root/ext/date/lib/parse_tz.c

DEFINITIONS

1. read_preamble
2. read_header
3. skip_64bit_transistions
4. read_transistions
5. skip_64bit_types
6. read_types
7. skip_posix_string
8. read_location
9. timelib_dump_tzinfo
10. seek_to_tz_position
11. timelib_builtin_db
12. timelib_timezone_builtin_identifiers_list
13. timelib_timezone_id_is_valid
14. skip_64bit_preamble
15. read_64bit_header
16. timelib_parse_tzfile
17. fetch_timezone_offset
18. fetch_leaptime_offset
19. timelib_timestamp_is_in_dst
20. timelib_get_time_zone_info
21. timelib_get_current_offset

   1 /*
   2  * The MIT License (MIT)
   3  *
   4  * Copyright (c) 2015 Derick Rethans
   5  *
   6  * Permission is hereby granted, free of charge, to any person obtaining a copy
   7  * of this software and associated documentation files (the "Software"), to deal
   8  * in the Software without restriction, including without limitation the rights
   9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  10  * copies of the Software, and to permit persons to whom the Software is
  11  * furnished to do so, subject to the following conditions:
  12  *
  13  * The above copyright notice and this permission notice shall be included in
  14  * all copies or substantial portions of the Software.
  15  *
  16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  19  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  22  * THE SOFTWARE.
  23  */
  24 
  25 #include "timelib.h"
  26 
  27 #include <stdio.h>
  28 
  29 #ifdef HAVE_LOCALE_H
  30 #include <locale.h>
  31 #endif
  32 
  33 #ifdef HAVE_STRING_H
  34 #include <string.h>
  35 #else
  36 #include <strings.h>
  37 #endif
  38 
  39 #define TIMELIB_SUPPORTS_V2DATA
  40 #include "timezonedb.h"
  41 
  42 #if (defined(__APPLE__) || defined(__APPLE_CC__)) && (defined(__BIG_ENDIAN__) || defined(__LITTLE_ENDIAN__))
  43 # if defined(__LITTLE_ENDIAN__)
  44 #  undef WORDS_BIGENDIAN
  45 # else
  46 #  if defined(__BIG_ENDIAN__)
  47 #   define WORDS_BIGENDIAN
  48 #  endif
  49 # endif
  50 #endif
  51 
  52 #ifdef WORDS_BIGENDIAN
  53 #define timelib_conv_int(l) (l)
  54 #else
  55 #define timelib_conv_int(l) ((l & 0x000000ff) << 24) + ((l & 0x0000ff00) << 8) + ((l & 0x00ff0000) >> 8) + ((l & 0xff000000) >> 24)
  56 #endif
  57 
  58 static int read_preamble(const unsigned char **tzf, timelib_tzinfo *tz)
  59 {
  60         uint32_t version;
  61 
  62         /* read ID */
  63         version = (*tzf)[3] - '0';
  64         *tzf += 4;
  65 
  66         /* read BC flag */
  67         tz->bc = (**tzf == '\1');
  68         *tzf += 1;
  69 
  70         /* read country code */
  71         memcpy(tz->location.country_code, *tzf, 2);
  72         tz->location.country_code[2] = '\0';
  73         *tzf += 2;
  74 
  75         /* skip rest of preamble */
  76         *tzf += 13;
  77 
  78         return version;
  79 }
  80 
  81 static void read_header(const unsigned char **tzf, timelib_tzinfo *tz)
  82 {
  83         uint32_t buffer[6];
  84 
  85         memcpy(&buffer, *tzf, sizeof(buffer));
  86         tz->bit32.ttisgmtcnt = timelib_conv_int(buffer[0]);
  87         tz->bit32.ttisstdcnt = timelib_conv_int(buffer[1]);
  88         tz->bit32.leapcnt    = timelib_conv_int(buffer[2]);
  89         tz->bit32.timecnt    = timelib_conv_int(buffer[3]);
  90         tz->bit32.typecnt    = timelib_conv_int(buffer[4]);
  91         tz->bit32.charcnt    = timelib_conv_int(buffer[5]);
  92         *tzf += sizeof(buffer);
  93 }
  94 
  95 static void skip_64bit_transistions(const unsigned char **tzf, timelib_tzinfo *tz)
