/* -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 4 -*- */
/*======================================================================
FILE: icaltimezone.h
CREATOR: Damon Chaplin 15 March 2001
$Id$
$Locker$
(C) COPYRIGHT 2001, Damon Chaplin
This program is free software; you can redistribute it and/or modify
it under the terms of either:
The LGPL as published by the Free Software Foundation, version
2.1, available at: http://www.fsf.org/copyleft/lesser.html
Or:
The Mozilla Public License Version 1.0. You may obtain a copy of
the License at http://www.mozilla.org/MPL/
======================================================================*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "icalproperty.h"
#include "icalarray.h"
#include "icalerror.h"
#include "icalparser.h"
#include "icaltimezone.h"
/* This is the toplevel directory where the timezone data is installed in. */
#define ZONEINFO_DIRECTORY PACKAGE_DATA_DIR "/zoneinfo"
/* The prefix we use to uniquely identify TZIDs. */
#define TZID_PREFIX "/softwarestudio.org/"
#define TZID_PREFIX_LEN 20
/* This is the filename of the file containing the city names and coordinates
of all the builtin timezones. */
#define ZONES_TAB_FILENAME "zones.tab"
/* This is the number of years of extra coverage we do when expanding the
timezone changes. */
#define ICALTIMEZONE_EXTRA_COVERAGE 5
/* This is the maximum year we will expand to. time_t values only go up to
somewhere around 2037. */
#define ICALTIMEZONE_MAX_YEAR 2035
struct _icaltimezone {
/* The unique ID of this timezone,
e.g. "/softwarestudio.org/Olson_20010601_1/Africa/Banjul".
This should only be used to identify a VTIMEZONE. It is not meant to
be displayed to the user in any form. */
char *tzid;
/* The location for the timezone, e.g. "Africa/Accra" for the Olson
database. We look for this in the "LOCATION" or "X-LIC-LOCATION"
properties of the VTIMEZONE component. It isn't a standard property
yet. This will be NULL if no location is found in the VTIMEZONE. */
char *location;
/* This will be set to a combination of the TZNAME properties from the last
STANDARD and DAYLIGHT components in the VTIMEZONE, e.g. "EST/EDT".
If they both use the same TZNAME, or only one type of component is
found, then only one TZNAME will appear, e.g. "AZOT". If no TZNAME
is found this will be NULL. */
char *tznames;
/* The coordinates of the city, in degrees. */
double latitude;
double longitude;
/* The toplevel VTIMEZONE component loaded from the .ics file for this
timezone. If we need to regenerate the changes data we need this. */
icalcomponent *component;
/* If this is not NULL it points to the builtin icaltimezone that the
above TZID refers to. This icaltimezone should be used instead when
accessing the timezone changes data, so that the expanded timezone
changes data is shared between calendar components. */
icaltimezone *builtin_timezone;
/* This is the last year for which we have expanded the data to.
If we need to calculate a date past this we need to expand the
timezone component data from scratch. */
int end_year;
/* A dynamically-allocated array of time zone changes, sorted by the
time of the change in local time. So we can do fast binary-searches
to convert from local time to UTC. */
icalarray *changes;
};
typedef struct _icaltimezonechange icaltimezonechange;
struct _icaltimezonechange {
/* The offset to add to UTC to get local time, in seconds. */
int utc_offset;
/* The offset to add to UTC, before this change, in seconds. */
int prev_utc_offset;
/* The time that the change came into effect, in UTC.
Note that the prev_utc_offset applies to this local time,
since we haven't changed to the new offset yet. */
int year; /* Actual year, e.g. 2001. */
char month; /* 1 (Jan) to 12 (Dec). */
char day;
char hour;
char minute;
char second;
/* Whether this is STANDARD or DAYLIGHT time. */
char is_daylight;
};
/* An array of icaltimezones for the builtin timezones. */
icalarray *builtin_timezones = NULL;
/* This is the special UTC timezone, which isn't in builtin_timezones. */
icaltimezone utc_timezone = { 0 };
static void icaltimezone_reset (icaltimezone *zone);
static char* icaltimezone_get_location_from_vtimezone (icalcomponent *component);
static char* icaltimezone_get_tznames_from_vtimezone (icalcomponent *component);
static void icaltimezone_expand_changes (icaltimezone *zone,
int end_year);
static void icaltimezone_expand_vtimezone (icalcomponent *comp,
int end_year,
icalarray *changes);
static int icaltimezone_compare_change_fn (const void *elem1,
const void *elem2);
static int icaltimezone_find_nearby_change (icaltimezone *zone,
icaltimezonechange *change);
static void icaltimezone_adjust_change (icaltimezonechange *tt,
int days,
int hours,
int minutes,
int seconds);
static void icaltimezone_init (icaltimezone *zone);
/* Gets the TZID, LOCATION/X-LIC-LOCATION, and TZNAME properties from the
VTIMEZONE component and places them in the icaltimezone. It returns 1 on
success, or 0 if the TZID can't be found. */
static int icaltimezone_get_vtimezone_properties (icaltimezone *zone,
icalcomponent *component);
static void icaltimezone_load_builtin_timezone (icaltimezone *zone);
static void icaltimezone_ensure_coverage (icaltimezone *zone,
int end_year);
static void icaltimezone_init_builtin_timezones(void);
static void icaltimezone_parse_zone_tab (void);
static char* icaltimezone_load_get_line_fn (char *s,
size_t size,
void *data);
static void format_utc_offset (int utc_offset,
char *buffer);
/* Creates a new icaltimezone. */
icaltimezone*
icaltimezone_new (void)
{
icaltimezone *zone;
zone = (icaltimezone*) malloc (sizeof (icaltimezone));
if (!zone) {
icalerror_set_errno (ICAL_NEWFAILED_ERROR);
return;
}
icaltimezone_init (zone);
return zone;
}
/* Frees all memory used for the icaltimezone. */
void
icaltimezone_free (icaltimezone *zone,
int free_struct)
{
icaltimezone_reset (zone);
if (free_struct)
free (zone);
}
/* Resets the icaltimezone to the initial state, freeing most of the fields. */
static void
icaltimezone_reset (icaltimezone *zone)
{
if (zone->tzid)
free (zone->tzid);
if (zone->location)
free (zone->location);
if (zone->tznames)
free (zone->tznames);
if (zone->component)
icalcomponent_free (zone->component);
if (zone->changes)
icalarray_free (zone->changes);
icaltimezone_init (zone);
}
/* Initializes an icaltimezone. */
static void
icaltimezone_init (icaltimezone *zone)
{
zone->tzid = NULL;
zone->location = NULL;
zone->tznames = NULL;
zone->latitude = 0.0;
zone->longitude = 0.0;
zone->component = NULL;
zone->builtin_timezone = NULL;
zone->end_year = 0;
zone->changes = NULL;
}
/* Gets the TZID, LOCATION/X-LIC-LOCATION and TZNAME properties of the
VTIMEZONE component and stores them in the icaltimezone.
