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1: /* MacSpi.java -- The MAC service provider interface. 2: Copyright (C) 2004 Free Software Foundation, Inc. 3: 4: This file is part of GNU Classpath. 5: 6: GNU Classpath is free software; you can redistribute it and/or modify 7: it under the terms of the GNU General Public License as published by 8: the Free Software Foundation; either version 2, or (at your option) 9: any later version. 10: 11: GNU Classpath is distributed in the hope that it will be useful, but 12: WITHOUT ANY WARRANTY; without even the implied warranty of 13: MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14: General Public License for more details. 15: 16: You should have received a copy of the GNU General Public License 17: along with GNU Classpath; see the file COPYING. If not, write to the 18: Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 19: 02110-1301 USA. 20: 21: Linking this library statically or dynamically with other modules is 22: making a combined work based on this library. Thus, the terms and 23: conditions of the GNU General Public License cover the whole 24: combination. 25: 26: As a special exception, the copyright holders of this library give you 27: permission to link this library with independent modules to produce an 28: executable, regardless of the license terms of these independent 29: modules, and to copy and distribute the resulting executable under 30: terms of your choice, provided that you also meet, for each linked 31: independent module, the terms and conditions of the license of that 32: module. An independent module is a module which is not derived from 33: or based on this library. If you modify this library, you may extend 34: this exception to your version of the library, but you are not 35: obligated to do so. If you do not wish to do so, delete this 36: exception statement from your version. */ 37: 38: 39: package javax.crypto; 40: 41: import java.nio.ByteBuffer; 42: import java.security.InvalidAlgorithmParameterException; 43: import java.security.InvalidKeyException; 44: import java.security.Key; 45: import java.security.spec.AlgorithmParameterSpec; 46: 47: /** 48: * This is the <i>Service Provider Interface</i> (<b>SPI</b>) for the 49: * {@link Mac} class. 50: * 51: * <p>Providers wishing to implement a Mac must subclass this class and 52: * provide appropriate implementations of all its abstract methods, 53: * then provide an entry pointing to this implementation in the master 54: * {@link java.security.Provider} class. 55: * 56: * <p>Implementations may optionally implement the {@link 57: * java.lang.Cloneable} interface. 58: * 59: * @author Casey Marshall (csm@gnu.org) 60: * @since 1.4 61: */ 62: public abstract class MacSpi 63: { 64: 65: // Constructor. 66: // ------------------------------------------------------------------------ 67: 68: /** 69: * Create a new MacSpi instance. 70: */ 71: public MacSpi() 72: { 73: } 74: 75: // Instance methods. 76: // ------------------------------------------------------------------------ 77: 78: /** 79: * Returns a clone of this instance if cloning is supported. 80: * 81: * @return A clone of this instance. 82: * @throws java.lang.CloneNotSupportedException If this instance does 83: * not support cloneing. 84: */ 85: public Object clone() throws CloneNotSupportedException 86: { 87: return super.clone(); 88: } 89: 90: // Abstract instance methods. 91: // ------------------------------------------------------------------------ 92: 93: /** 94: * Finalize the computation of this MAC and return the result as a 95: * byte array. 96: * 97: * @return The MAC. 98: */ 99: protected abstract byte[] engineDoFinal(); 100: 101: /** 102: * Return the total length, in bytes, of the computed MAC (the length 103: * of the byte array returned by {@link #doFinal()}. 104: * 105: * @return The MAC length. 106: */ 107: protected abstract int engineGetMacLength(); 108: 109: /** 110: * Initialize (or re-initialize) this instance. 111: * 112: * @param key The key to use. 113: * @param params The parameters to use. 114: * @throws java.security.InvalidAlgorithmParameterException If this 115: * instance rejects the specified parameters. 116: * @throws java.security.InvalidKeyException If this instance rejects 117: * the specified key. 118: */ 119: protected abstract void engineInit(Key key, AlgorithmParameterSpec params) 120: throws InvalidAlgorithmParameterException, InvalidKeyException; 121: 122: /** 123: * Reset this instance. After this method succeeds, the state of this 124: * instance should be the same as it was before any data was input 125: * (possibly after a call to {@link 126: * #init(java.security.Key,java.security.spec.AlgorithmParameterSpec)}, 127: * possibly not). 128: */ 129: protected abstract void engineReset(); 130: 131: /** 132: * Update this MAC with a single byte. 133: * 134: * @param input The next byte. 135: */ 136: protected abstract void engineUpdate(byte input); 137: 138: /** 139: * Update this MAC with a portion of a byte array. 140: * 141: * @param input The next bytes. 142: * @param offset The index in <code>input</code> at which to start. 143: * @param length The number of bytes to update. 144: */ 145: protected abstract void engineUpdate(byte[] input, int offset, int length); 146: 147: /** 148: * Update this MAC with the remaining bytes of a buffer. 149: * 150: * @param buffer The input buffer. 151: * @since 1.5 152: */ 153: protected void engineUpdate (final ByteBuffer buffer) 154: { 155: byte[] buf = new byte[1024]; 156: while (buffer.hasRemaining ()) 157: { 158: int n = Math.min (buffer.remaining (), buf.length); 159: buffer.get (buf, 0, n); 160: engineUpdate (buf, 0, n); 161: } 162: } 163: }