lib/roken/strftime.c

   1 /*
   2  * Copyright (c) 1999 - 2002 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of KTH nor the names of its contributors may be
  18  *    used to endorse or promote products derived from this software without
  19  *    specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY KTH AND ITS CONTRIBUTORS ``AS IS'' AND ANY
  22  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  24  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL KTH OR ITS CONTRIBUTORS BE
  25  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  26  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  27  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  28  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  29  * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  30  * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  31  * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */
  32
  33 #include <config.h>
  34 #include "roken.h"
  35 #ifdef TEST_STRPFTIME
  36 #include "strpftime-test.h"
  37 #endif
  38
  39 static const char *abb_weekdays[] = {
  40     "Sun",
  41     "Mon",
  42     "Tue",
  43     "Wed",
  44     "Thu",
  45     "Fri",
  46     "Sat",
  47 };
  48
  49 static const char *full_weekdays[] = {
  50     "Sunday",
  51     "Monday",
  52     "Tuesday",
  53     "Wednesday",
  54     "Thursday",
  55     "Friday",
  56     "Saturday",
  57 };
  58
  59 static const char *abb_month[] = {
  60     "Jan",
  61     "Feb",
  62     "Mar",
  63     "Apr",
  64     "May",
  65     "Jun",
  66     "Jul",
  67     "Aug",
  68     "Sep",
  69     "Oct",
  70     "Nov",
  71     "Dec"
  72 };
  73
  74 static const char *full_month[] = {
  75     "January",
  76     "February",
  77     "Mars",
  78     "April",
  79     "May",
  80     "June",
  81     "July",
  82     "August",
  83     "September",
  84     "October",
  85     "November",
  86     "December"
  87 };
  88
  89 static const char *ampm[] = {
  90     "AM",
  91     "PM"
  92 };
  93
  94 /*
  95  * Convert hour in [0, 24] to [12 1 - 11 12 1 - 11 12]
  96  */
  97
  98 static int
  99 hour_24to12 (int hour)
 100 {
 101     int ret = hour % 12;
 102
 103     if (ret == 0)
 104         ret = 12;
 105     return ret;
 106 }
 107
 108 /*
 109  * Return AM or PM for `hour'
 110  */
 111
 112 static const char *
 113 hour_to_ampm (int hour)
 114 {
 115     return ampm[hour / 12];
 116 }
 117
 118 /*
 119  * Return the week number of `tm' (Sunday being the first day of the week)
 120  * as [0, 53]
 121  */
 122
 123 static int
 124 week_number_sun (const struct tm *tm)
 125 {
 126     return (tm->tm_yday + 7 - (tm->tm_yday % 7 - tm->tm_wday + 7) % 7) / 7;
 127 }
 128
 129 /*
 130  * Return the week number of `tm' (Monday being the first day of the week)
 131  * as [0, 53]
 132  */
 133
 134 static int
 135 week_number_mon (const struct tm *tm)
 136 {
 137     int wday = (tm->tm_wday + 6) % 7;
 138
 139     return (tm->tm_yday + 7 - (tm->tm_yday % 7 - wday + 7) % 7) / 7;
 140 }
 141
 142 /*
 143  * Return the week number of `tm' (Monday being the first day of the
 144  * week) as [01, 53].  Week number one is the one that has four or more
 145  * days in that year.
