1*8a29851fSPedro F. Giffuni /* $NetBSD: tsearch.c,v 1.7 2012/06/25 22:32:45 abs 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) 17*8a29851fSPedro F. Giffuni __RCSID("$NetBSD: tsearch.c,v 1.7 2012/06/25 22:32:45 abs 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 <search.h> 2464566a3eSAlfred Perlstein #include <stdlib.h> 2564566a3eSAlfred Perlstein 2664566a3eSAlfred Perlstein /* find or insert datum into search tree */ 2764566a3eSAlfred Perlstein void * 28*8a29851fSPedro F. Giffuni tsearch(const void *vkey, void **vrootp, 29*8a29851fSPedro F. Giffuni int (*compar)(const void *, const void *)) 3064566a3eSAlfred Perlstein { 3164566a3eSAlfred Perlstein node_t *q; 3264566a3eSAlfred Perlstein node_t **rootp = (node_t **)vrootp; 3364566a3eSAlfred Perlstein 3464566a3eSAlfred Perlstein if (rootp == NULL) 3564566a3eSAlfred Perlstein return NULL; 3664566a3eSAlfred Perlstein 3764566a3eSAlfred Perlstein while (*rootp != NULL) { /* Knuth's T1: */ 3864566a3eSAlfred Perlstein int r; 3964566a3eSAlfred Perlstein 4064566a3eSAlfred Perlstein if ((r = (*compar)(vkey, (*rootp)->key)) == 0) /* T2: */ 4164566a3eSAlfred Perlstein return *rootp; /* we found it! */ 4264566a3eSAlfred Perlstein 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 4864566a3eSAlfred Perlstein q = malloc(sizeof(node_t)); /* T5: key not found */ 4964566a3eSAlfred Perlstein if (q != 0) { /* make new node */ 5064566a3eSAlfred Perlstein *rootp = q; /* link new node to old */ 51*8a29851fSPedro F. Giffuni q->key = __DECONST(void *, vkey);/* initialize new node */ 5264566a3eSAlfred Perlstein q->llink = q->rlink = NULL; 5364566a3eSAlfred Perlstein } 5464566a3eSAlfred Perlstein return q; 5564566a3eSAlfred Perlstein } 56