xref: /illumos-gate/usr/src/cmd/logadm/lut.c (revision e911f249)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 /*
22  * Copyright 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  *
25  * logadm/lut.c -- simple lookup table module
26  *
27  * this file contains a very simple lookup table (lut) implementation.
28  * the tables only support insert & lookup, no delete, and can
29  * only be walked in lexical order.  if the key already exists
30  * for something being inserted, the previous entry is simply
31  * replaced.  the left-hand-side (lhs), which is the key, is
32  * copied into malloc'd memory.  the right-hand-side (rhs), which
33  * is the datum, is not copied (in fact, the lut routines don't
34  * know the size or type of the datum, just the void * pointer to it).
35  *
36  * yea, this module could be much fancier and do much more, but
37  * the idea was to keep it really simple and just provide what
38  * was needed by logadm for options processing.
39  */
40 
41 #include <stdio.h>
42 #include <strings.h>
43 #include "err.h"
44 #include "lut.h"
45 
46 /* forward declarations of functions private to this module */
47 static void dooper(const char *lhs, void *rhs, void *arg);
48 
49 /* info created by lut_add() and lut_dup(), private to this module */
50 struct lut {
51 	struct lut *lut_left;
52 	struct lut *lut_right;
53 	char *lut_lhs;		/* search key */
54 	void *lut_rhs;		/* the datum */
55 };
56 
57 /*
58  * lut_add -- add an entry to the table
59  *
60  * use it like this:
61  *	struct lut *root = NULL;
62  *	root = lut_add(root, "key", value);
63  *
64  * the key string gets strdup'd by lut_add(), but the memory holding
65  * the *value should not be freed until the lut is freed by lut_free().
66  */
67 struct lut *
lut_add(struct lut * root,const char * lhs,void * rhs)68 lut_add(struct lut *root, const char *lhs, void *rhs)
69 {
70 	int diff = 0;
71 
72 	if (root == NULL) {
73 		/* not in tree, create new node */
74 		root = MALLOC(sizeof (*root));
75 		root->lut_lhs = STRDUP(lhs);
76 		root->lut_rhs = rhs;
77 		root->lut_left = root->lut_right = NULL;
78 	} else if (lhs != NULL && (diff = strcmp(root->lut_lhs, lhs)) == 0) {
79 		/* already in tree, replace node */
80 		root->lut_rhs = rhs;
81 	} else if (diff > 0)
82 		root->lut_left = lut_add(root->lut_left, lhs, rhs);
83 	else
84 		root->lut_right = lut_add(root->lut_right, lhs, rhs);
85 	return (root);
86 }
87 
88 /* helper function for lut_dup() */
89 static void
dooper(const char * lhs,void * rhs,void * arg)90 dooper(const char *lhs, void *rhs, void *arg)
91 {
92 	struct lut **rootp = (struct lut **)arg;
93 
94 	*rootp = lut_add(*rootp, lhs, rhs);
95 }
96 
97 /*
98  * lut_dup -- duplicate a lookup table
99  *
100  * caller is responsible for keeping track of how many tables are keeping
101  * pointers to the void * datum values.
102  */
103 struct lut *
lut_dup(struct lut * root)104 lut_dup(struct lut *root)
105 {
106 	struct lut *ret = NULL;
107 
108 	lut_walk(root, dooper, &ret);
109 
110 	return (ret);
111 }
112 
113 /*
114  * lut_lookup -- find an entry
115  */
116 void *
lut_lookup(struct lut * root,const char * lhs)117 lut_lookup(struct lut *root, const char *lhs)
118 {
119 	int diff;
120 
121 	if (root == NULL || lhs == NULL)
122 		return (NULL);
123 	else if ((diff = strcmp(root->lut_lhs, lhs)) == 0)
124 		return (root->lut_rhs);
125 	else if (diff > 0)
126 		return (lut_lookup(root->lut_left, lhs));
127 	else
128 		return (lut_lookup(root->lut_right, lhs));
129 }
130 
131 /*
132  * lut_walk -- walk the table in lexical order
133  */
134 void
lut_walk(struct lut * root,void (* callback)(const char * lhs,void * rhs,void * arg),void * arg)135 lut_walk(struct lut *root,
136     void (*callback)(const char *lhs, void *rhs, void *arg), void *arg)
137 {
138 	if (root) {
139 		lut_walk(root->lut_left, callback, arg);
140 		(*callback)(root->lut_lhs, root->lut_rhs, arg);
141 		lut_walk(root->lut_right, callback, arg);
142 	}
143 }
144 
145 /*
146  * lut_free -- free a lut
147  *
148  * if callback is provided, it is called for each value in the table.
149  * it the values are things that the caller malloc'd, then you can do:
150  *	lut_free(root, free);
151  */
152 void
lut_free(struct lut * root,void (* callback)(void * rhs))153 lut_free(struct lut *root, void (*callback)(void *rhs))
154 {
155 	if (root != NULL) {
156 		lut_free(root->lut_left, callback);
157 		lut_free(root->lut_right, callback);
158 		FREE(root->lut_lhs);
159 		if (callback)
160 			(*callback)(root->lut_rhs);
161 		FREE(root);
162 	}
163 }
164 
165 
166 #ifdef	TESTMODULE
167 
168 void
printer(const char * lhs,void * rhs,void * arg)169 printer(const char *lhs, void *rhs, void *arg)
170 {
171 	printf("<%s> <%s> (<%s>)\n", lhs, (char *)rhs,
172 	    (char *)lut_lookup(arg, lhs));
173 }
174 
175 /*
176  * test main for lut module, usage: a.out [lhs[=rhs]...]
177  */
178 int
main(int argc,char * argv[])179 main(int argc, char *argv[])
180 {
181 	struct lut *r = NULL;
182 	struct lut *dupr = NULL;
183 	char *equals;
184 
185 	err_init(argv[0]);
186 	setbuf(stdout, NULL);
187 
188 	for (argv++; *argv; argv++)
189 		if ((equals = strchr(*argv, '=')) != NULL) {
190 			*equals++ = '\0';
191 			r = lut_add(r, *argv, equals);
192 		} else
193 			r = lut_add(r, *argv, "NULL");
194 
195 	printf("lut contains:\n");
196 	lut_walk(r, printer, r);
197 
198 	dupr = lut_dup(r);
199 
200 	lut_free(r, NULL);
201 
202 	printf("dup lut contains:\n");
203 	lut_walk(dupr, printer, dupr);
204 
205 	lut_free(dupr, NULL);
206 
207 	err_done(0);
208 	/* NOTREACHED */
209 	return (0);
210 }
211 
212 #endif	/* TESTMODULE */
213