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/* FJBG -- Fast Java Bytecode Generator
* Copyright 2002-2012 LAMP/EPFL
* @author Michel Schinz
*/
package ch.epfl.lamp.fjbg;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.Iterator;
import java.util.List;
/**
* Code attribute, containing code of methods.
*
* A Code attribute contains the JVM instructions and auxiliary information
* for a single method, instance initialization method, or class or interface
* initialization method. See section 4.8.3 of the JVM specification.
*
* @author Michel Schinz, Stephane Micheloud
* @version 1.1
*/
public class JCodeAttribute extends JAttribute {
protected final JCode code;
protected final JMethod owner;
protected static int UNKNOWN_STACK_SIZE = Integer.MIN_VALUE;
protected final int maxStackSize;
protected final int maxLocals;
public JCodeAttribute(FJBGContext context, JClass clazz, JMethod owner) {
super(context, clazz);
this.owner = owner;
this.maxStackSize = UNKNOWN_STACK_SIZE;
this.maxLocals = 0; // unknown
this.code = owner.getCode();
assert clazz == owner.getOwner();
}
public JCodeAttribute(FJBGContext context,
JClass clazz,
Object owner,
String name,
int size,
DataInputStream stream)
throws IOException {
super(context, clazz, name);
this.owner = (JMethod)owner;
this.maxStackSize = stream.readShort();
this.maxLocals = stream.readShort();
this.code = context.JCode(clazz, (JMethod)owner, stream);
int handlersCount = stream.readShort();
for (int i = 0; i < handlersCount; ++i)
code.addExceptionHandler(code.new ExceptionHandler(stream));
List/*<JAttribute>*/ attributes =
JAttribute.readFrom(context, clazz, code, stream);
Iterator attrIt = attributes.iterator();
while (attrIt.hasNext())
code.addAttribute((JAttribute)attrIt.next());
assert name.equals(getName());
}
public String getName() { return "Code"; }
// Follows javap output format for Code attribute.
/*@Override*/ public String toString() {
StringBuffer buf = new StringBuffer(" Code:");
buf.append("\n Stack=");
buf.append(maxStackSize);
buf.append(", Locals=");
buf.append(maxLocals);
buf.append(", Args_size=");
buf.append(owner.getArgsSize());
buf.append(code);
buf.append("\n");
Iterator it = code.getAttributes().iterator();
while (it.hasNext()) {
JAttribute attr = (JAttribute)it.next();
buf.append(attr);
buf.append("\n");
}
return buf.toString();
}
protected int getSize() {
int handlersNum = code.getExceptionHandlers().size();
int attrsSize = 0;
Iterator attrsIt = code.getAttributes().iterator();
while (attrsIt.hasNext()) {
JAttribute attr = (JAttribute)attrsIt.next();
attrsSize += attr.getSize() + 6;
}
return 2 // max stack
+ 2 // max locals
+ 4 // code size
+ code.getSize() // code
+ 2 // exception table size
+ 8 * handlersNum // exception table
+ 2 // attributes count
+ attrsSize; // attributes
}
protected void writeContentsTo(DataOutputStream stream) throws IOException {
List/*<ExceptionHandler>*/ handlers = code.getExceptionHandlers();
stream.writeShort(code.getMaxStackSize());
stream.writeShort(owner.getMaxLocals());
code.writeTo(stream);
stream.writeShort(handlers.size());
Iterator handlerIt = handlers.iterator();
while (handlerIt.hasNext())
((JCode.ExceptionHandler)handlerIt.next()).writeTo(stream);
JAttribute.writeTo(code.getAttributes(), stream);
}
}
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