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author | Campbell Barton <ideasman42@gmail.com> | 2017-09-19 13:21:52 +0300 |
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committer | Campbell Barton <ideasman42@gmail.com> | 2017-09-19 13:22:24 +0300 |
commit | 7b952432409a6d1f268699846cbbf6fc00c347c7 (patch) | |
tree | 686829804112024f85307b3724fd6c3d281d85e5 /source/blender/blenlib/BLI_utildefines_iter.h | |
parent | 60956397ca46ae31f5fc1931a8a7fc98d4f1b699 (diff) |
BLI_utildefines_iter: Use for iteration helpers
Diffstat (limited to 'source/blender/blenlib/BLI_utildefines_iter.h')
-rw-r--r-- | source/blender/blenlib/BLI_utildefines_iter.h | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/source/blender/blenlib/BLI_utildefines_iter.h b/source/blender/blenlib/BLI_utildefines_iter.h new file mode 100644 index 00000000000..094c1a4b3dc --- /dev/null +++ b/source/blender/blenlib/BLI_utildefines_iter.h @@ -0,0 +1,52 @@ +/* + * ***** BEGIN GPL LICENSE BLOCK ***** + * + * 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. + * + * ***** END GPL LICENSE BLOCK ***** + */ + +#ifndef __BLI_UTILDEFINES_ITER_H__ +#define __BLI_UTILDEFINES_ITER_H__ + +/** \file BLI_utildefines_iter.h + * \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__ */ |