newrechaTVBOX/cat/tjs/lib/TextEncoder.js
2024-08-25 20:54:27 +08:00

107 lines
3.5 KiB
JavaScript

import Stream, { DEFAULT_ENCODING, getEncoding } from './text_decoder_index.js'
import { end_of_stream, finished, stringToCodePoints } from './text_decoder_utils.js'
import { encoders } from './table.js'
// 8.2 Interface TextEncoder
class TextEncoder {
/**
* @param {string=} label The label of the encoding. NONSTANDARD.
* @param {Object=} [options] NONSTANDARD.
*/
constructor(label, options = {}) {
// A TextEncoder object has an associated encoding and encoder.
/** @private */
this._encoding = null
/** @private @type {?Encoder} */
this._encoder = null
// Non-standard
/** @private @type {boolean} */
this._do_not_flush = false
/** @private @type {string} */
this._fatal = options['fatal'] ? 'fatal' : 'replacement'
// 2. Set enc's encoding to UTF-8's encoder.
if (options['NONSTANDARD_allowLegacyEncoding']) {
// NONSTANDARD behavior.
label = label !== undefined ? String(label) : DEFAULT_ENCODING
var encoding = getEncoding(label)
if (encoding === null || encoding.name === 'replacement')
throw RangeError('Unknown encoding: ' + label)
if (!encoders[encoding.name]) {
throw Error('Encoder not present.' +
' Did you forget to include encoding-indexes.js first?')
}
this._encoding = encoding
} else {
// Standard behavior.
this._encoding = getEncoding('utf-8')
if (label !== undefined && 'console' in global) {
console.warn('TextEncoder constructor called with encoding label, '
+ 'which is ignored.')
}
}
}
get encoding() {
return this._encoding.name.toLowerCase()
}
/**
* @param {string=} opt_string The string to encode.
* @param {Object=} options
*/
encode(opt_string = '', options = {}) {
// NOTE: This option is nonstandard. None of the encodings
// permitted for encoding (i.e. UTF-8, UTF-16) are stateful when
// the input is a USVString so streaming is not necessary.
if (!this._do_not_flush)
this._encoder = encoders[this._encoding.name]({
fatal: this._fatal === 'fatal' })
this._do_not_flush = Boolean(options['stream'])
// 1. Convert input to a stream.
const input = new Stream(stringToCodePoints(opt_string))
// 2. Let output be a new stream
const output = []
/** @type {?(number|!Array.<number>)} */
var result
// 3. While true, run these substeps:
while (true) {
// 1. Let token be the result of reading from input.
var token = input.read()
if (token === end_of_stream)
break
// 2. Let result be the result of processing token for encoder,
// input, output.
result = this._encoder.handler(input, token)
if (result === finished)
break
if (Array.isArray(result))
output.push.apply(output, /**@type {!Array.<number>}*/(result))
else
output.push(result)
}
// TODO: Align with spec algorithm.
if (!this._do_not_flush) {
while (true) {
result = this._encoder.handler(input, input.read())
if (result === finished)
break
if (Array.isArray(result))
output.push.apply(output, /**@type {!Array.<number>}*/(result))
else
output.push(result)
}
this._encoder = null
}
// 3. If result is finished, convert output into a byte sequence,
// and then return a Uint8Array object wrapping an ArrayBuffer
// containing output.
return new Uint8Array(output)
}
}
export {TextEncoder}