granicus.if.org Git - postgresql/blob - src/timezone/strftime.c

   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 the above copyright notice and this paragraph are
   7  * duplicated in all such forms and that any documentation,
   8  * advertising materials, and other materials related to such
   9  * distribution and use acknowledge that the software was developed
  10  * by the University of California, Berkeley. The name of the
  11  * University may not be used to endorse or promote products derived
  12  * from this software without specific prior written permission.
  13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
  15  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
  16  *
  17  * IDENTIFICATION
  18  *        $PostgreSQL: pgsql/src/timezone/strftime.c,v 1.14 2009/06/11 14:49:15 momjian Exp $
  19  */
  20
  21 #include "postgres.h"
  22
  23 #include <fcntl.h>
  24 #include <locale.h>
  25
  26 #include "private.h"
  27 #include "tzfile.h"
  28
  29
  30 struct lc_time_T
  31 {
  32         const char *mon[MONSPERYEAR];
  33         const char *month[MONSPERYEAR];
  34         const char *wday[DAYSPERWEEK];
  35         const char *weekday[DAYSPERWEEK];
  36         const char *X_fmt;
  37         const char *x_fmt;
  38         const char *c_fmt;
  39         const char *am;
  40         const char *pm;
  41         const char *date_fmt;
  42 };
  43
  44 #define Locale  (&C_time_locale)
  45
  46 static const struct lc_time_T C_time_locale = {
  47         {
  48                 "Jan", "Feb", "Mar", "Apr", "May", "Jun",
  49                 "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"
  50         }, {
  51                 "January", "February", "March", "April", "May", "June",
  52                 "July", "August", "September", "October", "November", "December"
  53         }, {
  54                 "Sun", "Mon", "Tue", "Wed",
  55                 "Thu", "Fri", "Sat"
  56         }, {
  57                 "Sunday", "Monday", "Tuesday", "Wednesday",
  58                 "Thursday", "Friday", "Saturday"
  59         },
  60
  61         /* X_fmt */
  62         "%H:%M:%S",
  63
  64         /*
  65          * x_fmt
  66          *
  67          * C99 requires this format. Using just numbers (as here) makes Quakers
  68          * happier; it's also compatible with SVR4.
  69          */
  70         "%m/%d/%y",
  71
  72         /*
  73          * c_fmt
  74          *
  75          * C99 requires this format. Previously this code used "%D %X", but we now
  76          * conform to C99. Note that "%a %b %d %H:%M:%S %Y" is used by Solaris
  77          * 2.3.
  78          */
  79         "%a %b %e %T %Y",
  80
  81         /* am */
  82         "AM",
  83
  84         /* pm */
  85         "PM",
  86
  87         /* date_fmt */
  88         "%a %b %e %H:%M:%S %Z %Y"
  89 };
  90
  91 static char *_add(const char *, char *, const char *);
  92 static char *_conv(int, const char *, char *, const char *);
  93 static char *_fmt(const char *, const struct pg_tm *, char *,
  94          const char *, int *);
  95 static char *_yconv(const int, const int, const int, const int,
  96            char *, const char *const);
  97
  98 #define IN_NONE 0
  99 #define IN_SOME 1
 100 #define IN_THIS 2
 101 #define IN_ALL  3
 102
 103
 104 size_t
 105 pg_strftime(char *s, size_t maxsize, const char *format,
 106                         const struct pg_tm * t)
 107 {
 108         char       *p;
 109         int                     warn;
 110
 111         warn = IN_NONE;
 112         p = _fmt(((format == NULL) ? "%c" : format), t, s, s + maxsize, &warn);
 113         if (p == s + maxsize)
 114                 return 0;
 115         *p = '\0';
 116         return p - s;
 117 }
 118
 119 static char *
 120 _fmt(const char *format, const struct pg_tm * t, char *pt, const char *ptlim,
 121          int *warnp)
 122 {
 123         for (; *format; ++format)
 124         {
 125                 if (*format == '%')
 126                 {
 127         label:
 128                         switch (*++format)
 129                         {
 130                                 case '\0':
 131                                         --format;
 132                                         break;
 133                                 case 'A':
 134                                         pt = _add((t->tm_wday < 0 ||
 135                                                            t->tm_wday >= DAYSPERWEEK) ?
