pluie-bin/lib/encoder.js

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JavaScript
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2016-12-18 23:39:08 +00:00
function TextEncoderLite() {
}
function TextDecoderLite() {
}
(function () {
'use strict';
// Taken from https://github.com/feross/buffer/blob/master/index.js
// Thanks Feross et al! :-)
function utf8ToBytes (string, units) {
units = units || Infinity
var codePoint
var length = string.length
var leadSurrogate = null
var bytes = []
var i = 0
for (; i < length; i++) {
codePoint = string.charCodeAt(i)
// is surrogate component
if (codePoint > 0xD7FF && codePoint < 0xE000) {
// last char was a lead
if (leadSurrogate) {
// 2 leads in a row
if (codePoint < 0xDC00) {
if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
leadSurrogate = codePoint
continue
} else {
// valid surrogate pair
codePoint = leadSurrogate - 0xD800 << 10 | codePoint - 0xDC00 | 0x10000
leadSurrogate = null
}
} else {
// no lead yet
if (codePoint > 0xDBFF) {
// unexpected trail
if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
continue
} else if (i + 1 === length) {
// unpaired lead
if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
continue
} else {
// valid lead
leadSurrogate = codePoint
continue
}
}
} else if (leadSurrogate) {
// valid bmp char, but last char was a lead
if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD)
leadSurrogate = null
}
// encode utf8
if (codePoint < 0x80) {
if ((units -= 1) < 0) break
bytes.push(codePoint)
} else if (codePoint < 0x800) {
if ((units -= 2) < 0) break
bytes.push(
codePoint >> 0x6 | 0xC0,
codePoint & 0x3F | 0x80
)
} else if (codePoint < 0x10000) {
if ((units -= 3) < 0) break
bytes.push(
codePoint >> 0xC | 0xE0,
codePoint >> 0x6 & 0x3F | 0x80,
codePoint & 0x3F | 0x80
)
} else if (codePoint < 0x200000) {
if ((units -= 4) < 0) break
bytes.push(
codePoint >> 0x12 | 0xF0,
codePoint >> 0xC & 0x3F | 0x80,
codePoint >> 0x6 & 0x3F | 0x80,
codePoint & 0x3F | 0x80
)
} else {
throw new Error('Invalid code point')
}
}
return bytes
}
function utf8Slice (buf, start, end) {
var res = ''
var tmp = ''
end = Math.min(buf.length, end || Infinity)
start = start || 0;
for (var i = start; i < end; i++) {
if (buf[i] <= 0x7F) {
res += decodeUtf8Char(tmp) + String.fromCharCode(buf[i])
tmp = ''
} else {
tmp += '%' + buf[i].toString(16)
}
}
return res + decodeUtf8Char(tmp)
}
function decodeUtf8Char (str) {
try {
return decodeURIComponent(str)
} catch (err) {
return String.fromCharCode(0xFFFD) // UTF 8 invalid char
}
}
TextEncoderLite.prototype.encode = function (str) {
var result;
if ('undefined' === typeof Uint8Array) {
result = utf8ToBytes(str);
} else {
result = new Uint8Array(utf8ToBytes(str));
}
return result;
};
TextDecoderLite.prototype.decode = function (bytes) {
return utf8Slice(bytes, 0, bytes.length);
}
}());
module.exports = function(ns) {
ns.TextEncoder = TextEncoderLite;
ns.TextDecoder = TextDecoderLite;
}