1 files changed, 318 insertions, 0 deletions
diff --git a/src/SDL2/include/SDL_atomic.h b/src/SDL2/include/SDL_atomic.h
new file mode 100644
index 00000000..4b737f54
--- /dev/null
+++ b/src/SDL2/include/SDL_atomic.h
@@ -0,0 +1,318 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2012 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.
+*/
+
+/**
+ * \file SDL_atomic.h
+ * 
+ * Atomic operations.
+ * 
+ * IMPORTANT:
+ * If you are not an expert in concurrent lockless programming, you should
+ * only be using the atomic lock and reference counting functions in this
+ * file.  In all other cases you should be protecting your data structures
+ * with full mutexes.
+ * 
+ * The list of "safe" functions to use are:
+ *  SDL_AtomicLock()
+ *  SDL_AtomicUnlock()
+ *  SDL_AtomicIncRef()
+ *  SDL_AtomicDecRef()
+ * 
+ * Seriously, here be dragons!
+ * ^^^^^^^^^^^^^^^^^^^^^^^^^^^
+ *
+ * You can find out a little more about lockless programming and the 
+ * subtle issues that can arise here:
+ * http://msdn.microsoft.com/en-us/library/ee418650%28v=vs.85%29.aspx
+ *
+ * There's also lots of good information here:
+ * http://www.1024cores.net/home/lock-free-algorithms
+ *
+ * These operations may or may not actually be implemented using
+ * processor specific atomic operations. When possible they are
+ * implemented as true processor specific atomic operations. When that
+ * is not possible the are implemented using locks that *do* use the
+ * available atomic operations.
+ *
+ * All of the atomic operations that modify memory are full memory barriers.
+ */
+
+#ifndef _SDL_atomic_h_
+#define _SDL_atomic_h_
+
+#include "SDL_stdinc.h"
+#include "SDL_platform.h"
+
+#include "begin_code.h"
+
+/* Need to do this here because intrin.h has C++ code in it */
+/* Visual Studio 2005 has a bug where intrin.h conflicts with winnt.h */
+#if defined(_MSC_VER) && (_MSC_VER >= 1500)
+#include <intrin.h>
+#define HAVE_MSC_ATOMICS 1
+#endif
+
+/* Set up for C function definitions, even when using C++ */
+#ifdef __cplusplus
+/* *INDENT-OFF* */
+extern "C" {
+/* *INDENT-ON* */
+#endif
+
+/**
+ * \name SDL AtomicLock
+ * 
+ * The atomic locks are efficient spinlocks using CPU instructions,
+ * but are vulnerable to starvation and can spin forever if a thread
+ * holding a lock has been terminated.  For this reason you should
+ * minimize the code executed inside an atomic lock and never do
+ * expensive things like API or system calls while holding them.
+ *
+ * The atomic locks are not safe to lock recursively.
+ *
+ * Porting Note:
+ * The spin lock functions and type are required and can not be
+ * emulated because they are used in the atomic emulation code.
+ */
+/*@{*/
+
+typedef int SDL_SpinLock;
+
+/**
+ * \brief Try to lock a spin lock by setting it to a non-zero value.
+ * 
+ * \param lock Points to the lock.
+ *
+ * \return SDL_TRUE if the lock succeeded, SDL_FALSE if the lock is already held.
+ */
+extern DECLSPEC SDL_bool SDLCALL SDL_AtomicTryLock(SDL_SpinLock *lock);
+
+/**
+ * \brief Lock a spin lock by setting it to a non-zero value.
+ * 
+ * \param lock Points to the lock.
+ */
+extern DECLSPEC void SDLCALL SDL_AtomicLock(SDL_SpinLock *lock);
+
+/**
+ * \brief Unlock a spin lock by setting it to 0. Always returns immediately
+ *
+ * \param lock Points to the lock.
