The Q3PtrList class is a template class that provides a list. 更多...
| 头： | #include <Q3PtrList> |
| 继承： | Q3PtrCollection |
| 继承者： | Q3StrList |
| Q3PtrList () | |
| Q3PtrList (const Q3PtrList<type> & list ) | |
| ~Q3PtrList () | |
| void | append (const type * item ) |
| type * | at (uint index ) |
| int | at () const |
| uint | contains (const type * item ) const |
| uint | containsRef (const type * item ) const |
| type * | current () const |
| Q3LNode * | currentNode () const |
| int | find (const type * item ) |
| int | findNext (const type * item ) |
| int | findNextRef (const type * item ) |
| int | findRef (const type * item ) |
| type * | first () |
| type * | getFirst () const |
| type * | getLast () const |
| void | inSort (const type * item ) |
| bool | insert (uint index , const type * item ) |
| bool | isEmpty () const |
| type * | last () |
| type * | next () |
| void | prepend (const type * item ) |
| type * | prev () |
| bool | remove (uint index ) |
| bool | remove () |
| bool | remove (const type * item ) |
| bool | removeFirst () |
| bool | removeLast () |
| void | removeNode (Q3LNode * node ) |
| bool | removeRef (const type * item ) |
| bool | replace (uint index , const type * item ) |
| void | sort () |
| type * | take (uint index ) |
| type * | take () |
| type * | takeNode (Q3LNode * node ) |
| void | toVector (Q3GVector * vec ) const |
| bool | operator!= (const Q3PtrList<type> & list ) const |
| Q3PtrList<type> & | operator= (const Q3PtrList<type> & list ) |
| bool | operator== (const Q3PtrList<type> & list ) const |
| virtual void | clear () |
| virtual uint | count () const |
| virtual int | compareItems (Q3PtrCollection::Item item1 , Q3PtrCollection::Item item2 ) |
| virtual QDataStream & | read (QDataStream & s , Q3PtrCollection::Item & item ) |
| virtual QDataStream & | write (QDataStream & s , Q3PtrCollection::Item item ) const |
The Q3PtrList class is a template class that provides a list.
Q3ValueList is an STL-compatible alternative to this class.
Define a template instance Q3PtrList <X> to create a list that operates on pointers to X (X*).
The list class is indexable and has a current index 和 current item . The first item corresponds to index position 0. The current index is -1 if the current item is 0.
Items are inserted with prepend (), insert () 或 append (). Items are removed with remove (), removeRef (), removeFirst () 和 removeLast (). You can search for an item using find (), findNext (), findRef () 或 findNextRef (). The list can be sorted with sort (). You can count the number of occurrences of an item with contains () 或 containsRef (). You can get a pointer to the current item with current (), to an item at a particular index position in the list with at () or to the first or last item with getFirst () 和 getLast (). You can also iterate over the list with first (), last (), next () 和 prev () (which all update current ()). The list's deletion property is set with setAutoDelete ().
范例：
class Employee { public: Employee() : sn( 0 ) { } Employee( const QString& forename, const QString& surname, int salary ) : fn( forename ), sn( surname ), sal( salary ) { } void setSalary( int salary ) { sal = salary; } QString forename() const { return fn; } QString surname() const { return sn; } int salary() const { return sal; } private: QString fn; QString sn; int sal; }; Q3PtrList<Employee> list; list.setAutoDelete( TRUE ); // the list owns the objects list.append( new Employee("John", "Doe", 50000) ); list.append( new Employee("Jane", "Williams", 80000) ); list.append( new Employee("Tom", "Jones", 60000) ); Employee *employee; for ( employee = list.first(); employee; employee = list.next() ) cout << employee->surname().latin1() << ", " << employee->forename().latin1() << " earns " << employee->salary() << endl; cout << endl; // very inefficient for big lists for ( uint i = 0; i < list.count(); ++i ) if ( list.at(i) ) cout << list.at( i )->surname().latin1() << endl;
The output is
Doe, John earns 50000 Williams, Jane earns 80000 Jones, Tom earns 60000 Doe Williams Jones
Q3PtrList has several member functions for traversing the list, but using a Q3PtrListIterator can be more practical. Multiple list iterators may traverse the same list, independently of each other and of the current list item.
In the example above we make the call setAutoDelete (true). Enabling auto-deletion tells the list to delete items that are removed. The default is to not delete items when they are removed but this would cause a memory leak in the example because there are no other references to the list items.
