Re: [PATCH v3 2/2] date.c: allow compact version of ISO-8601 datetime

[Danh Doan <congdanhqx@gmail.com>]

On 2020-04-22 10:17:35-0700, Junio C Hamano <gitster@pobox.com> wrote:
> Đoàn Trần Công Danh  <congdanhqx@gmail.com> writes:
> 
> > Signed-off-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
> > ---
> >  date.c          | 22 ++++++++++++++++++++++
> >  t/t0006-date.sh |  3 +++
> >  2 files changed, 25 insertions(+)
> >
> > diff --git a/date.c b/date.c
> > index 62f23b4702..882242c2db 100644
> > --- a/date.c
> > +++ b/date.c
> > @@ -672,6 +672,28 @@ static int match_digit(const char *date, struct tm *tm, int *offset, int *tm_gmt
> >  		n++;
> >  	} while (isdigit(date[n]));
> >  
> > +	/* 8 digits, compact style of ISO-8601's date: YYYYmmDD */
> > +	/* 6 digits, compact style of ISO-8601's time: HHMMSS */
> > +	if (n == 8 || n == 6) {
> > +		unsigned int num1 = num / 10000;
> > +		unsigned int num2 = (num % 10000) / 100;
> > +		unsigned int num3 = num % 100;
> > +		if (n == 8 && num1 > 1900 &&
> > +		    num2 > 0 && num2 <= 12 &&
> > +		    num3 > 0  && num3 <= 31) {
> > +			tm->tm_year = num1 - 1900;
> > +			tm->tm_mon  = num2 - 1;
> > +			tm->tm_mday = num3;
> > +		} else if (n == 6 && num1 < 60 && num2 < 60 && num3 <= 60) {
> > +			tm->tm_hour = num1;
> > +			tm->tm_min  = num2;
> > +			tm->tm_sec  = num3;
> > +			if (*end == '.' && isdigit(end[1]))
> > +				strtoul(end + 1, &end, 10);
> > +		}
> > +		return end - date;
> > +	}
> > +
> 
> Looks sensible except that on our planet, one day has only 24 hours
> ;-).

My bad, I admit that I wouldn't run into this error if we have the
helper is_hms (or is_time)

> 
> I think we should try to reuse existing helpers as much as possible
> in date.c to avoid such stupid errors.  During my review of [1/2] I
> found is_date() would be a good thing to try reusing and also

I'll look into this and see which value should be passed to is_date

> extracted is_hms() as another candidate we could reuse.

-- 
Danh