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.ForeignPtr ( FinalizerPtr )
34 import Foreign.C.Types ( CSize )
35 import Foreign.Storable ( Storable(sizeOf) )
37 #ifdef __GLASGOW_HASKELL__
43 #elif defined(__NHC__)
46 import Control.Exception ( bracket )
53 -- |Allocate space for storable type. The size of the area allocated
54 -- is determined by the 'sizeOf' method from the instance of
55 -- 'Storable' for the appropriate type.
57 malloc :: Storable a => IO (Ptr a)
58 malloc = doMalloc undefined
60 doMalloc :: Storable a => a -> IO (Ptr a)
61 doMalloc dummy = mallocBytes (sizeOf dummy)
63 -- |Allocate given number of bytes of storage, equivalent to C\'s @malloc()@.
65 mallocBytes :: Int -> IO (Ptr a)
66 mallocBytes size = failWhenNULL "malloc" (_malloc (fromIntegral size))
68 -- |Temporarily allocate space for a storable type.
70 -- * the pointer passed as an argument to the function must /not/ escape from
71 -- this function; in other words, in @alloca f@ the allocated storage must
72 -- not be used after @f@ returns
74 alloca :: Storable a => (Ptr a -> IO b) -> IO b
75 alloca = doAlloca undefined
77 doAlloca :: Storable a => a -> (Ptr a -> IO b) -> IO b
78 doAlloca dummy = allocaBytes (sizeOf dummy)
80 -- |Temporarily allocate the given number of bytes of storage.
82 -- * the pointer passed as an argument to the function must /not/ escape from
83 -- this function; in other words, in @allocaBytes n f@ the allocated storage
84 -- must not be used after @f@ returns
86 #ifdef __GLASGOW_HASKELL__
87 allocaBytes :: Int -> (Ptr a -> IO b) -> IO b
88 allocaBytes (I# size) action = IO $ \ s ->
89 case newPinnedByteArray# size s of { (# s, mbarr# #) ->
90 case unsafeFreezeByteArray# mbarr# s of { (# s, barr# #) ->
91 let addr = Ptr (byteArrayContents# barr#) in
92 case action addr of { IO action ->
93 case action s of { (# s, r #) ->
94 case touch# barr# s of { s ->
98 allocaBytes :: Int -> (Ptr a -> IO b) -> IO b
99 allocaBytes size = bracket (mallocBytes size) free
102 -- |Adjust a malloc\'ed storage area to the given size of the required type
103 -- (corresponds to C\'s @realloc()@).
105 realloc :: Storable b => Ptr a -> IO (Ptr b)
106 realloc = doRealloc undefined
108 doRealloc :: Storable b => b -> Ptr a -> IO (Ptr b)
109 doRealloc dummy ptr = let
110 size = fromIntegral (sizeOf dummy)
112 failWhenNULL "realloc" (_realloc ptr size)
114 -- |Adjust a malloc\'ed storage area to the given size (equivalent to
115 -- C\'s @realloc()@).
117 reallocBytes :: Ptr a -> Int -> IO (Ptr a)
118 reallocBytes ptr size =
119 failWhenNULL "realloc" (_realloc ptr (fromIntegral size))
121 -- |Free malloc\'ed storage (equivalent to
124 free :: Ptr a -> IO ()
128 -- auxilliary routines
129 -- -------------------
131 -- asserts that the pointer returned from the action in the second argument is
134 failWhenNULL :: String -> IO (Ptr a) -> IO (Ptr a)
135 failWhenNULL name f = do
138 #ifdef __GLASGOW_HASKELL__
139 then ioException (IOError Nothing ResourceExhausted name
140 "out of memory" Nothing)
142 then ioError (userError (name++": out of memory"))
146 -- basic C routines needed for memory allocation
148 foreign import ccall unsafe "stdlib.h malloc" _malloc :: CSize -> IO (Ptr a)
149 foreign import ccall unsafe "stdlib.h realloc" _realloc :: Ptr a -> CSize -> IO (Ptr b)
150 foreign import ccall unsafe "stdlib.h free" _free :: Ptr a -> IO ()
152 -- | A pointer to a foreign function equivalent to 'free', which may be used
153 -- as a finalizer for storage allocated with 'malloc' or 'mallocBytes'.
154 foreign import ccall unsafe "stdlib.h &free" finalizerFree :: FinalizerPtr a