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package cuchaz.enigma.bytecode;
import javassist.CtBehavior;
import javassist.CtClass;
import javassist.bytecode.ByteArray;
import javassist.bytecode.CodeAttribute;
import javassist.bytecode.ConstPool;
import javassist.bytecode.LocalVariableAttribute;
import javassist.bytecode.LocalVariableTypeAttribute;
import cuchaz.enigma.mapping.ArgumentEntry;
import cuchaz.enigma.mapping.BehaviorEntry;
import cuchaz.enigma.mapping.EntryFactory;
import cuchaz.enigma.mapping.Translator;
public class LocalVariableRenamer {
private Translator m_translator;
public LocalVariableRenamer(Translator translator) {
m_translator = translator;
}
public void rename(CtClass c) {
for (CtBehavior behavior : c.getDeclaredBehaviors()) {
// if there's a local variable table, just rename everything to v1, v2, v3, ... for now
CodeAttribute codeAttribute = behavior.getMethodInfo().getCodeAttribute();
if (codeAttribute == null) {
continue;
}
BehaviorEntry behaviorEntry = EntryFactory.getBehaviorEntry(behavior);
ConstPool constants = c.getClassFile().getConstPool();
LocalVariableAttribute table = (LocalVariableAttribute)codeAttribute.getAttribute(LocalVariableAttribute.tag);
if (table != null) {
renameLVT(behaviorEntry, constants, table);
}
LocalVariableTypeAttribute typeTable = (LocalVariableTypeAttribute)codeAttribute.getAttribute(LocalVariableAttribute.typeTag);
if (typeTable != null) {
renameLVTT(typeTable, table);
}
}
}
// DEBUG
@SuppressWarnings("unused")
private void dumpTable(LocalVariableAttribute table) {
for (int i=0; i<table.tableLength(); i++) {
System.out.println(String.format("\t%d (%d): %s %s",
i, table.index(i), table.variableName(i), table.descriptor(i)
));
}
}
private void renameLVT(BehaviorEntry behaviorEntry, ConstPool constants, LocalVariableAttribute table) {
// skip empty tables
if (table.tableLength() <= 0) {
return;
}
// where do we start counting variables?
int starti = 0;
if (table.variableName(0).equals("this")) {
// skip the "this" variable
starti = 1;
}
// rename method arguments first
int numArgs = 0;
if (behaviorEntry.getSignature() != null) {
numArgs = behaviorEntry.getSignature().getArgumentTypes().size();
for (int i=starti; i<starti + numArgs && i<table.tableLength(); i++) {
int argi = i - starti;
String argName = m_translator.translate(new ArgumentEntry(behaviorEntry, argi, ""));
if (argName == null) {
argName = "a" + (argi + 1);
}
renameVariable(table, i, constants.addUtf8Info(argName));
}
}
// then rename the rest of the args, if any
for (int i=starti + numArgs; i<table.tableLength(); i++) {
int firstIndex = table.index(starti + numArgs);
renameVariable(table, i, constants.addUtf8Info("v" + (table.index(i) - firstIndex + 1)));
}
}
private void renameLVTT(LocalVariableTypeAttribute typeTable, LocalVariableAttribute table) {
// rename args to the same names as in the LVT
for (int i=0; i<typeTable.tableLength(); i++) {
renameVariable(typeTable, i, getNameIndex(table, typeTable.index(i)));
}
}
private void renameVariable(LocalVariableAttribute table, int i, int stringId) {
// based off of LocalVariableAttribute.nameIndex()
ByteArray.write16bit(stringId, table.get(), i*10 + 6);
}
private int getNameIndex(LocalVariableAttribute table, int index) {
for (int i=0; i<table.tableLength(); i++) {
if (table.index(i) == index) {
return table.nameIndex(i);
}
}
return 0;
}
}
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