J. Duke | 319a3b9 | 2007-12-01 00:00:00 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright 1998-2007 Sun Microsystems, Inc. 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. Sun designates this |
| 8 | * particular file as subject to the "Classpath" exception as provided |
| 9 | * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
| 22 | * CA 95054 USA or visit www.sun.com if you need additional information or |
| 23 | * have any questions. |
| 24 | */ |
| 25 | |
| 26 | package javax.crypto; |
| 27 | |
| 28 | import java.security.*; |
| 29 | import java.security.spec.*; |
| 30 | |
| 31 | import java.nio.ByteBuffer; |
| 32 | |
| 33 | /** |
| 34 | * This class defines the <i>Service Provider Interface</i> (<b>SPI</b>) |
| 35 | * for the <code>Mac</code> class. |
| 36 | * All the abstract methods in this class must be implemented by each |
| 37 | * cryptographic service provider who wishes to supply the implementation |
| 38 | * of a particular MAC algorithm. |
| 39 | * |
| 40 | * <p> Implementations are free to implement the Cloneable interface. |
| 41 | * |
| 42 | * @author Jan Luehe |
| 43 | * |
| 44 | * @since 1.4 |
| 45 | */ |
| 46 | |
| 47 | public abstract class MacSpi { |
| 48 | |
| 49 | /** |
| 50 | * Returns the length of the MAC in bytes. |
| 51 | * |
| 52 | * @return the MAC length in bytes. |
| 53 | */ |
| 54 | protected abstract int engineGetMacLength(); |
| 55 | |
| 56 | /** |
| 57 | * Initializes the MAC with the given (secret) key and algorithm |
| 58 | * parameters. |
| 59 | * |
| 60 | * @param key the (secret) key. |
| 61 | * @param params the algorithm parameters. |
| 62 | * |
| 63 | * @exception InvalidKeyException if the given key is inappropriate for |
| 64 | * initializing this MAC. |
| 65 | * @exception InvalidAlgorithmParameterException if the given algorithm |
| 66 | * parameters are inappropriate for this MAC. |
| 67 | */ |
| 68 | protected abstract void engineInit(Key key, |
| 69 | AlgorithmParameterSpec params) |
| 70 | throws InvalidKeyException, InvalidAlgorithmParameterException ; |
| 71 | |
| 72 | /** |
| 73 | * Processes the given byte. |
| 74 | * |
| 75 | * @param input the input byte to be processed. |
| 76 | */ |
| 77 | protected abstract void engineUpdate(byte input); |
| 78 | |
| 79 | /** |
| 80 | * Processes the first <code>len</code> bytes in <code>input</code>, |
| 81 | * starting at <code>offset</code> inclusive. |
| 82 | * |
| 83 | * @param input the input buffer. |
| 84 | * @param offset the offset in <code>input</code> where the input starts. |
| 85 | * @param len the number of bytes to process. |
| 86 | */ |
| 87 | protected abstract void engineUpdate(byte[] input, int offset, int len); |
| 88 | |
| 89 | /** |
| 90 | * Processes <code>input.remaining()</code> bytes in the ByteBuffer |
| 91 | * <code>input</code>, starting at <code>input.position()</code>. |
| 92 | * Upon return, the buffer's position will be equal to its limit; |
| 93 | * its limit will not have changed. |
| 94 | * |
| 95 | * <p>Subclasses should consider overriding this method if they can |
| 96 | * process ByteBuffers more efficiently than byte arrays. |
| 97 | * |
| 98 | * @param input the ByteBuffer |
| 99 | * @since 1.5 |
| 100 | */ |
| 101 | protected void engineUpdate(ByteBuffer input) { |
| 102 | if (input.hasRemaining() == false) { |
| 103 | return; |
| 104 | } |
| 105 | if (input.hasArray()) { |
| 106 | byte[] b = input.array(); |
| 107 | int ofs = input.arrayOffset(); |
| 108 | int pos = input.position(); |
| 109 | int lim = input.limit(); |
| 110 | engineUpdate(b, ofs + pos, lim - pos); |
| 111 | input.position(lim); |
| 112 | } else { |
| 113 | int len = input.remaining(); |
| 114 | byte[] b = new byte[CipherSpi.getTempArraySize(len)]; |
| 115 | while (len > 0) { |
| 116 | int chunk = Math.min(len, b.length); |
| 117 | input.get(b, 0, chunk); |
| 118 | engineUpdate(b, 0, chunk); |
| 119 | len -= chunk; |
| 120 | } |
| 121 | } |
| 122 | } |
| 123 | |
| 124 | /** |
| 125 | * Completes the MAC computation and resets the MAC for further use, |
| 126 | * maintaining the secret key that the MAC was initialized with. |
| 127 | * |
| 128 | * @return the MAC result. |
| 129 | */ |
| 130 | protected abstract byte[] engineDoFinal(); |
| 131 | |
| 132 | /** |
| 133 | * Resets the MAC for further use, maintaining the secret key that the |
| 134 | * MAC was initialized with. |
| 135 | */ |
| 136 | protected abstract void engineReset(); |
| 137 | |
| 138 | /** |
| 139 | * Returns a clone if the implementation is cloneable. |
| 140 | * |
| 141 | * @return a clone if the implementation is cloneable. |
| 142 | * |
| 143 | * @exception CloneNotSupportedException if this is called |
| 144 | * on an implementation that does not support <code>Cloneable</code>. |
| 145 | */ |
| 146 | public Object clone() throws CloneNotSupportedException { |
| 147 | if (this instanceof Cloneable) { |
| 148 | return super.clone(); |
| 149 | } else { |
| 150 | throw new CloneNotSupportedException(); |
| 151 | } |
| 152 | } |
| 153 | } |