2 * Copyright © 2010 Codethink Limited
4 * This library is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2 of the licence, or (at your option) any later version.
9 * This library is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, write to the
16 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
17 * Boston, MA 02111-1307, USA.
19 * Author: Ryan Lortie <desrt@desrt.ca>
26 #include "gtimezone.h"
32 #include "gmappedfile.h"
33 #include "gtestutils.h"
34 #include "gfileutils.h"
35 #include "gstrfuncs.h"
40 #include "gdatetime.h"
51 * @short_description: a structure representing a time zone
52 * @see_also: #GDateTime
54 * #GTimeZone is a structure that represents a time zone, at no
55 * particular point in time. It is refcounted and immutable.
57 * A time zone contains a number of intervals. Each interval has
58 * an abbreviation to describe it, an offet to UTC and a flag indicating
59 * if the daylight savings time is in effect during that interval. A
60 * time zone always has at least one interval -- interval 0.
62 * Every UTC time is contained within exactly one interval, but a given
63 * local time may be contained within zero, one or two intervals (due to
64 * incontinuities associated with daylight savings time).
66 * An interval may refer to a specific period of time (eg: the duration
67 * of daylight savings time during 2010) or it may refer to many periods
68 * of time that share the same properties (eg: all periods of daylight
69 * savings time). It is also possible (usually for political reasons)
70 * that some properties (like the abbreviation) change between intervals
71 * without other properties changing.
73 * #GTimeZone is available since GLib 2.26.
79 * #GDateTime is an opaque structure whose members cannot be accessed
85 /* IANA zoneinfo file format {{{1 */
88 typedef struct { gchar bytes[8]; } gint64_be;
89 typedef struct { gchar bytes[4]; } gint32_be;
90 typedef struct { gchar bytes[4]; } guint32_be;
92 static inline gint64 gint64_from_be (const gint64_be be) {
93 gint64 tmp; memcpy (&tmp, &be, sizeof tmp); return GINT64_FROM_BE (tmp);
96 static inline gint32 gint32_from_be (const gint32_be be) {
97 gint32 tmp; memcpy (&tmp, &be, sizeof tmp); return GINT32_FROM_BE (tmp);
100 static inline guint32 guint32_from_be (const guint32_be be) {
101 guint32 tmp; memcpy (&tmp, &be, sizeof tmp); return GUINT32_FROM_BE (tmp);
104 /* The layout of an IANA timezone file header */
109 guchar tzh_reserved[15];
111 guint32_be tzh_ttisgmtcnt;
112 guint32_be tzh_ttisstdcnt;
113 guint32_be tzh_leapcnt;
114 guint32_be tzh_timecnt;
115 guint32_be tzh_typecnt;
116 guint32_be tzh_charcnt;
126 /* A Transition Date structure for TZ Rules, an intermediate structure
127 for parsing MSWindows and Environment-variable time zones. It
128 Generalizes MSWindows's SYSTEMTIME struct.
142 /* POSIX Timezone abbreviations are typically 3 or 4 characters, but
143 Microsoft uses 32-character names. We'll use one larger to ensure
144 we have room for the terminating \0.
148 /* A MSWindows-style time zone transition rule. Generalizes the
149 MSWindows TIME_ZONE_INFORMATION struct. Also used to compose time
150 zones from tzset-style identifiers.
157 TimeZoneDate dlt_start;
158 TimeZoneDate dlt_end;
159 gchar std_name[NAME_SIZE];
160 gchar dlt_name[NAME_SIZE];
163 /* GTimeZone's internal representation of a Daylight Savings (Summer)
170 gboolean is_standard;
175 /* GTimeZone's representation of a transition time to or from Daylight
176 Savings (Summer) time and Standard time for the zone. */
183 /* GTimeZone structure */
187 GArray *t_info; /* Array of TransitionInfo */
188 GArray *transitions; /* Array of Transition */
192 G_LOCK_DEFINE_STATIC (time_zones);
193 static GHashTable/*<string?, GTimeZone>*/ *time_zones;
195 #define MIN_TZYEAR 1916 /* Daylight Savings started in WWI */
196 #define MAX_TZYEAR 2999 /* And it's not likely ever to go away, but
197 there's no point in getting carried
204 * Decreases the reference count on @tz.
209 g_time_zone_unref (GTimeZone *tz)
214 ref_count = g_atomic_int_get (&tz->ref_count);
216 g_assert (ref_count > 0);
220 if (tz->name != NULL)
224 /* someone else might have grabbed a ref in the meantime */
225 if G_UNLIKELY (g_atomic_int_get (&tz->ref_count) != 1)
227 G_UNLOCK(time_zones);
231 g_hash_table_remove (time_zones, tz->name);
232 G_UNLOCK(time_zones);
235 if (tz->t_info != NULL)
236 g_array_free (tz->t_info, TRUE);
237 if (tz->transitions != NULL)
238 g_array_free (tz->transitions, TRUE);
241 g_slice_free (GTimeZone, tz);
244 else if G_UNLIKELY (!g_atomic_int_compare_and_exchange (&tz->ref_count,
254 * Increases the reference count on @tz.
256 * Returns: a new reference to @tz.
