williamr@4: 
williamr@4: #ifndef BOOST_MPL_VECTOR_AUX_AT_HPP_INCLUDED
williamr@4: #define BOOST_MPL_VECTOR_AUX_AT_HPP_INCLUDED
williamr@4: 
williamr@4: // Copyright Aleksey Gurtovoy 2000-2004
williamr@4: //
williamr@4: // Distributed under the Boost Software License, Version 1.0. 
williamr@4: // (See accompanying file LICENSE_1_0.txt or copy at 
williamr@4: // http://www.boost.org/LICENSE_1_0.txt)
williamr@4: //
williamr@4: // See http://www.boost.org/libs/mpl for documentation.
williamr@4: 
williamr@4: // $Source: /cvsroot/boost/boost/boost/mpl/vector/aux_/at.hpp,v $
williamr@4: // $Date: 2004/12/20 19:35:33 $
williamr@4: // $Revision: 1.6 $
williamr@4: 
williamr@4: #include <boost/mpl/at_fwd.hpp>
williamr@4: #include <boost/mpl/vector/aux_/tag.hpp>
williamr@4: #include <boost/mpl/long.hpp>
williamr@4: #include <boost/mpl/void.hpp>
williamr@4: #include <boost/mpl/aux_/nttp_decl.hpp>
williamr@4: #include <boost/mpl/aux_/type_wrapper.hpp>
williamr@4: #include <boost/mpl/aux_/value_wknd.hpp>
williamr@4: #include <boost/mpl/aux_/config/typeof.hpp>
williamr@4: #include <boost/mpl/aux_/config/ctps.hpp>
williamr@4: 
williamr@4: namespace boost { namespace mpl {
williamr@4: 
williamr@4: #if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
williamr@4: 
williamr@4: template< typename Vector, long n_ >
williamr@4: struct v_at_impl
williamr@4: {
williamr@4:     typedef long_< (Vector::lower_bound_::value + n_) > index_;
williamr@4:     typedef __typeof__( Vector::item_(index_()) ) type;
williamr@4: };
williamr@4: 
williamr@4: 
williamr@4: template< typename Vector, long n_ >
williamr@4: struct v_at
williamr@4:     : aux::wrapped_type< typename v_at_impl<Vector,n_>::type >
williamr@4: {
williamr@4: };
williamr@4: 
williamr@4: template<>
williamr@4: struct at_impl< aux::vector_tag >
williamr@4: {
williamr@4:     template< typename Vector, typename N > struct apply
williamr@4:         : v_at<
williamr@4:               Vector
williamr@4:             , BOOST_MPL_AUX_VALUE_WKND(N)::value
williamr@4:             >
williamr@4:     {
williamr@4:     };
williamr@4: };
williamr@4: 
williamr@4: #else
williamr@4: 
williamr@4: #   if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \
williamr@4:     && !defined(BOOST_MPL_CFG_NO_NONTYPE_TEMPLATE_PARTIAL_SPEC)
williamr@4: 
williamr@4: template< typename Vector, BOOST_MPL_AUX_NTTP_DECL(long, n_) > struct v_at;
williamr@4: 
williamr@4: template< BOOST_MPL_AUX_NTTP_DECL(long, n_) >
williamr@4: struct at_impl< aux::vector_tag<n_> >
williamr@4: {
williamr@4:     template< typename Vector, typename N > struct apply
williamr@4: #if !defined(__BORLANDC__)
williamr@4:         : v_at<
williamr@4:               Vector
williamr@4:             , BOOST_MPL_AUX_VALUE_WKND(N)::value
williamr@4:             >
williamr@4:     {
williamr@4: #else
williamr@4:     {
williamr@4:         typedef typename v_at<
williamr@4:               Vector
williamr@4:             , BOOST_MPL_AUX_VALUE_WKND(N)::value
williamr@4:             >::type type;
williamr@4: #endif
williamr@4:     };
williamr@4: };
williamr@4: 
williamr@4: #   else
williamr@4: 
williamr@4: namespace aux {
williamr@4: 
williamr@4: template< BOOST_MPL_AUX_NTTP_DECL(long, n_) > struct v_at_impl
williamr@4: {
williamr@4:     template< typename V > struct result_;
williamr@4: };
williamr@4: 
williamr@4: // to work around ETI, etc.
williamr@4: template<> struct v_at_impl<-1>
williamr@4: {
williamr@4:     template< typename V > struct result_
williamr@4:     {
williamr@4:         typedef void_ type;
williamr@4:     };
williamr@4: };
williamr@4: 
williamr@4: } // namespace aux
williamr@4: 
williamr@4: template< typename T, BOOST_MPL_AUX_NTTP_DECL(long, n_) >
williamr@4: struct v_at
williamr@4:     : aux::v_at_impl<n_>::template result_<T>
williamr@4: {
williamr@4: };
williamr@4: 
williamr@4: #   endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@4: 
williamr@4: #endif // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES
williamr@4: 
williamr@4: }}
williamr@4: 
williamr@4: #endif // BOOST_MPL_VECTOR_AUX_AT_HPP_INCLUDED