/* * Copyright (c) 1997, 2007, 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 com.sun.crypto.provider; import javax.crypto.ShortBufferException; /** * Padding interface. * * This interface is implemented by general-purpose padding schemes, such as * the one described in PKCS#5. * * @author Jan Luehe * @author Gigi Ankeny * * * @see PKCS5Padding */ interface Padding {     /**     * Adds the given number of padding bytes to the data input.     * The value of the padding bytes is determined     * by the specific padding mechanism that implements this     * interface.     *     * @param in the input buffer with the data to pad     * @param the offset in <code>in</code> where the padding bytes     *  are appended     * @param len the number of padding bytes to add     *     * @exception ShortBufferException if <code>in</code> is too small to hold     * the padding bytes     */    void padWithLen(byte[] in, int off, int len) throws ShortBufferException;     /**     * Returns the index where padding starts.     *     * <p>Given a buffer with data and their padding, this method returns the     * index where the padding starts.     *     * @param in the buffer with the data and their padding     * @param off the offset in <code>in</code> where the data starts     * @param len the length of the data and their padding     *     * @return the index where the padding starts, or -1 if the input is     * not properly padded     */    int unpad(byte[] in, int off, int len);     /**     * Determines how long the padding will be for a given input length.     *     * @param len the length of the data to pad     *     * @return the length of the padding     */    int padLength(int len);}