  96 {
  97         if (tz->bit64.timecnt) {
  98                 *tzf += (sizeof(int64_t) * tz->bit64.timecnt);
  99                 *tzf += (sizeof(unsigned char) * tz->bit64.timecnt);
 100         }
 101 }
 102 
 103 static void read_transistions(const unsigned char **tzf, timelib_tzinfo *tz)
 104 {
 105         int32_t *buffer = NULL;
 106         uint32_t i;
 107         unsigned char *cbuffer = NULL;
 108 
 109         if (tz->bit32.timecnt) {
 110                 buffer = (int32_t*) timelib_malloc(tz->bit32.timecnt * sizeof(int32_t));
 111                 if (!buffer) {
 112                         return;
 113                 }
 114                 memcpy(buffer, *tzf, sizeof(int32_t) * tz->bit32.timecnt);
 115                 *tzf += (sizeof(int32_t) * tz->bit32.timecnt);
 116                 for (i = 0; i < tz->bit32.timecnt; i++) {
 117                         buffer[i] = timelib_conv_int(buffer[i]);
 118                 }
 119 
 120                 cbuffer = (unsigned char*) timelib_malloc(tz->bit32.timecnt * sizeof(unsigned char));
 121                 if (!cbuffer) {
 122                         timelib_free(buffer);
 123                         return;
 124                 }
 125                 memcpy(cbuffer, *tzf, sizeof(unsigned char) * tz->bit32.timecnt);
 126                 *tzf += sizeof(unsigned char) * tz->bit32.timecnt;
 127         }
 128 
 129         tz->trans = buffer;
 130         tz->trans_idx = cbuffer;
 131 }
 132 
 133 static void skip_64bit_types(const unsigned char **tzf, timelib_tzinfo *tz)
 134 {
 135         *tzf += sizeof(unsigned char) * 6 * tz->bit64.typecnt;
 136         *tzf += sizeof(char) * tz->bit64.charcnt;
 137         if (tz->bit64.leapcnt) {
 138                 *tzf += sizeof(int64_t) * tz->bit64.leapcnt * 2;
 139         }
 140         if (tz->bit64.ttisstdcnt) {
 141                 *tzf += sizeof(unsigned char) * tz->bit64.ttisstdcnt;
 142         }
 143         if (tz->bit64.ttisgmtcnt) {
 144                 *tzf += sizeof(unsigned char) * tz->bit64.ttisgmtcnt;
 145         }
 146 }
 147 
 148 static void read_types(const unsigned char **tzf, timelib_tzinfo *tz)
 149 {
 150         unsigned char *buffer;
 151         int32_t *leap_buffer;
 152         unsigned int i, j;
 153 
 154         buffer = (unsigned char*) timelib_malloc(tz->bit32.typecnt * sizeof(unsigned char) * 6);
 155         if (!buffer) {
 156                 return;
 157         }
 158         memcpy(buffer, *tzf, sizeof(unsigned char) * 6 * tz->bit32.typecnt);
 159         *tzf += sizeof(unsigned char) * 6 * tz->bit32.typecnt;
 160 
 161         tz->type = (ttinfo*) timelib_malloc(tz->bit32.typecnt * sizeof(struct ttinfo));
 162         if (!tz->type) {
 163                 timelib_free(buffer);
 164                 return;
 165         }
 166 
 167         for (i = 0; i < tz->bit32.typecnt; i++) {
 168                 j = i * 6;
 169                 tz->type[i].offset = (buffer[j] * 16777216) + (buffer[j + 1] * 65536) + (buffer[j + 2] * 256) + buffer[j + 3];
 170                 tz->type[i].isdst = buffer[j + 4];
 171                 tz->type[i].abbr_idx = buffer[j + 5];
 172         }
 173         timelib_free(buffer);
 174 
 175         tz->timezone_abbr = (char*) timelib_malloc(tz->bit32.charcnt);
 176         if (!tz->timezone_abbr) {
 177                 return;
 178         }
 179         memcpy(tz->timezone_abbr, *tzf, sizeof(char) * tz->bit32.charcnt);
 180         *tzf += sizeof(char) * tz->bit32.charcnt;
 181 
