jdk/src/java.base/share/classes/javax/crypto/CipherOutputStream.java
changeset 25859 3317bb8137f4
parent 25176 3c2ba9344cbf
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/java.base/share/classes/javax/crypto/CipherOutputStream.java	Sun Aug 17 15:54:13 2014 +0100
@@ -0,0 +1,214 @@
+/*
+ * Copyright (c) 1997, 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 javax.crypto;
+
+import java.io.*;
+
+/**
+ * A CipherOutputStream is composed of an OutputStream and a Cipher so
+ * that write() methods first process the data before writing them out
+ * to the underlying OutputStream.  The cipher must be fully
+ * initialized before being used by a CipherOutputStream.
+ *
+ * <p> For example, if the cipher is initialized for encryption, the
+ * CipherOutputStream will attempt to encrypt data before writing out the
+ * encrypted data.
+ *
+ * <p> This class adheres strictly to the semantics, especially the
+ * failure semantics, of its ancestor classes
+ * java.io.OutputStream and java.io.FilterOutputStream.  This class
+ * has exactly those methods specified in its ancestor classes, and
+ * overrides them all.  Moreover, this class catches all exceptions
+ * that are not thrown by its ancestor classes.
+ *
+ * <p> It is crucial for a programmer using this class not to use
+ * methods that are not defined or overriden in this class (such as a
+ * new method or constructor that is later added to one of the super
+ * classes), because the design and implementation of those methods
+ * are unlikely to have considered security impact with regard to
+ * CipherOutputStream.
+ *
+ * @author  Li Gong
+ * @see     java.io.OutputStream
+ * @see     java.io.FilterOutputStream
+ * @see     javax.crypto.Cipher
+ * @see     javax.crypto.CipherInputStream
+ *
+ * @since 1.4
+ */
+
+public class CipherOutputStream extends FilterOutputStream {
+
+    // the cipher engine to use to process stream data
+    private Cipher cipher;
+
+    // the underlying output stream
+    private OutputStream output;
+
+    /* the buffer holding one byte of incoming data */
+    private byte[] ibuffer = new byte[1];
+
+    // the buffer holding data ready to be written out
+    private byte[] obuffer;
+
+    // stream status
+    private boolean closed = false;
+
+    /**
+     *
+     * Constructs a CipherOutputStream from an OutputStream and a
+     * Cipher.
+     * <br>Note: if the specified output stream or cipher is
+     * null, a NullPointerException may be thrown later when
+     * they are used.
+     *
+     * @param os  the OutputStream object
+     * @param c   an initialized Cipher object
+     */
+    public CipherOutputStream(OutputStream os, Cipher c) {
+        super(os);
+        output = os;
+        cipher = c;
+    };
+
+    /**
+     * Constructs a CipherOutputStream from an OutputStream without
+     * specifying a Cipher. This has the effect of constructing a
+     * CipherOutputStream using a NullCipher.
+     * <br>Note: if the specified output stream is null, a
+     * NullPointerException may be thrown later when it is used.
+     *
+     * @param os  the OutputStream object
+     */
+    protected CipherOutputStream(OutputStream os) {
+        super(os);
+        output = os;
+        cipher = new NullCipher();
+    }
+
+    /**
+     * Writes the specified byte to this output stream.
+     *
+     * @param      b   the <code>byte</code>.
+     * @exception  IOException  if an I/O error occurs.
+     */
+    public void write(int b) throws IOException {
+        ibuffer[0] = (byte) b;
+        obuffer = cipher.update(ibuffer, 0, 1);
+        if (obuffer != null) {
+            output.write(obuffer);
+            obuffer = null;
+        }
+    };
+
+    /**
+     * Writes <code>b.length</code> bytes from the specified byte array
+     * to this output stream.
+     * <p>
+     * The <code>write</code> method of
+     * <code>CipherOutputStream</code> calls the <code>write</code>
+     * method of three arguments with the three arguments
+     * <code>b</code>, <code>0</code>, and <code>b.length</code>.
+     *
+     * @param      b   the data.
+     * @exception  NullPointerException if <code>b</code> is null.
+     * @exception  IOException  if an I/O error occurs.
+     * @see        javax.crypto.CipherOutputStream#write(byte[], int, int)
+     */
+    public void write(byte b[]) throws IOException {
+        write(b, 0, b.length);
+    }
+
+    /**
+     * Writes <code>len</code> bytes from the specified byte array
+     * starting at offset <code>off</code> to this output stream.
+     *
+     * @param      b     the data.
+     * @param      off   the start offset in the data.
+     * @param      len   the number of bytes to write.
+     * @exception  IOException  if an I/O error occurs.
+     */
+    public void write(byte b[], int off, int len) throws IOException {
+        obuffer = cipher.update(b, off, len);
+        if (obuffer != null) {
+            output.write(obuffer);
+            obuffer = null;
+        }
+    }
+
+    /**
+     * Flushes this output stream by forcing any buffered output bytes
+     * that have already been processed by the encapsulated cipher object
+     * to be written out.
+     *
+     * <p>Any bytes buffered by the encapsulated cipher
+     * and waiting to be processed by it will not be written out. For example,
+     * if the encapsulated cipher is a block cipher, and the total number of
+     * bytes written using one of the <code>write</code> methods is less than
+     * the cipher's block size, no bytes will be written out.
+     *
+     * @exception  IOException  if an I/O error occurs.
+     */
+    public void flush() throws IOException {
+        if (obuffer != null) {
+            output.write(obuffer);
+            obuffer = null;
+        }
+        output.flush();
+    }
+
+    /**
+     * Closes this output stream and releases any system resources
+     * associated with this stream.
+     * <p>
+     * This method invokes the <code>doFinal</code> method of the encapsulated
+     * cipher object, which causes any bytes buffered by the encapsulated
+     * cipher to be processed. The result is written out by calling the
+     * <code>flush</code> method of this output stream.
+     * <p>
+     * This method resets the encapsulated cipher object to its initial state
+     * and calls the <code>close</code> method of the underlying output
+     * stream.
+     *
+     * @exception  IOException  if an I/O error occurs.
+     */
+    public void close() throws IOException {
+        if (closed) {
+            return;
+        }
+
+        closed = true;
+        try {
+            obuffer = cipher.doFinal();
+        } catch (IllegalBlockSizeException | BadPaddingException e) {
+            obuffer = null;
+        }
+        try {
+            flush();
+        } catch (IOException ignored) {}
+        out.close();
+    }
+}