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/*
* 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 org.apache.bcel.verifier.statics;
import java.util.Hashtable;
import org.apache.bcel.generic.Type;
import org.apache.bcel.verifier.exc.LocalVariableInfoInconsistentException;
/**
* A utility class holding the information about
* the name and the type of a local variable in
* a given slot (== index). This information
* often changes in course of byte code offsets.
*
* @version $Id$
*/
public class LocalVariableInfo{
/** The types database. KEY: String representing the offset integer. */
private final Hashtable<String, Type> types = new Hashtable<>();
/** The names database. KEY: String representing the offset integer. */
private final Hashtable<String, String> names = new Hashtable<>();
/**
* Adds a name of a local variable and a certain slot to our 'names'
* (Hashtable) database.
*/
private void setName(final int offset, final String name) {
names.put(Integer.toString(offset), name);
}
/**
* Adds a type of a local variable and a certain slot to our 'types'
* (Hashtable) database.
*/
private void setType(final int offset, final Type t) {
types.put(Integer.toString(offset), t);
}
/**
* Returns the type of the local variable that uses this local
* variable slot at the given bytecode offset.
* Care for legal bytecode offsets yourself, otherwise the return value
* might be wrong.
* May return 'null' if nothing is known about the type of this local
* variable slot at the given bytecode offset.
*/
public Type getType(final int offset) {
return types.get(Integer.toString(offset));
}
/**
* Returns the name of the local variable that uses this local
* variable slot at the given bytecode offset.
* Care for legal bytecode offsets yourself, otherwise the return value
* might be wrong.
* May return 'null' if nothing is known about the type of this local
* variable slot at the given bytecode offset.
*/
public String getName(final int offset) {
return names.get(Integer.toString(offset));
}
/**
* Adds some information about this local variable (slot).
* @throws LocalVariableInfoInconsistentException if the new information conflicts
* with already gathered information.
*/
public void add(final String name, final int startpc, final int length, final Type t) throws LocalVariableInfoInconsistentException{
for (int i=startpc; i<=startpc+length; i++) { // incl/incl-notation!
add(i,name,t);
}
}
/**
* Adds information about name and type for a given offset.
* @throws LocalVariableInfoInconsistentException if the new information conflicts
* with already gathered information.
*/
private void add(final int offset, final String name, final Type t) throws LocalVariableInfoInconsistentException{
if (getName(offset) != null) {
if (! getName(offset).equals(name)) {
throw new LocalVariableInfoInconsistentException("At bytecode offset '"+offset+
"' a local variable has two different names: '"+getName(offset)+"' and '"+name+"'.");
}
}
if (getType(offset) != null) {
if (! getType(offset).equals(t)) {
throw new LocalVariableInfoInconsistentException("At bytecode offset '"+offset+
"' a local variable has two different types: '"+getType(offset)+"' and '"+t+"'.");
}
}
setName(offset, name);
setType(offset, t);
}
}
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