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Diffstat (limited to 'distrib/sdl-1.2.15/src/thread/dc/SDL_sysmutex.c')
-rw-r--r--distrib/sdl-1.2.15/src/thread/dc/SDL_sysmutex.c122
1 files changed, 122 insertions, 0 deletions
diff --git a/distrib/sdl-1.2.15/src/thread/dc/SDL_sysmutex.c b/distrib/sdl-1.2.15/src/thread/dc/SDL_sysmutex.c
new file mode 100644
index 0000000..c6c4651
--- /dev/null
+++ b/distrib/sdl-1.2.15/src/thread/dc/SDL_sysmutex.c
@@ -0,0 +1,122 @@
+/*
+ SDL - Simple DirectMedia Layer
+ Copyright (C) 1997-2012 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"
+
+/* An implementation of mutexes using semaphores */
+
+#include "SDL_thread.h"
+#include "SDL_systhread_c.h"
+
+#include <arch/spinlock.h>
+
+struct SDL_mutex {
+ int recursive;
+ Uint32 owner;
+ spinlock_t mutex;
+};
+
+/* Create a mutex */
+SDL_mutex *SDL_CreateMutex(void)
+{
+ SDL_mutex *mutex;
+
+ /* Allocate mutex memory */
+ mutex = (SDL_mutex *)SDL_malloc(sizeof(*mutex));
+ if ( mutex ) {
+ spinlock_init(&mutex->mutex);
+ mutex->recursive = 0;
+ mutex->owner = 0;
+ } else {
+ SDL_OutOfMemory();
+ }
+ return mutex;
+}
+
+/* Free the mutex */
+void SDL_DestroyMutex(SDL_mutex *mutex)
+{
+ if ( mutex ) {
+ SDL_free(mutex);
+ }
+}
+
+/* Lock the semaphore */
+int SDL_mutexP(SDL_mutex *mutex)
+{
+#if SDL_THREADS_DISABLED
+ return SDL_arraysize(return ),0;
+#else
+ Uint32 this_thread;
+
+ if ( mutex == NULL ) {
+ SDL_SetError("Passed a NULL mutex");
+ return -1;
+ }
+
+ this_thread = SDL_ThreadID();
+ 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.
+ */
+ spinlock_lock(&mutex->mutex);
+ mutex->owner = this_thread;
+ mutex->recursive = 0;
+ }
+
+ return 0;
+#endif /* SDL_THREADS_DISABLED */
+}
+
+/* Unlock the mutex */
+int SDL_mutexV(SDL_mutex *mutex)
+{
+#if SDL_THREADS_DISABLED
+ return 0;
+#else
+ if ( mutex == NULL ) {
+ SDL_SetError("Passed a NULL mutex");
+ return -1;
+ }
+
+ /* If we don't own the mutex, we can't unlock it */
+ if ( SDL_ThreadID() != mutex->owner ) {
+ SDL_SetError("mutex not owned by this thread");
+ return -1;
+ }
+
+ 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;
+ spinlock_unlock(&mutex->mutex);
+ }
+ return 0;
+#endif /* SDL_THREADS_DISABLED */
+}