boost/log/attributes/attribute_name.hpp
/*
* Copyright Andrey Semashev 2007 - 2014.
* 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 attribute_name.hpp
* \author Andrey Semashev
* \date 28.06.2010
*
* The header contains attribute name interface definition.
*/
#ifndef BOOST_LOG_ATTRIBUTE_NAME_HPP_INCLUDED_
#define BOOST_LOG_ATTRIBUTE_NAME_HPP_INCLUDED_
#include <iosfwd>
#include <string>
#include <boost/assert.hpp>
#include <boost/cstdint.hpp>
#include <boost/log/detail/config.hpp>
#include <boost/utility/explicit_operator_bool.hpp>
#include <boost/log/detail/header.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
namespace boost {
BOOST_LOG_OPEN_NAMESPACE
/*!
* \brief The class represents an attribute name in containers used by the library
*
* The class mostly serves for optimization purposes. Each attribute name that is used
* with the library is automatically associated with a unique identifier, which is much
* lighter in terms of memory footprint and operations complexity. This is done
* transparently by this class, on object construction. Passing objects of this class
* to other library methods, such as attribute lookup functions, will not require
* this translation and/or string copying and thus will result in a more efficient code.
*/
class attribute_name
{
public:
//! String type
typedef std::string string_type;
#ifdef BOOST_LOG_DOXYGEN_PASS
//! Associated identifier
typedef unspecified id_type;
#else
typedef uint32_t id_type;
private:
enum { uninitialized = 0xFFFFFFFFu };
class repository;
friend class repository;
private:
//! Associated identifier
id_type m_id;
#endif
public:
/*!
* Default constructor. Creates an object that does not refer to any attribute name.
*/
BOOST_CONSTEXPR attribute_name() BOOST_NOEXCEPT : m_id(static_cast< id_type >(uninitialized))
{
}
/*!
* Constructs an attribute name from the specified string
*
* \param name An attribute name
* \pre \a name is not NULL and points to a zero-terminated string
*/
attribute_name(const char* name) :
m_id(get_id_from_string(name))
{
}
/*!
* Constructs an attribute name from the specified string
*
* \param name An attribute name
*/
attribute_name(string_type const& name) :
m_id(get_id_from_string(name.c_str()))
{
}
/*!
* Compares the attribute names
*
* \return \c true if <tt>*this</tt> and \c that refer to the same attribute name,
* and \c false otherwise.
*/
bool operator== (attribute_name const& that) const BOOST_NOEXCEPT { return m_id == that.m_id; }
/*!
* Compares the attribute names
*
* \return \c true if <tt>*this</tt> and \c that refer to different attribute names,
* and \c false otherwise.
*/
bool operator!= (attribute_name const& that) const BOOST_NOEXCEPT { return m_id != that.m_id; }
/*!
* Compares the attribute names
*
* \return \c true if <tt>*this</tt> and \c that refer to the same attribute name,
* and \c false otherwise.
*/
bool operator== (const char* that) const { return (m_id != static_cast< id_type >(uninitialized)) && (this->string() == that); }
/*!
* Compares the attribute names
*
* \return \c true if <tt>*this</tt> and \c that refer to different attribute names,
* and \c false otherwise.
*/
bool operator!= (const char* that) const { return !operator== (that); }
/*!
* Compares the attribute names
*
* \return \c true if <tt>*this</tt> and \c that refer to the same attribute name,
* and \c false otherwise.
*/
bool operator== (string_type const& that) const { return (m_id != static_cast< id_type >(uninitialized)) && (this->string() == that); }
/*!
* Compares the attribute names
*
* \return \c true if <tt>*this</tt> and \c that refer to different attribute names,
* and \c false otherwise.
*/
bool operator!= (string_type const& that) const { return !operator== (that); }
/*!
* Checks if the object was default-constructed
*
* \return \c true if <tt>*this</tt> was constructed with an attribute name, \c false otherwise
*/
BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()
/*!
* Checks if the object was default-constructed
*
* \return \c true if <tt>*this</tt> was default-constructed and does not refer to any attribute name,
* \c false otherwise
*/
bool operator! () const BOOST_NOEXCEPT { return (m_id == static_cast< id_type >(uninitialized)); }
/*!
* \return The associated id value
* \pre <tt>(!*this) == false</tt>
*/
id_type id() const BOOST_NOEXCEPT
{
BOOST_ASSERT(m_id != static_cast< id_type >(uninitialized));
return m_id;
}
/*!
* \return The attribute name string that was used during the object construction
* \pre <tt>(!*this) == false</tt>
*/
string_type const& string() const { return get_string_from_id(m_id); }
private:
#ifndef BOOST_LOG_DOXYGEN_PASS
static BOOST_LOG_API id_type get_id_from_string(const char* name);
static BOOST_LOG_API string_type const& get_string_from_id(id_type id);
#endif
};
template< typename CharT, typename TraitsT >
BOOST_LOG_API std::basic_ostream< CharT, TraitsT >& operator<< (
std::basic_ostream< CharT, TraitsT >& strm,
attribute_name const& name);
BOOST_LOG_CLOSE_NAMESPACE // namespace log
} // namespace boost
#include <boost/log/detail/footer.hpp>
#endif // BOOST_LOG_ATTRIBUTE_NAME_HPP_INCLUDED_