src/thread/pth/SDL_syscond.c
author Sam Lantinga <slouken@libsdl.org>
Thu, 24 Dec 2009 19:16:08 +0000
changeset 3598 427ff6d745df
parent 2859 99210400e8b9
permissions -rw-r--r--
Added rectangle test

/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 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"

/*
 *	GNU pth conditions variables
 *
 *	Patrice Mandin
 */

#include <pth.h>

#include "SDL_thread.h"
#include "SDL_sysmutex_c.h"

struct SDL_cond
{
    pth_cond_t condpth_p;
};

/* Create a condition variable */
SDL_cond *
SDL_CreateCond(void)
{
    SDL_cond *cond;

    cond = (SDL_cond *) SDL_malloc(sizeof(SDL_cond));
    if (cond) {
        if (pth_cond_init(&(cond->condpth_p)) < 0) {
            SDL_SetError("pthread_cond_init() failed");
            SDL_free(cond);
            cond = NULL;
        }
    } else {
        SDL_OutOfMemory();
    }
    return (cond);
}

/* Destroy a condition variable */
void
SDL_DestroyCond(SDL_cond * cond)
{
    if (cond) {
        SDL_free(cond);
    }
}

/* Restart one of the threads that are waiting on the condition variable */
int
SDL_CondSignal(SDL_cond * cond)
{
    int retval;

    if (!cond) {
        SDL_SetError("Passed a NULL condition variable");
        return -1;
    }

    retval = 0;
    if (pth_cond_notify(&(cond->condpth_p), FALSE) != 0) {
        SDL_SetError("pth_cond_notify() failed");
        retval = -1;
    }
    return retval;
}

/* Restart all threads that are waiting on the condition variable */
int
SDL_CondBroadcast(SDL_cond * cond)
{
    int retval;

    if (!cond) {
        SDL_SetError("Passed a NULL condition variable");
        return -1;
    }

    retval = 0;
    if (pth_cond_notify(&(cond->condpth_p), TRUE) != 0) {
        SDL_SetError("pth_cond_notify() failed");
        retval = -1;
    }
    return retval;
}

/* Wait on the condition variable for at most 'ms' milliseconds.
   The mutex must be locked before entering this function!
   The mutex is unlocked during the wait, and locked again after the wait.

Typical use:

Thread A:
	SDL_LockMutex(lock);
	while ( ! condition ) {
		SDL_CondWait(cond);
	}
	SDL_UnlockMutex(lock);

Thread B:
	SDL_LockMutex(lock);
	...
	condition = true;
	...
	SDL_UnlockMutex(lock);
 */
int
SDL_CondWaitTimeout(SDL_cond * cond, SDL_mutex * mutex, Uint32 ms)
{
    int retval;
    pth_event_t ev;
    int sec;

    if (!cond) {
        SDL_SetError("Passed a NULL condition variable");
        return -1;
    }

    retval = 0;

    sec = ms / 1000;
    ev = pth_event(PTH_EVENT_TIME,
                   pth_timeout(sec, (ms - sec * 1000) * 1000));

    if (pth_cond_await(&(cond->condpth_p), &(mutex->mutexpth_p), ev) != 0) {
        SDL_SetError("pth_cond_await() failed");
        retval = -1;
    }

    pth_event_free(ev, PTH_FREE_ALL);

    return retval;
}

/* Wait on the condition variable forever */
int
SDL_CondWait(SDL_cond * cond, SDL_mutex * mutex)
{
    int retval;

    if (!cond) {
        SDL_SetError("Passed a NULL condition variable");
        return -1;
    }

    retval = 0;
    if (pth_cond_await(&(cond->condpth_p), &(mutex->mutexpth_p), NULL) != 0) {
        SDL_SetError("pth_cond_await() failed");
        retval = -1;
    }
    return retval;
}

/* vi: set ts=4 sw=4 expandtab: */