Adding byte functions for UUIDs (apache#11988)

pinot-common/src/main/java/org/apache/pinot/common/function/scalar/StringFunctions.java

@@ -21,9 +21,11 @@
 import java.io.UnsupportedEncodingException;
 import java.net.URLDecoder;
 import java.net.URLEncoder;
+import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
 import java.text.Normalizer;
 import java.util.Base64;
+import java.util.UUID;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import org.apache.commons.lang3.StringUtils;
@@ -493,6 +495,37 @@ public static byte[] toAscii(String input) {
     return input.getBytes(StandardCharsets.US_ASCII);
   }
 
+  /**
+   * @param input UUID as string
+   * @return bytearray
+   * returns bytes and null on exception
+   */
+  @ScalarFunction
+  public static byte[] toUUIDBytes(String input) {
+    try {
+      UUID uuid = UUID.fromString(input);
+      ByteBuffer bb = ByteBuffer.wrap(new byte[16]);
+      bb.putLong(uuid.getMostSignificantBits());
+      bb.putLong(uuid.getLeastSignificantBits());
+      return bb.array();
+    } catch (IllegalArgumentException e) {
+      return null;
+    }
+  }
+
+  /**
+   * @param input UUID serialized to bytes
+   * @return String representation of UUID
+   * returns bytes and null on exception
+   */
+  @ScalarFunction
+  public static String fromUUIDBytes(byte[] input) {
+    ByteBuffer bb = ByteBuffer.wrap(input);
+    long firstLong = bb.getLong();
+    long secondLong = bb.getLong();
+    return new UUID(firstLong, secondLong).toString();
+  }
+
   /**
    * @see Normalizer#normalize(CharSequence, Normalizer.Form)
    * @param input