Re: [boost] Re: sizeof_array?

From: Daniel Frey (daniel.frey_at_[hidden])
Date: 2002-06-27 01:57:48

Gennaro Prota wrote:
> 
> [Cool idea snipped]
> But I suspect there's not much interest in this.

At least it integrates with the current version easily:

--- declare array_traits like this (directly after 'namespace boost')
---
   template< typename T, int D = 0 > class array_traits
   {
   private:
      BOOST_STATIC_ASSERT( ::boost::is_array< T >::value );
      typedef typename remove_bounds< T >::type base_type;
   public:
      typedef typename array_traits< base_type, D-1 >::value_type
value_type;
      typedef typename array_traits< base_type, D-1 >::iterator
iterator;
      typedef typename array_traits< base_type, D-1 >::reference
reference;
      BOOST_STATIC_CONSTANT( std::size_t, size = sizeof( base_type ) /
sizeof( value_type ) );
   };
--- make the old array_traits a specialization:
   
   template< typename T > class array_traits< T, 0 >
   {
      ...unchanged from previous version...
   };
--- Add these functions where they belong ---
   template< int D, typename T >
   std::size_t
   inline array_size( T& )
   {
      return ::boost::array_traits< T, D >::size;
   }
   
   template< int D, typename T, std::size_t N >
   const char ( &array_to_sizeof( T(&)[N] ) )[ array_traits< D, T[N]
>::size ];
   template< int D, typename T, std::size_t N >
   const char ( &array_to_sizeof( const T(&)[N] ) )[ array_traits< D,
T[N] >::size ];
   template< int D, typename T, std::size_t N >
   const char ( &array_to_sizeof( volatile T(&)[N] ) )[ array_traits< D,
T[N] >::size ];
   template< int D, typename T, std::size_t N >
   const char ( &array_to_sizeof( const volatile T(&)[N] ) )[
array_traits< D, T[N] >::size ];
   ...
}
Merging it with the old source should be a problem, if it is, I could
post the complete code again...
The question that remains is: Is it useful? Does it have a good syntax?
Regards, Daniel
--
Daniel Frey
aixigo AG - financial training, research and technology
Schloß-Rahe-Straße 15, 52072 Aachen, Germany
fon: [phone], fax: [phone]
eMail: daniel.frey_at_[hidden], web: http://www.aixigo.de