Viewing github.com/alecthomas/chroma/cmd/chromad/static/base64.js

```
/**
```
```
 *  base64.ts
```
```
 *
```

 *  Licensed under the BSD 3-Clause License.

 *    http://opensource.org/licenses/BSD-3-Clause

```
 *
```
```
 *  References:
```

 *    http://en.wikipedia.org/wiki/Base64

```
 *
```

 * @author Dan Kogai (https://github.com/dankogai)

```
 */
```
```
const version = '3.7.4';
```
```
/**
```

 * @deprecated use lowercase `version`.

```
 */
```
```
const VERSION = version;
```

const _hasatob = typeof atob === 'function';

const _hasbtoa = typeof btoa === 'function';

const _hasBuffer = typeof Buffer === 'function';

const _TD = typeof TextDecoder === 'function' ? new TextDecoder() : undefined;

const _TE = typeof TextEncoder === 'function' ? new TextEncoder() : undefined;

const b64ch = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=';

const b64chs = Array.prototype.slice.call(b64ch);

```
const b64tab = ((a) => {
```
```
    let tab = {};
```
```
    a.forEach((c, i) => tab[c] = i);
```
```
    return tab;
```
```
})(b64chs);
```

const b64re = /^(?:[A-Za-z\d+\/]{4})*?(?:[A-Za-z\d+\/]{2}(?:==)?|[A-Za-z\d+\/]{3}=?)?$/;

const _fromCC = String.fromCharCode.bind(String);

const _U8Afrom = typeof Uint8Array.from === 'function'

```
    ? Uint8Array.from.bind(Uint8Array)
```

    : (it, fn = (x) => x) => new Uint8Array(Array.prototype.slice.call(it, 0).map(fn));

```
const _mkUriSafe = (src) => src
```

    .replace(/=/g, '').replace(/[+\/]/g, (m0) => m0 == '+' ? '-' : '_');

const _tidyB64 = (s) => s.replace(/[^A-Za-z0-9\+\/]/g, '');

```
/**
```
```
 * polyfill version of `btoa`
```
```
 */
```
```
const btoaPolyfill = (bin) => {
```
```
    // console.log('polyfilled');
```
```
    let u32, c0, c1, c2, asc = '';
```
```
    const pad = bin.length % 3;
```
```
    for (let i = 0; i < bin.length;) {
```

        if ((c0 = bin.charCodeAt(i++)) > 255 ||

            (c1 = bin.charCodeAt(i++)) > 255 ||

            (c2 = bin.charCodeAt(i++)) > 255)

            throw new TypeError('invalid character found');

        u32 = (c0 << 16) | (c1 << 8) | c2;

```
        asc += b64chs[u32 >> 18 & 63]
```
```
            + b64chs[u32 >> 12 & 63]
```
```
            + b64chs[u32 >> 6 & 63]
```
```
            + b64chs[u32 & 63];
```
```
    }
```

    return pad ? asc.slice(0, pad - 3) + "===".substring(pad) : asc;

```
};
```
```
/**
```

 * does what `window.btoa` of web browsers do.

```
 * @param {String} bin binary string
```

 * @returns {string} Base64-encoded string

```
 */
```

const _btoa = _hasbtoa ? (bin) => btoa(bin)

    : _hasBuffer ? (bin) => Buffer.from(bin, 'binary').toString('base64')

```
        : btoaPolyfill;
```
```
const _fromUint8Array = _hasBuffer
```

    ? (u8a) => Buffer.from(u8a).toString('base64')

```
    : (u8a) => {
```

        // cf. https://stackoverflow.com/questions/12710001/how-to-convert-uint8-array-to-base64-encoded-string/12713326#12713326

```
        const maxargs = 0x1000;
```
```
        let strs = [];
```

        for (let i = 0, l = u8a.length; i < l; i += maxargs) {

            strs.push(_fromCC.apply(null, u8a.subarray(i, i + maxargs)));

```
        }
```
```
        return _btoa(strs.join(''));
```
```
    };
```
```
/**
```

 * converts a Uint8Array to a Base64 string.

 * @param {boolean} [urlsafe] URL-and-filename-safe a la RFC4648 §5

```
 * @returns {string} Base64 string
```
```
 */
```

const fromUint8Array = (u8a, urlsafe = false) => urlsafe ? _mkUriSafe(_fromUint8Array(u8a)) : _fromUint8Array(u8a);

// This trick is found broken https://github.com/dankogai/js-base64/issues/130

// const utob = (src: string) => unescape(encodeURIComponent(src));

```
// reverting good old fationed regexp
```
```
const cb_utob = (c) => {
```
```
    if (c.length < 2) {
```
```
        var cc = c.charCodeAt(0);
```
```
        return cc < 0x80 ? c
```

            : cc < 0x800 ? (_fromCC(0xc0 | (cc >>> 6))

