include/linux/assoc_array.h

   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 */