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1 #ifndef lint
2 #ifndef NOID
3 static char elsieid[] = "@(#)strftime.c 8.1";
4 /*
5 ** Based on the UCB version with the ID appearing below.
6 ** This is ANSIish only when "multibyte character == plain character".
7 */
8 #endif /* !defined NOID */
9 #endif /* !defined lint */
10 
11 #include "private.h"
12 
13 /*
14 ** Copyright (c) 1989 The Regents of the University of California.
15 ** All rights reserved.
16 **
17 ** Redistribution and use in source and binary forms are permitted
18 ** provided that the above copyright notice and this paragraph are
19 ** duplicated in all such forms and that any documentation,
20 ** advertising materials, and other materials related to such
21 ** distribution and use acknowledge that the software was developed
22 ** by the University of California, Berkeley. The name of the
23 ** University may not be used to endorse or promote products derived
24 ** from this software without specific prior written permission.
25 ** THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
26 ** IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
27 ** WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
28 */
29 
30 #ifndef LIBC_SCCS
31 #ifndef lint
32 static const char   sccsid[] = "@(#)strftime.c  5.4 (Berkeley) 3/14/89";
33 #endif /* !defined lint */
34 #endif /* !defined LIBC_SCCS */
35 
36 #include "tzfile.h"
37 #include "fcntl.h"
38 #include "locale.h"
39 #include <ctype.h>
40 #include <time64.h>
41 #include <bionic_time.h>  /* for strftime_tz */
42 
43 /* struct lc_time_T is now defined as strftime_locale
44  * in <time.h>
45  */
46 #if 1
47 #define  lc_time_T    strftime_locale
48 #else
49 struct lc_time_T {
50     const char *    mon[MONSPERYEAR];
51     const char *    month[MONSPERYEAR];
52     const char *    wday[DAYSPERWEEK];
53     const char *    weekday[DAYSPERWEEK];
54     const char *    X_fmt;
55     const char *    x_fmt;
56     const char *    c_fmt;
57     const char *    am;
58     const char *    pm;
59     const char *    date_fmt;
60 };
61 #endif
62 
63 #define Locale  (&C_time_locale)
64 
65 static const struct lc_time_T   C_time_locale = {
66     {
67         "Jan", "Feb", "Mar", "Apr", "May", "Jun",
68         "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
69     }, {
70         "January", "February", "March", "April", "May", "June",
71         "July", "August", "September", "October", "November", "December"
72     }, {
73         "January", "February", "March", "April", "May", "June",
74         "July", "August", "September", "October", "November", "December"
75     }, {
76         "Sun", "Mon", "Tue", "Wed",
77         "Thu", "Fri", "Sat"
78     }, {
79         "Sunday", "Monday", "Tuesday", "Wednesday",
80         "Thursday", "Friday", "Saturday"
81     },
82 
83     /* X_fmt */
84     "%H:%M:%S",
85 
86     /*
87     ** x_fmt
88     ** C99 requires this format.
89     ** Using just numbers (as here) makes Quakers happier;
90     ** it's also compatible with SVR4.
91     */
92     "%m/%d/%y",
93 
94     /*
95     ** c_fmt
96     ** C99 requires this format.
97     ** Previously this code used "%D %X", but we now conform to C99.
98     ** Note that
99     **  "%a %b %d %H:%M:%S %Y"
100     ** is used by Solaris 2.3.