261 g_time_zone_ref (GTimeZone *tz)
263 g_assert (tz->ref_count > 0);
265 g_atomic_int_inc (&tz->ref_count);
270 /* fake zoneinfo creation (for RFC3339/ISO 8601 timezones) {{{1 */
272 * parses strings of the form h or hh[[:]mm[[[:]ss]]] where:
278 parse_time (const gchar *time_,
281 if (*time_ < '0' || '9' < *time_)
284 *offset = 60 * 60 * (*time_++ - '0');
291 if (*time_ < '0' || '9' < *time_)
295 *offset += 60 * 60 * (*time_++ - '0');
297 if (*offset > 23 * 60 * 60)
307 if (*time_ < '0' || '5' < *time_)
310 *offset += 10 * 60 * (*time_++ - '0');
312 if (*time_ < '0' || '9' < *time_)
315 *offset += 60 * (*time_++ - '0');
323 if (*time_ < '0' || '5' < *time_)
326 *offset += 10 * (*time_++ - '0');
328 if (*time_ < '0' || '9' < *time_)
331 *offset += *time_++ - '0';
333 return *time_ == '\0';
337 parse_constant_offset (const gchar *name,
340 if (g_strcmp0 (name, "UTC") == 0)
346 if (*name >= '0' && '9' >= *name)
347 return parse_time (name, offset);
356 return parse_time (name, offset);
359 if (parse_time (name, offset))
371 zone_for_constant_offset (GTimeZone *gtz, const gchar *name)
376 if (name == NULL || !parse_constant_offset (name, &offset))
379 info.gmt_offset = offset;
381 info.is_standard = TRUE;
383 info.abbrev = g_strdup (name);
386 gtz->t_info = g_array_sized_new (FALSE, TRUE, sizeof (TransitionInfo), 1);
387 g_array_append_val (gtz->t_info, info);
389 /* Constant offset, no transitions */
390 gtz->transitions = NULL;
395 zone_info_unix (const gchar *identifier)
398 GMappedFile *file = NULL;
399 GBytes *zoneinfo = NULL;
401 /* identifier can be a relative or absolute path name;
402 if relative, it is interpreted starting from /usr/share/zoneinfo
403 while the POSIX standard says it should start with :,
404 glibc allows both syntaxes, so we should too */
405 if (identifier != NULL)
409 tzdir = getenv ("TZDIR");
411 tzdir = "/usr/share/zoneinfo";
413 if (*identifier == ':')
416 if (g_path_is_absolute (identifier))
417 filename = g_strdup (identifier);
419 filename = g_build_filename (tzdir, identifier, NULL);
422 filename = g_strdup ("/etc/localtime");
424 file = g_mapped_file_new (filename, FALSE, NULL);
427 zoneinfo = g_bytes_new_with_free_func (g_mapped_file_get_contents (file),
428 g_mapped_file_get_length (file),
429 (GDestroyNotify)g_mapped_file_unref,
430 g_mapped_file_ref (file));
431 g_mapped_file_unref (file);
438 init_zone_from_iana_info (GTimeZone *gtz, GBytes *zoneinfo)
442 guint32 time_count, type_count, leap_count, isgmt_count;
443 guint32 isstd_count, char_count ;
444 guint8 *tz_transitions, *tz_type_index, *tz_ttinfo;
445 guint8 *tz_leaps, *tz_isgmt, *tz_isstd;
447 gsize timesize = sizeof (gint32), countsize = sizeof (gint32);
448 const struct tzhead *header = g_bytes_get_data (zoneinfo, &size);
450 g_return_if_fail (size >= sizeof (struct tzhead) &&
451 memcmp (header, "TZif", 4) == 0);
453 if (header->tzh_version == '2')
455 /* Skip ahead to the newer 64-bit data if it's available. */
456 header = (const struct tzhead *)
457 (((const gchar *) (header + 1)) +
458 guint32_from_be(header->tzh_ttisgmtcnt) +
459 guint32_from_be(header->tzh_ttisstdcnt) +
460 8 * guint32_from_be(header->tzh_leapcnt) +
461 5 * guint32_from_be(header->tzh_timecnt) +
462 6 * guint32_from_be(header->tzh_typecnt) +
463 guint32_from_be(header->tzh_charcnt));
464 timesize = sizeof (gint64);
466 time_count = guint32_from_be(header->tzh_timecnt);
467 type_count = guint32_from_be(header->tzh_typecnt);
468 leap_count = guint32_from_be(header->tzh_leapcnt);
469 isgmt_count = guint32_from_be(header->tzh_ttisgmtcnt);
470 isstd_count = guint32_from_be(header->tzh_ttisstdcnt);
471 char_count = guint32_from_be(header->tzh_charcnt);
473 g_assert (type_count == isgmt_count);
474 g_assert (type_count == isstd_count);
476 tz_transitions = ((guint8 *) (header) + sizeof (*header));
477 tz_type_index = tz_transitions + timesize * time_count;
478 tz_ttinfo = tz_type_index + time_count;
479 tz_abbrs = tz_ttinfo + sizeof (struct ttinfo) * type_count;
480 tz_leaps = tz_abbrs + char_count;
481 tz_isstd = tz_leaps + (timesize + countsize) * leap_count;
482 tz_isgmt = tz_isstd + isstd_count;
484 gtz->t_info = g_array_sized_new (FALSE, TRUE, sizeof (TransitionInfo),
486 gtz->transitions = g_array_sized_new (FALSE, TRUE, sizeof (Transition),
489 for (index = 0; index < type_count; index++)
491 TransitionInfo t_info;
492 struct ttinfo info = ((struct ttinfo*)tz_ttinfo)[index];
493 t_info.gmt_offset = gint32_from_be (info.tt_gmtoff);
494 t_info.is_dst = info.tt_isdst ? TRUE : FALSE;
495 t_info.is_standard = tz_isstd[index] ? TRUE : FALSE;
496 t_info.is_gmt = tz_isgmt[index] ? TRUE : FALSE;
497 t_info.abbrev = g_strdup ((gchar *) &tz_abbrs[info.tt_abbrind]);
498 g_array_append_val (gtz->t_info, t_info);
501 for (index = 0; index < time_count; index++)
504 if (header->tzh_version == '2')
505 trans.time = gint64_from_be (((gint64_be*)tz_transitions)[index]);
507 trans.time = gint32_from_be (((gint32_be*)tz_transitions)[index]);
