/****************************************************************************
**
** TQMap and TQMapIterator class documentation
**
** Copyright (C) 1992-2008 Trolltech ASA. All rights reserved.
**
** This file is part of the TQt 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 TQt 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.
**
**********************************************************************/
/*****************************************************************************
TQMap documentation
*****************************************************************************/
/*!
\class TQMap tqmap.h
\brief The TQMap class is a value-based template class that
provides a dictionary.
\ingroup tqtl
\ingroup tools
\ingroup shared
\mainclass
TQMap is a TQt implementation of an STL-like map container. It can
be used in your application if the standard \c map is not
available on all your target platforms. TQMap is part of the \link
tqtl.html TQt Template Library\endlink.
TQMap\<Key, Data\> defines a template instance to create a
dictionary with keys of type Key and values of type Data. TQMap
does not store pointers to the members of the map; instead, it
holds a copy of every member. For this reason, TQMap is
value-based, whereas TQPtrList and TQDict are pointer-based.
TQMap contains and manages a collection of objects of type Data
with associated key values of type Key and provides iterators that
allow the contained objects to be addressed. TQMap owns the
contained items.
Some classes cannot be used within a TQMap. For example everything
derived from TQObject and thus all classes that implement widgets.
Only values can be used in a TQMap. To qualify as a value, the
class must provide
\list
\i A copy constructor
\i An assignment operator
\i A default constructor, i.e. a constructor that does not take
any arguments.
\endlist
Note that C++ defaults to field-by-field assignment operators and
copy constructors if no explicit version is supplied. In many
cases, this is sufficient.
The class used for the key requires that the \c operator< is
implemented to define ordering of the keys.
TQMap's function naming is consistent with the other TQt classes
(e.g., count(), isEmpty()). TQMap also provides extra functions for
compatibility with STL algorithms, such as size() and empty().
Programmers already familiar with the STL \c map can use these
the STL-like functions if preferred.
Example:
\target tqmap-eg
\code
#include <tqstring.h>
#include <tqmap.h>
#include <tqstring.h>
class Employee
{
public:
Employee(): sn(0) {}
Employee( const TQString& forename, const TQString& surname, int salary )
: fn(forename), sn(surname), sal(salary)
{ }
TQString forename() const { return fn; }
TQString surname() const { return sn; }
int salary() const { return sal; }
void setSalary( int salary ) { sal = salary; }
private:
TQString fn;
TQString sn;
int sal;
};
int main(int argc, char **argv)
{
TQApplication app( argc, argv );
typedef TQMap<TQString, Employee> EmployeeMap;
EmployeeMap map;
map["JD001"] = Employee("John", "Doe", 50000);
map["JW002"] = Employee("Jane", "Williams", 80000);
map["TJ001"] = Employee("Tom", "Jones", 60000);
Employee sasha( "Sasha", "Hind", 50000 );
map["SH001"] = sasha;
sasha.setSalary( 40000 );
EmployeeMap::Iterator it;
for ( it = map.begin(); it != map.end(); ++it ) {
printf( "%s: %s, %s earns %d\n",
it.key().latin1(),
it.data().surname().latin1(),
it.data().forename().latin1(),
it.data().salary() );
}
return 0;
}
\endcode
Program output:
\code
JD001: Doe, John earns 50000
JW002: Williams, Jane earns 80000
SH001: Hind, Sasha earns 50000
TJ001: Jones, Tom earns 60000
\endcode
The latest changes to Sasha's salary did not affect the value in
the list because the map created a copy of Sasha's entry. In
addition, notice that the items are sorted alphabetically (by key)
when iterating over the map.
There are several ways to find items in a map. The begin() and
end() functions return iterators to the beginning and end of the
map. The advantage of using an iterator is that you can move
forward or backward by incrementing/decrementing the iterator.
The iterator returned by end() points to the element which is one
past the last element in the container. The past-the-end iterator
is still associated with the map it belongs to, however it is \e
not dereferenceable; operator*() will not return a well-defined
value. If the map is empty, the iterator returned by begin() will
equal the iterator returned by end().
Another way to find an element in the map is by using the find()
function. This returns an iterator pointing to the desired item or
to the end() iterator if no such element exists.
Another approach uses the operator[]. But be warned: if the map
does not contain an entry for the element you are looking for,
operator[] inserts a default value. If you do not know that the
element you are searching for is really in the list, you should
not use operator[]. The following example illustrates this:
\code
TQMap<TQString,TQString> map;
map["Clinton"] = "Bill";
str << map["Clinton"] << map["Bush"] << endl;
\endcode
The code fragment will print out "Clinton", "". Since the value
associated with the "Bush" key did not exist, the map inserted a
default value (in this case, an empty string). If you are not
sure whether a certain element is in the map, you should use
find() and iterators instead.
