/*
|
* Copyright Andrey Semashev 2007 - 2015.
|
* 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)
|
*/
|
/*!
|
* \file counter.hpp
|
* \author Andrey Semashev
|
* \date 01.05.2007
|
*
|
* The header contains implementation of the counter attribute.
|
*/
|
|
#ifndef BOOST_LOG_ATTRIBUTES_COUNTER_HPP_INCLUDED_
|
#define BOOST_LOG_ATTRIBUTES_COUNTER_HPP_INCLUDED_
|
|
#include <boost/static_assert.hpp>
|
#include <boost/type_traits/is_integral.hpp>
|
#include <boost/log/detail/config.hpp>
|
#include <boost/log/attributes/attribute.hpp>
|
#include <boost/log/attributes/attribute_cast.hpp>
|
#include <boost/log/attributes/attribute_value_impl.hpp>
|
#ifndef BOOST_LOG_NO_THREADS
|
#include <boost/memory_order.hpp>
|
#include <boost/atomic/atomic.hpp>
|
#endif // BOOST_LOG_NO_THREADS
|
#include <boost/log/detail/header.hpp>
|
|
#ifdef BOOST_HAS_PRAGMA_ONCE
|
#pragma once
|
#endif
|
|
namespace boost {
|
|
BOOST_LOG_OPEN_NAMESPACE
|
|
namespace attributes {
|
|
/*!
|
* \brief A class of an attribute that counts an integral value
|
*
|
* This attribute acts as a counter - it returns a monotonously
|
* changing value each time requested. The attribute value type can be specified
|
* as a template parameter. The type must be an integral type.
|
*/
|
template< typename T >
|
class counter :
|
public attribute
|
{
|
BOOST_STATIC_ASSERT_MSG(is_integral< T >::value, "Boost.Log: Only integral types are supported by the counter attribute");
|
|
public:
|
//! A counter value type
|
typedef T value_type;
|
|
protected:
|
//! Factory implementation
|
class BOOST_SYMBOL_VISIBLE impl :
|
public attribute::impl
|
{
|
private:
|
#ifndef BOOST_LOG_NO_THREADS
|
boost::atomic< value_type > m_counter;
|
#else
|
value_type m_counter;
|
#endif
|
const value_type m_step;
|
|
public:
|
impl(value_type initial, value_type step) BOOST_NOEXCEPT :
|
m_counter(initial), m_step(step)
|
{
|
}
|
|
attribute_value get_value()
|
{
|
#ifndef BOOST_LOG_NO_THREADS
|
value_type value = m_counter.fetch_add(m_step, boost::memory_order_relaxed);
|
#else
|
value_type value = m_counter;
|
m_counter += m_step;
|
#endif
|
return make_attribute_value(value);
|
}
|
};
|
|
public:
|
/*!
|
* Constructor
|
*
|
* \param initial Initial value of the counter
|
* \param step Changing step of the counter. Each value acquired from the attribute
|
* will be greater than the previous one by this amount.
|
*/
|
explicit counter(value_type initial = (value_type)0, value_type step = (value_type)1) :
|
attribute(new impl(initial, step))
|
{
|
}
|
|
/*!
|
* Constructor for casting support
|
*/
|
explicit counter(cast_source const& source) :
|
attribute(source.as< impl >())
|
{
|
}
|
};
|
|
} // namespace attributes
|
|
BOOST_LOG_CLOSE_NAMESPACE // namespace log
|
|
} // namespace boost
|
|
#include <boost/log/detail/footer.hpp>
|
|
#endif // BOOST_LOG_ATTRIBUTES_COUNTER_HPP_INCLUDED_
|
