/*
* UCW Library -- Circular Linked Lists
*
- * (c) 2003--2007 Martin Mares <mj@ucw.cz>
+ * (c) 2003--2010 Martin Mares <mj@ucw.cz>
*
* This software may be freely distributed and used according to the terms
* of the GNU Lesser General Public License.
#ifndef _UCW_CLISTS_H
#define _UCW_CLISTS_H
+/**
+ * Common header for list nodes.
+ **/
typedef struct cnode {
struct cnode *next, *prev;
} cnode;
+/**
+ * Circular doubly linked list.
+ **/
typedef struct clist {
struct cnode head;
} clist;
+/**
+ * Initialize a new circular linked list. Must be called before any other function.
+ **/
+static inline void clist_init(clist *l)
+{
+ cnode *head = &l->head;
+ head->next = head->prev = head;
+}
+
+/**
+ * Return the first node on @l or NULL if @l is empty.
+ **/
static inline void *clist_head(clist *l)
{
return (l->head.next != &l->head) ? l->head.next : NULL;
}
+/**
+ * Return the last node on @l or NULL if @l is empty.
+ **/
static inline void *clist_tail(clist *l)
{
return (l->head.prev != &l->head) ? l->head.prev : NULL;
}
+/**
+ * Find the next node to @n or NULL if @n is the last one.
+ **/
static inline void *clist_next(clist *l, cnode *n)
{
return (n->next != &l->head) ? (void *) n->next : NULL;
}
+/**
+ * Find the previous node to @n or NULL if @n is the first one.
+ **/
static inline void *clist_prev(clist *l, cnode *n)
{
return (n->prev != &l->head) ? (void *) n->prev : NULL;
}
+/**
+ * Return a non-zero value iff @l is empty.
+ **/
static inline int clist_empty(clist *l)
{
return (l->head.next == &l->head);
}
+/**
+ * Loop over all nodes in the @list and perform the next C statement on them. The current node is stored in @n which must be defined before as pointer to any type.
+ * The list should not be changed during this loop command.
+ **/
#define CLIST_WALK(n,list) for(n=(void*)(list).head.next; (cnode*)(n) != &(list).head; n=(void*)((cnode*)(n))->next)
+
+/**
+ * Same as @CLIST_WALK(), but allows removal of the current node. This macro requires one more variable to store some temporary pointers.
+ **/
#define CLIST_WALK_DELSAFE(n,list,tmp) for(n=(void*)(list).head.next; tmp=(void*)((cnode*)(n))->next, (cnode*)(n) != &(list).head; n=(void*)tmp)
+
+/**
+ * Same as @CLIST_WALK(), but it defines the variable for the current node in place. @type should be a pointer type.
+ **/
#define CLIST_FOR_EACH(type,n,list) for(type n=(void*)(list).head.next; (cnode*)(n) != &(list).head; n=(void*)((cnode*)(n))->next)
+
+/**
+ * Same as @CLIST_WALK_DELSAFE(), but it defines the variable for the current node in place. @type should be a pointer type. The temporary variable must be still known before.
+ **/
#define CLIST_FOR_EACH_DELSAFE(type,n,list,tmp) for(type n=(void*)(list).head.next; tmp=(void*)((cnode*)(n))->next, (cnode*)(n) != &(list).head; n=(void*)tmp)
+/**
+ * Reversed version of @CLIST_FOR_EACH().
+ **/
#define CLIST_FOR_EACH_BACKWARDS(type,n,list) for(type n=(void*)(list).head.prev; (cnode*)(n) != &(list).head; n=(void*)((cnode*)(n))->prev)
+/**
+ * Insert a new node just after the node @after. To insert at the head of the list, use @clist_add_head() instead.
+ **/
static inline void clist_insert_after(cnode *what, cnode *after)
{
cnode *before = after->next;
after->next = what;
}
+/**
+ * Insert a new node just before the node @before. To insert at the tail of the list, use @clist_add_tail() instead.
+ **/
static inline void clist_insert_before(cnode *what, cnode *before)
{
cnode *after = before->prev;
after->next = what;
}
-static inline void clist_add_tail(clist *l, cnode *n)
+/**
+ * Insert a new node in front of all other nodes.
+ **/
+static inline void clist_add_head(clist *l, cnode *n)
{
- clist_insert_before(n, &l->head);
+ clist_insert_after(n, &l->head);
}
-static inline void clist_add_head(clist *l, cnode *n)
+/**
+ * Insert a new node after all other nodes.
+ **/
+static inline void clist_add_tail(clist *l, cnode *n)
{
- clist_insert_after(n, &l->head);
+ clist_insert_before(n, &l->head);
}
+/**
+ * Remove node @n.
+ **/
static inline void clist_remove(cnode *n)
{
cnode *before = n->prev;
after->prev = before;
}
+/**
+ * Remove the first node in @l, if it exists. Return the pointer to that node or NULL.
+ **/
static inline void *clist_remove_head(clist *l)
{
cnode *n = clist_head(l);
return n;
}
+/**
+ * Remove the last node in @l, if it exists. Return the pointer to that node or NULL.
+ **/
static inline void *clist_remove_tail(clist *l)
{
cnode *n = clist_tail(l);
return n;
}
-static inline void clist_init(clist *l)
-{
- cnode *head = &l->head;
- head->next = head->prev = head;
-}
-
+/**
+ * Merge two lists by inserting the list @what just after the node @after in a different list.
+ * The first list is then cleared.
+ **/
static inline void clist_insert_list_after(clist *what, cnode *after)
{
if (!clist_empty(what))
}
}
+/**
+ * Move all items from a source list to a destination list. The source list
+ * becomes empty, the original contents of the destination list are destroyed.
+ **/
+static inline void clist_move(clist *to, clist *from)
+{
+ clist_init(to);
+ clist_insert_list_after(from, &to->head);
+ clist_init(from);
+}
+
+/**
+ * Compute the number of nodes in @l. Beware of linear time complexity.
+ **/
static inline uns clist_size(clist *l)
{
uns i = 0;
return i;
}
+/**
+ * Remove a node @n and mark it as unlinked by setting the previous and next pointers to NULL.
+ **/
+static inline void clist_unlink(cnode *n)
+{
+ clist_remove(n);
+ n->prev = n->next = NULL;
+}
+
+/**
+ * Remove the first node on @l and mark it as unlinked.
+ * Return the pointer to that node or NULL.
+ **/
+static inline void *clist_unlink_head(clist *l)
+{
+ cnode *n = clist_head(l);
+ if (n)
+ clist_unlink(n);
+ return n;
+}
+
+/**
+ * Remove the last node on @l and mark it as unlinked.
+ * Return the pointer to that node or NULL.
+ **/
+static inline void *clist_unlink_tail(clist *l)
+{
+ cnode *n = clist_tail(l);
+ if (n)
+ clist_unlink(n);
+ return n;
+}
+
+/**
+ * Check if a node is linked a list. Unlinked nodes are recognized by having their
+ * previous and next pointers equal to NULL. Returns 0 or 1.
+ *
+ * Nodes initialized to all zeroes are unlinked, inserting a node anywhere in a list
+ * makes it linked. Normal removal functions like clist_remove() do not mark nodes
+ * as unlinked, you need to call clist_unlink() instead.
+ **/
+static inline int clist_is_linked(cnode *n)
+{
+ return !!n->next;
+}
+
#endif
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