1 
2 #ifndef BOOST_MPL_O1_SIZE_IMPL_HPP_INCLUDED
3 #define BOOST_MPL_O1_SIZE_IMPL_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: O1_size_impl.hpp 49267 2008-10-11 06:19:02Z agurtovoy $
14 // $Date: 2008-10-10 23:19:02 -0700 (Fri, 10 Oct 2008) $
15 // $Revision: 49267 $
16 
17 #include <boost/mpl/O1_size_fwd.hpp>
18 #include <boost/mpl/long.hpp>
19 #include <boost/mpl/if.hpp>
20 #include <boost/mpl/aux_/has_size.hpp>
21 #include <boost/mpl/aux_/config/forwarding.hpp>
22 #include <boost/mpl/aux_/config/static_constant.hpp>
23 #include <boost/mpl/aux_/config/msvc.hpp>
24 #include <boost/mpl/aux_/config/workaround.hpp>
25 
26 namespace boost { namespace mpl {
27 
28 // default implementation - returns 'Sequence::size' if sequence has a 'size'
29 // member, and -1 otherwise; conrete sequences might override it by
30 // specializing either the 'O1_size_impl' or the primary 'O1_size' template
31 
32 #   if !BOOST_WORKAROUND(BOOST_MSVC, < 1300) \
33     && !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
34 
35 namespace aux {
36 template< typename Sequence > struct O1_size_impl
37     : Sequence::size
38 {
39 };
40 }
41 
42 template< typename Tag >
43 struct O1_size_impl
44 {
45     template< typename Sequence > struct apply
46 #if !defined(BOOST_MPL_CFG_NO_NESTED_FORWARDING)
47         : if_<
48               aux::has_size<Sequence>
49             , aux::O1_size_impl<Sequence>
50             , long_<-1>
51             >::type
52     {
53 #else
54     {
55         typedef typename if_<
56               aux::has_size<Sequence>
57             , aux::O1_size_impl<Sequence>
58             , long_<-1>
59             >::type type;
60 
61         BOOST_STATIC_CONSTANT(long, value =
62               (if_<
63                   aux::has_size<Sequence>
64                 , aux::O1_size_impl<Sequence>
65                 , long_<-1>
66                 >::type::value)
67             );
68 #endif
69     };
70 };
71 
72 #   else // BOOST_MSVC
73 
74 template< typename Tag >
75 struct O1_size_impl
76 {
77     template< typename Sequence > struct apply
78         : long_<-1>
79         {
80         };
81 };
82 
83 #   endif
84 
85 }}
86 
87 #endif // BOOST_MPL_O1_SIZE_IMPL_HPP_INCLUDED
88