https://github.com/yamachu/LibOpenJTalk をNode.jsから呼び出すやつの下書き

libopenjtalk.ts

import { Library } from 'ffi-napi';
import ArrayType from 'ref-array-napi';
import {
  alloc,
  allocCString,
  readCString,
  refType,
  sizeof,
  types,
} from 'ref-napi';

// typedef
const typeofOpenJTalkInstance = types.void;
const typeofPtrOfOpenJTalkInstance = refType(typeofOpenJTalkInstance);
const intPtr = refType('int');
const stringPtr = refType('string');
const stringPtrPtr = refType(stringPtr);
const stringPtrArray = ArrayType(stringPtr);

// Open library once
const libopenjtalk = Library('libopenjtalk-lang', {
  Open_JTalk_initialize: [typeofPtrOfOpenJTalkInstance, []],
  Open_JTalk_clear: ['void', [typeofPtrOfOpenJTalkInstance]],
  Open_JTalk_load_u16: ['int', [typeofPtrOfOpenJTalkInstance, 'string']],
  Open_JTalk_extract_label_u16: [
    'int',
    [typeofPtrOfOpenJTalkInstance, 'string', stringPtrPtr, intPtr],
  ],
});

export const initialize = (dictPath: string) => {
  const openjtalkInstancePointer = libopenjtalk.Open_JTalk_initialize();
  if (openjtalkInstancePointer.isNull()) {
    throw new Error('Cannot Initialize LibOpenJTalk');
  }

  const dictPathUnicode = allocCString(dictPath, 'utf16le');

  const loaded =
    libopenjtalk.Open_JTalk_load_u16(
      openjtalkInstancePointer,
      dictPathUnicode as any /* 型が合わないけど、文字コードを指定するにはこれ以外の方法が見当たらなかった */
    ) == 1;
  dictPathUnicode.deref();

  if (!loaded) {
    libopenjtalk.Open_JTalk_clear(openjtalkInstancePointer);
    throw new Error('Cannot Load dict');
  }

  return {
    extractLabel: (text: string) => {
      const refLengthInt = alloc('int');
      const refStringPointer = alloc(stringPtrPtr);
      const textUnicode = allocCString(text, 'utf16le');
      const succeeded =
        libopenjtalk.Open_JTalk_extract_label_u16(
          openjtalkInstancePointer,
          textUnicode as any,
          refStringPointer,
          refLengthInt as any
        ) === 1;

      textUnicode.deref();
      const labelArrayLength = refLengthInt.deref();
      const labelsPointer = refStringPointer.deref();
      const labelsPointerArray = new stringPtrArray(
        labelsPointer.reinterpret(sizeof.pointer * labelArrayLength)
      );

      if (!succeeded) {
        return [];
      }

      return [...Array(labelArrayLength)]
        .map((_, i) => i)
        .map((i) => readCString(labelsPointerArray[i] as any));
    },
    destroy: () => {
      libopenjtalk.Open_JTalk_clear(openjtalkInstancePointer);
    },
  };
};