 136                                                           "?" : Locale->weekday[t->tm_wday],
 137                                                           pt, ptlim);
 138                                         continue;
 139                                 case 'a':
 140                                         pt = _add((t->tm_wday < 0 ||
 141                                                            t->tm_wday >= DAYSPERWEEK) ?
 142                                                           "?" : Locale->wday[t->tm_wday],
 143                                                           pt, ptlim);
 144                                         continue;
 145                                 case 'B':
 146                                         pt = _add((t->tm_mon < 0 ||
 147                                                            t->tm_mon >= MONSPERYEAR) ?
 148                                                           "?" : Locale->month[t->tm_mon],
 149                                                           pt, ptlim);
 150                                         continue;
 151                                 case 'b':
 152                                 case 'h':
 153                                         pt = _add((t->tm_mon < 0 ||
 154                                                            t->tm_mon >= MONSPERYEAR) ?
 155                                                           "?" : Locale->mon[t->tm_mon],
 156                                                           pt, ptlim);
 157                                         continue;
 158                                 case 'C':
 159
 160                                         /*
 161                                          * %C used to do a... _fmt("%a %b %e %X %Y", t);
 162                                          * ...whereas now POSIX 1003.2 calls for something
 163                                          * completely different. (ado, 1993-05-24)
 164                                          */
 165                                         pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 0,
 166                                                                 pt, ptlim);
 167                                         continue;
 168                                 case 'c':
 169                                         {
 170                                                 int                     warn2 = IN_SOME;
 171
 172                                                 pt = _fmt(Locale->c_fmt, t, pt, ptlim, warnp);
 173                                                 if (warn2 == IN_ALL)
 174                                                         warn2 = IN_THIS;
 175                                                 if (warn2 > *warnp)
 176                                                         *warnp = warn2;
 177                                         }
 178                                         continue;
 179                                 case 'D':
 180                                         pt = _fmt("%m/%d/%y", t, pt, ptlim, warnp);
 181                                         continue;
 182                                 case 'd':
 183                                         pt = _conv(t->tm_mday, "%02d", pt, ptlim);
 184                                         continue;
 185                                 case 'E':
 186                                 case 'O':
 187
 188                                         /*
 189                                          * C99 locale modifiers. The sequences  %Ec %EC %Ex %EX
 190                                          * %Ey %EY      %Od %oe %OH %OI %Om %OM  %OS %Ou %OU %OV %Ow
 191                                          * %OW %Oy are supposed to provide alternate
 192                                          * representations.
 193                                          */
 194                                         goto label;
 195                                 case 'e':
 196                                         pt = _conv(t->tm_mday, "%2d", pt, ptlim);
 197                                         continue;
 198                                 case 'F':
 199                                         pt = _fmt("%Y-%m-%d", t, pt, ptlim, warnp);
 200                                         continue;
 201                                 case 'H':
 202                                         pt = _conv(t->tm_hour, "%02d", pt, ptlim);
 203                                         continue;
 204                                 case 'I':
 205                                         pt = _conv((t->tm_hour % 12) ?
 206                                                            (t->tm_hour % 12) : 12,
 207                                                            "%02d", pt, ptlim);
 208                                         continue;
 209                                 case 'j':
 210                                         pt = _conv(t->tm_yday + 1, "%03d", pt, ptlim);
 211                                         continue;
 212                                 case 'k':
 213
 214                                         /*
 215                                          * This used to be...  _conv(t->tm_hour % 12 ? t->tm_hour
 216                                          * % 12 : 12, 2, ' '); ...and has been changed to the
 217                                          * below to match SunOS 4.1.1 and Arnold Robbins' strftime
 218                                          * version 3.0. That is, "%k" and "%l" have been swapped.
