1 {-# OPTIONS -fno-implicit-prelude #-}
2 -----------------------------------------------------------------------------
4 -- Module : Foreign.Marshal.Array
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: routines allocating, storing, and retrieving Haskell
13 -- lists that are represented as arrays in the foreign language
15 -----------------------------------------------------------------------------
17 module Foreign.Marshal.Array (
18 -- * Marshalling arrays
22 mallocArray, -- :: Storable a => Int -> IO (Ptr a)
23 mallocArray0, -- :: Storable a => Int -> IO (Ptr a)
25 allocaArray, -- :: Storable a => Int -> (Ptr a -> IO b) -> IO b
26 allocaArray0, -- :: Storable a => Int -> (Ptr a -> IO b) -> IO b
28 reallocArray, -- :: Storable a => Ptr a -> Int -> IO (Ptr a)
29 reallocArray0, -- :: Storable a => Ptr a -> Int -> IO (Ptr a)
33 peekArray, -- :: Storable a => Int -> Ptr a -> IO [a]
34 peekArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO [a]
36 pokeArray, -- :: Storable a => Ptr a -> [a] -> IO ()
37 pokeArray0, -- :: Storable a => a -> Ptr a -> [a] -> IO ()
39 -- ** Combined allocation and marshalling
41 newArray, -- :: Storable a => [a] -> IO (Ptr a)
42 newArray0, -- :: Storable a => a -> [a] -> IO (Ptr a)
44 withArray, -- :: Storable a => [a] -> (Ptr a -> IO b) -> IO b
45 withArray0, -- :: Storable a => a -> [a] -> (Ptr a -> IO b) -> IO b
49 -- | (argument order: destination, source)
50 copyArray, -- :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
51 moveArray, -- :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
53 -- ** Finding the length
55 lengthArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO Int
59 advancePtr, -- :: Storable a => Ptr a -> Int -> Ptr a
63 import Foreign.Ptr (Ptr, plusPtr)
64 import Foreign.Storable (Storable(sizeOf,peekElemOff,pokeElemOff))
65 import Foreign.Marshal.Alloc (alloca, mallocBytes, allocaBytes, reallocBytes)
66 import Foreign.Marshal.Utils (copyBytes, moveBytes)
68 #ifdef __GLASGOW_HASKELL__
79 -- |Allocate storage for the given number of elements of a storable type.
81 mallocArray :: Storable a => Int -> IO (Ptr a)
82 mallocArray = doMalloc undefined
84 doMalloc :: Storable a => a -> Int -> IO (Ptr a)
85 doMalloc dummy size = mallocBytes (size * sizeOf dummy)
87 -- |Like 'mallocArray', but add an extra element to signal the end of the array
89 mallocArray0 :: Storable a => Int -> IO (Ptr a)
90 mallocArray0 size = mallocArray (size + 1)
92 -- |Temporarily allocate space for the given number of elements.
94 -- * see 'Foreign.Marshal.Alloc.alloca' for the storage lifetime constraints
96 allocaArray :: Storable a => Int -> (Ptr a -> IO b) -> IO b
97 allocaArray = doAlloca undefined
99 doAlloca :: Storable a => a -> Int -> (Ptr a -> IO b) -> IO b
100 doAlloca dummy size = allocaBytes (size * sizeOf dummy)
102 -- |Like 'allocaArray', but add an extra element to signal the end of the array
104 allocaArray0 :: Storable a => Int -> (Ptr a -> IO b) -> IO b
105 allocaArray0 size = allocaArray (size + 1)
107 -- |Adjust the size of an array
109 reallocArray :: Storable a => Ptr a -> Int -> IO (Ptr a)
110 reallocArray = doRealloc undefined
112 doRealloc :: Storable a => a -> Ptr a -> Int -> IO (Ptr a)
113 doRealloc dummy ptr size = reallocBytes ptr (size * sizeOf dummy)
115 -- |Adjust the size of an array while adding an element for the end marker
117 reallocArray0 :: Storable a => Ptr a -> Int -> IO (Ptr a)
118 reallocArray0 ptr size = reallocArray ptr (size + 1)
124 -- |Convert an array of given length into a Haskell list. This version
125 -- traverses the array backwards using an accumulating parameter,
126 -- which uses constant stack space. The previous version using mapM
127 -- needed linear stack space.
