xref: /onnv-gate/usr/src/lib/libc/port/gen/tsearch.c (revision 0:68f95e015346)
1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate  * CDDL HEADER START
3*0Sstevel@tonic-gate  *
4*0Sstevel@tonic-gate  * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate  * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate  * (the "License").  You may not use this file except in compliance
7*0Sstevel@tonic-gate  * with the License.
8*0Sstevel@tonic-gate  *
9*0Sstevel@tonic-gate  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate  * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate  * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate  * and limitations under the License.
13*0Sstevel@tonic-gate  *
14*0Sstevel@tonic-gate  * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate  * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate  * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate  * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate  *
20*0Sstevel@tonic-gate  * CDDL HEADER END
21*0Sstevel@tonic-gate  */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24*0Sstevel@tonic-gate  * Use is subject to license terms.
25*0Sstevel@tonic-gate  */
26*0Sstevel@tonic-gate 
27*0Sstevel@tonic-gate #pragma ident	"%Z%%M%	%I%	%E% SMI"
28*0Sstevel@tonic-gate 
29*0Sstevel@tonic-gate /*	Copyright (c) 1988 AT&T	*/
30*0Sstevel@tonic-gate /*	  All Rights Reserved  	*/
31*0Sstevel@tonic-gate 
32*0Sstevel@tonic-gate 
33*0Sstevel@tonic-gate /*
34*0Sstevel@tonic-gate  * Tree search algorithm, generalized from Knuth (6.2.2) Algorithm T.
35*0Sstevel@tonic-gate  *
36*0Sstevel@tonic-gate  *
37*0Sstevel@tonic-gate  * The NODE * arguments are declared in the lint files as char *,
38*0Sstevel@tonic-gate  * because the definition of NODE isn't available to the user.
39*0Sstevel@tonic-gate  */
40*0Sstevel@tonic-gate 
41*0Sstevel@tonic-gate #pragma weak tdelete = _tdelete
42*0Sstevel@tonic-gate #pragma weak tsearch = _tsearch
43*0Sstevel@tonic-gate #pragma weak twalk = _twalk
44*0Sstevel@tonic-gate 
45*0Sstevel@tonic-gate #include "synonyms.h"
46*0Sstevel@tonic-gate #include "mtlib.h"
47*0Sstevel@tonic-gate #include "libc.h"
48*0Sstevel@tonic-gate #include <sys/types.h>
49*0Sstevel@tonic-gate #include <search.h>
50*0Sstevel@tonic-gate #include <stdlib.h>
51*0Sstevel@tonic-gate #include <thread.h>
52*0Sstevel@tonic-gate #include <synch.h>
53*0Sstevel@tonic-gate 
54*0Sstevel@tonic-gate 
55*0Sstevel@tonic-gate 
56*0Sstevel@tonic-gate typedef struct node { char *key; struct node *llink, *rlink; } NODE;
57*0Sstevel@tonic-gate 
58*0Sstevel@tonic-gate static void __twalk(NODE *, void (*)(const void *, VISIT, int), int);
59*0Sstevel@tonic-gate 
60*0Sstevel@tonic-gate 
61*0Sstevel@tonic-gate /* Find or insert key into search tree */
62*0Sstevel@tonic-gate void *
63*0Sstevel@tonic-gate tsearch(const void *ky, void **rtp, int (*compar)())
64*0Sstevel@tonic-gate {
65*0Sstevel@tonic-gate 	char *key = (char *)ky;
66*0Sstevel@tonic-gate 	NODE **rootp = (NODE **)rtp;
67*0Sstevel@tonic-gate 	NODE *q;	/* New node if key not found */
68*0Sstevel@tonic-gate 
69*0Sstevel@tonic-gate 	if (rootp == NULL)
70*0Sstevel@tonic-gate 		return (NULL);
71*0Sstevel@tonic-gate 	while (*rootp != NULL) {			/* T1: */
72*0Sstevel@tonic-gate 		int r = (*compar)(key, (*rootp)->key);	/* T2: */
73*0Sstevel@tonic-gate 		if (r == 0)
74*0Sstevel@tonic-gate 			return ((void *)*rootp);	/* Key found */
75*0Sstevel@tonic-gate 		rootp = (r < 0) ?
