{-# OPTIONS -fno-implicit-prelude #-}
-----------------------------------------------------------------------------
---
+-- |
-- Module : Foreign.Marshal.Array
-- Copyright : (c) The FFI task force 2001
--- License : BSD-style (see the file libraries/core/LICENSE)
+-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : ffi@haskell.org
--- Stability : experimental
--- Portability : non-portable
---
--- $Id: Array.hs,v 1.1 2001/06/28 14:15:03 simonmar Exp $
+-- Stability : provisional
+-- Portability : portable
--
-- Marshalling support: routines allocating, storing, and retrieving Haskell
-- lists that are represented as arrays in the foreign language
-----------------------------------------------------------------------------
module Foreign.Marshal.Array (
+ -- * Marshalling arrays
- -- allocation
+ -- ** Allocation
--
mallocArray, -- :: Storable a => Int -> IO (Ptr a)
mallocArray0, -- :: Storable a => Int -> IO (Ptr a)
reallocArray, -- :: Storable a => Ptr a -> Int -> IO (Ptr a)
reallocArray0, -- :: Storable a => Ptr a -> Int -> IO (Ptr a)
- -- marshalling
+ -- ** Marshalling
--
peekArray, -- :: Storable a => Int -> Ptr a -> IO [a]
peekArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO [a]
pokeArray, -- :: Storable a => Ptr a -> [a] -> IO ()
pokeArray0, -- :: Storable a => a -> Ptr a -> [a] -> IO ()
- -- combined allocation and marshalling
+ -- ** Combined allocation and marshalling
--
newArray, -- :: Storable a => [a] -> IO (Ptr a)
newArray0, -- :: Storable a => a -> [a] -> IO (Ptr a)
withArray, -- :: Storable a => [a] -> (Ptr a -> IO b) -> IO b
withArray0, -- :: Storable a => a -> [a] -> (Ptr a -> IO b) -> IO b
- -- destruction
- --
- destructArray, -- :: Storable a => Int -> Ptr a -> IO ()
- destructArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO ()
+ -- ** Copying
- -- copying (argument order: destination, source)
- --
+ -- | (argument order: destination, source)
copyArray, -- :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
moveArray, -- :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
- -- finding the length
+ -- ** Finding the length
--
lengthArray0, -- :: (Storable a, Eq a) => a -> Ptr a -> IO Int
- -- indexing
+ -- ** Indexing
--
- advancePtr -- :: Storable a => Ptr a -> Int -> Ptr a
+ advancePtr, -- :: Storable a => Ptr a -> Int -> Ptr a
) where
import Control.Monad
#ifdef __GLASGOW_HASKELL__
import Foreign.Ptr (Ptr, plusPtr)
-import GHC.Storable (Storable(sizeOf,peekElemOff,pokeElemOff,destruct))
-import Foreign.Marshal.Alloc (mallocBytes, allocaBytes, reallocBytes)
+import GHC.Storable (Storable(sizeOf,peekElemOff,pokeElemOff))
+import Foreign.Marshal.Alloc (alloca, mallocBytes, allocaBytes, reallocBytes)
import Foreign.Marshal.Utils (copyBytes, moveBytes)
import GHC.IOBase
import GHC.Num
-- allocation
-- ----------
--- allocate storage for the given number of elements of a storable type
+-- |Allocate storage for the given number of elements of a storable type.
--
mallocArray :: Storable a => Int -> IO (Ptr a)
mallocArray = doMalloc undefined
doMalloc :: Storable a => a -> Int -> IO (Ptr a)
doMalloc dummy size = mallocBytes (size * sizeOf dummy)
--- like `mallocArray', but add an extra element to signal the end of the array
+-- |Like 'mallocArray', but add an extra element to signal the end of the array
--
mallocArray0 :: Storable a => Int -> IO (Ptr a)
mallocArray0 size = mallocArray (size + 1)
--- temporarily allocate space for the given number of elements
+-- |Temporarily allocate space for the given number of elements.
--
--- * see `MarshalAlloc.alloca' for the storage lifetime constraints
+-- * see 'Foreign.Marshal.Alloc.alloca' for the storage lifetime constraints
--
allocaArray :: Storable a => Int -> (Ptr a -> IO b) -> IO b
allocaArray = doAlloca undefined
doAlloca :: Storable a => a -> Int -> (Ptr a -> IO b) -> IO b
doAlloca dummy size = allocaBytes (size * sizeOf dummy)
--- like `allocaArray', but add an extra element to signal the end of the array
+-- |Like 'allocaArray', but add an extra element to signal the end of the array
--
allocaArray0 :: Storable a => Int -> (Ptr a -> IO b) -> IO b
allocaArray0 size = allocaArray (size + 1)
--- adjust the size of an array
+-- |Adjust the size of an array
--
reallocArray :: Storable a => Ptr a -> Int -> IO (Ptr a)
reallocArray = doRealloc undefined
doRealloc :: Storable a => a -> Ptr a -> Int -> IO (Ptr a)
doRealloc dummy ptr size = reallocBytes ptr (size * sizeOf dummy)
--- adjust the size of an array while adding an element for the end marker
+-- |Adjust the size of an array while adding an element for the end marker
--
reallocArray0 :: Storable a => Ptr a -> Int -> IO (Ptr a)
reallocArray0 ptr size = reallocArray ptr (size + 1)
-- marshalling
-- -----------
--- convert an array of given length into a Haskell list
+-- |Convert an array of given length into a Haskell list. This version
+-- traverses the array backwards using an accumulating parameter,
+-- which uses constant stack space. The previous version using mapM
+-- needed linear stack space.
