| /* |
| * Copyright (c) 1996, 2013, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| |
| package java.security; |
| |
| import java.io.IOException; |
| import java.io.EOFException; |
| import java.io.InputStream; |
| import java.io.FilterInputStream; |
| import java.io.PrintStream; |
| import java.io.ByteArrayInputStream; |
| |
| /** |
| * A transparent stream that updates the associated message digest using |
| * the bits going through the stream. |
| * |
| * <p>To complete the message digest computation, call one of the |
| * {@code digest} methods on the associated message |
| * digest after your calls to one of this digest input stream's |
| * {@link #read() read} methods. |
| * |
| * <p>It is possible to turn this stream on or off (see |
| * {@link #on(boolean) on}). When it is on, a call to one of the |
| * {@code read} methods |
| * results in an update on the message digest. But when it is off, |
| * the message digest is not updated. The default is for the stream |
| * to be on. |
| * |
| * <p>Note that digest objects can compute only one digest (see |
| * {@link MessageDigest}), |
| * so that in order to compute intermediate digests, a caller should |
| * retain a handle onto the digest object, and clone it for each |
| * digest to be computed, leaving the original digest untouched. |
| * |
| * @see MessageDigest |
| * |
| * @see DigestOutputStream |
| * |
| * @author Benjamin Renaud |
| * @since 1.2 |
| */ |
| |
| public class DigestInputStream extends FilterInputStream { |
| |
| /* NOTE: This should be made a generic UpdaterInputStream */ |
| |
| /* Are we on or off? */ |
| private boolean on = true; |
| |
| /** |
| * The message digest associated with this stream. |
| */ |
| protected MessageDigest digest; |
| |
| /** |
| * Creates a digest input stream, using the specified input stream |
| * and message digest. |
| * |
| * @param stream the input stream. |
| * |
| * @param digest the message digest to associate with this stream. |
| */ |
| public DigestInputStream(InputStream stream, MessageDigest digest) { |
| super(stream); |
| setMessageDigest(digest); |
| } |
| |
| /** |
| * Returns the message digest associated with this stream. |
| * |
| * @return the message digest associated with this stream. |
| * @see #setMessageDigest(java.security.MessageDigest) |
| */ |
| public MessageDigest getMessageDigest() { |
| return digest; |
| } |
| |
| /** |
| * Associates the specified message digest with this stream. |
| * |
| * @param digest the message digest to be associated with this stream. |
| * @see #getMessageDigest() |
| */ |
| public void setMessageDigest(MessageDigest digest) { |
| this.digest = digest; |
| } |
| |
| /** |
| * Reads a byte, and updates the message digest (if the digest |
| * function is on). That is, this method reads a byte from the |
| * input stream, blocking until the byte is actually read. If the |
| * digest function is on (see {@link #on(boolean) on}), this method |
| * will then call {@code update} on the message digest associated |
| * with this stream, passing it the byte read. |
| * |
| * @return the byte read. |
| * |
| * @exception IOException if an I/O error occurs. |
| * |
| * @see MessageDigest#update(byte) |
| */ |
| public int read() throws IOException { |
| int ch = in.read(); |
| if (on && ch != -1) { |
| digest.update((byte)ch); |
| } |
| return ch; |
| } |
| |
| /** |
| * Reads into a byte array, and updates the message digest (if the |
| * digest function is on). That is, this method reads up to |
| * {@code len} bytes from the input stream into the array |
| * {@code b}, starting at offset {@code off}. This method |
| * blocks until the data is actually |
| * read. If the digest function is on (see |
| * {@link #on(boolean) on}), this method will then call {@code update} |
| * on the message digest associated with this stream, passing it |
| * the data. |
| * |
| * @param b the array into which the data is read. |
| * |
| * @param off the starting offset into {@code b} of where the |
| * data should be placed. |
| * |
| * @param len the maximum number of bytes to be read from the input |
| * stream into b, starting at offset {@code off}. |
| * |
| * @return the actual number of bytes read. This is less than |
| * {@code len} if the end of the stream is reached prior to |
| * reading {@code len} bytes. -1 is returned if no bytes were |
| * read because the end of the stream had already been reached when |
| * the call was made. |
| * |
| * @exception IOException if an I/O error occurs. |
| * |
| * @see MessageDigest#update(byte[], int, int) |
| */ |
| public int read(byte[] b, int off, int len) throws IOException { |
| int result = in.read(b, off, len); |
| if (on && result != -1) { |
| digest.update(b, off, result); |
| } |
| return result; |
| } |
| |
| /** |
| * Turns the digest function on or off. The default is on. When |
| * it is on, a call to one of the {@code read} methods results in an |
| * update on the message digest. But when it is off, the message |
| * digest is not updated. |
| * |
| * @param on true to turn the digest function on, false to turn |
| * it off. |
| */ |
| public void on(boolean on) { |
| this.on = on; |
| } |
| |
| /** |
| * Prints a string representation of this digest input stream and |
| * its associated message digest object. |
| */ |
| public String toString() { |
| return "[Digest Input Stream] " + digest.toString(); |
| } |
| } |