76*0Sstevel@tonic-gate 		    &(*rootp)->llink :		/* T3: Take left branch */
77*0Sstevel@tonic-gate 		    &(*rootp)->rlink;		/* T4: Take right branch */
78*0Sstevel@tonic-gate 	}
79*0Sstevel@tonic-gate 	q = lmalloc(sizeof (NODE));		/* T5: Not found */
80*0Sstevel@tonic-gate 	if (q != NULL) {			/* Allocate new node */
81*0Sstevel@tonic-gate 		*rootp = q;			/* Link new node to old */
82*0Sstevel@tonic-gate 		q->key = key;			/* Initialize new node */
83*0Sstevel@tonic-gate 		q->llink = q->rlink = NULL;
84*0Sstevel@tonic-gate 	}
85*0Sstevel@tonic-gate 	return ((void *)q);
86*0Sstevel@tonic-gate }
87*0Sstevel@tonic-gate 
88*0Sstevel@tonic-gate /* Delete node with key key */
89*0Sstevel@tonic-gate void *
90*0Sstevel@tonic-gate tdelete(const void *ky, void **rtp, int (*compar)())
91*0Sstevel@tonic-gate {
92*0Sstevel@tonic-gate 	char *key = (char *)ky;
93*0Sstevel@tonic-gate 	NODE **rootp = (NODE **)rtp;
94*0Sstevel@tonic-gate 	NODE *p;		/* Parent of node to be deleted */
95*0Sstevel@tonic-gate 	NODE *q;	/* Successor node */
96*0Sstevel@tonic-gate 	NODE *r;	/* Right son node */
97*0Sstevel@tonic-gate 	int ans;		/* Result of comparison */
98*0Sstevel@tonic-gate 
99*0Sstevel@tonic-gate 	if (rootp == NULL || (p = *rootp) == NULL)
100*0Sstevel@tonic-gate 		return (NULL);
101*0Sstevel@tonic-gate 	while ((ans = (*compar)(key, (*rootp)->key)) != 0) {
102*0Sstevel@tonic-gate 		p = *rootp;
103*0Sstevel@tonic-gate 		rootp = (ans < 0) ?
104*0Sstevel@tonic-gate 		    &(*rootp)->llink :		/* Take left branch */
105*0Sstevel@tonic-gate 		    &(*rootp)->rlink;		/* Take right branch */
106*0Sstevel@tonic-gate 		if (*rootp == NULL)
107*0Sstevel@tonic-gate 			return (NULL);		/* Key not found */
108*0Sstevel@tonic-gate 	}
109*0Sstevel@tonic-gate 	r = (*rootp)->rlink;			/* D1: */
110*0Sstevel@tonic-gate 	if ((q = (*rootp)->llink) == NULL)	/* Llink NULL? */
111*0Sstevel@tonic-gate 		q = r;
112*0Sstevel@tonic-gate 	else if (r != NULL) {			/* Rlink NULL? */
113*0Sstevel@tonic-gate 		if (r->llink == NULL) {		/* D2: Find successor */
114*0Sstevel@tonic-gate 			r->llink = q;
115*0Sstevel@tonic-gate 			q = r;
116*0Sstevel@tonic-gate 		} else {			/* D3: Find NULL link */
117*0Sstevel@tonic-gate 			for (q = r->llink; q->llink != NULL; q = r->llink)
118*0Sstevel@tonic-gate 				r = q;
119*0Sstevel@tonic-gate 			r->llink = q->rlink;
120*0Sstevel@tonic-gate 			q->llink = (*rootp)->llink;
121*0Sstevel@tonic-gate 			q->rlink = (*rootp)->rlink;
122*0Sstevel@tonic-gate 		}
123*0Sstevel@tonic-gate 	}
124*0Sstevel@tonic-gate 	lfree(*rootp, sizeof (NODE));		/* D4: Free node */
125*0Sstevel@tonic-gate 	*rootp = q;			/* Link parent to replacement */
126*0Sstevel@tonic-gate 	return ((void *)p);
127*0Sstevel@tonic-gate }
128*0Sstevel@tonic-gate 
129*0Sstevel@tonic-gate 
130*0Sstevel@tonic-gate /* Walk the nodes of a tree */
131*0Sstevel@tonic-gate void
132*0Sstevel@tonic-gate twalk(const void *rt,		/* Root of the tree to be walked */
133*0Sstevel@tonic-gate 	void (*action)(const void *, VISIT, int))
134*0Sstevel@tonic-gate {
135*0Sstevel@tonic-gate 	NODE *root = (NODE *)rt;
136*0Sstevel@tonic-gate 
137*0Sstevel@tonic-gate 	if (root != NULL && action != NULL)
138*0Sstevel@tonic-gate 		__twalk(root, action, 0);
139*0Sstevel@tonic-gate }
140*0Sstevel@tonic-gate 
141*0Sstevel@tonic-gate 
142*0Sstevel@tonic-gate /* Walk the nodes of a tree */
143*0Sstevel@tonic-gate static void
144*0Sstevel@tonic-gate __twalk(NODE *root,		/* Root of the tree to be walked */
145*0Sstevel@tonic-gate 	void (*action)(const void *, VISIT, int),
146*0Sstevel@tonic-gate 	int level)
147*0Sstevel@tonic-gate {
148*0Sstevel@tonic-gate 	if (root->llink == NULL && root->rlink == NULL)
149*0Sstevel@tonic-gate 		(*action)(root, leaf, level);
150*0Sstevel@tonic-gate 	else {
151*0Sstevel@tonic-gate 		(*action)(root, preorder, level);
152*0Sstevel@tonic-gate 		if (root->llink != NULL)
153*0Sstevel@tonic-gate 			__twalk(root->llink, action, level + 1);
154*0Sstevel@tonic-gate 		(*action)(root, postorder, level);
155*0Sstevel@tonic-gate 		if (root->rlink != NULL)
156*0Sstevel@tonic-gate 			__twalk(root->rlink, action, level + 1);
157*0Sstevel@tonic-gate 		(*action)(root, endorder, level);
158*0Sstevel@tonic-gate 	}
159*0Sstevel@tonic-gate }
160