#!/usr/bin/perl
# 
# Copyright © 2015-2025 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.

#
# Given a file in .asc format (ascii encoded 3 characters per double-word
# (TSS bit ordering), each word then recorded as 16 bits), output the text
# as ASCII, stripping mark parity, if set.
foreach $f (@ARGV) {
  open(INPUT, $f) || die "$f: $!";
  binmode(INPUT);
  while (read(INPUT, $buf, 4)) {
    # Unpack the double-word.
    ($c1, $c3) = unpack("SS", $buf);
    $c3 += $c1 << 12;
    # Extrace $c1 and $c2.
    $c1 = ($c3 >> 16);
    $c2 = ($c3 >>  8);
    print pack("CCC", $c1 & 0177, $c2 & 0177, $c3 & 0177);
  }
}