Have you read my fiber topic as it contains much info about high fiber foods. The current medical nutrition therapy for diverticulosis (no symptoms) is a high fiber nutrition therapy including nuts, but no seeds (berries, tomatoes, etc.) that can get caught in the diverticuli (pockets in the intestinal wall).
However, you say that you have diverticulitis (symptoms which may include pain and inflammation). The current medical nutrition therapy is a low fiber diet, which eliminates all raw fruits and vegetables and whole grains or cereals while you have symptoms.
Sounds like you could use some guidance. I would suggest you call your doctor’s office and ask to talk to a dietitian. It is more than just following a printed list of allowed and omitted foods.