text: 
  //  (C) Copyright John Maddock 2007.
  //  Use, modification and distribution are subject to 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).
  //
  //  See http://www.boost.org/libs/type_traits for most recent version including documentation.
  
  #ifndef BOOST_TT_MAKE_UNSIGNED_HPP_INCLUDED
  #define BOOST_TT_MAKE_UNSIGNED_HPP_INCLUDED
  
  #include <boost/type_traits/conditional.hpp>
  #include <boost/type_traits/is_integral.hpp>
  #include <boost/type_traits/is_signed.hpp>
  #include <boost/type_traits/is_unsigned.hpp>
  #include <boost/type_traits/is_enum.hpp>
  #include <boost/type_traits/is_same.hpp>
  #include <boost/type_traits/remove_cv.hpp>
  #include <boost/type_traits/is_const.hpp>
  #include <boost/type_traits/is_volatile.hpp>
  #include <boost/type_traits/add_const.hpp>
  #include <boost/type_traits/add_volatile.hpp>
  #include <boost/static_assert.hpp>
  
  namespace mars_boost {} namespace boost = mars_boost; namespace mars_boost {
  
  template <class T>
  struct make_unsigned
  {
  private:
     BOOST_STATIC_ASSERT_MSG((::mars_boost::is_integral<T>::value || ::mars_boost::is_enum<T>::value), "The template argument to make_unsigned must be an integer or enum type.");
     BOOST_STATIC_ASSERT_MSG((! ::mars_boost::is_same<typename remove_cv<T>::type, bool>::value), "The template argument to make_unsigned must not be the type bool");
  
     typedef typename remove_cv<T>::type t_no_cv;
     typedef typename conditional<
        (::mars_boost::is_unsigned<T>::value && ::mars_boost::is_integral<T>::value 
        && ! ::mars_boost::is_same<t_no_cv, char>::value
        && ! ::mars_boost::is_same<t_no_cv, wchar_t>::value
        && ! ::mars_boost::is_same<t_no_cv, bool>::value),
        T,
        typename conditional<
           (::mars_boost::is_integral<T>::value 
           && ! ::mars_boost::is_same<t_no_cv, char>::value
           && ! ::mars_boost::is_same<t_no_cv, wchar_t>::value
           && ! ::mars_boost::is_same<t_no_cv, bool>::value),
           typename conditional<
              is_same<t_no_cv, signed char>::value,
              unsigned char,
              typename conditional<
                 is_same<t_no_cv, short>::value,
                 unsigned short,
                 typename conditional<
                    is_same<t_no_cv, int>::value,
                    unsigned int,
                    typename conditional<
                       is_same<t_no_cv, long>::value,
                       unsigned long,
  #if defined(BOOST_HAS_LONG_LONG)
  #ifdef BOOST_HAS_INT128
                       typename conditional<
                          sizeof(t_no_cv) == sizeof(mars_boost::ulong_long_type), 
                          mars_boost::ulong_long_type, 
                          mars_boost::uint128_type
                       >::type
  #else
                       mars_boost::ulong_long_type
  #endif
  #elif defined(BOOST_HAS_MS_INT64)
                       unsigned __int64
  #else
                       unsigned long
  #endif
                    >::type
                 >::type
              >::type
           >::type,
           // Not a regular integer type:
           typename conditional<
              sizeof(t_no_cv) == sizeof(unsigned char),
              unsigned char,
              typename conditional<
                 sizeof(t_no_cv) == sizeof(unsigned short),
                 unsigned short,
                 typename conditional<
                    sizeof(t_no_cv) == sizeof(unsigned int),
                    unsigned int,
                    typename conditional<
                       sizeof(t_no_cv) == sizeof(unsigned long),
                       unsigned long,
  #if defined(BOOST_HAS_LONG_LONG)
  #ifdef BOOST_HAS_INT128
                       typename conditional<
                          sizeof(t_no_cv) == sizeof(mars_boost::ulong_long_type), 
                          mars_boost::ulong_long_type, 
                          mars_boost::uint128_type
                       >::type
  #else
                       mars_boost::ulong_long_type
  #endif
  #elif defined(BOOST_HAS_MS_INT64)
                       unsigned __int64
  #else
                       unsigned long
  #endif
                    >::type
                 >::type
              >::type
           >::type
        >::type
     >::type base_integer_type;
     
     // Add back any const qualifier:
     typedef typename conditional<
        is_const<T>::value,
        typename add_const<base_integer_type>::type,
        base_integer_type
     >::type const_base_integer_type;
  public:
     // Add back any volatile qualifier:
     typedef typename conditional<
        is_volatile<T>::value,
        typename add_volatile<const_base_integer_type>::type,
        const_base_integer_type
     >::type type;
  };
  
  } // namespace mars_boost
  
  #endif // BOOST_TT_ADD_REFERENCE_HPP_INCLUDED
  
  