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vzic-output.c
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/*
* Vzic - a program to convert Olson timezone database files into VZTIMEZONE
* files compatible with the iCalendar specification (RFC2445).
*
* SPDX-FileCopyrightText: 2000-2001 Ximian, Inc.
* SPDX-FileCopyrightText: 2003, Damon Chaplin <[email protected]>
*
* SPDX-License-Identifier: GPL-2.0-or-later
*
* Author: Damon Chaplin <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
*/
/* ALGORITHM:
*
* First we expand all the Rule arrays, so that each element only represents 1
* year. If a Rule extends to infinity we expand it up to a few years past the
* maximum UNTIL year used in any of the timezones. We do this to make sure
* that the last of the expanded Rules (which may be infinite) is only used
* in the last of the time periods (i.e. the last Zone line).
*
* The Rule arrays are also sorted by the start time (FROM + IN + ON + AT).
* Doing all this makes it much easier to find which rules apply to which
* periods.
*
* For each timezone (i.e. ZoneData element), we step through each of the
* time periods, the ZoneLineData elements (which represent each Zone line
* from the Olson file.)
*
* We calculate the start & end time of the period.
* - For the first line the start time is -infinity.
* - For the last line the end time is +infinity.
* - The end time of each line is also the start time of the next.
*
* We create an array of time changes which occur in this period, including
* the one implied by the Zone line itself (though this is later taken out
* if it is found to be at exactly the same time as the first Rule).
*
* Now we iterate over the time changes, outputting them as STANDARD or
* DAYLIGHT components. We also try to merge them together into RRULEs or
* use RDATEs.
*/
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include <string.h>
#include <time.h>
#include <sys/stat.h>
#include "vzic.h"
#include "vzic-output.h"
#include "vzic-dump.h"
/* These come from the Makefile. See the comments there. */
char *ProductID = PRODUCT_ID;
char *TZIDPrefix = TZID_PREFIX;
/* We expand the TZIDPrefix, replacing %D with the date, in here. */
char TZIDPrefixExpanded[1024];
/* We only use RRULEs if there are at least MIN_RRULE_OCCURRENCES occurrences,
since otherwise RDATEs are more efficient. Actually, I've set this high
so we only use RRULEs for infinite recurrences. Since expanding RRULEs is
very time-consuming, this seems sensible. */
#define MIN_RRULE_OCCURRENCES 2
/* The year we go up to when dumping the list of timezone changes (used
for testing & debugging). */
#define MAX_CHANGES_YEAR 2030
/* This is the maximum year that time_t value can typically hold on 32-bit
systems. */
#define MAX_TIME_T_YEAR 2038
/* The year we use to start RRULEs. */
#define RRULE_START_YEAR 1970
/* The year we use for RDATEs. */
#define RDATE_YEAR 1970
static char *WeekDays[] = { "SU", "MO", "TU", "WE", "TH", "FR", "SA" };
static int DaysInMonth[] = { 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 };
char *CurrentZoneName;
typedef struct _VzicTime VzicTime;
struct _VzicTime
{
/* Normal years, e.g. 2001. */
int year;
/* 0 (Jan) to 11 (Dec). */
int month;
/* The day, either a simple month day number, 1-31, or a rule such as
the last Sunday, or the first Monday on or after the 8th. */
DayCode day_code;
int day_number; /* 1 to 31. */
int day_weekday; /* 0 (Sun) to 6 (Sat). */
/* The time, in seconds from midnight. The code specifies whether the
time is a wall clock time, local standard time, or universal time. */
int time_seconds;
TimeCode time_code;
/* The offset from UTC for local standard time. */
int stdoff;
/* The offset from UTC for local wall clock time. If this is different to
stdoff then this is a DAYLIGHT component. This is TZOFFSETTO. */
int walloff;
/* TRUE if the time change recurs every year to infinity. */
gboolean is_infinite;
/* The last instance of a recurring time change, if not infinite */
VzicTime *until;
