ugrep: random crash and hang in option --zmax>1 when nested jar has a decompression error

Given the following folder structure, ugrep may segmentation fault or deadlock when using with -z and -r arg.

  --root folder (pwd)
    |-- a.jar
           |-- b.jar （within a.jar） 
    |-- b.jar

when decompress the jar file, following warning log indicated there are potential rc:

ugrep: warning: cannot decompress b.jar: a zlib decompression error was detected in the zip compressed data ugrep: warning: cannot decompress b.jar: EOF detected in the zip compressed data