441 lines
14 KiB
JavaScript
441 lines
14 KiB
JavaScript
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import { inRange, decoderError, encoderError, isASCIICodePoint,
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end_of_stream, finished, floor } from './text_decoder_utils.js'
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import index, { indexCodePointFor, indexPointerFor } from './text_decoder_indexes.js'
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// 13.2 iso-2022-jp
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// 13.2.1 iso-2022-jp decoder
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/**
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* @implements {Decoder}
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*/
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export class ISO2022JPDecoder {
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constructor(options) {
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const { fatal } = options
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this.fatal = fatal
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/** @enum */
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this.states = {
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ASCII: 0,
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Roman: 1,
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Katakana: 2,
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LeadByte: 3,
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TrailByte: 4,
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EscapeStart: 5,
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Escape: 6,
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}
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// iso-2022-jp's decoder has an associated iso-2022-jp decoder
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// state (initially ASCII), iso-2022-jp decoder output state
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// (initially ASCII), iso-2022-jp lead (initially 0x00), and
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// iso-2022-jp output flag (initially unset).
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this.iso2022jp_decoder_state = this.states.ASCII
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this.iso2022jp_decoder_output_state = this.states.ASCII,
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this.iso2022jp_lead = 0x00
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this.iso2022jp_output_flag = false
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}
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/**
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* @param {Stream} stream The stream of bytes being decoded.
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* @param {number} bite The next byte read from the stream.
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*/
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handler(stream, bite) {
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// switching on iso-2022-jp decoder state:
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switch (this.iso2022jp_decoder_state) {
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default:
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case this.states.ASCII:
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// ASCII
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// Based on byte:
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// 0x1B
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if (bite === 0x1B) {
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// Set iso-2022-jp decoder state to escape start and return
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// continue.
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this.iso2022jp_decoder_state = this.states.EscapeStart
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return null
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}
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// 0x00 to 0x7F, excluding 0x0E, 0x0F, and 0x1B
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if (inRange(bite, 0x00, 0x7F) && bite !== 0x0E
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&& bite !== 0x0F && bite !== 0x1B) {
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// Unset the iso-2022-jp output flag and return a code point
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// whose value is byte.
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this.iso2022jp_output_flag = false
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return bite
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}
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// end-of-stream
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if (bite === end_of_stream) {
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// Return finished.
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return finished
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}
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// Otherwise
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// Unset the iso-2022-jp output flag and return error.
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this.iso2022jp_output_flag = false
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return decoderError(this.fatal)
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case this.states.Roman:
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// Roman
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// Based on byte:
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// 0x1B
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if (bite === 0x1B) {
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// Set iso-2022-jp decoder state to escape start and return
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// continue.
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this.iso2022jp_decoder_state = this.states.EscapeStart
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return null
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}
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// 0x5C
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if (bite === 0x5C) {
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// Unset the iso-2022-jp output flag and return code point
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// U+00A5.
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this.iso2022jp_output_flag = false
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return 0x00A5
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}
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// 0x7E
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if (bite === 0x7E) {
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// Unset the iso-2022-jp output flag and return code point
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// U+203E.
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this.iso2022jp_output_flag = false
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return 0x203E
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}
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// 0x00 to 0x7F, excluding 0x0E, 0x0F, 0x1B, 0x5C, and 0x7E
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if (inRange(bite, 0x00, 0x7F) && bite !== 0x0E && bite !== 0x0F
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&& bite !== 0x1B && bite !== 0x5C && bite !== 0x7E) {
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// Unset the iso-2022-jp output flag and return a code point
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// whose value is byte.
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this.iso2022jp_output_flag = false
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return bite
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}
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// end-of-stream
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if (bite === end_of_stream) {
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// Return finished.
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return finished
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}
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// Otherwise
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// Unset the iso-2022-jp output flag and return error.
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this.iso2022jp_output_flag = false
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return decoderError(this.fatal)
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case this.states.Katakana:
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// Katakana
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// Based on byte:
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// 0x1B
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if (bite === 0x1B) {
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// Set iso-2022-jp decoder state to escape start and return
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// continue.
