/* ==================================================================== | |
Licensed to the Apache Software Foundation (ASF) under one or more | |
contributor license agreements. See the NOTICE file distributed with | |
this work for additional information regarding copyright ownership. | |
The ASF licenses this file to You under the Apache License, Version 2.0 | |
(the "License"); you may not use this file except in compliance with | |
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http://www.apache.org/licenses/LICENSE-2.0 | |
Unless required by applicable law or agreed to in writing, software | |
distributed under the License is distributed on an "AS IS" BASIS, | |
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package org.apache.poi.ss.formula.functions; | |
import org.apache.poi.ss.formula.OperationEvaluationContext; | |
import org.apache.poi.ss.formula.eval.ErrorEval; | |
import org.apache.poi.ss.formula.eval.NumberEval; | |
import org.apache.poi.ss.formula.eval.OperandResolver; | |
import org.apache.poi.ss.formula.eval.RefEval; | |
import org.apache.poi.ss.formula.eval.ValueEval; | |
/** | |
* Implementation for Excel Bin2Dec() function.<p/> | |
* <p/> | |
* <b>Syntax</b>:<br/> <b>Bin2Dec </b>(<b>number</b>)<br/> | |
* <p/> | |
* Converts a binary number to decimal. | |
* <p/> | |
* Number is the binary number you want to convert. Number cannot contain more than 10 characters (10 bits). | |
* The most significant bit of number is the sign bit. The remaining 9 bits are magnitude bits. | |
* Negative numbers are represented using two's-complement notation. | |
* <p/> | |
* Remark | |
* If number is not a valid binary number, or if number contains more than 10 characters (10 bits), | |
* BIN2DEC returns the #NUM! error value. | |
* | |
* @author cedric dot walter @ gmail dot com | |
*/ | |
public class Bin2Dec extends Fixed1ArgFunction implements FreeRefFunction { | |
public static final FreeRefFunction instance = new Bin2Dec(); | |
public ValueEval evaluate(int srcRowIndex, int srcColumnIndex, ValueEval numberVE) { | |
final String number; | |
if (numberVE instanceof RefEval) { | |
RefEval re = (RefEval) numberVE; | |
number = OperandResolver.coerceValueToString(re.getInnerValueEval(re.getFirstSheetIndex())); | |
} else { | |
number = OperandResolver.coerceValueToString(numberVE); | |
} | |
if (number.length() > 10) { | |
return ErrorEval.NUM_ERROR; | |
} | |
String unsigned; | |
//If the leftmost bit is 0 -- number is positive. | |
boolean isPositive; | |
if (number.length() < 10) { | |
unsigned = number; | |
isPositive = true; | |
} else { | |
unsigned = number.substring(1); | |
isPositive = number.startsWith("0"); | |
} | |
String value; | |
try { | |
if (isPositive) { | |
//bit9*2^8 + bit8*2^7 + bit7*2^6 + bit6*2^5 + bit5*2^4+ bit3*2^2+ bit2*2^1+ bit1*2^0 | |
int sum = getDecimalValue(unsigned); | |
value = String.valueOf(sum); | |
} else { | |
//The leftmost bit is 1 -- this is negative number | |
//Inverse bits [1-9] | |
String inverted = toggleBits(unsigned); | |
// Calculate decimal number | |
int sum = getDecimalValue(inverted); | |
//Add 1 to obtained number | |
sum++; | |
value = "-" + sum; | |
} | |
} catch (NumberFormatException e) { | |
return ErrorEval.NUM_ERROR; | |
} | |
return new NumberEval(Long.parseLong(value)); | |
} | |
private int getDecimalValue(String unsigned) { | |
int sum = 0; | |
int numBits = unsigned.length(); | |
int power = numBits - 1; | |
for (int i = 0; i < numBits; i++) { | |
int bit = Integer.parseInt(unsigned.substring(i, i + 1)); | |
int term = (int) (bit * Math.pow(2, power)); | |
sum += term; | |
power--; | |
} | |
return sum; | |
} | |
private static String toggleBits(String s) { | |
long i = Long.parseLong(s, 2); | |
long i2 = i ^ ((1L << s.length()) - 1); | |
String s2 = Long.toBinaryString(i2); | |
while (s2.length() < s.length()) s2 = '0' + s2; | |
return s2; | |
} | |
public ValueEval evaluate(ValueEval[] args, OperationEvaluationContext ec) { | |
if (args.length != 1) { | |
return ErrorEval.VALUE_INVALID; | |
} | |
return evaluate(ec.getRowIndex(), ec.getColumnIndex(), args[0]); | |
} | |
} |