1 files changed, 119 insertions, 0 deletions

diff --git a/src/main/java/cuchaz/enigma/bytecode/LocalVariableRenamer.java b/src/main/java/cuchaz/enigma/bytecode/LocalVariableRenamer.java
new file mode 100644
index 0000000..d0ce107
--- /dev/null
+++ b/src/main/java/cuchaz/enigma/bytecode/LocalVariableRenamer.java
@@ -0,0 +1,119 @@
+/*******************************************************************************
+ * Copyright (c) 2015 Jeff Martin.
+ * All rights reserved. This program and the accompanying materials
+ * are made available under the terms of the GNU Lesser General Public
+ * License v3.0 which accompanies this distribution, and is available at
+ * http://www.gnu.org/licenses/lgpl.html
+ * <p>
+ * Contributors:
+ * Jeff Martin - initial API and implementation
+ ******************************************************************************/
+package cuchaz.enigma.bytecode;
+
+import cuchaz.enigma.mapping.ArgumentEntry;
+import cuchaz.enigma.mapping.BehaviorEntry;
+import cuchaz.enigma.mapping.EntryFactory;
+import cuchaz.enigma.mapping.Translator;
+import javassist.CtBehavior;
+import javassist.CtClass;
+import javassist.bytecode.*;
+
+
+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;
+    }
+}