HI Ticker, I think new Garmin maps have a lot more bits set, but GPXSee doesn't even read the basic 8 bits, so I can leave the code as is for now.
Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-boun...@lists.mkgmap.org.uk> im Auftrag von Ticker Berkin <rwb-mkg...@jagit.co.uk> Gesendet: Samstag, 12. Februar 2022 17:54 An: Development list for mkgmap Betreff: Re: [mkgmap-dev] Patch: use all 4 bytes of POIGlobalFlags in LBL Header Hi Gerd An interpretation of the comment is that POIGlobalFlags data is 16 bits, and, if bit 9 is set, the next byte is the number of extra word of POI information immediately following. The data then continues with 2 bytes unknown, POITypeIndex Position/Size/ItemSize... As mkgmap always writes zero to the byte that would hold bit 9, the extra byte/words won't happen and so the patch won't change any behaviour. However, it seems more useful to change the code as the comment suggests, with a get2u/put2u of flags and get2u/put2u zero/ignore, adjust the comment and, on read, assert bit 9 not set. It does seem very unlikely there would be a variable length structure in a header! Ticker On Sat, 2022-02-12 at 15:21 +0000, Gerd Petermann wrote: > Hi Ticker, > > I don't understand. The number of bytes doesn't change, the > patch just places more information in the flags field instead of > ignoring them. > I am not aware of any code in mkgmap that reads or fills those > bits,yet. > > Gerd > > ________________________________________ > Von: mkgmap-dev <mkgmap-dev-boun...@lists.mkgmap.org.uk> im Auftrag > von Ticker Berkin <rwb-mkg...@jagit.co.uk> > Gesendet: Samstag, 12. Februar 2022 15:19 > An: Development list for mkgmap > Betreff: Re: [mkgmap-dev] Patch: use all 4 bytes of POIGlobalFlags in > LBL Header > > Hi Gerd > > Reading it more carefully, probably the basic flag set is 16 bits, > with > 0x0100 indicating more bytes to read/write > > Ticker > > > On Sat, 2022-02-12 at 12:36 +0000, Ticker Berkin wrote: > > Hi Gerd > > > > Although the comment might have inaccuracies and be ambiguous, it > > contains useful information about how the extra flags for POI might > > be > > represented, which could be different from just reading 4 bytes. > > > > One way of interpret it is if (first byte & 0x80), then read/write > > extra bytes; the 3 zero/unknown bytes not being part of this flag > > set. > > > > Ticker > > > > > > On Fri, 2022-02-11 at 15:33 +0000, Gerd Petermann wrote: > > > And now with the patch ... > > > > > > Gerd > > > > > > ________________________________________ > > > Von: Gerd Petermann > > > Gesendet: Freitag, 11. Februar 2022 16:32 > > > An: mkgmap-dev@lists.mkgmap.org.uk > > > Betreff: Patch: use all 4 bytes of POIGlobalFlags in LBL Header > > > > > > Hi devs, > > > > > > attached patch simplifies the code, but should not change > > > anything > > > in > > > the output of mkgmap. > > > > > > GPXSee contains code to evaluate some of the bits which were > > > ignored > > > so far. > > > > > > Do you see any problems? > > > > > > Gerd > > > _______________________________________________ > > > mkgmap-dev mailing list > > > mkgmap-dev@lists.mkgmap.org.uk > > > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > > > > _______________________________________________ > > mkgmap-dev mailing list > > mkgmap-dev@lists.mkgmap.org.uk > > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev@lists.mkgmap.org.uk > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev@lists.mkgmap.org.uk > https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev