%
-% (c) The GRASP/AQUA Project, Glasgow University, 1997-1998
+% (c) The University of Glasgow, 1997-2003
%
\section{String buffers}
Buffers for scanning string input stored in external arrays.
\begin{code}
-
-{-# OPTIONS -optc-DNON_POSIX_SOURCE #-}
-
module StringBuffer
(
- StringBuffer,
+ StringBuffer(..),
+ -- non-abstract for vs/HaskellService
- -- creation/destruction
+ -- * Creation/destruction
hGetStringBuffer, -- :: FilePath -> IO StringBuffer
stringToStringBuffer, -- :: String -> IO StringBuffer
- freeStringBuffer, -- :: StringBuffer -> IO ()
-
- -- Lookup
- currentChar, -- :: StringBuffer -> Char
- currentChar#, -- :: StringBuffer -> Char#
- indexSBuffer, -- :: StringBuffer -> Int -> Char
- indexSBuffer#, -- :: StringBuffer -> Int# -> Char#
- -- relative lookup, i.e, currentChar = lookAhead 0
- lookAhead, -- :: StringBuffer -> Int -> Char
- lookAhead#, -- :: StringBuffer -> Int# -> Char#
-
- -- offsets
- currentIndex#, -- :: StringBuffer -> Int#
- lexemeIndex, -- :: StringBuffer -> Int#
-
- -- moving the end point of the current lexeme.
- setCurrentPos#, -- :: StringBuffer -> Int# -> StringBuffer
- incLexeme, -- :: StringBuffer -> StringBuffer
- decLexeme, -- :: StringBuffer -> StringBuffer
-
- -- move the start and end lexeme pointer on by x units.
- stepOn, -- :: StringBuffer -> StringBuffer
- stepOnBy#, -- :: StringBuffer -> Int# -> StringBuffer
- stepOnTo#, -- :: StringBuffer -> Int# -> StringBuffer
- stepOnUntil, -- :: (Char -> Bool) -> StringBuffer -> StringBuffer
- stepOnUntilChar#, -- :: StringBuffer -> Char# -> StringBuffer
- stepOverLexeme, -- :: StringBuffer -> StringBuffer
- scanNumLit, -- :: Int -> StringBuffer -> (Int, StringBuffer)
- squeezeLexeme, -- :: StringBuffer -> Int# -> StringBuffer
- mergeLexemes, -- :: StringBuffer -> StringBuffer -> StringBuffer
- expandWhile, -- :: (Char -> Bool) -> StringBuffer -> StringBuffer
- expandWhile#, -- :: (Char# -> Bool) -> StringBuffer -> StringBuffer
- expandUntilMatch, -- :: StrinBuffer -> String -> StringBuffer
- -- at or beyond end of buffer?
- bufferExhausted, -- :: StringBuffer -> Bool
- emptyLexeme, -- :: StringBuffer -> Bool
-
- -- matching
- prefixMatch, -- :: StringBuffer -> String -> Bool
- untilEndOfString#, -- :: StringBuffer -> Int#
-
- -- conversion
- lexemeToString, -- :: StringBuffer -> String
- lexemeToFastString, -- :: StringBuffer -> FastString
- ) where
-#include "HsVersions.h"
+ -- * Lookup
+ currentChar, -- :: StringBuffer -> Char
+ prevChar, -- :: StringBuffer -> Char -> Char
+ lookAhead, -- :: StringBuffer -> Int -> Char
+ atEnd, -- :: StringBuffer -> Bool
+ -- * Moving
+ stepOn, stepOnBy,
-#if __GLASGOW_HASKELL__ < 411
-import PrelAddr ( Addr(..) )
-import Panic ( panic )
-#else
-import Addr ( Addr(..) )
-#if __GLASGOW_HASKELL__ < 503
-import Ptr ( Ptr(..) )
-#else
-import GHC.Ptr ( Ptr(..) )
-#endif
-#endif
+ -- * Conversion
+ lexemeToString, -- :: StringBuffer -> Int -> String
+ lexemeToFastString, -- :: StringBuffer -> Int -> FastString
+ ) where
-#if __GLASGOW_HASKELL__ < 501
-import Char ( chr )
-#elif __GLASGOW_HASKELL__ < 503
-import PrelIO ( hGetcBuffered )
-#else
-import GHC.IO ( hGetcBuffered )
-#endif
+#include "HsVersions.h"
-import PrimPacked
import FastString
+import Panic
-import GlaExts
