/*
 * (C) Copyright 1996- ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 * In applying this licence, ECMWF does not waive the privileges and immunities
 * granted to it by virtue of its status as an intergovernmental organisation nor
 * does it submit to any jurisdiction.
 */


#include "eckit/utils/HyperCube.h"

//-----------------------------------------------------------------------------

namespace eckit {

//-----------------------------------------------------------------------------

static void addLoop(
	Ordinal      d,
	Ordinal      which,
	Ordinal      where,
	Ordinal      count,
	Ordinal      depth,
	HyperCube&   target,
	const HyperCube::Dimensions&  dims,
	HyperCube::Coordinates& coord,
	HyperCube::Remapping&   remap)
{
	if(d == depth)
		remap.push_back(target.index(coord));
	else {

		int k = 0;
		for( size_t i = 0; i < dims[d]; i++,k++)
		{
			if(which == d && i == where) k += count;
			coord[d]   = k;
			addLoop(d+1,which,where,count,depth,target,dims,coord,remap);
		}
	}
}

HyperCube HyperCube::addToDimension(Ordinal which,
	Ordinal where,Ordinal howMuch,Remapping& remap) const
{

	remap.clear();
	remap.reserve(count());

	Dimensions  newdims = dimensions_;
	Coordinates coord(dimensions_.size());


	newdims[which] += howMuch;

	HyperCube target(newdims);

	addLoop(0,which,where,howMuch,dimensions_.size(),target,dimensions_,coord,remap);

	return target;
}

void HyperCube::coordinates(Ordinal index,Coordinates& result) const
{
	ASSERT(result.size() == dimensions_.size());

	for(int i = dimensions_.size()-1; i >= 0; i--)
	{
		result[i] = (index % dimensions_[i]);
		index    /= dimensions_[i];
	}

	ASSERT(index == 0);
}

//-----------------------------------------------------------------------------

} // namespace eckit
