artvertiser/FProfiler/FSemaphore.h

   1 /*
   2  *  FSemaphore.h
   3  *  F
   4  *
   5  *  Created by damian on 25/5/08.
   6  *  Copyright 2008 frey damian@frey.co.nz. All rights reserved.
   7  *
   8  */
   9
  10 #ifndef _FSEMAPHORE_H
  11 #define _FSEMAPHORE_H
  12
  13 #include <stdio.h>
  14 #include <semaphore.h>
  15 #include <pthread.h>
  16 #include <sys/errno.h>
  17 #include <assert.h>
  18
  19 class FBarrier
  20 {
  21 public:
  22     /// count is the number of threads to wait for.
  23     FBarrier( int count ) { int res = pthread_barrier_init( &barrier, 0, count ); assert(res==0 && "error creating barrier"); }
  24     ~FBarrier() { int res = pthread_barrier_destroy( &barrier ); if ( res==EBUSY ) assert(false && "cannot destroy barrier when it is in use" ); }
  25
  26     /// wait for everyone to arrive at the barrier. return once they have. returns true if wait returns
  27     /// the PTHREAD_BARRIER_SERIAL_THREAD return value.
  28     bool Wait() { int ret = pthread_barrier_wait( &barrier ); return ret == PTHREAD_BARRIER_SERIAL_THREAD; }
  29
  30 private:
  31
  32     pthread_barrier_t barrier;
  33
  34 };
  35
  36 class FSemaphore
  37 {
  38 public:
  39         FSemaphore( int init = 1,bool _debug = false) { debug = _debug; sem_init( &sem, 0, init ); }
  40         ~FSemaphore() { sem_destroy( &sem ); }
  41
  42         /// wait for the semaphore to become available and then grab
  43         void Wait() { if ( debug ) printf("%x about to Wait\n", (unsigned int)&sem ); sem_wait( &sem ); if( debug ) printf("%x Wait\n", (unsigned int)&sem ); }
  44
  45         /// try once; if available, grab and return true, else return false
  46         bool TryWait() {
  47                 /*#ifdef DEBUG
  48                 int err=sem_trywait( &sem );
  49                 if ( err != 0 )
  50                 Log::Msg( "trywait: error %s\n", err == EAGAIN? "EAGAIN" :
  51                                   (err==EDEADLK?"EDEADLK":(err==EINTR?"EINTR":(err==EINVAL?"EINVAL":"UNKNOWN"))));
  52                 return ( err == 0 );
  53 #else*/
  54                 if ( debug ) printf( "%x Trywait\n", (unsigned int)&sem );
  55                 return 0==sem_trywait( &sem );
  56                 //#endif
  57         }
  58
  59         /// signal the semaphore that we've finished
  60         void Signal() { if (debug) printf("%x Signal\n", (unsigned int)&sem); sem_post( &sem );  }
  61
  62 private:
  63         sem_t sem;
  64         bool debug;
  65 };
  66
  67
  68 #endif