zipWithM_ comes from Control.Monad
[packages/base.git] / Foreign / Marshal / Array.hs
1 {-# OPTIONS_GHC -XNoImplicitPrelude #-}
2 -----------------------------------------------------------------------------
3 -- |
4 -- Module : Foreign.Marshal.Array
5 -- Copyright : (c) The FFI task force 2001
6 -- License : BSD-style (see the file libraries/base/LICENSE)
7 --
8 -- Maintainer : ffi@haskell.org
9 -- Stability : provisional
10 -- Portability : portable
11 --
12 -- Marshalling support: routines allocating, storing, and retrieving Haskell
13 -- lists that are represented as arrays in the foreign language
14 --
15 -----------------------------------------------------------------------------
16
17 module Foreign.Marshal.Array (
18 -- * Marshalling arrays
19
20 -- ** Allocation
21 --
22 mallocArray, -- :: Storable a => Int -> IO (Ptr a)
23 mallocArray0, -- :: Storable a => Int -> IO (Ptr a)
24
25 allocaArray, -- :: Storable a => Int -> (Ptr a -> IO b) -> IO b
26 allocaArray0, -- :: Storable a => Int -> (Ptr a -> IO b) -> IO b
27
28 reallocArray, -- :: Storable a => Ptr a -> Int -> IO (Ptr a)
29 reallocArray0, -- :: Storable a => Ptr a -> Int -> IO (Ptr a)
30
31 -- ** Marshalling
32 --
33 peekArray, -- :: Storable a => Int -> Ptr a -> IO [a]
34 peekArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO [a]
35
36 pokeArray, -- :: Storable a => Ptr a -> [a] -> IO ()
37 pokeArray0, -- :: Storable a => a -> Ptr a -> [a] -> IO ()
38
39 -- ** Combined allocation and marshalling
40 --
41 newArray, -- :: Storable a => [a] -> IO (Ptr a)
42 newArray0, -- :: Storable a => a -> [a] -> IO (Ptr a)
43
44 withArray, -- :: Storable a => [a] -> (Ptr a -> IO b) -> IO b
45 withArray0, -- :: Storable a => a -> [a] -> (Ptr a -> IO b) -> IO b
46
47 withArrayLen, -- :: Storable a => [a] -> (Int -> Ptr a -> IO b) -> IO b
48 withArrayLen0, -- :: Storable a => a -> [a] -> (Int -> Ptr a -> IO b) -> IO b
49
50 -- ** Copying
51
52 -- | (argument order: destination, source)
53 copyArray, -- :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
54 moveArray, -- :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
55
56 -- ** Finding the length
57 --
58 lengthArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO Int
59
60 -- ** Indexing
61 --
62 advancePtr, -- :: Storable a => Ptr a -> Int -> Ptr a
63 ) where
64
65 import Foreign.Ptr (Ptr, plusPtr)
66 import Foreign.Storable (Storable(sizeOf,peekElemOff,pokeElemOff))
67 import Foreign.Marshal.Alloc (mallocBytes, allocaBytes, reallocBytes)
68 import Foreign.Marshal.Utils (copyBytes, moveBytes)
69
70 #ifdef __GLASGOW_HASKELL__
71 import GHC.IOBase
72 import GHC.Num
73 import GHC.List
74 import GHC.Err
75 import GHC.Base
76 #else
77 import Control.Monad (zipWithM_)
78 #endif
79
80 -- allocation
81 -- ----------
82
83 -- |Allocate storage for the given number of elements of a storable type
84 -- (like 'Foreign.Marshal.Alloc.malloc', but for multiple elements).
85 --
86 mallocArray :: Storable a => Int -> IO (Ptr a)
87 mallocArray = doMalloc undefined
88 where
89 doMalloc :: Storable a' => a' -> Int -> IO (Ptr a')
90 doMalloc dummy size = mallocBytes (size * sizeOf dummy)
91
92 -- |Like 'mallocArray', but add an extra position to hold a special
93 -- termination element.
94 --
95 mallocArray0 :: Storable a => Int -> IO (Ptr a)
96 mallocArray0 size = mallocArray (size + 1)
97
98 -- |Temporarily allocate space for the given number of elements
99 -- (like 'Foreign.Marshal.Alloc.alloca', but for multiple elements).
100 --
101 allocaArray :: Storable a => Int -> (Ptr a -> IO b) -> IO b
102 allocaArray = doAlloca undefined
103 where
104 doAlloca :: Storable a' => a' -> Int -> (Ptr a' -> IO b') -> IO b'
105 doAlloca dummy size = allocaBytes (size * sizeOf dummy)
106
107 -- |Like 'allocaArray', but add an extra position to hold a special
108 -- termination element.
109 --
110 allocaArray0 :: Storable a => Int -> (Ptr a -> IO b) -> IO b
111 allocaArray0 size = allocaArray (size + 1)
112
113 -- |Adjust the size of an array
114 --
115 reallocArray :: Storable a => Ptr a -> Int -> IO (Ptr a)
116 reallocArray = doRealloc undefined
117 where
118 doRealloc :: Storable a' => a' -> Ptr a' -> Int -> IO (Ptr a')
119 doRealloc dummy ptr size = reallocBytes ptr (size * sizeOf dummy)
120
121 -- |Adjust the size of an array including an extra position for the end marker.
122 --
123 reallocArray0 :: Storable a => Ptr a -> Int -> IO (Ptr a)
124 reallocArray0 ptr size = reallocArray ptr (size + 1)
125
126
127 -- marshalling
128 -- -----------
129
130 -- |Convert an array of given length into a Haskell list. This version
131 -- traverses the array backwards using an accumulating parameter,
132 -- which uses constant stack space. The previous version using mapM
133 -- needed linear stack space.
