/* Miscellaneous time-related utilities
*
* Copyright (C) 1998 The Free Software Foundation
* Copyright (C) 2000 Ximian, Inc.
*
* Authors: Federico Mena <federico@ximian.com>
* Miguel de Icaza <miguel@ximian.com>
* Damon Chaplin <damon@ximian.com>
*/
#include <string.h>
#include <ctype.h>
#include <glib.h>
#include <ical.h>
#include "timeutil.h"
#define REFORMATION_DAY 639787 /* First day of the reformation, counted from 1 Jan 1 */
#define MISSING_DAYS 11 /* They corrected out 11 days */
#define THURSDAY 4 /* First day of reformation */
#define SATURDAY 6 /* Offset value; 1 Jan 1 was a Saturday */
/* Number of days in a month, using 0 (Jan) to 11 (Dec). For leap years,
add 1 to February (month 1). */
static const int days_in_month[12] = {
31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31
};
/**************************************************************************
* time_t manipulation functions.
*
* NOTE: these use the Unix timezone functions like mktime() and localtime()
* and so should not be used in Evolution. New Evolution code should use
* icaltimetype values rather than time_t values wherever possible.
**************************************************************************/
static void
print_time_t (time_t t)
{
struct tm *tm = localtime (&t);
printf ("%d/%02d/%02d %02d:%02d:%02d",
1900 + tm->tm_year, tm->tm_mon+1, tm->tm_mday,
tm->tm_hour, tm->tm_min, tm->tm_sec);
}
/* Adds a day onto the time, using local time.
Note that if clocks go forward due to daylight savings time, there are
some non-existent local times, so the hour may be changed to make it a
valid time. This also means that it may not be wise to keep calling
time_add_day() to step through a certain period - if the hour gets changed
to make it valid time, any further calls to time_add_day() will also return
this hour, which may not be what you want. */
time_t
time_add_day (time_t time, int days)
{
struct tm *tm = localtime (&time);
time_t new_time;
tm->tm_mday += days;
tm->tm_isdst = -1;
if ((new_time = mktime (tm)) == -1) {
g_message ("time_add_day(): mktime() could not handling adding %d days with\n",
days);
print_time_t (time);
printf ("\n");
return time;
}
return new_time;
}
time_t
time_add_week (time_t time, int weeks)
{
return time_add_day (time, weeks * 7);
}
time_t
time_add_month (time_t time, int months)
{
struct tm *tm = localtime (&time);
time_t new_time;
int mday;
mday = tm->tm_mday;
tm->tm_mon += months;
tm->tm_isdst = -1;
if ((new_time = mktime (tm)) == -1) {
g_message ("time_add_month(): mktime() could not handling adding %d months with\n",
months);
print_time_t (time);
printf ("\n");
return time;
}
tm = localtime (&new_time);
if (tm->tm_mday < mday) {
tm->tm_mon--;
tm->tm_mday = time_days_in_month (tm->tm_year+1900, tm->tm_mon);
return new_time = mktime (tm);
}
else
return new_time;
}
time_t
time_year_begin (time_t t)
{
struct tm tm;
tm = *localtime (&t);
tm.tm_hour = 0;
tm.tm_min = 0;
tm.tm_sec = 0;
tm.tm_mon = 0;
tm.tm_mday = 1;
tm.tm_isdst = -1;
return mktime (&tm);
}
time_t
time_month_begin (time_t t)
{
struct tm tm;
tm = *localtime (&t);
tm.tm_hour = 0;
tm.tm_min = 0;
tm.tm_sec = 0;
tm.tm_mday = 1;
tm.tm_isdst = -1;
return mktime (&tm);
}
/* Returns the start of the week. week_start_day should use the same values
as mktime(), i.e. 0 (Sun) to 6 (Sat). */
time_t
time_week_begin (time_t t, int week_start_day)
{
struct tm tm;
int offset;
tm = *localtime (&t);
/* Calculate the current offset from the week start day. */
offset = (tm.tm_wday + 7 - week_start_day) % 7;
tm.tm_hour = 0;
tm.tm_min = 0;
tm.tm_sec = 0;
tm.tm_mday -= offset;
tm.tm_isdst = -1;
return mktime (&tm);
}
/* Returns the start of the day, according to the local time. */
time_t
time_day_begin (time_t t)
{
struct tm tm;
tm = *localtime (&t);
tm.tm_hour = 0;
tm.tm_min = 0;
tm.tm_sec = 0;
tm.tm_isdst = -1;
return mktime (&tm);
}
/* Returns the end of the day, according to the local time. */
time_t
time_day_end (time_t t)
{
struct tm tm;
tm = *localtime (&t);
tm.tm_mday++;
tm.tm_hour = 0;
tm.tm_min = 0;
tm.tm_sec = 0;
tm.tm_isdst = -1;
return mktime (&tm);
}
/**************************************************************************
* time_t manipulation functions, using timezones in libical.
