/**************************************************************************** ** ** ** QIntDict and QIntDictIterator class documentation ** ** Copyright (C) 1992-2000 Trolltech AS. All rights reserved. ** ** This file is part of the Qt GUI Toolkit. ** ** This file may be distributed under the terms of the Q Public License ** as defined by Trolltech AS of Norway and appearing in the file ** LICENSE.QPL included in the packaging of this file. ** ** This file may be distributed and/or modified under the terms of the ** GNU General Public License version 2 as published by the Free Software ** Foundation and appearing in the file LICENSE.GPL included in the ** packaging of this file. ** ** Licensees holding valid Qt Enterprise Edition or Qt Professional Edition ** 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 ** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. ** ** See http://www.trolltech.com/pricing.html or email sales@trolltech.com for ** information about Qt Commercial License Agreements. ** See http://www.trolltech.com/qpl/ for QPL licensing information. ** See http://www.trolltech.com/gpl/ for GPL licensing information. ** ** Contact info@trolltech.com if any conditions of this licensing are ** not clear to you. ** **********************************************************************/ /***************************************************************************** QIntDict documentation *****************************************************************************/ /*! \class QIntDict qintdict.h \brief The QIntDict class is a template class that provides a dictionary based on \c long keys. \ingroup collection \ingroup tools QIntDict is implemented as a template class. Define a template instance QIntDict\ to create a dictionary that operates on pointers to X, or X*. A dictionary is a collection that associates an item with a key. The key is used for inserting and looking up an item. QIntDict has \c long keys. The dictionary has very fast insertion and lookup. Example: \code #include #include void main() { QIntDict dict; // maps long ==> char* dict.insert( 33, "France" ); dict.insert( 7, "Russia" ); dict.insert( 49, "Norway" ); printf( "%s\n", dict[49] ); printf( "%s\n", dict[33] ); printf( "%s\n", dict[7] ); if ( !dict[39] ) printf( "39 not defined\n" ); } \endcode Program output: \code Norway France Russia 39 not defined \endcode The dictionary in our example maps \c long keys to \c char* items. QIntDict implements the \link operator[] [] operator\endlink to lookup an item. QIntDict is implemented by QGDict as a hash array with a fixed number of entries. Each array entry points to a singly linked list of buckets, in which the dictionary items are stored. When an item is inserted with a key, the key is converted (hashed) to an integer index into the hash array using the \c mod operation. The item is inserted before the first bucket in the list of buckets. Looking up an item is normally very fast. The key is again hashed to an array index. Then QIntDict scans the list of buckets and returns the item found or null if the item was not found. You cannot insert null pointers into a dictionary. The size of the hash array is very important. In order to get good performance, you should use a suitably large \link primes.html prime number\endlink. Suitable means equal to or larger than the maximum expected number of dictionary items. Items with equal keys are allowed. When inserting two items with the same key, only the last inserted item will be visible (last in, first out) until it is removed. Example: \code #include #include void main() { QIntDict dict; // maps long ==> char* dict.insert( 7, "Russia" ); dict.insert( 7, "USSR" ); printf( "%s\n", dict[7] ); dict.remove( 7 ); // Gorbie was here printf( "%s\n", dict[7] ); } \endcode Program output: \code USSR Russia \endcode The QIntDictIterator class can traverse the dictionary contents, but only in an arbitrary order. Multiple iterators may independently traverse the same dictionary. Calling setAutoDelete(TRUE) for a dictionary tells it to delete items that are removed . The default is to not delete items when they are removed. When inserting an item into a dictionary, only the pointer is copied, not the item itself. This is called a shallow copy. It is possible to make the dictionary copy all of the item's data (known as a deep copy) when an item is inserted. insert() calls the virtual function QCollection::newItem() for the item to be inserted. Inherit a dictionary and reimplement it if you want deep copies. When removing a dictionary item, the virtual function QCollection::deleteItem() is called. QIntDict's default implementation is to delete the item if auto-deletion is enabled. \sa QIntDictIterator, QDict, QAsciiDict, QPtrDict, \link collection.html Collection Classes\endlink */ /*! \fn QIntDict::QIntDict( int size ) Constructs a dictionary using an internal hash array with the size \e size. Setting \e size to a suitably large \link primes.html prime number\endlink (equal to or greater than the expected number of entries) makes the hash distribution better and hence the loopup faster. */ /*! \fn QIntDict::QIntDict( const QIntDict &dict ) Constructs a copy of \e dict. Each item in \e dict are inserted into this dictionary. Only the pointers are copied (shallow copy). */ /*! \fn QIntDict::~QIntDict() Removes all items from the dictionary and destroys it. All iterators that access this dictionary will be reset. \sa setAutoDelete() */ /*! \fn QIntDict &QIntDict::operator=(const QIntDict &dict) Assigns \e dict to this dictionary and returns a reference to this dictionary. This dictionary is first cleared, then each item in \e dict is inserted into this dictionary. Only the pointers are copied (shallow copy), unless newItem() has been reimplemented. */ /*! \fn uint QIntDict::count() const Returns the number of items in the dictionary. \sa isEmpty() */ /*! \fn uint QIntDict::size() const Returns the size of the internal hash array (as specified in the constructor). \sa count() */ /*! \fn void QIntDict::resize( uint