+ */
+extern DECLSPEC void SDLCALL SDL_AtomicUnlock(SDL_SpinLock *lock);
+
+/*@}*//*SDL AtomicLock*/
+
+
+/**
+ * The compiler barrier prevents the compiler from reordering
+ * reads and writes to globally visible variables across the call.
+ */
+#ifdef _MSC_VER
+void _ReadWriteBarrier(void);
+#pragma intrinsic(_ReadWriteBarrier)
+#define SDL_CompilerBarrier()   _ReadWriteBarrier()
+#elif defined(__GNUC__)
+#define SDL_CompilerBarrier()   __asm__ __volatile__ ("" : : : "memory")
+#else
+#define SDL_CompilerBarrier()   \
+({ SDL_SpinLock _tmp = 0; SDL_AtomicLock(&_tmp); SDL_AtomicUnlock(&_tmp); })
+#endif
+
+/* Platform specific optimized versions of the atomic functions,
+ * you can disable these by defining SDL_DISABLE_ATOMIC_INLINE
+ */
+#if defined(SDL_ATOMIC_DISABLED) && SDL_ATOMIC_DISABLED
+#define SDL_DISABLE_ATOMIC_INLINE
+#endif
+#ifndef SDL_DISABLE_ATOMIC_INLINE
+
+#ifdef HAVE_MSC_ATOMICS
+
+#define SDL_AtomicSet(a, v)     _InterlockedExchange((long*)&(a)->value, (v))
+#define SDL_AtomicAdd(a, v)     _InterlockedExchangeAdd((long*)&(a)->value, (v))
+#define SDL_AtomicCAS(a, oldval, newval) (_InterlockedCompareExchange((long*)&(a)->value, (newval), (oldval)) == (oldval))
+#define SDL_AtomicSetPtr(a, v)  _InterlockedExchangePointer((a), (v))
+#if _M_IX86
+#define SDL_AtomicCASPtr(a, oldval, newval) (_InterlockedCompareExchange((long*)(a), (long)(newval), (long)(oldval)) == (long)(oldval))
+#else
+#define SDL_AtomicCASPtr(a, oldval, newval) (_InterlockedCompareExchangePointer((a), (newval), (oldval)) == (oldval))
+#endif
+
+#elif defined(__MACOSX__)
+#include <libkern/OSAtomic.h>
+
+#define SDL_AtomicCAS(a, oldval, newval) OSAtomicCompareAndSwap32Barrier((oldval), (newval), &(a)->value)
+#ifdef __LP64__
+#define SDL_AtomicCASPtr(a, oldval, newval) OSAtomicCompareAndSwap64Barrier((int64_t)(oldval), (int64_t)(newval), (int64_t*)(a))
+#else
+#define SDL_AtomicCASPtr(a, oldval, newval) OSAtomicCompareAndSwap32Barrier((int32_t)(oldval), (int32_t)(newval), (int32_t*)(a))
+#endif
+
+#elif defined(HAVE_GCC_ATOMICS)
+
+#define SDL_AtomicSet(a, v)     __sync_lock_test_and_set(&(a)->value, v)
+#define SDL_AtomicAdd(a, v)     __sync_fetch_and_add(&(a)->value, v)
+#define SDL_AtomicSetPtr(a, v)  __sync_lock_test_and_set(a, v)
+#define SDL_AtomicCAS(a, oldval, newval) __sync_bool_compare_and_swap(&(a)->value, oldval, newval)
+#define SDL_AtomicCASPtr(a, oldval, newval) __sync_bool_compare_and_swap(a, oldval, newval)
+
+#endif
+
+#endif /* !SDL_DISABLE_ATOMIC_INLINE */
+
+
+/**
+ * \brief A type representing an atomic integer value.  It is a struct
+ *        so people don't accidentally use numeric operations on it.
+ */
+#ifndef SDL_atomic_t_defined
+typedef struct { int value; } SDL_atomic_t;
+#endif
+
+/**
+ * \brief Set an atomic variable to a new value if it is currently an old value.
