]> git.saurik.com Git - apple/libc.git/blobdiff - stdtime/FreeBSD/strftime.c
Libc-1353.100.2.tar.gz
[apple/libc.git] / stdtime / FreeBSD / strftime.c
index fecc82159def7691667b55535d6333f71f20956f..0300e2b45ba8af4d66ff4d0fc58d28bfce0bf8f9 100644 (file)
@@ -7,7 +7,7 @@
  * duplicated in all such forms and that any documentation,
  * advertising materials, and other materials related to such
  * distribution and use acknowledge that the software was developed
- * by the University of California, Berkeley.  The name of the
+ * by the University of California, Berkeley. The name of the
  * University may not be used to endorse or promote products derived
  * from this software without specific prior written permission.
  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  */
 
-#ifndef lint
-#ifndef NOID
-static const char      elsieid[] = "@(#)strftime.c     7.64";
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wunreachable-code"
+
+#if 0
+static const char      elsieid[] = "@(#)strftime.3     8.3";
 /*
 ** Based on the UCB version with the ID appearing below.
 ** This is ANSIish only when "multibyte character == plain character".
 */
-#endif /* !defined NOID */
-#endif /* !defined lint */
+#endif
+
+#include "xlocale_private.h"
 
 #include "namespace.h"
 #include "private.h"
@@ -32,57 +35,92 @@ static const char   elsieid[] = "@(#)strftime.c     7.64";
 static const char      sccsid[] = "@(#)strftime.c      5.4 (Berkeley) 3/14/89";
 #endif /* LIBC_SCCS and not lint */
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/lib/libc/stdtime/strftime.c,v 1.40 2004/06/14 10:31:52 stefanf Exp $");
+__FBSDID("$FreeBSD: src/lib/libc/stdtime/strftime.c,v 1.44 2009/06/09 09:02:58 delphij Exp $");
 
 #include "tzfile.h"
+#include <time.h>
 #include <fcntl.h>
 #include <sys/stat.h>
 #include "un-namespace.h"
 #include "timelocal.h"
 
+#if !BUILDING_VARIANT
 static char *  _add(const char *, char *, const char *);
-static char *  _conv(int, const char *, char *, const char *);
-static char *  _fmt(const char *, const struct tm *, char *, const char *, int *);
-
-size_t strftime(char * __restrict, size_t, const char * __restrict,
-    const struct tm * __restrict);
+static char *  _conv(int, const char *, char *, const char *, locale_t);
+static char *  _yconv(int, int, int, int, char *, const char *, locale_t);
+#endif
+#define        _fmt    _st_fmt
+__private_extern__ char *      _fmt(const char *, const struct tm *, char *, const char *,
+                       int *, struct lc_time_T *, locale_t);
 
 extern char *  tzname[];
+extern long __darwin_altzone;          /* DST timezone offset */
+#define altzone __darwin_altzone
+__private_extern__ long _st_get_timezone(void);
 
 #ifndef YEAR_2000_NAME
 #define YEAR_2000_NAME "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
 #endif /* !defined YEAR_2000_NAME */
 
-
 #define IN_NONE        0
 #define IN_SOME        1
 #define IN_THIS        2
 #define IN_ALL 3
 
+#define PAD_DEFAULT    0
+#define PAD_LESS       1
+#define PAD_SPACE      2
+#define PAD_ZERO       3
+
+#ifndef BUILDING_VARIANT
+static const char * const fmt_padding[][4] = {
+       /* DEFAULT,     LESS,   SPACE,  ZERO */
+#define PAD_FMT_MONTHDAY       0
+#define PAD_FMT_HMS            0
+#define PAD_FMT_CENTURY                0
+#define PAD_FMT_SHORTYEAR      0
+#define PAD_FMT_MONTH          0
+#define PAD_FMT_WEEKOFYEAR     0
+#define PAD_FMT_DAYOFMONTH     0
+       { "%02d",       "%d",   "%2d",  "%02d" },
+#define PAD_FMT_SDAYOFMONTH    1
+#define PAD_FMT_SHMS           1
+       { "%2d",        "%d",   "%2d",  "%02d" },
+#define        PAD_FMT_DAYOFYEAR       2
+       { "%03d",       "%d",   "%3d",  "%03d" },
+#define PAD_FMT_YEAR           3
+       { "%04d",       "%d",   "%4d",  "%04d" }
+};
+#endif
+
+#define USG_COMPAT
+#define ALTZONE
+
 size_t
-strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
-    const struct tm * __restrict t)
+strftime_l(char * __restrict s, size_t maxsize, const char * __restrict format,
+    const struct tm * __restrict t, locale_t loc)
 {
        char *  p;
        int     warn;
 
