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| author | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
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| committer | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
| commit | bd0f3345a938b35ce6a12f6150373b0955b8dd12 (patch) | |
| tree | 7a520322212d48ebcb9fbe1087e7fca28b76185c /doc/html/qdict.html | |
| download | qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.tar.gz qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.zip | |
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diff --git a/doc/html/qdict.html b/doc/html/qdict.html new file mode 100644 index 0000000..04c3047 --- /dev/null +++ b/doc/html/qdict.html @@ -0,0 +1,399 @@ +<!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/qdict.doc:41 --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>QDict 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 Classes</font></a> + | <a href="mainclasses.html"> +<font color="#004faf">Main Classes</font></a> + | <a href="annotated.html"> +<font color="#004faf">Annotated</font></a> + | <a href="groups.html"> +<font color="#004faf">Grouped 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>QDict Class Reference</h1> + +<p>The QDict class is a template class that provides a +dictionary based on QString keys. +<a href="#details">More...</a> +<p><tt>#include <<a href="qdict-h.html">qdict.h</a>></tt> +<p>Inherits <a href="qptrcollection.html">QPtrCollection</a>. +<p><a href="qdict-members.html">List of all member functions.</a> +<h2>Public Members</h2> +<ul> +<li class=fn><a href="#QDict"><b>QDict</b></a> ( int size = 17, bool caseSensitive = TRUE )</li> +<li class=fn><a href="#QDict-2"><b>QDict</b></a> ( const QDict<type> & dict )</li> +<li class=fn><a href="#~QDict"><b>~QDict</b></a> ()</li> +<li class=fn>QDict<type> & <a href="#operator-eq"><b>operator=</b></a> ( const QDict<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> ( const QString & key, const type * item )</li> +<li class=fn>void <a href="#replace"><b>replace</b></a> ( const QString & key, const type * item )</li> +<li class=fn>bool <a href="#remove"><b>remove</b></a> ( const QString & key )</li> +<li class=fn>type * <a href="#take"><b>take</b></a> ( const QString & key )</li> +<li class=fn>type * <a href="#find"><b>find</b></a> ( const QString & key ) const</li> +<li class=fn>type * <a href="#operator[]"><b>operator[]</b></a> ( const QString & 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 QDict class is a template class that provides a +dictionary based on <a href="qstring.html">QString</a> keys. +<p> + + +<p> +<p> <a href="qmap.html">QMap</a> is an STL-compatible alternative to this class. +<p> QDict is implemented as a template class. Define a template +instance QDict<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 +QString used for insertion, removal and lookup. The value is a +pointer. Dictionaries provide very fast insertion and lookup. +<p> If you want to use non-Unicode, plain 8-bit <tt>char*</tt> keys, use the +<a href="qasciidict.html">QAsciiDict</a> template. A QDict has the same performance as a +QAsciiDict. If you want to have a dictionary that maps QStrings to +QStrings use QMap. +<p> The <a href="#size">size</a>() of the dictionary is very important. In order to get +good performance, you should use a suitably large <a href="primes.html#prime">prime</a> number. +Suitable means equal to or larger than the maximum expected number +of dictionary items. Size is set in the constructor but may be +changed with <a href="#resize">resize</a>(). +<p> Items are inserted with <a href="#insert">insert</a>(); 0 pointers cannot be inserted. +Items are removed with <a href="#remove">remove</a>(). All the items in a dictionary can +be removed with <a href="#clear">clear</a>(). The number of items in the dictionary is +returned by <a href="#count">count</a>(). If the dictionary contains no items <a href="#isEmpty">isEmpty</a>() +returns TRUE. You can change an item's value with <a href="#replace">replace</a>(). Items +are looked up with <a href="#operator[]">operator[]</a>(), or with <a href="#find">find</a>() which return a +pointer to the value or 0 if the given key does not exist. You can +take an item out of the dictionary with <a href="#take">take</a>(). +<p> Calling <a href="qptrcollection.html#setAutoDelete">setAutoDelete</a>(TRUE) for a dictionary tells it to delete +items that are removed. The default behaviour is not to delete +items when they are removed. +<p> When an item is inserted, the key is converted (hashed) to an +integer index into an internal hash array. This makes lookup very +fast. +<p> Items with