#!/usr/bin/perl
# 
# Copyright © 2015-2020 by Vincent Slyngstad
# 
# Permission is hereby granted, free of charge, to any person obtaining
# a copy of this software and associated documentation files (the
# "Software"), to deal in the Software without restriction, including
# without limitation the rights to use, copy, modify, merge, publish,
# distribute, sublicense, and/or sell copies of the Software, and to
# permit persons to whom the Software is furnished to do so, subject to
# the following conditions:
# 
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
# 
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS LISTED ABOVE BE LIABLE
# FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
# CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
# 
# Except as contained in this notice, the names of the authors above
# shall not be used in advertising or otherwise to promote the sale, use
# or other dealings in this Software without prior written authorization
# from those authors.

# Dump the media in octal and sixbit.

# Pick a block size (in words!)
$bsize = 128;
$upack = "S$bsize";

#
# The most common sixbit encoding:
@sixbit = (
  "\032","A", "B", "C", "D", "E", "F", "G",  # 00x
  "H",   "I", "J", "K", "L", "M", "N", "O",  # 01x
  "P",   "Q", "R", "S", "T", "U", "V", "W",  # 02x
  "X",   "Y", "Z", "[", "\\","]", "^", "\r", # 03x
  " ",   "!", '"', "\n","\$","%", "?", "\t", # 04x
  "(",   ")", "*", "+", ",", "-", ".", "/",  # 05x
  "0",   "1", "2", "3", "4", "5", "6", "7",  # 06x
  "8",   "9", ":", ";", "<", "=", ">", "?",  # 07x
);
#
# The LAP6 sixbit encoding:
@sixbit = (
  "0",   "1", "2", "3", "4", "5", "6", "7",   # 00x
# "8",   "9", "\n","?", " ", "I", ".", "-",   # 01x
  "8",   "9", "\.","?", " ", "I", ".", "-",   # 01x
  "+",   "\\","#", " ", "A", "B", "C", "D",   # 02x
  "E",   "F", "G", "H", "I", "J", "K", "L",   # 03x
  "M",   "N", "O", "P", "Q", "R", "S", "T",   # 04x
# "U",   "V", "W", "X", "Y", "Z", "\n","/",   # 05x
  "U",   "V", "W", "X", "Y", "Z", "\.","/",   # 05x
# "\033","=", "U", ",", ".", "\$","[", "_",   # 06x
  "\.",  "=", "U", ",", ".", "\$","[", "_",   # 06x
# '"',   '"', "<", ">", "]", "*", ":", "\032",# 07x
  '"',   '"', "<", ">", "]", "*", ":", "\.",  # 07x
);

# Open the file
open(INPUT, $ARGV[0]) || die "$ARGV[0]: $!";
binmode(INPUT);

#
# Read each block and print it.
for ($block = 0; ; $block++) {
    seek(INPUT, $block*2*$bsize, 0) || die "$ARGV[0] file seek: $!";
#   read(INPUT, $buf, 2*$bsize) || die "$ARGV[0] file read: $!";
    read(INPUT, $buf, 2*$bsize) || last;
    @buf = unpack($upack, $buf);
    $sixbit = "";
    for ($offset = 0; $offset < $bsize; $offset++) {
        if ($offset%8 == 0) {
            printf "%s\r\n%04o %03o)", $sixbit, $block, $offset;
            $sixbit = "";
        }
        printf "%04o ", $buf[$offset];
   	@c = ($buf[$offset]>>6, $buf[$offset]&077);
    	grep($_ = $sixbit[$_], @c);
    	$sixbit .= join('', @c);
    }
    $sixbit =~ s/[\000-\037]/./g; # Force printable
    printf "%s\r\n", $sixbit;
}