 182         if (tz->bit32.leapcnt) {
 183                 leap_buffer = (int32_t *) timelib_malloc(tz->bit32.leapcnt * 2 * sizeof(int32_t));
 184                 if (!leap_buffer) {
 185                         return;
 186                 }
 187                 memcpy(leap_buffer, *tzf, sizeof(int32_t) * tz->bit32.leapcnt * 2);
 188                 *tzf += sizeof(int32_t) * tz->bit32.leapcnt * 2;
 189 
 190                 tz->leap_times = (tlinfo*) timelib_malloc(tz->bit32.leapcnt * sizeof(tlinfo));
 191                 if (!tz->leap_times) {
 192                         timelib_free(leap_buffer);
 193                         return;
 194                 }
 195                 for (i = 0; i < tz->bit32.leapcnt; i++) {
 196                         tz->leap_times[i].trans = timelib_conv_int(leap_buffer[i * 2]);
 197                         tz->leap_times[i].offset = timelib_conv_int(leap_buffer[i * 2 + 1]);
 198                 }
 199                 timelib_free(leap_buffer);
 200         }
 201 
 202         if (tz->bit32.ttisstdcnt) {
 203                 buffer = (unsigned char*) timelib_malloc(tz->bit32.ttisstdcnt * sizeof(unsigned char));
 204                 if (!buffer) {
 205                         return;
 206                 }
 207                 memcpy(buffer, *tzf, sizeof(unsigned char) * tz->bit32.ttisstdcnt);
 208                 *tzf += sizeof(unsigned char) * tz->bit32.ttisstdcnt;
 209 
 210                 for (i = 0; i < tz->bit32.ttisstdcnt; i++) {
 211                         tz->type[i].isstdcnt = buffer[i];
 212                 }
 213                 timelib_free(buffer);
 214         }
 215 
 216         if (tz->bit32.ttisgmtcnt) {
 217                 buffer = (unsigned char*) timelib_malloc(tz->bit32.ttisgmtcnt * sizeof(unsigned char));
 218                 if (!buffer) {
 219                         return;
 220                 }
 221                 memcpy(buffer, *tzf, sizeof(unsigned char) * tz->bit32.ttisgmtcnt);
 222                 *tzf += sizeof(unsigned char) * tz->bit32.ttisgmtcnt;
 223 
 224                 for (i = 0; i < tz->bit32.ttisgmtcnt; i++) {
 225                         tz->type[i].isgmtcnt = buffer[i];
 226                 }
 227                 timelib_free(buffer);
 228         }
 229 }
 230 
 231 static void skip_posix_string(const unsigned char **tzf, timelib_tzinfo *tz)
 232 {
 233         int n_count = 0;
 234 
 235         do {
 236                 if (*tzf[0] == '\n') {
 237                         n_count++;
 238                 }
 239                 (*tzf)++;
 240         } while (n_count < 2);
 241 }
 242 
 243 static void read_location(const unsigned char **tzf, timelib_tzinfo *tz)
 244 {
 245         uint32_t buffer[3];
 246         uint32_t comments_len;
 247 
 248         memcpy(&buffer, *tzf, sizeof(buffer));
 249         tz->location.latitude = timelib_conv_int(buffer[0]);
 250         tz->location.latitude = (tz->location.latitude / 100000) - 90;
 251         tz->location.longitude = timelib_conv_int(buffer[1]);
 252         tz->location.longitude = (tz->location.longitude / 100000) - 180;
 253         comments_len = timelib_conv_int(buffer[2]);
 254         *tzf += sizeof(buffer);
 255 
 256         tz->location.comments = timelib_malloc(comments_len + 1);
 257         memcpy(tz->location.comments, *tzf, comments_len);
 258         tz->location.comments[comments_len] = '\0';
 259         *tzf += comments_len;
 260 }
 261 
 262 void timelib_dump_tzinfo(timelib_tzinfo *tz)
 263 {
 264         uint32_t i;
 265 
