/*
 * 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 */

#ifndef __BLI_UTILDEFINES_ITER_H__
#define __BLI_UTILDEFINES_ITER_H__

/** \file
 * \ingroup bli
 *
 * General looping helpers, use `BLI_FOREACH` prefix.
 */

/**
 * Even value distribution.
 *
 * \a src must be larger than \a dst,
 * \a dst defines the number of iterations, their values are evenly spaced.
 *
 * The following pairs represent (src, dst) arguments and the values they loop over.
 * <pre>
 * (19, 4) ->    [2, 7, 11. 16]
 * (100, 5) ->   [9, 29, 49, 69, 89]
 * (100, 3) ->   [16, 49, 83]
 * (100, 100) -> [0..99]
 * </pre>
 * \note this is mainly useful for numbers that might not divide evenly into eachother.
 */
#define BLI_FOREACH_SPARSE_RANGE(src, dst, i) \
  for (int _src = (src), _src2 = _src * 2, _dst2 = (dst)*2, _error = _dst2 - _src, i = 0, _delta; \
       ((void)(_delta = divide_floor_i(_error, _dst2)), (void)(i -= _delta), (i < _src)); \
       _error -= (_delta * _dst2) + _src2)

#endif /* __BLI_UTILDEFINES_ITER_H__ */
