/*
 * 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
 *
 *   https://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 org.apache.bcel.generic;

import org.apache.bcel.Const;
import org.apache.bcel.ExceptionConst;

/**
 * Super class for the xRETURN family of instructions.
 */
public abstract class ReturnInstruction extends Instruction implements ExceptionThrower, TypedInstruction, StackConsumer {

    /**
     * Empty constructor needed for Instruction.readInstruction. Not to be used otherwise.
     */
    ReturnInstruction() {
    }

    /**
     * Constructs a ReturnInstruction.
     *
     * @param opcode of instruction.
     */
    protected ReturnInstruction(final short opcode) {
        super(opcode, (short) 1);
    }

    @Override
    public Class<?>[] getExceptions() {
        return new Class[] {ExceptionConst.ILLEGAL_MONITOR_STATE};
    }

    public Type getType() {
        final short opcode = super.getOpcode();
        switch (opcode) {
        case Const.IRETURN:
            return Type.INT;
        case Const.LRETURN:
            return Type.LONG;
        case Const.FRETURN:
            return Type.FLOAT;
        case Const.DRETURN:
            return Type.DOUBLE;
        case Const.ARETURN:
            return Type.OBJECT;
        case Const.RETURN:
            return Type.VOID;
        default: // Never reached
            throw new ClassGenException("Unknown type " + opcode);
        }
    }

    /**
     * @return type associated with the instruction.
     */
    @Override
    public Type getType(final ConstantPoolGen cp) {
        return getType();
    }
}