-import Foreign
-import IO ( openFile, isEOFError )
-import Addr
-import Exception ( bracket )
+import GLAEXTS
-import CString ( unpackCStringBA )
+import Foreign
#if __GLASGOW_HASKELL__ < 503
import PrelIOBase
import PrelHandle
#else
import GHC.IOBase
-import GHC.Handle
+import GHC.IO ( slurpFile )
#endif
-import Char ( isDigit )
-\end{code}
+import IO ( openFile, hFileSize, IOMode(ReadMode) )
+#if __GLASGOW_HASKELL__ >= 601
+import System.IO ( openBinaryFile )
+#else
+import IOExts ( openFileEx, IOModeEx(..) )
+#endif
+
+#if __GLASGOW_HASKELL__ < 503
+import IArray ( listArray )
+import ArrayBase ( UArray(..) )
+import MutableArray
+import IOExts ( hGetBufBA )
+#else
+import Data.Array.IArray ( listArray )
+import Data.Array.MArray ( unsafeFreeze, newArray_ )
+import Data.Array.Base ( UArray(..) )
+import Data.Array.IO ( IOArray, hGetArray )
+#endif
+
+import Char ( ord )
+
+#if __GLASGOW_HASKELL__ < 601
+openBinaryFile fp mode = openFileEx fp (BinaryMode mode)
+#endif
+-- -----------------------------------------------------------------------------
+-- The StringBuffer type
+
+-- A StringBuffer is a ByteArray# with a pointer into it. We also cache
+-- the length of the ByteArray# for speed.
-\begin{code}
data StringBuffer
= StringBuffer
- Addr#
+ ByteArray#
Int# -- length
- Int# -- lexeme start
Int# -- current pos
-\end{code}
-\begin{code}
instance Show StringBuffer where
- showsPrec _ s = showString ""
-\end{code}
+ showsPrec _ s = showString "<stringbuffer>"
+
+-- -----------------------------------------------------------------------------
+-- Creation / Destruction
-\begin{code}
hGetStringBuffer :: FilePath -> IO StringBuffer
hGetStringBuffer fname = do
- (a, read) <- slurpFileExpandTabs fname
-
- -- 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# end#)
- return (StringBuffer a# end# 0# 0#)
-
-unsafeWriteBuffer :: StringBuffer -> Int# -> Char# -> StringBuffer
-unsafeWriteBuffer s@(StringBuffer a _ _ _) i# ch# =
- unsafePerformIO (
- _casm_ `` ((char *)%0)[(int)%1]=(char)%2; '' (A# a) (I# i#) (C# ch#) >>= \ () ->
- return s
- )
-\end{code}
-
------------------------------------------------------------------------------
--- Turn a String into a StringBuffer
-
-\begin{code}
-stringToStringBuffer :: String -> IO StringBuffer
-freeStringBuffer :: StringBuffer -> IO ()
-
-#if __GLASGOW_HASKELL__ >= 411
-stringToStringBuffer str =
- do let sz@(I# sz#) = length str
- (Ptr a#) <- mallocBytes (sz+1)
- fill_in str (A# a#)
- writeCharOffAddr (A# a#) sz '\0' -- sentinel
- return (StringBuffer a# sz# 0# 0#)
- where
- fill_in [] _ = return ()
- fill_in (c:cs) a = do
- writeCharOffAddr a 0 c
- fill_in cs (a `plusAddr` 1)
-
-freeStringBuffer (StringBuffer a# _ _ _) = Foreign.free (Ptr a#)
-#else
-stringToStringBuffer = panic "stringToStringBuffer: not implemented"
-freeStringBuffer sb = return ()
-#endif
-
-\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
- if sz_i == 0
- -- empty file: just allocate a buffer containing '\0'
- then do chunk <- allocMem 1
- writeCharOffAddr chunk 0 '\0'
- return (chunk, 0)
- else do let 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
+ h <- openBinaryFile fname ReadMode
+ size <- hFileSize h
+ let size_i@(I# sz#) = fromIntegral size
