[commit: packages/binary] master: Port ensureN to use withInputChunks. (384dd59)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/binary

On branch  : master
Link       : http://git.haskell.org/packages/binary.git/commitdiff/384dd591258b287547023dc38c99345cdd2797a5

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

commit 384dd591258b287547023dc38c99345cdd2797a5
Author: Lennart Kolmodin <kolmodin at google.com>
Date:   Sat May 30 14:28:10 2015 +0200

    Port ensureN to use withInputChunks.


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

384dd591258b287547023dc38c99345cdd2797a5
 src/Data/Binary/Get/Internal.hs | 16 ++++++----------
 1 file changed, 6 insertions(+), 10 deletions(-)

diff --git a/src/Data/Binary/Get/Internal.hs b/src/Data/Binary/Get/Internal.hs
index 6659727..804fde1 100644
--- a/src/Data/Binary/Get/Internal.hs
+++ b/src/Data/Binary/Get/Internal.hs
@@ -398,18 +398,14 @@ ensureN :: Int -> Get ()
 ensureN !n0 = C $ \inp ks -> do
   if B.length inp >= n0
     then ks inp ()
-    else runCont (go n0 []) inp ks
+    else runCont (withInputChunks n0 enoughChunks onSucc onFail >>= put) inp ks
   where -- might look a bit funny, but plays very well with GHC's inliner.
         -- GHC won't inline recursive functions, so we make ensureN non-recursive
-    go !n bss0 = C $ \inp ks ->
-      let n' = n - B.length inp
-          bss = inp : bss0
-      in if n' <= 0
-        then ks (B.concat $ reverse bss) ()
-        else
-          prompt'
-            (Fail (B.concat $ reverse bss) "not enough bytes")
-            (\inp' -> runCont (go n' bss) inp' ks)
+    enoughChunks n str
+      | B.length str >= n = Right (str,B.empty)
+      | otherwise = Left (n - B.length str)
+    onSucc = B.concat
+    onFail bss = C $ \_ _ -> Fail (B.concat bss) "not enough bytes"
 {-# INLINE ensureN #-}
 
 unsafeReadN :: Int -> (B.ByteString -> a) -> Get a