Hi Simon, > We are all familiar with the idea of an MD5 checksum, which provides a > reliable "fingerprint" for a file, usually 128 bits or so. If the file > changes, the fingerprint is (almost) certain to do so too. There are lots of > techniques: CRC, shar?, MD5, etc.
I believe the basic operations are all in the Crypto library: http://hackage.haskell.org/cgi-bin/hackage-scripts/package/Crypto-3.0.3 - see Data.Digest.SHA1 and Data.Digest.MD5 - digest is simply another word for fingerprint in this sense. However, your fingerprint stuff sounds a lot more like a request for a Hash function - rather than something that operates over streams of bytes. To get both, I'd recommend something like taking the digest of the data after calling show, or after serialising it to a ByteString with the binary library. Doing it this way means you have no additional need for a FingerPrint class but can reuse the existing Show/Binary class. Thanks Neil _______________________________________________ Haskell mailing list Haskell@haskell.org http://www.haskell.org/mailman/listinfo/haskell
