#!/usr/bin/perl
# Convert hexdump -C like output back to binary.  Supports * lines, which
# xxd -r does not (this is the reason for this script).  Assumes good input.

use strict;
use warnings;

my ($off, $line, $asterisk);

while (<>) {
    if (/^([[:xdigit:]]{2,}0)\s+((?:[[:xdigit:]]{2}\s+){1,16})/) {
        if (defined($asterisk)) {
            my $nlines = (hex($1) - hex($off)) / 16 - 1;
            print map { chr hex } split /\s+/, $line x $nlines;
            undef $asterisk;
        }
        print map { chr hex } split /\s+/, $2;
        $off = $1, $line = $2;
    } elsif (/^\*/) {
        $asterisk = 1;
    } else {
        last;
    }
}