@zxing/text-encoding
Version:
Polyfill for the Encoding Living Standard's API.
270 lines • 12.6 kB
JavaScript
import { decoderError } from "../../encoding/encodings";
import { finished } from "../../encoding/finished";
import { index, indexCodePointFor } from "../../encoding/indexes";
import { end_of_stream } from "../../encoding/terminology";
import { inRange } from "../../encoding/utilities";
var states;
(function (states) {
states[states["ASCII"] = 0] = "ASCII";
states[states["Roman"] = 1] = "Roman";
states[states["Katakana"] = 2] = "Katakana";
states[states["LeadByte"] = 3] = "LeadByte";
states[states["TrailByte"] = 4] = "TrailByte";
states[states["EscapeStart"] = 5] = "EscapeStart";
states[states["Escape"] = 6] = "Escape";
})(states || (states = {}));
var ISO2022JPDecoder = /** @class */ (function () {
/**
* @constructor
* @implements {Decoder}
* @param {{fatal: boolean}} options
*/
function ISO2022JPDecoder(options) {
this.fatal = options.fatal;
// iso-2022-jp's decoder has an associated iso-2022-jp decoder
// state (initially ASCII), iso-2022-jp decoder output state
// (initially ASCII), iso-2022-jp lead (initially 0x00), and
// iso-2022-jp output flag (initially unset).
/** @type {number} */ this.iso2022jp_decoder_state = states.ASCII,
/** @type {number} */ this.iso2022jp_decoder_output_state = states.ASCII,
/** @type {number} */ this.iso2022jp_lead = 0x00,
/** @type {boolean} */ this.iso2022jp_output_flag = false;
}
/**
* @param {Stream} stream The stream of bytes being decoded.
* @param {number} bite The next byte read from the stream.
* @return {?(number|!Array.<number>)} The next code point(s)
* decoded, or null if not enough data exists in the input
* stream to decode a complete code point.
*/
ISO2022JPDecoder.prototype.handler = function (stream, bite) {
// switching on iso-2022-jp decoder state:
switch (this.iso2022jp_decoder_state) {
default:
case states.ASCII:
// ASCII
// Based on byte:
// 0x1B
if (bite === 0x1B) {
// Set iso-2022-jp decoder state to escape start and return
// continue.
this.iso2022jp_decoder_state = states.EscapeStart;
return null;
}
// 0x00 to 0x7F, excluding 0x0E, 0x0F, and 0x1B
if (inRange(bite, 0x00, 0x7F) && bite !== 0x0E
&& bite !== 0x0F && bite !== 0x1B) {
// Unset the iso-2022-jp output flag and return a code point
// whose value is byte.
this.iso2022jp_output_flag = false;
return bite;
}
// end-of-stream
if (bite === end_of_stream) {
// Return finished.
return finished;
}
// Otherwise
// Unset the iso-2022-jp output flag and return error.
this.iso2022jp_output_flag = false;
return decoderError(this.fatal);
case states.Roman:
// Roman
// Based on byte:
// 0x1B
if (bite === 0x1B) {
// Set iso-2022-jp decoder state to escape start and return
// continue.
this.iso2022jp_decoder_state = states.EscapeStart;
return null;
}
// 0x5C
if (bite === 0x5C) {
// Unset the iso-2022-jp output flag and return code point
// U+00A5.
this.iso2022jp_output_flag = false;
return 0x00A5;
}
// 0x7E
if (bite === 0x7E) {
// Unset the iso-2022-jp output flag and return code point
// U+203E.
this.iso2022jp_output_flag = false;
return 0x203E;
}
// 0x00 to 0x7F, excluding 0x0E, 0x0F, 0x1B, 0x5C, and 0x7E
if (inRange(bite, 0x00, 0x7F) && bite !== 0x0E && bite !== 0x0F
&& bite !== 0x1B && bite !== 0x5C && bite !== 0x7E) {
// Unset the iso-2022-jp output flag and return a code point
// whose value is byte.
this.iso2022jp_output_flag = false;
return bite;
}
// end-of-stream
if (bite === end_of_stream) {
// Return finished.
return finished;
}
// Otherwise
// Unset the iso-2022-jp output flag and return error.
this.iso2022jp_output_flag = false;
return decoderError(this.fatal);
case states.Katakana:
// Katakana
// Based on byte:
// 0x1B
if (bite === 0x1B) {
// Set iso-2022-jp decoder state to escape start and return
// continue.
this.iso2022jp_decoder_state = states.EscapeStart;
return null;
}
// 0x21 to 0x5F
if (inRange(bite, 0x21, 0x5F)) {
// Unset the iso-2022-jp output flag and return a code point
// whose value is 0xFF61 − 0x21 + byte.
this.iso2022jp_output_flag = false;
return 0xFF61 - 0x21 + bite;
}
// end-of-stream
if (bite === end_of_stream) {
// Return finished.
return finished;
}
// Otherwise
// Unset the iso-2022-jp output flag and return error.
