/*
* 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.hssf.record.formula.functions;
import org.apache.poi.hssf.record.formula.eval.AreaEval;
import org.apache.poi.hssf.record.formula.eval.ErrorEval;
import org.apache.poi.hssf.record.formula.eval.Eval;
import org.apache.poi.hssf.record.formula.eval.NumberEval;
import org.apache.poi.hssf.record.formula.eval.RefEval;
/**
* Implementation for the Excel function INDEX<p/>
*
* Syntax : <br/>
* INDEX ( reference, row_num[, column_num [, area_num]])</br>
* INDEX ( array, row_num[, column_num])
* <table border="0" cellpadding="1" cellspacing="0" summary="Parameter descriptions">
* <tr><th>reference</th><td>typically an area reference, possibly a union of areas</td></tr>
* <tr><th>array</th><td>a literal array value (currently not supported)</td></tr>
* <tr><th>row_num</th><td>selects the row within the array or area reference</td></tr>
* <tr><th>column_num</th><td>selects column within the array or area reference. default is 1</td></tr>
* <tr><th>area_num</th><td>used when reference is a union of areas</td></tr>
* </table>
* <p/>
*
* @author Josh Micich
*/
public final class Index implements Function {
// TODO - javadoc for interface method
public Eval evaluate(Eval[] args, int srcCellRow, short srcCellCol) {
int nArgs = args.length;
if(nArgs < 2) {
// too few arguments
return ErrorEval.VALUE_INVALID;
}
Eval firstArg = args[0];
if(firstArg instanceof AreaEval) {
AreaEval reference = (AreaEval) firstArg;
int rowIx = 0;
int columnIx = 0;
int areaIx = 0;
switch(nArgs) {
case 4:
areaIx = convertIndexArgToZeroBase(args[3]);
throw new RuntimeException("Incomplete code" +
" - don't know how to support the 'area_num' parameter yet)");
// Excel expression might look like this "INDEX( (A1:B4, C3:D6, D2:E5 ), 1, 2, 3)
// In this example, the 3rd area would be used i.e. D2:E5, and the overall result would be E2
// Token array might be encoded like this: MemAreaPtg, AreaPtg, AreaPtg, UnionPtg, UnionPtg, ParenthesesPtg
// The formula parser doesn't seem to support this yet. Not sure if the evaluator does either
case 3:
columnIx = convertIndexArgToZeroBase(args[2]);
case 2:
rowIx = convertIndexArgToZeroBase(args[1]);
break;
default:
// too many arguments
return ErrorEval.VALUE_INVALID;
}
int nColumns = reference.getLastColumn()-reference.getFirstColumn()+1;
int index = rowIx * nColumns + columnIx;
return reference.getValues()[index];
}
// else the other variation of this function takes an array as the first argument
// it seems like interface 'ArrayEval' does not even exist yet
throw new RuntimeException("Incomplete code - cannot handle first arg of type ("
+ firstArg.getClass().getName() + ")");
}
/**
* takes a NumberEval representing a 1-based index and returns the zero-based int value
*/
private static int convertIndexArgToZeroBase(Eval ev) {
NumberEval ne;
if(ev instanceof RefEval) {
// TODO - write junit to justify this
RefEval re = (RefEval) ev;
ne = (NumberEval) re.getInnerValueEval();
} else {
ne = (NumberEval)ev;
}
return (int)ne.getNumberValue() - 1;
}
}