00001
00002 #ifndef __semaphore_hpp__
00003 #define __semaphore_hpp__
00004
00005 #include <pthread.h>
00006
00007 class Semaphore
00008 {
00009 public:
00010 Semaphore( int value = 0 ) {
00011 pthread_mutex_init( &_mutex, NULL );
00012 pthread_cond_init( &_cond, NULL );
00013 _count = value;
00014 }
00015
00016 ~Semaphore() {
00017 pthread_mutex_destroy( &_mutex );
00018 pthread_cond_destroy( &_cond );
00019 }
00020
00021 int value() { return _count; }
00022
00023 void up() {
00024 pthread_mutex_lock( &_mutex );
00025 _count++;
00026 pthread_cond_signal( &_cond );
00027 pthread_mutex_unlock( &_mutex );
00028 }
00029
00030 void down() {
00031 pthread_mutex_lock( &_mutex );
00032 if( _count == 0 )
00033 pthread_cond_wait( &_cond, &_mutex );
00034 _count--;
00035 pthread_mutex_unlock( &_mutex );
00036 }
00037 private:
00038 pthread_mutex_t _mutex;
00039 pthread_cond_t _cond;
00040 int _count;
00041 };
00042
00043 #endif // __semaphore_hpp__
