Inherits QPtrCollection.
QAsciiDict is implemented as a template class. Define a template instance QAsciiDict<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 char* used for insertion, removal and lookup. The value is a pointer. Dictionaries provide very fast insertion and lookup.
QAsciiDict cannot handle Unicode keys; use the QDict template instead, which uses QString keys. A QDict has the same performace as a QAsciiDict.
Example:
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. See QPtrDict, QIntDict and QDict.
QAsciiDict<QLineEdit> fields; // char* keys, QLineEdit* values
fields.insert( "forename", new QLineEdit( this ) );
fields.insert( "surname", new QLineEdit( this ) );
fields["forename"]->setText( "Homer" );
fields["surname"]->setText( "Simpson" );
QAsciiDictIterator<QLineEdit> it( fields ); // See QAsciiDictIterator
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;
See QDict for full details, including the choice of dictionary size, and how deletions are handled.
See also QAsciiDictIterator, QDict, QIntDict, QPtrDict, Collection Classes, Collection Classes, and Non-GUI Classes.
We recommend setting size to a suitably large prime number (a bit larger than the expected number of entries). This makes the hash distribution better and will improve lookup performance.
When caseSensitive is TRUE (the default) QAsciiDict treats" abc" and "Abc" as different keys; when it is FALSE "abc" and" Abc" are the same. Case-insensitive comparison only considers the 26 letters in US-ASCII.
If copyKeys is TRUE (the default), the dictionary copies keys using strcpy(); if it is FALSE, the dictionary just copies the pointers.
Each item in dict is inserted into this dictionary. Only the pointers are copied (shallow copy).
The items are deleted if auto-delete is enabled.
All iterators that access this dictionary will be reset.
The removed items are deleted if auto-deletion is enabled.
All dictionary iterators that operate on dictionary are reset.
See also remove(), take(), and setAutoDelete().
Reimplemented from QPtrCollection.
See also isEmpty().
Reimplemented from QPtrCollection.
This function uses an internal hashing algorithm to optimize lookup.
If there are two or more items with equal keys, then the item that was most recently inserted will be found.
Equivalent to the [] operator.
Multiple items can have the same key, in which case only the last item will be accessible using operator[]().
item may not be 0.
This dictionary is first cleared and then each item in dict is inserted into this dictionary. Only the pointers are copied (shallow copy) unless newItem() has been reimplemented().
This function uses an internal hashing algorithm to optimize lookup.
If there are two or more items with equal keys, then the item that was most recently inserted will be found.
Equivalent to the find() function.
The default implementation sets item to 0.
If there are two or more items with equal keys, then the most recently inserted item will be removed.
The removed item is deleted if auto-deletion is enabled.
All dictionary iterators that refer to the removed item will be set to point to the next item in the dictionary traversal order.
See also take(), clear(), and setAutoDelete().
If the item does not already exist, it will be inserted.
item may not be 0.
Equivalent to:
QAsciiDict<char> dict;
...
if ( dict.find(key) )
dict.remove( key );
dict.insert( key, item );
If there are two or more items with equal keys, then the most recently inserted item will be replaced.
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.
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.
Note that the auto-delete setting may also affect other functions in subclasses. For example, a subclass that has a remove() function will remove the item from its data structure, and if auto-delete is enabled, will also delete the item.
See also autoDelete().
If there are two or more items with equal keys, then the most recently inserted item 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.
See also remove(), clear(), and setAutoDelete().
See also read().