/*
* Copyright 2001-2004 The Apache Software Foundation.
*
* Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* $Id: RelationalExpr.java,v 1.20 2004/12/15 17:35:38 jycli Exp $
*/
package org.apache.xalan.xsltc.compiler;
import org.apache.bcel.generic.BranchInstruction;
import org.apache.bcel.generic.ConstantPoolGen;
import org.apache.bcel.generic.INVOKESTATIC;
import org.apache.bcel.generic.InstructionList;
import org.apache.bcel.generic.PUSH;
import org.apache.xalan.xsltc.compiler.util.BooleanType;
import org.apache.xalan.xsltc.compiler.util.ClassGenerator;
import org.apache.xalan.xsltc.compiler.util.ErrorMsg;
import org.apache.xalan.xsltc.compiler.util.IntType;
import org.apache.xalan.xsltc.compiler.util.MethodGenerator;
import org.apache.xalan.xsltc.compiler.util.MethodType;
import org.apache.xalan.xsltc.compiler.util.NodeSetType;
import org.apache.xalan.xsltc.compiler.util.NodeType;
import org.apache.xalan.xsltc.compiler.util.RealType;
import org.apache.xalan.xsltc.compiler.util.ReferenceType;
import org.apache.xalan.xsltc.compiler.util.ResultTreeType;
import org.apache.xalan.xsltc.compiler.util.Type;
import org.apache.xalan.xsltc.compiler.util.TypeCheckError;
import org.apache.xalan.xsltc.runtime.Operators;
/**
* @author Jacek Ambroziak
* @author Santiago Pericas-Geertsen
*/
final class RelationalExpr extends Expression {
private int _op;
private Expression _left, _right;
public RelationalExpr(int op, Expression left, Expression right) {
_op = op;
(_left = left).setParent(this);
(_right = right).setParent(this);
}
public void setParser(Parser parser) {
super.setParser(parser);
_left.setParser(parser);
_right.setParser(parser);
}
/**
* Returns true if this expressions contains a call to position(). This is
* needed for context changes in node steps containing multiple predicates.
*/
public boolean hasPositionCall() {
if (_left.hasPositionCall()) return true;
if (_right.hasPositionCall()) return true;
return false;
}
/**
* Returns true if this expressions contains a call to last()
*/
public boolean hasLastCall() {
return (_left.hasLastCall() || _right.hasLastCall());
}
public boolean hasReferenceArgs() {
return _left.getType() instanceof ReferenceType ||
_right.getType() instanceof ReferenceType;
}
public boolean hasNodeArgs() {
return _left.getType() instanceof NodeType ||
_right.getType() instanceof NodeType;
}
public boolean hasNodeSetArgs() {
return _left.getType() instanceof NodeSetType ||
_right.getType() instanceof NodeSetType;
}
public Type typeCheck(SymbolTable stable) throws TypeCheckError {
Type tleft = _left.typeCheck(stable);
Type tright = _right.typeCheck(stable);
//bug fix # 2838, cast to reals if both are result tree fragments
if (tleft instanceof ResultTreeType &&
tright instanceof ResultTreeType )
{
_right = new CastExpr(_right, Type.Real);
_left = new CastExpr(_left, Type.Real);
return _type = Type.Boolean;
}
// If one is of reference type, then convert the other too
if (hasReferenceArgs()) {
Type type = null;
Type typeL = null;
Type typeR = null;
if (tleft instanceof ReferenceType) {
if (_left instanceof VariableRefBase) {
VariableRefBase ref = (VariableRefBase)_left;
VariableBase var = ref.getVariable();
typeL = var.getType();
}
}
if (tright instanceof ReferenceType) {
if (_right instanceof VariableRefBase) {
VariableRefBase ref = (VariableRefBase)_right;
VariableBase var = ref.getVariable();
typeR = var.getType();
}
}
// bug fix # 2838
if (typeL == null)
type = typeR;
else if (typeR == null)
type = typeL;