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this.iso2022jp_decoder_state = this.states.EscapeStart
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return null
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}
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// 0x21 to 0x5F
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if (inRange(bite, 0x21, 0x5F)) {
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// Unset the iso-2022-jp output flag and return a code point
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// whose value is 0xFF61 − 0x21 + byte.
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this.iso2022jp_output_flag = false
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return 0xFF61 - 0x21 + bite
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}
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// end-of-stream
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if (bite === end_of_stream) {
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// Return finished.
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return finished
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}
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// Otherwise
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// Unset the iso-2022-jp output flag and return error.
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this.iso2022jp_output_flag = false
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return decoderError(this.fatal)
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case this.states.LeadByte:
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// Lead byte
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// Based on byte:
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// 0x1B
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if (bite === 0x1B) {
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// Set iso-2022-jp decoder state to escape start and return
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// continue.
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this.iso2022jp_decoder_state = this.states.EscapeStart
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return null
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}
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// 0x21 to 0x7E
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if (inRange(bite, 0x21, 0x7E)) {
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// Unset the iso-2022-jp output flag, set iso-2022-jp lead
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// to byte, iso-2022-jp decoder state to trail byte, and
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// return continue.
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this.iso2022jp_output_flag = false
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this.iso2022jp_lead = bite
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this.iso2022jp_decoder_state = this.states.TrailByte
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return null
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}
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// end-of-stream
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if (bite === end_of_stream) {
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// Return finished.
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return finished
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}
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// Otherwise
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// Unset the iso-2022-jp output flag and return error.
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this.iso2022jp_output_flag = false
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return decoderError(this.fatal)
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case this.states.TrailByte:
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// Trail byte
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// Based on byte:
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// 0x1B
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if (bite === 0x1B) {
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// Set iso-2022-jp decoder state to escape start and return
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// continue.
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this.iso2022jp_decoder_state = this.states.EscapeStart
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return decoderError(this.fatal)
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}
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// 0x21 to 0x7E
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if (inRange(bite, 0x21, 0x7E)) {
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// 1. Set the iso-2022-jp decoder state to lead byte.
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this.iso2022jp_decoder_state = this.states.LeadByte
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// 2. Let pointer be (iso-2022-jp lead − 0x21) × 94 + byte − 0x21.
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const pointer = (this.iso2022jp_lead - 0x21) * 94 + bite - 0x21
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// 3. Let code point be the index code point for pointer in
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// index jis0208.
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const code_point = indexCodePointFor(pointer, index('jis0208'))
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// 4. If code point is null, return error.
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if (code_point === null)
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return decoderError(this.fatal)
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// 5. Return a code point whose value is code point.
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return code_point
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}
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// end-of-stream
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if (bite === end_of_stream) {
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// Set the iso-2022-jp decoder state to lead byte, prepend
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// byte to stream, and return error.
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this.iso2022jp_decoder_state = this.states.LeadByte
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stream.prepend(bite)
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return decoderError(this.fatal)
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}
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// Otherwise
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// Set iso-2022-jp decoder state to lead byte and return
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// error.
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this.iso2022jp_decoder_state = this.states.LeadByte
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return decoderError(this.fatal)
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case this.states.EscapeStart:
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// Escape start
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// 1. If byte is either 0x24 or 0x28, set iso-2022-jp lead to
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// byte, iso-2022-jp decoder state to escape, and return
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// continue.
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if (bite === 0x24 || bite === 0x28) {
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this.iso2022jp_lead = bite
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this.iso2022jp_decoder_state = this.states.Escape
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return null
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}
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// 2. Prepend byte to stream.
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stream.prepend(bite)
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// 3. Unset the iso-2022-jp output flag, set iso-2022-jp
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// decoder state to iso-2022-jp decoder output state, and
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// return error.
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this.iso2022jp_output_flag = false
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this.iso2022jp_decoder_state = this.iso2022jp_decoder_output_state
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return decoderError(this.fatal)
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case this.states.Escape: {
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// Escape
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// 1. Let lead be iso-2022-jp lead and set iso-2022-jp lead to
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// 0x00.
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const lead = this.iso2022jp_lead
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this.iso2022jp_lead = 0x00
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// 2. Let state be null.
