time/strftime_l.c

   1 /* Copyright (C) 2002-2018 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #ifdef HAVE_CONFIG_H
  19 # include <config.h>
  20 #endif
  21
  22 #ifdef _LIBC
  23 # define USE_IN_EXTENDED_LOCALE_MODEL 1
  24 # define HAVE_LIMITS_H 1
  25 # define HAVE_MBLEN 1
  26 # define HAVE_MBRLEN 1
  27 # define HAVE_STRUCT_ERA_ENTRY 1
  28 # define HAVE_TM_GMTOFF 1
  29 # define HAVE_TM_ZONE 1
  30 # define HAVE_TZNAME 1
  31 # define HAVE_TZSET 1
  32 # define HAVE_STRFTIME 0
  33 # define MULTIBYTE_IS_FORMAT_SAFE 1
  34 # define STDC_HEADERS 1
  35 # include "../locale/localeinfo.h"
  36 #endif
  37
  38 #if defined emacs && !defined HAVE_BCOPY
  39 # define HAVE_MEMCPY 1
  40 #endif
  41
  42 #include <ctype.h>
  43 #include <sys/types.h>          /* Some systems define `time_t' here.  */
  44
  45 #ifdef TIME_WITH_SYS_TIME
  46 # include <sys/time.h>
  47 # include <time.h>
  48 #else
  49 # ifdef HAVE_SYS_TIME_H
  50 #  include <sys/time.h>
  51 # else
  52 #  include <time.h>
  53 # endif
  54 #endif
  55 #if HAVE_TZNAME
  56 extern char *tzname[];
  57 #endif
  58
  59 /* Do multibyte processing if multibytes are supported, unless
  60    multibyte sequences are safe in formats.  Multibyte sequences are
  61    safe if they cannot contain byte sequences that look like format
  62    conversion specifications.  The GNU C Library uses UTF8 multibyte
  63    encoding, which is safe for formats, but strftime.c can be used
  64    with other C libraries that use unsafe encodings.  */
  65 #define DO_MULTIBYTE (HAVE_MBLEN && ! MULTIBYTE_IS_FORMAT_SAFE)
  66
  67 #if DO_MULTIBYTE
  68 # if HAVE_MBRLEN
  69 #  include <wchar.h>
  70 # else
  71    /* Simulate mbrlen with mblen as best we can.  */
  72 #  define mbstate_t int
  73 #  define mbrlen(s, n, ps) mblen (s, n)
  74 #  define mbsinit(ps) (*(ps) == 0)
  75 # endif
  76   static const mbstate_t mbstate_zero;
  77 #endif
  78
  79 #if HAVE_LIMITS_H
  80 # include <limits.h>
  81 #endif
  82
  83 #if STDC_HEADERS
  84 # include <stddef.h>
  85 # include <stdlib.h>
  86 # include <string.h>
  87 # include <stdbool.h>
  88 #else
  89 # ifndef HAVE_MEMCPY
  90 #  define memcpy(d, s, n) bcopy ((s), (d), (n))
  91 # endif
  92 #endif
  93
  94 #ifdef COMPILE_WIDE
  95 # include <endian.h>
  96 # define CHAR_T wchar_t
  97 # define UCHAR_T unsigned int
  98 # define L_(Str) L##Str
  99 # define NLW(Sym) _NL_W##Sym
 100
 101 # define MEMCPY(d, s, n) __wmemcpy (d, s, n)
 102 # define STRLEN(s) __wcslen (s)
 103
 104 #else
 105 # define CHAR_T char
 106 # define UCHAR_T unsigned char
 107 # define L_(Str) Str
 108 # define NLW(Sym) Sym
 109 # define ABALTMON_1 _NL_ABALTMON_1
 110
 111 # if !defined STDC_HEADERS && !defined HAVE_MEMCPY
 112 #  define MEMCPY(d, s, n) bcopy ((s), (d), (n))
 113 # else
 114 #  define MEMCPY(d, s, n) memcpy ((d), (s), (n))
 115 # endif
 116 # define STRLEN(s) strlen (s)
 117
 118 # ifdef _LIBC
 119 #  define MEMPCPY(d, s, n) __mempcpy (d, s, n)
 120 # else
 121 #  ifndef HAVE_MEMPCPY
 122 #   define MEMPCPY(d, s, n) ((void *) ((char *) memcpy (d, s, n) + (n)))
 123 #  endif
 124 # endif
 125 #endif
 126
 127 #ifndef PTR
 128 # define PTR void *
 129 #endif
 130
 131 #ifndef CHAR_BIT
 132 # define CHAR_BIT 8
 133 #endif
 134
 135 #ifndef NULL
 136 # define NULL 0
 137 #endif
 138
 139 #define TYPE_SIGNED(t) ((t) -1 < 0)
 140
 141 /* Bound on length of the string representing an integer value of type t.
 142    Subtract one for the sign bit if t is signed;
 143    302 / 1000 is log10 (2) rounded up;
 144    add one for integer division truncation;
 145    add one more for a minus sign if t is signed.  */
 146 #define INT_STRLEN_BOUND(t) \
 147  ((sizeof (t) * CHAR_BIT - TYPE_SIGNED (t)) * 302 / 1000 + 1 + TYPE_SIGNED (t))
 148
 149 #define TM_YEAR_BASE 1900
 150
 151 #ifndef __isleap
 152 /* Nonzero if YEAR is a leap year (every 4 years,
 153    except every 100th isn't, and every 400th is).  */
 154 # define __isleap(year) \
 155   ((year) % 4 == 0 && ((year) % 100 != 0 || (year) % 400 == 0))
 156 #endif
 157
 158
 159 #ifdef _LIBC
 160 # define tzname __tzname
 161 # define tzset __tzset
 162 #endif
 163
 164 #if !HAVE_TM_GMTOFF
 165 /* Portable standalone applications should supply a "time_r.h" that
 166    declares a POSIX-compliant localtime_r, for the benefit of older
 167    implementations that lack localtime_r or have a nonstandard one.
