@zxing/text-encoding
Version:
Polyfill for the Encoding Living Standard's API.
63 lines • 2.74 kB
JavaScript
import { encoderError } from "../../encoding/encodings";
import { finished } from "../../encoding/finished";
import { indexShiftJISPointerFor } from "../../encoding/indexes";
import { end_of_stream, isASCIICodePoint } from "../../encoding/terminology";
import { inRange } from "../../encoding/utilities";
/**
* @constructor
* @implements {Encoder}
* @param {{fatal: boolean}} options
*/
var ShiftJISEncoder = /** @class */ (function () {
function ShiftJISEncoder(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.
*/
ShiftJISEncoder.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 or U+0080, return a
// byte whose value is code point.
if (isASCIICodePoint(code_point) || code_point === 0x0080)
return code_point;
// 3. If code point is U+00A5, return byte 0x5C.
if (code_point === 0x00A5)
return 0x5C;
// 4. If code point is U+203E, return byte 0x7E.
if (code_point === 0x203E)
return 0x7E;
// 5. If code point is in the range U+FF61 to U+FF9F, inclusive,
// return a byte whose value is code point − 0xFF61 + 0xA1.
if (inRange(code_point, 0xFF61, 0xFF9F))
return code_point - 0xFF61 + 0xA1;
// 6. If code point is U+2212, set it to U+FF0D.
if (code_point === 0x2212)
code_point = 0xFF0D;
// 7. Let pointer be the index Shift_JIS pointer for code point.
var pointer = indexShiftJISPointerFor(code_point);
// 8. If pointer is null, return error with code point.
if (pointer === null)
return encoderError(code_point);
// 9. Let lead be Math.floor(pointer / 188).
var lead = Math.floor(pointer / 188);
// 10. Let lead offset be 0x81, if lead is less than 0x1F, and
// 0xC1 otherwise.
var lead_offset = (lead < 0x1F) ? 0x81 : 0xC1;
// 11. Let trail be pointer % 188.
var trail = pointer % 188;
// 12. Let offset be 0x40, if trail is less than 0x3F, and 0x41
// otherwise.
var offset = (trail < 0x3F) ? 0x40 : 0x41;
// 13. Return two bytes whose values are lead + lead offset and
// trail + offset.
return [lead + lead_offset, trail + offset];
};
return ShiftJISEncoder;
}());
export { ShiftJISEncoder };
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