If you just want to know whether a certain key is contained in the
map, use the contains() function. In addition, count() tells you
how many keys are in the map.
It is safe to have multiple iterators at the same time. If some
member of the map is removed, only iterators pointing to the
removed member become invalid; inserting in the map does not
invalidate any iterators.
Since TQMap is value-based, there is no need to be concerned about
deleting items in the map. The map holds its own copies and will
free them if the corresponding member or the map itself is
deleted.
TQMap is implicitly shared. This means you can just make copies of
the map in time O(1). If multiple TQMap instances share the same
data and one is modifying the map's data, this modifying instance
makes a copy and modifies its private copy: so it does not affect
other instances. If a TQMap is being used in a multi-threaded
program, you must protect all access to the map. See \l TQMutex.
There are a couple of ways of inserting new items into the map.
One uses the insert() method; the other uses operator[]:
\code
TQMap<TQString, TQString> map;
map["Clinton"] = "Bill";
map.insert( "Bush", "George" );
\endcode
Items can also be removed from the map in several ways. One way is
to pass an iterator to remove(). Another way is to pass a key
value to remove(), which will delete the entry with the requested
key. In addition you can clear the entire map using the clear()
method.
\sa TQMapIterator
*/
/*! \enum TQMap::key_type
The map's key type. */
/*! \enum TQMap::mapped_type
The map's data type. */
/*! \enum TQMap::value_type
Corresponds to TQPair\<key_type, mapped_type\>. */
/*! \enum TQMap::ValueType
Corresponds to TQPair\<key_type, mapped_type\>, TQt style.*/
/*! \enum TQMap::pointer
Pointer to value_type.*/
/*! \enum TQMap::const_pointer
Const pointer to value_type.*/
/*! \enum TQMap::reference
Reference to value_type.*/
/*! \enum TQMap::const_reference
Const reference to value_type.*/
/*! \enum TQMap::size_type
An unsigned integral type, used to represent various sizes. */
/*! \enum TQMap::iterator
The map's iterator type.*/
/*! \enum TQMap::Iterator
The map's iterator type, TQt style. */
/*! \enum TQMap::const_iterator
The map's const iterator type.*/
/*! \enum TQMap::ConstIterator
The map's const iterator type, TQt style.*/
/*! \enum TQMap::difference_type
\internal */
/*! \enum TQMap::Priv
\internal */
/*!
\fn TQMap::TQMap()
Constructs an empty map.
*/
/*!
\fn TQMap::TQMap( const TQMap<Key,T>& m )
Constructs a copy of \a m.
This operation costs O(1) time because TQMap is implicitly shared.
This makes returning a TQMap from a function very fast. If a shared
instance is modified, it will be copied (copy-on-write), and this
takes O(n) time.
*/
/*!
\fn TQMap::TQMap( const std::map<Key,T>& m )
Constructs a copy of \a m.
*/
/*!
\fn TQMap<Key,T>& TQMap::operator= ( const std::map<Key,T>& m )
\overload
Assigns \a m to this map and returns a reference to this map.
All iterators of the current map become invalidated by this
operation.
*/
/*!
\fn TQMap::~TQMap()
Destroys the map. References to the values in the map and all
iterators of this map become invalidated. Since TQMap is highly
tuned for performance you won't see warnings if you use invalid
iterators, because it is not possible for an iterator to check
whether it is valid or not.
*/
/*!
\fn TQMap<Key, T>& TQMap::operator= (const TQMap<Key, T>& m)
Assigns \a m to this map and returns a reference to this map.
All iterators of the current map become invalidated by this
operation. The cost of such an assignment is O(1), because TQMap is
implicitly shared.
*/
/*!
\fn T& TQMap::operator[] ( const Key& k )
Returns the value associated with the key \a k. If no such key is
present, an empty item is inserted with this key and a reference
to the empty item is returned.
You can use this operator both for reading and writing:
\code
TQMap<TQString, TQString> map;
map["Clinton"] = "Bill";
stream << map["Clinton"];
\endcode
*/
/*!
\fn void TQMap::clear()
Removes all items from the map.
\sa remove()
*/
/*!
\fn Iterator TQMap::find( const Key& k )
Returns an iterator pointing to the element with key \a k in the
map.
