Free structure software for linux

GraphViz::Data::Structure can visualise data structures.

SYNOPSIS

use GraphViz::Data::Structure;

my $gvds = GraphViz:Data::Structure->new($data_structure);
print $gvds->graph()->as_png;

This module makes it easy to visualise data structures, even recursive or circular ones.
It is provided as an alternative to GraphViz::Data::Grapher. Differences:

GraphViz::Data::Structure handles structures of arbitrary depth and complexity, automatically following links using a standard graph traversal algorithm.
GraphViz::Data::Grapher creates graphics of indiividual substructures (arrays, scalars, hashes) which keep the substructure type and data together; GraphViz::Data::Structure does this by shape alone.
GraphViz::Data::Structure encapsulates object info (if any) directly into the node being used to represent the class.
GraphViz::Data::Grapher colors its graphs; GraphViz::Data::Structure doesnt by default.
GraphViz::Data:Structure can parse out globs and CODE references (almost as well as the debugger does).

Structured Document Validator project implements a generalized method for validating both the structure and content of structured documents.

Any data format that can be deterministically divided into tags and data is classed as a structured document. This definition applies to a wide array of data formats, including XML, Java properties files, and delimited value files.

The application performs validations based on user-defined Structured Document Definitions (SDDs). It provides an environment for validation, SDD development, and document editing.

Image::MetaData::JPEG::Structures is a Perl module that describes the structure of a JPEG file; it is an appendix to the main manual page of the Image::MetaData::JPEG module, which the reader should refer to for further details and the general scope.

THE STRUCTURE OF JPEG PICTURES

The JPEG (Joint Photographic Experts Group) ISO standard is a lossy image compression mechanism developed before 1990, designed for compressing colour or gray-scale photo-realistic images (it performs poorly on line-art drawings). The JPEG mechanism is designed to exploit known limitations of the human eye, in particular the fact that colour changes are perceived less accurately than changes in brightness.

Note that although the "baseline" JPEG format is patent-free, there are patents associated with some optional features, namely arithmetic coding and hierarchical storage. For this reason, these optional features are never used on the Web (good job, patent fans ...). JPEG refers only to a class of compression algorithms, not to a specific file format. In order to produce files with embedded JPEG streams, a number of file format (semi-)standards have been adapted or devised, some of which are listed in the format section. The structure of a well formed JPEG file can be described by the following pseudo production rules (for sake of simplicity, some additional constraints between tables and SOF segments are neglected).

JPEG --> (SOI)(misc)*(image)?(EOI)
(image) --> (hierarch.)|(non-hier.)
(hierarch.) --> (DHP)(frame)+
(frame) --> (misc)*(EXP)?(non-hier.)
(non-hier.) --> (SOF)(scan)+
(scan) --> (misc)*(SOS)(data)*(ECS)(DNL)?
(data) --> (ECS)(RST)
(misc) --> (DQT)|(DHT)|(DAC)|(DRI)|(COM)|(APP)

(SOI) = Start Of Image
(EOI) = End Of Image
(SOF) = Start Of Frame header (10 types)
(SOS) = Start Of Scan header
(ECS) = Entropy Coded Segment (row data, not a real segment)
(DNL) = Define Number of Lines segment
(DHP) = Define Hierarchical P??? segment
(EXP) = EXPansion segment
(RST) = ReSTart segment (8 types)
(DQT) = Define Quantisation Table
(DHT) = Define Huffman coding Table
(DAC) = Define Arithmetic coding Table
(DRI) = Define Restart Interval
(COM) = COMment segment
(APP) = APPlication segment

This package does not check that a JPEG file is really correct; it accepts a looser syntax, were segments and ECS blocks are just contiguous (basically, because it does not need to display the image!). All meta-data information is concentrated in the (COM*) and (APP) Segments, exception made for some records in the (SOF*) segment (e.g. image dimensions).

Reference: B< "Digital compression and coding of continuous-tone still
images: requirements and guidelines", CCITT recommend. T.81, 1992,
The International Telegraph and Telephone Consultative Committee,
standard ISO/IEC IS 10918-1 or ITU-T Recommendation T.81 >.
Also: B< "The JPEG still picture compression standard", G.K.Wallace,
1991, IEEE Transactions on Consumer Electronics >.

Memory Structures Library (MemSL) is a complete data structures/collection classes library with memory tracing, memory debugging, entry/exit tracing, exception handling, definable memory handlers, built-in thread support, and much more.

The project supports single, double, and circular linked lists, AVL balanced and threaded binary trees, dynamic hashing tables, stacks, queues and dequeues (using arrays or linked lists), sets (Pascal implementation, with union, difference, intersection, etc.), bags, tables and dictionaries, priority heaps, priority search queue, and more.

GNOME Structured File Library is a utility library for reading and writing structured file formats. Support for MS OLE2 streams is complete, as is zip import.
There is also support for document metadata and some initial work on decompressing VBA streams in OLE files for future conversion to other languages.
This library replaces libole2 and is used in gnumeric, mrproject, abiword, libwv2, koffice. It is also part of the AAF format.
Enhancements:
- This release reverts jump to dynamic types, as they arent thread-safe.
- A compilation glitch on Windows has been fixed.
- Problems building without gconf macros installed are avoided.
- Configure breakage with --without-gnome has been fixed.

videocheck project is a simple program for checking and analyzing video AVI file structure.

The program is useful for recovering broken AVI files or finding bugs during development of software that produces AVI files.

M3U-Playlist Manager is an administration of loose m3u-playlists in tree structure. Simple mouse-click to add or remove a song from playlist with currently running Song in the Player.

And other interesting functions. Supporting only XMMS at the moment.