+       NORMALIZE_LOCALE(loc);
        tzset();
        warn = IN_NONE;
-       p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
+       p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn, __get_current_time_locale(loc), loc);
 #ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU
        if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
-               (void) fprintf(stderr, "\n");
+               (void) fputs("\n", stderr);
                if (format == NULL)
-                       (void) fprintf(stderr, "NULL strftime format ");
-               else    (void) fprintf(stderr, "strftime format \"%s\" ",
+                       (void) fputs("NULL strftime format ", stderr);
+               else    (void) fprintf_l(stderr, loc, "strftime format \"%s\" ",
                                format);
-               (void) fprintf(stderr, "yields only two digits of years in ");
+               (void) fputs("yields only two digits of years in ", stderr);
                if (warn == IN_SOME)
-                       (void) fprintf(stderr, "some locales");
+                       (void) fputs("some locales", stderr);
                else if (warn == IN_THIS)
-                       (void) fprintf(stderr, "the current locale");
-               else    (void) fprintf(stderr, "all locales");
-               (void) fprintf(stderr, "\n");
+                       (void) fputs("the current locale", stderr);
+               else    (void) fputs("all locales", stderr);
+               (void) fputs("\n", stderr);
        }
 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
        if (p == s + maxsize)
@@ -91,21 +129,31 @@ strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
        return p - s;
 }
 
-static char *
-_fmt(format, t, pt, ptlim, warnp)
+size_t
+strftime(char * __restrict s, size_t maxsize, const char * __restrict format,
+    const struct tm * __restrict t)
+{
+       return strftime_l(s, maxsize, format, t, __current_locale());
+}
+
+#ifndef BUILDING_VARIANT
+__private_extern__ char *
+_fmt(format, t, pt, ptlim, warnp, tptr, loc)
 const char *           format;
 const struct tm * const        t;
 char *                 pt;
 const char * const     ptlim;
 int *                  warnp;
+struct lc_time_T *     tptr;
+locale_t               loc;
 {
-       int Ealternative, Oalternative;
-       struct lc_time_T *tptr = __get_current_time_locale();
+       int Ealternative, Oalternative, PadIndex;
 
        for ( ; *format; ++format) {
                if (*format == '%') {
                        Ealternative = 0;
                        Oalternative = 0;
+                       PadIndex         = PAD_DEFAULT;
 label:
                        switch (*++format) {
                        case '\0':
@@ -140,19 +188,19 @@ label:
                        case 'C':
                                /*
                                ** %C used to do a...
-                               **      _fmt("%a %b %e %X %Y", t);
+                               **      _fmt("%a %b %e %X %Y", t, tptr, loc);
                                ** ...whereas now POSIX 1003.2 calls for
                                ** something completely different.
                                ** (ado, 1993-05-24)
                                */
-                               pt = _conv((t->tm_year + TM_YEAR_BASE) / 100,
-                                       "%02d", pt, ptlim);
+                               pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
+                                       pt, ptlim, loc);
                                continue;
                        case 'c':
                                {
                                int warn2 = IN_SOME;
 
