[commit: vector] master: Use more efficient mallocPlainForeignPtrBytes when available (676d11c)

[Roman Leshchinskiy]

Repository : ssh://darcs.haskell.org//srv/darcs/packages/vector

On branch  : master

http://hackage.haskell.org/trac/ghc/changeset/676d11c47b3b6e8a6bfa29d13e4d7675c1eb30a8

>---------------------------------------------------------------

commit 676d11c47b3b6e8a6bfa29d13e4d7675c1eb30a8
Author: Bas van Dijk <v.dijk.bas at gmail.com>
Date:   Mon Apr 18 14:28:27 2011 +0000

    Use more efficient mallocPlainForeignPtrBytes when available

>---------------------------------------------------------------

 Data/Vector/Storable/Mutable.hs |   19 ++++++++++++++++++-
 1 files changed, 18 insertions(+), 1 deletions(-)

diff --git a/Data/Vector/Storable/Mutable.hs b/Data/Vector/Storable/Mutable.hs
index 409885e..c1913f7 100644
--- a/Data/Vector/Storable/Mutable.hs
+++ b/Data/Vector/Storable/Mutable.hs
@@ -60,6 +60,11 @@ import Data.Vector.Storable.Internal
 
 import Foreign.Storable
 import Foreign.ForeignPtr
+
+#if __GLASGOW_HASKELL__ >= 605
+import GHC.ForeignPtr (mallocPlainForeignPtrBytes)
+#endif
+
 import Foreign.Ptr
 import Foreign.Marshal.Array ( advancePtr, copyArray )
 import Foreign.C.Types ( CInt )
@@ -100,7 +105,7 @@ instance Storable a => G.MVector MVector a where
   basicUnsafeNew n
     = unsafePrimToPrim
     $ do
-        fp <- mallocForeignPtrArray n
+        fp <- mallocVector n
         withForeignPtr fp $ \p -> return $ MVector p n fp
 
   {-# INLINE basicUnsafeRead #-}
@@ -120,6 +125,18 @@ instance Storable a => G.MVector MVector a where
       withForeignPtr fq $ \_ ->
       copyArray p q n
 
+{-# INLINE mallocVector #-}
+mallocVector :: Storable a => Int -> IO (ForeignPtr a)
+mallocVector =
+#if __GLASGOW_HASKELL__ >= 605
+    doMalloc undefined
+        where
+          doMalloc :: Storable b => b -> Int -> IO (ForeignPtr b)
+          doMalloc dummy size = mallocPlainForeignPtrBytes (size * sizeOf dummy)
+#else
+    mallocForeignPtrArray
+#endif
+
 -- Length information
 -- ------------------