node.js中的buffer.write方法使用说明

  if (string.length > 0 && (length < 0 || offset < 0))
    throw new RangeError(‘attempt to write beyond buffer bounds’);
  var ret;
  switch (encoding) {
    case ‘hex’:
      ret = this.hexWrite(string, offset, length);
      break;
    case ‘utf8’:
    case ‘utf-8’:
      ret = this.utf8Write(string, offset, length);
      break;
    case ‘ascii’:
      ret = this.asciiWrite(string, offset, length);
      break;
    case ‘binary’:
      ret = this.binaryWrite(string, offset, length);
      break;
    case ‘base64’:
      // Warning: maxLength not taken into account in base64Write
      ret = this.base64Write(string, offset, length);
      break;
    case ‘ucs2’:
    case ‘ucs-2’:
    case ‘utf16le’:
    case ‘utf-16le’:
      ret = this.ucs2Write(string, offset, length);
      break;
    default:
      throw new TypeError(‘Unknown encoding: ‘ + encoding);
  }
  return ret;
};