Mirror of forum.nim-lang.org

4376 :: [OT]if we also know basic algorithms theory, how can we get the details?

• oyster (orginal) [2018-11-12T07:31:54+01:00] view original

  if it is too off-topic, please delete it, thanks

  I have old applications from whose name I think they uses LZW compression. However I checked some LZW libs(C/python/nim) but none of them yields the same output files. I think the DOS app uses different code symbols during compression. So how can we program to fetch the proper compression algorithm? Thanks

  the app and data files are https://drive.google.com/open?id=1EpPs7oAUleS2xjCSqDX0rfuHkWZ0A3yU

  Lzw15.exe a gd_def.txt gd_def.tx_' compress a text file `Lzw15.exe e gd_def.tx_ gd_def.txt decompress a compressed file

---

• enthus1ast (orginal) [2018-11-13T12:28:59+01:00] view original

  the LZW algorithm does produce integer but writeing integer instead of byte would bloat up the output file, so one way to still get resonable output size is to write for example 12bit numbers to the output file. Since this is so, LZW is normally not used directly but it is wrapped in some "output frames" afaik these are application specific. I dont know exactly but it could be that there are some widely used LZW frames. Maybe check if you could open the file with 7zip, maybe it tells you what output frames where used.

---