Structured Data Exchange Format (SDXF)
RFC 3072

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Network Working Group                                       M. Wildgrube
Request for Comments: 3072                                    March 2001
Category: Informational

                 Structured Data Exchange Format (SDXF)

Status of this Memo

   This memo provides information for the Internet community.  It does
   not specify an Internet standard of any kind.  Distribution of this
   memo is unlimited.

Copyright Notice

   Copyright (C) The Internet Society (2001).  All Rights Reserved.

IESG Note

   This document specifies a data exchange format and, partially, an API
   that can be used for creating and parsing such a format.  The IESG
   notes that the same problem space can be addressed using formats that
   the IETF normally uses including ASN.1 and XML.  The document reader
   is strongly encouraged to carefully read section 13 before choosing
   SDXF over ASN.1 or XML.  Further, when storing text in SDXF, the user
   is encourage to use the datatype for UTF-8, specified in section 2.5.

Abstract

   This specification describes an all-purpose interchange format for
   use as a file format or for net-working.  Data is organized in chunks
   which can be ordered in hierarchical structures.  This format is
   self-describing and CPU-independent.

Table of Contents

   1.  Introduction ................................................. 2
   2.  Description of the SDXF data format .......................... 3
   3.  Introduction to the SDXF functions ........................... 5
   3.1 General remarks .............................................. 5
   3.2 Writing a SDXF buffer ........................................ 5
   3.3 Reading a SDXF buffer ........................................ 6
   3.4 Example ...................................................... 6
   4.  Platform independence ........................................ 8
   5.  Compression .................................................. 9
   6.  Encryption ...................................................11
   7.  Arrays........................................................11
   8.  Description of the SDXF functions ............................12

Wildgrube                    Informational                      [Page 1]
RFC 3072            Structured Data Exchange Format           March 2001

   8.1 Introduction .................................................12
   8.2 Basic definitions ............................................13
   8.3 Definitions for C++ ..........................................15
   8.4 Common Definitions ...........................................16
   8.5 Special functions ............................................17
   9.  'Support' of UTF-8 ...........................................19
   10.  Security Considerations .....................................19
   11.  Some general hints ..........................................20
   12.  IANA Considerations .........................................20
   13.  Discussion ..................................................21
   13.1 SDXF vs. ASN.1 ..............................................21
   13.2 SDXF vs. XML ................................................22
   14.  Author's Address ............................................24
   15.  Acknowledgements ............................................24
   16.  References ..................................................24
   17.  Full Copyright Statement ....................................26

1. Introduction

   The purpose of the Structured Data eXchange Format (SDXF) is to
   permit the interchange of an arbitrary structured data block with
   different kinds of data (numerical, text, bitstrings).  Because data
   is normalized to an abstract computer architecture independent
   "network format", SDXF is usable as a network interchange data
   format.

   This data format is not limited to any application, the demand for
   this format is that it is usable as a text format for word-
   processing, as a picture format, a sound format, for remote procedure
   calls with complex parameters, suitable for document formats, for
   interchanging business data, etc.

   SDXF is self-describing, every program can unpack every SDXF-data
   without knowing the meaning of the individual data elements.

   Together with the description of the data format a set of functions
   will be introduced.  With the help of these functions one can create
   and access the data elements of SDXF.  The idea is that a programmer
   should only use these functions instead of maintaining the structure
   by himself on the level of bits and bytes.  (In the speech of
   object-oriented programming these functions are methods of an object
   which works as a handle for a given SDXF data block.)

   SDXF is not limited to a specific platform, along with a correct
   preparation of the SDXF functions the SDXF data can be interchanged
   (via network or data carrier) across the boundaries of different
   architectures (specified by the character code like ASCII, ANSI or