508 trans.info_index = tz_type_index[index];
509 g_assert (trans.info_index >= 0);
510 g_assert (trans.info_index < gtz->t_info->len);
511 g_array_append_val (gtz->transitions, trans);
515 #elif defined (G_OS_WIN32)
518 copy_windows_systemtime (SYSTEMTIME *s_time, TimeZoneDate *tzdate)
520 tzdate->sec = s_time->wSecond;
521 tzdate->min = s_time->wMinute;
522 tzdate->hour = s_time->wHour;
523 tzdate->mon = s_time->wMonth;
524 tzdate->year = s_time->wYear;
525 tzdate->wday = s_time->wDayOfWeek ? s_time->wDayOfWeek : 7;
529 tzdate->mday = s_time->wDay;
533 tzdate->week = s_time->wDay;
536 /* UTC = local time + bias while local time = UTC + offset */
538 rule_from_windows_time_zone_info (TimeZoneRule *rule,
539 TIME_ZONE_INFORMATION *tzi)
542 if (tzi->StandardDate.wMonth)
544 rule->std_offset = -(tzi->Bias + tzi->StandardBias) * 60;
545 rule->dlt_offset = -(tzi->Bias + tzi->DaylightBias) * 60;
546 copy_windows_systemtime (&(tzi->DaylightDate), &(rule->dlt_start));
548 copy_windows_systemtime (&(tzi->StandardDate), &(rule->dlt_end));
554 rule->std_offset = -tzi->Bias * 60;
555 rule->dlt_start.mon = 0;
557 strncpy (rule->std_name, (gchar*)tzi->StandardName, NAME_SIZE - 1);
558 strncpy (rule->dlt_name, (gchar*)tzi->DaylightName, NAME_SIZE - 1);
562 windows_default_tzname (void)
564 const gchar *subkey =
565 "SYSTEM\\CurrentControlSet\\Control\\TimeZoneInformation";
567 gchar *key_name = NULL;
568 if (RegOpenKeyExA (HKEY_LOCAL_MACHINE, subkey, 0,
569 KEY_QUERY_VALUE, &key) == ERROR_SUCCESS)
572 if (RegQueryValueExA (key, "TimeZoneKeyName", NULL, NULL,
573 NULL, &size) == ERROR_SUCCESS)
575 key_name = g_malloc ((gint)size);
576 if (RegQueryValueExA (key, "TimeZoneKeyName", NULL, NULL,
577 (LPBYTE)key_name, &size) != ERROR_SUCCESS)
593 SYSTEMTIME StandardDate;
594 SYSTEMTIME DaylightDate;
598 system_time_copy (SYSTEMTIME *orig, SYSTEMTIME *target)
600 g_return_if_fail (orig != NULL);
601 g_return_if_fail (target != NULL);
603 target->wYear = orig->wYear;
604 target->wMonth = orig->wMonth;
605 target->wDayOfWeek = orig->wDayOfWeek;
606 target->wDay = orig->wDay;
607 target->wHour = orig->wHour;
608 target->wMinute = orig->wMinute;
609 target->wSecond = orig->wSecond;
610 target->wMilliseconds = orig->wMilliseconds;
614 register_tzi_to_tzi (RegTZI *reg, TIME_ZONE_INFORMATION *tzi)
616 g_return_if_fail (reg != NULL);
617 g_return_if_fail (tzi != NULL);
618 tzi->Bias = reg->Bias;
619 system_time_copy (&(reg->StandardDate), &(tzi->StandardDate));
620 tzi->StandardBias = reg->StandardBias;
621 system_time_copy (&(reg->DaylightDate), &(tzi->DaylightDate));
622 tzi->DaylightBias = reg->DaylightBias;
626 rules_from_windows_time_zone (const gchar *identifier, TimeZoneRule **rules)
629 gchar *subkey, *subkey_dynamic;
630 gchar *key_name = NULL;
631 const gchar *reg_key =
632 "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones\\";
633 TIME_ZONE_INFORMATION tzi;
636 RegTZI regtzi, regtzi_prev;
642 key_name = windows_default_tzname ();
644 key_name = g_strdup (identifier);
649 subkey = g_strconcat (reg_key, key_name, NULL);
650 subkey_dynamic = g_strconcat (subkey, "\\Dynamic DST", NULL);
652 if (RegOpenKeyExA (HKEY_LOCAL_MACHINE, subkey, 0,
653 KEY_QUERY_VALUE, &key) != ERROR_SUCCESS)
655 size = sizeof tzi.StandardName;
656 if (RegQueryValueExA (key, "Std", NULL, NULL,
657 (LPBYTE)&(tzi.StandardName), &size) != ERROR_SUCCESS)
659 if (RegQueryValueExA (key, "Dlt", NULL, NULL,
660 (LPBYTE)&(tzi.DaylightName), &size) != ERROR_SUCCESS)
664 if (RegOpenKeyExA (HKEY_LOCAL_MACHINE, subkey_dynamic, 0,
665 KEY_QUERY_VALUE, &key) == ERROR_SUCCESS)
672 if (RegQueryValueExA (key, "FirstEntry", NULL, NULL,
673 (LPBYTE) &first, &size) != ERROR_SUCCESS)
677 if (RegQueryValueExA (key, "LastEntry", NULL, NULL,
678 (LPBYTE) &last, &size) != ERROR_SUCCESS)
681 rules_num = last - first + 2;
682 *rules = g_new0 (TimeZoneRule, rules_num);
684 for (year = first, i = 0; year <= last; year++)
686 s = g_strdup_printf ("%d", year);
688 size = sizeof regtzi;
689 if (RegQueryValueExA (key, s, NULL, NULL,
690 (LPBYTE) ®tzi, &size) != ERROR_SUCCESS)
699 if (year > first && memcmp (®tzi_prev, ®tzi, sizeof regtzi) == 0)
702 memcpy (®tzi_prev, ®tzi, sizeof regtzi);
704 register_tzi_to_tzi (®tzi, &tzi);
705 rule_from_windows_time_zone_info (&(*rules)[i], &tzi);
706 (*rules)[i++].start_year = year;
714 else if (RegOpenKeyExA (HKEY_LOCAL_MACHINE, subkey, 0,
715 KEY_QUERY_VALUE, &key) == ERROR_SUCCESS)
717 size = sizeof regtzi;
718 if (RegQueryValueExA (key, "TZI", NULL, NULL,
719 (LPBYTE) ®tzi, &size) == ERROR_SUCCESS)
722 *rules = g_new0 (TimeZoneRule, 2);
723 register_tzi_to_tzi (®tzi, &tzi);
724 rule_from_windows_time_zone_info (&(*rules)[0], &tzi);
730 g_free (subkey_dynamic);
736 (*rules)[0].start_year = MIN_TZYEAR;
737 if ((*rules)[rules_num - 2].start_year < MAX_TZYEAR)
738 (*rules)[rules_num - 1].start_year = MAX_TZYEAR;
740 (*rules)[rules_num - 1].start_year = (*rules)[rules_num - 2].start_year + 1;
751 find_relative_date (TimeZoneDate *buffer)
