125 lines
4.7 KiB
Java
125 lines
4.7 KiB
Java
/* ====================================================================
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Licensed to the Apache Software Foundation (ASF) under one or more
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contributor license agreements. See the NOTICE file distributed with
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this work for additional information regarding copyright ownership.
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The ASF licenses this file to You under the Apache License, Version 2.0
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(the "License"); you may not use this file except in compliance with
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the License. You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==================================================================== */
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package org.apache.poi.ss.formula.functions;
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import org.apache.poi.ss.formula.OperationEvaluationContext;
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import org.apache.poi.ss.formula.eval.ErrorEval;
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import org.apache.poi.ss.formula.eval.NumberEval;
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import org.apache.poi.ss.formula.eval.OperandResolver;
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import org.apache.poi.ss.formula.eval.RefEval;
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import org.apache.poi.ss.formula.eval.ValueEval;
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/**
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* Implementation for Excel Bin2Dec() function.<p/>
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* <p/>
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* <b>Syntax</b>:<br/> <b>Bin2Dec </b>(<b>number</b>)<br/>
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* <p/>
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* Converts a binary number to decimal.
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* <p/>
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* Number is the binary number you want to convert. Number cannot contain more than 10 characters (10 bits).
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* The most significant bit of number is the sign bit. The remaining 9 bits are magnitude bits.
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* Negative numbers are represented using two's-complement notation.
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* <p/>
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* Remark
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* If number is not a valid binary number, or if number contains more than 10 characters (10 bits),
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* BIN2DEC returns the #NUM! error value.
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*
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* @author cedric dot walter @ gmail dot com
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*/
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public class Bin2Dec extends Fixed1ArgFunction implements FreeRefFunction {
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public static final FreeRefFunction instance = new Bin2Dec();
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public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval numberVE) {
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final String number;
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if (numberVE instanceof RefEval) {
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RefEval re = (RefEval) numberVE;
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number = OperandResolver.coerceValueToString(re.getInnerValueEval(re.getFirstSheetIndex()));
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} else {
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number = OperandResolver.coerceValueToString(numberVE);
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}
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if (number.length() > 10) {
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return ErrorEval.NUM_ERROR;
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}
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String unsigned;
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//If the leftmost bit is 0 -- number is positive.
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boolean isPositive;
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if (number.length() < 10) {
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unsigned = number;
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isPositive = true;
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} else {
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unsigned = number.substring(1);
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isPositive = number.startsWith("0");
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}
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String value;
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try {
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if (isPositive) {
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//bit9*2^8 + bit8*2^7 + bit7*2^6 + bit6*2^5 + bit5*2^4+ bit3*2^2+ bit2*2^1+ bit1*2^0
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int sum = getDecimalValue(unsigned);
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value = String.valueOf(sum);
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} else {
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//The leftmost bit is 1 -- this is negative number
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//Inverse bits [1-9]
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String inverted = toggleBits(unsigned);
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// Calculate decimal number
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int sum = getDecimalValue(inverted);
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//Add 1 to obtained number
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sum++;
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value = "-" + sum;
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}
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} catch (NumberFormatException e) {
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return ErrorEval.NUM_ERROR;
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}
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return new NumberEval(Long.parseLong(value));
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}
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private int getDecimalValue(String unsigned) {
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int sum = 0;
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int numBits = unsigned.length();
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int power = numBits - 1;
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for (int i = 0; i < numBits; i++) {
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int bit = Integer.parseInt(unsigned.substring(i, i + 1));
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int term = (int) (bit * Math.pow(2, power));
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sum += term;
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power--;
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}
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return sum;
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}
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private static String toggleBits(String s) {
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long i = Long.parseLong(s, 2);
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long i2 = i ^ ((1L << s.length()) - 1);
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String s2 = Long.toBinaryString(i2);
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while (s2.length() < s.length()) s2 = '0' + s2;
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return s2;
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}
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public ValueEval evaluate(ValueEval[] args, OperationEvaluationContext ec) {
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if (args.length != 1) {
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return ErrorEval.VALUE_INVALID;
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}
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return evaluate(ec.getRowIndex(), ec.getColumnIndex(), args[0]);
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}
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}
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