source: imaps-frontend/node_modules/punycode/punycode.js

'use strict';

/** Highest positive signed 32-bit float value */
const maxInt = 2147483647; // aka. 0x7FFFFFFF or 2^31-1

/** Bootstring parameters */
const base = 36;
const tMin = 1;
const tMax = 26;
const skew = 38;
const damp = 700;
const initialBias = 72;
const initialN = 128; // 0x80
const delimiter = '-'; // '\x2D'

/** Regular expressions */
const regexPunycode = /^xn--/;
const regexNonASCII = /[^\0-\x7F]/; // Note: U+007F DEL is excluded too.
const regexSeparators = /[\x2E\u3002\uFF0E\uFF61]/g; // RFC 3490 separators

/** Error messages */
const errors = {
        'overflow': 'Overflow: input needs wider integers to process',
        'not-basic': 'Illegal input >= 0x80 (not a basic code point)',
        'invalid-input': 'Invalid input'
};

/** Convenience shortcuts */
const baseMinusTMin = base - tMin;
const floor = Math.floor;
const stringFromCharCode = String.fromCharCode;

/*--------------------------------------------------------------------------*/

/**
 * A generic error utility function.
 * @private
 * @param {String} type The error type.
 * @returns {Error} Throws a `RangeError` with the applicable error message.
 */
function error(type) {
        throw new RangeError(errors[type]);
}

/**
 * A generic `Array#map` utility function.
 * @private
 * @param {Array} array The array to iterate over.
 * @param {Function} callback The function that gets called for every array
 * item.
 * @returns {Array} A new array of values returned by the callback function.
 */
function map(array, callback) {
        const result = [];
        let length = array.length;
        while (length--) {
                result[length] = callback(array[length]);
        }
        return result;
}

/**
 * A simple `Array#map`-like wrapper to work with domain name strings or email
 * addresses.
 * @private
 * @param {String} domain The domain name or email address.
 * @param {Function} callback The function that gets called for every
 * character.
 * @returns {String} A new string of characters returned by the callback
 * function.
 */
function mapDomain(domain, callback) {
        const parts = domain.split('@');
        let result = '';
        if (parts.length > 1) {
                // In email addresses, only the domain name should be punycoded. Leave
                // the local part (i.e. everything up to `@`) intact.
                result = parts[0] + '@';
                domain = parts[1];
        }
        // Avoid `split(regex)` for IE8 compatibility. See #17.
        domain = domain.replace(regexSeparators, '\x2E');
        const labels = domain.split('.');
        const encoded = map(labels, callback).join('.');
        return result + encoded;
}

/**
 * Creates an array containing the numeric code points of each Unicode
 * character in the string. While JavaScript uses UCS-2 internally,
 * this function will convert a pair of surrogate halves (each of which
 * UCS-2 exposes as separate characters) into a single code point,
 * matching UTF-16.
 * @see `punycode.ucs2.encode`
 * @see <https://mathiasbynens.be/notes/javascript-encoding>
 * @memberOf punycode.ucs2
 * @name decode
 * @param {String} string The Unicode input string (UCS-2).
 * @returns {Array} The new array of code points.
 */
function ucs2decode(string) {
        const output = [];
        let counter = 0;
        const length = string.length;
        while (counter < length) {
                const value = string.charCodeAt(counter++);
                if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
                        // It's a high surrogate, and there is a next character.
                        const extra = string.charCodeAt(counter++);
                        if ((extra & 0xFC00) == 0xDC00) { // Low surrogate.
                                output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
                        } else {
                                // It's an unmatched surrogate; only append this code unit, in case the
                                // next code unit is the high surrogate of a surrogate pair.
                                output.push(value);
                                counter--;
                        }
                } else {
                        output.push(value);
                }
        }
        return output;
}

/**
 * Creates a string based on an array of numeric code points.
 * @see `punycode.ucs2.decode`
 * @memberOf punycode.ucs2
 * @name encode
 * @param {Array} codePoints The array of numeric code points.
 * @returns {String} The new Unicode string (UCS-2).
 */
const ucs2encode = codePoints => String.fromCodePoint(...codePoints);

