diff options
Diffstat (limited to 'src/include/lib/dllist.h')
| -rw-r--r-- | src/include/lib/dllist.h | 42 |
1 files changed, 27 insertions, 15 deletions
diff --git a/src/include/lib/dllist.h b/src/include/lib/dllist.h index 9e357a7fd76..9306d4e6b67 100644 --- a/src/include/lib/dllist.h +++ b/src/include/lib/dllist.h @@ -2,12 +2,11 @@ * * dllist.h * simple doubly linked list primitives - * the elements of the list are void* so the lists can contain - * anything + * the elements of the list are void* so the lists can contain anything * Dlelem can only be in one list at a time * * - * Here's a small example of how to use Dllist's : + * Here's a small example of how to use Dllists: * * Dllist *lst; * Dlelem *elt; @@ -24,10 +23,18 @@ * DLFreeElem(elt); -- free the element since we don't * use it anymore * + * + * It is also possible to use Dllist objects that are embedded in larger + * structures instead of being separately malloc'd. To do this, use + * DLInitElem() to initialize a Dllist field within a larger object. + * Don't forget to DLRemove() each field from its list (if any) before + * freeing the larger object! + * + * * Portions Copyright (c) 1996-2000, PostgreSQL, Inc * Portions Copyright (c) 1994, Regents of the University of California * - * $Id: dllist.h,v 1.13 2000/06/08 22:37:46 momjian Exp $ + * $Id: dllist.h,v 1.14 2000/11/16 22:30:43 tgl Exp $ * *------------------------------------------------------------------------- */ @@ -35,7 +42,6 @@ #ifndef DLLIST_H #define DLLIST_H - struct Dllist; struct Dlelem; @@ -53,21 +59,27 @@ typedef struct Dllist Dlelem *dll_tail; } Dllist; -extern Dllist *DLNewList(void); /* initialize a new list */ -extern void DLFreeList(Dllist *); /* free up a list and all the +extern Dllist *DLNewList(void); /* allocate and initialize a list header */ +extern void DLInitList(Dllist *list); /* init a header alloced by caller */ +extern void DLFreeList(Dllist *list); /* free up a list and all the * nodes in it */ extern Dlelem *DLNewElem(void *val); -extern void DLFreeElem(Dlelem *); -extern Dlelem *DLGetHead(Dllist *); -extern Dlelem *DLGetTail(Dllist *); -extern Dlelem *DLRemTail(Dllist *l); -extern Dlelem *DLGetSucc(Dlelem *); /* get successor */ -extern void DLRemove(Dlelem *); /* removes node from list */ +extern void DLInitElem(Dlelem *e, void *val); +extern void DLFreeElem(Dlelem *e); +extern void DLRemove(Dlelem *e); /* removes node from list */ extern void DLAddHead(Dllist *list, Dlelem *node); extern void DLAddTail(Dllist *list, Dlelem *node); extern Dlelem *DLRemHead(Dllist *list); /* remove and return the head */ -extern void DLMoveToFront(Dlelem *); /* move node to front of its list */ +extern Dlelem *DLRemTail(Dllist *list); +extern void DLMoveToFront(Dlelem *e); /* move node to front of its list */ + +/* These are macros for speed */ +#define DLGetHead(list) ((list)->dll_head) +#define DLGetTail(list) ((list)->dll_tail) +#define DLGetSucc(elem) ((elem)->dle_next) +#define DLGetPred(elem) ((elem)->dle_prev) +#define DLGetListHdr(elem) ((elem)->dle_list) -#define DLE_VAL(x) (x->dle_val) +#define DLE_VAL(elem) ((elem)->dle_val) #endif /* DLLIST_H */ |