view src/thread/pthread/SDL_systhread.c @ 3880:74e828c64315 SDL-1.2

Fixed bug #292 I might be on crack here. It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and right channels of a stereo stream together, and clamps the new mono channel if it would overflow. Shouldn't it be dividing by 2 to average the two sample points instead of clamping? Otherwise the mono sample point's volume doubles in the conversion. This would also make the conversion faster, as it replaces two branches per sample frame with a bitwise shift. --ryan.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 24 Sep 2006 15:45:37 +0000
parents 1e8582152d44
children 782fd950bd46 c121d94672cb a1b03ba2fcd0
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/*
    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"

#include <pthread.h>
#include <signal.h>

#include "SDL_thread.h"
#include "../SDL_thread_c.h"
#include "../SDL_systhread.h"

/* List of signals to mask in the subthreads */
static int sig_list[] = {
	SIGHUP, SIGINT, SIGQUIT, SIGPIPE, SIGALRM, SIGTERM, SIGCHLD, SIGWINCH,
	SIGVTALRM, SIGPROF, 0
};

#ifdef __RISCOS__
/* RISC OS needs to know the main thread for
 * it's timer and event processing. */
int riscos_using_threads = 0;
Uint32 riscos_main_thread = 0; /* Thread running events */
#endif
 

static void *RunThread(void *data)
{
	SDL_RunThread(data);
	pthread_exit((void*)0);
	return((void *)0);		/* Prevent compiler warning */
}

int SDL_SYS_CreateThread(SDL_Thread *thread, void *args)
{
	pthread_attr_t type;

	/* Set the thread attributes */
	if ( pthread_attr_init(&type) != 0 ) {
		SDL_SetError("Couldn't initialize pthread attributes");
		return(-1);
	}
	pthread_attr_setdetachstate(&type, PTHREAD_CREATE_JOINABLE);

	/* Create the thread and go! */
	if ( pthread_create(&thread->handle, &type, RunThread, args) != 0 ) {
		SDL_SetError("Not enough resources to create thread");
		return(-1);
	}

#ifdef __RISCOS__
	if (riscos_using_threads == 0) {
		riscos_using_threads = 1;
		riscos_main_thread = SDL_ThreadID();
	}
#endif

	return(0);
}

void SDL_SYS_SetupThread(void)
{
	int i;
	sigset_t mask;

	/* Mask asynchronous signals for this thread */
	sigemptyset(&mask);
	for ( i=0; sig_list[i]; ++i ) {
		sigaddset(&mask, sig_list[i]);
	}
	pthread_sigmask(SIG_BLOCK, &mask, 0);

#ifdef PTHREAD_CANCEL_ASYNCHRONOUS
	/* Allow ourselves to be asynchronously cancelled */
	{ int oldstate;
		pthread_setcanceltype(PTHREAD_CANCEL_ASYNCHRONOUS, &oldstate);
	}
#endif
}

/* WARNING:  This may not work for systems with 64-bit pid_t */
Uint32 SDL_ThreadID(void)
{
	return((Uint32)pthread_self());
}

void SDL_SYS_WaitThread(SDL_Thread *thread)
{
	pthread_join(thread->handle, 0);
}

void SDL_SYS_KillThread(SDL_Thread *thread)
{
#ifdef PTHREAD_CANCEL_ASYNCHRONOUS
	pthread_cancel(thread->handle);
#else
#ifdef __FREEBSD__
#warning For some reason, this doesnt actually kill a thread - FreeBSD 3.2
#endif
	pthread_kill(thread->handle, SIGKILL);
#endif
}