/*
* 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;
/**
* A plus operator expression which handles the case where we do not know the type of the first
* operand. this expression must be replaced by an expression with a known type during type
* checking
*/
public class PlusExpression extends BinaryOperExpression
{
public PlusExpression(Rule rule, ParseNode token, Expression left, Expression right)
{
super(rule, PLUS, Type.UNDEFINED, token, left, right);
}
public Type typeCheck(Type expected) throws TypeException {
// if the expected type is numeric then we know this must be an arithmetic plus
// if it is string then this could still be an arithmetic plus so we will
// have to rely on the type of the first argument to guide us
Type type1 = getOperand(0).typeCheck((expected.isNumeric() ? expected : Type.UNDEFINED));
Type type2;
if (type1.isNumeric()) {
type2 = getOperand(1).typeCheck(Type.N);
type = Type.promote(type1, type2);
} else if (type1.isString()) {
type2 = getOperand(1).typeCheck(Type.STRING);
type = Type.STRING;
} else {
throw new TypeException("PlusExpression.typeCheck : invalid argument type " + type1.getName() + getPos());
}
return type;
}
public Object interpret(HelperAdapter helper) throws ExecuteException {
Object value1 = getOperand(0).interpret(helper);
Object value2 = getOperand(1).interpret(helper);
if (type == Type.STRING) {
// we will have requested type String at type check but that
// does not guarantee that the returned objects are Stings, merely
// that they can be promoted to Strings. so we must be willing
// to convert non-String objects to Strings and also to handle null
String s1 = (value1 != null ? value1.toString() : "null");
String s2 = (value2 != null ? value2.toString() : "null");
return s1 + s2;
} else {
if (value1 instanceof Character) {
value1 = Integer.valueOf((Character)value1);
}
if (value2 instanceof Character) {
value2 = Integer.valueOf((Character)value2);
}
Number n1 = (Number)value1;
Number n2 = (Number)value2;
if (type == Type.B) {
byte b1 = n1.byteValue();
byte b2 = n2.byteValue();
byte result = (byte)(b1 + b2);
return Byte.valueOf(result);
} else if (type == Type.S) {
short s1 = n1.shortValue();
short s2 = n2.shortValue();
short result = (short)(s1 + s2);
return Short.valueOf(result);
} else if (type == Type.I) {
int i1 = n1.intValue();
int i2 = n2.intValue();
int result = (i1 + i2);
return Integer.valueOf(result);
} else if (type == Type.J) {
long l1 = n1.longValue();
long l2 = n2.longValue();
long result = (l1 + l2);
return Long.valueOf(result);
} else if (type == Type.F) {
float f1 = n1.floatValue();
float f2 = n2.floatValue();
float result = (f1 + f2);
return Float.valueOf(result);
} else if (type == Type.D) {
double d1 = n1.doubleValue();
double d2 = n2.doubleValue();
double result = (d1 + d2);
return Double.valueOf(result);
} else { // type == Type.C
char c1 = (char)n1.intValue();
char c2 = (char)n2.intValue();
char result = (char)(c1 + c2);
return Character.valueOf(result);
}
}
}
public void compile(MethodVisitor mv, CompileContext compileContext) throws CompileException
{
// make sure we are at the right source line
compileContext.notifySourceLine(line);
Expression oper0 = getOperand(0);
Expression oper1 = getOperand(1);
int currentStack = compileContext.getStackCount();
int expected = 0;
// compile and type convert each operand -- adds 2 or 4 depending upon type
oper0.compile(mv, compileContext);
compileTypeConversion(oper0.getType(), type, mv, compileContext);
oper1.compile(mv, compileContext);
compileTypeConversion(oper1.getType(), type, mv, compileContext);
if (type == Type.STRING) {
// ok, we could optimize this for the case where the left or right operand is a String plus expression
// by employing a StringBuffer but for now we will just evaluate the left and right operand and
// then call concat to join them
// add two strings leaving one string
expected = 1;
mv.visitMethodInsn(Opcodes.INVOKEVIRTUAL, "java/lang/String", "concat", "(Ljava/lang/String;)Ljava/lang/String;");
compileContext.addStackCount(-1);
} else if (type == Type.B) {
// add two bytes leaving one byte
expected = 1;
mv.visitInsn(Opcodes.IADD);
mv.visitInsn(Opcodes.I2B);
compileContext.addStackCount(-1);
} else if (type == Type.S ) {
// add two shorts leaving one short
expected = 1;
mv.visitInsn(Opcodes.IADD);
mv.visitInsn(Opcodes.I2S);
compileContext.addStackCount(-1);
} else if (type == Type.C) {
// add two chars leaving one char
expected = 1;
mv.visitInsn(Opcodes.IADD);
mv.visitInsn(Opcodes.I2C);
compileContext.addStackCount(-1);
} else if (type == Type.I) {
// add two ints leaving one int
expected = 1;
mv.visitInsn(Opcodes.IADD);
compileContext.addStackCount(-1);
} else if (type == Type.J) {
// add two longs leaving one long
expected = 2;
mv.visitInsn(Opcodes.LADD);
compileContext.addStackCount(-2);
} else if (type == Type.F) {
// add two floats leaving one float
expected = 1;
mv.visitInsn(Opcodes.FADD);
compileContext.addStackCount(-1);
} else if (type == Type.D) {
// add two doubles leaving one double
expected = 2;
mv.visitInsn(Opcodes.DADD);
compileContext.addStackCount(-2);
}
if (compileContext.getStackCount() != currentStack + expected) {
throw new CompileException("PlusExpression.compile : invalid stack height " + compileContext.getStackCount() + " expecting " + (currentStack + expected));
}
}
}