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engines/hpl1/engine/libraries/angelscript/sources/as_criticalsection.h

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+/*
+   AngelCode Scripting Library
+   Copyright (c) 2003-2017 Andreas Jonsson
+
+   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.
+
+   The original version of this library can be located at:
+   http://www.angelcode.com/angelscript/
+
+   Andreas Jonsson
+   andreas@angelcode.com
+*/
+
+
+
+//
+// as_criticalsection.h
+//
+// Classes for multi threading support
+//
+
+#ifndef AS_CRITICALSECTION_H
+#define AS_CRITICALSECTION_H
+
+#include "as_config.h"
+
+BEGIN_AS_NAMESPACE
+
+#ifdef AS_NO_THREADS
+
+#define DECLARECRITICALSECTION(x)
+#define ENTERCRITICALSECTION(x)
+#define LEAVECRITICALSECTION(x)
+
+inline bool tryEnter() {
+	return true;
+}
+#define TRYENTERCRITICALSECTION(x) tryEnter()
+
+#define DECLAREREADWRITELOCK(x)
+#define ACQUIREEXCLUSIVE(x)
+#define RELEASEEXCLUSIVE(x)
+#define ACQUIRESHARED(x)
+#define RELEASESHARED(x)
+
+#else
+
+#define DECLARECRITICALSECTION(x)  asCThreadCriticalSection x;
+#define ENTERCRITICALSECTION(x)    x.Enter()
+#define LEAVECRITICALSECTION(x)    x.Leave()
+#define TRYENTERCRITICALSECTION(x) x.TryEnter()
+
+#define DECLAREREADWRITELOCK(x)    asCThreadReadWriteLock x;
+#define ACQUIREEXCLUSIVE(x)        x.AcquireExclusive()
+#define RELEASEEXCLUSIVE(x)        x.ReleaseExclusive()
+#define ACQUIRESHARED(x)           x.AcquireShared()
+#define RELEASESHARED(x)           x.ReleaseShared()
+
+#ifdef AS_POSIX_THREADS
+
+END_AS_NAMESPACE
+#include <pthread.h>
+BEGIN_AS_NAMESPACE
+
+class asCThreadCriticalSection {
+public:
+	asCThreadCriticalSection();
+	~asCThreadCriticalSection();
+
+	void Enter();
+	void Leave();
+	bool TryEnter();
+
+protected:
+	pthread_mutex_t cs;
+};
+
+class asCThreadReadWriteLock {
+public:
+	asCThreadReadWriteLock();
+	~asCThreadReadWriteLock();
+
+	void AcquireExclusive();
+	void ReleaseExclusive();
+	bool TryAcquireExclusive();
+
+	void AcquireShared();
+	void ReleaseShared();
+	bool TryAcquireShared();
+
+protected:
+	pthread_rwlock_t lock;
+};
+
+#elif defined(AS_WINDOWS_THREADS)
+
+END_AS_NAMESPACE
+#ifdef AS_XBOX360
+#include <xtl.h>
+#else
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#ifndef _WIN32_WINNT
+#define _WIN32_WINNT 0x0600 // We need this to get the declaration for Windows Phone compatible Ex functions
+#endif
+#include <windows.h>
+#endif
+BEGIN_AS_NAMESPACE
+
+// Undefine macros that cause problems in our code
+#undef GetObject
+#undef RegisterClass
+
+class asCThreadCriticalSection {
+public:
+	asCThreadCriticalSection();
+	~asCThreadCriticalSection();
+
+	void Enter();
+	void Leave();
+	bool TryEnter();
+
+protected:
+	CRITICAL_SECTION cs;
+};
+
+class asCThreadReadWriteLock {
+public:
+	asCThreadReadWriteLock();
+	~asCThreadReadWriteLock();
+
+	void AcquireExclusive();
+	void ReleaseExclusive();
+
+	void AcquireShared();
+	void ReleaseShared();
+
+protected:
+	// The Slim Read Write Lock object, SRWLOCK, is more efficient
+	// but it is only available from Windows Vista so we cannot use it and
+	// maintain compatibility with olders versions of Windows.
+
+	// Critical sections and semaphores are available on Windows XP and onwards.
+	// Windows XP is oldest version we support with multithreading.
+
+	// The implementation is based on the following article, that shows
+	// how to implement a fair read/write lock that doesn't risk starving
+	// the writers:
+
+	// http://doc.qt.nokia.com/qq/qq11-mutex.html
+
+	// TODO: Allow use of SRWLOCK through configuration in as_config.h
+
+	CRITICAL_SECTION    writeLock;
+	HANDLE              readLocks;
+};
+
+// This constant really should be a member of asCThreadReadWriteLock,
+// but it gives a compiler error on MSVC6 so I'm leaving it outside
+static const asUINT maxReaders = 10;
+
+#endif
+
+#endif
+
+END_AS_NAMESPACE
+
+#endif
+