 266         printf("Country Code:      %s\n", tz->location.country_code);
 267         printf("Geo Location:      %f,%f\n", tz->location.latitude, tz->location.longitude);
 268         printf("Comments:\n%s\n",          tz->location.comments);
 269         printf("BC:                %s\n",  tz->bc ? "" : "yes");
 270         printf("UTC/Local count:   " TIMELIB_ULONG_FMT "\n", (timelib_ulong) tz->bit32.ttisgmtcnt);
 271         printf("Std/Wall count:    " TIMELIB_ULONG_FMT "\n", (timelib_ulong) tz->bit32.ttisstdcnt);
 272         printf("Leap.sec. count:   " TIMELIB_ULONG_FMT "\n", (timelib_ulong) tz->bit32.leapcnt);
 273         printf("Trans. count:      " TIMELIB_ULONG_FMT "\n", (timelib_ulong) tz->bit32.timecnt);
 274         printf("Local types count: " TIMELIB_ULONG_FMT "\n", (timelib_ulong) tz->bit32.typecnt);
 275         printf("Zone Abbr. count:  " TIMELIB_ULONG_FMT "\n", (timelib_ulong) tz->bit32.charcnt);
 276 
 277         printf ("%8s (%12s) = %3d [%5ld %1d %3d '%s' (%d,%d)]\n",
 278                 "", "", 0,
 279                 (long int) tz->type[0].offset,
 280                 tz->type[0].isdst,
 281                 tz->type[0].abbr_idx,
 282                 &tz->timezone_abbr[tz->type[0].abbr_idx],
 283                 tz->type[0].isstdcnt,
 284                 tz->type[0].isgmtcnt
 285                 );
 286         for (i = 0; i < tz->bit32.timecnt; i++) {
 287                 printf ("%08X (%12d) = %3d [%5ld %1d %3d '%s' (%d,%d)]\n",
 288                         tz->trans[i], tz->trans[i], tz->trans_idx[i],
 289                         (long int) tz->type[tz->trans_idx[i]].offset,
 290                         tz->type[tz->trans_idx[i]].isdst,
 291                         tz->type[tz->trans_idx[i]].abbr_idx,
 292                         &tz->timezone_abbr[tz->type[tz->trans_idx[i]].abbr_idx],
 293                         tz->type[tz->trans_idx[i]].isstdcnt,
 294                         tz->type[tz->trans_idx[i]].isgmtcnt
 295                         );
 296         }
 297         for (i = 0; i < tz->bit32.leapcnt; i++) {
 298                 printf ("%08X (%12ld) = %d\n",
 299                         tz->leap_times[i].trans,
 300                         (long) tz->leap_times[i].trans,
 301                         tz->leap_times[i].offset);
 302         }
 303 }
 304 
 305 static int seek_to_tz_position(const unsigned char **tzf, char *timezone, const timelib_tzdb *tzdb)
 306 {
 307         int left = 0, right = tzdb->index_size - 1;
 308 #ifdef HAVE_SETLOCALE
 309         char *cur_locale = NULL, *tmp;
 310 
 311         tmp = setlocale(LC_CTYPE, NULL);
 312         if (tmp) {
 313                 cur_locale = timelib_strdup(tmp);
 314         }
 315         setlocale(LC_CTYPE, "C");
 316 #endif
 317 
 318         do {
 319                 int mid = ((unsigned)left + right) >> 1;
 320                 int cmp = strcasecmp(timezone, tzdb->index[mid].id);
 321 
 322                 if (cmp < 0) {
 323                         right = mid - 1;
 324                 } else if (cmp > 0) {
 325                         left = mid + 1;
 326                 } else { /* (cmp == 0) */
 327                         (*tzf) = &(tzdb->data[tzdb->index[mid].pos]);
 328 #ifdef HAVE_SETLOCALE
 329                         setlocale(LC_CTYPE, cur_locale);
 330                         if (cur_locale) timelib_free(cur_locale);
 331 #endif
 332                         return 1;
 333                 }
 334 
 335         } while (left <= right);
 336 
 337 #ifdef HAVE_SETLOCALE
