441 lines
12 KiB
JavaScript
441 lines
12 KiB
JavaScript
'use strict';
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/** Highest positive signed 32-bit float value */
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const maxInt = 2147483647; // aka. 0x7FFFFFFF or 2^31-1
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/** Bootstring parameters */
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const base = 36;
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const tMin = 1;
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const tMax = 26;
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const skew = 38;
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const damp = 700;
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const initialBias = 72;
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const initialN = 128; // 0x80
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const delimiter = '-'; // '\x2D'
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/** Regular expressions */
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const regexPunycode = /^xn--/;
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const regexNonASCII = /[^\0-\x7E]/; // non-ASCII chars
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const regexSeparators = /[\x2E\u3002\uFF0E\uFF61]/g; // RFC 3490 separators
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/** Error messages */
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const errors = {
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'overflow': 'Overflow: input needs wider integers to process',
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'not-basic': 'Illegal input >= 0x80 (not a basic code point)',
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'invalid-input': 'Invalid input'
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};
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/** Convenience shortcuts */
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const baseMinusTMin = base - tMin;
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const floor = Math.floor;
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const stringFromCharCode = String.fromCharCode;
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/*--------------------------------------------------------------------------*/
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/**
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* A generic error utility function.
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* @private
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* @param {String} type The error type.
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* @returns {Error} Throws a `RangeError` with the applicable error message.
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*/
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function error(type) {
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throw new RangeError(errors[type]);
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}
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/**
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* A generic `Array#map` utility function.
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* @private
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* @param {Array} array The array to iterate over.
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* @param {Function} callback The function that gets called for every array
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* item.
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* @returns {Array} A new array of values returned by the callback function.
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*/
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function map(array, fn) {
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const result = [];
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let length = array.length;
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while (length--) {
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result[length] = fn(array[length]);
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}
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return result;
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}
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/**
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* A simple `Array#map`-like wrapper to work with domain name strings or email
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* addresses.
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* @private
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* @param {String} domain The domain name or email address.
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* @param {Function} callback The function that gets called for every
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* character.
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* @returns {Array} A new string of characters returned by the callback
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* function.
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*/
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function mapDomain(string, fn) {
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const parts = string.split('@');
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let result = '';
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if (parts.length > 1) {
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// In email addresses, only the domain name should be punycoded. Leave
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// the local part (i.e. everything up to `@`) intact.
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result = parts[0] + '@';
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string = parts[1];
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}
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// Avoid `split(regex)` for IE8 compatibility. See #17.
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string = string.replace(regexSeparators, '\x2E');
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const labels = string.split('.');
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const encoded = map(labels, fn).join('.');
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return result + encoded;
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}
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/**
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* Creates an array containing the numeric code points of each Unicode
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* character in the string. While JavaScript uses UCS-2 internally,
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* this function will convert a pair of surrogate halves (each of which
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* UCS-2 exposes as separate characters) into a single code point,
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* matching UTF-16.
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* @see `punycode.ucs2.encode`
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* @see <https://mathiasbynens.be/notes/javascript-encoding>
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* @memberOf punycode.ucs2
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* @name decode
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* @param {String} string The Unicode input string (UCS-2).
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* @returns {Array} The new array of code points.
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*/
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function ucs2decode(string) {
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const output = [];
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let counter = 0;
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const length = string.length;
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while (counter < length) {
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const value = string.charCodeAt(counter++);
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if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
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// It's a high surrogate, and there is a next character.
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const extra = string.charCodeAt(counter++);
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if ((extra & 0xFC00) == 0xDC00) { // Low surrogate.
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output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
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} else {
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// It's an unmatched surrogate; only append this code unit, in case the
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// next code unit is the high surrogate of a surrogate pair.
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output.push(value);
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counter--;
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}
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} else {
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output.push(value);
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}
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}
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return output;
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}
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/**
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* Creates a string based on an array of numeric code points.
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* @see `punycode.ucs2.decode`
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* @memberOf punycode.ucs2
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* @name encode
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* @param {Array} codePoints The array of numeric code points.
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* @returns {String} The new Unicode string (UCS-2).
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*/
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const ucs2encode = array => String.fromCodePoint(...array);
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/**
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* Converts a basic code point into a digit/integer.
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* @see `digitToBasic()`
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* @private
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* @param {Number} codePoint The basic numeric code point value.
