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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /fs/xfs/libxfs/xfs_bit.c | |
parent | Initial commit. (diff) | |
download | linux-upstream.tar.xz linux-upstream.zip |
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/xfs/libxfs/xfs_bit.c')
-rw-r--r-- | fs/xfs/libxfs/xfs_bit.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/fs/xfs/libxfs/xfs_bit.c b/fs/xfs/libxfs/xfs_bit.c new file mode 100644 index 000000000..40ce5f309 --- /dev/null +++ b/fs/xfs/libxfs/xfs_bit.c @@ -0,0 +1,106 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2000-2005 Silicon Graphics, Inc. + * All Rights Reserved. + */ +#include "xfs.h" +#include "xfs_log_format.h" +#include "xfs_bit.h" + +/* + * XFS bit manipulation routines, used in non-realtime code. + */ + +/* + * Return whether bitmap is empty. + * Size is number of words in the bitmap, which is padded to word boundary + * Returns 1 for empty, 0 for non-empty. + */ +int +xfs_bitmap_empty(uint *map, uint size) +{ + uint i; + + for (i = 0; i < size; i++) { + if (map[i] != 0) + return 0; + } + + return 1; +} + +/* + * Count the number of contiguous bits set in the bitmap starting with bit + * start_bit. Size is the size of the bitmap in words. + */ +int +xfs_contig_bits(uint *map, uint size, uint start_bit) +{ + uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT); + uint result = 0; + uint tmp; + + size <<= BIT_TO_WORD_SHIFT; + + ASSERT(start_bit < size); + size -= start_bit & ~(NBWORD - 1); + start_bit &= (NBWORD - 1); + if (start_bit) { + tmp = *p++; + /* set to one first offset bits prior to start */ + tmp |= (~0U >> (NBWORD-start_bit)); + if (tmp != ~0U) + goto found; + result += NBWORD; + size -= NBWORD; + } + while (size) { + if ((tmp = *p++) != ~0U) + goto found; + result += NBWORD; + size -= NBWORD; + } + return result - start_bit; +found: + return result + ffz(tmp) - start_bit; +} + +/* + * This takes the bit number to start looking from and + * returns the next set bit from there. It returns -1 + * if there are no more bits set or the start bit is + * beyond the end of the bitmap. + * + * Size is the number of words, not bytes, in the bitmap. + */ +int xfs_next_bit(uint *map, uint size, uint start_bit) +{ + uint * p = ((unsigned int *) map) + (start_bit >> BIT_TO_WORD_SHIFT); + uint result = start_bit & ~(NBWORD - 1); + uint tmp; + + size <<= BIT_TO_WORD_SHIFT; + + if (start_bit >= size) + return -1; + size -= result; + start_bit &= (NBWORD - 1); + if (start_bit) { + tmp = *p++; + /* set to zero first offset bits prior to start */ + tmp &= (~0U << start_bit); + if (tmp != 0U) + goto found; + result += NBWORD; + size -= NBWORD; + } + while (size) { + if ((tmp = *p++) != 0U) + goto found; + result += NBWORD; + size -= NBWORD; + } + return -1; +found: + return result + ffs(tmp) - 1; +} |