code: private boolean matches(File file, byte[] digest, Configuration conf) throws IOException {
      byte[] fileDigest = getDigest(file, conf);
      return Arrays.equals(fileDigest, digest);
    }
docs: Determines whether the digest of the specified file matches the given
  digest.
  @param file The <code>File</code> to check.
  @param digest The digest to compare against.
  @param conf The application command line options.
  @return A value indicating whether the digest of the specified file
  matches the given digest.
  @throws IOException If an error occurs while trying to read the file.