Преобразование punycode с тире в Unicode

Я потратил время на создание кода ниже. Он основан на коде C в RFC 3492. Чтобы использовать его с доменными именами, вы должны удалить / добавить xn-- из / в ввод / вывод для / из декодирования / кодирования.

utf16-class необходим для преобразования внутреннего символьного представления JavaScripts в Unicode и обратно.

Существуют также функции ToASCII и ToUnicode, упрощающие преобразование между IDN и ASCII с мелким кодом.

//Javascript Punycode converter derived from example in RFC3492.
//This implementation is created by [email protected] and released into public domain
var punycode = new function Punycode() {
    // This object converts to and from puny-code used in IDN
    //
    // punycode.ToASCII ( domain )
    // 
    // Returns a puny coded representation of "domain".
    // It only converts the part of the domain name that
    // has non ASCII characters. I.e. it dosent matter if
    // you call it with a domain that already is in ASCII.
    //
    // punycode.ToUnicode (domain)
    //
    // Converts a puny-coded domain name to unicode.
    // It only converts the puny-coded parts of the domain name.
    // I.e. it dosent matter if you call it on a string
    // that already has been converted to unicode.
    //
    //
    this.utf16 = {
        // The utf16-class is necessary to convert from javascripts internal character representation to unicode and back.
        decode:function(input){
            var output = [], i=0, len=input.length,value,extra;
            while (i < len) {
                value = input.charCodeAt(i++);
                if ((value & 0xF800) === 0xD800) {
                    extra = input.charCodeAt(i++);
                    if ( ((value & 0xFC00) !== 0xD800) || ((extra & 0xFC00) !== 0xDC00) ) {
                        throw new RangeError("UTF-16(decode): Illegal UTF-16 sequence");
                    }
                    value = ((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000;
                }
                output.push(value);
            }
            return output;
        },
        encode:function(input){
            var output = [], i=0, len=input.length,value;
            while (i < len) {
                value = input[i++];
                if ( (value & 0xF800) === 0xD800 ) {
                    throw new RangeError("UTF-16(encode): Illegal UTF-16 value");
                }
                if (value > 0xFFFF) {
                    value -= 0x10000;
                    output.push(String.fromCharCode(((value >>>10) & 0x3FF) | 0xD800));
                    value = 0xDC00 | (value & 0x3FF);
                }
                output.push(String.fromCharCode(value));
            }
            return output.join("");
        }
    }

    //Default parameters
    var initial_n = 0x80;
    var initial_bias = 72;
    var delimiter = "\x2D";
    var base = 36;
    var damp = 700;
    var tmin=1;
    var tmax=26;
    var skew=38;
    var maxint = 0x7FFFFFFF;

    // decode_digit(cp) returns the numeric value of a basic code 
    // point (for use in representing integers) in the range 0 to
    // base-1, or base if cp is does not represent a value.

    function decode_digit(cp) {
        return cp - 48 < 10 ? cp - 22 : cp - 65 < 26 ? cp - 65 : cp - 97 < 26 ? cp - 97 : base;
    }

    // encode_digit(d,flag) returns the basic code point whose value
    // (when used for representing integers) is d, which needs to be in
    // the range 0 to base-1. The lowercase form is used unless flag is
    // nonzero, in which case the uppercase form is used. The behavior
    // is undefined if flag is nonzero and digit d has no uppercase form. 

    function encode_digit(d, flag) {
        return d + 22 + 75 * (d < 26) - ((flag != 0) << 5);
        //  0..25 map to ASCII a..z or A..Z 
        // 26..35 map to ASCII 0..9
    }
    //** Bias adaptation function **
    function adapt(delta, numpoints, firsttime ) {
        var k;
        delta = firsttime ? Math.floor(delta / damp) : (delta >> 1);
        delta += Math.floor(delta / numpoints);

        for (k = 0; delta > (((base - tmin) * tmax) >> 1); k += base) {
                delta = Math.floor(delta / ( base - tmin ));
        }
        return Math.floor(k + (base - tmin + 1) * delta / (delta + skew));
    }

    // encode_basic(bcp,flag) forces a basic code point to lowercase if flag is zero,
    // uppercase if flag is nonzero, and returns the resulting code point.
    // The code point is unchanged if it is caseless.
    // The behavior is undefined if bcp is not a basic code point.

    function encode_basic(bcp, flag) {
        bcp -= (bcp - 97 < 26) << 5;
        return bcp + ((!flag && (bcp - 65 < 26)) << 5);
    }

    // Main decode
    this.decode=function(input,preserveCase) {
        // Dont use utf16
        var output=[];
        var case_flags=[];
        var input_length = input.length;

        var n, out, i, bias, basic, j, ic, oldi, w, k, digit, t, len;

        // Initialize the state: 

        n = initial_n;
        i = 0;
        bias = initial_bias;

        // 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.