When inserting an item into a list only the pointer is copied, not the item itself, i.e. a shallow copy. It is possible to make the list copy all of the item's data (deep copy) when an item is inserted. insert (), inSort () 和 append () call the virtual function Q3PtrCollection::newItem () for the item to be inserted. Inherit a list and reimplement newItem () to have deep copies.
When removing an item from a list, the virtual function Q3PtrCollection::deleteItem () 被调用。 Q3PtrList 's default implementation is to delete the item if auto-deletion is enabled.
The virtual function compareItems () can be reimplemented to compare two list items. This function is called from all list functions that need to compare list items, for instance remove(const type*). If you only want to deal with pointers, there are functions that compare pointers instead, for instance removeRef (const type*). These functions are somewhat faster than those that call compareItems ().
List items are stored as
void*
in an internal Q3LNode, which also holds pointers to the next and previous list items. The functions
currentNode
(),
removeNode
()，和
takeNode
() operate directly on the Q3LNode, but they should be used with care. The data component of the node is available through Q3LNode's getData() function.
The
Q3StrList
类是列表化的
char*
. It reimplements
newItem
(),
deleteItem
() 和
compareItems
(). (But see
QStringList
for a list of Unicode QStrings.)
另请参阅 Q3PtrListIterator .
构造空列表。
构造副本为 list .
Each item in list is appended to this list. Only the pointers are copied (shallow copy).
Removes all items from the list and destroys the list.
All list iterators that access this list will be reset.
另请参阅 setAutoDelete ().
插入 item 在列表末尾。
The inserted item becomes the current list item. This is equivalent to
insert( count(), item )
.
item must not be 0.
另请参阅 insert (), current ()，和 prepend ().
Returns a pointer to the item at position index in the list, or 0 if the index is out of range.
Sets the current list item to this item if
index
is valid. The valid range is
0..(count() - 1)
包括在内。
This function is very efficient. It starts scanning from the first item, last item, or current item, whichever is closest to index .
另请参阅 current ().
这是重载函数。
Returns the index of the current list item. The returned value is -1 if the current item is 0.
另请参阅 current ().
[虚拟]
void
Q3PtrList::
clear
()
重实现自 Q3PtrCollection::clear ().
Removes all items from the list.
The removed items are deleted if auto-deletion is enabled.
All list iterators that access this list will be reset.
另请参阅 remove (), take ()，和 setAutoDelete ().
[virtual protected]
int
Q3PtrList::
compareItems
(
Q3PtrCollection::Item
item1
,
Q3PtrCollection::Item
item2
)
This virtual function compares two list items.
返回：
此函数返回 int 而不是 bool so that reimplementations can return three values and use it to sort by:
inSort () 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.
Returns the number of occurrences of item 在列表中。
The compareItems () function is called when looking for the item in the list. If compareItems () is not reimplemented, it is more efficient to call containsRef ().
This function does not affect the current list item.
另请参阅 containsRef () 和 compareItems ().
Returns the number of occurrences of item 在列表中。
Calling this function is much faster than contains () because contains () compares item with each list item using compareItems (), whereas his function only compares the pointers.
This function does not affect the current list item.
另请参阅 contains ().
[虚拟]
uint
Q3PtrList::
count
() const
重实现自 Q3PtrCollection::count ().
Returns the number of items in the list.
另请参阅 isEmpty ().
Returns a pointer to the current list item. The current item may be 0 (implies that the current index is -1).
另请参阅 at ().
Returns a pointer to the current list node.
The node can be kept and removed later using removeNode (). The advantage is that the item can be removed directly without searching the list.
警告： Do not call this function unless you are an expert.
另请参阅 removeNode (), takeNode ()，和 current ().
Finds the first occurrence of item 在列表中。
If the item is found, the list sets the current item to point to the found item and returns the index of this item. If the item is not found, the list sets the current item to 0, the current index to -1, and returns -1.
The compareItems () function is called when searching for the item in the list. If compareItems () is not reimplemented, it is more efficient to call findRef ().
另请参阅 findNext (), findRef (), compareItems ()，和 current ().
Finds the next occurrence of item in the list, starting from the current list item.
If the item is found, the list sets the current item to point to the found item and returns the index of this item. If the item is not found, the list sets the current item to 0, the current index to -1, and returns -1.
The compareItems () function is called when searching for the item in the list. If compareItems () is not reimplemented, it is more efficient to call findNextRef ().
另请参阅 find (), findNextRef (), compareItems ()，和 current ().
Finds the next occurrence of item in the list, starting from the current list item.
