[project @ 1998-12-09 17:52:09 by sof]

Added unpackCStringST - unmarshal C strings promptly

diff --git a/ghc/lib/std/PrelPack.lhs b/ghc/lib/std/PrelPack.lhs
index b9f2527..8f009cc 100644 (file)
--- a/ghc/lib/std/PrelPack.lhs
+++ b/ghc/lib/std/PrelPack.lhs
@@ -23,6 +23,7 @@ module PrelPack
        packNBytesST,      -- :: Int -> [Char] -> ST s (ByteArray Int)
 
        unpackCString,     -- :: Addr -> [Char]
+       unpackCStringST,   -- :: Addr -> ST s [Char]
        unpackNBytes,      -- :: Addr -> Int -> [Char]
        unpackNBytesST,    -- :: Addr -> Int -> ST s [Char]
        unpackNBytesAccST, -- :: Addr -> Int -> [Char] -> ST s [Char]
@@ -66,11 +67,22 @@ sequence of bytes into a list of @Char@s:
 
 \begin{code}
 unpackCString  :: Addr{- ptr. to NUL terminated string-} -> [Char]
-unpackCString a@(A# addr) = 
-  if a == ``NULL'' then
-     []
-  else
-     unpackCString# addr
+unpackCString a@(A# addr)
+  | a == nullAddr  = []
+  | otherwise     = unpackCString# addr
+     
+unpackCStringST  :: Addr{- ptr. to NUL terminated string-} -> ST s [Char]
+unpackCStringST a@(A# addr)
+  | a == nullAddr  = return []
+  | otherwise     = unpack 0#
+  where
+    unpack nh
+      | ch `eqChar#` '\0'# = return []
+      | otherwise         = do
+               ls <- unpack (nh +# 1#)
+               return ((C# ch ) : ls)
+      where
+       ch = indexCharOffAddr# addr nh
 
 unpackCString# :: Addr#  -> [Char]
 unpackCString# addr