It returns 1 on success, or 0 if the TZID can't be found.
Note that it expects the zone to be initialized or reset - it doesn't free
any old values. */
static int
icaltimezone_get_vtimezone_properties (icaltimezone *zone,
icalcomponent *component)
{
icalproperty *prop;
const char *tzid, *location;
prop = icalcomponent_get_first_property (component, ICAL_TZID_PROPERTY);
if (!prop)
return 0;
/* A VTIMEZONE MUST have a TZID, or a lot of our code won't work. */
tzid = icalproperty_get_tzid (prop);
if (!tzid)
return 0;
zone->tzid = strdup (tzid);
zone->component = component;
zone->location = icaltimezone_get_location_from_vtimezone (component);
zone->tznames = icaltimezone_get_tznames_from_vtimezone (component);
return 1;
}
/* Gets the LOCATION or X-LIC-LOCATION property from a VTIMEZONE. */
static char*
icaltimezone_get_location_from_vtimezone (icalcomponent *component)
{
icalproperty *prop;
const char *location;
char *name;
int found_location = 0;
prop = icalcomponent_get_first_property (component,
ICAL_LOCATION_PROPERTY);
if (prop) {
location = icalproperty_get_location (prop);
if (location)
return strdup (location);
}
prop = icalcomponent_get_first_property (component, ICAL_X_PROPERTY);
while (prop) {
name = icalproperty_get_x_name (prop);
if (name && !strcmp (name, "X-LIC-LOCATION")) {
location = icalproperty_get_x (prop);
if (location)
return strdup (location);
}
prop = icalcomponent_get_next_property (component,
ICAL_X_PROPERTY);
}
return NULL;
}
/* Gets the TZNAMEs used for the last STANDARD & DAYLIGHT components in a
VTIMEZONE. If both STANDARD and DAYLIGHT components use the same TZNAME,
it returns that. If they use different TZNAMEs, it formats them like
"EST/EDT". The returned string should be freed by the caller. */
static char*
icaltimezone_get_tznames_from_vtimezone (icalcomponent *component)
{
icalcomponent *comp;
icalcomponent_kind type;
icalproperty *prop;
struct icaltimetype dtstart;
struct icaldatetimeperiodtype rdate;
const char *current_tzname;
const char *standard_tzname = NULL, *daylight_tzname = NULL;
struct icaltimetype standard_max_date, daylight_max_date;
struct icaltimetype current_max_date;
/* Step through the STANDARD & DAYLIGHT subcomponents. */
comp = icalcomponent_get_first_component (component, ICAL_ANY_COMPONENT);
while (comp) {
type = icalcomponent_isa (comp);
if (type == ICAL_XSTANDARD_COMPONENT
|| type == ICAL_XDAYLIGHT_COMPONENT) {
current_max_date = icaltime_null_time ();
current_tzname = NULL;
/* Step through the properties. We want to find the TZNAME, and
the largest DTSTART or RDATE. */
prop = icalcomponent_get_first_property (comp, ICAL_ANY_PROPERTY);
while (prop) {
switch (icalproperty_isa (prop)) {
case ICAL_TZNAME_PROPERTY:
current_tzname = icalproperty_get_tzname (prop);
break;
case ICAL_DTSTART_PROPERTY:
dtstart = icalproperty_get_dtstart (prop);
if (icaltime_compare (dtstart, current_max_date) > 0)
current_max_date = dtstart;
break;
case ICAL_RDATE_PROPERTY:
rdate = icalproperty_get_rdate (prop);
if (icaltime_compare (rdate.time, current_max_date) > 0)
current_max_date = rdate.time;
break;
default:
break;
}
prop = icalcomponent_get_next_property (comp,
ICAL_ANY_PROPERTY);
}
if (current_tzname) {
if (type == ICAL_XSTANDARD_COMPONENT) {
if (!standard_tzname
|| icaltime_compare (current_max_date,
standard_max_date) > 0) {
standard_max_date = current_max_date;
standard_tzname = current_tzname;
}
} else {
if (!daylight_tzname
|| icaltime_compare (current_max_date,
daylight_max_date) > 0) {
daylight_max_date = current_max_date;
daylight_tzname = current_tzname;
}
}
}
}
comp = icalcomponent_get_next_component (component,
ICAL_ANY_COMPONENT);
}
/* If both standard and daylight TZNAMEs were found, if they are the same
we return just one, else we format them like "EST/EDT". */
if (standard_tzname && daylight_tzname) {
int standard_len, daylight_len;
char *tznames;
if (!strcmp (standard_tzname, daylight_tzname))
return strdup (standard_tzname);
standard_len = strlen (standard_tzname);
daylight_len = strlen (daylight_tzname);
tznames = malloc (standard_len + daylight_len + 2);
strcpy (tznames, standard_tzname);
tznames[standard_len] = '/';
strcpy (tznames + standard_len + 1, daylight_tzname);
return tznames;
} else {
const char *tznames;
/* If either of the TZNAMEs was found just return that, else NULL. */
tznames = standard_tzname ? standard_tzname : daylight_tzname;
