content: /*******************************************************************************
   * Copyright (c) 2009, 2019 Mountainminds GmbH & Co. KG and Contributors
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *    Marc R. Hoffmann - initial API and implementation
   *    
   *******************************************************************************/
  package org.jacoco.core.internal.data;
  
  import java.io.DataInputStream;
  import java.io.IOException;
  import java.io.InputStream;
  
  /**
   * Additional data input methods for compact storage of data structures.
   * 
   * @see CompactDataOutput
   */
  public class CompactDataInput extends DataInputStream {
  
  	/**
  	 * Creates a new {@link CompactDataInput} that uses the specified underlying
  	 * input stream.
  	 * 
  	 * @param in
  	 *            underlying input stream
  	 */
  	public CompactDataInput(final InputStream in) {
  		super(in);
  	}
  
  	/**
  	 * Reads a variable length representation of an integer value.
  	 * 
  	 * @return read value
  	 * @throws IOException
  	 *             if thrown by the underlying stream
  	 */
  	public int readVarInt() throws IOException {
  		final int value = 0xFF & readByte();
  		if ((value & 0x80) == 0) {
  			return value;
  		}
  		return (value & 0x7F) | (readVarInt() << 7);
  	}
  
  	/**
  	 * Reads a boolean array.
  	 * 
  	 * @return boolean array
  	 * @throws IOException
  	 *             if thrown by the underlying stream
  	 */
  	public boolean[] readBooleanArray() throws IOException {
  		final boolean[] value = new boolean[readVarInt()];
  		int buffer = 0;
  		for (int i = 0; i < value.length; i++) {
  			if ((i % 8) == 0) {
  				buffer = readByte();
  			}
  			value[i] = (buffer & 0x01) != 0;
  			buffer >>>= 1;
  		}
  		return value;
  	}
  
  }
  