 168    Similarly for gmtime_r.  See the gnulib time_r module for one way
 169    to implement this.  */
 170 # include "time_r.h"
 171 # undef __gmtime_r
 172 # undef __localtime_r
 173 # define __gmtime_r gmtime_r
 174 # define __localtime_r localtime_r
 175 #endif
 176
 177
 178 #if !defined memset && !defined HAVE_MEMSET && !defined _LIBC
 179 /* Some systems lack the `memset' function and we don't want to
 180    introduce additional dependencies.  */
 181 /* The SGI compiler reportedly barfs on the trailing null
 182    if we use a string constant as the initializer.  28 June 1997, rms.  */
 183 static const CHAR_T spaces[16] = /* "                " */
 184 {
 185   L_(' '),L_(' '),L_(' '),L_(' '),L_(' '),L_(' '),L_(' '),L_(' '),
 186   L_(' '),L_(' '),L_(' '),L_(' '),L_(' '),L_(' '),L_(' '),L_(' ')
 187 };
 188 static const CHAR_T zeroes[16] = /* "0000000000000000" */
 189 {
 190   L_('0'),L_('0'),L_('0'),L_('0'),L_('0'),L_('0'),L_('0'),L_('0'),
 191   L_('0'),L_('0'),L_('0'),L_('0'),L_('0'),L_('0'),L_('0'),L_('0')
 192 };
 193
 194 # define memset_space(P, Len) \
 195   do {                                                                        \
 196     int _len = (Len);                                                         \
 197                                                                               \
 198     do                                                                        \
 199       {                                                                       \
 200         int _this = _len > 16 ? 16 : _len;                                    \
 201         (P) = MEMPCPY ((P), spaces, _this * sizeof (CHAR_T));                 \
 202         _len -= _this;                                                        \
 203       }                                                                       \
 204     while (_len > 0);                                                         \
 205   } while (0)
 206
 207 # define memset_zero(P, Len) \
 208   do {                                                                        \
 209     int _len = (Len);                                                         \
 210                                                                               \
 211     do                                                                        \
 212       {                                                                       \
 213         int _this = _len > 16 ? 16 : _len;                                    \
 214         (P) = MEMPCPY ((P), zeroes, _this * sizeof (CHAR_T));                 \
 215         _len -= _this;                                                        \
 216       }                                                                       \
 217     while (_len > 0);                                                         \
 218   } while (0)
 219 #else
 220 # ifdef COMPILE_WIDE
 221 #  define memset_space(P, Len) (wmemset ((P), L' ', (Len)), (P) += (Len))
 222 #  define memset_zero(P, Len) (wmemset ((P), L'0', (Len)), (P) += (Len))
 223 # else
 224 #  define memset_space(P, Len) (memset ((P), ' ', (Len)), (P) += (Len))
 225 #  define memset_zero(P, Len) (memset ((P), '0', (Len)), (P) += (Len))
 226 # endif
 227 #endif
 228
 229 #define add(n, f)                                                             \
 230   do                                                                          \
 231     {                                                                         \
 232       int _n = (n);                                                           \
 233       int _delta = width - _n;                                                \
 234       int _incr = _n + (_delta > 0 ? _delta : 0);                             \
 235       if ((size_t) _incr >= maxsize - i)                                      \
 236         return 0;                                                             \
 237       if (p)                                                                  \
 238         {                                                                     \
 239           if (_delta > 0)                                                     \
 240             {                                                                 \
 241               if (pad == L_('0'))                                             \
 242                 memset_zero (p, _delta);                                      \
 243               else                                                            \
 244                 memset_space (p, _delta);                                     \
 245             }                                                                 \
 246           f;                                                                  \
 247           p += _n;                                                            \
 248         }                                                                     \
 249       i += _incr;                                                             \
 250     } while (0)
 251
 252 #define cpy(n, s) \
 253     add ((n),                                                                 \
 254          if (to_lowcase)                                                      \
 255            memcpy_lowcase (p, (s), _n LOCALE_ARG);                            \
 256          else if (to_uppcase)                                                 \
 257            memcpy_uppcase (p, (s), _n LOCALE_ARG);                            \
 258          else                                                                 \
 259            MEMCPY ((PTR) p, (const PTR) (s), _n))
 260
 261 #ifdef COMPILE_WIDE
 262 # ifndef USE_IN_EXTENDED_LOCALE_MODEL
 263 #  undef __mbsrtowcs_l
 264 #  define __mbsrtowcs_l(d, s, l, st, loc) __mbsrtowcs (d, s, l, st)
 265 # endif
 266 # define widen(os, ws, l) \
 267   {                                                                           \
 268     mbstate_t __st;                                                           \
 269     const char *__s = os;                                                     \
 270     memset (&__st, '\0', sizeof (__st));                                      \
 271     l = __mbsrtowcs_l (NULL, &__s, 0, &__st, loc);                            \
 272     ws = alloca ((l + 1) * sizeof (wchar_t));                                 \
 273     (void) __mbsrtowcs_l (ws, &__s, l, &__st, loc);                           \
 274   }
 275 #endif
 276
 277
 278 #if defined _LIBC && defined USE_IN_EXTENDED_LOCALE_MODEL
 279 /* We use this code also for the extended locale handling where the
 280    function gets as an additional argument the locale which has to be
 281    used.  To access the values we have to redefine the _NL_CURRENT
 282    macro.  */
 283 # define strftime               __strftime_l
 284 # define wcsftime               __wcsftime_l
 285 # undef _NL_CURRENT
 286 # define _NL_CURRENT(category, item) \
 287   (current->values[_NL_ITEM_INDEX (item)].string)
 288 # define LOCALE_PARAM , locale_t loc
 289 # define LOCALE_ARG , loc
 290 # define HELPER_LOCALE_ARG  , current
 291 #else
 292 # define LOCALE_PARAM
 293 # define LOCALE_ARG
 294 # ifdef _LIBC
 295 #  define HELPER_LOCALE_ARG , _NL_CURRENT_DATA (LC_TIME)
 296 # else
 297 #  define HELPER_LOCALE_ARG
 298 # endif
 299 #endif
 300
 301 #ifdef COMPILE_WIDE
 302 # ifdef USE_IN_EXTENDED_LOCALE_MODEL
 303 #  define TOUPPER(Ch, L) __towupper_l (Ch, L)
 304 #  define TOLOWER(Ch, L) __towlower_l (Ch, L)
 305 # else
 306 #  define TOUPPER(Ch, L) towupper (Ch)
 307 #  define TOLOWER(Ch, L) towlower (Ch)
 308 # endif
 309 #else
 310 # ifdef _LIBC
 311 #  ifdef USE_IN_EXTENDED_LOCALE_MODEL
 312 #   define TOUPPER(Ch, L) __toupper_l (Ch, L)
 313 #   define TOLOWER(Ch, L) __tolower_l (Ch, L)
 314 #  else
 315 #   define TOUPPER(Ch, L) toupper (Ch)
 316 #   define TOLOWER(Ch, L) tolower (Ch)
 317 #  endif
 318 # else
 319 #  define TOUPPER(Ch, L) (islower (Ch) ? toupper (Ch) : (Ch))
 320 #  define TOLOWER(Ch, L) (isupper (Ch) ? tolower (Ch) : (Ch))
 321 # endif
 322 #endif
 323 /* We don't use `isdigit' here since the locale dependent
 324    interpretation is not what we want here.  We only need to accept
 325    the arabic digits in the ASCII range.  One day there is perhaps a
 326    more reliable way to accept other sets of digits.  */
 327 #define ISDIGIT(Ch) ((unsigned int) (Ch) - L_('0') <= 9)
 328
 329 static CHAR_T *memcpy_lowcase (CHAR_T *dest, const CHAR_T *src,
 330                                size_t len LOCALE_PARAM) __THROW;
 331
 332 static CHAR_T *
 333 memcpy_lowcase (CHAR_T *dest, const CHAR_T *src, size_t len LOCALE_PARAM)
 334 {
 335   while (len-- > 0)
 336     dest[len] = TOLOWER ((UCHAR_T) src[len], loc);
 337   return dest;
 338 }
 339
 340 static CHAR_T *memcpy_uppcase (CHAR_T *dest, const CHAR_T *src,
 341                                size_t len LOCALE_PARAM) __THROW;
 342
 343 static CHAR_T *
 344 memcpy_uppcase (CHAR_T *dest, const CHAR_T *src, size_t len LOCALE_PARAM)
 345 {
 346   while (len-- > 0)
 347     dest[len] = TOUPPER ((UCHAR_T) src[len], loc);
 348   return dest;
 349 }
 350
 351
 352 #if ! HAVE_TM_GMTOFF
 353 /* Yield the difference between *A and *B,
 354    measured in seconds, ignoring leap seconds.  */
 355 # define tm_diff ftime_tm_diff
 356 static int tm_diff (const struct tm *, const struct tm *) __THROW;
 357 static int
 358 tm_diff (const struct tm *a, const struct tm *b)
 359 {
 360   /* Compute intervening leap days correctly even if year is negative.