129 peekArray :: Storable a => Int -> Ptr a -> IO [a]
130 peekArray size ptr | size <= 0 = return []
131 | otherwise = f (size-1) []
133 f 0 acc = do e <- peekElemOff ptr 0; return (e:acc)
134 f n acc = do e <- peekElemOff ptr n; f (n-1) (e:acc)
136 -- |Convert an array terminated by the given end marker into a Haskell list
138 peekArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO [a]
139 peekArray0 marker ptr = loop 0
142 val <- peekElemOff ptr i
143 if val == marker then return [] else do
147 -- |Write the list elements consecutive into memory
149 pokeArray :: Storable a => Ptr a -> [a] -> IO ()
150 pokeArray ptr vals = zipWithM_ (pokeElemOff ptr) [0..] vals
152 -- |Write the list elements consecutive into memory and terminate them with the
153 -- given marker element
155 pokeArray0 :: Storable a => a -> Ptr a -> [a] -> IO ()
156 pokeArray0 marker ptr vals = do
158 pokeElemOff ptr (length vals) marker
161 -- combined allocation and marshalling
162 -- -----------------------------------
164 -- |Write a list of storable elements into a newly allocated, consecutive
165 -- sequence of storable values
167 newArray :: Storable a => [a] -> IO (Ptr a)
169 ptr <- mallocArray (length vals)
173 -- |Write a list of storable elements into a newly allocated, consecutive
174 -- sequence of storable values, where the end is fixed by the given end marker
176 newArray0 :: Storable a => a -> [a] -> IO (Ptr a)
177 newArray0 marker vals = do
178 ptr <- mallocArray0 (length vals)
179 pokeArray0 marker ptr vals
182 -- |Temporarily store a list of storable values in memory
184 withArray :: Storable a => [a] -> (Ptr a -> IO b) -> IO b
186 allocaArray len $ \ptr -> do
193 -- |Like 'withArray', but a terminator indicates where the array ends
195 withArray0 :: Storable a => a -> [a] -> (Ptr a -> IO b) -> IO b
196 withArray0 marker vals f =
197 allocaArray0 len $ \ptr -> do
198 pokeArray0 marker ptr vals
205 -- copying (argument order: destination, source)
208 -- |Copy the given number of elements from the second array (source) into the
209 -- first array (destination); the copied areas may /not/ overlap
211 copyArray :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
212 copyArray = doCopy undefined
214 doCopy :: Storable a => a -> Ptr a -> Ptr a -> Int -> IO ()
215 doCopy dummy dest src size = copyBytes dest src (size * sizeOf dummy)
217 -- |Copy the given number of elements from the second array (source) into the
218 -- first array (destination); the copied areas /may/ overlap
220 moveArray :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
221 moveArray = doMove undefined
223 doMove :: Storable a => a -> Ptr a -> Ptr a -> Int -> IO ()
224 doMove dummy dest src size = moveBytes dest src (size * sizeOf dummy)
227 -- finding the length
228 -- ------------------
230 -- |Return the number of elements in an array, excluding the terminator
232 lengthArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO Int
233 lengthArray0 marker ptr = loop 0
236 val <- peekElemOff ptr i
237 if val == marker then return i else loop (i+1)
243 -- |Advance a pointer into an array by the given number of elements
245 advancePtr :: Storable a => Ptr a -> Int -> Ptr a
246 advancePtr = doAdvance undefined
248 doAdvance :: Storable a => a -> Ptr a -> Int -> Ptr a
249 doAdvance dummy ptr i = ptr `plusPtr` (i * sizeOf dummy)