Code:

open(IN, "$inname");

# read rest of input file in 64K junks
while(read(IN, $buffer, 64*1024))
{
$data .= $buffer;
}
close(IN);

my @data = split(//, $data);
my $color = 0;
my $lastcolor = 0;
my $layer = 0;
my $strokes = 0;
my $points = 0;
my $pointcmd = "S";

while($count < $#data) {
my $next = ord($data[$count++]);

if (($next & ~0x07) == 0x80)
{ # pen up/down
if ($next & 0x01)
{
$pointcmd = "S";
print "DEBUG pen down POSITION $count\n" if ($debug);
}
else
{
$pointcmd = "L\nE\n";
$strokes++;
print "DEBUG pen up POSITION $count\n" if ($debug);
}

$color = (($next >> 1) + ($layer * $colorlayers)) & 0x03;
print "DEBUG pen color $color\n" if ($debug);
if ($color != $lastcolor)
{
$lastcolor = $color;
print OUT "%%Color: $color\n";
print OUT ("0 0 0", "1 0 0", "0 1 0", "0 0 1")[$color] . " RGB\n";
}
}
elsif ($next == 0x88) { # time stamp
my $timestamp = ord($data[$count++]);
print "DEBUG TimeStamp $timestamp\n" if ($debug);
print OUT "%%TimeStamp: $timestamp\n" if ($timestamp < 0x7f);
}
elsif ($next == 0x90) { ## end of layer
$layer = ord($data[$count++]);
print "DEBUG End of LAYER $layer\n" if ($debug);
die("Layer # $layer > 127") if ($layer & 0x80);
print OUT "%%EndOfLayer: $layer\n\n";
}
elsif (!($next & ~0x7f)) { ## coordinates
my ($b1, $b2, $b3, $b4) = ($next, ord($data[$count+0]), ord($data[$count+1]), ord($data[$count+2]));
$count += 3;
printf "DEBUG CHECK position $count A %02x %02x %02x %02x\n", $b1, $b2, $b3, $b4 if ($debug);
# die("MSB set in coordinate bytes") if (($b1 | $$b2 | $b3 | $b4) & ~0x7f);

my $x = $b1 + ($b2 << 7);
my $y = $b3 + ($b4 << 7);
print "DEBUG $count: x = $x / y = $y\n" if ($debug);
print OUT "$x $y " . $pointcmd . "\n";
$points++;

$pointcmd = "L";
} else {
die("unknown byte " . sprintf("0x%02x", $next) . " at position $count");
}
}