package test;

import java.util.GregorianCalendar;

import org.ldp.jdasm.*;
import org.ldp.jdasm.attribute.*;
import org.ldp.jdasm.attribute.instruction.*;
import org.ldp.jdasm.attribute.instruction.opcode.*;
import org.ldp.jdasm.exception.*;

public class JDASM_HelloWorldBuilder {

	public static void main( String[] argv )
	{
		try {
			double startTime = new GregorianCalendar().getTimeInMillis();
			
			DClass d = new DClass("HelloWorld");
			DMethod m = d.addMethod( "public static void main( java.lang.String[] argv )");
			CodeAttribute code = m.getCodeAttribute();
			
		
			Instruction start1 = code.addCode(new NEW("java/io/BufferedReader"));
			code.addCode(new DUP());
			code.addCode(new NEW("java/io/InputStreamReader"));
			code.addCode(new DUP());
			code.addCode(new GETSTATIC("java/lang/System in Ljava/io/InputStream;"));
			code.addCode(new INVOKESPECIAL("java/io/InputStreamReader <init> (Ljava/io/InputStream;)V"));
			code.addCode(new INVOKESPECIAL("java/io/BufferedReader <init> (Ljava/io/Reader;)V"));
			Instruction start2 = code.addCode(new ASTORE_1());
			code.addCode(new ACONST_NULL());
			Instruction start3 = code.addCode(new ASTORE_2());
			Instruction tryStart = code.addCode(new GETSTATIC("java/lang/System out Ljava/io/PrintStream;"));
			code.addCode(new LDC("Please enter your name> ", false));
			code.addCode(new INVOKEVIRTUAL("java/io/PrintStream print (Ljava/lang/String;)V"));
			code.addCode(new ALOAD_1());
			code.addCode(new INVOKEVIRTUAL("java/io/BufferedReader readLine ()Ljava/lang/String;"));
			code.addCode(new ASTORE_2());
			Instruction go = code.addCode(new GOTO());
			Instruction catchStart = code.addCode(new RETURN());
			go.setJumpTarget( code.addCode(new GETSTATIC("java/lang/System out Ljava/io/PrintStream;")) );
			code.addCode(new NEW("java/lang/StringBuffer"));
			code.addCode(new DUP());
			code.addCode(new LDC("Hallo, ", false));
			code.addCode(new INVOKESPECIAL("java/lang/StringBuffer <init> (Ljava/lang/String;)V"));
			code.addCode(new ALOAD_2());
			code.addCode(new INVOKEVIRTUAL("java/lang/StringBuffer append (Ljava/lang/String;)Ljava/lang/StringBuffer;"));
			code.addCode(new INVOKEVIRTUAL("java/lang/StringBuffer toString ()Ljava/lang/String;"));
			code.addCode(new INVOKEVIRTUAL("java/io/PrintStream println (Ljava/lang/String;)V"));
			Instruction end = code.addCode(new RETURN());


			code.addException(new ExceptionElement(tryStart,catchStart,catchStart, "java/io/IOException"));
			
			LocalVariableTableAttribute tab = (LocalVariableTableAttribute)code.addAttribute(new LocalVariableTableAttribute());
			tab.add( new LocalVariableTableElement(start1, end, "argv", "Ljava/lang/String;", 0));
			tab.add( new LocalVariableTableElement(start2, end, "in", "Ljava/io/BufferedReader;", 1));
			tab.add( new LocalVariableTableElement(start3, end, "name", "Ljava/lang/String;", 2));
			
			d.addEmptyConstructor();
			
			d.addAttribute(new SourceFileAttribute("<generated>"));
			
			// * build
			d.build();
			
			double endTime = new GregorianCalendar().getTimeInMillis();
			System.out.println("Class created in " + (endTime-startTime) + " ms");
			

			d.writeClassToFile(".");
			
			
		} catch( CodeParseException e) {
			System.out.println("Hai sbagliato a scrivere: " + e );
		}
	}
}