From: Michael Neumann <mneumann@...>
Date: 2005-07-06T17:48:00+09:00
Subject: Re: Reading arbitrary data into a c-like structure

Graham Nicholls wrote:
> I mentioned before that I'm writing a tool to extract data from a (dataease)
> database file according to a schema.   In 'C' I'd do something like
> 
> struct data 
> {
>         char header 4;
>         int recno;
>         char name[30];
>         char add_1[30];
>         ...
>         unsigned int cr_limit ;
> } data;
> 
> and if I set the compiler options right so the structure was closely packed,
> I could simply read the file into this structure, and print out the results
> using 

You need to read sizeof(data) bytes as a String, then unpack it.

Simple example:

   C:

   struct data {
     long a;
     long b;
   };

   Ruby:

   str = handle.read(8)
   a, b = str.unpack('LL')

Regards,

   Michael