252 lines
8.3 KiB
JavaScript
252 lines
8.3 KiB
JavaScript
import { inRange, decoderError, encoderError, isASCIICodePoint,
|
||
end_of_stream, finished, isASCIIByte, floor } from './text_decoder_utils.js'
|
||
import index, {
|
||
indexGB18030RangesCodePointFor, indexGB18030RangesPointerFor,
|
||
indexCodePointFor, indexPointerFor } from './text_decoder_indexes.js'
|
||
|
||
// 11.2 gb18030
|
||
|
||
// 11.2.1 gb18030 decoder
|
||
/**
|
||
* @constructor
|
||
* @implements {Decoder}
|
||
* @param {{fatal: boolean}} options
|
||
*/
|
||
export class GB18030Decoder {
|
||
constructor(options) {
|
||
const { fatal } = options
|
||
this.fatal = fatal
|
||
// gb18030's decoder has an associated gb18030 first, gb18030
|
||
// second, and gb18030 third (all initially 0x00).
|
||
this.gb18030_first = 0x00
|
||
this.gb18030_second = 0x00,
|
||
this.gb18030_third = 0x00
|
||
}
|
||
/**
|
||
* @param {Stream} stream The stream of bytes being decoded.
|
||
* @param {number} bite The next byte read from the stream.
|
||
* @return The next code point(s) decoded, or null if not enough data exists in the input stream to decode a complete code point.
|
||
*/
|
||
handler(stream, bite) {
|
||
// 1. If byte is end-of-stream and gb18030 first, gb18030
|
||
// second, and gb18030 third are 0x00, return finished.
|
||
if (bite === end_of_stream && this.gb18030_first === 0x00 &&
|
||
this.gb18030_second === 0x00 && this.gb18030_third === 0x00) {
|
||
return finished
|
||
}
|
||
// 2. If byte is end-of-stream, and gb18030 first, gb18030
|
||
// second, or gb18030 third is not 0x00, set gb18030 first,
|
||
// gb18030 second, and gb18030 third to 0x00, and return error.
|
||
if (bite === end_of_stream &&
|
||
(this.gb18030_first !== 0x00 || this.gb18030_second !== 0x00 ||
|
||
this.gb18030_third !== 0x00)) {
|
||
this.gb18030_first = 0x00
|
||
this.gb18030_second = 0x00
|
||
this.gb18030_third = 0x00
|
||
decoderError(this.fatal)
|
||
}
|
||
var code_point
|
||
// 3. If gb18030 third is not 0x00, run these substeps:
|
||
if (this.gb18030_third !== 0x00) {
|
||
// 1. Let code point be null.
|
||
code_point = null
|
||
// 2. If byte is in the range 0x30 to 0x39, inclusive, set
|
||
// code point to the index gb18030 ranges code point for
|
||
// (((gb18030 first − 0x81) × 10 + gb18030 second − 0x30) ×
|
||
// 126 + gb18030 third − 0x81) × 10 + byte − 0x30.
|
||
if (inRange(bite, 0x30, 0x39)) {
|
||
code_point = indexGB18030RangesCodePointFor(
|
||
(((this.gb18030_first - 0x81) * 10 + this.gb18030_second - 0x30) * 126 +
|
||
this.gb18030_third - 0x81) * 10 + bite - 0x30)
|
||
}
|
||
|
||
// 3. Let buffer be a byte sequence consisting of gb18030
|
||
// second, gb18030 third, and byte, in order.
|
||
var buffer = [this.gb18030_second, this.gb18030_third, bite]
|
||
|
||
// 4. Set gb18030 first, gb18030 second, and gb18030 third to
|
||
// 0x00.
|
||
this.gb18030_first = 0x00
|
||
this.gb18030_second = 0x00
|
||
this.gb18030_third = 0x00
|
||
|
||
// 5. If code point is null, prepend buffer to stream and
|
||
// return error.
|
||
if (code_point === null) {
|
||
stream.prepend(buffer)
|
||
return decoderError(this.fatal)
|
||
}
|
||
|
||
// 6. Return a code point whose value is code point.
|
||
return code_point
|
||
}
|
||
|
||
// 4. If gb18030 second is not 0x00, run these substeps:
|
||
if (this.gb18030_second !== 0x00) {
|
||
// 1. If byte is in the range 0x81 to 0xFE, inclusive, set
|
||
// gb18030 third to byte and return continue.
|
||
if (inRange(bite, 0x81, 0xFE)) {
|
||
this.gb18030_third = bite
|
||
return null
|
||
}
|
||
|
||
// 2. Prepend gb18030 second followed by byte to stream, set
|
||
// gb18030 first and gb18030 second to 0x00, and return error.
|
||
stream.prepend([this.gb18030_second, bite])
|
||
this.gb18030_first = 0x00
|
||
this.gb18030_second = 0x00
|
||
return decoderError(this.fatal)
|
||
}
|
||
|
||
// 5. If gb18030 first is not 0x00, run these substeps:
|
||
if (this.gb18030_first !== 0x00) {
|
||
// 1. If byte is in the range 0x30 to 0x39, inclusive, set
|
||
// gb18030 second to byte and return continue.
|
||
if (inRange(bite, 0x30, 0x39)) {
|
||
this.gb18030_second = bite
|
||
return null
|
||
}
|
||
|
||
// 2. Let lead be gb18030 first, let pointer be null, and set
|
||
// gb18030 first to 0x00.
|
||
var lead = this.gb18030_first
|
||
var pointer = null
|
||
this.gb18030_first = 0x00
|
||
|
||
// 3. Let offset be 0x40 if byte is less than 0x7F and 0x41
|
||
// otherwise.