/* TRUE if the change has already been output. */
gboolean output;
/* These are the offsets of the previous VzicTime, and are used when
calculating the time of the change. We place them here in
output_zone_components() to simplify the output code. */
int prev_stdoff;
int prev_walloff;
/* The abbreviated form of the timezone name. Note that this may not be
unique. */
char *tzname;
};
static void expand_and_sort_rule_array (gpointer key,
gpointer value,
gpointer data);
static int rule_sort_func (const void *arg1,
const void *arg2);
static void output_zone (char *directory,
ZoneData *zone,
char *zone_name,
const char *alias_of,
GHashTable *rule_data);
static gboolean parse_zone_name (char *name,
char **directory,
char **subdirectory,
char **filename);
static void output_zone_to_files (ZoneData *zone,
char *zone_name,
const char *alias_of,
GHashTable *rule_data,
FILE *fp,
FILE *changes_fp);
static gboolean add_rule_changes (ZoneLineData *zone_line,
char *zone_name,
GArray *changes,
GHashTable *rule_data,
VzicTime *start,
VzicTime *end,
char **start_letter_s,
int *save_seconds);
static char* expand_tzname (char *zone_name,
char *format,
gboolean have_letter_s,
char *letter_s,
gboolean is_daylight,
int walloff);
static int compare_times (VzicTime *time1,
int stdoff1,
int walloff1,
VzicTime *time2,
int stdoff2,
int walloff2);
static gboolean times_match (VzicTime *time1,
int stdoff1,
int walloff1,
VzicTime *time2,
int stdoff2,
int walloff2);
static void output_zone_components (FILE *fp,
char *name,
const char *alias_of,
GArray *changes);
static void set_previous_offsets (GArray *changes);
static gboolean check_for_recurrence (FILE *fp,
GArray *changes,
int idx);
static void check_for_rdates (FILE *fp,
GArray *changes,
int idx);
static gboolean timezones_match (char *tzname1,
char *tzname2);
static int output_component_start (char *buffer,
VzicTime *vzictime,
gboolean output_rdate,
gboolean use_same_tz_offset);
static void output_component_end (FILE *fp,
VzicTime *vzictime);
static void vzictime_init (VzicTime *vzictime);
static int calculate_actual_time (VzicTime *vzictime,
TimeCode time_code,
int stdoff,
int walloff);
static int calculate_wall_time (int time,
TimeCode time_code,
int stdoff,
int walloff,
int *day_offset);
static int calculate_until_time (int time,
TimeCode time_code,
int stdoff,
int walloff,
int *year,
int *month,
int *day);
static void fix_time_overflow (int *year,
int *month,
int *day,
int day_offset);
static char* format_time (int year,
int month,
int day,
int time);
static char* format_tz_offset (int tz_offset,
gboolean round_seconds);
static gboolean output_rrule (char *rrule_buffer,
int month,
DayCode day_code,
int day_number,
int day_weekday,
int day_offset,
char *until);
static gboolean output_rrule_2 (char *buffer,
int month,
int day_number,
int day_weekday);
static char* format_vzictime (VzicTime *vzictime);
static void dump_changes (FILE *fp,
char *zone_name,
GArray *changes);
static void dump_change (FILE *fp,
char *zone_name,
VzicTime *vzictime,
int year);
static void expand_tzid_prefix (void);
void
output_vtimezone_files (char *directory,
GArray *zone_data,
GHashTable *rule_data,
GHashTable *link_data,
int max_until_year)
{
ZoneData *zone;
GList *links;
char *link_to;
int i;
/* Insert today's date into the TZIDs we output. */
expand_tzid_prefix ();
/* Expand the rule data so that each entry specifies only one year, and
sort it so we can easily find the rules applicable to each Zone span. */
g_hash_table_foreach (rule_data, expand_and_sort_rule_array,
GINT_TO_POINTER (max_until_year));
/* Output each timezone. */
for (i = 0; i < zone_data->len; i++) {
zone = &g_array_index (zone_data, ZoneData, i);
output_zone (directory, zone, zone->zone_name, NULL, rule_data);
/* Look for any links from this zone. */
links = g_hash_table_lookup (link_data, zone->zone_name);
while (links) {
link_to = links->data;
#if IGNORE_TOP_LEVEL_LINK
/* We ignore Links that don't have a '/' in them (things like 'EST5EDT').
