Add angle TZ angle bracket support to tzset_r
- from Brian Inglis <Brian.Inglis@systematicsw.ab.ca>
- add support to _tzset_unlocked_r() to support quoting std and dst
names with angle brackets <> as per Posix
- modify documentation of tzset.c
This commit is contained in:
Jeff Johnston
parent
2c157e7e23
commit
539ac66ffa
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@ -1,6 +1,6 @@
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/*
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FUNCTION
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<<tzset>>---set timezone characteristics from TZ environment variable
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<<tzset>>---set timezone characteristics from <[TZ]> environment variable
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INDEX
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tzset
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@ -13,36 +13,84 @@ SYNOPSIS
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void _tzset_r (struct _reent *<[reent_ptr]>);
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DESCRIPTION
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<<tzset>> examines the TZ environment variable and sets up the three
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external variables: <<_timezone>>, <<_daylight>>, and <<tzname>>. The
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value of <<_timezone>> shall be the offset from the current time zone
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to GMT. The value of <<_daylight>> shall be 0 if there is no daylight
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savings time for the current time zone, otherwise it will be non-zero.
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The <<tzname>> array has two entries: the first is the name of the
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standard time zone, the second is the name of the daylight-savings time
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zone.
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<<tzset>> examines the <[TZ]> environment variable and sets up the three
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external variables: <<_timezone>>, <<_daylight>>, and <<tzname>>.
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The value of <<_timezone>> shall be the offset from the current time
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to Universal Time.
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The value of <<_daylight>> shall be 0 if there is no daylight savings
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time for the current time zone, otherwise it will be non-zero.
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The <<tzname>> array has two entries: the first is the designation of the
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standard time period, the second is the designation of the alternate time
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period.
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The TZ environment variable is expected to be in the following POSIX
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format:
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The <[TZ]> environment variable is expected to be in the following POSIX
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format (spaces inserted for clarity):
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stdoffset1[dst[offset2][,start[/time1],end[/time2]]]
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<[std]> <[offset1]> [<[dst]> [<[offset2]>] [,<[start]> [/<[time1]>], <[end]> [/<[time2]>]]]
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where: std is the name of the standard time-zone (minimum 3 chars)
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offset1 is the value to add to local time to arrive at Universal time
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it has the form: hh[:mm[:ss]]
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dst is the name of the alternate (daylight-savings) time-zone (min 3 chars)
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offset2 is the value to add to local time to arrive at Universal time
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it has the same format as the std offset
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start is the day that the alternate time-zone starts
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time1 is the optional time that the alternate time-zone starts
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(this is in local time and defaults to 02:00:00 if not specified)
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end is the day that the alternate time-zone ends
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time2 is the time that the alternate time-zone ends
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(it is in local time and defaults to 02:00:00 if not specified)
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where:
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Note that there is no white-space padding between fields. Also note that
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if TZ is null, the default is Universal GMT which has no daylight-savings
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time. If TZ is empty, the default EST5EDT is used.
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<[std]> is the designation for the standard time period (minimum 3,
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maximum <<TZNAME_MAX>> bytes) in one of two forms:
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*- quoted within angle bracket '<' '>' characters: portable numeric
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sign or alphanumeric characters in the current locale; the
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quoting characters are not included in the designation
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*- unquoted: portable alphabetic characters in the current locale
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<[offset1]> is the value to add to local standard time to get Universal Time;
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it has the format:
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[<[S]>]<[hh]>[:<[mm]>[:<[ss]>]]
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where:
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<[S]> is an optional numeric sign character; if negative '-', the
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time zone is East of the International Reference
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Meridian; else it is positive and West, and '+' may be used
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<[hh]> is the required numeric hour between 0 and 24
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<[mm]> is the optional numeric minute between 0 and 59
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<[ss]> is the optional numeric second between 0 and 59
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<[dst]> is the designation of the alternate (daylight saving or
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summer) time period, with the same limits and forms as
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the standard time period designation
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<[offset2]> is the value to add to local alternate time to get
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Universal Time; it has the same format as <[offset1]>
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<[start]> is the date in the year that alternate time starts;
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the form may be one of:
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(quotes "'" around characters below are used only to distinguish literals)
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<[n]> zero based Julian day (0-365), counting February 29 Leap days
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'J'<[n]> one based Julian day (1-365), not counting February 29 Leap
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days; in all years day 59 is February 28 and day 60 is March 1
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'M'<[m]>'.'<[w]>'.'<[d]>
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month <[m]> (1-12) week <[w]> (1-5) day <[d]> (0-6) where week 1 is
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the first week in month <[m]> with day <[d]>; week 5 is the last
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week in the month; day 0 is Sunday
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<[time1]> is the optional local time that alternate time starts, in
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the same format as <[offset1]> without any sign, and defaults
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to 02:00:00
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<[end]> is the date in the year that alternate time ends, in the same
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forms as <[start]>
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<[time2]> is the optional local time that alternate time ends, in
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the same format as <[offset1]> without any sign, and
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defaults to 02:00:00
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Note that there is no white-space padding between fields. Also note that
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if <[TZ]> is null, the default is Universal Time which has no daylight saving
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time. If <[TZ]> is empty, the default EST5EDT is used.
