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182 lines
5.5 KiB
182 lines
5.5 KiB
'use strict'; |
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// based on https://github.com/bestiejs/punycode.js/blob/master/punycode.js |
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var global = require('../internals/global'); |
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var uncurryThis = require('../internals/function-uncurry-this'); |
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var maxInt = 2147483647; // aka. 0x7FFFFFFF or 2^31-1 |
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var base = 36; |
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var tMin = 1; |
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var tMax = 26; |
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var skew = 38; |
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var damp = 700; |
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var initialBias = 72; |
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var initialN = 128; // 0x80 |
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var delimiter = '-'; // '\x2D' |
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var regexNonASCII = /[^\0-\u007E]/; // non-ASCII chars |
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var regexSeparators = /[.\u3002\uFF0E\uFF61]/g; // RFC 3490 separators |
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var OVERFLOW_ERROR = 'Overflow: input needs wider integers to process'; |
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var baseMinusTMin = base - tMin; |
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var RangeError = global.RangeError; |
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var exec = uncurryThis(regexSeparators.exec); |
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var floor = Math.floor; |
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var fromCharCode = String.fromCharCode; |
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var charCodeAt = uncurryThis(''.charCodeAt); |
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var join = uncurryThis([].join); |
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var push = uncurryThis([].push); |
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var replace = uncurryThis(''.replace); |
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var split = uncurryThis(''.split); |
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var toLowerCase = uncurryThis(''.toLowerCase); |
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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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*/ |
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var ucs2decode = function (string) { |
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var output = []; |
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var counter = 0; |
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var length = string.length; |
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while (counter < length) { |
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var value = charCodeAt(string, 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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var extra = charCodeAt(string, counter++); |
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if ((extra & 0xFC00) == 0xDC00) { // Low surrogate. |
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push(output, ((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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push(output, value); |
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counter--; |
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} |
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} else { |
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push(output, 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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* Converts a digit/integer into a basic code point. |
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*/ |
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var digitToBasic = function (digit) { |
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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); |
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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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*/ |
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var adapt = function (delta, numPoints, firstTime) { |
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var 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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while (delta > baseMinusTMin * tMax >> 1) { |
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delta = floor(delta / baseMinusTMin); |
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k += base; |
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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 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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*/ |
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var encode = function (input) { |
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var 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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var inputLength = input.length; |
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// Initialize the state. |
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var n = initialN; |
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var delta = 0; |
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var bias = initialBias; |
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var i, currentValue; |
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// Handle the basic code points. |
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for (i = 0; i < input.length; i++) { |
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currentValue = input[i]; |
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if (currentValue < 0x80) { |
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push(output, fromCharCode(currentValue)); |
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} |
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} |
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var basicLength = output.length; // number of basic code points. |
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var handledCPCount = basicLength; // number of code points that have been handled; |
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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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push(output, 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 larger one: |
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var m = maxInt; |
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for (i = 0; i < input.length; i++) { |
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currentValue = input[i]; |
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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>, but guard against overflow. |
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var handledCPCountPlusOne = handledCPCount + 1; |
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if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) { |
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throw RangeError(OVERFLOW_ERROR); |
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} |
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delta += (m - n) * handledCPCountPlusOne; |
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n = m; |
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for (i = 0; i < input.length; i++) { |
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currentValue = input[i]; |
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if (currentValue < n && ++delta > maxInt) { |
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throw RangeError(OVERFLOW_ERROR); |
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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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var q = delta; |
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var k = base; |
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while (true) { |
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var t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias); |
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if (q < t) break; |
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var qMinusT = q - t; |
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var baseMinusT = base - t; |
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push(output, fromCharCode(digitToBasic(t + qMinusT % baseMinusT))); |
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q = floor(qMinusT / baseMinusT); |
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k += base; |
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} |
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push(output, fromCharCode(digitToBasic(q))); |
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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 join(output, ''); |
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}; |
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module.exports = function (input) { |
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var encoded = []; |
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var labels = split(replace(toLowerCase(input), regexSeparators, '\u002E'), '.'); |
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var i, label; |
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for (i = 0; i < labels.length; i++) { |
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label = labels[i]; |
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push(encoded, exec(regexNonASCII, label) ? 'xn--' + encode(label) : label); |
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} |
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return join(encoded, '.'); |
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};
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