// $Id: Jcf.java,v 1.2 2002-07-14 21:28:16+09 kaiya Exp kaiya $

public class Jcf{
private byte[] b;
private boolean ok=false;

private static int[] pooln={
	-1, -2, -1, 4, 4, 8, 8, 2, 2, 4, 4, 4, 4
}; // const. pool width. 

private CP[] pool;
private int thiscp;
private int supercp;
private fieldDef[] fdef;
private methodDef[] mdef;

	public Jcf(byte[] bcode){
		b=bcode;
		ok=parseBytes();
	}
	
	public String className(){
		if(!ok) return null;
		CPClass c=(CPClass)pool[thiscp];
		return new String(c.name.data);
	}

	public String[][] pubVoidMethods(){
		String[][] r=new String[mdef.length][2];
		int n=0;
		for(int i=0; i<mdef.length; i++){
			if((mdef[i].flag&1) == 0) continue; // non-public skip
			if((mdef[i].flag&8) != 0) continue; // static skip
			String t=new String(mdef[i].type.data);
			if(!t.equals("()V")) continue;
			String s=new String(mdef[i].name.data);
			if(s.equals("<init>")) continue;

			r[n][0]=s; r[n][1]=t;
			n++;
		}
		String[][] rr=new String[n][2];
		for(int i=0; i<n; i++)for(int j=0; j<2; j++) rr[i][j]=r[i][j];
		return rr;
	}

	public String[][] methods(){
		String[][] r=new String[mdef.length][2];
		for(int i=0; i<mdef.length; i++){
			r[i][0]=new String(mdef[i].name.data);
			r[i][1]=new String(mdef[i].type.data);
		}
		return r;
	}

	public String[][] fields(){
		String[][] r=new String[fdef.length][2];
		for(int i=0; i<fdef.length; i++){
			r[i][0]=new String(fdef[i].name.data);
			r[i][1]=new String(fdef[i].type.data);
		}
		return r;
	}

	public String[][] usedMethods(){
		int n=0;
		String[][] r=new String[pool.length][3];
		for(int i=0; i<pool.length; i++){
			if(pool[i].cptype == 10){
				CPMethod c=(CPMethod)pool[i];
				r[n][0]=new String(c.inclass.name.data);
				r[n][1]=new String(c.nametype.name.data);
				r[n][2]=new String(c.nametype.type.data);
				n++;
			}
		}
		String[][] rr=new String[n][3];
		for(int i=0; i<n; i++) for(int j=0; j<3; j++) rr[i][j]=r[i][j];

		return rr;
	}

	public String[][] usedFields(){
		int n=0;
		String[][] r=new String[pool.length][3];
		for(int i=0; i<pool.length; i++){
			if(pool[i].cptype == 9){
				CPField c=(CPField)pool[i];
				r[n][0]=new String(c.inclass.name.data);
				r[n][1]=new String(c.nametype.name.data);
				r[n][2]=new String(c.nametype.type.data);
				n++;
			}
		}
		String[][] rr=new String[n][3];
		for(int i=0; i<n; i++) for(int j=0; j<3; j++) rr[i][j]=r[i][j];

		return rr;
	}

	private boolean parseBytes(){
		if(b.length<10) return false;
		int cpn=bytes2int(b, 8, 2)-1;
		pool= new CP[cpn];
		int ptr=10;
		for(int i=0; i<cpn; i++){
			int cpi=(int)b[ptr];
			switch(cpi){
				case  7: pool[i]= new CPClass(); break;
				case  8: pool[i]= new CPString(); break;
				case  9: pool[i]= new CPField(); break;
				case 10: pool[i]= new CPMethod(); break;
				case 11: pool[i]= new CPIMethod(); break;
				case 12: pool[i]= new CPNameType(); break;
				default: pool[i]= new CP(); break;
			}
			pool[i].cptype=cpi;
			ptr++;

			if(cpi==1){
				int len=bytes2int(b, ptr, 2);
				ptr += 2;
				pool[i].data=new byte[len];
				System.arraycopy(b, ptr, pool[i].data, 0, len);
				ptr += len;
			}else{
				pool[i].data=new byte[pooln[cpi]];
				System.arraycopy(b, ptr, pool[i].data, 0, pooln[cpi]);
				ptr += pooln[cpi];
			}
		}
		cpResolve();

