Function _xmlSchemaDateAdd

ThirdParty/libxml2/vtklibxml2/xmlschemastypes.c:3912–4053

* _xmlSchemaDateAdd: * @dt: an #xmlSchemaValPtr * @dur: an #xmlSchemaValPtr of type #XS_DURATION * * Compute a new date/time from @dt and @dur. This function assumes @dt * is either #XML_SCHEMAS_DATETIME, #XML_SCHEMAS_DATE, #XML_SCHEMAS_GYEARMONTH, * or #XML_SCHEMAS_GYEAR. The returned #xmlSchemaVal is the same type as * @dt. The calling program is responsible for freeing the returned value

 * Returns a pointer to a new #xmlSchemaVal or NULL if error.
 */
static xmlSchemaValPtr
_xmlSchemaDateAdd (xmlSchemaValPtr dt, xmlSchemaValPtr dur)
{
    xmlSchemaValPtr ret, tmp;
    long carry, tempdays, temp;
    xmlSchemaValDatePtr r, d;
    xmlSchemaValDurationPtr u;

    if ((dt == NULL) || (dur == NULL))
        return NULL;

    ret = xmlSchemaNewValue(dt->type);
    if (ret == NULL)
        return NULL;

    /* make a copy so we don't alter the original value */
    tmp = xmlSchemaDupVal(dt);
    if (tmp == NULL) {
        xmlSchemaFreeValue(ret);
        return NULL;
    }

    r = &(ret->value.date);
    d = &(tmp->value.date);
    u = &(dur->value.dur);

    /* normalization */
    if (d->mon == 0)
        d->mon = 1;

    /* normalize for time zone offset */
    u->sec -= (d->tzo * 60);
    d->tzo = 0;

    /* normalization */
    if (d->day == 0)
        d->day = 1;

    /* month */
    carry  = d->mon + u->mon;
    r->mon = (unsigned int) MODULO_RANGE(carry, 1, 13);
    carry  = (long) FQUOTIENT_RANGE(carry, 1, 13);

    /* year (may be modified later) */
    r->year = d->year + carry;
    if (r->year == 0) {
        if (d->year > 0)
            r->year--;
        else
            r->year++;
    }

    /* time zone */
    r->tzo     = d->tzo;
    r->tz_flag = d->tz_flag;

    /* seconds */
    r->sec = d->sec + u->sec;