package jp.sourceforge.qrcode.ecc;public class BCH15_5 {	int[][] gf16;	boolean[] receiveData;	int numCorrectedError;	public BCH15_5(boolean[] source) {		gf16 = createGF16();		receiveData = source;		//printBit("receive data", receiveData);			}		public boolean[] correct() {		int[] s = calcSyndrome(receiveData);				int[] errorPos = detectErrorBitPosition(s);		boolean[] output = correctErrorBit(receiveData, errorPos);		return output;	}		int[][] createGF16() {		gf16 = new int[16][4];		int[] seed = {1, 1, 0, 0};		for (int i = 0; i < 4; i++)			gf16[i][i] = 1;		for (int i = 0; i < 4; i++)			gf16[4][i] = seed[i];		for (int i = 5; i < 16; i++) {			for (int j = 1; j < 4; j++) {				gf16[i][j] = gf16[i - 1][j - 1];			}			if (gf16[i - 1][3] == 1) {				for (int j = 0; j < 4; j++)					gf16[i][j] = (gf16[i][j] + seed[j]) % 2;			}		}		return gf16;	}		int searchElement(int[] x) {		int k;		for (k = 0; k < 15; k++) {			if (   x[0] == gf16[k][0]					&& x[1] == gf16[k][1]					&& x[2] == gf16[k][2]			    && x[3] == gf16[k][3]				 ) break;		}		return k;	}	  /*String getInputString() {		String inputString = null;		InputStreamReader isr = new InputStreamReader(System.in);		BufferedReader br = new BufferedReader(isr);		try {			inputString = br.readLine();		} catch (IOException e){}		return inputString;  }*/  	/*public int getInput() {		System.out.print("Input Number 0-127: ");		String str = getInputString();		int input = Integer.parseInt(str);		return input;	}*/		int[] getCode(int input) {		int[] f = new int[15];		int[] r = new int[8];				for (int i = 0; i < 15; i++) {			//1 + x + x^3			int w1, w2;			int yin;						w1 = r[7];			if (i < 7) {				yin = (input >> (6 - i)) % 2;				w2 = (yin + w1) % 2;			}			else {				yin = w1;				w2 = 0;			}			r[7] = (r[6] + w2) % 2;			r[6] = (r[5] + w2) % 2;			r[5] = r[4];			r[4] = (r[3] + w2) % 2;			r[3] = r[2];			r[2] = r[1];			r[1] = r[0];			r[0] = w2;			f[14 - i] = yin;		}		return f;	}		static String[] bitName = {"c0", "c1", "c2","c3", "c4", "c5","c6", "c7", "c8", "c9", 															"d0", "d1", "d2", "d3", "d4", };	//  static void printBit(String title, boolean[] bit) {//		System.out.print(title+": ");//		for (int i = 0; i < 15; i++) {//			if (i == 5) System.out.print(" ");//			System.out.print((bit[14 - i] == true) ? "1" : "0" );				//		}//		System.out.print("  (");//		for (int i = 0; i < 15; i++) {//			if (i == 5) System.out.print(" ");//			System.out.print(bitName[14 - i]);				//		}//		System.out.println(")");//	}		int addGF(int arg1, int arg2) {				int[] p = new int[4];		for (int m = 0; m < 4; m++) {			int w1 = (arg1 < 0 || arg1 >= 15) ? 0 : gf16[arg1][m];			int w2 = (arg2 < 0 || arg2 >= 15) ? 0 : gf16[arg2][m];			p[m] = (w1 + w2) % 2;		}		return searchElement(p);	}	/*void addRandomError(boolean[] f) {		Random random = new Random();		random.setSeed(System.currentTimeMillis());				int r;		int numError = 3; //[TODO]change number of error and check				for (int i = 0; i < numError; i++) {			r = random.nextInt();			if (r < 0) r = -r;			if (r / (double)Integer.MAX_VALUE < 0.9) {				int errorPos = r % 15;				f[errorPos] = !f[errorPos];			}			}	}*/	int[] calcSyndrome(boolean[] y) {		int[] s = new int[5];		int[] p = new int[4];		int k;		for (k = 0; k < 15; k++) {			if (y[k] == true) for (int m = 0; m < 4; m++) 				p[m] = (p[m] + gf16[k][m]) % 2;		}		k = searchElement(p);		s[0] = (k >= 15)? -1 : k;		/*System.out.println("SyndromeS1 = " + ((s[0] == -1) ?				