Variant Streaming Code

.

Overview

This code provides two global functions, WriteVariantToStream and ReadVariantFromStream, that enable you to read and write a variant to a stream. In addition, there are two other global functions, ReadVariantFromBlob and WriteVariantToBlob, for reading and writing a variant to a BLOB.

Highlights

Here are some of the main advantages of these functions:
  • Uses any given IStream to stream the Variant into and out of.
  • Data is streamed in efficient binary form.
  • Stream is versioned for backwards compatibility.
  • Supports arbitrary size and arbitrary dimension safe-arrays.
  • Object streaming is supported if the object in variant supports IPersistStream[Init].
  • All code is in one header file (VariantStream.h) and only two routines are exposed: WriteVariantToStream and ReadVariantFromStream.
  • Comes with supporting test code that tests the header file -- in case code is modified
  • Does not use C++ exception handling.  Test project has EH flag turned..
  • Doesn't use the CRT.
  • Does not use any Direct-To-COM (VC++'s comdef.h, such as _variant_t, _bstr_t, _com_ptr, _com_error)
  • Works in both Unicode and ANSI

Downloads

Download source - 37 Kb


Comments

  • There may be a way to do this using VARIANT_UserMarshal, VARIANT_UserUnmarshal

    Posted by kasajian on 01/14/2010 05:14pm

    It may be possible to do this using these functions: VARIANT_UserMarshal VARIANT_UserUnmarshal

    Reply
  • The hope page for this code

    Posted by kasajian on 08/23/2007 12:31pm

    http://kasajian.com/VariantStream.html

    Reply
  • Excellent!

    Posted by Legacy on 01/09/2003 12:00am

    Originally posted by: Greg Holt

    Very well thought out code. Very clean and easy to understand. I don't understand why Microsoft doesn't provide this functionality.

    Only enhancement that I would like to see (and will probably end up writing it myself) is the ability to use BLOB data instead of an IStream. I know that you can use StreamToTaskMemory and BlobToStream but I don't want the overhead of having to always create a Stream everytime I want to write/read a variant.

    Reply
Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Live Event Date: December 11, 2014 @ 1:00 p.m. ET / 10:00 a.m. PT Market pressures to move more quickly and develop innovative applications are forcing organizations to rethink how they develop and release applications. The combination of public clouds and physical back-end infrastructures are a means to get applications out faster. However, these hybrid solutions complicate DevOps adoption, with application delivery pipelines that span across complex hybrid cloud and non-cloud environments. Check out this …

  • CentreCorp is a fully integrated and diversified property management and real estate service company, specializing in the "shopping center" segment, and is one of the premier retail service providers in North America. Company executives travel a great deal, carrying a number of traveling laptops with critical current business data, and no easy way to back up to the network outside the office. Read this case study to learn how CentreCorp implemented a suite of business continuity services that included …

Most Popular Programming Stories

More for Developers

RSS Feeds