On Mon, 2 May 2011 17:50:48 -0400 (EDT) Dave Anderson <[email protected]> wrote:
> Sorry to bother you all, but I'm failing miserably at searching for a > tool to help analyze the structure of arbitrary files (prefereably one > which runs on OpenBSD). > > I've got a device which exports data in a undocumented format and the > only program available to use that data doesn't do what I need, so I > need to figure out the file formats so I can communicate with the device > the way I need to. > > What I'm looking for is an interactive program which makes it easy to > look at selected parts of a file (individual items, sets of items > located at regular intervals, sets of items linked by pointers or > offsets, etc) in any of many formats (ascii, unicode, int, double float, > etc) and either endianness, store comments about items or sets of items > in an aux file, store names for various values in particular items and > display those items values using those names, search for patterns at > regular intervals or linked by pointers or offsets, etc, etc, etc; all > those things which make it easier to discover and keep track of the > structure of an unknown file. > > It's hard to believe that nobody has ever written such a program, but > I've been unable to find one. Any suggestions for effective searches or > for suitable programs would be appreciated. > > Thanks, > > Dave > > -- > Dave Anderson > <[email protected]> > Never heard of such a program. I would use /usr/ports/editors/bvi, a hex editor, and Python, a very high-level scripting language in which you can perform various operations on data pretty easily. f = open('myfile.dat', 'rb') bytes = f.read(4) msg = 'first 4 bytes in hex: ' for x in bytes: msg += hex(ord(x))[2:].upper() print msg You could create a .py file with various useful functions, then start up Python interpreter, import this file and explore the file interactively by calling functions. Conceive a theory by trying to think how would you create a file for these purposes and by trying to see patterns in the file, test the theory by changing the file one thing at a time, observe behavior, repeat.
