[Libguestfs] [PATCH v2 3/4] common: Add isaligned helper module

[Eric Blake]

On 08/03/2018 02:28 PM, Nir Soffer wrote:
> is_aligned (size, align) returns true if size is aligned to align,
> assuming that align is power of 2.
> 
> Suggested by Eric in
> https://www.redhat.com/archives/libguestfs/2018-August/msg00036.html
> ---
>   common/include/isaligned.h | 50 ++++++++++++++++++++++++++++++++++++++
>   1 file changed, 50 insertions(+)
>   create mode 100644 common/include/isaligned.h
> 

> +/* Return true if size is a multiple of align. align must be power of 2.
> + *
> + * Suggested by Eric Blake.  See:
> + * https://www.redhat.com/archives/libguestfs/2018-August/msg00036.html

Do we need this comment in the code? I'm fine if it is just in the 
commit message.

> + */
> +static inline bool
> +is_aligned (unsigned int size, unsigned int align)
> +{
> +  return !(size & (align - 1));
> +}

Should we assert() that align is indeed a power of 2, to make it harder 
for callers to misuse this function?  Otherwise, looks okay to me.


-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3266
Virtualization:  qemu.org | libvirt.org