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authorTimothy Pearson <kb9vqf@pearsoncomputing.net>2011-11-08 12:31:36 -0600
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+/****************************************************************************
+**
+** QDict and QDictIterator class documentation
+**
+** Copyright (C) 1992-2008 Trolltech ASA. All rights reserved.
+**
+** This file is part of the Qt GUI Toolkit.
+**
+** This file may be used under the terms of the GNU General
+** Public License versions 2.0 or 3.0 as published by the Free
+** Software Foundation and appearing in the files LICENSE.GPL2
+** and LICENSE.GPL3 included in the packaging of this file.
+** Alternatively you may (at your option) use any later version
+** of the GNU General Public License if such license has been
+** publicly approved by Trolltech ASA (or its successors, if any)
+** and the KDE Free Qt Foundation.
+**
+** Please review the following information to ensure GNU General
+** Public Licensing retquirements will be met:
+** http://trolltech.com/products/qt/licenses/licensing/opensource/.
+** If you are unsure which license is appropriate for your use, please
+** review the following information:
+** http://trolltech.com/products/qt/licenses/licensing/licensingoverview
+** or contact the sales department at sales@trolltech.com.
+**
+** This file may be used under the terms of the Q Public License as
+** defined by Trolltech ASA and appearing in the file LICENSE.QPL
+** included in the packaging of this file. Licensees holding valid Qt
+** Commercial licenses may use this file in accordance with the Qt
+** Commercial License Agreement provided with the Software.
+**
+** This file is provided "AS IS" with NO WARRANTY OF ANY KIND,
+** INCLUDING THE WARRANTIES OF DESIGN, MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE. Trolltech reserves all rights not granted
+** herein.
+**
+**********************************************************************/
+
+
+/*****************************************************************************
+ QDict documentation
+ *****************************************************************************/
+
+/*!
+ \class QDict
+ \brief The QDict class is a template class that provides a
+ dictionary based on QString keys.
+
+ \ingroup collection
+ \ingroup tools
+ \mainclass
+
+ \important autoDelete setAutoDelete
+
+ QMap is an STL-compatible alternative to this class.
+
+ QDict is implemented as a template class. Define a template
+ instance QDict\<X\> to create a dictionary that operates on
+ pointers to X (X *).
+
+ 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.
+
+ If you want to use non-Unicode, plain 8-bit \c char* keys, use the
+ QAsciiDict template. A QDict has the same performance as a
+ QAsciiDict. If you want to have a dictionary that maps QStrings to
+ QStrings use QMap.
+
+ The size() of the dictionary is very important. In order to get
+ good performance, you should use a suitably large prime 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 resize().
+
+ Items are inserted with insert(); 0 pointers cannot be inserted.
+ Items are removed with remove(). All the items in a dictionary can
+ be removed with clear(). The number of items in the dictionary is
+ returned by count(). If the dictionary contains no items isEmpty()
+ returns TRUE. You can change an item's value with replace(). Items
+ are looked up with operator[](), or with find() 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 take().
+
+ Calling setAutoDelete(TRUE) for a dictionary tells it to delete
+ items that are removed. The default behaviour is not to delete
+ items when they are removed.
+
+ When an item is inserted, the key is converted (hashed) to an
+ integer index into an internal hash array. This makes lookup very
+ fast.
+
+ 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.
+
+ The QDictIterator class can traverse the dictionary, but only in
+ an arbitrary order. Multiple iterators may independently traverse
+ the same dictionary.
+
+ When inserting an item into a dictionary, only the pointer is
+ copied, not the item itself, i.e. a shallow copy is made. It is
+ possible to make the dictionary copy all of the item's data (a
+ deep copy) when an item is inserted. insert() calls the virtual
+ function QPtrCollection::newItem() for the item to be inserted.
+ Inherit a dictionary and reimplement newItem() if you want deep
+ copies.
+
+ When removing a dictionary item, the virtual function
+ QPtrCollection::deleteItem() is called. QDict's default
+ implementation is to delete the item if auto-deletion is enabled.
