common/SC_Sem.cpp

   1 /*
   2         SuperCollider real time audio synthesis system
   3     Copyright (c) 2002 James McCartney. All rights reserved.
   4         http://www.audiosynth.com
   5
   6     This program is free software; you can redistribute it and/or modify
   7     it under the terms of the GNU General Public License as published by
   8     the Free Software Foundation; either version 2 of the License, or
   9     (at your option) any later version.
  10
  11     This program is distributed in the hope that it will be useful,
  12     but WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14     GNU General Public License for more details.
  15
  16     You should have received a copy of the GNU General Public License
  17     along with this program; if not, write to the Free Software
  18     Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301  USA
  19 */
  20
  21
  22 #include "SC_Sem.h"
  23
  24 SC_Semaphore::SC_Semaphore(int initialCount)
  25 {
  26         pthread_mutex_init (&mutex, NULL);
  27         pthread_cond_init (&available, NULL);
  28         count = initialCount;
  29 }
  30
  31 SC_Semaphore::~SC_Semaphore()
  32 {
  33         pthread_mutex_destroy (&mutex);
  34         pthread_cond_destroy (&available);
  35 }
  36
  37 void SC_Semaphore::Acquire()
  38 {
  39         pthread_mutex_lock (&mutex);
  40         while (count < 1) {
  41                 pthread_cond_wait (&available, &mutex);
  42         }
  43         count--;
  44         pthread_mutex_unlock (&mutex);
  45
  46 }
  47
  48 void SC_Semaphore::Release()
  49 {
  50         pthread_mutex_lock (&mutex);
  51         if (++count > 0) {
  52                 pthread_cond_signal (&available);
  53         }
  54         pthread_mutex_unlock (&mutex);
  55 }
  56