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   1 /*
   2  * Copyright (c) 1989 The Regents of the University of California.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms are permitted
   6  * provided that: (1) source distributions retain this entire copyright
   7  * notice and comment, and (2) distributions including binaries display
   8  * the following acknowledgement:  ``This product includes software
   9  * developed by the University of California, Berkeley and its contributors''
  10  * in the documentation or other materials provided with the distribution
  11  * and in all advertising materials mentioning features or use of this
  12  * software. Neither the name of the University nor the names of its
  13  * contributors may be used to endorse or promote products derived
  14  * from this software without specific prior written permission.
  15  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  17  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  18  */
  19
  20 #if defined(LIBC_SCCS) && !defined(lint)
  21 static char sccsid[] = "@(#)strftime.c  5.8 (Berkeley) 6/1/90";
  22 #endif /* LIBC_SCCS and not lint */
  23
  24 #include <sys/types.h>
  25 #include <sys/time.h>
  26 #include <tzfile.h>
  27 #include <string.h>
  28
  29 static char *afmt[] = {
  30         "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
  31 };
  32 static char *Afmt[] = {
  33         "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday",
  34         "Saturday",
  35 };
  36 static char *bfmt[] = {
  37         "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep",
  38         "Oct", "Nov", "Dec",
  39 };
  40 static char *Bfmt[] = {
  41         "January", "February", "March", "April", "May", "June", "July",
  42         "August", "September", "October", "November", "December",
  43 };
  44
  45 static size_t gsize;
  46 static char *pt;
  47
  48 size_t
  49 strftime(s, maxsize, format, t)
  50         char *s;
  51         char *format;
  52         size_t maxsize;
  53         struct tm *t;
  54 {
  55         size_t _fmt();
  56
  57         pt = s;
  58         if ((gsize = maxsize) < 1)
  59                 return(0);
  60         if (_fmt(format, t)) {
  61                 *pt = '\0';
  62                 return(maxsize - gsize);
  63         }
  64         return(0);
  65 }
  66
  67 static size_t
  68 _fmt(format, t)
  69         register char *format;
  70         struct tm *t;
  71 {
  72         for (; *format; ++format) {
  73                 if (*format == '%')
  74                         switch(*++format) {
  75                         case '\0':
  76                                 --format;
  77                                 break;
  78                         case 'A':
  79                                 if (t->tm_wday < 0 || t->tm_wday > 6)
  80                                         return(0);
  81                                 if (!_add(Afmt[t->tm_wday]))
  82                                         return(0);
  83                                 continue;
  84                         case 'a':
  85                                 if (t->tm_wday < 0 || t->tm_wday > 6)
  86                                         return(0);
  87                                 if (!_add(afmt[t->tm_wday]))
  88                                         return(0);
  89                                 continue;
  90                         case 'B':
  91                                 if (t->tm_mon < 0 || t->tm_mon > 11)
  92                                         return(0);
  93                                 if (!_add(Bfmt[t->tm_mon]))
  94                                         return(0);
  95                                 continue;
  96                         case 'b':
  97                         case 'h':
  98                                 if (t->tm_mon < 0 || t->tm_mon > 11)
  99                                         return(0);
 100                                 if (!_add(bfmt[t->tm_mon]))
 101                                         return(0);
 102                                 continue;
 103                         case 'C':
 104                                 if (!_fmt("%a %b %e %H:%M:%S %Y", t))
 105                                         return(0);
 106                                 continue;
 107                         case 'c':
 108                                 if (!_fmt("%m/%d/%y %H:%M:%S", t))
 109                                         return(0);
 110                                 continue;
 111                         case 'e':
 112                                 if (!_conv(t->tm_mday, 2, ' '))
 113                                         return(0);
 114                                 continue;
 115                         case 'D':
 116                                 if (!_fmt("%m/%d/%y", t))
 117                                         return(0);
 118                                 continue;
 119                         case 'd':
 120                                 if (!_conv(t->tm_mday, 2, '0'))
 121                                         return(0);
 122                                 continue;
 123                         case 'H':
 124                                 if (!_conv(t->tm_hour, 2, '0'))
 125                                         return(0);
 126                                 continue;
 127                         case 'I':
 128                                 if (!_conv(t->tm_hour % 12 ?