"0" : 				"α^" + String.valueOf(s[0]))		);*/				s[1] = (s[0] < 0) ? -1 : (s[0] * 2) % 15;		/*System.out.println("SyndromeS2 = " + ((s[1] == -1) ?				"0" : 				"α^" + String.valueOf(s[1]))		);*/				p = new int[4];		for (k = 0; k < 15; k++) {			if (y[k] == true) for (int m = 0; m < 4; m++) 				p[m] = (p[m] + gf16[(k * 3) % 15][m]) % 2;		}					k = searchElement(p);		s[2] = (k >= 15) ? -1 : k;		/*System.out.println("SyndromeS3 = " + ((s[2] == -1) ?				"0" : 				"α^" + String.valueOf(s[2]))		);*/				s[3] = (s[1] < 0) ? -1 : (s[1] * 2) % 15;		/*System.out.println("SyndromeS4 = " + ((s[3] == -1) ?				"0" : 				"α^" + String.valueOf(s[3]))		);*/				p = new int[4];		for (k = 0; k < 15; k++) {			if (y[k] == true) for (int m = 0; m < 4; m++) 				p[m] = (p[m] + gf16[(k * 5) % 15][m]) % 2; 		}		k = searchElement(p);		s[4] = (k >= 15)? -1 : k;		/*System.out.println("SyndromeS5 = " + ((s[4] == -1) ?				"0" : 				"α^" + String.valueOf(s[4]))		);*/				return s;	}		int[] calcErrorPositionVariable(int[] s) {		int[] e = new int[4];		// calc σ1		e[0] = s[0];		//System.out.println("σ1 = " + String.valueOf(e[0]));				// calc σ2		int t = (s[0] + s[1]) % 15;		int mother = addGF(s[2], t);		mother = (mother >= 15) ? -1 : mother;				t = (s[2] + s[1]) % 15;		int child = addGF(s[4], t);		child = (child >= 15) ? -1 : child;		e[1] = (child < 0 && mother < 0) ? -1 : (child - mother + 15) % 15;				//System.out.println("σ2 = " + String.valueOf(e[1]));				// calc σ3		t = (s[1] + e[0]) % 15;		int t1 = addGF(s[2], t);		t = (s[0] + e[1]) % 15;		e[2] = addGF(t1, t);		//System.out.println("σ3 = " + String.valueOf(e[2]));				return e;	}		int[] detectErrorBitPosition(int[] s) {				int[] e = calcErrorPositionVariable(s);		int[] errorPos = new int[4];		if (e[0] == -1) {			//System.out.println("No errors.");			return errorPos;		}		else if (e[1] == -1) {			/*System.out.println("1 error. position is "+ 					String.valueOf(e[0]) +					" (" + bitName[e[0]] + ")")*/;			errorPos[0] = 1;			errorPos[1] = e[0];			return errorPos;		}		//else {			//System.out.println("2 or more errors.");					//}		//int numError = 0;		//int[] p;		int x3, x2, x1;		int t, t1, t2, anError;		//error detection		for (int i = 0; i < 15; i++) {			//calc x^3 + σ1*x^2 + σ2*x + σ3 = 0			x3 = (i * 3) % 15;			x2 = (i * 2) % 15;			x1 = i;						//p = new int[4];						t = (e[0] + x2) % 15;			t1 = addGF(x3, t);						t = (e[1] + x1) % 15;			t2 = addGF(t, e[2]);						anError = addGF(t1,t2);						if (anError >= 15) {				/*System.out.println("Error found. position is " + 						String.valueOf(i) +						"(" + bitName[i]+ ")");*/				errorPos[0]++;				errorPos[errorPos[0]] = i;			}		}				return errorPos;	}		boolean[] correctErrorBit(boolean[] y, int[] errorPos) {		//errorPos[0]にエラーの數(shù)、errorPos[1],[2],[3]に実際の位置が入っている		for (int i = 1; i <= errorPos[0]; i++)			y[errorPos[i]] = !y[errorPos[i]];				numCorrectedError = errorPos[0];		//printBit("Collected data", y);		return y;	}		public int getNumCorrectedError() {		return numCorrectedError;	}	  /*boolean[] parseBooleanArray(String source)  {      int i = Integer.parseInt(source, 2);      boolean b[] = new boolean[source.length()];      for(int j = 0; j < 15; j++)      {          int t = i >> j & 1;          if(t == 1)              b[j] = true;          else              b[j] = false;      }      return b;  }*/}