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authorJesse Hall <jessehall@google.com>2012-07-23 10:12:30 -0700
committerandroid code review <noreply-gerritcodereview@google.com>2012-07-23 10:12:30 -0700
commit2b3a42e7d0b441f71fc2e2b07269dd1f8151c977 (patch)
treeded6ee18c4e1f33df235e53615a6d65e2d64f4ef /distrib/sdl-1.2.15/src/thread/generic/SDL_sysmutex.c
parent3dcbebfd43e409c3bbff7fc79288e40666a947fd (diff)
parent9682c8870b8ff5e4ac2e4c70b759f791c6f38c1f (diff)
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Merge changes I505c4aea,I2ae0529c
* changes: Import SDL release-1.2.15 Handle SDL windows with BGRA color
Diffstat (limited to 'distrib/sdl-1.2.15/src/thread/generic/SDL_sysmutex.c')
-rw-r--r--distrib/sdl-1.2.15/src/thread/generic/SDL_sysmutex.c129
1 files changed, 129 insertions, 0 deletions
diff --git a/distrib/sdl-1.2.15/src/thread/generic/SDL_sysmutex.c b/distrib/sdl-1.2.15/src/thread/generic/SDL_sysmutex.c
new file mode 100644
index 0000000..ecfea87
--- /dev/null
+++ b/distrib/sdl-1.2.15/src/thread/generic/SDL_sysmutex.c
@@ -0,0 +1,129 @@
+/*
+ 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"
+
+
+struct SDL_mutex {
+ int recursive;
+ Uint32 owner;
+ SDL_sem *sem;
+};
+
+/* Create a mutex */
+SDL_mutex *SDL_CreateMutex(void)
+{
+ SDL_mutex *mutex;
+
+ /* Allocate mutex memory */
+ mutex = (SDL_mutex *)SDL_malloc(sizeof(*mutex));
+ if ( mutex ) {
+ /* Create the mutex semaphore, with initial value 1 */
+ mutex->sem = SDL_CreateSemaphore(1);
+ mutex->recursive = 0;
+ mutex->owner = 0;
+ if ( ! mutex->sem ) {
+ SDL_free(mutex);
+ mutex = NULL;
+ }
+ } else {
+ SDL_OutOfMemory();
+ }
+ return mutex;
+}
+
+/* Free the mutex */
+void SDL_DestroyMutex(SDL_mutex *mutex)
+{
+ if ( mutex ) {
+ if ( mutex->sem ) {
+ SDL_DestroySemaphore(mutex->sem);
+ }
+ SDL_free(mutex);
+ }
+}
+
+/* Lock the semaphore */
+int SDL_mutexP(SDL_mutex *mutex)
+{
+#if SDL_THREADS_DISABLED
+ 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.
+ */
+ SDL_SemWait(mutex->sem);
+ 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;
+ SDL_SemPost(mutex->sem);
+ }
+ return 0;
+#endif /* SDL_THREADS_DISABLED */
+}