#!/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.

# Unpack every 3 TSS8 bytes into 2 words.  Output the words as a
# rudimentary file in .bin format.  Each input file is presumed to
# be a program in .sav format, designed to load starting at location 0.

# Output leader/trailer.
sub leader {
  for ($i = 0; $i < 120; $i++) {
    print OUTPUT pack("C", 0200);
  }
}

# Ouput a word and update the checksum.
sub dframe {
  local($word) = @_;
  print OUTPUT pack("CC", $word >> 6, 077 & $word);
  $checksum += $word >> 6;
  $checksum += 077 & $word;
}

foreach $f (@ARGV) {
  open(INPUT, $f) || die "$f: $!";
  binmode(INPUT);
  $of = $f; $of =~ s/[.]view$/.bin/;
  die "$f: Expected .view" if $f eq $of;
  open(OUTPUT, ">$of") || die "$of: $!";
  binmode(OUTPUT);
  &leader;
# print OUTPUT pack("CC", 0100, 0);
# $checksum = 0100;
  $word = $loc = undef;
  while (<INPUT>) {
    while ($_ ne "") {
      if (s/^([0-7])//) {
        $word = 0 unless defined $word;
        $word = ($word << 3) + $1;
      } elsif (s/^FIELD\s+([0-7])//i) {
        print OUTPUT pack("C", 0300 + (($1&07) << 3));
      } elsif (s/^[\/]//) {
        die "Use ')' for location setting\n" unless $loc == $word;
        $word = undef; # Don't store if blank follows
      } elsif (s/^[X]//i) {
        $word = -1; # Will increment address, but not store
      } elsif (s/^[\)]//) {
        die "$f: no location for location setting\n" unless defined $word;
        $loc = $word;
        &dframe(010000+$loc);
        $locn = $loc;
        $word = undef;
      } elsif (s/^[\s\r\n]//) {
        next unless defined $word;
        unless ($word < 0) {
          &dframe(010000+$loc) unless $loc == $locn;
          &dframe($word) unless $word < 0;
          $locn = $loc + 1;
        }
        $word = undef;
        $loc = 07777 & ($loc+1);
      } else {
        die "Illegal character: $_";
      }
    }
  }
  &dframe(07777 & $checksum);
  &leader;
}