1 -----------------------------------------------------------------------------
3 -- Module : Data.Array.Storable
4 -- Copyright : (c) The University of Glasgow 2001
5 -- License : BSD-style (see the file libraries/core/LICENSE)
7 -- Maintainer : libraries@haskell.org
8 -- Stability : experimental
9 -- Portability : non-portable
11 -- $Id: Storable.hs,v 1.2 2001/07/04 10:51:09 simonmar Exp $
13 -- A storable array is an IO-mutable array which stores its
14 -- contents in a contiguous memory block living in the C
15 -- heap. Elements are stored according to the class Storable.
16 -- You can obtain the pointer to the array contents to manipulate
17 -- elements from languages like C.
19 -- It's similar to IOUArray but slower. Its advantage is that
20 -- it's compatible with C.
22 -----------------------------------------------------------------------------
24 module Data.Array.Storable (
27 StorableArray, -- data StorableArray index element
28 -- -- index type must be in class Ix
29 -- -- element type must be in class Storable
31 -- Module MArray provides the interface of storable arrays.
32 -- They are instances of class MArray (with IO monad).
33 module Data.Array.MArray,
35 -- The pointer to the array contents is obtained by withStorableArray.
36 -- The idea is similar to ForeignPtr (used internally here). The
37 -- pointer should be used only during execution of the IO action
38 -- retured by the function passed as argument to withStorableArray:
39 withStorableArray, -- :: StorableArray i e -> (Ptr e -> IO a) -> IO a
41 -- If you want to use it afterwards, ensure that you
42 -- touchStorableArray after the last use of the pointer,
43 -- so the array is not freed too early:
44 touchStorableArray -- :: StorableArray i e -> IO ()
50 import Data.Array.Base
51 import Data.Array.MArray
52 import Foreign hiding (newArray)
54 data StorableArray i e = StorableArray !i !i !(ForeignPtr e)
56 instance HasBounds StorableArray where
57 bounds (StorableArray l u _) = (l,u)
59 instance Storable e => MArray StorableArray e IO where
61 newArray (l,u) init = do
63 sequence_ [pokeElemOff a i init | i <- [0..size-1]]
64 fp <- newForeignPtr a (free a)
65 return (StorableArray l u fp)
67 size = rangeSize (l,u)
70 a <- mallocArray (rangeSize (l,u))
71 fp <- newForeignPtr a (free a)
72 return (StorableArray l u fp)
74 unsafeRead (StorableArray _ _ fp) i =
75 withForeignPtr fp $ \a -> peekElemOff a i
77 unsafeWrite (StorableArray _ _ fp) i e =
78 withForeignPtr fp $ \a -> pokeElemOff a i e
80 withStorableArray :: StorableArray i e -> (Ptr e -> IO a) -> IO a
81 withStorableArray (StorableArray _ _ fp) f = withForeignPtr fp f
83 touchStorableArray :: StorableArray i e -> IO ()
84 touchStorableArray (StorableArray _ _ fp) = touchForeignPtr fp