1/*
2 * Copyright © 2010 Codethink Limited
3 *
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 2.1 of the License, or (at your option) any later version.
8 *
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.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with this library; if not, see <http://www.gnu.org/licenses/>.
16 *
17 * Author: Ryan Lortie <desrt@desrt.ca>
18 */
19
20/* Prologue {{{1 */
21
22#include "config.h"
23
24#include "gtimezone.h"
25
26#include <string.h>
27#include <stdlib.h>
28#include <signal.h>
29
30#include "gmappedfile.h"
31#include "gtestutils.h"
32#include "gfileutils.h"
33#include "gstrfuncs.h"
34#include "ghash.h"
35#include "gthread.h"
36#include "gbytes.h"
37#include "gslice.h"
38#include "gdatetime.h"
39#include "gdate.h"
40#include "genviron.h"
41
42#ifdef G_OS_WIN32
43
44#define STRICT
45#include <windows.h>
46#include <wchar.h>
47#endif
48
49/**
50 * SECTION:timezone
51 * @title: GTimeZone
52 * @short_description: a structure representing a time zone
53 * @see_also: #GDateTime
54 *
55 * #GTimeZone is a structure that represents a time zone, at no
56 * particular point in time. It is refcounted and immutable.
57 *
58 * Each time zone has an identifier (for example, ‘Europe/London’) which is
59 * platform dependent. See g_time_zone_new() for information on the identifier
60 * formats. The identifier of a time zone can be retrieved using
61 * g_time_zone_get_identifier().
62 *
63 * A time zone contains a number of intervals. Each interval has
64 * an abbreviation to describe it (for example, ‘PDT’), an offset to UTC and a
65 * flag indicating if the daylight savings time is in effect during that
66 * interval. A time zone always has at least one interval — interval 0. Note
67 * that interval abbreviations are not the same as time zone identifiers
68 * (apart from ‘UTC’), and cannot be passed to g_time_zone_new().
69 *
70 * Every UTC time is contained within exactly one interval, but a given
71 * local time may be contained within zero, one or two intervals (due to
72 * incontinuities associated with daylight savings time).
73 *
74 * An interval may refer to a specific period of time (eg: the duration
75 * of daylight savings time during 2010) or it may refer to many periods
76 * of time that share the same properties (eg: all periods of daylight
77 * savings time). It is also possible (usually for political reasons)
78 * that some properties (like the abbreviation) change between intervals
79 * without other properties changing.
80 *
81 * #GTimeZone is available since GLib 2.26.
82 */
83
84/**
85 * GTimeZone:
86 *
87 * #GTimeZone is an opaque structure whose members cannot be accessed
88 * directly.
89 *
90 * Since: 2.26
91 **/
92
93/* IANA zoneinfo file format {{{1 */
94
95/* unaligned */
96typedef struct { gchar bytes[8]; } gint64_be;
97typedef struct { gchar bytes[4]; } gint32_be;
98typedef struct { gchar bytes[4]; } guint32_be;
99
100static inline gint64 gint64_from_be (const gint64_be be) {
101 gint64 tmp; memcpy (dest: &tmp, src: &be, n: sizeof tmp); return GINT64_FROM_BE (tmp);
102}
103
104static inline gint32 gint32_from_be (const gint32_be be) {
105 gint32 tmp; memcpy (dest: &tmp, src: &be, n: sizeof tmp); return GINT32_FROM_BE (tmp);
106}
107
108static inline guint32 guint32_from_be (const guint32_be be) {
109 guint32 tmp; memcpy (dest: &tmp, src: &be, n: sizeof tmp); return GUINT32_FROM_BE (tmp);
110}
111
112/* The layout of an IANA timezone file header */
113struct tzhead
114{
115 gchar tzh_magic[4];
116 gchar tzh_version;
117 guchar tzh_reserved[15];
118
119 guint32_be tzh_ttisgmtcnt;
120 guint32_be tzh_ttisstdcnt;
121 guint32_be tzh_leapcnt;
122 guint32_be tzh_timecnt;
123 guint32_be tzh_typecnt;
124 guint32_be tzh_charcnt;
125};
126
127struct ttinfo
128{
129 gint32_be tt_gmtoff;
130 guint8 tt_isdst;
131 guint8 tt_abbrind;
132};
133
134/* A Transition Date structure for TZ Rules, an intermediate structure
135 for parsing MSWindows and Environment-variable time zones. It
136 Generalizes MSWindows's SYSTEMTIME struct.
137 */
138typedef struct
139{
140 gint year;
141 gint mon;
142 gint mday;
143 gint wday;
144 gint week;
145 gint32 offset; /* hour*3600 + min*60 + sec; can be negative. */
146} TimeZoneDate;
147
148/* POSIX Timezone abbreviations are typically 3 or 4 characters, but
149 Microsoft uses 32-character names. We'll use one larger to ensure
150 we have room for the terminating \0.
151 */
152#define NAME_SIZE 33
153
154/* A MSWindows-style time zone transition rule. Generalizes the
155 MSWindows TIME_ZONE_INFORMATION struct. Also used to compose time
156 zones from tzset-style identifiers.
157 */
158typedef struct
159{
160 gint start_year;
161 gint32 std_offset;
162 gint32 dlt_offset;
163 TimeZoneDate dlt_start;
164 TimeZoneDate dlt_end;
165 gchar std_name[NAME_SIZE];
166 gchar dlt_name[NAME_SIZE];
167} TimeZoneRule;
168
169/* GTimeZone's internal representation of a Daylight Savings (Summer)
170 time interval.
171 */
172typedef struct
173{
174 gint32 gmt_offset;
175 gboolean is_dst;
176 gchar *abbrev;
177} TransitionInfo;
178
179/* GTimeZone's representation of a transition time to or from Daylight
180 Savings (Summer) time and Standard time for the zone. */
181typedef struct
182{
183 gint64 time;
184 gint info_index;
185} Transition;
186
187/* GTimeZone structure */
188struct _GTimeZone
189{
190 gchar *name;
191 GArray *t_info; /* Array of TransitionInfo */
192 GArray *transitions; /* Array of Transition */
193 gint ref_count;
194};
195
196G_LOCK_DEFINE_STATIC (time_zones);
197static GHashTable/*<string?, GTimeZone>*/ *time_zones;
198G_LOCK_DEFINE_STATIC (tz_default);
199static GTimeZone *tz_default = NULL;
200G_LOCK_DEFINE_STATIC (tz_local);
201static GTimeZone *tz_local = NULL;
202
203#define MIN_TZYEAR 1916 /* Daylight Savings started in WWI */
204#define MAX_TZYEAR 2999 /* And it's not likely ever to go away, but
205 there's no point in getting carried
206 away. */
207
208#ifdef G_OS_UNIX
209static GTimeZone *parse_footertz (const gchar *, size_t);
210#endif
211
212/**
213 * g_time_zone_unref:
214 * @tz: a #GTimeZone
215 *
216 * Decreases the reference count on @tz.
217 *
218 * Since: 2.26
219 **/
220void
221g_time_zone_unref (GTimeZone *tz)
222{
223 int ref_count;
224
225again:
226 ref_count = g_atomic_int_get (&tz->ref_count);
227
228 g_assert (ref_count > 0);
229
230 if (ref_count == 1)
231 {
232 if (tz->name != NULL)
233 {
234 G_LOCK(time_zones);
235
236 /* someone else might have grabbed a ref in the meantime */
237 if G_UNLIKELY (g_atomic_int_get (&tz->ref_count) != 1)
238 {
239 G_UNLOCK(time_zones);
240 goto again;
241 }
242
243 if (time_zones != NULL)
244 g_hash_table_remove (hash_table: time_zones, key: tz->name);
245 G_UNLOCK(time_zones);
246 }
247
248 if (tz->t_info != NULL)
249 {
250 guint idx;
251 for (idx = 0; idx < tz->t_info->len; idx++)
252 {
253 TransitionInfo *info = &g_array_index (tz->t_info, TransitionInfo, idx);
254 g_free (mem: info->abbrev);
255 }
256 g_array_free (array: tz->t_info, TRUE);
257 }
258 if (tz->transitions != NULL)
259 g_array_free (array: tz->transitions, TRUE);
260 g_free (mem: tz->name);
261
262 g_slice_free (GTimeZone, tz);
263 }
264
265 else if G_UNLIKELY (!g_atomic_int_compare_and_exchange (&tz->ref_count,
266 ref_count,
267 ref_count - 1))
268 goto again;
269}
270
271/**
272 * g_time_zone_ref:
273 * @tz: a #GTimeZone
274 *
275 * Increases the reference count on @tz.
276 *
277 * Returns: a new reference to @tz.
278 *
279 * Since: 2.26
280 **/
281GTimeZone *
282g_time_zone_ref (GTimeZone *tz)
283{
284 g_assert (tz->ref_count > 0);
285
286 g_atomic_int_inc (&tz->ref_count);
287
288 return tz;
289}
290
291/* fake zoneinfo creation (for RFC3339/ISO 8601 timezones) {{{1 */
292/*
293 * parses strings of the form h or hh[[:]mm[[[:]ss]]] where:
294 * - h[h] is 0 to 24
295 * - mm is 00 to 59
296 * - ss is 00 to 59
297 * If RFC8536, TIME_ is a transition time sans sign,
298 * so colons are required before mm and ss, and hh can be up to 167.
