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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.convert;
import javassist.CtClass;
import javassist.CtMethod;
import javassist.NotFoundException;
import javassist.bytecode.*;
public class TransformBefore extends TransformCall {
protected CtClass[] parameterTypes;
protected int locals;
protected int maxLocals;
protected byte[] saveCode, loadCode;
public TransformBefore(Transformer next,
CtMethod origMethod, CtMethod beforeMethod)
throws NotFoundException
{
super(next, origMethod, beforeMethod);
parameterTypes = origMethod.getParameterTypes();
locals = 0;
maxLocals = 0;
saveCode = loadCode = null;
}
public void initialize(ConstPool cp, CodeAttribute attr) {
super.initialize(cp, attr);
locals = 0;
maxLocals = attr.getMaxLocals();
saveCode = loadCode = null;
}
protected int match(int c, int pos, CodeIterator iterator,
int typedesc, ConstPool cp) throws BadBytecode
{
if (newIndex == 0) {
String desc = Descriptor.ofParameters(parameterTypes) + 'V';
desc = Descriptor.insertParameter(classname, desc);
int nt = cp.addNameAndTypeInfo(newMethodname, desc);
int ci = cp.addClassInfo(newClassname);
newIndex = cp.addMethodrefInfo(ci, nt);
constPool = cp;
}
if (saveCode == null)
makeCode(parameterTypes, cp);
return match2(pos, iterator);
}
protected int match2(int pos, CodeIterator iterator) throws BadBytecode {
iterator.move(pos);
iterator.insert(saveCode);
iterator.insert(loadCode);
int p = iterator.insertGap(3);
iterator.writeByte(INVOKESTATIC, p);
iterator.write16bit(newIndex, p + 1);
iterator.insert(loadCode);
return iterator.next();
}
public int extraLocals() { return locals; }
protected void makeCode(CtClass[] paramTypes, ConstPool cp) {
Bytecode save = new Bytecode(cp, 0, 0);
Bytecode load = new Bytecode(cp, 0, 0);
int var = maxLocals;
int len = (paramTypes == null) ? 0 : paramTypes.length;
load.addAload(var);
makeCode2(save, load, 0, len, paramTypes, var + 1);
save.addAstore(var);
saveCode = save.get();
loadCode = load.get();
}
private void makeCode2(Bytecode save, Bytecode load,
int i, int n, CtClass[] paramTypes, int var)
{
if (i < n) {
int size = load.addLoad(var, paramTypes[i]);
makeCode2(save, load, i + 1, n, paramTypes, var + size);
save.addStore(var, paramTypes[i]);
}
else
locals = var - maxLocals;
}
}
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