early-access version 1611

externals/SDL/src/thread/windows/SDL_sysmutex.c

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+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "../../SDL_internal.h"
+
+#if SDL_THREAD_WINDOWS
+
+/* Mutex functions using the Win32 API */
+
+#include "../../core/windows/SDL_windows.h"
+
+#include "SDL_mutex.h"
+
+
+struct SDL_mutex
+{
+    CRITICAL_SECTION cs;
+};
+
+/* Create a mutex */
+SDL_mutex *
+SDL_CreateMutex(void)
+{
+    SDL_mutex *mutex;
+
+    /* Allocate mutex memory */
+    mutex = (SDL_mutex *) SDL_malloc(sizeof(*mutex));
+    if (mutex) {
+        /* Initialize */
+        /* On SMP systems, a non-zero spin count generally helps performance */
+#if __WINRT__
+        InitializeCriticalSectionEx(&mutex->cs, 2000, 0);
+#else
+        InitializeCriticalSectionAndSpinCount(&mutex->cs, 2000);
+#endif
+    } else {
+        SDL_OutOfMemory();
+    }
+    return (mutex);
+}
+
+/* Free the mutex */
+void
+SDL_DestroyMutex(SDL_mutex * mutex)
+{
+    if (mutex) {
+        DeleteCriticalSection(&mutex->cs);
+        SDL_free(mutex);
+    }
+}
+
+/* Lock the mutex */
+int
+SDL_LockMutex(SDL_mutex * mutex)
+{
+    if (mutex == NULL) {
+        return SDL_SetError("Passed a NULL mutex");
+    }
+
+    EnterCriticalSection(&mutex->cs);
+    return (0);
+}
+
+/* TryLock the mutex */
+int
+SDL_TryLockMutex(SDL_mutex * mutex)
+{
+    int retval = 0;
+    if (mutex == NULL) {
+        return SDL_SetError("Passed a NULL mutex");
+    }
+
+    if (TryEnterCriticalSection(&mutex->cs) == 0) {
+        retval = SDL_MUTEX_TIMEDOUT;
+    }
+    return retval;
+}
+
+/* Unlock the mutex */
+int
+SDL_UnlockMutex(SDL_mutex * mutex)
+{
+    if (mutex == NULL) {
+        return SDL_SetError("Passed a NULL mutex");
+    }
+
+    LeaveCriticalSection(&mutex->cs);
+    return (0);
+}
+
+#endif /* SDL_THREAD_WINDOWS */
+
+/* vi: set ts=4 sw=4 expandtab: */