-                               pt = _fmt(tptr->c_fmt, t, pt, ptlim, warnp);
+                               pt = _fmt(tptr->c_fmt, t, pt, ptlim, &warn2, tptr, loc);
                                if (warn2 == IN_ALL)
                                        warn2 = IN_THIS;
                                if (warn2 > *warnp)
@@ -160,10 +208,11 @@ label:
                                }
                                continue;
                        case 'D':
-                               pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
+                               pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp, tptr, loc);
                                continue;
                        case 'd':
-                               pt = _conv(t->tm_mday, "%02d", pt, ptlim);
+                               pt = _conv(t->tm_mday, fmt_padding[PAD_FMT_DAYOFMONTH][PadIndex],
+                                       pt, ptlim, loc);
                                continue;
                        case 'E':
                                if (Ealternative || Oalternative)
@@ -188,34 +237,38 @@ label:
                                Oalternative++;
                                goto label;
                        case 'e':
-                               pt = _conv(t->tm_mday, "%2d", pt, ptlim);
+                               pt = _conv(t->tm_mday,
+                                       fmt_padding[PAD_FMT_SDAYOFMONTH][PadIndex], pt, ptlim, loc);
                                continue;
                        case 'F':
-                               pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
+                               pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp, tptr, loc);
                                continue;
                        case 'H':
-                               pt = _conv(t->tm_hour, "%02d", pt, ptlim);
+                               pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_HMS][PadIndex],
+                                       pt, ptlim, loc);
                                continue;
                        case 'I':
                                pt = _conv((t->tm_hour % 12) ?
                                        (t->tm_hour % 12) : 12,
-                                       "%02d", pt, ptlim);
+                                       fmt_padding[PAD_FMT_HMS][PadIndex], pt, ptlim, loc);
                                continue;
                        case 'j':
-                               pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
+                               pt = _conv(t->tm_yday + 1,
+                                       fmt_padding[PAD_FMT_DAYOFYEAR][PadIndex], pt, ptlim, loc);
                                continue;
                        case 'k':
                                /*
                                ** This used to be...
                                **      _conv(t->tm_hour % 12 ?
-                               **              t->tm_hour % 12 : 12, 2, ' ');
+                               **              t->tm_hour % 12 : 12, 2, ' ', loc);
                                ** ...and has been changed to the below to
                                ** match SunOS 4.1.1 and Arnold Robbins'
-                               ** strftime version 3.0.  That is, "%k" and
+                               ** strftime version 3.0. That is, "%k" and
                                ** "%l" have been swapped.
                                ** (ado, 1993-05-24)
                                */
-                               pt = _conv(t->tm_hour, "%2d", pt, ptlim);
+                               pt = _conv(t->tm_hour, fmt_padding[PAD_FMT_SHMS][PadIndex],
+                                       pt, ptlim, loc);
                                continue;
 #ifdef KITCHEN_SINK
                        case 'K':
@@ -231,19 +284,21 @@ label:
                                **      _conv(t->tm_hour, 2, ' ');
                                ** ...and has been changed to the below to
                                ** match SunOS 4.1.1 and Arnold Robbin's
-                               ** strftime version 3.0.  That is, "%k" and
+                               ** strftime version 3.0. That is, "%k" and
                                ** "%l" have been swapped.
                                ** (ado, 1993-05-24)
                                */
                                pt = _conv((t->tm_hour % 12) ?
                                        (t->tm_hour % 12) : 12,
-                                       "%2d", pt, ptlim);
+                                       fmt_padding[PAD_FMT_SHMS][PadIndex], pt, ptlim, loc);
                                continue;
                        case 'M':
-                               pt = _conv(t->tm_min, "%02d", pt, ptlim);