 338         setlocale(LC_CTYPE, cur_locale);
 339         if (cur_locale) timelib_free(cur_locale);
 340 #endif
 341         return 0;
 342 }
 343 
 344 const timelib_tzdb *timelib_builtin_db(void)
 345 {
 346         return &timezonedb_builtin;
 347 }
 348 
 349 const timelib_tzdb_index_entry *timelib_timezone_builtin_identifiers_list(int *count)
 350 {
 351         *count = sizeof(timezonedb_idx_builtin) / sizeof(*timezonedb_idx_builtin);
 352         return timezonedb_idx_builtin;
 353 }
 354 
 355 int timelib_timezone_id_is_valid(char *timezone, const timelib_tzdb *tzdb)
 356 {
 357         const unsigned char *tzf;
 358         return (seek_to_tz_position(&tzf, timezone, tzdb));
 359 }
 360 
 361 static void skip_64bit_preamble(const unsigned char **tzf, timelib_tzinfo *tz)
 362 {
 363         *tzf += 20;
 364 }
 365 
 366 static void read_64bit_header(const unsigned char **tzf, timelib_tzinfo *tz)
 367 {
 368         uint32_t buffer[6];
 369 
 370         memcpy(&buffer, *tzf, sizeof(buffer));
 371         tz->bit64.ttisgmtcnt = timelib_conv_int(buffer[0]);
 372         tz->bit64.ttisstdcnt = timelib_conv_int(buffer[1]);
 373         tz->bit64.leapcnt    = timelib_conv_int(buffer[2]);
 374         tz->bit64.timecnt    = timelib_conv_int(buffer[3]);
 375         tz->bit64.typecnt    = timelib_conv_int(buffer[4]);
 376         tz->bit64.charcnt    = timelib_conv_int(buffer[5]);
 377         *tzf += sizeof(buffer);
 378 }
 379 
 380 timelib_tzinfo *timelib_parse_tzfile(char *timezone, const timelib_tzdb *tzdb)
 381 {
 382         const unsigned char *tzf;
 383         timelib_tzinfo *tmp;
 384         int version;
 385 
 386         if (seek_to_tz_position(&tzf, timezone, tzdb)) {
 387                 tmp = timelib_tzinfo_ctor(timezone);
 388 
 389                 version = read_preamble(&tzf, tmp);
 390                 read_header(&tzf, tmp);
 391                 read_transistions(&tzf, tmp);
 392                 read_types(&tzf, tmp);
 393                 if (version == 2) {
 394                         skip_64bit_preamble(&tzf, tmp);
 395                         read_64bit_header(&tzf, tmp);
 396                         skip_64bit_transistions(&tzf, tmp);
 397                         skip_64bit_types(&tzf, tmp);
 398                         skip_posix_string(&tzf, tmp);
 399                 }
 400                 read_location(&tzf, tmp);
 401         } else {
 402                 tmp = NULL;
 403         }
 404 
 405         return tmp;
 406 }
 407 
 408 static ttinfo* fetch_timezone_offset(timelib_tzinfo *tz, timelib_sll ts, timelib_sll *transition_time)
 409 {
 410         uint32_t i;
 411 
 412         /* If there is no transition time, we pick the first one, if that doesn't
 413          * exist we return NULL */
 414         if (!tz->bit32.timecnt || !tz->trans) {
 415                 *transition_time = 0;
 416                 if (tz->bit32.typecnt == 1) {
 417                         return &(tz->type[0]);
 418                 }
 419                 return NULL;
 420         }
 421 
 422         /* If the TS is lower than the first transition time, then we scan over
 423          * all the transition times to find the first non-DST one, or the first
 424          * one in case there are only DST entries. Not sure which smartass came up
 425          * with this idea in the first though :) */
 426         if (ts < tz->trans[0]) {
 427                 uint32_t j;
 428 
 429                 *transition_time = 0;
 430                 j = 0;
 431                 while (j < tz->bit32.timecnt && tz->type[tz->trans_idx[j]].isdst) {
