1 /*
2 * Copyright 2008-2013 Various Authors
3 * Copyright 2005 Timo Hirvonen
4 *
5 * This program is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU General Public License as
7 * published by the Free Software Foundation; either version 2 of the
8 * License, or (at your option) any later version.
9 *
10 * This program is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #ifndef CMUS_ITER_H
20 #define CMUS_ITER_H
21
22 #include <stddef.h> /* NULL */
23
24 struct iter {
25 /* this usually points to the list head */
26 void *data0;
27
28 /* these point to the list item, for simple lists data2 is usually NULL */
29 void *data1;
30 void *data2;
31 };
32
iter_init(struct iter * iter)33 static inline void iter_init(struct iter *iter)
34 {
35 iter->data0 = NULL;
36 iter->data1 = NULL;
37 iter->data2 = NULL;
38 }
39
iter_head(struct iter * iter)40 static inline void iter_head(struct iter *iter)
41 {
42 iter->data1 = NULL;
43 iter->data2 = NULL;
44 }
45
iters_equal(struct iter * a,struct iter * b)46 static inline int iters_equal(struct iter *a, struct iter *b)
47 {
48 return a->data0 == b->data0 &&
49 a->data1 == b->data1 &&
50 a->data2 == b->data2;
51 }
52
iter_is_head(struct iter * iter)53 static inline int iter_is_head(struct iter *iter)
54 {
55 return iter->data0 != NULL &&
56 iter->data1 == NULL &&
57 iter->data2 == NULL;
58 }
59
iter_is_null(struct iter * iter)60 static inline int iter_is_null(struct iter *iter)
61 {
62 return iter->data0 == NULL &&
63 iter->data1 == NULL &&
64 iter->data2 == NULL;
65 }
66
iter_is_empty(struct iter * iter)67 static inline int iter_is_empty(struct iter *iter)
68 {
69 return iter->data0 == NULL || (iter->data1 == NULL && iter->data2 == NULL);
70 }
71
72 #define GENERIC_ITER_PREV(FUNC, TYPE, MEMBER) \
73 int FUNC(struct iter *iter) \
74 { \
75 struct list_head *head = iter->data0; \
76 TYPE *e = iter->data1; \
77 \
78 if (head == NULL) \
79 return 0; \
80 if (e == NULL) { \
81 /* head, get last */ \
82 if (head->prev == head) { \
83 /* empty, iter points to the head already */ \
84 return 0; \
85 } \
86 iter->data1 = container_of(head->prev, TYPE, MEMBER); \
87 return 1; \
88 } \
89 if (e->MEMBER.prev == head) { \
90 iter->data1 = NULL; \
91 return 0; \
92 } \
93 iter->data1 = container_of(e->MEMBER.prev, TYPE, MEMBER); \
94 return 1; \
95 }
96
97 #define GENERIC_ITER_NEXT(FUNC, TYPE, MEMBER) \
98 int FUNC(struct iter *iter) \
99 { \
100 struct list_head *head = iter->data0; \
101 TYPE *e = iter->data1; \
102 \
103 if (head == NULL) \
104 return 0; \
105 if (e == NULL) { \
106 /* head, get first */ \
107 if (head->next == head) { \
108 /* empty, iter points to the head already */ \
109 return 0; \
110 } \
111 iter->data1 = container_of(head->next, TYPE, MEMBER); \
112 return 1; \
113 } \
114 if (e->MEMBER.next == head) { \
115 iter->data1 = NULL; \
116 return 0; \
117 } \
118 iter->data1 = container_of(e->MEMBER.next, TYPE, MEMBER); \
119 return 1; \
120 }
121
122 #define GENERIC_TREE_ITER_PREV(FUNC, TYPE, MEMBER) \
123 int FUNC(struct iter *iter) \
124 { \
125 struct rb_root *root = iter->data0; \
126 TYPE *e = iter->data1; \
127 \
128 if (root == NULL) \
129 return 0; \
130 if (e == NULL) { \
131 /* head, get last */ \
132 if (rb_root_empty(root)) { \
133 /* empty, iter points to the head already */ \
134 return 0; \
135 } \
136 iter->data1 = container_of(rb_last(root), TYPE, MEMBER); \
137 return 1; \
138 } \
139 if (rb_prev(&e->MEMBER) == NULL) { \
140 iter->data1 = NULL; \
141 return 0; \
142 } \
143 iter->data1 = container_of(rb_prev(&e->MEMBER), TYPE, MEMBER); \
144 return 1; \
145 }
146
147 #define GENERIC_TREE_ITER_NEXT(FUNC, TYPE, MEMBER) \
148 int FUNC(struct iter *iter) \
149 { \
150 struct rb_root *root = iter->data0; \
151 TYPE *e = iter->data1; \
152 \
153 if (root == NULL) \
154 return 0; \
155 if (e == NULL) { \
156 /* head, get first */ \
157 if (rb_root_empty(root)) { \
158 /* empty, iter points to the head already */ \
159 return 0; \
160 } \
161 iter->data1 = container_of(rb_first(root), TYPE, MEMBER); \
162 return 1; \
163 } \
164 if (rb_next(&e->MEMBER) == NULL) { \
165 iter->data1 = NULL; \
166 return 0; \
167 } \
168 iter->data1 = container_of(rb_next(&e->MEMBER), TYPE, MEMBER); \
169 return 1; \
170 }
171
172 #endif
173