[project @ 2001-08-24 14:41:09 by simonmar]

correct off-by-one error in hGetStringBuffer

diff --git a/ghc/compiler/utils/StringBuffer.lhs b/ghc/compiler/utils/StringBuffer.lhs
index dfe061e..c72be06 100644 (file)
--- a/ghc/compiler/utils/StringBuffer.lhs
+++ b/ghc/compiler/utils/StringBuffer.lhs
@@ -129,11 +129,17 @@ hGetStringBuffer expand_tabs fname = do
                                    return (A# a#, read)
 #endif
 
-   let (A# a#) = a;  (I# read#) = read
+       -- urk! slurpFile gives us a buffer that doesn't have room for
+       -- the sentinel.  Assume it has a final newline for now, and overwrite
+       -- that with the sentinel.  slurpFileExpandTabs (below) leaves room
+       -- for the sentinel.
+   let  (A# a#) = a;  
+       (I# read#) = read;
+       end# = read# -# 1#
 
          -- add sentinel '\NUL'
-   _casm_ `` ((char *)%0)[(int)%1]=(char)0; '' (A# a#) (I# (read# -# 1#))
-   return (StringBuffer a# read# 0# 0#)
+   _casm_ `` ((char *)%0)[(int)%1]=(char)0; '' (A# a#) (I# end#)
+   return (StringBuffer a# end# 0# 0#)
 
 unsafeWriteBuffer :: StringBuffer -> Int# -> Char# -> StringBuffer
 unsafeWriteBuffer s@(StringBuffer a _ _ _) i# ch# =
@@ -269,7 +275,7 @@ trySlurp handle sz_i chunk =
 #if __GLASGOW_HASKELL__ < 404
   writeHandle handle handle_
 #endif
-  return (chunk', rc+1 {-room for sentinel-})
+  return (chunk', rc+1 {- room for sentinel -})
 
 
 reAllocMem :: Addr -> Int -> IO Addr