Method writing nibbles for Add/Data parts of Sections

src/main/java/mregioneer/utils/Helpers.java

@@ -4,11 +4,25 @@
 public class Helpers {
     /**
      * Helps to calculate offset for Add and Data sections which are known to keep 4 bits for a block
-     * @param arr
-     * @param index
+     * @param arr nibble array
+     * @param index index of correlated 'Blocks' id
      * @return
      */
     public static byte Nibble4(byte[] arr, int index){
         return (byte) (index%2 == 0 ? arr[index/2]&0x0F : (arr[index/2]>>4)&0x0F);
     }
+
+
+    /**
+     * Writes a nibble into an nibble array. Method is used when we write id to Data or Add parts of sections.
+     * @param arr nibble array
+     * @param value value to be inserted
+     * @param offset index of correlated 'Blocks' id
+     */
+    public static byte[] writeNibble4(byte[] arr, byte value, int offset) {
+        int shift = (offset % 2) << 2;
+        arr[offset/2] = (byte) ((arr[offset/2] & (0xF0 >> shift)) | ((value &0xF) << shift));
+
+        return arr;
+    }
 }