#!/usr/bin/perl -w
=head1 README

wqvlinktoppm - convert Palm WQVLink database backup to ppm images

This is a quick hack to parse out Casio Wrist Camera images from the Palm's
WQVLinkDB.pdb backup file.

To use (unashamedly *nix-specific instructions):

    echo "Backing up Palm"

    mkdir -p ~/pilot/backup; pilot-xfer -s ~/pilot/backup

    echo "Finding images"

    wqvlinktoppm ~/pilot/backup/WQVLinkDB.pdb

    echo "viewing images"

    ee wqv_image_*.ppm

Acknowledgements:

    - http://www.mgroeber.de/misc/wqvprot.htm - details of image bytes and
      header

    - http://www.casio.com/support/index.cfm?page=/support/software/wrist_camera.html
      WQVLink as Palm PRC

To do:

    - make it friendlier.  I'm not going to, this is a quick hack ;)

    - read metadata.  Again, not bothered

Author: jm /at/ jmason.org  -- License: GPL
Last modified Sep 26 2001 jm 

=cut

# make a quick CLUT (colour lookup table) for the WQV palette
my @clut = ( );
for my $gray (0..15) {
  $clut[$gray] = 0x100 - ($gray * 16);
}
$clut[0] = 0xff;

# read the header
open (STDIN, "<$ARGV[0]") or
		die "usage: wqvlinktoppm WQVLinkDB.pdb\n";

read STDIN, $_, 0x4c;
read STDIN, $_, 0x02;
my $NUM_PICS = unpack ("n1", $_);

# these were determined by inspection.
$SKIP_HEADER_LEN = 0x02 + (8 * $NUM_PICS) + 0x13e;

$PIC_WIDTH_PIXELS = 120;
$PIC_HEIGHT_PIXELS = 120;
# each pixel == 1 nybble
$BYTES_PER_PIC = ($PIC_WIDTH_PIXELS*$PIC_HEIGHT_PIXELS) / 2;

$SKIP_BETWEEN_PICS_LEN = 836;

read STDIN, $_, $SKIP_HEADER_LEN;		# skip header

my $num = 0;
while (!eof STDIN) {
  read STDIN, $_, $BYTES_PER_PIC;
  my @bytes = unpack ("C*", $_);

  my @nybs = ();
  for my $i (0..($BYTES_PER_PIC-1)) {
    my $byte = pop (@bytes);
    push (@nybs, $byte & 0x0f);
    push (@nybs, ($byte & 0xf0) >> 4);
  }

  $num++;
  my $fname = sprintf ("wqv_image_%03d.ppm", $num);
  open (OUT, ">$fname") or die "write to $fname failed";
  print OUT "P3\n120 120\n15\n";

  my $ls = 0;
  for my $x (0..($PIC_WIDTH_PIXELS-1)) {
    for my $y (0..($PIC_HEIGHT_PIXELS-1)) {
      my $col = $clut[pop(@nybs)];
      printf OUT "%03d %03d %03d  ", $col, $col, $col;
      if ($ls++ > 4) {
	print OUT "\n"; $ls = 0;
      }
    }
  }
  print OUT "\n";
  close OUT or die "write to $fname failed";

  print "Created: $fname\n";

  read STDIN, $_, $SKIP_BETWEEN_PICS_LEN;
}