*/
if (strchr (link_to, '/')) {
#endif
output_zone (directory, zone, link_to, zone->zone_name, rule_data);
#if IGNORE_TOP_LEVEL_LINK
}
#endif
links = links->next;
}
}
}
static void
expand_and_sort_rule_array (gpointer key,
gpointer value,
gpointer data)
{
char *name = key;
GArray *rule_array = value;
RuleData *rule, tmp_rule;
int len, max_year, i, from, to, year;
gboolean is_infinite;
/* We expand the rule data to a year greater than any year used in a Zone
UNTIL value. This is so that we can easily get parts of the array to
use for each Zone line. */
max_year = GPOINTER_TO_INT (data) + 2;
/* If any of the rules apply to several years, we turn it into a single rule
for each year. If the Rule is infinite we go up to max_year.
We change the FROM field in the copies of the Rule, setting it to each
of the years, and set TO to FROM, except if TO was YEAR_MAXIMUM we set
the last TO to YEAR_MAXIMUM, so we still know the Rule is infinite. */
len = rule_array->len;
for (i = 0; i < len; i++) {
rule = &g_array_index (rule_array, RuleData, i);
/* None of the Rules currently use the TYPE field, but we'd better check.
*/
if (rule->type) {
fprintf (stderr, "Rules %s has a TYPE: %s\n", name, rule->type);
exit (1);
}
if (rule->from_year != rule->to_year) {
from = rule->from_year;
to = rule->to_year;
tmp_rule = *rule;
/* Flag that this is a shallow copy so we don't free anything twice. */
tmp_rule.is_shallow_copy = TRUE;
/* See if it is an infinite Rule. */
if (to == YEAR_MAXIMUM) {
is_infinite = TRUE;
to = max_year;
if (from < to)
rule->to_year = rule->from_year;
} else {
is_infinite = FALSE;
}
/* Create a copy of the Rule for each year. */
for (year = from + 1; year <= to; year++) {
tmp_rule.from_year = year;
/* If the Rule is infinite, mark the last copy as infinite. */
if (year == to && is_infinite)
tmp_rule.to_year = YEAR_MAXIMUM;
else
tmp_rule.to_year = year;
g_array_append_val (rule_array, tmp_rule);
}
}
}
/* Now sort the rules. */
qsort (rule_array->data, rule_array->len, sizeof (RuleData), rule_sort_func);
#if 0
dump_rule_array (name, rule_array, stdout);
#endif
}
/* This is used to sort the rules, after the rules have all been expanded so
that each one is only for one year. */
static int
rule_sort_func (const void *arg1,
const void *arg2)
{
RuleData *rule1, *rule2;
int time1_year, time1_month, time1_day;
int time2_year, time2_month, time2_day;
int month_diff, result;
VzicTime t1, t2;
rule1 = (RuleData*) arg1;
rule2 = (RuleData*) arg2;
time1_year = rule1->from_year;
time1_month = rule1->in_month;
time2_year = rule2->from_year;
time2_month = rule2->in_month;
/* If there is more that one month difference we don't need to calculate
the day or time. */
month_diff = (time1_year - time2_year) * 12 + time1_month - time2_month;
if (month_diff > 1)
return 1;
if (month_diff < -1)
return -1;
/* Now we have to calculate the day and time of the Rule start and the
VzicTime, using the given offsets. */
t1.year = time1_year;
t1.month = time1_month;
t1.day_code = rule1->on_day_code;
t1.day_number = rule1->on_day_number;
t1.day_weekday = rule1->on_day_weekday;
t1.time_code = rule1->at_time_code;
t1.time_seconds = rule1->at_time_seconds;
t2.year = time2_year;
t2.month = time2_month;
t2.day_code = rule2->on_day_code;
t2.day_number = rule2->on_day_number;
t2.day_weekday = rule2->on_day_weekday;
t2.time_code = rule2->at_time_code;
t2.time_seconds = rule2->at_time_seconds;
/* FIXME: We don't know the offsets yet, but I don't think any Rules are
