/* * Copyright (c) 2003, 2006, 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 sun.security.provider; import java.security.MessageDigestSpi;import java.security.DigestException;import java.security.ProviderException; /** * Common base message digest implementation for the Sun provider. * It implements all the JCA methods as suitable for a Java message digest * implementation of an algorithm based on a compression function (as all * commonly used algorithms are). The individual digest subclasses only need to * implement the following methods: * *  . abstract void implCompress(byte[] b, int ofs); *  . abstract void implDigest(byte[] out, int ofs); *  . abstract void implReset(); *  . public abstract Object clone(); * * See the inline documentation for details. * * @since   1.5 * @author  Andreas Sterbenz */abstract class DigestBase extends MessageDigestSpi implements Cloneable {     // one element byte array, temporary storage for update(byte)    private byte[] oneByte;     // algorithm name to use in the exception message    private final String algorithm;    // length of the message digest in bytes    private final int digestLength;     // size of the input to the compression function in bytes    private final int blockSize;    // buffer to store partial blocks, blockSize bytes large    // Subclasses should not access this array directly except possibly in their    // implDigest() method. See MD5.java as an example.    final byte[] buffer;    // offset into buffer    private int bufOfs;     // number of bytes processed so far. subclasses should not modify    // this value.    // also used as a flag to indicate reset status    // -1: need to call engineReset() before next call to update()    //  0: is already reset    long bytesProcessed;     /**     * Main constructor.     */    DigestBase(String algorithm, int digestLength, int blockSize) {        super();        this.algorithm = algorithm;        this.digestLength = digestLength;        this.blockSize = blockSize;        buffer = new byte[blockSize];    }     /**     * Constructor for cloning. Replicates common data.     */    DigestBase(DigestBase base) {        this.algorithm = base.algorithm;        this.digestLength = base.digestLength;        this.blockSize = base.blockSize;        this.buffer = base.buffer.clone();        this.bufOfs = base.bufOfs;        this.bytesProcessed = base.bytesProcessed;    }     // return digest length. See JCA doc.    protected final int engineGetDigestLength() {        return digestLength;    }     // single byte update. See JCA doc.    protected final void engineUpdate(byte b) {        if (oneByte == null) {            oneByte = new byte[1];        }        oneByte[0] = b;        engineUpdate(oneByte, 0, 1);    }     // array update. See JCA doc.    protected final void engineUpdate(byte[] b, int ofs, int len) {        if (len == 0) {            return;        }        if ((ofs < 0) || (len < 0) || (ofs > b.length - len)) {            throw new ArrayIndexOutOfBoundsException();        }        if (bytesProcessed < 0) {            engineReset();        }        bytesProcessed += len;        // if buffer is not empty, we need to fill it before proceeding        if (bufOfs != 0) {            int n = Math.min(len, blockSize - bufOfs);            System.arraycopy(b, ofs, buffer, bufOfs, n);            bufOfs += n;            ofs += n;            len -= n;            if (bufOfs >= blockSize) {                // compress completed block now                implCompress(buffer, 0);                bufOfs = 0;            }        }        // compress complete blocks        while (len >= blockSize) {            implCompress(b, ofs);            len -= blockSize;            ofs += blockSize;        }        // copy remainder to buffer        if (len > 0) {            System.arraycopy(b, ofs, buffer, 0, len);            bufOfs = len;        }    }     // reset this object. See JCA doc.    protected final void engineReset() {        if (bytesProcessed == 0) {            // already reset, ignore            return;        }        implReset();        bufOfs = 0;        bytesProcessed = 0;    }     // return the digest. See JCA doc.    protected final byte[] engineDigest() {        byte[] b = new byte[digestLength];        try {            engineDigest(b, 0, b.length);        } catch (DigestException e) {            throw (ProviderException)                new ProviderException("Internal error").initCause(e);        }        return b;    }     // return the digest in the specified array. See JCA doc.    protected final int engineDigest(byte[] out, int ofs, int len)            throws DigestException {        if (len < digestLength) {            throw new DigestException("Length must be at least "                + digestLength + " for " + algorithm + "digests");        }        if ((ofs < 0) || (len < 0) || (ofs > out.length - len)) {            throw new DigestException("Buffer too short to store digest");        }        if (bytesProcessed < 0) {            engineReset();        }        implDigest(out, ofs);        bytesProcessed = -1;        return digestLength;    }     /**     * Core compression function. Processes blockSize bytes at a time     * and updates the state of this object.     */    abstract void implCompress(byte[] b, int ofs);     /**     * Return the digest. Subclasses do not need to reset() themselves,     * DigestBase calls implReset() when necessary.     */    abstract void implDigest(byte[] out, int ofs);     /**     * Reset subclass specific state to their initial values. DigestBase     * calls this method when necessary.     */    abstract void implReset();     /**     * Clone this digest. Should be implemented as "return new MyDigest(this)".     * That constructor should first call "super(baseDigest)" and then copy     * subclass specific data.     */    public abstract Object clone();     // padding used for the MD5, and SHA-* message digests    static final byte[] padding;     static {        // we need 128 byte padding for SHA-384/512        // and an additional 8 bytes for the high 8 bytes of the 16        // byte bit counter in SHA-384/512        padding = new byte[136];        padding[0] = (byte)0x80;    } }