compiled by scala 2.10.3

md5sum.scala

object md5sum {

  def main(args: Array[String]) {
    if (args.isEmpty) {
      println("Usage: scala md5sum FILE1, FILE2, ...")
      return
    }

    args.foreach{ file =>
      // calculate hash
      val hash = calcHash(file, "MD5")

      // print as hex string
      println(bytesToHexString(hash) + "  " + file)
    }
  }

  def calcHash(file: String, algo: String) = {
    val md = java.security.MessageDigest.getInstance(algo)
    val stream = try {
      new java.security.DigestInputStream(new java.io.FileInputStream(file), md)
    } catch {
      case e: java.io.FileNotFoundException => { println(e.getMessage); sys.exit(-1) }
    }
    var bytes = 0
    while (bytes != -1) bytes = stream.read()
    stream.close
    md.digest
  }

  def bytesToHexString(bytes: Array[Byte]) = {
    val sb = new java.lang.StringBuilder(bytes.size)
    val fmt = new java.util.Formatter(sb, java.util.Locale.ENGLISH)
    bytes.foreach{ b => fmt.format("%02x", byte2Byte(b)) }
    sb.toString
  }

}