101     */
102     "%a %b %e %T %Y",
103 
104     /* am */
105     "AM",
106 
107     /* pm */
108     "PM",
109 
110     /* date_fmt */
111     "%a %b %e %H:%M:%S %Z %Y"
112 };
113 
114 static char *   _add P((const char *, char *, const char *, int));
115 static char *   _conv P((int, const char *, char *, const char *));
116 static char *   _fmt P((const char *, const struct tm *, char *, const char *,
117             int *, const struct strftime_locale*));
118 static char *   _yconv P((int, int, int, int, char *, const char *, int));
119 static char *   getformat P((int, char *, char *, char *, char *));
120 
121 extern char *   tzname[];
122 
123 #ifndef YEAR_2000_NAME
124 #define YEAR_2000_NAME  "CHECK_STRFTIME_FORMATS_FOR_TWO_DIGIT_YEARS"
125 #endif /* !defined YEAR_2000_NAME */
126 
127 #define IN_NONE 0
128 #define IN_SOME 1
129 #define IN_THIS 2
130 #define IN_ALL  3
131 
132 #define FORCE_LOWER_CASE 0x100
133 
134 size_t
strftime(s,maxsize,format,t)135 strftime(s, maxsize, format, t)
136 char * const        s;
137 const size_t        maxsize;
138 const char * const  format;
139 const struct tm * const t;
140 {
141     return strftime_tz(s, maxsize, format, t, Locale);
142 }
143 
144 size_t
strftime_tz(s,maxsize,format,t,locale)145 strftime_tz(s, maxsize, format, t, locale)
146 char * const        s;
147 const size_t        maxsize;
148 const char * const  format;
149 const struct tm * const t;
150 const struct strftime_locale *locale;
151 {
152     char *  p;
153     int warn;
154 
155     tzset();
156     warn = IN_NONE;
157     p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn, locale);
158 #if 0  /* ifndef NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
159     if (warn != IN_NONE && getenv(YEAR_2000_NAME) != NULL) {
160         (void) fprintf(stderr, "\n");
161         if (format == NULL)
162             (void) fprintf(stderr, "NULL strftime format ");
163         else    (void) fprintf(stderr, "strftime format \"%s\" ",
164                 format);
165         (void) fprintf(stderr, "yields only two digits of years in ");
166         if (warn == IN_SOME)
167             (void) fprintf(stderr, "some locales");
168         else if (warn == IN_THIS)
169             (void) fprintf(stderr, "the current locale");
170         else    (void) fprintf(stderr, "all locales");
171         (void) fprintf(stderr, "\n");
172     }
173 #endif /* !defined NO_RUN_TIME_WARNINGS_ABOUT_YEAR_2000_PROBLEMS_THANK_YOU */
174     if (p == s + maxsize)
175         return 0;
176     *p = '\0';
177     return p - s;
178 }
179 
getformat(int modifier,char * normal,char * underscore,char * dash,char * zero)180 static char *getformat(int modifier, char *normal, char *underscore,
181                        char *dash, char *zero) {
182     switch (modifier) {
183     case '_':
184         return underscore;
185 
186     case '-':
187         return dash;
188 
189     case '0':
190         return zero;
191     }
192 
193     return normal;
194 }
195 
196 static char *
_fmt(format,t,pt,ptlim,warnp,locale)197 _fmt(format, t, pt, ptlim, warnp, locale)
198 const char *        format;
199 const struct tm * const t;
200 char *          pt;
201 const char * const  ptlim;
202 int *           warnp;
203 const struct strftime_locale* locale;
204 {
205     for ( ; *format; ++format) {
206         if (*format == '%') {
207             int modifier = 0;
208 label:
209             switch (*++format) {
210             case '\0':
211                 --format;
212                 break;
213             case 'A':
214                 pt = _add((t->tm_wday < 0 ||
215                     t->tm_wday >= DAYSPERWEEK) ?
216                     "?" : locale->weekday[t->tm_wday],
217                     pt, ptlim, modifier);
218                 continue;
219             case 'a':
220                 pt = _add((t->tm_wday < 0 ||
221                     t->tm_wday >= DAYSPERWEEK) ?
222                     "?" : locale->wday[t->tm_wday],
223                     pt, ptlim, modifier);
224                 continue;
225             case 'B':
226                 if (modifier == '-') {
227                     pt = _add((t->tm_mon < 0 ||
228                                 t->tm_mon >= MONSPERYEAR) ?
229                                 "?" : locale->standalone_month[t->tm_mon],
230                                 pt, ptlim, modifier);
231                 } else {
232                     pt = _add((t->tm_mon < 0 ||
233                                 t->tm_mon >= MONSPERYEAR) ?
234                                 "?" : locale->month[t->tm_mon],
235                                 pt, ptlim, modifier);
236                 }
237                 continue;
238             case 'b':
239             case 'h':
240                 pt = _add((t->tm_mon < 0 ||
241                     t->tm_mon >= MONSPERYEAR) ?
242                     "?" : locale->mon[t->tm_mon],
243                     pt, ptlim, modifier);
244                 continue;
245             case 'C':
246                 /*
247                 ** %C used to do a...
248                 **  _fmt("%a %b %e %X %Y", t);
249                 ** ...whereas now POSIX 1003.2 calls for
250                 ** something completely different.
