/*
* 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: EqualityExpr.java,v 1.2.4.1 2005/09/12 10:16:52 pvedula Exp $
*/
package com.sun.org.apache.xalan.internal.xsltc.compiler;
import com.sun.org.apache.bcel.internal.generic.BranchHandle;
import com.sun.org.apache.bcel.internal.generic.BranchInstruction;
import com.sun.org.apache.bcel.internal.generic.ConstantPoolGen;
import com.sun.org.apache.bcel.internal.generic.GOTO;
import com.sun.org.apache.bcel.internal.generic.IFEQ;
import com.sun.org.apache.bcel.internal.generic.IFNE;
import com.sun.org.apache.bcel.internal.generic.IF_ICMPEQ;
import com.sun.org.apache.bcel.internal.generic.IF_ICMPNE;
import com.sun.org.apache.bcel.internal.generic.INVOKESTATIC;
import com.sun.org.apache.bcel.internal.generic.INVOKEVIRTUAL;
import com.sun.org.apache.bcel.internal.generic.InstructionList;
import com.sun.org.apache.bcel.internal.generic.PUSH;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.BooleanType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ClassGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.IntType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.MethodGenerator;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeSetType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NodeType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.NumberType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.RealType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ReferenceType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.ResultTreeType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.StringType;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type;
import com.sun.org.apache.xalan.internal.xsltc.compiler.util.TypeCheckError;
import com.sun.org.apache.xalan.internal.xsltc.runtime.Operators;
/**
* @author Jacek Ambroziak
* @author Santiago Pericas-Geertsen
* @author Morten Jorgensen
* @author Erwin Bolwidt <ejb@klomp.org>
*/
final class EqualityExpr extends Expression {
private final int _op;
private Expression _left;
private Expression _right;
public EqualityExpr(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);
}
public String toString() {
return Operators.getOpNames(_op) + '(' + _left + ", " + _right + ')';
}
public Expression getLeft() {
return _left;
}
public Expression getRight() {
return _right;
}
public boolean getOp() {
return (_op != Operators.NE);
}
/**
* 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;
}
public boolean hasLastCall() {
if (_left.hasLastCall()) return true;
if (_right.hasLastCall()) return true;
return false;
}
private void swapArguments() {
final Expression temp = _left;
_left = _right;
_right = temp;
}
/**
* Typing rules: see XSLT Reference by M. Kay page 345.
*/
public Type typeCheck(SymbolTable stable) throws TypeCheckError {
final Type tleft = _left.typeCheck(stable);
final Type tright = _right.typeCheck(stable);
if (tleft.isSimple() && tright.isSimple()) {
if (tleft != tright) {
if (tleft instanceof BooleanType) {
_right = new CastExpr(_right, Type.Boolean);
}
else if (tright instanceof BooleanType) {
_left = new CastExpr(_left, Type.Boolean);
}
else if (tleft instanceof NumberType ||
tright instanceof NumberType) {
_left = new CastExpr(_left, Type.Real);
_right = new CastExpr(_right, Type.Real);
}
else { // both compared as strings
_left = new CastExpr(_left, Type.String);
_right = new CastExpr(_right, Type.String);
}
}
}
else if (tleft instanceof ReferenceType) {
_right = new CastExpr(_right, Type.Reference);
}
else if (tright instanceof ReferenceType) {
_left = new CastExpr(_left, Type.Reference);
}
// the following 2 cases optimize @attr|.|.. = 'string'
else if (tleft instanceof NodeType && tright == Type.String) {
_left = new CastExpr(_left, Type.String);
}
else if (tleft == Type.String && tright instanceof NodeType) {
_right = new CastExpr(_right, Type.String);
}
// optimize node/node
else if (tleft instanceof NodeType && tright instanceof NodeType) {
_left = new CastExpr(_left, Type.String);
_right = new CastExpr(_right, Type.String);
}
else if (tleft instanceof NodeType && tright instanceof NodeSetType) {
// compare(Node, NodeSet) will be invoked
}
else if (tleft instanceof NodeSetType && tright instanceof NodeType) {
swapArguments(); // for compare(Node, NodeSet)
}
else {
// At least one argument is of type node, node-set or result-tree
// Promote an expression of type node to node-set
if (tleft instanceof NodeType) {
_left = new CastExpr(_left, Type.NodeSet);
}
if (tright instanceof NodeType) {
_right = new CastExpr(_right, Type.NodeSet);
}
// If one arg is a node-set then make it the left one
if (tleft.isSimple() ||
tleft instanceof ResultTreeType &&
tright instanceof NodeSetType) {
swapArguments();
}
// Promote integers to doubles to have fewer compares
if (_right.getType() instanceof IntType) {
_right = new CastExpr(_right, Type.Real);
}
}
return _type = Type.Boolean;
}
public void translateDesynthesized(ClassGenerator classGen,
MethodGenerator methodGen) {
final Type tleft = _left.getType();
final InstructionList il = methodGen.getInstructionList();
if (tleft instanceof BooleanType) {
_left.translate(classGen, methodGen);
_right.translate(classGen, methodGen);
_falseList.add(il.append(_op == Operators.EQ ?
