[mkgmap-dev] Format6Encoder/Decoder

Wed Dec 1 10:23:00 GMT 2021

Hi Gerd

I'll investigate index problems and Format6 a bit next week to see what
MapInstall does and if there is a correct way to represent the strings
that Mdr places, or to say what encoding they are in.

Fixing, extending and simplifying the Format6Decoder is worthwhile,
along with the CodeFunctionsTest changes, so I've made another patch
that rewords the OPTIONS and stops the Format6Encoder doing lower-case,
but leaves the mechanisms there. It will encode the extra chars "`{|}".

Ticker

On Tue, 2021-11-30 at 15:15 +0000, Gerd Petermann wrote:
> Hi Ticker,
> 
> with r4821 I can still reproduce search problems with --code-page=0
> when road names start with symbols ("@Road" or "#Street") (in
> MapSource). I guess the shift character is the problem.
> With your patch it is much more likely that the first 4 characters
> contain such a shift byte.
> Or maybe the sort order for these is wrong?
> 
> Did not try to find a solution for this and I have no Garmin map that
> uses 6bit encoding. Possibly we just can skip writing mdr17 as we do
> with unicode.
> 
> A few things are really confusing reg. the --code-page and --charset
> option.
> 1) if you specify e.g. --code-page=cp1252 or --code-page=ms932 mkgmap
> will silently change that to cp0. See getCodePage() in CommandArgs.
> 2) the option --charset is deprecated but still evaluated. Something
> like --charset=cp1252 --code-page=1254 probably causes trouble.
> 
> Gerd
> 
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> von Gerd Petermann <gpetermann_muenchen at hotmail.com>
> Gesendet: Dienstag, 30. November 2021 14:21
> An: Development list for mkgmap
> Betreff: Re: [mkgmap-dev] Format6Encoder/Decoder
> 
> Hi Ticker,
> 
> seems you are partly right. I created a map with cp0 and --lower-case
> and the search for road names starting with "augs" doesn't return
> Augsburger Strasse on the device.
> Without -lower-case this works as expected. I've reverted r4820 for
> now, but maybe the combination never works well. Needs more testing.
> 
> Gerd
> 
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> von Ticker Berkin <rwb-mkgmap at jagit.co.uk>
> Gesendet: Dienstag, 30. November 2021 12:15
> An: Development list for mkgmap
> Betreff: Re: [mkgmap-dev] Format6Encoder/Decoder
> 
> Hi Gerd
> 
> Building a map with --code-page=0 --index --gmapsupp --gmapi
> (exactly same behaviour without --code-page=0)
> 
> Then, using raw mode editor to look at various components.
> 
> The LBL section of tiles, gmapsupp.img and gmapi looks encoded - I
> can't find any recognisable strings.
> 
> However, the gmapsupp contains the 4-char prefixes (as per Mdr17)
> with
> standard ascii encoding, the gmapi 00OSMMAP.MDR contains full names
> of
> everything, again as ascii (probably Mdr15) and .typ file is also
> ascii.
> 
> I can't find any ascii in the overview map (except the expected
> subfile
> names and copyright), but my test area might not have anything named
> at
> this level.
> 
> It is possible that MDR does this intentionally; avoiding the
> "compressed" format that Mdr15.java / MdrDisplay mentions. This
> compressed format might simply be Format6
> 
> Ticker
> 
> On Tue, 2021-11-30 at 10:20 +0000, Gerd Petermann wrote:
> > Hi Ticker,
> > 
> > I also don't like that we still use e.g.  Charset.forName("ascii")
> > instead of StandardCharsets.US_ASCII, esp. because "ascii" is also
> > used as name for our own resource files.
> > 
> > In what situation do you see wrong encoding of Mdr15/Mdr17?
> > 
> > Gerd
> 
> 
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