299 * See Internet RFC 8536 section 3.3.1:
300 * https://tools.ietf.org/html/rfc8536#section-3.3.1
301 * and POSIX Base Definitions 8.3 TZ rule time:
302 * https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html#tag_08_03
303 */
304static gboolean
305parse_time (const gchar *time_,
306 gint32 *offset,
307 gboolean rfc8536)
308{
309 if (*time_ < '0' || '9' < *time_)
310 return FALSE;
311
312 *offset = 60 * 60 * (*time_++ - '0');
313
314 if (*time_ == '\0')
315 return TRUE;
316
317 if (*time_ != ':')
318 {
319 if (*time_ < '0' || '9' < *time_)
320 return FALSE;
321
322 *offset *= 10;
323 *offset += 60 * 60 * (*time_++ - '0');
324
325 if (rfc8536)
326 {
327 /* Internet RFC 8536 section 3.3.1 and POSIX 8.3 TZ together say
328 that a transition time must be of the form [+-]hh[:mm[:ss]] where
329 the hours part can range from -167 to 167. */
330 if ('0' <= *time_ && *time_ <= '9')
331 {
332 *offset *= 10;
333 *offset += 60 * 60 * (*time_++ - '0');
334 }
335 if (*offset > 167 * 60 * 60)
336 return FALSE;
337 }
338 else if (*offset > 24 * 60 * 60)
339 return FALSE;
340
341 if (*time_ == '\0')
342 return TRUE;
343 }
344
345 if (*time_ == ':')
346 time_++;
347 else if (rfc8536)
348 return FALSE;
349
350 if (*time_ < '0' || '5' < *time_)
351 return FALSE;
352
353 *offset += 10 * 60 * (*time_++ - '0');
354
355 if (*time_ < '0' || '9' < *time_)
356 return FALSE;
357
358 *offset += 60 * (*time_++ - '0');
359
360 if (*time_ == '\0')
361 return TRUE;
362
363 if (*time_ == ':')
364 time_++;
365 else if (rfc8536)
366 return FALSE;
367
368 if (*time_ < '0' || '5' < *time_)
369 return FALSE;
370
371 *offset += 10 * (*time_++ - '0');
372
373 if (*time_ < '0' || '9' < *time_)
374 return FALSE;
375
376 *offset += *time_++ - '0';
377
378 return *time_ == '\0';
379}
380
381static gboolean
382parse_constant_offset (const gchar *name,
383 gint32 *offset,
384 gboolean rfc8536)
385{
386 /* Internet RFC 8536 section 3.3.1 and POSIX 8.3 TZ together say
387 that a transition time must be numeric. */
388 if (!rfc8536 && g_strcmp0 (str1: name, str2: "UTC") == 0)
389 {
390 *offset = 0;
391 return TRUE;
392 }
393
394 if (*name >= '0' && '9' >= *name)
395 return parse_time (time_: name, offset, rfc8536);
396
397 switch (*name++)
398 {
399 case 'Z':
400 *offset = 0;
401 /* Internet RFC 8536 section 3.3.1 requires a numeric zone. */
402 return !rfc8536 && !*name;
403
404 case '+':
405 return parse_time (time_: name, offset, rfc8536);
406
407 case '-':
408 if (parse_time (time_: name, offset, rfc8536))
409 {
410 *offset = -*offset;
411 return TRUE;
412 }
413 else
414 return FALSE;
415
416 default:
417 return FALSE;
418 }
419}
420
421static void
422zone_for_constant_offset (GTimeZone *gtz, const gchar *name)
423{
424 gint32 offset;
425 TransitionInfo info;
426
427 if (name == NULL || !parse_constant_offset (name, offset: &offset, FALSE))
428 return;
429
430 info.gmt_offset = offset;
431 info.is_dst = FALSE;
432 info.abbrev = g_strdup (str: name);
433
434 gtz->name = g_strdup (str: name);
435 gtz->t_info = g_array_sized_new (FALSE, TRUE, element_size: sizeof (TransitionInfo), reserved_size: 1);
436 g_array_append_val (gtz->t_info, info);
437
438 /* Constant offset, no transitions */
439 gtz->transitions = NULL;
440}
441
442#ifdef G_OS_UNIX
443static gchar *
444zone_identifier_unix (void)
445{
446 gchar *resolved_identifier = NULL;
447 gsize prefix_len = 0;
448 gchar *canonical_path = NULL;
449 GError *read_link_err = NULL;
450 const gchar *tzdir;
451
452 /* Resolve the actual timezone pointed to by /etc/localtime. */
453 resolved_identifier = g_file_read_link (filename: "/etc/localtime", error: &read_link_err);
454 if (resolved_identifier == NULL)
455 {
456 gboolean not_a_symlink = g_error_matches (error: read_link_err,
457 G_FILE_ERROR,
458 code: G_FILE_ERROR_INVAL);
459 g_clear_error (err: &read_link_err);
460
461 /* Fallback to the content of /var/db/zoneinfo or /etc/timezone
462 * if /etc/localtime is not a symlink. /var/db/zoneinfo is
463 * where 'tzsetup' program on FreeBSD and DragonflyBSD stores
464 * the timezone chosen by the user. /etc/timezone is where user
465 * choice is expressed on Gentoo OpenRC and others. */
466 if (not_a_symlink && (g_file_get_contents (filename: "/var/db/zoneinfo",
467 contents: &resolved_identifier,
468 NULL, NULL) ||
469 g_file_get_contents (filename: "/etc/timezone",
470 contents: &resolved_identifier,
471 NULL, NULL)))
472 g_strchomp (string: resolved_identifier);
473 else
474 {
475 /* Error */
476 g_assert (resolved_identifier == NULL);
477 goto out;
478 }
479 }
480 else
481 {
482 /* Resolve relative path */
483 canonical_path = g_canonicalize_filename (filename: resolved_identifier, relative_to: "/etc");
484 g_free (mem: resolved_identifier);
485 resolved_identifier = g_steal_pointer (&canonical_path);
486 }
487
488 tzdir = g_getenv (variable: "TZDIR");
489 if (tzdir == NULL)
490 tzdir = "/usr/share/zoneinfo";
491
492 /* Strip the prefix and slashes if possible. */
493 if (g_str_has_prefix (str: resolved_identifier, prefix: tzdir))
494 {
495 prefix_len = strlen (s: tzdir);
496 while (*(resolved_identifier + prefix_len) == '/')
497 prefix_len++;
498 }
499
500 if (prefix_len > 0)
501 memmove (dest: resolved_identifier, src: resolved_identifier + prefix_len,
502 n: strlen (s: resolved_identifier) - prefix_len + 1 /* nul terminator */);
503
504 g_assert (resolved_identifier != NULL);
505
506out:
507 g_free (mem: canonical_path);
508
509 return resolved_identifier;
510}
511
512static GBytes*
513zone_info_unix (const gchar *identifier,
514 const gchar *resolved_identifier)
515{
516 gchar *filename = NULL;
517 GMappedFile *file = NULL;
518 GBytes *zoneinfo = NULL;
519 const gchar *tzdir;
520
521 tzdir = g_getenv (variable: "TZDIR");
522 if (tzdir == NULL)
523 tzdir = "/usr/share/zoneinfo";
524
525 /* identifier can be a relative or absolute path name;
526 if relative, it is interpreted starting from /usr/share/zoneinfo
527 while the POSIX standard says it should start with :,
528 glibc allows both syntaxes, so we should too */
529 if (identifier != NULL)
530 {
531 if (*identifier == ':')
532 identifier ++;
533
534 if (g_path_is_absolute (file_name: identifier))
535 filename = g_strdup (str: identifier);
536 else
537 filename = g_build_filename (first_element: tzdir, identifier, NULL);
538 }
539 else
540 {
541 if (resolved_identifier == NULL)
542 goto out;
543
544 filename = g_strdup (str: "/etc/localtime");
545 }
546
547 file = g_mapped_file_new (filename, FALSE, NULL);
548 if (file != NULL)
549 {
550 zoneinfo = g_bytes_new_with_free_func (data: g_mapped_file_get_contents (file),
551 size: g_mapped_file_get_length (file),
552 free_func: (GDestroyNotify)g_mapped_file_unref,
553 user_data: g_mapped_file_ref (file));
554 g_mapped_file_unref (file);
555 }
556
557 g_assert (resolved_identifier != NULL);
558
559out:
560 g_free (mem: filename);
561
562 return zoneinfo;
563}
564
565static void
566init_zone_from_iana_info (GTimeZone *gtz,
567 GBytes *zoneinfo,
568 gchar *identifier /* (transfer full) */)
569{
570 gsize size;
571 guint index;
572 guint32 time_count, type_count;
573 guint8 *tz_transitions, *tz_type_index, *tz_ttinfo;
574 guint8 *tz_abbrs;
575 gsize timesize = sizeof (gint32);
576 gconstpointer header_data = g_bytes_get_data (bytes: zoneinfo, size: &size);
577 const gchar *data = header_data;
578 const struct tzhead *header = header_data;
579 GTimeZone *footertz = NULL;
580 guint extra_time_count = 0, extra_type_count = 0;
581 gint64 last_explicit_transition_time;
582
583 g_return_if_fail (size >= sizeof (struct tzhead) &&
584 memcmp (header, "TZif", 4) == 0);
585
586 /* FIXME: Handle invalid TZif files better (Issue#1088). */
587
588 if (header->tzh_version >= '2')
589 {
590 /* Skip ahead to the newer 64-bit data if it's available. */
591 header = (const struct tzhead *)
592 (((const gchar *) (header + 1)) +
593 guint32_from_be(be: header->tzh_ttisgmtcnt) +
594 guint32_from_be(be: header->tzh_ttisstdcnt) +
595 8 * guint32_from_be(be: header->tzh_leapcnt) +
596 5 * guint32_from_be(be: header->tzh_timecnt) +
597 6 * guint32_from_be(be: header->tzh_typecnt) +
598 guint32_from_be(be: header->tzh_charcnt));
599 timesize = sizeof (gint64);
600 }
601 time_count = guint32_from_be(be: header->tzh_timecnt);
602 type_count = guint32_from_be(be: header->tzh_typecnt);
603
604 if (header->tzh_version >= '2')
605 {
606 const gchar *footer = (((const gchar *) (header + 1))