Returns end() if no key matched.
\sa TQMapIterator
*/
/*!
\fn ConstIterator TQMap::find( const Key& k ) const
\overload
Returns an iterator pointing to the element with key \a k in the
map.
Returns end() if no key matched.
\sa TQMapConstIterator
*/
/*!
\fn Iterator TQMap::begin()
Returns an iterator pointing to the first element in the map. This
iterator equals end() if the map is empty.
The items in the map are traversed in the order defined by
operator\<(Key, Key).
\sa end() TQMapIterator
*/
/*!
\fn ConstIterator TQMap::begin() const
\overload
\sa end() TQMapConstIterator
*/
/*!
\fn ConstIterator TQMap::constBegin() const
Returns an iterator pointing to the first element in the map. This
iterator equals end() if the map is empty.
The items in the map are traversed in the order defined by
operator\<(Key, Key).
\sa constEnd() TQMapConstIterator
*/
/*!
\fn Iterator TQMap::end()
The iterator returned by end() points to the element which is one
past the last element in the container. The past-the-end iterator
is still associated with the map it belongs to, but it is \e not
dereferenceable; operator*() will not return a well-defined value.
This iterator equals begin() if the map is empty.
\sa begin() TQMapIterator
*/
/*!
\fn ConstIterator TQMap::end() const
\overload
*/
/*!
\fn ConstIterator TQMap::constEnd() const
The iterator returned by end() points to the element which is one
past the last element in the container. The past-the-end iterator
is still associated with the map it belongs to, but it is \e not
dereferenceable; operator*() will not return a well-defined value.
This iterator equals constBegin() if the map is empty.
\sa constBegin() TQMapConstIterator
*/
/*!
\fn void TQMap::detach()
If the map does not share its data with another TQMap instance,
nothing happens; otherwise the function creates a new copy of this
map and detaches from the shared one. This function is called
whenever the map is modified. The implicit sharing mechanism is
implemented this way.
*/
/*!
\fn TQDataStream& operator>>( TQDataStream& s, TQMap<Key,T>& m )
\relates TQMap
Reads the map \a m from the stream \a s. The types \e Key and \e T
must implement the streaming operator as well.
*/
/*!
\fn TQDataStream& operator<<( TQDataStream& s, const TQMap<Key,T>& m )
\relates TQMap
Writes the map \a m to the stream \a s. The types \e Key and \e T
must implement the streaming operator as well.
*/
/*!
\fn size_type TQMap::size() const
Returns the number of items in the map.
This function is provided for STL compatibility. It is equivalent
to count().
\sa empty()
*/
/*!
\fn bool TQMap::empty() const
Returns TRUE if the map contains no items; otherwise returns
FALSE.
This function is provided for STL compatibility. It is equivalent
to isEmpty().
\sa size()
*/
/*!
\fn TQPair<iterator,bool> TQMap::insert( const value_type& x )
\overload
Inserts the (key, value) pair \a x into the map. \a x is a TQPair
whose \c first element is a key to be inserted and whose \c second
element is the associated value to be inserted. Returns a pair
whose \c first element is an iterator pointing to the inserted
item and whose \c second element is a bool indicating TRUE if \a x
was inserted and FALSE if it was not inserted, e.g. because it was
already present.
\sa replace()
*/
/*!
\fn void TQMap::erase( iterator it )
Removes the item associated with the iterator \a it from the map.
This function is provided for STL compatibility. It is equivalent
to remove().
\sa clear()
*/
/*!
\fn void TQMap::erase( const key_type& k )
\overload
Removes the item with the key \a k from the map.
*/
/*!
\fn size_type TQMap::count( const key_type& k ) const
Returns the number of items whose key is \a k. Since TQMap does not
allow duplicate keys, the return value is always 0 or 1.
This function is provided for STL compatibility.
*/
/*!
\fn Iterator TQMap::replace( const Key& k, const T& v )
Replaces the value of the element with key \a k, with the value \a
v.
\sa insert() remove()
*/
/*!
\fn const T& TQMap::operator[] ( const Key& k ) const
\overload
\warning This function differs from the non-const version of the
same function. It will \e not insert an empty value if the key \a
k does not exist. This may lead to logic errors in your program.
You should check if the element exists before calling this
function.
Returns the value associated with the key \a k. If no such key is
present, a reference to an empty item is returned.
*/
/*!
\fn uint TQMap::count() const
\overload
Returns the number of items in the map.
\sa isEmpty()
*/
/*!
\fn bool TQMap::isEmpty() const
Returns TRUE if the map contains no items; otherwise returns
FALSE.
