1 2 #ifndef BOOST_MPL_DISTANCE_HPP_INCLUDED 3 #define BOOST_MPL_DISTANCE_HPP_INCLUDED 4 5 // Copyright Aleksey Gurtovoy 2000-2004 6 // 7 // Distributed under the Boost Software License, Version 1.0. 8 // (See accompanying file LICENSE_1_0.txt or copy at 9 // http://www.boost.org/LICENSE_1_0.txt) 10 // 11 // See http://www.boost.org/libs/mpl for documentation. 12 13 // $Id$ 14 // $Date$ 15 // $Revision$ 16 17 #include <boost/mpl/distance_fwd.hpp> 18 #include <boost/mpl/iter_fold.hpp> 19 #include <boost/mpl/iterator_range.hpp> 20 #include <boost/mpl/long.hpp> 21 #include <boost/mpl/next.hpp> 22 #include <boost/mpl/tag.hpp> 23 #include <boost/mpl/apply_wrap.hpp> 24 #include <boost/mpl/aux_/msvc_eti_base.hpp> 25 #include <boost/mpl/aux_/value_wknd.hpp> 26 #include <boost/mpl/aux_/na_spec.hpp> 27 #include <boost/mpl/aux_/config/forwarding.hpp> 28 #include <boost/mpl/aux_/config/static_constant.hpp> 29 30 31 namespace boost { namespace mpl { 32 33 // default implementation for forward/bidirectional iterators 34 template< typename Tag > struct distance_impl 35 { 36 template< typename First, typename Last > struct apply 37 #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING) 38 : aux::msvc_eti_base< typename iter_fold< 39 iterator_range<First,Last> 40 , mpl::long_<0> 41 , next<> 42 >::type > 43 { 44 #else 45 { 46 typedef typename iter_fold< 47 iterator_range<First,Last> 48 , mpl::long_<0> 49 , next<> 50 >::type type; 51 52 BOOST_STATIC_CONSTANT(long, value = 53 (iter_fold< 54 iterator_range<First,Last> 55 , mpl::long_<0> 56 , next<> 57 >::type::value) 58 ); 59 #endif 60 }; 61 }; 62 63 template< 64 typename BOOST_MPL_AUX_NA_PARAM(First) 65 , typename BOOST_MPL_AUX_NA_PARAM(Last) 66 > 67 struct distance 68 : distance_impl< typename tag<First>::type > 69 ::template apply<First, Last> 70 { 71 BOOST_MPL_AUX_LAMBDA_SUPPORT(2, distance, (First, Last)) 72 }; 73 74 BOOST_MPL_AUX_NA_SPEC(2, distance) 75 76 }} 77 78 #endif // BOOST_MPL_DISTANCE_HPP_INCLUDED 79