*
* NOTE: these are only here to make the transition to the timezone
* functions easier. New code should use icaltimetype values rather than
* time_t values wherever possible.
**************************************************************************/
/* Adds or subtracts a number of days to/from the given time_t value, using
the given timezone.
NOTE: this function is only here to make the transition to the timezone
functions easier. New code should use icaltimetype values and
icaltime_adjust() to add or subtract days, hours, minutes & seconds. */
time_t
time_add_day_with_zone (time_t time, int days, icaltimezone *zone)
{
struct icaltimetype tt;
/* Convert to an icaltimetype. */
tt = icaltime_from_timet_with_zone (time, FALSE, zone);
/* Add/subtract the number of days. */
icaltime_adjust (&tt, days, 0, 0, 0);
/* Convert back to a time_t. */
return icaltime_as_timet_with_zone (tt, zone);
}
/* Adds or subtracts a number of weeks to/from the given time_t value, using
the given timezone.
NOTE: this function is only here to make the transition to the timezone
functions easier. New code should use icaltimetype values and
icaltime_adjust() to add or subtract days, hours, minutes & seconds. */
time_t
time_add_week_with_zone (time_t time, int weeks, icaltimezone *zone)
{
return time_add_day_with_zone (time, weeks * 7, zone);
}
/* Adds or subtracts a number of months to/from the given time_t value, using
the given timezone.
NOTE: this function is only here to make the transition to the timezone
functions easier. New code should use icaltimetype values and
icaltime_adjust() to add or subtract days, hours, minutes & seconds. */
time_t
time_add_month_with_zone (time_t time, int months, icaltimezone *zone)
{
struct icaltimetype tt;
/* Convert to an icaltimetype. */
tt = icaltime_from_timet_with_zone (time, FALSE, zone);
/* Add on the number of months. */
tt.month += months;
/* Normalize it, fixing any overflow. */
tt = icaltime_normalize (tt);
/* Convert back to a time_t. */
return icaltime_as_timet_with_zone (tt, zone);
}
/* Returns the start of the year containing the given time_t, using the given
timezone.
NOTE: this function is only here to make the transition to the timezone
functions easier. New code should use icaltimetype values and
icaltime_adjust() to add or subtract days, hours, minutes & seconds. */
time_t
time_year_begin_with_zone (time_t time, icaltimezone *zone)
{
struct icaltimetype tt;
/* Convert to an icaltimetype. */
tt = icaltime_from_timet_with_zone (time, FALSE, zone);
/* Set it to the start of the year. */
tt.month = 1;
tt.day = 1;
tt.hour = 0;
tt.minute = 0;
tt.second = 0;
/* Convert back to a time_t. */
return icaltime_as_timet_with_zone (tt, zone);
}
/* Returns the start of the month containing the given time_t, using the given
timezone.