755 g_date_clear (&date, 1);
758 /* Get last day if last is needed, first day otherwise */
759 if (buffer->mon == 13 || buffer->mon == 14) /* Julian Date */
761 g_date_set_dmy (&date, 1, 1, buffer->year);
762 if (wday >= 59 && buffer->mon == 13 && g_date_is_leap_year (buffer->year))
763 g_date_add_days (&date, wday);
765 g_date_add_days (&date, wday - 1);
766 buffer->mon = (int) g_date_get_month (&date);
767 buffer->mday = (int) g_date_get_day (&date);
773 guint days_in_month = g_date_days_in_month (buffer->mon, buffer->year);
774 GDateWeekday first_wday;
776 g_date_set_dmy (&date, 1, buffer->mon, buffer->year);
777 first_wday = g_date_get_weekday (&date);
779 if (first_wday > wday)
781 /* week is 1 <= w <= 5, we need 0-based */
782 days = 7 * (buffer->week - 1) + wday - first_wday;
784 while (days > days_in_month)
787 g_date_add_days (&date, days);
789 buffer->mday = g_date_get_day (&date);
793 /* Offset is previous offset of local time. Returns 0 if month is 0 */
795 boundary_for_year (TimeZoneDate *boundary,
801 const guint64 unix_epoch_start = 719163L;
802 const guint64 seconds_per_day = 86400L;
808 if (boundary->year == 0)
813 find_relative_date (&buffer);
816 g_assert (buffer.year == year);
817 g_date_clear (&date, 1);
818 g_date_set_dmy (&date, buffer.mday, buffer.mon, buffer.year);
819 return ((g_date_get_julian (&date) - unix_epoch_start) * seconds_per_day +
820 buffer.hour * 3600 + buffer.min * 60 + buffer.sec - offset);
824 fill_transition_info_from_rule (TransitionInfo *info,
828 gint offset = is_dst ? rule->dlt_offset : rule->std_offset;
829 gchar *name = is_dst ? rule->dlt_name : rule->std_name;
831 info->gmt_offset = offset;
832 info->is_dst = is_dst;
833 info->is_standard = FALSE;
834 info->is_gmt = FALSE;
837 info->abbrev = g_strdup (name);
840 info->abbrev = g_strdup_printf ("%+03d%02d",
842 (int) abs (offset / 60) % 60);
846 init_zone_from_rules (GTimeZone *gtz,
850 guint type_count = 0, trans_count = 0, info_index = 0;
851 guint ri; /* rule index */
852 gboolean skip_first_std_trans = TRUE;
858 /* Last rule only contains max year */
859 for (ri = 0; ri < rules_num - 1; ri++)
861 if (rules[ri].dlt_start.mon || rules[ri].dlt_end.mon)
863 guint rulespan = (rules[ri + 1].start_year - rules[ri].start_year);
864 guint transitions = rules[ri].dlt_start.mon > 0 ? 1 : 0;
865 transitions += rules[ri].dlt_end.mon > 0 ? 1 : 0;
866 type_count += rules[ri].dlt_start.mon > 0 ? 2 : 1;
867 trans_count += transitions * rulespan;
873 gtz->t_info = g_array_sized_new (FALSE, TRUE, sizeof (TransitionInfo), type_count);
874 gtz->transitions = g_array_sized_new (FALSE, TRUE, sizeof (Transition), trans_count);
876 last_offset = rules[0].std_offset;
878 for (ri = 0; ri < rules_num - 1; ri++)
880 if ((rules[ri].std_offset || rules[ri].dlt_offset) &&
881 rules[ri].dlt_start.mon == 0 && rules[ri].dlt_end.mon == 0)
883 TransitionInfo std_info;
885 fill_transition_info_from_rule (&std_info, &(rules[ri]), FALSE);
886 g_array_append_val (gtz->t_info, std_info);
889 ((rules[ri - 1].dlt_start.mon > 12 &&
890 rules[ri - 1].dlt_start.wday > rules[ri - 1].dlt_end.wday) ||
891 rules[ri - 1].dlt_start.mon > rules[ri - 1].dlt_end.mon))
893 /* The previous rule was a southern hemisphere rule that
894 starts the year with DST, so we need to add a
895 transition to return to standard time */
896 guint year = rules[ri].start_year;
897 gint64 std_time = boundary_for_year (&rules[ri].dlt_end,
899 Transition std_trans = {std_time, info_index};
900 g_array_append_val (gtz->transitions, std_trans);
903 last_offset = rules[ri].std_offset;
905 skip_first_std_trans = TRUE;
907 else if (rules[ri].std_offset || rules[ri].dlt_offset)
909 const guint start_year = rules[ri].start_year;
910 const guint end_year = rules[ri + 1].start_year;
913 TransitionInfo std_info, dlt_info;
914 if (rules[ri].dlt_start.mon > 12)
915 dlt_first = rules[ri].dlt_start.wday > rules[ri].dlt_end.wday;
917 dlt_first = rules[ri].dlt_start.mon > rules[ri].dlt_end.mon;
918 /* Standard rules are always even, because before the first
919 transition is always standard time, and 0 is even. */
920 fill_transition_info_from_rule (&std_info, &(rules[ri]), FALSE);
921 fill_transition_info_from_rule (&dlt_info, &(rules[ri]), TRUE);
923 g_array_append_val (gtz->t_info, std_info);
924 g_array_append_val (gtz->t_info, dlt_info);
926 /* Transition dates. We hope that a year which ends daylight
927 time in a southern-hemisphere country (i.e., one that
928 begins the year in daylight time) will include a rule
929 which has only a dlt_end. */
930 for (year = start_year; year < end_year; year++)
932 gint32 dlt_offset = (dlt_first ? last_offset :
933 rules[ri].dlt_offset);
934 gint32 std_offset = (dlt_first ? rules[ri].std_offset :
936 /* NB: boundary_for_year returns 0 if mon == 0 */
937 gint64 std_time = boundary_for_year (&rules[ri].dlt_end,
939 gint64 dlt_time = boundary_for_year (&rules[ri].dlt_start,
941 Transition std_trans = {std_time, info_index};
942 Transition dlt_trans = {dlt_time, info_index + 1};
