gplib/include/gp/algorithm/rotate.hpp

#pragma once
#include "gp/algorithm/move.hpp"

namespace gp {
	template<typename iterator>
	iterator rotate(iterator first, iterator new_first, iterator last)
	{

		if(first == new_first) return last;
		if(new_first == last) return first;
		
		iterator in = new_first;
		iterator out = first;
		iterator mv = first;
		
		while(in != last) {
			if(out == mv) mv = in;
			gp::swap((*out++), (*in++));
		}
		
		// rotate the remaining sequence into place
		(rotate)(out, mv, last);
		return out;
	}

}