Chris@16: 
Chris@16: #ifndef BOOST_MPL_VECTOR_AUX_AT_HPP_INCLUDED
Chris@16: #define BOOST_MPL_VECTOR_AUX_AT_HPP_INCLUDED
Chris@16: 
Chris@16: // Copyright Aleksey Gurtovoy 2000-2004
Chris@16: //
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: // See http://www.boost.org/libs/mpl for documentation.
Chris@16: 
Chris@101: // $Id$
Chris@101: // $Date$
Chris@101: // $Revision$
Chris@16: 
Chris@16: #include <boost/mpl/at_fwd.hpp>
Chris@16: #include <boost/mpl/vector/aux_/tag.hpp>
Chris@16: #include <boost/mpl/long.hpp>
Chris@16: #include <boost/mpl/void.hpp>
Chris@16: #include <boost/mpl/aux_/nttp_decl.hpp>
Chris@16: #include <boost/mpl/aux_/type_wrapper.hpp>
Chris@16: #include <boost/mpl/aux_/value_wknd.hpp>
Chris@16: #include <boost/mpl/aux_/config/typeof.hpp>
Chris@16: #include <boost/mpl/aux_/config/ctps.hpp>
Chris@16: 
Chris@16: namespace boost { namespace mpl {
Chris@16: 
Chris@16: #if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
Chris@16: 
Chris@16: template< typename Vector, long n_ >
Chris@16: struct v_at_impl
Chris@16: {
Chris@16:     typedef long_< (Vector::lower_bound_::value + n_) > index_;
Chris@16:     typedef __typeof__( Vector::item_(index_()) ) type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: template< typename Vector, long n_ >
Chris@16: struct v_at
Chris@16:     : aux::wrapped_type< typename v_at_impl<Vector,n_>::type >
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: template<>
Chris@16: struct at_impl< aux::vector_tag >
Chris@16: {
Chris@16:     template< typename Vector, typename N > struct apply
Chris@16:         : v_at<
Chris@16:               Vector
Chris@16:             , BOOST_MPL_AUX_VALUE_WKND(N)::value
Chris@16:             >
Chris@16:     {
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: #else
Chris@16: 
Chris@16: #   if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \
Chris@16:     && !defined(BOOST_MPL_CFG_NO_NONTYPE_TEMPLATE_PARTIAL_SPEC)
Chris@16: 
Chris@16: template< typename Vector, BOOST_MPL_AUX_NTTP_DECL(long, n_) > struct v_at;
Chris@16: 
Chris@16: template< BOOST_MPL_AUX_NTTP_DECL(long, n_) >
Chris@16: struct at_impl< aux::vector_tag<n_> >
Chris@16: {
Chris@16:     template< typename Vector, typename N > struct apply
Chris@16: #if !defined(__BORLANDC__)
Chris@16:         : v_at<
Chris@16:               Vector
Chris@16:             , BOOST_MPL_AUX_VALUE_WKND(N)::value
Chris@16:             >
Chris@16:     {
Chris@16: #else
Chris@16:     {
Chris@16:         typedef typename v_at<
Chris@16:               Vector
Chris@16:             , BOOST_MPL_AUX_VALUE_WKND(N)::value
Chris@16:             >::type type;
Chris@16: #endif
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: #   else
Chris@16: 
Chris@16: namespace aux {
Chris@16: 
Chris@16: template< BOOST_MPL_AUX_NTTP_DECL(long, n_) > struct v_at_impl
Chris@16: {
Chris@16:     template< typename V > struct result_;
Chris@16: };
Chris@16: 
Chris@16: // to work around ETI, etc.
Chris@16: template<> struct v_at_impl<-1>
Chris@16: {
Chris@16:     template< typename V > struct result_
Chris@16:     {
Chris@16:         typedef void_ type;
Chris@16:     };
Chris@16: };
Chris@16: 
Chris@16: } // namespace aux
Chris@16: 
Chris@16: template< typename T, BOOST_MPL_AUX_NTTP_DECL(long, n_) >
Chris@16: struct v_at
Chris@16:     : aux::v_at_impl<n_>::template result_<T>
Chris@16: {
Chris@16: };
Chris@16: 
Chris@16: #   endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
Chris@16: 
Chris@16: #endif // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES
Chris@16: 
Chris@16: }}
Chris@16: 
Chris@16: #endif // BOOST_MPL_VECTOR_AUX_AT_HPP_INCLUDED