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 * The node_t structure is for internal use only, lint doesn't grok it. 864566a3eSAlfred Perlstein * 964566a3eSAlfred Perlstein * Written by reading the System V Interface Definition, not the code. 1064566a3eSAlfred Perlstein * 1164566a3eSAlfred Perlstein * Totally public domain. 1264566a3eSAlfred Perlstein */ 1364566a3eSAlfred Perlstein 1464566a3eSAlfred Perlstein #include <sys/cdefs.h> 15333fc21eSDavid E. O'Brien #if 0 1664566a3eSAlfred Perlstein #if defined(LIBC_SCCS) && !defined(lint) 1764566a3eSAlfred Perlstein __RCSID("$NetBSD: tfind.c,v 1.2 1999/09/16 11:45:37 lukem Exp $"); 1864566a3eSAlfred Perlstein #endif /* LIBC_SCCS and not lint */ 19333fc21eSDavid E. O'Brien #endif 20333fc21eSDavid E. O'Brien __FBSDID("$FreeBSD$"); 2164566a3eSAlfred Perlstein 2264566a3eSAlfred Perlstein #define _SEARCH_PRIVATE 2364566a3eSAlfred Perlstein #include <stdlib.h> 2464566a3eSAlfred Perlstein #include <search.h> 2564566a3eSAlfred Perlstein 26*f98e0c9dSCraig Rodrigues /* 27*f98e0c9dSCraig Rodrigues * find a node, or return 0 28*f98e0c9dSCraig Rodrigues * 29*f98e0c9dSCraig Rodrigues * vkey - key to be found 30*f98e0c9dSCraig Rodrigues * vrootp - address of the tree root 31*f98e0c9dSCraig Rodrigues */ 3264566a3eSAlfred Perlstein void * 33*f98e0c9dSCraig Rodrigues tfind(const void *vkey, void * const *vrootp, 34*f98e0c9dSCraig Rodrigues int (*compar)(const void *, const void *)) 3564566a3eSAlfred Perlstein { 3664566a3eSAlfred Perlstein node_t **rootp = (node_t **)vrootp; 3764566a3eSAlfred Perlstein 3864566a3eSAlfred Perlstein if (rootp == NULL) 3964566a3eSAlfred Perlstein return NULL; 4064566a3eSAlfred Perlstein 4164566a3eSAlfred Perlstein while (*rootp != NULL) { /* T1: */ 4264566a3eSAlfred Perlstein int r; 4364566a3eSAlfred Perlstein 4464566a3eSAlfred Perlstein if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */ 4564566a3eSAlfred Perlstein return *rootp; /* key found */ 4664566a3eSAlfred Perlstein rootp = (r < 0) ? 4764566a3eSAlfred Perlstein &(*rootp)->llink : /* T3: follow left branch */ 4864566a3eSAlfred Perlstein &(*rootp)->rlink; /* T4: follow right branch */ 4964566a3eSAlfred Perlstein } 5064566a3eSAlfred Perlstein return NULL; 5164566a3eSAlfred Perlstein } 52