view src/thread/pth/SDL_syscond.c @ 1000:fbeac9312843

TinyGL only support RGB24 color buffer
author Patrice Mandin <patmandin@gmail.com>
date Tue, 30 Nov 2004 16:14:05 +0000 (2004-11-30)
parents 1d74ddc90cb2
children 3692456e7b0f
line wrap: on
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/*
 *	GNU pth conditions variables
 *
 *	Patrice Mandin
 */

#include <stdio.h>
#include <stdlib.h>
#include <pth.h>

#include "SDL_error.h"
#include "SDL_thread.h"
#include "SDL_syscond_c.h"
#include "SDL_sysmutex_c.h"

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

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

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