1 {-# OPTIONS -fno-implicit-prelude #-}
2 -----------------------------------------------------------------------------
4 -- Module : Foreign.Marshal.Alloc
5 -- Copyright : (c) The FFI task force 2001
6 -- License : BSD-style (see the file libraries/base/LICENSE)
8 -- Maintainer : ffi@haskell.org
9 -- Stability : provisional
10 -- Portability : portable
12 -- Marshalling support: basic routines for memory allocation
14 -----------------------------------------------------------------------------
16 module Foreign.Marshal.Alloc (
18 malloc, -- :: Storable a => IO (Ptr a)
19 mallocBytes, -- :: Int -> IO (Ptr a)
21 alloca, -- :: Storable a => (Ptr a -> IO b) -> IO b
22 allocaBytes, -- :: Int -> (Ptr a -> IO b) -> IO b
24 realloc, -- :: Storable b => Ptr a -> IO (Ptr b)
25 reallocBytes, -- :: Ptr a -> Int -> IO (Ptr a)
27 free, -- :: Ptr a -> IO ()
28 finalizerFree -- :: FinalizerPtr a
32 import Foreign.Ptr ( Ptr, nullPtr, FunPtr )
33 import Foreign.C.Types ( CSize )
34 import Foreign.Storable ( Storable(sizeOf) )
36 #ifdef __GLASGOW_HASKELL__
37 import Foreign.ForeignPtr ( FinalizerPtr )
43 #elif defined(__NHC__)
44 import NHC.FFI ( FinalizerPtr, CInt(..) )
47 import Control.Exception ( bracket )
51 import Hugs.ForeignPtr ( FinalizerPtr )
58 -- |Allocate space for storable type. The size of the area allocated
59 -- is determined by the 'sizeOf' method from the instance of
60 -- 'Storable' for the appropriate type.
62 malloc :: Storable a => IO (Ptr a)
63 malloc = doMalloc undefined
65 doMalloc :: Storable a => a -> IO (Ptr a)
66 doMalloc dummy = mallocBytes (sizeOf dummy)
68 -- |Allocate given number of bytes of storage, equivalent to C\'s @malloc()@.
70 mallocBytes :: Int -> IO (Ptr a)
71 mallocBytes size = failWhenNULL "malloc" (_malloc (fromIntegral size))
73 -- |Temporarily allocate space for a storable type.
75 -- * the pointer passed as an argument to the function must /not/ escape from
76 -- this function; in other words, in @alloca f@ the allocated storage must
77 -- not be used after @f@ returns
79 alloca :: Storable a => (Ptr a -> IO b) -> IO b
80 alloca = doAlloca undefined
82 doAlloca :: Storable a => a -> (Ptr a -> IO b) -> IO b
83 doAlloca dummy = allocaBytes (sizeOf dummy)
85 -- |Temporarily allocate the given number of bytes of storage.
87 -- * the pointer passed as an argument to the function must /not/ escape from
88 -- this function; in other words, in @allocaBytes n f@ the allocated storage
89 -- must not be used after @f@ returns
91 #ifdef __GLASGOW_HASKELL__
92 allocaBytes :: Int -> (Ptr a -> IO b) -> IO b
93 allocaBytes (I# size) action = IO $ \ s ->
94 case newPinnedByteArray# size s of { (# s, mbarr# #) ->
95 case unsafeFreezeByteArray# mbarr# s of { (# s, barr# #) ->
96 let addr = Ptr (byteArrayContents# barr#) in
97 case action addr of { IO action ->
98 case action s of { (# s, r #) ->
99 case touch# barr# s of { s ->
103 allocaBytes :: Int -> (Ptr a -> IO b) -> IO b
104 allocaBytes size = bracket (mallocBytes size) free
107 -- |Adjust a malloc\'ed storage area to the given size of the required type
108 -- (corresponds to C\'s @realloc()@).
110 realloc :: Storable b => Ptr a -> IO (Ptr b)
111 realloc = doRealloc undefined
113 doRealloc :: Storable b => b -> Ptr a -> IO (Ptr b)
114 doRealloc dummy ptr = let
115 size = fromIntegral (sizeOf dummy)
117 failWhenNULL "realloc" (_realloc ptr size)
119 -- |Adjust a malloc\'ed storage area to the given size (equivalent to
120 -- C\'s @realloc()@).
122 reallocBytes :: Ptr a -> Int -> IO (Ptr a)
123 reallocBytes ptr size =
124 failWhenNULL "realloc" (_realloc ptr (fromIntegral size))
126 -- |Free malloc\'ed storage (equivalent to
129 free :: Ptr a -> IO ()
133 -- auxilliary routines
134 -- -------------------
136 -- asserts that the pointer returned from the action in the second argument is
139 failWhenNULL :: String -> IO (Ptr a) -> IO (Ptr a)
140 failWhenNULL name f = do
143 #ifdef __GLASGOW_HASKELL__
144 then ioException (IOError Nothing ResourceExhausted name
145 "out of memory" Nothing)
147 then ioError (userError (name++": out of memory"))
151 -- basic C routines needed for memory allocation
153 foreign import ccall unsafe "stdlib.h malloc" _malloc :: CSize -> IO (Ptr a)
154 foreign import ccall unsafe "stdlib.h realloc" _realloc :: Ptr a -> CSize -> IO (Ptr b)
155 foreign import ccall unsafe "stdlib.h free" _free :: Ptr a -> IO ()
157 -- | A pointer to a foreign function equivalent to 'free', which may be used
158 -- as a finalizer for storage allocated with 'malloc' or 'mallocBytes'.
159 foreign import ccall unsafe "stdlib.h &free" finalizerFree :: FinalizerPtr a