\sa count()
*/
/*!
\fn Iterator TQMap::insert( const Key& key, const T& value, bool overwrite )
Inserts a new item with the key, \a key, and a value of \a value.
If there is already an item whose key is \a key, that item's value
is replaced with \a value, unless \a overwrite is FALSE (it is
TRUE by default). In this case an iterator to this item is
returned, else an iterator to the new item is returned.
*/
/*!
\fn void TQMap::remove( iterator it )
Removes the item associated with the iterator \a it from the map.
\sa clear()
*/
/*!
\fn void TQMap::remove( const Key& k )
\overload
Removes the item with the key \a k from the map.
*/
/*!
\fn bool TQMap::contains( const Key& k ) const
Returns TRUE if the map contains an item with key \a k; otherwise
returns FALSE.
*/
/*****************************************************************************
TQMapIterator documentation
*****************************************************************************/
/*!
\class TQMapIterator tqmap.h
\brief The TQMapIterator class provides an iterator for TQMap.
\ingroup tqtl
\ingroup tools
You cannot create an iterator by yourself. Instead, you must ask a
map to give you one. An iterator is as big as a pointer; on 32-bit
machines that means 4 bytes, on 64-bit machines, 8 bytes. That
makes copying iterators very fast. Iterators behave in a similar
way to pointers, and they are almost as fast as pointers. See the
\link tqmap.html#tqmap-eg TQMap example\endlink.
TQMap is highly optimized for performance and memory usage, but the
trade-off is that you must be more careful. The only way to
traverse a map is to use iterators. TQMap does not know about its
iterators, and the iterators don't even know to which map they
belong. That makes things fast but a bit dangerous because it is
up to you to make sure that the iterators you are using are still
valid. TQDictIterator will be able to give warnings, whereas
TQMapIterator may end up in an undefined state.
For every Iterator there is also a ConstIterator. You must use the
ConstIterator to access a TQMap in a const environment or if the
reference or pointer to the map is itself const. Its semantics are
the same, but it only returns const references to the item it
points to.
\sa TQMap TQMapConstIterator
*/
/*! \enum TQMapIterator::iterator_category
The type of iterator category, \c std::bidirectional_iterator_tag. */
/*! \enum TQMapIterator::value_type
The type of value. */
/*! \enum TQMapIterator::pointer
Pointer to value_type. */
/*! \enum TQMapIterator::reference
Reference to value_type. */
/*! \enum TQMapIterator::difference_type
\internal */
/*! \enum TQMapIterator::NodePtr
\internal */
/*!
\fn TQMapIterator::TQMapIterator()
Creates an uninitialized iterator.
*/
/*!
\fn TQMapIterator::TQMapIterator (TQMapNode<K, T> * p)
Constructs an iterator starting at node \a p.
*/
/*!
\fn TQMapIterator::TQMapIterator( const TQMapIterator<K,T>& it )
Constructs a copy of the iterator, \a it.
*/
/*!
\fn TQMapIterator<K,T>& TQMapIterator::operator++()
Prefix ++ makes the succeeding item current and returns an
iterator pointing to the new current item. The iterator cannot
check whether it reached the end of the map. Incrementing the
iterator returned by end() causes undefined results.
*/
/*!
\fn TQMapIterator<K,T> TQMapIterator::operator++(int)
\overload
Postfix ++ makes the succeeding item current and returns an
iterator pointing to the new current item. The iterator cannot
check whether it reached the end of the map. Incrementing the
iterator returned by end() causes undefined results.
*/
/*!
\fn TQMapIterator<K,T>& TQMapIterator::operator--()
Prefix -- makes the previous item current and returns an iterator
pointing to the new current item. The iterator cannot check
whether it reached the beginning of the map. Decrementing the
iterator returned by begin() causes undefined results.
*/
/*!
\fn TQMapIterator<K,T> TQMapIterator::operator--(int)
\overload
Postfix -- makes the previous item current and returns an iterator
pointing to the new current item. The iterator cannot check
whether it reached the beginning of the map. Decrementing the
iterator returned by begin() causes undefined results.
*/
/*!
\fn T& TQMapIterator::operator*()
Dereference operator. Returns a reference to the current item's
data. The same as data().
*/
/*!
\fn const T& TQMapIterator::operator*() const
\overload
Dereference operator. Returns a const reference to the current
item's data. The same as data().
*/
/*!
\fn bool TQMapIterator::operator==( const TQMapIterator<K,T>& it ) const
Compares the iterator to the \a it iterator and returns TRUE if
they point to the same item; otherwise returns FALSE.
