src/java/org/apache/java/security/MessageDigest.java

package org.apache.java.security;

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/**
 * This interface abstracts a message digest algorithm.
 *
 * <p><b>Note:</b> even if standard Java 1.1 APIs already provide a
 * message digest implementation, this class is used on those Java
 * runtime environments (like Kaffe) where the package
 * <code>java.security</code> is highly improbable to be found.
 *
 * @author <a href="mailto:mazzocchi@mbox.systemy.it">Stefano Mazzocchi</a>
 * @version $Id$
 * @deprecated Use the java.security package.
 */
public abstract class MessageDigest
{
    /**
     * Creates the algorithm and reset its state.
     */
    public MessageDigest()
    {
        this.reset();
    }

    /**
     * Append another block to the message.
     *
     * @param block A byte[].
     */
    public void append(byte[] block)
    {
        this.append(block, 0, block.length);
    }

    /**
     * Append another block of specified length to the message.
     *
     * @param block A byte[].
     * @param length An int.
     */
    public void append(byte[] block,
                       int length)
    {
        this.append(block, 0, length);
    }

    /**
     * Append another block of specified length to the message
     * starting at the given offset.
     *
     * @param block A byte[].
     * @param offset An int.
     * @param length An int.
     */
    public abstract void append(byte[] block,
                                int offset,
                                int length);

    /**
     * Appends a message block and return its message digest.
     *
     * @param block A byte[].
     * @return A byte[].
     */
    public byte[] digest(byte[] block)
    {
        return this.digest(block, 0, block.length);
    }

    /**
     * Appends a message block with specified length and return its
     * message digest.
     *
     * @param block A byte[].
     * @param length An int.
     * @return A byte[].
     */
    public byte[] digest(byte[] block,
                         int length)
    {
        return this.digest(block, 0, length);
    }

    /**
     * Appends a message block with specified length starting from the
     * given offset and return its message digest.
     *
     * @param block A byte[].
     * @param offset An int.
     * @param length An int.
     * @return A byte[].
     */
    public abstract byte[] digest(byte[] block,
                                  int offset,
                                  int length);

    /**
     * Resets the state of the class.  <b>Beware</b>: calling this
     * method erases all data previously inserted.
     */
    public abstract void reset();
}