else {
type = Type.Real;
}
if (type == null) type = Type.Real;
_right = new CastExpr(_right, type);
_left = new CastExpr(_left, type);
return _type = Type.Boolean;
}
if (hasNodeSetArgs()) {
// Ensure that the node-set is the left argument
if (tright instanceof NodeSetType) {
final Expression temp = _right; _right = _left; _left = temp;
_op = (_op == Operators.GT) ? Operators.LT :
(_op == Operators.LT) ? Operators.GT :
(_op == Operators.GE) ? Operators.LE : Operators.GE;
tright = _right.getType();
}
// Promote nodes to node sets
if (tright instanceof NodeType) {
_right = new CastExpr(_right, Type.NodeSet);
}
// Promote integer to doubles to have fewer compares
if (tright instanceof IntType) {
_right = new CastExpr(_right, Type.Real);
}
// Promote result-trees to strings
if (tright instanceof ResultTreeType) {
_right = new CastExpr(_right, Type.String);
}
return _type = Type.Boolean;
}
// In the node-boolean case, convert node to boolean first
if (hasNodeArgs()) {
if (tleft instanceof BooleanType) {
_right = new CastExpr(_right, Type.Boolean);
tright = Type.Boolean;
}
if (tright instanceof BooleanType) {
_left = new CastExpr(_left, Type.Boolean);
tleft = Type.Boolean;
}
}
// Lookup the table of primops to find the best match
MethodType ptype = lookupPrimop(stable, Operators.getOpNames(_op),
new MethodType(Type.Void, tleft, tright));
if (ptype != null) {
Type arg1 = (Type) ptype.argsType().elementAt(0);
if (!arg1.identicalTo(tleft)) {
_left = new CastExpr(_left, arg1);
}
Type arg2 = (Type) ptype.argsType().elementAt(1);
if (!arg2.identicalTo(tright)) {
_right = new CastExpr(_right, arg1);
}
return _type = ptype.resultType();
}
throw new TypeCheckError(this);
}
public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
if (hasNodeSetArgs() || hasReferenceArgs()) {
final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
// Call compare() from the BasisLibrary
_left.translate(classGen, methodGen);
_left.startIterator(classGen, methodGen);
_right.translate(classGen, methodGen);
_right.startIterator(classGen, methodGen);
il.append(new PUSH(cpg, _op));
il.append(methodGen.loadDOM());
int index = cpg.addMethodref(BASIS_LIBRARY_CLASS, "compare",
"("
+ _left.getType().toSignature()
+ _right.getType().toSignature()
+ "I"
+ DOM_INTF_SIG
+ ")Z");
il.append(new INVOKESTATIC(index));
}
else {
translateDesynthesized(classGen, methodGen);
synthesize(classGen, methodGen);
}
}
public void translateDesynthesized(ClassGenerator classGen,
MethodGenerator methodGen) {
if (hasNodeSetArgs() || hasReferenceArgs()) {
translate(classGen, methodGen);
desynthesize(classGen, methodGen);
}
else {
BranchInstruction bi = null;
final InstructionList il = methodGen.getInstructionList();
_left.translate(classGen, methodGen);
_right.translate(classGen, methodGen);
// TODO: optimize if one of the args is 0
boolean tozero = false;
Type tleft = _left.getType();
if (tleft instanceof RealType) {
il.append(tleft.CMP(_op == Operators.LT || _op == Operators.LE));
tleft = Type.Int;
tozero = true;
}
switch (_op) {
case Operators.LT:
bi = tleft.GE(tozero);
break;
case Operators.GT:
bi = tleft.LE(tozero);
break;
case Operators.LE:
bi = tleft.GT(tozero);
break;
case Operators.GE:
bi = tleft.LT(tozero);
break;
default:
ErrorMsg msg = new ErrorMsg(ErrorMsg.ILLEGAL_RELAT_OP_ERR,this);
getParser().reportError(Constants.FATAL, msg);
}
_falseList.add(il.append(bi)); // must be backpatched
}
}
public String toString() {
return Operators.getOpNames(_op) + '(' + _left + ", " + _right + ')';
}
}