Alex Ray | d874cc8 | 2013-01-09 18:13:28 -0800 | [diff] [blame] | 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 | |
| 34 | struct aref |
| 35 | { |
| 36 | volatile int32_t count; |
| 37 | }; |
| 38 | |
| 39 | static inline void aref_init(struct aref *r) |
| 40 | { |
| 41 | r->count = 1; |
| 42 | } |
| 43 | |
| 44 | static inline int32_t aref_count(struct aref *r) |
| 45 | { |
| 46 | return r->count; |
| 47 | } |
| 48 | |
| 49 | static inline void aref_get(struct aref *r) |
| 50 | { |
| 51 | android_atomic_inc(&r->count); |
| 52 | } |
| 53 | |
| 54 | static 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_ |