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// $Id$
14// $Date$
15// $Revision$
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(BOOST_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
117

source code of include/boost/mpl/vector/aux_/at.hpp