+                               pt = _conv(t->tm_min, fmt_padding[PAD_FMT_HMS][PadIndex],
+                                       pt, ptlim, loc);
                                continue;
                        case 'm':
-                               pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
+                               pt = _conv(t->tm_mon + 1,
+                                       fmt_padding[PAD_FMT_MONTH][PadIndex], pt, ptlim, loc);
                                continue;
                        case 'n':
                                pt = _add("\n", pt, ptlim);
@@ -255,14 +310,15 @@ label:
                                        pt, ptlim);
                                continue;
                        case 'R':
-                               pt = _fmt("%H:%M", t, pt, ptlim, warnp);
+                               pt = _fmt("%H:%M", t, pt, ptlim, warnp, tptr, loc);
                                continue;
                        case 'r':
                                pt = _fmt(tptr->ampm_fmt, t, pt, ptlim,
-                                       warnp);
+                                       warnp, tptr, loc);
                                continue;
                        case 'S':
-                               pt = _conv(t->tm_sec, "%02d", pt, ptlim);
+                               pt = _conv(t->tm_sec, fmt_padding[PAD_FMT_HMS][PadIndex],
+                                       pt, ptlim, loc);
                                continue;
                        case 's':
                                {
@@ -274,15 +330,15 @@ label:
                                        tm = *t;
                                        mkt = mktime(&tm);
                                        if (TYPE_SIGNED(time_t))
-                                               (void) sprintf(buf, "%ld",
+                                               (void) sprintf_l(buf, loc, "%ld",
                                                        (long) mkt);
-                                       else    (void) sprintf(buf, "%lu",
+                                       else    (void) sprintf_l(buf, loc, "%lu",
                                                        (unsigned long) mkt);
                                        pt = _add(buf, pt, ptlim);
                                }
                                continue;
                        case 'T':
-                               pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
+                               pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp, tptr, loc);
                                continue;
                        case 't':
                                pt = _add("\t", pt, ptlim);
@@ -290,7 +346,7 @@ label:
                        case 'U':
                                pt = _conv((t->tm_yday + DAYSPERWEEK -
                                        t->tm_wday) / DAYSPERWEEK,
-                                       "%02d", pt, ptlim);
+                                       fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim, loc);
                                continue;
                        case 'u':
                                /*
@@ -301,13 +357,13 @@ label:
                                */
                                pt = _conv((t->tm_wday == 0) ?
                                        DAYSPERWEEK : t->tm_wday,
-                                       "%d", pt, ptlim);
+                                       "%d", pt, ptlim, loc);
                                continue;
                        case 'V':       /* ISO 8601 week number */
                        case 'G':       /* ISO 8601 year (four digits) */
                        case 'g':       /* ISO 8601 year (two digits) */
 /*
-** From Arnold Robbins' strftime version 3.0:  "the week number of the
+** From Arnold Robbins' strftime version 3.0: "the week number of the
 ** year (the first Monday as the first day of week 1) as a decimal number
 ** (01-53)."
 ** (ado, 1993-05-24)
@@ -320,17 +376,19 @@ label:
 ** might also contain days from the previous year and the week before week
 ** 01 of a year is the last week (52 or 53) of the previous year even if
 ** it contains days from the new year. A week starts with Monday (day 1)
-** and ends with Sunday (day 7).  For example, the first week of the year
+** and ends with Sunday (day 7). For example, the first week of the year
 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
 ** (ado, 1996-01-02)
 */
                                {
                                        int     year;
+                                       int     base;
                                        int     yday;
                                        int     wday;
                                        int     w;
 