/**
 * Converts a basic code point into a digit/integer.
 * @see `digitToBasic()`
 * @private
 * @param {Number} codePoint The basic numeric code point value.
 * @returns {Number} The numeric value of a basic code point (for use in
 * representing integers) in the range `0` to `base - 1`, or `base` if
 * the code point does not represent a value.
 */
const basicToDigit = function(codePoint) {
        if (codePoint >= 0x30 && codePoint < 0x3A) {
                return 26 + (codePoint - 0x30);
        }
        if (codePoint >= 0x41 && codePoint < 0x5B) {
                return codePoint - 0x41;
        }
        if (codePoint >= 0x61 && codePoint < 0x7B) {
                return codePoint - 0x61;
        }
        return base;
};

/**
 * Converts a digit/integer into a basic code point.
 * @see `basicToDigit()`
 * @private
 * @param {Number} digit The numeric value of a basic code point.
 * @returns {Number} The basic code point whose value (when used for
 * representing integers) is `digit`, which needs to be in the range
 * `0` to `base - 1`. If `flag` is non-zero, the uppercase form is
 * used; else, the lowercase form is used. The behavior is undefined
 * if `flag` is non-zero and `digit` has no uppercase form.
 */
const digitToBasic = function(digit, flag) {
        //  0..25 map to ASCII a..z or A..Z
        // 26..35 map to ASCII 0..9
        return digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5);
};

/**
 * Bias adaptation function as per section 3.4 of RFC 3492.
 * https://tools.ietf.org/html/rfc3492#section-3.4
 * @private
 */
const adapt = function(delta, numPoints, firstTime) {
        let k = 0;
        delta = firstTime ? floor(delta / damp) : delta >> 1;
        delta += floor(delta / numPoints);
        for (/* no initialization */; delta > baseMinusTMin * tMax >> 1; k += base) {
                delta = floor(delta / baseMinusTMin);
        }
        return floor(k + (baseMinusTMin + 1) * delta / (delta + skew));
};

/**
 * Converts a Punycode string of ASCII-only symbols to a string of Unicode
 * symbols.
 * @memberOf punycode
 * @param {String} input The Punycode string of ASCII-only symbols.
 * @returns {String} The resulting string of Unicode symbols.
 */
const decode = function(input) {
        // Don't use UCS-2.
        const output = [];
        const inputLength = input.length;
        let i = 0;
        let n = initialN;
        let bias = initialBias;

        // Handle the basic code points: let `basic` be the number of input code
        // points before the last delimiter, or `0` if there is none, then copy
        // the first basic code points to the output.

        let basic = input.lastIndexOf(delimiter);
        if (basic < 0) {
                basic = 0;
        }

        for (let j = 0; j < basic; ++j) {
                // if it's not a basic code point
                if (input.charCodeAt(j) >= 0x80) {
                        error('not-basic');
                }
                output.push(input.charCodeAt(j));
        }

        // Main decoding loop: start just after the last delimiter if any basic code
        // points were copied; start at the beginning otherwise.

        for (let index = basic > 0 ? basic + 1 : 0; index < inputLength; /* no final expression */) {

                // `index` is the index of the next character to be consumed.
                // Decode a generalized variable-length integer into `delta`,
                // which gets added to `i`. The overflow checking is easier
                // if we increase `i` as we go, then subtract off its starting
                // value at the end to obtain `delta`.
                const oldi = i;
                for (let w = 1, k = base; /* no condition */; k += base) {

                        if (index >= inputLength) {
                                error('invalid-input');
                        }

                        const digit = basicToDigit(input.charCodeAt(index++));

                        if (digit >= base) {
                                error('invalid-input');
                        }
                        if (digit > floor((maxInt - i) / w)) {
                                error('overflow');
                        }

                        i += digit * w;
                        const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);

                        if (digit < t) {
                                break;
                        }

                        const baseMinusT = base - t;
                        if (w > floor(maxInt / baseMinusT)) {
                                error('overflow');
                        }

                        w *= baseMinusT;

                }

                const out = output.length + 1;
                bias = adapt(i - oldi, out, oldi == 0);

                // `i` was supposed to wrap around from `out` to `0`,
                // incrementing `n` each time, so we'll fix that now:
                if (floor(i / out) > maxInt - n) {
                        error('overflow');
                }

                n += floor(i / out);
                i %= out;

                // Insert `n` at position `i` of the output.
                output.splice(i++, 0, n);

        }

        return String.fromCodePoint(...output);
};

