Re: Embeddable Parser for binary data?

Wayne.Stidolph@mtv.gtegsc.com writes:
>I'm tasked to build a browser of binary data: the data (bus dumps) is
>to be shown to human users in meaningful forms.
...
>I propose the program read in the data block, read some headers in the
>data, and then decide which "format file" is appropriate. The program
>would then read in the "format file" and convert the data into strings
>for presentation. In essence, I need an interpreter where the "format
>file" is the program being interpreted, acting on the data block.


Many Prolog implementations have a DCG notation built in. (DCG = BNF +
arguments). You can write a useable parser/actioner in that, and Prolog
will let you assert (& retract) new grammar rules at run-time. It'll
probably be a tad sluggish mind ...


Alternatively use the parse command in Rexx (which comes with OS/2). This
can match patterns on a left-to-right basis, putting strings into
variables etc eg


          Block = '303132003334353600'x
          Format = "Prefix '00'x Body '00'x"
          interpret 'parse var Block' Format
          say 'P' Prefix 'B' Body /* gives P 012 B 3456 */


If you've structures like matching brackets you'll have to do something
fancy.


Use Watcom's VX-Rexx (aka VisualRexx) and you don't even have to touch C -
not sure whether VX-Rexx covers your graphics requirements but I think
there's a C API.


Yours, Patrick
--

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