-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | Type-checked pointer diffs
--   
--   Type-checked pointer diffs.
@package ptrdiff
@version 0


module Foreign.Ptr.Diff

-- | So long as <a>minusPtr</a> returns an <a>Int</a>, we're stuck with
--   size of <a>Int</a> = size of <tt>ptrdiff_t</tt>
newtype Diff a b
Diff :: Int -> Diff a b
[getDiff] :: Diff a b -> Int

-- | Invert a pointer <a>Diff</a>, e.g. convert a pointer to a field member
--   to one that computes the location of the parent, or one that computes
--   the offset of the next item into one that computes the offset of the
--   previous element.
inv :: Diff a b -> Diff b a

-- | Calculate the position of the next elment of a given type when they
--   are packed in densely.
next :: forall a. Storable a => Diff a a

-- | Calculate the position of the previous element of a given type when
--   they are packed in densely.
prev :: Storable a => Diff a a

-- | <a>Diff</a> is a groupoid, so <tt>Diff a a</tt> is a group, and as
--   such it forms a module over the integers
(.*) :: Int -> Diff a a -> Diff a a
infixr 6 .*

-- | Advance <tt>n</tt> (possibly negative) items in a dense packing.
advance :: Storable a => Int -> Diff a a
class DiffTorsor t
act :: DiffTorsor t => Diff a b -> t a -> t b
diff :: DiffTorsor t => t b -> t a -> Diff a b

-- | <a>peek</a> using a <a>Diff</a> between pointers to calculate the
--   offset.
peekDiffOff :: (MonadIO m, Storable b) => Ptr a -> Diff a b -> m b

-- | <a>poke</a> using a <a>Diff</a> between pointers to calculate the
--   offset.
pokeDiffOff :: (MonadIO m, Storable b) => Ptr a -> Diff a b -> b -> m ()
instance GHC.Generics.Generic (Foreign.Ptr.Diff.Diff a b)
instance (Data.Data.Data a, Data.Data.Data b) => Data.Data.Data (Foreign.Ptr.Diff.Diff a b)
instance GHC.Read.Read (Foreign.Ptr.Diff.Diff a b)
instance GHC.Show.Show (Foreign.Ptr.Diff.Diff a b)
instance GHC.Classes.Ord (Foreign.Ptr.Diff.Diff a b)
instance GHC.Classes.Eq (Foreign.Ptr.Diff.Diff a b)
instance Foreign.Ptr.Diff.DiffTorsor GHC.Ptr.Ptr
instance Foreign.Ptr.Diff.DiffTorsor GHC.Ptr.FunPtr
instance Foreign.Ptr.Diff.DiffTorsor GHC.ForeignPtr.ForeignPtr
instance Control.Category.Category Foreign.Ptr.Diff.Diff