RetroZilla/extensions/transformiix/source/xpath/AdditiveExpr.cpp

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 * The Original Code is TransforMiiX XSLT processor code.
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 * Contributor(s):
 *   Keith Visco <kvisco@ziplink.net> (Original Author)
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/**
 * Represents a AdditiveExpr, an binary expression that
 * performs an additive operation between it's lvalue and rvalue:
 *  +   : addition
 *  -   : subtraction
**/

#include "Expr.h"
#include "ExprResult.h"
#include "txIXPathContext.h"

/**
 * Evaluates this Expr based on the given context node and processor state
 * @param context the context node for evaluation of this Expr
 * @param ps the ContextState containing the stack information needed
 * for evaluation
 * @return the result of the evaluation
**/
nsresult
AdditiveExpr::evaluate(txIEvalContext* aContext, txAExprResult** aResult)
{
    *aResult = nsnull;

    nsRefPtr<txAExprResult> exprRes;
    nsresult rv = rightExpr->evaluate(aContext, getter_AddRefs(exprRes));
    NS_ENSURE_SUCCESS(rv, rv);

    double rightDbl = exprRes->numberValue();

    rv = leftExpr->evaluate(aContext, getter_AddRefs(exprRes));
    NS_ENSURE_SUCCESS(rv, rv);

    double leftDbl = exprRes->numberValue();

    double result = 0;
    switch ( op ) {
        case SUBTRACTION:
            result = leftDbl - rightDbl;
            break;
        default:
            result = leftDbl + rightDbl;
            break;
    }

    return aContext->recycler()->getNumberResult(result, aResult);
} //-- evaluate

#ifdef TX_TO_STRING
void
AdditiveExpr::toString(nsAString& str)
{
    if ( leftExpr ) leftExpr->toString(str);
    else str.AppendLiteral("null");

    switch ( op ) {
        case SUBTRACTION:
            str.AppendLiteral(" - ");
            break;
        default:
            str.AppendLiteral(" + ");
            break;
    }
    if ( rightExpr ) rightExpr->toString(str);
    else str.AppendLiteral("null");

}
#endif