 146  */
 147
 148 static int
 149 week_number_mon4 (const struct tm *tm)
 150 {
 151     int wday  = (tm->tm_wday + 6) % 7;
 152     int w1day = (wday - tm->tm_yday % 7 + 7) % 7;
 153     int ret;
 154
 155     ret = (tm->tm_yday + w1day) / 7;
 156     if (w1day >= 4)
 157         --ret;
 158     if (ret == -1)
 159         ret = 53;
 160     else
 161         ++ret;
 162     return ret;
 163 }
 164
 165 /*
 166  *
 167  */
 168
 169 ROKEN_LIB_FUNCTION size_t ROKEN_LIB_CALL
 170 strftime (char *buf, size_t maxsize, const char *format,
 171           const struct tm *tm)
 172 {
 173     size_t n = 0;
 174     int ret;
 175
 176     while (*format != '\0' && n < maxsize) {
 177         if (*format == '%') {
 178             ++format;
 179             if(*format == 'E' || *format == 'O')
 180                 ++format;
 181             switch (*format) {
 182             case 'a' :
 183                 ret = snprintf (buf, maxsize - n,
 184                                 "%s", abb_weekdays[tm->tm_wday]);
 185                 break;
 186             case 'A' :
 187                 ret = snprintf (buf, maxsize - n,
 188                                 "%s", full_weekdays[tm->tm_wday]);
 189                 break;
 190             case 'h' :
 191             case 'b' :
 192                 ret = snprintf (buf, maxsize - n,
 193                                 "%s", abb_month[tm->tm_mon]);
 194                 break;
 195             case 'B' :
 196                 ret = snprintf (buf, maxsize - n,
 197                                 "%s", full_month[tm->tm_mon]);
 198                 break;
 199             case 'c' :
 200                 ret = snprintf (buf, maxsize - n,
 201                                 "%d:%02d:%02d %02d:%02d:%02d",
 202                                 tm->tm_year,
 203                                 tm->tm_mon + 1,
 204                                 tm->tm_mday,
 205                                 tm->tm_hour,
 206                                 tm->tm_min,
 207                                 tm->tm_sec);
 208                 break;
 209             case 'C' :
 210                 ret = snprintf (buf, maxsize - n,
 211                                 "%02d", (tm->tm_year + 1900) / 100);
 212                 break;
 213             case 'd' :
 214                 ret = snprintf (buf, maxsize - n,
 215                                 "%02d", tm->tm_mday);
 216                 break;
 217             case 'D' :
 218                 ret = snprintf (buf, maxsize - n,
 219                                 "%02d/%02d/%02d",
 220                                 tm->tm_mon + 1,
 221                                 tm->tm_mday,
 222                                 (tm->tm_year + 1900) % 100);
 223                 break;
 224             case 'e' :
 225                 ret = snprintf (buf, maxsize - n,
 226                                 "%2d", tm->tm_mday);
 227                 break;
 228             case 'F':
 229                 ret = snprintf (buf, maxsize - n,
 230                                 "%04d-%02d-%02d", tm->tm_year + 1900,
 231                                 tm->tm_mon + 1, tm->tm_mday);
 232                 break;
 233             case 'g':
 234                 /* last two digits of week-based year */
 235                 abort();
 236             case 'G':
 237                 /* week-based year */
 238                 abort();
 239             case 'H' :
 240                 ret = snprintf (buf, maxsize - n,
 241                                 "%02d", tm->tm_hour);
 242                 break;
 243             case 'I' :
 244                 ret = snprintf (buf, maxsize - n,
 245                                 "%02d",
 246                                 hour_24to12 (tm->tm_hour));
 247                 break;
 248             case 'j' :
 249                 ret = snprintf (buf, maxsize - n,
 250                                 "%03d", tm->tm_yday + 1);
 251                 break;
 252             case 'k' :
 253                 ret = snprintf (buf, maxsize - n,
 254                                 "%2d", tm->tm_hour);
 255                 break;
 256             case 'l' :
 257                 ret = snprintf (buf, maxsize - n,
 258                                 "%2d",
 259                                 hour_24to12 (tm->tm_hour));
 260                 break;
 261             case 'm' :
 262                 ret = snprintf (buf, maxsize - n,
 263                                 "%02d", tm->tm_mon + 1);
 264                 break;
 265             case 'M' :
 266                 ret = snprintf (buf, maxsize - n,
 267                                 "%02d", tm->tm_min);
 268                 break;
 269             case 'n' :
 270                 ret = snprintf (buf, maxsize - n, "\n");
 271                 break;
 272             case 'p' :
 273                 ret = snprintf (buf, maxsize - n, "%s",