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* @returns {Number} The numeric value of a basic code point (for use in
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* representing integers) in the range `0` to `base - 1`, or `base` if
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* the code point does not represent a value.
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*/
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const basicToDigit = function(codePoint) {
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if (codePoint - 0x30 < 0x0A) {
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return codePoint - 0x16;
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}
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if (codePoint - 0x41 < 0x1A) {
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return codePoint - 0x41;
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}
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if (codePoint - 0x61 < 0x1A) {
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return codePoint - 0x61;
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}
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return base;
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};
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/**
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* Converts a digit/integer into a basic code point.
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* @see `basicToDigit()`
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* @private
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* @param {Number} digit The numeric value of a basic code point.
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* @returns {Number} The basic code point whose value (when used for
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* representing integers) is `digit`, which needs to be in the range
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* `0` to `base - 1`. If `flag` is non-zero, the uppercase form is
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* used; else, the lowercase form is used. The behavior is undefined
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* if `flag` is non-zero and `digit` has no uppercase form.
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*/
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const digitToBasic = function(digit, flag) {
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// 0..25 map to ASCII a..z or A..Z
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// 26..35 map to ASCII 0..9
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return digit + 22 + 75 * (digit < 26) - ((flag != 0) << 5);
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};
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/**
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* Bias adaptation function as per section 3.4 of RFC 3492.
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* https://tools.ietf.org/html/rfc3492#section-3.4
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* @private
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*/
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const adapt = function(delta, numPoints, firstTime) {
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let k = 0;
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delta = firstTime ? floor(delta / damp) : delta >> 1;
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delta += floor(delta / numPoints);
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for (/* no initialization */; delta > baseMinusTMin * tMax >> 1; k += base) {
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delta = floor(delta / baseMinusTMin);
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}
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return floor(k + (baseMinusTMin + 1) * delta / (delta + skew));
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};
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/**
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* Converts a Punycode string of ASCII-only symbols to a string of Unicode
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* symbols.
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* @memberOf punycode
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* @param {String} input The Punycode string of ASCII-only symbols.
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* @returns {String} The resulting string of Unicode symbols.
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*/
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const decode = function(input) {
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// Don't use UCS-2.
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const output = [];
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const inputLength = input.length;
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let i = 0;
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let n = initialN;
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let bias = initialBias;
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// Handle the basic code points: let `basic` be the number of input code
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// points before the last delimiter, or `0` if there is none, then copy
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// the first basic code points to the output.
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let basic = input.lastIndexOf(delimiter);
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if (basic < 0) {
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basic = 0;
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}
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for (let j = 0; j < basic; ++j) {
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// if it's not a basic code point
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if (input.charCodeAt(j) >= 0x80) {
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error('not-basic');
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}
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output.push(input.charCodeAt(j));
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}
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// Main decoding loop: start just after the last delimiter if any basic code
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// points were copied; start at the beginning otherwise.
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for (let index = basic > 0 ? basic + 1 : 0; index < inputLength; /* no final expression */) {
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// `index` is the index of the next character to be consumed.
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// Decode a generalized variable-length integer into `delta`,
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// which gets added to `i`. The overflow checking is easier
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// if we increase `i` as we go, then subtract off its starting
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// value at the end to obtain `delta`.
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let oldi = i;
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for (let w = 1, k = base; /* no condition */; k += base) {
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if (index >= inputLength) {
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error('invalid-input');
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}
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const digit = basicToDigit(input.charCodeAt(index++));
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if (digit >= base || digit > floor((maxInt - i) / w)) {
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error('overflow');
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}
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i += digit * w;
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const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
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if (digit < t) {
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break;
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}
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const baseMinusT = base - t;
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if (w > floor(maxInt / baseMinusT)) {
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error('overflow');
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}
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w *= baseMinusT;
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}
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const out = output.length + 1;
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bias = adapt(i - oldi, out, oldi == 0);
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// `i` was supposed to wrap around from `out` to `0`,
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// incrementing `n` each time, so we'll fix that now:
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if (floor(i / out) > maxInt - n) {
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error('overflow');
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}
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n += floor(i / out);
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i %= out;
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// Insert `n` at position `i` of the output.
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output.splice(i++, 0, n);
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}
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return String.fromCodePoint(...output);
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};
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/**
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* Converts a string of Unicode symbols (e.g. a domain name label) to a
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* Punycode string of ASCII-only symbols.
