1 /* 2 * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. Oracle designates this 8 * particular file as subject to the "Classpath" exception as provided 9 * by Oracle in the LICENSE file that accompanied this code. 10 * 11 * This code is distributed in the hope that it will be useful, but WITHOUT 12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14 * version 2 for more details (a copy is included in the LICENSE file that 15 * accompanied this code). 16 * 17 * You should have received a copy of the GNU General Public License version 18 * 2 along with this work; if not, write to the Free Software Foundation, 19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 20 * 21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 22 * or visit www.oracle.com if you need additional information or have any 23 * questions. 24 */ 25 26 package java.security; 27 28 import java.io.IOException; 29 import java.io.EOFException; 30 import java.io.OutputStream; 31 import java.io.FilterOutputStream; 32 import java.io.PrintStream; 33 import java.io.ByteArrayOutputStream; 34 35 /** 36 * A transparent stream that updates the associated message digest using 37 * the bits going through the stream. 38 * 39 * <p>To complete the message digest computation, call one of the 40 * {@code digest} methods on the associated message 41 * digest after your calls to one of this digest output stream's 42 * {@link #write(int) write} methods. 43 * 44 * <p>It is possible to turn this stream on or off (see 45 * {@link #on(boolean) on}). When it is on, a call to one of the 46 * {@code write} methods results in 47 * an update on the message digest. But when it is off, the message 48 * digest is not updated. The default is for the stream to be on. 49 * 50 * @see MessageDigest 51 * @see DigestInputStream 52 * 53 * @author Benjamin Renaud 54 */ 55 public class DigestOutputStream extends FilterOutputStream { 56 57 private boolean on = true; 58 59 /** 60 * The message digest associated with this stream. 61 */ 62 protected MessageDigest digest; 63 64 /** 65 * Creates a digest output stream, using the specified output stream 66 * and message digest. 67 * 68 * @param stream the output stream. 69 * 70 * @param digest the message digest to associate with this stream. 71 */ 72 public DigestOutputStream(OutputStream stream, MessageDigest digest) { 73 super(stream); 74 setMessageDigest(digest); 75 } 76 77 /** 78 * Returns the message digest associated with this stream. 79 * 80 * @return the message digest associated with this stream. 81 * @see #setMessageDigest(java.security.MessageDigest) 82 */ 83 public MessageDigest getMessageDigest() { 84 return digest; 85 } 86 87 /** 88 * Associates the specified message digest with this stream. 89 * 90 * @param digest the message digest to be associated with this stream. 91 * @see #getMessageDigest() 92 */ 93 public void setMessageDigest(MessageDigest digest) { 94 this.digest = digest; 95 } 96 97 /** 98 * Updates the message digest (if the digest function is on) using 99 * the specified byte, and in any case writes the byte 100 * to the output stream. That is, if the digest function is on 101 * (see {@link #on(boolean) on}), this method calls 102 * {@code update} on the message digest associated with this 103 * stream, passing it the byte {@code b}. This method then 104 * writes the byte to the output stream, blocking until the byte 105 * is actually written. 106 * 107 * @param b the byte to be used for updating and writing to the 108 * output stream. 109 * 110 * @exception IOException if an I/O error occurs. 111 * 112 * @see MessageDigest#update(byte) 113 */ 114 public void write(int b) throws IOException { 115 out.write(b); 116 if (on) { 117 digest.update((byte)b); 118 } 119 } 120 121 /** 122 * Updates the message digest (if the digest function is on) using 123 * the specified subarray, and in any case writes the subarray to 124 * the output stream. That is, if the digest function is on (see 125 * {@link #on(boolean) on}), this method calls {@code update} 126 * on the message digest associated with this stream, passing it 127 * the subarray specifications. This method then writes the subarray 128 * bytes to the output stream, blocking until the bytes are actually 129 * written. 130 * 131 * @param b the array containing the subarray to be used for updating 132 * and writing to the output stream. 133 * 134 * @param off the offset into {@code b} of the first byte to 135 * be updated and written. 136 * 137 * @param len the number of bytes of data to be updated and written 138 * from {@code b}, starting at offset {@code off}. 139 * 140 * @exception IOException if an I/O error occurs. 141 * 142 * @see MessageDigest#update(byte[], int, int) 143 */ 144 public void write(byte[] b, int off, int len) throws IOException { 145 // BEGIN Android-added: perform checks for parameters first. 146 // See org.apache.harmony.security.tests.j.s.DigestOutputStreamTest#test_write$BII_6 147 if (b == null || off + len > b.length) { 148 throw new IllegalArgumentException("wrong parameters for write"); 149 } 150 if (off < 0 || len < 0) { 151 throw new IndexOutOfBoundsException("wrong index for write"); 152 } 153 // END Android-added 154 out.write(b, off, len); 155 if (on) { 156 digest.update(b, off, len); 157 } 158 } 159 160 /** 161 * Turns the digest function on or off. The default is on. When 162 * it is on, a call to one of the {@code write} methods results in an 163 * update on the message digest. But when it is off, the message 164 * digest is not updated. 165 * 166 * @param on true to turn the digest function on, false to turn it 167 * off. 168 */ 169 public void on(boolean on) { 170 this.on = on; 171 } 172 173 /** 174 * Prints a string representation of this digest output stream and 175 * its associated message digest object. 176 */ 177 public String toString() { 178 return "[Digest Output Stream] " + digest.toString(); 179 } 180 } 181
