/usr/lib/hugs/packages/base/Foreign/Marshal/Utils.hs is in libhugs-base-bundled 98.200609.21-5.4.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 | {-# OPTIONS_GHC -fno-implicit-prelude #-}
-----------------------------------------------------------------------------
-- |
-- Module : Foreign.Marshal.Utils
-- Copyright : (c) The FFI task force 2001
-- License : BSD-style (see the file libraries/base/LICENSE)
--
-- Maintainer : ffi@haskell.org
-- Stability : provisional
-- Portability : portable
--
-- Utilities for primitive marshaling
--
-----------------------------------------------------------------------------
module Foreign.Marshal.Utils (
-- * General marshalling utilities
-- ** Combined allocation and marshalling
--
with, -- :: Storable a => a -> (Ptr a -> IO b) -> IO b
new, -- :: Storable a => a -> IO (Ptr a)
-- ** Marshalling of Boolean values (non-zero corresponds to 'True')
--
fromBool, -- :: Num a => Bool -> a
toBool, -- :: Num a => a -> Bool
-- ** Marshalling of Maybe values
--
maybeNew, -- :: ( a -> IO (Ptr a))
-- -> (Maybe a -> IO (Ptr a))
maybeWith, -- :: ( a -> (Ptr b -> IO c) -> IO c)
-- -> (Maybe a -> (Ptr b -> IO c) -> IO c)
maybePeek, -- :: (Ptr a -> IO b )
-- -> (Ptr a -> IO (Maybe b))
-- ** Marshalling lists of storable objects
--
withMany, -- :: (a -> (b -> res) -> res) -> [a] -> ([b] -> res) -> res
-- ** Haskellish interface to memcpy and memmove
-- | (argument order: destination, source)
--
copyBytes, -- :: Ptr a -> Ptr a -> Int -> IO ()
moveBytes, -- :: Ptr a -> Ptr a -> Int -> IO ()
) where
import Data.Maybe
import Foreign.Ptr ( Ptr, nullPtr )
import Foreign.Storable ( Storable(poke) )
import Foreign.C.Types ( CSize )
import Foreign.Marshal.Alloc ( malloc, alloca )
-- combined allocation and marshalling
-- -----------------------------------
-- |Allocate a block of memory and marshal a value into it
-- (the combination of 'malloc' and 'poke').
-- The size of the area allocated is determined by the 'Foreign.Storable.sizeOf'
-- method from the instance of 'Storable' for the appropriate type.
--
-- The memory may be deallocated using 'Foreign.Marshal.Alloc.free' or
-- 'Foreign.Marshal.Alloc.finalizerFree' when no longer required.
--
new :: Storable a => a -> IO (Ptr a)
new val =
do
ptr <- malloc
poke ptr val
return ptr
-- |@'with' val f@ executes the computation @f@, passing as argument
-- a pointer to a temporarily allocated block of memory into which
-- @val@ has been marshalled (the combination of 'alloca' and 'poke').
--
-- The memory is freed when @f@ terminates (either normally or via an
-- exception), so the pointer passed to @f@ must /not/ be used after this.
--
with :: Storable a => a -> (Ptr a -> IO b) -> IO b
with val f =
alloca $ \ptr -> do
poke ptr val
res <- f ptr
return res
-- marshalling of Boolean values (non-zero corresponds to 'True')
-- -----------------------------
-- |Convert a Haskell 'Bool' to its numeric representation
--
fromBool :: Num a => Bool -> a
fromBool False = 0
fromBool True = 1
-- |Convert a Boolean in numeric representation to a Haskell value
--
toBool :: Num a => a -> Bool
toBool = (/= 0)
-- marshalling of Maybe values
-- ---------------------------
-- |Allocate storage and marshall a storable value wrapped into a 'Maybe'
--
-- * the 'nullPtr' is used to represent 'Nothing'
--
maybeNew :: ( a -> IO (Ptr a))
-> (Maybe a -> IO (Ptr a))
maybeNew = maybe (return nullPtr)
-- |Converts a @withXXX@ combinator into one marshalling a value wrapped
-- into a 'Maybe', using 'nullPtr' to represent 'Nothing'.
--
maybeWith :: ( a -> (Ptr b -> IO c) -> IO c)
-> (Maybe a -> (Ptr b -> IO c) -> IO c)
maybeWith = maybe ($ nullPtr)
-- |Convert a peek combinator into a one returning 'Nothing' if applied to a
-- 'nullPtr'
--
maybePeek :: (Ptr a -> IO b) -> Ptr a -> IO (Maybe b)
maybePeek peek ptr | ptr == nullPtr = return Nothing
| otherwise = do a <- peek ptr; return (Just a)
-- marshalling lists of storable objects
-- -------------------------------------
-- |Replicates a @withXXX@ combinator over a list of objects, yielding a list of
-- marshalled objects
--
withMany :: (a -> (b -> res) -> res) -- withXXX combinator for one object
-> [a] -- storable objects
-> ([b] -> res) -- action on list of marshalled obj.s
-> res
withMany _ [] f = f []
withMany withFoo (x:xs) f = withFoo x $ \x' ->
withMany withFoo xs (\xs' -> f (x':xs'))
-- Haskellish interface to memcpy and memmove
-- ------------------------------------------
-- |Copies the given number of bytes from the second area (source) into the
-- first (destination); the copied areas may /not/ overlap
--
copyBytes :: Ptr a -> Ptr a -> Int -> IO ()
copyBytes dest src size = memcpy dest src (fromIntegral size)
-- |Copies the given number of elements from the second area (source) into the
-- first (destination); the copied areas /may/ overlap
--
moveBytes :: Ptr a -> Ptr a -> Int -> IO ()
moveBytes dest src size = memmove dest src (fromIntegral size)
-- auxilliary routines
-- -------------------
-- |Basic C routines needed for memory copying
--
foreign import ccall unsafe "string.h" memcpy :: Ptr a -> Ptr a -> CSize -> IO ()
foreign import ccall unsafe "string.h" memmove :: Ptr a -> Ptr a -> CSize -> IO ()
|