require "rex/text"

module Rex
module Encoder
module NDR

	# Provide padding to align the string to the 32bit boundary
    def NDR.align(string)
        return "\x00" * ((4 - (string.length & 3)) & 3)
    end
   
    # Encode a 4 byte long
    # use to encode:
    #       long element_1;
    def NDR.long(string)
        return [string].pack('V')
    end
    
    # Encode a 2 byte short
    # use to encode:
    #       short element_1;
    def NDR.short(string)
        return [string].pack('v')
    end
    
    # Encode a single byte
    # use to encode:
    #       byte element_1;
    def NDR.byte(string)
        return [string].pack('c')
    end
   
    # Encode a byte array
    # use to encode:
    #       char  element_1
    def NDR.UniConformantArray(string)
        return long(string.length) + string + align(string)
    end

    # Encode a string
    # use to encode:
    #       char *element_1;
    def NDR.string(string)
        string += "\x00" # null pad
        return long(string.length) + long(0) + long(string.length) + string + align(string)
    end
    
    # Encode a string
    # use to encode:
    #       w_char *element_1;
    def NDR.wstring(string)
        string += "\x00" # null pad
        return long(string.length) + long(0) + long(string.length) + Rex::Text.to_unicode(string) + align(Rex::Text.to_unicode(string))
    end
	
    # Encode a string and make it unique
    # use to encode:
    #       [unique] w_char *element_1;
    def NDR.uwstring(string)
        string += "\x00" # null pad
        return long(rand(0xffffffff))+long(string.length) + long(0) + long(string.length) + Rex::Text.to_unicode(string) + align(Rex::Text.to_unicode(string))
    end
	   
    # Encode a string that is already unicode encoded
    # use to encode:
    #       w_char *element_1;
    def NDR.wstring_prebuilt(string)
        # if the string len is odd, thats bad!
        if string.length % 2 > 0
            string += "\x00"
        end
        len = string.length / 2;
        return long(len) + long(0) + long(len) + string + align(string)
    end

    # alias to wstring, going away soon
    def NDR.UnicodeConformantVaryingString(string)
        NDR.wstring(string)
    end
  
    # alias to wstring_prebuilt, going away soon
    def NDR.UnicodeConformantVaryingStringPreBuilt(string)
        NDR.wstring_prebuilt(string)
    end

end
end
end