如何实现ArkTS与C/C++的数组转换？

Question

如题：如何实现ArkTS与C/C++的数组转换？

Answer 1

TS2NAPI

TS侧

Button("TS2NAPI")
  .fontSize(50)
  .fontWeight(FontWeight.Bold)
  .onClick(() => {
    let napiArray: Int32Array = new Int32Array([0, 1, 2, 3, 4, 5, 6, 7, 8, 9])
    console.info("TS2NAPI: JS   " + napiArray)
    testNapi.TS2NAPI(napiArray)
  })

NAPI侧

// TS array 传到NAPI层
static napi_value TS2NAPI(napi_env env, napi_callback_info info) {
  // 获取TS层传来的参数
  size_t argc = 1;
  napi_value args;
  napi_get_cb_info(env, info, &argc, &args, NULL, NULL);
  napi_value input_array = args;

  // 获取传入数组typedarray生成input_buffer
  napi_typedarray_type type; // 数据类型
  napi_value input_buffer;
  size_t byte_offset; // 数据偏移
  size_t i, length;   // 数据字节大小
  napi_get_typedarray_info(env, input_array, &type, &length, NULL, &input_buffer, &byte_offset);

  // 获取数组数据
  void *data;
  size_t byte_length;
  napi_get_arraybuffer_info(env, input_buffer, &data, &byte_length);

  if (type == napi_int32_array) {
    int32_t *data_bytes = (int32_t *)(data);
    int32_t num = length / sizeof(int32_t);

    string str = "";
    for (int32_t i = 0; i < num; i++) {
      int32_t tmp = *((int32_t *)(data_bytes) + i);
      str += (to_string(tmp) + ' ');
    }
    OH_LOG_INFO(LOG_APP, "TS2NAPI: C++  %{public}s", str.c_str());
  }

  return NULL;
}

NAPI2TS

TS侧

Button("NAPI2TS")
  .fontSize(50)
  .fontWeight(FontWeight.Bold)
  .onClick(() => {
    let napiArray: Int32Array = testNapi.NAPI2TS()
    console.info("NAPI2TS: JS   " + napiArray)
  })

NAPI侧

// NAPI层 array 传到TS层
static napi_value NAPI2TS(napi_env env, napi_callback_info info) {
  // 数据个数
  int num = 10;

  // 创建output_buffer
  napi_value output_buffer;
  void *output_ptr = NULL;
  napi_create_arraybuffer(env, num * sizeof(int32_t), &output_ptr, &output_buffer);

  // output_array
  napi_value output_array;
  napi_create_typedarray(env, napi_int32_array, num, output_buffer, 0, &output_array);

  // 给output_ptr、output_buffer赋值
  int32_t *output_bytes = (int32_t *)output_ptr;
  for (int32_t i = 0; i < num; i++) {
    output_bytes[i] = i;
  }

  string str = "";
  for (int32_t i = 0; i < num; i++) {
    int32_t tmp = *((int32_t *)(output_ptr) + i);
    str += (to_string(tmp) + ' ');
  }
  OH_LOG_INFO(LOG_APP, "NAPI2TS: C++  %{public}s", str.c_str());

  return output_array;
}

实用场景：

ArkTS侧读取rawfile的图片，传递到NAPI侧进行处理；

然后传回ArkTS进行展示。

Button("Test")
  .fontSize(50)
  .fontWeight(FontWeight.Bold)
  .onClick(() => {

    getContext().resourceManager.getRawFileContent('test.png').then(value => {
      hilog.info(0x0000, 'getRawFileContent', '%{public}s', 'OK');
      const fileData: Uint8Array = value;
      // 获取图片的ArrayBuffer
      let buffer = fileData.buffer;

      let input = new Uint8Array(buffer)
      let output = testNapi.TEST(input);

      let decodingOptions: image.DecodingOptions = {
        editable: true,
        desiredPixelFormat: 3,
      }
      let imageSource = image.createImageSource(output.buffer);
      imageSource.createPixelMap(decodingOptions).then(map => {
        this.imageSrc = map;
      })
    }).catch((err: BusinessError) => {
      hilog.error(0x0000, 'getRawFileContent', '%{public}s', err.message);
    })
  })

Image(this.imageSrc)
  .height(100)
  .width(100)