*/
/*!
\fn bool TQMapIterator::operator!=( const TQMapIterator<K,T>& it ) const
Compares the iterator to the \a it iterator and returns FALSE if
they point to the same item; otherwise returns TRUE.
*/
/*!
\fn T& TQMapIterator::data()
Returns a reference to the current item's data.
*/
/*!
\fn const T& TQMapIterator::data() const
\overload
Returns a const reference to the current item's data.
*/
/*!
\fn const K& TQMapIterator::key() const
Returns a const reference to the current item's key.
*/
/*!
\fn TQValueList<Key> TQMap::keys() const
Returns a list of all the keys in the map, in order.
*/
/*!
\fn TQValueList<T> TQMap::values() const
Returns a list of all the values in the map, in key order.
*/
/*****************************************************************************
TQMapConstIterator documentation
*****************************************************************************/
/*!
\class TQMapConstIterator tqmap.h
\brief The TQMapConstIterator class provides an iterator for TQMap.
\ingroup tqtl
\ingroup tools
In contrast to TQMapIterator, this class is used to iterate over a
const map. It does not allow you to modify the values of the map
because this would break the const semantics.
For more information on TQMap iterators, see \l{TQMapIterator} and
the \link tqmap.html#tqmap-eg TQMap example\endlink.
\sa TQMap TQMapIterator
*/
/*! \enum TQMapConstIterator::iterator_category
The type of iterator category, \c std::bidirectional_iterator_tag. */
/*! \enum TQMapConstIterator::value_type
The type of const value. */
/*! \enum TQMapConstIterator::pointer
Const pointer to value_type. */
/*! \enum TQMapConstIterator::reference
Const reference to value_type. */
/*! \enum TQMapConstIterator::difference_type
\internal */
/*! \enum TQMapConstIterator::NodePtr
\internal */
/*!
\fn TQMapConstIterator::TQMapConstIterator()
Constructs an uninitialized iterator.
*/
/*!
\fn TQMapConstIterator::TQMapConstIterator (TQMapNode<K, T> * p)
Constructs an iterator starting at node \a p.
*/
/*!
\fn TQMapConstIterator::TQMapConstIterator( const TQMapConstIterator<K,T>& it )
Constructs a copy of the iterator, \a it.
*/
/*!
\fn TQMapConstIterator::TQMapConstIterator( const TQMapIterator<K,T>& it )
Constructs a copy of the iterator, \a it.
*/
/*!
\fn TQMapConstIterator<K,T>& TQMapConstIterator::operator++()
Prefix ++ makes the succeeding item current and returns an
iterator pointing to the new current item. The iterator cannot
check whether it reached the end of the map. Incrementing the
iterator returned by end() causes undefined results.
*/
/*!
\fn TQMapConstIterator<K,T> TQMapConstIterator::operator++(int)
\overload
Postfix ++ makes the succeeding item current and returns an
iterator pointing to the new current item. The iterator cannot
check whether it reached the end of the map. Incrementing the
iterator returned by end() causes undefined results.
*/
/*!
\fn TQMapConstIterator<K,T>& TQMapConstIterator::operator--()
Prefix -- makes the previous item current and returns an iterator
pointing to the new current item. The iterator cannot check
whether it reached the beginning of the map. Decrementing the
iterator returned by begin() causes undefined results.
*/
/*!
\fn TQMapConstIterator<K,T> TQMapConstIterator::operator--(int)
\overload
Postfix -- makes the previous item current and returns an iterator
pointing to the new current item. The iterator cannot check
whether it reached the beginning of the map. Decrementing the
iterator returned by begin() causes undefined results.
*/
/*!
\fn const T& TQMapConstIterator::operator*() const
Dereference operator. Returns a const reference to the current
item's data. The same as data().
*/
/*!
\fn bool TQMapConstIterator::operator==( const TQMapConstIterator<K,T>& it ) const
Compares the iterator to the \a it iterator and returns TRUE if
they point to the same item; otherwise returns FALSE.
*/
/*!
\fn bool TQMapConstIterator::operator!=( const TQMapConstIterator<K,T>& it ) const
Compares the iterator to the \a it iterator and returns FALSE if
they point to the same item; otherwise returns TRUE.
*/
/*!
\fn const T& TQMapConstIterator::data() const
Returns a const reference to the current item's data.
*/
/*!
\fn const K& TQMapConstIterator::key() const
Returns a const reference to the current item's key.
*/