equal keys are allowed. When inserting two items with +the same key, only the last inserted item will be accessible (last +in, first out) until it is removed. +<p> The <a href="qdictiterator.html">QDictIterator</a> class can traverse the dictionary, but only in +an arbitrary order. Multiple iterators may independently traverse +the same dictionary. +<p> When inserting an item into a dictionary, only the pointer is +copied, not the item itself, i.e. a <a href="shclass.html#shallow-copy">shallow copy</a> is made. It is +possible to make the dictionary copy all of the item's data (a +<a href="shclass.html#deep-copy">deep copy</a>) when an item is inserted. <a href="#insert">insert</a>() calls the virtual +function <a href="qptrcollection.html#newItem">QPtrCollection::newItem</a>() for the item to be inserted. +Inherit a dictionary and reimplement <a href="qptrcollection.html#newItem">newItem</a>() if you want deep +copies. +<p> When removing a dictionary item, the virtual function +<a href="qptrcollection.html#deleteItem">QPtrCollection::deleteItem</a>() is called. QDict's default +implementation is to delete the item if auto-deletion is enabled. +<p> Example #1: +<pre> + QDict<QLineEdit> fields; // QString keys, QLineEdit* values + fields.<a href="#insert">insert</a>( "forename", new <a href="qlineedit.html">QLineEdit</a>( this ) ); + fields.<a href="#insert">insert</a>( "surname", new <a href="qlineedit.html">QLineEdit</a>( this ) ); + + fields["forename"]->setText( "Homer" ); + fields["surname"]->setText( "Simpson" ); + + <a href="qdictiterator.html">QDictIterator</a><QLineEdit> it( fields ); // See QDictIterator + for( ; it.<a href="qdictiterator.html#current">current</a>(); ++it ) + cout << it.<a href="qdictiterator.html#currentKey">currentKey</a>() << ": " << it.<a href="qdictiterator.html#current">current</a>()->text() << endl; + cout << endl; + + if ( fields["forename"] && fields["surname"] ) + cout << fields["forename"]->text() << " " + << fields["surname"]->text() << endl; // Prints "Homer Simpson" + + fields.<a href="#remove">remove</a>( "forename" ); // Does not delete the line edit + if ( ! fields["forename"] ) + cout << "forename is not in the dictionary" << endl; + </pre> + +In this example we use a dictionary to keep track of the line +edits we're using. We insert each line edit into the dictionary +with a unique name and then access the line edits via the +dictionary. +<p> Example #2: +<pre> + <a href="qstringlist.html">QStringList</a> styleList = QStyleFactory::styles(); + styleList.<a href="qstringlist.html#sort">sort</a>(); + QDict<int> letterDict( 17, FALSE ); + for ( QStringList::Iterator it = styleList.<a href="qvaluelist.html#begin">begin</a>(); it != styleList.<a href="qvaluelist.html#end">end</a>(); ++it ) { + <a href="qstring.html">QString</a> styleName = *it; + <a href="qstring.html">QString</a> styleAccel = styleName; + if ( letterDict[styleAccel.<a href="qstring.html#left">left</a>(1)] ) { + for ( uint i = 0; i < styleAccel.<a href="qstring.html#length">length</a>(); i++ ) { + if ( ! letterDict[styleAccel.<a href="qstring.html#mid">mid</a>( i, 1 )] ) { + styleAccel = styleAccel.<a href="qstring.html#insert">insert</a>( i, '&' ); + letterDict.<a href="#insert">insert</a>(styleAccel.<a href="qstring.html#mid">mid</a>( i, 1 ), (const int *)1); + break; + } + } + } else { + styleAccel = "&" + styleAccel; + letterDict.<a href="#insert">insert</a>(styleAccel.<a href="qstring.html#left">left</a>(1), (const int *)1); + } + (void) new <a href="qaction.html">QAction</a>( styleName, QIconSet(), styleAccel, parent ); + } + </pre> + +In the example we are using the dictionary to provide fast random +access to the keys, and we don't care what the values are. The +example is used to generate a menu of QStyles, each with a unique +accelerator key (or no accelerator if there are no unused letters +left). +<p> We first obtain the list of available styles, then sort them so +that the menu items will be ordered alphabetically. Next we create +a dictionary of int pointers. The keys in the dictionary are each +one character long, representing letters that have been used for +accelerators. We iterate through our list of style names. If the +first letter of the style name is in the dictionary, i.e. has been +used, we iterate over all the characters in the style name to see +if we can find a letter that hasn't been used. If we find an +unused letter we put the accelerator ampersand (&) in front of it +and add that letter to the dictionary. If we can't find an unused +letter the style will simply have no accelerator. If the first +letter of the style name is not in the dictionary we