'use strict'
// Node has always utf-8
const utf8Decoder = new TextDecoder('utf-8')
const textDecoders = new Map([
['utf-8', utf8Decoder],
['utf8', utf8Decoder]
])
function getDecoder (charset) {
let lc
while (true) {
switch (charset) {
case 'utf-8':
case 'utf8':
return decoders.utf8
case 'latin1':
case 'ascii': // TODO: Make these a separate, strict decoder?
case 'us-ascii':
case 'iso-8859-1':
case 'iso8859-1':
case 'iso88591':
case 'iso_8859-1':
case 'windows-1252':
case 'iso_8859-1:1987':
case 'cp1252':
case 'x-cp1252':
return decoders.latin1
case 'utf16le':
case 'utf-16le':
case 'ucs2':
case 'ucs-2':
return decoders.utf16le
case 'base64':
return decoders.base64
default:
if (lc === undefined) {
lc = true
charset = charset.toLowerCase()
continue
}
return decoders.other.bind(charset)
}
}
}
const decoders = {
utf8: (data, sourceEncoding) => {
if (data.length === 0) {
return ''
}
if (typeof data === 'string') {
data = Buffer.from(data, sourceEncoding)
}
return data.utf8Slice(0, data.length)
},
latin1: (data, sourceEncoding) => {
if (data.length === 0) {
return ''
}
if (typeof data === 'string') {
return data
}
return data.latin1Slice(0, data.length)
},
utf16le: (data, sourceEncoding) => {
if (data.length === 0) {
return ''
}
if (typeof data === 'string') {
data = Buffer.from(data, sourceEncoding)
}
return data.ucs2Slice(0, data.length)
},
base64: (data, sourceEncoding) => {
if (data.length === 0) {
return ''
}
if (typeof data === 'string') {
data = Buffer.from(data, sourceEncoding)
}
return data.base64Slice(0, data.length)
},
other: (data, sourceEncoding) => {
if (data.length === 0) {
return ''
}
if (typeof data === 'string') {
data = Buffer.from(data, sourceEncoding)
}
if (textDecoders.has(this.toString())) {
try {
return textDecoders.get(this).decode(data)
} catch (e) { }
}
return typeof data === 'string'
? data
: data.toString()
}
}
function decodeText (text, sourceEncoding, destEncoding) {
if (text) {
return getDecoder(destEncoding)(text, sourceEncoding)
}
return text
}
module.exports = decodeText
