Homoglyphs directory.

Homoglyphs.java

import javax.annotation.Nullable;
import java.util.Arrays;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class Homoglyphs {

    private static final List<char[]> LIST = Arrays.asList(
            prepare("! ǃ ！"),
            prepare("\" ״ ″ ＂"),
            prepare("$ ＄"),
            prepare("% ％"),
            prepare("& ＆"),
            prepare("' ＇"),
            prepare("( ﹝ （"),
            prepare(") ﹞ ）"),
            prepare("{ ｛"),
            prepare("| ǀ ا ｜"),
            prepare("} ｝"),
            prepare("~ ⁓ ～"),
            prepare("* ⁎ ＊"),
            prepare("+ ＋"),
            prepare(", ‚ ，"),
            prepare("- ‐ \uD800 \uD991 －"),
            prepare(". ٠ ۔ ܁ ܂ ․ ‧ 。 ． ｡"),
            prepare("/ ̸ ⁄ ∕ ╱ ⫻ ⫽ ／ ﾉ"),
            prepare("1 I ا １"),
            prepare("2 ２"),
            prepare("3 ３ з З э Э"),
            prepare("4 ４ ч Ч"),
            prepare("5 ５"),
            prepare("6 ６ б"),
            prepare("7 \uD801 \uD887 ７"),
            prepare("8 Ց ８"),
            prepare("9 ９"),
            prepare(": ։ ܃ ܄ ∶ ꞉ ："),
            prepare("; ; ；"),
            prepare("< ‹ ＜"),
            prepare("= \uD800 \uD990 ＝"),
            prepare("> › ＞"),
            prepare("? ？"),
            prepare("@ ＠"),
            prepare("[ ［"),
            prepare("\\ ＼"),
            prepare("^ ＾"),
            prepare("_ ＿"),
            prepare("` ｀"),
            prepare("A a À Á Â Ã Ä Å à á â ã ä å ɑ Α α а Ꭺ Ａ ａ"),
            prepare("B b ß ʙ Β β В Ь Ᏼ ᛒ Ｂ ｂ ъ Ъ"),
            prepare("C c ϲ Ϲ С с Ꮯ Ⅽ ⅽ \uD801 \uD8A8 Ｃ ｃ"),
            prepare("D d Ď ď Đ đ ԁ ժ Ꭰ Ⅾ ⅾ Ｄ ｄ"),
            prepare("E e È É Ê Ë é ê ë Ē ē Ĕ ĕ Ė ė Ę Ě ě Ε Е е Ꭼ Ｅ ｅ ё Ё"),
            prepare("F f Ϝ Ｆ ｆ"),
            prepare("G g ɡ ɢ Ԍ ն Ꮐ Ｇ ｇ"),
            prepare("H h ʜ Η Н һ Ꮋ Ｈ ｈ"),
            prepare("I i l ɩ Ι І і ا Ꭵ ᛁ Ⅰ ⅰ \uD801 \uD883 Ｉ ｉ"),
            prepare("J j ϳ Ј ј յ Ꭻ Ｊ ｊ"),
            prepare("K k Κ κ К Ꮶ ᛕ K Ｋ ｋ"),
            prepare("L l ʟ ι ا Ꮮ Ⅼ ⅼ Ｌ ｌ"),
            prepare("M m Μ Ϻ М Ꮇ ᛖ Ⅿ ⅿ Ｍ ｍ"),
            prepare("N n ɴ Ν Ｎ ｎ"),
            prepare("O o 0 O o Ο ο О о Օ \uD801 \uD886 Ｏ ｏ ö Ö Ӧ"),
            prepare("P p Ρ ρ Р р Ꮲ Ｐ ｐ"),
            prepare("Q q Ⴍ Ⴓ Ｑ ｑ"),
            prepare("R r ʀ Ի Ꮢ ᚱ Ｒ ｒ г"),
            prepare("S s Ѕ ѕ Տ Ⴝ Ꮪ \uD801 \uD896 Ｓ ｓ"),
            prepare("T t Τ τ Т Ꭲ Ｔ ｔ"),
            prepare("U u μ υ Ա Ս ⋃ Ｕ ｕ"),
            prepare("V v ν Ѵ ѵ Ꮩ Ⅴ ⅴ Ｖ ｖ"),
            prepare("W w ѡ Ꮃ Ｗ ｗ"),
            prepare("X x Χ χ Х х Ⅹ ⅹ Ｘ ｘ"),
            prepare("Y y ʏ Υ γ у Ү Ｙ ｙ"),
            prepare("Z z Ζ Ꮓ Ｚ ｚ")
    );

    private static char[] prepare(String homoglyphs) {
        char[] chars = homoglyphs.toCharArray();
        final Set<Character> set = new HashSet<>();

        int newLen = 0;
        for (int i = 0; i < chars.length; i++) {
            final char ch = Character.toLowerCase(chars[i]);
            if (ch != ' ' && set.add(ch)) {
                chars[newLen++] = ch;
            }
        }
        if (newLen < chars.length) {
            final char[] newChars = new char[newLen];
            System.arraycopy(chars, 0, newChars, 0, newLen);
            chars = newChars;
        }

        Arrays.sort(chars);
        return chars;
    }

    @Nullable
    public static char[] getHomoglyphs(char charInLowerCase) {
        for (char[] chars : LIST) {
            final int i = Arrays.binarySearch(chars, charInLowerCase);
            if (i >= 0) {
                return chars;
            }
        }
        return null;
    }

    private static void printDebug() {
        for (char[] chars : LIST) {
            System.out.println("[" + new String(chars) + "]");
        }
    }
}