Just checking if this was still on the radar, seems mostly comment and type
changes so maybe a relatively minor update?
If any help is needed to make the adjustments let me know and I can help.
Thanks,
Andrew
On Mon, Sep 2, 2024 at 11:14 AM Daniel Kiper <dki...@net-space.pl> wrote:
> On Sat, Aug 17, 2024 at 08:30:22PM +0300, Vladimir Serbinenko wrote:
> > Signed-off-by: Vladimir Serbinenko <phco...@gmail.com>
> > ---
> > grub-core/lib/datetime.c | 31 ++++++++++++++++++++++++-------
> > include/grub/datetime.h | 15 +++++++--------
> > 2 files changed, 31 insertions(+), 15 deletions(-)
> >
> > diff --git a/grub-core/lib/datetime.c b/grub-core/lib/datetime.c
> > index 9120128ca..e4bdc5c4f 100644
> > --- a/grub-core/lib/datetime.c
> > +++ b/grub-core/lib/datetime.c
> > @@ -59,6 +59,8 @@ grub_get_weekday_name (struct grub_datetime *datetime)
> > #define SECPERDAY (24*SECPERHOUR)
> > #define DAYSPERYEAR 365
> > #define DAYSPER4YEARS (4*DAYSPERYEAR+1)
> > +#define DAYSPER100YEARS (100*DAYSPERYEAR+24)
> > +#define DAYSPER400YEARS (400*DAYSPERYEAR+97)
> >
> >
> > void
> > @@ -71,7 +73,7 @@ grub_unixtime2datetime (grub_int64_t nix, struct
> grub_datetime *datetime)
> > /* Convenience: let's have 3 consecutive non-bissextile years
> > at the beginning of the counting date. So count from 1901. */
> > int days_epoch;
> > - /* Number of days since 1st Januar, 1901. */
> > + /* Number of days since 1st January, 1 (proleptic). */
> > unsigned days;
> > /* Seconds into current day. */
> > unsigned secs_in_day;
> > @@ -87,9 +89,25 @@ grub_unixtime2datetime (grub_int64_t nix, struct
> grub_datetime *datetime)
> > days_epoch = grub_divmod64 (nix, SECPERDAY, NULL);
> >
> > secs_in_day = nix - days_epoch * SECPERDAY;
> > - days = days_epoch + 69 * DAYSPERYEAR + 17;
> > + days = days_epoch + 369 * DAYSPERYEAR + 17 + 24 * 3 + 4 *
> DAYSPER400YEARS;
>
> I can imagine how this math was build but I would prefer if you add
> a comment where these numbers come from...
>
> > - datetime->year = 1901 + 4 * (days / DAYSPER4YEARS);
> > + datetime->year = 1 + 400 * (days / DAYSPER400YEARS);
> > + days %= DAYSPER400YEARS;
> > +
> > + /* On 31st December of bissextile years 365 days from the beginning
> > + of the year elapsed but year isn't finished yet */
>
> I think the comment is not precise. It happens once per 400 years.
> Right? I think it should be clarified.
>
> > + if (days / DAYSPER100YEARS == 4)
> > + {
> > + datetime->year += 396;
> > + days -= 396*DAYSPERYEAR + 96;
>
> Where do these numbers come from? The math begs for comment.
>
> > + }
> > + else
> > + {
> > + datetime->year += 100 * (days / DAYSPER100YEARS);
> > + days %= DAYSPER100YEARS;
>
> Ditto.
>
> > + }
> > +
> > + datetime->year += 4 * (days / DAYSPER4YEARS);
> > days %= DAYSPER4YEARS;
> > /* On 31st December of bissextile years 365 days from the beginning
> > of the year elapsed but year isn't finished yet */
> > @@ -103,11 +121,10 @@ grub_unixtime2datetime (grub_int64_t nix, struct
> grub_datetime *datetime)
> > datetime->year += days / DAYSPERYEAR;
> > days %= DAYSPERYEAR;
> > }
> > + int isbisextile = datetime->year % 4 == 0 && (datetime->year % 100 !=
> 0 || datetime->year % 400 == 0);
>
> Could you use bool instead? And define variable at the beginning of
> function?
>
> > for (i = 0; i < 12
> > - && days >= (i==1 && datetime->year % 4 == 0
> > - ? 29 : months[i]); i++)
> > - days -= (i==1 && datetime->year % 4 == 0
> > - ? 29 : months[i]);
> > + && days >= (i==1 && isbisextile ? 29 : months[i]); i++)
> > + days -= (i==1 && isbisextile ? 29 : months[i]);
> > datetime->month = i + 1;
> > datetime->day = 1 + days;
> > datetime->hour = (secs_in_day / SECPERHOUR);
> > diff --git a/include/grub/datetime.h b/include/grub/datetime.h
> > index bcec636f0..9289b0d00 100644
> > --- a/include/grub/datetime.h
> > +++ b/include/grub/datetime.h
> > @@ -54,7 +54,7 @@ void grub_unixtime2datetime (grub_int64_t nix,
> > static inline int
> > grub_datetime2unixtime (const struct grub_datetime *datetime,
> grub_int64_t *nix)
> > {
> > - grub_int32_t ret;
> > + grub_int64_t ret;
> > int y4, ay;
> > const grub_uint16_t monthssum[12]
> > = { 0,
> > @@ -75,15 +75,11 @@ grub_datetime2unixtime (const struct grub_datetime
> *datetime, grub_int64_t *nix)
> > const int SECPERHOUR = 60 * SECPERMIN;
> > const int SECPERDAY = 24 * SECPERHOUR;
> > const int SECPERYEAR = 365 * SECPERDAY;
> > - const int SECPER4YEARS = 4 * SECPERYEAR + SECPERDAY;
> > + const grub_int64_t SECPER4YEARS = 4 * SECPERYEAR + SECPERDAY;
> >
> > - if (datetime->year > 2038 || datetime->year < 1901)
> > - return 0;
> > if (datetime->month > 12 || datetime->month < 1)
> > return 0;
> >
> > - /* In the period of validity of unixtime all years divisible by 4
> > - are bissextile*/
> > /* Convenience: let's have 3 consecutive non-bissextile years
> > at the beginning of the epoch. So count from 1973 instead of 1970
> */
> > ret = 3 * SECPERYEAR + SECPERDAY;
> > @@ -94,13 +90,16 @@ grub_datetime2unixtime (const struct grub_datetime
> *datetime, grub_int64_t *nix)
> > ret += y4 * SECPER4YEARS;
> > ret += ay * SECPERYEAR;
> >
> > + ret -= ((datetime->year - 1) / 100 - (datetime->year - 1) / 400 - 15)
> * SECPERDAY;
>
> Again, please comment this math...
>
> > ret += monthssum[datetime->month - 1] * SECPERDAY;
> > - if (ay == 3 && datetime->month >= 3)
> > + int isbisextile = ay == 3 && (datetime->year % 100 != 0 ||
> datetime->year % 400 == 0);
>
> Ditto.
>
> And could you use bool instead of int?
>
> > + if (isbisextile && datetime->month >= 3)
> > ret += SECPERDAY;
> >
> > ret += (datetime->day - 1) * SECPERDAY;
> > if ((datetime->day > months[datetime->month - 1]
> > - && (!ay || datetime->month != 2 || datetime->day != 29))
> > + && !(isbisextile && datetime->month == 2 && datetime->day == 29))
>
> It would be nice to add a comment here too.
>
> Daniel
>
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