| /* ==================================================================== |
| 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; |
| |
| import org.apache.poi.ss.formula.eval.ErrorEval; |
| import org.apache.poi.ss.formula.eval.EvaluationException; |
| import org.apache.poi.ss.formula.eval.NumberEval; |
| import org.apache.poi.ss.formula.eval.ValueEval; |
| |
| public class Log { |
| private static final double TEN = 10.0; |
| private static final double LOG_10_TO_BASE_e = Math.log(TEN); |
| |
| public static ValueEval evaluate(ValueEval[] args, int srcRowIndex, int srcColumnIndex) { |
| if (args.length != 1 && args.length != 2) { |
| return ErrorEval.VALUE_INVALID; |
| } |
| |
| try { |
| double d0 = NumericFunction.singleOperandEvaluate(args[0], srcRowIndex, srcColumnIndex); |
| double result; |
| if (args.length == 1) { |
| result = Math.log(d0) / LOG_10_TO_BASE_e; |
| } else { |
| double d1 = NumericFunction.singleOperandEvaluate(args[1], srcRowIndex, srcColumnIndex); |
| double logE = Math.log(d0); |
| result = (Double.compare(d1, Math.E) == 0) ? logE : (logE / Math.log(d1)); |
| } |
| NumericFunction.checkValue(result); |
| return new NumberEval(result); |
| } catch (EvaluationException e) { |
| return e.getErrorEval(); |
| } |
| } |
| } |