include/linux/assoc_array.h

   1 /* Generic associative array implementation.
   2  *
   3  * See Documentation/assoc_array.txt 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  */
  26 struct 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  */
  34 struct 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  */
  56 struct assoc_array_edit;
  57
  58 static inline void assoc_array_init(struct assoc_array *array)
  59 {
  60         array->root = NULL;
  61         array->nr_leaves_on_tree = 0;
  62 }
  63
  64 extern int assoc_array_iterate(const struct assoc_array *array,
  65                                int (*iterator)(const void *object,
  66                                                void *iterator_data),
  67                                void *iterator_data);
  68 extern void *assoc_array_find(const struct assoc_array *array,
  69                               const struct assoc_array_ops *ops,
  70                               const void *index_key);
  71 extern void assoc_array_destroy(struct assoc_array *array,
  72                                 const struct assoc_array_ops *ops);
  73 extern 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);
  77 extern void assoc_array_insert_set_object(struct assoc_array_edit *edit,
  78                                           void *object);
  79 extern struct assoc_array_edit *assoc_array_delete(struct assoc_array *array,
  80                                                    const struct assoc_array_ops *ops,
  81                                                    const void *index_key);
  82 extern struct assoc_array_edit *assoc_array_clear(struct assoc_array *array,
  83                                                   const struct assoc_array_ops *ops);
  84 extern void assoc_array_apply_edit(struct assoc_array_edit *edit);
  85 extern void assoc_array_cancel_edit(struct assoc_array_edit *edit);
  86 extern 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 */