close enough together that the offsets can make a difference. Should
check this. */
calculate_actual_time (&t1, TIME_WALL, 0, 0);
calculate_actual_time (&t2, TIME_WALL, 0, 0);
/* Now we can compare the entire time. */
if (t1.year > t2.year)
result = 1;
else if (t1.year < t2.year)
result = -1;
else if (t1.month > t2.month)
result = 1;
else if (t1.month < t2.month)
result = -1;
else if (t1.day_number > t2.day_number)
result = 1;
else if (t1.day_number < t2.day_number)
result = -1;
else if (t1.time_seconds > t2.time_seconds)
result = 1;
else if (t1.time_seconds < t2.time_seconds)
result = -1;
else {
printf ("WARNING: Rule dates matched.\n");
result = 0;
}
return result;
}
static void
output_zone (char *directory,
ZoneData *zone,
char *zone_name,
const char *alias_of,
GHashTable *rule_data)
{
FILE *fp, *changes_fp = NULL;
char output_directory[PATHNAME_BUFFER_SIZE];
char filename[PATHNAME_BUFFER_SIZE];
char changes_filename[PATHNAME_BUFFER_SIZE];
char *zone_directory, *zone_subdirectory, *zone_filename;
/* Set a global for the zone_name, to be used only for debug messages. */
CurrentZoneName = zone_name;
/* Use this to only output a particular zone. */
#if 0
if (strcmp (zone_name, "Atlantic/Azores"))
return;
#endif
#if 0
printf ("Outputting Zone: %s\n", zone_name);
#endif
if (!parse_zone_name (zone_name, &zone_directory, &zone_subdirectory,
&zone_filename))
return;
if (VzicDumpZoneNamesAndCoords) {
VzicTimeZoneNames = g_list_prepend (VzicTimeZoneNames,
g_strdup (zone_name));
}
if (zone_subdirectory) {
sprintf (output_directory, "%s/%s/%s", directory, zone_directory,
zone_subdirectory);
ensure_directory_exists (output_directory);
sprintf (filename, "%s/%s.ics", output_directory, zone_filename);
if (VzicDumpChanges) {
sprintf (output_directory, "%s/ChangesVzic/%s/%s", directory,
zone_directory, zone_subdirectory);
ensure_directory_exists (output_directory);
sprintf (changes_filename, "%s/%s", output_directory, zone_filename);
}
}
else if (zone_directory) {
sprintf (output_directory, "%s/%s", directory, zone_directory);
ensure_directory_exists (output_directory);
sprintf (filename, "%s/%s.ics", output_directory, zone_filename);
if (VzicDumpChanges) {
sprintf (output_directory, "%s/ChangesVzic/%s", directory, zone_directory);
ensure_directory_exists (output_directory);
sprintf (changes_filename, "%s/%s", output_directory, zone_filename);
}
}
else {
sprintf (output_directory, "%s", directory);
ensure_directory_exists (output_directory);
sprintf (filename, "%s/%s.ics", output_directory, zone_filename);
if (VzicDumpChanges) {
sprintf (output_directory, "%s/ChangesVzic", directory);
ensure_directory_exists (output_directory);
sprintf (changes_filename, "%s/%s", output_directory, zone_filename);
}
}
/* Create the files. */
fp = fopen (filename, "w");
if (!fp) {
fprintf (stderr, "Couldn't create file: %s\n", filename);
exit (1);
}
if (VzicDumpChanges) {
changes_fp = fopen (changes_filename, "w");
if (!changes_fp) {
fprintf (stderr, "Couldn't create file: %s\n", changes_filename);
exit (1);
}
}
fprintf (fp, "BEGIN:VCALENDAR\r\nPRODID:%s\r\nVERSION:2.0\r\n", ProductID);
output_zone_to_files (zone, zone_name, alias_of, rule_data, fp, changes_fp);
if (ferror (fp)) {
fprintf (stderr, "Error writing file: %s\n", filename);
exit (1);
}
fprintf (fp, "END:VCALENDAR\r\n");
fclose (fp);
g_free (zone_directory);
g_free (zone_subdirectory);
g_free (zone_filename);
}
