#! /usr/bin/perl

# ptreader.pl - Papertape decoder for the Simh Data General Nova/Eclipse Simulator
#                   The linux file PTP.OUT is produced by the RDOS BPUNCH command
#                   PTP.OUT is a binary file that has a lot of leading and trailing nulls
#                   The nulls are stripped off and the remainder is copied to the output
#                   file PTP.TXT. Line endings are converted.
#
#                ptreader provides a way to copy text files from
#                   the simulated RDOS filesystem to the linux filesystem
#
#                RDOS -> PTP.OUT -> ptreader.pl -> PTP.TXT
#
# Created by:    James M. Lynes jr.
# Created on:    January 29,2024
# Last Modified: 01/29/2024 - Initial version
#                01/30/2024 - Additional comments, fix line ending(0x0A)
#
# Usage:         On RDOS: BPUNCH filename
#                    Creates the (binary formatted) linux file: PTP.OUT
#
#                On linux: ./ptreader.pl
#                    Reads PTP.OUT and creates the reformated linux text file PTP.TXT
#
# Note:          Use ptwriter.pl to format a linux text file to be read by RDOS

use strict;
use warnings;

open(my $in, '<:raw', "PTP.OUT") or die;
open(my $out, '>', "PTP.TXT") or die;

my $content;
my $length;
my $maxlength = 4000;
my @inbytes;
my @outbytes;

$length = read($in, $content, $maxlength);       # Read the binary file
print "Length: $length\n";                       # Show total bytes read

@inbytes = unpack("C*", $content);               # Unpack bytes into an array

foreach(@inbytes) {                              # Delete null bytes
    next if($_ == 0);
    push(@outbytes, $_);
}

foreach(@outbytes){printf ("0x%02X ", $_)};      # Show a hex dump of array
print "\n";

foreach(@outbytes) {                              # Show the text read 
    my $code = chr($_);
    
    if($_ == 0x0D) {
        $code = chr(0x0A);                        # Fix linux line ending
    }

    print "$code";
    print $out $code;                            # Copy text to output file
}

close $in;
close $out;