 361      Take care to avoid int overflow in leap day calculations,
 362      but it's OK to assume that A and B are close to each other.  */
 363   int a4 = (a->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (a->tm_year & 3);
 364   int b4 = (b->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (b->tm_year & 3);
 365   int a100 = a4 / 25 - (a4 % 25 < 0);
 366   int b100 = b4 / 25 - (b4 % 25 < 0);
 367   int a400 = a100 >> 2;
 368   int b400 = b100 >> 2;
 369   int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
 370   int years = a->tm_year - b->tm_year;
 371   int days = (365 * years + intervening_leap_days
 372               + (a->tm_yday - b->tm_yday));
 373   return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour))
 374                 + (a->tm_min - b->tm_min))
 375           + (a->tm_sec - b->tm_sec));
 376 }
 377 #endif /* ! HAVE_TM_GMTOFF */
 378
 379
 380
 381 /* The number of days from the first day of the first ISO week of this
 382    year to the year day YDAY with week day WDAY.  ISO weeks start on
 383    Monday; the first ISO week has the year's first Thursday.  YDAY may
 384    be as small as YDAY_MINIMUM.  */
 385 #define ISO_WEEK_START_WDAY 1 /* Monday */
 386 #define ISO_WEEK1_WDAY 4 /* Thursday */
 387 #define YDAY_MINIMUM (-366)
 388 static int iso_week_days (int, int) __THROW;
 389 #ifdef __GNUC__
 390 __inline__
 391 #endif
 392 static int
 393 iso_week_days (int yday, int wday)
 394 {
 395   /* Add enough to the first operand of % to make it nonnegative.  */
 396   int big_enough_multiple_of_7 = (-YDAY_MINIMUM / 7 + 2) * 7;
 397   return (yday
 398           - (yday - wday + ISO_WEEK1_WDAY + big_enough_multiple_of_7) % 7
 399           + ISO_WEEK1_WDAY - ISO_WEEK_START_WDAY);
 400 }
 401
 402
 403 #if !(defined _NL_CURRENT || HAVE_STRFTIME)
 404 static CHAR_T const weekday_name[][10] =
 405   {
 406     L_("Sunday"), L_("Monday"), L_("Tuesday"), L_("Wednesday"),
 407     L_("Thursday"), L_("Friday"), L_("Saturday")
 408   };
 409 static CHAR_T const month_name[][10] =
 410   {
 411     L_("January"), L_("February"), L_("March"), L_("April"), L_("May"),
 412     L_("June"), L_("July"), L_("August"), L_("September"), L_("October"),
 413     L_("November"), L_("December")
 414   };
 415 #endif
 416
 417
 418 #ifdef emacs
 419 # define my_strftime emacs_strftimeu
 420 # define ut_argument , ut
 421 # define ut_argument_spec , int ut
 422 #else
 423 # ifdef COMPILE_WIDE
 424 #  define my_strftime wcsftime
 425 #  define nl_get_alt_digit _nl_get_walt_digit
 426 # else
 427 #  define my_strftime strftime
 428 #  define nl_get_alt_digit _nl_get_alt_digit
 429 # endif
 430 # define ut_argument
 431 # define ut_argument_spec
 432 /* We don't have this information in general.  */
 433 # define ut 0
 434 #endif
 435
 436 static size_t __strftime_internal (CHAR_T *, size_t, const CHAR_T *,
 437                                    const struct tm *, bool *
 438                                    ut_argument_spec
 439                                    LOCALE_PARAM) __THROW;
 440
 441 /* Write information from TP into S according to the format
 442    string FORMAT, writing no more that MAXSIZE characters
 443    (including the terminating '\0') and returning number of
 444    characters written.  If S is NULL, nothing will be written
 445    anywhere, so to determine how many characters would be
 446    written, use NULL for S and (size_t) UINT_MAX for MAXSIZE.  */
 447
 448 size_t
 449 my_strftime (CHAR_T *s, size_t maxsize, const CHAR_T *format,
 450              const struct tm *tp ut_argument_spec LOCALE_PARAM)
 451 {
 452 #if !defined _LIBC && HAVE_TZNAME && HAVE_TZSET
 453   /* Solaris 2.5 tzset sometimes modifies the storage returned by localtime.