this.iso2022jp_output_flag = false;
return decoderError(this.fatal);
case states.LeadByte:
// Lead byte
// Based on byte:
// 0x1B
if (bite === 0x1B) {
// Set iso-2022-jp decoder state to escape start and return
// continue.
this.iso2022jp_decoder_state = states.EscapeStart;
return null;
}
// 0x21 to 0x7E
if (inRange(bite, 0x21, 0x7E)) {
// Unset the iso-2022-jp output flag, set iso-2022-jp lead
// to byte, iso-2022-jp decoder state to trail byte, and
// return continue.
this.iso2022jp_output_flag = false;
this.iso2022jp_lead = bite;
this.iso2022jp_decoder_state = states.TrailByte;
return null;
}
// end-of-stream
if (bite === end_of_stream) {
// Return finished.
return finished;
}
// Otherwise
// Unset the iso-2022-jp output flag and return error.
this.iso2022jp_output_flag = false;
return decoderError(this.fatal);
case states.TrailByte:
// Trail byte
// Based on byte:
// 0x1B
if (bite === 0x1B) {
// Set iso-2022-jp decoder state to escape start and return
// continue.
this.iso2022jp_decoder_state = states.EscapeStart;
return decoderError(this.fatal);
}
// 0x21 to 0x7E
if (inRange(bite, 0x21, 0x7E)) {
// 1. Set the iso-2022-jp decoder state to lead byte.
this.iso2022jp_decoder_state = states.LeadByte;
// 2. Let pointer be (iso-2022-jp lead − 0x21) × 94 + byte − 0x21.
var pointer = (this.iso2022jp_lead - 0x21) * 94 + bite - 0x21;
// 3. Let code point be the index code point for pointer in
// index jis0208.
var code_point = indexCodePointFor(pointer, index('jis0208'));
// 4. If code point is null, return error.
if (code_point === null)
return decoderError(this.fatal);
// 5. Return a code point whose value is code point.
return code_point;
}
// end-of-stream
if (bite === end_of_stream) {
// Set the iso-2022-jp decoder state to lead byte, prepend
// byte to stream, and return error.
this.iso2022jp_decoder_state = states.LeadByte;
stream.prepend(bite);
return decoderError(this.fatal);
}
// Otherwise
// Set iso-2022-jp decoder state to lead byte and return
// error.
this.iso2022jp_decoder_state = states.LeadByte;
return decoderError(this.fatal);
case states.EscapeStart:
// Escape start
// 1. If byte is either 0x24 or 0x28, set iso-2022-jp lead to
// byte, iso-2022-jp decoder state to escape, and return
// continue.
if (bite === 0x24 || bite === 0x28) {
this.iso2022jp_lead = bite;
this.iso2022jp_decoder_state = states.Escape;
return null;
}
// 2. Prepend byte to stream.
stream.prepend(bite);
// 3. Unset the iso-2022-jp output flag, set iso-2022-jp
// decoder state to iso-2022-jp decoder output state, and
// return error.
this.iso2022jp_output_flag = false;
this.iso2022jp_decoder_state = this.iso2022jp_decoder_output_state;
return decoderError(this.fatal);
case states.Escape:
// Escape
// 1. Let lead be iso-2022-jp lead and set iso-2022-jp lead to
// 0x00.
var lead = this.iso2022jp_lead;
this.iso2022jp_lead = 0x00;
// 2. Let state be null.
var state = null;
// 3. If lead is 0x28 and byte is 0x42, set state to ASCII.
if (lead === 0x28 && bite === 0x42)
state = states.ASCII;
// 4. If lead is 0x28 and byte is 0x4A, set state to Roman.
if (lead === 0x28 && bite === 0x4A)
state = states.Roman;
// 5. If lead is 0x28 and byte is 0x49, set state to Katakana.
if (lead === 0x28 && bite === 0x49)
state = states.Katakana;
// 6. If lead is 0x24 and byte is either 0x40 or 0x42, set
// state to lead byte.
if (lead === 0x24 && (bite === 0x40 || bite === 0x42))
state = states.LeadByte;
// 7. If state is non-null, run these substeps:
if (state !== null) {
// 1. Set iso-2022-jp decoder state and iso-2022-jp decoder
// output state to states.
this.iso2022jp_decoder_state = this.iso2022jp_decoder_state = state;
// 2. Let output flag be the iso-2022-jp output flag.
var output_flag = this.iso2022jp_output_flag;
// 3. Set the iso-2022-jp output flag.
this.iso2022jp_output_flag = true;
// 4. Return continue, if output flag is unset, and error
// otherwise.
return !output_flag ? null : decoderError(this.fatal);
}
// 8. Prepend lead and byte to stream.
stream.prepend([lead, bite]);
// 9. Unset the iso-2022-jp output flag, set iso-2022-jp
// decoder state to iso-2022-jp decoder output state and
// return error.
this.iso2022jp_output_flag = false;
this.iso2022jp_decoder_state = this.iso2022jp_decoder_output_state;
return decoderError(this.fatal);
}
};
return ISO2022JPDecoder;
}());
export { ISO2022JPDecoder };
//# sourceMappingURL=ISO2022JPDecoder.js.map