| /* $OpenBSD: tfind.c,v 1.6 2014/03/16 18:38:30 guenther Exp $ */ |
| |
| /* |
| * Tree search generalized from Knuth (6.2.2) Algorithm T just like |
| * the AT&T man page says. |
| * |
| * The node_t structure is for internal use only |
| * |
| * Written by reading the System V Interface Definition, not the code. |
| * |
| * Totally public domain. |
| */ |
| /*LINTLIBRARY*/ |
| #include <search.h> |
| |
| typedef struct node_t |
| { |
| char *key; |
| struct node_t *llink, *rlink; |
| } node; |
| |
| /* find a node, or return 0 */ |
| void * |
| tfind(const void *vkey, void * const *vrootp, |
| int (*compar)(const void *, const void *)) |
| { |
| char *key = (char *)vkey; |
| node **rootp = (node **)vrootp; |
| |
| if (rootp == (struct node_t **)0) |
| return ((struct node_t *)0); |
| while (*rootp != (struct node_t *)0) { /* T1: */ |
| int r; |
| if ((r = (*compar)(key, (*rootp)->key)) == 0) /* T2: */ |
| return (*rootp); /* key found */ |
| rootp = (r < 0) ? |
| &(*rootp)->llink : /* T3: follow left branch */ |
| &(*rootp)->rlink; /* T4: follow right branch */ |
| } |
| return (node *)0; |
| } |
