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diff --git a/qtools/qdict.doc b/qtools/qdict.doc new file mode 100644 index 0000000..4472a3c --- /dev/null +++ b/qtools/qdict.doc @@ -0,0 +1,492 @@ +/**************************************************************************** +** $Id$ +** +** QDict and QDictIterator 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. +** +**********************************************************************/ + + +/***************************************************************************** + QDict documentation + *****************************************************************************/ + +/*! + \class QDict qdict.h + \brief The QDict class is a template class that provides a dictionary based on \c QString keys. + + \ingroup collection + \ingroup tools + + QDict is implemented as a template class. Define a template instance + QDict\<X\> 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. QDict has + \l QString keys, which are Unicode strings. If you want to use + non-Unicode, plain 8-bit \c char* keys, use the QAsciiDict template. + A QDict has the same performace as a QAsciiDict. + + The dictionary has very fast insertion and lookup. + + Example: + \code + #include <qdict.h> + #include <stdio.h> + + void main() + { + // Creates a dictionary that maps QString ==> char* (case insensitive) + QDict<char> dict( 17, FALSE ); + + dict.insert( "France", "Paris" ); + dict.insert( "Russia", "Moscow" ); + dict.insert( "Norway", "Oslo" ); + + printf( "%s\n", dict["Norway"] ); + printf( "%s\n", dict["FRANCE"] ); + printf( "%s\n", dict["russia"] ); + + if ( !dict["Italy"] ) + printf( "Italy not defined\n" ); + } + \endcode + + Program output: + \code + Oslo + Paris + Moscow + Italy not defined + \endcode + + The dictionary in our example maps \c QString keys to \c char* items. + Note that the mapping is case insensitive (specified in the + \link QDict::QDict() constructor\endlink). + QDict implements the \link operator[] [] operator\endlink to lookup an item. + + QDict 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. 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 QDict 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 <qdict.h> + #include <stdio.h> + + void main() + { + // Creates a dictionary that maps QString ==> char* (case sensitive) + QDict<char> dict; + + dict.insert( "Germany", "Berlin" ); + dict.insert( "Germany", "Bonn" ); + + printf( "%s\n", dict["Germany"] ); + dict.remove( "Germany" ); // Oct 3rd 1990 + printf( "%s\n", dict["Germany"] ); + } + \endcode + + Program output: + \code + Bonn + Berlin + \endcode + + The QDictIterator 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. QDict's default implementation + is to delete the item if auto-deletion is enabled. + + \sa QDictIterator, QAsciiDict, QIntDict, QPtrDict, + \link collection.html Collection Classes\endlink +*/ + + +/*! + \fn QDict::QDict( int size, bool caseSensitive ) + Constructs a dictionary with the following properties: + \arg \e size is the size of the internal hash array. + \arg \e caseSensitive specifies whether to use case sensitive lookup or not. + + 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. + + Setting \e caseSensitive to TRUE will treat "abc" and "Abc" as different + keys. Setting it to FALSE will make the dictionary ignore case. + Case insensitive comparison includes the whole Unicode alphabeth. +*/ + +/*! + \fn QDict::QDict( const QDict<type> &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 QDict::~QDict() + Removes all items from the dictionary and destroys it. + All iterators that access this dictionary will be reset. + + \sa setAutoDelete() +*/ + +/*! + \fn QDict<type> &QDict::operator=(const QDict<type> &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 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 hashtable the \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. Returns FALSE + otherwise. + \sa count() +*/ + +/*! + \fn void QDict::insert( const QString &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 QDict::replace( const QString &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 + 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 inserted + of these will be replaced. + + \sa insert() +*/ + +/*! + \fn bool QDict::remove( const QString &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 *QDict::take( const QString &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 traversal order. + + \sa remove(), clear(), setAutoDelete() +*/ + +/*! + \fn void QDict::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 operate on dictionary are reset. + + \sa remove(), take(), setAutoDelete() +*/ + +/*! + \fn type *QDict::find( const QString &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 *QDict::operator[]( const QString &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 QDict::statistics() const + Debugging-only function that prints out the dictionary distribution + using qDebug(). +*/ + + +/***************************************************************************** + 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*). + + Example: + \code + #include <qdict.h> + #include <stdio.h> + + void main() + { + // Creates a dictionary that maps QString ==> char* (case insensitive) + QDict<char> dict( 17, FALSE ); + + dict.insert( "France", "Paris" ); + dict.insert( "Russia", "Moscow" ); + dict.insert( "Norway", "Oslo" ); + + QDictIterator<char> it( dict ); // iterator for dict + + while ( it.current() ) { + printf( "%s -> %s\n", it.currentKey().latin1(), it.current() ); + ++it; + } + } + \endcode + + Program output: + \code + Russia -> Moscow + Norway -> Oslo + France -> Paris + \endcode + + Note that the traversal order is arbitrary, you are not guaranteed the + order above. + + Multiple iterators may independently traverse the same dictionary. + A QDict knows about all iterators that are operating on the dictionary. + When an item is removed from the dictionary, QDict update all iterators + that are referring the removed item to point to the next item in the + traversing order. + + \sa QDict, \link collection.html Collection Classes\endlink +*/ + +/*! + \fn QDictIterator::QDictIterator( const QDict<type> &dict ) + Constructs an iterator for \e dict. The current iterator item is + set to point on the first item in the \e dict. +*/ + +/*! + \fn QDictIterator::~QDictIterator() + Destroys the iterator. +*/ + +/*! + \fn uint QDictIterator::count() const + Returns the number of items in the dictionary this iterator operates on. + \sa isEmpty() +*/ + +/*! + \fn bool QDictIterator::isEmpty() const + Returns TRUE if the dictionary is empty, i.e. count() == 0, otherwise FALSE. + \sa count() +*/ + +/*! + \fn type *QDictIterator::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 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. +*/ + +/*! + \fn QString QDictIterator::currentKey() const + Returns a pointer to the key for the current iterator item. +*/ + +/*! + \fn type *QDictIterator::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 *QDictIterator::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 *QDictIterator::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. +*/ + + |