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