01: /*
02: * Licensed to the Apache Software Foundation (ASF) under one or more
03: * contributor license agreements. See the NOTICE file distributed with
04: * this work for additional information regarding copyright ownership.
05: * The ASF licenses this file to You under the Apache License, Version 2.0
06: * (the "License"); you may not use this file except in compliance with
07: * the License. You may obtain a copy of the License at
08: *
09: * http://www.apache.org/licenses/LICENSE-2.0
10: *
11: * Unless required by applicable law or agreed to in writing, software
12: * distributed under the License is distributed on an "AS IS" BASIS,
13: * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14: * See the License for the specific language governing permissions and
15: * limitations under the License.
16: */
17: /*
18: * Created on May 6, 2005
19: *
20: */
21: package org.apache.poi.hssf.record.formula.functions;
22:
23: import org.apache.poi.hssf.record.formula.eval.BlankEval;
24: import org.apache.poi.hssf.record.formula.eval.ErrorEval;
25: import org.apache.poi.hssf.record.formula.eval.Eval;
26: import org.apache.poi.hssf.record.formula.eval.NumberEval;
27: import org.apache.poi.hssf.record.formula.eval.NumericValueEval;
28: import org.apache.poi.hssf.record.formula.eval.ValueEval;
29: import org.apache.poi.hssf.record.formula.eval.ValueEvalToNumericXlator;
30:
31: /**
32: * @author Amol S. Deshmukh < amolweb at ya hoo dot com >
33: * Log: LOG(number,[base])
34: */
35: public class Log extends NumericFunction {
36:
37: private static final double DEFAULT_BASE = 10;
38:
39: public Eval evaluate(Eval[] operands, int srcRow, short srcCol) {
40: double d = 0;
41: double base = DEFAULT_BASE;
42: double num = 0;
43: ValueEval retval = null;
44:
45: switch (operands.length) {
46: default:
47: retval = ErrorEval.VALUE_INVALID;
48: break;
49: case 2: // second arg is base
50: ValueEval ve = singleOperandEvaluate(operands[1], srcRow,
51: srcCol);
52: if (ve instanceof NumericValueEval) {
53: NumericValueEval ne = (NumericValueEval) ve;
54: base = ne.getNumberValue();
55: } else if (ve instanceof BlankEval) {
56: // do nothing
57: } else {
58: retval = ErrorEval.NUM_ERROR;
59: }
60:
61: case 1: // first arg is number
62: if (retval == null) {
63: ValueEval vev = singleOperandEvaluate(operands[0],
64: srcRow, srcCol);
65: if (vev instanceof NumericValueEval) {
66: NumericValueEval ne = (NumericValueEval) vev;
67: num = ne.getNumberValue();
68: } else if (vev instanceof BlankEval) {
69: // do nothing
70: } else {
71: retval = ErrorEval.NUM_ERROR;
72: }
73: }
74: }
75:
76: if (retval == null) {
77: d = (base == E) ? Math.log(num) : Math.log(num)
78: / Math.log(base);
79: retval = (Double.isNaN(d) || Double.isInfinite(d)) ? (ValueEval) ErrorEval.VALUE_INVALID
80: : new NumberEval(d);
81: }
82: return retval;
83: }
84:
85: }
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