content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.datastax.dse.driver.internal.core.cql.reactive;
  
  import edu.umd.cs.findbugs.annotations.NonNull;
  import java.util.concurrent.atomic.AtomicLong;
  
  public final class ReactiveOperators {
  
    /**
     * Atomically adds the given value to the given AtomicLong, bound to Long.MAX_VALUE.
     *
     * @param current the current value.
     * @param toAdd the delta to add.
     */
    public static void addCap(@NonNull AtomicLong current, long toAdd) {
      long r, u;
      do {
        r = current.get();
        if (r == Long.MAX_VALUE) {
          return;
        }
        u = r + toAdd;
        if (u < 0L) {
          u = Long.MAX_VALUE;
        }
      } while (!current.compareAndSet(r, u));
    }
  
    /**
     * Atomically subtracts the given value from the given AtomicLong, bound to 0.
     *
     * @param current the current value.
     * @param toSub the delta to subtract.
     */
    public static void subCap(@NonNull AtomicLong current, long toSub) {
      long r, u;
      do {
        r = current.get();
        if (r == 0 || r == Long.MAX_VALUE) {
          return;
        }
        u = Math.max(r - toSub, 0);
      } while (!current.compareAndSet(r, u));
    }
  }
  