                + _fromCC(0x80 | (cc & 0x3f)))

                : (_fromCC(0xe0 | ((cc >>> 12) & 0x0f))

                    + _fromCC(0x80 | ((cc >>> 6) & 0x3f))

                    + _fromCC(0x80 | (cc & 0x3f)));

```
    }
```
```
    else {
```
```
        var cc = 0x10000
```

            + (c.charCodeAt(0) - 0xD800) * 0x400

            + (c.charCodeAt(1) - 0xDC00);

        return (_fromCC(0xf0 | ((cc >>> 18) & 0x07))

            + _fromCC(0x80 | ((cc >>> 12) & 0x3f))

            + _fromCC(0x80 | ((cc >>> 6) & 0x3f))

            + _fromCC(0x80 | (cc & 0x3f)));

```
    }
```
```
};
```

const re_utob = /[\uD800-\uDBFF][\uDC00-\uDFFFF]|[^\x00-\x7F]/g;

```
/**
```

 * @deprecated should have been internal use only.

```
 * @param {string} src UTF-8 string
```
```
 * @returns {string} UTF-16 string
```
```
 */
```

const utob = (u) => u.replace(re_utob, cb_utob);

```
//
```
```
const _encode = _hasBuffer
```

    ? (s) => Buffer.from(s, 'utf8').toString('base64')

```
    : _TE
```

        ? (s) => _fromUint8Array(_TE.encode(s))

```
        : (s) => _btoa(utob(s));
```
```
/**
```

 * converts a UTF-8-encoded string to a Base64 string.

 * @param {boolean} [urlsafe] if `true` make the result URL-safe

```
 * @returns {string} Base64 string
```
```
 */
```

const encode = (src, urlsafe = false) => urlsafe

```
    ? _mkUriSafe(_encode(src))
```
```
    : _encode(src);
```
```
/**
```

 * converts a UTF-8-encoded string to URL-safe Base64 RFC4648 §5.

```
 * @returns {string} Base64 string
```
```
 */
```

const encodeURI = (src) => encode(src, true);

// This trick is found broken https://github.com/dankogai/js-base64/issues/130

// const btou = (src: string) => decodeURIComponent(escape(src));

```
// reverting good old fationed regexp
```

const re_btou = /[\xC0-\xDF][\x80-\xBF]|[\xE0-\xEF][\x80-\xBF]{2}|[\xF0-\xF7][\x80-\xBF]{3}/g;

```
const cb_btou = (cccc) => {
```
```
    switch (cccc.length) {
```
```
        case 4:
```

            var cp = ((0x07 & cccc.charCodeAt(0)) << 18)

                | ((0x3f & cccc.charCodeAt(1)) << 12)

                | ((0x3f & cccc.charCodeAt(2)) << 6)

                | (0x3f & cccc.charCodeAt(3)), offset = cp - 0x10000;

            return (_fromCC((offset >>> 10) + 0xD800)

                + _fromCC((offset & 0x3FF) + 0xDC00));

```
        case 3:
```

            return _fromCC(((0x0f & cccc.charCodeAt(0)) << 12)

                | ((0x3f & cccc.charCodeAt(1)) << 6)

                | (0x3f & cccc.charCodeAt(2)));

```
        default:
```

            return _fromCC(((0x1f & cccc.charCodeAt(0)) << 6)

                | (0x3f & cccc.charCodeAt(1)));

```
    }
```
```
};
```
```
/**
```

 * @deprecated should have been internal use only.

```
 * @param {string} src UTF-16 string
```
```
 * @returns {string} UTF-8 string
```
```
 */
```

const btou = (b) => b.replace(re_btou, cb_btou);

```
/**
```
```
 * polyfill version of `atob`
```
```
 */
```
```
const atobPolyfill = (asc) => {
```
```
    // console.log('polyfilled');
```
```
    asc = asc.replace(/\s+/g, '');
```
```
    if (!b64re.test(asc))
```

        throw new TypeError('malformed base64.');

    asc += '=='.slice(2 - (asc.length & 3));

```
    let u24, bin = '', r1, r2;
```
```
    for (let i = 0; i < asc.length;) {
```

        u24 = b64tab[asc.charAt(i++)] << 18

            | b64tab[asc.charAt(i++)] << 12

            | (r1 = b64tab[asc.charAt(i++)]) << 6

            | (r2 = b64tab[asc.charAt(i++)]);

        bin += r1 === 64 ? _fromCC(u24 >> 16 & 255)

            : r2 === 64 ? _fromCC(u24 >> 16 & 255, u24 >> 8 & 255)

                : _fromCC(u24 >> 16 & 255, u24 >> 8 & 255, u24 & 255);

```
    }
```
```
    return bin;
```
```
};
```
```
/**
```

 * does what `window.atob` of web browsers do.

