185 lines
6.4 KiB
Java
185 lines
6.4 KiB
Java
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/* ====================================================================
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* The Apache Software License, Version 1.1
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*
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* Copyright (c) 2000 The Apache Software Foundation. All rights
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* reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. The end-user documentation included with the redistribution,
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* if any, must include the following acknowledgment:
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* "This product includes software developed by the
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* Apache Software Foundation (http://www.apache.org/)."
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* Alternately, this acknowledgment may appear in the software itself,
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* if and wherever such third-party acknowledgments normally appear.
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*
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* 4. The names "Apache" and "Apache Software Foundation" must
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* not be used to endorse or promote products derived from this
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* software without prior written permission. For written
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* permission, please contact apache@apache.org.
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*
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* 5. Products derived from this software may not be called "Apache",
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* nor may "Apache" appear in their name, without prior written
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* permission of the Apache Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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* USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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* ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
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* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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* ====================================================================
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*
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* This software consists of voluntary contributions made by many
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* individuals on behalf of the Apache Software Foundation. For more
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* information on the Apache Software Foundation, please see
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* <http://www.apache.org/>.
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*/
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package org.apache.poi.hpsf;
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import java.util.*;
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/**
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* <p>Provides various static utility methods.</p>
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*
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* @author Rainer Klute (klute@rainer-klute.de)
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* @version $Id$
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* @since 2002-02-09
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*/
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public class Util
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{
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/**
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* <p>Checks whether two byte arrays <var>a</var> and <var>b</var>
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* are equal. They are equal</p>
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*
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* <ul>
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* <li><p>if they have the same length and</p></li>
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*
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* <li><p>if for each <var>i</var> with
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* <var>i</var> >= 0 and
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* <var>i</var> < <var>a.length</var> holds
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* <var>a</var>[<var>i</var>] == <var>b</var>[<var>i</var>].</p></li>
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* </ul>
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*/
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public static boolean equal(final byte[] a, final byte[] b)
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{
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if (a.length != b.length)
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return false;
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for (int i = 0; i < a.length; i++)
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if (a[i] != b[i])
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return false;
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return true;
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}
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/**
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* <p>Copies a part of a byte array into another byte array.</p>
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*/
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public static void copy(final byte[] src, final int srcOffset,
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final int length,
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final byte[] dst, final int dstOffset)
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{
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for (int i = 0; i < length; i++)
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dst[dstOffset + i] = src[srcOffset + i];
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}
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/**
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* <p>Concatenates the contents of several byte arrays into a
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* single one.</p>
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*
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* @param byteArrays The byte arrays to be concatened.
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*
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* @return A new byte array containing the concatenated byte
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* arrays.
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*/
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public static byte[] cat(final byte[][] byteArrays)
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{
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int capacity = 0;
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for (int i = 0; i < byteArrays.length; i++)
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capacity += byteArrays[i].length;
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final byte[] result = new byte[capacity];
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int r = 0;
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for (int i = 0; i < byteArrays.length; i++)
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for (int j = 0; j < byteArrays[i].length; j++)
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result[r++] = byteArrays[i][j];
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return result;
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}
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/**
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* <p>Copies bytes from a source byte array into a new byte
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* array.</p>
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*
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* @param src Copy from this byte array.
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*
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* @param offset Start copying here.
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*
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* @param length Copy this many bytes.
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*
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* @return The new byte array. Its length is number of copied bytes.
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*/
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public static byte[] copy(final byte[] src, final int offset,
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final int length)
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{
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final byte[] result = new byte[length];
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copy(src, offset, length, result, 0);
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return result;
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}
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/**
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* <p>The difference between the Windows epoch (1601-01-01
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* 00:00:00) and the Unix epoch (1970-01-01 00:00:00) in
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* milliseconds: 11644473600000L. (Use your favorite spreadsheet
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* program to verify the correctness of this value. By the way,
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* did you notice that you can tell from the epochs which
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* operating system is the modern one? :-))</p>
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*/
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public final static long EPOCH_DIFF = 11644473600000L;
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/**
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* <p>Converts a Windows FILETIME into a {@link Date}. The Windows
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* FILETIME structure holds a date and time associated with a
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* file. The structure identifies a 64-bit integer specifying the
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* number of 100-nanosecond intervals which have passed since
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* January 1, 1601. This 64-bit value is split into the two double
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* word stored in the structure.</p>
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*
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* @param high The higher double word of the FILETIME structure.
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*
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* @param low The lower double word of the FILETIME structure.
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*/
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public static Date filetimeToDate(final int high, final int low)
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{
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final long filetime = ((long) high) << 32 | ((long) low);
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final long ms_since_16010101 = filetime / (1000 * 10);
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final long ms_since_19700101 = ms_since_16010101 - EPOCH_DIFF;
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return new Date(ms_since_19700101);
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}
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}
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