+
+ Example #1:
+ \code
+ QDict<QLineEdit> fields; // QString keys, QLineEdit* values
+ fields.insert( "forename", new QLineEdit( this ) );
+ fields.insert( "surname", new QLineEdit( this ) );
+
+ fields["forename"]->setText( "Homer" );
+ fields["surname"]->setText( "Simpson" );
+
+ QDictIterator<QLineEdit> it( fields ); // See QDictIterator
+ for( ; it.current(); ++it )
+ cout << it.currentKey() << ": " << it.current()->text() << endl;
+ cout << endl;
+
+ if ( fields["forename"] && fields["surname"] )
+ cout << fields["forename"]->text() << " "
+ << fields["surname"]->text() << endl; // Prints "Homer Simpson"
+
+ fields.remove( "forename" ); // Does not delete the line edit
+ if ( ! fields["forename"] )
+ cout << "forename is not in the dictionary" << endl;
+ \endcode
+ 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.
+
+ Example #2:
+ \code
+ QStringList styleList = QStyleFactory::styles();
+ styleList.sort();
+ QDict<int> letterDict( 17, FALSE );
+ for ( QStringList::Iterator it = styleList.begin(); it != styleList.end(); ++it ) {
+ QString styleName = *it;
+ QString styleAccel = styleName;
+ if ( letterDict[styleAccel.left(1)] ) {
+ for ( uint i = 0; i < styleAccel.length(); i++ ) {
+ if ( ! letterDict[styleAccel.mid( i, 1 )] ) {
+ styleAccel = styleAccel.insert( i, '&' );
+ letterDict.insert(styleAccel.mid( i, 1 ), (const int *)1);
+ break;
+ }
+ }
+ } else {
+ styleAccel = "&" + styleAccel;
+ letterDict.insert(styleAccel.left(1), (const int *)1);
+ }
+ (void) new QAction( styleName, QIconSet(), styleAccel, parent );
+ }
+ \endcode
+ 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).
+
+ 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
+ QAction for each style.
+
+ \sa QDictIterator, QAsciiDict, QIntDict, QPtrDict
+*/
+
+
+/*!
+ \fn QDict::QDict( int size, bool caseSensitive )
+
+ Constructs a dictionary optimized for less than \a size entries.
+
+ We recommend setting \a size to a suitably large prime 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.
+
+ If \a caseSensitive is TRUE (the default), keys which differ only
+ by case are considered different.
+*/
+
+/*!
+ \fn QDict::QDict( const QDict<type> &dict )
+
+ Constructs a copy of \a dict.
+
+ Each item in \a dict is inserted into this dictionary. Only the
+ pointers are copied (shallow copy).
+*/
+
+/*!
+ \fn QDict::~QDict()
+
+ Removes all items from the dictionary and destroys it. If
+ setAutoDelete() is TRUE, each value is deleted. All iterators that
+ access this dictionary will be reset.
+
+ \sa setAutoDelete()
+*/
+
+/*!
+ \fn QDict<type> &QDict::operator=(const QDict<type> &dict)
+
+ Assigns \a dict to this dictionary and returns a reference to this
+ dictionary.
+
+ This dictionary is first cleared, then each item in \a dict is
+ inserted into this dictionary. Only the pointers are copied
+ (shallow copy), unless newItem() has been reimplemented.
+*/
+
+/*!
+ \fn uint QDict::count() const
+
+ Returns the number of items in the dictionary.
+
+ \sa isEmpty()
+*/
+
+/*!
+ \fn uint QDict::size() const
+
+ Returns the size of the internal hash array (as specified in the
+ constructor).
+
+ \sa count()
+*/
+
+/*!
+ \fn void QDict::resize( uint newsize )
+
+ Changes the size of the hash table to \a newsize. The contents of
+ the dictionary are preserved, but all iterators on the dictionary
+ become invalid.
+*/
+
+/*!
+ \fn bool QDict::isEmpty() const
+
+ Returns TRUE if the dictionary is empty, i.e. count() == 0;
+ otherwise returns FALSE.
