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 #ifdef HAVE_CONFIG_H
  34 #include <config.h>
  35 #endif
  36 #ifdef TEST_STRPFTIME
  37 #include "strpftime-test.h"
  38 #endif
  39 #include "roken.h"
  40
  41 RCSID("$Id$");
  42
  43 static const char *abb_weekdays[] = {
  44     "Sun",
  45     "Mon",
  46     "Tue",
  47     "Wed",
  48     "Thu",
  49     "Fri",
  50     "Sat",
  51 };
  52
  53 static const char *full_weekdays[] = {
  54     "Sunday",
  55     "Monday",
  56     "Tuesday",
  57     "Wednesday",
  58     "Thursday",
  59     "Friday",
  60     "Saturday",
  61 };
  62
  63 static const char *abb_month[] = {
  64     "Jan",
  65     "Feb",
  66     "Mar",
  67     "Apr",
  68     "May",
  69     "Jun",
  70     "Jul",
  71     "Aug",
  72     "Sep",
  73     "Oct",
  74     "Nov",
  75     "Dec"
  76 };
  77
  78 static const char *full_month[] = {
  79     "January",
  80     "February",
  81     "Mars",
  82     "April",
  83     "May",
  84     "June",
  85     "July",
  86     "August",
  87     "September",
  88     "October",
  89     "November",
  90     "December"
  91 };
  92
  93 static const char *ampm[] = {
  94     "AM",
  95     "PM"
  96 };
  97
  98 /*
  99  * Convert hour in [0, 24] to [12 1 - 11 12 1 - 11 12]
 100  */
 101
 102 static int
 103 hour_24to12 (int hour)
 104 {
 105     int ret = hour % 12;
 106
 107     if (ret == 0)
 108         ret = 12;
 109     return ret;
 110 }
 111
 112 /*
 113  * Return AM or PM for `hour'
 114  */
 115
 116 static const char *
 117 hour_to_ampm (int hour)
 118 {
 119     return ampm[hour / 12];
 120 }
 121
 122 /*
 123  * Return the week number of `tm' (Sunday being the first day of the week)
 124  * as [0, 53]
 125  */
 126
 127 static int
 128 week_number_sun (const struct tm *tm)
 129 {
 130     return (tm->tm_yday + 7 - (tm->tm_yday % 7 - tm->tm_wday + 7) % 7) / 7;
 131 }
 132
 133 /*
 134  * Return the week number of `tm' (Monday being the first day of the week)
 135  * as [0, 53]
 136  */
 137
 138 static int
 139 week_number_mon (const struct tm *tm)
 140 {
 141     int wday = (tm->tm_wday + 6) % 7;
 142
 143     return (tm->tm_yday + 7 - (tm->tm_yday % 7 - wday + 7) % 7) / 7;
 144 }
 145
 146 /*
 147  * Return the week number of `tm' (Monday being the first day of the
 148  * week) as [01, 53].  Week number one is the one that has four or more
 149  * days in that year.
