incr2.c

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/*
 * Copyright (C) 1995.  Bill Brown <brown@gis.uiuc.edu> & Michael Shapiro
 *
 * This program is free software under the GPL (>=v2)
 * Read the file GPL.TXT coming with GRASS for details.
 */
#include <grass/datetime.h>


int datetime_is_valid_increment(const DateTime * src, const DateTime * incr)
{
    return datetime_check_increment(src, incr) == 0;
}



int datetime_check_increment(const DateTime * src, const DateTime * incr)
{
    if (!datetime_is_valid_type(src))
        return 1;
    if (!datetime_is_valid_type(incr))
        return 2;

    if (!datetime_is_relative(incr))
        return datetime_error(-1, "datetime increment mode not relative");
    if (incr->to > src->to)
        return datetime_error(-2, "datetime increment too precise");

    if (datetime_in_interval_year_month(src->to) &&
        !datetime_in_interval_year_month(incr->to))
        return datetime_error(-3, "illegal datetime increment interval");

    if (datetime_in_interval_day_second(src->to) &&
        !datetime_in_interval_day_second(incr->to))
        return datetime_error(-4, "illegal datetime increment interval");

    return 0;
}