epoc32/include/stdapis/boost/ptr_container/nullable.hpp
author William Roberts <williamr@symbian.org>
Wed, 31 Mar 2010 12:33:34 +0100
branchSymbian3
changeset 4 837f303aceeb
permissions -rw-r--r--
Current Symbian^3 public API header files (from PDK 3.0.h)
This is the epoc32/include tree with the "platform" subtrees removed, and
all but a selected few mbg and rsg files removed.
     1 //
     2 // Boost.Pointer Container
     3 //
     4 //  Copyright Thorsten Ottosen 2003-2005. Use, modification and
     5 //  distribution is subject to the Boost Software License, Version
     6 //  1.0. (See accompanying file LICENSE_1_0.txt or copy at
     7 //  http://www.boost.org/LICENSE_1_0.txt)
     8 //
     9 // For more information, see http://www.boost.org/libs/ptr_container/
    10 //
    11 
    12 
    13 #ifndef BOOST_INDIRECT_CONTAINER_NULLABLE_HPP
    14 #define BOOST_INDIRECT_CONTAINER_NULLABLE_HPP
    15 
    16 #if defined(_MSC_VER) && (_MSC_VER >= 1200)
    17 # pragma once
    18 #endif
    19 
    20 #include <boost/type_traits/detail/yes_no_type.hpp>
    21 #include <boost/mpl/eval_if.hpp>
    22 #include <boost/mpl/identity.hpp>
    23 #include <boost/config.hpp>
    24 
    25 namespace boost
    26 {
    27     
    28     template< class T >
    29     struct nullable
    30     {
    31         typedef T type;
    32     };   
    33 
    34     namespace ptr_container_detail
    35     {
    36         template< class T >
    37         type_traits::yes_type is_nullable( const nullable<T>* );
    38 
    39         type_traits::no_type is_nullable( ... );        
    40     }
    41 
    42     template< class T >
    43     struct is_nullable
    44     {
    45     private:
    46             BOOST_STATIC_CONSTANT( T*, var );
    47     public:
    48             BOOST_STATIC_CONSTANT(bool, value = sizeof( ptr_container_detail::is_nullable( var ) ) 
    49                                                 == sizeof( type_traits::yes_type ) );
    50     };
    51     
    52     template< class T >
    53     struct remove_nullable
    54     {
    55         typedef BOOST_DEDUCED_TYPENAME mpl::eval_if< is_nullable<T>,
    56                                                       T,
    57                                             mpl::identity<T> >::type
    58             type;
    59     };
    60 
    61 }
    62 
    63 #endif