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let state = null
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// 3. If lead is 0x28 and byte is 0x42, set state to ASCII.
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if (lead === 0x28 && bite === 0x42)
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state = this.states.ASCII
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// 4. If lead is 0x28 and byte is 0x4A, set state to Roman.
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if (lead === 0x28 && bite === 0x4A)
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state = this.states.Roman
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// 5. If lead is 0x28 and byte is 0x49, set state to Katakana.
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if (lead === 0x28 && bite === 0x49)
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state = this.states.Katakana
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// 6. If lead is 0x24 and byte is either 0x40 or 0x42, set
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// state to lead byte.
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if (lead === 0x24 && (bite === 0x40 || bite === 0x42))
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state = this.states.LeadByte
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// 7. If state is non-null, run these substeps:
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if (state !== null) {
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// 1. Set iso-2022-jp decoder state and iso-2022-jp decoder
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// output state to this.states.
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this.iso2022jp_decoder_state = this.iso2022jp_decoder_state = state
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// 2. Let output flag be the iso-2022-jp output flag.
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const output_flag = this.iso2022jp_output_flag
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// 3. Set the iso-2022-jp output flag.
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this.iso2022jp_output_flag = true
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// 4. Return continue, if output flag is unset, and error
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// otherwise.
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return !output_flag ? null : decoderError(this.fatal)
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}
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// 8. Prepend lead and byte to stream.
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stream.prepend([lead, bite])
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// 9. Unset the iso-2022-jp output flag, set iso-2022-jp
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// decoder state to iso-2022-jp decoder output state and
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// return error.
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this.iso2022jp_output_flag = false
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this.iso2022jp_decoder_state = this.iso2022jp_decoder_output_state
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return decoderError(this.fatal)
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}
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}
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}
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}
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// 13.2.2 iso-2022-jp encoder
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/**
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* @implements {Encoder}
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*/
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export class ISO2022JPEncoder {
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constructor() {
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// iso-2022-jp's encoder has an associated iso-2022-jp encoder
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// state which is one of ASCII, Roman, and jis0208 (initially
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// ASCII).
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/** @enum */
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this.states = {
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ASCII: 0,
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Roman: 1,
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jis0208: 2,
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}
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this.iso2022jp_state = this.states.ASCII
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}
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/**
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* @param {Stream} stream Input stream.
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* @param {number} code_point Next code point read from the stream.
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*/
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handler(stream, code_point) {
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// 1. If code point is end-of-stream and iso-2022-jp encoder
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// state is not ASCII, prepend code point to stream, set
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// iso-2022-jp encoder state to ASCII, and return three bytes
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// 0x1B 0x28 0x42.
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if (code_point === end_of_stream &&
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this.iso2022jp_state !== this.states.ASCII) {
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stream.prepend(code_point)
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this.iso2022jp_state = this.states.ASCII
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return [0x1B, 0x28, 0x42]
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}
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// 2. If code point is end-of-stream and iso-2022-jp encoder
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// state is ASCII, return finished.
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if (code_point === end_of_stream && this.iso2022jp_state === this.states.ASCII)
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return finished
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// 3. If ISO-2022-JP encoder state is ASCII or Roman, and code
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|
|
// point is U+000E, U+000F, or U+001B, return error with U+FFFD.
|
|||
|
|
if ((this.iso2022jp_state === this.states.ASCII ||
|
|||
|
|
this.iso2022jp_state === this.states.Roman) &&
|
|||
|
|
(code_point === 0x000E || code_point === 0x000F ||
|
|||
|
|
code_point === 0x001B)) {
|
|||
|
|
return encoderError(0xFFFD)
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 4. If iso-2022-jp encoder state is ASCII and code point is an
|
|||
|
|
// ASCII code point, return a byte whose value is code point.
