From: nowhere@never.at   
      
   I answered Terje Mathisen:   
   ...   
   >>>> My first ascii executable used both POP BX and Base91. :-)   
   >>> was it much shorter then ?   
      
   >> It didn't need the Base64 decoder, but handling 16-bytes to 13 isn't   
   >> free either. This was more than 20 years ago so I don't remember the   
   >> details, like what I did if the input wasn't a multiple of 13 bytes long?   
      
   [C..] you now my inabilty to read this.   
      
   I checked on how 16:13 encoding could work, but I sure missed the trick   
   and I would need 5 bits more (2*13 hints for 13 byte).   
      
   a 16* 7-bit string to 14* 8-bit conversion will not work (no 00..20),   
   even a 16:14 variant would gain a bit more.   
      
   my yet shortest will be a 9:7 encoding.   
      
   ie: (first two bytes contain 14 modify hints)   
   a set bit 0 will sub 0x30 of 3rd byte, (bit 1..6 work on 4th..9th)   
   a set bit 8 will sub 0x7e of 3rd byte, so if both are set then sub both.   
      
   and it can end early, so multiple of 7 isn't required. it gaines 5%   
   over base64. Now this is already one byte less in our Hello World :)   
   __   
   wolfgang   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)