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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 00:53:35 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 00:53:35 +0000 |
commit | 69c6a41ffb878ef98c9378ed4b1634a404cfaa7f (patch) | |
tree | b2a4f704565d62fbb129ab9dc3b35977c50e6e7f /src/libdnssec/list/ucw_clists.h | |
parent | Initial commit. (diff) | |
download | knot-upstream/2.7.6.tar.xz knot-upstream/2.7.6.zip |
Adding upstream version 2.7.6.upstream/2.7.6upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/libdnssec/list/ucw_clists.h')
-rw-r--r-- | src/libdnssec/list/ucw_clists.h | 260 |
1 files changed, 260 insertions, 0 deletions
diff --git a/src/libdnssec/list/ucw_clists.h b/src/libdnssec/list/ucw_clists.h new file mode 100644 index 0000000..080d01e --- /dev/null +++ b/src/libdnssec/list/ucw_clists.h @@ -0,0 +1,260 @@ +/* + * UCW Library -- Circular Linked Lists + * + * (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 \p l or NULL if \p 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 \p l or NULL if \p 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 \p n or NULL if \p 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 \p n or NULL if \p 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 \p l is empty. + **/ +static inline int clist_empty(clist *l) +{ + return (l->head.next == &l->head); +} + +/** + * Loop over all nodes in the \ref list and perform the next C statement on them. The current node is stored in \p 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 \ref 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 \ref CLIST_WALK(), but it defines the variable for the current node in place. \p 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 \ref CLIST_WALK_DELSAFE(), but it defines the variable for the current node in place. \p 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 \ref 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 \p after. To insert at the head of the list, use \ref clist_add_head() instead. + **/ +static inline void clist_insert_after(cnode *what, cnode *after) +{ + cnode *before = after->next; + what->next = before; + what->prev = after; + before->prev = what; + after->next = what; +} + +/** + * Insert a new node just before the node \p before. To insert at the tail of the list, use \ref clist_add_tail() instead. + **/ +static inline void clist_insert_before(cnode *what, cnode *before) +{ + cnode *after = before->prev; + what->next = before; + what->prev = after; + before->prev = what; + after->next = what; +} + +/** + * Insert a new node in front of all other nodes. + **/ +static inline void clist_add_head(clist *l, cnode *n) +{ + clist_insert_after(n, &l->head); +} + +/** + * Insert a new node after all other nodes. + **/ +static inline void clist_add_tail(clist *l, cnode *n) +{ + clist_insert_before(n, &l->head); +} + +/** + * Remove node \p n. + **/ +static inline void clist_remove(cnode *n) +{ + cnode *before = n->prev; + cnode *after = n->next; + before->next = after; + after->prev = before; +} + +/** + * Remove the first node in \p 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); + if (n) + clist_remove(n); + return n; +} + +/** + * Remove the last node in \p 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); + if (n) + clist_remove(n); + return n; +} + +/** + * Merge two lists by inserting the list \p what just after the node \p 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)) + { + cnode *w = &what->head; + w->prev->next = after->next; + after->next->prev = w->prev; + w->next->prev = after; + after->next = w->next; + clist_init(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 \p l. Beware of linear time complexity. + **/ +static inline unsigned int clist_size(clist *l) +{ + unsigned int i = 0; + CLIST_FOR_EACH(cnode *, n, *l) + i++; + return i; +} + +/** + * Remove a node \p 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 \p 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 \p 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 \ref clist_remove() do not mark nodes + * as unlinked, you need to call \ref clist_unlink() instead. + **/ +static inline int clist_is_linked(cnode *n) +{ + return !!n->next; +} + +#endif |