Date: Fri, 25 Jun 2004 13:29:15 +0100

From: "alan buckley"
Subject: Modification for RISC OS version of SDL

Ive attached a zip file with the changes to this email, it contains the
following:

The file sdldiff.txt is the output from cvs diff u.  .
The directory thread/riscos contains all the new files to support threading.

Readme.riscos is a new readme file to add.

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%40956

src/thread/riscos/SDL_sysmutex.c

@@ -0,0 +1,160 @@
+/*
+    SDL - Simple DirectMedia Layer
+    Copyright (C) 1997-2004 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@libsdl.org
+*/
+
+/* RISC OS implementations uses pthreads based on linux code */
+
+#ifdef SAVE_RCSID
+static char rcsid =
+ "@(#) $Id$";
+#endif
+
+#ifdef DISABLE_THREADS
+#include "../generic/SDL_sysmutex.c"
+#else
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <pthread.h>
+
+#include "SDL_error.h"
+#include "SDL_thread.h"
+
+struct SDL_mutex {
+	pthread_mutex_t id;
+#ifdef PTHREAD_NO_RECURSIVE_MUTEX
+	int recursive;
+	pthread_t owner;
+#endif
+};
+
+SDL_mutex *SDL_CreateMutex (void)
+{
+	SDL_mutex *mutex;
+	pthread_mutexattr_t attr;
+
+	/* Allocate the structure */
+	mutex = (SDL_mutex *)calloc(1, sizeof(*mutex));
+	if ( mutex ) {
+		pthread_mutexattr_init(&attr);
+#ifdef PTHREAD_NO_RECURSIVE_MUTEX
+		/* No extra attributes necessary */
+#else
+		pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+#endif /* PTHREAD_NO_RECURSIVE_MUTEX */
+		if ( pthread_mutex_init(&mutex->id, &attr) != 0 ) {
+			SDL_SetError("pthread_mutex_init() failed");
+			free(mutex);
+			mutex = NULL;
+		}
+	} else {
+		SDL_OutOfMemory();
+	}
+	return(mutex);
+}
+
+void SDL_DestroyMutex(SDL_mutex *mutex)
+{
+	if ( mutex ) {
+		pthread_mutex_destroy(&mutex->id);
+		free(mutex);
+	}
+}
+
+/* Lock the mutex */
+int SDL_mutexP(SDL_mutex *mutex)
+{
+	int retval;
+#ifdef PTHREAD_NO_RECURSIVE_MUTEX
+	pthread_t this_thread;
+#endif
+
+	if ( mutex == NULL ) {
+		SDL_SetError("Passed a NULL mutex");
+		return -1;
+	}
+
+	retval = 0;
+#ifdef PTHREAD_NO_RECURSIVE_MUTEX
+	this_thread = pthread_self();
+	if ( mutex->owner == this_thread ) {
+		++mutex->recursive;
+	} else {
+		/* The order of operations is important.
+		   We set the locking thread id after we obtain the lock
+		   so unlocks from other threads will fail.
+		*/
+		if ( pthread_mutex_lock(&mutex->id) == 0 ) {
+			mutex->owner = this_thread;
+			mutex->recursive = 0;
+		} else {
+			SDL_SetError("pthread_mutex_lock() failed");
+			retval = -1;
+		}
+	}
+#else
+	if ( pthread_mutex_lock(&mutex->id) < 0 ) {
+		SDL_SetError("pthread_mutex_lock() failed");
+		retval = -1;
+	}
+#endif
+	return retval;
+}
+
+int SDL_mutexV(SDL_mutex *mutex)
+{
+	int retval;
+
+	if ( mutex == NULL ) {
+		SDL_SetError("Passed a NULL mutex");
+		return -1;
+	}
+
+	retval = 0;
+#ifdef PTHREAD_NO_RECURSIVE_MUTEX
+	/* We can only unlock the mutex if we own it */
+	if ( pthread_self() == mutex->owner ) {
+		if ( mutex->recursive ) {
+			--mutex->recursive;
+		} else {
+			/* The order of operations is important.
+			   First reset the owner so another thread doesn't lock
+			   the mutex and set the ownership before we reset it,
+			   then release the lock semaphore.
+			 */
+			mutex->owner = 0;
+			pthread_mutex_unlock(&mutex->id);
+		}
+	} else {
+		SDL_SetError("mutex not owned by this thread");
+		retval = -1;
+	}
+
+#else
+	if ( pthread_mutex_unlock(&mutex->id) < 0 ) {
+		SDL_SetError("pthread_mutex_unlock() failed");
+		retval = -1;
+	}
+#endif /* PTHREAD_NO_RECURSIVE_MUTEX */
+
+	return retval;
+}
+#endif