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<h2><span class="refentrytitle"><a name="grits-gpqueue.top_of_page"></a>gpqueue</span></h2>
<p>gpqueue — Priority queue implemention</p>
</td>
<td valign="top" align="right"></td>
</tr></table></div>
<div class="refsynopsisdiv">
<a name="grits-gpqueue.synopsis"></a><h2>Synopsis</h2>
<pre class="synopsis"> <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue">GPQueue</a>;
typedef <a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle">GPQueueHandle</a>;
<a class="link" href="grits-gpqueue.html#GPQueueNode" title="GPQueueNode">GPQueueNode</a>;
<span class="returnvalue">void</span> <a class="link" href="grits-gpqueue.html#g-pqueue-clear" title="g_pqueue_clear ()">g_pqueue_clear</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);
<span class="returnvalue">void</span> <a class="link" href="grits-gpqueue.html#g-pqueue-foreach" title="g_pqueue_foreach ()">g_pqueue_foreach</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GFunc"><span class="type">GFunc</span></a> func</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>);
<span class="returnvalue">void</span> <a class="link" href="grits-gpqueue.html#g-pqueue-free" title="g_pqueue_free ()">g_pqueue_free</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Pointer-Arrays.html#GPtrArray"><span class="returnvalue">GPtrArray</span></a> * <a class="link" href="grits-gpqueue.html#g-pqueue-get-array" title="g_pqueue_get_array ()">g_pqueue_get_array</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> <a class="link" href="grits-gpqueue.html#g-pqueue-is-empty" title="g_pqueue_is_empty ()">g_pqueue_is_empty</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);
<a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="returnvalue">GPQueue</span></a> * <a class="link" href="grits-gpqueue.html#g-pqueue-new" title="g_pqueue_new ()">g_pqueue_new</a> (<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GCompareDataFunc"><span class="type">GCompareDataFunc</span></a> compare_func</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> *compare_userdata</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="returnvalue">gpointer</span></a> <a class="link" href="grits-gpqueue.html#g-pqueue-peek" title="g_pqueue_peek ()">g_pqueue_peek</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);
<a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="returnvalue">gpointer</span></a> <a class="link" href="grits-gpqueue.html#g-pqueue-pop" title="g_pqueue_pop ()">g_pqueue_pop</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);
<span class="returnvalue">void</span> <a class="link" href="grits-gpqueue.html#g-pqueue-priority-changed" title="g_pqueue_priority_changed ()">g_pqueue_priority_changed</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> entry</code></em>);
<span class="returnvalue">void</span> <a class="link" href="grits-gpqueue.html#g-pqueue-priority-decreased" title="g_pqueue_priority_decreased ()">g_pqueue_priority_decreased</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> entry</code></em>);
<a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="returnvalue">GPQueueHandle</span></a> <a class="link" href="grits-gpqueue.html#g-pqueue-push" title="g_pqueue_push ()">g_pqueue_push</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> data</code></em>);
<span class="returnvalue">void</span> <a class="link" href="grits-gpqueue.html#g-pqueue-remove" title="g_pqueue_remove ()">g_pqueue_remove</a> (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> entry</code></em>);
</pre>
</div>
<div class="refsect1">
<a name="grits-gpqueue.description"></a><h2>Description</h2>
<p>
</p>
<p>
The <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> structure and its associated functions provide a sorted
collection of objects. Entries can be inserted in any order and at any time,
and an entry's priority can be changed after it has been inserted into the
queue. Entries are supposed to be removed one at a time in order of priority
with <a class="link" href="grits-gpqueue.html#g-pqueue-pop" title="g_pqueue_pop ()"><code class="function">g_pqueue_pop()</code></a>, but deleting entries out of order is possible.
</p>
<p>
</p>
<p>
The entries <span class="emphasis"><em>cannot</em></span> be iterated over in any way other
than removing them one by one in order of priority, but when doing that,
this structure is far more efficient than sorted lists or balanced trees,
which on the other hand do not suffer from this restriction.
</p>
<p>
</p>
<p>
You will want to be very careful with calls that use <a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a>.
Handles immediately become invalid when an entry is removed from a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>,
but the current implementation cannot detect this and will do unfortunate
things to undefined memory locations if you try to use an invalid handle.
</p>
<p>
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>
Internally, <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> currently uses a Fibonacci heap to store
the entries. This implementation detail may change.
</p>
</div>
<p>
</p>
</div>
<div class="refsect1">
<a name="grits-gpqueue.details"></a><h2>Details</h2>
<div class="refsect2">
<a name="GPQueue"></a><h3>GPQueue</h3>
<pre class="programlisting">typedef struct _GPQueue GPQueue;</pre>
<p>
An opaque structure representing a priority queue.
