Switching to [KMGTPE]i prefixes?

[Alexander Best]

On Fri Mar 25 11, Xin LI wrote:
> FYI I have a patch and I have incorporated some of Alexander's idea.
> 
> Difference:
> 
>  - Use of both HN_DIVISOR_1000 and HN_IEC_PREFIXES triggers an
> assertion.  I think it doesn't make sense to return since this is an
> API violation and we should just tell the caller explicitly;

actually i vote for removing all asserts in humanize_number.c and return -1
based upon the later checks.

the existing

assert(buf != NULL);
assert(suffix != NULL);

checks aren't really needed, since buf and suffix are also checked later on. so
just having:

        if (scale <= 0 || (scale >= maxscale &&
            (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0))
                return (-1);
                
        if (buf == NULL || suffix == NULL)
                return (-1);

        if ((flags & (HN_DIVISOR_1000 | HN_IEC_PREFIXES)) == 0)
                return (-1);

...should be enough.

>  - DIVISOR_1000 and !1000 cases use just same prefixes, so merge them
> while keeping divisor intact;

good idea. however i think you should add a comment to point out that the
default behavior is !DIVISOR_1000 && !HN_IEC_PREFIXES. one has to look very
closely to find out.

>  - Make prefixes table consistently long.  I have no strong opinion on
> this one, though, it's just what my original version used and I can
> change it to the way Alexander did if there is an advantage of doing
> that way.

i think the way you're doing it is nicer than how i implemented it.

> 
> (Note, it seems that we use HN_ prefix for both 'scale' and 'flags', I
> have sorted them by value but HN_IEC_PREFIXES should really belong to
> the flags group).

this is odd indeed. actually the possible 'scale' and 'flags' flags should
not have the same prefixes. but it appears we're stuck with this.

i think sorting me should sort them into the two groups and not value wise.
so it's

#define HN_DECIMAL              0x01
#define HN_NOSPACE              0x02
#define HN_B                    0x04
#define HN_DIVISOR_1000         0x08
#define HN_IEC_PREFIXES         0x40

#define HN_GETSCALE             0x10
#define HN_AUTOSCALE            0x20

> 
> Cheers,
> -- 
> Xin LI <delphij at delphij.net> http://www.delphij.net



-- 
a13x