Re: [Dvbstreamer-user] possible bug: MJD conversion

[Adam C. <ad...@dv...>]

On Thu, 2011-02-24 at 14:30 +0100, Alex Metelka wrote:
> Hi,
> 
> MJD conversion routine dvbpsi_DecodeMJDUTC() in src/dvbpsi/datetime.c seems to 
> be buggy. Some dates are converted incorrectly, eg. MJD 0xD945 corresponding 
> to Mar-01-2011 is resolved as Mar-04-2011 (tested on debian squeeze/amd64).
> 
> I didn't try to debug current routine code with floats, as much simpler 
> replacement is possible:
> 
> 
> void dvbpsi_DecodeMJDUTC(uint8_t *p_mjdutc, struct tm *p_date_time)
> {
>     #define BCD_CHAR_TO_INT(_bcd) (((_bcd >> 4) * 10) + (_bcd & 0x0f))
>     time_t secs;
> 
>     uint16_t i_mjd = (((uint16_t)p_mjdutc[0] << 8) | (uint16_t)(p_mjdutc[1] & 
> 0xff));
> 
>     secs = (time_t)(((uint32_t)i_mjd-40587)*86400);
> 
>     secs += (BCD_CHAR_TO_INT(p_mjdutc[2]))*3600+
>                 (BCD_CHAR_TO_INT(p_mjdutc[3]))*60+
>                 (BCD_CHAR_TO_INT(p_mjdutc[4]));
> 
>     memcpy(p_date_time, gmtime(&secs), sizeof(struct tm));
> }
> 
> 
> Regards,
> 
> Alex

Thanks for bug report, I did manage to debug the float routines (which
come from DVB spec) I'd missed a int conversion. Having worked out what
you are doing I've committed a modified patch.

Thanks again,

Adam