607 + guint32_from_be(be: header->tzh_ttisgmtcnt)
608 + guint32_from_be(be: header->tzh_ttisstdcnt)
609 + 12 * guint32_from_be(be: header->tzh_leapcnt)
610 + 9 * time_count
611 + 6 * type_count
612 + guint32_from_be(be: header->tzh_charcnt));
613 const gchar *footerlast;
614 size_t footerlen;
615 g_return_if_fail (footer <= data + size - 2 && footer[0] == '\n');
616 footerlast = memchr (s: footer + 1, c: '\n', n: data + size - (footer + 1));
617 g_return_if_fail (footerlast);
618 footerlen = footerlast + 1 - footer;
619 if (footerlen != 2)
620 {
621 footertz = parse_footertz (footer, footerlen);
622 g_return_if_fail (footertz);
623 extra_type_count = footertz->t_info->len;
624 extra_time_count = footertz->transitions->len;
625 }
626 }
627
628 tz_transitions = ((guint8 *) (header) + sizeof (*header));
629 tz_type_index = tz_transitions + timesize * time_count;
630 tz_ttinfo = tz_type_index + time_count;
631 tz_abbrs = tz_ttinfo + sizeof (struct ttinfo) * type_count;
632
633 gtz->name = g_steal_pointer (&identifier);
634 gtz->t_info = g_array_sized_new (FALSE, TRUE, element_size: sizeof (TransitionInfo),
635 reserved_size: type_count + extra_type_count);
636 gtz->transitions = g_array_sized_new (FALSE, TRUE, element_size: sizeof (Transition),
637 reserved_size: time_count + extra_time_count);
638
639 for (index = 0; index < type_count; index++)
640 {
641 TransitionInfo t_info;
642 struct ttinfo info = ((struct ttinfo*)tz_ttinfo)[index];
643 t_info.gmt_offset = gint32_from_be (be: info.tt_gmtoff);
644 t_info.is_dst = info.tt_isdst ? TRUE : FALSE;
645 t_info.abbrev = g_strdup (str: (gchar *) &tz_abbrs[info.tt_abbrind]);
646 g_array_append_val (gtz->t_info, t_info);
647 }
648
649 for (index = 0; index < time_count; index++)
650 {
651 Transition trans;
652 if (header->tzh_version >= '2')
653 trans.time = gint64_from_be (be: ((gint64_be*)tz_transitions)[index]);
654 else
655 trans.time = gint32_from_be (be: ((gint32_be*)tz_transitions)[index]);
656 last_explicit_transition_time = trans.time;
657 trans.info_index = tz_type_index[index];
658 g_assert (trans.info_index >= 0);
659 g_assert ((guint) trans.info_index < gtz->t_info->len);
660 g_array_append_val (gtz->transitions, trans);
661 }
662
663 if (footertz)
664 {
665 /* Append footer time types. Don't bother to coalesce
666 duplicates with existing time types. */
667 for (index = 0; index < extra_type_count; index++)
668 {
669 TransitionInfo t_info;
670 TransitionInfo *footer_t_info
671 = &g_array_index (footertz->t_info, TransitionInfo, index);
672 t_info.gmt_offset = footer_t_info->gmt_offset;
673 t_info.is_dst = footer_t_info->is_dst;
674 t_info.abbrev = g_steal_pointer (&footer_t_info->abbrev);
675 g_array_append_val (gtz->t_info, t_info);
676 }
677
678 /* Append footer transitions that follow the last explicit
679 transition. */
680 for (index = 0; index < extra_time_count; index++)
681 {
682 Transition *footer_transition
683 = &g_array_index (footertz->transitions, Transition, index);
684 if (time_count <= 0
685 || last_explicit_transition_time < footer_transition->time)
686 {
687 Transition trans;
688 trans.time = footer_transition->time;
689 trans.info_index = type_count + footer_transition->info_index;
690 g_array_append_val (gtz->transitions, trans);
691 }
692 }
693
694 g_time_zone_unref (tz: footertz);
695 }
696}
697
698#elif defined (G_OS_WIN32)
699
700static void
701copy_windows_systemtime (SYSTEMTIME *s_time, TimeZoneDate *tzdate)
702{
703 tzdate->offset
704 = s_time->wHour * 3600 + s_time->wMinute * 60 + s_time->wSecond;
705 tzdate->mon = s_time->wMonth;
706 tzdate->year = s_time->wYear;
707 tzdate->wday = s_time->wDayOfWeek ? s_time->wDayOfWeek : 7;
708
709 if (s_time->wYear)
710 {
711 tzdate->mday = s_time->wDay;
712 tzdate->wday = 0;
713 }
714 else
715 tzdate->week = s_time->wDay;
716}
717
718/* UTC = local time + bias while local time = UTC + offset */
719static gboolean
720rule_from_windows_time_zone_info (TimeZoneRule *rule,
721 TIME_ZONE_INFORMATION *tzi)
722{
723 gchar *std_name, *dlt_name;
724
725 std_name = g_utf16_to_utf8 ((gunichar2 *)tzi->StandardName, -1, NULL, NULL, NULL);
726 if (std_name == NULL)
727 return FALSE;
728
729 dlt_name = g_utf16_to_utf8 ((gunichar2 *)tzi->DaylightName, -1, NULL, NULL, NULL);
730 if (dlt_name == NULL)
731 {
732 g_free (std_name);
733 return FALSE;
734 }
735
736 /* Set offset */
737 if (tzi->StandardDate.wMonth)
738 {
739 rule->std_offset = -(tzi->Bias + tzi->StandardBias) * 60;
740 rule->dlt_offset = -(tzi->Bias + tzi->DaylightBias) * 60;
741 copy_windows_systemtime (&(tzi->DaylightDate), &(rule->dlt_start));
742
743 copy_windows_systemtime (&(tzi->StandardDate), &(rule->dlt_end));
744 }
745
746 else
747 {
748 rule->std_offset = -tzi->Bias * 60;
749 rule->dlt_start.mon = 0;
750 }
751 strncpy (rule->std_name, std_name, NAME_SIZE - 1);
752 strncpy (rule->dlt_name, dlt_name, NAME_SIZE - 1);
753
754 g_free (std_name);
755 g_free (dlt_name);
756
757 return TRUE;
758}
759
760static gchar*
761windows_default_tzname (void)
762{
763 const gunichar2 *subkey =
764 L"SYSTEM\\CurrentControlSet\\Control\\TimeZoneInformation";
765 HKEY key;
766 gchar *key_name = NULL;
767 gunichar2 *key_name_w = NULL;
768 if (RegOpenKeyExW (HKEY_LOCAL_MACHINE, subkey, 0,
769 KEY_QUERY_VALUE, &key) == ERROR_SUCCESS)
770 {
771 DWORD size = 0;
772 if (RegQueryValueExW (key, L"TimeZoneKeyName", NULL, NULL,
773 NULL, &size) == ERROR_SUCCESS)
774 {
775 key_name_w = g_malloc ((gint)size);
776
777 if (key_name_w == NULL ||
778 RegQueryValueExW (key, L"TimeZoneKeyName", NULL, NULL,
779 (LPBYTE)key_name_w, &size) != ERROR_SUCCESS)
780 {
781 g_free (key_name_w);
782 key_name = NULL;
783 }
784 else
785 key_name = g_utf16_to_utf8 (key_name_w, -1, NULL, NULL, NULL);
786 }
787 RegCloseKey (key);
788 }
789 return key_name;
790}
791
792typedef struct
793{
794 LONG Bias;
795 LONG StandardBias;
796 LONG DaylightBias;
797 SYSTEMTIME StandardDate;
798 SYSTEMTIME DaylightDate;
799} RegTZI;
800
801static void
802system_time_copy (SYSTEMTIME *orig, SYSTEMTIME *target)
803{
804 g_return_if_fail (orig != NULL);
805 g_return_if_fail (target != NULL);
806
807 target->wYear = orig->wYear;
808 target->wMonth = orig->wMonth;
809 target->wDayOfWeek = orig->wDayOfWeek;
810 target->wDay = orig->wDay;
811 target->wHour = orig->wHour;
812 target->wMinute = orig->wMinute;
813 target->wSecond = orig->wSecond;
814 target->wMilliseconds = orig->wMilliseconds;
815}
816
817static void
818register_tzi_to_tzi (RegTZI *reg, TIME_ZONE_INFORMATION *tzi)
819{
820 g_return_if_fail (reg != NULL);
821 g_return_if_fail (tzi != NULL);
822 tzi->Bias = reg->Bias;
823 system_time_copy (&(reg->StandardDate), &(tzi->StandardDate));
824 tzi->StandardBias = reg->StandardBias;
825 system_time_copy (&(reg->DaylightDate), &(tzi->DaylightDate));
826 tzi->DaylightBias = reg->DaylightBias;
827}
828
829static guint
830rules_from_windows_time_zone (const gchar *identifier,
831 const gchar *resolved_identifier,
832 TimeZoneRule **rules)
833{
834 HKEY key;
835 gchar *subkey = NULL;
836 gchar *subkey_dynamic = NULL;
837 const gchar *key_name;
838 const gchar *reg_key =
839 "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones\\";
840 TIME_ZONE_INFORMATION tzi;
841 DWORD size;
842 guint rules_num = 0;
843 RegTZI regtzi, regtzi_prev;
844 WCHAR winsyspath[MAX_PATH];
845 gunichar2 *subkey_w, *subkey_dynamic_w;
846
847 subkey_dynamic_w = NULL;
848
849 if (GetSystemDirectoryW (winsyspath, MAX_PATH) == 0)
850 return 0;
851
852 g_assert (rules != NULL);
853
854 *rules = NULL;
855 key_name = NULL;
856
857 if (!identifier)
858 key_name = resolved_identifier;
859 else
860 key_name = identifier;
861
862 if (!key_name)
863 return 0;
864
865 subkey = g_strconcat (reg_key, key_name, NULL);
866 subkey_w = g_utf8_to_utf16 (subkey, -1, NULL, NULL, NULL);
867 if (subkey_w == NULL)
868 goto utf16_conv_failed;
869
870 subkey_dynamic = g_strconcat (subkey, "\\Dynamic DST", NULL);
871 subkey_dynamic_w = g_utf8_to_utf16 (subkey_dynamic, -1, NULL, NULL, NULL);
872 if (subkey_dynamic_w == NULL)
873 goto utf16_conv_failed;
874
875 if (RegOpenKeyExW (HKEY_LOCAL_MACHINE, subkey_w, 0,
876 KEY_QUERY_VALUE, &key) != ERROR_SUCCESS)
877 goto utf16_conv_failed;
878
879 size = sizeof tzi.StandardName;
880
881 /* use RegLoadMUIStringW() to query MUI_Std from the registry if possible, otherwise
882 fallback to querying Std */
883 if (RegLoadMUIStringW (key, L"MUI_Std", tzi.StandardName,