943 last_offset = (dlt_first ? rules[ri].dlt_offset :
944 rules[ri].std_offset);
947 if (skip_first_std_trans)
948 skip_first_std_trans = FALSE;
950 g_array_append_val (gtz->transitions, std_trans);
952 g_array_append_val (gtz->transitions, dlt_trans);
957 g_array_append_val (gtz->transitions, dlt_trans);
959 g_array_append_val (gtz->transitions, std_trans);
967 ((rules[ri - 1].dlt_start.mon > 12 &&
968 rules[ri - 1].dlt_start.wday > rules[ri - 1].dlt_end.wday) ||
969 rules[ri - 1].dlt_start.mon > rules[ri - 1].dlt_end.mon))
971 /* The previous rule was a southern hemisphere rule that
972 starts the year with DST, so we need to add a
973 transition to return to standard time */
975 guint year = rules[ri].start_year;
977 fill_transition_info_from_rule (&info, &(rules[ri - 1]), FALSE);
978 g_array_append_val (gtz->t_info, info);
979 trans.time = boundary_for_year (&rules[ri - 1].dlt_end,
981 trans.info_index = info_index;
982 g_array_append_val (gtz->transitions, trans);
987 * parses date[/time] for parsing TZ environment variable
989 * date is either Mm.w.d, Jn or N
996 * time is either h or hh[[:]mm[[[:]ss]]]
1002 parse_mwd_boundary (gchar **pos, TimeZoneDate *boundary)
1004 gint month, week, day;
1006 if (**pos == '\0' || **pos < '0' || '9' < **pos)
1009 month = *(*pos)++ - '0';
1011 if ((month == 1 && **pos >= '0' && '2' >= **pos) ||
1012 (month == 0 && **pos >= '0' && '9' >= **pos))
1015 month += *(*pos)++ - '0';
1018 if (*(*pos)++ != '.' || month == 0)
1021 if (**pos == '\0' || **pos < '1' || '5' < **pos)
1024 week = *(*pos)++ - '0';
1026 if (*(*pos)++ != '.')
1029 if (**pos == '\0' || **pos < '0' || '6' < **pos)
1032 day = *(*pos)++ - '0';
1038 boundary->mon = month;
1039 boundary->week = week;
1040 boundary->wday = day;
1044 /* Different implementations of tzset interpret the Julian day field
1045 differently. For example, Linux specifies that it should be 1-based
1046 (1 Jan is JD 1) for both Jn and n formats, while zOS and BSD
1047 specify that a Jn JD is 1-based while an n JD is 0-based. Rather
1048 than trying to follow different specs, we will follow GDate's
1049 practice thatIn order to keep it simple, we will follow Linux's
1053 parse_julian_boundary (gchar** pos, TimeZoneDate *boundary,
1054 gboolean ignore_leap)
1059 while (**pos >= '0' && '9' >= **pos)
1062 day += *(*pos)++ - '0';
1065 if (day < 1 || 365 < day)
1068 g_date_clear (&date, 1);
1069 g_date_set_julian (&date, day);
1071 boundary->mon = (int) g_date_get_month (&date);
1072 boundary->mday = (int) g_date_get_day (&date);
1075 if (!ignore_leap && day >= 59)
1082 parse_tz_boundary (const gchar *identifier,
1083 TimeZoneDate *boundary)
1087 pos = (gchar*)identifier;
1088 /* Month-week-weekday */
1092 if (!parse_mwd_boundary (&pos, boundary))
1095 /* Julian date which ignores Feb 29 in leap years */
1096 else if (*pos == 'J')
1099 if (!parse_julian_boundary (&pos, boundary, FALSE))
1102 /* Julian date which counts Feb 29 in leap years */
1103 else if (*pos >= '0' && '9' >= *pos)
1105 if (!parse_julian_boundary (&pos, boundary, TRUE))
1117 if (!parse_time (++pos, &offset))
1120 boundary->hour = offset / 3600;
1121 boundary->min = (offset / 60) % 60;
1122 boundary->sec = offset % 3600;
1133 return *pos == '\0';
1138 create_ruleset_from_rule (TimeZoneRule **rules, TimeZoneRule *rule)
1140 *rules = g_new0 (TimeZoneRule, 2);
1142 (*rules)[0].start_year = MIN_TZYEAR;
1143 (*rules)[1].start_year = MAX_TZYEAR;
1145 (*rules)[0].std_offset = -rule->std_offset;
1146 (*rules)[0].dlt_offset = -rule->dlt_offset;
1147 (*rules)[0].dlt_start = rule->dlt_start;
1148 (*rules)[0].dlt_end = rule->dlt_end;
1149 strcpy ((*rules)[0].std_name, rule->std_name);
1150 strcpy ((*rules)[0].dlt_name, rule->dlt_name);
1155 parse_offset (gchar **pos, gint32 *target)
1158 gchar *target_pos = *pos;
1161 while (**pos == '+' || **pos == '-' || **pos == ':' ||
1162 (**pos >= '0' && '9' >= **pos))
1165 buffer = g_strndup (target_pos, *pos - target_pos);
1166 ret = parse_constant_offset (buffer, target);
1173 parse_identifier_boundary (gchar **pos, TimeZoneDate *target)
1176 gchar *target_pos = *pos;
1179 while (**pos != ',' && **pos != '\0')
1181 buffer = g_strndup (target_pos, *pos - target_pos);
1182 ret = parse_tz_boundary (buffer, target);
1189 set_tz_name (gchar **pos, gchar *buffer, guint size)
1191 gchar *name_pos = *pos;
1194 /* Name is ASCII alpha (Is this necessarily true?) */
1195 while (g_ascii_isalpha (**pos))
1198 /* Name should be three or more alphabetic characters */
1199 if (*pos - name_pos < 3)
1202 memset (buffer, 0, NAME_SIZE);
1203 /* name_pos isn't 0-terminated, so we have to limit the length expressly */
1204 len = *pos - name_pos > size - 1 ? size - 1 : *pos - name_pos;
1205 strncpy (buffer, name_pos, len);
1210 parse_identifier_boundaries (gchar **pos, TimeZoneRule *tzr)
1212 if (*(*pos)++ != ',')
1216 if (!parse_identifier_boundary (pos, &(tzr->dlt_start)) || *(*pos)++ != ',')
1220 if (!parse_identifier_boundary (pos, &(tzr->dlt_end)))
