src/thread/SDL_thread.c
changeset 0 74212992fb08
child 252 e8157fcb3114
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/thread/SDL_thread.c	Thu Apr 26 16:45:43 2001 +0000
@@ -0,0 +1,300 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997, 1998, 1999, 2000, 2001  Sam Lantinga
+
+    This library is free software; you can redistribute it and/or
+    modify it under the terms of the GNU Library General Public
+    License as published by the Free Software Foundation; either
+    version 2 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
+    Library General Public License for more details.
+
+    You should have received a copy of the GNU Library General Public
+    License along with this library; if not, write to the Free
+    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+    Sam Lantinga
+    slouken@devolution.com
+*/
+
+#ifdef SAVE_RCSID
+static char rcsid =
+ "@(#) $Id$";
+#endif
+
+/* System independent thread management routines for SDL */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "SDL_error.h"
+#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 _creating_thread_lock = 0;
+
+int SDL_ThreadsInit(void)
+{
+	int retval;
+
+	retval = 0;
+	/* Set the thread lock creation flag so that we can reuse an
+	   existing lock on the system - since this mutex never gets
+	   destroyed (see SDL_ThreadsQuit()), we want to reuse it.
+	*/
+	_creating_thread_lock = 1;
+	thread_lock = SDL_CreateMutex();
+	_creating_thread_lock = 0;
+	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()
+{
+	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)
+{
+	SDL_Thread **threads;
+
+	/* 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 == NULL ) {
+		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 ) {
+		threads=(SDL_Thread **)malloc((SDL_maxthreads+ARRAY_CHUNKSIZE)*
+		                              (sizeof *threads));
+		if ( threads == NULL ) {
+			SDL_OutOfMemory();
+			goto done;
+		}
+		memcpy(threads, SDL_Threads, SDL_numthreads*(sizeof *threads));
+		SDL_maxthreads += ARRAY_CHUNKSIZE;
+		if ( SDL_Threads ) {
+			free(SDL_Threads);
+		}
+		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 ) {
+		SDL_mutexP(thread_lock);
+		for ( i=0; i<SDL_numthreads; ++i ) {
+			if ( thread == SDL_Threads[i] ) {
+				break;
+			}
+		}
+		if ( i < SDL_numthreads ) {
+			--SDL_numthreads;
+			while ( i < SDL_numthreads ) {
+				SDL_Threads[i] = SDL_Threads[i+1];
+				++i;
+			}
+#ifdef DEBUG_THREADS
+			printf("Deleting thread (%d left - %d max)\n",
+					SDL_numthreads, SDL_maxthreads);
+#endif
+		}
+		SDL_mutexV(thread_lock);
+	}
+}
+
+/* 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 (*func)(void *);
+	void *data;
+	SDL_Thread *info;
+	SDL_sem *wait;
+} thread_args;
+
+void SDL_RunThread(void *data)
+{
+	thread_args *args;
+	int (*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);
+}
+
+SDL_Thread *SDL_CreateThread(int (*fn)(void *), void *data)
+{
+	SDL_Thread *thread;
+	thread_args *args;
+	int ret;
+
+	/* Allocate memory for the thread info structure */
+	thread = (SDL_Thread *)malloc(sizeof(*thread));
+	if ( thread == NULL ) {
+		SDL_OutOfMemory();
+		return(NULL);
+	}
+	memset(thread, 0, (sizeof *thread));
+	thread->status = -1;
+
+	/* Set up the arguments for the thread */
+	args = (thread_args *)malloc(sizeof(*args));
+	if ( args == NULL ) {
+		SDL_OutOfMemory();
+		free(thread);
+		return(NULL);
+	}
+	args->func = fn;
+	args->data = data;
+	args->info = thread;
+	args->wait = SDL_CreateSemaphore(0);
+	if ( args->wait == NULL ) {
+		free(thread);
+		free(args);
+		return(NULL);
+	}
+
+	/* Add the thread to the list of available threads */
+	SDL_AddThread(thread);
+
+	/* Create the thread and go! */
+	ret = SDL_SYS_CreateThread(thread, args);
+	if ( ret >= 0 ) {
+		/* Wait for the thread function to use arguments */
+		SDL_SemWait(args->wait);
+	} else {
+		/* Oops, failed.  Gotta free everything */
+		SDL_DelThread(thread);
+		free(thread);
+		thread = NULL;
+	}
+	SDL_DestroySemaphore(args->wait);
+	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);
+		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);
+	}
+}
+