884 size, &size, 0, winsyspath) != ERROR_SUCCESS)
885 {
886 size = sizeof tzi.StandardName;
887 if (RegQueryValueExW (key, L"Std", NULL, NULL,
888 (LPBYTE)&(tzi.StandardName), &size) != ERROR_SUCCESS)
889 goto registry_failed;
890 }
891
892 size = sizeof tzi.DaylightName;
893
894 /* use RegLoadMUIStringW() to query MUI_Dlt from the registry if possible, otherwise
895 fallback to querying Dlt */
896 if (RegLoadMUIStringW (key, L"MUI_Dlt", tzi.DaylightName,
897 size, &size, 0, winsyspath) != ERROR_SUCCESS)
898 {
899 size = sizeof tzi.DaylightName;
900 if (RegQueryValueExW (key, L"Dlt", NULL, NULL,
901 (LPBYTE)&(tzi.DaylightName), &size) != ERROR_SUCCESS)
902 goto registry_failed;
903 }
904
905 RegCloseKey (key);
906 if (RegOpenKeyExW (HKEY_LOCAL_MACHINE, subkey_dynamic_w, 0,
907 KEY_QUERY_VALUE, &key) == ERROR_SUCCESS)
908 {
909 DWORD first, last;
910 int year, i;
911 wchar_t s[12];
912
913 size = sizeof first;
914 if (RegQueryValueExW (key, L"FirstEntry", NULL, NULL,
915 (LPBYTE) &first, &size) != ERROR_SUCCESS)
916 goto registry_failed;
917
918 size = sizeof last;
919 if (RegQueryValueExW (key, L"LastEntry", NULL, NULL,
920 (LPBYTE) &last, &size) != ERROR_SUCCESS)
921 goto registry_failed;
922
923 rules_num = last - first + 2;
924 *rules = g_new0 (TimeZoneRule, rules_num);
925
926 for (year = first, i = 0; *rules != NULL && year <= last; year++)
927 {
928 gboolean failed = FALSE;
929 swprintf_s (s, 11, L"%d", year);
930
931 if (!failed)
932 {
933 size = sizeof regtzi;
934 if (RegQueryValueExW (key, s, NULL, NULL,
935 (LPBYTE) &regtzi, &size) != ERROR_SUCCESS)
936 failed = TRUE;
937 }
938
939 if (failed)
940 {
941 g_free (*rules);
942 *rules = NULL;
943 break;
944 }
945
946 if (year > first && memcmp (&regtzi_prev, &regtzi, sizeof regtzi) == 0)
947 continue;
948 else
949 memcpy (&regtzi_prev, &regtzi, sizeof regtzi);
950
951 register_tzi_to_tzi (&regtzi, &tzi);
952
953 if (!rule_from_windows_time_zone_info (&(*rules)[i], &tzi))
954 {
955 g_free (*rules);
956 *rules = NULL;
957 break;
958 }
959
960 (*rules)[i++].start_year = year;
961 }
962
963 rules_num = i + 1;
964
965registry_failed:
966 RegCloseKey (key);
967 }
968 else if (RegOpenKeyExW (HKEY_LOCAL_MACHINE, subkey_w, 0,
969 KEY_QUERY_VALUE, &key) == ERROR_SUCCESS)
970 {
971 size = sizeof regtzi;
972 if (RegQueryValueExW (key, L"TZI", NULL, NULL,
973 (LPBYTE) &regtzi, &size) == ERROR_SUCCESS)
974 {
975 rules_num = 2;
976 *rules = g_new0 (TimeZoneRule, 2);
977 register_tzi_to_tzi (&regtzi, &tzi);
978
979 if (!rule_from_windows_time_zone_info (&(*rules)[0], &tzi))
980 {
981 g_free (*rules);
982 *rules = NULL;
983 }
984 }
985
986 RegCloseKey (key);
987 }
988
989utf16_conv_failed:
990 g_free (subkey_dynamic_w);
991 g_free (subkey_dynamic);
992 g_free (subkey_w);
993 g_free (subkey);
994
995 if (*rules)
996 {
997 (*rules)[0].start_year = MIN_TZYEAR;
998 if ((*rules)[rules_num - 2].start_year < MAX_TZYEAR)
999 (*rules)[rules_num - 1].start_year = MAX_TZYEAR;
1000 else
1001 (*rules)[rules_num - 1].start_year = (*rules)[rules_num - 2].start_year + 1;
1002
1003 return rules_num;
1004 }
1005
1006 return 0;
1007}
1008
1009#endif
1010
1011static void
1012find_relative_date (TimeZoneDate *buffer)
1013{
1014 guint wday;
1015 GDate date;
1016 g_date_clear (date: &date, n_dates: 1);
1017 wday = buffer->wday;
1018
1019 /* Get last day if last is needed, first day otherwise */
1020 if (buffer->mon == 13 || buffer->mon == 14) /* Julian Date */
1021 {
1022 g_date_set_dmy (date: &date, day: 1, month: 1, y: buffer->year);
1023 if (wday >= 59 && buffer->mon == 13 && g_date_is_leap_year (year: buffer->year))
1024 g_date_add_days (date: &date, n_days: wday);
1025 else
1026 g_date_add_days (date: &date, n_days: wday - 1);
1027 buffer->mon = (int) g_date_get_month (date: &date);
1028 buffer->mday = (int) g_date_get_day (date: &date);
1029 buffer->wday = 0;
1030 }
1031 else /* M.W.D */
1032 {
1033 guint days;
1034 guint days_in_month = g_date_get_days_in_month (month: buffer->mon, year: buffer->year);
1035 GDateWeekday first_wday;
1036
1037 g_date_set_dmy (date: &date, day: 1, month: buffer->mon, y: buffer->year);
1038 first_wday = g_date_get_weekday (date: &date);
1039
1040 if (first_wday > wday)
1041 ++(buffer->week);
1042 /* week is 1 <= w <= 5, we need 0-based */
1043 days = 7 * (buffer->week - 1) + wday - first_wday;
1044
1045 /* "days" is a 0-based offset from the 1st of the month.
1046 * Adding days == days_in_month would bring us into the next month,
1047 * hence the ">=" instead of just ">".
1048 */
1049 while (days >= days_in_month)
1050 days -= 7;
1051
1052 g_date_add_days (date: &date, n_days: days);
1053
1054 buffer->mday = g_date_get_day (date: &date);
1055 }
1056}
1057
1058/* Offset is previous offset of local time. Returns 0 if month is 0 */
1059static gint64
1060boundary_for_year (TimeZoneDate *boundary,
1061 gint year,
1062 gint32 offset)
1063{
1064 TimeZoneDate buffer;
1065 GDate date;
1066 const guint64 unix_epoch_start = 719163L;
1067 const guint64 seconds_per_day = 86400L;
1068
1069 if (!boundary->mon)
1070 return 0;
1071 buffer = *boundary;
1072
1073 if (boundary->year == 0)
1074 {
1075 buffer.year = year;
1076
1077 if (buffer.wday)
1078 find_relative_date (buffer: &buffer);
1079 }
1080
1081 g_assert (buffer.year == year);
1082 g_date_clear (date: &date, n_dates: 1);
1083 g_date_set_dmy (date: &date, day: buffer.mday, month: buffer.mon, y: buffer.year);
1084 return ((g_date_get_julian (date: &date) - unix_epoch_start) * seconds_per_day +
1085 buffer.offset - offset);
1086}
1087
1088static void
1089fill_transition_info_from_rule (TransitionInfo *info,
1090 TimeZoneRule *rule,
1091 gboolean is_dst)
1092{
1093 gint offset = is_dst ? rule->dlt_offset : rule->std_offset;
1094 gchar *name = is_dst ? rule->dlt_name : rule->std_name;
1095
1096 info->gmt_offset = offset;
1097 info->is_dst = is_dst;
1098
1099 if (name)
1100 info->abbrev = g_strdup (str: name);
1101
1102 else
1103 info->abbrev = g_strdup_printf (format: "%+03d%02d",
1104 (int) offset / 3600,
1105 (int) abs (x: offset / 60) % 60);
1106}
1107
1108static void
1109init_zone_from_rules (GTimeZone *gtz,
1110 TimeZoneRule *rules,
1111 guint rules_num,
1112 gchar *identifier /* (transfer full) */)
1113{
1114 guint type_count = 0, trans_count = 0, info_index = 0;
1115 guint ri; /* rule index */
1116 gboolean skip_first_std_trans = TRUE;
1117 gint32 last_offset;
1118
1119 type_count = 0;
1120 trans_count = 0;
1121
1122 /* Last rule only contains max year */
1123 for (ri = 0; ri < rules_num - 1; ri++)
1124 {
1125 if (rules[ri].dlt_start.mon || rules[ri].dlt_end.mon)
1126 {
1127 guint rulespan = (rules[ri + 1].start_year - rules[ri].start_year);
1128 guint transitions = rules[ri].dlt_start.mon > 0 ? 1 : 0;
1129 transitions += rules[ri].dlt_end.mon > 0 ? 1 : 0;
1130 type_count += rules[ri].dlt_start.mon > 0 ? 2 : 1;
1131 trans_count += transitions * rulespan;
1132 }
1133 else
1134 type_count++;
1135 }
1136
1137 gtz->name = g_steal_pointer (&identifier);
1138 gtz->t_info = g_array_sized_new (FALSE, TRUE, element_size: sizeof (TransitionInfo), reserved_size: type_count);
1139 gtz->transitions = g_array_sized_new (FALSE, TRUE, element_size: sizeof (Transition), reserved_size: trans_count);
1140
1141 last_offset = rules[0].std_offset;
1142
1143 for (ri = 0; ri < rules_num - 1; ri++)
1144 {
1145 if ((rules[ri].std_offset || rules[ri].dlt_offset) &&
1146 rules[ri].dlt_start.mon == 0 && rules[ri].dlt_end.mon == 0)
1147 {
1148 TransitionInfo std_info;
1149 /* Standard */
1150 fill_transition_info_from_rule (info: &std_info, rule: &(rules[ri]), FALSE);
1151 g_array_append_val (gtz->t_info, std_info);
1152
1153 if (ri > 0 &&
1154 ((rules[ri - 1].dlt_start.mon > 12 &&
1155 rules[ri - 1].dlt_start.wday > rules[ri - 1].dlt_end.wday) ||
1156 rules[ri - 1].dlt_start.mon > rules[ri - 1].dlt_end.mon))
1157 {
1158 /* The previous rule was a southern hemisphere rule that
1159 starts the year with DST, so we need to add a
1160 transition to return to standard time */
1161 guint year = rules[ri].start_year;
1162 gint64 std_time = boundary_for_year (boundary: &rules[ri].dlt_end,
1163 year, offset: last_offset);
1164 Transition std_trans = {std_time, info_index};
1165 g_array_append_val (gtz->transitions, std_trans);
1166
1167 }
1168 last_offset = rules[ri].std_offset;
1169 ++info_index;
1170 skip_first_std_trans = TRUE;
1171 }
1172 else
1173 {
1174 const guint start_year = rules[ri].start_year;