+
+ \sa count()
+*/
+
+/*!
+ \fn void QDict::insert( const QString &key, const type *item )
+
+ Inserts the key \a key with value \a item into the dictionary.
+
+ Multiple items can have the same key, in which case only the last
+ item will be accessible using \l operator[]().
+
+ \a item may not be 0.
+
+ \sa replace()
+*/
+
+/*!
+ \fn void QDict::replace( const QString &key, const type *item )
+
+ Replaces the value of the key, \a key with \a item.
+
+ If the item does not already exist, it will be inserted.
+
+ \a item may not be 0.
+
+ Equivalent to:
+ \code
+ QDict<char> dict;
+ ...
+ if ( dict.find( key ) )
+ dict.remove( key );
+ dict.insert( key, item );
+ \endcode
+
+ If there are two or more items with equal keys, then the last item
+ that was inserted will be replaced.
+
+ \sa insert()
+*/
+
+/*!
+ \fn bool QDict::remove( const QString &key )
+
+ Removes the item with \a key from the dictionary. Returns TRUE if
+ successful, i.e. if the item is in the dictionary; otherwise
+ returns FALSE.
+
+ If there are two or more items with equal keys, then the last item
+ that was inserted will be removed.
+
+ The removed item is deleted if \link
+ QPtrCollection::setAutoDelete() auto-deletion\endlink is enabled.
+
+ All dictionary iterators that refer to the removed item will be
+ set to point to the next item in the dictionary's traversal order.
+
+ \sa take(), clear(), setAutoDelete()
+*/
+
+/*!
+ \fn type *QDict::take( const QString &key )
+
+ Takes the item with \a key out of the dictionary without deleting
+ it (even if \link QPtrCollection::setAutoDelete()
+ auto-deletion\endlink is enabled).
+
+ If there are two or more items with equal keys, then the last item
+ that was inserted will be taken.
+
+ Returns a pointer to the item taken out, or 0 if the key does not
+ exist in the dictionary.
+
+ All dictionary iterators that refer to the taken item will be set
+ to point to the next item in the dictionary traversal order.
+
+ \sa remove(), clear(), setAutoDelete()
+*/
+
+/*!
+ \fn void QDict::clear()
+
+ Removes all items from the dictionary.
+
+ The removed items are deleted if \link
+ QPtrCollection::setAutoDelete() auto-deletion\endlink is enabled.
+
+ All dictionary iterators that operate on the dictionary are reset.
+
+ \sa remove(), take(), setAutoDelete()
+*/
+
+/*!
+ \fn type *QDict::find( const QString &key ) const
+
+ Returns the item with key \a key, or 0 if the key does not exist
+ in the dictionary.
+
+ If there are two or more items with equal keys, then the most
+ recently inserted item will be found.
+
+ Equivalent to the [] operator.
+
+ \sa operator[]()
+*/
+
+/*!
+ \fn type *QDict::operator[]( const QString &key ) const
+
+ Returns the item with key \a key, or 0 if the key does not
+ exist in the dictionary.
+
+ If there are two or more items with equal keys, then the most
+ recently inserted item will be found.
+
+ Equivalent to the find() function.
+
+ \sa find()
+*/
+
+/*!
+ \fn void QDict::statistics() const
+
+ Debugging-only function that prints out the dictionary
+ distribution using qDebug().
+*/
+
+/*!
+ \fn QDataStream& QDict::read( QDataStream &s, QPtrCollection::Item &item )
+
+ Reads a dictionary item from the stream \a s and returns a
+ reference to the stream.
+
+ The default implementation sets \a item to 0.
+
+ \sa write()
+*/
+
+/*!
+ \fn QDataStream& QDict::write( QDataStream &s, QPtrCollection::Item ) const
+
+ Writes a dictionary item to the stream \a s and returns a
+ reference to the stream.
+
+ \sa read()
+*/
+
+/*****************************************************************************
+ QDictIterator documentation
+ *****************************************************************************/
+
+/*!
