Saving a data structure to a file
Hi, I have a program which needs to cache intermediate data structures to a file (finite, non-cyclic, relatively simple, around ~100Kb when shown). Is there any easy way to acheive this? The current approach I am using is to add deriving Read, Show to all the data structures, and then writeFile "output.txt" (show x) read =<< readFile "output.txt" The problem is that this is too slow, and itsn't lazy. Is there any way to do better than this? I can imagine something like showBinary/readBinary which did this using binary files directly, but is there anything that does this? I'd like it to work with GHC and Hugs at least, and the less extra code I have to write the better :) Thanks Neil
Hello Neil, Friday, April 28, 2006, 7:59:22 PM, you wrote:
I have a program which needs to cache intermediate data structures to a file (finite, non-cyclic, relatively simple, around ~100Kb when shown). Is there any easy way to acheive this?
use NewBinary (darcs get http://www.n-heptane.com/nhlab/repos/NewBinary/) or jhc's Binary module together with DrIFT to generate Binary instances. these modules need minimal tweaks to implement Hugs compatibility code generated by DrIFT will use strict get. if you want to get lazy reading, you can replace get/put_ with lazyGet/lazyPut in appropriate instances in order to make it run faster, you should work with memory buffer and read/write entire buffer from/to file: writing: bh <- openBinMem 1 undefined lazyPut bh data ... put more data writeBinMem bh "filename" reading: bh <- readBinMem "filename" data <- lazyGet bh .... get more data -- Best regards, Bulat mailto:Bulat.Ziganshin@gmail.com
participants (2)
-
Bulat Ziganshin -
Neil Mitchell