    001/*
    002 * Licensed to the Apache Software Foundation (ASF) under one or more
    003 * contributor license agreements.  See the NOTICE file distributed with
    004 * this work for additional information regarding copyright ownership.
    005 * The ASF licenses this file to You under the Apache License, Version 2.0
    006 * (the "License"); you may not use this file except in compliance with
    007 * the License.  You may obtain a copy of the License at
    008 *
    009 *      http://www.apache.org/licenses/LICENSE-2.0
    010 *
    011 *  Unless required by applicable law or agreed to in writing, software
    012 *  distributed under the License is distributed on an "AS IS" BASIS,
    013 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014 *  See the License for the specific language governing permissions and
    015 *  limitations under the License.
    016 *
    017 */
    018package org.apache.bcel.verifier.statics;
    019
    020
    021import org.apache.bcel.generic.Type;
    022import org.apache.bcel.verifier.exc.AssertionViolatedException;
    023import org.apache.bcel.verifier.exc.LocalVariableInfoInconsistentException;
    024
    025/**
    026 * A utility class holding the information about
    027 * the names and the types of the local variables in
    028 * a given method.
    029 */
    030public class LocalVariablesInfo{
    031
    032    /** The information about the local variables is stored here. */
    033    private final LocalVariableInfo[] localVariableInfos;
    034
    035    /** The constructor. */
    036    LocalVariablesInfo(final int max_locals) {
    037        localVariableInfos = new LocalVariableInfo[max_locals];
    038        for (int i=0; i<max_locals; i++) {
    039            localVariableInfos[i] = new LocalVariableInfo();
    040        }
    041    }
    042
    043    /**
    044     * Returns the LocalVariableInfo for the given slot.
    045     *
    046     * @param slot Slot to query.
    047     * @return The LocalVariableInfo for the given slot.
    048     */
    049    public LocalVariableInfo getLocalVariableInfo(final int slot) {
    050        if (slot < 0 || slot >= localVariableInfos.length) {
    051            throw new AssertionViolatedException("Slot number for local variable information out of range.");
    052        }
    053        return localVariableInfos[slot];
    054    }
    055
    056    /**
    057     * Adds information about the local variable in slot 'slot'. Automatically
    058     * adds information for slot+1 if 't' is Type.LONG or Type.DOUBLE.
    059     *
    060     * @param name variable name
    061     * @param startPc Range in which the variable is valid.
    062     * @param length length of ...
    063     * @param type variable type
    064     * @throws LocalVariableInfoInconsistentException if the new information conflicts
    065     *         with already gathered information.
    066     */
    067    public void add(final int slot, final String name, final int startPc, final int length, final Type type) throws LocalVariableInfoInconsistentException{
    068        // The add operation on LocalVariableInfo may throw the '...Inconsistent...' exception, we don't throw it explicitely here.
    069
    070        if (slot < 0 || slot >= localVariableInfos.length) {
    071            throw new AssertionViolatedException("Slot number for local variable information out of range.");
    072        }
    073
    074        localVariableInfos[slot].add(name, startPc, length, type);
    075        if (type == Type.LONG) {
    076            localVariableInfos[slot+1].add(name, startPc, length, LONG_Upper.theInstance());
    077        }
    078        if (type == Type.DOUBLE) {
    079            localVariableInfos[slot+1].add(name, startPc, length, DOUBLE_Upper.theInstance());
    080        }
    081    }
    082}