/* * Copyright (c) 2003, 2005, 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. */ /* ******************************************************************************* * (C) Copyright IBM Corp. 1996-2005 - All Rights Reserved * * * * The original version of this source code and documentation is copyrighted * * and owned by IBM, These materials are provided under terms of a License * * Agreement between IBM and Sun. This technology is protected by multiple * * US and International patents. This notice and attribution to IBM may not * * to removed. * ******************************************************************************* */ package sun.text.normalizer; import java.io.InputStream; import java.io.DataInputStream; import java.io.IOException; import java.util.Arrays; public final class ICUBinary { // public inner interface ------------------------------------------------ /** * Special interface for data authentication */ public static interface Authenticate { /** * Method used in ICUBinary.readHeader() to provide data format * authentication. * @param version version of the current data * @return true if dataformat is an acceptable version, false otherwise */ public boolean isDataVersionAcceptable(byte version[]); } // public methods -------------------------------------------------------- /** *

ICU data header reader method. * Takes a ICU generated big-endian input stream, parse the ICU standard * file header and authenticates them.

*

Header format: *

*

*

* Example of use:
*

    * try {
    *    FileInputStream input = new FileInputStream(filename);
    *    If (Utility.readICUDataHeader(input, dataformat, dataversion,
    *                                  unicode) {
    *        System.out.println("Verified file header, this is a ICU data file");
    *    }
    * } catch (IOException e) {
    *    System.out.println("This is not a ICU data file");
    * }
    * 
*

* @param inputStream input stream that contains the ICU data header * @param dataFormatIDExpected Data format expected. An array of 4 bytes * information about the data format. * E.g. data format ID 1.2.3.4. will became an array of * {1, 2, 3, 4} * @param authenticate user defined extra data authentication. This value * can be null, if no extra authentication is needed. * @exception IOException thrown if there is a read error or * when header authentication fails. * @draft 2.1 */ public static final byte[] readHeader(InputStream inputStream, byte dataFormatIDExpected[], Authenticate authenticate) throws IOException { DataInputStream input = new DataInputStream(inputStream); char headersize = input.readChar(); int readcount = 2; //reading the header format byte magic1 = input.readByte(); readcount ++; byte magic2 = input.readByte(); readcount ++; if (magic1 != MAGIC1 || magic2 != MAGIC2) { throw new IOException(MAGIC_NUMBER_AUTHENTICATION_FAILED_); } input.readChar(); // reading size readcount += 2; input.readChar(); // reading reserved word readcount += 2; byte bigendian = input.readByte(); readcount ++; byte charset = input.readByte(); readcount ++; byte charsize = input.readByte(); readcount ++; input.readByte(); // reading reserved byte readcount ++; byte dataFormatID[] = new byte[4]; input.readFully(dataFormatID); readcount += 4; byte dataVersion[] = new byte[4]; input.readFully(dataVersion); readcount += 4; byte unicodeVersion[] = new byte[4]; input.readFully(unicodeVersion); readcount += 4; if (headersize < readcount) { throw new IOException("Internal Error: Header size error"); } input.skipBytes(headersize - readcount); if (bigendian != BIG_ENDIAN_ || charset != CHAR_SET_ || charsize != CHAR_SIZE_ || !Arrays.equals(dataFormatIDExpected, dataFormatID) || (authenticate != null && !authenticate.isDataVersionAcceptable(dataVersion))) { throw new IOException(HEADER_AUTHENTICATION_FAILED_); } return unicodeVersion; } // private variables ------------------------------------------------- /** * Magic numbers to authenticate the data file */ private static final byte MAGIC1 = (byte)0xda; private static final byte MAGIC2 = (byte)0x27; /** * File format authentication values */ private static final byte BIG_ENDIAN_ = 1; private static final byte CHAR_SET_ = 0; private static final byte CHAR_SIZE_ = 2; /** * Error messages */ private static final String MAGIC_NUMBER_AUTHENTICATION_FAILED_ = "ICU data file error: Not an ICU data file"; private static final String HEADER_AUTHENTICATION_FAILED_ = "ICU data file error: Header authentication failed, please check if you have a valid ICU data file"; }