(BranchInstruction)new IF_ICMPNE(null) :
(BranchInstruction)new IF_ICMPEQ(null)));
}
else if (tleft instanceof NumberType) {
_left.translate(classGen, methodGen);
_right.translate(classGen, methodGen);
if (tleft instanceof RealType) {
il.append(DCMPG);
_falseList.add(il.append(_op == Operators.EQ ?
(BranchInstruction)new IFNE(null) :
(BranchInstruction)new IFEQ(null)));
}
else {
_falseList.add(il.append(_op == Operators.EQ ?
(BranchInstruction)new IF_ICMPNE(null) :
(BranchInstruction)new IF_ICMPEQ(null)));
}
}
else {
translate(classGen, methodGen);
desynthesize(classGen, methodGen);
}
}
public void translate(ClassGenerator classGen, MethodGenerator methodGen) {
final ConstantPoolGen cpg = classGen.getConstantPool();
final InstructionList il = methodGen.getInstructionList();
final Type tleft = _left.getType();
Type tright = _right.getType();
if (tleft instanceof BooleanType || tleft instanceof NumberType) {
translateDesynthesized(classGen, methodGen);
synthesize(classGen, methodGen);
return;
}
if (tleft instanceof StringType) {
final int equals = cpg.addMethodref(STRING_CLASS,
"equals",
"(" + OBJECT_SIG +")Z");
_left.translate(classGen, methodGen);
_right.translate(classGen, methodGen);
il.append(new INVOKEVIRTUAL(equals));
if (_op == Operators.NE) {
il.append(ICONST_1);
il.append(IXOR); // not x <-> x xor 1
}
return;
}
BranchHandle truec, falsec;
if (tleft instanceof ResultTreeType) {
if (tright instanceof BooleanType) {
_right.translate(classGen, methodGen);
if (_op == Operators.NE) {
il.append(ICONST_1);
il.append(IXOR); // not x <-> x xor 1
}
return;
}
if (tright instanceof RealType) {
_left.translate(classGen, methodGen);
tleft.translateTo(classGen, methodGen, Type.Real);
_right.translate(classGen, methodGen);
il.append(DCMPG);
falsec = il.append(_op == Operators.EQ ?
(BranchInstruction) new IFNE(null) :
(BranchInstruction) new IFEQ(null));
il.append(ICONST_1);
truec = il.append(new GOTO(null));
falsec.setTarget(il.append(ICONST_0));
truec.setTarget(il.append(NOP));
return;
}
// Next, result-tree/string and result-tree/result-tree comparisons
_left.translate(classGen, methodGen);
tleft.translateTo(classGen, methodGen, Type.String);
_right.translate(classGen, methodGen);
if (tright instanceof ResultTreeType) {
tright.translateTo(classGen, methodGen, Type.String);
}
final int equals = cpg.addMethodref(STRING_CLASS,
"equals",
"(" +OBJECT_SIG+ ")Z");
il.append(new INVOKEVIRTUAL(equals));
if (_op == Operators.NE) {
il.append(ICONST_1);
il.append(IXOR); // not x <-> x xor 1
}
return;
}
if (tleft instanceof NodeSetType && tright instanceof BooleanType) {
_left.translate(classGen, methodGen);
_left.startIterator(classGen, methodGen);
Type.NodeSet.translateTo(classGen, methodGen, Type.Boolean);
_right.translate(classGen, methodGen);
il.append(IXOR); // x != y <-> x xor y
if (_op == Operators.EQ) {
il.append(ICONST_1);
il.append(IXOR); // not x <-> x xor 1
}
return;
}
if (tleft instanceof NodeSetType && tright instanceof StringType) {
_left.translate(classGen, methodGen);
_left.startIterator(classGen, methodGen); // needed ?
_right.translate(classGen, methodGen);
il.append(new PUSH(cpg, _op));
il.append(methodGen.loadDOM());
final int cmp = cpg.addMethodref(BASIS_LIBRARY_CLASS,
"compare",
"("
+ tleft.toSignature()
+ tright.toSignature()
+ "I"
+ DOM_INTF_SIG
+ ")Z");
il.append(new INVOKESTATIC(cmp));
return;
}
// Next, node-set/t for t in {real, string, node-set, result-tree}
_left.translate(classGen, methodGen);
_left.startIterator(classGen, methodGen);
_right.translate(classGen, methodGen);
_right.startIterator(classGen, methodGen);
// Cast a result tree to a string to use an existing compare
if (tright instanceof ResultTreeType) {
tright.translateTo(classGen, methodGen, Type.String);
tright = Type.String;
}
// Call the appropriate compare() from the BasisLibrary
il.append(new PUSH(cpg, _op));
il.append(methodGen.loadDOM());
final int compare = cpg.addMethodref(BASIS_LIBRARY_CLASS,
"compare",
"("
+ tleft.toSignature()
+ tright.toSignature()
+ "I"
+ DOM_INTF_SIG
+ ")Z");
il.append(new INVOKESTATIC(compare));
}
}