 129                                     t->tm_hour % 12 : 12, 2, '0'))
 130                                         return(0);
 131                                 continue;
 132                         case 'j':
 133                                 if (!_conv(t->tm_yday + 1, 3, '0'))
 134                                         return(0);
 135                                 continue;
 136                         case 'k':
 137                                 if (!_conv(t->tm_hour, 2, ' '))
 138                                         return(0);
 139                                 continue;
 140                         case 'l':
 141                                 if (!_conv(t->tm_hour % 12 ?
 142                                     t->tm_hour % 12 : 12, 2, ' '))
 143                                         return(0);
 144                                 continue;
 145                         case 'M':
 146                                 if (!_conv(t->tm_min, 2, '0'))
 147                                         return(0);
 148                                 continue;
 149                         case 'm':
 150                                 if (!_conv(t->tm_mon + 1, 2, '0'))
 151                                         return(0);
 152                                 continue;
 153                         case 'n':
 154                                 if (!_add("\n"))
 155                                         return(0);
 156                                 continue;
 157                         case 'p':
 158                                 if (!_add(t->tm_hour >= 12 ? "PM" : "AM"))
 159                                         return(0);
 160                                 continue;
 161                         case 'R':
 162                                 if (!_fmt("%H:%M", t))
 163                                         return(0);
 164                                 continue;
 165                         case 'r':
 166                                 if (!_fmt("%I:%M:%S %p", t))
 167                                         return(0);
 168                                 continue;
 169                         case 'S':
 170                                 if (!_conv(t->tm_sec, 2, '0'))
 171                                         return(0);
 172                                 continue;
 173                         case 'T':
 174                         case 'X':
 175                                 if (!_fmt("%H:%M:%S", t))
 176                                         return(0);
 177                                 continue;
 178                         case 't':
 179                                 if (!_add("\t"))
 180                                         return(0);
 181                                 continue;
 182                         case 'U':
 183                                 if (!_conv((t->tm_yday + 7 - t->tm_wday) / 7,
 184                                     2, '0'))
 185                                         return(0);
 186                                 continue;
 187                         case 'W':
 188                                 if (!_conv((t->tm_yday + 7 -
 189                                     (t->tm_wday ? (t->tm_wday - 1) : 6))
 190                                     / 7, 2, '0'))
 191                                         return(0);
 192                                 continue;
 193                         case 'w':
 194                                 if (!_conv(t->tm_wday, 1, '0'))
 195                                         return(0);
 196                                 continue;
 197                         case 'x':
 198                                 if (!_fmt("%m/%d/%y", t))
 199                                         return(0);
 200                                 continue;
 201                         case 'y':
 202                                 if (!_conv((t->tm_year + TM_YEAR_BASE)
 203                                     % 100, 2, '0'))
 204                                         return(0);
 205                                 continue;
 206                         case 'Y':
 207                                 if (!_conv(t->tm_year + TM_YEAR_BASE, 4, '0'))
 208                                         return(0);
 209                                 continue;
 210                         case 'Z':
 211                                 if (!t->tm_zone || !_add(t->tm_zone))
 212                                         return(0);
 213                                 continue;
 214                         case '%':
 215                         /*
 216                          * X311J/88-090 (4.12.3.5): if conversion char is
 217                          * undefined, behavior is undefined.  Print out the
 218                          * character itself as printf(3) does.
 219                          */
 220                         default:
 221                                 break;
 222                 }
 223                 if (!gsize--)
 224                         return(0);
 225                 *pt++ = *format;
 226         }
 227         return(gsize);
 228 }
 229
 230 static
 231 _conv(n, digits, pad)
 232         int n, digits;
 233         char pad;
 234 {
 235         static char buf[10];
 236         register char *p;
 237
 238         for (p = buf + sizeof(buf) - 2; n > 0 && p > buf; n /= 10, --digits)
 239                 *p-- = n % 10 + '0';
 240         while (p > buf && digits-- > 0)
 241                 *p-- = pad;
 242         return(_add(++p));
 243 }
 244
 245 static
 246 _add(str)
 247         register char *str;
 248 {
 249         for (;; ++pt, --gsize) {
 250                 if (!gsize)
 251                         return(0);
 252                 if (!(*pt = *str++))
 253                         return(1);
 254         }
 255 }