1/* 2 * Copyright (c) 1997, 2007, 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 26package com.sun.crypto.provider; 27 28import javax.crypto.ShortBufferException; 29 30/** 31 * Padding interface. 32 * 33 * This interface is implemented by general-purpose padding schemes, such as 34 * the one described in PKCS#5. 35 * 36 * @author Jan Luehe 37 * @author Gigi Ankeny 38 * 39 * 40 * @see PKCS5Padding 41 */ 42 43interface Padding { 44 45 /** 46 * Adds the given number of padding bytes to the data input. 47 * The value of the padding bytes is determined 48 * by the specific padding mechanism that implements this 49 * interface. 50 * 51 * @param in the input buffer with the data to pad 52 * @param the offset in <code>in</code> where the padding bytes 53 * are appended 54 * @param len the number of padding bytes to add 55 * 56 * @exception ShortBufferException if <code>in</code> is too small to hold 57 * the padding bytes 58 */ 59 void padWithLen(byte[] in, int off, int len) throws ShortBufferException; 60 61 /** 62 * Returns the index where padding starts. 63 * 64 * <p>Given a buffer with data and their padding, this method returns the 65 * index where the padding starts. 66 * 67 * @param in the buffer with the data and their padding 68 * @param off the offset in <code>in</code> where the data starts 69 * @param len the length of the data and their padding 70 * 71 * @return the index where the padding starts, or -1 if the input is 72 * not properly padded 73 */ 74 int unpad(byte[] in, int off, int len); 75 76 /** 77 * Determines how long the padding will be for a given input length. 78 * 79 * @param len the length of the data to pad 80 * 81 * @return the length of the padding 82 */ 83 int padLength(int len); 84} 85