251                 ** (ado, 1993-05-24)
252                 */
253                 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
254                     pt, ptlim, modifier);
255                 continue;
256             case 'c':
257                 {
258                 int warn2 = IN_SOME;
259 
260                 pt = _fmt(locale->c_fmt, t, pt, ptlim, warnp, locale);
261                 if (warn2 == IN_ALL)
262                     warn2 = IN_THIS;
263                 if (warn2 > *warnp)
264                     *warnp = warn2;
265                 }
266                 continue;
267             case 'D':
268                                 pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp, locale);
269                 continue;
270             case 'd':
271                                 pt = _conv(t->tm_mday,
272                                            getformat(modifier, "%02d",
273                                                      "%2d", "%d", "%02d"),
274                                            pt, ptlim);
275                 continue;
276             case 'E':
277             case 'O':
278                 /*
279                 ** C99 locale modifiers.
280                 ** The sequences
281                 **  %Ec %EC %Ex %EX %Ey %EY
282                 **  %Od %oe %OH %OI %Om %OM
283                 **  %OS %Ou %OU %OV %Ow %OW %Oy
284                 ** are supposed to provide alternate
285                 ** representations.
286                 */
287                 goto label;
288             case '_':
289             case '-':
290             case '0':
291             case '^':
292             case '#':
293                 modifier = *format;
294                 goto label;
295             case 'e':
296                 pt = _conv(t->tm_mday,
297                                            getformat(modifier, "%2d",
298                                                      "%2d", "%d", "%02d"),
299                                            pt, ptlim);
300                 continue;
301             case 'F':
302                 pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp, locale);
303                 continue;
304             case 'H':
305                 pt = _conv(t->tm_hour,
306                                            getformat(modifier, "%02d",
307                                                      "%2d", "%d", "%02d"),
308                                            pt, ptlim);
309                 continue;
310             case 'I':
311                 pt = _conv((t->tm_hour % 12) ?
312                     (t->tm_hour % 12) : 12,
313                     getformat(modifier, "%02d",
314                                                   "%2d", "%d", "%02d"),
315                                         pt, ptlim);
316                 continue;
317             case 'j':
318                 pt = _conv(t->tm_yday + 1,
319                            getformat(modifier, "%03d", "%3d", "%d", "%03d"),
320                            pt, ptlim);
321                 continue;
322             case 'k':
323                 /*
324                 ** This used to be...
325                 **  _conv(t->tm_hour % 12 ?
326                 **      t->tm_hour % 12 : 12, 2, ' ');
327                 ** ...and has been changed to the below to
328                 ** match SunOS 4.1.1 and Arnold Robbins'
329                 ** strftime version 3.0. That is, "%k" and
330                 ** "%l" have been swapped.
331                 ** (ado, 1993-05-24)
332                 */
333                 pt = _conv(t->tm_hour,
334                                            getformat(modifier, "%2d",
335                                                      "%2d", "%d", "%02d"),
336                                            pt, ptlim);
337                 continue;
338 #ifdef KITCHEN_SINK
339             case 'K':
340                 /*
341                 ** After all this time, still unclaimed!
342                 */
343                 pt = _add("kitchen sink", pt, ptlim, modifier);
344                 continue;
345 #endif /* defined KITCHEN_SINK */
346             case 'l':
347                 /*
348                 ** This used to be...
349                 **  _conv(t->tm_hour, 2, ' ');
350                 ** ...and has been changed to the below to
351                 ** match SunOS 4.1.1 and Arnold Robbin's
352                 ** strftime version 3.0. That is, "%k" and
353                 ** "%l" have been swapped.
354                 ** (ado, 1993-05-24)
355                 */
356                 pt = _conv((t->tm_hour % 12) ?