</p>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="GPQueueHandle"></a><h3>GPQueueHandle</h3>
<pre class="programlisting">typedef GPQueueNode* GPQueueHandle;
</pre>
<p>
An opaque value representing one entry in a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.
</p>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="GPQueueNode"></a><h3>GPQueueNode</h3>
<pre class="programlisting">typedef struct _GPQueueNode GPQueueNode;</pre>
<p>
</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-clear"></a><h3>g_pqueue_clear ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> g_pqueue_clear (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);</pre>
<p>
Removes all entries from a <em class="parameter"><code>pqueue</code></em>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr></tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-foreach"></a><h3>g_pqueue_foreach ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> g_pqueue_foreach (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GFunc"><span class="type">GFunc</span></a> func</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> user_data</code></em>);</pre>
<p>
Calls func for each element in the pqueue passing user_data to the function.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td> a <a href="http://library.gnome.org/devel/glib/unstable/glib-Double-ended-Queues.html#GQueue"><span class="type">GQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>func</code></em> :</span></p></td>
<td>the function to call for each element's data</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>user_data</code></em> :</span></p></td>
<td>user data to pass to func</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-free"></a><h3>g_pqueue_free ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> g_pqueue_free (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);</pre>
<p>
Deallocates the memory used by <em class="parameter"><code>pqueue</code></em> itself, but not any memory pointed
to by the data pointers of its entries.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody><tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr></tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-get-array"></a><h3>g_pqueue_get_array ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Pointer-Arrays.html#GPtrArray"><span class="returnvalue">GPtrArray</span></a> * g_pqueue_get_array (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);</pre>
<p>
Construct a GPtrArray for the items in pqueue. This can be useful when
updating the priorities of all the elements in pqueue.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td> a <a href="http://library.gnome.org/devel/glib/unstable/glib-Double-ended-Queues.html#GQueue"><span class="type">GQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>A GPtrArray containing a pointer to each item in pqueue</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-is-empty"></a><h3>g_pqueue_is_empty ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gboolean"><span class="returnvalue">gboolean</span></a> g_pqueue_is_empty (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);</pre>
<p>
Returns <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the queue is empty.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>
<a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#TRUE:CAPS"><code class="literal">TRUE</code></a> if the queue is empty.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-new"></a><h3>g_pqueue_new ()</h3>
<pre class="programlisting"><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="returnvalue">GPQueue</span></a> * g_pqueue_new (<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GCompareDataFunc"><span class="type">GCompareDataFunc</span></a> compare_func</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> *compare_userdata</code></em>);</pre>
<p>
Creates a new <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>compare_func</code></em> :</span></p></td>
<td>the <a href="http://library.gnome.org/devel/glib/unstable/glib-Doubly-Linked-Lists.html#GCompareDataFunc"><span class="type">GCompareDataFunc</span></a> used to sort the new priority queue.
This function is passed two elements of the queue and should return 0 if
they are equal, a negative value if the first comes before the second, and
a positive value if the second comes before the first.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>compare_userdata</code></em> :</span></p></td>
<td>user data passed to <em class="parameter"><code>compare_func</code></em>
</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>a new <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-peek"></a><h3>g_pqueue_peek ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="returnvalue">gpointer</span></a> g_pqueue_peek (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);</pre>
<p>
Returns the topmost entry's data pointer, or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the queue is empty.
</p>
<p>
If you need to tell the difference between an empty queue and a queue
that happens to have a <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> pointer at the top, check if the queue is
empty first.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>the topmost entry's data pointer, or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the queue is empty.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-pop"></a><h3>g_pqueue_pop ()</h3>
<pre class="programlisting"><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="returnvalue">gpointer</span></a> g_pqueue_pop (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>);</pre>
<p>
Removes the topmost entry from a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> and returns its data pointer.
Calling this on an empty <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> is not an error, but removes nothing
and returns <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a>.
</p>
<p>
If you need to tell the difference between an empty queue and a queue
that happens to have a <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> pointer at the top, check if the queue is
empty first.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>the topmost entry's data pointer, or <a href="http://library.gnome.org/devel/glib/unstable/glib-Standard-Macros.html#NULL:CAPS"><code class="literal">NULL</code></a> if the queue was empty.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-priority-changed"></a><h3>g_pqueue_priority_changed ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> g_pqueue_priority_changed (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> entry</code></em>);</pre>
<p>
Notifies the <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> that the priority of one entry has changed.
The internal representation is updated accordingly.
</p>
<p>
Make sure that <em class="parameter"><code>entry</code></em> refers to an entry that is actually part of
<em class="parameter"><code>pqueue</code></em> at the time, otherwise the behavior of this function is
undefined (expect crashes).
