Re: [Qemu-devel] [PATCH v1 4/7] range: add some more functions

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* David Hildenbrand (david@redhat.com) wrote:
> On 11/10/2018 11:08, Dr. David Alan Gilbert wrote:
> > * David Hildenbrand (david@redhat.com) wrote:
> >> Add some more functions that will be used in memory-device context.
> >>
> >> range_init(): Init using lower bound and size
> >> range_valid(): Check if there would be an overflow when initializin
> >> range_size(): Extract the size of a range
> >> range_overlaps_range(): Check for overlaps of two ranges
> >> range_contains_range(): Check if one range is contained in the other
> >> range_starts_before_range(): Check if one range starts before another
> >> range_ends_after_range(): Check if one range ends after another
> >>
> >> Signed-off-by: David Hildenbrand <david@redhat.com>
> >> ---
> >>  include/qemu/range.h | 80 ++++++++++++++++++++++++++++++++++++++++++++
> >>  1 file changed, 80 insertions(+)
> >>
> >> diff --git a/include/qemu/range.h b/include/qemu/range.h
> >> index 7e75f4e655..18e8acf22f 100644
> >> --- a/include/qemu/range.h
> >> +++ b/include/qemu/range.h
> >> @@ -112,6 +112,86 @@ static inline uint64_t range_upb(Range *range)
> >>      return range->upb;
> >>  }
> >>  
> >> +/*
> >> + * Initialize @range to span the interval [@lob,@lob + @size - 1].
> >> + * @size may be 0.
> >> + */
> >> +static inline void range_init(Range *range, uint64_t lob, uint64_t size)
> >> +{
> >> +    range->lob = lob;
> >> +    range->upb = lob + size - 1;
> >> +    range_invariant(range);
> >> +}
> >> +
> >> +/*
> >> + * Check if the interval [@lob,@lob + @size - 1] would be valid or not
> >> + * (result in an overflow).
> >> + */
> >> +static inline bool range_valid(uint64_t lob, uint64_t size)
> >> +{
> >> +    return lob + size >= lob;
> >> +}
> > 
> > That name confused me, I'd expected that to have taken a range and check
> > it for something (like a non-asserting version of the invariant).
> 
> Then we have to remove all the variant asserts from the initializer
> functions (well, because then it is no longer an invariant then). Other
> ideas?

My worry here is just the name 'range_valid'.

Dave

> -- 
> 
> Thanks,
> 
> David / dhildenb
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK