string/strftime.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25 /*
  26  * Copyright (c) 1989, 1993
  27  *      The Regents of the University of California.  All rights reserved.
  28  *
  29  * Redistribution and use in source and binary forms, with or without
  30  * modification, are permitted provided that the following conditions
  31  * are met:
  32  * 1. Redistributions of source code must retain the above copyright
  33  *    notice, this list of conditions and the following disclaimer.
  34  * 2. Redistributions in binary form must reproduce the above copyright
  35  *    notice, this list of conditions and the following disclaimer in the
  36  *    documentation and/or other materials provided with the distribution.
  37  * 3. All advertising materials mentioning features or use of this software
  38  *    must display the following acknowledgement:
  39  *      This product includes software developed by the University of
  40  *      California, Berkeley and its contributors.
  41  * 4. Neither the name of the University nor the names of its contributors
  42  *    may be used to endorse or promote products derived from this software
  43  *    without specific prior written permission.
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  */
  57
  58
  59 #include <sys/types.h>
  60 #include <sys/time.h>
  61 #include <tzfile.h>
  62 #include <string.h>
  63
  64 static char *afmt[] = {
  65         "Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat",
  66 };
  67 static char *Afmt[] = {
  68         "Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday",
  69         "Saturday",
  70 };
  71 static char *bfmt[] = {
  72         "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep",
  73         "Oct", "Nov", "Dec",
  74 };
  75 static char *Bfmt[] = {
  76         "January", "February", "March", "April", "May", "June", "July",
  77         "August", "September", "October", "November", "December",
  78 };
  79
  80 static size_t gsize;
  81 static char *pt;
  82 static int _add __P((char *));
  83 static int _conv __P((int, int, int));
  84 static int _secs __P((const struct tm *));
  85 static size_t _fmt __P((const char *, const struct tm *));
  86
  87 size_t
  88 strftime(s, maxsize, format, t)
  89         char *s;
  90         size_t maxsize;
  91         const char *format;
  92         const struct tm *t;
  93 {
  94
  95         pt = s;
  96         if ((gsize = maxsize) < 1)
  97                 return(0);
  98         if (_fmt(format, t)) {
  99                 *pt = '\0';
 100                 return(maxsize - gsize);
 101         }
 102         return(0);
 103 }
 104
 105 static size_t
 106 _fmt(format, t)
 107         register const char *format;
 108         const struct tm *t;
 109 {
 110         for (; *format; ++format) {
 111                 if (*format == '%')
 112                         switch(*++format) {
 113                         case '\0':
 114                                 --format;
 115                                 break;
 116                         case 'A':
 117                                 if (t->tm_wday < 0 || t->tm_wday > 6)
 118                                         return(0);
 119                                 if (!_add(Afmt[t->tm_wday]))
 120                                         return(0);
 121                                 continue;
 122                         case 'a':
 123                                 if (t->tm_wday < 0 || t->tm_wday > 6)
 124                                         return(0);
 125                                 if (!_add(afmt[t->tm_wday]))
 126                                         return(0);
 127                                 continue;
 128                         case 'B':
 129                                 if (t->tm_mon < 0 || t->tm_mon > 11)
 130                                         return(0);
 131                                 if (!_add(Bfmt[t->tm_mon]))
 132                                         return(0);
 133                                 continue;
 134                         case 'b':
 135                         case 'h':
 136                                 if (t->tm_mon < 0 || t->tm_mon > 11)
 137                                         return(0);
 138                                 if (!_add(bfmt[t->tm_mon]))
 139                                         return(0);
 140                                 continue;
 141                         case 'C':
 142                                 if (!_fmt("%a %b %e %H:%M:%S %Y", t))
 143                                         return(0);
 144                                 continue;
 145                         case 'c':
 146                                 if (!_fmt("%m/%d/%y %H:%M:%S", t))
 147                                         return(0);
 148                                 continue;
 149                         case 'D':
 150                                 if (!_fmt("%m/%d/%y", t))
 151                                         return(0);
 152                                 continue;
 153                         case 'd':
 154                                 if (!_conv(t->tm_mday, 2, '0'))
 155                                         return(0);
 156                                 continue;
 157                         case 'e':
 158                                 if (!_conv(t->tm_mday, 2, ' '))
 159                                         return(0);
 160                                 continue;
 161                         case 'H':
 162                                 if (!_conv(t->tm_hour, 2, '0'))
 163                                         return(0);
 164                                 continue;
 165                         case 'I':
 166                                 if (!_conv(t->tm_hour % 12 ?
