[PATCH] Add support for TZ names with <> in tzset
Corinna Vinschen
vinschen@redhat.com
Mon Nov 16 15:13:59 GMT 2020
Hi Earle,
On Nov 14 15:03, Earle F. Philhower, III via Newlib wrote:
> Howdy all,
>
> Attached is a patch which extends the tzset() function to support a format
> for "unnamed" TZ environment timezones which use "<+/-nn>" as the timezone
> name instead of an alphabetic name. These are supported in glibc and are
> present in several major TZ databases that we use on the ESP8266 Arduino
> core. For example,
>
> > #define TZ_Africa_Casablanca "<+01>-1"
>
> The existing tzset sscanf format string breaks at the first "+", assuming
> it's the
> beginning of the offset. This patch special-cases names beginning with "<"
> to
> circumvent the issue.
>
> Signed-off-by: Earle F. Philhower, III <earlephilhower@yahoo.com>
Basically this looks ok. I have two nits, though.
- Now that the scanning got more complicated than a single sscanf call,
this crys out for a helper function doing the actual scanning for
both, std and dst strings. This could be an inline function which is
only inlined
#if !defined(PREFER_SIZE_OVER_SPEED) && !defined(__OPTIMIZE_SIZE__)
- The strcat call seems a bit heavy. What about sth like this instead:
__tzname_ptr[n - 1] = '>';
__tzname_ptr[n] = '\0';
Thanks,
Corinna
> ---
> newlib/libc/time/tzset_r.c | 46 ++++++++++++++++++++++++++++++--------
> 1 file changed, 37 insertions(+), 9 deletions(-)
>
> diff --git a/newlib/libc/time/tzset_r.c b/newlib/libc/time/tzset_r.c
> index 9e0cf834b..5b8b692ee 100644
> --- a/newlib/libc/time/tzset_r.c
> +++ b/newlib/libc/time/tzset_r.c
> @@ -45,8 +45,19 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
> if (*tzenv == ':')
> ++tzenv;
>
> - if (sscanf (tzenv, "%10[^0-9,+-]%n", __tzname_std, &n) <= 0)
> - return;
> + if (tzenv[0] == '<')
> + {
> + /* This is of the form "<[+-]nn>" so needs a different parsing */
> + if (sscanf (tzenv, "%9[^>]>%n", __tzname_std, &n) <= 0)
> + return;
> + /* Include the final > */
> + strcat (__tzname_std, ">");
> + }
> + else
> + {
> + if (sscanf (tzenv, "%10[^0-9,+-]%n", __tzname_std, &n) <= 0)
> + return;
> + }
>
> tzenv += n;
>
> @@ -69,15 +80,32 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
> _tzname[0] = __tzname_std;
> tzenv += n;
>
> - if (sscanf (tzenv, "%10[^0-9,+-]%n", __tzname_dst, &n) <= 0)
> - { /* No dst */
> - _tzname[1] = _tzname[0];
> - _timezone = tz->__tzrule[0].offset;
> - _daylight = 0;
> - return;
> + if (tzenv[0] == '<')
> + {
> + /* This is of the form "<[+-]nn>" so needs a different parsing */
> + if (sscanf (tzenv, "%9[^>]>%n", __tzname_dst, &n) <= 0)
> + { /* No dst */
> + _tzname[1] = _tzname[0];
> + _timezone = tz->__tzrule[0].offset;
> + _daylight = 0;
> + return;
> + }
> + /* Include the final > */
> + strcat (__tzname_dst, ">");
> + _tzname[1] = __tzname_dst;
> }
> else
> - _tzname[1] = __tzname_dst;
> + {
> + if (sscanf (tzenv, "%10[^0-9,+-]%n", __tzname_dst, &n) <= 0)
> + { /* No dst */
> + _tzname[1] = _tzname[0];
> + _timezone = tz->__tzrule[0].offset;
> + _daylight = 0;
> + return;
> + }
> + else
> + _tzname[1] = __tzname_dst;
> + }
>
> tzenv += n;
>
> --
> 2.17.1
>
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