{-# LANGUAGE Trustworthy #-} {-# LANGUAGE NoImplicitPrelude #-} -- ---------------------------------------------------------------------------- -- -- (c) The University of Glasgow 2006 -- -- Fingerprints for recompilation checking and ABI versioning, and -- implementing fast comparison of Typeable. -- -- ---------------------------------------------------------------------------- module GHC.Fingerprint.Type (Fingerprint(..)) where import GHC.Base import GHC.List (length, replicate) import GHC.Num import GHC.Show import GHC.Word import Numeric (showHex) -- Using 128-bit MD5 fingerprints for now. data Fingerprint = Fingerprint {-# UNPACK #-} !Word64 {-# UNPACK #-} !Word64 deriving ( Eq -- ^ @since 4.4.0.0 , Ord -- ^ @since 4.4.0.0 ) -- | @since 4.7.0.0 instance Show Fingerprint where show (Fingerprint w1 w2) = hex16 w1 ++ hex16 w2 where -- Formats a 64 bit number as 16 digits hex. hex16 :: Word64 -> String hex16 i = let hex = showHex i "" in replicate (16 - length hex) '0' ++ hex