/* Miscellaneous time-related utilities
*
* Copyright (C) 1998 The Free Software Foundation
* Copyright (C) 2000 Helix Code, Inc.
* Copyright (C) 2000 Ximian, Inc.
*
* Authors: Federico Mena <federico@ximian.com>
* Miguel de Icaza <miguel@ximian.com>
*/
#include <string.h>
#include <ctype.h>
#include <glib.h>
#include "timeutil.h"
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);
}
/**
* isodate_from_time_t:
* @t: A time value.
*
* Creates an ISO 8601 local time representation from a time value.
*
* Return value: String with the ISO 8601 representation of the local time.
**/
char *
isodate_from_time_t (time_t t)
{
struct tm *tm;
char isotime[40];
tm = localtime (&t);
strftime (isotime, sizeof (isotime)-1, "%Y%m%dT%H%M%S", tm);
return g_strdup (isotime);
}
/**
* time_from_isodate:
* @str: Date/time value in ISO 8601 format.
*
* Converts an ISO 8601 time string into a time_t value.
*
* Return value: Time_t corresponding to the specified ISO string.
**/
time_t
time_from_isodate (const char *str)
{
int len;
struct tm my_tm;
time_t t;
int 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;
memset (&my_tm, 0, sizeof (my_tm));
#define digit_at(x,y) (x[y] - '0')
my_tm.tm_year = (digit_at (str, 0) * 1000 + digit_at (str, 1) * 100 +
digit_at (str, 2) * 10 + digit_at (str, 3)) - 1900;
my_tm.tm_mon = digit_at (str, 4) * 10 + digit_at (str, 5) - 1;
my_tm.tm_mday = digit_at (str, 6) * 10 + digit_at (str, 7);
if (len > 8) {
my_tm.tm_hour = digit_at (str, 9) * 10 + digit_at (str, 10);
my_tm.tm_min = digit_at (str, 11) * 10 + digit_at (str, 12);
my_tm.tm_sec = digit_at (str, 13) * 10 + digit_at (str, 14);
}
my_tm.tm_isdst = -1;
t = mktime (&my_tm);
if (len == 16) {
#if defined(HAVE_TM_GMTOFF)
t += my_tm.tm_gmtoff;
#elif defined(HAVE_TIMEZONE)
t -= timezone;
#endif
}
return t;
}
time_t
time_add_minutes (time_t time, int minutes)
{
struct tm *tm = localtime (&time);
time_t new_time;
tm->tm_min += minutes;
if ((new_time = mktime (tm)) == -1) {
g_message ("time_add_minutes(): mktime() could not handle "
"adding %d minutes with\n", minutes);
print_time_t (time);
printf ("\n");
return time;
}
return new_time;
}
/* 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;
#if 0
int dst_flag = tm->tm_isdst;
#endif
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;
}
#if 0
/* I don't know what this is for. See also time_day_begin() and
time_day_end(). - Damon. */
if (dst_flag > tm->tm_isdst) {
tm->tm_hour++;
new_time += 3600;
} else if (dst_flag < tm->tm_isdst) {
tm->tm_hour--;
new_time -= 3600;
}
#endif
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_add_year (time_t time, int years)
{
struct tm *tm = localtime (&time);
time_t new_time;
tm->tm_year += years;
if ((new_time = mktime (tm)) == -1) {
g_message ("time_add_year(): mktime() could not handling adding %d years with\n",
years);
print_time_t (time);
printf ("\n");
return time;
}
return new_time;
}
/* Number of days in a month, for normal and leap years */
static const int days_in_month[2][12] = {
{ 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 },
{ 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }
};
/* Returns whether the specified year is a leap year */
static int
is_leap_year (int year)
{
if (year <= 1752)
return !(year % 4);
else
return (!(year % 4) && (year % 100)) || !(year % 400);
}
int
time_days_in_month (int year, int month)
{
g_return_val_if_fail (year >= 1900, 0);
g_return_val_if_fail ((month >= 0) && (month < 12), 0);
return days_in_month [is_leap_year (year)][month];
}
time_t
time_from_day (int year, int month, int day)
{
struct tm tm;
memset (&tm, 0, sizeof (tm));
tm.tm_year = year - 1900;
tm.tm_mon = month;
tm.tm_mday = day;
tm.tm_isdst = -1;
return mktime (&tm);
}
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_year_end (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_year++;
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);
}
time_t
time_month_end (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_mon++;
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 end of the week. week_start_day should use the same values
as mktime(), i.e. 0 (Sun) to 6 (Sat). */
time_t
time_week_end (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 += 7 - 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);
}
