bitmap: introduce bitmap_count_one()

Count how many bits set in the bitmap.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/util/bitmap.c b/util/bitmap.c
index efced9a7d8..90a42ff625 100644
--- a/util/bitmap.c
+++ b/util/bitmap.c
@@ -355,3 +355,18 @@ int slow_bitmap_intersects(const unsigned long *bitmap1,
     }
     return 0;
 }
+
+long slow_bitmap_count_one(const unsigned long *bitmap, long nbits)
+{
+    long k, lim = nbits / BITS_PER_LONG, result = 0;
+
+    for (k = 0; k < lim; k++) {
+        result += ctpopl(bitmap[k]);
+    }
+
+    if (nbits % BITS_PER_LONG) {
+        result += ctpopl(bitmap[k] & BITMAP_LAST_WORD_MASK(nbits));
+    }
+
+    return result;
+}