You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
tqt3/doc/html/ntqptrdict.html

317 lines
15 KiB

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/doc/qptrdict.doc:41 -->
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
<title>TQPtrDict Class</title>
<style type="text/css"><!--
fn { margin-left: 1cm; text-indent: -1cm; }
a:link { color: #004faf; text-decoration: none }
a:visited { color: #672967; text-decoration: none }
body { background: #ffffff; color: black; }
--></style>
</head>
<body>
<table border="0" cellpadding="0" cellspacing="0" width="100%">
<tr bgcolor="#E5E5E5">
<td valign=center>
<a href="index.html">
<font color="#004faf">Home</font></a>
| <a href="classes.html">
<font color="#004faf">All&nbsp;Classes</font></a>
| <a href="mainclasses.html">
<font color="#004faf">Main&nbsp;Classes</font></a>
| <a href="annotated.html">
<font color="#004faf">Annotated</font></a>
| <a href="groups.html">
<font color="#004faf">Grouped&nbsp;Classes</font></a>
| <a href="functions.html">
<font color="#004faf">Functions</font></a>
</td>
<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>TQPtrDict Class Reference</h1>
<p>The TQPtrDict class is a template class that provides a dictionary based on void* keys.
<a href="#details">More...</a>
<p><tt>#include &lt;<a href="qptrdict-h.html">ntqptrdict.h</a>&gt;</tt>
<p>Inherits <a href="ntqptrcollection.html">TQPtrCollection</a>.
<p><a href="qptrdict-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li class=fn><a href="#TQPtrDict"><b>TQPtrDict</b></a> ( int&nbsp;size = 17 )</li>
<li class=fn><a href="#TQPtrDict-2"><b>TQPtrDict</b></a> ( const&nbsp;TQPtrDict&lt;type&gt;&nbsp;&amp;&nbsp;dict )</li>
<li class=fn><a href="#~TQPtrDict"><b>~TQPtrDict</b></a> ()</li>
<li class=fn>TQPtrDict&lt;type&gt; &amp; <a href="#operator-eq"><b>operator=</b></a> ( const&nbsp;TQPtrDict&lt;type&gt;&nbsp;&amp;&nbsp;dict )</li>
<li class=fn>virtual uint <a href="#count"><b>count</b></a> () const</li>
<li class=fn>uint <a href="#size"><b>size</b></a> () const</li>
<li class=fn>bool <a href="#isEmpty"><b>isEmpty</b></a> () const</li>
<li class=fn>void <a href="#insert"><b>insert</b></a> ( void&nbsp;*&nbsp;key, const&nbsp;type&nbsp;*&nbsp;item )</li>
<li class=fn>void <a href="#replace"><b>replace</b></a> ( void&nbsp;*&nbsp;key, const&nbsp;type&nbsp;*&nbsp;item )</li>
<li class=fn>bool <a href="#remove"><b>remove</b></a> ( void&nbsp;*&nbsp;key )</li>
<li class=fn>type * <a href="#take"><b>take</b></a> ( void&nbsp;*&nbsp;key )</li>
<li class=fn>type * <a href="#find"><b>find</b></a> ( void&nbsp;*&nbsp;key ) const</li>
<li class=fn>type * <a href="#operator[]"><b>operator[]</b></a> ( void&nbsp;*&nbsp;key ) const</li>
<li class=fn>virtual void <a href="#clear"><b>clear</b></a> ()</li>
<li class=fn>void <a href="#resize"><b>resize</b></a> ( uint&nbsp;newsize )</li>
<li class=fn>void <a href="#statistics"><b>statistics</b></a> () const</li>
</ul>
<h2>Important Inherited Members</h2>
<ul>
<li class=fn>bool <a href="#autoDelete"><b>autoDelete</b></a> () const</li>
<li class=fn>void <a href="#setAutoDelete"><b>setAutoDelete</b></a> ( bool&nbsp;enable )</li>
</ul>
<h2>Protected Members</h2>
<ul>
<li class=fn>virtual TQDataStream &amp; <a href="#read"><b>read</b></a> ( TQDataStream&nbsp;&amp;&nbsp;s, TQPtrCollection::Item&nbsp;&amp;&nbsp;item )</li>
<li class=fn>virtual TQDataStream &amp; <a href="#write"><b>write</b></a> ( TQDataStream&nbsp;&amp;&nbsp;s, TQPtrCollection::Item ) const</li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
The TQPtrDict class is a template class that provides a dictionary based on void* keys.