return tznames ? strdup (tznames) : NULL;
}
}
static void
icaltimezone_ensure_coverage (icaltimezone *zone,
int end_year)
{
/* When we expand timezone changes we always expand at least up to this
year, plus ICALTIMEZONE_EXTRA_COVERAGE. */
static int icaltimezone_minimum_expansion_year = -1;
int changes_end_year;
if (!zone->component)
icaltimezone_load_builtin_timezone (zone);
if (icaltimezone_minimum_expansion_year == -1) {
struct tm *tmp_tm;
time_t t;
t = time (NULL);
tmp_tm = localtime (&t);
icaltimezone_minimum_expansion_year = tmp_tm->tm_year + 1900;
}
changes_end_year = end_year;
if (changes_end_year < icaltimezone_minimum_expansion_year)
changes_end_year = icaltimezone_minimum_expansion_year;
changes_end_year += ICALTIMEZONE_EXTRA_COVERAGE;
if (changes_end_year > ICALTIMEZONE_MAX_YEAR)
changes_end_year = ICALTIMEZONE_MAX_YEAR;
if (!zone->changes || zone->end_year < end_year)
icaltimezone_expand_changes (zone, changes_end_year);
}
static void
icaltimezone_expand_changes (icaltimezone *zone,
int end_year)
{
icalarray *changes;
icalcomponent *comp;
#if 0
printf ("\nExpanding changes for: %s to year: %i\n", zone->tzid, end_year);
#endif
changes = icalarray_new (sizeof (icaltimezonechange), 32);
if (!changes)
return;
/* Scan the STANDARD and DAYLIGHT subcomponents. */
comp = icalcomponent_get_first_component (zone->component,
ICAL_ANY_COMPONENT);
while (comp) {
icaltimezone_expand_vtimezone (comp, end_year, changes);
comp = icalcomponent_get_next_component (zone->component,
ICAL_ANY_COMPONENT);
}
/* Sort the changes. We may have duplicates but I don't think it will
matter. */
icalarray_sort (changes, icaltimezone_compare_change_fn);
if (zone->changes)
icalarray_free (zone->changes);
zone->changes = changes;
zone->end_year = end_year;
}
static void
icaltimezone_expand_vtimezone (icalcomponent *comp,
int end_year,
icalarray *changes)
{
icaltimezonechange change;
icalproperty *prop;
struct icaltimetype dtstart, occ;
struct icalrecurrencetype rrule;
icalrecur_iterator* rrule_iterator;
struct icaldatetimeperiodtype rdate;
int found_dtstart = 0, found_tzoffsetto = 0, found_tzoffsetfrom = 0;
int has_recurrence = 0;
/* First we check if it is a STANDARD or DAYLIGHT component, and
just return if it isn't. */
if (icalcomponent_isa (comp) == ICAL_XSTANDARD_COMPONENT)
change.is_daylight = 0;
else if (icalcomponent_isa (comp) == ICAL_XDAYLIGHT_COMPONENT)
change.is_daylight = 1;
else
return;
/* Step through each of the properties to find the DTSTART,
TZOFFSETFROM and TZOFFSETTO. We can't expand recurrences here
since we need these properties before we can do that. */
prop = icalcomponent_get_first_property (comp, ICAL_ANY_PROPERTY);
while (prop) {
switch (icalproperty_isa (prop)) {
case ICAL_DTSTART_PROPERTY:
dtstart = icalproperty_get_dtstart (prop);
found_dtstart = 1;
break;
case ICAL_TZOFFSETTO_PROPERTY:
change.utc_offset = icalproperty_get_tzoffsetto (prop);
/*printf ("Found TZOFFSETTO: %i\n", change.utc_offset);*/
found_tzoffsetto = 1;
break;
case ICAL_TZOFFSETFROM_PROPERTY:
change.prev_utc_offset = icalproperty_get_tzoffsetfrom (prop);
/*printf ("Found TZOFFSETFROM: %i\n", change.prev_utc_offset);*/
found_tzoffsetfrom = 1;
break;
case ICAL_RDATE_PROPERTY:
case ICAL_RRULE_PROPERTY:
has_recurrence = 1;
break;
default:
/* Just ignore any other properties. */
break;
}
prop = icalcomponent_get_next_property (comp, ICAL_ANY_PROPERTY);
}
/* If we didn't find a DTSTART, TZOFFSETTO and TZOFFSETFROM we have to
ignore the component. FIXME: Add an error property? */
if (!found_dtstart || !found_tzoffsetto || !found_tzoffsetfrom)
return;
#if 0
printf ("\n Expanding component DTSTART (Y/M/D): %i/%i/%i %i:%02i:%02i\n",
dtstart.year, dtstart.month, dtstart.day,
dtstart.hour, dtstart.minute, dtstart.second);
#endif
/* If the STANDARD/DAYLIGHT component has no recurrence data, we just add
a single change for the DTSTART. */
if (!has_recurrence) {
change.year = dtstart.year;
change.month = dtstart.month;
change.day = dtstart.day;
change.hour = dtstart.hour;
change.minute = dtstart.minute;
change.second = dtstart.second;
/* Convert to UTC. */
icaltimezone_adjust_change (&change, 0, 0, 0, -change.prev_utc_offset);
#if 0
printf (" Appending single DTSTART (Y/M/D): %i/%02i/%02i %i:%02i:%02i\n",
change.year, change.month, change.day,
change.hour, change.minute, change.second);
#endif
/* Add the change to the array. */
icalarray_append (changes, &change);
