-\end{code}
-
------------------------------------------------------------------------------
-This very disturbing bit of code is used for expanding the tabs in a
-file before we start parsing it. Expanding the tabs early makes the
-lexer a lot simpler: we only have to record the beginning of the line
-in order to be able to calculate the column offset of the current
-token.
-
-We guess the size of the buffer required as 20% extra for
-expanded tabs, and enlarge it if necessary.
-
-\begin{code}
-getErrType :: IO Int
-getErrType = _ccall_ getErrType__
-
-slurpFileExpandTabs :: FilePath -> IO (Addr,Int)
-slurpFileExpandTabs fname = do
- bracket (openFile fname ReadMode) (hClose)
- (\ handle ->
- do sz <- hFileSize handle
- if sz > toInteger (maxBound::Int)
- then IOERROR (userError "slurpFile: file too big")
- else do
- let sz_i = fromInteger sz
- sz_i' = (sz_i * 12) `div` 10 -- add 20% for tabs
- chunk <- allocMem sz_i'
- trySlurp handle sz_i' chunk
- )
-
-trySlurp :: Handle -> Int -> Addr -> IO (Addr, Int)
-trySlurp handle sz_i chunk =
-#if __GLASGOW_HASKELL__ < 501
- wantReadableHandle "hGetChar" handle $ \ handle_ ->
- let fo = haFO__ handle_ in
-#else
- wantReadableHandle "hGetChar" handle $
- \ handle_@Handle__{ haFD=fd, haBuffer=ref, haBufferMode=mode } ->
-#endif
- let
- (I# chunk_sz) = sz_i
-
- tAB_SIZE = 8#
-
- slurpFile :: Int# -> Int# -> Addr -> Int# -> Int# -> IO (Addr, Int)
- slurpFile c off chunk chunk_sz max_off = slurp c off
- where
-
- slurp :: Int# -> Int# -> IO (Addr, Int)
- slurp c off | off >=# max_off = do
- let new_sz = chunk_sz *# 2#
- chunk' <- reAllocMem chunk (I# new_sz)
- slurpFile c off chunk' new_sz (new_sz -# (tAB_SIZE +# 1#))
- slurp c off = do
-#if __GLASGOW_HASKELL__ < 501
- intc <- mayBlock fo (_ccall_ fileGetc fo)
- if intc == ((-1)::Int)
- then do errtype <- getErrType
- if errtype == (19{-ERR_EOF-} :: Int)
- then return (chunk, I# off)
- else constructErrorAndFail "slurpFile"
- else case chr intc of
-#else
- buf <- readIORef ref
- ch <- (if not (bufferEmpty buf)
- then hGetcBuffered fd ref buf
- else do new_buf <- fillReadBuffer fd True buf
- hGetcBuffered fd ref new_buf)
- `catch` \e -> if isEOFError e
- then return '\xFFFF'
- else ioError e
- case ch of
- '\xFFFF' -> return (chunk, I# off)
-#endif
- '\t' -> tabIt c off
- ch -> do writeCharOffAddr chunk (I# off) ch
- let c' | ch == '\n' = 0#
- | otherwise = c +# 1#
- slurp c' (off +# 1#)
-
- tabIt :: Int# -> Int# -> IO (Addr, Int)
- -- can't run out of buffer in here, because we reserved an
- -- extra tAB_SIZE bytes at the end earlier.
- tabIt c off = do
- writeCharOffAddr chunk (I# off) ' '
- let c' = c +# 1#
- off' = off +# 1#
- if c' `remInt#` tAB_SIZE ==# 0#
- then slurp c' off'
- else tabIt c' off'
- in do
-
- -- allow space for a full tab at the end of the buffer
- -- (that's what the max_off thing is for),
- -- and add 1 to allow room for the final sentinel \NUL at
- -- the end of the file.
- (chunk', rc) <- slurpFile 0# 0# chunk chunk_sz (chunk_sz -# (tAB_SIZE +# 1#))
-#if __GLASGOW_HASKELL__ < 404
- writeHandle handle handle_
-#endif
- return (chunk', rc+1 {- room for sentinel -})
-
-
-reAllocMem :: Addr -> Int -> IO Addr
-reAllocMem ptr sz = do
- chunk <- _ccall_ realloc ptr sz
- if chunk == nullAddr
- then fail "reAllocMem"
- else return chunk
-
-allocMem :: Int -> IO Addr
-allocMem sz = do
- chunk <- _ccall_ malloc sz
- if chunk == nullAddr
-#if __GLASGOW_HASKELL__ < 501
- then constructErrorAndFail "allocMem"
-#else
- then ioException (IOError Nothing ResourceExhausted "malloc"
- "out of memory" Nothing)