<p>
<p>
<p> TQPtrDict is implemented as a template class. Define a template
instance TQPtrDict&lt;X&gt; to create a dictionary that operates on
pointers to X (X*).
<p> A dictionary is a collection of key-value pairs. The key is a
void* used for insertion, removal and lookup. The value is a
pointer. Dictionaries provide very fast insertion and lookup.
<p> Example:
<pre>
TQPtrDict&lt;char&gt; fields; // void* keys, char* values
<a href="ntqlineedit.html">TQLineEdit</a> *le1 = new <a href="ntqlineedit.html">TQLineEdit</a>( this );
le1-&gt;<a href="ntqlineedit.html#setText">setText</a>( "Simpson" );
<a href="ntqlineedit.html">TQLineEdit</a> *le2 = new <a href="ntqlineedit.html">TQLineEdit</a>( this );
le2-&gt;<a href="ntqlineedit.html#setText">setText</a>( "Homer" );
<a href="ntqlineedit.html">TQLineEdit</a> *le3 = new <a href="ntqlineedit.html">TQLineEdit</a>( this );
le3-&gt;<a href="ntqlineedit.html#setText">setText</a>( "45" );
fields.<a href="#insert">insert</a>( le1, "Surname" );
fields.<a href="#insert">insert</a>( le2, "Forename" );
fields.<a href="#insert">insert</a>( le3, "Age" );
<a href="qptrdictiterator.html">TQPtrDictIterator</a>&lt;char&gt; it( fields );
for( ; it.<a href="qptrdictiterator.html#current">current</a>(); ++it )
cout &lt;&lt; it.<a href="qptrdictiterator.html#current">current</a>() &lt;&lt; endl;
cout &lt;&lt; endl;
if ( fields[le1] ) // Prints "Surname: Simpson"
cout &lt;&lt; fields[le1] &lt;&lt; ": " &lt;&lt; le1-&gt;<a href="ntqlineedit.html#text">text</a>() &lt;&lt; endl;
if ( fields[le2] ) // Prints "Forename: Homer"
cout &lt;&lt; fields[le2] &lt;&lt; ": " &lt;&lt; le2-&gt;<a href="ntqlineedit.html#text">text</a>() &lt;&lt; endl;
fields.<a href="#remove">remove</a>( le1 ); // Removes le1 from the dictionary
cout &lt;&lt; le1-&gt;<a href="ntqlineedit.html#text">text</a>() &lt;&lt; endl; // Prints "Simpson"
</pre>
In this example we use a dictionary to add an extra property (a
char*) to the line edits we're using.
<p> See <a href="ntqdict.html">TQDict</a> for full details, including the choice of dictionary
size, and how deletions are handled.
<p> <p>See also <a href="qptrdictiterator.html">TQPtrDictIterator</a>, <a href="ntqdict.html">TQDict</a>, <a href="ntqasciidict.html">TQAsciiDict</a>, <a href="ntqintdict.html">TQIntDict</a>, <a href="collection.html">Collection Classes</a>, <a href="collection.html">Collection Classes</a>, and <a href="tools.html">Non-GUI Classes</a>.
<hr><h2>Member Function Documentation</h2>
<h3 class=fn><a name="TQPtrDict"></a>TQPtrDict::TQPtrDict ( int&nbsp;size = 17 )
</h3>
<p> Constructs a dictionary using an internal hash array with the size
<em>size</em>.
<p> Setting <em>size</em> to a suitably large <a href="primes.html#prime">prime</a> number (equal to or
greater than the expected number of entries) makes the hash
distribution better and improves lookup performance.
<h3 class=fn><a name="TQPtrDict-2"></a>TQPtrDict::TQPtrDict ( const&nbsp;<a href="ntqptrdict.html">TQPtrDict</a>&lt;type&gt;&nbsp;&amp;&nbsp;dict )
</h3>
<p> Constructs a copy of <em>dict</em>.
<p> Each item in <em>dict</em> is inserted into this dictionary. Only the
pointers are copied (shallow copy).
<h3 class=fn><a name="~TQPtrDict"></a>TQPtrDict::~TQPtrDict ()
</h3>
<p> Removes all items from the dictionary and destroys it.
<p> All iterators that access this dictionary will be reset.
<p> <p>See also <a href="ntqptrcollection.html#setAutoDelete">setAutoDelete</a>().
<h3 class=fn>bool <a name="autoDelete"></a>TQPtrCollection::autoDelete () const
</h3>
<p> Returns the setting of the auto-delete option. The default is FALSE.
<p> <p>See also <a href="ntqptrcollection.html#setAutoDelete">setAutoDelete</a>().