 454      Work around this bug by copying *tp before it might be munged.  */
 455   struct tm tmcopy;
 456   tmcopy = *tp;
 457   tp = &tmcopy;
 458 #endif
 459   bool tzset_called = false;
 460   return __strftime_internal (s, maxsize, format, tp, &tzset_called
 461                               ut_argument LOCALE_ARG);
 462 }
 463 #ifdef _LIBC
 464 libc_hidden_def (my_strftime)
 465 #endif
 466
 467 static size_t
 468 __strftime_internal (CHAR_T *s, size_t maxsize, const CHAR_T *format,
 469                      const struct tm *tp, bool *tzset_called
 470                      ut_argument_spec LOCALE_PARAM)
 471 {
 472 #if defined _LIBC && defined USE_IN_EXTENDED_LOCALE_MODEL
 473   struct __locale_data *const current = loc->__locales[LC_TIME];
 474 #endif
 475
 476   int hour12 = tp->tm_hour;
 477 #ifdef _NL_CURRENT
 478   /* We cannot make the following values variables since we must delay
 479      the evaluation of these values until really needed since some
 480      expressions might not be valid in every situation.  The `struct tm'
 481      might be generated by a strptime() call that initialized
 482      only a few elements.  Dereference the pointers only if the format
 483      requires this.  Then it is ok to fail if the pointers are invalid.  */
 484 # define a_wkday \
 485   ((const CHAR_T *) (tp->tm_wday < 0 || tp->tm_wday > 6                      \
 486                      ? "?" : _NL_CURRENT (LC_TIME, NLW(ABDAY_1) + tp->tm_wday)))
 487 # define f_wkday \
 488   ((const CHAR_T *) (tp->tm_wday < 0 || tp->tm_wday > 6                      \
 489                      ? "?" : _NL_CURRENT (LC_TIME, NLW(DAY_1) + tp->tm_wday)))
 490 # define a_month \
 491   ((const CHAR_T *) (tp->tm_mon < 0 || tp->tm_mon > 11                       \
 492                      ? "?" : _NL_CURRENT (LC_TIME, NLW(ABMON_1) + tp->tm_mon)))
 493 # define f_month \
 494   ((const CHAR_T *) (tp->tm_mon < 0 || tp->tm_mon > 11                       \
 495                      ? "?" : _NL_CURRENT (LC_TIME, NLW(MON_1) + tp->tm_mon)))
 496 # define a_altmonth \
 497   ((const CHAR_T *) (tp->tm_mon < 0 || tp->tm_mon > 11                       \
 498                      ? "?" : _NL_CURRENT (LC_TIME, NLW(ABALTMON_1) + tp->tm_mon)))
 499 # define f_altmonth \
 500   ((const CHAR_T *) (tp->tm_mon < 0 || tp->tm_mon > 11                       \
 501                      ? "?" : _NL_CURRENT (LC_TIME, NLW(ALTMON_1) + tp->tm_mon)))
 502 # define ampm \
 503   ((const CHAR_T *) _NL_CURRENT (LC_TIME, tp->tm_hour > 11                    \
 504                                  ? NLW(PM_STR) : NLW(AM_STR)))
 505
 506 # define aw_len STRLEN (a_wkday)
 507 # define am_len STRLEN (a_month)
 508 # define aam_len STRLEN (a_altmonth)
 509 # define ap_len STRLEN (ampm)
 510 #else
 511 # if !HAVE_STRFTIME
 512 #  define f_wkday (tp->tm_wday < 0 || tp->tm_wday > 6   \
 513                    ? "?" : weekday_name[tp->tm_wday])
 514 #  define f_month (tp->tm_mon < 0 || tp->tm_mon > 11    \
 515                    ? "?" : month_name[tp->tm_mon])
 516 #  define a_wkday f_wkday
 517 #  define a_month f_month
 518 #  define a_altmonth a_month
 519 #  define f_altmonth f_month
 520 #  define ampm (L_("AMPM") + 2 * (tp->tm_hour > 11))
 521
 522   size_t aw_len = 3;
 523   size_t am_len = 3;
 524   size_t aam_len = 3;
 525   size_t ap_len = 2;
 526 # endif
 527 #endif
 528   const char *zone;
 529   size_t i = 0;
 530   CHAR_T *p = s;
 531   const CHAR_T *f;
 532 #if DO_MULTIBYTE && !defined COMPILE_WIDE
 533   const char *format_end = NULL;
 534 #endif
 535
 536   zone = NULL;
 537 #if HAVE_TM_ZONE
 538   /* The POSIX test suite assumes that setting
 539      the environment variable TZ to a new value before calling strftime()
 540      will influence the result (the %Z format) even if the information in
 541      TP is computed with a totally different time zone.
 542      This is bogus: though POSIX allows bad behavior like this,
 543      POSIX does not require it.  Do the right thing instead.  */
 544   zone = (const char *) tp->tm_zone;
 545 #endif
 546 #if HAVE_TZNAME
 547   if (ut)
 548     {
 549       if (! (zone && *zone))
 550         zone = "GMT";
 551     }
 552 #endif
 553
 554   if (hour12 > 12)
 555     hour12 -= 12;
 556   else
 557     if (hour12 == 0)
 558       hour12 = 12;
 559
 560   for (f = format; *f != '\0'; ++f)
 561     {
 562       int pad = 0;              /* Padding for number ('-', '_', or 0).  */
 563       int modifier;             /* Field modifier ('E', 'O', or 0).  */
 564       int digits;               /* Max digits for numeric format.  */
 565       int number_value;         /* Numeric value to be printed.  */
 566       int negative_number;      /* 1 if the number is negative.  */
 567       const CHAR_T *subfmt;
 568       CHAR_T *bufp;
 569       CHAR_T buf[1 + (sizeof (int) < sizeof (time_t)
 570                       ? INT_STRLEN_BOUND (time_t)
 571                       : INT_STRLEN_BOUND (int))];
 572       int width = -1;
 573       int to_lowcase = 0;
 574       int to_uppcase = 0;
 575       int change_case = 0;
 576       int format_char;
 577
 578 #if DO_MULTIBYTE && !defined COMPILE_WIDE
 579       switch (*f)
 580         {
 581         case L_('%'):
 582           break;
 583
 584         case L_('\b'): case L_('\t'): case L_('\n'):
 585         case L_('\v'): case L_('\f'): case L_('\r'):
 586         case L_(' '): case L_('!'): case L_('"'): case L_('#'): case L_('&'):
 587         case L_('\''): case L_('('): case L_(')'): case L_('*'): case L_('+'):
 588         case L_(','): case L_('-'): case L_('.'): case L_('/'): case L_('0'):
 589         case L_('1'): case L_('2'): case L_('3'): case L_('4'): case L_('5'):
 590         case L_('6'): case L_('7'): case L_('8'): case L_('9'): case L_(':'):
 591         case L_(';'): case L_('<'): case L_('='): case L_('>'): case L_('?'):
 592         case L_('A'): case L_('B'): case L_('C'): case L_('D'): case L_('E'):
 593         case L_('F'): case L_('G'): case L_('H'): case L_('I'): case L_('J'):
 594         case L_('K'): case L_('L'): case L_('M'): case L_('N'): case L_('O'):
 595         case L_('P'): case L_('Q'): case L_('R'): case L_('S'): case L_('T'):
 596         case L_('U'): case L_('V'): case L_('W'): case L_('X'): case L_('Y'):
 597         case L_('Z'): case L_('['): case L_('\\'): case L_(']'): case L_('^'):
 598         case L_('_'): case L_('a'): case L_('b'): case L_('c'): case L_('d'):
 599         case L_('e'): case L_('f'): case L_('g'): case L_('h'): case L_('i'):
 600         case L_('j'): case L_('k'): case L_('l'): case L_('m'): case L_('n'):
 601         case L_('o'): case L_('p'): case L_('q'): case L_('r'): case L_('s'):
 602         case L_('t'): case L_('u'): case L_('v'): case L_('w'): case L_('x'):
 603         case L_('y'): case L_('z'): case L_('{'): case L_('|'): case L_('}'):
 604         case L_('~'):
 605           /* The C Standard requires these 98 characters (plus '%') to
 606              be in the basic execution character set.  None of these
 607              characters can start a multibyte sequence, so they need
 608              not be analyzed further.  */
 609           add (1, *p = *f);
 610           continue;
 611
 612         default:
 613           /* Copy this multibyte sequence until we reach its end, find
 614              an error, or come back to the initial shift state.  */
 615           {
 616             mbstate_t mbstate = mbstate_zero;
 617             size_t len = 0;
 618             size_t fsize;
 619
 620             if (! format_end)
 621               format_end = f + strlen (f) + 1;
 622             fsize = format_end - f;
 623
 624             do
 625               {
