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-bounces@lists.mkgmap.org.uk> im Auftrag von Ticker Berkin <rwb-mkgmap@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?
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