1175 const guint end_year = rules[ri + 1].start_year;
1176 gboolean dlt_first;
1177 guint year;
1178 TransitionInfo std_info, dlt_info;
1179 if (rules[ri].dlt_start.mon > 12)
1180 dlt_first = rules[ri].dlt_start.wday > rules[ri].dlt_end.wday;
1181 else
1182 dlt_first = rules[ri].dlt_start.mon > rules[ri].dlt_end.mon;
1183 /* Standard rules are always even, because before the first
1184 transition is always standard time, and 0 is even. */
1185 fill_transition_info_from_rule (info: &std_info, rule: &(rules[ri]), FALSE);
1186 fill_transition_info_from_rule (info: &dlt_info, rule: &(rules[ri]), TRUE);
1187
1188 g_array_append_val (gtz->t_info, std_info);
1189 g_array_append_val (gtz->t_info, dlt_info);
1190
1191 /* Transition dates. We hope that a year which ends daylight
1192 time in a southern-hemisphere country (i.e., one that
1193 begins the year in daylight time) will include a rule
1194 which has only a dlt_end. */
1195 for (year = start_year; year < end_year; year++)
1196 {
1197 gint32 dlt_offset = (dlt_first ? last_offset :
1198 rules[ri].dlt_offset);
1199 gint32 std_offset = (dlt_first ? rules[ri].std_offset :
1200 last_offset);
1201 /* NB: boundary_for_year returns 0 if mon == 0 */
1202 gint64 std_time = boundary_for_year (boundary: &rules[ri].dlt_end,
1203 year, offset: dlt_offset);
1204 gint64 dlt_time = boundary_for_year (boundary: &rules[ri].dlt_start,
1205 year, offset: std_offset);
1206 Transition std_trans = {std_time, info_index};
1207 Transition dlt_trans = {dlt_time, info_index + 1};
1208 last_offset = (dlt_first ? rules[ri].dlt_offset :
1209 rules[ri].std_offset);
1210 if (dlt_first)
1211 {
1212 if (skip_first_std_trans)
1213 skip_first_std_trans = FALSE;
1214 else if (std_time)
1215 g_array_append_val (gtz->transitions, std_trans);
1216 if (dlt_time)
1217 g_array_append_val (gtz->transitions, dlt_trans);
1218 }
1219 else
1220 {
1221 if (dlt_time)
1222 g_array_append_val (gtz->transitions, dlt_trans);
1223 if (std_time)
1224 g_array_append_val (gtz->transitions, std_trans);
1225 }
1226 }
1227
1228 info_index += 2;
1229 }
1230 }
1231 if (ri > 0 &&
1232 ((rules[ri - 1].dlt_start.mon > 12 &&
1233 rules[ri - 1].dlt_start.wday > rules[ri - 1].dlt_end.wday) ||
1234 rules[ri - 1].dlt_start.mon > rules[ri - 1].dlt_end.mon))
1235 {
1236 /* The previous rule was a southern hemisphere rule that
1237 starts the year with DST, so we need to add a
1238 transition to return to standard time */
1239 TransitionInfo info;
1240 guint year = rules[ri].start_year;
1241 Transition trans;
1242 fill_transition_info_from_rule (info: &info, rule: &(rules[ri - 1]), FALSE);
1243 g_array_append_val (gtz->t_info, info);
1244 trans.time = boundary_for_year (boundary: &rules[ri - 1].dlt_end,
1245 year, offset: last_offset);
1246 trans.info_index = info_index;
1247 g_array_append_val (gtz->transitions, trans);
1248 }
1249}
1250
1251/*
1252 * parses date[/time] for parsing TZ environment variable
1253 *
1254 * date is either Mm.w.d, Jn or N
1255 * - m is 1 to 12
1256 * - w is 1 to 5
1257 * - d is 0 to 6
1258 * - n is 1 to 365
1259 * - N is 0 to 365
1260 *
1261 * time is either h or hh[[:]mm[[[:]ss]]]
1262 * - h[h] is 0 to 24
1263 * - mm is 00 to 59
1264 * - ss is 00 to 59
1265 */
1266static gboolean
1267parse_mwd_boundary (gchar **pos, TimeZoneDate *boundary)
1268{
1269 gint month, week, day;
1270
1271 if (**pos == '\0' || **pos < '0' || '9' < **pos)
1272 return FALSE;
1273
1274 month = *(*pos)++ - '0';
1275
1276 if ((month == 1 && **pos >= '0' && '2' >= **pos) ||
1277 (month == 0 && **pos >= '0' && '9' >= **pos))
1278 {
1279 month *= 10;
1280 month += *(*pos)++ - '0';
1281 }
1282
1283 if (*(*pos)++ != '.' || month == 0)
1284 return FALSE;
1285
1286 if (**pos == '\0' || **pos < '1' || '5' < **pos)
1287 return FALSE;
1288
1289 week = *(*pos)++ - '0';
1290
1291 if (*(*pos)++ != '.')
1292 return FALSE;
1293
1294 if (**pos == '\0' || **pos < '0' || '6' < **pos)
1295 return FALSE;
1296
1297 day = *(*pos)++ - '0';
1298
1299 if (!day)
1300 day += 7;
1301
1302 boundary->year = 0;
1303 boundary->mon = month;
1304 boundary->week = week;
1305 boundary->wday = day;
1306 return TRUE;
1307}
1308
1309/*
1310 * This parses two slightly different ways of specifying
1311 * the Julian day:
1312 *
1313 * - ignore_leap == TRUE
1314 *
1315 * Jn This specifies the Julian day with n between 1 and 365. Leap days
1316 * are not counted. In this format, February 29 can't be represented;
1317 * February 28 is day 59, and March 1 is always day 60.
1318 *
1319 * - ignore_leap == FALSE
1320 *
1321 * n This specifies the zero-based Julian day with n between 0 and 365.
1322 * February 29 is counted in leap years.
1323 */
1324static gboolean
1325parse_julian_boundary (gchar** pos, TimeZoneDate *boundary,
1326 gboolean ignore_leap)
1327{
1328 gint day = 0;
1329 GDate date;
1330
1331 while (**pos >= '0' && '9' >= **pos)
1332 {
1333 day *= 10;
1334 day += *(*pos)++ - '0';
1335 }
1336
1337 if (ignore_leap)
1338 {
1339 if (day < 1 || 365 < day)
1340 return FALSE;
1341 if (day >= 59)
1342 day++;
1343 }
1344 else
1345 {
1346 if (day < 0 || 365 < day)
1347 return FALSE;
1348 /* GDate wants day in range 1->366 */
1349 day++;
1350 }
1351
1352 g_date_clear (date: &date, n_dates: 1);
1353 g_date_set_julian (date: &date, julian_date: day);
1354 boundary->year = 0;
1355 boundary->mon = (int) g_date_get_month (date: &date);
1356 boundary->mday = (int) g_date_get_day (date: &date);
1357 boundary->wday = 0;
1358
1359 return TRUE;
1360}
1361
1362static gboolean
1363parse_tz_boundary (const gchar *identifier,
1364 TimeZoneDate *boundary)
1365{
1366 gchar *pos;
1367
1368 pos = (gchar*)identifier;
1369 /* Month-week-weekday */
1370 if (*pos == 'M')
1371 {
1372 ++pos;
1373 if (!parse_mwd_boundary (pos: &pos, boundary))
1374 return FALSE;
1375 }
1376 /* Julian date which ignores Feb 29 in leap years */
1377 else if (*pos == 'J')
1378 {
1379 ++pos;
1380 if (!parse_julian_boundary (pos: &pos, boundary, TRUE))
1381 return FALSE ;
1382 }
1383 /* Julian date which counts Feb 29 in leap years */
1384 else if (*pos >= '0' && '9' >= *pos)
1385 {
1386 if (!parse_julian_boundary (pos: &pos, boundary, FALSE))
1387 return FALSE;
1388 }
1389 else
1390 return FALSE;
1391
1392 /* Time */
1393
1394 if (*pos == '/')
1395 return parse_constant_offset (name: pos + 1, offset: &boundary->offset, TRUE);
1396 else
1397 {
1398 boundary->offset = 2 * 60 * 60;
1399 return *pos == '\0';
1400 }
1401}
1402
1403static guint
1404create_ruleset_from_rule (TimeZoneRule **rules, TimeZoneRule *rule)
1405{
1406 *rules = g_new0 (TimeZoneRule, 2);
1407
1408 (*rules)[0].start_year = MIN_TZYEAR;
1409 (*rules)[1].start_year = MAX_TZYEAR;
1410
1411 (*rules)[0].std_offset = -rule->std_offset;
1412 (*rules)[0].dlt_offset = -rule->dlt_offset;
1413 (*rules)[0].dlt_start = rule->dlt_start;
1414 (*rules)[0].dlt_end = rule->dlt_end;
1415 strcpy (dest: (*rules)[0].std_name, src: rule->std_name);
1416 strcpy (dest: (*rules)[0].dlt_name, src: rule->dlt_name);
1417 return 2;
1418}
1419
1420static gboolean
1421parse_offset (gchar **pos, gint32 *target)
1422{
1423 gchar *buffer;
1424 gchar *target_pos = *pos;
1425 gboolean ret;
1426
1427 while (**pos == '+' || **pos == '-' || **pos == ':' ||
1428 (**pos >= '0' && '9' >= **pos))
1429 ++(*pos);
1430
1431 buffer = g_strndup (str: target_pos, n: *pos - target_pos);
1432 ret = parse_constant_offset (name: buffer, offset: target, FALSE);
1433 g_free (mem: buffer);
1434
1435 return ret;
1436}
1437
1438static gboolean
1439parse_identifier_boundary (gchar **pos, TimeZoneDate *target)
1440{
1441 gchar *buffer;
1442 gchar *target_pos = *pos;
1443 gboolean ret;
1444
1445 while (**pos != ',' && **pos != '\0')
1446 ++(*pos);
1447 buffer = g_strndup (str: target_pos, n: *pos - target_pos);
1448 ret = parse_tz_boundary (identifier: buffer, boundary: target);
1449 g_free (mem: buffer);
1450
1451 return ret;
1452}
1453
1454static gboolean
1455set_tz_name (gchar **pos, gchar *buffer, guint size)
1456{
1457 gboolean quoted = **pos == '<';
1458 gchar *name_pos = *pos;
1459 guint len;
1460
1461 if (quoted)
1462 {
1463 name_pos++;
1464 do
1465 ++(*pos);
1466 while (g_ascii_isalnum (**pos) || **pos == '-' || **pos == '+');
1467 if (**pos != '>')
1468 return FALSE;
1469 }
1470 else
1471 while (g_ascii_isalpha (**pos))
1472 ++(*pos);
1473
1474 /* Name should be three or more characters */
1475 /* FIXME: Should return FALSE if the name is too long.
