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 -- :: FunPtr (Ptr a -> IO ())
32 import Foreign.Ptr ( Ptr, nullPtr, FunPtr )
33 import Foreign.C.Types ( CSize )
34 import Foreign.Storable ( Storable(sizeOf) )
36 #ifdef __GLASGOW_HASKELL__
42 #elif defined(__NHC__)
45 import Control.Exception ( bracket )
52 -- |Allocate space for storable type. The size of the area allocated
53 -- is determined by the 'sizeOf' method from the instance of
54 -- 'Storable' for the appropriate type.
56 malloc :: Storable a => IO (Ptr a)
57 malloc = doMalloc undefined
59 doMalloc :: Storable a => a -> IO (Ptr a)
60 doMalloc dummy = mallocBytes (sizeOf dummy)
62 -- |Allocate given number of bytes of storage, equivalent to C\'s @malloc()@.
64 mallocBytes :: Int -> IO (Ptr a)
65 mallocBytes size = failWhenNULL "malloc" (_malloc (fromIntegral size))
67 -- |Temporarily allocate space for a storable type.
69 -- * the pointer passed as an argument to the function must /not/ escape from
70 -- this function; in other words, in @alloca f@ the allocated storage must
71 -- not be used after @f@ returns
73 alloca :: Storable a => (Ptr a -> IO b) -> IO b
74 alloca = doAlloca undefined
76 doAlloca :: Storable a => a -> (Ptr a -> IO b) -> IO b
77 doAlloca dummy = allocaBytes (sizeOf dummy)
79 -- |Temporarily allocate the given number of bytes of storage.
81 -- * the pointer passed as an argument to the function must /not/ escape from
82 -- this function; in other words, in @allocaBytes n f@ the allocated storage
83 -- must not be used after @f@ returns
85 #ifdef __GLASGOW_HASKELL__
86 allocaBytes :: Int -> (Ptr a -> IO b) -> IO b
87 allocaBytes (I# size) action = IO $ \ s ->
88 case newPinnedByteArray# size s of { (# s, mbarr# #) ->
89 case unsafeFreezeByteArray# mbarr# s of { (# s, barr# #) ->
90 let addr = Ptr (byteArrayContents# barr#) in
91 case action addr of { IO action ->
92 case action s of { (# s, r #) ->
93 case touch# barr# s of { s ->
97 allocaBytes :: Int -> (Ptr a -> IO b) -> IO b
98 allocaBytes size = bracket (mallocBytes size) free
101 -- |Adjust a malloc\'ed storage area to the given size of the required type
102 -- (corresponds to C\'s @realloc()@).
104 realloc :: Storable b => Ptr a -> IO (Ptr b)
105 realloc = doRealloc undefined
107 doRealloc :: Storable b => b -> Ptr a -> IO (Ptr b)
108 doRealloc dummy ptr = let
109 size = fromIntegral (sizeOf dummy)
111 failWhenNULL "realloc" (_realloc ptr size)
113 -- |Adjust a malloc\'ed storage area to the given size (equivalent to
114 -- C\'s @realloc()@).
116 reallocBytes :: Ptr a -> Int -> IO (Ptr a)
117 reallocBytes ptr size =
118 failWhenNULL "realloc" (_realloc ptr (fromIntegral size))
120 -- |Free malloc\'ed storage (equivalent to
123 free :: Ptr a -> IO ()
127 -- auxilliary routines
128 -- -------------------
130 -- asserts that the pointer returned from the action in the second argument is
133 failWhenNULL :: String -> IO (Ptr a) -> IO (Ptr a)
134 failWhenNULL name f = do
137 #ifdef __GLASGOW_HASKELL__
138 then ioException (IOError Nothing ResourceExhausted name
139 "out of memory" Nothing)
141 then ioError (userError (name++": out of memory"))
145 -- basic C routines needed for memory allocation
147 foreign import ccall unsafe "stdlib.h malloc" _malloc :: CSize -> IO (Ptr a)
148 foreign import ccall unsafe "stdlib.h realloc" _realloc :: Ptr a -> CSize -> IO (Ptr b)
149 foreign import ccall unsafe "stdlib.h free" _free :: Ptr a -> IO ()
151 -- | A pointer to a foreign function equivalent to 'free', which may be used
152 -- as a finalizer for storage allocated with 'malloc' or 'mallocBytes'.
153 foreign import ccall unsafe "stdlib.h &free"
154 finalizerFree :: FunPtr (Ptr a -> IO ())