ListIterator Class Reference

For use on the stack only: iterates through a the elements of a QoreListNode. More...

#include <QoreListNode.h>

List of all members.

Public Member Functions

DLLEXPORT ListIterator (QoreListNode *lst, qore_size_t n_pos=-1)
 initializes the iterator to the position given or, if omitted, just before the first element
DLLEXPORT bool next ()
 moves the iterator to the next element, returns true if the iterator is pointing to an element of the list
DLLEXPORT bool prev ()
 moves the iterator to the previous element, returns true if the iterator is pointing to an element of the list
DLLEXPORT int set (qore_size_t n_pos)
 sets the iterator to a specific position in the list
DLLEXPORT AbstractQoreNodegetValue () const
 returns a pointer to the value of the list element
DLLEXPORT AbstractQoreNode ** getValuePtr () const
 returns a pointer to a pointer of the value of the list element, so it can be changed externally
DLLEXPORT AbstractQoreNodegetReferencedValue () const
 returns the current value with an incremented reference count
DLLEXPORT bool first () const
 returns true when the iterator is pointing to the first element in the list
DLLEXPORT bool last () const
 returns true when the iterator is pointing to the last element in the list
DLLLOCAL qore_size_t index () const
 returns the current iterator position in the list


Detailed Description

For use on the stack only: iterates through a the elements of a QoreListNode.

   // iterate forward through the list
   ListIterator li(l);
   while (li.next()) {
      QoreStringValueHelper str(li.getValue());
      printf("%d: '%s'\n", li.index(), str->getBuffer());
   }
   // iterate backwards through the list
   ListIterator li(l);
   while (li.prev()) {
      QoreStringValueHelper str(li.getValue());
      printf("%d: '%s'\n", li.index(), str->getBuffer());
   }
See also:
ConstListIterator

Constructor & Destructor Documentation

DLLEXPORT ListIterator::ListIterator ( QoreListNode lst,
qore_size_t  n_pos = -1 
)

initializes the iterator to the position given or, if omitted, just before the first element

Parameters:
lst the list to iterate
n_pos the starting position (-1 means just before the first element so that the initial call to next() or prev() will )


Member Function Documentation

DLLEXPORT bool ListIterator::next (  ) 

moves the iterator to the next element, returns true if the iterator is pointing to an element of the list

if the iterator is on the last element, it moves to an invalid position before the first element and returns false note that a subsequent call to next() after it returns false will move the iterator to the first element again (assuming there is at least one element in the list)

Returns:
returns true if the iterator has been moved to point to a valid element of the list, false if there are no more elements to iterate

DLLEXPORT bool ListIterator::prev (  ) 

moves the iterator to the previous element, returns true if the iterator is pointing to an element of the list

if the iterator is on the first element, it moves to an invalid position before the first element and returns false note that a subsequent call to prev() after it returns false will move the iterator to the last element again (assuming there is at least one element in the list)

Returns:
returns true if the iterator has been moved to point to a valid element of the list, false if there are no more elements to iterate
Note:
after this function returns false, do not use the iterator until it points to a valid element, otherwise a crash will result

DLLEXPORT int ListIterator::set ( qore_size_t  n_pos  ) 

sets the iterator to a specific position in the list

In the case an invalid position is given (element not present in the list), the iterator will not be pointing to a valid element in the list

Parameters:
n_pos the position in the list to set (first element is position 0)
Returns:
0 for OK, -1 for invalid position
Note:
if this function returns -1, do not use the iterator until it points to a valid element, otherwise a crash will result


The documentation for this class was generated from the following file:

Generated on Mon Oct 26 09:09:50 2009 for Qore Programming Language by  doxygen 1.5.6