/* This checks that the Zone name only uses the characters in [-+_/a-zA-Z0-9],
and outputs a warning if it isn't. */
static gboolean
parse_zone_name (char *name,
char **directory,
char **subdirectory,
char **filename)
{
static int invalid_zone_num = 1;
char *p, ch, *first_slash_pos = NULL, *second_slash_pos = NULL;
gboolean invalid = FALSE;
for (p = name; (ch = *p) != 0; p++) {
if ((ch < 'a' || ch > 'z') && (ch < 'A' || ch > 'Z')
&& (ch < '0' || ch > '9') && ch != '/' && ch != '_'
&& ch != '-' && ch != '+') {
fprintf (stderr, "WARNING: Unusual Zone name: %s\n", name);
invalid = TRUE;
break;
}
if (ch == '/') {
if (!first_slash_pos) {
first_slash_pos = p;
} else if (!second_slash_pos) {
second_slash_pos = p;
} else {
fprintf (stderr, "WARNING: More than 2 '/' characters in Zone name: %s\n", name);
invalid = TRUE;
break;
}
}
}
#if 0
if (!first_slash_pos) {
#if 0
fprintf (stderr, "No '/' character in Zone name: %s. Skipping.\n", name);
#endif
return FALSE;
}
#endif
if (invalid) {
*directory = g_strdup ("Invalid");
*filename = g_strdup_printf ("Zone%i", invalid_zone_num++);
} else if (!first_slash_pos) {
*directory = NULL;
*subdirectory = NULL;
*filename = g_strdup (name);
} else {
*first_slash_pos = '\0';
*directory = g_strdup (name);
*first_slash_pos = '/';
if (second_slash_pos) {
*second_slash_pos = '\0';
*subdirectory = g_strdup (first_slash_pos + 1);
*second_slash_pos = '/';
*filename = g_strdup (second_slash_pos + 1);
} else {
*subdirectory = NULL;
*filename = g_strdup (first_slash_pos + 1);
}
}
return invalid ? FALSE : TRUE;
}
static void
output_zone_to_files (ZoneData *zone,
char *zone_name,
const char *alias_of,
GHashTable *rule_data,
FILE *fp,
FILE *changes_fp)
{
ZoneLineData *zone_line;
GArray *changes;
int i, stdoff, walloff, start_index, save_seconds;
VzicTime start, end, *vzictime_start, *vzictime, *vzictime_first_rule_change;
gboolean is_daylight, found_letter_s;
char *start_letter_s;
changes = g_array_new (FALSE, FALSE, sizeof (VzicTime));
vzictime_init (&start);
vzictime_init (&end);
/* The first period starts at -infinity. */
start.year = YEAR_MINIMUM;
for (i = 0; i < zone->zone_line_data->len; i++) {
zone_line = &g_array_index (zone->zone_line_data, ZoneLineData, i);
if (i == 0) start.is_infinite = (zone_line->rules == NULL);
/* This is the local standard time offset from GMT for this period. */
start.stdoff = stdoff = zone_line->stdoff_seconds;
start.walloff = walloff = stdoff + zone_line->save_seconds;
if (zone_line->until_set) {
end.year = zone_line->until_year;
end.month = zone_line->until_month;
end.day_code = zone_line->until_day_code;
end.day_number = zone_line->until_day_number;
end.day_weekday = zone_line->until_day_weekday;
end.time_seconds = zone_line->until_time_seconds;
end.time_code = zone_line->until_time_code;
} else {
/* The last period ends at +infinity. */
end.year = YEAR_MAXIMUM;
}
/* Add a time change for the start of the period. This may be removed
later if one of the rules expands to exactly the same time. */
start_index = changes->len;
g_array_append_val (changes, start);
/* If there are Rules associated with this period, add all the relevant
time changes. */
save_seconds = 0;
if (zone_line->rules)
found_letter_s = add_rule_changes (zone_line, zone_name, changes,
rule_data, &start, &end,
&start_letter_s, &save_seconds);
else
found_letter_s = FALSE;
/* FIXME: I'm not really sure what to do about finding a LETTER_S for the
first part of the period (i.e. before the first Rule comes into effect).
