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package Acme::Steganography::Image::Png::RGB;

use vars '@ISA';
@ISA = 'Acme::Steganography::Image::Png';

# Raw data in the low bits of a colour image

sub write_images {
  my $self = shift;
  my $victim = shift;

  my $img;
  if (ref($victim) && $victim->isa('Imager')) {
    $img = $victim;
  } else {
    $img = new Imager;
    $img->open(file=>$victim, type=>'jpeg') or croak($img->errstr);
  }


  $self->x($img->getwidth());
  $self->y($img->getheight());

  my $raw;
  $img->write(data=> \$raw, type => 'raw')
    or croak($img->errstr);

  $self->raw($raw);

  $self->SUPER::write_images;
}
package Acme::Steganography::Image::Png;

sub generate_next_image {
    my ($self) = shift;
    my $datum = $self->generate_header;
    my $offset = $self->offset;
    my $datum_length = $self->datum_length;
    # Fill our blob of data to the correct length
    my $grab = $datum_length - length $datum;
    $datum .= substr ${$self->data()}, $offset, $grab;
    $self->offset($offset + $grab);

    if (length $datum < $datum_length) {
      # Need to pad it. NUL is so uninspiring.
      $datum .= "N" x ($datum_length - length $datum);
      $self->done(1);
    } elsif (length ${$self->data()} == $self->offset) {
      warn length $datum;
    }
    $self->section($self->section + 1);

    $self->make_image($datum);
}

sub new {
  my $class = shift;
  croak "Use a classname, not a reference for " . __PACKAGE__ . "::new"
    if ref $class;
  my $self = bless {}, $class;
  my %args = @_;
  my $acceptable = $self->_keys();
  foreach (keys %args) {
    croak "Unknown parameter $_" unless exists $acceptable->{$_};
    $self->set($_, $args{$_});
  }
  $self->x(352) unless $args{x};
  $self->y(288) unless $args{y};

  # Kowtow to the metadata bodging into filenames world
  $self->suffix('.png');

  $self;
}

sub type {
  'png';
}

sub write_images {
  my $self = shift;
  $self->section(0);
  $self->offset(0);
  $self->datum_length($self->calculate_datum_length());
  my $type = $self->type;
  my $filename_generator
    = $self->filename_generator || \&default_filename_generator;

  my @filenames;

  my ($filename, $state);
  while (!$self->done()) {
    my $image = $self->generate_next_image;
    ($filename, $state) = &$filename_generator($state);
    $filename .= $self->suffix;
    $image->write(file => $filename, type=> $type);
    push @filenames, $filename;
  }
  @filenames;
}

# package method
sub read_files {
  my $class = shift;
  # This is intentionally a "sparse" array to avoid some "interesting" DOS
  # possibilities.
  my $length;
  my %got;
  foreach my $file (@_) {
    my $img = new Imager;
    $img->open(file => $file) or carp "Can't read '$file': " . $img->errstr;
    my $payload = $class->extract_payload($img);
    my $datum;
    my $section;
    ($section, $datum) = unpack "wa*", $payload;
    if ($section == 0) {
      # Oops. Strip off the length.
      ($length, $datum) = unpack "wa*", $datum;
    }
    $got{$section} = $datum;