From 94960256ae0bc346de49e2ef3808778e8468caf5 Mon Sep 17 00:00:00 2001 From: Wei Wang Date: Tue, 11 Dec 2018 16:24:48 +0800 Subject: bitmap: bitmap_count_one_with_offset Count the number of 1s in a bitmap starting from an offset. Signed-off-by: Wei Wang CC: Dr. David Alan Gilbert CC: Juan Quintela CC: Michael S. Tsirkin Reviewed-by: Dr. David Alan Gilbert Message-Id: <1544516693-5395-3-git-send-email-wei.w.wang@intel.com> Signed-off-by: Dr. David Alan Gilbert --- include/qemu/bitmap.h | 13 +++++++++++++ 1 file changed, 13 insertions(+) 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); -- cgit v1.2.3