Currently we try to use the same LETTER_S as the first Rule of the
period which is in local standard time. */
if (zone_line->save_seconds)
save_seconds = zone_line->save_seconds;
is_daylight = save_seconds ? TRUE : FALSE;
vzictime_start = &g_array_index (changes, VzicTime, start_index);
walloff = vzictime_start->walloff = stdoff + save_seconds;
/* TEST: See if the first Rule time is exactly the same as the change from
the Zone line. In which case we can remove the Zone line change. */
if (changes->len > start_index + 1) {
int prev_stdoff, prev_walloff;
if (start_index > 0) {
VzicTime *v = &g_array_index (changes, VzicTime, start_index - 1);
prev_stdoff = v->stdoff;
prev_walloff = v->walloff;
} else {
prev_stdoff = 0;
prev_walloff = 0;
}
vzictime_first_rule_change = &g_array_index (changes, VzicTime,
start_index + 1);
if (times_match (vzictime_start, prev_stdoff, prev_walloff,
vzictime_first_rule_change, stdoff, walloff)) {
#if 0
printf ("Removing zone-line change (using new offsets)\n");
#endif
g_array_remove_index (changes, start_index);
vzictime_start = NULL;
} else if (times_match (vzictime_start, prev_stdoff, prev_walloff,
vzictime_first_rule_change, prev_stdoff, prev_walloff)) {
#if 0
printf ("Removing zone-line change (using previous offsets)\n");
#endif
g_array_remove_index (changes, start_index);
vzictime_start = NULL;
}
}
if (vzictime_start) {
vzictime_start->tzname = expand_tzname (zone_name, zone_line->format,
found_letter_s,
start_letter_s, is_daylight, vzictime_start->walloff);
}
/* The start of the next Zone line is the end time of this one. */
start = end;
}
set_previous_offsets (changes);
output_zone_components (fp, zone_name, alias_of, changes);
if (VzicDumpChanges)
dump_changes (changes_fp, zone_name, changes);
/* Free all the TZNAME fields. */
for (i = 0; i < changes->len; i++) {
vzictime = &g_array_index (changes, VzicTime, i);
g_free (vzictime->tzname);
}
g_array_free (changes, TRUE);
}
/* This appends any timezone changes specified by the rules associated with
the timezone, that happen between the start and end times.
It returns the letter_s field of the first STANDARD rule found in the
search. We need this to fill in any %s in the FORMAT field of the first
component of the time period (the Zone line). */
static gboolean
add_rule_changes (ZoneLineData *zone_line,
char *zone_name,
GArray *changes,
GHashTable *rule_data,
VzicTime *start,
VzicTime *end,
char **start_letter_s,
int *save_seconds)
{
GArray *rule_array;
RuleData *rule, *prev_rule = NULL;
int stdoff, walloff, i, prev_stdoff, prev_walloff;
VzicTime vzictime;
gboolean is_daylight, found_start_letter_s = FALSE;
gboolean checked_for_previous = FALSE;
*save_seconds = 0;
rule_array = g_hash_table_lookup (rule_data, zone_line->rules);
if (!rule_array) {
fprintf (stderr, "Couldn't access rules: %s\n", zone_line->rules);
exit (1);
}
/* The stdoff is the same for all the rules. */
stdoff = start->stdoff;
/* The walloff changes as we go through the rules. */
walloff = start->walloff;
/* Get the stdoff & walloff from the last change before this period. */
if (changes->len >= 2) {
VzicTime *change = &g_array_index (changes, VzicTime, changes->len - 2);
prev_stdoff = change->stdoff;
prev_walloff = change->walloff;
} else {
prev_stdoff = prev_walloff = 0;
}
for (i = 0; i < rule_array->len; i++) {
int r;
rule = &g_array_index (rule_array, RuleData, i);
is_daylight = rule->save_seconds != 0 ? TRUE : FALSE;
vzictime_init (&vzictime);
vzictime.year = rule->from_year;
vzictime.month = rule->in_month;
vzictime.day_code = rule->on_day_code;
vzictime.day_number = rule->on_day_number;
vzictime.day_weekday = rule->on_day_weekday;
vzictime.time_seconds = rule->at_time_seconds;
vzictime.time_code = rule->at_time_code;
vzictime.stdoff = stdoff;
vzictime.walloff = stdoff + rule->save_seconds;
vzictime.is_infinite = (rule->to_year == YEAR_MAXIMUM) ? TRUE : FALSE;
/* If the rule time is before or on the given start time, skip it. */
r = compare_times (&vzictime, stdoff, walloff,
start, prev_stdoff, prev_walloff);
if (r <= 0) {
/* Our next rule may start while this one is in effect
so we keep track of its name.
This seems to eliminate the need to guess in expand_tzname()
but hasn't had enough testing to prove foolproof as of yet. */
found_start_letter_s = TRUE;
*start_letter_s = rule->letter_s;
if (r == 0 && vzictime.time_code != start->time_code) {
/* Rule time is on the given start time.
