1/* Generic associative array implementation.
2 *
3 * See Documentation/core-api/assoc_array.rst for information.
4 *
5 * Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
6 * Written by David Howells (dhowells@redhat.com)
7 *
8 * This program is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU General Public Licence
10 * as published by the Free Software Foundation; either version
11 * 2 of the Licence, or (at your option) any later version.
12 */
13
14#ifndef _LINUX_ASSOC_ARRAY_H
15#define _LINUX_ASSOC_ARRAY_H
16
17#ifdef CONFIG_ASSOCIATIVE_ARRAY
18
19#include <linux/types.h>
20
21#define ASSOC_ARRAY_KEY_CHUNK_SIZE BITS_PER_LONG /* Key data retrieved in chunks of this size */
22
23/*
24 * Generic associative array.
25 */
26struct assoc_array {
27 struct assoc_array_ptr *root; /* The node at the root of the tree */
28 unsigned long nr_leaves_on_tree;
29};
30
31/*
32 * Operations on objects and index keys for use by array manipulation routines.
33 */
34struct assoc_array_ops {
35 /* Method to get a chunk of an index key from caller-supplied data */
36 unsigned long (*get_key_chunk)(const void *index_key, int level);
37
38 /* Method to get a piece of an object's index key */
39 unsigned long (*get_object_key_chunk)(const void *object, int level);
40
41 /* Is this the object we're looking for? */
42 bool (*compare_object)(const void *object, const void *index_key);
43
44 /* How different is an object from an index key, to a bit position in
45 * their keys? (or -1 if they're the same)
46 */
47 int (*diff_objects)(const void *object, const void *index_key);
48
49 /* Method to free an object. */
50 void (*free_object)(void *object);
51};
52
53/*
54 * Access and manipulation functions.
55 */
56struct assoc_array_edit;
57
58static inline void assoc_array_init(struct assoc_array *array)
59{
60 array->root = NULL;
61 array->nr_leaves_on_tree = 0;
62}
63
64extern int assoc_array_iterate(const struct assoc_array *array,
65 int (*iterator)(const void *object,
66 void *iterator_data),
67 void *iterator_data);
68extern void *assoc_array_find(const struct assoc_array *array,
69 const struct assoc_array_ops *ops,
70 const void *index_key);
71extern void assoc_array_destroy(struct assoc_array *array,
72 const struct assoc_array_ops *ops);
73extern struct assoc_array_edit *assoc_array_insert(struct assoc_array *array,
74 const struct assoc_array_ops *ops,
75 const void *index_key,
76 void *object);
77extern void assoc_array_insert_set_object(struct assoc_array_edit *edit,
78 void *object);
79extern struct assoc_array_edit *assoc_array_delete(struct assoc_array *array,
80 const struct assoc_array_ops *ops,
81 const void *index_key);
82extern struct assoc_array_edit *assoc_array_clear(struct assoc_array *array,
83 const struct assoc_array_ops *ops);
84extern void assoc_array_apply_edit(struct assoc_array_edit *edit);
85extern void assoc_array_cancel_edit(struct assoc_array_edit *edit);
86extern int assoc_array_gc(struct assoc_array *array,
87 const struct assoc_array_ops *ops,
88 bool (*iterator)(void *object, void *iterator_data),
89 void *iterator_data);
90
91#endif /* CONFIG_ASSOCIATIVE_ARRAY */
92#endif /* _LINUX_ASSOC_ARRAY_H */
93