 150  */
 151
 152 static int
 153 week_number_mon4 (const struct tm *tm)
 154 {
 155     int wday  = (tm->tm_wday + 6) % 7;
 156     int w1day = (wday - tm->tm_yday % 7 + 7) % 7;
 157     int ret;
 158
 159     ret = (tm->tm_yday + w1day) / 7;
 160     if (w1day >= 4)
 161         --ret;
 162     if (ret == -1)
 163         ret = 53;
 164     else
 165         ++ret;
 166     return ret;
 167 }
 168
 169 /*
 170  *
 171  */
 172
 173 size_t ROKEN_LIB_FUNCTION
 174 strftime (char *buf, size_t maxsize, const char *format,
 175           const struct tm *tm)
 176 {
 177     size_t n = 0;
 178     int ret;
 179
 180     while (*format != '\0' && n < maxsize) {
 181         if (*format == '%') {
 182             ++format;
 183             if(*format == 'E' || *format == 'O')
 184                 ++format;
 185             switch (*format) {
 186             case 'a' :
 187                 ret = snprintf (buf, maxsize - n,
 188                                 "%s", abb_weekdays[tm->tm_wday]);
 189                 break;
 190             case 'A' :
 191                 ret = snprintf (buf, maxsize - n,
 192                                 "%s", full_weekdays[tm->tm_wday]);
 193                 break;
 194             case 'h' :
 195             case 'b' :
 196                 ret = snprintf (buf, maxsize - n,
 197                                 "%s", abb_month[tm->tm_mon]);
 198                 break;
 199             case 'B' :
 200                 ret = snprintf (buf, maxsize - n,
 201                                 "%s", full_month[tm->tm_mon]);
 202                 break;
 203             case 'c' :
 204                 ret = snprintf (buf, maxsize - n,
 205                                 "%d:%02d:%02d %02d:%02d:%02d",
 206                                 tm->tm_year,
 207                                 tm->tm_mon + 1,
 208                                 tm->tm_mday,
 209                                 tm->tm_hour,
 210                                 tm->tm_min,
 211                                 tm->tm_sec);
 212                 break;
 213             case 'C' :
 214                 ret = snprintf (buf, maxsize - n,
 215                                 "%02d", (tm->tm_year + 1900) / 100);
 216                 break;
 217             case 'd' :
 218                 ret = snprintf (buf, maxsize - n,
 219                                 "%02d", tm->tm_mday);
 220                 break;
 221             case 'D' :
 222                 ret = snprintf (buf, maxsize - n,
 223                                 "%02d/%02d/%02d",
 224                                 tm->tm_mon + 1,
 225                                 tm->tm_mday,
 226                                 (tm->tm_year + 1900) % 100);
 227                 break;
 228             case 'e' :
 229                 ret = snprintf (buf, maxsize - n,
 230                                 "%2d", tm->tm_mday);
 231                 break;
 232             case 'F':
 233                 ret = snprintf (buf, maxsize - n,
 234                                 "%04d-%02d-%02d", tm->tm_year + 1900,
 235                                 tm->tm_mon + 1, tm->tm_mday);
 236                 break;
 237             case 'g':
 238                 /* last two digits of week-based year */
 239                 abort();
 240             case 'G':
 241                 /* week-based year */
 242                 abort();
 243             case 'H' :
 244                 ret = snprintf (buf, maxsize - n,
 245                                 "%02d", tm->tm_hour);
 246                 break;
 247             case 'I' :
 248                 ret = snprintf (buf, maxsize - n,
 249                                 "%02d",
 250                                 hour_24to12 (tm->tm_hour));
 251                 break;
 252             case 'j' :
 253                 ret = snprintf (buf, maxsize - n,
 254                                 "%03d", tm->tm_yday + 1);
 255                 break;
 256             case 'k' :
 257                 ret = snprintf (buf, maxsize - n,
 258                                 "%2d", tm->tm_hour);
 259                 break;
 260             case 'l' :
 261                 ret = snprintf (buf, maxsize - n,
 262                                 "%2d",
 263                                 hour_24to12 (tm->tm_hour));
 264                 break;
 265             case 'm' :
 266                 ret = snprintf (buf, maxsize - n,
 267                                 "%02d", tm->tm_mon + 1);
 268                 break;
 269             case 'M' :
 270                 ret = snprintf (buf, maxsize - n,
 271                                 "%02d", tm->tm_min);
 272                 break;
 273             case 'n' :
 274                 ret = snprintf (buf, maxsize - n, "\n");
 275                 break;
 276             case 'p' :
 277                 ret = snprintf (buf, maxsize - n, "%s",
