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