+#if __GLASGOW_HASKELL__ < 503
+ arr <- stToIO (newCharArray (0,size_i-1))
+ r <- hGetBufBA h arr size_i
#else
- wantReadableHandle "hGetChar" handle $
- \ handle_@Handle__{ haFD=fd, haBuffer=ref, haBufferMode=mode } ->
+ arr <- newArray_ (0,size_i-1)
+ r <- hGetArray h arr size_i
#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
-#if __GLASGOW_HASKELL__ >= 503
- new_buf <- fillReadBuffer fd True False buf
+ if (r /= size_i)
+ then ioError (userError "short read of file")
+ else do
+#if __GLASGOW_HASKELL__ < 503
+ frozen <- stToIO (unsafeFreezeByteArray arr)
+ case frozen of
+ ByteArray _ _ bytearr# -> return (StringBuffer bytearr# sz# 0#)
#else
- new_buf <- fillReadBuffer fd True buf
-#endif
- hGetcBuffered fd ref new_buf)
- `catch` \e -> if isEOFError e
- then return '\xFFFF'
- else ioError e
- case ch of
- '\xFFFF' -> return (chunk, I# off)
+ frozen <- unsafeFreeze arr
+ case frozen of
+ UArray _ _ bytearr# -> return (StringBuffer bytearr# sz# 0#)
#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#))
- 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"
+
+#if __GLASGOW_HASKELL__ >= 502
+stringToStringBuffer str = do
+ let size@(I# sz#) = length str
+ arr = listArray (0,size-1) (map (fromIntegral.ord) str)
+ :: UArray Int Word8
+ case arr of
+ UArray _ _ bytearr# -> return (StringBuffer bytearr# sz# 0#)
#else
- then ioException (IOError Nothing ResourceExhausted "malloc"
- "out of memory" Nothing)
+stringToStringBuffer = panic "stringToStringBuffer: not implemented"
#endif
- else return chunk
-\end{code}
-Lookup
+-- -----------------------------------------------------------------------------
+-- Lookup
-\begin{code}
currentChar :: StringBuffer -> Char
-currentChar sb = case currentChar# sb of c -> C# c
+currentChar (StringBuffer arr# l# current#) =
+ ASSERT(current# <# l#)
+ C# (indexCharArray# arr# current#)
-lookAhead :: StringBuffer -> Int -> Char
-lookAhead sb (I# i#) = case lookAhead# sb i# of c -> C# c
-
-indexSBuffer :: StringBuffer -> Int -> Char
-indexSBuffer sb (I# i#) = case indexSBuffer# sb i# of c -> C# c
-
-currentChar# :: StringBuffer -> Char#
-indexSBuffer# :: StringBuffer -> Int# -> Char#
-lookAhead# :: StringBuffer -> Int# -> Char#
-currentChar# (StringBuffer fo# _ _ current#) = indexCharOffAddr# fo# current#
-indexSBuffer# (StringBuffer fo# _ _ _) i# = indexCharOffAddr# fo# i#
-
- -- relative lookup, i.e, currentChar = lookAhead 0
-lookAhead# (StringBuffer fo# _ _ c#) i# = indexCharOffAddr# fo# (c# +# i#)
-
-currentIndex# :: StringBuffer -> Int#
-currentIndex# (StringBuffer fo# _ _ c#) = c#
+prevChar :: StringBuffer -> Char -> Char
+prevChar (StringBuffer _ _ 0#) deflt = deflt
+prevChar s deflt = lookAhead s (-1)
-lexemeIndex :: StringBuffer -> Int#
-lexemeIndex (StringBuffer fo# _ c# _) = c#
-\end{code}
-
- moving the start point of the current lexeme.
-
-\begin{code}
- -- moving the end point of the current lexeme.
-setCurrentPos# :: StringBuffer -> Int# -> StringBuffer
-setCurrentPos# (StringBuffer fo l# s# c#) i# =
- StringBuffer fo l# s# (c# +# i#)
+lookAhead :: StringBuffer -> Int -> Char
+lookAhead (StringBuffer arr# l# c#) (I# i#) =
+ ASSERT(off <# l# && off >=# 0#)
+ C# (indexCharArray# arr# off)
+ where
+ off = c# +# i#
--- augmenting the current lexeme by one.
