Aras Pranckevicius
8fd2b79ca1
In preparation for a larger change (D14162), some BLI_bitmap functionality that could be submitted separately: - Ability to declare a fixed size bitmap by-value, without extra memory allocation: BLI_BITMAP_DECLARE - Function to find the index of lowest unset bit: BLI_bitmap_find_first_unset - Test coverage of the above. Reviewed By: Campbell Barton, Bastien Montagne Differential Revision: https://developer.blender.org/D15454
69 lines
1.7 KiB
C
69 lines
1.7 KiB
C
/* SPDX-License-Identifier: GPL-2.0-or-later
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* Copyright 2012 by Nicholas Bishop. All rights reserved. */
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/** \file
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* \ingroup bli
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*
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* Utility functions for variable size bit-masks.
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*/
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#include <limits.h>
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#include <string.h>
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#include "BLI_bitmap.h"
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#include "BLI_math_bits.h"
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#include "BLI_utildefines.h"
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void BLI_bitmap_set_all(BLI_bitmap *bitmap, bool set, size_t bits)
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{
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memset(bitmap, set ? UCHAR_MAX : 0, BLI_BITMAP_SIZE(bits));
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}
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void BLI_bitmap_flip_all(BLI_bitmap *bitmap, size_t bits)
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{
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size_t blocks_num = _BITMAP_NUM_BLOCKS(bits);
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for (size_t i = 0; i < blocks_num; i++) {
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bitmap[i] ^= ~(BLI_bitmap)0;
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}
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}
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void BLI_bitmap_copy_all(BLI_bitmap *dst, const BLI_bitmap *src, size_t bits)
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{
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memcpy(dst, src, BLI_BITMAP_SIZE(bits));
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}
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void BLI_bitmap_and_all(BLI_bitmap *dst, const BLI_bitmap *src, size_t bits)
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{
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size_t blocks_num = _BITMAP_NUM_BLOCKS(bits);
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for (size_t i = 0; i < blocks_num; i++) {
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dst[i] &= src[i];
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}
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}
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void BLI_bitmap_or_all(BLI_bitmap *dst, const BLI_bitmap *src, size_t bits)
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{
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size_t blocks_num = _BITMAP_NUM_BLOCKS(bits);
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for (size_t i = 0; i < blocks_num; i++) {
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dst[i] |= src[i];
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}
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}
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int BLI_bitmap_find_first_unset(const BLI_bitmap *bitmap, const size_t bits)
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{
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const size_t blocks_num = _BITMAP_NUM_BLOCKS(bits);
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int result = -1;
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/* Skip over completely set blocks. */
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int index = 0;
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while (index < blocks_num && bitmap[index] == ~0u) {
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index++;
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}
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if (index < blocks_num) {
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/* Found a partially used block: find the lowest unused bit. */
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const uint m = ~bitmap[index];
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BLI_assert(m != 0);
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const uint bit_index = bitscan_forward_uint(m);
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result = bit_index + (index << _BITMAP_POWER);
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}
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return result;
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}
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