view src/thread/SDL_thread.c @ 4179:d7294b7c732d SDL-1.2

Date: Fri, 24 Apr 2009 17:47:07 +0200 From: Stefan Klug Subject: Re: [SDL] SVN doesn't compile for wince the patch applied for Revision 4483 was seemingly not checked for side effects. It broke the WinCE build. The attached patch should fix these problems. I'm not using SDL 1.2 on CE anymore, and therefore haven't tested the patch... but at least it compiles ;-) Regards Stefan
author Sam Lantinga <slouken@libsdl.org>
date Thu, 07 May 2009 12:40:16 +0000
parents a1b03ba2fcd0
children 88aa213ffc7b
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/*
    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"

/* System independent thread management routines for SDL */

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

#define ARRAY_CHUNKSIZE	32
/* The array of threads currently active in the application
   (except the main thread)
   The manipulation of an array here is safer than using a linked list.
*/
static int SDL_maxthreads = 0;
static int SDL_numthreads = 0;
static SDL_Thread **SDL_Threads = NULL;
static SDL_mutex *thread_lock = NULL;

int SDL_ThreadsInit(void)
{
	int retval;

	retval = 0;
	thread_lock = SDL_CreateMutex();
	if ( thread_lock == NULL ) {
		retval = -1;
	}
	return(retval);
}

/* This should never be called...
   If this is called by SDL_Quit(), we don't know whether or not we should
   clean up threads here.  If any threads are still running after this call,
   they will no longer have access to any per-thread data.
 */
void SDL_ThreadsQuit(void)
{
	SDL_mutex *mutex;

	mutex = thread_lock;
	thread_lock = NULL;
	if ( mutex != NULL ) {
		SDL_DestroyMutex(mutex);
	}
}

/* Routines for manipulating the thread list */
static void SDL_AddThread(SDL_Thread *thread)
{
	/* WARNING:
	   If the very first threads are created simultaneously, then
	   there could be a race condition causing memory corruption.
	   In practice, this isn't a problem because by definition there
	   is only one thread running the first time this is called.
	*/
	if ( !thread_lock ) {
		if ( SDL_ThreadsInit() < 0 ) {
			return;
		}
	}
	SDL_mutexP(thread_lock);

	/* Expand the list of threads, if necessary */
#ifdef DEBUG_THREADS
	printf("Adding thread (%d already - %d max)\n",
			SDL_numthreads, SDL_maxthreads);
#endif
	if ( SDL_numthreads == SDL_maxthreads ) {
		SDL_Thread **threads;
		threads = (SDL_Thread **)SDL_realloc(SDL_Threads,
			(SDL_maxthreads+ARRAY_CHUNKSIZE)*(sizeof *threads));
		if ( threads == NULL ) {
			SDL_OutOfMemory();
			goto done;
		}
		SDL_maxthreads += ARRAY_CHUNKSIZE;
		SDL_Threads = threads;
	}
	SDL_Threads[SDL_numthreads++] = thread;
done:
	SDL_mutexV(thread_lock);
}

static void SDL_DelThread(SDL_Thread *thread)
{
	int i;

	if ( !thread_lock ) {
		return;
	}
	SDL_mutexP(thread_lock);
	for ( i=0; i<SDL_numthreads; ++i ) {
		if ( thread == SDL_Threads[i] ) {
			break;
		}
	}
	if ( i < SDL_numthreads ) {
		if ( --SDL_numthreads > 0 ) {
			while ( i < SDL_numthreads ) {
				SDL_Threads[i] = SDL_Threads[i+1];
				++i;
			}
		} else {
			SDL_maxthreads = 0;
			SDL_free(SDL_Threads);
			SDL_Threads = NULL;
		}
#ifdef DEBUG_THREADS
		printf("Deleting thread (%d left - %d max)\n",
				SDL_numthreads, SDL_maxthreads);
#endif
	}
	SDL_mutexV(thread_lock);

	if ( SDL_Threads == NULL ) {
		SDL_ThreadsQuit();
	}
}

/* The default (non-thread-safe) global error variable */
static SDL_error SDL_global_error;

