/*
* check the existence of given calendar elements
* this includes either number of day in the month
* and calendars pecularities (year 0 and October 1582)
*/
static int check_date(int century, int wy,
Int_token y, Int_token m, Int_token d,
long *jul)
{
int y_expand, y_check, m_check, d_check;
/* expands years written with two digits only */
if (y.value >= 0 && y.value < wy && y.digits <= 2) {
y_expand = century + y.value;
} else if (y.value >= wy && y.value < 100 && y.digits <= 2) {
y_expand = century - 100 + y.value;
} else {
y_expand = y.value;
}
if (m.digits > 2 || d.digits > 2) {
/* this should be the year instead of either the month or the day */
return EXIT_FAILURE;
}
*jul = cal_to_jul(y_expand, m.value, d.value);
jul_to_cal(*jul, &y_check, &m_check, &d_check);
if (y_expand != y_check || m.value != m_check || d.value != d_check) {
return EXIT_FAILURE;
} else {
return EXIT_SUCCESS;
}
}
/*
* convert julian day to calendar and hourly elements
* rounding_tol allows to say 1999-12-31T23:59:59.501
* should be rounded to 2000-01-01T00:00:00.000 assuming
* it is set to 0.5 second. It is wise to set it according
* to the display accuracy of seconds.
*/
void jul_to_cal_and_time(double jday, double rounding_tol,
int *y, int *m, int *d,
int *hour, int *min, double *sec)
{
long n;
/* find the time of the day */
n = (long) floor(jday + 0.5);
*sec = 24.0*(jday + 0.5 - n);
*hour = (int) floor(*sec);
*sec = 60.0*(*sec - *hour);
*min = (int) floor(*sec);
*sec = 60.0*(*sec - *min);
if (*sec + rounding_tol >= 60.0) {
/* we should round to next minute */
*sec = 0.0;
*min += 1;
if (*min == 60) {
*min = 0;
*hour += 1;
if (*hour == 24) {
*hour = 0;
n++;
}
}
}
/* now find the date */
jul_to_cal(n, y, m, d);
}
/*
* check the existence of given calendar elements
* this includes either number of day in the month
* and calendars pecularities (year 0 and October 1582)
*/
static int check_date(Int_token y, Int_token m, Int_token d, long *jul)
{
int y_expand, y_check, m_check, d_check;
y_expand = expanded_year (y);
if (m.digits > 2 || d.digits > 2) {
/* this should be the year instead of either the month or the day */
return RETURN_FAILURE;
}
*jul = cal_to_jul(y_expand, m.value, d.value);
jul_to_cal(*jul, &y_check, &m_check, &d_check);
if (y_expand != y_check || m.value != m_check || d.value != d_check) {
return RETURN_FAILURE;
} else {
return RETURN_SUCCESS;
}
}
/*
* convert julian day to calendar and hourly elements
*/
void jul_to_cal_and_time(double jday, int rounding,
int *y, int *m, int *d,
int *hour, int *min, int *sec)
{
long n;
double tmp;
/* compensate for the reference date */
jday += get_ref_date();
/* find the time of the day */
n = (long) floor(jday + 0.5);
tmp = 24.0*(jday + 0.5 - n);
*hour = (int) floor(tmp);
tmp = 60.0*(tmp - *hour);
*min = (int) floor(tmp);
tmp = 60.0*(tmp - *min);
*sec = (int) floor(tmp + 0.5);
/* perform some rounding */
if (*sec >= 60 || rounding > ROUND_SECOND) {
/* we should round to at least nearest minute */
if (*sec >= 30) {
(*min)++;
}
*sec = 0;
if (*min == 60 || rounding > ROUND_MINUTE) {
/* we should round to at least nearest hour */
if (*min >= 30) {
(*hour)++;
}
*min = 0;
if (*hour == 24 || rounding > ROUND_HOUR) {
/* we should round to at least nearest day */
if (*hour >= 12) {
n++;
}
*hour = 0;
}
}
}
/* now find the date */
jul_to_cal(n, y, m, d);
/* perform more rounding */
if (rounding == ROUND_MONTH) {
int m2, y2;
if (*m < 12) {
m2 = *m + 1;
y2 = *y;
} else {
m2 = 1;
y2 = *y + 1;
}
if ((cal_to_jul(y2, m2, 1) - n) <= (n - cal_to_jul(*y, *m, 1))) {
*m = m2;
*y = y2;
}
*d = 1;
}
/* introduce the y2k bug for those who want it :) */
*y = reduced_year(*y);
}
