mirror of git://gcc.gnu.org/git/gcc.git
148 lines
4.1 KiB
Java
148 lines
4.1 KiB
Java
/* DigestOutputStream.java --- An output stream tied to a message digest
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Copyright (C) 1999 Free Software Foundation, Inc.
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This file is part of GNU Classpath.
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GNU Classpath is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2, or (at your option)
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any later version.
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GNU Classpath is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with GNU Classpath; see the file COPYING. If not, write to the
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Free Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA.
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As a special exception, if you link this library with other files to
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produce an executable, this library does not by itself cause the
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resulting executable to be covered by the GNU General Public License.
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This exception does not however invalidate any other reasons why the
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executable file might be covered by the GNU General Public License. */
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package java.security;
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import java.io.OutputStream;
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import java.io.FilterOutputStream;
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import java.io.IOException;
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/**
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DigestOutputStream is a class that ties an OutputStream with a
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MessageDigest. The Message Digest is used by the class to update it
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self as bytes are written to the OutputStream.
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The updating to the digest depends on the on flag which is set to
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true by default that tells the class to update the data in the
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message digest.
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@version 0.0
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@author Mark Benvenuto <ivymccough@worldnet.att.net>
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*/
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public class DigestOutputStream extends FilterOutputStream
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{
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/**
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The message digest for the DigestOutputStream
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*/
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protected MessageDigest digest;
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//Manages the on flag
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private boolean state = true;
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/**
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Constructs a new DigestOutputStream. It associates a
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MessageDigest with the stream to compute the stream as data is
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written.
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@param stream An OutputStream to associate this stream with
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@param digest A MessageDigest to hash the stream with
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*/
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public DigestOutputStream (OutputStream stream, MessageDigest digest)
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{
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super (stream);
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this.digest = digest;
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}
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/**
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Returns the MessageDigest associated with this DigestOutputStream
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@return The MessageDigest used to hash this stream
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*/
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public MessageDigest getMessageDigest ()
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{
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return digest;
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}
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/**
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Sets the current MessageDigest to current parameter
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@param digest A MessageDigest to associate with this stream
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*/
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public void setMessageDigest (MessageDigest digest)
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{
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this.digest = digest;
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}
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/**
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Updates the hash if the on flag is true and then writes a byte to
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the underlying output stream.
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@param b A byte to write to the output stream
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@exception IOException if the underlying output stream
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cannot write the byte, this is thrown.
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*/
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public void write (int b) throws IOException
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{
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if (state)
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digest.update ((byte)b);
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super.write (b);
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}
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/**
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Updates the hash if the on flag is true and then writes the bytes
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to the underlying output stream.
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@param b Bytes to write to the output stream
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@param off Offset to start to start at in array
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@param len Length of data to write
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@exception IOException if the underlying output stream
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cannot write the bytes, this is thrown.
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*/
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public void write (byte[] b, int off, int len) throws IOException
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{
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if (state)
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digest.update (b, off, len);
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super.write (b, off, len);
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}
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/**
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Sets the flag specifying if this DigestOutputStream updates the
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digest in the write() methods. The default is on;
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@param on True means it digests stream, false means it does not
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*/
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public void on (boolean on)
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{
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state = on;
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}
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/**
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Converts the output stream and underlying message digest to a string.
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@return A string representing the output stream and message digest.
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*/
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public String toString()
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{
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return "[Digest Output Stream] " + digest.toString();
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}
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}
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