1/*
2 * Copyright (C) 2013 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#ifndef _CUTILS_AREF_H_
18#define _CUTILS_AREF_H_
19
20#include <stddef.h>
21#include <sys/cdefs.h>
22
23#ifdef ANDROID_SMP
24#include <cutils/atomic-inline.h>
25#else
26#include <cutils/atomic.h>
27#endif
28
29__BEGIN_DECLS
30
31#define AREF_TO_ITEM(aref, container, member) \
32    (container *) (((char*) (aref)) - offsetof(container, member))
33
34struct aref
35{
36    volatile int32_t count;
37};
38
39static inline void aref_init(struct aref *r)
40{
41    r->count = 1;
42}
43
44static inline int32_t aref_count(struct aref *r)
45{
46    return r->count;
47}
48
49static inline void aref_get(struct aref *r)
50{
51    android_atomic_inc(&r->count);
52}
53
54static inline void aref_put(struct aref *r, void (*release)(struct aref *))
55{
56    if (android_atomic_dec(&r->count) == 1)
57        release(r);
58}
59
60__END_DECLS
61
62#endif // _CUTILS_AREF_H_
63