</p>
<p>
Do not attempt to change the priorities of several entries at once.
Every time a single object is changed, the <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> needs to be updated
by calling <a class="link" href="grits-gpqueue.html#g-pqueue-priority-changed" title="g_pqueue_priority_changed ()"><code class="function">g_pqueue_priority_changed()</code></a> for that object.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>entry</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> for an entry in <em class="parameter"><code>pqueue</code></em>.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-priority-decreased"></a><h3>g_pqueue_priority_decreased ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> g_pqueue_priority_decreased (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> entry</code></em>);</pre>
<p>
Notifies the <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> that the priority of one entry has
<span class="emphasis"><em>decreased</em></span>.
</p>
<p>
This is a special case of <a class="link" href="grits-gpqueue.html#g-pqueue-priority-changed" title="g_pqueue_priority_changed ()"><code class="function">g_pqueue_priority_changed()</code></a>. If you are absolutely
sure that the new priority of <em class="parameter"><code>entry</code></em> is lower than it was before, you
may call this function instead of <a class="link" href="grits-gpqueue.html#g-pqueue-priority-changed" title="g_pqueue_priority_changed ()"><code class="function">g_pqueue_priority_changed()</code></a>.
</p>
<p>
</p>
<div class="note" style="margin-left: 0.5in; margin-right: 0.5in;">
<h3 class="title">Note</h3>
<p>
In the current implementation, an expensive step in
<a class="link" href="grits-gpqueue.html#g-pqueue-priority-changed" title="g_pqueue_priority_changed ()"><code class="function">g_pqueue_priority_changed()</code></a> can be skipped if the new priority is known
to be lower, leading to an amortized running time of O(1) instead of
O(log n). Of course, if the priority is not actually lower, behavior
is undefined.
</p>
</div>
<p>
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>entry</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> for an entry in <em class="parameter"><code>pqueue</code></em>.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-push"></a><h3>g_pqueue_push ()</h3>
<pre class="programlisting"><a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="returnvalue">GPQueueHandle</span></a> g_pqueue_push (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a href="http://library.gnome.org/devel/glib/unstable/glib-Basic-Types.html#gpointer"><span class="type">gpointer</span></a> data</code></em>);</pre>
<p>
Inserts a new entry into a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.
</p>
<p>
The returned handle can be used in calls to <a class="link" href="grits-gpqueue.html#g-pqueue-remove" title="g_pqueue_remove ()"><code class="function">g_pqueue_remove()</code></a> and
<a class="link" href="grits-gpqueue.html#g-pqueue-priority-changed" title="g_pqueue_priority_changed ()"><code class="function">g_pqueue_priority_changed()</code></a>. Never make such calls for entries that have
already been removed from the queue. The same <em class="parameter"><code>data</code></em> can be inserted into
a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> more than once, but remember that in this case,
<a class="link" href="grits-gpqueue.html#g-pqueue-priority-changed" title="g_pqueue_priority_changed ()"><code class="function">g_pqueue_priority_changed()</code></a> needs to be called for
<span class="emphasis"><em>every</em></span> handle for that object if its priority changes.
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>data</code></em> :</span></p></td>
<td>the object to insert into the priority queue.</td>
</tr>
<tr>
<td><p><span class="term"><span class="emphasis"><em>Returns</em></span> :</span></p></td>
<td>a handle for the freshly inserted entry.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
<hr>
<div class="refsect2">
<a name="g-pqueue-remove"></a><h3>g_pqueue_remove ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span> g_pqueue_remove (<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a> *pqueue</code></em>,
<em class="parameter"><code><a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> entry</code></em>);</pre>
<p>
Removes one entry from a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.
</p>
<p>
Make sure that <em class="parameter"><code>entry</code></em> refers to an entry that is actually part of
<em class="parameter"><code>pqueue</code></em> at the time, otherwise the behavior of this function is
undefined (expect crashes).
</p>
<div class="variablelist"><table border="0" class="variablelist">
<colgroup>
<col align="left" valign="top">
<col>
</colgroup>
<tbody>
<tr>
<td><p><span class="term"><em class="parameter"><code>pqueue</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueue" title="GPQueue"><span class="type">GPQueue</span></a>.</td>
</tr>
<tr>
<td><p><span class="term"><em class="parameter"><code>entry</code></em> :</span></p></td>
<td>a <a class="link" href="grits-gpqueue.html#GPQueueHandle" title="GPQueueHandle"><span class="type">GPQueueHandle</span></a> for an entry in <em class="parameter"><code>pqueue</code></em>.</td>
</tr>
</tbody>
</table></div>
<p class="since">Since 2.x</p>
</div>
</div>
</div>
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