4 ms·

Fails if fed its own output again if that was compressed before, and now goes in the uncompressed case.

• willvarfar 5y ago
  Compress file A generated compressed file B. Compress file B fails to make it shorter, so the generated file C is actually identical to B. We’ve just compressed twice. Uncompressing twice generates A again.
  • jonas21 5y ago
    The problem is if you start with B. Then you compress it to get C. Since B == C, when you uncompress C, you get A, which is not what you started with.
  • detaro 5y ago
    I'm talking about compressing/decompressing that once. Then input != output, thus it's not a working compression formally.