70 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
		
		
			
		
	
	
			70 lines
		
	
	
		
			1.8 KiB
		
	
	
	
		
			Plaintext
		
	
	
	
	
	
|   | 
 | ||
|  | #ifndef BOOST_MPL_AUX_ERASE_IMPL_HPP_INCLUDED | ||
|  | #define BOOST_MPL_AUX_ERASE_IMPL_HPP_INCLUDED | ||
|  | 
 | ||
|  | // Copyright Aleksey Gurtovoy 2000-2004 | ||
|  | // | ||
|  | // Distributed under the Boost Software License, Version 1.0.  | ||
|  | // (See accompanying file LICENSE_1_0.txt or copy at  | ||
|  | // http://www.boost.org/LICENSE_1_0.txt) | ||
|  | // | ||
|  | // See http://www.boost.org/libs/mpl for documentation. | ||
|  | 
 | ||
|  | // $Id$ | ||
|  | // $Date$ | ||
|  | // $Revision$ | ||
|  | 
 | ||
|  | #include <boost/mpl/clear.hpp> | ||
|  | #include <boost/mpl/push_front.hpp> | ||
|  | #include <boost/mpl/reverse_fold.hpp> | ||
|  | #include <boost/mpl/iterator_range.hpp> | ||
|  | #include <boost/mpl/next.hpp> | ||
|  | #include <boost/mpl/aux_/na.hpp> | ||
|  | 
 | ||
|  | namespace boost { namespace mpl { | ||
|  | 
 | ||
|  | // default implementation; conrete sequences might override it by  | ||
|  | // specializing either the 'erase_impl' or the primary 'erase' template | ||
|  | 
 | ||
|  | template< typename Tag > | ||
|  | struct erase_impl | ||
|  | { | ||
|  |     template< | ||
|  |           typename Sequence | ||
|  |         , typename First | ||
|  |         , typename Last | ||
|  |         > | ||
|  |     struct apply | ||
|  |     { | ||
|  |         typedef typename if_na< Last,typename next<First>::type >::type last_; | ||
|  |          | ||
|  |         // 1st half: [begin, first) | ||
|  |         typedef iterator_range< | ||
|  |               typename begin<Sequence>::type | ||
|  |             , First | ||
|  |             > first_half_; | ||
|  | 
 | ||
|  |         // 2nd half: [last, end) ... that is, [last + 1, end) | ||
|  |         typedef iterator_range< | ||
|  |               last_ | ||
|  |             , typename end<Sequence>::type | ||
|  |             > second_half_; | ||
|  | 
 | ||
|  |         typedef typename reverse_fold< | ||
|  |               second_half_ | ||
|  |             , typename clear<Sequence>::type | ||
|  |             , push_front<_,_> | ||
|  |             >::type half_sequence_; | ||
|  | 
 | ||
|  |         typedef typename reverse_fold< | ||
|  |               first_half_ | ||
|  |             , half_sequence_ | ||
|  |             , push_front<_,_> | ||
|  |             >::type type; | ||
|  |     }; | ||
|  | }; | ||
|  | 
 | ||
|  | }} | ||
|  | 
 | ||
|  | #endif // BOOST_MPL_AUX_ERASE_IMPL_HPP_INCLUDED |