return;
}
/* The component has recurrence data, so we expand that now. */
prop = icalcomponent_get_first_property (comp, ICAL_ANY_PROPERTY);
while (prop) {
#if 0
printf ("Expanding property...\n");
#endif
switch (icalproperty_isa (prop)) {
case ICAL_RDATE_PROPERTY:
rdate = icalproperty_get_rdate (prop);
change.year = rdate.time.year;
change.month = rdate.time.month;
change.day = rdate.time.day;
/* RDATEs with a DATE value inherit the time from
the DTSTART. */
if (rdate.time.is_date) {
change.hour = dtstart.hour;
change.minute = dtstart.minute;
change.second = dtstart.second;
} else {
change.hour = rdate.time.hour;
change.minute = rdate.time.minute;
change.second = rdate.time.second;
/* The spec was a bit vague about whether RDATEs were in local
time or UTC so we support both to be safe. So if it is in
UTC we have to add the UTC offset to get a local time. */
if (!rdate.time.is_utc)
icaltimezone_adjust_change (&change, 0, 0, 0,
-change.prev_utc_offset);
}
#if 0
printf (" Appending RDATE element (Y/M/D): %i/%02i/%02i %i:%02i:%02i\n",
change.year, change.month, change.day,
change.hour, change.minute, change.second);
#endif
icalarray_append (changes, &change);
break;
case ICAL_RRULE_PROPERTY:
rrule = icalproperty_get_rrule (prop);
/* If the rrule UNTIL value is set and is in UTC, we convert it to
a local time, since the recurrence code has no way to convert
it itself. */
if (!icaltime_is_null_time (rrule.until) && rrule.until.is_utc) {
#if 0
printf (" Found RRULE UNTIL in UTC.\n");
#endif
/* To convert from UTC to a local time, we use the TZOFFSETFROM
since that is the offset from UTC that will be in effect
when each of the RRULE occurrences happens. */
icaltime_adjust (&rrule.until, 0, 0, 0,
change.prev_utc_offset);
rrule.until.is_utc = 0;
}
rrule_iterator = icalrecur_iterator_new (rrule, dtstart);
for (;;) {
occ = icalrecur_iterator_next (rrule_iterator);
if (occ.year > end_year || icaltime_is_null_time (occ))
break;
change.year = occ.year;
change.month = occ.month;
change.day = occ.day;
change.hour = occ.hour;
change.minute = occ.minute;
change.second = occ.second;
#if 0
printf (" Appending RRULE element (Y/M/D): %i/%02i/%02i %i:%02i:%02i\n",
change.year, change.month, change.day,
change.hour, change.minute, change.second);
#endif
icaltimezone_adjust_change (&change, 0, 0, 0,
-change.prev_utc_offset);
icalarray_append (changes, &change);
}
icalrecur_iterator_free (rrule_iterator);
break;
default:
break;
}
prop = icalcomponent_get_next_property (comp, ICAL_ANY_PROPERTY);
}
}
/* A function to compare 2 icaltimezonechange elements, used for qsort(). */
static int
icaltimezone_compare_change_fn (const void *elem1,
const void *elem2)
{
const icaltimezonechange *change1, *change2;
int retval;
change1 = elem1;
change2 = elem2;
if (change1->year < change2->year)
retval = -1;
else if (change1->year > change2->year)
retval = 1;
else if (change1->month < change2->month)
retval = -1;
else if (change1->month > change2->month)
retval = 1;
else if (change1->day < change2->day)
retval = -1;
else if (change1->day > change2->day)
retval = 1;
else if (change1->hour < change2->hour)
retval = -1;
else if (change1->hour > change2->hour)
retval = 1;
else if (change1->minute < change2->minute)
retval = -1;
else if (change1->minute > change2->minute)
retval = 1;
else if (change1->second < change2->second)
retval = -1;
else if (change1->second > change2->second)
retval = 1;
else
retval = 0;
return retval;
}
void
icaltimezone_convert_time (struct icaltimetype *tt,
icaltimezone *from_zone,
icaltimezone *to_zone)
{
int utc_offset, is_daylight;
/* If the time is a DATE value or both timezones are the same, or we are
converting a floating time, we don't need to do anything. */
if (tt->is_date || from_zone == to_zone || from_zone == NULL)
return;
/* Convert the time to UTC by getting the UTC offset and subtracting it. */
utc_offset = icaltimezone_get_utc_offset (from_zone, tt, NULL);
icaltime_adjust (tt, 0, 0, 0, -utc_offset);
/* Now we convert the time to the new timezone by getting the UTC offset
of our UTC time and adding it. */
utc_offset = icaltimezone_get_utc_offset_of_utc_time (to_zone, tt,
&is_daylight);
tt->is_daylight = is_daylight;
icaltime_adjust (tt, 0, 0, 0, utc_offset);
}
/* Calculates the UTC offset of a given local time in the given timezone.
It is the number of seconds to add to UTC to get local time.
