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#include <cutils/atomic.h>
24
25__BEGIN_DECLS
26
27#define AREF_TO_ITEM(aref, container, member) \
28    (container *) (((char*) (aref)) - offsetof(container, member))
29
30struct aref
31{
32    volatile int32_t count;
33};
34
35static inline void aref_init(struct aref *r)
36{
37    r->count = 1;
38}
39
40static inline int32_t aref_count(struct aref *r)
41{
42    return r->count;
43}
44
45static inline void aref_get(struct aref *r)
46{
47    android_atomic_inc(&r->count);
48}
49
50static inline void aref_put(struct aref *r, void (*release)(struct aref *))
51{
52    if (android_atomic_dec(&r->count) == 1)
53        release(r);
54}
55
56__END_DECLS
57
58#endif // _CUTILS_AREF_H_
59