#!/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.

#
# Convert ".rke" format to ".dsk" format.
#

foreach $f (@ARGV) {
  open(INPUT, $f) || die "$f: $!";
  binmode(INPUT);

  $o = $f;
  $o =~ s/.rke$//;
  $o .= ".dsk";
  open(OUTPUT, ">$o") || die "$o: $!";
  binmode(OUTPUT);

  #
  # Read in the file header.
  read(INPUT, $buf, 0x16D) || die "$f header: $!";
  ($magic, $version, $name, $desc, $date, $cont, $br, $nc, $ns, $nh, $us)
    = unpack("a10a4a11a200a20a100NNNNN", $buf);
#warn "$magic, $version, $name, $desc, $date, $cont, $br, $nc, $ns, $nh, $us\n";
  die "$f: not rke format " unless $magic == "\x89RK05\r\n\x1A";
  die "$f: cyls != 203" unless $nc == 203;
  die "$f: spt != 16" unless $ns == 16;
  die "$f: heads != 2" unless $nh == 2;
  # At this point it looks like PDP-8 RK05 media.

  #
  # Now, iterate over the data sectors, emitting only the
  # 12 bit data words, each as 16 bits in SIMH .dsk format.
  #
  while (read(INPUT, $buf, 4) == 4) {
    ($tts, $dbits) = unpack("SS", $buf);
    #
    # Read a data bit blob of length $dbits.
    #
    $words = $dbits >> 4;
    $words++ if $dbits % 16; # RKE pads to 16 bit multiple
#warn "reading $words words\n";
    read(INPUT, $buf, 2*$words) || die "$f data read: $!";
    @buf = unpack("C*", $buf);
    #
    # Discard 16 bits for header (cyl<<5)
    #
    shift @buf; shift @buf;
    die "$#buf" unless @buf > 384;
    for ($i = 0; $i < 128; $i++) { # 128 word pairs per sector
      # Unpack a doubleword (3 bytes)
      $b1 = shift @buf;
      $b2 = shift @buf;
      $b3 = shift @buf;
      $w1 = ($b3 << 16) + ($b2 << 8) + $b1;
      $w2 = $w1 >> 12;
      $w1 = $w1 & 07777;
      printf OUTPUT pack("SS", $w1, $w2);
    }
  }
}