1476 This should simplify code later in this function. */
1477 if (*pos - name_pos < 3)
1478 return FALSE;
1479
1480 memset (s: buffer, c: 0, n: size);
1481 /* name_pos isn't 0-terminated, so we have to limit the length expressly */
1482 len = *pos - name_pos > size - 1 ? size - 1 : *pos - name_pos;
1483 strncpy (dest: buffer, src: name_pos, n: len);
1484 *pos += quoted;
1485 return TRUE;
1486}
1487
1488static gboolean
1489parse_identifier_boundaries (gchar **pos, TimeZoneRule *tzr)
1490{
1491 if (*(*pos)++ != ',')
1492 return FALSE;
1493
1494 /* Start date */
1495 if (!parse_identifier_boundary (pos, target: &(tzr->dlt_start)) || *(*pos)++ != ',')
1496 return FALSE;
1497
1498 /* End date */
1499 if (!parse_identifier_boundary (pos, target: &(tzr->dlt_end)))
1500 return FALSE;
1501 return TRUE;
1502}
1503
1504/*
1505 * Creates an array of TimeZoneRule from a TZ environment variable
1506 * type of identifier. Should free rules afterwards
1507 */
1508static guint
1509rules_from_identifier (const gchar *identifier,
1510 TimeZoneRule **rules)
1511{
1512 gchar *pos;
1513 TimeZoneRule tzr;
1514
1515 g_assert (rules != NULL);
1516
1517 *rules = NULL;
1518
1519 if (!identifier)
1520 return 0;
1521
1522 pos = (gchar*)identifier;
1523 memset (s: &tzr, c: 0, n: sizeof (tzr));
1524 /* Standard offset */
1525 if (!(set_tz_name (pos: &pos, buffer: tzr.std_name, NAME_SIZE)) ||
1526 !parse_offset (pos: &pos, target: &(tzr.std_offset)))
1527 return 0;
1528
1529 if (*pos == 0)
1530 {
1531 return create_ruleset_from_rule (rules, rule: &tzr);
1532 }
1533
1534 /* Format 2 */
1535 if (!(set_tz_name (pos: &pos, buffer: tzr.dlt_name, NAME_SIZE)))
1536 return 0;
1537 parse_offset (pos: &pos, target: &(tzr.dlt_offset));
1538 if (tzr.dlt_offset == 0) /* No daylight offset given, assume it's 1
1539 hour earlier that standard */
1540 tzr.dlt_offset = tzr.std_offset - 3600;
1541 if (*pos == '\0')
1542#ifdef G_OS_WIN32
1543 /* Windows allows us to use the US DST boundaries if they're not given */
1544 {
1545 int i;
1546 guint rules_num = 0;
1547
1548 /* Use US rules, Windows' default is Pacific Standard Time */
1549 if ((rules_num = rules_from_windows_time_zone ("Pacific Standard Time",
1550 NULL,
1551 rules)))
1552 {
1553 for (i = 0; i < rules_num - 1; i++)
1554 {
1555 (*rules)[i].std_offset = - tzr.std_offset;
1556 (*rules)[i].dlt_offset = - tzr.dlt_offset;
1557 strcpy ((*rules)[i].std_name, tzr.std_name);
1558 strcpy ((*rules)[i].dlt_name, tzr.dlt_name);
1559 }
1560
1561 return rules_num;
1562 }
1563 else
1564 return 0;
1565 }
1566#else
1567 return 0;
1568#endif
1569 /* Start and end required (format 2) */
1570 if (!parse_identifier_boundaries (pos: &pos, tzr: &tzr))
1571 return 0;
1572
1573 return create_ruleset_from_rule (rules, rule: &tzr);
1574}
1575
1576#ifdef G_OS_UNIX
1577static GTimeZone *
1578parse_footertz (const gchar *footer, size_t footerlen)
1579{
1580 gchar *tzstring = g_strndup (str: footer + 1, n: footerlen - 2);
1581 GTimeZone *footertz = NULL;
1582
1583 /* FIXME: The allocation for tzstring could be avoided by
1584 passing a gsize identifier_len argument to rules_from_identifier
1585 and changing the code in that function to stop assuming that
1586 identifier is nul-terminated. */
1587 TimeZoneRule *rules;
1588 guint rules_num = rules_from_identifier (identifier: tzstring, rules: &rules);
1589
1590 g_free (mem: tzstring);
1591 if (rules_num > 1)
1592 {
1593 footertz = g_slice_new0 (GTimeZone);
1594 init_zone_from_rules (gtz: footertz, rules, rules_num, NULL);
1595 footertz->ref_count++;
1596 }
1597 g_free (mem: rules);
1598 return footertz;
1599}
1600#endif
1601
1602/* Construction {{{1 */
1603/**
1604 * g_time_zone_new:
1605 * @identifier: (nullable): a timezone identifier
1606 *
1607 * A version of g_time_zone_new_identifier() which returns the UTC time zone
1608 * if @identifier could not be parsed or loaded.
1609 *
1610 * If you need to check whether @identifier was loaded successfully, use
1611 * g_time_zone_new_identifier().
1612 *
1613 * Returns: (transfer full) (not nullable): the requested timezone
1614 * Deprecated: 2.68: Use g_time_zone_new_identifier() instead, as it provides
1615 * error reporting. Change your code to handle a potentially %NULL return
1616 * value.
1617 *
1618 * Since: 2.26
1619 **/
1620GTimeZone *
1621g_time_zone_new (const gchar *identifier)
1622{
1623 GTimeZone *tz = g_time_zone_new_identifier (identifier);
1624
1625 /* Always fall back to UTC. */
1626 if (tz == NULL)
1627 tz = g_time_zone_new_utc ();
1628
1629 g_assert (tz != NULL);
1630
1631 return g_steal_pointer (&tz);
1632}
1633
1634/**
1635 * g_time_zone_new_identifier:
1636 * @identifier: (nullable): a timezone identifier
1637 *
1638 * Creates a #GTimeZone corresponding to @identifier. If @identifier cannot be
1639 * parsed or loaded, %NULL is returned.
1640 *
1641 * @identifier can either be an RFC3339/ISO 8601 time offset or
1642 * something that would pass as a valid value for the `TZ` environment
1643 * variable (including %NULL).
1644 *
1645 * In Windows, @identifier can also be the unlocalized name of a time
1646 * zone for standard time, for example "Pacific Standard Time".
1647 *
1648 * Valid RFC3339 time offsets are `"Z"` (for UTC) or
1649 * `"±hh:mm"`. ISO 8601 additionally specifies
1650 * `"±hhmm"` and `"±hh"`. Offsets are
1651 * time values to be added to Coordinated Universal Time (UTC) to get
1652 * the local time.
1653 *
1654 * In UNIX, the `TZ` environment variable typically corresponds
1655 * to the name of a file in the zoneinfo database, an absolute path to a file
1656 * somewhere else, or a string in
1657 * "std offset [dst [offset],start[/time],end[/time]]" (POSIX) format.
1658 * There are no spaces in the specification. The name of standard
1659 * and daylight savings time zone must be three or more alphabetic
1660 * characters. Offsets are time values to be added to local time to
1661 * get Coordinated Universal Time (UTC) and should be
1662 * `"[±]hh[[:]mm[:ss]]"`. Dates are either
1663 * `"Jn"` (Julian day with n between 1 and 365, leap
1664 * years not counted), `"n"` (zero-based Julian day
1665 * with n between 0 and 365) or `"Mm.w.d"` (day d
1666 * (0 <= d <= 6) of week w (1 <= w <= 5) of month m (1 <= m <= 12), day
1667 * 0 is a Sunday). Times are in local wall clock time, the default is
1668 * 02:00:00.
1669 *
1670 * In Windows, the "tzn[+|–]hh[:mm[:ss]][dzn]" format is used, but also
1671 * accepts POSIX format. The Windows format uses US rules for all time
1672 * zones; daylight savings time is 60 minutes behind the standard time
1673 * with date and time of change taken from Pacific Standard Time.
1674 * Offsets are time values to be added to the local time to get
1675 * Coordinated Universal Time (UTC).
1676 *
1677 * g_time_zone_new_local() calls this function with the value of the
1678 * `TZ` environment variable. This function itself is independent of
1679 * the value of `TZ`, but if @identifier is %NULL then `/etc/localtime`
1680 * will be consulted to discover the correct time zone on UNIX and the
1681 * registry will be consulted or GetTimeZoneInformation() will be used
1682 * to get the local time zone on Windows.
1683 *
1684 * If intervals are not available, only time zone rules from `TZ`
1685 * environment variable or other means, then they will be computed
1686 * from year 1900 to 2037. If the maximum year for the rules is
1687 * available and it is greater than 2037, then it will followed
1688 * instead.
1689 *
1690 * See
1691 * [RFC3339 §5.6](http://tools.ietf.org/html/rfc3339#section-5.6)
1692 * for a precise definition of valid RFC3339 time offsets
1693 * (the `time-offset` expansion) and ISO 8601 for the
1694 * full list of valid time offsets. See
1695 * [The GNU C Library manual](http://www.gnu.org/s/libc/manual/html_node/TZ-Variable.html)
1696 * for an explanation of the possible
1697 * values of the `TZ` environment variable. See
1698 * [Microsoft Time Zone Index Values](http://msdn.microsoft.com/en-us/library/ms912391%28v=winembedded.11%29.aspx)
1699 * for the list of time zones on Windows.
1700 *
1701 * You should release the return value by calling g_time_zone_unref()
1702 * when you are done with it.
