2362N/A * Copyright (c) 1997, 2007, Oracle and/or its affiliates. All rights reserved. 0N/A * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 0N/A * This code is free software; you can redistribute it and/or modify it 0N/A * under the terms of the GNU General Public License version 2 only, as 2362N/A * published by the Free Software Foundation. Oracle designates this 0N/A * particular file as subject to the "Classpath" exception as provided 2362N/A * by Oracle in the LICENSE file that accompanied this code. 0N/A * This code is distributed in the hope that it will be useful, but WITHOUT 0N/A * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 0N/A * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 0N/A * version 2 for more details (a copy is included in the LICENSE file that 0N/A * accompanied this code). 0N/A * You should have received a copy of the GNU General Public License version 0N/A * 2 along with this work; if not, write to the Free Software Foundation, 0N/A * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 2362N/A * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 2362N/A * or visit www.oracle.com if you need additional information or have any 0N/A * A CipherInputStream is composed of an InputStream and a Cipher so 0N/A * that read() methods return data that are read in from the 0N/A * underlying InputStream but have been additionally processed by the 0N/A * Cipher. The Cipher must be fully initialized before being used by 0N/A * a CipherInputStream. 0N/A * <p> For example, if the Cipher is initialized for decryption, the 0N/A * CipherInputStream will attempt to read in data and decrypt them, 0N/A * before returning the decrypted data. 0N/A * <p> This class adheres strictly to the semantics, especially the 0N/A * failure semantics, of its ancestor classes 0N/A * java.io.FilterInputStream and java.io.InputStream. This class has 0N/A * exactly those methods specified in its ancestor classes, and 0N/A * overrides them all. Moreover, this class catches all exceptions 0N/A * that are not thrown by its ancestor classes. In particular, the 0N/A * <code>skip</code> method skips, and the <code>available</code> 0N/A * method counts only data that have been processed by the encapsulated Cipher. 0N/A * <p> It is crucial for a programmer using this class not to use 0N/A * methods that are not defined or overriden in this class (such as a 0N/A * new method or constructor that is later added to one of the super 0N/A * classes), because the design and implementation of those methods 0N/A * are unlikely to have considered security impact with regard to 0N/A * CipherInputStream. 0N/A * @see java.io.InputStream 0N/A * @see java.io.FilterInputStream 0N/A * @see javax.crypto.Cipher 0N/A * @see javax.crypto.CipherOutputStream 0N/A // the cipher engine to use to process stream data 0N/A // the underlying input stream 0N/A /* the buffer holding data that have been read in from the 0N/A underlying stream, but have not been processed by the cipher 0N/A engine. the size 512 bytes is somewhat randomly chosen */ 0N/A // having reached the end of the underlying input stream 0N/A /* the buffer holding data that have been processed by the cipher 0N/A engine, but have not been read out */ 0N/A // the offset pointing to the next "new" byte 0N/A // the offset pointing to the last "new" byte 0N/A * private convenience function. 0N/A * Entry condition: ostart = ofinish 0N/A * Exit condition: ostart <= ofinish 0N/A * return (ofinish-ostart) (we have this many bytes for you) 0N/A * return 0 (no data now, but could have more later) 0N/A * return -1 (absolutely no more data) 0N/A * Constructs a CipherInputStream from an InputStream and a 0N/A * <br>Note: if the specified input stream or cipher is 0N/A * null, a NullPointerException may be thrown later when 0N/A * @param is the to-be-processed input stream 0N/A * @param c an initialized Cipher object 0N/A * Constructs a CipherInputStream from an InputStream without 0N/A * specifying a Cipher. This has the effect of constructing a 0N/A * CipherInputStream using a NullCipher. 0N/A * <br>Note: if the specified input stream is null, a 0N/A * NullPointerException may be thrown later when it is used. 0N/A * @param is the to-be-processed input stream 0N/A * Reads the next byte of data from this input stream. The value 0N/A * byte is returned as an <code>int</code> in the range 0N/A * <code>0</code> to <code>255</code>. If no byte is available 0N/A * because the end of the stream has been reached, the value 0N/A * <code>-1</code> is returned. This method blocks until input data 0N/A * is available, the end of the stream is detected, or an exception 0N/A * @return the next byte of data, or <code>-1</code> if the end of the 0N/A * stream is reached. 0N/A * @exception IOException if an I/O error occurs. 0N/A // we loop for new data as the spec says we are blocking 0N/A if (i == -
1)
return -
1;
0N/A * Reads up to <code>b.length</code> bytes of data from this input 0N/A * stream into an array of bytes. 0N/A * The <code>read</code> method of <code>InputStream</code> calls 0N/A * the <code>read</code> method of three arguments with the arguments 0N/A * <code>b</code>, <code>0</code>, and <code>b.length</code>. 0N/A * @param b the buffer into which the data is read. 0N/A * @return the total number of bytes read into the buffer, or 0N/A * <code>-1</code> is there is no more data because the end of 0N/A * the stream has been reached. 0N/A * @exception IOException if an I/O error occurs. 0N/A * @see java.io.InputStream#read(byte[], int, int) 0N/A * Reads up to <code>len</code> bytes of data from this input stream 0N/A * into an array of bytes. This method blocks until some input is 0N/A * available. If the first argument is <code>null,</code> up to 0N/A * <code>len</code> bytes are read and discarded. 0N/A * @param b the buffer into which the data is read. 0N/A * @param off the start offset in the destination array 0N/A * @param len the maximum number of bytes read. 0N/A * @return the total number of bytes read into the buffer, or 0N/A * <code>-1</code> if there is no more data because the end of 0N/A * the stream has been reached. 0N/A * @exception IOException if an I/O error occurs. 0N/A * @see java.io.InputStream#read() 0N/A // we loop for new data as the spec says we are blocking 0N/A if (i == -
1)
return -
1;
0N/A * Skips <code>n</code> bytes of input from the bytes that can be read 0N/A * from this input stream without blocking. 0N/A * <p>Fewer bytes than requested might be skipped. 0N/A * The actual number of bytes skipped is equal to <code>n</code> or 0N/A * the result of a call to 0N/A * {@link #available() <code>available</code>}, 0N/A * whichever is smaller. 0N/A * If <code>n</code> is less than zero, no bytes are skipped. 0N/A * <p>The actual number of bytes skipped is returned. 0N/A * @param n the number of bytes to be skipped. 0N/A * @return the actual number of bytes skipped. 0N/A * @exception IOException if an I/O error occurs. 0N/A * Returns the number of bytes that can be read from this input 0N/A * stream without blocking. The <code>available</code> method of 0N/A * <code>InputStream</code> returns <code>0</code>. This method 0N/A * <B>should</B> be overridden by subclasses. 0N/A * @return the number of bytes that can be read from this input stream 0N/A * @exception IOException if an I/O error occurs. 0N/A * Closes this input stream and releases any system resources 0N/A * associated with the stream. 0N/A * The <code>close</code> method of <code>CipherInputStream</code> 0N/A * calls the <code>close</code> method of its underlying input 0N/A * @exception IOException if an I/O error occurs. 0N/A // throw away the unprocessed data 0N/A * Tests if this input stream supports the <code>mark</code> 0N/A * and <code>reset</code> methods, which it does not. 0N/A * @return <code>false</code>, since this class does not support the 0N/A * <code>mark</code> and <code>reset</code> methods. 0N/A * @see java.io.InputStream#mark(int) 0N/A * @see java.io.InputStream#reset()