On 04/01/2013 11:42 PM, Osier Yang wrote:
--- src/libvirt_private.syms | 1 + src/util/virbitmap.c | 30 ++++++++++++++++++++++++++++++ src/util/virbitmap.h | 3 +++ 3 files changed, 34 insertions(+)
+bool virBitmapIsAllClear(virBitmapPtr bitmap) +{ + int i; + int unusedBits; + size_t sz; + + unusedBits = bitmap->map_len * VIR_BITMAP_BITS_PER_UNIT - bitmap->max_bit; + + sz = bitmap->map_len; + if (unusedBits > 0) + sz--; + + for (i = 0; i < sz; i++) + if (bitmap->map[i] != 0) + return false; + + if (unusedBits > 0) { + if ((bitmap->map[sz] & ((1UL << (VIR_BITMAP_BITS_PER_UNIT - unusedBits)) - 1))) + return false;
You are being careful to avoid assuming any state about the bits in the tail beyond the bitmap size. But I thought our code was already careful to ensure that the tail bits are always 0. Therefore, you should be able to just check that the entire bitmap->map is 0, without special-casing the tail. -- Eric Blake eblake redhat com +1-919-301-3266 Libvirt virtualization library http://libvirt.org