If the item is found, the list sets the current item to point to the found item and returns the index of this item. If the item is not found, the list sets the current item to 0, the current index to -1, and returns -1.
Calling this function is much faster than findNext () because findNext () compares item with each list item using compareItems (), whereas this function only compares the pointers.
另请参阅 findRef (), findNext ()，和 current ().
Finds the first occurrence of item 在列表中。
If the item is found, the list sets the current item to point to the found item and returns the index of this item. If the item is not found, the list sets the current item to 0, the current index to -1, and returns -1.
Calling this function is much faster than find () because find () compares item with each list item using compareItems (), whereas this function only compares the pointers.
另请参阅 findNextRef (), find ()，和 current ().
Returns a pointer to the first item in the list and makes this the current list item; returns 0 if the list is empty.
另请参阅 getFirst (), last (), next (), prev ()，和 current ().
Returns a pointer to the first item in the list, or 0 if the list is empty.
This function does not affect the current list item.
Returns a pointer to the last item in the list, or 0 if the list is empty.
This function does not affect the current list item.
插入 item at its sorted position in the list.
The sort order depends on the virtual compareItems () function. All items must be inserted with inSort() to maintain the sorting order.
The inserted item becomes the current list item.
item must not be 0.
警告： Using inSort() is slow. An alternative, especially if you have lots of items, is to simply append () 或 insert () them and then use sort (). inSort() takes up to O(n) compares. That means inserting n items in your list will need O(n^2) compares whereas sort () only needs O(n*log n) for the same task. So use inSort() only if you already have a presorted list and want to insert just a few additional items.
另请参阅 insert (), compareItems (), current ()，和 sort ().
插入 item 在位置 index 在列表中。
Returns TRUE if successful, i.e. if index is in range; otherwise returns FALSE. The valid range is 0 to count () (inclusively). The item is appended if index == count ().
The inserted item becomes the current list item.
item must not be 0.
另请参阅 append (), current ()，和 replace ().
Returns TRUE if the list is empty; otherwise returns FALSE.
另请参阅 count ().
Returns a pointer to the last item in the list and makes this the current list item; returns 0 if the list is empty.
另请参阅 getLast (), first (), next (), prev ()，和 current ().
Returns a pointer to the item succeeding the current item. Returns 0 if the current item is 0 or equal to the last item.
Makes the succeeding item current. If the current item before this function call was the last item, the current item will be set to 0. If the current item was 0, this function does nothing.
另请参阅 first (), last (), prev ()，和 current ().
插入 item at the start of the list.
The inserted item becomes the current list item. This is equivalent to
insert( 0, item )
.
item must not be 0.
另请参阅 append (), insert ()，和 current ().
Returns a pointer to the item preceding the current item. Returns 0 if the current item is 0 or equal to the first item.
Makes the preceding item current. If the current item before this function call was the first item, the current item will be set to 0. If the current item was 0, this function does nothing.
另请参阅 first (), last (), next ()，和 current ().
[virtual protected]
QDataStream
& Q3PtrList::
read
(
QDataStream
&
s
,
Q3PtrCollection::Item
&
item
)
Reads a list item from the stream s 并返回流引用。
The default implementation sets item 为 0。
另请参阅 write ().
Removes the item at position index 在列表中。
Returns TRUE if successful, i.e. if
index
is in range; otherwise returns FALSE. The valid range is
0..(count() - 1)
包括在内。
The removed item is deleted if auto-deletion is enabled.
The item after the removed item becomes the new current list item if the removed item is not the last item in the list. If the last item is removed, the new last item becomes the current item.
All list iterators that refer to the removed item will be set to point to the new current item.
另请参阅 take (), clear (), setAutoDelete (), current ()，和 removeRef ().
这是重载函数。
Removes the current list item.
Returns TRUE if successful, i.e. if the current item isn't 0; otherwise returns FALSE.
The removed item is deleted if auto-deletion is enabled.
The item after the removed item becomes the new current list item if the removed item is not the last item in the list. If the last item is removed, the new last item becomes the current item. The current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to point to the new current item.
另请参阅 take (), clear (), setAutoDelete (), current ()，和 removeRef ().
这是重载函数。
Removes the first occurrence of item from the list.
Returns TRUE if successful, i.e. if item is in the list; otherwise returns FALSE.
The removed item is deleted if auto-deletion is enabled.
The compareItems () function is called when searching for the item in the list. If compareItems () is not reimplemented, it is more efficient to call removeRef ().
