Class Base32

CodenameOne/src/com/codename1/security/Base32.java:35–117

/// String enc    = Base32.encode(secret);
/// ```
public final class Base32 {
    private Base32() {}

    private static final char[] ALPHABET =
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567".toCharArray();
    private static final int[] DECODE = new int[128];
    static {
        for (int i = 0; i < DECODE.length; i++) {
            DECODE[i] = -1;
        }
        for (int i = 0; i < ALPHABET.length; i++) {
            DECODE[ALPHABET[i]] = i;
        }
        // common lowercase variant
        for (int i = 0; i < ALPHABET.length; i++) {
            char lc = (char) (ALPHABET[i] | 0x20);
            if (lc != ALPHABET[i]) {
                DECODE[lc] = i;
            }
        }
    }

    /// Encodes the bytes as a Base32 string (uppercase, with `=` padding).
    public static String encode(byte[] data) {
        if (data == null || data.length == 0) {
            return "";
        }
        int output = ((data.length + 4) / 5) * 8;
        StringBuilder b = new StringBuilder(output);
        int bits = 0;
        int value = 0;
        for (byte aData : data) {
            value = (value << 8) | (aData & 0xff);
            bits += 8;
            while (bits >= 5) {
                b.append(ALPHABET[(value >>> (bits - 5)) & 0x1f]);
                bits -= 5;
            }
        }
        if (bits > 0) {
            b.append(ALPHABET[(value << (5 - bits)) & 0x1f]);
        }
        while (b.length() < output) {
            b.append('=');
        }
        return b.toString();
    }

    /// Decodes a Base32 string. Padding and whitespace are tolerated; mixed
    /// case is accepted.
    public static byte[] decode(String s) {
        if (s == null) {
            return new byte[0];
        }
        // strip padding and whitespace
        StringBuilder cleaned = new StringBuilder(s.length());
        for (int i = 0; i < s.length(); i++) {
            char c = s.charAt(i);