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 /* find a node, or return 0 */ 27 void * 28 tfind(vkey, vrootp, compar) 29 const void *vkey; /* key to be found */ 30 void * const *vrootp; /* address of the tree root */ 31 int (*compar)(const void *, const void *); 32 { 33 node_t **rootp = (node_t **)vrootp; 34 35 if (rootp == NULL) 36 return NULL; 37 38 while (*rootp != NULL) { /* T1: */ 39 int r; 40 41 if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */ 42 return *rootp; /* key found */ 43 rootp = (r < 0) ? 44 &(*rootp)->llink : /* T3: follow left branch */ 45 &(*rootp)->rlink; /* T4: follow right branch */ 46 } 47 return NULL; 48 } 49