 167                                     t->tm_hour % 12 : 12, 2, '0'))
 168                                         return(0);
 169                                 continue;
 170                         case 'j':
 171                                 if (!_conv(t->tm_yday + 1, 3, '0'))
 172                                         return(0);
 173                                 continue;
 174                         case 'k':
 175                                 if (!_conv(t->tm_hour, 2, ' '))
 176                                         return(0);
 177                                 continue;
 178                         case 'l':
 179                                 if (!_conv(t->tm_hour % 12 ?
 180                                     t->tm_hour % 12 : 12, 2, ' '))
 181                                         return(0);
 182                                 continue;
 183                         case 'M':
 184                                 if (!_conv(t->tm_min, 2, '0'))
 185                                         return(0);
 186                                 continue;
 187                         case 'm':
 188                                 if (!_conv(t->tm_mon + 1, 2, '0'))
 189                                         return(0);
 190                                 continue;
 191                         case 'n':
 192                                 if (!_add("\n"))
 193                                         return(0);
 194                                 continue;
 195                         case 'p':
 196                                 if (!_add(t->tm_hour >= 12 ? "PM" : "AM"))
 197                                         return(0);
 198                                 continue;
 199                         case 'R':
 200                                 if (!_fmt("%H:%M", t))
 201                                         return(0);
 202                                 continue;
 203                         case 'r':
 204                                 if (!_fmt("%I:%M:%S %p", t))
 205                                         return(0);
 206                                 continue;
 207                         case 'S':
 208                                 if (!_conv(t->tm_sec, 2, '0'))
 209                                         return(0);
 210                                 continue;
 211                         case 's':
 212                                 if (!_secs(t))
 213                                         return(0);
 214                                 continue;
 215                         case 'T':
 216                         case 'X':
 217                                 if (!_fmt("%H:%M:%S", t))
 218                                         return(0);
 219                                 continue;
 220                         case 't':
 221                                 if (!_add("\t"))
 222                                         return(0);
 223                                 continue;
 224                         case 'U':
 225                                 if (!_conv((t->tm_yday + 7 - t->tm_wday) / 7,
 226                                     2, '0'))
 227                                         return(0);
 228                                 continue;
 229                         case 'W':
 230                                 if (!_conv((t->tm_yday + 7 -
 231                                     (t->tm_wday ? (t->tm_wday - 1) : 6))
 232                                     / 7, 2, '0'))
 233                                         return(0);
 234                                 continue;
 235                         case 'w':
 236                                 if (!_conv(t->tm_wday, 1, '0'))
 237                                         return(0);
 238                                 continue;
 239                         case 'x':
 240                                 if (!_fmt("%m/%d/%y", t))
 241                                         return(0);
 242                                 continue;
 243                         case 'y':
 244                                 if (!_conv((t->tm_year + TM_YEAR_BASE)
 245                                     % 100, 2, '0'))
 246                                         return(0);
 247                                 continue;
 248                         case 'Y':
 249                                 if (!_conv(t->tm_year + TM_YEAR_BASE, 4, '0'))
 250                                         return(0);
 251                                 continue;
 252                         case 'Z':
 253                                 if (!t->tm_zone || !_add(t->tm_zone))
 254                                         return(0);
 255                                 continue;
 256                         case '%':
 257                         /*
 258                          * X311J/88-090 (4.12.3.5): if conversion char is
 259                          * undefined, behavior is undefined.  Print out the
 260                          * character itself as printf(3) does.
 261                          */
 262                         default:
 263                                 break;
 264                 }
 265                 if (!gsize--)
 266                         return(0);
 267                 *pt++ = *format;
 268         }
 269         return(gsize);
 270 }
 271
 272 static int
 273 _secs(t)
 274         const struct tm *t;
 275 {
 276         static char buf[15];
 277         register time_t s;
 278         register char *p;
 279         struct tm tmp;
 280
 281         /* Make a copy, mktime(3) modifies the tm struct. */
 282         tmp = *t;
 283         s = mktime(&tmp);
 284         for (p = buf + sizeof(buf) - 2; s > 0 && p > buf; s /= 10)
 285                 *p-- = s % 10 + '0';
 286         return(_add(++p));
 287 }
 288
 289 static int
 290 _conv(n, digits, pad)
 291         int n, digits, pad;
 292 {
 293         static char buf[10];
 294         register char *p;
 295
 296         for (p = buf + sizeof(buf) - 2; n > 0 && p > buf; n /= 10, --digits)
 297                 *p-- = n % 10 + '0';
 298         while (p > buf && digits-- > 0)
 299                 *p-- = pad;
 300         return(_add(++p));
 301 }
 302
 303 static int
 304 _add(str)
 305         register char *str;
 306 {
 307         for (;; ++pt, --gsize) {
 308                 if (!gsize)
 309                         return(0);
 310                 if (!(*pt = *str++))
 311                         return(1);
 312         }
 313 }