1703 *
1704 * Returns: (transfer full) (nullable): the requested timezone, or %NULL on
1705 * failure
1706 * Since: 2.68
1707 */
1708GTimeZone *
1709g_time_zone_new_identifier (const gchar *identifier)
1710{
1711 GTimeZone *tz = NULL;
1712 TimeZoneRule *rules;
1713 gint rules_num;
1714 gchar *resolved_identifier = NULL;
1715
1716 if (identifier)
1717 {
1718 G_LOCK (time_zones);
1719 if (time_zones == NULL)
1720 time_zones = g_hash_table_new (hash_func: g_str_hash, key_equal_func: g_str_equal);
1721
1722 tz = g_hash_table_lookup (hash_table: time_zones, key: identifier);
1723 if (tz)
1724 {
1725 g_atomic_int_inc (&tz->ref_count);
1726 G_UNLOCK (time_zones);
1727 return tz;
1728 }
1729 else
1730 resolved_identifier = g_strdup (str: identifier);
1731 }
1732 else
1733 {
1734 G_LOCK (tz_default);
1735#ifdef G_OS_UNIX
1736 resolved_identifier = zone_identifier_unix ();
1737#elif defined (G_OS_WIN32)
1738 resolved_identifier = windows_default_tzname ();
1739#endif
1740 if (tz_default)
1741 {
1742 /* Flush default if changed. If the identifier couldn’t be resolved,
1743 * we’re going to fall back to UTC eventually, so don’t clear out the
1744 * cache if it’s already UTC. */
1745 if (!(resolved_identifier == NULL && g_str_equal (v1: tz_default->name, v2: "UTC")) &&
1746 g_strcmp0 (str1: tz_default->name, str2: resolved_identifier) != 0)
1747 {
1748 g_clear_pointer (&tz_default, g_time_zone_unref);
1749 }
1750 else
1751 {
1752 tz = g_time_zone_ref (tz: tz_default);
1753 G_UNLOCK (tz_default);
1754
1755 g_free (mem: resolved_identifier);
1756 return tz;
1757 }
1758 }
1759 }
1760
1761 tz = g_slice_new0 (GTimeZone);
1762 tz->ref_count = 0;
1763
1764 zone_for_constant_offset (gtz: tz, name: identifier);
1765
1766 if (tz->t_info == NULL &&
1767 (rules_num = rules_from_identifier (identifier, rules: &rules)))
1768 {
1769 init_zone_from_rules (gtz: tz, rules, rules_num, g_steal_pointer (&resolved_identifier));
1770 g_free (mem: rules);
1771 }
1772
1773 if (tz->t_info == NULL)
1774 {
1775#ifdef G_OS_UNIX
1776 GBytes *zoneinfo = zone_info_unix (identifier, resolved_identifier);
1777 if (zoneinfo != NULL)
1778 {
1779 init_zone_from_iana_info (gtz: tz, zoneinfo, g_steal_pointer (&resolved_identifier));
1780 g_bytes_unref (bytes: zoneinfo);
1781 }
1782#elif defined (G_OS_WIN32)
1783 if ((rules_num = rules_from_windows_time_zone (identifier,
1784 resolved_identifier,
1785 &rules)))
1786 {
1787 init_zone_from_rules (tz, rules, rules_num, g_steal_pointer (&resolved_identifier));
1788 g_free (rules);
1789 }
1790#endif
1791 }
1792
1793#if defined (G_OS_WIN32)
1794 if (tz->t_info == NULL)
1795 {
1796 if (identifier == NULL)
1797 {
1798 TIME_ZONE_INFORMATION tzi;
1799
1800 if (GetTimeZoneInformation (&tzi) != TIME_ZONE_ID_INVALID)
1801 {
1802 rules = g_new0 (TimeZoneRule, 2);
1803
1804 if (rule_from_windows_time_zone_info (&rules[0], &tzi))
1805 {
1806 memset (rules[0].std_name, 0, NAME_SIZE);
1807 memset (rules[0].dlt_name, 0, NAME_SIZE);
1808
1809 rules[0].start_year = MIN_TZYEAR;
1810 rules[1].start_year = MAX_TZYEAR;
1811
1812 init_zone_from_rules (tz, rules, 2, g_steal_pointer (&resolved_identifier));
1813 }
1814
1815 g_free (rules);
1816 }
1817 }
1818 }
1819#endif
1820
1821 g_free (mem: resolved_identifier);
1822
1823 /* Failed to load the timezone. */
1824 if (tz->t_info == NULL)
1825 {
1826 g_slice_free (GTimeZone, tz);
1827
1828 if (identifier)
1829 G_UNLOCK (time_zones);
1830 else
1831 G_UNLOCK (tz_default);
1832
1833 return NULL;
1834 }
1835
1836 g_assert (tz->name != NULL);
1837 g_assert (tz->t_info != NULL);
1838
1839 if (identifier)
1840 g_hash_table_insert (hash_table: time_zones, key: tz->name, value: tz);
1841 else if (tz->name)
1842 {
1843 /* Caching reference */
1844 g_atomic_int_inc (&tz->ref_count);
1845 tz_default = tz;
1846 }
1847
1848 g_atomic_int_inc (&tz->ref_count);
1849
1850 if (identifier)
1851 G_UNLOCK (time_zones);
1852 else
1853 G_UNLOCK (tz_default);
1854
1855 return tz;
1856}
1857
1858/**
1859 * g_time_zone_new_utc:
1860 *
1861 * Creates a #GTimeZone corresponding to UTC.
1862 *
1863 * This is equivalent to calling g_time_zone_new() with a value like
1864 * "Z", "UTC", "+00", etc.
1865 *
1866 * You should release the return value by calling g_time_zone_unref()
1867 * when you are done with it.
1868 *
1869 * Returns: the universal timezone
1870 *
1871 * Since: 2.26
1872 **/
1873GTimeZone *
1874g_time_zone_new_utc (void)
1875{
1876 static GTimeZone *utc = NULL;
1877 static gsize initialised;
1878
1879 if (g_once_init_enter (&initialised))
1880 {
1881 utc = g_time_zone_new_identifier (identifier: "UTC");
1882 g_assert (utc != NULL);
1883 g_once_init_leave (&initialised, TRUE);
1884 }
1885
1886 return g_time_zone_ref (tz: utc);
1887}
1888
1889/**
1890 * g_time_zone_new_local:
1891 *
1892 * Creates a #GTimeZone corresponding to local time. The local time
1893 * zone may change between invocations to this function; for example,
1894 * if the system administrator changes it.
1895 *
1896 * This is equivalent to calling g_time_zone_new() with the value of
1897 * the `TZ` environment variable (including the possibility of %NULL).
1898 *
1899 * You should release the return value by calling g_time_zone_unref()
1900 * when you are done with it.
1901 *
1902 * Returns: the local timezone
1903 *
1904 * Since: 2.26
1905 **/
1906GTimeZone *
1907g_time_zone_new_local (void)
1908{
1909 const gchar *tzenv = g_getenv (variable: "TZ");
1910 GTimeZone *tz;
1911
1912 G_LOCK (tz_local);
1913
1914 /* Is time zone changed and must be flushed? */
1915 if (tz_local && g_strcmp0 (str1: g_time_zone_get_identifier (tz: tz_local), str2: tzenv))
1916 g_clear_pointer (&tz_local, g_time_zone_unref);
1917
1918 if (tz_local == NULL)
1919 tz_local = g_time_zone_new_identifier (identifier: tzenv);
1920 if (tz_local == NULL)
1921 tz_local = g_time_zone_new_utc ();
1922
1923 tz = g_time_zone_ref (tz: tz_local);
1924
1925 G_UNLOCK (tz_local);
1926
1927 return tz;
1928}
1929
1930/**
1931 * g_time_zone_new_offset:
1932 * @seconds: offset to UTC, in seconds
1933 *
1934 * Creates a #GTimeZone corresponding to the given constant offset from UTC,
1935 * in seconds.
1936 *
1937 * This is equivalent to calling g_time_zone_new() with a string in the form
1938 * `[+|-]hh[:mm[:ss]]`.
1939 *
1940 * Returns: (transfer full): a timezone at the given offset from UTC
1941 * Since: 2.58
1942 */
1943GTimeZone *
1944g_time_zone_new_offset (gint32 seconds)
1945{
1946 GTimeZone *tz = NULL;
1947 gchar *identifier = NULL;
1948
1949 /* Seemingly, we should be using @seconds directly to set the
1950 * #TransitionInfo.gmt_offset to avoid all this string building and parsing.
1951 * However, we always need to set the #GTimeZone.name to a constructed
1952 * string anyway, so we might as well reuse its code.
1953 * g_time_zone_new_identifier() should never fail in this situation. */
1954 identifier = g_strdup_printf (format: "%c%02u:%02u:%02u",
1955 (seconds >= 0) ? '+' : '-',
1956 (ABS (seconds) / 60) / 60,
1957 (ABS (seconds) / 60) % 60,
1958 ABS (seconds) % 60);
1959 tz = g_time_zone_new_identifier (identifier);
1960 g_assert (tz != NULL);
1961 g_free (mem: identifier);
1962
1963 g_assert (g_time_zone_get_offset (tz, 0) == seconds);
1964
1965 return tz;
1966}
1967
1968#define TRANSITION(n) g_array_index (tz->transitions, Transition, n)
1969#define TRANSITION_INFO(n) g_array_index (tz->t_info, TransitionInfo, n)
1970
1971/* Internal helpers {{{1 */
1972/* NB: Interval 0 is before the first transition, so there's no
1973 * transition structure to point to which TransitionInfo to
1974 * use. Rule-based zones are set up so that TI 0 is always standard
1975 * time (which is what's in effect before Daylight time got started
1976 * in the early 20th century), but IANA tzfiles don't follow that
1977 * convention. The tzfile documentation says to use the first
1978 * standard-time (i.e., non-DST) tinfo, so that's what we do.
1979 */
1980inline static const TransitionInfo*
1981interval_info (GTimeZone *tz,
1982 guint interval)
1983{
1984 guint index;
1985 g_return_val_if_fail (tz->t_info != NULL, NULL);
1986 if (interval && tz->transitions && interval <= tz->transitions->len)
1987 index = (TRANSITION(interval - 1)).info_index;
1988 else
1989 {
1990 for (index = 0; index < tz->t_info->len; index++)
1991 {
1992 TransitionInfo *tzinfo = &(TRANSITION_INFO(index));
1993 if (!tzinfo->is_dst)
1994 return tzinfo;
1995 }
1996 index = 0;
1997 }
1998
1999 return &(TRANSITION_INFO(index));
2000}
2001
2002inline static gint64
2003interval_start (GTimeZone *tz,
2004 guint interval)
2005{
2006 if (!interval || tz->transitions == NULL || tz->transitions->len == 0)
2007 return G_MININT64;
2008 if (interval > tz->transitions->len)
2009 interval = tz->transitions->len;
2010 return (TRANSITION(interval - 1)).time;
2011}
2012
2013inline static gint64
2014interval_end (GTimeZone *tz,
2015 guint interval)
2016{
2017 if (tz->transitions && interval < tz->transitions->len)
2018 {
2019 gint64 lim = (TRANSITION(interval)).time;
2020 return lim - (lim != G_MININT64);
2021 }
2022 return G_MAXINT64;
2023}
2024
2025inline static gint32
2026interval_offset (GTimeZone *tz,
2027 guint interval)
2028{
2029 g_return_val_if_fail (tz->t_info != NULL, 0);
2030 return interval_info (tz, interval)->gmt_offset;
2031}
2032
2033inline static gboolean
2034interval_isdst (GTimeZone *tz,
2035 guint interval)
2036{
2037 g_return_val_if_fail (tz->t_info != NULL, 0);
2038 return interval_info (tz, interval)->is_dst;
2039}
2040
2041
2042inline static gchar*
2043interval_abbrev (GTimeZone *tz,
2044 guint interval)
2045{
2046 g_return_val_if_fail (tz->t_info != NULL, 0);
2047 return interval_info (tz, interval)->abbrev;
2048}
2049
2050inline static gint64
2051interval_local_start (GTimeZone *tz,
2052 guint interval)
2053{
2054 if (interval)
2055 return interval_start (tz, interval) + interval_offset (tz, interval);
2056
2057 return G_MININT64;
2058}
2059
2060inline static gint64
2061interval_local_end (GTimeZone *tz,
2062 guint interval)
2063{
2064 if (tz->transitions && interval < tz->transitions->len)
2065 return interval_end (tz, interval) + interval_offset (tz, interval);
2066
2067 return G_MAXINT64;
2068}
2069
2070static gboolean
2071interval_valid (GTimeZone *tz,
2072 guint interval)
2073{
2074 if ( tz->transitions == NULL)
2075 return interval == 0;
2076 return interval <= tz->transitions->len;
2077}
2078
2079/* g_time_zone_find_interval() {{{1 */
2080
2081/**
2082 * g_time_zone_adjust_time:
2083 * @tz: a #GTimeZone
2084 * @type: the #GTimeType of @time_
2085 * @time_: a pointer to a number of seconds since January 1, 1970
2086 *
2087 * Finds an interval within @tz that corresponds to the given @time_,
2088 * possibly adjusting @time_ if required to fit into an interval.