+ *
+ * \return SDL_TRUE if the atomic variable was set, SDL_FALSE otherwise.
+ *
+ * \note If you don't know what this function is for, you shouldn't use it!
+*/
+#ifndef SDL_AtomicCAS
+#define SDL_AtomicCAS SDL_AtomicCAS_
+#endif
+extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCAS_(SDL_atomic_t *a, int oldval, int newval);
+
+/**
+ * \brief Set an atomic variable to a value.
+ *
+ * \return The previous value of the atomic variable.
+ */
+#ifndef SDL_AtomicSet
+static __inline__ int SDL_AtomicSet(SDL_atomic_t *a, int v)
+{
+    int value;
+    do {
+        value = a->value;
+    } while (!SDL_AtomicCAS(a, value, v));
+    return value;
+}
+#endif
+
+/**
+ * \brief Get the value of an atomic variable
+ */
+#ifndef SDL_AtomicGet
+static __inline__ int SDL_AtomicGet(SDL_atomic_t *a)
+{
+    int value = a->value;
+    SDL_CompilerBarrier();
+    return value;
+}
+#endif
+
+/**
+ * \brief Add to an atomic variable.
+ *
+ * \return The previous value of the atomic variable.
+ *
+ * \note This same style can be used for any number operation
+ */
+#ifndef SDL_AtomicAdd
+static __inline__ int SDL_AtomicAdd(SDL_atomic_t *a, int v)
+{
+    int value;
+    do {
+        value = a->value;
+    } while (!SDL_AtomicCAS(a, value, (value + v)));
+    return value;
+}
+#endif
+
+/**
+ * \brief Increment an atomic variable used as a reference count.
+ */
+#ifndef SDL_AtomicIncRef
+#define SDL_AtomicIncRef(a)    SDL_AtomicAdd(a, 1)
+#endif
+
+/**
+ * \brief Decrement an atomic variable used as a reference count.
+ *
+ * \return SDL_TRUE if the variable reached zero after decrementing,
+ *         SDL_FALSE otherwise
+ */
+#ifndef SDL_AtomicDecRef
+#define SDL_AtomicDecRef(a)    (SDL_AtomicAdd(a, -1) == 1)
+#endif
+
+/**
+ * \brief Set a pointer to a new value if it is currently an old value.
+ *
+ * \return SDL_TRUE if the pointer was set, SDL_FALSE otherwise.
+ *
+ * \note If you don't know what this function is for, you shouldn't use it!
+*/
+#ifndef SDL_AtomicCASPtr
+#define SDL_AtomicCASPtr SDL_AtomicCASPtr_
+#endif
+extern DECLSPEC SDL_bool SDLCALL SDL_AtomicCASPtr_(void* *a, void *oldval, void *newval);
+
+/**
+ * \brief Set a pointer to a value atomically.
+ *
+ * \return The previous value of the pointer.
+ */
+#ifndef SDL_AtomicSetPtr
+static __inline__ void* SDL_AtomicSetPtr(void* *a, void* v)
+{
+    void* value;
+    do {
+        value = *a;
+    } while (!SDL_AtomicCASPtr(a, value, v));
+    return value;
+}
+#endif
+
+/**
+ * \brief Get the value of a pointer atomically.
+ */
+#ifndef SDL_AtomicGetPtr
+static __inline__ void* SDL_AtomicGetPtr(void* *a)
+{
+    void* value = *a;
+    SDL_CompilerBarrier();
+    return value;
+}
+#endif
+
+
+/* Ends C function definitions when using C++ */
+#ifdef __cplusplus
+/* *INDENT-OFF* */
+}
+/* *INDENT-ON* */
+#endif
+
+#include "close_code.h"
+
+#endif /* _SDL_atomic_h_ */
+
+/* vi: set ts=4 sw=4 expandtab: */