/**************************************************************************** ** ** 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 requirements 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\ 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 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 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 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 &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 &QDict::operator=(const QDict &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 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\ to create a dictionary iterator that operates on QDict\ (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 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 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 &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. */