punycode

Punycode编码/解码的实现。

用法

const punycode = require('punycode');
console.log(punycode.encode('用法')); //nwwn1p
console.log(punycode.decode('nwwn1p')) //用法

console.log(punycode.toIDN('用法.中国')); //xn--nwwn1p.xn--fiqs8s
console.log(punycode.fromIDN('xn--nwwn1p.xn--fiqs8s')) //用法.中国

源代码

module.exports = (function() {
    var B = 1;
    var w = 26;
    var A = 36;
    var s = 128;
    var C = 72;
    var z = 700;
    var r = 38;
    var t = "-";
    var u = 2147483647;
    var v = {};
    var o = function(d, c) {
        return Math.floor(d / c)
    };
    var x = function(a, c, b) {
        a = o(a, b ? z : 2);
        a = a + o(a, c);
        var d = 0;
        while (a > o((A - B) * w, 2)) {
            a = o(a, A - B);
            d = d + A
        }
        return d + o((A - B + 1) * a, a + r)
    };
    var p = function(a) {
        return a < 128
    };
    var q = function(a) {
        if (a < 26) {
            return a + "a".charCodeAt(0)
        } else {
            if (a < 36) {
                return a - 26 + "0".charCodeAt(0)
            } else {
                return 0
            }
        }
    };
    var y = function(a) {
        if (a - "0".charCodeAt(0) < 10) {
            return a - "0".charCodeAt(0) + 26
        } else {
            if (a - "a".charCodeAt(0) < 26) {
                return a - "a".charCodeAt(0)
            } else {
                return 0
            }
        }
    };
    v.toIDN = function(c) {
        var b = c.split(".");
        var a = 0;
        var d = "";
        for (a = 0; a < b.length; a++) {
            if (/^[0-9a-zA-Z\\-]+$/igm.test(b[a])) {
                d += b[a] + "."
            } else {
                d += "xn--" + v.encode(b[a]) + "."
            }
        }
        if (d != "") {
            d = d.substr(0, d.length - 1)
        }
        return d
    };
    v.fromIDN = function(d) {
        var c = d.split(".");
        var a = 0;
        var e = "";
        for (a = 0; a < c.length; a++) {
            var b = c[a];
            if (b.toLowerCase().indexOf("xn--") == 0) {
                e += v.decode(b.substr(4)) + "."
            } else {
                e += b + "."
            }
        }
        if (e != "") {
            e = e.substr(0, e.length - 1)
        }
        return e
    };
    v.encode = function(d) {
        var e = s;
        var c = 0;
        var i = C;
        var b = "";
        var g = 0;
        d = d.split("");
        for (var k = 0; k < d.length; k++) {
            var h = d[k].charCodeAt(0);
            if (p(h)) {
                b += d[k];
                g++
            }
        }
        if (g > 0) {
            b += t
        }
        var j = g;
        while (j < d.length) {
            var n = u;
            for (var k = 0; k < d.length; k++) {
                var h = d[k].charCodeAt(0);
                if (h >= e && h < n) {
                    n = h
                }
            }
            if (n - e > o(u - c, j + 1)) {
                return ""
            }
            c = c + (n - e) * (j + 1);
            e = n;
            for (var l = 0; l < d.length; l++) {
                var h = d[l].charCodeAt(0);
                if (h < e) {
                    c++;
                    if (0 == c) {
                        return ""
                    }
                }
                if (h == e) {
                    var f = c;
                    for (var m = A;; m += A) {
                        var a;
                        if (m <= i) {
                            a = B
                        } else {
                            if (m >= i + w) {
                                a = w
                            } else {
                                a = m - i
                            }
                        } if (f < a) {
                            break
                        }
                        b += String.fromCharCode(q(a + (f - a) % (A - a)));
                        f = o(f - a, A - a)
                    }
                    b += String.fromCharCode(q(f));
                    i = x(c, j + 1, j == g);
                    c = 0;
                    j++
                }
            }
            c++;
            e++
        }
        return b
    };
    v.decode = function(e) {
        var f = s;
        var l = 0;
        var k = C;
        var d = "";
        var j = e.lastIndexOf(t);
        e = e.split("");
        if (j > 0) {
            for (var m = 0; m < j; m++) {
                var i = e[m].charCodeAt(0);
                if (!p(i)) {
                    return ""
                }
                d += e[m]
            }
            j++
        } else {
            j = 0
        }
        while (j < e.length) {
            var h = l;
            var c = 1;
            for (var b = A;; b += A) {
                if (j == e.length) {
                    return ""
                }
                var i = e[j++].charCodeAt(0);
                var g = y(i);
                if (g > o(u - l, c)) {
                    return ""
                }
                l = l + g * c;
                var a;
                if (b <= k) {
                    a = B
                } else {
                    if (b >= k + w) {
                        a = w
                    } else {
                        a = b - k
                    }
                } if (g < a) {
                    break
                }
                c = c * (A - a)
            }
            k = x(l - h, d.length + 1, h == 0);
            if (o(l, d.length + 1) > u - f) {
                return ""
            }
            f = f + o(l, d.length + 1);
            l = l % (d.length + 1);
            var n = String.fromCharCode(f);
            if (l == 0) {
                d = n + d
            } else {
                d = d.substr(0, l) + n + d.substr(l)
            }
            l++
        }
        return d
    };
    return v
})();