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_ 63
