Re: Read a fixed length of input each time

[Andrew J. Schorr]

On Tue, Jun 23, 2020 at 11:45:32AM -0500, Peng Yu wrote:
> For example, I may do the revert processing to get back the integers
> from the binary stream. For this kind of fixed binary stream, I feel
> the awk syntax would be better than writing a much longer Go file.
> 
> For example, if gawk would be able to split fields based on fixed
> field width and a fixed number of NF. Then, I may simply write awk
> code like the following (suppose that there is a bin2uint() function).
> It would be must shorter than the equivalent Go code to convert such
> binary stream to integers.
> 
> $ awk -e '{ for(i=1;i<=NF;++i) { print bin2unit($i) }'

To accomplish that, you'd need to write an extension library that allowed you
to specify the number of bytes in a record and the number of bytes in each
field. I'm not aware of any other way of achieving that, but it should be
pretty easy using the extension API.  And then you'd have to write the bin2uint
function, which I guess can be done using the ord() function in the ordchr
extension. But it still seems like this is probably much easier in other
languages such as Perl or Python (or perhaps Go; I'm less familiar with
that one). It's best to use the right tool for a given task; AWK is
designed for text manipulation, but other languages are better for
handling binary data.

Regards,
Andy