1QAsciiDict(3qt) QAsciiDict(3qt)
2
6 QAsciiDict - Template class that provides a dictionary based on char*
7 keys
8
10 #include <qasciidict.h>
11 Inherits QPtrCollection.
13 Public Members
15 QAsciiDict ( int size = 17, bool caseSensitive = TRUE, bool copyKeys =
16 TRUE )
17 QAsciiDict ( const QAsciiDict<type> & dict )
18 ~QAsciiDict ()
19 QAsciiDict<type> & operator= ( const QAsciiDict<type> & dict )
20 virtual uint count () const
21 uint size () const
22 bool isEmpty () const
23 void insert ( const char * key, const type * item )
24 void replace ( const char * key, const type * item )
25 bool remove ( const char * key )
26 type * take ( const char * key )
27 type * find ( const char * key ) const
28 type * operator[] ( const char * key ) const
29 virtual void clear ()
30 void resize ( uint newsize )
31 void statistics () const
32 Important Inherited Members
34 bool autoDelete () const
35 void setAutoDelete ( bool enable )
36 Protected Members
38 virtual QDataStream & read ( QDataStream & s, QPtrCollection::Item &
39 item )
40 virtual QDataStream & write ( QDataStream & s, QPtrCollection::Item )
41 const
42
44 The QAsciiDict class is a template class that provides a dictionary
45 based on char* keys.
46 QAsciiDict is implemented as a template class. Define a template
48 instance QAsciiDict<X> to create a dictionary that operates on pointers
49 to X (X*).
50 A dictionary is a collection of key-value pairs. The key is a char*
52 used for insertion, removal and lookup. The value is a pointer.
53 Dictionaries provide very fast insertion and lookup.
54 QAsciiDict cannot handle Unicode keys; use the QDict template instead,
56 which uses QString keys. A QDict has the same performace as a
57 QAsciiDict.
58 Example:
60 QAsciiDict<QLineEdit> fields; // char* keys, QLineEdit* values
62 fields.insert( "forename", new QLineEdit( this ) );
63 fields.insert( "surname", new QLineEdit( this ) );
64 fields["forename"]->setText( "Homer" );
65 fields["surname"]->setText( "Simpson" );
66 QAsciiDictIterator<QLineEdit> it( fields ); // See QAsciiDictIterator
67 for( ; it.current(); ++it )
68 cout << it.currentKey() << ": " << it.current()->text() << endl;
69 cout << endl;
70 if ( fields["forename"] && fields["surname"] )
71 cout << fields["forename"]->text() << " "
72 << fields["surname"]->text() << endl; // Prints "Homer Simpson"
73 fields.remove( "forename" ); // Does not delete the line edit
74 if ( ! fields["forename"] )
75 cout << "forename is not in the dictionary" << endl;
76 In this example we use a dictionary to keep track of the line edits
77 we're using. We insert each line edit into the dictionary with a unique
78 name and then access the line edits via the dictionary. See QPtrDict,
79 QIntDict and QDict.
80 See QDict for full details, including the choice of dictionary size,
82 and how deletions are handled.
83 See also QAsciiDictIterator, QDict, QIntDict, QPtrDict, Collection
85 Classes, Collection Classes, and Non-GUI Classes.
86
89 copyKeys = TRUE )
90 Constructs a dictionary optimized for less than size entries.
91 We recommend setting size to a suitably large prime number (a bit
93 larger than the expected number of entries). This makes the hash
94 distribution better and will improve lookup performance.
95 When caseSensitive is TRUE (the default) QAsciiDict treats" abc" and
97 "Abc" as different keys; when it is FALSE "abc" and" Abc" are the same.
98 Case-insensitive comparison only considers the 26 letters in US-ASCII.
99 If copyKeys is TRUE (the default), the dictionary copies keys using
101 strcpy(); if it is FALSE, the dictionary just copies the pointers.
102
104 Constructs a copy of dict.
105 Each item in dict is inserted into this dictionary. Only the pointers
107 are copied (shallow copy).
108
110 Removes all items from the dictionary and destroys it.
111 The items are deleted if auto-delete is enabled.
113 All iterators that access this dictionary will be reset.
115 See also setAutoDelete().
117
119 Returns the setting of the auto-delete option. The default is FALSE.
120 See also setAutoDelete().
122
124 Removes all items from the dictionary.
125 The removed items are deleted if auto-deletion is enabled.
127 All dictionary iterators that operate on dictionary are reset.
129 See also remove(), take(), and setAutoDelete().
131 Reimplemented from QPtrCollection.
133
135 Returns the number of items in the dictionary.
136 See also isEmpty().
138 Reimplemented from QPtrCollection.
140
142 Returns the item associated with key, or 0 if the key does not exist in
143 the dictionary.