1226 * Creates an array of TimeZoneRule from a TZ environment variable
1227 * type of identifier. Should free rules afterwards
1230 rules_from_identifier (const gchar *identifier,
1231 TimeZoneRule **rules)
1239 pos = (gchar*)identifier;
1240 memset (&tzr, 0, sizeof (tzr));
1241 /* Standard offset */
1242 if (!(set_tz_name (&pos, tzr.std_name, NAME_SIZE)) ||
1243 !parse_offset (&pos, &(tzr.std_offset)))
1247 return create_ruleset_from_rule (rules, &tzr);
1250 if (!(set_tz_name (&pos, tzr.dlt_name, NAME_SIZE)))
1252 parse_offset (&pos, &(tzr.dlt_offset));
1253 if (tzr.dlt_offset == 0) /* No daylight offset given, assume it's 1
1254 hour earlier that standard */
1255 tzr.dlt_offset = tzr.std_offset - 3600;
1258 /* Windows allows us to use the US DST boundaries if they're not given */
1261 guint rules_num = 0;
1263 /* Use US rules, Windows' default is Pacific Standard Time */
1264 if ((rules_num = rules_from_windows_time_zone ("Pacific Standard Time",
1267 for (i = 0; i < rules_num - 1; i++)
1269 (*rules)[i].std_offset = - tzr.std_offset;
1270 (*rules)[i].dlt_offset = - tzr.dlt_offset;
1271 strcpy ((*rules)[i].std_name, tzr.std_name);
1272 strcpy ((*rules)[i].dlt_name, tzr.dlt_name);
1283 /* Start and end required (format 2) */
1284 if (!parse_identifier_boundaries (&pos, &tzr))
1287 return create_ruleset_from_rule (rules, &tzr);
1290 /* Construction {{{1 */
1293 * @identifier: (allow-none): a timezone identifier
1295 * Creates a #GTimeZone corresponding to @identifier.
1297 * @identifier can either be an RFC3339/ISO 8601 time offset or
1298 * something that would pass as a valid value for the
1299 * <varname>TZ</varname> environment variable (including %NULL).
1301 * In Windows, @identifier can also be the unlocalized name of a time
1302 * zone for standard time, for example "Pacific Standard Time".
1304 * Valid RFC3339 time offsets are <literal>"Z"</literal> (for UTC) or
1305 * <literal>"±hh:mm"</literal>. ISO 8601 additionally specifies
1306 * <literal>"±hhmm"</literal> and <literal>"±hh"</literal>. Offsets are
1307 * time values to be added to Coordinated Universal Time (UTC) to get
1310 * In Unix, the <varname>TZ</varname> environment variable typically
1311 * corresponds to the name of a file in the zoneinfo database, or
1312 * string in "std offset [dst [offset],start[/time],end[/time]]"
1313 * (POSIX) format. There are no spaces in the specification. The
1314 * name of standard and daylight savings time zone must be three or more
1315 * alphabetic characters. Offsets are time values to be added to local
1316 * time to get Coordinated Universal Time (UTC) and should be
1317 * <literal>"[±]hh[[:]mm[:ss]]"</literal>. Dates are either
1318 * <literal>"Jn"</literal> (Julian day with n between 1 and 365, leap
1319 * years not counted), <literal>"n"</literal> (zero-based Julian day
1320 * with n between 0 and 365) or <literal>"Mm.w.d"</literal> (day d
1321 * (0 <= d <= 6) of week w (1 <= w <= 5) of month m (1 <= m <= 12), day
1322 * 0 is a Sunday). Times are in local wall clock time, the default is
1325 * In Windows, the "tzn[+|–]hh[:mm[:ss]][dzn]" format is used, but also
1326 * accepts POSIX format. The Windows format uses US rules for all time
1327 * zones; daylight savings time is 60 minutes behind the standard time
1328 * with date and time of change taken from Pacific Standard Time.
1329 * Offsets are time values to be added to the local time to get
1330 * Coordinated Universal Time (UTC).
1332 * g_time_zone_new_local() calls this function with the value of the
1333 * <varname>TZ</varname> environment variable. This function itself is
1334 * independent of the value of <varname>TZ</varname>, but if @identifier
1335 * is %NULL then <filename>/etc/localtime</filename> will be consulted
1336 * to discover the correct time zone on Unix and the registry will be
1337 * consulted or GetTimeZoneInformation() will be used to get the local
1338 * time zone on Windows.
1340 * If intervals are not available, only time zone rules from
1341 * <varname>TZ</varname> environment variable or other means, then they
1342 * will be computed from year 1900 to 2037. If the maximum year for the
1343 * rules is available and it is greater than 2037, then it will followed
1347 * url='http://tools.ietf.org/html/rfc3339#section-5.6'>RFC3339
1348 * §5.6</ulink> for a precise definition of valid RFC3339 time offsets
1349 * (the <varname>time-offset</varname> expansion) and ISO 8601 for the
1350 * full list of valid time offsets. See <ulink
1351 * url='http://www.gnu.org/s/libc/manual/html_node/TZ-Variable.html'>The
1352 * GNU C Library manual</ulink> for an explanation of the possible
1353 * values of the <varname>TZ</varname> environment variable. See <ulink
1354 * url='http://msdn.microsoft.com/en-us/library/ms912391%28v=winembedded.11%29.aspx'>
1355 * Microsoft Time Zone Index Values</ulink> for the list of time zones
1358 * You should release the return value by calling g_time_zone_unref()
1359 * when you are done with it.
