/extlibs/Boost/include/boost/mpl/vector/aux_/at.hpp

  1
  2#ifndef BOOST_MPL_VECTOR_AUX_AT_HPP_INCLUDED
  3#define BOOST_MPL_VECTOR_AUX_AT_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: at.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
 14// $Date: 2008-10-11 02:19:02 -0400 (Sat, 11 Oct 2008) $
 15// $Revision: 49267 $
 16
 17#include <boost/mpl/at_fwd.hpp>
 18#include <boost/mpl/vector/aux_/tag.hpp>
 19#include <boost/mpl/long.hpp>
 20#include <boost/mpl/void.hpp>
 21#include <boost/mpl/aux_/nttp_decl.hpp>
 22#include <boost/mpl/aux_/type_wrapper.hpp>
 23#include <boost/mpl/aux_/value_wknd.hpp>
 24#include <boost/mpl/aux_/config/typeof.hpp>
 25#include <boost/mpl/aux_/config/ctps.hpp>
 26
 27namespace boost { namespace mpl {
 28
 29#if defined(BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES)
 30
 31template< typename Vector, long n_ >
 32struct v_at_impl
 33{
 34    typedef long_< (Vector::lower_bound_::value + n_) > index_;
 35    typedef __typeof__( Vector::item_(index_()) ) type;
 36};
 37
 38
 39template< typename Vector, long n_ >
 40struct v_at
 41    : aux::wrapped_type< typename v_at_impl<Vector,n_>::type >
 42{
 43};
 44
 45template<>
 46struct at_impl< aux::vector_tag >
 47{
 48    template< typename Vector, typename N > struct apply
 49        : v_at<
 50              Vector
 51            , BOOST_MPL_AUX_VALUE_WKND(N)::value
 52            >
 53    {
 54    };
 55};
 56
 57#else
 58
 59#   if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION) \
 60    && !defined(BOOST_MPL_CFG_NO_NONTYPE_TEMPLATE_PARTIAL_SPEC)
 61
 62template< typename Vector, BOOST_MPL_AUX_NTTP_DECL(long, n_) > struct v_at;
 63
 64template< BOOST_MPL_AUX_NTTP_DECL(long, n_) >
 65struct at_impl< aux::vector_tag<n_> >
 66{
 67    template< typename Vector, typename N > struct apply
 68#if !defined(__BORLANDC__)
 69        : v_at<
 70              Vector
 71            , BOOST_MPL_AUX_VALUE_WKND(N)::value
 72            >
 73    {
 74#else
 75    {
 76        typedef typename v_at<
 77              Vector
 78            , BOOST_MPL_AUX_VALUE_WKND(N)::value
 79            >::type type;
 80#endif
 81    };
 82};
 83
 84#   else
 85
 86namespace aux {
 87
 88template< BOOST_MPL_AUX_NTTP_DECL(long, n_) > struct v_at_impl
 89{
 90    template< typename V > struct result_;
 91};
 92
 93// to work around ETI, etc.
 94template<> struct v_at_impl<-1>
 95{
 96    template< typename V > struct result_
 97    {
 98        typedef void_ type;
 99    };
100};
101
102} // namespace aux
103
104template< typename T, BOOST_MPL_AUX_NTTP_DECL(long, n_) >
105struct v_at
106    : aux::v_at_impl<n_>::template result_<T>
107{
108};
109
110#   endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
111
112#endif // BOOST_MPL_CFG_TYPEOF_BASED_SEQUENCES
113
114}}
115
116#endif // BOOST_MPL_VECTOR_AUX_AT_HPP_INCLUDED