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