# File ruby/ext/openssl/lib/openssl/x509.rb, line 237
def expand_hexstring(str)
  return nil unless str
  der = str.gsub(HexPair){$&.to_i(16).chr }
  a1 = OpenSSL::ASN1.decode(der)
  return a1.value, a1.tag
end

# File ruby/ext/openssl/lib/openssl/x509.rb, line 225
def expand_pair(str)
  return nil unless str
  return str.gsub(Pair){
    pair = $&
    case pair.size
    when 2 then pair[1,1]
    when 3 then Integer("0x#{pair[1,2]}").chr
    else raise OpenSSL::X509::NameError, "invalid pair: #{str}"
    end
  }
end

# File ruby/ext/openssl/lib/openssl/x509.rb, line 244
def expand_value(str1, str2, str3)
  value = expand_pair(str1)
  value, tag = expand_hexstring(str2) unless value
  value = expand_pair(str3) unless value
  return value, tag
end

# File ruby/ext/openssl/lib/openssl/x509.rb, line 251
def scan(dn)
  str = dn
  ary = []
  while true
    if md = TypeAndValue.match(str)
      remain = md.post_match
      type = md[1]
      value, tag = expand_value(md[2], md[3], md[4]) rescue nil
      if value
        type_and_value = [type, value]
        type_and_value.push(tag) if tag
        ary.unshift(type_and_value)
        if remain.length > 2 && remain[0] == ?,
          str = remain[1..-1]
          next
        elsif remain.length > 2 && remain[0] == ?+
          raise OpenSSL::X509::NameError,
            "multi-valued RDN is not supported: #{dn}"
        elsif remain.empty?
          break
        end
      end
    end
    msg_dn = dn[0, dn.length - str.length] + " =>" + str
    raise OpenSSL::X509::NameError, "malformed RDN: #{msg_dn}"
  end
  return ary
end