 626                 size_t bytes = mbrlen (f + len, fsize - len, &mbstate);
 627
 628                 if (bytes == 0)
 629                   break;
 630
 631                 if (bytes == (size_t) -2)
 632                   {
 633                     len += strlen (f + len);
 634                     break;
 635                   }
 636
 637                 if (bytes == (size_t) -1)
 638                   {
 639                     len++;
 640                     break;
 641                   }
 642
 643                 len += bytes;
 644               }
 645             while (! mbsinit (&mbstate));
 646
 647             cpy (len, f);
 648             f += len - 1;
 649             continue;
 650           }
 651         }
 652
 653 #else /* ! DO_MULTIBYTE */
 654
 655       /* Either multibyte encodings are not supported, they are
 656          safe for formats, so any non-'%' byte can be copied through,
 657          or this is the wide character version.  */
 658       if (*f != L_('%'))
 659         {
 660           add (1, *p = *f);
 661           continue;
 662         }
 663
 664 #endif /* ! DO_MULTIBYTE */
 665
 666       /* Check for flags that can modify a format.  */
 667       while (1)
 668         {
 669           switch (*++f)
 670             {
 671               /* This influences the number formats.  */
 672             case L_('_'):
 673             case L_('-'):
 674             case L_('0'):
 675               pad = *f;
 676               continue;
 677
 678               /* This changes textual output.  */
 679             case L_('^'):
 680               to_uppcase = 1;
 681               continue;
 682             case L_('#'):
 683               change_case = 1;
 684               continue;
 685
 686             default:
 687               break;
 688             }
 689           break;
 690         }
 691
 692       /* As a GNU extension we allow to specify the field width.  */
 693       if (ISDIGIT (*f))
 694         {
 695           width = 0;
 696           do
 697             {
 698               if (width > INT_MAX / 10
 699                   || (width == INT_MAX / 10 && *f - L_('0') > INT_MAX % 10))
 700                 /* Avoid overflow.  */
 701                 width = INT_MAX;
 702               else
 703                 {
 704                   width *= 10;
 705                   width += *f - L_('0');
 706                 }
 707               ++f;
 708             }
 709           while (ISDIGIT (*f));
 710         }
 711
 712       /* Check for modifiers.  */
 713       switch (*f)
 714         {
 715         case L_('E'):
 716         case L_('O'):
 717           modifier = *f++;
 718           break;
 719
 720         default:
 721           modifier = 0;
 722           break;
 723         }
 724
 725       /* Now do the specified format.  */
 726       format_char = *f;
 727       switch (format_char)
 728         {
 729 #define DO_NUMBER(d, v)                         \
 730           do                                    \
 731             {                                   \
 732               digits = d > width ? d : width;   \
 733               number_value = v;                 \
 734               goto do_number;                   \
 735             }                                   \
 736           while (0)
 737 #define DO_NUMBER_SPACEPAD(d, v)                \
 738           do                                    \
 739             {                                   \
 740               digits = d > width ? d : width;   \
 741               number_value = v;                 \
 742               goto do_number_spacepad;          \
 743             }                                   \
 744           while (0)
 745
 746         case L_('%'):
 747           if (modifier != 0)
 748             goto bad_format;
 749           add (1, *p = *f);
 750           break;
 751
 752         case L_('a'):
 753           if (modifier != 0)
 754             goto bad_format;
 755           if (change_case)
 756             {
 757               to_uppcase = 1;
 758               to_lowcase = 0;
 759             }
 760 #if defined _NL_CURRENT || !HAVE_STRFTIME
 761           cpy (aw_len, a_wkday);
 762           break;
 763 #else
 764           goto underlying_strftime;
 765 #endif
 766
 767         case 'A':
 768           if (modifier != 0)
 769             goto bad_format;
 770           if (change_case)
 771             {
 772               to_uppcase = 1;
 773               to_lowcase = 0;
 774             }
 775 #if defined _NL_CURRENT || !HAVE_STRFTIME
 776           cpy (STRLEN (f_wkday), f_wkday);
 777           break;
 778 #else
 779           goto underlying_strftime;
 780 #endif
 781
 782         case L_('b'):
 783         case L_('h'):
 784           if (change_case)
 785             {
 786               to_uppcase = 1;
 787               to_lowcase = 0;
 788             }
 789           if (modifier == L_('E'))
 790             goto bad_format;
 791 #if defined _NL_CURRENT || !HAVE_STRFTIME
 792           if (modifier == L_('O'))
 793             cpy (aam_len, a_altmonth);
 794           else
 795             cpy (am_len, a_month);
 796           break;
 797 #else
 798           goto underlying_strftime;
 799 #endif
 800
 801         case L_('B'):
 802           if (modifier == L_('E'))
 803             goto bad_format;
 804           if (change_case)
 805             {
 806               to_uppcase = 1;
 807               to_lowcase = 0;
 808             }
 809 #if defined _NL_CURRENT || !HAVE_STRFTIME
 810           if (modifier == L_('O'))
 811             cpy (STRLEN (f_altmonth), f_altmonth);
 812           else
 813             cpy (STRLEN (f_month), f_month);
 814           break;
 815 #else
 816           goto underlying_strftime;
 817 #endif
 818
 819         case L_('c'):
 820           if (modifier == L_('O'))
 821             goto bad_format;
 822 #ifdef _NL_CURRENT
 823           if (! (modifier == 'E'
 824                  && (*(subfmt =
 825                        (const CHAR_T *) _NL_CURRENT (LC_TIME,
 826                                                      NLW(ERA_D_T_FMT)))
 827                      != '\0')))
 828             subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(D_T_FMT));
 829 #else
 830 # if HAVE_STRFTIME
 831           goto underlying_strftime;
 832 # else
 833           subfmt = L_("%a %b %e %H:%M:%S %Y");
 834 # endif
 835 #endif
 836
 837         subformat:
 838           {
 839             CHAR_T *old_start = p;
 840             size_t len = __strftime_internal (NULL, (size_t) -1, subfmt,
 841                                               tp, tzset_called ut_argument
 842                                               LOCALE_ARG);
 843             add (len, __strftime_internal (p, maxsize - i, subfmt,
 844                                            tp, tzset_called ut_argument
 845                                            LOCALE_ARG));
 846
 847             if (to_uppcase)
 848               while (old_start < p)
 849                 {
 850                   *old_start = TOUPPER ((UCHAR_T) *old_start, loc);
 851                   ++old_start;
 852                 }
 853           }
 854           break;
 855
 856 #if HAVE_STRFTIME && ! (defined _NL_CURRENT && HAVE_STRUCT_ERA_ENTRY)
 857         underlying_strftime:
 858           {
 859             /* The relevant information is available only via the
 860                underlying strftime implementation, so use that.  */
 861             char ufmt[4];
 862             char *u = ufmt;
 863             char ubuf[1024]; /* enough for any single format in practice */
 864             size_t len;
 865             /* Make sure we're calling the actual underlying strftime.
