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

[David Hildenbrand]

On 11/10/2018 11:21, Dr. David Alan Gilbert wrote:
> * David Hildenbrand (address@hidden) wrote:
>> On 11/10/2018 11:08, Dr. David Alan Gilbert wrote:
>>> * David Hildenbrand (address@hidden) 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 <address@hidden>
>>>> ---
>>>>  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 address@hidden,@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 address@hidden,@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'.
> 

hmm "range_would_overflow()" ?

> Dave

-- 

Thanks,

David / dhildenb