+ \class QDictIterator qdict.h
+ \brief The QDictIterator class provides an iterator for QDict collections.
+
+ \ingroup collection
+ \ingroup tools
+
+ QDictIterator is implemented as a template class. Define a
+ template instance QDictIterator\<X\> to create a dictionary
+ iterator that operates on QDict\<X\> (dictionary of X*).
+
+ The traversal order is arbitrary; when we speak of the "first",
+ "last" and "next" item we are talking in terms of this arbitrary
+ order.
+
+ Multiple iterators may independently traverse the same dictionary.
+ A QDict knows about all the iterators that are operating on the
+ dictionary. When an item is removed from the dictionary, QDict
+ updates all iterators that are referring to the removed item to
+ point to the next item in the (arbitrary) traversal order.
+
+ Example:
+ \code
+ QDict<QLineEdit> fields;
+ fields.insert( "forename", new QLineEdit( this ) );
+ fields.insert( "surname", new QLineEdit( this ) );
+ fields.insert( "age", new QLineEdit( this ) );
+
+ fields["forename"]->setText( "Homer" );
+ fields["surname"]->setText( "Simpson" );
+ fields["age"]->setText( "45" );
+
+ QDictIterator<QLineEdit> it( fields );
+ for( ; it.current(); ++it )
+ cout << it.currentKey() << ": " << it.current()->text() << endl;
+ cout << endl;
+
+ // Output (random order):
+ // age: 45
+ // surname: Simpson
+ // forename: Homer
+ \endcode
+ In the example we insert some pointers to line edits into a
+ dictionary, then iterate over the dictionary printing the strings
+ associated with the line edits.
+
+ \sa QDict
+*/
+
+/*!
+ \fn QDictIterator::QDictIterator( const QDict<type> &dict )
+
+ Constructs an iterator for \a dict. The current iterator item is
+ set to point to the first item in the dictionary, \a dict. First
+ in this context means first in the arbitrary traversal order.
+*/
+
+/*!
+ \fn QDictIterator::~QDictIterator()
+
+ Destroys the iterator.
+*/
+
+/*!
+ \fn uint QDictIterator::count() const
+
+ Returns the number of items in the dictionary over which the
+ iterator is operating.
+
+ \sa isEmpty()
+*/
+
+/*!
+ \fn bool QDictIterator::isEmpty() const
+
+ Returns TRUE if the dictionary is empty, i.e. count() == 0;
+ otherwise returns FALSE.
+
+ \sa count()
+*/
+
+/*!
+ \fn type *QDictIterator::toFirst()
+
+ Resets the iterator, making the first item the first current item.
+ First in this context means first in the arbitrary traversal
+ order. Returns a pointer to this item.
+
+ If the dictionary is empty it sets the current item to 0 and
+ returns 0.
+*/
+
+/*!
+ \fn type *QDictIterator::operator*()
+ \internal
+*/
+
+/*!
+ \fn QDictIterator::operator type*() const
+
+ Cast operator. Returns a pointer to the current iterator item.
+ Same as current().
+*/
+
+
+/*!
+ \fn type *QDictIterator::current() const
+
+ Returns a pointer to the current iterator item's value.
+*/
+
+/*!
+ \fn QString QDictIterator::currentKey() const
+
+ Returns the current iterator item's key.
+*/
+
+/*!
+ \fn type *QDictIterator::operator()()
+
+ Makes the next item current and returns the original current item.
+
+ If the current iterator item was the last item in the dictionary
+ or if it was 0, 0 is returned.
+*/
+
+/*!
+ \fn type *QDictIterator::operator++()
+
+ Prefix ++ makes the next item current and returns the new current
+ item.
+
+ If the current iterator item was the last item in the dictionary
+ or if it was 0, 0 is returned.
+*/
+
+/*!
+ \fn type *QDictIterator::operator+=( uint jump )
+ \internal
+ Sets the current item to the item \a jump positions after the current item,
+ and returns a pointer to that item.
+
+ If that item is beyond the last item or if the dictionary is empty,
+ it sets the current item to 0 and returns 0.
+*/