Function normalize_holidays_list

numpy/core/src/multiarray/datetime_busdaycal.c:223–262

* Sorts the array of dates provided in place and removes * NaT, duplicates and any date which is already excluded on account * of the weekmask. * * Returns the number of dates left after removing weekmask-excluded * dates. */

 * dates.
 */
NPY_NO_EXPORT void
normalize_holidays_list(npy_holidayslist *holidays, npy_bool *weekmask)
{
    npy_datetime *dates = holidays->begin;
    npy_intp count = holidays->end - dates;

    npy_datetime lastdate = NPY_DATETIME_NAT;
    npy_intp trimcount, i;
    int day_of_week;

    /* Sort the dates */
    qsort(dates, count, sizeof(npy_datetime), &qsort_datetime_compare);

    /* Sweep through the array, eliminating unnecessary values */
    trimcount = 0;
    for (i = 0; i < count; ++i) {
        npy_datetime date = dates[i];

        /* Skip any NaT or duplicate */
        if (date != NPY_DATETIME_NAT && date != lastdate) {
            /* Get the day of the week (1970-01-05 is Monday) */
            day_of_week = (int)((date - 4) % 7);
            if (day_of_week < 0) {
                day_of_week += 7;
            }

            /*
             * If the holiday falls on a possible business day,
             * then keep it.
             */
            if (weekmask[day_of_week] == 1) {
                dates[trimcount++] = date;
                lastdate = date;
            }
        }
    }

    /* Adjust the end of the holidays array */
    holidays->end = dates + trimcount;
}

/*
 * Converts a Python input into a non-normalized list of holidays.