www.pudn.com > MP3CORD.rar > semaphore.cpp

/*____________________________________________________________________________ 
	 
	FreeAmp - The Free MP3 Player 
 
	Portions Copyright (C) 1998-1999 EMusic.com 
 
	This program is free software; you can redistribute it and/or modify 
	it under the terms of the GNU General Public License as published by 
	the Free Software Foundation; either version 2 of the License, or 
	(at your option) any later version. 
 
	This program is distributed in the hope that it will be useful, 
	but WITHOUT ANY WARRANTY; without even the implied warranty of 
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the 
	GNU General Public License for more details. 
 
	You should have received a copy of the GNU General Public License 
	along with this program; if not, write to the Free Software 
	Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 
	 
	$Id: semaphore.cpp,v 1.4 1999/12/10 07:16:40 elrod Exp $ 
____________________________________________________________________________*/ 
 
 
#include "config.h" 
 
#define DEBUG 0 
#include  
#include  
#include  
#include  
#include  
#include  
 
#include "semaphore.h" 
 
#define SEM_DEBUG 0 
 
Semaphore::Semaphore( int cnt ) 
:	count( cnt - 1 ) 
{ 
	if ( ( mutex = create_sem( count, "Semaphore" ) ) < B_NO_ERROR ) 
	{ 
		perror( "error creating semaphore" ); 
	} 
	PRINT(( "Semaphore ctor success, sem_id(%d), count(%d)\n", mutex, count )); 
} 
 
Semaphore::Semaphore( const char* name, int cnt ) 
:	count( cnt - 1 ) 
{ 
	if ( ( mutex = create_sem( count, name ) ) < B_NO_ERROR ) 
	{ 
		perror( "error creating semaphore" ); 
	} 
} 
 
Semaphore::~Semaphore() 
{ 
	if ( delete_sem( mutex ) < B_NO_ERROR ) 
	{ 
		perror( "Semaphore: couldn't delete semaphore" ); 
	} 
} 
 
void Semaphore::Wait() 
{ 
	status_t	err; 
#if SEM_DEBUG 
	int32		tc; 
	get_sem_count( mutex, &tc ); 
	PRINT(( "Semaphore::Wait:id(%d):count(%d)\n", mutex, tc )); 
#endif 
	if ( ( err = acquire_sem( mutex ) ) < B_NO_ERROR ) 
	{ 
		puts( "Sem::Wait:couldn't acquire sem" ); 
		DEBUGGER(( "Semaphore::Wait: couldn't acquire sem : %s\n", 
					strerror( err ) )); 
	} 
#if SEM_DEBUG 
	get_sem_count( mutex, &tc ); 
	PRINT(( "Semaphore::Wait:id(%d):count(%d) done\n", mutex, tc )); 
#endif 
} 
 
bool Semaphore::Wait( long timeout ) 
{ 
	status_t	stat; 
 
	if ( timeout == WAIT_FOREVER ) 
	{ 
		stat = acquire_sem( mutex ); 
	} 
	else 
	{ 
		stat = acquire_sem_etc( mutex, 1, B_TIMEOUT, (bigtime_t)(timeout * 1e6) ); 
	} 
 
	return( stat == B_NO_ERROR ); 
} 
 
void Semaphore::Signal() 
{ 
	status_t	err; 
#if SEM_DEBUG 
	int32		tc; 
	get_sem_count( mutex, &tc ); 
	PRINT(( "Semaphore::Signal:id(%d):count(%d)\n", mutex, tc )); 
#endif 
	if ( ( err = release_sem( mutex ) ) < B_NO_ERROR ) 
	{ 
		puts( "Sem::Signal:couldn't acquire sem" ); 
		DEBUGGER(( "Semaphore::Signal: couldn't release sem : %s\n", 
					strerror( err ) )); 
	} 
#if SEM_DEBUG 
	get_sem_count( mutex, &tc ); 
	PRINT(( "Semaphore::Signal:id(%d):count(%d) done\n", mutex, tc )); 
#endif 
}