/**
 * Converts a string of Unicode symbols (e.g. a domain name label) to a
 * Punycode string of ASCII-only symbols.
 * @memberOf punycode
 * @param {String} input The string of Unicode symbols.
 * @returns {String} The resulting Punycode string of ASCII-only symbols.
 */
const encode = function(input) {
        const output = [];

        // Convert the input in UCS-2 to an array of Unicode code points.
        input = ucs2decode(input);

        // Cache the length.
        const inputLength = input.length;

        // Initialize the state.
        let n = initialN;
        let delta = 0;
        let bias = initialBias;

        // Handle the basic code points.
        for (const currentValue of input) {
                if (currentValue < 0x80) {
                        output.push(stringFromCharCode(currentValue));
                }
        }

        const basicLength = output.length;
        let handledCPCount = basicLength;

        // `handledCPCount` is the number of code points that have been handled;
        // `basicLength` is the number of basic code points.

        // Finish the basic string with a delimiter unless it's empty.
        if (basicLength) {
                output.push(delimiter);
        }

        // Main encoding loop:
        while (handledCPCount < inputLength) {

                // All non-basic code points < n have been handled already. Find the next
                // larger one:
                let m = maxInt;
                for (const currentValue of input) {
                        if (currentValue >= n && currentValue < m) {
                                m = currentValue;
                        }
                }

                // Increase `delta` enough to advance the decoder's <n,i> state to <m,0>,
                // but guard against overflow.
                const handledCPCountPlusOne = handledCPCount + 1;
                if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {
                        error('overflow');
                }

                delta += (m - n) * handledCPCountPlusOne;
                n = m;

                for (const currentValue of input) {
                        if (currentValue < n && ++delta > maxInt) {
                                error('overflow');
                        }
                        if (currentValue === n) {
                                // Represent delta as a generalized variable-length integer.
                                let q = delta;
                                for (let k = base; /* no condition */; k += base) {
                                        const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
                                        if (q < t) {
                                                break;
                                        }
                                        const qMinusT = q - t;
                                        const baseMinusT = base - t;
                                        output.push(
                                                stringFromCharCode(digitToBasic(t + qMinusT % baseMinusT, 0))
                                        );
                                        q = floor(qMinusT / baseMinusT);
                                }

                                output.push(stringFromCharCode(digitToBasic(q, 0)));
                                bias = adapt(delta, handledCPCountPlusOne, handledCPCount === basicLength);
                                delta = 0;
                                ++handledCPCount;
                        }
                }

                ++delta;
                ++n;

        }
        return output.join('');
};

/**
 * Converts a Punycode string representing a domain name or an email address
 * to Unicode. Only the Punycoded parts of the input will be converted, i.e.
 * it doesn't matter if you call it on a string that has already been
 * converted to Unicode.
 * @memberOf punycode
 * @param {String} input The Punycoded domain name or email address to
 * convert to Unicode.
 * @returns {String} The Unicode representation of the given Punycode
 * string.
 */
const toUnicode = function(input) {
        return mapDomain(input, function(string) {
                return regexPunycode.test(string)
                        ? decode(string.slice(4).toLowerCase())
                        : string;
        });
};

/**
 * Converts a Unicode string representing a domain name or an email address to
 * Punycode. Only the non-ASCII parts of the domain name will be converted,
 * i.e. it doesn't matter if you call it with a domain that's already in
 * ASCII.
 * @memberOf punycode
 * @param {String} input The domain name or email address to convert, as a
 * Unicode string.
 * @returns {String} The Punycode representation of the given domain name or
 * email address.
 */
const toASCII = function(input) {
        return mapDomain(input, function(string) {
                return regexNonASCII.test(string)
                        ? 'xn--' + encode(string)
                        : string;
        });
};

/*--------------------------------------------------------------------------*/

/** Define the public API */
const punycode = {
        /**
         * A string representing the current Punycode.js version number.
         * @memberOf punycode
         * @type String
         */
        'version': '2.3.1',
        /**
         * An object of methods to convert from JavaScript's internal character
         * representation (UCS-2) to Unicode code points, and back.
         * @see <https://mathiasbynens.be/notes/javascript-encoding>
         * @memberOf punycode
         * @type Object
         */
        'ucs2': {
                'decode': ucs2decode,
                'encode': ucs2encode
        },
        'decode': decode,
        'encode': encode,
        'toASCII': toASCII,
        'toUnicode': toUnicode
};

module.exports = punycode;