 278                                 hour_to_ampm (tm->tm_hour));
 279                 break;
 280             case 'r' :
 281                 ret = snprintf (buf, maxsize - n,
 282                                 "%02d:%02d:%02d %s",
 283                                 hour_24to12 (tm->tm_hour),
 284                                 tm->tm_min,
 285                                 tm->tm_sec,
 286                                 hour_to_ampm (tm->tm_hour));
 287                 break;
 288             case 'R' :
 289                 ret = snprintf (buf, maxsize - n,
 290                                 "%02d:%02d",
 291                                 tm->tm_hour,
 292                                 tm->tm_min);
 293
 294             case 's' :
 295                 ret = snprintf (buf, maxsize - n,
 296                                 "%d", (int)mktime(rk_UNCONST(tm)));
 297                 break;
 298             case 'S' :
 299                 ret = snprintf (buf, maxsize - n,
 300                                 "%02d", tm->tm_sec);
 301                 break;
 302             case 't' :
 303                 ret = snprintf (buf, maxsize - n, "\t");
 304                 break;
 305             case 'T' :
 306             case 'X' :
 307                 ret = snprintf (buf, maxsize - n,
 308                                 "%02d:%02d:%02d",
 309                                 tm->tm_hour,
 310                                 tm->tm_min,
 311                                 tm->tm_sec);
 312                 break;
 313             case 'u' :
 314                 ret = snprintf (buf, maxsize - n,
 315                                 "%d", (tm->tm_wday == 0) ? 7 : tm->tm_wday);
 316                 break;
 317             case 'U' :
 318                 ret = snprintf (buf, maxsize - n,
 319                                 "%02d", week_number_sun (tm));
 320                 break;
 321             case 'V' :
 322                 ret = snprintf (buf, maxsize - n,
 323                                 "%02d", week_number_mon4 (tm));
 324                 break;
 325             case 'w' :
 326                 ret = snprintf (buf, maxsize - n,
 327                                 "%d", tm->tm_wday);
 328                 break;
 329             case 'W' :
 330                 ret = snprintf (buf, maxsize - n,
 331                                 "%02d", week_number_mon (tm));
 332                 break;
 333             case 'x' :
 334                 ret = snprintf (buf, maxsize - n,
 335                                 "%d:%02d:%02d",
 336                                 tm->tm_year,
 337                                 tm->tm_mon + 1,
 338                                 tm->tm_mday);
 339                 break;
 340             case 'y' :
 341                 ret = snprintf (buf, maxsize - n,
 342                                 "%02d", (tm->tm_year + 1900) % 100);
 343                 break;
 344             case 'Y' :
 345                 ret = snprintf (buf, maxsize - n,
 346                                 "%d", tm->tm_year + 1900);
 347                 break;
 348             case 'z':
 349                 ret = snprintf (buf, maxsize - n,
 350                                 "%ld",
 351 #if defined(HAVE_STRUCT_TM_TM_GMTOFF)
 352                                 (long)tm->tm_gmtoff
 353 #elif defined(HAVE_TIMEZONE)
 354 #ifdef HAVE_ALTZONE
 355                                 tm->tm_isdst ?
 356                                 (long)altzone :
 357 #endif
 358                                 (long)timezone
 359 #else
 360 #error Where in timezone chaos are you?
 361 #endif
 362                                 );
 363                 break;
 364             case 'Z' :
 365                 ret = snprintf (buf, maxsize - n,
 366                                 "%s",
 367
 368 #if defined(HAVE_STRUCT_TM_TM_ZONE)
 369                                 tm->tm_zone
 370 #elif defined(HAVE_TIMEZONE)
 371                                 tzname[tm->tm_isdst]
 372 #else
 373 #error what?
 374 #endif
 375                     );
 376                 break;
 377             case '\0' :
 378                 --format;
 379                 /* FALLTHROUGH */
 380             case '%' :
 381                 ret = snprintf (buf, maxsize - n,
 382                                 "%%");
 383                 break;
 384             default :
 385                 ret = snprintf (buf, maxsize - n,
 386                                 "%%%c", *format);
 387                 break;
 388             }
 389             if (ret < 0 || ret >= maxsize - n)
 390                 return 0;
 391             n   += ret;
 392             buf += ret;
 393             ++format;
 394         } else {
 395             *buf++ = *format++;
 396             ++n;
 397         }
 398     }
 399     *buf++ = '\0';
 400     return n;
 401 }