/*
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* Licensed to the Apache Software Foundation (ASF) Under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for Additional information regarding copyright ownership.
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* The ASF licenses this file to You Under the Apache License, Version 2.0
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* (the "License"); you may not use this file except in compliance with
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* the License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed Under the License is distributed on an "AS Is" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations Under the License.
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*/
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namespace HH.WMS.Utils.NPOI.SS.Formula.Functions
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{
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using System;
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using HH.WMS.Utils.NPOI.SS.Formula.Eval;
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/// <summary>
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/// An implementation of the MID function
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/// MID returns a specific number of
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/// Chars from a text string, starting at the specified position.
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/// @author Manda Wilson < wilson at c bio dot msk cc dot org;
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/// </summary>
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public class Mid : TextFunction
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{
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public override ValueEval EvaluateFunc(ValueEval[] args, int srcCellRow, int srcCellCol)
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{
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if (args.Length != 3)
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{
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return ErrorEval.VALUE_INVALID;
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}
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String text = EvaluateStringArg(args[0], srcCellRow, srcCellCol);
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int startCharNum = EvaluateIntArg(args[1], srcCellRow, srcCellCol);
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int numChars = EvaluateIntArg(args[2], srcCellRow, srcCellCol);
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int startIx = startCharNum - 1; // convert to zero-based
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// Note - for start_num arg, blank/zero causes error(#VALUE!),
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// but for num_chars causes empty string to be returned.
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if (startIx < 0)
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{
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return ErrorEval.VALUE_INVALID;
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}
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if (numChars < 0)
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{
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return ErrorEval.VALUE_INVALID;
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}
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int len = text.Length;
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if (numChars < 0 || startIx > len)
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{
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return new StringEval("");
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}
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int endIx = Math.Min(startIx + numChars, len);
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String result = text.Substring(startIx, endIx-startIx);
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return new StringEval(result);
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}
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}
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}
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