|
|||
|
|
if (this.iso2022jp_state === this.states.ASCII &&
|
|||
|
|
isASCIICodePoint(code_point))
|
|||
|
|
return code_point
|
|||
|
|
|
|||
|
|
// 5. If iso-2022-jp encoder state is Roman and code point is an
|
|||
|
|
// ASCII code point, excluding U+005C and U+007E, or is U+00A5
|
|||
|
|
// or U+203E, run these substeps:
|
|||
|
|
if (this.iso2022jp_state === this.states.Roman &&
|
|||
|
|
((isASCIICodePoint(code_point) &&
|
|||
|
|
code_point !== 0x005C && code_point !== 0x007E) ||
|
|||
|
|
(code_point == 0x00A5 || code_point == 0x203E))) {
|
|||
|
|
// 1. If code point is an ASCII code point, return a byte
|
|||
|
|
// whose value is code point.
|
|||
|
|
if (isASCIICodePoint(code_point))
|
|||
|
|
return code_point
|
|||
|
|
|
|||
|
|
// 2. If code point is U+00A5, return byte 0x5C.
|
|||
|
|
if (code_point === 0x00A5)
|
|||
|
|
return 0x5C
|
|||
|
|
|
|||
|
|
// 3. If code point is U+203E, return byte 0x7E.
|
|||
|
|
if (code_point === 0x203E)
|
|||
|
|
return 0x7E
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 6. If code point is an ASCII code point, and iso-2022-jp
|
|||
|
|
// encoder state is not ASCII, prepend code point to stream, set
|
|||
|
|
// iso-2022-jp encoder state to ASCII, and return three bytes
|
|||
|
|
// 0x1B 0x28 0x42.
|
|||
|
|
if (isASCIICodePoint(code_point) &&
|
|||
|
|
this.iso2022jp_state !== this.states.ASCII) {
|
|||
|
|
stream.prepend(code_point)
|
|||
|
|
this.iso2022jp_state = this.states.ASCII
|
|||
|
|
return [0x1B, 0x28, 0x42]
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 7. If code point is either U+00A5 or U+203E, and iso-2022-jp
|
|||
|
|
// encoder state is not Roman, prepend code point to stream, set
|
|||
|
|
// iso-2022-jp encoder state to Roman, and return three bytes
|
|||
|
|
// 0x1B 0x28 0x4A.
|
|||
|
|
if ((code_point === 0x00A5 || code_point === 0x203E) &&
|
|||
|
|
this.iso2022jp_state !== this.states.Roman) {
|
|||
|
|
stream.prepend(code_point)
|
|||
|
|
this.iso2022jp_state = this.states.Roman
|
|||
|
|
return [0x1B, 0x28, 0x4A]
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 8. If code point is U+2212, set it to U+FF0D.
|
|||
|
|
if (code_point === 0x2212)
|
|||
|
|
code_point = 0xFF0D
|
|||
|
|
|
|||
|
|
// 9. Let pointer be the index pointer for code point in index
|
|||
|
|
// jis0208.
|
|||
|
|
const pointer = indexPointerFor(code_point, index('jis0208'))
|
|||
|
|
|
|||
|
|
// 10. If pointer is null, return error with code point.
|
|||
|
|
if (pointer === null)
|
|||
|
|
return encoderError(code_point)
|
|||
|
|
|
|||
|
|
// 11. If iso-2022-jp encoder state is not jis0208, prepend code
|
|||
|
|
// point to stream, set iso-2022-jp encoder state to jis0208,
|
|||
|
|
// and return three bytes 0x1B 0x24 0x42.
|
|||
|
|
if (this.iso2022jp_state !== this.states.jis0208) {
|
|||
|
|
stream.prepend(code_point)
|
|||
|
|
this.iso2022jp_state = this.states.jis0208
|
|||
|
|
return [0x1B, 0x24, 0x42]
|
|||
|
|
}
|
|||
|
|
|
|||
|
|
// 12. Let lead be floor(pointer / 94) + 0x21.
|
|||
|
|
const lead = floor(pointer / 94) + 0x21
|
|||
|
|
|
|||
|
|
// 13. Let trail be pointer % 94 + 0x21.
|
|||
|
|
const trail = pointer % 94 + 0x21
|
|||
|
|
|
|||
|
|
// 14. Return two bytes whose values are lead and trail.
|
|||
|
|
return [lead, trail]
|
|||
|
|
}
|
|||
|
|
}
|