[project @ 2002-09-29 20:24:00 by panne]

[ghc-base.git] / GHC / IO.hs

diff --git a/GHC/IO.hs b/GHC/IO.hs
index 32018e9..b3d590a 100644 (file)
--- a/GHC/IO.hs
+++ b/GHC/IO.hs
@@ -168,10 +168,13 @@ hGetLineBufferedLoop handle_ ref
 #endif
 
   xs <- unpack raw r off
+
+  -- if eol == True, then off is the offset of the '\n'
+  -- otherwise off == w and the buffer is now empty.
   if eol
-       then do if w == off + 1
-                  then writeIORef ref buf{ bufRPtr=0, bufWPtr=0 }
-                  else writeIORef ref buf{ bufRPtr = off + 1 }
+       then do if (w == off + 1)
+                       then writeIORef ref buf{ bufRPtr=0, bufWPtr=0 }
+                       else writeIORef ref buf{ bufRPtr = off + 1 }
                return (concat (reverse (xs:xss)))
        else do
             maybe_buf <- maybeFillReadBuffer (haFD handle_) True (haIsStream handle_)
@@ -179,10 +182,12 @@ hGetLineBufferedLoop handle_ ref
             case maybe_buf of
                -- Nothing indicates we caught an EOF, and we may have a
                -- partial line to return.
-               Nothing -> let str = concat (reverse (xs:xss)) in
-                          if not (null str)
-                             then return str
-                             else ioe_EOF
+               Nothing -> do
+                    writeIORef ref buf{ bufRPtr=0, bufWPtr=0 }
+                    let str = concat (reverse (xs:xss))
+                    if not (null str)
+                       then return str
+                       else ioe_EOF
                Just new_buf -> 
                     hGetLineBufferedLoop handle_ ref new_buf (xs:xss)
 
@@ -607,7 +612,8 @@ hPutBuf :: Handle                   -- handle to write to
        -> Int                          -- number of bytes of data in buffer
        -> IO ()
 hPutBuf handle ptr count
-  | count <= 0 = illegalBufferSize handle "hPutBuf" count
+  | count == 0 = return ()
+  | count <  0 = illegalBufferSize handle "hPutBuf" count
   | otherwise = 
     wantWritableHandle "hPutBuf" handle $ 
       \ handle_@Handle__{ haFD=fd, haBuffer=ref, haIsStream=is_stream } -> do
@@ -647,7 +653,8 @@ writeChunk fd ptr bytes = loop 0 bytes
 
 hGetBuf :: Handle -> Ptr a -> Int -> IO Int
 hGetBuf handle ptr count
-  | count <= 0 = illegalBufferSize handle "hGetBuf" count
+  | count == 0 = return 0
+  | count <  0 = illegalBufferSize handle "hGetBuf" count
   | otherwise = 
       wantReadableHandle "hGetBuf" handle $ 
        \ handle_@Handle__{ haFD=fd, haBuffer=ref } -> do
@@ -694,6 +701,7 @@ slurpFile fname = do
     ioError (userError "slurpFile: file too big")
    else do
     let sz_i = fromIntegral sz
+    if sz_i == 0 then return (nullPtr, 0) else do
     chunk <- mallocBytes sz_i
     r <- hGetBuf handle chunk sz_i
     hClose handle