@nuintun/qrcode/esm/encoder/segments/Kanji.js

A pure JavaScript QRCode encode and decode library.

/**
 * @module QRCode
 * @package @nuintun/qrcode
 * @license MIT
 * @version 5.0.2
 * @author nuintun <nuintun@qq.com>
 * @description A pure JavaScript QRCode encode and decode library.
 * @see https://github.com/nuintun/qrcode#readme
 */

import { Mode } from '../../common/Mode.js';
import { BitArray } from '../../common/BitArray.js';
import { assertContent } from '../utils/asserts.js';
import { SHIFT_JIS_MAPPING } from '../../common/encoding/mapping.js';

/**
 * @module Kanji
 */
function getKanjiCode(character) {
  const code = SHIFT_JIS_MAPPING.get(character);
  return code != null ? code : NaN;
}
class Kanji {
  #content;
  /**
   * @constructor
   * @param content The content to encode.
   */
  constructor(content) {
    assertContent(content);
    this.#content = content;
  }
  /**
   * @property mode
   * @description The mode of the segment.
   */
  get mode() {
    return Mode.KANJI;
  }
  /**
   * @property content
   * @description The content of the segment.
   */
  get content() {
    return this.#content;
  }
  /**
   * @method encode
   * @description Encode the segment.
   */
  encode() {
    const bits = new BitArray();
    const content = this.#content;
    for (const character of content) {
      let code = getKanjiCode(character);
      // For characters with Shift JIS values from 0x8140 to 0x9ffc.
      if (code >= 0x8140 && code <= 0x9ffc) {
        // Subtract 0x8140 from Shift JIS value.
        code -= 0x8140;
        // For characters with Shift JIS values from 0xe040 to 0xebbf.
      } else if (code >= 0xe040 && code <= 0xebbf) {
        // Subtract 0xc140 from Shift JIS value.
        code -= 0xc140;
      } else {
        throw new Error(`illegal kanji character: ${character}`);
      }
      // Multiply most significant byte of result by 0xc0 and add least significant byte to product.
      code = (code >> 8) * 0xc0 + (code & 0xff);
      // Convert result to a 13-bit binary string.
      bits.append(code, 13);
    }
    return bits;
  }
}

export { Kanji };