1/*
2 * Copyright (c) 2011 Intel Corporation.  All rights reserved.
3 *
4 * This software is available to you under a choice of one of two
5 * licenses.  You may choose to be licensed under the terms of the GNU
6 * General Public License (GPL) Version 2, available from the file
7 * COPYING in the main directory of this source tree, or the
8 * OpenIB.org BSD license below:
9 *
10 *     Redistribution and use in source and binary forms, with or
11 *     without modification, are permitted provided that the following
12 *     conditions are met:
13 *
14 *      - Redistributions of source code must retain the above
15 *        copyright notice, this list of conditions and the following
16 *        disclaimer.
17 *
18 *      - Redistributions in binary form must reproduce the above
19 *        copyright notice, this list of conditions and the following
20 *        disclaimer in the documentation and/or other materials
21 *        provided with the distribution.
22 *
23 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
24 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
25 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
26 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
27 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
28 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
29 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
30 * SOFTWARE.
31 *
32 */
33
34#if !defined(INDEXER_H)
35#define INDEXER_H
36
37#include <config.h>
38#include <stddef.h>
39#include <sys/types.h>
40
41/*
42 * Indexer - to find a structure given an index.  Synchronization
43 * must be provided by the caller.  Caller must initialize the
44 * indexer by setting free_list and size to 0.
45 */
46
47union idx_entry {
48	void *item;
49	int   next;
50};
51
52#define IDX_INDEX_BITS 16
53#define IDX_ENTRY_BITS 10
54#define IDX_ENTRY_SIZE (1 << IDX_ENTRY_BITS)
55#define IDX_ARRAY_SIZE (1 << (IDX_INDEX_BITS - IDX_ENTRY_BITS))
56#define IDX_MAX_INDEX  ((1 << IDX_INDEX_BITS) - 1)
57
58struct indexer
59{
60	union idx_entry *array[IDX_ARRAY_SIZE];
61	int		 free_list;
62	int		 size;
63};
64
65#define idx_array_index(index) (index >> IDX_ENTRY_BITS)
66#define idx_entry_index(index) (index & (IDX_ENTRY_SIZE - 1))
67
68int idx_insert(struct indexer *idx, void *item);
69void *idx_remove(struct indexer *idx, int index);
70void idx_replace(struct indexer *idx, int index, void *item);
71
72static inline void *idx_at(struct indexer *idx, int index)
73{
74	return (idx->array[idx_array_index(index)] + idx_entry_index(index))->item;
75}
76
77/*
78 * Index map - associates a structure with an index.  Synchronization
79 * must be provided by the caller.  Caller must initialize the
80 * index map by setting it to 0.
81 */
82
83struct index_map
84{
85	void **array[IDX_ARRAY_SIZE];
86};
87
88int idm_set(struct index_map *idm, int index, void *item);
89void *idm_clear(struct index_map *idm, int index);
90
91static inline void *idm_at(struct index_map *idm, int index)
92{
93	void **entry;
94	entry = idm->array[idx_array_index(index)];
95	return entry[idx_entry_index(index)];
96}
97
98static inline void *idm_lookup(struct index_map *idm, int index)
99{
100	return ((index <= IDX_MAX_INDEX) && idm->array[idx_array_index(index)]) ?
101		idm_at(idm, index) : NULL;
102}
103
104typedef struct _dlist_entry {
105	struct _dlist_entry	*next;
106	struct _dlist_entry	*prev;
107}	dlist_entry;
108
109static inline void dlist_init(dlist_entry *head)
110{
111	head->next = head;
112	head->prev = head;
113}
114
115static inline int dlist_empty(dlist_entry *head)
116{
117	return head->next == head;
118}
119
120static inline void dlist_insert_after(dlist_entry *item, dlist_entry *head)
121{
122	item->next = head->next;
123	item->prev = head;
124	head->next->prev = item;
125	head->next = item;
126}
127
128static inline void dlist_insert_before(dlist_entry *item, dlist_entry *head)
129{
130	dlist_insert_after(item, head->prev);
131}
132
133#define dlist_insert_head dlist_insert_after
134#define dlist_insert_tail dlist_insert_before
135
136static inline void dlist_remove(dlist_entry *item)
137{
138	item->prev->next = item->next;
139	item->next->prev = item->prev;
140}
141
142#endif /* INDEXER_H */
143