We want to keep the rule time (for the time_code) but we need to
adjust the time to be based on the last change before this period */
if (vzictime.time_code == TIME_WALL) {
/* Adjust for rule possibly starting during DST */
vzictime.time_seconds += prev_walloff - walloff;
}
else if (vzictime.time_code == TIME_STANDARD) {
/* Adjust for rule possibly starting at UTC change */
vzictime.time_seconds += prev_stdoff - stdoff;
}
}
else continue;
}
/* If the previous Rule was a daylight Rule, then we may want to use the
walloff from that. */
if (!checked_for_previous) {
checked_for_previous = TRUE;
if (i > 0) {
prev_rule = &g_array_index (rule_array, RuleData, i - 1);
if (prev_rule->save_seconds) {
walloff = start->walloff = stdoff + prev_rule->save_seconds;
*save_seconds = prev_rule->save_seconds;
found_start_letter_s = TRUE;
*start_letter_s = prev_rule->letter_s;
#if 0
printf ("Could use save_seconds from previous Rule: %s\n",
zone_name);
#endif
}
}
}
/* If an end time has been given, then if the rule time is on or after it
break out of the loop. */
if (end->year != YEAR_MAXIMUM
&& compare_times (&vzictime, stdoff, walloff,
end, stdoff, walloff) >= 0)
break;
vzictime.tzname = expand_tzname (zone_name, zone_line->format, TRUE,
rule->letter_s, is_daylight, vzictime.walloff);
g_array_append_val (changes, vzictime);
/* When we find the first STANDARD time we set letter_s. */
if (!found_start_letter_s && !is_daylight) {
found_start_letter_s = TRUE;
*start_letter_s = rule->letter_s;
}
/* Now that we have added the Rule, the new walloff comes into effect
for any following Rules. */
walloff = vzictime.walloff;
}
/* If last Rule is terminating, flag it */
if (end->year == YEAR_MAXIMUM &&
rule->to_year >= 2037 && rule->to_year < YEAR_MAXIMUM) {
VzicTime *v = &g_array_index (changes, VzicTime, changes->len - 1);
v->until = v;
}
return found_start_letter_s;
}
/* This expands the Zone line FORMAT field, using the given LETTER_S from a
Rule line. There are 4 types of FORMAT field:
1. the string "%z". The string is replaced by the UT offset, e.g., '-07' for
seven hours behind UT and '+0530' for five hours and thirty minutes
ahead.
2. a string with an %s in, e.g. "WE%sT". The %s is replaced with LETTER_S.
3. a string with an '/' in, e.g. "CAT/CAWT". The first part is used for
standard time and the second part for when daylight-saving is in effect.
4. a plain string, e.g. "LMT", which we leave as-is.
Note that (2) is the only type in which letter_s is required.
*/
static char*
expand_tzname (char *zone_name,
char *format,
gboolean have_letter_s,
char *letter_s,
gboolean is_daylight,
int walloff)
{
char *p, buffer[256], *guess = NULL;
int len;
#if 0
printf ("Expanding %s with %s\n", format, letter_s);
#endif
if (!format || !format[0]) {
fprintf (stderr, "Missing FORMAT\n");
exit (1);
}
/* 1. Look for "%z" */
if (strcmp(format, "%z") == 0) {
if (walloff % 3600 == 0)
sprintf(buffer, "%+03d", walloff / 3600);
else
sprintf(buffer, "%+03d%02d", walloff / 3600, abs(walloff) / 60 % 60);
return g_strdup(buffer);
}
/* 2. Look for a "%s". */
p = strchr (format, '%');
if (p && *(p + 1) == 's') {
if (!have_letter_s) {
/* NOTE: These are a few hard-coded TZNAMEs that I've looked up myself.
These are needed in a few places where a Zone line comes into effect
but no Rule has been found, so we have no LETTER_S to use.
I've tried to use whatever is the normal LETTER_S in the Rules for
the particular zone, in local standard time. */
if (!strcmp (zone_name, "Asia/Macao")
&& !strcmp (format, "C%sT"))
guess = "CST";
else if (!strcmp (zone_name, "Asia/Macau")
&& !strcmp (format, "C%sT"))
guess = "CST";
else if (!strcmp (zone_name, "Asia/Ashgabat")
&& !strcmp (format, "ASH%sT"))
guess = "ASHT";
else if (!strcmp (zone_name, "Asia/Ashgabat")
&& !strcmp (format, "TM%sT"))
guess = "TMT";
else if (!strcmp (zone_name, "Asia/Samarkand")
&& !strcmp (format, "TAS%sT"))
guess = "TAST";
else if (!strcmp (zone_name, "Atlantic/Azores")
&& !strcmp (format, "WE%sT"))
guess = "WET";