Chris@16: /*
Chris@101:  *          Copyright Andrey Semashev 2007 - 2015.
Chris@16:  * Distributed under the Boost Software License, Version 1.0.
Chris@16:  *    (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:  *          http://www.boost.org/LICENSE_1_0.txt)
Chris@16:  */
Chris@16: /*!
Chris@16:  * \file   counter.hpp
Chris@16:  * \author Andrey Semashev
Chris@16:  * \date   01.05.2007
Chris@16:  *
Chris@16:  * The header contains implementation of the counter attribute.
Chris@16:  */
Chris@16: 
Chris@16: #ifndef BOOST_LOG_ATTRIBUTES_COUNTER_HPP_INCLUDED_
Chris@16: #define BOOST_LOG_ATTRIBUTES_COUNTER_HPP_INCLUDED_
Chris@16: 
Chris@16: #include <boost/static_assert.hpp>
Chris@16: #include <boost/type_traits/is_integral.hpp>
Chris@16: #include <boost/log/detail/config.hpp>
Chris@16: #include <boost/log/attributes/attribute.hpp>
Chris@16: #include <boost/log/attributes/attribute_cast.hpp>
Chris@16: #include <boost/log/attributes/attribute_value_impl.hpp>
Chris@16: #ifndef BOOST_LOG_NO_THREADS
Chris@16: #include <boost/detail/atomic_count.hpp>
Chris@16: #endif // BOOST_LOG_NO_THREADS
Chris@16: #include <boost/log/detail/header.hpp>
Chris@16: 
Chris@16: #ifdef BOOST_HAS_PRAGMA_ONCE
Chris@16: #pragma once
Chris@16: #endif
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@16: BOOST_LOG_OPEN_NAMESPACE
Chris@16: 
Chris@16: namespace attributes {
Chris@16: 
Chris@16: /*!
Chris@16:  * \brief A class of an attribute that counts an integral value
Chris@16:  *
Chris@16:  * This type of attribute acts as a counter, that is, it returns a monotonously
Chris@16:  * changing value each time requested. The attribute value type can be specified
Chris@16:  * as a template parameter. However, the type must be an integral type of size no
Chris@16:  * more than <tt>sizeof(long)</tt>.
Chris@16:  */
Chris@16: template< typename T >
Chris@16: class counter :
Chris@16:     public attribute
Chris@16: {
Chris@16:     //  For now only integral types up to long are supported
Chris@16:     BOOST_STATIC_ASSERT_MSG(is_integral< T >::value && sizeof(T) <= sizeof(long), "Boost.Log: Only integral types up to long are supported by counter attribute");
Chris@16: 
Chris@16: public:
Chris@16:     //! A counter value type
Chris@16:     typedef T value_type;
Chris@16: 
Chris@16: protected:
Chris@16:     //! Base class for factory implementation
Chris@16:     class BOOST_LOG_NO_VTABLE BOOST_SYMBOL_VISIBLE impl :
Chris@16:         public attribute::impl
Chris@16:     {
Chris@16:     };
Chris@16: 
Chris@16:     //! Generic factory implementation
Chris@16:     class impl_generic;
Chris@16: #ifndef BOOST_LOG_NO_THREADS
Chris@16:     //! Increment-by-one factory implementation
Chris@16:     class impl_inc;
Chris@16:     //! Decrement-by-one factory implementation
Chris@16:     class impl_dec;
Chris@16: #endif
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Constructor
Chris@16:      *
Chris@16:      * \param initial Initial value of the counter
Chris@16:      * \param step Changing step of the counter. Each value acquired from the attribute
Chris@16:      *        will be greater than the previous one to this amount.
Chris@16:      */
Chris@16:     explicit counter(value_type initial = (value_type)0, long step = 1) :
Chris@16: #ifndef BOOST_LOG_NO_THREADS
Chris@16:         attribute()
Chris@16:     {
Chris@16:         if (step == 1)
Chris@16:             this->set_impl(new impl_inc(initial));
Chris@16:         else if (step == -1)
Chris@16:             this->set_impl(new impl_dec(initial));
Chris@16:         else
Chris@16:             this->set_impl(new impl_generic(initial, step));
Chris@16:     }
Chris@16: #else
Chris@16:         attribute(new impl_generic(initial, step))
Chris@16:     {
Chris@16:     }
Chris@16: #endif
Chris@16:     /*!
Chris@16:      * Constructor for casting support
Chris@16:      */
Chris@16:     explicit counter(cast_source const& source) :
Chris@16:         attribute(source.as< impl >())
Chris@16:     {
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: #ifndef BOOST_LOG_NO_THREADS
Chris@16: 
Chris@16: template< typename T >
Chris@16: class counter< T >::impl_generic :
Chris@16:     public impl
Chris@16: {
Chris@16: private:
Chris@16:     //! Initial value
Chris@16:     const value_type m_Initial;
Chris@16:     //! Step value
Chris@16:     const long m_Step;
Chris@16:     //! The counter
Chris@16:     boost::detail::atomic_count m_Counter;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Initializing constructor
Chris@16:      */
Chris@16:     impl_generic(value_type initial, long step) : m_Initial(initial), m_Step(step), m_Counter(-1)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     attribute_value get_value()
Chris@16:     {
Chris@101:         const unsigned long next_counter = static_cast< unsigned long >(++m_Counter);
Chris@101:         value_type next = static_cast< value_type >(m_Initial + (next_counter * m_Step));
Chris@16:         return make_attribute_value(next);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template< typename T >
Chris@16: class counter< T >::impl_inc :
Chris@16:     public impl
Chris@16: {
Chris@16: private:
Chris@16:     //! The counter
Chris@16:     boost::detail::atomic_count m_Counter;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Initializing constructor
Chris@16:      */
Chris@16:     explicit impl_inc(value_type initial) : m_Counter(initial - 1)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     attribute_value get_value()
Chris@16:     {
Chris@16:         return make_attribute_value(static_cast< value_type >(++m_Counter));
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: template< typename T >
Chris@16: class counter< T >::impl_dec :
Chris@16:     public impl
Chris@16: {
Chris@16: private:
Chris@16:     //! The counter
Chris@16:     boost::detail::atomic_count m_Counter;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Initializing constructor
Chris@16:      */
Chris@16:     explicit impl_dec(value_type initial) : m_Counter(initial + 1)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     attribute_value get_value()
Chris@16:     {
Chris@16:         return make_attribute_value(static_cast< value_type >(--m_Counter));
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: #else // BOOST_LOG_NO_THREADS
Chris@16: 
Chris@16: template< typename T >
Chris@16: class counter< T >::impl_generic :
Chris@16:     public impl
Chris@16: {
Chris@16: private:
Chris@16:     //! Step value
Chris@16:     const long m_Step;
Chris@16:     //! The counter
Chris@16:     value_type m_Counter;
Chris@16: 
Chris@16: public:
Chris@16:     /*!
Chris@16:      * Initializing constructor
Chris@16:      */
Chris@16:     impl_generic(value_type initial, long step) : m_Step(step), m_Counter(initial - step)
Chris@16:     {
Chris@16:     }
Chris@16: 
Chris@16:     attribute_value get_value()
Chris@16:     {
Chris@16:         m_Counter += m_Step;
Chris@16:         return make_attribute_value(m_Counter);
Chris@16:     }
Chris@16: };
Chris@16: 
Chris@16: #endif // BOOST_LOG_NO_THREADS
Chris@16: 
Chris@16: } // namespace attributes
Chris@16: 
Chris@16: BOOST_LOG_CLOSE_NAMESPACE // namespace log
Chris@16: 
Chris@16: } // namespace boost
Chris@16: 
Chris@16: #include <boost/log/detail/footer.hpp>
Chris@16: 
Chris@16: #endif // BOOST_LOG_ATTRIBUTES_COUNTER_HPP_INCLUDED_