LXR linux/include/linux/assoc

   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 */
  22struct 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 */
  30struct 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 */
  52struct assoc_array_edit;
  53
  54static inline void assoc_array_init(struct assoc_array *array)
  55{
  56        array->root = NULL;
  57        array->nr_leaves_on_tree = 0;
  58}
  59
  60extern int assoc_array_iterate(const struct assoc_array *array,
  61                               int (*iterator)(const void *object,
  62                                               void *iterator_data),
  63                               void *iterator_data);
  64extern void *assoc_array_find(const struct assoc_array *array,
  65                              const struct assoc_array_ops *ops,
  66                              const void *index_key);
  67extern void assoc_array_destroy(struct assoc_array *array,
  68                                const struct assoc_array_ops *ops);
  69extern 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);
  73extern void assoc_array_insert_set_object(struct assoc_array_edit *edit,
  74                                          void *object);
  75extern struct assoc_array_edit *assoc_array_delete(struct assoc_array *array,
  76                                                   const struct assoc_array_ops *ops,
  77                                                   const void *index_key);
  78extern struct assoc_array_edit *assoc_array_clear(struct assoc_array *array,
  79                                                  const struct assoc_array_ops *ops);
  80extern void assoc_array_apply_edit(struct assoc_array_edit *edit);
  81extern void assoc_array_cancel_edit(struct assoc_array_edit *edit);
  82extern 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