357                     (t->tm_hour % 12) : 12,
358                     getformat(modifier, "%2d",
359                                                   "%2d", "%d", "%02d"),
360                                         pt, ptlim);
361                 continue;
362             case 'M':
363                 pt = _conv(t->tm_min,
364                                            getformat(modifier, "%02d",
365                                                      "%2d", "%d", "%02d"),
366                                            pt, ptlim);
367                 continue;
368             case 'm':
369                 pt = _conv(t->tm_mon + 1,
370                                            getformat(modifier, "%02d",
371                                                      "%2d", "%d", "%02d"),
372                                            pt, ptlim);
373                 continue;
374             case 'n':
375                 pt = _add("\n", pt, ptlim, modifier);
376                 continue;
377             case 'p':
378                 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
379                     locale->pm :
380                     locale->am,
381                     pt, ptlim, modifier);
382                 continue;
383             case 'P':
384                 pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
385                     locale->pm :
386                     locale->am,
387                     pt, ptlim, FORCE_LOWER_CASE);
388                 continue;
389             case 'R':
390                 pt = _fmt("%H:%M", t, pt, ptlim, warnp, locale);
391                 continue;
392             case 'r':
393                 pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp, locale);
394                 continue;
395             case 'S':
396                 pt = _conv(t->tm_sec,
397                                            getformat(modifier, "%02d",
398                                                      "%2d", "%d", "%02d"),
399                                            pt, ptlim);
400                 continue;
401             case 's':
402                 {
403                     struct tm   tm;
404                     char        buf[INT_STRLEN_MAXIMUM(
405                                 time64_t) + 1];
406                     time64_t    mkt;
407 
408                     tm = *t;
409                     mkt = mktime64(&tm);
410                     if (TYPE_SIGNED(time64_t))
411                         (void) snprintf(buf, sizeof(buf), "%lld",
412                             (long long) mkt);
413                     else    (void) snprintf(buf, sizeof(buf), "%llu",
414                             (unsigned long long) mkt);
415                     pt = _add(buf, pt, ptlim, modifier);
416                 }
417                 continue;
418             case 'T':
419                 pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp, locale);
420                 continue;
421             case 't':
422                 pt = _add("\t", pt, ptlim, modifier);
423                 continue;
424             case 'U':
425                 pt = _conv((t->tm_yday + DAYSPERWEEK -
426                     t->tm_wday) / DAYSPERWEEK,
427                     getformat(modifier, "%02d",
428                                                   "%2d", "%d", "%02d"),
429                                         pt, ptlim);
430                 continue;
431             case 'u':
432                 /*
433                 ** From Arnold Robbins' strftime version 3.0:
434                 ** "ISO 8601: Weekday as a decimal number
435                 ** [1 (Monday) - 7]"
436                 ** (ado, 1993-05-24)
437                 */
438                 pt = _conv((t->tm_wday == 0) ?
439                     DAYSPERWEEK : t->tm_wday, "%d", pt, ptlim);
440                 continue;
441             case 'V':   /* ISO 8601 week number */
442             case 'G':   /* ISO 8601 year (four digits) */
443             case 'g':   /* ISO 8601 year (two digits) */
444 /*
445 ** From Arnold Robbins' strftime version 3.0: "the week number of the
446 ** year (the first Monday as the first day of week 1) as a decimal number
447 ** (01-53)."
448 ** (ado, 1993-05-24)
449 **
450 ** From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
451 ** "Week 01 of a year is per definition the first week which has the
452 ** Thursday in this year, which is equivalent to the week which contains
453 ** the fourth day of January. In other words, the first week of a new year
454 ** is the week which has the majority of its days in the new year. Week 01
455 ** might also contain days from the previous year and the week before week
456 ** 01 of a year is the last week (52 or 53) of the previous year even if
457 ** it contains days from the new year. A week starts with Monday (day 1)
458 ** and ends with Sunday (day 7). For example, the first week of the year
459 ** 1997 lasts from 1996-12-30 to 1997-01-05..."
460 ** (ado, 1996-01-02)
461 */
462                 {
463                     int year;
464                     int base;
465                     int yday;
466                     int wday;
467                     int w;
468 
469                     year = t->tm_year;
470                     base = TM_YEAR_BASE;
471                     yday = t->tm_yday;
472                     wday = t->tm_wday;
473                     for ( ; ; ) {
474                         int len;
475                         int bot;
476                         int top;
477 
478                         len = isleap_sum(year, base) ?
479                             DAYSPERLYEAR :
480                             DAYSPERNYEAR;
481                         /*
482                         ** What yday (-3 ... 3) does
483                         ** the ISO year begin on?
484                         */
485                         bot = ((yday + 11 - wday) %
486                             DAYSPERWEEK) - 3;
487                         /*
488                         ** What yday does the NEXT
489                         ** ISO year begin on?
490                         */
491                         top = bot -
492                             (len % DAYSPERWEEK);
493                         if (top < -3)
494                             top += DAYSPERWEEK;
495                         top += len;
496                         if (yday >= top) {
497                             ++base;
498                             w = 1;
499                             break;
500                         }
501                         if (yday >= bot) {
502                             w = 1 + ((yday - bot) /
503                                 DAYSPERWEEK);
504                             break;
505                         }
506                         --base;
507                         yday += isleap_sum(year, base) ?
