package de.dhbwstuttgart.JvmDisassembler;

import java.util.*;
import java.io.*;

import de.dhbwstuttgart.typeinference.Menge;

//GenricsTest.java Testfile fuer jvmDisassembler
class jvmDisassembler {

    static int makePosByte(int code) {
	return (code & 0x7f | code & 0x80); 
    }

    static int makePosShort(int code) {
	return (code & 0x7fff | code & 0x8000); 
    }

    static long makePosInt(long code) {
	return (code & 0x7fffffff | code & 0x80000000); 
    }

    static void parse_attribute(DataInputStream d, Menge<String> const_pool) throws IOException, Exception {
	int attribut_count = d.readShort();
	System.out.println("attribut_count = " + attribut_count);
	if (attribut_count == 0) System.out.println("attributes = {}");
	else {
	    for (int j = 0; j < attribut_count; j++) {
		System.out.println("attribut[" + j + "] =\n{");
		int attribut_name_index = d.readShort();
		System.out.println("attribut_name_index = " + attribut_name_index
				   + "  //" + const_pool.elementAt(makePosShort(attribut_name_index)));
		
		if (const_pool.elementAt(makePosShort(attribut_name_index)).equals("Code")) {
		    parse_code(d, const_pool);
		    int exception_table_length = d.readShort();
		    System.out.println("exception_table_length = " + exception_table_length);
		    if (exception_table_length == 0) System.out.println("exception_table = {}");
		    else throw new Exception("exceptiones not implemented");

		    parse_attribute(d, const_pool);

		} else {
		    if ((const_pool.elementAt(makePosShort(attribut_name_index)).equals("Signature"))) {
			long attribut_length = d.readInt();
			System.out.println("attribut_length = " + attribut_length);
			
			int sigdescriptor_index = d.readShort();
			System.out.println("descriptor_index = " + sigdescriptor_index
					   + "  //" + const_pool.elementAt(makePosShort(sigdescriptor_index)));
		    } else {
			long attribut_length = d.readInt();
			System.out.println("attribut_length = " + attribut_length);
		    
			for(int ll = 0; ll < attribut_length; ll++) {
			    System.out.println(Integer.toHexString(makePosByte(d.readByte())));
			}
			System.out.println("}");
		    }
		}
		System.out.println("}");
	    }
	}

    }

    static void parse_code(DataInputStream d, Menge<String> const_pool) throws IOException {
	long attribut_length = d.readInt();
	System.out.println("attribut_length = " + attribut_length);
	
	int max_stack = d.readShort();
	System.out.println("max_stack = " + max_stack);
	
	int max_locals = d.readShort();
	System.out.println("max_locals = " + max_locals);
	
	long code_length = makePosInt(d.readInt());
	System.out.println("code_length = " + code_length);
	System.out.println("code =\n{");
	
	int code;
	int codenr = 1;
	for(; codenr <= code_length;) {
				//CODE VERVOLLSTAENDIGEN PL 06-04-01
	    code = makePosByte(d.readByte());
				//System.out.println("DEBUG: " + Integer.toHexString(code));
	    switch(code) {
	    case 0x4: System.out.println("   " + codenr + " iconst_1"); 
		codenr++;
		break;
	    case 0x2a: System.out.println("   " + codenr + " aload_0"); 
		codenr++;
		break;
	    case 0x2b: System.out.println("   " + codenr + " aload_1"); 
		codenr++;
		break;
	    case 0x2c: System.out.println("   " + codenr + " aload_2"); 
		codenr++;
		break;
	    case 0xac: System.out.println("   " + codenr + " ireturn"); 
		codenr++;
		break;
	    case 0xb0: System.out.println("   " + codenr + " areturn"); 
		codenr++;
		break;
	    case 0xb1: System.out.println("   " + codenr + " return"); 
		codenr++;
		break;
	    case 0xb7: System.out.println("   " + codenr + " invokespecial " + 
					  d.readShort());
	    codenr+=3;
	    break;
	    default: System.out.println("   " + Integer.toHexString(code));
		codenr++;
		break;
	    }
	}
	System.out.println("}");
    }


    public static void main (String[] args) throws FileNotFoundException, IOException, Exception {

