#ifndef BOOST_WIN32_ONCE_CRITSEC_HPP
#define BOOST_WIN32_ONCE_CRITSEC_HPP

//  once_critsec.hpp
//
//  (C) Copyright 2005 Anthony Williams 
//
//  Distributed under the Boost Software License, Version 1.0. (See
//  accompanying file LICENSE_1_0.txt or copy at
//  http://www.boost.org/LICENSE_1_0.txt)

#include <windows.h>
#include <string>
#include <sstream>
#include <limits.h>

namespace boost
{
	typedef LONG once_flag;

#define BOOST_ONCE_INIT {0}

    namespace detail
    {
        
	class critsec
	{
	public:
		critsec()
		{
			InitializeCriticalSection(&m_critsec);
		}
		~critsec()
		{
			DeleteCriticalSection(&m_critsec);
		}
		void lock()
		{
			EnterCriticalSection(&m_critsec);
		}
		void unlock()
		{
			LeaveCriticalSection(&m_critsec);
		}
	private:
		CRITICAL_SECTION m_critsec;
	};

	class scopedlock
	{
	public:
		scopedlock(critsec & lck)
			: m_lck(lck) 
		{
			m_lck.lock();
		}
		~scopedlock()
		{
			m_lck.unlock();
		}
	private:
		critsec & m_lck;
	};
    }
    

    template<typename Function>
    void call_once(Function f,once_flag& flag)
    {
	static detail::critsec lck;
	detail::scopedlock guard(lck);

	if (!::InterlockedCompareExchange(&flag, 1, 1))
	{
		f();
		::InterlockedExchange(&flag, 1);
	}
    }
}

#endif