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My first initial commit with all of mine experimental changes.

Dmitry Kabak (userdima committed 13 years ago

Commit d37b88d1 parent 3f5b46618352 files · +2598093 −-8690Browse files

Showing the changes to java/pkg/java/security/DigestInputStream.java (1 of 18352 files). Show all

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java/pkg/java/security/DigestInputStream.java+188−0
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1+/*
2+ * Copyright (c) 1996, 1999, 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.InputStream;
31+import java.io.FilterInputStream;
32+import java.io.PrintStream;
33+import java.io.ByteArrayInputStream;
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</code> methods on the associated message
41+ * digest after your calls to one of this digest input stream's
42+ * {@link #read() read} 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>read</code> methods
47+ * results in an update on the message digest. But when it is off,
48+ * the message digest is not updated. The default is for the stream
49+ * to be on.
50+ *
51+ * <p>Note that digest objects can compute only one digest (see
52+ * {@link MessageDigest}),
53+ * so that in order to compute intermediate digests, a caller should
54+ * retain a handle onto the digest object, and clone it for each
55+ * digest to be computed, leaving the orginal digest untouched.
56+ *
57+ * @see MessageDigest
58+ *
59+ * @see DigestOutputStream
60+ *
61+ * @author Benjamin Renaud
62+ */
63+
64+public class DigestInputStream extends FilterInputStream {
65+
66+ /* NOTE: This should be made a generic UpdaterInputStream */
67+
68+ /* Are we on or off? */
69+ private boolean on = true;
70+
71+ /**
72+ * The message digest associated with this stream.
73+ */
74+ protected MessageDigest digest;
75+
76+ /**
77+ * Creates a digest input stream, using the specified input stream
78+ * and message digest.
79+ *
80+ * @param stream the input stream.
81+ *
82+ * @param digest the message digest to associate with this stream.
83+ */
84+ public DigestInputStream(InputStream stream, MessageDigest digest) {
85+ super(stream);
86+ setMessageDigest(digest);
87+ }
88+
89+ /**
90+ * Returns the message digest associated with this stream.
91+ *
92+ * @return the message digest associated with this stream.
93+ * @see #setMessageDigest(java.security.MessageDigest)
94+ */
95+ public MessageDigest getMessageDigest() {
96+ return digest;
97+ }
98+
99+ /**
100+ * Associates the specified message digest with this stream.
101+ *
102+ * @param digest the message digest to be associated with this stream.
103+ * @see #getMessageDigest()
104+ */
105+ public void setMessageDigest(MessageDigest digest) {
106+ this.digest = digest;
107+ }
108+
109+ /**
110+ * Reads a byte, and updates the message digest (if the digest
111+ * function is on). That is, this method reads a byte from the
112+ * input stream, blocking until the byte is actually read. If the
113+ * digest function is on (see {@link #on(boolean) on}), this method
114+ * will then call <code>update</code> on the message digest associated
115+ * with this stream, passing it the byte read.
116+ *
117+ * @return the byte read.
118+ *
119+ * @exception IOException if an I/O error occurs.
120+ *
121+ * @see MessageDigest#update(byte)
122+ */
123+ public int read() throws IOException {
124+ int ch = in.read();
125+ if (on && ch != -1) {
126+ digest.update((byte)ch);
127+ }
128+ return ch;
129+ }
130+
131+ /**
132+ * Reads into a byte array, and updates the message digest (if the
133+ * digest function is on). That is, this method reads up to
134+ * <code>len</code> bytes from the input stream into the array
135+ * <code>b</code>, starting at offset <code>off</code>. This method
136+ * blocks until the data is actually
137+ * read. If the digest function is on (see
138+ * {@link #on(boolean) on}), this method will then call <code>update</code>
139+ * on the message digest associated with this stream, passing it
140+ * the data.
141+ *
142+ * @param b the array into which the data is read.
143+ *
144+ * @param off the starting offset into <code>b</code> of where the
145+ * data should be placed.
146+ *
147+ * @param len the maximum number of bytes to be read from the input
148+ * stream into b, starting at offset <code>off</code>.
149+ *
150+ * @return the actual number of bytes read. This is less than
151+ * <code>len</code> if the end of the stream is reached prior to
152+ * reading <code>len</code> bytes. -1 is returned if no bytes were
153+ * read because the end of the stream had already been reached when
154+ * the call was made.
155+ *
156+ * @exception IOException if an I/O error occurs.
157+ *
158+ * @see MessageDigest#update(byte[], int, int)
159+ */
160+ public int read(byte[] b, int off, int len) throws IOException {
161+ int result = in.read(b, off, len);
162+ if (on && result != -1) {
163+ digest.update(b, off, result);
164+ }
165+ return result;
166+ }
167+
168+ /**
169+ * Turns the digest function on or off. The default is on. When
170+ * it is on, a call to one of the <code>read</code> methods results in an
171+ * update on the message digest. But when it is off, the message
172+ * digest is not updated.
173+ *
174+ * @param on true to turn the digest function on, false to turn
175+ * it off.
176+ */
177+ public void on(boolean on) {
178+ this.on = on;
179+ }
180+
181+ /**
182+ * Prints a string representation of this digest input stream and
183+ * its associated message digest object.
184+ */
185+ public String toString() {
186+ return "[Digest Input Stream] " + digest.toString();
187+ }
188+}