1 /* ==================================================================== 2 * The Apache Software License, Version 1.1 3 * 4 * Copyright (c) 2002 The Apache Software Foundation. All rights 5 * reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 14 * 2. Redistributions in binary form must reproduce the above copyright 15 * notice, this list of conditions and the following disclaimer in 16 * the documentation and/or other materials provided with the 17 * distribution. 18 * 19 * 3. The end-user documentation included with the redistribution, 20 * if any, must include the following acknowledgment: 21 * "This product includes software developed by the 22 * Apache Software Foundation (http://www.apache.org/)." 23 * Alternately, this acknowledgment may appear in the software itself, 24 * if and wherever such third-party acknowledgments normally appear. 25 * 26 * 4. The names "Apache" and "Apache Software Foundation" and 27 * "Apache POI" must not be used to endorse or promote products 28 * derived from this software without prior written permission. For 29 * written permission, please contact apache@apache.org. 30 * 31 * 5. Products derived from this software may not be called "Apache", 32 * "Apache POI", nor may "Apache" appear in their name, without 33 * prior written permission of the Apache Software Foundation. 34 * 35 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED 36 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 37 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 38 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR 39 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 40 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 41 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF 42 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 43 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 44 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 45 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 46 * SUCH DAMAGE. 47 * ==================================================================== 48 * 49 * This software consists of voluntary contributions made by many 50 * individuals on behalf of the Apache Software Foundation. For more 51 * information on the Apache Software Foundation, please see 52 * <http://www.apache.org/>. 53 */ 54 55 package org.apache.poi.hssf.util; 56 57 /** 58 * Utility class for helping convert RK numbers. 59 * 60 * @author Andrew C. Oliver (acoliver at apache dot org) 61 * @author Glen Stampoultzis (glens at apache.org) 62 * @author Rolf-Jürgen Moll 63 * 64 * @see org.apache.poi.hssf.record.MulRKRecord 65 * @see org.apache.poi.hssf.record.RKRecord 66 */ 67 public class RKUtil 68 { 69 private RKUtil() 70 { 71 } 72 73 /** 74 * Do the dirty work of decoding; made a private static method to 75 * facilitate testing the algorithm 76 */ 77 78 public static double decodeNumber(int number) 79 { 80 long raw_number = number; 81 82 // mask off the two low-order bits, 'cause they're not part of 83 // the number 84 raw_number = raw_number >> 2; 85 double rvalue = 0; 86 87 if ((number & 0x02) == 0x02) 88 { 89 // ok, it's just a plain ol' int; we can handle this 90 // trivially by casting 91 rvalue = ( double ) (raw_number); 92 } 93 else 94 { 95 96 // also trivial, but not as obvious ... left shift the 97 // bits high and use that clever static method in Double 98 // to convert the resulting bit image to a double 99 rvalue = Double.longBitsToDouble(raw_number << 34); 100 } 101 if ((number & 0x01) == 0x01) 102 { 103 104 // low-order bit says divide by 100, and so we do. Why? 105 // 'cause that's what the algorithm says. Can't fight city 106 // hall, especially if it's the city of Redmond 107 rvalue /= 100; 108 } 109 110 return rvalue; 111 } 112 113 } 114