newsize ) Changes the size of the hashtable the \a newsize. The contents of the dictionary are preserved, but all iterators on the dictionary become invalid. */ /*! \fn bool QIntDict::isEmpty() const Returns TRUE if the dictionary is empty, i.e. count() == 0. Returns FALSE otherwise. \sa count() */ /*! \fn void QIntDict::insert( long key, const type *item ) Inserts the \e key with the \e item into the dictionary. The key does not have to be a unique dictionary key. If multiple items are inserted with the same key, only the last item will be visible. Null items are not allowed. \sa replace() */ /*! \fn void QIntDict::replace( long key, const type *item ) Replaces an item which has a key equal to \e key with \e item. If the item does not already exist, it will be inserted. Null items are not allowed. Equivalent to: \code QIntDict 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 inserted of these will be replaced. \sa insert() */ /*! \fn bool QIntDict::remove( long key ) Removes the item associated with \e key from the dictionary. Returns TRUE if successful, or FALSE if the key does not exist in the dictionary. If there are two or more items with equal keys, then the last inserted of these will be removed. The removed item is deleted if \link QCollection::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 traversing order. \sa take(), clear(), setAutoDelete() */ /*! \fn type *QIntDict::take( long key ) Takes the item associated with \e key out of the dictionary without deleting it (even if \link QCollection::setAutoDelete() auto-deletion\endlink is enabled). If there are two or more items with equal keys, then the last inserted of these will be taken. Returns a pointer to the item taken out, or null 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 traversing order. \sa remove(), clear(), setAutoDelete() */ /*! \fn void QIntDict::clear() Removes all items from the dictionary. The removed items are deleted if \link QCollection::setAutoDelete() auto-deletion\endlink is enabled. All dictionary iterators that access this dictionary will be reset. \sa remove(), take(), setAutoDelete() */ /*! \fn type *QIntDict::find( long key ) const Returns the item associated with \e key, or null if the key does not exist in the dictionary. This function uses an internal hashing algorithm to optimize lookup. If there are two or more items with equal keys, then the last inserted of these will be found. Equivalent to the [] operator. \sa operator[]() */ /*! \fn type *QIntDict::operator[]( long key ) const Returns the item associated with \e key, or null if the key does not exist in the dictionary. This function uses an internal hashing algorithm to optimize lookup. If there are two or more items with equal keys, then the last inserted of these will be found. Equivalent to the find() function. \sa find() */ /*! \fn void QIntDict::statistics() const Debugging-only function that prints out the dictionary distribution using qDebug(). */ /***************************************************************************** QIntDictIterator documentation *****************************************************************************/ /*! \class QIntDictIterator qintdict.h \brief The QIntDictIterator class provides an iterator for QIntDict collections. \ingroup collection \ingroup tools QIntDictIterator is implemented as a template class. Define a template instance QIntDictIterator\ to create a dictionary iterator that operates on QIntDict\ (dictionary of X*). Example: \code #include #include void main() { QIntDict dict; // maps long ==> char* dict.insert( 33, "France" ); dict.insert( 7, "Russia" ); dict.insert( 49, "Norway" ); QIntDictIterator it( dict ); // iterator for dict while ( it.current() ) { printf( "%d -> %s\n", it.currentKey(), it.current() ); ++it; } } \endcode Program output: \code 7 -> Russia 49 -> Norway 33 -> France \endcode Note that the traversal order is arbitrary, you are not guaranteed the order above. Multiple iterators may independently traverse the same dictionary. A QIntDict knows about all iterators that are operating on the dictionary. When an item is removed from the dictionary, QIntDict update all iterators that are referring the removed item to point to the next item in the traversing order. \sa QIntDict, \link collection.html Collection Classes\endlink */ /*! \fn QIntDictIterator::QIntDictIterator( const QIntDict &dict ) Constructs an iterator for \e dict. The current iterator item is set to point on the first item in the \e dict. */ /*! \fn QIntDictIterator::~QIntDictIterator() Destroys the iterator. */ /*! \fn uint QIntDictIterator::count() const Returns the number of items in the dictionary this iterator operates on. \sa isEmpty() */ /*! \fn bool QIntDictIterator::isEmpty() const Returns TRUE if the dictionary is empty, i.e. count() == 0. Returns FALSE otherwise. \sa count() */ /*! \fn type *QIntDictIterator::toFirst() Sets the current iterator item to point to the first item in the dictionary and returns a pointer to the item. If the dictionary is empty it sets the current item to null and returns null. */ /*! \fn QIntDictIterator::operator type *() const Cast operator. Returns a pointer to the current iterator item. Same as current(). */ /*! \fn type *QIntDictIterator::current() const Returns a pointer to the current iterator item. */ /*! \fn long QIntDictIterator::currentKey() const Returns the key for the current iterator item. */ /*! \fn type *QIntDictIterator::operator()() Makes the succeeding item current and returns the original current item. If the current iterator item was the last item in the dictionary or if it was null, null is returned. */ /*! \fn type *QIntDictIterator::operator++() Prefix ++ makes the succeeding item current and returns the new current item. If the current iterator item was the last item in the dictionary or if it was null, null is returned. */ /*! \fn type *QIntDictIterator::operator+=( uint jump ) Sets the current item to the item \e 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 null and returns null. */