egg-thing-parser/lib/tlv/transfer/exception.js

thing model parser

'use strict';

const BaseTransfer = require('./baseTransfer');
const thingAssert = require('thing-assert');

/**
 * Exception解析
 *
 * @class ExceptionParse
 * @extends {BaseTransfer}
 */
class ExceptionParse extends BaseTransfer {
  /**
   *Creates an instance of ExceptionParse.
   * @memberof ExceptionParse
   */
  constructor() {
    super('EXCEPTION');
  }

  typeToBinary(value) {
    const buffer = Buffer.allocUnsafe(4);
    buffer.writeUInt32BE(value);
    return buffer;
  }
  /**
   * exception buffer => exception value
   *
   * @param {Buffer} binary - buffer
   * @return {Array} array value
   * @memberof ExceptionParse
   */
  binaryToType(binary) {
    thingAssert(Buffer.isBuffer(binary), `[ExceptionParse][binaryToType] - 数据类型错误，需为二进制: ${binary}`, 400);
    thingAssert(binary.length === 4, `[ExceptionParse][binaryToType] - 数据错误，长度需为4字节，实际为: ${binary.length}`, 400);

    const index = [];
    const value = binary.readUInt32BE();
    const str = value.toString(2);
    for (let i = str.length - 1; i >= 0; i--) {
      if (parseInt(str[i]) === 1) {
        index.push(str.length - i - 1);
      }
    }
    return index.toString();
  }
}
module.exports = ExceptionParse;