	DataInputStream d = new DataInputStream(new FileInputStream(new File (args[0])));

	int magic = d.readInt();
	System.out.println("magic = 0x " + Integer.toHexString(magic));
	
	int minor = d.readShort();
	System.out.println("minor_version = " + minor);
	int major = d.readShort();
	System.out.println("major_version = " + major);

	//CONSTANT POOL START
	int constant_pool_count = makePosShort(d.readShort());
	System.out.println("constant_pool_count = " + constant_pool_count);
	
	Menge<String> const_pool = new Menge<String>();
	const_pool.addElement(""); // Konstatenpool beginnt bei 1, Stelle 0 auffuellen

	System.out.println("constant_pool =\n{");
	short constant_pool_tag;
	for (int i = 1; i < constant_pool_count; i++) {
	    constant_pool_tag = d.readByte();
	    switch(constant_pool_tag) {
		//Tags vervollstaendigen PL 06-04-01
	    case 1: System.out.print(i + "| tag = CONSTANT_Utf8, length = ");
		int length = makePosShort(d.readShort());
		System.out.print(length + ", ");
		byte[] bytes = new byte[length];
		d.read(bytes, 0, length);
		System.out.println(new String(bytes));
		const_pool.addElement(new String(bytes));
		break;
	    case 7: System.out.println(i + "| tag = CONSTANT_Class, name_index = " + d.readShort());
		const_pool.addElement("");
		break;
	    case 10: System.out.println(i + "| tag = CONSTANT_Methodref, class_index = " + 
				      d.readShort() + ", name_and_type_index = " + d.readShort());
		const_pool.addElement("");
		break;
	    case 12:System.out.println(i + "| tag = CONSTANT_NameAndType, name_index = "  + 
				     d.readShort() + ", descriptor_index = " + d.readShort());
		const_pool.addElement("");
		break;
	    }
	}
	//CONSTANT POOL END

	int access_flags = d.readShort();
	System.out.println("access_flags = " + access_flags);
	int this_class = d.readShort();
	System.out.println("this_class = " + this_class);
	int super_class = d.readShort();
	System.out.println("super_class = " + super_class);

	//INTERFACE START
	int interface_count = d.readShort();
	System.out.println("interface_count = " + interface_count);
	if (interface_count == 0) System.out.println("interfaces ={}");
	else 
	    //Interface implementieren PL 06-04-01
	    throw new Exception("no interfaces implemented");
	//INTERFACE END

	//FIELD START
	int field_count = d.readShort();
	System.out.println("field_count = " + field_count);
	if (field_count == 0) System.out.println("fields = {}");
	else {
	    for(int o = 1; o <= field_count; o++) {
		System.out.println("field[" + o + "] =\n{");
		int faccess_flags = d.readShort();
		System.out.println("access_flags = " + faccess_flags);
		int fname_index = d.readShort();
		System.out.println("name_index = " + fname_index);
		int fdescriptor_index = d.readShort();
		System.out.println("descriptor_index = " + fdescriptor_index);

		parse_attribute(d, const_pool);
 		System.out.println("}");
	    }
	}
	//FIELD END
	
	//METHOD START
	int method_count = makePosShort(d.readShort());
	System.out.println("method_count = " + method_count);
	if (method_count == 0) System.out.println("methods ={}");
	else {
	    for(int i = 1; i <= method_count; i++) {
		System.out.println("method[" + i + "] =\n{");
		int maccess_flags = d.readShort();
		System.out.println("access_flags = " + maccess_flags);
		int mname_index = d.readShort();
		System.out.println("name_index = " + mname_index);
		int descriptor_index = d.readShort();
		System.out.println("descriptor_index = " + descriptor_index);
		
		parse_attribute(d, const_pool);

		System.out.println("}");
	    }
	}
	//METHOD END

	//FILE ATTRIBUTES START
	parse_attribute(d, const_pool);
	//FILE ATTRIBUTES END
    }
}