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diff --git a/libjava/classpath/gnu/java/security/hash/BaseHash.java b/libjava/classpath/gnu/java/security/hash/BaseHash.java
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+++ b/libjava/classpath/gnu/java/security/hash/BaseHash.java
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+/* BaseHash.java --
+   Copyright (C) 2001, 2002, 2006 Free Software Foundation, Inc.
+
+This file is a part of GNU Classpath.
+
+GNU Classpath is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2 of the License, or (at
+your option) any later version.
+
+GNU Classpath 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 for more details.
+
+You should have received a copy of the GNU General Public License
+along with GNU Classpath; if not, write to the Free Software
+Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
+USA
+
+Linking this library statically or dynamically with other modules is
+making a combined work based on this library.  Thus, the terms and
+conditions of the GNU General Public License cover the whole
+combination.
+
+As a special exception, the copyright holders of this library give you
+permission to link this library with independent modules to produce an
+executable, regardless of the license terms of these independent
+modules, and to copy and distribute the resulting executable under
+terms of your choice, provided that you also meet, for each linked
+independent module, the terms and conditions of the license of that
+module.  An independent module is a module which is not derived from
+or based on this library.  If you modify this library, you may extend
+this exception to your version of the library, but you are not
+obligated to do so.  If you do not wish to do so, delete this
+exception statement from your version.  */
+
+
+package gnu.java.security.hash;
+
+/**
+ * A base abstract class to facilitate hash implementations.
+ */
+public abstract class BaseHash
+    implements IMessageDigest
+{
+  /** The canonical name prefix of the hash. */
+  protected String name;
+
+  /** The hash (output) size in bytes. */
+  protected int hashSize;
+
+  /** The hash (inner) block size in bytes. */
+  protected int blockSize;
+
+  /** Number of bytes processed so far. */
+  protected long count;
+
+  /** Temporary input buffer. */
+  protected byte[] buffer;
+
+  /**
+   * Trivial constructor for use by concrete subclasses.
+   *
+   * @param name the canonical name prefix of this instance.
+   * @param hashSize the block size of the output in bytes.
+   * @param blockSize the block size of the internal transform.
+   */
+  protected BaseHash(String name, int hashSize, int blockSize)
+  {
+    super();
+
+    this.name = name;
+    this.hashSize = hashSize;
+    this.blockSize = blockSize;
+    this.buffer = new byte[blockSize];
+
+    resetContext();
+  }
+
+  public String name()
+  {
+    return name;
+  }
+
+  public int hashSize()
+  {
+    return hashSize;
+  }
+
+  public int blockSize()
+  {
+    return blockSize;
+  }
+
+  public void update(byte b)
+  {
+    // compute number of bytes still unhashed; ie. present in buffer
+    int i = (int) (count % blockSize);
+    count++;
+    buffer[i] = b;
+    if (i == (blockSize - 1))
+      transform(buffer, 0);
+  }
+
+  public void update(byte[] b)
+  {
+    update(b, 0, b.length);
+  }
+
+  public void update(byte[] b, int offset, int len)
+  {
+    int n = (int) (count % blockSize);
+    count += len;
+    int partLen = blockSize - n;
+    int i = 0;
+
+    if (len >= partLen)
+      {
+        System.arraycopy(b, offset, buffer, n, partLen);
+        transform(buffer, 0);
+        for (i = partLen; i + blockSize - 1 < len; i += blockSize)
+          transform(b, offset + i);
+
+        n = 0;
+      }
+
+    if (i < len)
+      System.arraycopy(b, offset + i, buffer, n, len - i);
+  }
+
+  public byte[] digest()
+  {
+    byte[] tail = padBuffer(); // pad remaining bytes in buffer
+    update(tail, 0, tail.length); // last transform of a message
+    byte[] result = getResult(); // make a result out of context
+
+    reset(); // reset this instance for future re-use
+
+    return result;
+  }
+
+  public void reset()
+  { // reset this instance for future re-use
+    count = 0L;
+    for (int i = 0; i < blockSize;)
+      buffer[i++] = 0;
+
+    resetContext();
+  }
+
+  public abstract Object clone();
+
+  public abstract boolean selfTest();
+
+  /**
+   * Returns the byte array to use as padding before completing a hash
+   * operation.
+   *
+   * @return the bytes to pad the remaining bytes in the buffer before
+   *         completing a hash operation.
+   */
+  protected abstract byte[] padBuffer();
+
+  /**
+   * Constructs the result from the contents of the current context.
+   *
+   * @return the output of the completed hash operation.
+   */
+  protected abstract byte[] getResult();
+
+  /** Resets the instance for future re-use. */
+  protected abstract void resetContext();
+
+  /**
+   * The block digest transformation per se.
+   *
+   * @param in the <i>blockSize</i> long block, as an array of bytes to digest.
+   * @param offset the index where the data to digest is located within the
+   *          input buffer.
+   */
+  protected abstract void transform(byte[] in, int offset);
+}