/*
* JBoss, Home of Professional Open Source
* Copyright 2008-10 Red Hat and individual contributors
* by the @authors tag. See the copyright.txt in the distribution for a
* full listing of individual contributors.
*
* This is free software; you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this software; if not, write to the Free
* Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
* 02110-1301 USA, or see the FSF site: http://www.fsf.org.
*
* @authors Andrew Dinn
*/
package org.jboss.byteman.rule.expression;
import org.jboss.byteman.rule.compiler.CompileContext;
import org.jboss.byteman.rule.type.Type;
import org.jboss.byteman.rule.exception.TypeException;
import org.jboss.byteman.rule.exception.ExecuteException;
import org.jboss.byteman.rule.exception.CompileException;
import org.jboss.byteman.rule.Rule;
import org.jboss.byteman.rule.helper.HelperAdapter;
import org.jboss.byteman.rule.grammar.ParseNode;
import org.objectweb.asm.MethodVisitor;
import org.objectweb.asm.Opcodes;
/**
*/
public class MinusExpression extends UnaryOperExpression
{
public MinusExpression(Rule rule, ParseNode token, Expression operand)
{
super(rule, UMINUS, operand.getType(), token, operand);
}
public Type typeCheck(Type expected)
throws TypeException {
type = getOperand(0).typeCheck(Type.N);
if (Type.dereference(expected).isDefined() && !expected.isAssignableFrom(type)) {
throw new TypeException("MinusExpression.typeCheck() : invalid result type : " + expected.getName() + getPos());
}
return type;
}
public Object interpret(HelperAdapter helper) throws ExecuteException {
try {
Object objValue = (Object)getOperand(0).interpret(helper);
Number value;
if (objValue instanceof Character) {
value = Integer.valueOf((Character)objValue);
} else {
value = (Number)objValue;
}
if (type == Type.B) {
return (byte)-value.intValue();
} else if (type == Type.S) {
return (short)-value.intValue();
} else if (type == Type.I) {
return -value.intValue();
} else if (type == Type.J) {
return -value.longValue();
} else if (type == Type.F) {
return -value.longValue();
} else if (type == Type.D) {
return -value.longValue();
} else { // (type == Type.C)
return -value.intValue();
}
} catch (ExecuteException e) {
throw e;
} catch (Exception e) {
throw new ExecuteException("MinusExpression.typeCheck() : unexpected exception : " + token.getText() + getPos(), e);
}
}
public void compile(MethodVisitor mv, CompileContext compileContext) throws CompileException
{
// make sure we are at the right source line
compileContext.notifySourceLine(line);
Expression oper = getOperand(0);
Type operType = oper.getType();
int currentStack = compileContext.getStackCount();
int expected = 0;
// compile code to execute the value then negate it
oper.compile(mv, compileContext);
compileTypeConversion(operType, type, mv, compileContext);
// ok, now negate the value
if (type == Type.B || type == Type.S || type == Type.I) {
mv.visitInsn(Opcodes.INEG);
expected = 1;
} else if (type == Type.J) {
mv.visitInsn(Opcodes.LNEG);
expected = 2;
} else if (type == Type.F) {
mv.visitInsn(Opcodes.FNEG);
expected = 1;
} else if (type == Type.D) {
mv.visitInsn(Opcodes.DNEG);
expected = 2;
}
// check stack height
if (compileContext.getStackCount() != currentStack + expected) {
throw new CompileException("MinusExpression.compile : invalid stack height " + compileContext.getStackCount() + " expecting " + currentStack + expected);
}
}
}