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Add 'fillBytes' to Foreign.Marshal.Utils.

fillBytes uses 'memset' to fill a memory area with a given byte value.

Reviewed By: austin, hvr

Differential Revision: https://phabricator.haskell.org/D465
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ifesdjeen authored and hvr committed Nov 21, 2014
1 parent c0ad5bc commit 35833122da8ddb2c0e7aaee0c9b6089af52e38b1
Showing with 19 additions and 2 deletions.
  1. +17 −2 libraries/base/Foreign/Marshal/Utils.hs
  2. +2 −0 libraries/base/changelog.md
@@ -43,13 +43,18 @@ module Foreign.Marshal.Utils (
--
copyBytes,
moveBytes,
+
+ -- ** Filling up memory area with required values
+ --
+ fillBytes,
) where
import Data.Maybe
import Foreign.Ptr ( Ptr, nullPtr )
import Foreign.Storable ( Storable(poke) )
-import Foreign.C.Types ( CSize(..) )
+import Foreign.C.Types ( CSize(..), CInt(..) )
import Foreign.Marshal.Alloc ( malloc, alloca )
+import Data.Word ( Word8 )
import GHC.Real ( fromIntegral )
import GHC.Num
@@ -161,6 +166,16 @@ moveBytes :: Ptr a -> Ptr a -> Int -> IO ()
moveBytes dest src size = do _ <- memmove dest src (fromIntegral size)
return ()
+-- Filling up memory area with required values
+-- -------------------------------------------
+
+-- |Fill a given number of bytes in memory area with a byte value.
+--
+-- /Since: 4.8.0.0/
+fillBytes :: Ptr a -> Word8 -> Int -> IO ()
+fillBytes dest char size = do
+ _ <- memset dest (fromIntegral char) (fromIntegral size)
+ return ()
-- auxilliary routines
-- -------------------
@@ -169,4 +184,4 @@ moveBytes dest src size = do _ <- memmove dest src (fromIntegral size)
--
foreign import ccall unsafe "string.h" memcpy :: Ptr a -> Ptr a -> CSize -> IO (Ptr a)
foreign import ccall unsafe "string.h" memmove :: Ptr a -> Ptr a -> CSize -> IO (Ptr a)
-
+foreign import ccall unsafe "string.h" memset :: Ptr a -> CInt -> CSize -> IO (Ptr a)
@@ -102,6 +102,8 @@
* Add `scanl'`, a strictly accumulating version of `scanl`, to `Data.List`
and `Data.OldList`. (#9368)
+ * Add `fillBytes` to `Foreign.Marshal.Utils`.
+
## 4.7.0.1 *Jul 2014*
* Bundled with GHC 7.8.3

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