hexstring.rb

# Converting hexadecimal string (like: '001122deadbeaf')
# into binary string and vice-versa
 
 
def binary2hexstring(b)
  b.unpack("H*")[0]
end
 
def hexstring2binary(h)
  h.scan(/([0-9a-fA-F][0-9a-fA-F])/).collect{|v| v[0].hex.chr }.join
end
 
if __FILE__ == $0
  require 'test/unit'
  class TestBinaryString < Test::Unit::TestCase
    def sub1(teststring)
      bs = hexstring2binary(teststring)
      assert_not_nil(bs)
      hs = binary2hexstring(bs)
      assert_not_nil(hs)
      assert_equal(teststring, hs)
    end
 
    def test_run
      sub1("000102030405060708090a0b0c0d0e0f")
      sub1("36da8ed81ac6dc23c6288117bb4725f9")       # some real MD5s
      sub1("3e2530cec62f8a898ae3f75c1bb13ada")
      sub1("41aa1b20603c0faeaed350b1804e83bd")
      sub1("53570e05af1b3dc6e10f1ddec1704b90201f3890") # some real SHA1s
      sub1("5e6a4a0cdfc008b0546626b89d7be4abb368e75d")
      sub1("bdf5c5558b5354cfc663d366cd0e62591ff9f8c2")
    end
  end
end