 219                                          * (ado, 1993-05-24)
 220                                          */
 221                                         pt = _conv(t->tm_hour, "%2d", pt, ptlim);
 222                                         continue;
 223 #ifdef KITCHEN_SINK
 224                                 case 'K':
 225
 226                                         /*
 227                                          * * After all this time, still unclaimed!
 228                                          */
 229                                         pt = _add("kitchen sink", pt, ptlim);
 230                                         continue;
 231 #endif   /* defined KITCHEN_SINK */
 232                                 case 'l':
 233
 234                                         /*
 235                                          * This used to be...  _conv(t->tm_hour, 2, ' '); ...and
 236                                          * has been changed to the below to match SunOS 4.1.1 and
 237                                          * Arnold Robbin's strftime version 3.0. That is, "%k" and
 238                                          * "%l" have been swapped. (ado, 1993-05-24)
 239                                          */
 240                                         pt = _conv((t->tm_hour % 12) ?
 241                                                            (t->tm_hour % 12) : 12,
 242                                                            "%2d", pt, ptlim);
 243                                         continue;
 244                                 case 'M':
 245                                         pt = _conv(t->tm_min, "%02d", pt, ptlim);
 246                                         continue;
 247                                 case 'm':
 248                                         pt = _conv(t->tm_mon + 1, "%02d", pt, ptlim);
 249                                         continue;
 250                                 case 'n':
 251                                         pt = _add("\n", pt, ptlim);
 252                                         continue;
 253                                 case 'p':
 254                                         pt = _add((t->tm_hour >= (HOURSPERDAY / 2)) ?
 255                                                           Locale->pm :
 256                                                           Locale->am,
 257                                                           pt, ptlim);
 258                                         continue;
 259                                 case 'R':
 260                                         pt = _fmt("%H:%M", t, pt, ptlim, warnp);
 261                                         continue;
 262                                 case 'r':
 263                                         pt = _fmt("%I:%M:%S %p", t, pt, ptlim, warnp);
 264                                         continue;
 265                                 case 'S':
 266                                         pt = _conv(t->tm_sec, "%02d", pt, ptlim);
 267                                         continue;
 268                                 case 'T':
 269                                         pt = _fmt("%H:%M:%S", t, pt, ptlim, warnp);
 270                                         continue;
 271                                 case 't':
 272                                         pt = _add("\t", pt, ptlim);
 273                                         continue;
 274                                 case 'U':
 275                                         pt = _conv((t->tm_yday + DAYSPERWEEK -
 276                                                                 t->tm_wday) / DAYSPERWEEK,
 277                                                            "%02d", pt, ptlim);
 278                                         continue;
 279                                 case 'u':
 280
 281                                         /*
 282                                          * From Arnold Robbins' strftime version 3.0: "ISO 8601:
 283                                          * Weekday as a decimal number [1 (Monday) - 7]" (ado,
 284                                          * 1993-05-24)
 285                                          */
 286                                         pt = _conv((t->tm_wday == 0) ?
 287                                                            DAYSPERWEEK : t->tm_wday,
 288                                                            "%d", pt, ptlim);
 289                                         continue;
 290                                 case 'V':               /* ISO 8601 week number */
 291                                 case 'G':               /* ISO 8601 year (four digits) */
 292                                 case 'g':               /* ISO 8601 year (two digits) */
 293 /*
 294  * From Arnold Robbins' strftime version 3.0: "the week number of the
 295  * year (the first Monday as the first day of week 1) as a decimal number
 296  * (01-53)."
 297  * (ado, 1993-05-24)
 298  *
 299  * From "http://www.ft.uni-erlangen.de/~mskuhn/iso-time.html" by Markus Kuhn:
 300  * "Week 01 of a year is per definition the first week which has the
 301  * Thursday in this year, which is equivalent to the week which contains
 302  * the fourth day of January. In other words, the first week of a new year
 303  * is the week which has the majority of its days in the new year. Week 01
 304  * might also contain days from the previous year and the week before week
 305  * 01 of a year is the last week (52 or 53) of the previous year even if
 306  * it contains days from the new year. A week starts with Monday (day 1)
 307  * and ends with Sunday (day 7). For example, the first week of the year
 308  * 1997 lasts from 1996-12-30 to 1997-01-05..."