134 --
135 peekArray :: Storable a => Int -> Ptr a -> IO [a]
136 peekArray size ptr | size <= 0 = return []
137 | otherwise = f (size-1) []
138 where
139 f 0 acc = do e <- peekElemOff ptr 0; return (e:acc)
140 f n acc = do e <- peekElemOff ptr n; f (n-1) (e:acc)
141
142 -- |Convert an array terminated by the given end marker into a Haskell list
143 --
144 peekArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO [a]
145 peekArray0 marker ptr = do
146 size <- lengthArray0 marker ptr
147 peekArray size ptr
148
149 -- |Write the list elements consecutive into memory
150 --
151 pokeArray :: Storable a => Ptr a -> [a] -> IO ()
152 #ifndef __GLASGOW_HASKELL__
153 pokeArray ptr vals = zipWithM_ (pokeElemOff ptr) [0..] vals
154 #else
155 pokeArray ptr vals = go vals 0#
156 where go [] n# = return ()
157 go (val:vals) n# = do pokeElemOff ptr (I# n#) val; go vals (n# +# 1#)
158 #endif
159
160 -- |Write the list elements consecutive into memory and terminate them with the
161 -- given marker element
162 --
163 pokeArray0 :: Storable a => a -> Ptr a -> [a] -> IO ()
164 #ifndef __GLASGOW_HASKELL__
165 pokeArray0 marker ptr vals = do
166 pokeArray ptr vals
167 pokeElemOff ptr (length vals) marker
168 #else
169 pokeArray0 marker ptr vals = go vals 0#
170 where go [] n# = pokeElemOff ptr (I# n#) marker
171 go (val:vals) n# = do pokeElemOff ptr (I# n#) val; go vals (n# +# 1#)
172 #endif
173
174
175 -- combined allocation and marshalling
176 -- -----------------------------------
177
178 -- |Write a list of storable elements into a newly allocated, consecutive
179 -- sequence of storable values
180 -- (like 'Foreign.Marshal.Utils.new', but for multiple elements).
181 --
182 newArray :: Storable a => [a] -> IO (Ptr a)
183 newArray vals = do
184 ptr <- mallocArray (length vals)
185 pokeArray ptr vals
186 return ptr
187
188 -- |Write a list of storable elements into a newly allocated, consecutive
189 -- sequence of storable values, where the end is fixed by the given end marker
190 --
191 newArray0 :: Storable a => a -> [a] -> IO (Ptr a)
192 newArray0 marker vals = do
193 ptr <- mallocArray0 (length vals)
194 pokeArray0 marker ptr vals
195 return ptr
196
197 -- |Temporarily store a list of storable values in memory
198 -- (like 'Foreign.Marshal.Utils.with', but for multiple elements).
199 --
200 withArray :: Storable a => [a] -> (Ptr a -> IO b) -> IO b
201 withArray vals = withArrayLen vals . const
202
203 -- |Like 'withArray', but the action gets the number of values
204 -- as an additional parameter
205 --
206 withArrayLen :: Storable a => [a] -> (Int -> Ptr a -> IO b) -> IO b
207 withArrayLen vals f =
208 allocaArray len $ \ptr -> do
209 pokeArray ptr vals
210 res <- f len ptr
211 return res
212 where
213 len = length vals
214
215 -- |Like 'withArray', but a terminator indicates where the array ends
216 --
217 withArray0 :: Storable a => a -> [a] -> (Ptr a -> IO b) -> IO b
218 withArray0 marker vals = withArrayLen0 marker vals . const
219
220 -- |Like 'withArrayLen', but a terminator indicates where the array ends
221 --
222 withArrayLen0 :: Storable a => a -> [a] -> (Int -> Ptr a -> IO b) -> IO b
223 withArrayLen0 marker vals f =
224 allocaArray0 len $ \ptr -> do
225 pokeArray0 marker ptr vals
226 res <- f len ptr
227 return res
228 where
229 len = length vals
230
231
232 -- copying (argument order: destination, source)
233 -- -------
234
235 -- |Copy the given number of elements from the second array (source) into the
236 -- first array (destination); the copied areas may /not/ overlap
237 --
238 copyArray :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
239 copyArray = doCopy undefined
240 where
241 doCopy :: Storable a' => a' -> Ptr a' -> Ptr a' -> Int -> IO ()
242 doCopy dummy dest src size = copyBytes dest src (size * sizeOf dummy)
243
244 -- |Copy the given number of elements from the second array (source) into the
245 -- first array (destination); the copied areas /may/ overlap
246 --
247 moveArray :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
248 moveArray = doMove undefined
249 where
250 doMove :: Storable a' => a' -> Ptr a' -> Ptr a' -> Int -> IO ()
251 doMove dummy dest src size = moveBytes dest src (size * sizeOf dummy)
252
253
254 -- finding the length
255 -- ------------------
256
257 -- |Return the number of elements in an array, excluding the terminator
258 --
259 lengthArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO Int
260 lengthArray0 marker ptr = loop 0
261 where
262 loop i = do
263 val <- peekElemOff ptr i
264 if val == marker then return i else loop (i+1)
265
266
267 -- indexing
268 -- --------
269
270 -- |Advance a pointer into an array by the given number of elements
271 --
272 advancePtr :: Storable a => Ptr a -> Int -> Ptr a
273 advancePtr = doAdvance undefined
274 where
275 doAdvance :: Storable a' => a' -> Ptr a' -> Int -> Ptr a'
276 doAdvance dummy ptr i = ptr `plusPtr` (i * sizeOf dummy)