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Chapter 22
Linked Lists
This chapter describes the NSPR API for managing linked lists. The API
is a set of macros for initializing a circular (doubly linked) list, inserting
and removing elements from the list. The macros are not thread safe and
the caller has to provide to mutually-exclusive access to the list and
the nodes being added/removed from the list.
Types
PRCList
A circular linked list.
Syntax
#include <prclist.h>
typedef struct PRCListStr PRCList;
struct PRCListStr {
PRCList *next;
PRCList *prev;
};
Description
PRClist defines a node in a circular linked list. It can be used as the
anchor of a list and can be embedded in data structures that are maintained
in a linked list.
Macros
PR_INIT_CLIST
Initialize a circular list.
Syntax
#include <prclist.h>
PR_INIT_CLIST(PRCList *listp);
Parameters
The macro has the following parameters:
| listp |
Pointer to the anchor of the linked
list. |
Description
PR_INIT_CLIST initializes the list pointed to by listp to be an
empty list.
PR_INIT_STATIC_CLIST
Statically Initialize a circular list.
Syntax
#include <prclist.h>
PR_INIT_STATIC_CLIST(PRCList *listp);
Parameters
The macro has the following parameters:
| listp |
Pointer to the anchor of the linked
list. |
Description
PR_INIT_STATIC_CLIST statically initializes the list pointed to
by listp to be an empty list. For example,
PRCList free_object_list = PR_INIT_STATIC_CLIST(&free_object_list);
PR_APPEND_LINK
Append an element to the end of the list.
Syntax
#include <prclist.h>
PR_APPEND_LINK(PRCList *elemp, PRCList *listp);
Parameters
The macro has the following parameters:
| elemp |
Pointer to the element to be inserted. |
| listp |
Pointer to the list. |
Description
PR_APPEND_LINK adds the element pointed to by elemp to the end
of the list pointed to by listp.
PR_INSERT_LINK
Insert an element at the head of the list.
Syntax
#include <prclist.h>
PR_INSERT_LINK(PRCList *elemp, PRCList *listp);
Parameters
The macro has the following parameters:
| elemp |
Pointer to the element to be inserted. |
| listp |
Pointer to the list. |
Description
PR_INSERT_LINK inserts the element pointed to by elemp at the
head of the list pointed to by listp.
PR_NEXT_LINK
Return the next element in the list.
Syntax
#include <prclist.h>
PR_NEXT_LINK(PRCList *elemp);
Parameters
The macro has the following parameters:
| elemp |
Pointer to the element. |
Description
PR_NEXT_LINK returns a pointer to the element following the one
pointed to by elemp and can be used to traverse the list. The following
element is not removed from the list.
PR_PREV_LINK
Return the preceding element in the list.
Syntax
#include <prclist.h>
PR_PREV_LINK(PRCList *elemp);
Parameters
The macro has the following parameters:
| elemp |
Pointer to the element. |
Description
PR_NEXT_LINK returns a pointer to the element preceding the one
pointed to by elemp and can be used to traverse the list. The preceding
element is not removed from the list.
PR_REMOVE_LINK
Remove an element from the circular list.
Syntax
#include <prclist.h>
PR_REMOVE_LINK(PRCList *elemp);
Parameters
The macro has the following parameters:
| elemp |
Pointer to the element. |
Description
PR_REMOVE_LINK removes the element pointed to by elemp from it's
circular list.
PR_REMOVE_AND_INIT_LINK
Remove an element from the circular list and initialize the linkage.
Syntax
#include <prclist.h>
PR_REMOVE_AND_INIT_LINK(PRCList *elemp);
Parameters
The macro has the following parameters:
| elemp |
Pointer to the element. |
Description
PR_REMOVE_AND_INIT_LINK removes the element pointed to by elemp
from it's circular list and initializes the links of the element to point
to itself.
PR_INSERT_BEFORE
Insert an element before another element in the circular list.
Syntax
#include <prclist.h>
PR_INSERT_BEFORE(PRCList *elemp1, PRCList *elemp2);
Parameters
The macro has the following parameters:
| elemp1 |
Pointer to the element to be inserted. |
| elemp2 |
Pointer to the element before which elemp2 is to be inserted. |
Description
PR_INSERT_BEFORE inserts elemp1 into the circular list, before
elemp2.
PR_INSERT_AFTER
Insert an element after another element in the circular list.
Syntax
#include <prclist.h>
PR_INSERT_AFTER(PRCList *elemp1, PRCList *elemp2);
Parameters
The macro has the following parameters:
| elemp1 |
Pointer to the element to be inserted. |
| elemp2 |
Pointer to the element after which elemp2 is to be inserted. |
Description
PR_INSERT_AFTER inserts elemp1 into the circular list, after elemp2.
PR_CLIST_IS_EMPTY
Check for an empty circular list.
Syntax
#include <prclist.h>
PR_CLIST_IS_EMPTY(PRCList *listp);
Parameters
The macro has the following parameters:
| listp |
pointer to the linked list. |
Description
PR_CLIST_IS_EMPTY returns a non-zero value if the list pointed
to by listp is an empty list, otherwise returns zero.
PR_LIST_HEAD
Return the head of the circular list.
Syntax
#include <prclist.h>
PR_LIST_HEAD(PRCList *listp);
Parameters
The macro has the following parameters:
| listp |
Pointer to the linked list. |
Description
PR_LIST_HEAD returns the head of the circular list.
PR_LIST_TAIL
Return the tail of the circular list.
Syntax
#include <prclist.h>
PR_LIST_TAIL(PRCList *listp);
Parameters
The macro has the following parameters:
| listp |
Pointer to the linked list. |
Description
PR_LIST_TAIL returns the tail of the circular list.
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Last Updated: Tue Jul 14 17:31:16 PDT 1998
Copyright © 1998 Netscape
Communications Corporation
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