1361 * Returns: the requested timezone
1366 g_time_zone_new (const gchar *identifier)
1368 GTimeZone *tz = NULL;
1369 TimeZoneRule *rules;
1372 G_LOCK (time_zones);
1373 if (time_zones == NULL)
1374 time_zones = g_hash_table_new (g_str_hash, g_str_equal);
1378 tz = g_hash_table_lookup (time_zones, identifier);
1381 g_atomic_int_inc (&tz->ref_count);
1382 G_UNLOCK (time_zones);
1387 tz = g_slice_new0 (GTimeZone);
1388 tz->name = g_strdup (identifier);
1391 zone_for_constant_offset (tz, identifier);
1393 if (tz->t_info == NULL &&
1394 (rules_num = rules_from_identifier (identifier, &rules)))
1396 init_zone_from_rules (tz, rules, rules_num);
1400 if (tz->t_info == NULL)
1403 GBytes *zoneinfo = zone_info_unix (identifier);
1405 zone_for_constant_offset (tz, "UTC");
1408 init_zone_from_iana_info (tz, zoneinfo);
1409 g_bytes_unref (zoneinfo);
1411 #elif defined (G_OS_WIN32)
1412 if ((rules_num = rules_from_windows_time_zone (identifier, &rules)))
1414 init_zone_from_rules (tz, rules, rules_num);
1419 if (tz->t_info == NULL)
1422 zone_for_constant_offset (tz, "UTC");
1425 TIME_ZONE_INFORMATION tzi;
1427 if (GetTimeZoneInformation (&tzi) != TIME_ZONE_ID_INVALID)
1429 rules = g_new0 (TimeZoneRule, 2);
1431 rule_from_windows_time_zone_info (&rules[0], &tzi);
1433 memset (rules[0].std_name, 0, NAME_SIZE);
1434 memset (rules[0].dlt_name, 0, NAME_SIZE);
1436 rules[0].start_year = MIN_TZYEAR;
1437 rules[1].start_year = MAX_TZYEAR;
1439 init_zone_from_rules (tz, rules, 2);
1447 if (tz->t_info != NULL)
1450 g_hash_table_insert (time_zones, tz->name, tz);
1452 g_atomic_int_inc (&tz->ref_count);
1453 G_UNLOCK (time_zones);
1459 * g_time_zone_new_utc:
1461 * Creates a #GTimeZone corresponding to UTC.
1463 * This is equivalent to calling g_time_zone_new() with a value like
1464 * "Z", "UTC", "+00", etc.
1466 * You should release the return value by calling g_time_zone_unref()
1467 * when you are done with it.
1469 * Returns: the universal timezone
1474 g_time_zone_new_utc (void)
1476 return g_time_zone_new ("UTC");
1480 * g_time_zone_new_local:
1482 * Creates a #GTimeZone corresponding to local time. The local time
1483 * zone may change between invocations to this function; for example,
1484 * if the system administrator changes it.
1486 * This is equivalent to calling g_time_zone_new() with the value of the
1487 * <varname>TZ</varname> environment variable (including the possibility
1490 * You should release the return value by calling g_time_zone_unref()
1491 * when you are done with it.
1493 * Returns: the local timezone
1498 g_time_zone_new_local (void)
1500 return g_time_zone_new (getenv ("TZ"));
1503 #define TRANSITION(n) g_array_index (tz->transitions, Transition, n)
1504 #define TRANSITION_INFO(n) g_array_index (tz->t_info, TransitionInfo, n)
1506 /* Internal helpers {{{1 */
1507 /* NB: Interval 0 is before the first transition, so there's no
1508 * transition structure to point to which TransitionInfo to
1509 * use. Rule-based zones are set up so that TI 0 is always standard
1510 * time (which is what's in effect before Daylight time got started
1511 * in the early 20th century), but IANA tzfiles don't follow that
1512 * convention. The tzfile documentation says to use the first
1513 * standard-time (i.e., non-DST) tinfo, so that's what we do.
1515 inline static const TransitionInfo*
1516 interval_info (GTimeZone *tz,
1520 g_return_val_if_fail (tz->t_info != NULL, NULL);
1521 if (interval && tz->transitions && interval <= tz->transitions->len)
1522 index = (TRANSITION(interval - 1)).info_index;
1525 for (index = 0; index < tz->t_info->len; index++)
1527 TransitionInfo *tzinfo = &(TRANSITION_INFO(index));
1528 if (!tzinfo->is_dst)
1534 return &(TRANSITION_INFO(index));
1537 inline static gint64
1538 interval_start (GTimeZone *tz,
1541 if (!interval || tz->transitions == NULL || tz->transitions->len == 0)
1543 if (interval > tz->transitions->len)
1544 interval = tz->transitions->len;
1545 return (TRANSITION(interval - 1)).time;
1548 inline static gint64
1549 interval_end (GTimeZone *tz,
1552 if (tz->transitions && interval < tz->transitions->len)
1553 return (TRANSITION(interval)).time - 1;
1557 inline static gint32
1558 interval_offset (GTimeZone *tz,
1561 g_return_val_if_fail (tz->t_info != NULL, 0);
1562 return interval_info (tz, interval)->gmt_offset;
1565 inline static gboolean
1566 interval_isdst (GTimeZone *tz,
1569 g_return_val_if_fail (tz->t_info != NULL, 0);
1570 return interval_info (tz, interval)->is_dst;
1574 inline static gboolean
1575 interval_isgmt (GTimeZone *tz,
1578 g_return_val_if_fail (tz->t_info != NULL, 0);
1579 return interval_info (tz, interval)->is_gmt;
1582 inline static gboolean
1583 interval_isstandard (GTimeZone *tz,
1586 return interval_info (tz, interval)->is_standard;
1589 inline static gchar*
1590 interval_abbrev (GTimeZone *tz,
1593 g_return_val_if_fail (tz->t_info != NULL, 0);
1594 return interval_info (tz, interval)->abbrev;
1597 inline static gint64
1598 interval_local_start (GTimeZone *tz,
1602 return interval_start (tz, interval) + interval_offset (tz, interval);
1607 inline static gint64
1608 interval_local_end (GTimeZone *tz,
1611 if (tz->transitions && interval < tz->transitions->len)
1612 return interval_end (tz, interval) + interval_offset (tz, interval);
1618 interval_valid (GTimeZone *tz,
1621 if ( tz->transitions == NULL)
1622 return interval == 0;
1623 return interval <= tz->transitions->len;
1626 /* g_time_zone_find_interval() {{{1 */
1629 * g_time_zone_adjust_time:
1631 * @type: the #GTimeType of @time_
1632 * @time_: a pointer to a number of seconds since January 1, 1970
1634 * Finds an interval within @tz that corresponds to the given @time_,
1635 * possibly adjusting @time_ if required to fit into an interval.
