chat-server/qq-imsvr/node_modules/crc/lib/crc1.js

'use strict';

var _buffer = require('buffer');

var _define_crc = require('./define_crc');

var _define_crc2 = _interopRequireDefault(_define_crc);

function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }

module.exports = (0, _define_crc2.default)('crc1', function (buf, previous) {
  if (!_buffer.Buffer.isBuffer(buf)) buf = (0, _buffer.Buffer)(buf);

  var crc = ~ ~previous;
  var accum = 0;

  for (var index = 0; index < buf.length; index++) {
    var byte = buf[index];
    accum += byte;
  }

  crc += accum % 256;
  return crc % 256;
});