1 /* SPDX-License-Identifier: GPL-2.0-or-later */
2 /* Generic associative array implementation.
3 *
4 * See Documentation/core-api/assoc_array.rst for information.
5 *
6 * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
7 * Written by David Howells (dhowells@redhat.com)
8 */
9
10 #ifndef _LINUX_ASSOC_ARRAY_H
11 #define _LINUX_ASSOC_ARRAY_H
12
13 #ifdef CONFIG_ASSOCIATIVE_ARRAY
14
15 #include <linux/types.h>
16
17 #define ASSOC_ARRAY_KEY_CHUNK_SIZE BITS_PER_LONG /* Key data retrieved in chunks of this size */
18
19 /*
20 * Generic associative array.
21 */
22 struct assoc_array {
23 struct assoc_array_ptr *root; /* The node at the root of the tree */
24 unsigned long nr_leaves_on_tree;
25 };
26
27 /*
28 * Operations on objects and index keys for use by array manipulation routines.
29 */
30 struct assoc_array_ops {
31 /* Method to get a chunk of an index key from caller-supplied data */
32 unsigned long (*get_key_chunk)(const void *index_key, int level);
33
34 /* Method to get a piece of an object's index key */
35 unsigned long (*get_object_key_chunk)(const void *object, int level);
36
37 /* Is this the object we're looking for? */
38 bool (*compare_object)(const void *object, const void *index_key);
39
40 /* How different is an object from an index key, to a bit position in
41 * their keys? (or -1 if they're the same)
42 */
43 int (*diff_objects)(const void *object, const void *index_key);
44
45 /* Method to free an object. */
46 void (*free_object)(void *object);
47 };
48
49 /*
50 * Access and manipulation functions.
51 */
52 struct assoc_array_edit;
53
54 static inline void assoc_array_init(struct assoc_array *array)
55 {
56 array->root = NULL;
57 array->nr_leaves_on_tree = 0;
58 }
59
60 extern int assoc_array_iterate(const struct assoc_array *array,
61 int (*iterator)(const void *object,
62 void *iterator_data),
63 void *iterator_data);
64 extern void *assoc_array_find(const struct assoc_array *array,
65 const struct assoc_array_ops *ops,
66 const void *index_key);
67 extern void assoc_array_destroy(struct assoc_array *array,
68 const struct assoc_array_ops *ops);
69 extern struct assoc_array_edit *assoc_array_insert(struct assoc_array *array,
70 const struct assoc_array_ops *ops,
71 const void *index_key,
72 void *object);
73 extern void assoc_array_insert_set_object(struct assoc_array_edit *edit,
74 void *object);
75 extern struct assoc_array_edit *assoc_array_delete(struct assoc_array *array,
76 const struct assoc_array_ops *ops,
77 const void *index_key);
78 extern struct assoc_array_edit *assoc_array_clear(struct assoc_array *array,
79 const struct assoc_array_ops *ops);
80 extern void assoc_array_apply_edit(struct assoc_array_edit *edit);
81 extern void assoc_array_cancel_edit(struct assoc_array_edit *edit);
82 extern int assoc_array_gc(struct assoc_array *array,
83 const struct assoc_array_ops *ops,
84 bool (*iterator)(void *object, void *iterator_data),
85 void *iterator_data);
86
87 #endif /* CONFIG_ASSOCIATIVE_ARRAY */
88 #endif /* _LINUX_ASSOC_ARRAY_H */
89
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