= Structured Binary Data =

[[PageOutline(2-3)]]

This page will document my thoughts and design ideas for the structured binary
data project. The project aims to address #317; a description of my overall
approach can be found on the
[https://www.google-melange.com/gsoc/project/google/gsoc2012/wtachi/46005 GSoC project page].

== Existing Tools ==

I am researching existing tools related to my project, so they can be used for inspiration.

=== [http://construct.wikispaces.com/ Construct] ===

TODO: looks promising. Also look at issues and forks.

=== [http://bindata.rubyforge.org/ BinData] ===

TODO: looks promising.

=== [http://wsgd.free.fr/ Wireshark Generic Dissector] ===

The length and real value of a field can depend on all previous fields and use
complex expressions. Structures can contain `if`/`while`/`continue`/`break`/…
statements.

=== Less interesting tools ===

 [https://www.wireshark.org/ Wireshark] and [http://www.tcpdump.org/ tcpdump]::
  As the Construct wiki notes, you would expect these developers to have some
  sort of DSL, but they just use C for everything. Wireshark does use ASN.1,
  Diameter, and MIDL for protocols developed with them.
 [http://kde.org/applications/utilities/okteta/ Okteta]::
  Has an XML format for simple structures, where the length of a field can
  depend on a previous value. Also has an on‐line database of structures, but
  it isn’t very popular—there are only nine submissions!
 Other simple formats::
  [http://ff-extractor.sourceforge.net/ ffe] can only handle trivial
  structures. [http://docs.python.org/library/struct.html Python’s struct]
  and [https://github.com/ToxicFrog/vstruct VStruct] use concise string formats
  to describe simple structures.
 Other hex editors::
  [http://beye.sourceforge.net/ Beye], [http://home.gna.org/bless/ Bless], and
  [https://live.gnome.org/Ghex GHex] lack interesting features.
 Protocol definition formats::
  [https://en.wikipedia.org/wiki/Abstract_Syntax_Notation_One ASN.1],
  [https://en.wikipedia.org/wiki/Microsoft_Interface_Definition_Language MIDL],
  and other IPC implementations go in the other direction: they generate a
  binary format from a text description of a structure. ASN.1 in particular
  has many features.