 309  * (ado, 1996-01-02)
 310  */
 311                                         {
 312                                                 int                     year;
 313                                                 int                     base;
 314                                                 int                     yday;
 315                                                 int                     wday;
 316                                                 int                     w;
 317
 318                                                 year = t->tm_year;
 319                                                 base = TM_YEAR_BASE;
 320                                                 yday = t->tm_yday;
 321                                                 wday = t->tm_wday;
 322                                                 for (;;)
 323                                                 {
 324                                                         int                     len;
 325                                                         int                     bot;
 326                                                         int                     top;
 327
 328                                                         len = isleap_sum(year, base) ?
 329                                                                 DAYSPERLYEAR :
 330                                                                 DAYSPERNYEAR;
 331
 332                                                         /*
 333                                                          * What yday (-3 ... 3) does the ISO year begin
 334                                                          * on?
 335                                                          */
 336                                                         bot = ((yday + 11 - wday) %
 337                                                                    DAYSPERWEEK) - 3;
 338
 339                                                         /*
 340                                                          * What yday does the NEXT ISO year begin on?
 341                                                          */
 342                                                         top = bot -
 343                                                                 (len % DAYSPERWEEK);
 344                                                         if (top < -3)
 345                                                                 top += DAYSPERWEEK;
 346                                                         top += len;
 347                                                         if (yday >= top)
 348                                                         {
 349                                                                 ++base;
 350                                                                 w = 1;
 351                                                                 break;
 352                                                         }
 353                                                         if (yday >= bot)
 354                                                         {
 355                                                                 w = 1 + ((yday - bot) /
 356                                                                                  DAYSPERWEEK);
 357                                                                 break;
 358                                                         }
 359                                                         --base;
 360                                                         yday += isleap_sum(year, base) ?
 361                                                                 DAYSPERLYEAR :
 362                                                                 DAYSPERNYEAR;
 363                                                 }
 364                                                 if (*format == 'V')
 365                                                         pt = _conv(w, "%02d",
 366                                                                            pt, ptlim);
 367                                                 else if (*format == 'g')
 368                                                 {
 369                                                         *warnp = IN_ALL;
 370                                                         pt = _yconv(year, base, 0, 1,
 371                                                                                 pt, ptlim);
 372                                                 }
 373                                                 else
 374                                                         pt = _yconv(year, base, 1, 1,
 375                                                                                 pt, ptlim);
 376                                         }
 377                                         continue;
 378                                 case 'v':
 379
 380                                         /*
 381                                          * From Arnold Robbins' strftime version 3.0: "date as
 382                                          * dd-bbb-YYYY" (ado, 1993-05-24)
 383                                          */
 384                                         pt = _fmt("%e-%b-%Y", t, pt, ptlim, warnp);
 385                                         continue;
 386                                 case 'W':
 387                                         pt = _conv((t->tm_yday + DAYSPERWEEK -
 388                                                                 (t->tm_wday ?
 389                                                                  (t->tm_wday - 1) :
 390                                                                  (DAYSPERWEEK - 1))) / DAYSPERWEEK,
 391                                                            "%02d", pt, ptlim);
 392                                         continue;
 393                                 case 'w':
 394                                         pt = _conv(t->tm_wday, "%d", pt, ptlim);
 395                                         continue;
 396                                 case 'X':
 397                                         pt = _fmt(Locale->X_fmt, t, pt, ptlim, warnp);
 398                                         continue;
 399                                 case 'x':
 400                                         {
 401                                                 int                     warn2 = IN_SOME;
 402
 403                                                 pt = _fmt(Locale->x_fmt, t, pt, ptlim, &warn2);
 404                                                 if (warn2 == IN_ALL)
 405                                                         warn2 = IN_THIS;
 406                                                 if (warn2 > *warnp)
 407                                                         *warnp = warn2;
 408                                         }
 409                                         continue;
 410                                 case 'y':
 411                                         *warnp = IN_ALL;
 412                                         pt = _yconv(t->tm_year, TM_YEAR_BASE, 0, 1,
 413                                                                 pt, ptlim);
 414                                         continue;
 415                                 case 'Y':
 416                                         pt = _yconv(t->tm_year, TM_YEAR_BASE, 1, 1,
 417                                                                 pt, ptlim);
 418                                         continue;
 419                                 case 'Z':
 420                                         if (t->tm_zone != NULL)
 421                                                 pt = _add(t->tm_zone, pt, ptlim);
 422
 423                                         /*
 424                                          * C99 says that %Z must be replaced by the empty string
 425                                          * if the time zone is not determinable.
