[Jcrypt-commits] JCrypt/cs199mbc/plugins RealPlayfair.java,NONE,1.1

[Simon F. <sim...@us...>]

Update of /cvsroot/jcrypt/JCrypt/cs199mbc/plugins
In directory sc8-pr-cvs1.sourceforge.net:/tmp/cvs-serv31974/cs199mbc/plugins

Added Files:
	RealPlayfair.java 
Log Message:
More Plugins!!!

--- NEW FILE: RealPlayfair.java ---
/*
 RealPlayfair Class
 Copyright (C) 2005 Silas Snider

 This program is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This program is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this program; if not, write to the Free Software
 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
package cs199mbc.plugins;

import cs199mbc.Machine;

public class RealPlayfair implements Machine {
	private boolean encoder = false;
	public static final String toName = "Playfair", toString = "Playfair";
	private char[][] square = new char[5][5];
	private String alpha = "ABCDEFGHIKLMNOPQRSTUVWXYZ";

	public String encode(String text) {
		boolean t = encoder;
		encoder = true;
		String temp = doStuff(text);
		encoder = t;
		return temp;
	}

	public String decode(String text) {
		boolean t = encoder;
		encoder = false;
		String temp = doStuff(text);
		encoder = t;
		return temp;
	}

	public void setOptionKeyword(String s) {
		s = s.toUpperCase();
		s = s.replace('J', 'I');
		int realLength = 0;
		for (int i = 0; i < s.length(); i++) { // Writes the keyword across the
			// top
			if (s.indexOf(s.charAt(i)) == i) {
				realLength++;
				square[i % 5][i / 5] = s.charAt(i);
			}
		}
		int j = 0;
		for (int i = realLength; i < 25; i++) {
			j++;
			if (s.indexOf(alpha.charAt(j)) != -1) {
				i--;
			} else {
				square[i % 5][i / 5] = alpha.charAt(j);
			}
		}
		for (int i = 0; i < 5; i++) {
			for (int k = 0; k < 5; k++) {
				System.out.print(square[k][i]);
			}
			System.out.println("");
		}
	}

	public void setOptionEncode(boolean b) {
		encoder = b;
	}

	private int findLetterIndex(char c) {
		int ret = -1;
		if (c == 'J')
			c = 'I';
		for (int i = 0; i < 25; i++) {
			if (square[i % 5][i / 5] == c) {
				ret = i;
			}
		}
		return ret;
	}

	private String elimWhite(String inp) {
		StringBuffer ret = new StringBuffer();
		for (int i = 0; i < inp.length(); i++) {
			if (Character.isWhitespace(inp.charAt(i))) {
				continue;
			}
			ret.append(inp.charAt(i));
		}
		return ret.toString();
	}

	public String doStuff(String s) {
		StringBuffer result = new StringBuffer();
		if (encoder) {
			s = elimWhite(s);
			s = s.toUpperCase();
			if ((s.length() % 2) != 0) {
				s = s + "X";
			}
			String digram;
			for (int i = 1; i < s.length(); i += 2) {
				if (s.charAt(i - 1) == s.charAt(i)) {
					if (s.charAt(i - 1) == 'X') {
						digram = s.charAt(i - 1) + "Q";
					} else {
						digram = s.charAt(i - 1) + "X";
					}
					i--;
				} else {
					digram = ("" + s.charAt(i - 1)) + s.charAt(i);
				}
				int[] ind = findDigramIndices(digram);
				char[] ret = new char[2];
				if ((ind[0] / 5) == (ind[1] / 5)) {
					if ((ind[0] % 5) == 4) {
						ind[0] = ind[0] - 4;
					} else {
						ind[0]++;
					}
					if ((ind[1] % 5) == 4) {
						ind[1] = ind[1] - 4;
					} else {
						ind[1]++;
					}
					ret[0] = square[ind[0] % 5][ind[0] / 5];
					ret[1] = square[ind[1] % 5][ind[1] / 5];
				} else if ((ind[0] % 5) == (ind[1] % 5)) {
					ind[0] = (ind[0] + 5) % 25;
					ind[1] = (ind[1] + 5) % 25;
					ret[0] = square[ind[0] % 5][ind[0] / 5];
					ret[1] = square[ind[1] % 5][ind[1] / 5];
				} else {
					ret[0] = square[ind[0] % 5][ind[1] / 5];
					ret[1] = square[ind[1] % 5][ind[0] / 5];
				}
				result.append(ret[0]);
				result.append(ret[1]);
				result.append(" ");
			}
		} else {
			s = elimWhite(s);
			s = s.toUpperCase();
			if ((s.length() % 2) != 0) {
				s = s + "X";
			}
			String digram;
			for (int i = 1; i < s.length(); i += 2) {
				if (s.charAt(i - 1) == s.charAt(i)) {
					if (s.charAt(i - 1) == 'X') {
						digram = s.charAt(i - 1) + "Q";
					} else {
						digram = s.charAt(i - 1) + "X";
					}
					i--;
				} else {
					digram = ("" + s.charAt(i - 1)) + s.charAt(i);
				}
				int[] ind = findDigramIndices(digram);
				char[] ret = new char[2];
				if ((ind[0] / 5) == (ind[1] / 5)) {
					if ((ind[0] % 5) == 0) {
						ind[0] = ind[0] + 4;
					} else {
						ind[0]--;
					}
					if ((ind[1] % 5) == 0) {
						ind[1] = ind[1] + 4;
					} else {
						ind[1]--;
					}
					ret[0] = square[ind[0] % 5][ind[0] / 5];
					ret[1] = square[ind[1] % 5][ind[1] / 5];
				} else if ((ind[0] % 5) == (ind[1] % 5)) {
					if ((ind[0] - 5) < 0) {
						ind[0] += 25;
					}
					if ((ind[1] - 5) < 0) {
						ind[1] += 25;
					}
					ind[0] = (ind[0] - 5) % 25;
					ind[1] = (ind[1] - 5) % 25;
					ret[0] = square[ind[0] % 5][ind[0] / 5];
					ret[1] = square[ind[1] % 5][ind[1] / 5];
				} else {
					ret[0] = square[ind[0] % 5][ind[1] / 5];
					ret[1] = square[ind[1] % 5][ind[0] / 5];
				}
				result.append(ret[0]);
				result.append(ret[1]);
				result.append(" ");
			}
		}
		return result.toString();
	}

	private int[] findDigramIndices(String digram) {
		int[] ret = new int[2];
		ret[0] = findLetterIndex(digram.charAt(0));
		ret[1] = findLetterIndex(digram.charAt(1));
		return ret;
	}

}