/* Routine to get the thread-specific error variable */
SDL_error *SDL_GetErrBuf(void)
{
	SDL_error *errbuf;

	errbuf = &SDL_global_error;
	if ( SDL_Threads ) {
		int i;
		Uint32 this_thread;

		this_thread = SDL_ThreadID();
		SDL_mutexP(thread_lock);
		for ( i=0; i<SDL_numthreads; ++i ) {
			if ( this_thread == SDL_Threads[i]->threadid ) {
				errbuf = &SDL_Threads[i]->errbuf;
				break;
			}
		}
		SDL_mutexV(thread_lock);
	}
	return(errbuf);
}


/* Arguments and callback to setup and run the user thread function */
typedef struct {
	int (SDLCALL *func)(void *);
	void *data;
	SDL_Thread *info;
	SDL_sem *wait;
} thread_args;

void SDL_RunThread(void *data)
{
	thread_args *args;
	int (SDLCALL *userfunc)(void *);
	void *userdata;
	int *statusloc;

	/* Perform any system-dependent setup
	   - this function cannot fail, and cannot use SDL_SetError()
	 */
	SDL_SYS_SetupThread();

	/* Get the thread id */
	args = (thread_args *)data;
	args->info->threadid = SDL_ThreadID();

	/* Figure out what function to run */
	userfunc = args->func;
	userdata = args->data;
	statusloc = &args->info->status;

	/* Wake up the parent thread */
	SDL_SemPost(args->wait);

	/* Run the function */
	*statusloc = userfunc(userdata);
}

#ifdef SDL_PASSED_BEGINTHREAD_ENDTHREAD
#undef SDL_CreateThread
DECLSPEC SDL_Thread * SDLCALL SDL_CreateThread(int (SDLCALL *fn)(void *), void *data, pfnSDL_CurrentBeginThread pfnBeginThread, pfnSDL_CurrentEndThread pfnEndThread)
#else
DECLSPEC SDL_Thread * SDLCALL SDL_CreateThread(int (SDLCALL *fn)(void *), void *data)
#endif
{
	SDL_Thread *thread;
	thread_args *args;
	int ret;

	/* Allocate memory for the thread info structure */
	thread = (SDL_Thread *)SDL_malloc(sizeof(*thread));
	if ( thread == NULL ) {
		SDL_OutOfMemory();
		return(NULL);
	}
	SDL_memset(thread, 0, (sizeof *thread));
	thread->status = -1;

	/* Set up the arguments for the thread */
	args = (thread_args *)SDL_malloc(sizeof(*args));
	if ( args == NULL ) {
		SDL_OutOfMemory();
		SDL_free(thread);
		return(NULL);
	}
	args->func = fn;
	args->data = data;
	args->info = thread;
	args->wait = SDL_CreateSemaphore(0);
	if ( args->wait == NULL ) {
		SDL_free(thread);
		SDL_free(args);
		return(NULL);
	}

	/* Add the thread to the list of available threads */
	SDL_AddThread(thread);

	/* Create the thread and go! */
#ifdef SDL_PASSED_BEGINTHREAD_ENDTHREAD
	ret = SDL_SYS_CreateThread(thread, args, pfnBeginThread, pfnEndThread);
#else
	ret = SDL_SYS_CreateThread(thread, args);
#endif
	if ( ret >= 0 ) {
		/* Wait for the thread function to use arguments */
		SDL_SemWait(args->wait);
	} else {
		/* Oops, failed.  Gotta free everything */
		SDL_DelThread(thread);
		SDL_free(thread);
		thread = NULL;
	}
	SDL_DestroySemaphore(args->wait);
	SDL_free(args);

	/* Everything is running now */
	return(thread);
}

void SDL_WaitThread(SDL_Thread *thread, int *status)
{
	if ( thread ) {
		SDL_SYS_WaitThread(thread);
		if ( status ) {
			*status = thread->status;
		}
		SDL_DelThread(thread);
		SDL_free(thread);
	}
}

Uint32 SDL_GetThreadID(SDL_Thread *thread)
{
	Uint32 id;

	if ( thread ) {
		id = thread->threadid;
	} else {
		id = SDL_ThreadID();
	}
	return(id);
}

void SDL_KillThread(SDL_Thread *thread)
{
	if ( thread ) {
		SDL_SYS_KillThread(thread);
		SDL_WaitThread(thread, NULL);
	}
}