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QGList Class Reference

The QGList class is an internal class for implementing Qt collection classes. More...

#include <qglist.h>

Inherits QCollection.

List of all member functions.

Protected Members

• bool operator== ( const QGList & list ) const
• void sort ()
• virtual int compareItems ( QCollection::Item item1, QCollection::Item item2 )
• virtual QDataStream & read ( QDataStream & s, QCollection::Item & item )
• virtual QDataStream & write ( QDataStream & s, QCollection::Item ) const

Detailed Description

QGList is a strictly internal class that acts as a base class for several collection classes; QList, QQueue and QStack.

QGList has some virtual functions that can be reimplemented to customize the subclasses.

• compareItems() compares two collection/list items.
• read() reads a collection/list item from a QDataStream.
• write() writes a collection/list item to a QDataStream.

Member Function Documentation

int QGList::compareItems ( QCollection::Item item1, QCollection::Item item2 ) [virtual protected]

Returns:

• 0 if item1 == item2
• non-zero if item1 != item2

This function returns int rather than bool so that reimplementations can return three values and use it to sort by:

• 0 if item1 == item2
• > 0 (positive integer) if item1 > item2
• < 0 (negative integer) if item1 < item2

The QList::inSort() function requires that compareItems() is implemented as described here.

This function should not modify the list because some const functions call compareItems().

The default implementation compares the pointers:

bool QGList::operator== ( const QGList & list ) const [protected]

QDataStream & QGList::read ( QDataStream & s, QCollection::Item & item ) [virtual protected]

The default implementation sets item to 0.

See also write().

void QGList::sort () [protected]

The Heap-Sort algorithm is used for sorting. It sorts n items with O(n*log n) compares. This is the asymptotic optimal solution of the sorting problem.

QDataStream & QGList::write ( QDataStream & s, QCollection::Item ) const [virtual protected]

The default implementation does nothing.

See also read().

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