 274                                 hour_to_ampm (tm->tm_hour));
 275                 break;
 276             case 'r' :
 277                 ret = snprintf (buf, maxsize - n,
 278                                 "%02d:%02d:%02d %s",
 279                                 hour_24to12 (tm->tm_hour),
 280                                 tm->tm_min,
 281                                 tm->tm_sec,
 282                                 hour_to_ampm (tm->tm_hour));
 283                 break;
 284             case 'R' :
 285                 ret = snprintf (buf, maxsize - n,
 286                                 "%02d:%02d",
 287                                 tm->tm_hour,
 288                                 tm->tm_min);
 289
 290             case 's' :
 291                 ret = snprintf (buf, maxsize - n,
 292                                 "%d", (int)mktime(rk_UNCONST(tm)));
 293                 break;
 294             case 'S' :
 295                 ret = snprintf (buf, maxsize - n,
 296                                 "%02d", tm->tm_sec);
 297                 break;
 298             case 't' :
 299                 ret = snprintf (buf, maxsize - n, "\t");
 300                 break;
 301             case 'T' :
 302             case 'X' :
 303                 ret = snprintf (buf, maxsize - n,
 304                                 "%02d:%02d:%02d",
 305                                 tm->tm_hour,
 306                                 tm->tm_min,
 307                                 tm->tm_sec);
 308                 break;
 309             case 'u' :
 310                 ret = snprintf (buf, maxsize - n,
 311                                 "%d", (tm->tm_wday == 0) ? 7 : tm->tm_wday);
 312                 break;
 313             case 'U' :
 314                 ret = snprintf (buf, maxsize - n,
 315                                 "%02d", week_number_sun (tm));
 316                 break;
 317             case 'V' :
 318                 ret = snprintf (buf, maxsize - n,
 319                                 "%02d", week_number_mon4 (tm));
 320                 break;
 321             case 'w' :
 322                 ret = snprintf (buf, maxsize - n,
 323                                 "%d", tm->tm_wday);
 324                 break;
 325             case 'W' :
 326                 ret = snprintf (buf, maxsize - n,
 327                                 "%02d", week_number_mon (tm));
 328                 break;
 329             case 'x' :
 330                 ret = snprintf (buf, maxsize - n,
 331                                 "%d:%02d:%02d",
 332                                 tm->tm_year,
 333                                 tm->tm_mon + 1,
 334                                 tm->tm_mday);
 335                 break;
 336             case 'y' :
 337                 ret = snprintf (buf, maxsize - n,
 338                                 "%02d", (tm->tm_year + 1900) % 100);
 339                 break;
 340             case 'Y' :
 341                 ret = snprintf (buf, maxsize - n,
 342                                 "%d", tm->tm_year + 1900);
 343                 break;
 344             case 'z':
 345                 ret = snprintf (buf, maxsize - n,
 346                                 "%ld",
 347 #if defined(HAVE_STRUCT_TM_TM_GMTOFF)
 348                                 (long)tm->tm_gmtoff
 349 #elif defined(HAVE_TIMEZONE)
 350 #ifdef HAVE_ALTZONE
 351                                 tm->tm_isdst ?
 352                                 (long)altzone :
 353 #endif
 354                                 (long)timezone
 355 #else
 356 #error Where in timezone chaos are you?
 357 #endif
 358                                 );
 359                 break;
 360             case 'Z' :
 361                 ret = snprintf (buf, maxsize - n,
 362                                 "%s",
 363
 364 #if defined(HAVE_STRUCT_TM_TM_ZONE)
 365                                 tm->tm_zone
 366 #elif defined(HAVE_TIMEZONE)
 367                                 tzname[tm->tm_isdst]
 368 #else
 369 #error what?
 370 #endif
 371                     );
 372                 break;
 373             case '\0' :
 374                 --format;
 375                 /* FALLTHROUGH */
 376             case '%' :
 377                 ret = snprintf (buf, maxsize - n,
 378                                 "%%");
 379                 break;
 380             default :
 381                 ret = snprintf (buf, maxsize - n,
 382                                 "%%%c", *format);
 383                 break;
 384             }
 385             if (ret < 0 || ret >= (int)(maxsize - n))
 386                 return 0;
 387             n   += ret;
 388             buf += ret;
 389             ++format;
 390         } else {
 391             *buf++ = *format++;
 392             ++n;
 393         }
 394     }
 395     *buf++ = '\0';
 396     return n;
 397 }