 866                In some cases, config.h contains something like
 867                "#define strftime rpl_strftime".  */
 868 # ifdef strftime
 869 #  undef strftime
 870             size_t strftime ();
 871 # endif
 872
 873             *u++ = '%';
 874             if (modifier != 0)
 875               *u++ = modifier;
 876             *u++ = format_char;
 877             *u = '\0';
 878             len = strftime (ubuf, sizeof ubuf, ufmt, tp);
 879             if (len == 0 && ubuf[0] != '\0')
 880               return 0;
 881             cpy (len, ubuf);
 882           }
 883           break;
 884 #endif
 885
 886         case L_('C'):
 887           if (modifier == L_('E'))
 888             {
 889 #if HAVE_STRUCT_ERA_ENTRY
 890               struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
 891               if (era)
 892                 {
 893 # ifdef COMPILE_WIDE
 894                   size_t len = __wcslen (era->era_wname);
 895                   cpy (len, era->era_wname);
 896 # else
 897                   size_t len = strlen (era->era_name);
 898                   cpy (len, era->era_name);
 899 # endif
 900                   break;
 901                 }
 902 #else
 903 # if HAVE_STRFTIME
 904               goto underlying_strftime;
 905 # endif
 906 #endif
 907             }
 908
 909           {
 910             int year = tp->tm_year + TM_YEAR_BASE;
 911             DO_NUMBER (1, year / 100 - (year % 100 < 0));
 912           }
 913
 914         case L_('x'):
 915           if (modifier == L_('O'))
 916             goto bad_format;
 917 #ifdef _NL_CURRENT
 918           if (! (modifier == L_('E')
 919                  && (*(subfmt =
 920                        (const CHAR_T *)_NL_CURRENT (LC_TIME, NLW(ERA_D_FMT)))
 921                      != L_('\0'))))
 922             subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(D_FMT));
 923           goto subformat;
 924 #else
 925 # if HAVE_STRFTIME
 926           goto underlying_strftime;
 927 # else
 928           /* Fall through.  */
 929 # endif
 930 #endif
 931         case L_('D'):
 932           if (modifier != 0)
 933             goto bad_format;
 934           subfmt = L_("%m/%d/%y");
 935           goto subformat;
 936
 937         case L_('d'):
 938           if (modifier == L_('E'))
 939             goto bad_format;
 940
 941           DO_NUMBER (2, tp->tm_mday);
 942
 943         case L_('e'):
 944           if (modifier == L_('E'))
 945             goto bad_format;
 946
 947           DO_NUMBER_SPACEPAD (2, tp->tm_mday);
 948
 949           /* All numeric formats set DIGITS and NUMBER_VALUE and then
 950              jump to one of these two labels.  */
 951
 952         do_number_spacepad:
 953           /* Force `_' flag unless overwritten by `0' or '-' flag.  */
 954           if (pad != L_('0') && pad != L_('-'))
 955             pad = L_('_');
 956
 957         do_number:
 958           /* Format the number according to the MODIFIER flag.  */
 959
 960           if (modifier == L_('O') && 0 <= number_value)
 961             {
 962 #ifdef _NL_CURRENT
 963               /* Get the locale specific alternate representation of
 964                  the number NUMBER_VALUE.  If none exist NULL is returned.  */
 965               const CHAR_T *cp = nl_get_alt_digit (number_value
 966                                                    HELPER_LOCALE_ARG);
 967
 968               if (cp != NULL)
 969                 {
 970                   size_t digitlen = STRLEN (cp);
 971                   if (digitlen != 0)
 972                     {
 973                       cpy (digitlen, cp);
 974                       break;
 975                     }
 976                 }
 977 #else
 978 # if HAVE_STRFTIME
 979               goto underlying_strftime;
 980 # endif
 981 #endif
 982             }
 983           {
 984             unsigned int u = number_value;
 985
 986             bufp = buf + sizeof (buf) / sizeof (buf[0]);
 987             negative_number = number_value < 0;
 988
 989             if (negative_number)
 990               u = -u;
 991
 992             do
 993               *--bufp = u % 10 + L_('0');
 994             while ((u /= 10) != 0);
 995           }
 996
 997         do_number_sign_and_padding:
 998           if (negative_number)
 999             *--bufp = L_('-');
1000
1001           if (pad != L_('-'))
1002             {
1003               int padding = digits - (buf + (sizeof (buf) / sizeof (buf[0]))
1004                                       - bufp);
1005
1006               if (padding > 0)
1007                 {
1008                   if (pad == L_('_'))
1009                     {
1010                       if ((size_t) padding >= maxsize - i)
1011                         return 0;
1012
1013                       if (p)
1014                         memset_space (p, padding);
1015                       i += padding;
1016                       width = width > padding ? width - padding : 0;
1017                     }
1018                   else
1019                     {
1020                       if ((size_t) digits >= maxsize - i)
1021                         return 0;
1022
1023                       if (negative_number)
1024                         {
1025                           ++bufp;
1026
1027                           if (p)
1028                             *p++ = L_('-');
1029                           ++i;
1030                         }
1031
1032                       if (p)
1033                         memset_zero (p, padding);
1034                       i += padding;
1035                       width = 0;
1036                     }
1037                 }
1038             }
1039
1040           cpy (buf + sizeof (buf) / sizeof (buf[0]) - bufp, bufp);
1041           break;
1042
1043         case L_('F'):
1044           if (modifier != 0)
1045             goto bad_format;
1046           subfmt = L_("%Y-%m-%d");
1047           goto subformat;
1048
1049         case L_('H'):
1050           if (modifier == L_('E'))
1051             goto bad_format;
1052
1053           DO_NUMBER (2, tp->tm_hour);
1054
1055         case L_('I'):
1056           if (modifier == L_('E'))
