[project @ 2004-12-24 12:12:28 by krasimir]

minor performance update for withCAStringLen and newCAStringLen functions.
We don't need to calculate the string length twice.

diff --git a/Foreign/C/String.hs b/Foreign/C/String.hs
index b03d32b..720330c 100644 (file)
--- a/Foreign/C/String.hs
+++ b/Foreign/C/String.hs
@@ -278,12 +278,10 @@ newCAStringLen str  = do
 newCAStringLen str = do
   ptr <- mallocArray0 len
   let
-       go [] n     = n `seq` return () -- make it strict in n
+       go []     n = n `seq` return n  -- make it strict in n
        go (c:cs) n = do pokeElemOff ptr n (castCharToCChar c); go cs (n+1)
-  go str 0
+  len <- go str 0
   return (ptr, len)
-  where
-    len = length str
 #endif
 
 -- | Marshal a Haskell string into a NUL terminated C string using temporary
@@ -325,13 +323,11 @@ withCAStringLen str act  = withArray (charsToCChars str) $ act . pairLength str
 withCAStringLen str f =
   allocaArray len $ \ptr ->
       let
-       go [] n     = n `seq` return () -- make it strict in n
+       go []     n = n `seq` return n  -- make it strict in n
        go (c:cs) n = do pokeElemOff ptr n (castCharToCChar c); go cs (n+1)
       in do
-      go str 0
+      len <- go str 0
       f (ptr,len)
-  where
-    len = length str
 #endif
 
 -- auxiliary definitions