[mkgmap-dev] [mkgmap-svn] Commit r4854: - fix possible error when negativ index was written to lookup table

Mon Jan 10 21:53:40 GMT 2022

Hi Gerd

I think I got table1 / table2 names the wrong way round. The bit about
"should it need" is probably necessary when all the levels fit into the
prefix table but it isn't full.

I won't look at it again until you want me to.

Ticker

On Mon, 2022-01-10 at 19:16 +0000, Gerd Petermann wrote:
> Hi Ticker,
> 
> table1 size depends on the number of levels with values and the
> existence of the lookup table, empty levels are not stored.
> When there is a lookup table (table2) we must not store the
> corresponding top 5 /6 levels in table1.
> 
> I don't understand the part after "Should it need ..." . It worked in
> my tests but of course I might have missed a special case.
> It's all work in progress. I plan to add unit tests, something like
> "given these frequencies and codepage xyz the result should look like
> ...".
> 
> I plan to recode MdrDisplay now that I undestand almost all data.
> I also want to implement this in MdrCheck during the next days.
> 
> Gerd
> 
> 
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag
> von Ticker Berkin <rwb-mkgmap at jagit.co.uk>
> Gesendet: Montag, 10. Januar 2022 17:49
> An: Development list for mkgmap
> Betreff: Re: [mkgmap-dev] [mkgmap-svn] Commit r4854: - fix possible
> error when negativ index was written to lookup table
> 
> Hi Gerd
> 
> More minor stuff - Still haven't understood the mincode parts
> 
> mdr/Mdr16.java:
> 
> loopupBits/lookupBits is very confusing.
> Can you have lookupBits for table2 size and something else for table1
> size
> 
> If maxDepth < initial size (5 or 6), can't you just set table1 size
> to
> maxDepth and set table2 size to 0. Or did you find this combination
> didn't work.
> 
> Should it need:
>         while (pos >= 0) {
>                 tab2[pos * 2] = 0;
>                 tab2[pos * 2 + 1] = (byte) lastIndex;
>                 pos--;
>         }
> Won't the data have been exhausted, with v0 being the first index of
> table1 (0) and v2 correct
> 
> MdrDisplay:
> would be clearer to spot/remember the bottom bit flag in table2, and
> > > 1 the data in both cases, then present the char data as
> > > numBits/char
> and the non-char data as minLev/maxLev
> 
> Ticker
> 
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