The is_daylight flag is set to 1 if the time is in daylight-savings time. */
int
icaltimezone_get_utc_offset (icaltimezone *zone,
struct icaltimetype *tt,
int *is_daylight)
{
icaltimezonechange *zone_change, *prev_zone_change, tt_change, tmp_change;
int change_num, step, utc_offset_change, cmp;
int change_num_to_use;
char want_daylight;
if (is_daylight)
*is_daylight = 0;
/* For local times and UTC return 0. */
if (zone == NULL || zone == &utc_timezone)
return 0;
/* Use the builtin icaltimezone if possible. */
if (zone->builtin_timezone)
zone = zone->builtin_timezone;
/* Make sure the changes array is expanded up to the given time. */
icaltimezone_ensure_coverage (zone, tt->year);
if (!zone->changes || zone->changes->num_elements == 0)
return 0;
/* Copy the time parts of the icaltimetype to an icaltimezonechange so we
can use our comparison function on it. */
tt_change.year = tt->year;
tt_change.month = tt->month;
tt_change.day = tt->day;
tt_change.hour = tt->hour;
tt_change.minute = tt->minute;
tt_change.second = tt->second;
/* This should find a change close to the time, either the change before
it or the change after it. */
change_num = icaltimezone_find_nearby_change (zone, &tt_change);
/* Sanity check. */
icalerror_assert (change_num >= 0,
"Negative timezone change index");
icalerror_assert (change_num < zone->changes->num_elements,
"Timezone change index out of bounds");
/* Now move backwards or forwards to find the timezone change that applies
to tt. It should only have to do 1 or 2 steps. */
zone_change = icalarray_element_at (zone->changes, change_num);
step = 1;
change_num_to_use = -1;
for (;;) {
/* Copy the change, so we can adjust it. */
tmp_change = *zone_change;
/* If the clock is going backward, check if it is in the region of time
that is used twice. If it is, use the change with the daylight
setting which matches tt, or use standard if we don't know. */
if (tmp_change.utc_offset < tmp_change.prev_utc_offset) {
/* If the time change is at 2:00AM local time and the clock is
going back to 1:00AM we adjust the change to 1:00AM. We may
have the wrong change but we'll figure that out later. */
icaltimezone_adjust_change (&tmp_change, 0, 0, 0,
tmp_change.utc_offset);
} else {
icaltimezone_adjust_change (&tmp_change, 0, 0, 0,
tmp_change.prev_utc_offset);
}
cmp = icaltimezone_compare_change_fn (&tt_change, &tmp_change);
/* If the given time is on or after this change, then this change may
apply, but we continue as a later change may be the right one.
If the given time is before this change, then if we have already
found a change which applies we can use that, else we need to step
backwards. */
if (cmp >= 0)
change_num_to_use = change_num;
else
step = -1;
/* If we are stepping backwards through the changes and we have found
a change that applies, then we know this is the change to use so
we exit the loop. */
if (step == -1 && change_num_to_use != -1)
break;
change_num += step;
/* If we go past the start of the changes array, then we have no data
for this time so we return a UTC offset of 0. */
if (change_num < 0)
return 0;
if (change_num >= zone->changes->num_elements)
break;
zone_change = icalarray_element_at (zone->changes, change_num);
}
/* If we didn't find a change to use, then we have a bug! */
icalerror_assert (change_num_to_use != -1,
"No applicable timezone change found");
/* Now we just need to check if the time is in the overlapped region of
time when clocks go back. */
zone_change = icalarray_element_at (zone->changes, change_num_to_use);
utc_offset_change = zone_change->utc_offset - zone_change->prev_utc_offset;
if (utc_offset_change < 0 && change_num_to_use > 0) {
tmp_change = *zone_change;
icaltimezone_adjust_change (&tmp_change, 0, 0, 0,
tmp_change.prev_utc_offset);
if (icaltimezone_compare_change_fn (&tt_change, &tmp_change) < 0) {
/* The time is in the overlapped region, so we may need to use
either the current zone_change or the previous one. If the
time has the is_daylight field set we use the matching change,
else we use the change with standard time. */
prev_zone_change = icalarray_element_at (zone->changes,
change_num_to_use - 1);
/* I was going to add an is_daylight flag to struct icaltimetype,
but iCalendar doesn't let us distinguish between standard and
daylight time anyway, so there's no point. So we just use the
standard time instead. */
want_daylight = (tt->is_daylight == 1) ? 1 : 0;
#if 0
if (zone_change->is_daylight == prev_zone_change->is_daylight)
printf (" **** Same is_daylight setting\n");
#endif
if (zone_change->is_daylight != want_daylight
&& prev_zone_change->is_daylight == want_daylight)
zone_change = prev_zone_change;
}
}
/* Now we know exactly which timezone change applies to the time, so
we can return the UTC offset and whether it is a daylight time. */
if (is_daylight)
*is_daylight = zone_change->is_daylight;
return zone_change->utc_offset;
}
/* Calculates the UTC offset of a given UTC time in the given timezone.
It is the number of seconds to add to UTC to get local time.
The is_daylight flag is set to 1 if the time is in daylight-savings time. */
int
icaltimezone_get_utc_offset_of_utc_time (icaltimezone *zone,
struct icaltimetype *tt,
int *is_daylight)
{
icaltimezonechange *zone_change, tt_change, tmp_change;
int change_num, step, change_num_to_use;
if (is_daylight)
*is_daylight = 0;
/* For local times and UTC return 0. */
if (zone == NULL || zone == &utc_timezone)
return 0;
/* Use the builtin icaltimezone if possible. */
if (zone->builtin_timezone)
zone = zone->builtin_timezone;
/* Make sure the changes array is expanded up to the given time. */
icaltimezone_ensure_coverage (zone, tt->year);
if (!zone->changes || zone->changes->num_elements == 0)
return 0;
/* Copy the time parts of the icaltimetype to an icaltimezonechange so we
can use our comparison function on it. */
tt_change.year = tt->year;
tt_change.month = tt->month;
tt_change.day = tt->day;
tt_change.hour = tt->hour;
tt_change.minute = tt->minute;
tt_change.second = tt->second;
/* This should find a change close to the time, either the change before
it or the change after it. */
change_num = icaltimezone_find_nearby_change (zone, &tt_change);
/* Sanity check. */
icalerror_assert (change_num >= 0,
"Negative timezone change index");
icalerror_assert (change_num < zone->changes->num_elements,
"Timezone change index out of bounds");
/* Now move backwards or forwards to find the timezone change that applies
to tt. It should only have to do 1 or 2 steps. */
zone_change = icalarray_element_at (zone->changes, change_num);
step = 1;
change_num_to_use = -1;
for (;;) {
/* Copy the change and adjust it to UTC. */
tmp_change = *zone_change;
/* If the given time is on or after this change, then this change may
apply, but we continue as a later change may be the right one.
