1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
'use strict';
var ucs2decode = require('./ucs2/decode')
, adapt = require('./lib/adapt')
, stringFromCharCode = String.fromCharCode
, floor = Math.floor
/** Highest positive signed 32-bit float value */
, maxInt = 2147483647 // aka. 0x7FFFFFFF or 2^31-1
, base = 36
, delimiter = '-' // '\x2D'
, initialBias = 72, initialN = 128, tMin = 1, tMax = 26;
/**
* 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.
*/
var 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);
};
/**
* 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.
*/
module.exports = function (input) {
var n,
delta,
handledCPCount,
basicLength,
bias,
j,
m,
q,
k,
t,
currentValue,
output = [],
/** `inputLength` will hold the number of code points in `input`. */
inputLength,
/** Cached calculation results */
handledCPCountPlusOne,
baseMinusT,
qMinusT;
// Convert the input in UCS-2 to Unicode
input = ucs2decode(input);
// Cache the length
inputLength = input.length;
// Initialize the state
n = initialN;
delta = 0;
bias = initialBias;
// Handle the basic code points
for (j = 0; j < inputLength; ++j) {
currentValue = input[j];
if (currentValue < 0x80) {
output.push(stringFromCharCode(currentValue));
}
}
handledCPCount = basicLength = output.length;
// `handledCPCount` is the number of code points that have been handled;
// `basicLength` is the number of basic code points.
// Finish the basic string - if it is not empty - with a delimiter
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:
for (m = maxInt, j = 0; j < inputLength; ++j) {
currentValue = input[j];
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
handledCPCountPlusOne = handledCPCount + 1;
if (m - n > floor((maxInt - delta) / handledCPCountPlusOne)) {
throw new RangeError('Overflow: input needs wider integers to process');
}
delta += (m - n) * handledCPCountPlusOne;
n = m;
for (j = 0; j < inputLength; ++j) {
currentValue = input[j];
if (currentValue < n && ++delta > maxInt) {
throw new RangeError('Overflow: input needs wider integers to process');
}
if (currentValue === n) {
// Represent delta as a generalized variable-length integer
for (q = delta, k = base; true; k += base) {
t = k <= bias ? tMin : (k >= bias + tMax ? tMax : k - bias);
if (q < t) {
break;
}
qMinusT = q - t;
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('');
};
|
