Initial catchat commit.

image_utils.rb

@@ -0,0 +1,81 @@
+require "./pixel_image.rb"
+require "digest"
+
+class ImageUtils
+  @@magickImg = nil
+  @@pixelImg = nil
+
+  @@password = ""
+  @@message = ""
+
+  @@hash = nil
+
+  def initialize(pass, msg, i)
+    @@password = pass
+    @@message  = msg
+
+    if msg.length > 400 then
+      puts "Maximum length exceeded.  Exiting."
+      exit
+    end
+
+    @@magickImg = i
+
+    @@pixelImg = PixelImage.new(@@magickImg)
+
+    self.generateHash
+  end
+
+  def getImage
+    return @@pixelImg
+  end
+
+  def generateHash
+    h = Digest::SHA512.hexdigest(@@password)
+    s = @@pixelImg.getSalt
+
+    merge_to_i = h + s
+
+    @@hash = Digest::SHA512.hexdigest(h+s)
+  end
+
+  def generateLookupTable
+    tbl = []
+
+    hash_bits = @@pixelImg.getBits(@@hash)
+    msg_bits = @@pixelImg.getBits(@@message)
+
+    # gross, but pad in the 24 bits that will become the msg length
+    # and padding bits...
+    msg_bits = msg_bits << 24
+
+    while msg_bits > 0 do
+      loc = nil
+
+      loop do
+        x = (hash_bits.to_i % @@pixelImg.getSize[:width])
+        y = (hash_bits.to_i % @@pixelImg.getSize[:height])
+
+        loc = {"x": x, "y": y}
+
+      break if !tbl.include?(loc)
+        hash_bits = hash_bits >> 1
+
+        if hash_bits <= 0 then
+          puts
+          puts "wow too much data"
+          puts "leftover bits: " + msg_bits.to_s(36)
+          exit
+        end
+      end
+
+      hash_bits = hash_bits >> 1
+
+      tbl.push(loc)
+
+      msg_bits = msg_bits >> 6
+    end
+
+    return tbl
+  end
+end