1057             goto bad_format;
1058
1059           DO_NUMBER (2, hour12);
1060
1061         case L_('k'):           /* GNU extension.  */
1062           if (modifier == L_('E'))
1063             goto bad_format;
1064
1065           DO_NUMBER_SPACEPAD (2, tp->tm_hour);
1066
1067         case L_('l'):           /* GNU extension.  */
1068           if (modifier == L_('E'))
1069             goto bad_format;
1070
1071           DO_NUMBER_SPACEPAD (2, hour12);
1072
1073         case L_('j'):
1074           if (modifier == L_('E'))
1075             goto bad_format;
1076
1077           DO_NUMBER (3, 1 + tp->tm_yday);
1078
1079         case L_('M'):
1080           if (modifier == L_('E'))
1081             goto bad_format;
1082
1083           DO_NUMBER (2, tp->tm_min);
1084
1085         case L_('m'):
1086           if (modifier == L_('E'))
1087             goto bad_format;
1088
1089           DO_NUMBER (2, tp->tm_mon + 1);
1090
1091         case L_('n'):
1092           add (1, *p = L_('\n'));
1093           break;
1094
1095         case L_('P'):
1096           to_lowcase = 1;
1097 #if !defined _NL_CURRENT && HAVE_STRFTIME
1098           format_char = L_('p');
1099 #endif
1100           /* FALLTHROUGH */
1101
1102         case L_('p'):
1103           if (change_case)
1104             {
1105               to_uppcase = 0;
1106               to_lowcase = 1;
1107             }
1108 #if defined _NL_CURRENT || !HAVE_STRFTIME
1109           cpy (ap_len, ampm);
1110           break;
1111 #else
1112           goto underlying_strftime;
1113 #endif
1114
1115         case L_('R'):
1116           subfmt = L_("%H:%M");
1117           goto subformat;
1118
1119         case L_('r'):
1120 #if !defined _NL_CURRENT && HAVE_STRFTIME
1121           goto underlying_strftime;
1122 #else
1123 # ifdef _NL_CURRENT
1124           if (*(subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME,
1125                                                        NLW(T_FMT_AMPM)))
1126               == L_('\0'))
1127 # endif
1128             subfmt = L_("%I:%M:%S %p");
1129           goto subformat;
1130 #endif
1131
1132         case L_('S'):
1133           if (modifier == L_('E'))
1134             goto bad_format;
1135
1136           DO_NUMBER (2, tp->tm_sec);
1137
1138         case L_('s'):           /* GNU extension.  */
1139           {
1140             struct tm ltm;
1141             time_t t;
1142
1143             ltm = *tp;
1144             t = mktime (&ltm);
1145
1146             /* Generate string value for T using time_t arithmetic;
1147                this works even if sizeof (long) < sizeof (time_t).  */
1148
1149             bufp = buf + sizeof (buf) / sizeof (buf[0]);
1150             negative_number = t < 0;
1151
1152             do
1153               {
1154                 int d = t % 10;
1155                 t /= 10;
1156
1157                 if (negative_number)
1158                   {
1159                     d = -d;
1160
1161                     /* Adjust if division truncates to minus infinity.  */
1162                     if (0 < -1 % 10 && d < 0)
1163                       {
1164                         t++;
1165                         d += 10;
1166                       }
1167                   }
1168
1169                 *--bufp = d + L_('0');
1170               }
1171             while (t != 0);
1172
1173             digits = 1;
1174             goto do_number_sign_and_padding;
1175           }
1176
1177         case L_('X'):
1178           if (modifier == L_('O'))
1179             goto bad_format;
1180 #ifdef _NL_CURRENT
1181           if (! (modifier == L_('E')
1182                  && (*(subfmt =
1183                        (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(ERA_T_FMT)))
1184                      != L_('\0'))))
1185             subfmt = (const CHAR_T *) _NL_CURRENT (LC_TIME, NLW(T_FMT));
1186           goto subformat;
1187 #else
1188 # if HAVE_STRFTIME
1189           goto underlying_strftime;
1190 # else
1191           /* Fall through.  */
1192 # endif
1193 #endif
1194         case L_('T'):
1195           subfmt = L_("%H:%M:%S");
1196           goto subformat;
1197
1198         case L_('t'):
1199           add (1, *p = L_('\t'));
1200           break;
1201
1202         case L_('u'):
1203           DO_NUMBER (1, (tp->tm_wday - 1 + 7) % 7 + 1);
1204
1205         case L_('U'):
1206           if (modifier == L_('E'))
1207             goto bad_format;
1208
1209           DO_NUMBER (2, (tp->tm_yday - tp->tm_wday + 7) / 7);
1210
1211         case L_('V'):
1212         case L_('g'):
1213         case L_('G'):
1214           if (modifier == L_('E'))
1215             goto bad_format;
1216           {
1217             int year = tp->tm_year + TM_YEAR_BASE;
1218             int days = iso_week_days (tp->tm_yday, tp->tm_wday);
1219
1220             if (days < 0)
1221               {
1222                 /* This ISO week belongs to the previous year.  */
1223                 year--;
1224                 days = iso_week_days (tp->tm_yday + (365 + __isleap (year)),
1225                                       tp->tm_wday);
1226               }
1227             else
1228               {
1229                 int d = iso_week_days (tp->tm_yday - (365 + __isleap (year)),
1230                                        tp->tm_wday);
1231                 if (0 <= d)
1232                   {
1233                     /* This ISO week belongs to the next year.  */
1234                     year++;
1235                     days = d;
1236                   }
1237               }
1238
1239             switch (*f)
1240               {
1241               case L_('g'):
1242                 DO_NUMBER (2, (year % 100 + 100) % 100);
1243
1244               case L_('G'):
1245                 DO_NUMBER (1, year);
1246
1247               default:
1248                 DO_NUMBER (2, days / 7 + 1);
1249               }
1250           }
1251
1252         case L_('W'):
1253           if (modifier == L_('E'))
1254             goto bad_format;
1255
1256           DO_NUMBER (2, (tp->tm_yday - (tp->tm_wday - 1 + 7) % 7 + 7) / 7);
1257
1258         case L_('w'):
1259           if (modifier == L_('E'))
