@zxing/text-encoding
Version:
Polyfill for the Encoding Living Standard's API.
48 lines • 1.98 kB
JavaScript
import { encoderError } from "../../encoding/encodings";
import { finished } from "../../encoding/finished";
import { indexBig5PointerFor } from "../../encoding/indexes";
import { end_of_stream, isASCIICodePoint } from "../../encoding/terminology";
/**
* @constructor
* @implements {Encoder}
* @param {{fatal: boolean}} options
*/
var Big5Encoder = /** @class */ (function () {
function Big5Encoder(options) {
this.fatal = options.fatal;
}
/**
* @param {Stream} stream Input stream.
* @param {number} code_point Next code point read from the stream.
* @return {(number|!Array.<number>)} Byte(s) to emit.
*/
Big5Encoder.prototype.handler = function (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. Let pointer be the index Big5 pointer for code point.
var pointer = indexBig5PointerFor(code_point);
// 4. If pointer is null, return error with code point.
if (pointer === null)
return encoderError(code_point);
// 5. Let lead be Math.floor(pointer / 157) + 0x81.
var lead = Math.floor(pointer / 157) + 0x81;
// 6. If lead is less than 0xA1, return error with code point.
if (lead < 0xA1)
return encoderError(code_point);
// 7. Let trail be pointer % 157.
var trail = pointer % 157;
// 8. Let offset be 0x40 if trail is less than 0x3F and 0x62
// otherwise.
var offset = trail < 0x3F ? 0x40 : 0x62;
// Return two bytes whose values are lead and trail + offset.
return [lead, trail + offset];
};
return Big5Encoder;
}());
export { Big5Encoder };
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