src/Pure/General/bytes.scala

 
 
 import java.io.{File => JFile, ByteArrayOutputStream, ByteArrayInputStream,
   OutputStream, InputStream, FileInputStream, FileOutputStream}
 import java.net.URL
+import java.util.Base64
 
 import org.tukaani.xz.{XZInputStream, XZOutputStream}
 
 
 object Bytes

   lazy val sha1_digest: SHA1.Digest = SHA1.digest(bytes)
 
   def text: String =
     UTF8.decode_chars(s => s, bytes, offset, offset + length).toString
 
+  def base64: String =
+  {
+    val b =
+      if (offset == 0 && length == bytes.length) bytes
+      else Bytes(bytes, offset, length).bytes
+    Base64.getEncoder.encodeToString(b)
+  }
+
   override def toString: String =
   {
     val str = text
     if (str.contains('\uFFFD')) "Bytes(" + length + ")" else str
   }