Hi Gerd I guessed that it was the \0 that cut the file off.
You mean something like answer 5 here: https://stackoverflow.com/questions/759707/efficient-way-of-storing-huffman-tree I looked at this earlier trying to work out if it was relevant but didn't make it fit - I should have tried harder. I still haven't spotted anything to determine the length of the 2 /3 byte in before and in the struct for {length} Ticker On Thu, 2021-12-23 at 01:17 +0000, Gerd Petermann wrote: > Hi Ticker, > > sorry, just noticed that something went wrong with copy&paste because > of the \0 character. > Anyway, I think I understand the meaning of the part with the prefixes. > I assume that Garmin reads the first 5 bits and uses this value as an > index into a table > which directly follows the first array. This 2nd table is a 32x2 lookup > table, where the 2nd byte gives the value > and the first byte some kind of status info which is used to position > the bit reader. > This would explain the repeating characters. Something like this: > > --------- MDR 16 (decompression codebook Huffman tree) ---------------- > --------- > 000002b6 | 000000 | 4a | ??? _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev