1 /* $NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $ */ 2 3 /* 4 * Tree search generalized from Knuth (6.2.2) Algorithm T just like 5 * the AT&T man page says. 6 * 7 * The node_t structure is for internal use only, lint doesn't grok it. 8 * 9 * Written by reading the System V Interface Definition, not the code. 10 * 11 * Totally public domain. 12 */ 13 14 #include <sys/cdefs.h> 15 #if 0 16 #if defined(LIBC_SCCS) && !defined(lint) 17 __RCSID("$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $"); 18 #endif /* LIBC_SCCS and not lint */ 19 #endif 20 __FBSDID("$FreeBSD$"); 21 22 #define _SEARCH_PRIVATE 23 #include <stdlib.h> 24 #include <search.h> 25 26 /* 27 * find a node, or return 0 28 * 29 * vkey - key to be found 30 * vrootp - address of the tree root 31 */ 32 void * 33 tfind(const void *vkey, void * const *vrootp, 34 int (*compar)(const void *, const void *)) 35 { 36 node_t **rootp = (node_t **)vrootp; 37 38 if (rootp == NULL) 39 return NULL; 40 41 while (*rootp != NULL) { /* T1: */ 42 int r; 43 44 if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */ 45 return *rootp; /* key found */ 46 rootp = (r < 0) ? 47 &(*rootp)->llink : /* T3: follow left branch */ 48 &(*rootp)->rlink; /* T4: follow right branch */ 49 } 50 return NULL; 51 } 52