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      1 /*
      2  * Copyright (C) 2012 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License"); you may not
      5  * use this file except in compliance with the License. You may obtain a copy of
      6  * 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, WITHOUT
     12  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
     13  * License for the specific language governing permissions and limitations under
     14  * the License.
     15  */
     16 
     17 #include "Semaphore.h"
     18 
     19 
     20 Semaphore::Semaphore(int count)
     21 {
     22     if (sem_init(&mSem, 0, count) != 0) {
     23         ASSERT(false);
     24     }
     25 }
     26 
     27 Semaphore::~Semaphore()
     28 {
     29     sem_destroy(&mSem);
     30 }
     31 
     32 void Semaphore::tryWait()
     33 {
     34     sem_trywait(&mSem);
     35 }
     36 
     37 bool Semaphore::wait()
     38 {
     39     if (sem_wait(&mSem) == 0) {
     40         return true;
     41     } else {
     42         return false;
     43     }
     44 }
     45 
     46 bool Semaphore::timedWait(int timeInMSec)
     47 {
     48     const int ONE_SEC_IN_NANOSEC = 1000000000;
     49     const int ONE_MSEC_IN_NANOSEC = 1000000;
     50     const int ONE_SEC_IN_MSEC = 1000;
     51     struct timespec timeOld;
     52     if (clock_gettime(CLOCK_REALTIME, &timeOld) != 0) {
     53             return false;
     54     }
     55     int secToGo = timeInMSec / ONE_SEC_IN_MSEC;
     56     int msecToGo = timeInMSec - (ONE_SEC_IN_MSEC * secToGo);
     57     int nanoSecToGo = ONE_MSEC_IN_NANOSEC * msecToGo;
     58     struct timespec timeNew = timeOld;
     59     int nanoTotal = timeOld.tv_nsec + nanoSecToGo;
     60     //LOGI("secToGo %d, msecToGo %d, nanoTotal %d", secToGo, msecToGo, nanoTotal);
     61     if (nanoTotal > ONE_SEC_IN_NANOSEC) {
     62         nanoTotal -= ONE_SEC_IN_NANOSEC;
     63         secToGo += 1;
     64     }
     65     timeNew.tv_sec += secToGo;
     66     timeNew.tv_nsec = nanoTotal;
     67     //LOGV("Semaphore::timedWait now %d-%d until %d-%d for %d msecs",
     68     //        timeOld.tv_sec, timeOld.tv_nsec, timeNew.tv_sec, timeNew.tv_nsec, timeInMSec);
     69     if (sem_timedwait(&mSem, &timeNew) == 0) {
     70         return true;
     71     } else {
     72         return false;
     73     }
     74 }
     75 
     76 void Semaphore::post()
     77 {
     78     sem_post(&mSem);
     79 }
     80