// Copyright Aleksey Gurtovoy 2001-2004 // // 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) // // See http://www.boost.org/libs/mpl for documentation. // $Id: integer.cpp 49268 2008-10-11 06:26:17Z agurtovoy $ // $Date: 2008-10-11 02:26:17 -0400 (Sat, 11 Oct 2008) $ // $Revision: 49268 $ #include <boost/mpl/multiplies.hpp> #include <boost/mpl/list.hpp> #include <boost/mpl/lower_bound.hpp> #include <boost/mpl/transform_view.hpp> #include <boost/mpl/sizeof.hpp> #include <boost/mpl/int.hpp> #include <boost/mpl/identity.hpp> #include <boost/mpl/base.hpp> #include <boost/mpl/eval_if.hpp> #include <boost/mpl/deref.hpp> #include <boost/mpl/begin_end.hpp> #include <boost/mpl/assert.hpp> #include <boost/type_traits/is_same.hpp> namespace mpl = boost::mpl; using namespace mpl::placeholders; template< int bit_size > class big_int { // ... }; template< int bit_size > struct integer { typedef mpl::list<char,short,int,long> builtins_; typedef typename mpl::base< typename mpl::lower_bound< mpl::transform_view< builtins_ , mpl::multiplies< mpl::sizeof_<_1>, mpl::int_<8> > > , mpl::int_<bit_size> >::type >::type iter_; typedef typename mpl::end<builtins_>::type last_; typedef typename mpl::eval_if< boost::is_same<iter_,last_> , mpl::identity< big_int<bit_size> > , mpl::deref<iter_> >::type type; }; typedef integer<1>::type int1; typedef integer<5>::type int5; typedef integer<15>::type int15; typedef integer<32>::type int32; typedef integer<100>::type int100; BOOST_MPL_ASSERT(( boost::is_same< int1, char > )); BOOST_MPL_ASSERT(( boost::is_same< int5, char > )); BOOST_MPL_ASSERT(( boost::is_same< int15, short > )); BOOST_MPL_ASSERT(( boost::is_same< int32, int > )); BOOST_MPL_ASSERT(( boost::is_same< int100, big_int<100> > ));