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* @memberOf punycode
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* @param {String} input The string of Unicode symbols.
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* @returns {String} The resulting Punycode string of ASCII-only symbols.
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*/
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const encode = function(input) {
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const output = [];
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// Convert the input in UCS-2 to an array of Unicode code points.
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input = ucs2decode(input);
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// Cache the length.
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let inputLength = input.length;
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// Initialize the state.
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let n = initialN;
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let delta = 0;
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let bias = initialBias;
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// Handle the basic code points.
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for (const currentValue of input) {
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if (currentValue < 0x80) {
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output.push(stringFromCharCode(currentValue));
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}
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}
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let basicLength = output.length;
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let handledCPCount = basicLength;
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// `handledCPCount` is the number of code points that have been handled;
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// `basicLength` is the number of basic code points.
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// Finish the basic string with a delimiter unless it's empty.
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if (basicLength) {
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output.push(delimiter);
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}
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// Main encoding loop:
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while (handledCPCount < inputLength) {
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// All non-basic code points < n have been handled already. Find the next
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// larger one:
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let m = maxInt;
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for (const currentValue of input) {
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if (currentValue >= n && currentValue < m) {
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m = currentValue;
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}
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}
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// Increase `delta` enough to advance the decoder's <n,i> state to <m,0>,
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// but guard against overflow.
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const handledCPCountPlusOne = handledCPCount + 1;
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if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {
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error('overflow');
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}
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delta += (m - n) * handledCPCountPlusOne;
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n = m;
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for (const currentValue of input) {
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if (currentValue < n && ++delta > maxInt) {
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error('overflow');
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}
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if (currentValue == n) {
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// Represent delta as a generalized variable-length integer.
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let q = delta;
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for (let k = base; /* no condition */; k += base) {
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const t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
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if (q < t) {
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break;
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}
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const qMinusT = q - t;
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const baseMinusT = base - t;
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output.push(
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stringFromCharCode(digitToBasic(t + qMinusT % baseMinusT, 0))
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);
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q = floor(qMinusT / baseMinusT);
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}
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output.push(stringFromCharCode(digitToBasic(q, 0)));
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bias = adapt(delta, handledCPCountPlusOne, handledCPCount == basicLength);
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delta = 0;
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++handledCPCount;
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}
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}
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++delta;
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++n;
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}
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return output.join('');
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};
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/**
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* Converts a Punycode string representing a domain name or an email address
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* to Unicode. Only the Punycoded parts of the input will be converted, i.e.
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* it doesn't matter if you call it on a string that has already been
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* converted to Unicode.
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* @memberOf punycode
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* @param {String} input The Punycoded domain name or email address to
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* convert to Unicode.
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* @returns {String} The Unicode representation of the given Punycode
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* string.
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*/
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const toUnicode = function(input) {
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return mapDomain(input, function(string) {
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return regexPunycode.test(string)
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? decode(string.slice(4).toLowerCase())
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: string;
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});
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};
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/**
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* Converts a Unicode string representing a domain name or an email address to
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* Punycode. Only the non-ASCII parts of the domain name will be converted,
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* i.e. it doesn't matter if you call it with a domain that's already in
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* ASCII.
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* @memberOf punycode
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* @param {String} input The domain name or email address to convert, as a
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* Unicode string.
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* @returns {String} The Punycode representation of the given domain name or
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* email address.
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*/
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const toASCII = function(input) {
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return mapDomain(input, function(string) {
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return regexNonASCII.test(string)
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? 'xn--' + encode(string)
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: string;
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});
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};
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/*--------------------------------------------------------------------------*/
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/** Define the public API */
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const punycode = {
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/**
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* A string representing the current Punycode.js version number.
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* @memberOf punycode
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* @type String
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*/
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'version': '2.1.0',
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/**
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* An object of methods to convert from JavaScript's internal character
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* representation (UCS-2) to Unicode code points, and back.
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* @see <https://mathiasbynens.be/notes/javascript-encoding>
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* @memberOf punycode
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* @type Object
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*/
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'ucs2': {
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'decode': ucs2decode,
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'encode': ucs2encode
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},
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'decode': decode,
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'encode': encode,
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'toASCII': toASCII,
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'toUnicode': toUnicode
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};
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module.exports = punycode;
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