|
||
var offset = bite < 0x7F ? 0x40 : 0x41
|
||
|
||
// 4. If byte is in the range 0x40 to 0x7E, inclusive, or 0x80
|
||
// to 0xFE, inclusive, set pointer to (lead − 0x81) × 190 +
|
||
// (byte − offset).
|
||
if (inRange(bite, 0x40, 0x7E) || inRange(bite, 0x80, 0xFE))
|
||
pointer = (lead - 0x81) * 190 + (bite - offset)
|
||
|
||
// 5. Let code point be null if pointer is null and the index
|
||
// code point for pointer in index gb18030 otherwise.
|
||
code_point = pointer === null ? null :
|
||
indexCodePointFor(pointer, index('gb18030'))
|
||
|
||
// 6. If code point is null and byte is an ASCII byte, prepend
|
||
// byte to stream.
|
||
if (code_point === null && isASCIIByte(bite))
|
||
stream.prepend(bite)
|
||
|
||
// 7. If code point is null, return error.
|
||
if (code_point === null)
|
||
return decoderError(this.fatal)
|
||
|
||
// 8. Return a code point whose value is code point.
|
||
return code_point
|
||
}
|
||
|
||
// 6. If byte is an ASCII byte, return a code point whose value
|
||
// is byte.
|
||
if (isASCIIByte(bite))
|
||
return bite
|
||
|
||
// 7. If byte is 0x80, return code point U+20AC.
|
||
if (bite === 0x80)
|
||
return 0x20AC
|
||
|
||
// 8. If byte is in the range 0x81 to 0xFE, inclusive, set
|
||
// gb18030 first to byte and return continue.
|
||
if (inRange(bite, 0x81, 0xFE)) {
|
||
this.gb18030_first = bite
|
||
return null
|
||
}
|
||
|
||
// 9. Return error.
|
||
return decoderError(this.fatal)
|
||
}
|
||
}
|
||
|
||
// 11.2.2 gb18030 encoder
|
||
/**
|
||
* @implements {Encoder}
|
||
*/
|
||
export class GB18030Encoder {
|
||
/**
|
||
* @param {Stream} stream Input stream.
|
||
* @param {number} code_point Next code point read from the stream.
|
||
* @return Byte(s) to emit.
|
||
*/
|
||
handler(stream, code_point) {
|
||
// 1. If code point is end-of-stream, return finished.
|
||
if (code_point === end_of_stream)
|
||
return finished
|
||
|
||
// 2. If code point is an ASCII code point, return a byte whose
|
||
// value is code point.
|
||
if (isASCIICodePoint(code_point))
|
||
return code_point
|
||
|
||
// 3. If code point is U+E5E5, return error with code point.
|
||
if (code_point === 0xE5E5)
|
||
return encoderError(code_point)
|
||
|
||
// 4. If the gbk flag is set and code point is U+20AC, return
|
||
// byte 0x80.
|
||
if (this.gbk_flag && code_point === 0x20AC)
|
||
return 0x80
|
||
|
||
// 5. Let pointer be the index pointer for code point in index
|
||
// gb18030.
|
||
var pointer = indexPointerFor(code_point, index('gb18030'))
|
||
|
||
// 6. If pointer is not null, run these substeps:
|
||
if (pointer !== null) {
|
||
// 1. Let lead be floor(pointer / 190) + 0x81.
|
||
var lead = floor(pointer / 190) + 0x81
|
||
|
||
// 2. Let trail be pointer % 190.
|
||
var trail = pointer % 190
|
||
|
||
// 3. Let offset be 0x40 if trail is less than 0x3F and 0x41 otherwise.
|
||
var offset = trail < 0x3F ? 0x40 : 0x41
|
||
|
||
// 4. Return two bytes whose values are lead and trail + offset.
|
||
return [lead, trail + offset]
|
||
}
|
||
|
||
// 7. If gbk flag is set, return error with code point.
|
||
if (this.gbk_flag)
|
||
return encoderError(code_point)
|
||
|
||
// 8. Set pointer to the index gb18030 ranges pointer for code
|
||
// point.
|
||
pointer = indexGB18030RangesPointerFor(code_point)
|
||
|
||
// 9. Let byte1 be floor(pointer / 10 / 126 / 10).
|
||
var byte1 = floor(pointer / 10 / 126 / 10)
|
||
|
||
// 10. Set pointer to pointer − byte1 × 10 × 126 × 10.
|
||
pointer = pointer - byte1 * 10 * 126 * 10
|
||
|
||
// 11. Let byte2 be floor(pointer / 10 / 126).
|
||
var byte2 = floor(pointer / 10 / 126)
|
||
|
||
// 12. Set pointer to pointer − byte2 × 10 × 126.
|
||
pointer = pointer - byte2 * 10 * 126
|
||
|
||
// 13. Let byte3 be floor(pointer / 10).
|
||
var byte3 = floor(pointer / 10)
|
||
|
||
// 14. Let byte4 be pointer − byte3 × 10.
|
||
var byte4 = pointer - byte3 * 10
|
||
|
||
// 15. Return four bytes whose values are byte1 + 0x81, byte2 +
|
||
// 0x30, byte3 + 0x81, byte4 + 0x30.
|
||
return [byte1 + 0x81,
|
||
byte2 + 0x30,
|
||
byte3 + 0x81,
|
||
byte4 + 0x30]
|
||
}
|
||
|
||
constructor(options = {}, gbk_flag = false) {
|
||
// gb18030's decoder has an associated gbk flag (initially unset).
|
||
this.gbk_flag = gbk_flag
|
||
}
|
||
}
|