NumericExpr.cs

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using System.Xml;
using System.Xml.XPath;
using System.Xml.Xsl;
 
namespace MS.Internal.Xml.XPath;
 
internal sealed class NumericExpr : ValueQuery
{
    private readonly Operator.Op _op;
 
    private readonly Query _opnd1;
 
    private readonly Query _opnd2;
 
    public override XPathResultType StaticType => XPathResultType.Number;
 
    public NumericExpr(Operator.Op op, Query opnd1, Query opnd2)
    {
        if (opnd1.StaticType != 0)
        {
            opnd1 = new NumberFunctions(Function.FunctionType.FuncNumber, opnd1);
        }
        if (opnd2.StaticType != 0)
        {
            opnd2 = new NumberFunctions(Function.FunctionType.FuncNumber, opnd2);
        }
        _op = op;
        _opnd1 = opnd1;
        _opnd2 = opnd2;
    }
 
    private NumericExpr(NumericExpr other)
        : base(other)
    {
        _op = other._op;
        _opnd1 = Query.Clone(other._opnd1);
        _opnd2 = Query.Clone(other._opnd2);
    }
 
    public override void SetXsltContext(XsltContext context)
    {
        _opnd1.SetXsltContext(context);
        _opnd2.SetXsltContext(context);
    }
 
    public override object Evaluate(XPathNodeIterator nodeIterator)
    {
        return GetValue(_op, XmlConvert.ToXPathDouble(_opnd1.Evaluate(nodeIterator)), XmlConvert.ToXPathDouble(_opnd2.Evaluate(nodeIterator)));
    }
 
    private static double GetValue(Operator.Op op, double n1, double n2)
    {
        return op switch
        {
            Operator.Op.PLUS => n1 + n2, 
            Operator.Op.MINUS => n1 - n2, 
            Operator.Op.MOD => n1 % n2, 
            Operator.Op.DIV => n1 / n2, 
            Operator.Op.MUL => n1 * n2, 
            _ => 0.0, 
        };
    }
 
    public override XPathNodeIterator Clone()
    {
        return new NumericExpr(this);
    }
}