On 8/27/12 5:33 PM, Donn Cave wrote:
It does, but it can also read directly to Ptr Word8 (fdReadBuf), which you'd think would be closer to hardware speed - but then you might lose the advantage trying to peek the data out of the buffer. In principle you ought to be able to stuff that pointer right into a ByteString, but don't know for sure that there's any public API for such.
As Austin Seipp mentioned, there's unix-bytestring[1] which minimizes the amount of marshaling/conversion imposed by using a high-level language. And it includes the obvious conversion between Ptr Word8 and ByteString. If there's any remaining overhead, let me know and I'll do my best to eliminate it. But, that's only for the reading and writing; opening files is another matter. If it's the *opening* of files that's causing the slowdown, then that has to be due to something in how GHC handles filename conversion et al. [1] http://hackage.haskell.org/package/unix-bytestring -- Live well, ~wren