1636 * The meaning of @time_ depends on @type.
1638 * This function is similar to g_time_zone_find_interval(), with the
1639 * difference that it always succeeds (by making the adjustments
1642 * In any of the cases where g_time_zone_find_interval() succeeds then
1643 * this function returns the same value, without modifying @time_.
1645 * This function may, however, modify @time_ in order to deal with
1646 * non-existent times. If the non-existent local @time_ of 02:30 were
1647 * requested on March 14th 2010 in Toronto then this function would
1648 * adjust @time_ to be 03:00 and return the interval containing the
1651 * Returns: the interval containing @time_, never -1
1656 g_time_zone_adjust_time (GTimeZone *tz,
1663 if (tz->transitions == NULL)
1666 intervals = tz->transitions->len;
1668 /* find the interval containing *time UTC
1669 * TODO: this could be binary searched (or better) */
1670 for (i = 0; i <= intervals; i++)
1671 if (*time_ <= interval_end (tz, i))
1674 g_assert (interval_start (tz, i) <= *time_ && *time_ <= interval_end (tz, i));
1676 if (type != G_TIME_TYPE_UNIVERSAL)
1678 if (*time_ < interval_local_start (tz, i))
1679 /* if time came before the start of this interval... */
1683 /* if it's not in the previous interval... */
1684 if (*time_ > interval_local_end (tz, i))
1686 /* it doesn't exist. fast-forward it. */
1688 *time_ = interval_local_start (tz, i);
1692 else if (*time_ > interval_local_end (tz, i))
1693 /* if time came after the end of this interval... */
1697 /* if it's not in the next interval... */
1698 if (*time_ < interval_local_start (tz, i))
1699 /* it doesn't exist. fast-forward it. */
1700 *time_ = interval_local_start (tz, i);
1703 else if (interval_isdst (tz, i) != type)
1704 /* it's in this interval, but dst flag doesn't match.
1705 * check neighbours for a better fit. */
1707 if (i && *time_ <= interval_local_end (tz, i - 1))
1710 else if (i < intervals &&
1711 *time_ >= interval_local_start (tz, i + 1))
1720 * g_time_zone_find_interval:
1722 * @type: the #GTimeType of @time_
1723 * @time_: a number of seconds since January 1, 1970
1725 * Finds an the interval within @tz that corresponds to the given @time_.
1726 * The meaning of @time_ depends on @type.
1728 * If @type is %G_TIME_TYPE_UNIVERSAL then this function will always
1729 * succeed (since universal time is monotonic and continuous).
1731 * Otherwise @time_ is treated is local time. The distinction between
1732 * %G_TIME_TYPE_STANDARD and %G_TIME_TYPE_DAYLIGHT is ignored except in
1733 * the case that the given @time_ is ambiguous. In Toronto, for example,
1734 * 01:30 on November 7th 2010 occurred twice (once inside of daylight
1735 * savings time and the next, an hour later, outside of daylight savings
1736 * time). In this case, the different value of @type would result in a
1737 * different interval being returned.
1739 * It is still possible for this function to fail. In Toronto, for
1740 * example, 02:00 on March 14th 2010 does not exist (due to the leap
1741 * forward to begin daylight savings time). -1 is returned in that
1744 * Returns: the interval containing @time_, or -1 in case of failure
1749 g_time_zone_find_interval (GTimeZone *tz,
1756 if (tz->transitions == NULL)
1758 intervals = tz->transitions->len;
1759 for (i = 0; i <= intervals; i++)
1760 if (time_ <= interval_end (tz, i))
1763 if (type == G_TIME_TYPE_UNIVERSAL)
1766 if (time_ < interval_local_start (tz, i))
1768 if (time_ > interval_local_end (tz, --i))
1772 else if (time_ > interval_local_end (tz, i))
1774 if (time_ < interval_local_start (tz, ++i))
1778 else if (interval_isdst (tz, i) != type)
1780 if (i && time_ <= interval_local_end (tz, i - 1))
1783 else if (i < intervals && time_ >= interval_local_start (tz, i + 1))
1790 /* Public API accessors {{{1 */
1793 * g_time_zone_get_abbreviation:
1795 * @interval: an interval within the timezone
1797 * Determines the time zone abbreviation to be used during a particular
1798 * @interval of time in the time zone @tz.
1800 * For example, in Toronto this is currently "EST" during the winter
1801 * months and "EDT" during the summer months when daylight savings time
1804 * Returns: the time zone abbreviation, which belongs to @tz
1809 g_time_zone_get_abbreviation (GTimeZone *tz,
1812 g_return_val_if_fail (interval_valid (tz, (guint)interval), NULL);
1814 return interval_abbrev (tz, (guint)interval);
1818 * g_time_zone_get_offset:
1820 * @interval: an interval within the timezone
1822 * Determines the offset to UTC in effect during a particular @interval
1823 * of time in the time zone @tz.
1825 * The offset is the number of seconds that you add to UTC time to
1826 * arrive at local time for @tz (ie: negative numbers for time zones
1827 * west of GMT, positive numbers for east).
1829 * Returns: the number of seconds that should be added to UTC to get the
1835 g_time_zone_get_offset (GTimeZone *tz,
1838 g_return_val_if_fail (interval_valid (tz, (guint)interval), 0);
1840 return interval_offset (tz, (guint)interval);
1844 * g_time_zone_is_dst:
1846 * @interval: an interval within the timezone
1848 * Determines if daylight savings time is in effect during a particular
1849 * @interval of time in the time zone @tz.
1851 * Returns: %TRUE if daylight savings time is in effect
1856 g_time_zone_is_dst (GTimeZone *tz,
1859 g_return_val_if_fail (interval_valid (tz, interval), FALSE);
1861 if (tz->transitions == NULL)
1864 return interval_isdst (tz, (guint)interval);
1868 /* vim:set foldmethod=marker: */