Function rig_raw2val

src/cal.c:61–122

* \brief Convert raw data to a calibrated integer value, according to a * calibration table. * * \param rawval Input value. * \param cal Calibration table, * * cal_table_t is a data type suited to hold linear calibration. * * cal_table_t.size is the number of plots cal_table_t.table contains. * * If a value is below or equal to cal_table_t.table[0].raw, * rig_raw2val() will return cal_t

 * \return Calibrated integer value.
 */
float HAMLIB_API rig_raw2val(int rawval, const cal_table_t *cal)
{
#ifdef WANT_CHEAP_WNO_FP
    int interpolation;
#else
    float interpolation;
#endif
    int i;

    /* ASSERT(cal != NULL) */
    /* ASSERT(cal->size <= HAMLIB_MAX_CAL_LENGTH) */

    rig_debug(RIG_DEBUG_VERBOSE, "%s called\n", __func__);

    if (cal->size == 0)
    {
        return rawval;
    }

    for (i = 0; i < cal->size; i++)
    {
        if (rawval < cal->table[i].raw)
        {
            break;
        }
    }

    if (rawval == cal->table[i - 1].raw)
    {
        return cal->table[i - 1].val;
    }

    if (i == 0)
    {
        return cal->table[0].val;
    }

    if (i >= cal->size)
    {
        return cal->table[i - 1].val;
    }

    /* catch divide by 0 error */
    if (cal->table[i].raw == cal->table[i - 1].raw)
    {
        return cal->table[i].val;
    }

#ifdef WANT_CHEAP_WNO_FP
    /* cheap, less accurate, but no fp needed */
    interpolation = ((cal->table[i].raw - rawval)
                     * (cal->table[i].val - cal->table[i - 1].val))
                    / (cal->table[i].raw - cal->table[i - 1].raw);

    return cal->table[i].val - interpolation;
#else
    interpolation = ((cal->table[i].raw - rawval)
                     * (float)(cal->table[i].val - cal->table[i - 1].val))