--
peekArray :: Storable a => Int -> Ptr a -> IO [a]
-peekArray size ptr = mapM (peekElemOff ptr) [0..size-1]
-
--- convert an array terminated by the given end marker into a Haskell list
+peekArray size ptr | size <= 0 = return []
+ | otherwise = f (size-1) []
+ where
+ f 0 acc = do e <- peekElemOff ptr 0; return (e:acc)
+ f n acc = do e <- peekElemOff ptr n; f (n-1) (e:acc)
+
+-- |Convert an array terminated by the given end marker into a Haskell list
--
peekArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO [a]
peekArray0 marker ptr = loop 0
rest <- loop (i+1)
return (val:rest)
--- write the list elements consecutive into memory
+-- |Write the list elements consecutive into memory
--
pokeArray :: Storable a => Ptr a -> [a] -> IO ()
pokeArray ptr vals = zipWithM_ (pokeElemOff ptr) [0..] vals
--- write the list elements consecutive into memory and terminate them with the
+-- |Write the list elements consecutive into memory and terminate them with the
-- given marker element
--
pokeArray0 :: Storable a => a -> Ptr a -> [a] -> IO ()
-- combined allocation and marshalling
-- -----------------------------------
--- write a list of storable elements into a newly allocated, consecutive
+-- |Write a list of storable elements into a newly allocated, consecutive
-- sequence of storable values
--
newArray :: Storable a => [a] -> IO (Ptr a)
pokeArray ptr vals
return ptr
--- write a list of storable elements into a newly allocated, consecutive
+-- |Write a list of storable elements into a newly allocated, consecutive
-- sequence of storable values, where the end is fixed by the given end marker
--
newArray0 :: Storable a => a -> [a] -> IO (Ptr a)
pokeArray0 marker ptr vals
return ptr
--- temporarily store a list of storable values in memory
+-- |Temporarily store a list of storable values in memory
--
withArray :: Storable a => [a] -> (Ptr a -> IO b) -> IO b
withArray vals f =
allocaArray len $ \ptr -> do
pokeArray ptr vals
res <- f ptr
- destructArray len ptr
return res
where
len = length vals
--- like `withArray', but a terminator indicates where the array ends
+-- |Like 'withArray', but a terminator indicates where the array ends
--
withArray0 :: Storable a => a -> [a] -> (Ptr a -> IO b) -> IO b
withArray0 marker vals f =
allocaArray0 len $ \ptr -> do
pokeArray0 marker ptr vals
res <- f ptr
- destructArray (len+1) ptr
return res
where
len = length vals
--- destruction
--- -----------
-
--- destruct each element of an array (in reverse order)
---
-destructArray :: Storable a => Int -> Ptr a -> IO ()
-destructArray size ptr =
- sequence_ [destruct (ptr `advancePtr` i)
- | i <- [size-1, size-2 .. 0]]
-
--- like `destructArray', but a terminator indicates where the array ends
---
-destructArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO ()
-destructArray0 marker ptr = do
- size <- lengthArray0 marker ptr
- sequence_ [destruct (ptr `advancePtr` i)
- | i <- [size, size-1 .. 0]]
-
-
-- copying (argument order: destination, source)
-- -------
--- copy the given number of elements from the second array (source) into the
--- first array (destination); the copied areas may *not* overlap
+-- |Copy the given number of elements from the second array (source) into the
+-- first array (destination); the copied areas may /not/ overlap
--
copyArray :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
copyArray = doCopy undefined
doCopy :: Storable a => a -> Ptr a -> Ptr a -> Int -> IO ()
doCopy dummy dest src size = copyBytes dest src (size * sizeOf dummy)
--- copy the given number of elements from the second array (source) into the
--- first array (destination); the copied areas *may* overlap
+-- |Copy the given number of elements from the second array (source) into the
+-- first array (destination); the copied areas /may/ overlap
--
moveArray :: Storable a => Ptr a -> Ptr a -> Int -> IO ()
moveArray = doMove undefined
-- finding the length
-- ------------------
--- return the number of elements in an array, excluding the terminator
+-- |Return the number of elements in an array, excluding the terminator
--
lengthArray0 :: (Storable a, Eq a) => a -> Ptr a -> IO Int
lengthArray0 marker ptr = loop 0
-- indexing
-- --------
--- advance a pointer into an array by the given number of elements
+-- |Advance a pointer into an array by the given number of elements
--
advancePtr :: Storable a => Ptr a -> Int -> Ptr a
advancePtr = doAdvance undefined
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