package fugue;

public class GFutils {
	static void dump(short[][] M,String comment){
		if(true) //Turn debugging on/off here
		for(int j=0;j0?"":" "+comment));

	static short GFlog(short a){
		short ltable[] = {
		0x00, 0xff, 0xc8, 0x08, 0x91, 0x10, 0xd0, 0x36, 
		0x5a, 0x3e, 0xd8, 0x43, 0x99, 0x77, 0xfe, 0x18, 
		0x23, 0x20, 0x07, 0x70, 0xa1, 0x6c, 0x0c, 0x7f, 
		0x62, 0x8b, 0x40, 0x46, 0xc7, 0x4b, 0xe0, 0x0e, 
		0xeb, 0x16, 0xe8, 0xad, 0xcf, 0xcd, 0x39, 0x53, 
		0x6a, 0x27, 0x35, 0x93, 0xd4, 0x4e, 0x48, 0xc3, 
		0x2b, 0x79, 0x54, 0x28, 0x09, 0x78, 0x0f, 0x21, 
		0x90, 0x87, 0x14, 0x2a, 0xa9, 0x9c, 0xd6, 0x74, 
		0xb4, 0x7c, 0xde, 0xed, 0xb1, 0x86, 0x76, 0xa4, 
		0x98, 0xe2, 0x96, 0x8f, 0x02, 0x32, 0x1c, 0xc1, 
		0x33, 0xee, 0xef, 0x81, 0xfd, 0x30, 0x5c, 0x13, 
		0x9d, 0x29, 0x17, 0xc4, 0x11, 0x44, 0x8c, 0x80, 
		0xf3, 0x73, 0x42, 0x1e, 0x1d, 0xb5, 0xf0, 0x12, 
		0xd1, 0x5b, 0x41, 0xa2, 0xd7, 0x2c, 0xe9, 0xd5, 
		0x59, 0xcb, 0x50, 0xa8, 0xdc, 0xfc, 0xf2, 0x56, 
		0x72, 0xa6, 0x65, 0x2f, 0x9f, 0x9b, 0x3d, 0xba, 
		0x7d, 0xc2, 0x45, 0x82, 0xa7, 0x57, 0xb6, 0xa3, 
		0x7a, 0x75, 0x4f, 0xae, 0x3f, 0x37, 0x6d, 0x47, 
		0x61, 0xbe, 0xab, 0xd3, 0x5f, 0xb0, 0x58, 0xaf, 
		0xca, 0x5e, 0xfa, 0x85, 0xe4, 0x4d, 0x8a, 0x05, 
		0xfb, 0x60, 0xb7, 0x7b, 0xb8, 0x26, 0x4a, 0x67, 
		0xc6, 0x1a, 0xf8, 0x69, 0x25, 0xb3, 0xdb, 0xbd, 
		0x66, 0xdd, 0xf1, 0xd2, 0xdf, 0x03, 0x8d, 0x34, 
		0xd9, 0x92, 0x0d, 0x63, 0x55, 0xaa, 0x49, 0xec, 
		0xbc, 0x95, 0x3c, 0x84, 0x0b, 0xf5, 0xe6, 0xe7, 
		0xe5, 0xac, 0x7e, 0x6e, 0xb9, 0xf9, 0xda, 0x8e, 
		0x9a, 0xc9, 0x24, 0xe1, 0x0a, 0x15, 0x6b, 0x3a, 
		0xa0, 0x51, 0xf4, 0xea, 0xb2, 0x97, 0x9e, 0x5d, 
		0x22, 0x88, 0x94, 0xce, 0x19, 0x01, 0x71, 0x4c, 
		0xa5, 0xe3, 0xc5, 0x31, 0xbb, 0xcc, 0x1f, 0x2d, 
		0x3b, 0x52, 0x6f, 0xf6, 0x2e, 0x89, 0xf7, 0xc0, 
		0x68, 0x1b, 0x64, 0x04, 0x06, 0xbf, 0x83, 0x38 };
		return ltable[a];
	static short GFexp(short a){
		/* Anti-log table: */
		short atable[] = {
		0x01, 0xe5, 0x4c, 0xb5, 0xfb, 0x9f, 0xfc, 0x12, 
		0x03, 0x34, 0xd4, 0xc4, 0x16, 0xba, 0x1f, 0x36, 
		0x05, 0x5c, 0x67, 0x57, 0x3a, 0xd5, 0x21, 0x5a, 
		0x0f, 0xe4, 0xa9, 0xf9, 0x4e, 0x64, 0x63, 0xee, 
		0x11, 0x37, 0xe0, 0x10, 0xd2, 0xac, 0xa5, 0x29, 
		0x33, 0x59, 0x3b, 0x30, 0x6d, 0xef, 0xf4, 0x7b, 
		0x55, 0xeb, 0x4d, 0x50, 0xb7, 0x2a, 0x07, 0x8d, 
		0xff, 0x26, 0xd7, 0xf0, 0xc2, 0x7e, 0x09, 0x8c, 
		0x1a, 0x6a, 0x62, 0x0b, 0x5d, 0x82, 0x1b, 0x8f, 
		0x2e, 0xbe, 0xa6, 0x1d, 0xe7, 0x9d, 0x2d, 0x8a, 
		0x72, 0xd9, 0xf1, 0x27, 0x32, 0xbc, 0x77, 0x85, 
		0x96, 0x70, 0x08, 0x69, 0x56, 0xdf, 0x99, 0x94, 
		0xa1, 0x90, 0x18, 0xbb, 0xfa, 0x7a, 0xb0, 0xa7, 
		0xf8, 0xab, 0x28, 0xd6, 0x15, 0x8e, 0xcb, 0xf2, 
		0x13, 0xe6, 0x78, 0x61, 0x3f, 0x89, 0x46, 0x0d, 
		0x35, 0x31, 0x88, 0xa3, 0x41, 0x80, 0xca, 0x17, 
		0x5f, 0x53, 0x83, 0xfe, 0xc3, 0x9b, 0x45, 0x39, 
		0xe1, 0xf5, 0x9e, 0x19, 0x5e, 0xb6, 0xcf, 0x4b, 
		0x38, 0x04, 0xb9, 0x2b, 0xe2, 0xc1, 0x4a, 0xdd, 
		0x48, 0x0c, 0xd0, 0x7d, 0x3d, 0x58, 0xde, 0x7c, 
		0xd8, 0x14, 0x6b, 0x87, 0x47, 0xe8, 0x79, 0x84, 
		0x73, 0x3c, 0xbd, 0x92, 0xc9, 0x23, 0x8b, 0x97, 
		0x95, 0x44, 0xdc, 0xad, 0x40, 0x65, 0x86, 0xa2, 
		0xa4, 0xcc, 0x7f, 0xec, 0xc0, 0xaf, 0x91, 0xfd, 
		0xf7, 0x4f, 0x81, 0x2f, 0x5b, 0xea, 0xa8, 0x1c, 
		0x02, 0xd1, 0x98, 0x71, 0xed, 0x25, 0xe3, 0x24, 
		0x06, 0x68, 0xb3, 0x93, 0x2c, 0x6f, 0x3e, 0x6c, 
		0x0a, 0xb8, 0xce, 0xae, 0x74, 0xb1, 0x42, 0xb4, 
		0x1e, 0xd3, 0x49, 0xe9, 0x9c, 0xc8, 0xc6, 0xc7, 
		0x22, 0x6e, 0xdb, 0x20, 0xbf, 0x43, 0x51, 0x52, 
		0x66, 0xb2, 0x76, 0x60, 0xda, 0xc5, 0xf3, 0xf6, 
		0xaa, 0xcd, 0x9a, 0xa0, 0x75, 0x54, 0x0e, 0x01 };
		return atable[a];

