Merged in better support of ISO 8601 from elsie.nci.nih.gov.
Added the conversion specifiers %g and %G, that are replaced by the year which contains the greater part of the week in question.
This commit is contained in:
Wolfgang Helbig
parent
ab215c6703
commit
b9b51fb731
lib/libc/stdtime
@ -35,7 +35,7 @@
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.\"
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.\" @(#)strftime.3 8.1 (Berkeley) 6/4/93
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.\"
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.Dd June 4, 1993
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.Dd October 4, 1997
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.Dt STRFTIME 3
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.Os
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.Sh NAME
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@ -113,6 +113,14 @@ representations.
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.It Cm %e
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is replaced by the day of month as a decimal number (1-31); single
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digits are preceded by a blank.
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.It Cm \&%G
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is replaced by a year as a decimal number with century.
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This year is the one that contains the greater part of
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the week (Monday as the first day of the week).
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.It Cm %g
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is replaced by the same year as in
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.Dq Li %G ,
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but as a decimal number without century (00-99).
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.It Cm \&%H
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is replaced by the hour (24-hour clock) as a decimal number (00-23).
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.It Cm %h
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@ -164,9 +172,10 @@ the week) as a decimal number (00-53).
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is replaced by the weekday (Monday as the first day of the week)
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as a decimal number (1-7).
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.It Cm \&%V
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is replaced by the week number of the year (the first
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Monday as the first day of week 1) as a
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decimal number (01-53).
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is replaced by the week number of the year (Monday as the first day of
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the week) as a decimal number (01-53). If the week containing January
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1 has four or more days in the new year, then it is week 1; otherwise
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it is the last week of the previous year, and the next week is week 1.
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.It Cm %v
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is equivalent to
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.Dq Li %e-%b-%Y .
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@ -205,9 +214,34 @@ The
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.Fn strftime
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function
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conforms to
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.St -ansiC .
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The
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.Ql %s
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conversion specification is an extension.
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.St -ansiC
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with a lot of extensions including
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.Ql %C ,
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.Ql %D ,
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.Ql %E* ,
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.Ql %e ,
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.Ql %G ,
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.Ql %g ,
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.Ql %h ,
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.Ql %k ,
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.Ql %l ,
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.Ql %n ,
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.Ql %O* ,
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.Ql \&%R ,
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.Ql %r ,
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.Ql %s ,
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.Ql \&%T ,
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.Ql %t ,
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.Ql %u ,
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.Ql \&%V ,
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.Ql %+ .
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The peculiar week number and year occuring in the replacements of
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.Ql %G ,
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.Ql %g
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and
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.Ql \&%V
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are defined in ISO 8601: 1988.
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.Sh BUGS
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There is no conversion specification for the phase of the moon.
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@ -17,7 +17,7 @@
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#ifdef LIBC_RCS
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static const char rcsid[] =
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"$Id: strftime.c,v 1.17 1997/02/22 15:03:19 peter Exp $";
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"$Id: strftime.c,v 1.18 1997/08/09 15:43:53 joerg Exp $";
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#endif
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#ifndef lint
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@ -234,67 +234,89 @@ label:
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pt = _conv((t->tm_wday == 0) ? 7 : t->tm_wday,
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"%d", pt, ptlim);
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continue;
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case 'V':
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/*
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** From Arnold Robbins' strftime version 3.0:
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** "the week number of the year (the first
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** Monday as the first day of week 1) as a
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** decimal number (01-53). The method for
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** determining the week number is as specified
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** by ISO 8601 (to wit: if the week containing
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** January 1 has four or more days in the new
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** year, then it is week 1, otherwise it is
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** week 53 of the previous year and the next
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** week is week 1)."
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** (ado, 5/24/93)
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*/
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/*
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** XXX--If January 1 falls on a Friday,
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** January 1-3 are part of week 53 of the
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** previous year. By analogy, if January
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** 1 falls on a Thursday, are December 29-31
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** of the PREVIOUS year part of week 1???
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** (ado 5/24/93)
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*/
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/*
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** You are understood not to expect this.
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*/
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case 'V': /* ISO 8601 week number */
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case 'G': /* ISO 8601 year (four digits) */
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case 'g': /* ISO 8601 year (two digits) */
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/*
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** From Arnold Robbins' strftime version 3.0: "the week number of the
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** year (the first Monday as the first day of week 1) as a decimal number
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** (01-53)."
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** (ado, 1993-05-24)
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**
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** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
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** "Week 01 of a year is per definition the first week which has the
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** Thursday in this year, which is equivalent to the week which contains
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** the fourth day of January. In other words, the first week of a new year
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** is the week which has the majority of its days in the new year. Week 01
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** might also contain days from the previous year and the week before week
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** 01 of a year is the last week (52 or 53) of the previous year even if
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** it contains days from the new year. A week starts with Monday (day 1)
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** and ends with Sunday (day 7). For example, the first week of the year
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** 1997 lasts from 1996-12-30 to 1997-01-05..."
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** (ado, 1996-01-02)
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*/
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{
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int i;
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int year;
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int yday;
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int wday;
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int w;
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i = (t->tm_yday + 10 - (t->tm_wday ?
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(t->tm_wday - 1) : 6)) / 7;
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if (i == 0) {
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year = t->tm_year + TM_YEAR_BASE;
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yday = t->tm_yday;
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wday = t->tm_wday;
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for ( ; ; ) {
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int len;
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int bot;
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int top;
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len = isleap(year) ?
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DAYSPERLYEAR :
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DAYSPERNYEAR;
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/*
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** What day of the week does
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** January 1 fall on?
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** What yday (-3 ... 3) does
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** the ISO year begin on?
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*/
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i = t->tm_wday -
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(t->tm_yday - 1);
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bot = ((yday + 11 - wday) %
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DAYSPERWEEK) - 3;
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/*
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** Fri Jan 1: 53
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** Sun Jan 1: 52
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** Sat Jan 1: 53 if previous
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** year a leap
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** year, else 52
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** What yday does the NEXT
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** ISO year begin on?
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*/
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if (i == TM_FRIDAY)
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i = 53;
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else if (i == TM_SUNDAY)
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i = 52;
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else i = isleap(t->tm_year +
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TM_YEAR_BASE) ?
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53 : 52;
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#ifdef XPG4_1994_04_09
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/*
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** As of 4/9/94, though,
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** XPG4 calls for 53
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** unconditionally.
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*/
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i = 53;
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#endif /* defined XPG4_1994_04_09 */
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top = bot -
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(len % DAYSPERWEEK);
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if (top < -3)
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top += DAYSPERWEEK;
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top += len;
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if (yday >= top) {
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++year;
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w = 1;
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break;
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}
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if (yday >= bot) {
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w = 1 + ((yday - bot) /
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DAYSPERWEEK);
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break;
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}
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--year;
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yday += isleap(year) ?
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DAYSPERLYEAR :
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DAYSPERNYEAR;
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}
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pt = _conv(i, "%02d", pt, ptlim);
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#ifdef XPG4_1994_04_09
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if ((w == 52
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&& t->tm_mon == TM_JANUARY)
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|| (w == 1
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&& t->tm_mon == TM_DECEMBER))
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w = 53;
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#endif /* defined XPG4_1994_04_09 */
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if (*format == 'V')
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pt = _conv(w, "%02d",
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pt, ptlim);
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else if (*format == 'g') {
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pt = _conv(year % 100, "%02d",
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pt, ptlim);
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} else pt = _conv(year, "%04d",
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pt, ptlim);
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}
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continue;
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case 'v':
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