<h3 class=fn>void <a name="clear"></a>TQPtrDict::clear ()<tt> [virtual]</tt>
</h3>
<p> Removes all items from the dictionary.
<p> The removed items are deleted if <a href="ntqptrcollection.html#setAutoDelete">auto-deletion</a> is enabled.
<p> All dictionary iterators that access this dictionary will be
reset.
<p> <p>See also <a href="#remove">remove</a>(), <a href="#take">take</a>(), and <a href="ntqptrcollection.html#setAutoDelete">setAutoDelete</a>().
<p>Reimplemented from <a href="ntqptrcollection.html#clear">TQPtrCollection</a>.
<h3 class=fn>uint <a name="count"></a>TQPtrDict::count () const<tt> [virtual]</tt>
</h3>
<p> Returns the number of items in the dictionary.
<p> <p>See also <a href="#isEmpty">isEmpty</a>().
<p>Reimplemented from <a href="ntqptrcollection.html#count">TQPtrCollection</a>.
<h3 class=fn>type * <a name="find"></a>TQPtrDict::find ( void&nbsp;*&nbsp;key ) const
</h3>
<p> Returns the item associated with <em>key</em>, or 0 if the key does not
exist in the dictionary.
<p> If there are two or more items with equal keys, then the most
recently inserted item will be found.
<p> Equivalent to operator[].
<p> <p>See also <a href="#operator[]">operator[]</a>().
<h3 class=fn>void <a name="insert"></a>TQPtrDict::insert ( void&nbsp;*&nbsp;key, const&nbsp;type&nbsp;*&nbsp;item )
</h3>
<p> Inserts the <em>key</em> with the <em>item</em> into the dictionary.
<p> Multiple items can have the same key, in which case only the last
item will be accessible using <a href="#operator[]">operator[]</a>().
<p> <em>item</em> may not be 0.
<p> <p>See also <a href="#replace">replace</a>().
<h3 class=fn>bool <a name="isEmpty"></a>TQPtrDict::isEmpty () const
</h3>
<p> Returns TRUE if the dictionary is empty; otherwise returns FALSE.
<p> <p>See also <a href="#count">count</a>().
<h3 class=fn><a href="ntqptrdict.html">TQPtrDict</a>&lt;type&gt;&nbsp;&amp; <a name="operator-eq"></a>TQPtrDict::operator= ( const&nbsp;<a href="ntqptrdict.html">TQPtrDict</a>&lt;type&gt;&nbsp;&amp;&nbsp;dict )
</h3>
<p> Assigns <em>dict</em> to this dictionary and returns a reference to this
dictionary.
<p> This dictionary is first cleared and then each item in <em>dict</em> is
inserted into the dictionary. Only the pointers are copied
(shallow copy), unless <a href="ntqptrcollection.html#newItem">newItem</a>() has been reimplemented.
<h3 class=fn>type * <a name="operator[]"></a>TQPtrDict::operator[] ( void&nbsp;*&nbsp;key ) const
</h3>
<p> Returns the item associated with <em>key</em>, or 0 if the key does not
exist in the dictionary.
<p> If there are two or more items with equal keys, then the most
recently inserted item will be found.
<p> Equivalent to the <a href="#find">find</a>() function.
<p> <p>See also <a href="#find">find</a>().
<h3 class=fn><a href="ntqdatastream.html">TQDataStream</a>&nbsp;&amp; <a name="read"></a>TQPtrDict::read ( <a href="ntqdatastream.html">TQDataStream</a>&nbsp;&amp;&nbsp;s, <a href="ntqptrcollection.html#Item">TQPtrCollection::Item</a>&nbsp;&amp;&nbsp;item )<tt> [virtual protected]</tt>
</h3>
<p> Reads a dictionary item from the stream <em>s</em> and returns a
reference to the stream.
<p> The default implementation sets <em>item</em> to 0.
<p> <p>See also <a href="#write">write</a>().
<h3 class=fn>bool <a name="remove"></a>TQPtrDict::remove ( void&nbsp;*&nbsp;key )
</h3>
<p> Removes the item associated with <em>key</em> from the dictionary.
Returns TRUE if successful, i.e. if <em>key</em> is in the dictionary;
otherwise returns FALSE.
<p> If there are two or more items with equal keys, then the most
recently inserted item will be removed.
<p> The removed item is deleted if <a href="ntqptrcollection.html#setAutoDelete">auto-deletion</a> is enabled.
<p> All dictionary iterators that refer to the removed item will be
set to point to the next item in the dictionary traversal order.
<p> <p>See also <a href="#take">take</a>(), <a href="#clear">clear</a>(), and <a href="ntqptrcollection.html#setAutoDelete">setAutoDelete</a>().
<h3 class=fn>void <a name="replace"></a>TQPtrDict::replace ( void&nbsp;*&nbsp;key, const&nbsp;type&nbsp;*&nbsp;item )
</h3>
<p> If the dictionary has key <em>key</em>, this key's item is replaced with
<em>item</em>. If the dictionary doesn't contain key <em>key</em>, <em>item</em> is
inserted into the dictionary using key <em>key</em>.
<p> <em>item</em> may not be 0.
<p> Equivalent to
<pre>
TQPtrDict&lt;ItemType&gt; dict;
...
if ( dict.<a href="#find">find</a>( key ) )
dict.<a href="#remove">remove</a>( key );
dict.<a href="#insert">insert</a>( key, item );
</pre>
<p> If there are two or more items with equal keys, then the most
recently inserted item will be replaced.
<p> <p>See also <a href="#insert">insert</a>().
<h3 class=fn>void <a name="resize"></a>TQPtrDict::resize ( uint&nbsp;newsize )
</h3>
<p> Changes the size of the hash table to <em>newsize</em>. The contents of
the dictionary are preserved, but all iterators on the dictionary
become invalid.
<h3 class=fn>void <a name="setAutoDelete"></a>TQPtrCollection::setAutoDelete ( bool&nbsp;enable )
</h3>
<p> Sets the collection to auto-delete its contents if <em>enable</em> is
TRUE and to never delete them if <em>enable</em> is FALSE.
<p> If auto-deleting is turned on, all the items in a collection are
deleted when the collection itself is deleted. This is convenient
if the collection has the only pointer to the items.
<p> The default setting is FALSE, for safety. If you turn it on, be
careful about copying the collection - you might find yourself
with two collections deleting the same items.
<p> Note that the auto-delete setting may also affect other functions
in subclasses. For example, a subclass that has a <a href="#remove">remove</a>()
function will remove the item from its data structure, and if
auto-delete is enabled, will also delete the item.
<p> <p>See also <a href="ntqptrcollection.html#autoDelete">autoDelete</a>().
<p>Examples: <a href="grapher-nsplugin-example.html#x2769">grapher/grapher.cpp</a>, <a href="scribble-example.html#x924">scribble/scribble.cpp</a>, and <a href="bigtable-example.html#x1291">table/bigtable/main.cpp</a>.
<h3 class=fn>uint <a name="size"></a>TQPtrDict::size () const
</h3>
<p> Returns the size of the internal hash table (as specified in the
constructor).
<p> <p>See also <a href="#count">count</a>().
<h3 class=fn>void <a name="statistics"></a>TQPtrDict::statistics () const
</h3>
<p> Debugging-only function that prints out the dictionary
distribution using <a href="ntqapplication.html#qDebug">qDebug</a>().
<h3 class=fn>type * <a name="take"></a>TQPtrDict::take ( void&nbsp;*&nbsp;key )
</h3>
<p> Takes the item associated with <em>key</em> out of the dictionary
without deleting it (even if <a href="ntqptrcollection.html#setAutoDelete">auto-deletion</a> is enabled).
<p> If there are two or more items with equal keys, then the most
recently inserted item will be removed.
<p> Returns a pointer to the item taken out, or 0 if the key does not
exist in the dictionary.
<p> All dictionary iterators that refer to the taken item will be set
to point to the next item in the dictionary traversal order.
<p> <p>See also <a href="#remove">remove</a>(), <a href="#clear">clear</a>(), and <a href="ntqptrcollection.html#setAutoDelete">setAutoDelete</a>().
<h3 class=fn><a href="ntqdatastream.html">TQDataStream</a>&nbsp;&amp; <a name="write"></a>TQPtrDict::write ( <a href="ntqdatastream.html">TQDataStream</a>&nbsp;&amp;&nbsp;s, <a href="ntqptrcollection.html#Item">TQPtrCollection::Item</a> ) const<tt> [virtual protected]</tt>
</h3>
<p> Writes a dictionary item to the stream <em>s</em> and returns a
reference to the stream.
<p> <p>See also <a href="#read">read</a>().
<!-- eof -->
<hr><p>
This file is part of the <a href="index.html">TQt toolkit</a>.
Copyright &copy; 1995-2007
<a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center>
<table width=100% cellspacing=0 border=0><tr>
<td>Copyright &copy; 2007
<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a>
<td align=right><div align=right>TQt 3.3.8</div>
</table></div></address></body>
</html>