	static short GFadd(short a,short b){
		return (short)(a^b);
	static short GFsub(short a,short b){
		return (short)(a^b); //addition and subtraction are the same in GF(2^8)
	static short GFmult(short a,short b){
		if(a==0 || b==0)
			return 0;
			return GFexp((short)((GFlog(a)+GFlog(b))%256));
	static short GFmult(short a, short b){
		short p = 0;
		short counter;
		short hi_bit_set;
			if((b & 1) == 1) 
				p ^= a;
			hi_bit_set=(short)(a & 0x80);
			a <<= 1;
			if(hi_bit_set == 0x80) 
				a ^= 0x1b;		
			b >>= 1;
		return (short)(p%256);

	static short GFdiv(short a, short b){
		return GFexp((short)((GFlog(a)-GFlog(b))%256));
	static short GFinv(short a){
			return (short)0;
			return GFexp((short)((0xFF-GFlog(a))%256)); //0xFF is the GFlog of 1
	static short[][] GFmatrixmult(short[][] a,short[][] b){
		short[][] c=new short[b.length][a[0].length];
		if(a.length!=b[0].length) //# cols in A = # rows in B
			return null; //Size mismatch
		for(int i=0;i0;i--){ //Rückwärts von letzter bis 2. Spalte von M
				for(int j=0;j Zeile(N)
			for(int j=0;j Spalte(N)
		return N;
	static short[][] GFmatrixAdd(short[][] A,short[][] B){
		if(A.length!=B.length || A[0].length!=B[0].length)
			return null; //size mismatch
		for(int i=0;i

Generated on Fri Sep 24 10:39:12 CEST 2010