| /* ==================================================================== |
| 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 |
| the License. You may obtain a copy of the License at |
| |
| 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, |
| WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| See the License for the specific language governing permissions and |
| limitations under the License. |
| ==================================================================== */ |
| package org.apache.poi.ss.formula.functions; |
| |
| /** |
| * Some utils for converting from and to any base |
| */ |
| public class BaseNumberUtils { |
| |
| |
| public static double convertToDecimal(String value, int base, int maxNumberOfPlaces) throws IllegalArgumentException { |
| if (value == null || value.length() == 0) { |
| return 0.0; |
| } |
| |
| long stringLength = value.length(); |
| if (stringLength > maxNumberOfPlaces) { |
| throw new IllegalArgumentException(); |
| } |
| |
| double decimalValue = 0.0; |
| |
| long signedDigit = 0; |
| boolean hasSignedDigit = true; |
| char[] characters = value.toCharArray(); |
| for (char character : characters) { |
| long digit; |
| |
| if ('0' <= character && character <= '9') { |
| digit = (long)character - '0'; |
| } else if ('A' <= character && character <= 'Z') { |
| digit = 10L + (character - 'A'); |
| } else if ('a' <= character && character <= 'z') { |
| digit = 10L + (character - 'a'); |
| } else { |
| digit = base; |
| } |
| |
| if (digit < base) { |
| if (hasSignedDigit) { |
| hasSignedDigit = false; |
| signedDigit = digit; |
| } |
| decimalValue = decimalValue * base + digit; |
| } else { |
| throw new IllegalArgumentException("character not allowed"); |
| } |
| } |
| |
| boolean isNegative = (!hasSignedDigit && stringLength == maxNumberOfPlaces && (signedDigit >= base / 2)); |
| if (isNegative) { |
| decimalValue = getTwoComplement(base, maxNumberOfPlaces, decimalValue); |
| decimalValue = decimalValue * -1.0; |
| } |
| |
| return decimalValue; |
| } |
| |
| private static double getTwoComplement(double base, double maxNumberOfPlaces, double decimalValue) { |
| return (Math.pow(base, maxNumberOfPlaces) - decimalValue); |
| } |
| } |