code: public OMVRBTreeEntry<K, V> getPreviousInMemory() {
      OMVRBTreeEntry<K, V> t = this;
      OMVRBTreeEntry<K, V> p = null;
  
      if (t.getLeftInMemory() != null) {
        p = t.getLeftInMemory();
        while (p.getRightInMemory() != null)
          p = p.getRightInMemory();
      } else {
        p = t.getParentInMemory();
        while (p != null && t == p.getLeftInMemory()) {
          t = p;
          p = p.getParentInMemory();
        }
      }
  
      return p;
    }
docs: Returns the previous of the current Entry only by traversing the memory, or null if no such.