1 /* 2 * CDDL HEADER START 3 * 4 * The contents of this file are subject to the terms of the 5 * Common Development and Distribution License, Version 1.0 only 6 * (the "License"). You may not use this file except in compliance 7 * with the License. 8 * 9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE 10 * or http://www.opensolaris.org/os/licensing. 11 * See the License for the specific language governing permissions 12 * and limitations under the License. 13 * 14 * When distributing Covered Code, include this CDDL HEADER in each 15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE. 16 * If applicable, add the following below this CDDL HEADER, with the 17 * fields enclosed by brackets "[]" replaced with your own identifying 18 * information: Portions Copyright [yyyy] [name of copyright owner] 19 * 20 * CDDL HEADER END 21 */ 22 /* Copyright (c) 1984 AT&T */ 23 /* All Rights Reserved */ 24 25 #pragma ident "%Z%%M% %I% %E% SMI" /* from S5R2 1.2 */ 26 27 /*LINTLIBRARY*/ 28 /* 29 * Tree search algorithm, generalized from Knuth (6.2.2) Algorithm T. 30 * 31 * The NODE * arguments are declared in the lint files as char *, 32 * because the definition of NODE isn't available to the user. 33 */ 34 35 #include <search.h> 36 typedef char *POINTER; 37 typedef struct node { POINTER key; struct node *llink, *rlink; } NODE; 38 39 #define NULL 0 40 41 42 /* tfind - find a node, or return 0 */ 43 NODE * 44 tfind(key, rootp, compar) 45 POINTER key; /* Key to be located */ 46 register NODE **rootp; /* Address of the root of the tree */ 47 int (*compar)(); /* Comparison function */ 48 { 49 if (rootp == NULL) 50 return (NULL); 51 while (*rootp != NULL) { /* T1: */ 52 int r = (*compar)(key, (*rootp)->key); /* T2: */ 53 if (r == 0) 54 return (*rootp); /* Key found */ 55 rootp = (r < 0) ? 56 &(*rootp)->llink : /* T3: Take left branch */ 57 &(*rootp)->rlink; /* T4: Take right branch */ 58 } 59 return (NODE *)(NULL); 60 } 61