use it for +the accelerator and add it to the dictionary. Finally we create a +<a href="qaction.html">QAction</a> for each style. +<p> <p>See also <a href="qdictiterator.html">QDictIterator</a>, <a href="qasciidict.html">QAsciiDict</a>, <a href="qintdict.html">QIntDict</a>, <a href="qptrdict.html">QPtrDict</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="QDict"></a>QDict::QDict ( int size = 17, bool caseSensitive = TRUE ) +</h3> + +<p> Constructs a dictionary optimized for less than <em>size</em> entries. +<p> We recommend setting <em>size</em> to a suitably large <a href="primes.html#prime">prime</a> number +(e.g. a prime that's slightly larger than the expected number of +entries). This makes the hash distribution better which will lead +to faster lookup. +<p> If <em>caseSensitive</em> is TRUE (the default), keys which differ only +by case are considered different. + +<h3 class=fn><a name="QDict-2"></a>QDict::QDict ( const <a href="qdict.html">QDict</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="~QDict"></a>QDict::~QDict () +</h3> + +<p> Removes all items from the dictionary and destroys it. If +<a href="qptrcollection.html#setAutoDelete">setAutoDelete</a>() is TRUE, each value is deleted. 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>QDict::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 operate on the dictionary are 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>QDict::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>QDict::find ( const <a href="qstring.html">QString</a> & key ) const +</h3> + +<p> Returns the item with key <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 [] operator. +<p> <p>See also <a href="#operator[]">operator[]</a>(). + +<h3 class=fn>void <a name="insert"></a>QDict::insert ( const <a href="qstring.html">QString</a> & key, const type * item ) +</h3> + +<p> Inserts the key <em>key</em> with value <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>(). + +<p>Example: <a href="themes-example.html#x326">themes/themes.cpp</a>. +<h3 class=fn>bool <a name="isEmpty"></a>QDict::isEmpty () const +</h3> + +<p> Returns TRUE if the dictionary is empty, i.e. <a href="#count">count</a>() == 0; +otherwise returns FALSE. +<p> <p>See also <a href="#count">count</a>(). + +<h3 class=fn><a href="qdict.html">QDict</a><type> & <a name="operator-eq"></a>QDict::operator= ( const <a href="qdict.html">QDict</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, then each item in <em>dict</em> is +inserted into this 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>QDict::operator[] ( const <a href="qstring.html">QString</a> & key ) const +</h3> + +<p> Returns the item with key <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>QDict::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>QDict::remove ( const <a href="qstring.html">QString</a> & key ) +</h3> + +<p> Removes the item with <em>key</em> from the dictionary. Returns TRUE if +successful, i.e. if the item is in the dictionary; otherwise +returns FALSE. +<p> If there are two or more items with equal keys, then the last item +that was inserted 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's 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>QDict::replace ( const <a href="qstring.html">QString</a> & key, const type * item ) +</h3> + +<p> Replaces the value of the key, <em>key</em> with <em>item</em>. +<p> If the item does not already exist, it will be inserted. +<p> <em>item</em> may not be 0. +<p> Equivalent to: +<pre> + QDict<char> 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 last item +that was inserted will be replaced. +<p> <p>See also <a href="#insert">insert</a>(). + +<h3 class=fn>void <a name="resize"></a>QDict::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>QDict::size () const +</h3> + +<p> Returns the size of the internal hash array (as specified in the +constructor). +<p> <p>See also <a href="#count">count</a>(). + +<h3 class=fn>void <a name="statistics"></a>QDict::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>QDict::take ( const <a href="qstring.html">QString</a> & key ) +</h3> + +<p> Takes the item 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 last item +that was inserted will be taken. +<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>QDict::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>(). + +<!-- eof --> +<hr><p> +This file is part of the <a href="index.html">Qt toolkit</a>. +Copyright © 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 © 2007 +<a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> +<td align=right><div align=right>Qt 3.3.8</div> +</table></div></address></body> +</html> |