1 % -----------------------------------------------------------------------------
2 % $Id: PrelMarshalArray.lhs,v 1.10 2002/02/05 16:56:38 sewardj Exp $
4 % (c) The FFI task force, 2000
7 Marshalling support: routines allocating, storing, and retrieving Haskell
8 lists that are represented as arrays in the foreign language
11 {-# OPTIONS -fno-implicit-prelude #-}
13 module PrelMarshalArray (
17 mallocArray, -- :: Storable a => Int -> IO (Ptr a)
18 mallocArray0, -- :: Storable a => Int -> IO (Ptr a)
20 allocaArray, -- :: Storable a => Int -> (Ptr a -> IO b) -> IO b
21 allocaArray0, -- :: Storable a => Int -> (Ptr a -> IO b) -> IO b
23 reallocArray, -- :: Storable a => Ptr a -> Int -> IO (Ptr a)
24 reallocArray0, -- :: Storable a => Ptr a -> Int -> IO (Ptr a)
28 peekArray, -- :: Storable a => Int -> Ptr a -> IO [a]
29 peekArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO [a]
31 pokeArray, -- :: Storable a => Ptr a -> [a] -> IO ()
32 pokeArray0, -- :: Storable a => a -> Ptr a -> [a] -> IO ()
34 -- combined allocation and marshalling
36 newArray, -- :: Storable a => [a] -> IO (Ptr a)
37 newArray0, -- :: Storable a => a -> [a] -> IO (Ptr a)
39 withArray, -- :: Storable a => [a] -> (Ptr a -> IO b) -> IO b
40 withArray0, -- :: Storable a => a -> [a] -> (Ptr a -> IO b) -> IO b
42 -- copying (argument order: destination, source)
44 copyArray, -- :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
45 moveArray, -- :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
49 lengthArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO Int
53 advancePtr, -- :: Storable a => Ptr a -> Int -> Ptr a
55 -- DEPRECATED: Don't use!
56 destructArray, -- :: Storable a => Int -> Ptr a -> IO ()
57 destructArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO ()
62 #ifdef __GLASGOW_HASKELL__
63 import PrelPtr (Ptr, plusPtr)
64 import PrelStorable (Storable(sizeOf,peekElemOff,pokeElemOff,destruct))
65 import PrelMarshalAlloc (mallocBytes, allocaBytes, reallocBytes)
66 import PrelMarshalUtils (copyBytes, moveBytes)
77 -- allocate storage for the given number of elements of a storable type
79 mallocArray :: Storable a => Int -> IO (Ptr a)
80 mallocArray = doMalloc undefined
82 doMalloc :: Storable a => a -> Int -> IO (Ptr a)
83 doMalloc dummy size = mallocBytes (size * sizeOf dummy)
85 -- like `mallocArray', but add an extra element to signal the end of the array
87 mallocArray0 :: Storable a => Int -> IO (Ptr a)
88 mallocArray0 size = mallocArray (size + 1)
90 -- temporarily allocate space for the given number of elements
92 -- * see `MarshalAlloc.alloca' for the storage lifetime constraints
94 allocaArray :: Storable a => Int -> (Ptr a -> IO b) -> IO b
95 allocaArray = doAlloca undefined
97 doAlloca :: Storable a => a -> Int -> (Ptr a -> IO b) -> IO b
98 doAlloca dummy size = allocaBytes (size * sizeOf dummy)
100 -- like `allocaArray', but add an extra element to signal the end of the array
102 allocaArray0 :: Storable a => Int -> (Ptr a -> IO b) -> IO b
103 allocaArray0 size = allocaArray (size + 1)
105 -- adjust the size of an array
107 reallocArray :: Storable a => Ptr a -> Int -> IO (Ptr a)
108 reallocArray = doRealloc undefined
110 doRealloc :: Storable a => a -> Ptr a -> Int -> IO (Ptr a)
111 doRealloc dummy ptr size = reallocBytes ptr (size * sizeOf dummy)
113 -- adjust the size of an array while adding an element for the end marker
115 reallocArray0 :: Storable a => Ptr a -> Int -> IO (Ptr a)
116 reallocArray0 ptr size = reallocArray ptr (size + 1)
122 -- convert an array of given length into a Haskell list. This version
123 -- traverses the array backwards using an accumulating parameter,
124 -- which uses constant stack space. The previous version using mapM
125 -- needed linear stack space.
