Tuesday, January 17, 2006

[Euphoria] Structured Access

Late last century, in a developing part of the world, I tried writing a diskette cataloguer. It worked okay, once I'd figured out how to do all the gymnastics necessary for BIOS calls. In the process I wrote a function to access memory in a structured way. Brilliant as Euphoria sequences are, they are just that: sequences. There's little in the way of structure, unless you apply some of your own.

I've reproduced the function in its entirety below. Essentially, the code takes data from memory in a structure way, that is, in terms of BYTE, BYTES, WORD, DWORD or ASCIIZ.

An attempt was made to make the functions applicable to files. Those routines don't work, and I haven't taken the time to find out why. Good as Euphoria is, there's no Mac OS X version (so I can't use it at home) and there's no opportunity to use it at work -- Euphoria's not in the SOE. If you're interested in looking at the code, write.
As an example of how to use getmen, below is the code for GetDriveParameterTable
As an example of the BYTES parameter:
The ASCIIZ parameter is like the BYTES except it keeps working its way through memory until it encounters a binary zero and then returns everything up to that point.

From memory I remember writing a version of getmem() which received a sequence of BYTE, WORD, etc. specifications and returned the resulting sequence of results. When I find it I'll post it.


No comments: