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<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QPtrDict Class Reference</h1>
<p>The QPtrDict class is a template class that provides a dictionary based on void* keys.
<a href="#details">More...</a>
<p><tt>#include <<a href="qptrdict-h.html">qptrdict.h</a>></tt>
<p>Inherits <a href="qptrcollection.html">QPtrCollection</a>.
<p><a href="qptrdict-members.html">List of all member functions.</a>
<h2>Public Members</h2>
<ul>
<li class=fn><a href="#QPtrDict"><b>QPtrDict</b></a> ( int size = 17 )</li>
<li class=fn><a href="#QPtrDict-2"><b>QPtrDict</b></a> ( const QPtrDict<type> & dict )</li>
<li class=fn><a href="#~QPtrDict"><b>~QPtrDict</b></a> ()</li>
<li class=fn>QPtrDict<type> & <a href="#operator-eq"><b>operator=</b></a> ( const QPtrDict<type> & 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 * key, const type * item )</li>
<li class=fn>void <a href="#replace"><b>replace</b></a> ( void * key, const type * item )</li>
<li class=fn>bool <a href="#remove"><b>remove</b></a> ( void * key )</li>
<li class=fn>type * <a href="#take"><b>take</b></a> ( void * key )</li>
<li class=fn>type * <a href="#find"><b>find</b></a> ( void * key ) const</li>
<li class=fn>type * <a href="#operator[]"><b>operator[]</b></a> ( void * 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 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 enable )</li>
</ul>
<h2>Protected Members</h2>
<ul>
<li class=fn>virtual QDataStream & <a href="#read"><b>read</b></a> ( QDataStream & s, QPtrCollection::Item & item )</li>
<li class=fn>virtual QDataStream & <a href="#write"><b>write</b></a> ( QDataStream & s, QPtrCollection::Item ) const</li>
</ul>
<hr><a name="details"></a><h2>Detailed Description</h2>
The QPtrDict class is a template class that provides a dictionary based on void* keys.
<p>
<p>
<p> QPtrDict is implemented as a template class. Define a template
instance QPtrDict<X> 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>
QPtrDict<char> fields; // void* keys, char* values
<a href="qlineedit.html">QLineEdit</a> *le1 = new <a href="qlineedit.html">QLineEdit</a>( this );
le1-><a href="qlineedit.html#setText">setText</a>( "Simpson" );
<a href="qlineedit.html">QLineEdit</a> *le2 = new <a href="qlineedit.html">QLineEdit</a>( this );
le2-><a href="qlineedit.html#setText">setText</a>( "Homer" );
<a href="qlineedit.html">QLineEdit</a> *le3 = new <a href="qlineedit.html">QLineEdit</a>( this );
le3-><a href="qlineedit.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">QPtrDictIterator</a><char> it( fields );
for( ; it.<a href="qptrdictiterator.html#current">current</a>(); ++it )
cout << it.<a href="qptrdictiterator.html#current">current</a>() << endl;
cout << endl;
if ( fields[le1] ) // Prints "Surname: Simpson"
cout << fields[le1] << ": " << le1-><a href="qlineedit.html#text">text</a>() << endl;
if ( fields[le2] ) // Prints "Forename: Homer"
cout << fields[le2] << ": " << le2-><a href="qlineedit.html#text">text</a>() << endl;
fields.<a href="#remove">remove</a>( le1 ); // Removes le1 from the dictionary
cout << le1-><a href="qlineedit.html#text">text</a>() << 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="qdict.html">QDict</a> for full details, including the choice of dictionary
size, and how deletions are handled.
<p> <p>See also <a href="qptrdictiterator.html">QPtrDictIterator</a>, <a href="qdict.html">QDict</a>, <a href="qasciidict.html">QAsciiDict</a>, <a href="qintdict.html">QIntDict</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="QPtrDict"></a>QPtrDict::QPtrDict ( int 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="QPtrDict-2"></a>QPtrDict::QPtrDict ( const <a href="qptrdict.html">QPtrDict</a><type> & 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="~QPtrDict"></a>QPtrDict::~QPtrDict ()
</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="qptrcollection.html#setAutoDelete">setAutoDelete</a>().
<h3 class=fn>bool <a name="autoDelete"></a>QPtrCollection::autoDelete () const
</h3>
<p> Returns the setting of the auto-delete option. The default is FALSE.
<p> <p>See also <a href="qptrcollection.html#setAutoDelete">setAutoDelete</a>().
<h3 class=fn>void <a name="clear"></a>QPtrDict::clear ()<tt> [virtual]</tt>
</h3>
<p> Removes all items from the dictionary.
<p> The removed items are deleted if <a href="qptrcollection.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="qptrcollection.html#setAutoDelete">setAutoDelete</a>().
<p>Reimplemented from <a href="qptrcollection.html#clear">QPtrCollection</a>.
<h3 class=fn>uint <a name="count"></a>QPtrDict::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="qptrcollection.html#count">QPtrCollection</a>.
<h3 class=fn>type * <a name="find"></a>QPtrDict::find ( void * 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>QPtrDict::insert ( void * key, const type * 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>QPtrDict::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="qptrdict.html">QPtrDict</a><type> & <a name="operator-eq"></a>QPtrDict::operator= ( const <a href="qptrdict.html">QPtrDict</a><type> & 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="qptrcollection.html#newItem">newItem</a>() has been reimplemented.
<h3 class=fn>type * <a name="operator[]"></a>QPtrDict::operator[] ( void * 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="qdatastream.html">QDataStream</a> & <a name="read"></a>QPtrDict::read ( <a href="qdatastream.html">QDataStream</a> & s, <a href="qptrcollection.html#Item">QPtrCollection::Item</a> & 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>QPtrDict::remove ( void * 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="qptrcollection.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="qptrcollection.html#setAutoDelete">setAutoDelete</a>().
<h3 class=fn>void <a name="replace"></a>QPtrDict::replace ( void * key, const type * 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>
QPtrDict<ItemType> 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>QPtrDict::resize ( uint 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>QPtrCollection::setAutoDelete ( bool 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="qptrcollection.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>QPtrDict::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>QPtrDict::statistics () const
</h3>
<p> Debugging-only function that prints out the dictionary
distribution using <a href="qapplication.html#qDebug">qDebug</a>().
<h3 class=fn>type * <a name="take"></a>QPtrDict::take ( void * key )
</h3>
<p> Takes the item associated with <em>key</em> out of the dictionary
without deleting it (even if <a href="qptrcollection.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="qptrcollection.html#setAutoDelete">setAutoDelete</a>().
<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="write"></a>QPtrDict::write ( <a href="qdatastream.html">QDataStream</a> & s, <a href="qptrcollection.html#Item">QPtrCollection::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>().
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