Simple logger for C++ like qDebug()

logger.h

#pragma once
#include <ostream>
#include <sstream>

class logstream
{
private:	
	int _logLevel;
	
	struct log_buf
	{
		std::stringstream m_Stream;
		int ref;	
		log_buf(): ref(1) {}

	} *_logbuf;
public:
	enum 
	{
		LOG_ERROR = 0, 
		LOG_WARNING = 1, 
		LOG_INFORMATION = 2
	};
	static int GLOBAL_LOG_LEVEL;
	
	logstream() : _logbuf(new log_buf) { }
	logstream(int logLevel) : _logLevel(logLevel), _logbuf(new log_buf()) { }
	logstream(const logstream& logStream) : _logbuf(logStream._logbuf) { ++_logbuf->ref; }
	~logstream()
	{
		if(!--_logbuf->ref)
		{
			if(GLOBAL_LOG_LEVEL >= _logLevel)
			{
				AddLog(_logbuf->m_Stream.str().c_str());
				_logbuf->m_Stream.str("");
			}
		}
		delete _logbuf;
	}

	template<class T>
	logstream& operator << (T& s)
	{
		_logbuf->m_Stream << s;
		return *this;
	}

	logstream& operator << (int s)
	{
		_logbuf->m_Stream << s;
		return *this;
	}

	logstream& operator << (long s)
	{
		_logbuf->m_Stream << s;
		return *this;
	}

	logstream& operator << (__int64 s)
	{
		_logbuf->m_Stream << s;
		return *this;
	}

	logstream& operator << (double s)
	{
		_logbuf->m_Stream << s;
		return *this;
	}

	template<>
	logstream& operator << (CString& s)
	{
		_logbuf->m_Stream << s.GetBuffer();
		return *this;
	}
};

int logstream::GLOBAL_LOG_LEVEL = logstream::LOG_INFORMATION;

void LogSetLevel(int logLevel)
{
	logstream::GLOBAL_LOG_LEVEL = logLevel;
}

logstream Log()
{	
	return logstream();
}

logstream LogE()
{
	return logstream(logstream::LOG_ERROR);
}

logstream LogW()
{
	return logstream(logstream::LOG_WARNING);
}

logstream LogI()
{
	return logstream(logstream::LOG_INFORMATION);
}