public override ValueEval Evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0,
ValueEval arg1)
{
String arg;
int index;
try
{
arg = TextFunction.EvaluateStringArg(arg0, srcRowIndex, srcColumnIndex);
index = TextFunction.EvaluateIntArg(arg1, srcRowIndex, srcColumnIndex);
}
catch (EvaluationException e)
{
return(e.GetErrorEval());
}
if (index < 0)
{
return(ErrorEval.VALUE_INVALID);
}
String result;
if (_isLeft)
{
result = arg.Substring(0, Math.Min(arg.Length, index));
}
else
{
result = arg.Substring(Math.Max(0, arg.Length - index));
}
return(new StringEval(result));
}
public override ValueEval Evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0)
{
int arg;
try
{
arg = TextFunction.EvaluateIntArg(arg0, srcRowIndex, srcColumnIndex);
if (arg < 0 || arg >= 256)
{
throw new EvaluationException(ErrorEval.VALUE_INVALID);
}
}
catch (EvaluationException e)
{
return(e.GetErrorEval());
}
return(new StringEval(Convert.ToString((char)arg, CultureInfo.CurrentCulture)));
}
public override ValueEval Evaluate(int srcRowIndex, int srcColumnIndex, ValueEval arg0, ValueEval arg1,
ValueEval arg2)
{
try
{
String needle = TextFunction.EvaluateStringArg(arg0, srcRowIndex, srcColumnIndex);
String haystack = TextFunction.EvaluateStringArg(arg1, srcRowIndex, srcColumnIndex);
// evaluate third arg and convert from 1-based to 0-based index
int startpos = TextFunction.EvaluateIntArg(arg2, srcRowIndex, srcColumnIndex) - 1;
if (startpos < 0)
{
return(ErrorEval.VALUE_INVALID);
}
return(Eval(haystack, needle, startpos));
}
catch (EvaluationException e)
{
return(e.GetErrorEval());
}
}