127 peekArray :: Storable a => Int -> Ptr a -> IO [a]
128 peekArray size ptr | size <= 0 = return []
129 | otherwise = f (size-1) []
131 f 0 acc = do e <- peekElemOff ptr 0; return (e:acc)
132 f n acc = do e <- peekElemOff ptr n; f (n-1) (e:acc)
134 -- convert an array terminated by the given end marker into a Haskell list
136 peekArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO [a]
137 peekArray0 marker ptr = loop 0
140 val <- peekElemOff ptr i
141 if val == marker then return [] else do
145 -- write the list elements consecutive into memory
147 pokeArray :: Storable a => Ptr a -> [a] -> IO ()
148 pokeArray ptr vals = zipWithM_ (pokeElemOff ptr) [0..] vals
150 -- write the list elements consecutive into memory and terminate them with the
151 -- given marker element
153 pokeArray0 :: Storable a => a -> Ptr a -> [a] -> IO ()
154 pokeArray0 marker ptr vals = do
156 pokeElemOff ptr (length vals) marker
159 -- combined allocation and marshalling
160 -- -----------------------------------
162 -- write a list of storable elements into a newly allocated, consecutive
163 -- sequence of storable values
165 newArray :: Storable a => [a] -> IO (Ptr a)
167 ptr <- mallocArray (length vals)
171 -- write a list of storable elements into a newly allocated, consecutive
172 -- sequence of storable values, where the end is fixed by the given end marker
174 newArray0 :: Storable a => a -> [a] -> IO (Ptr a)
175 newArray0 marker vals = do
176 ptr <- mallocArray0 (length vals)
177 pokeArray0 marker ptr vals
180 -- temporarily store a list of storable values in memory
182 withArray :: Storable a => [a] -> (Ptr a -> IO b) -> IO b
184 allocaArray len $ \ptr -> do
187 destructArray len ptr
192 -- like `withArray', but a terminator indicates where the array ends
194 withArray0 :: Storable a => a -> [a] -> (Ptr a -> IO b) -> IO b
195 withArray0 marker vals f =
196 allocaArray0 len $ \ptr -> do
197 pokeArray0 marker ptr vals
199 destructArray (len+1) ptr
208 -- destruct each element of an array (in reverse order)
210 destructArray :: Storable a => Int -> Ptr a -> IO ()
211 {-# DEPRECATED destructArray "This function is not standards compliant" #-}
212 destructArray size ptr =
213 sequence_ [destruct (ptr `advancePtr` i)
214 | i <- [size-1, size-2 .. 0]]
216 -- like `destructArray', but a terminator indicates where the array ends
218 destructArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO ()
219 {-# DEPRECATED destructArray0 "This function is not standards compliant" #-}
220 destructArray0 marker ptr = do
221 size <- lengthArray0 marker ptr
222 sequence_ [destruct (ptr `advancePtr` i)
223 | i <- [size, size-1 .. 0]]
226 -- copying (argument order: destination, source)
229 -- copy the given number of elements from the second array (source) into the
230 -- first array (destination); the copied areas may *not* overlap
232 copyArray :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
233 copyArray = doCopy undefined
235 doCopy :: Storable a => a -> Ptr a -> Ptr a -> Int -> IO ()
236 doCopy dummy dest src size = copyBytes dest src (size * sizeOf dummy)
238 -- copy the given number of elements from the second array (source) into the
239 -- first array (destination); the copied areas *may* overlap
241 moveArray :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
242 moveArray = doMove undefined
244 doMove :: Storable a => a -> Ptr a -> Ptr a -> Int -> IO ()
245 doMove dummy dest src size = moveBytes dest src (size * sizeOf dummy)
248 -- finding the length
249 -- ------------------
251 -- return the number of elements in an array, excluding the terminator
253 lengthArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO Int
254 lengthArray0 marker ptr = loop 0
257 val <- peekElemOff ptr i
258 if val == marker then return i else loop (i+1)
264 -- advance a pointer into an array by the given number of elements
266 advancePtr :: Storable a => Ptr a -> Int -> Ptr a
267 advancePtr = doAdvance undefined
269 doAdvance :: Storable a => a -> Ptr a -> Int -> Ptr a
270 doAdvance dummy ptr i = ptr `plusPtr` (i * sizeOf dummy)