work.suroh.tk/node_modules/engine.io-parser/lib/utf8.js

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This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/*! https://mths.be/utf8js v2.1.2 by @mathias */
var stringFromCharCode = String.fromCharCode;
// Taken from https://mths.be/punycode
function ucs2decode(string) {
var output = [];
var counter = 0;
var length = string.length;
var value;
var extra;
while (counter < length) {
value = string.charCodeAt(counter++);
if (value >= 0xD800 && value <= 0xDBFF && counter < length) {
// high surrogate, and there is a next character
extra = string.charCodeAt(counter++);
if ((extra & 0xFC00) == 0xDC00) { // low surrogate
output.push(((value & 0x3FF) << 10) + (extra & 0x3FF) + 0x10000);
} else {
// unmatched surrogate; only append this code unit, in case the next
// code unit is the high surrogate of a surrogate pair
output.push(value);
counter--;
}
} else {
output.push(value);
}
}
return output;
}
// Taken from https://mths.be/punycode
function ucs2encode(array) {
var length = array.length;
var index = -1;
var value;
var output = '';
while (++index < length) {
value = array[index];
if (value > 0xFFFF) {
value -= 0x10000;
output += stringFromCharCode(value >>> 10 & 0x3FF | 0xD800);
value = 0xDC00 | value & 0x3FF;
}
output += stringFromCharCode(value);
}
return output;
}
function checkScalarValue(codePoint, strict) {
if (codePoint >= 0xD800 && codePoint <= 0xDFFF) {
if (strict) {
throw Error(
'Lone surrogate U+' + codePoint.toString(16).toUpperCase() +
' is not a scalar value'
);
}
return false;
}
return true;
}
/*--------------------------------------------------------------------------*/
function createByte(codePoint, shift) {
return stringFromCharCode(((codePoint >> shift) & 0x3F) | 0x80);
}
function encodeCodePoint(codePoint, strict) {
if ((codePoint & 0xFFFFFF80) == 0) { // 1-byte sequence
return stringFromCharCode(codePoint);
}
var symbol = '';
if ((codePoint & 0xFFFFF800) == 0) { // 2-byte sequence
symbol = stringFromCharCode(((codePoint >> 6) & 0x1F) | 0xC0);
}
else if ((codePoint & 0xFFFF0000) == 0) { // 3-byte sequence
if (!checkScalarValue(codePoint, strict)) {
codePoint = 0xFFFD;
}
symbol = stringFromCharCode(((codePoint >> 12) & 0x0F) | 0xE0);
symbol += createByte(codePoint, 6);
}
else if ((codePoint & 0xFFE00000) == 0) { // 4-byte sequence
symbol = stringFromCharCode(((codePoint >> 18) & 0x07) | 0xF0);
symbol += createByte(codePoint, 12);
symbol += createByte(codePoint, 6);
}
symbol += stringFromCharCode((codePoint & 0x3F) | 0x80);
return symbol;
}
function utf8encode(string, opts) {
opts = opts || {};
var strict = false !== opts.strict;
var codePoints = ucs2decode(string);
var length = codePoints.length;
var index = -1;
var codePoint;
var byteString = '';
while (++index < length) {
codePoint = codePoints[index];
byteString += encodeCodePoint(codePoint, strict);
}
return byteString;
}
/*--------------------------------------------------------------------------*/
function readContinuationByte() {
if (byteIndex >= byteCount) {
throw Error('Invalid byte index');
}
var continuationByte = byteArray[byteIndex] & 0xFF;
byteIndex++;
if ((continuationByte & 0xC0) == 0x80) {
return continuationByte & 0x3F;
}
// If we end up here, its not a continuation byte
throw Error('Invalid continuation byte');
}
function decodeSymbol(strict) {
var byte1;
var byte2;
var byte3;
var byte4;
var codePoint;
if (byteIndex > byteCount) {
throw Error('Invalid byte index');
}
if (byteIndex == byteCount) {
return false;
}
// Read first byte
byte1 = byteArray[byteIndex] & 0xFF;
byteIndex++;
// 1-byte sequence (no continuation bytes)
if ((byte1 & 0x80) == 0) {
return byte1;
}
// 2-byte sequence
if ((byte1 & 0xE0) == 0xC0) {
byte2 = readContinuationByte();
codePoint = ((byte1 & 0x1F) << 6) | byte2;
if (codePoint >= 0x80) {
return codePoint;
} else {
throw Error('Invalid continuation byte');
}
}
// 3-byte sequence (may include unpaired surrogates)
if ((byte1 & 0xF0) == 0xE0) {
byte2 = readContinuationByte();
byte3 = readContinuationByte();
codePoint = ((byte1 & 0x0F) << 12) | (byte2 << 6) | byte3;
if (codePoint >= 0x0800) {
return checkScalarValue(codePoint, strict) ? codePoint : 0xFFFD;
} else {
throw Error('Invalid continuation byte');
}
}
// 4-byte sequence
if ((byte1 & 0xF8) == 0xF0) {
byte2 = readContinuationByte();
byte3 = readContinuationByte();
byte4 = readContinuationByte();
codePoint = ((byte1 & 0x07) << 0x12) | (byte2 << 0x0C) |
(byte3 << 0x06) | byte4;
if (codePoint >= 0x010000 && codePoint <= 0x10FFFF) {
return codePoint;
}
}
throw Error('Invalid UTF-8 detected');
}
var byteArray;
var byteCount;
var byteIndex;
function utf8decode(byteString, opts) {
opts = opts || {};
var strict = false !== opts.strict;
byteArray = ucs2decode(byteString);
byteCount = byteArray.length;
byteIndex = 0;
var codePoints = [];
var tmp;
while ((tmp = decodeSymbol(strict)) !== false) {
codePoints.push(tmp);
}
return ucs2encode(codePoints);
}
module.exports = {
version: '2.1.2',
encode: utf8encode,
decode: utf8decode
};