Class: ZSteg::CLI::Mask

Inherits:
Object
  • Object
show all
Defined in:
lib/zsteg/cli/mask.rb

Constant Summary collapse

DEFAULT_ACTIONS = 
%w'mask'
COMMON_MASKS = 
[
  0b0000_0001, 0b0000_0011, 0b0000_0111, 0b0000_1111,
               0b0000_0010, 0b0000_0100, 0b0000_1000,
  0b0001_0000, 0b0010_0000, 0b0100_0000, 0b1000_0000,
]
CHANNELS = 
[:r, :g, :b, :a]

Instance Method Summary collapse

Constructor Details

#initialize(argv = ARGV) ⇒ Mask

Returns a new instance of Mask.



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# File 'lib/zsteg/cli/mask.rb', line 17

def initialize argv = ARGV
  @argv = argv
  @wasfiles = Set.new
  @cache = {}
end

Instance Method Details

#load_image(fname) ⇒ Object 



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# File 'lib/zsteg/cli/mask.rb', line 141

def load_image fname
  if File.directory?(fname)
    puts "[?] #{fname} is a directory".yellow
  else
    ZPNG::Image.load(fname)
  end
rescue ZPNG::Exception, Errno::ENOENT
  puts "[!] #{$!.inspect}".red
end

#mask ⇒ Object

actions



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# File 'lib/zsteg/cli/mask.rb', line 154

def mask
  masks = @options[:masks]
  masks.each{ |k,v| v.flatten!; v.uniq! }

  if @options[:try_all]
    # try all common masks
    masks = masks[:all] || []
    masks = COMMON_MASKS if masks.empty?
    masks.each{ |x| run_masker x,x,x,x    }
    masks.each{ |x| run_masker x,0,0,0xff }
    masks.each{ |x| run_masker 0,x,0,0xff }
    masks.each{ |x| run_masker 0,0,x,0xff }
    if @image.alpha_used?
      masks.each{ |x| run_masker 0,0,0,x    }
    end

  elsif CHANNELS.all?{ |c| !masks[c] || masks[c].empty? }
    # no specific channels
    masks[:all].each do |x|
      run_masker x,x,x,x
    end

  else
    # specific channels
    CHANNELS.each{ |x| masks[x] = [x==:a ? 0xff : 0] if !masks[x] || masks[x].empty? }
    masks[:r].each do |r|
      masks[:g].each do |g|
        masks[:b].each do |b|
          if @image.alpha_used?
            masks[:a].each do |a|
              run_masker r,g,b,a
            end
          else
            run_masker r,g,b,0xff
          end
        end
      end
    end
  end
end

#parse_mask(x) ⇒ Object 



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# File 'lib/zsteg/cli/mask.rb', line 127

def parse_mask x
  case x
  when /0x/i
    x.to_i(16)
  when /^[01]{8}$/
    x.to_i(2)
  when /^\d{1,3}$/
    x.to_i
  when /^all$/
    COMMON_MASKS
  else raise "invalid mask #{x.inspect}"
  end
end

#run ⇒ Object 



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# File 'lib/zsteg/cli/mask.rb', line 23

def run
  @actions = []
  @options = {
    :verbose   => 0,
    :masks     => Hash.new{|k,v| k[v] = [] },
    :normalize => true
  }
  optparser = OptionParser.new do |opts|
    opts.banner = "Usage: zsteg-mask [options] filename.png [param_string]"
    opts.separator ""

    opts.on("-m", "--mask M", "apply mask to all channels",
            "mask: 0-255 OR 0x00-0xff OR 00000000-11111111",
            "OR 'all' for all common masks"
    ){ |x| @options[:masks][:all] << parse_mask(x) }

    opts.on("-R", "--red M", "red channel mask"){ |x|
      @options[:masks][:r] << parse_mask(x) }

    opts.on("-G", "--green M", "green channel mask"){ |x|
      @options[:masks][:g] << parse_mask(x) }

    opts.on("-B", "--blue M", "blue channel mask"){ |x|
      @options[:masks][:b] << parse_mask(x) }

    opts.on("-A", "--alpha M", "alpha channel mask"){ |x|
      @options[:masks][:a] << parse_mask(x) }

    opts.separator ""

    opts.on "-a", "--all", "try all common masks (default)" do
      @options[:try_all] = true
    end

    opts.separator ""

    opts.on "-N", "--[no-]normalize", "normalize color value after applying mask",
      "(default: normalize)" do |x|
      @options[:normalize] = x
    end

    opts.on "-O", "--outfile FILENAME", "output single result to specified file" do |x|
      @options[:outfile] = x
    end

    opts.on "-D", "--dir DIRNAME", "output multiple results to specified dir" do |x|
      @options[:dir] = x
    end

    opts.separator ""
    opts.on "-v", "--verbose", "Run verbosely (can be used multiple times)" do |v|
      @options[:verbose] += 1
    end
    opts.on "-q", "--quiet", "Silent any warnings (can be used multiple times)" do |v|
      @options[:verbose] -= 1
    end
    opts.on "-C", "--[no-]color", "Force (or disable) color output (default: auto)" do |x|
      if defined?(Rainbow) && Rainbow.respond_to?(:enabled=)
        Rainbow.enabled = x
      else
        Sickill::Rainbow.enabled = x
      end
    end
  end

  if (argv = optparser.parse(@argv)).empty?
    puts optparser.help
    return
  end

  # default :all mask if none specified
  if @options[:masks].empty?
    @options[:try_all] = true
  end

  @actions = DEFAULT_ACTIONS if @actions.empty?

  argv.each do |arg|
    if arg[','] && !File.exist?(arg)
      @options.merge!(decode_param_string(arg))
      argv.delete arg
    end
  end

  argv.each_with_index do |fname,idx|
    if argv.size > 1 && @options[:verbose] >= 0
      puts if idx > 0
      puts "[.] #{fname}".green
    end
    next unless @image=load_image(@fname=fname)

    @actions.each do |action|
      if action.is_a?(Array)
        self.send(*action) if self.respond_to?(action.first)
      else
        self.send(action) if self.respond_to?(action)
      end
    end
  end
rescue Errno::EPIPE
  # output interrupt, f.ex. when piping output to a 'head' command
  # prevents a 'Broken pipe - <STDOUT> (Errno::EPIPE)' message
end