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

        for (j = 0; j < basic; ++j) {
            if (preserveCase) case_flags[output.length] = ( input.charCodeAt(j) -65 < 26);
            if ( input.charCodeAt(j) >= 0x80) {
                throw new RangeError("Illegal input >= 0x80");
            }
            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 (ic = basic > 0 ? basic + 1 : 0; ic < input_length; ) {

            // ic 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.
            for (oldi = i, w = 1, k = base; ; k += base) {
                    if (ic >= input_length) {
                        throw RangeError ("punycode_bad_input(1)");
                    }
                    digit = decode_digit(input.charCodeAt(ic++));

                    if (digit >= base) {
                        throw RangeError("punycode_bad_input(2)");
                    }
                    if (digit > Math.floor((maxint - i) / w)) {
                        throw RangeError ("punycode_overflow(1)");
                    }
                    i += digit * w;
                    t = k <= bias ? tmin : k >= bias + tmax ? tmax : k - bias;
                    if (digit < t) { break; }
                    if (w > Math.floor(maxint / (base - t))) {
                        throw RangeError("punycode_overflow(2)");
                    }
                    w *= (base - t);
            }

            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 ( Math.floor(i / out) > maxint - n) {
                throw RangeError("punycode_overflow(3)");
            }
            n += Math.floor( i / out ) ;
            i %= out;

            // Insert n at position i of the output: 
            // Case of last character determines uppercase flag: 
            if (preserveCase) { case_flags.splice(i, 0, input.charCodeAt(ic -1) -65 < 26);}

            output.splice(i, 0, n);
            i++;
        }
        if (preserveCase) {
            for (i = 0, len = output.length; i < len; i++) {
                if (case_flags[i]) {
                    output[i] = (String.fromCharCode(output[i]).toUpperCase()).charCodeAt(0);
                }
            }
        }
        return this.utf16.encode(output);
    };

    //** Main encode function **

    this.encode = function (input,preserveCase) {
        //** Bias adaptation function **

        var n, delta, h, b, bias, j, m, q, k, t, ijv, case_flags;

        if (preserveCase) {
            // Preserve case, step1 of 2: Get a list of the unaltered string
            case_flags = this.utf16.decode(input);
        }
        // Converts the input in UTF-16 to Unicode
        input = this.utf16.decode(input.toLowerCase());

        var input_length = input.length; // Cache the length

        if (preserveCase) {
            // Preserve case, step2 of 2: Modify the list to true/false
            for (j=0; j < input_length; j++) {
                case_flags[j] = input[j] != case_flags[j];
            }
        }

        var output=[];


        // Initialize the state: 
        n = initial_n;
        delta = 0;
        bias = initial_bias;

        // Handle the basic code points: 
        for (j = 0; j < input_length; ++j) {
            if ( input[j] < 0x80) {
                output.push(
                    String.fromCharCode(
                        case_flags ? encode_basic(input[j], case_flags[j]) : input[j]
                    )
                );
            }
        }

        h = b = output.length;

        // h is the number of code points that have been handled, b is the
        // number of basic code points 

        if (b > 0) output.push(delimiter);

        // Main encoding loop: 
        //
        while (h < input_length) {
            // All non-basic code points < n have been
            // handled already. Find the next larger one: 

            for (m = maxint, j = 0; j < input_length; ++j) {
                ijv = input[j];
                if (ijv >= n && ijv < m) m = ijv;
            }

            // Increase delta enough to advance the decoder's
            // <n,i> state to <m,0>, but guard against overflow: 

            if (m - n > Math.floor((maxint - delta) / (h + 1))) {
                throw RangeError("punycode_overflow (1)");
            }
            delta += (m - n) * (h + 1);
            n = m;

            for (j = 0; j < input_length; ++j) {
                ijv = input[j];

                if (ijv < n ) {
                    if (++delta > maxint) return Error("punycode_overflow(2)");
                }

                if (ijv == n) {
                    // Represent delta as a generalized variable-length integer: 
                    for (q = delta, k = base; ; k += base) {
                        t = k <= bias ? tmin : k >= bias + tmax ? tmax : k - bias;
                        if (q < t) break;
                        output.push( String.fromCharCode(encode_digit(t + (q - t) % (base - t), 0)) );
                        q = Math.floor( (q - t) / (base - t) );
                    }
                    output.push( String.fromCharCode(encode_digit(q, preserveCase && case_flags[j] ? 1:0 )));
                    bias = adapt(delta, h + 1, h == b);
                    delta = 0;
                    ++h;
                }
            }

            ++delta, ++n;
        }
        return output.join("");
    }

    this.ToASCII = function ( domain ) {
        var domain_array = domain.split(".");
        var out = [];
        for (var i=0; i < domain_array.length; ++i) {
            var s = domain_array[i];
            out.push(
                s.match(/[^A-Za-z0-9-]/) ?
                "xn--" + punycode.encode(s) :
                s
            );
        }
        return out.join(".");
    }
    this.ToUnicode = function ( domain ) {
        var domain_array = domain.split(".");
        var out = [];
        for (var i=0; i < domain_array.length; ++i) {
            var s = domain_array[i];
            out.push(
                s.match(/^xn--/) ?
                punycode.decode(s.slice(4)) :
                s
            );
        }
        return out.join(".");
    }
}();

Лицензия на обновление:
Из RFC3492:

Disclaimer and license

Regarding this entire document or any portion of it (including the pseudocode and C code), the author makes no guarantees and is not responsible for any damage resulting from its use. The author grants irrevocable permission to anyone to use, modify, and distribute it in any way that does not diminish the rights of anyone else to use, modify, and distribute it, provided that redistributed derivative works do not contain misleading author or version information. Derivative works need not be licensed under similar terms.

Я поместил свою работу в этот punycode и utf16 в общественное достояние. Было бы неплохо получить письмо по электронной почте о том, в каком проекте вы его используете.