simonmar:
On 18 October 2005 10:08, Krasimir Angelov wrote:
I am curious why FPS is implemented on top of ForeignPtr. ByteArray# based implementation should be faster and more space efficient.
Actually there's not much difference between ForeignPtr and ByteArray#, at least in GHC 6.5+ where we optimised the ForeignPtr implementation.
Furthermore ForeignPtr is much more useful, because you can create a ForeignPtr from a Ptr, and you can pass a ForeignPtr to C code portably (i.e. not using GHC extensions). ForeignPtr is essential if you want to make packed strings from eg. mmap()'d memory.
Right. And with a ForeignPtr, we can attach a finalizer, to e.g. unmap mmapped regions.
Also, a ForeignPtr allocated using mallocForeignPtr *is* a ByteArray#.
-- Don