103 lines
3.4 KiB
Java
103 lines
3.4 KiB
Java
/*
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* Copyright (c) 2000, 2005, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License version 2 only, as
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* published by the Free Software Foundation. Oracle designates this
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* particular file as subject to the "Classpath" exception as provided
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* by Oracle in the LICENSE file that accompanied this code.
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*
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* This code is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* version 2 for more details (a copy is included in the LICENSE file that
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* accompanied this code).
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*
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* You should have received a copy of the GNU General Public License version
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* 2 along with this work; if not, write to the Free Software Foundation,
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* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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* or visit www.oracle.com if you need additional information or have any
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* questions.
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*/
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/*
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*
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* (C) Copyright IBM Corp. 1999 All Rights Reserved.
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* Copyright 1997 The Open Group Research Institute. All rights reserved.
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*/
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package sun.security.krb5.internal.util;
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import java.io.BufferedInputStream;
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import java.io.InputStream;
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import java.io.IOException;
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/**
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* This class implements a buffered input stream. It provides methods to read a chunck
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* of data from underlying data stream.
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*
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* @author Yanni Zhang
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*
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*/
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public class KrbDataInputStream extends BufferedInputStream{
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private boolean bigEndian = true;
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public void setNativeByteOrder() {
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if (java.nio.ByteOrder.nativeOrder().
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equals(java.nio.ByteOrder.BIG_ENDIAN)) {
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bigEndian = true;
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} else {
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bigEndian = false;
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}
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}
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public KrbDataInputStream(InputStream is){
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super(is);
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}
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/**
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* Reads a length value which is represented in 4 bytes from
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* this input stream. The value must be positive.
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* @return the length value represented by this byte array.
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* @throws IOException if there are not enough bytes or it represents
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* a negative value
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*/
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final public int readLength4() throws IOException {
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int len = read(4);
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if (len < 0) {
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throw new IOException("Invalid encoding");
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}
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return len;
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}
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/**
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* Reads up to the specific number of bytes from this input stream.
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* @param num the number of bytes to be read.
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* @return the int value of this byte array.
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* @throws IOException if there are not enough bytes
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*/
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public int read(int num) throws IOException {
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byte[] bytes = new byte[num];
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if (read(bytes, 0, num) != num) {
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throw new IOException("Premature end of stream reached");
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}
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int result = 0;
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for (int i = 0; i < num; i++) {
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if (bigEndian) {
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result |= (bytes[i] & 0xff) << (num - i - 1) * 8;
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} else {
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result |= (bytes[i] & 0xff) << i * 8;
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}
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}
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return result;
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}
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public int readVersion() throws IOException {
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// always read in big-endian mode
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int result = (read() & 0xff) << 8;
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return result | (read() & 0xff);
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}
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}
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