508                             DAYSPERLYEAR :
509                             DAYSPERNYEAR;
510                     }
511 #ifdef XPG4_1994_04_09
512                     if ((w == 52 &&
513                         t->tm_mon == TM_JANUARY) ||
514                         (w == 1 &&
515                         t->tm_mon == TM_DECEMBER))
516                             w = 53;
517 #endif /* defined XPG4_1994_04_09 */
518                     if (*format == 'V')
519                         pt = _conv(w,
520                                                            getformat(modifier,
521                                                                      "%02d",
522                                                                      "%2d",
523                                                                      "%d",
524                                                                      "%02d"),
525                                pt, ptlim);
526                     else if (*format == 'g') {
527                         *warnp = IN_ALL;
528                         pt = _yconv(year, base, 0, 1,
529                             pt, ptlim, modifier);
530                     } else  pt = _yconv(year, base, 1, 1,
531                             pt, ptlim, modifier);
532                 }
533                 continue;
534             case 'v':
535                 /*
536                 ** From Arnold Robbins' strftime version 3.0:
537                 ** "date as dd-bbb-YYYY"
538                 ** (ado, 1993-05-24)
539                 */
540                 pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp, locale);
541                 continue;
542             case 'W':
543                 pt = _conv((t->tm_yday + DAYSPERWEEK -
544                     (t->tm_wday ?
545                     (t->tm_wday - 1) :
546                     (DAYSPERWEEK - 1))) / DAYSPERWEEK,
547                     getformat(modifier, "%02d",
548                                                   "%2d", "%d", "%02d"),
549                                         pt, ptlim);
550                 continue;
551             case 'w':
552                 pt = _conv(t->tm_wday, "%d", pt, ptlim);
553                 continue;
554             case 'X':
555                 pt = _fmt(locale->X_fmt, t, pt, ptlim, warnp, locale);
556                 continue;
557             case 'x':
558                 {
559                 int warn2 = IN_SOME;
560 
561                 pt = _fmt(locale->x_fmt, t, pt, ptlim, &warn2, locale);
562                 if (warn2 == IN_ALL)
563                     warn2 = IN_THIS;
564                 if (warn2 > *warnp)
565                     *warnp = warn2;
566                 }
567                 continue;
568             case 'y':
569                 *warnp = IN_ALL;
570                 pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
571                     pt, ptlim, modifier);
572                 continue;
573             case 'Y':
574                 pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
575                     pt, ptlim, modifier);
576                 continue;
577             case 'Z':
578 #ifdef TM_ZONE
579                 if (t->TM_ZONE != NULL)
580                     pt = _add(t->TM_ZONE, pt, ptlim,
581                                                   modifier);
582                 else
583 #endif /* defined TM_ZONE */
584                 if (t->tm_isdst >= 0)
585                     pt = _add(tzname[t->tm_isdst != 0],
586                         pt, ptlim, modifier);
587                 /*
588                 ** C99 says that %Z must be replaced by the
589                 ** empty string if the time zone is not
590                 ** determinable.
591                 */
592                 continue;
593             case 'z':
594                 {
595                 int     diff;
596                 char const *    sign;
597 
598                 if (t->tm_isdst < 0)
599                     continue;
600 #ifdef TM_GMTOFF
601                 diff = t->TM_GMTOFF;
602 #else /* !defined TM_GMTOFF */
603                 /*
604                 ** C99 says that the UTC offset must
605                 ** be computed by looking only at
606                 ** tm_isdst. This requirement is
607                 ** incorrect, since it means the code
608                 ** must rely on magic (in this case
609                 ** altzone and timezone), and the
610                 ** magic might not have the correct
611                 ** offset. Doing things correctly is
612                 ** tricky and requires disobeying C99;
613                 ** see GNU C strftime for details.
614                 ** For now, punt and conform to the
615                 ** standard, even though it's incorrect.
616                 **
617                 ** C99 says that %z must be replaced by the
618                 ** empty string if the time zone is not
619                 ** determinable, so output nothing if the
620                 ** appropriate variables are not available.
