This works for your sample data but probably not your real data:

my $s = pack 'C5', qw[1 7 11 3 100];

say "$_: ", unpack '%C5', $s & tr/?+-/\0\xff/r for qw[
  --+-+
  ---++
  ?????
  -???+
];
[download]

Output:

--+-+: 122
---++: 122
?????: 0
-???+: 101
[download]