[Gpsbabel-code] Bug in nmea.c

[Robert L. <rob...@gm...>]

Thanx for the good description.  How about char* orig_tbuf = buf at the top
and changing the xfree to just  unconditionally free orig_tbuf?

Also, please include a test case for your Blackview thing in
testold/nmea.test and a few sentences that adds it to the doc in
xmldoc/formats/nmea.xml

This function  is the poster child why I want to get out of the
malloc/cstring business...
On Wed Mar 05 2014 at 6:39:54 AM, Din <sup...@gm...> wrote:

> Hello!
>
> Think I've found a bug in nmea.c
> function:  nmea_parse_one_line(char* ibuf)
>
> ....
> if (0 == strncmp(tbuf, "---,", 4)) {
>
>
>       tbuf += 4;
> }
> tbuf now doesn't point to the correctly allocated memory
> and is not equal to ibuf
>
> if the following condition goes false
>    if (strstr(tbuf, ",,")) {  /// -> false
>      tbuf = gstrsub(tbuf, ",,", ",0,");
>    }
>
> we get free memory error
>    if (tbuf != ibuf) {
>      ...........
>      xfree(tbuf);
>    }
>
> So...  the following patch works correct
> and also covers BlackView gps (nmea) data format
> which includes additional info at the beginning
> ex:
> [1388140897124]$GPGGA,064142.999,5547.7374,N,03732.6450,E,
> 1,09,1.1,163.9,M,13.7,M,,0000*57
>
>
> @@ -909,6 +909,8 @@ nmea_parse_one_line(char* ibuf)
>     char* ck;
>     int ckval, ckcmp;
>     char* tbuf = lrtrim(ibuf);
> +  int bNeedFree = 0;
> +  char *pPass = NULL;
>
>     /*
>      * GISTEQ PhotoTracker (stupidly) puts a bogus field in front
> @@ -918,10 +920,12 @@ nmea_parse_one_line(char* ibuf)
>       tbuf += 4;
>     }
>
> -  if (*tbuf != '$') {
> -    return;
> +  if ( NULL == (pPass = strchr(tbuf, '$')) ) {
> +      return;
>     }
>
> +  tbuf = pPass;
> +
>     ck = strrchr(tbuf, '*');
>     if (ck != NULL) {
>       *ck = '\0';
> @@ -957,6 +961,7 @@ nmea_parse_one_line(char* ibuf)
>     */
>     if (strstr(tbuf, ",,")) {
>       tbuf = gstrsub(tbuf, ",,", ",0,");
> +    bNeedFree = 1;
>     }
>
>     if (0 == strncmp(tbuf, "$GPWPL,", 7)) {
> @@ -989,7 +994,7 @@ nmea_parse_one_line(char* ibuf)
>       amod_waypoint = 1;
>     }
>
> -  if (tbuf != ibuf) {
> +  if (0 != bNeedFree) {
>       /* clear up the dynamic buffer we used because substition was
> required */
>       xfree(tbuf);
>     }
>
> Best Regards,
> Kiselev Stanislav
> sup...@gm...
> aka 2:5020/2140.486
>
>
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