diff options
| author | Wei Wang <wei.w.wang@intel.com> | 2018-12-11 16:24:48 +0800 |
|---|---|---|
| committer | Dr. David Alan Gilbert <dgilbert@redhat.com> | 2019-03-06 10:49:17 +0000 |
| commit | 94960256ae0bc346de49e2ef3808778e8468caf5 (patch) | |
| tree | 7c0c76eee320731fe0b811300185c96767e020fe | |
| parent | e7c91368d24637f077b457187f8dff4767dfadae (diff) | |
bitmap: bitmap_count_one_with_offset
Count the number of 1s in a bitmap starting from an offset.
Signed-off-by: Wei Wang <wei.w.wang@intel.com>
CC: Dr. David Alan Gilbert <dgilbert@redhat.com>
CC: Juan Quintela <quintela@redhat.com>
CC: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <1544516693-5395-3-git-send-email-wei.w.wang@intel.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
| -rw-r--r-- | include/qemu/bitmap.h | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/include/qemu/bitmap.h b/include/qemu/bitmap.h index 679f1bdce4..5c313346b9 100644 --- a/include/qemu/bitmap.h +++ b/include/qemu/bitmap.h @@ -232,6 +232,19 @@ static inline long bitmap_count_one(const unsigned long *bitmap, long nbits) } } +static inline long bitmap_count_one_with_offset(const unsigned long *bitmap, + long offset, long nbits) +{ + long aligned_offset = QEMU_ALIGN_DOWN(offset, BITS_PER_LONG); + long redundant_bits = offset - aligned_offset; + long bits_to_count = nbits + redundant_bits; + const unsigned long *bitmap_start = bitmap + + aligned_offset / BITS_PER_LONG; + + return bitmap_count_one(bitmap_start, bits_to_count) - + bitmap_count_one(bitmap_start, redundant_bits); +} + void bitmap_set(unsigned long *map, long i, long len); void bitmap_set_atomic(unsigned long *map, long i, long len); void bitmap_clear(unsigned long *map, long start, long nr); |