SDL_syscond.c
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/*
SDL - Simple DirectMedia Layer
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Copyright (C) 1997-2009 Sam Lantinga
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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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
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Lesser General Public License for more details.
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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
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Sam Lantinga
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slouken@libsdl.org
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*/
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#include "SDL_config.h"
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#include <sys/time.h>
#include <unistd.h>
#include <errno.h>
#include <pthread.h>
#include "SDL_thread.h"
#include "SDL_sysmutex_c.h"
struct SDL_cond
{
pthread_cond_t cond;
};
/* Create a condition variable */
SDL_cond * SDL_CreateCond(void)
{
SDL_cond *cond;
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cond = (SDL_cond *) SDL_malloc(sizeof(SDL_cond));
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if ( cond ) {
if ( pthread_cond_init(&cond->cond, NULL) < 0 ) {
SDL_SetError("pthread_cond_init() failed");
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SDL_free(cond);
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cond = NULL;
}
}
return(cond);
}
/* Destroy a condition variable */
void SDL_DestroyCond(SDL_cond *cond)
{
if ( cond ) {
pthread_cond_destroy(&cond->cond);
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SDL_free(cond);
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}
}
/* 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 ( pthread_cond_signal(&cond->cond) != 0 ) {
SDL_SetError("pthread_cond_signal() 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 ( pthread_cond_broadcast(&cond->cond) != 0 ) {
SDL_SetError("pthread_cond_broadcast() failed");
retval = -1;
}
return retval;
}
int SDL_CondWaitTimeout(SDL_cond *cond, SDL_mutex *mutex, Uint32 ms)
{
int retval;
struct timeval delta;
struct timespec abstime;
if ( ! cond ) {
SDL_SetError("Passed a NULL condition variable");
return -1;
}
gettimeofday(&delta, NULL);
abstime.tv_sec = delta.tv_sec + (ms/1000);
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abstime.tv_nsec = (delta.tv_usec + (ms%1000) * 1000) * 1000;
if ( abstime.tv_nsec > 1000000000 ) {
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abstime.tv_sec += 1;
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abstime.tv_nsec -= 1000000000;
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}
tryagain:
retval = pthread_cond_timedwait(&cond->cond, &mutex->id, &abstime);
switch (retval) {
case EINTR:
goto tryagain;
break;
case ETIMEDOUT:
retval = SDL_MUTEX_TIMEDOUT;
break;
case 0:
break;
default:
SDL_SetError("pthread_cond_timedwait() failed");
retval = -1;
break;
}
return retval;
}
/* Wait on the condition variable, unlocking the provided mutex.
The mutex must be locked before entering this function!
*/
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 ( pthread_cond_wait(&cond->cond, &mutex->id) != 0 ) {
SDL_SetError("pthread_cond_wait() failed");
retval = -1;
}
return retval;
}