src/org/apache/xalan/xsltc/compiler/util/BooleanType.java

/*
 * @(#)$Id$
 *
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 2001 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xalan" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 2001, Sun
 * Microsystems., http://www.sun.com.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 *
 * @author Jacek Ambroziak
 * @author Santiago Pericas-Geertsen
 *
 */

package org.apache.xalan.xsltc.compiler.util;

import org.apache.xalan.xsltc.compiler.util.Type;
import de.fub.bytecode.generic.*;
import org.apache.xalan.xsltc.compiler.Parser;

public final class BooleanType extends Type {
    protected BooleanType() {}

    public String toString() {
	return "boolean";
    }

    public boolean identicalTo(Type other) {
	return this == other;
    }

    public String toSignature() {
	return "Z";
    }

    public boolean isSimple() {
	return true;
    }

    public de.fub.bytecode.generic.Type toJCType() {
	return de.fub.bytecode.generic.Type.BOOLEAN;
    }

    /**
     * Translates a real into an object of internal type <code>type</code>. The
     * translation to int is undefined since booleans are always converted to
     * reals in arithmetic expressions.
     *
     * @see	org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
			    Type type) {
	if (type == Type.String) {
	    translateTo(classGen, methodGen, (StringType) type);
	}
	else if (type == Type.Real) {
	    translateTo(classGen, methodGen, (RealType) type);
	}
	else if (type == Type.Reference) {
	    translateTo(classGen, methodGen, (ReferenceType) type);
	}
	else {
	    classGen.getParser().internalError(); // undefined
	}
    }

    /**
     * Expects a boolean on the stack and pushes a string. If the value on the
     * stack is zero, then the string 'false' is pushed. Otherwise, the string
     * 'true' is pushed.
     *
     * @see	org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
			    StringType type) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();
	final BranchHandle falsec = il.append(new IFEQ(null));
	il.append(new PUSH(cpg, "true"));
	final BranchHandle truec = il.append(new GOTO(null));
	falsec.setTarget(il.append(new PUSH(cpg, "false")));
	truec.setTarget(il.append(NOP));
    }

    /**
     * Expects a boolean on the stack and pushes a real. The value "true" is
     * converted to 1.0 and the value "false" to 0.0.
     *
     * @see	org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
			    RealType type) {
	methodGen.getInstructionList().append(I2D);
    }

    /**
     * Expects a boolean on the stack and pushes a boxed boolean.
     * Boxed booleans are represented by an instance of
     * <code>java.lang.Boolean</code>.
     *
     * @see	org.apache.xalan.xsltc.compiler.util.Type#translateTo
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
			    ReferenceType type) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();
	il.append(new NEW(cpg.addClass(BOOLEAN_CLASS)));
	il.append(DUP_X1);
	il.append(SWAP);
	il.append(new INVOKESPECIAL(cpg.addMethodref(BOOLEAN_CLASS,
						     "<init>",
						     "(Z)V")));
    }

    /**
     * Translates an internal boolean into an external (Java) boolean.
     */
    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen, 
			    Class clazz) {
	if (clazz == java.lang.Boolean.TYPE) {
	    methodGen.getInstructionList().append(NOP);
	}
	else {
	    classGen.getParser().internalError(); // undefined
	}
    }

    /**
     * Translates an external (Java) boolean into internal boolean.
     */
    public void translateFrom(ClassGenerator classGen, MethodGenerator methodGen, 
			      Class clazz) {
	translateTo(classGen, methodGen, clazz);
    }

    /**
     * Translates an object of this type to its boxed representation.
     */ 
    public void translateBox(ClassGenerator classGen,
			     MethodGenerator methodGen) {
	translateTo(classGen, methodGen, Type.Reference);
    }

    /**
     * Translates an object of this type to its unboxed representation.
     */ 
    public void translateUnBox(ClassGenerator classGen,
			       MethodGenerator methodGen) {
	final ConstantPoolGen cpg = classGen.getConstantPool();
	final InstructionList il = methodGen.getInstructionList();
	il.append(new CHECKCAST(cpg.addClass(BOOLEAN_CLASS)));
	il.append(new INVOKEVIRTUAL(cpg.addMethodref(BOOLEAN_CLASS,
						     BOOLEAN_VALUE, 
						     BOOLEAN_VALUE_SIG)));
    }

    public Instruction LOAD(int slot) {
	return new ILOAD(slot);
    }
	
    public Instruction STORE(int slot) {
	return new ISTORE(slot);
    }

    public BranchInstruction GT(boolean tozero) {
	return tozero ? (BranchInstruction) new IFGT(null) : 
	    (BranchInstruction) new IF_ICMPGT(null);
    }

    public BranchInstruction GE(boolean tozero) {
	return tozero ? (BranchInstruction) new IFGE(null) : 
	    (BranchInstruction) new IF_ICMPGE(null);
    }

    public BranchInstruction LT(boolean tozero) {
	return tozero ? (BranchInstruction) new IFLT(null) : 
	    (BranchInstruction) new IF_ICMPLT(null);
    }

    public BranchInstruction LE(boolean tozero) {
	return tozero ? (BranchInstruction) new IFLE(null) : 
	    (BranchInstruction) new IF_ICMPLE(null);
    }
}