If the given time is before this change, then if we have already
found a change which applies we can use that, else we need to step
backwards. */
if (icaltimezone_compare_change_fn (&tt_change, &tmp_change) >= 0)
change_num_to_use = change_num;
else
step = -1;
/* If we are stepping backwards through the changes and we have found
a change that applies, then we know this is the change to use so
we exit the loop. */
if (step == -1 && change_num_to_use != -1)
break;
change_num += step;
/* If we go past the start of the changes array, then we have no data
for this time so we return a UTC offset of 0. */
if (change_num < 0)
return 0;
if (change_num >= zone->changes->num_elements)
break;
zone_change = icalarray_element_at (zone->changes, change_num);
}
/* If we didn't find a change to use, then we have a bug! */
icalerror_assert (change_num_to_use != -1,
"No applicable timezone change found");
/* Now we know exactly which timezone change applies to the time, so
we can return the UTC offset and whether it is a daylight time. */
zone_change = icalarray_element_at (zone->changes, change_num_to_use);
if (is_daylight)
*is_daylight = zone_change->is_daylight;
return zone_change->utc_offset;
}
/* Returns the index of a timezone change which is close to the time given
in change. */
static int
icaltimezone_find_nearby_change (icaltimezone *zone,
icaltimezonechange *change)
{
icaltimezonechange *zone_change;
int lower, upper, middle, cmp;
/* Do a simple binary search. */
lower = middle = 0;
upper = zone->changes->num_elements;
while (lower < upper) {
middle = (lower + upper) >> 1;
zone_change = icalarray_element_at (zone->changes, middle);
cmp = icaltimezone_compare_change_fn (change, zone_change);
if (cmp == 0)
break;
else if (cmp < 0)
upper = middle;
else
lower = middle + 1;
}
return middle;
}
/* Adds (or subtracts) a time from a icaltimezonechange.
NOTE: This function is exactly the same as icaltime_adjust()
except for the type of the first parameter. */
static void
icaltimezone_adjust_change (icaltimezonechange *tt,
int days,
int hours,
int minutes,
int seconds)
{
int second, minute, hour, day;
int minutes_overflow, hours_overflow, days_overflow;
int days_in_month;
/* Add on the seconds. */
second = tt->second + seconds;
tt->second = second % 60;
minutes_overflow = second / 60;
if (tt->second < 0) {
tt->second += 60;
minutes_overflow--;
}
/* Add on the minutes. */
minute = tt->minute + minutes + minutes_overflow;
tt->minute = minute % 60;
hours_overflow = minute / 60;
if (tt->minute < 0) {
tt->minute += 60;
hours_overflow--;
}
/* Add on the hours. */
hour = tt->hour + hours + hours_overflow;
tt->hour = hour % 24;
days_overflow = hour / 24;
if (tt->hour < 0) {
tt->hour += 24;
days_overflow--;
}
/* Add on the days. */
day = tt->day + days + days_overflow;
if (day > 0) {
for (;;) {
days_in_month = icaltime_days_in_month (tt->month, tt->year);
if (day <= days_in_month)
break;
tt->month++;
if (tt->month >= 13) {
tt->year++;
tt->month = 1;
}
day -= days_in_month;
}
} else {
while (day <= 0) {
if (tt->month == 1) {
tt->year--;
tt->month = 12;
} else {
tt->month--;
}
day += icaltime_days_in_month (tt->month, tt->year);
}
}
tt->day = day;
}
char*
icaltimezone_get_tzid (icaltimezone *zone)
{
/* If this is a floating time, without a timezone, return NULL. */
if (!zone)
return NULL;
if (!zone->component)
icaltimezone_load_builtin_timezone (zone);
return zone->tzid;
}
char*
icaltimezone_get_location (icaltimezone *zone)
{
/* If this is a floating time, without a timezone, return NULL. */
if (!zone)
return NULL;
/* Note that for builtin timezones this comes from zones.tab so we don't
need to check the timezone is loaded here. */
return zone->location;
}
char*
icaltimezone_get_tznames (icaltimezone *zone)
{
/* If this is a floating time, without a timezone, return NULL. */
if (!zone)
return NULL;
if (!zone->component)
icaltimezone_load_builtin_timezone (zone);
return zone->tznames;
}
/* Returns the latitude of a builtin timezone. */
double
icaltimezone_get_latitude (icaltimezone *zone)
{
/* If this is a floating time, without a timezone, return 0. */
if (!zone)
return 0.0;
/* Note that for builtin timezones this comes from zones.tab so we don't
need to check the timezone is loaded here. */
return zone->latitude;
}
/* Returns the longitude of a builtin timezone. */
double
icaltimezone_get_longitude (icaltimezone *zone)
{
/* If this is a floating time, without a timezone, return 0. */
if (!zone)
return 0.0;
/* Note that for builtin timezones this comes from zones.tab so we don't
need to check the timezone is loaded here. */
return zone->longitude;
}
/* Returns the VTIMEZONE component of a timezone. */
icalcomponent*
icaltimezone_get_component (icaltimezone *zone)
{
/* If this is a floating time, without a timezone, return NULL. */
if (!zone)
return NULL;
if (!zone->component)
icaltimezone_load_builtin_timezone (zone);
return zone->component;
}
/* Sets the VTIMEZONE component of an icaltimezone, initializing the tzid,
location & tzname fields. It returns 1 on success or 0 on failure, i.e.