144 This function uses an internal hashing algorithm to optimize lookup.
146 If there are two or more items with equal keys, then the item that was
148 most recently inserted will be found.
149 Equivalent to the [] operator.
151 See also operator[]().
153
155 Inserts the key with the item into the dictionary.
156 Multiple items can have the same key, in which case only the last item
158 will be accessible using operator[]().
159 item may not be 0.
161 See also replace().
163
165 Returns TRUE if the dictionary is empty, i.e. count() == 0; otherwise
166 it returns FALSE.
167 See also count().
169
171 Assigns dict to this dictionary and returns a reference to this
172 dictionary.
173 This dictionary is first cleared and then each item in dict is inserted
175 into this dictionary. Only the pointers are copied (shallow copy)
176 unless newItem() has been reimplemented().
177
179 Returns the item associated with key, or 0 if the key does not exist in
180 the dictionary.
181 This function uses an internal hashing algorithm to optimize lookup.
183 If there are two or more items with equal keys, then the item that was
185 most recently inserted will be found.
186 Equivalent to the find() function.
188 See also find().
190
192 ) [virtual protected]
193 Reads a dictionary item from the stream s and returns a reference to
194 the stream.
195 The default implementation sets item to 0.
197 See also write().
199
201 Removes the item associated with key from the dictionary. Returns TRUE
202 if successful, i.e. if the key existed in the dictionary; otherwise
203 returns FALSE.
204 If there are two or more items with equal keys, then the most recently
206 inserted item will be removed.
207 The removed item is deleted if auto-deletion is enabled.
209 All dictionary iterators that refer to the removed item will be set to
211 point to the next item in the dictionary traversal order.
212 See also take(), clear(), and setAutoDelete().
214
216 Replaces an item that has a key equal to key with item.
217 If the item does not already exist, it will be inserted.
219 item may not be 0.
221 Equivalent to:
223 QAsciiDict<char> dict;
225 ...
226 if ( dict.find(key) )
227 dict.remove( key );
228 dict.insert( key, item );
229 If there are two or more items with equal keys, then the most recently
231 inserted item will be replaced.
232 See also insert().
234
236 Changes the size of the hashtable to newsize. The contents of the
237 dictionary are preserved but all iterators on the dictionary become
238 invalid.
239
241 Sets the collection to auto-delete its contents if enable is TRUE and
242 to never delete them if enable is FALSE.
243 If auto-deleting is turned on, all the items in a collection are
245 deleted when the collection itself is deleted. This is convenient if
246 the collection has the only pointer to the items.
247 The default setting is FALSE, for safety. If you turn it on, be careful
249 about copying the collection - you might find yourself with two
250 collections deleting the same items.
251 Note that the auto-delete setting may also affect other functions in
253 subclasses. For example, a subclass that has a remove() function will
254 remove the item from its data structure, and if auto-delete is enabled,
255 will also delete the item.
256 See also autoDelete().
258 Examples:
260
262 Returns the size of the internal hash array (as specified in the
263 constructor).
264 See also count().
266
268 Debugging-only function that prints out the dictionary distribution
269 using qDebug().
270
272 Takes the item associated with key out of the dictionary without
273 deleting it (even if auto-deletion is enabled).
274 If there are two or more items with equal keys, then the most recently
276 inserted item will be taken.
277 Returns a pointer to the item taken out, or 0 if the key does not exist
279 in the dictionary.
280 All dictionary iterators that refer to the taken item will be set to
282 point to the next item in the dictionary traversal order.
283 See also remove(), clear(), and setAutoDelete().
285
287 const [virtual protected]
288 Writes a dictionary item to the stream s and returns a reference to the
289 stream.
290 See also read().
292
295 http://doc.trolltech.com/qasciidict.html
296 http://www.trolltech.com/faq/tech.html
297
299 Copyright 1992-2007 Trolltech ASA, http://www.trolltech.com. See the
300 license file included in the distribution for a complete license
301 statement.
302
304 Generated automatically from the source code.
305
307 If you find a bug in Qt, please report it as described in
308 http://doc.trolltech.com/bughowto.html. Good bug reports help us to
309 help you. Thank you.
310 The definitive Qt documentation is provided in HTML format; it is
312 located at $QTDIR/doc/html and can be read using Qt Assistant or with a
313 web browser. This man page is provided as a convenience for those users
314 who prefer man pages, although this format is not officially supported
315 by Trolltech.
316 If you find errors in this manual page, please report them to qt-
318 bugs@trolltech.com. Please include the name of the manual page
319 (qasciidict.3qt) and the Qt version (3.3.8).
320Trolltech AS 2 February 2007 QAsciiDict(3qt)