2089 * The meaning of @time_ depends on @type.
2090 *
2091 * This function is similar to g_time_zone_find_interval(), with the
2092 * difference that it always succeeds (by making the adjustments
2093 * described below).
2094 *
2095 * In any of the cases where g_time_zone_find_interval() succeeds then
2096 * this function returns the same value, without modifying @time_.
2097 *
2098 * This function may, however, modify @time_ in order to deal with
2099 * non-existent times. If the non-existent local @time_ of 02:30 were
2100 * requested on March 14th 2010 in Toronto then this function would
2101 * adjust @time_ to be 03:00 and return the interval containing the
2102 * adjusted time.
2103 *
2104 * Returns: the interval containing @time_, never -1
2105 *
2106 * Since: 2.26
2107 **/
2108gint
2109g_time_zone_adjust_time (GTimeZone *tz,
2110 GTimeType type,
2111 gint64 *time_)
2112{
2113 guint i, intervals;
2114 gboolean interval_is_dst;
2115
2116 if (tz->transitions == NULL)
2117 return 0;
2118
2119 intervals = tz->transitions->len;
2120
2121 /* find the interval containing *time UTC
2122 * TODO: this could be binary searched (or better) */
2123 for (i = 0; i <= intervals; i++)
2124 if (*time_ <= interval_end (tz, interval: i))
2125 break;
2126
2127 g_assert (interval_start (tz, i) <= *time_ && *time_ <= interval_end (tz, i));
2128
2129 if (type != G_TIME_TYPE_UNIVERSAL)
2130 {
2131 if (*time_ < interval_local_start (tz, interval: i))
2132 /* if time came before the start of this interval... */
2133 {
2134 i--;
2135
2136 /* if it's not in the previous interval... */
2137 if (*time_ > interval_local_end (tz, interval: i))
2138 {
2139 /* it doesn't exist. fast-forward it. */
2140 i++;
2141 *time_ = interval_local_start (tz, interval: i);
2142 }
2143 }
2144
2145 else if (*time_ > interval_local_end (tz, interval: i))
2146 /* if time came after the end of this interval... */
2147 {
2148 i++;
2149
2150 /* if it's not in the next interval... */
2151 if (*time_ < interval_local_start (tz, interval: i))
2152 /* it doesn't exist. fast-forward it. */
2153 *time_ = interval_local_start (tz, interval: i);
2154 }
2155
2156 else
2157 {
2158 interval_is_dst = interval_isdst (tz, interval: i);
2159 if ((interval_is_dst && type != G_TIME_TYPE_DAYLIGHT) ||
2160 (!interval_is_dst && type == G_TIME_TYPE_DAYLIGHT))
2161 {
2162 /* it's in this interval, but dst flag doesn't match.
2163 * check neighbours for a better fit. */
2164 if (i && *time_ <= interval_local_end (tz, interval: i - 1))
2165 i--;
2166
2167 else if (i < intervals &&
2168 *time_ >= interval_local_start (tz, interval: i + 1))
2169 i++;
2170 }
2171 }
2172 }
2173
2174 return i;
2175}
2176
2177/**
2178 * g_time_zone_find_interval:
2179 * @tz: a #GTimeZone
2180 * @type: the #GTimeType of @time_
2181 * @time_: a number of seconds since January 1, 1970
2182 *
2183 * Finds an interval within @tz that corresponds to the given @time_.
2184 * The meaning of @time_ depends on @type.
2185 *
2186 * If @type is %G_TIME_TYPE_UNIVERSAL then this function will always
2187 * succeed (since universal time is monotonic and continuous).
2188 *
2189 * Otherwise @time_ is treated as local time. The distinction between
2190 * %G_TIME_TYPE_STANDARD and %G_TIME_TYPE_DAYLIGHT is ignored except in
2191 * the case that the given @time_ is ambiguous. In Toronto, for example,
2192 * 01:30 on November 7th 2010 occurred twice (once inside of daylight
2193 * savings time and the next, an hour later, outside of daylight savings
2194 * time). In this case, the different value of @type would result in a
2195 * different interval being returned.
2196 *
2197 * It is still possible for this function to fail. In Toronto, for
2198 * example, 02:00 on March 14th 2010 does not exist (due to the leap
2199 * forward to begin daylight savings time). -1 is returned in that
2200 * case.
2201 *
2202 * Returns: the interval containing @time_, or -1 in case of failure
2203 *
2204 * Since: 2.26
2205 */
2206gint
2207g_time_zone_find_interval (GTimeZone *tz,
2208 GTimeType type,
2209 gint64 time_)
2210{
2211 guint i, intervals;
2212 gboolean interval_is_dst;
2213
2214 if (tz->transitions == NULL)
2215 return 0;
2216 intervals = tz->transitions->len;
2217 for (i = 0; i <= intervals; i++)
2218 if (time_ <= interval_end (tz, interval: i))
2219 break;
2220
2221 if (type == G_TIME_TYPE_UNIVERSAL)
2222 return i;
2223
2224 if (time_ < interval_local_start (tz, interval: i))
2225 {
2226 if (time_ > interval_local_end (tz, interval: --i))
2227 return -1;
2228 }
2229
2230 else if (time_ > interval_local_end (tz, interval: i))
2231 {
2232 if (time_ < interval_local_start (tz, interval: ++i))
2233 return -1;
2234 }
2235
2236 else
2237 {
2238 interval_is_dst = interval_isdst (tz, interval: i);
2239 if ((interval_is_dst && type != G_TIME_TYPE_DAYLIGHT) ||
2240 (!interval_is_dst && type == G_TIME_TYPE_DAYLIGHT))
2241 {
2242 if (i && time_ <= interval_local_end (tz, interval: i - 1))
2243 i--;
2244
2245 else if (i < intervals && time_ >= interval_local_start (tz, interval: i + 1))
2246 i++;
2247 }
2248 }
2249
2250 return i;
2251}
2252
2253/* Public API accessors {{{1 */
2254
2255/**
2256 * g_time_zone_get_abbreviation:
2257 * @tz: a #GTimeZone
2258 * @interval: an interval within the timezone
2259 *
2260 * Determines the time zone abbreviation to be used during a particular
2261 * @interval of time in the time zone @tz.
2262 *
2263 * For example, in Toronto this is currently "EST" during the winter
2264 * months and "EDT" during the summer months when daylight savings time
2265 * is in effect.
2266 *
2267 * Returns: the time zone abbreviation, which belongs to @tz
2268 *
2269 * Since: 2.26
2270 **/
2271const gchar *
2272g_time_zone_get_abbreviation (GTimeZone *tz,
2273 gint interval)
2274{
2275 g_return_val_if_fail (interval_valid (tz, (guint)interval), NULL);
2276
2277 return interval_abbrev (tz, interval: (guint)interval);
2278}
2279
2280/**
2281 * g_time_zone_get_offset:
2282 * @tz: a #GTimeZone
2283 * @interval: an interval within the timezone
2284 *
2285 * Determines the offset to UTC in effect during a particular @interval
2286 * of time in the time zone @tz.
2287 *
2288 * The offset is the number of seconds that you add to UTC time to
2289 * arrive at local time for @tz (ie: negative numbers for time zones
2290 * west of GMT, positive numbers for east).
2291 *
2292 * Returns: the number of seconds that should be added to UTC to get the
2293 * local time in @tz
2294 *
2295 * Since: 2.26
2296 **/
2297gint32
2298g_time_zone_get_offset (GTimeZone *tz,
2299 gint interval)
2300{
2301 g_return_val_if_fail (interval_valid (tz, (guint)interval), 0);
2302
2303 return interval_offset (tz, interval: (guint)interval);
2304}
2305
2306/**
2307 * g_time_zone_is_dst:
2308 * @tz: a #GTimeZone
2309 * @interval: an interval within the timezone
2310 *
2311 * Determines if daylight savings time is in effect during a particular
2312 * @interval of time in the time zone @tz.
2313 *
2314 * Returns: %TRUE if daylight savings time is in effect
2315 *
2316 * Since: 2.26
2317 **/
2318gboolean
2319g_time_zone_is_dst (GTimeZone *tz,
2320 gint interval)
2321{
2322 g_return_val_if_fail (interval_valid (tz, interval), FALSE);
2323
2324 if (tz->transitions == NULL)
2325 return FALSE;
2326
2327 return interval_isdst (tz, interval: (guint)interval);
2328}
2329
2330/**
2331 * g_time_zone_get_identifier:
2332 * @tz: a #GTimeZone
2333 *
2334 * Get the identifier of this #GTimeZone, as passed to g_time_zone_new().
2335 * If the identifier passed at construction time was not recognised, `UTC` will
2336 * be returned. If it was %NULL, the identifier of the local timezone at
2337 * construction time will be returned.
2338 *
2339 * The identifier will be returned in the same format as provided at
2340 * construction time: if provided as a time offset, that will be returned by
2341 * this function.
2342 *
2343 * Returns: identifier for this timezone
2344 * Since: 2.58
2345 */
2346const gchar *
2347g_time_zone_get_identifier (GTimeZone *tz)
2348{
2349 g_return_val_if_fail (tz != NULL, NULL);
2350
2351 return tz->name;
2352}
2353
2354/* Epilogue {{{1 */
2355/* vim:set foldmethod=marker: */
2356

source code of gtk/subprojects/glib/glib/gtimezone.c