621                 */
622                 if (t->tm_isdst == 0)
623 #ifdef USG_COMPAT
624                     diff = -timezone;
625 #else /* !defined USG_COMPAT */
626                     continue;
627 #endif /* !defined USG_COMPAT */
628                 else
629 #ifdef ALTZONE
630                     diff = -altzone;
631 #else /* !defined ALTZONE */
632                     continue;
633 #endif /* !defined ALTZONE */
634 #endif /* !defined TM_GMTOFF */
635                 if (diff < 0) {
636                     sign = "-";
637                     diff = -diff;
638                 } else  sign = "+";
639                 pt = _add(sign, pt, ptlim, modifier);
640                 diff /= SECSPERMIN;
641                 diff = (diff / MINSPERHOUR) * 100 +
642                     (diff % MINSPERHOUR);
643                 pt = _conv(diff,
644                                            getformat(modifier, "%04d",
645                                                      "%4d", "%d", "%04d"),
646                                            pt, ptlim);
647                 }
648                 continue;
649             case '+':
650                 pt = _fmt(locale->date_fmt, t, pt, ptlim,
651                     warnp, locale);
652                 continue;
653             case '%':
654             /*
655             ** X311J/88-090 (4.12.3.5): if conversion char is
656             ** undefined, behavior is undefined. Print out the
657             ** character itself as printf(3) also does.
658             */
659             default:
660                 break;
661             }
662         }
663         if (pt == ptlim)
664             break;
665         *pt++ = *format;
666     }
667     return pt;
668 }
669 
670 static char *
_conv(n,format,pt,ptlim)671 _conv(n, format, pt, ptlim)
672 const int       n;
673 const char * const  format;
674 char * const        pt;
675 const char * const  ptlim;
676 {
677     char    buf[INT_STRLEN_MAXIMUM(int) + 1];
678 
679     (void) snprintf(buf, sizeof(buf), format, n);
680     return _add(buf, pt, ptlim, 0);
681 }
682 
683 static char *
_add(str,pt,ptlim,modifier)684 _add(str, pt, ptlim, modifier)
685 const char *        str;
686 char *          pt;
687 const char * const  ptlim;
688 int                     modifier;
689 {
690         int c;
691 
692         switch (modifier) {
693         case FORCE_LOWER_CASE:
694                 while (pt < ptlim && (*pt = tolower(*str++)) != '\0') {
695                         ++pt;
696                 }
697                 break;
698 
699         case '^':
700                 while (pt < ptlim && (*pt = toupper(*str++)) != '\0') {
701                         ++pt;
702                 }
703                 break;
704 
705         case '#':
706                 while (pt < ptlim && (c = *str++) != '\0') {
707                         if (isupper(c)) {
708                                 c = tolower(c);
709                         } else if (islower(c)) {
710                                 c = toupper(c);
711                         }
712                         *pt = c;
713                         ++pt;
714                 }
715 
716                 break;
717 
718         default:
719                 while (pt < ptlim && (*pt = *str++) != '\0') {
720                         ++pt;
721                 }
722         }
723 
724     return pt;
725 }
726 
727 /*
728 ** POSIX and the C Standard are unclear or inconsistent about
729 ** what %C and %y do if the year is negative or exceeds 9999.
730 ** Use the convention that %C concatenated with %y yields the
731 ** same output as %Y, and that %Y contains at least 4 bytes,
732 ** with more only if necessary.
733 */
734 
735 static char *
_yconv(a,b,convert_top,convert_yy,pt,ptlim,modifier)736 _yconv(a, b, convert_top, convert_yy, pt, ptlim, modifier)
737 const int       a;
738 const int       b;
739 const int       convert_top;
740 const int       convert_yy;
741 char *          pt;
742 const char * const  ptlim;
743 int                     modifier;
744 {
745     register int    lead;
746     register int    trail;
747 
748 #define DIVISOR 100
749     trail = a % DIVISOR + b % DIVISOR;
750     lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
751     trail %= DIVISOR;
752     if (trail < 0 && lead > 0) {
753         trail += DIVISOR;
754         --lead;
755     } else if (lead < 0 && trail > 0) {
756         trail -= DIVISOR;
757         ++lead;
758     }
759     if (convert_top) {
760         if (lead == 0 && trail < 0)
761             pt = _add("-0", pt, ptlim, modifier);
762         else    pt = _conv(lead, getformat(modifier, "%02d",
763                                                    "%2d", "%d", "%02d"),
764                                    pt, ptlim);
765     }
766     if (convert_yy)
767         pt = _conv(((trail < 0) ? -trail : trail),
768                            getformat(modifier, "%02d", "%2d", "%d", "%02d"),
769                            pt, ptlim);
770     return pt;
771 }
772