-                                       year = t->tm_year + TM_YEAR_BASE;
+                                       year = t->tm_year;
+                                       base = TM_YEAR_BASE;
                                        yday = t->tm_yday;
                                        wday = t->tm_wday;
                                        for ( ; ; ) {
@@ -338,7 +396,7 @@ label:
                                                int     bot;
                                                int     top;
 
-                                               len = isleap(year) ?
+                                               len = isleap_sum(year, base) ?
                                                        DAYSPERLYEAR :
                                                        DAYSPERNYEAR;
                                                /*
@@ -357,7 +415,7 @@ label:
                                                        top += DAYSPERWEEK;
                                                top += len;
                                                if (yday >= top) {
-                                                       ++year;
+                                                       ++base;
                                                        w = 1;
                                                        break;
                                                }
@@ -366,27 +424,27 @@ label:
                                                                DAYSPERWEEK);
                                                        break;
                                                }
-                                               --year;
-                                               yday += isleap(year) ?
+                                               --base;
+                                               yday += isleap_sum(year, base) ?
                                                        DAYSPERLYEAR :
                                                        DAYSPERNYEAR;
                                        }
 #ifdef XPG4_1994_04_09
-                                       if ((w == 52
-                                            && t->tm_mon == TM_JANUARY)
-                                           || (w == 1
-                                               && t->tm_mon == TM_DECEMBER))
-                                               w = 53;
+                                       if ((w == 52 &&
+                                               t->tm_mon == TM_JANUARY) ||
+                                               (w == 1 &&
+                                               t->tm_mon == TM_DECEMBER))
+                                                       w = 53;
 #endif /* defined XPG4_1994_04_09 */
                                        if (*format == 'V')
-                                               pt = _conv(w, "%02d",
-                                                       pt, ptlim);
+                                               pt = _conv(w, fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex],
+                                                       pt, ptlim, loc);
                                        else if (*format == 'g') {
                                                *warnp = IN_ALL;
-                                               pt = _conv(year % 100, "%02d",
-                                                       pt, ptlim);
-                                       } else  pt = _conv(year, "%04d",
-                                                       pt, ptlim);
+                                               pt = _yconv(year, base, 0, 1,
+                                                       pt, ptlim, loc);
+                                       } else  pt = _yconv(year, base, 1, 1,
+                                                       pt, ptlim, loc);
                                }
                                continue;
                        case 'v':
@@ -395,26 +453,26 @@ label:
                                ** "date as dd-bbb-YYYY"
                                ** (ado, 1993-05-24)
                                */
-                               pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
+                               pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp, tptr, loc);
                                continue;
                        case 'W':
                                pt = _conv((t->tm_yday + DAYSPERWEEK -
                                        (t->tm_wday ?
                                        (t->tm_wday - 1) :
                                        (DAYSPERWEEK - 1))) / DAYSPERWEEK,
-                                       "%02d", pt, ptlim);
+                                       fmt_padding[PAD_FMT_WEEKOFYEAR][PadIndex], pt, ptlim, loc);
                                continue;
                        case 'w':
-                               pt = _conv(t->tm_wday, "%d", pt, ptlim);
+                               pt = _conv(t->tm_wday, "%d", pt, ptlim, loc);
                                continue;
                        case 'X':
-                               pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp);
+                               pt = _fmt(tptr->X_fmt, t, pt, ptlim, warnp, tptr, loc);
                                continue;
                        case 'x':
                                {
                                int     warn2 = IN_SOME;
 
-                               pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2);
+                               pt = _fmt(tptr->x_fmt, t, pt, ptlim, &warn2, tptr, loc);
                                if (warn2 == IN_ALL)
                                        warn2 = IN_THIS;
                                if (warn2 > *warnp)
@@ -423,12 +481,12 @@ label:
                                continue;
                        case 'y':
                                *warnp = IN_ALL;
-                               pt = _conv((t->tm_year + TM_YEAR_BASE) % 100,
-                                       "%02d", pt, ptlim);
+                               pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
+                                       pt, ptlim, loc);
                                continue;
                        case 'Y':
-                               pt = _conv(t->tm_year + TM_YEAR_BASE, "%04d",
-                                       pt, ptlim);
+                               pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
+                                       pt, ptlim, loc);
                                continue;
                        case 'Z':
 #ifdef TM_ZONE
@@ -452,18 +510,18 @@ label:
 