1260             goto bad_format;
1261
1262           DO_NUMBER (1, tp->tm_wday);
1263
1264         case L_('Y'):
1265           if (modifier == 'E')
1266             {
1267 #if HAVE_STRUCT_ERA_ENTRY
1268               struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
1269               if (era)
1270                 {
1271 # ifdef COMPILE_WIDE
1272                   subfmt = era->era_wformat;
1273 # else
1274                   subfmt = era->era_format;
1275 # endif
1276                   goto subformat;
1277                 }
1278 #else
1279 # if HAVE_STRFTIME
1280               goto underlying_strftime;
1281 # endif
1282 #endif
1283             }
1284           if (modifier == L_('O'))
1285             goto bad_format;
1286           else
1287             DO_NUMBER (1, tp->tm_year + TM_YEAR_BASE);
1288
1289         case L_('y'):
1290           if (modifier == L_('E'))
1291             {
1292 #if HAVE_STRUCT_ERA_ENTRY
1293               struct era_entry *era = _nl_get_era_entry (tp HELPER_LOCALE_ARG);
1294               if (era)
1295                 {
1296                   int delta = tp->tm_year - era->start_date[0];
1297                   DO_NUMBER (1, (era->offset
1298                                  + delta * era->absolute_direction));
1299                 }
1300 #else
1301 # if HAVE_STRFTIME
1302               goto underlying_strftime;
1303 # endif
1304 #endif
1305             }
1306           DO_NUMBER (2, (tp->tm_year % 100 + 100) % 100);
1307
1308         case L_('Z'):
1309           if (change_case)
1310             {
1311               to_uppcase = 0;
1312               to_lowcase = 1;
1313             }
1314
1315 #if HAVE_TZNAME
1316           /* The tzset() call might have changed the value.  */
1317           if (!(zone && *zone) && tp->tm_isdst >= 0)
1318             {
1319               /* POSIX.1 requires that local time zone information is used as
1320                  though strftime called tzset.  */
1321 # if HAVE_TZSET
1322               if (!*tzset_called)
1323                 {
1324                   tzset ();
1325                   *tzset_called = true;
1326                 }
1327 # endif
1328               zone = tp->tm_isdst <= 1 ? tzname[tp->tm_isdst] : "?";
1329             }
1330 #endif
1331           if (! zone)
1332             zone = "";
1333
1334 #ifdef COMPILE_WIDE
1335           {
1336             /* The zone string is always given in multibyte form.  We have
1337                to transform it first.  */
1338             wchar_t *wczone;
1339             size_t len;
1340             widen (zone, wczone, len);
1341             cpy (len, wczone);
1342           }
1343 #else
1344           cpy (strlen (zone), zone);
1345 #endif
1346           break;
1347
1348         case L_('z'):
1349           if (tp->tm_isdst < 0)
1350             break;
1351
1352           {
1353             int diff;
1354 #if HAVE_TM_GMTOFF
1355             diff = tp->tm_gmtoff;
1356 #else
1357             if (ut)
1358               diff = 0;
1359             else
1360               {
1361                 struct tm gtm;
1362                 struct tm ltm;
1363                 time_t lt;
1364
1365                 /* POSIX.1 requires that local time zone information is used as
1366                    though strftime called tzset.  */
1367 # if HAVE_TZSET
1368                 if (!*tzset_called)
1369                   {
1370                     tzset ();
1371                     *tzset_called = true;
1372                   }
1373 # endif
1374
1375                 ltm = *tp;
1376                 lt = mktime (&ltm);
1377
1378                 if (lt == (time_t) -1)
1379                   {
1380                     /* mktime returns -1 for errors, but -1 is also a
1381                        valid time_t value.  Check whether an error really
1382                        occurred.  */
1383                     struct tm tm;
1384
1385                     if (! __localtime_r (&lt, &tm)
1386                         || ((ltm.tm_sec ^ tm.tm_sec)
1387                             | (ltm.tm_min ^ tm.tm_min)
1388                             | (ltm.tm_hour ^ tm.tm_hour)
1389                             | (ltm.tm_mday ^ tm.tm_mday)
1390                             | (ltm.tm_mon ^ tm.tm_mon)
1391                             | (ltm.tm_year ^ tm.tm_year)))
1392                       break;
1393                   }
1394
1395                 if (! __gmtime_r (&lt, &gtm))
1396                   break;
1397
1398                 diff = tm_diff (&ltm, &gtm);
1399               }
1400 #endif
1401
1402             if (diff < 0)
1403               {
1404                 add (1, *p = L_('-'));
1405                 diff = -diff;
1406               }
1407             else
1408               add (1, *p = L_('+'));
1409
1410             diff /= 60;
1411             DO_NUMBER (4, (diff / 60) * 100 + diff % 60);
1412           }
1413
1414         case L_('\0'):          /* GNU extension: % at end of format.  */
1415             --f;
1416             /* Fall through.  */
1417         default:
1418           /* Unknown format; output the format, including the '%',
1419              since this is most likely the right thing to do if a
1420              multibyte string has been misparsed.  */
1421         bad_format:
1422           {
1423             int flen;
1424             for (flen = 1; f[1 - flen] != L_('%'); flen++)
1425               continue;
1426             cpy (flen, &f[1 - flen]);
1427           }
1428           break;
1429         }
1430     }
1431
1432   if (p && maxsize != 0)
1433     *p = L_('\0');
1434   return i;
1435 }
1436
1437
1438 #ifdef emacs
1439 /* For Emacs we have a separate interface which corresponds to the normal
1440    strftime function and does not have the extra information whether the
1441    TP arguments comes from a `gmtime' call or not.  */
1442 size_t
1443 emacs_strftime (char *s, size_t maxsize, const char *format,
1444                 const struct tm *tp)
1445 {
1446   return my_strftime (s, maxsize, format, tp, 0);
1447 }
1448 #endif
1449
1450 #if defined _LIBC && !defined COMPILE_WIDE
1451 weak_alias (__strftime_l, strftime_l)
1452 #endif