 * @param {String} asc Base64-encoded string

```
 * @returns {string} binary string
```
```
 */
```

const _atob = _hasatob ? (asc) => atob(_tidyB64(asc))

    : _hasBuffer ? (asc) => Buffer.from(asc, 'base64').toString('binary')

```
        : atobPolyfill;
```
```
//
```
```
const _toUint8Array = _hasBuffer
```

    ? (a) => _U8Afrom(Buffer.from(a, 'base64'))

    : (a) => _U8Afrom(_atob(a), c => c.charCodeAt(0));

```
/**
```

 * converts a Base64 string to a Uint8Array.

```
 */
```

const toUint8Array = (a) => _toUint8Array(_unURI(a));

```
//
```
```
const _decode = _hasBuffer
```

    ? (a) => Buffer.from(a, 'base64').toString('utf8')

```
    : _TD
```

        ? (a) => _TD.decode(_toUint8Array(a))

```
        : (a) => btou(_atob(a));
```

const _unURI = (a) => _tidyB64(a.replace(/[-_]/g, (m0) => m0 == '-' ? '+' : '/'));

```
/**
```

 * converts a Base64 string to a UTF-8 string.

 * @param {String} src Base64 string.  Both normal and URL-safe are supported

```
 * @returns {string} UTF-8 string
```
```
 */
```

const decode = (src) => _decode(_unURI(src));

```
/**
```

 * check if a value is a valid Base64 string

 * @param {String} src a value to check

```
  */
```
```
const isValid = (src) => {
```
```
    if (typeof src !== 'string')
```
```
        return false;
```

    const s = src.replace(/\s+/g, '').replace(/={0,2}$/, '');

    return !/[^\s0-9a-zA-Z\+/]/.test(s) || !/[^\s0-9a-zA-Z\-_]/.test(s);

```
};
```
```
//
```
```
const _noEnum = (v) => {
```
```
    return {
```

        value: v, enumerable: false, writable: true, configurable: true

```
    };
```
```
};
```
```
/**
```

 * extend String.prototype with relevant methods

```
 */
```
```
const extendString = function () {
```

    const _add = (name, body) => Object.defineProperty(String.prototype, name, _noEnum(body));

    _add('fromBase64', function () { return decode(this); });

    _add('toBase64', function (urlsafe) { return encode(this, urlsafe); });

    _add('toBase64URI', function () { return encode(this, true); });

    _add('toBase64URL', function () { return encode(this, true); });

    _add('toUint8Array', function () { return toUint8Array(this); });

```
};
```
```
/**
```

 * extend Uint8Array.prototype with relevant methods

```
 */
```
```
const extendUint8Array = function () {
```

    const _add = (name, body) => Object.defineProperty(Uint8Array.prototype, name, _noEnum(body));

    _add('toBase64', function (urlsafe) { return fromUint8Array(this, urlsafe); });

    _add('toBase64URI', function () { return fromUint8Array(this, true); });

    _add('toBase64URL', function () { return fromUint8Array(this, true); });

```
};
```
```
/**
```

 * extend Builtin prototypes with relevant methods

```
 */
```
```
const extendBuiltins = () => {
```
```
    extendString();
```
```
    extendUint8Array();
```
```
};
```
```
const gBase64 = {
```
```
    version: version,
```
```
    VERSION: VERSION,
```
```
    atob: _atob,
```
```
    atobPolyfill: atobPolyfill,
```
```
    btoa: _btoa,
```
```
    btoaPolyfill: btoaPolyfill,
```
```
    fromBase64: decode,
```
```
    toBase64: encode,
```
```
    encode: encode,
```
```
    encodeURI: encodeURI,
```
```
    encodeURL: encodeURI,
```
```
    utob: utob,
```
```
    btou: btou,
```
```
    decode: decode,
```
```
    isValid: isValid,
```
```
    fromUint8Array: fromUint8Array,
```
```
    toUint8Array: toUint8Array,
```
```
    extendString: extendString,
```

    extendUint8Array: extendUint8Array,

```
    extendBuiltins: extendBuiltins,
```
```
};
```
```
// makecjs:CUT //
```
```
export { version };
```
```
export { VERSION };
```
```
export { _atob as atob };
```
```
export { atobPolyfill };
```
```
export { _btoa as btoa };
```
```
export { btoaPolyfill };
```
```
export { decode as fromBase64 };
```
```
export { encode as toBase64 };
```
```
export { utob };
```
```
export { encode };
```
```
export { encodeURI };
```
```
export { encodeURI as encodeURL };
```
```
export { btou };
```
```
export { decode };
```
```
export { isValid };
```
```
export { fromUint8Array };
```
```
export { toUint8Array };
```
```
export { extendString };
```
```
export { extendUint8Array };
```
```
export { extendBuiltins };
```
```
// and finally,
```
```
export { gBase64 as Base64 };
```