no TZID was found. */
int
icaltimezone_set_component (icaltimezone *zone,
icalcomponent *comp)
{
icaltimezone_reset (zone);
return icaltimezone_get_vtimezone_properties (zone, comp);
}
icalarray*
icaltimezone_array_new (void)
{
return icalarray_new (sizeof (icaltimezone), 16);
}
void
icaltimezone_array_append_from_vtimezone (icalarray *timezones,
icalcomponent *child)
{
icaltimezone zone;
icaltimezone_init (&zone);
if (icaltimezone_get_vtimezone_properties (&zone, child))
icalarray_append (timezones, &zone);
}
void
icaltimezone_array_free (icalarray *timezones)
{
icaltimezone *zone;
int i;
for (i = 0; i < timezones->num_elements; i++) {
zone = icalarray_element_at (timezones, i);
icaltimezone_free (zone, 0);
}
icalarray_free (timezones);
}
/*
* BUILTIN TIMEZONE HANDLING
*/
/* Returns an icalarray of icaltimezone structs, one for each builtin timezone.
This will load and parse the zones.tab file to get the timezone names and
their coordinates. It will not load the VTIMEZONE data for any timezones. */
icalarray*
icaltimezone_get_builtin_timezones (void)
{
if (!builtin_timezones)
icaltimezone_init_builtin_timezones ();
return builtin_timezones;
}
/* Returns a single builtin timezone, given its Olson city name. */
icaltimezone*
icaltimezone_get_builtin_timezone (const char *location)
{
icaltimezone *zone;
int lower, upper, middle, cmp;
char *zone_location;
if (!location || !location[0])
return NULL;
if (!strcmp (location, "UTC"))
return &utc_timezone;
if (!builtin_timezones)
icaltimezone_init_builtin_timezones ();
/* Do a simple binary search. */
lower = middle = 0;
upper = builtin_timezones->num_elements;
while (lower < upper) {
middle = (lower + upper) >> 1;
zone = icalarray_element_at (builtin_timezones, middle);
zone_location = icaltimezone_get_location (zone);
cmp = strcmp (location, zone_location);
if (cmp == 0)
return zone;
else if (cmp < 0)
upper = middle;
else
lower = middle + 1;
}
return NULL;
}
/* Returns a single builtin timezone, given its TZID. */
icaltimezone*
icaltimezone_get_builtin_timezone_from_tzid (const char *tzid)
{
int num_slashes = 0;
const char *p, *zone_tzid;
icaltimezone *zone;
if (!tzid || !tzid[0])
return NULL;
/* Check that the TZID starts with our unique prefix. */
if (strncmp (tzid, TZID_PREFIX, TZID_PREFIX_LEN))
return NULL;
/* Get the location, which is after the 3rd '/' character. */
p = tzid;
for (p = tzid; *p; p++) {
if (*p == '/') {
num_slashes++;
if (num_slashes == 3)
break;
}
}
if (num_slashes != 3)
return NULL;
p++;
/* Now we can use the function to get the builtin timezone from the
location string. */
zone = icaltimezone_get_builtin_timezone (p);
if (!zone)
return NULL;
/* Check that the builtin TZID matches exactly. We don't want to return
a different version of the VTIMEZONE. */
zone_tzid = icaltimezone_get_tzid (zone);
if (!strcmp (zone_tzid, tzid))
return zone;
else
return NULL;
}
/* Returns the special UTC timezone. */
icaltimezone*
icaltimezone_get_utc_timezone (void)
{
return &utc_timezone;
}
/* This initializes the builtin timezone data, i.e. the builtin_timezones
array and the special UTC timezone. It should be called before any
code that uses the timezone functions. */
static void
icaltimezone_init_builtin_timezones (void)
{
/* Initialize the special UTC timezone. */
utc_timezone.tzid = "UTC";
icaltimezone_parse_zone_tab ();
}
/* This parses the zones.tab file containing the names and locations of the
builtin timezones. It creates the builtin_timezones array which is an
icalarray of icaltimezone structs. It only fills in the location, latitude
and longtude fields; the rest are left blank. The VTIMEZONE component is
loaded later if it is needed. The timezones in the zones.tab file are
sorted by their name, which is useful for binary searches. */
static void
icaltimezone_parse_zone_tab (void)
{
char *filename;
FILE *fp;
char buf[1024]; /* Used to store each line of zones.tab as it is read. */
char location[1024]; /* Stores the city name when parsing buf. */
int filename_len;
int latitude_degrees, latitude_minutes, latitude_seconds;
int longitude_degrees, longitude_minutes, longitude_seconds;
icaltimezone zone;
icalerror_assert (builtin_timezones == NULL,
"Parsing zones.tab file multiple times");
builtin_timezones = icalarray_new (sizeof (icaltimezone), 32);
filename_len = strlen (ZONEINFO_DIRECTORY) + strlen (ZONES_TAB_FILENAME)
+ 2;
filename = (char*) malloc (filename_len);
if (!filename) {
icalerror_set_errno(ICAL_NEWFAILED_ERROR);
return;
}
snprintf (filename, filename_len, "%s/%s", ZONEINFO_DIRECTORY,
ZONES_TAB_FILENAME);
fp = fopen (filename, "r");
free (filename);
if (!fp) {
icalerror_set_errno(ICAL_FILE_ERROR);
return;
}
while (fgets (buf, sizeof(buf), fp)) {
if (*buf == '#') continue;
/* The format of each line is: "latitude longitude location". */
if (sscanf (buf, "%4d%2d%2d %4d%2d%2d %s",
&latitude_degrees, &latitude_minutes,
&latitude_seconds,
&longitude_degrees, &longitude_minutes,
&longitude_seconds,
&location) != 7) {
fprintf (stderr, "Invalid timezone description line: %s\n", buf);
continue;
}
icaltimezone_init (&zone);
zone.location = strdup (location);
if (latitude_degrees >= 0)
zone.latitude = (double) latitude_degrees
+ (double) latitude_minutes / 60
+ (double) latitude_seconds / 3600;
else
zone.latitude = (double) latitude_degrees
- (double) latitude_minutes / 60
- (double) latitude_seconds / 3600;
if (longitude_degrees >= 0)
zone.longitude = (double) longitude_degrees
+ (double) longitude_minutes / 60
+ (double) longitude_seconds / 3600;
else
zone.longitude = (double) longitude_degrees
- (double) longitude_minutes / 60
- (double) longitude_seconds / 3600;
icalarray_append (builtin_timezones, &zone);
#if 0
printf ("Found zone: %s %f %f\n",
location, zone.latitude, zone.longitude);
#endif
}
fclose (fp);
}
/* Loads the builtin VTIMEZONE data for the given timezone. */
static void
icaltimezone_load_builtin_timezone (icaltimezone *zone)
{
char *filename;
int filename_len;
FILE *fp;
icalparser *parser;
icalcomponent *comp, *subcomp;
/* If the location isn't set, it isn't a builtin timezone. */
if (!zone->location || !zone->location[0])
return;
filename_len = strlen (ZONEINFO_DIRECTORY) + strlen (zone->location) + 6;
filename = (char*) malloc (filename_len);
if (!filename) {
icalerror_set_errno(ICAL_NEWFAILED_ERROR);
return;
}
snprintf (filename, filename_len, "%s/%s.ics", ZONEINFO_DIRECTORY,
zone->location);
fp = fopen (filename, "r");
free (filename);
if (!fp) {
icalerror_set_errno(ICAL_FILE_ERROR);
return;
}
parser = icalparser_new ();
icalparser_set_gen_data (parser, fp);
comp = icalparser_parse (parser, icaltimezone_load_get_line_fn);
icalparser_free (parser);
fclose (fp);
/* Find the VTIMEZONE component inside the VCALENDAR. There should be 1. */
subcomp = icalcomponent_get_first_component (comp,
ICAL_VTIMEZONE_COMPONENT);
if (!subcomp) {
icalerror_set_errno(ICAL_PARSE_ERROR);
return;
}
icaltimezone_get_vtimezone_properties (zone, subcomp);
}
/* Callback used from icalparser_parse() */
static char *
icaltimezone_load_get_line_fn (char *s,
size_t size,
void *data)
{
return fgets (s, size, (FILE*) data);
}
/*
* DEBUGGING
*/
/*
* This outputs a list of timezone changes for the given timezone to the
* given file, up to the maximum year given. We compare this output with the
* output from 'vzic --dump-changes' to make sure that we are consistent.
* (vzic is the Olson timezone database to VTIMEZONE converter.)
*
* The output format is:
*
* Zone-Name [tab] Date [tab] Time [tab] UTC-Offset
*
* The Date and Time fields specify the time change in UTC.
*
* The UTC Offset is for local (wall-clock) time. It is the amount of time
* to add to UTC to get local time.
*/
int
icaltimezone_dump_changes (icaltimezone *zone,
int max_year,
FILE *fp)
{
static char *months[] = { "Jan", "Feb", "Mar", "Apr", "May", "Jun",
"Jul", "Aug", "Sep", "Oct", "Nov", "Dec" };
icaltimezonechange *zone_change;
int change_num;
char buffer[8];
/* Make sure the changes array is expanded up to the given time. */
icaltimezone_ensure_coverage (zone, max_year);
#if 0
printf ("Num changes: %i\n", zone->changes->num_elements);
#endif
change_num = 0;
for (change_num = 0; change_num < zone->changes->num_elements; change_num++) {
zone_change = icalarray_element_at (zone->changes, change_num);
if (zone_change->year > max_year)
break;
fprintf (fp, "%s\t%2i %s %04i\t%2i:%02i:%02i",
zone->location,
zone_change->day, months[zone_change->month - 1],
zone_change->year,
zone_change->hour, zone_change->minute, zone_change->second);
/* Wall Clock Time offset from UTC. */
format_utc_offset (zone_change->utc_offset, buffer);
fprintf (fp, "\t%s", buffer);
fprintf (fp, "\n");
}
}
/* This formats a UTC offset as "+HHMM" or "+HHMMSS".
buffer should have space for 8 characters. */
static void
format_utc_offset (int utc_offset,
char *buffer)
{
char *sign = "+";
int hours, minutes, seconds;
if (utc_offset < 0) {
utc_offset = -utc_offset;
sign = "-";
}
hours = utc_offset / 3600;
minutes = (utc_offset % 3600) / 60;
seconds = utc_offset % 60;
/* Sanity check. Standard timezone offsets shouldn't be much more than 12
hours, and daylight saving shouldn't change it by more than a few hours.
(The maximum offset is 15 hours 56 minutes at present.) */
if (hours < 0 || hours >= 24 || minutes < 0 || minutes >= 60
|| seconds < 0 || seconds >= 60) {
fprintf (stderr, "Warning: Strange timezone offset: H:%i M:%i S:%i\n",
hours, minutes, seconds);
}
if (seconds == 0)
sprintf (buffer, "%s%02i%02i", sign, hours, minutes);
else
sprintf (buffer, "%s%02i%02i%02i", sign, hours, minutes, seconds);
}