 432                         ++j;
 433                 }
 434                 if (j == tz->bit32.timecnt) {
 435                         j = 0;
 436                 }
 437                 return &(tz->type[tz->trans_idx[j]]);
 438         }
 439 
 440         /* In all other cases we loop through the available transtion times to find
 441          * the correct entry */
 442         for (i = 0; i < tz->bit32.timecnt; i++) {
 443                 if (ts < tz->trans[i]) {
 444                         *transition_time = tz->trans[i - 1];
 445                         return &(tz->type[tz->trans_idx[i - 1]]);
 446                 }
 447         }
 448         *transition_time = tz->trans[tz->bit32.timecnt - 1];
 449         return &(tz->type[tz->trans_idx[tz->bit32.timecnt - 1]]);
 450 }
 451 
 452 static tlinfo* fetch_leaptime_offset(timelib_tzinfo *tz, timelib_sll ts)
 453 {
 454         int i;
 455 
 456         if (!tz->bit32.leapcnt || !tz->leap_times) {
 457                 return NULL;
 458         }
 459 
 460         for (i = tz->bit32.leapcnt - 1; i > 0; i--) {
 461                 if (ts > tz->leap_times[i].trans) {
 462                         return &(tz->leap_times[i]);
 463                 }
 464         }
 465         return NULL;
 466 }
 467 
 468 int timelib_timestamp_is_in_dst(timelib_sll ts, timelib_tzinfo *tz)
 469 {
 470         ttinfo *to;
 471         timelib_sll dummy;
 472 
 473         if ((to = fetch_timezone_offset(tz, ts, &dummy))) {
 474                 return to->isdst;
 475         }
 476         return -1;
 477 }
 478 
 479 timelib_time_offset *timelib_get_time_zone_info(timelib_sll ts, timelib_tzinfo *tz)
 480 {
 481         ttinfo *to;
 482         tlinfo *tl;
 483         int32_t offset = 0, leap_secs = 0;
 484         char *abbr;
 485         timelib_time_offset *tmp = timelib_time_offset_ctor();
 486         timelib_sll                transistion_time;
 487 
 488         if ((to = fetch_timezone_offset(tz, ts, &transistion_time))) {
 489                 offset = to->offset;
 490                 abbr = &(tz->timezone_abbr[to->abbr_idx]);
 491                 tmp->is_dst = to->isdst;
 492                 tmp->transistion_time = transistion_time;
 493         } else {
 494                 offset = 0;
 495                 abbr = tz->timezone_abbr;
 496                 tmp->is_dst = 0;
 497                 tmp->transistion_time = 0;
 498         }
 499 
 500         if ((tl = fetch_leaptime_offset(tz, ts))) {
 501                 leap_secs = -tl->offset;
 502         }
 503 
 504         tmp->offset = offset;
 505         tmp->leap_secs = leap_secs;
 506         tmp->abbr = abbr ? timelib_strdup(abbr) : timelib_strdup("GMT");
 507 
 508         return tmp;
 509 }
 510 
 511 timelib_sll timelib_get_current_offset(timelib_time *t)
 512 {
 513         timelib_time_offset *gmt_offset;
 514         timelib_sll retval;
 515 
 516         switch (t->zone_type) {
 517                 case TIMELIB_ZONETYPE_ABBR:
 518                 case TIMELIB_ZONETYPE_OFFSET:
 519                         return (t->z + t->dst) * -60;
 520 
 521                 case TIMELIB_ZONETYPE_ID:
 522                         gmt_offset = timelib_get_time_zone_info(t->sse, t->tz_info);
 523                         retval = gmt_offset->offset;
 524                         timelib_time_offset_dtor(gmt_offset);
 525                         return retval;
 526 
 527                 default:
 528                         return 0;
 529         }
 530 }