/*

    SDL - Simple DirectMedia Layer

    Copyright (C) 1997-2006 Sam Lantinga

    This library is free software; you can redistribute it and/or

    modify it under the terms of the GNU Lesser General Public

    License as published by the Free Software Foundation; either

    version 2.1 of the License, or (at your option) any later version.

    This library 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

    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public

    License along with this library; if not, write to the Free Software

    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga

    slouken@libsdl.org

*/

#include "SDL_config.h"

/* Semaphores in the BeOS environment */

#include <be/kernel/OS.h>

#include "SDL_thread.h"

struct SDL_semaphore {

	sem_id id;

};

/* Create a counting semaphore */

SDL_sem *SDL_CreateSemaphore(Uint32 initial_value)

{

	SDL_sem *sem;

	sem = (SDL_sem *)SDL_malloc(sizeof(*sem));

	if ( sem ) {

		sem->id = create_sem(initial_value, "SDL semaphore");

		if ( sem->id < B_NO_ERROR ) {

			SDL_SetError("create_sem() failed");

			SDL_free(sem);

			sem = NULL;

		}

	} else {

		SDL_OutOfMemory();

	}

	return(sem);

}

/* Free the semaphore */

void SDL_DestroySemaphore(SDL_sem *sem)

{

	if ( sem ) {

		if ( sem->id >= B_NO_ERROR ) {

			delete_sem(sem->id);

		}

		SDL_free(sem);

	}

}

int SDL_SemWaitTimeout(SDL_sem *sem, Uint32 timeout)

{

	int32 val;

	int retval;

	if ( ! sem ) {

		SDL_SetError("Passed a NULL semaphore");

		return -1;

	}

  tryagain:

	if ( timeout == SDL_MUTEX_MAXWAIT ) {

		val = acquire_sem(sem->id);

	} else {

		timeout *= 1000; /* BeOS uses a timeout in microseconds */

		val = acquire_sem_etc(sem->id, 1, B_RELATIVE_TIMEOUT, timeout);

	}

	switch (val) {

	    case B_INTERRUPTED:

		goto tryagain;

	    case B_NO_ERROR:

		retval = 0;

		break;

	    case B_TIMED_OUT:

		retval = SDL_MUTEX_TIMEDOUT;

		break;

	    case B_WOULD_BLOCK:

		retval = SDL_MUTEX_TIMEDOUT;

		break;

	    default:

		SDL_SetError("acquire_sem() failed");

		retval = -1;

		break;

	}

	return retval;

}

int SDL_SemTryWait(SDL_sem *sem)

{

	return SDL_SemWaitTimeout(sem, 0);

}

int SDL_SemWait(SDL_sem *sem)

{

	return SDL_SemWaitTimeout(sem, SDL_MUTEX_MAXWAIT);

}

/* Returns the current count of the semaphore */

Uint32 SDL_SemValue(SDL_sem *sem)

{

	int32 count;

	Uint32 value;

	value = 0;

	if ( sem ) {

		get_sem_count(sem->id, &count);

		if ( count > 0 ) {

			value = (Uint32)count;

		}

	}

	return value;

}

/* Atomically increases the semaphore's count (not blocking) */

int SDL_SemPost(SDL_sem *sem)

{

	if ( ! sem ) {

		SDL_SetError("Passed a NULL semaphore");

		return -1;

	}

	if ( release_sem(sem->id) != B_NO_ERROR ) {

		SDL_SetError("release_sem() failed");

		return -1;

	}

	return 0;

}