NOTE: this function is only here to make the transition to the timezone
functions easier. New code should use icaltimetype values and
icaltime_adjust() to add or subtract days, hours, minutes & seconds. */
time_t
time_month_begin_with_zone (time_t time, icaltimezone *zone)
{
struct icaltimetype tt;
/* Convert to an icaltimetype. */
tt = icaltime_from_timet_with_zone (time, FALSE, zone);
/* Set it to the start of the month. */
tt.day = 1;
tt.hour = 0;
tt.minute = 0;
tt.second = 0;
/* Convert back to a time_t. */
return icaltime_as_timet_with_zone (tt, zone);
}
/* Returns the start of the week containing the given time_t, using the given
timezone. week_start_day should use the same values as mktime(),
i.e. 0 (Sun) to 6 (Sat).
NOTE: this function is only here to make the transition to the timezone
functions easier. New code should use icaltimetype values and
icaltime_adjust() to add or subtract days, hours, minutes & seconds. */
time_t
time_week_begin_with_zone (time_t time, int week_start_day, icaltimezone *zone)
{
struct icaltimetype tt;
int weekday, offset;
/* Convert to an icaltimetype. */
tt = icaltime_from_timet_with_zone (time, FALSE, zone);
/* Get the weekday. */
weekday = time_day_of_week (tt.day, tt.month - 1, tt.year);
/* Calculate the current offset from the week start day. */
offset = (weekday + 7 - week_start_day) % 7;
/* Set it to the start of the month. */
tt.day -= offset;
tt.hour = 0;
tt.minute = 0;
tt.second = 0;
/* Normalize it, to fix any overflow. */
tt = icaltime_normalize (tt);
/* Convert back to a time_t. */
return icaltime_as_timet_with_zone (tt, zone);
}
/* Returns the start of the day containing the given time_t, using the given
timezone.
NOTE: this function is only here to make the transition to the timezone
functions easier. New code should use icaltimetype values and
icaltime_adjust() to add or subtract days, hours, minutes & seconds. */
time_t
time_day_begin_with_zone (time_t time, icaltimezone *zone)
{
struct icaltimetype tt;
/* Convert to an icaltimetype. */
tt = icaltime_from_timet_with_zone (time, FALSE, zone);
/* Set it to the start of the day. */
tt.hour = 0;
tt.minute = 0;
tt.second = 0;
/* Convert back to a time_t. */
return icaltime_as_timet_with_zone (tt, zone);
}
/* Returns the end of the day containing the given time_t, using the given
timezone. (The end of the day is the start of the next day.)
NOTE: this function is only here to make the transition to the timezone
functions easier. New code should use icaltimetype values and
icaltime_adjust() to add or subtract days, hours, minutes & seconds. */
time_t
time_day_end_with_zone (time_t time, icaltimezone *zone)
{
struct icaltimetype tt;
/* Convert to an icaltimetype. */
tt = icaltime_from_timet_with_zone (time, FALSE, zone);
/* Set it to the start of the next day. */
tt.day++;
tt.hour = 0;
tt.minute = 0;
tt.second = 0;
/* Normalize it, to fix any overflow. */
tt = icaltime_normalize (tt);
/* Convert back to a time_t. */
return icaltime_as_timet_with_zone (tt, zone);
}
/**
* time_to_gdate_with_zone:
* @date: Destination #GDate value.
* @time: A time value.
* @zone: Desired timezone for destination @date, or NULL if the UTC timezone
* is desired.
*
* Converts a time_t value to a #GDate structure using the specified timezone.
* This is analogous to g_date_set_time() but takes the timezone into account.
**/
void
time_to_gdate_with_zone (GDate *date, time_t time, icaltimezone *zone)
{
struct icaltimetype tt;
g_return_if_fail (date != NULL);
g_return_if_fail (time != -1);
tt = icaltime_from_timet_with_zone (time, FALSE,
zone ? zone : icaltimezone_get_utc_timezone ());
g_date_set_dmy (date, tt.day, tt.month, tt.year);
}
/**************************************************************************
* General time functions.
**************************************************************************/
/* Returns the number of days in the month. Year is the normal year, e.g. 2001.
