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 https://opensource.org/licenses/CDDL-1.0.
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 2008 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * Generic doubly-linked list implementation
28 */
29
30 #include <sys/list.h>
31 #include <sys/list_impl.h>
32 #include <sys/types.h>
33 #include <sys/sysmacros.h>
34 #include <sys/debug.h>
35
36 #define list_d2l(a, obj) ((list_node_t *)(((char *)obj) + (a)->list_offset))
37 #define list_object(a, node) ((void *)(((char *)node) - (a)->list_offset))
38 #define list_empty(a) ((a)->list_head.next == &(a)->list_head)
39
40 #define list_insert_after_node(list, node, object) { \
41 list_node_t *lnew = list_d2l(list, object); \
42 lnew->prev = (node); \
43 lnew->next = (node)->next; \
44 (node)->next->prev = lnew; \
45 (node)->next = lnew; \
46 }
47
48 #define list_insert_before_node(list, node, object) { \
49 list_node_t *lnew = list_d2l(list, object); \
50 lnew->next = (node); \
51 lnew->prev = (node)->prev; \
52 (node)->prev->next = lnew; \
53 (node)->prev = lnew; \
54 }
55
56 #define list_remove_node(node) \
57 (node)->prev->next = (node)->next; \
58 (node)->next->prev = (node)->prev; \
59 (node)->next = (node)->prev = NULL
60
61 void
62 list_create(list_t *list, size_t size, size_t offset)
63 {
64 ASSERT(list);
65 ASSERT(size > 0);
66 ASSERT(size >= offset + sizeof (list_node_t));
67
68 list->list_size = size;
69 list->list_offset = offset;
70 list->list_head.next = list->list_head.prev = &list->list_head;
71 }
72
73 void
74 list_destroy(list_t *list)
75 {
76 list_node_t *node = &list->list_head;
77
78 ASSERT(list);
79 ASSERT(list->list_head.next == node);
80 ASSERT(list->list_head.prev == node);
81
82 node->next = node->prev = NULL;
83 }
84
85 void
86 list_insert_after(list_t *list, void *object, void *nobject)
87 {
88 if (object == NULL) {
89 list_insert_head(list, nobject);
90 } else {
91 list_node_t *lold = list_d2l(list, object);
92 list_insert_after_node(list, lold, nobject);
93 }
94 }
95
96 void
97 list_insert_before(list_t *list, void *object, void *nobject)
98 {
99 if (object == NULL) {
100 list_insert_tail(list, nobject);
101 } else {
102 list_node_t *lold = list_d2l(list, object);
103 list_insert_before_node(list, lold, nobject);
104 }
105 }
106
107 void
108 list_insert_head(list_t *list, void *object)
109 {
110 list_node_t *lold = &list->list_head;
111 list_insert_after_node(list, lold, object);
112 }
113
114 void
115 list_insert_tail(list_t *list, void *object)
116 {
117 list_node_t *lold = &list->list_head;
118 list_insert_before_node(list, lold, object);
119 }
120
121 void
122 list_remove(list_t *list, void *object)
123 {
124 list_node_t *lold = list_d2l(list, object);
125 ASSERT(!list_empty(list));
126 ASSERT(lold->next != NULL);
127 list_remove_node(lold);
128 }
129
130 void *
131 list_remove_head(list_t *list)
132 {
133 list_node_t *head = list->list_head.next;
134 if (head == &list->list_head)
135 return (NULL);
136 list_remove_node(head);
137 return (list_object(list, head));
138 }
139
140 void *
141 list_remove_tail(list_t *list)
142 {
143 list_node_t *tail = list->list_head.prev;
144 if (tail == &list->list_head)
145 return (NULL);
146 list_remove_node(tail);
147 return (list_object(list, tail));
148 }
149
150 void *
151 list_head(list_t *list)
152 {
153 if (list_empty(list))
154 return (NULL);
155 return (list_object(list, list->list_head.next));
156 }
157
158 void *
159 list_tail(list_t *list)
160 {
161 if (list_empty(list))
162 return (NULL);
163 return (list_object(list, list->list_head.prev));
164 }
165
166 void *
167 list_next(list_t *list, void *object)
168 {
169 list_node_t *node = list_d2l(list, object);
170
171 if (node->next != &list->list_head)
172 return (list_object(list, node->next));
173
174 return (NULL);
175 }
176
177 void *
178 list_prev(list_t *list, void *object)
179 {
180 list_node_t *node = list_d2l(list, object);
181
182 if (node->prev != &list->list_head)
183 return (list_object(list, node->prev));
184
185 return (NULL);
186 }
187
188 /*
189 * Insert src list after dst list. Empty src list thereafter.
190 */
191 void
192 list_move_tail(list_t *dst, list_t *src)
193 {
194 list_node_t *dstnode = &dst->list_head;
195 list_node_t *srcnode = &src->list_head;
196
197 ASSERT(dst->list_size == src->list_size);
198 ASSERT(dst->list_offset == src->list_offset);
199
200 if (list_empty(src))
201 return;
202
203 dstnode->prev->next = srcnode->next;
204 srcnode->next->prev = dstnode->prev;
205 dstnode->prev = srcnode->prev;
206 srcnode->prev->next = dstnode;
207
208 /* empty src list */
209 srcnode->next = srcnode->prev = srcnode;
210 }
211
212 void
213 list_link_replace(list_node_t *lold, list_node_t *lnew)
214 {
215 ASSERT(list_link_active(lold));
216 ASSERT(!list_link_active(lnew));
217
218 lnew->next = lold->next;
219 lnew->prev = lold->prev;
220 lold->prev->next = lnew;
221 lold->next->prev = lnew;
222 lold->next = lold->prev = NULL;
223 }
224
225 void
226 list_link_init(list_node_t *ln)
227 {
228 ln->next = NULL;
229 ln->prev = NULL;
230 }
231
232 int
233 list_link_active(list_node_t *ln)
234 {
235 EQUIV(ln->next == NULL, ln->prev == NULL);
236 return (ln->next != NULL);
237 }
238
239 int
240 list_is_empty(list_t *list)
241 {
242 return (list_empty(list));
243 }
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