		// skip acc flag of this class.
		ptr +=2;

		thiscp=bytes2int(b, ptr, 2)-1;
		ptr +=2;

		supercp=bytes2int(b, ptr, 2)-1;
		ptr +=2;

		int implif=bytes2int(b, ptr, 2);
		ptr +=2;
		for(int i=0; i<implif; i++) ptr += 2;

		fdef= new fieldDef[bytes2int(b, ptr, 2)];
		ptr +=2;
		for(int i=0; i<fdef.length; i++){
			fdef[i]=new fieldDef();
			fdef[i].flag=bytes2int(b, ptr, 2);
			ptr +=2;
			fdef[i].name=id2cp(bytes2int(b, ptr, 2));
			ptr +=2;
			fdef[i].type=id2cp(bytes2int(b, ptr, 2));
			ptr +=2;
			int ai=bytes2int(b, ptr, 2);
			ptr +=2;
			for(int j=0; j<ai; j++) ptr=parseAttr(ptr);
		}

		mdef= new methodDef[bytes2int(b, ptr, 2)];
		ptr +=2;
		for(int i=0; i<mdef.length; i++){
			mdef[i]=new methodDef();
			mdef[i].flag=bytes2int(b, ptr, 2);
			ptr +=2;
			mdef[i].name=id2cp(bytes2int(b, ptr, 2));
			ptr +=2;
			mdef[i].type=id2cp(bytes2int(b, ptr, 2));
			ptr +=2;
			int ai=bytes2int(b, ptr, 2);
			ptr +=2;
			for(int j=0; j<ai; j++) ptr=parseAttr(ptr);
		}

		return true;
	}

	private int parseAttr(int ptr){
		// skip attr. type
		ptr +=2;

		int w=bytes2int(b, ptr, 4);
		ptr +=4;
		// skip attr. body
		ptr += w;
		return ptr;
	}

	private void cpResolve(){
		for(int i=0; i<pool.length; i++){
			int cpt= pool[i].cptype;
			switch(cpt){
				case  7:
					{CPClass c=(CPClass)pool[i];
					c.name = id2cp(bytes2int(c.data, 0, 2));}
				break;
				case  8:
					{CPString c=(CPString)pool[i];
					c.name = id2cp(bytes2int(c.data, 0, 2));}
				break;
				case  9:
					{CPField c=(CPField)pool[i];
					c.inclass = (CPClass)id2cp(bytes2int(c.data, 0, 2));
					c.nametype = (CPNameType)id2cp(bytes2int(c.data, 2, 2));}
				break;
				case  10:
					{CPMethod c=(CPMethod)pool[i];
					c.inclass = (CPClass)id2cp(bytes2int(c.data, 0, 2));
					c.nametype = (CPNameType)id2cp(bytes2int(c.data, 2, 2));}
				break;
				case  11:
					{CPIMethod c=(CPIMethod)pool[i];
					c.inclass = (CPClass)id2cp(bytes2int(c.data, 0, 2));
					c.nametype = (CPNameType)id2cp(bytes2int(c.data, 2, 2));}
				break;
				case  12:
					{CPNameType c=(CPNameType)pool[i];
					c.name = id2cp(bytes2int(c.data, 0, 2));
					c.type = id2cp(bytes2int(c.data, 2, 2));}
				break;
			}
		}
	}

	private CP id2cp(int id){
		for(int j=0; j<pool.length; j++){
			if(id == j+1) return pool[j];
		}
		return null;
	}

	private class CP{ int cptype; byte[] data; }

	private class CPClass extends CP{ CP name; }
	private class CPString extends CP{ CP name; }
	private class CPField extends CP{ CPClass inclass; CPNameType nametype; }
	private class CPMethod extends CP{ CPClass inclass; CPNameType nametype; }
	private class CPIMethod extends CP{ CPClass inclass; CPNameType nametype; }
	private class CPNameType extends CP{ CP name, type; }

	private class fieldDef{ int flag; CP name, type; }
	private class methodDef{ int flag; CP name, type; }

	private int bytes2int(byte[] b, int of, int sz){
	int r=0, p=1;
		for(int i=0; i<sz; i++){
			r += (int)b[of+sz-1-i] * p;
			p = p*256;
		}
		return r;
	}

	private long bytes2long(byte[] b, int of, int sz){
	long r=0, p=1;
		for(int i=0; i<sz; i++){
			r += (int)b[of+sz-1-i] * p;
			p = p*256;
		}
		return r;
	}
}