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The function <<_tzset_r>> is identical to <<tzset>> only it is reentrant
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and is used for applications that use multiple threads.
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@ -9,8 +9,11 @@
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#define sscanf siscanf /* avoid to pull in FP functions. */
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static char __tzname_std[11];
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static char __tzname_dst[11];
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#define TZNAME_MIN 3 /* POSIX min TZ abbr size local def */
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#define TZNAME_MAX 10 /* POSIX max TZ abbr size local def */
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static char __tzname_std[TZNAME_MAX + 1];
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static char __tzname_dst[TZNAME_MAX + 1];
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static char *prev_tzenv = NULL;
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void
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@ -45,8 +48,25 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
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if (*tzenv == ':')
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++tzenv;
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if (sscanf (tzenv, "%10[^0-9,+-]%n", __tzname_std, &n) <= 0)
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return;
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/* allow POSIX angle bracket < > quoted signed alphanumeric tz abbr e.g. <MESZ+0330> */
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if (*tzenv == '<')
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{
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++tzenv;
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/* quit if no items, too few or too many chars, or no close quote '>' */
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if (sscanf (tzenv, "%10[-+0-9A-Za-z]%n", __tzname_std, &n) <= 0
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|| n < TZNAME_MIN || TZNAME_MAX < n || '>' != tzenv[n])
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return;
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++tzenv; /* bump for close quote '>' */
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}
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else
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{
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/* allow POSIX unquoted alphabetic tz abbr e.g. MESZ */
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if (sscanf (tzenv, "%10[A-Za-z]%n", __tzname_std, &n) <= 0
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|| n < TZNAME_MIN || TZNAME_MAX < n)
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return;
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}
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tzenv += n;
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@ -69,16 +89,37 @@ _tzset_unlocked_r (struct _reent *reent_ptr)
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_tzname[0] = __tzname_std;
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tzenv += n;
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if (sscanf (tzenv, "%10[^0-9,+-]%n", __tzname_dst, &n) <= 0)
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{ /* No dst */
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_tzname[1] = _tzname[0];
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_timezone = tz->__tzrule[0].offset;
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_daylight = 0;
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return;
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/* allow POSIX angle bracket < > quoted signed alphanumeric tz abbr e.g. <MESZ+0330> */
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if (*tzenv == '<')
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{
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++tzenv;
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/* quit if no items, too few or too many chars, or no close quote '>' */
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if (sscanf (tzenv, "%10[-+0-9A-Za-z]%n", __tzname_dst, &n) <= 0
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|| n < TZNAME_MIN || TZNAME_MAX < n || '>' != tzenv[n])
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{ /* No dst */
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_tzname[1] = _tzname[0];
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_timezone = tz->__tzrule[0].offset;
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_daylight = 0;
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return;
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}
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++tzenv; /* bump for close quote '>' */
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}
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else
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_tzname[1] = __tzname_dst;
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{
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/* allow POSIX unquoted alphabetic tz abbr e.g. MESZ */
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if (sscanf (tzenv, "%10[A-Za-z]%n", __tzname_dst, &n) <= 0
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|| n < TZNAME_MIN || TZNAME_MAX < n)
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{ /* No dst */
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_tzname[1] = _tzname[0];
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_timezone = tz->__tzrule[0].offset;
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_daylight = 0;
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return;
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}
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}
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_tzname[1] = __tzname_dst;
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tzenv += n;
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/* otherwise we have a dst name, look for the offset */
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