Base91 encode, decode https://github.com/mscdex/base91.js ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,./:;<=>?@[]^_`{|}~"

Base91.js

(function() {
    var hasNode = (typeof process !== 'undefined' && process.versions && process.versions.node),
        hasTypedArray = (typeof Uint8Array !== 'undefined');
    if (hasNode && require('fs').existsSync(__dirname + '/../build/Release/base91encdec.node')) {
        module.exports = require(__dirname + '/../build/Release/base91encdec.node');
        return;
    }
    var AVERAGE_ENCODING_RATIO = 1.2297,
        ENCODING_TABLE = [
            'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N',
            'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z',
            'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j', 'k', 'l', 'm', 'n',
            'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z',
            '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
            '!', '#', '$', '%', '&', '(', ')', '*', '+', ',', '.', '/', ':', ';',
            '<', '=', '>', '?', '@', '[', ']', '^', '_', '`', '{', '|', '}', '~',
            '"'
        ],
        DECODING_TABLE = [
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 62, 90, 63, 64, 65, 66, 91, 67, 68, 69, 70, 71, 91, 72, 73,
            52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 74, 75, 76, 77, 78, 79,
            80, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
            15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 81, 91, 82, 83, 84,
            85, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
            41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 86, 87, 88, 89, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91,
            91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91, 91
        ];

    var i = 0;

    var base91 = {
        encode: function(data) {
            var len = data.length,
                output = '',
                ebq = 0,
                en = 0,
                ev = 0,
                j = 0,
                byte = 0;

            if (typeof data === 'string') {
                for (i = 0; i < len; ++i) {
                    byte = data.charCodeAt(i);
                    j = 0;
                    var lenj = (byte < 128 ? 1 : (byte > 127 && byte < 2048 ? 2 : 3));
                    for (; j < lenj; ++j) {
                        if (lenj === 1)
                            ebq |= byte << en;
                        else if (lenj === 2) {
                            if (j === 0)
                                ebq |= ((byte >> 6) | 192) << en;
                            else
                                ebq |= ((byte & 63) | 128) << en;
                        } else {
                            if (j === 0)
                                ebq |= ((byte >> 12) | 224) << en;
                            else if (j === 1)
                                ebq |= (((byte >> 6) & 63) | 128) << en;
                            else
                                ebq |= ((byte & 63) | 128) << en;
                        }
                        en += 8;
                        if (en > 13) {
                            ev = ebq & 8191;
                            if (ev > 88) {
                                ebq >>= 13;
                                en -= 13;
                            } else {
                                ev = ebq & 16383;
                                ebq >>= 14;
                                en -= 14;
                            }
                            output += ENCODING_TABLE[ev % 91];
                            output += ENCODING_TABLE[(ev / 91) | 0];
                        }
                    }
                }
            } else {
                for (i = 0; i < len; ++i) {
                    ebq |= (data[i] & 255) << en;
                    en += 8;
                    if (en > 13) {
                        ev = ebq & 8191;
                        if (ev > 88) {
                            ebq >>= 13;
                            en -= 13;
                        } else {
                            ev = ebq & 16383;
                            ebq >>= 14;
                            en -= 14;
                        }
                        output += ENCODING_TABLE[ev % 91];
                        output += ENCODING_TABLE[(ev / 91) | 0];
                    }
                }
            }

            if (en > 0) {
                output += ENCODING_TABLE[ebq % 91];
                if (en > 7 || ebq > 90)
                    output += ENCODING_TABLE[(ebq / 91) | 0];
            }

            return output;
        },
        decode: function(data) {
            var len = data.length,
                estimatedSize = ((len / AVERAGE_ENCODING_RATIO) | 0),
                dbq = 0,
                dn = 0,
                dv = -1,
                i = 0,
                o = -1,
                byte = 0,
                output = new Array(estimatedSize);

            if (typeof data === 'string') {
                for (i = 0; i < len; ++i) {
                    byte = data.charCodeAt(i);
                    if (DECODING_TABLE[byte] === 91)
                        continue;
                    if (dv === -1)
                        dv = DECODING_TABLE[byte];
                    else {
                        dv += DECODING_TABLE[byte] * 91;
                        dbq |= dv << dn;
                        dn += ((dv & 8191) > 88 ? 13 : 14);
                        do {
                            if (++o >= estimatedSize)
                                output.push(dbq & 0xFF);
                            else
                                output[o] = dbq & 0xFF;
                            dbq >>= 8;
                            dn -= 8;
                        } while (dn > 7);
                        dv = -1;
                    }
                }
            } else {
                for (i = 0; i < len; ++i) {
                    byte = data[i];
                    if (DECODING_TABLE[byte] === 91)
                        continue;
                    if (dv === -1)
                        dv = DECODING_TABLE[byte];
                    else {
                        dv += DECODING_TABLE[byte] * 91;
                        dbq |= dv << dn;
                        dn += ((dv & 8191) > 88 ? 13 : 14);
                        do {
                            if (++o >= estimatedSize)
                                output.push(dbq & 0xFF);
                            else
                                output[o] = dbq & 0xFF;
                            dbq >>= 8;
                            dn -= 8;
                        } while (dn > 7);
                        dv = -1;
                    }
                }
            }

            if (dv !== -1) {
                if (++o >= estimatedSize)
                    output.push(dbq | dv << dn);
                else
                    output[o] = (dbq | dv << dn);
            }

            if (o > -1 && o < estimatedSize - 1)
                output = output.slice(0, o + 1);

            var ret;
            if (hasNode)
                ret = new Buffer(output);
            else if (hasTypedArray) {
                ret = new Uint8Array(output.length);
                for (i = 0, len = output.length; i < len; ++i)
                    ret[i] = output[i];
            } else
                ret = output;

            return ret;
        }
    };

    if (hasNode)
        module.exports = base91;
    else
        window.base91 = base91;
})();