On 6/13/22, Askar Safin wrote:
Hi. I installed lzip 1.23-3 to my debian from debian repo. Is it true that default decompression mode (i. e. lzip -d file.lz) verifies archive? "man lzip" doesn't say anything about this.
If file.lz was generated by a single compression, then I believe that decompression verifies integrity. The test is simple: the working value for the range coding must be zero.
Also, is it true that compressed file truncation is absolutely always detected? (Multiply bit flips are hard to detect with absolute guarantee, but I think it is quite possible to always detect file truncation.) Is file truncation detected in default mode (lzip -d file.lz)? "man lzip" is silent on this
If the input to decompression is the concatenation of the outputs from two or more single compressions, and if lzip allows and interprets this as representing a compression of the concatenation of the original inputs, then detecting truncation at a point of concatenation requires a check "has all the input been read?" Such a test is easy for a regular file, but problematic for a pipe such as stdin, which can be specified on Linux using the filename "/proc/self/fd/0". --
