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 * Written by reading the System V Interface Definition, not the code. 8 * 9 * Totally public domain. 10 */ 11 12 #include <sys/cdefs.h> 13 #if 0 14 #if defined(LIBC_SCCS) && !defined(lint) 15 __RCSID("$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $"); 16 #endif /* LIBC_SCCS and not lint */ 17 #endif 18 __FBSDID("$FreeBSD$"); 19 20 #define _SEARCH_PRIVATE 21 #include <stdlib.h> 22 #include <search.h> 23 24 /* 25 * find a node, or return 0 26 * 27 * vkey - key to be found 28 * vrootp - address of the tree root 29 */ 30 posix_tnode * 31 tfind(const void *vkey, posix_tnode * const *rootp, 32 int (*compar)(const void *, const void *)) 33 { 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