Re: [Haskell-cafe] Re: Just for a laugh...

4 Jun 2007


      On 6/3/07, Rafael Almeida  wrote:
...
The site seems to be asking for the internal floating point
representation.  So it doesn't matter if it's IEEE 754, if the ints are
2-complements, or whatever. I used this code as a quick hack for one of
my programs, but I think it would work in this case. It should work for
any Storable type.
import qualified Data.ByteString as BS
import Data.ByteString.Base
import Foreign.ForeignPtr
import Foreign.Storable
binPut num =
    do
        fptr <- mallocForeignPtrBytes (sizeOf num)
        withForeignPtr (castForeignPtr fptr) (\x -> poke x num)
        BS.writeFile "/tmp/foo" (BS.reverse $ fromForeignPtr fptr (sizeOf num))
Ops, that reverse was needed for what I was doing, but not needed for
this particular problem, so the code should actually be:

import qualified Data.ByteString as BS
import Data.ByteString.Base
import Foreign.ForeignPtr
import Foreign.Storable
binPut num =
    do
        fptr <- mallocForeignPtrBytes (sizeOf num)
        withForeignPtr (castForeignPtr fptr) (\x -> poke x num)
        BS.writeFile "/tmp/foo" (fromForeignPtr fptr (sizeOf num))