[Haskell-cafe] binary IO

[Joel Reymont]

This is what I spent the past 3 months on. Pickling code that  
interoperates with a C++ server that sends things to me little- 
endian. And sends other wierd data like unicode strings that are zero- 
terminated.

SerTH does not handle things like that since it cannot divine the  
wire format for you. I used the pickler combinators approach which  
worked great in theory since I could specify the wire format and have  
a single spec for pickling and unpickling. In practice this turned  
out to be too slow and I still don't know why.

I'm still waiting to see how this should really be done.

	Joel

On Dec 27, 2005, at 7:35 AM, Jeremy Shaw wrote:

> There is one important difference in my mind. Most of the pickling  
> code
> is concerned with turning haskell data into a binary stream that can
> later be turned back into haskell data. There is no interoperability
> required -- the thing that writes it is the thing that will read it.
>
> For parsing arbitrary binary data formats a few other important
> issues arise that you can sometimes forget about with pickling such
> as:
>
>  ~ byte-alignment
>  ~ big-endian vs little endian
>  ~ size of data types (for example is Char one byte or four)
>  ~ bitwise parsing
>
> Both pickling and binary format parsing can be built on the same
> underlying low-level binary access methods.

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