returns the period of intersection or invalid range no intersection. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><a class="link" href="period.html" title="Class template period">period</a></span> <a name="id366221-bb"></a>merge(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> & other) <span class="bold"><strong>const</strong></span>;</pre>Returns the union of intersecting periods -- or null period. </li>
<li class="listitem">
<pre class="literallayout"><span class="type"><a class="link" href="period.html" title="Class template period">period</a></span> <a name="id355953-bb"></a>span(<span class="bold"><strong>const</strong></span> <a class="link" href="period.html" title="Class template period">period</a> & other) <span class="bold"><strong>const</strong></span>;</pre>Combine two periods with earliest start and latest end. <p>Combines two periods and any gap between them such that start = min(p1.start, p2.start) end = max(p1.end , p2.end) </p>
<pre class="programlisting"> [---p1---)
[---p2---)
result:
[-----------p3----------)
*
</pre>
<p> </p>
</li>
</ol></div>
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