若 item is NULL then the current item is removed from the list.
The item after the removed item becomes the new current list item if the removed item is not the last item in the list. If the last item is removed, the new last item becomes the current item. The current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to point to the new current item.
另请参阅 removeRef (), take (), clear (), setAutoDelete (), compareItems ()，和 current ().
Removes the first item from the list. Returns TRUE if successful, i.e. if the list isn't empty; otherwise returns FALSE.
The removed item is deleted if auto-deletion is enabled.
The first item in the list becomes the new current list item. The current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to point to the new current item.
另请参阅 removeLast (), setAutoDelete (), current ()，和 remove ().
Removes the last item from the list. Returns TRUE if successful, i.e. if the list isn't empty; otherwise returns FALSE.
The removed item is deleted if auto-deletion is enabled.
The last item in the list becomes the new current list item. The current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to point to the new current item.
另请参阅 removeFirst (), setAutoDelete ()，和 current ().
移除 node from the list.
This node must exist in the list, otherwise the program may crash.
The removed item is deleted if auto-deletion is enabled.
The first item in the list will become the new current list item. The current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to point to the item succeeding this item or to the preceding item if the removed item was the last item.
警告： Do not call this function unless you are an expert.
另请参阅 takeNode (), currentNode (), remove ()，和 removeRef ().
Removes the first occurrence of item from the list.
Returns TRUE if successful, i.e. if item is in the list; otherwise returns FALSE.
The removed item is deleted if auto-deletion is enabled.
Equivalent to:
if ( list.findRef( item ) != -1 ) list.remove();
The item after the removed item becomes the new current list item if the removed item is not the last item in the list. If the last item is removed, the new last item becomes the current item. The current item is set to 0 if the list becomes empty.
All list iterators that refer to the removed item will be set to point to the new current item.
另请参阅 remove (), clear (), setAutoDelete ()，和 current ().
Replaces the item at position index with the new item .
Returns TRUE if successful, i.e. index is in the range 0 to count ()-1.
另请参阅 append (), current ()，和 insert ().
Sorts the list by the result of the virtual compareItems () 函数。
The heap sort algorithm is used for sorting. It sorts n items with O(n*log n) comparisons. This is the asymptotic optimal solution of the sorting problem.
If the items in your list support operator<() and operator==(), you might be better off with Q3SortedList because it implements the compareItems () function for you using these two operators.
另请参阅 inSort ().
Takes the item at position index out of the list without deleting it (even if auto-deletion is enabled).
Returns a pointer to the item taken out of the list, or 0 if the index is out of range. The valid range is
0..(count() - 1)
包括在内。
The item after the removed item becomes the new current list item if the removed item is not the last item in the list. If the last item is removed, the new last item becomes the current item. The current item is set to 0 if the list becomes empty.
All list iterators that refer to the taken item will be set to point to the new current item.
另请参阅 remove (), clear ()，和 current ().
这是重载函数。
Takes the current item out of the list without deleting it (even if auto-deletion is enabled).
Returns a pointer to the item taken out of the list, or 0 if the current item is 0.
The item after the removed item becomes the new current list item if the removed item is not the last item in the list. If the last item is removed, the new last item becomes the current item. The current item is set to 0 if the list becomes empty.
All list iterators that refer to the taken item will be set to point to the new current item.
另请参阅 remove (), clear ()，和 current ().
Takes the node out of the list without deleting its item (even if auto-deletion is enabled). Returns a pointer to the item taken out of the list.
This node must exist in the list, otherwise the program may crash.
The first item in the list becomes the new current list item.
All list iterators that refer to the taken item will be set to point to the item succeeding this item or to the preceding item if the taken item was the last item.
警告： Do not call this function unless you are an expert.
另请参阅 removeNode () 和 currentNode ().
Stores all list items in the vector vec .
The vector must be of the same item type, otherwise the result will be undefined.
[virtual protected]
QDataStream
& Q3PtrList::
write
(
QDataStream
&
s
,
Q3PtrCollection::Item
item
) const
Writes a list item, item 到流 s 并返回流引用。
默认实现什么都不做。
另请参阅 read ().
Compares this list with list . Returns TRUE if the lists contain different data; otherwise returns FALSE.
赋值 list to this list and returns a reference to this list.
This list is first cleared and then each item in list is appended to this list. Only the pointers are copied (shallow copy) unless newItem () has been reimplemented.
Compares this list with list . Returns TRUE if the lists contain the same data; otherwise returns FALSE.