Ignore excess bytes in pysrr input source

[Former user]

Often when I am creating rars with a srr & pysrr it will complain that the file is too big and not continue. 99% of the time this is because the file has an extra byte or 10 of garbage data added at the end. To fix the file I use GNU coreutils truncate it manually and try again.

I would like a switch that will tell pysrr to only care about the bytes specifed in the srr and ignore any extra data at the end.