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