1 /******************************************************************************* 2 * Copyright (c) 2009, 2018 Mountainminds GmbH & Co. KG and Contributors 3 * All rights reserved. This program and the accompanying materials 4 * are made available under the terms of the Eclipse Public License v1.0 5 * which accompanies this distribution, and is available at 6 * http://www.eclipse.org/legal/epl-v10.html 7 * 8 * Contributors: 9 * Marc R. Hoffmann - initial API and implementation 10 * 11 *******************************************************************************/ 12 package org.jacoco.core.internal.data; 13 14 import java.io.DataOutputStream; 15 import java.io.IOException; 16 import java.io.OutputStream; 17 18 /** 19 * Additional data output methods for compact storage of data structures. 20 * 21 * @see CompactDataInput 22 */ 23 public class CompactDataOutput extends DataOutputStream { 24 25 /** 26 * Creates a new {@link CompactDataOutput} instance that writes data to the 27 * specified underlying output stream 28 * 29 * @param out 30 * underlying output stream 31 */ 32 public CompactDataOutput(final OutputStream out) { 33 super(out); 34 } 35 36 /** 37 * Writes a variable length representation of an integer value that reduces 38 * the number of written bytes for small positive values. Depending on the 39 * given value 1 to 5 bytes will be written to the underlying stream. 40 * 41 * @param value 42 * value to write 43 * @throws IOException 44 * if thrown by the underlying stream 45 */ 46 public void writeVarInt(final int value) throws IOException { 47 if ((value & 0xFFFFFF80) == 0) { 48 writeByte(value); 49 } else { 50 writeByte(0x80 | (value & 0x7F)); 51 writeVarInt(value >>> 7); 52 } 53 } 54 55 /** 56 * Writes a boolean array. Internally a sequence of boolean values is packed 57 * into single bits. 58 * 59 * @param value 60 * boolean array 61 * @throws IOException 62 * if thrown by the underlying stream 63 */ 64 public void writeBooleanArray(final boolean[] value) throws IOException { 65 writeVarInt(value.length); 66 int buffer = 0; 67 int bufferSize = 0; 68 for (final boolean b : value) { 69 if (b) { 70 buffer |= 0x01 << bufferSize; 71 } 72 if (++bufferSize == 8) { 73 writeByte(buffer); 74 buffer = 0; 75 bufferSize = 0; 76 } 77 } 78 if (bufferSize > 0) { 79 writeByte(buffer); 80 } 81 } 82 83 } 84
