content: /*
   * Copyright (C) 2018 The Android Open Source Project
   *
   * Licensed 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.google.android.exoplayer2.source.chunk;
  
  import java.util.NoSuchElementException;
  
  /**
   * Base class for {@link MediaChunkIterator}s. Handles {@link #next()} and {@link #isEnded()}, and
   * provides a bounds check for child classes.
   */
  public abstract class BaseMediaChunkIterator implements MediaChunkIterator {
  
    private final long fromIndex;
    private final long toIndex;
  
    private long currentIndex;
  
    /**
     * Creates base iterator.
     *
     * @param fromIndex The first available index.
     * @param toIndex The last available index.
     */
    @SuppressWarnings("nullness:method.invocation")
    public BaseMediaChunkIterator(long fromIndex, long toIndex) {
      this.fromIndex = fromIndex;
      this.toIndex = toIndex;
      reset();
    }
  
    @Override
    public boolean isEnded() {
      return currentIndex > toIndex;
    }
  
    @Override
    public boolean next() {
      currentIndex++;
      return !isEnded();
    }
  
    @Override
    public void reset() {
      currentIndex = fromIndex - 1;
    }
  
    /**
     * Verifies that the iterator points to a valid element.
     *
     * @throws NoSuchElementException If the iterator does not point to a valid element.
     */
    protected final void checkInBounds() {
      if (currentIndex < fromIndex || currentIndex > toIndex) {
        throw new NoSuchElementException();
      }
    }
  
    /** Returns the current index this iterator is pointing to. */
    protected final long getCurrentIndex() {
      return currentIndex;
    }
  }
  