                                if (t->tm_isdst < 0)
                                        continue;
-#ifdef TM_GMTOFF
+#if defined(TM_GMTOFF) && !__DARWIN_UNIX03
                                diff = t->TM_GMTOFF;
-#else /* !defined TM_GMTOFF */
+#else /* !defined TM_GMTOFF || __DARWIN_UNIX03 */
                                /*
                                ** C99 says that the UTC offset must
                                ** be computed by looking only at
-                               ** tm_isdst.  This requirement is
+                               ** tm_isdst. This requirement is
                                ** incorrect, since it means the code
                                ** must rely on magic (in this case
                                ** altzone and timezone), and the
                                ** magic might not have the correct
-                               ** offset.  Doing things correctly is
+                               ** offset. Doing things correctly is
                                ** tricky and requires disobeying C99;
                                ** see GNU C strftime for details.
                                ** For now, punt and conform to the
@@ -476,7 +534,7 @@ label:
                                */
                                if (t->tm_isdst == 0)
 #ifdef USG_COMPAT
-                                       diff = -timezone;
+                                       diff = -_st_get_timezone();
 #else /* !defined USG_COMPAT */
                                        continue;
 #endif /* !defined USG_COMPAT */
@@ -486,25 +544,42 @@ label:
 #else /* !defined ALTZONE */
                                        continue;
 #endif /* !defined ALTZONE */
-#endif /* !defined TM_GMTOFF */
+#endif /* !defined TM_GMTOFF || __DARWIN_UNIX03 */
                                if (diff < 0) {
                                        sign = "-";
                                        diff = -diff;
                                } else  sign = "+";
                                pt = _add(sign, pt, ptlim);
-                               diff /= 60;
-                               pt = _conv((diff/60)*100 + diff%60,
-                                       "%04d", pt, ptlim);
+                               diff /= SECSPERMIN;
+                               diff = (diff / MINSPERHOUR) * 100 +
+                                       (diff % MINSPERHOUR);
+                               pt = _conv(diff,
+                                       fmt_padding[PAD_FMT_YEAR][PadIndex], pt, ptlim, loc);
                                }
                                continue;
                        case '+':
                                pt = _fmt(tptr->date_fmt, t, pt, ptlim,
-                                       warnp);
+                                       warnp, tptr, loc);
                                continue;
+                       case '-':
+                               if (PadIndex != PAD_DEFAULT)
+                                       break;
+                               PadIndex = PAD_LESS;
+                               goto label;
+                       case '_':
+                               if (PadIndex != PAD_DEFAULT)
+                                       break;
+                               PadIndex = PAD_SPACE;
+                               goto label;
+                       case '0':
+                               if (PadIndex != PAD_DEFAULT)
+                                       break;
+                               PadIndex = PAD_ZERO;
+                               goto label;
                        case '%':
                        /*
                        ** X311J/88-090 (4.12.3.5): if conversion char is
-                       ** undefined, behavior is undefined.  Print out the
+                       ** undefined, behavior is undefined. Print out the
                        ** character itself as printf(3) also does.
                        */
                        default:
@@ -519,15 +594,16 @@ label:
 }
 
 static char *
-_conv(n, format, pt, ptlim)
+_conv(n, format, pt, ptlim, loc)
 const int              n;
 const char * const     format;
 char * const           pt;
 const char * const     ptlim;
+locale_t               loc;
 {
        char    buf[INT_STRLEN_MAXIMUM(int) + 1];
 
-       (void) sprintf(buf, format, n);
+       (void) sprintf_l(buf, loc, format, n);
        return _add(buf, pt, ptlim);
 }
 
@@ -541,3 +617,47 @@ const char * const ptlim;
                ++pt;
        return pt;
 }
+
+/*
+** POSIX and the C Standard are unclear or inconsistent about
+** what %C and %y do if the year is negative or exceeds 9999.
+** Use the convention that %C concatenated with %y yields the
+** same output as %Y, and that %Y contains at least 4 bytes,
+** with more only if necessary.
+*/
+
+static char *
+_yconv(a, b, convert_top, convert_yy, pt, ptlim, loc)
+const int              a;
+const int              b;
+const int              convert_top;
+const int              convert_yy;
+char *                 pt;
+const char * const     ptlim;
+locale_t               loc;
+{
+       register int    lead;
+       register int    trail;
+
+#define DIVISOR        100
+       trail = a % DIVISOR + b % DIVISOR;
+       lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
+       trail %= DIVISOR;
+       if (trail < 0 && lead > 0) {
+               trail += DIVISOR;
+               --lead;
+       } else if (lead < 0 && trail > 0) {
+               trail -= DIVISOR;
+               ++lead;
+       }
+       if (convert_top) {
+               if (lead == 0 && trail < 0)
+                       pt = _add("-0", pt, ptlim);
+               else    pt = _conv(lead, "%02d", pt, ptlim, loc);
+       }
+       if (convert_yy)
+               pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim, loc);
+       return pt;
+}
+#endif /* !BUILDING_VARIANT */
+#pragma clang diagnostic pop