/*

 */

/*

 * Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You 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.

 */

package com.sun.org.apache.xalan.internal.xsltc.compiler.util;

import com.sun.org.apache.bcel.internal.generic.ALOAD;

import com.sun.org.apache.bcel.internal.generic.ASTORE;

import com.sun.org.apache.bcel.internal.generic.BranchHandle;

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.IFNONNULL;

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.Instruction;

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.Constants;

import com.sun.org.apache.xalan.internal.xsltc.compiler.FlowList;

/**

 * @author Jacek Ambroziak

 * @author Santiago Pericas-Geertsen

 */

public class StringType extends Type {

    protected StringType() {}

    public String toString() {

        return "string";

    }

    public boolean identicalTo(Type other) {

        return this == other;

    }

    public String toSignature() {

        return "Ljava/lang/String;";

    }

    public boolean isSimple() {

        return true;

    }

    public com.sun.org.apache.bcel.internal.generic.Type toJCType() {

        return com.sun.org.apache.bcel.internal.generic.Type.STRING;

    }

    /**

     * Translates a string into an object of internal type <code>type</code>.

     * The translation to int is undefined since strings are always converted

     * to reals in arithmetic expressions.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo

     */

    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,

                            Type type) {

        if (type == Type.Boolean) {

            translateTo(classGen, methodGen, (BooleanType) type);

        }

        else if (type == Type.Real) {

            translateTo(classGen, methodGen, (RealType) type);

        }

        else if (type == Type.Reference) {

            translateTo(classGen, methodGen, (ReferenceType) type);

        }

        else if (type == Type.ObjectString) {

            // NOP -> same representation

        }

        else {

            ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,

                                        toString(), type.toString());

            classGen.getParser().reportError(Constants.FATAL, err);

        }

    }

    /**

     * Translates a string into a synthesized boolean.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo

     */

    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,

                            BooleanType type) {

        final InstructionList il = methodGen.getInstructionList();

        FlowList falsel = translateToDesynthesized(classGen, methodGen, type);

        il.append(ICONST_1);

        final BranchHandle truec = il.append(new GOTO(null));

        falsel.backPatch(il.append(ICONST_0));

        truec.setTarget(il.append(NOP));

    }

    /**

     * Translates a string into a real by calling stringToReal() from the

     * basis library.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo

     */

    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,

                            RealType type) {

        final ConstantPoolGen cpg = classGen.getConstantPool();

        final InstructionList il = methodGen.getInstructionList();

        il.append(new INVOKESTATIC(cpg.addMethodref(BASIS_LIBRARY_CLASS,

                                                    STRING_TO_REAL,

                                                    STRING_TO_REAL_SIG)));

    }

    /**

     * Translates a string into a non-synthesized boolean. It does not push a

     * 0 or a 1 but instead returns branchhandle list to be appended to the

     * false list.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateToDesynthesized

     */

    public FlowList translateToDesynthesized(ClassGenerator classGen,

                                             MethodGenerator methodGen,

                                             BooleanType type) {

        final ConstantPoolGen cpg = classGen.getConstantPool();

        final InstructionList il = methodGen.getInstructionList();

        il.append(new INVOKEVIRTUAL(cpg.addMethodref(STRING_CLASS,

                                                     "length", "()I")));

        return new FlowList(il.append(new IFEQ(null)));

    }

    /**

     * Expects a string on the stack and pushes a boxed string.

     * Strings are already boxed so the translation is just a NOP.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateTo

     */

    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,

                            ReferenceType type) {

        methodGen.getInstructionList().append(NOP);

    }

    /**

     * Translates a internal string into an external (Java) string.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateFrom

     */

    public void translateTo(ClassGenerator classGen, MethodGenerator methodGen,

    {

        // Is String <: clazz? I.e. clazz in { String, Object }

        if (clazz.isAssignableFrom(java.lang.String.class)) {

            methodGen.getInstructionList().append(NOP);

        }

        else {

            ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,

                                        toString(), clazz.getName());

            classGen.getParser().reportError(Constants.FATAL, err);

        }

    }

    /**

     * Translates an external (primitive) Java type into a string.

     *

     * @see     com.sun.org.apache.xalan.internal.xsltc.compiler.util.Type#translateFrom

     */

    public void translateFrom(ClassGenerator classGen,

    {

        final ConstantPoolGen cpg = classGen.getConstantPool();

        final InstructionList il = methodGen.getInstructionList();

        if (clazz.getName().equals("java.lang.String")) {

            // same internal representation, convert null to ""

            il.append(DUP);

            final BranchHandle ifNonNull = il.append(new IFNONNULL(null));

            il.append(POP);

            il.append(new PUSH(cpg, ""));

            ifNonNull.setTarget(il.append(NOP));

        }

        else {

            ErrorMsg err = new ErrorMsg(ErrorMsg.DATA_CONVERSION_ERR,

                                        toString(), clazz.getName());

            classGen.getParser().reportError(Constants.FATAL, err);

        }

    }

    /**

     * 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) {

        methodGen.getInstructionList().append(NOP);

    }

    /**

     * Returns the class name of an internal type's external representation.

     */

    public String getClassName() {

        return(STRING_CLASS);

    }

    public Instruction LOAD(int slot) {

        return new ALOAD(slot);

    }

    public Instruction STORE(int slot) {

        return new ASTORE(slot);

    }

}