/*
  Copyright (C) 2018 David Robillard <d@drobilla.net>
  Copyright (C) 2006-2007 Chris Hamilton <chamilton@cs.dal.ca>

  This program is free software: you can redistribute it and/or modify it under
  the terms of the GNU General Public License as published by the Free Software
  Foundation, either version 2 of the License, or (at your option) any later
  version.

  This program is distributed in the hope that it will be useful, but WITHOUT
  ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
  details.

  You should have received a copy of the GNU General Public License along with
  this program.  If not, see <https://www.gnu.org/licenses/>.
*/

#ifndef CHILBERT_BITVECINDEX_HPP
#define CHILBERT_BITVECINDEX_HPP

#include <cassert>
#include <climits>
#include <cstddef>

namespace chilbert {

/// Index into a multi-rack bit vector
template <class BitVec>
struct BitVecIndex
{
	using Rack = typename BitVec::Rack;

	static constexpr size_t bits_per_rack = sizeof(Rack) * CHAR_BIT;

	BitVecIndex(const size_t bits)
	  : rack{bits / bits_per_rack}
	  , bit{bits - rack * bits_per_rack}
	{
		assert(bit < bits_per_rack);
	}

	size_t rack;
	size_t bit;
};

} // namespace chilbert

#endif