/*
* Copyright WizTools.org
* Licensed under the Apache License, Version 2.0:
* http://www.apache.org/licenses/LICENSE-2.0
*/
//package org.wiztools.commons;
import java.util.Collections;
import java.util.HashMap;
import java.util.Map;
/**
* An implementation of the ROT-13 algorithm. The lookup table is defined as a
* constant in the code: making this implementation pretty fast.
* @author subhash
*/
public final class Rot13 {
private static final Map<Character, Character> map;
static {
final char[] lookup1 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz".toCharArray();
final char[] lookup2 = "NOPQRSTUVWXYZABCDEFGHIJKLMnopqrstuvwxyzabcdefghijklm".toCharArray();
Map<Character, Character> m = new HashMap<Character, Character>();
for(int i=0; i<lookup1.length; i++) {
m.put(lookup1[i], lookup2[i]);
}
map = Collections.unmodifiableMap(m);
}
private Rot13() {}
/**
* Converts the input string ROT-13 algorithm.
* @param inStr The input string.
* @return The ROT-13ed version of the input string.
*/
public static String cipher(final String inStr) {
char[] arr = inStr.toCharArray();
StringBuilder sb = new StringBuilder(arr.length);
for(char c: arr) {
Character out = map.get(c);
if(out == null) {
sb.append(c);
}
else {
sb.append(out);
}
}
return sb.toString();
}
}
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