/* Generic associative array implementation.
*
* See Documentation/assoc_array.txt for information.
*
* Copyright (C) 2013 Red Hat, Inc. All Rights Reserved.
* Written by David Howells ([email protected])
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public Licence
* as published by the Free Software Foundation; either version
* 2 of the Licence, or (at your option) any later version.
*/

#ifndef _LINUX_ASSOC_ARRAY_H
#define _LINUX_ASSOC_ARRAY_H

#ifdef CONFIG_ASSOCIATIVE_ARRAY

#include <linux/types.h>

#define ASSOC_ARRAY_KEY_CHUNK_SIZE BITS_PER_LONG /* Key data retrieved in chunks of this size */

/*
* Generic associative array.
*/
struct assoc_array {
struct assoc_array_ptr *root; /* The node at the root of the tree */
unsigned long nr_leaves_on_tree;
};

/*
* Operations on objects and index keys for use by array manipulation routines.
*/
struct assoc_array_ops {
/* Method to get a chunk of an index key from caller-supplied data */
unsigned long (*get_key_chunk)(const void *index_key, int level);

/* Method to get a piece of an object's index key */
unsigned long (*get_object_key_chunk)(const void *object, int level);

/* Is this the object we're looking for? */
bool (*compare_object)(const void *object, const void *index_key);

/* How different is an object from an index key, to a bit position in
* their keys? (or -1 if they're the same)
*/
int (*diff_objects)(const void *object, const void *index_key);

/* Method to free an object. */
void (*free_object)(void *object);
};

/*
* Access and manipulation functions.
*/
struct assoc_array_edit;

static inline void assoc_array_init(struct assoc_array *array)
{
array->root = NULL;
array->nr_leaves_on_tree = 0;
}

extern int assoc_array_iterate(const struct assoc_array *array,
int (*iterator)(const void *object,
void *iterator_data),
void *iterator_data);
extern void *assoc_array_find(const struct assoc_array *array,
const struct assoc_array_ops *ops,
const void *index_key);
extern void assoc_array_destroy(struct assoc_array *array,
const struct assoc_array_ops *ops);
extern struct assoc_array_edit *assoc_array_insert(struct assoc_array *array,
const struct assoc_array_ops *ops,
const void *index_key,
void *object);
extern void assoc_array_insert_set_object(struct assoc_array_edit *edit,
void *object);
extern struct assoc_array_edit *assoc_array_delete(struct assoc_array *array,
const struct assoc_array_ops *ops,
const void *index_key);
extern struct assoc_array_edit *assoc_array_clear(struct assoc_array *array,
const struct assoc_array_ops *ops);
extern void assoc_array_apply_edit(struct assoc_array_edit *edit);
extern void assoc_array_cancel_edit(struct assoc_array_edit *edit);
extern int assoc_array_gc(struct assoc_array *array,
const struct assoc_array_ops *ops,
bool (*iterator)(void *object, void *iterator_data),
void *iterator_data);

#endif /* CONFIG_ASSOCIATIVE_ARRAY */
#endif /* _LINUX_ASSOC_ARRAY_H */