164566a3eSAlfred Perlstein /* $NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $ */ 264566a3eSAlfred Perlstein 364566a3eSAlfred Perlstein /* 464566a3eSAlfred Perlstein * Tree search generalized from Knuth (6.2.2) Algorithm T just like 564566a3eSAlfred Perlstein * the AT&T man page says. 664566a3eSAlfred Perlstein * 764566a3eSAlfred Perlstein * Written by reading the System V Interface Definition, not the code. 864566a3eSAlfred Perlstein * 964566a3eSAlfred Perlstein * Totally public domain. 1064566a3eSAlfred Perlstein */ 1164566a3eSAlfred Perlstein 1264566a3eSAlfred Perlstein #include <sys/cdefs.h> 13333fc21eSDavid E. O'Brien #if 0 1464566a3eSAlfred Perlstein #if defined(LIBC_SCCS) && !defined(lint) 1564566a3eSAlfred Perlstein __RCSID("$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $"); 1664566a3eSAlfred Perlstein #endif /* LIBC_SCCS and not lint */ 17333fc21eSDavid E. O'Brien #endif 18333fc21eSDavid E. O'Brien __FBSDID("$FreeBSD$"); 1964566a3eSAlfred Perlstein 2064566a3eSAlfred Perlstein #define _SEARCH_PRIVATE 2164566a3eSAlfred Perlstein #include <stdlib.h> 2264566a3eSAlfred Perlstein #include <search.h> 2364566a3eSAlfred Perlstein 24f98e0c9dSCraig Rodrigues /* 25f98e0c9dSCraig Rodrigues * find a node, or return 0 26f98e0c9dSCraig Rodrigues * 27f98e0c9dSCraig Rodrigues * vkey - key to be found 28f98e0c9dSCraig Rodrigues * vrootp - address of the tree root 29f98e0c9dSCraig Rodrigues */ 30*4ef9bd22SEd Schouten posix_tnode * 31*4ef9bd22SEd Schouten tfind(const void *vkey, posix_tnode * const *rootp, 32f98e0c9dSCraig Rodrigues int (*compar)(const void *, const void *)) 3364566a3eSAlfred Perlstein { 3464566a3eSAlfred Perlstein 3564566a3eSAlfred Perlstein if (rootp == NULL) 3664566a3eSAlfred Perlstein return NULL; 3764566a3eSAlfred Perlstein 3864566a3eSAlfred Perlstein while (*rootp != NULL) { /* T1: */ 3964566a3eSAlfred Perlstein int r; 4064566a3eSAlfred Perlstein 4164566a3eSAlfred Perlstein if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */ 4264566a3eSAlfred Perlstein return *rootp; /* key found */ 4364566a3eSAlfred Perlstein rootp = (r < 0) ? 4464566a3eSAlfred Perlstein &(*rootp)->llink : /* T3: follow left branch */ 4564566a3eSAlfred Perlstein &(*rootp)->rlink; /* T4: follow right branch */ 4664566a3eSAlfred Perlstein } 4764566a3eSAlfred Perlstein return NULL; 4864566a3eSAlfred Perlstein } 49