Month is 0 (Jan) to 11 (Dec). */
int
time_days_in_month (int year, int month)
{
int days;
g_return_val_if_fail (year >= 1900, 0);
g_return_val_if_fail ((month >= 0) && (month < 12), 0);
days = days_in_month[month];
if (month == 1 && time_is_leap_year (year))
days++;
return days;
}
/* Returns the 1-based day number within the year of the specified date.
Year is the normal year, e.g. 2001. Month is 0 to 11. */
int
time_day_of_year (int day, int month, int year)
{
int i;
for (i = 0; i < month; i++) {
day += days_in_month[i];
if (month == 1 && time_is_leap_year (year))
day++;
}
return day;
}
/* Returns the day of the week for the specified date, 0 (Sun) to 6 (Sat).
For the days that were removed on the Gregorian reformation, it returns
Thursday. Year is the normal year, e.g. 2001. Month is 0 to 11. */
int
time_day_of_week (int day, int month, int year)
{
int n;
n = (year - 1) * 365 + time_leap_years_up_to (year - 1)
+ time_day_of_year (day, month, year);
if (n < REFORMATION_DAY)
return (n - 1 + SATURDAY) % 7;
if (n >= (REFORMATION_DAY + MISSING_DAYS))
return (n - 1 + SATURDAY - MISSING_DAYS) % 7;
return THURSDAY;
}
/* Returns whether the specified year is a leap year. Year is the normal year,
e.g. 2001. */
gboolean
time_is_leap_year (int year)
{
if (year <= 1752)
return !(year % 4);
else
return (!(year % 4) && (year % 100)) || !(year % 400);
}
/* Returns the number of leap years since year 1 up to (but not including) the
specified year. Year is the normal year, e.g. 2001. */
int
time_leap_years_up_to (int year)
{
/* There is normally a leap year every 4 years, except at the turn of
centuries since 1700. But there is a leap year on centuries since 1700
which are divisible by 400. */
return (year / 4
- ((year > 1700) ? (year / 100 - 17) : 0)
+ ((year > 1600) ? ((year - 1600) / 400) : 0));
}
/**
* isodate_from_time_t:
* @t: A time value.
*
* Creates an ISO 8601 UTC representation from a time value.
*
* Return value: String with the ISO 8601 representation of the UTC time.
**/
char *
isodate_from_time_t (time_t t)
{
struct tm *tm;
char isotime[40];
tm = gmtime (&t);
strftime (isotime, sizeof (isotime)-1, "%Y%m%dT%H%M%SZ", tm);
return g_strdup (isotime);
}
/**
* time_from_isodate:
* @str: Date/time value in ISO 8601 format.
*
* Converts an ISO 8601 UTC time string into a time_t value.
*
* Return value: Time_t corresponding to the specified ISO string.
* Note that we only allow UTC times at present.
**/
time_t
time_from_isodate (const char *str)
{
struct icaltimetype tt = icaltime_null_time ();
icaltimezone *utc_zone;
int len, i;
g_return_val_if_fail (str != NULL, -1);
/* yyyymmdd[Thhmmss[Z]] */
len = strlen (str);
if (!(len == 8 || len == 15 || len == 16))
return -1;
for (i = 0; i < len; i++)
if (!((i != 8 && i != 15 && isdigit (str[i]))
|| (i == 8 && str[i] == 'T')
|| (i == 15 && str[i] == 'Z')))
return -1;
#define digit_at(x,y) (x[y] - '0')
tt.year = digit_at (str, 0) * 1000
+ digit_at (str, 1) * 100
+ digit_at (str, 2) * 10
+ digit_at (str, 3);
tt.month = digit_at (str, 4) * 10
+ digit_at (str, 5);
tt.day = digit_at (str, 6) * 10
+ digit_at (str, 7);
if (len > 8) {
tt.hour = digit_at (str, 9) * 10
+ digit_at (str, 10);
tt.minute = digit_at (str, 11) * 10
+ digit_at (str, 12);
tt.second = digit_at (str, 13) * 10
+ digit_at (str, 14);
}
utc_zone = icaltimezone_get_utc_timezone ();
return icaltime_as_timet_with_zone (tt, utc_zone);
}
