Re: [Qemu-devel] [PATCH 3/6] range: add min/max operations on ranges

[Igor Mammedov]

On Wed, 4 Sep 2013 13:48:35 +0300
"Michael S. Tsirkin" <address@hidden> wrote:

> Signed-off-by: Michael S. Tsirkin <address@hidden>
> ---
>  include/qemu/range.h | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/include/qemu/range.h b/include/qemu/range.h
> index 4a0780d..1c688ca 100644
> --- a/include/qemu/range.h
> +++ b/include/qemu/range.h
> @@ -17,6 +17,23 @@ struct Range {
>      uint64_t end;   /* 1 + the last byte. 0 if range empty or ends at 
> ~0x0LL. */
>  };
>  
> +static inline void range_extend(Range *range, Range *extend_by)
doc comment what it does pls.

> +{
> +    if (!extend_by->begin && !extend_by->end) {
> +        return;
> +    }
> +    if (!range->begin && !range->end) {
> +        *range = *extend_by;
> +        return;
> +    }
> +    if (range->begin > extend_by->begin) {
> +        range->begin = extend_by->begin;
> +    }
> +    if (range->end - 1 < extend_by->end - 1) {
(foo)->end could be 0 at this point leading to overflow when subtracted,
is it intended to be so?

> +        range->end = extend_by->end;
> +    }
> +}
> +
>  /* Get last byte of a range from offset + length.
>   * Undefined for ranges that wrap around 0. */
>  static inline uint64_t range_get_last(uint64_t offset, uint64_t len)