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/*
* Javassist, a Java-bytecode translator toolkit.
* Copyright (C) 1999-2004 Shigeru Chiba. All Rights Reserved.
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (the "License"); you may not use this file except in compliance with
* the License. Alternatively, the contents of this file may be used under
* the terms of the GNU Lesser General Public License Version 2.1 or later.
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*/
package javassist.bytecode;
import java.io.DataInputStream;
import java.io.IOException;
import java.util.Map;
/**
* <code>LocalVariableTable_attribute</code> or
* <code>LocalVariableTypeTable_attribute</code>.
*/
public class LocalVariableAttribute extends AttributeInfo {
/**
* The name of this attribute <code>"LocalVariableTable"</code>.
*/
public static final String tag = "LocalVariableTable";
/**
* The name of the attribute <code>"LocalVariableTypeTable"</code>.
*/
public static final String typeTag = "LocalVariableTypeTable";
LocalVariableAttribute(ConstPool cp, int n, DataInputStream in)
throws IOException
{
super(cp, n, in);
}
private LocalVariableAttribute(ConstPool cp, byte[] i) {
super(cp, tag, i);
}
/**
* Returns <code>local_variable_table_length</code>.
* This represents the number of entries in the table.
*/
public int tableLength() {
return ByteArray.readU16bit(info, 0);
}
/**
* Returns <code>local_variable_table[i].start_pc</code>.
* This represents the index into the code array from which the local
* variable is effective.
*
* @param i the i-th entry.
*/
public int startPc(int i) {
return ByteArray.readU16bit(info, i * 10 + 2);
}
/**
* Returns <code>local_variable_table[i].length</code>.
* This represents the length of the code region in which the local
* variable is effective.
*
* @param i the i-th entry.
*/
public int codeLength(int i) {
return ByteArray.readU16bit(info, i * 10 + 4);
}
/**
* Adjusts start_pc and length if bytecode is inserted in a method body.
*/
void shiftPc(int where, int gapLength, boolean exclusive) {
int n = tableLength();
for (int i = 0; i < n; ++i) {
int pos = i * 10 + 2;
int pc = ByteArray.readU16bit(info, pos);
int len = ByteArray.readU16bit(info, pos + 2);
if (pc > where || (exclusive && pc == where))
ByteArray.write16bit(pc + gapLength, info, pos);
else if (pc + len > where)
ByteArray.write16bit(len + gapLength, info, pos + 2);
}
}
/**
* Returns the value of <code>local_variable_table[i].name_index</code>.
* This represents the name of the local variable.
*
* @param i the i-th entry.
*/
public int nameIndex(int i) {
return ByteArray.readU16bit(info, i * 10 + 6);
}
/**
* Returns the name of the local variable
* specified by <code>local_variable_table[i].name_index</code>.
*
* @param i the i-th entry.
*/
public String variableName(int i) {
return getConstPool().getUtf8Info(nameIndex(i));
}
/**
* Returns the value of
* <code>local_variable_table[i].descriptor_index</code>.
* This represents the type descriptor of the local variable.
* <p>
* If this attribute represents a LocalVariableTypeTable attribute,
* this method returns the value of
* <code>local_variable_type_table[i].signature_index</code>.
* It represents the type of the local variable.
*
* @param i the i-th entry.
*/
public int descriptorIndex(int i) {
return ByteArray.readU16bit(info, i * 10 + 8);
}
/**
* This method is equivalent to <code>descriptorIndex()</code>.
* If this attribute represents a LocalVariableTypeTable attribute,
* this method should be used instead of <code>descriptorIndex()</code>
* since the method name is more appropriate.
*
* @param i the i-th entry.
* @see #descriptorIndex(int)
*/
public int signatureIndex(int i) {
return descriptorIndex(i);
}
/**
* Returns the type descriptor of the local variable
* specified by <code>local_variable_table[i].descriptor_index</code>.
* <p>
* If this attribute represents a LocalVariableTypeTable attribute,
* this method returns the type signature of the local variable
* specified by <code>local_variable_type_table[i].signature_index</code>.
*
* @param i the i-th entry.
*/
public String descriptor(int i) {
return getConstPool().getUtf8Info(descriptorIndex(i));
}
/**
* This method is equivalent to <code>descriptor()</code>.
* If this attribute represents a LocalVariableTypeTable attribute,
* this method should be used instead of <code>descriptor()</code>
* since the method name is more appropriate.
*
* @param i the i-th entry.
* @see #descriptor(int)
*/
public String signature(int i) {
return descriptor(i);
}
/**
* Returns <code>local_variable_table[i].index</code>.
* This represents the index of the local variable.
*
* @param i the i-th entry.
*/
public int index(int i) {
return ByteArray.readU16bit(info, i * 10 + 10);
}
/**
* Makes a copy.
*
* @param newCp the constant pool table used by the new copy.
* @param classnames should be null.
*/
public AttributeInfo copy(ConstPool newCp, Map classnames) {
byte[] src = get();
byte[] dest = new byte[src.length];
ConstPool cp = getConstPool();
LocalVariableAttribute attr = new LocalVariableAttribute(newCp, dest);
int n = ByteArray.readU16bit(src, 0);
ByteArray.write16bit(n, dest, 0);
int j = 2;
for (int i = 0; i < n; ++i) {
int start = ByteArray.readU16bit(src, j);
int len = ByteArray.readU16bit(src, j + 2);
int name = ByteArray.readU16bit(src, j + 4);
int type = ByteArray.readU16bit(src, j + 6);
int index = ByteArray.readU16bit(src, j + 8);
ByteArray.write16bit(start, dest, j);
ByteArray.write16bit(len, dest, j + 2);
if (name != 0)
name = cp.copy(name, newCp, null);
ByteArray.write16bit(name, dest, j + 4);
if (type != 0)
type = cp.copy(type, newCp, null);
ByteArray.write16bit(type, dest, j + 6);
ByteArray.write16bit(index, dest, j + 8);
j += 10;
}
return attr;
}
}
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