Use when a built-in array types needs extents to be stripped, but the amount to strip is between one and all (exclusive). I thought I needed this for another project, but I ended up not needing it (yet). So it's here so I won't forget, and for posterity.

remove_some_extents.cpp

//  Copyright 2013 Daryle Walker.
//  Distributed under the Boost Software License, Version 1.0.  (See a copy at
//  <http://www.boost.org/LICENSE_1_0.txt>.)

#ifndef REMOVE_SOME_EXTENTS_HPP
#define REMOVE_SOME_EXTENTS_HPP

#include <cstddef>


//  Forward declarations  ----------------------------------------------------//

/** \brief  Type-traits for removing some extents of a multi-level built-in
            array type.

	\details  This type-traits class (template) gives an option between removing
	          one extent (`std::remove_extent`) or all of them
	          (`std::remove_all_extents`).

	\tparam Array  The type to strip.
	\tparam Count  The number of extents to strip.
 */
template < typename Array, std::size_t Count >
struct remove_some_extents;


//  Array-extent stripping traits class template specializations  ------------//

//! Case with indefinite array but no extents to strip
template < typename T >
struct remove_some_extents< T[], 0u >
{ typedef T type[]; };

//! Case with definite array but no extents to strip
template < typename T, std::size_t N >
struct remove_some_extents< T[N], 0u >
{ typedef T type[N]; };

//! Case with indefinite array and extents to strip
template < typename T, std::size_t L >
struct remove_some_extents< T[], L >
{ typedef typename remove_some_extents<T, L - 1u>::type type; };

//! Case with definite array and extents to strip
template < typename T, std::size_t N, std::size_t L >
struct remove_some_extents< T[N], L >
{ typedef typename remove_some_extents<T, L - 1u>::type type; };

//! General case
template < typename A, std::size_t >
struct remove_some_extents
{ typedef A type; };


#endif // REMOVE_SOME_EXTENTS_HPP