 426                                          */
 427                                         continue;
 428                                 case 'z':
 429                                         {
 430                                                 int                     diff;
 431                                                 char const *sign;
 432
 433                                                 if (t->tm_isdst < 0)
 434                                                         continue;
 435                                                 diff = t->tm_gmtoff;
 436                                                 if (diff < 0)
 437                                                 {
 438                                                         sign = "-";
 439                                                         diff = -diff;
 440                                                 }
 441                                                 else
 442                                                         sign = "+";
 443                                                 pt = _add(sign, pt, ptlim);
 444                                                 diff /= 60;
 445                                                 pt = _conv((diff / 60) * 100 + diff % 60,
 446                                                                    "%04d", pt, ptlim);
 447                                         }
 448                                         continue;
 449                                 case '+':
 450                                         pt = _fmt(Locale->date_fmt, t, pt, ptlim,
 451                                                           warnp);
 452                                         continue;
 453                                 case '%':
 454
 455                                         /*
 456                                          * X311J/88-090 (4.12.3.5): if conversion char is
 457                                          * undefined, behavior is undefined.  Print out the
 458                                          * character itself as printf(3) also does.
 459                                          */
 460                                 default:
 461                                         break;
 462                         }
 463                 }
 464                 if (pt == ptlim)
 465                         break;
 466                 *pt++ = *format;
 467         }
 468         return pt;
 469 }
 470
 471 static char *
 472 _conv(int n, const char *format, char *pt, const char *ptlim)
 473 {
 474         char            buf[INT_STRLEN_MAXIMUM(int) +1];
 475
 476         (void) sprintf(buf, format, n);
 477         return _add(buf, pt, ptlim);
 478 }
 479
 480 static char *
 481 _add(const char *str, char *pt, const char *ptlim)
 482 {
 483         while (pt < ptlim && (*pt = *str++) != '\0')
 484                 ++pt;
 485         return pt;
 486 }
 487
 488 /*
 489  * POSIX and the C Standard are unclear or inconsistent about
 490  * what %C and %y do if the year is negative or exceeds 9999.
 491  * Use the convention that %C concatenated with %y yields the
 492  * same output as %Y, and that %Y contains at least 4 bytes,
 493  * with more only if necessary.
 494  */
 495 static char *
 496 _yconv(const int a, const int b, const int convert_top,
 497            const int convert_yy, char *pt, const char *const ptlim)
 498 {
 499         int                     lead;
 500         int                     trail;
 501
 502 #define DIVISOR           100
 503         trail = a % DIVISOR + b % DIVISOR;
 504         lead = a / DIVISOR + b / DIVISOR + trail / DIVISOR;
 505         trail %= DIVISOR;
 506         if (trail < 0 && lead > 0)
 507         {
 508                 trail += DIVISOR;
 509                 --lead;
 510         }
 511         else if (lead < 0 && trail > 0)
 512         {
 513                 trail -= DIVISOR;
 514                 ++lead;
 515         }
 516         if (convert_top)
 517         {
 518                 if (lead == 0 && trail < 0)
 519                         pt = _add("-0", pt, ptlim);
 520                 else
 521                         pt = _conv(lead, "%02d", pt, ptlim);
 522         }
 523         if (convert_yy)
 524                 pt = _conv(((trail < 0) ? -trail : trail), "%02d", pt, ptlim);
 525         return pt;
 526 }