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__)
46 import Control.Exception ( bracket )
50 import Hugs.ForeignPtr ( FinalizerPtr )
56 -- |Allocate space for storable type. The size of the area allocated
57 -- is determined by the 'sizeOf' method from the instance of
58 -- 'Storable' for the appropriate type.
60 malloc :: Storable a => IO (Ptr a)
61 malloc = doMalloc undefined
63 doMalloc :: Storable a => a -> IO (Ptr a)
64 doMalloc dummy = mallocBytes (sizeOf dummy)
66 -- |Allocate given number of bytes of storage, equivalent to C\'s @malloc()@.
68 mallocBytes :: Int -> IO (Ptr a)
69 mallocBytes size = failWhenNULL "malloc" (_malloc (fromIntegral size))
71 -- |Temporarily allocate space for a storable type.
73 -- * the pointer passed as an argument to the function must /not/ escape from
74 -- this function; in other words, in @alloca f@ the allocated storage must
75 -- not be used after @f@ returns
77 alloca :: Storable a => (Ptr a -> IO b) -> IO b
78 alloca = doAlloca undefined
80 doAlloca :: Storable a => a -> (Ptr a -> IO b) -> IO b
81 doAlloca dummy = allocaBytes (sizeOf dummy)
83 -- |Temporarily allocate the given number of bytes of storage.
85 -- * the pointer passed as an argument to the function must /not/ escape from
86 -- this function; in other words, in @allocaBytes n f@ the allocated storage
87 -- must not be used after @f@ returns
89 #ifdef __GLASGOW_HASKELL__
90 allocaBytes :: Int -> (Ptr a -> IO b) -> IO b
91 allocaBytes (I# size) action = IO $ \ s ->
92 case newPinnedByteArray# size s of { (# s, mbarr# #) ->
93 case unsafeFreezeByteArray# mbarr# s of { (# s, barr# #) ->
94 let addr = Ptr (byteArrayContents# barr#) in
95 case action addr of { IO action ->
96 case action s of { (# s, r #) ->
97 case touch# barr# s of { s ->
101 allocaBytes :: Int -> (Ptr a -> IO b) -> IO b
102 allocaBytes size = bracket (mallocBytes size) free
105 -- |Adjust a malloc\'ed storage area to the given size of the required type
106 -- (corresponds to C\'s @realloc()@).
108 realloc :: Storable b => Ptr a -> IO (Ptr b)
109 realloc = doRealloc undefined
111 doRealloc :: Storable b => b -> Ptr a -> IO (Ptr b)
112 doRealloc dummy ptr = let
113 size = fromIntegral (sizeOf dummy)
115 failWhenNULL "realloc" (_realloc ptr size)
117 -- |Adjust a malloc\'ed storage area to the given size (equivalent to
118 -- C\'s @realloc()@).
120 reallocBytes :: Ptr a -> Int -> IO (Ptr a)
121 reallocBytes ptr size =
122 failWhenNULL "realloc" (_realloc ptr (fromIntegral size))
124 -- |Free malloc\'ed storage (equivalent to
127 free :: Ptr a -> IO ()
131 -- auxilliary routines
132 -- -------------------
134 -- asserts that the pointer returned from the action in the second argument is
137 failWhenNULL :: String -> IO (Ptr a) -> IO (Ptr a)
138 failWhenNULL name f = do
141 #ifdef __GLASGOW_HASKELL__
142 then ioException (IOError Nothing ResourceExhausted name
143 "out of memory" Nothing)
145 then ioError (userError (name++": out of memory"))
149 -- basic C routines needed for memory allocation
151 foreign import ccall unsafe "stdlib.h malloc" _malloc :: CSize -> IO (Ptr a)
152 foreign import ccall unsafe "stdlib.h realloc" _realloc :: Ptr a -> CSize -> IO (Ptr b)
153 foreign import ccall unsafe "stdlib.h free" _free :: Ptr a -> IO ()
155 -- | A pointer to a foreign function equivalent to 'free', which may be used
156 -- as a finalizer for storage allocated with 'malloc' or 'mallocBytes'.
157 foreign import ccall unsafe "stdlib.h &free" finalizerFree :: FinalizerPtr a