time/asctime.c

   1 /* Copyright (C) 1991, 1993, 1995, 1996, 1997 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include "../locale/localeinfo.h"
  20 #include <errno.h>
  21 #include <stdio.h>
  22 #include <time.h>
  23
  24 /* This is defined in locale/C-time.c in the GNU libc.  */
  25 extern const struct locale_data _nl_C_LC_TIME;
  26 #define ab_day_name (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (ABDAY_1)].string)
  27 #define ab_month_name (&_nl_C_LC_TIME.values[_NL_ITEM_INDEX (ABMON_1)].string)
  28
  29 static const char format[] = "%.3s %.3s%3d %.2d:%.2d:%.2d %d\n";
  30 static char result[              3+1+ 3+1+20+1+20+1+20+1+20+1+20+1 + 1];
  31
  32 /* Returns a string of the form "Day Mon dd hh:mm:ss yyyy\n"
  33    which is the representation of TP in that form.  */
  34 char *
  35 asctime (const struct tm *tp)
  36 {
  37   return __asctime_r (tp, result);
  38 }
  39
  40
  41 char *
  42 __asctime_r (const struct tm *tp, char *buf)
  43 {
  44   if (tp == NULL)
  45     {
  46       __set_errno (EINVAL);
  47       return NULL;
  48     }
  49
  50   if (sprintf (buf, format,
  51                (tp->tm_wday < 0 || tp->tm_wday >= 7 ?
  52                 "???" : ab_day_name[tp->tm_wday]),
  53                (tp->tm_mon < 0 || tp->tm_mon >= 12 ?
  54                 "???" : ab_month_name[tp->tm_mon]),
  55                tp->tm_mday, tp->tm_hour, tp->tm_min,
  56                tp->tm_sec, 1900 + tp->tm_year) < 0)
  57     return NULL;
  58
  59   return buf;
  60 }
  61 weak_alias (__asctime_r, asctime_r)