/*

Stockfish, a UCI chess playing engine derived from Glaurung 2.1

Copyright (C) 2004-2008 Tord Romstad (Glaurung author)

Copyright (C) 2008-2015 Marco Costalba, Joona Kiiski, Tord Romstad

Copyright (C) 2015-2019 Marco Costalba, Joona Kiiski, Gary Linscott, Tord Romstad

Stockfish is free software: you can redistribute it and/or modify

it under the terms of the GNU General Public License as published by

the Free Software Foundation, either version 3 of the License, or

(at your option) any later version.

Stockfish 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 General Public License for more details.

You should have received a copy of the GNU General Public License

along with this program. If not, see <http://www.gnu.org/licenses/>.

*/

#ifndef THREAD_WIN32_H_INCLUDED

#define THREAD_WIN32_H_INCLUDED

/// STL thread library used by mingw and gcc when cross compiling for Windows

/// relies on libwinpthread. Currently libwinpthread implements mutexes directly

/// on top of Windows semaphores. Semaphores, being kernel objects, require kernel

/// mode transition in order to lock or unlock, which is very slow compared to

/// interlocked operations (about 30% slower on bench test). To work around this

/// issue, we define our wrappers to the low level Win32 calls. We use critical

/// sections to support Windows XP and older versions. Unfortunately, cond_wait()

/// is racy between unlock() and WaitForSingleObject() but they have the same

/// speed performance as the SRW locks.

#include <condition_variable>

#include <mutex>

#if defined(_WIN32) && !defined(_MSC_VER)

#ifndef NOMINMAX

# define NOMINMAX // Disable macros min() and max()

#endif

#define WIN32_LEAN_AND_MEAN

#include <windows.h>

#undef WIN32_LEAN_AND_MEAN

#undef NOMINMAX

/// Mutex and ConditionVariable struct are wrappers of the low level locking

/// machinery and are modeled after the corresponding C++11 classes.

struct Mutex {

Mutex() { InitializeCriticalSection(&cs); }

~Mutex() { DeleteCriticalSection(&cs); }

void lock() { EnterCriticalSection(&cs); }

void unlock() { LeaveCriticalSection(&cs); }

private:

CRITICAL_SECTION cs;

};

typedef std::condition_variable_any ConditionVariable;

#else // Default case: use STL classes

typedef std::mutex Mutex;

typedef std::condition_variable ConditionVariable;

#endif

#endif // #ifndef THREAD_WIN32_H_INCLUDED