Re: [Haskell-cafe] Help needed for converting IOArray to ByteString

On Tue, Feb 8, 2011 at 11:13 AM, C K Kashyap wrote:

On Tue, Feb 8, 2011 at 2:26 PM, Michael Snoyman wrote:

...

Your array contains machine-sized Ints, which in practice are likely either 32-bit or 64-bit, while a ByteString is the equivalent of an array or 8-bit values. So you'll need to somehow convert the Ints to Word8s. Do you know if you need big or little endian?

A basic approach would be:

* Use freeze to convert your IOArray into an IArray * Use putIArrayOf and put (from cereal) to generate a Putter value * Use runPut to generate a ByteString from that

Thanks Michael, Actually, I need an array of 8-bit words - Is that available? Also, would be hard to do it without cereal? Regards, Kashyap

1) Just use Data.Word.Word8 instead of the second Int in your type sig for IOArray 2) Use getElems to get a [Word8] 3) Data.ByteString.pack converts a [Word8] into a ByteString Michael