{-# LANGUAGE CPP #-}
#if __GLASGOW_HASKELL__
{-# LANGUAGE MagicHash #-}
#endif
module Data.RangeMin.Common.Types (IP (..), LEq, RM, toRM, runRM, Index, Value, Length, RangeMin, PVector, VVector) where

import qualified Data.Vector.Primitive as P
import qualified Data.Vector as V

#if __GLASGOW_HASKELL__
import GHC.Exts (Int#, Int(..))
#endif

type PVector = P.Vector
type VVector = V.Vector

-- | The type of a vector index.
type Index = Int
-- | The type for which this package provides a specialized range-min implementation.
type Value = Int
-- | The type of the length of a vector.
type Length = Int
-- | A range min function.  Given an index @i@ and a length @m@, returns the 
-- minimum element in the range @i..i+m-1@.
type RangeMin = Index -> Length -> Index

-- | A function of type @'LEq' a@ is used as if it were @('<=')@ for comparison purposes.
-- This function /must/ be a total ordering.
type LEq a = a -> a -> Bool

data IP = IP {-# UNPACK #-} !Int {-# UNPACK #-} !Int

toRM :: (Index -> Length -> Index) -> RM
runRM :: RM -> Index -> Length -> Index

#if __GLASGOW_HASKELL__
type RM = (Int# -> Int# -> Int#)

{-# INLINE toRM #-}
toRM f = \ i# j# -> case f (I# i#) (I# j#) of
	I# k# -> k#

runRM f (I# i#) (I# j#) = I# (f i# j#)
#else
type RM = Index -> Index -> Index
toRM = id
runRM = id
#endif