1999-08-28 08:19:56 +00:00

134 lines
3.7 KiB
C++

/*
* (C) Copyright The MITRE Corporation 1999 All rights reserved.
*
* The contents of this file are subject to the Mozilla Public License
* Version 1.0 (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.mozilla.org/MPL/
*
* The program provided "as is" without any warranty express or
* implied, including the warranty of non-infringement and the implied
* warranties of merchantibility and fitness for a particular purpose.
* The Copyright owner will not be liable for any damages suffered by
* you as a result of using the Program. In no event will the Copyright
* owner be liable for any special, indirect or consequential damages or
* lost profits even if the Copyright owner has been advised of the
* possibility of their occurrence.
*
* Please see release.txt distributed with this file for more information.
*
*/
/**
* Represents a AdditiveExpr, an binary expression that
* performs an additive operation between it's lvalue and rvalue:<BR/>
* + : addition
* - : substraction
* @author <a href="mailto:kvisco@mitre.org">Keith Visco</a>
**/
#include "Expr.h"
/**
* Creates a new AdditiveExpr using the default operator (ADDITION)
**/
AdditiveExpr::AdditiveExpr() {
this->op = ADDITION;
this->leftExpr = 0;
this->rightExpr = 0;
} //-- AdditiveExpr
/**
* Creates a new AdditiveExpr using the given operator
**/
AdditiveExpr::AdditiveExpr(Expr* leftExpr, Expr* rightExpr, short op) {
this->op = op;
this->leftExpr = leftExpr;
this->rightExpr = rightExpr;
} //-- AdditiveExpr
AdditiveExpr::~AdditiveExpr() {
delete leftExpr;
delete rightExpr;
} //-- ~AdditiveExpr
/**
* Sets the left side of this AdditiveExpr
**/
void AdditiveExpr::setLeftExpr(Expr* leftExpr) {
this->leftExpr = leftExpr;
} //-- setLeftExpr
/**
* Sets the right side of this AdditiveExpr
**/
void AdditiveExpr::setRightExpr(Expr* rightExpr) {
this->rightExpr = rightExpr;
} //-- setRightExpr
/**
* 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
**/
ExprResult* AdditiveExpr::evaluate(Node* context, ContextState* cs) {
double rightDbl = Double::NaN;
ExprResult* exprRes = 0;
if ( rightExpr ) {
exprRes = rightExpr->evaluate(context, cs);
if ( exprRes ) rightDbl = exprRes->numberValue();
delete exprRes;
}
double leftDbl = Double::NaN;
if ( leftExpr ) {
exprRes = leftExpr->evaluate(context, cs);
if ( exprRes ) leftDbl = exprRes->numberValue();
delete exprRes;
}
double result = 0;
switch ( op ) {
case SUBTRACTION:
result = leftDbl - rightDbl;
break;
default:
result = leftDbl + rightDbl;
break;
}
return new NumberResult(result);
} //-- evaluate
/**
* Returns the String representation of this Expr.
* @param dest the String to use when creating the String
* representation. The String representation will be appended to
* any data in the destination String, to allow cascading calls to
* other #toString() methods for Expressions.
* @return the String representation of this Expr.
**/
void AdditiveExpr::toString(String& str) {
if ( leftExpr ) leftExpr->toString(str);
else str.append("null");
switch ( op ) {
case SUBTRACTION:
str.append(" - ");
break;
default:
str.append(" + ");
break;
}
if ( rightExpr ) rightExpr->toString(str);
else str.append("null");
} //-- toString