-incLexeme :: StringBuffer -> StringBuffer
-incLexeme (StringBuffer fo l# s# c#) = StringBuffer fo l# s# (c# +# 1#)
+-- -----------------------------------------------------------------------------
+-- Moving
-decLexeme :: StringBuffer -> StringBuffer
-decLexeme (StringBuffer fo l# s# c#) = StringBuffer fo l# s# (c# -# 1#)
+stepOn :: StringBuffer -> StringBuffer
+stepOn s = stepOnBy 1 s
-\end{code}
+stepOnBy :: Int -> StringBuffer -> StringBuffer
+stepOnBy (I# i#) (StringBuffer fo# l# c#) = StringBuffer fo# l# (c# +# i#)
--- move the start and end point of the buffer on by
--- x units.
+atEnd :: StringBuffer -> Bool
+atEnd (StringBuffer _ l# c#) = l# ==# c#
-\begin{code}
-stepOn :: StringBuffer -> StringBuffer
-stepOn (StringBuffer fo l# s# c#) = StringBuffer fo l# (s# +# 1#) (s# +# 1#) -- assume they're the same.
-
-stepOnBy# :: StringBuffer -> Int# -> StringBuffer
-stepOnBy# (StringBuffer fo# l# s# c#) i# =
- case s# +# i# of
- new_s# -> StringBuffer fo# l# new_s# new_s#
-
--- jump to pos.
-stepOnTo# :: StringBuffer -> Int# -> StringBuffer
-stepOnTo# (StringBuffer fo l _ _) s# = StringBuffer fo l s# s#
-
-squeezeLexeme :: StringBuffer -> Int# -> StringBuffer
-squeezeLexeme (StringBuffer fo l s# c#) i# = StringBuffer fo l (s# +# i#) c#
-
-mergeLexemes :: StringBuffer -> StringBuffer -> StringBuffer
-mergeLexemes (StringBuffer fo l s# _) (StringBuffer _ _ _ c#)
- = StringBuffer fo l s# c#
-
-stepOnUntil :: (Char -> Bool) -> StringBuffer -> StringBuffer
-
-stepOnUntil pred (StringBuffer fo l# s# c#) =
- loop c#
- where
- loop c# =
- case indexCharOffAddr# fo c# of
- ch# | pred (C# ch#) -> StringBuffer fo l# c# c#
- | ch# `eqChar#` '\NUL'# && c# >=# l# -> StringBuffer fo l# l# l# -- EOB, return immediately.
- | otherwise -> loop (c# +# 1#)
-
-stepOverLexeme :: StringBuffer -> StringBuffer
-stepOverLexeme (StringBuffer fo l s# c#) = StringBuffer fo l c# c#
-
-expandWhile :: (Char -> Bool) -> StringBuffer -> StringBuffer
-expandWhile pred (StringBuffer fo l# s# c#) =
- loop c#
- where
- loop c# =
- case indexCharOffAddr# fo c# of
- ch# | pred (C# ch#) -> loop (c# +# 1#)
- | ch# `eqChar#` '\NUL'# && c# >=# l# -> StringBuffer fo l# l# l# -- EOB, return immediately.
- | otherwise -> StringBuffer fo l# s# c#
-
-expandWhile# :: (Char# -> Bool) -> StringBuffer -> StringBuffer
-expandWhile# pred (StringBuffer fo l# s# c#) =
- loop c#
- where
- loop c# =
- case indexCharOffAddr# fo c# of
- ch# | pred ch# -> loop (c# +# 1#)
- | ch# `eqChar#` '\NUL'# && c# >=# l# -> StringBuffer fo l# s# c# -- EOB, return immediately.
- | otherwise -> StringBuffer fo l# s# c#
-
-scanNumLit :: Integer -> StringBuffer -> (Integer,StringBuffer)
-scanNumLit acc (StringBuffer fo l# s# c#) =
- loop acc c#
- where
- loop acc c# =
- case indexCharOffAddr# fo c# of
- ch# | isDigit (C# ch#) -> loop (acc*10 + (toInteger (I# (ord# ch# -# ord# '0'#)))) (c# +# 1#)
- | ch# `eqChar#` '\NUL'# && c# >=# l# -> (acc, StringBuffer fo l# s# c#) -- EOB, return immediately.
- | otherwise -> (acc,StringBuffer fo l# s# c#)
-
-
-expandUntilMatch :: StringBuffer -> String -> Maybe StringBuffer
-expandUntilMatch (StringBuffer fo l# s# c#) str =
- loop c# str
- where
- loop c# [] = Just (StringBuffer fo l# s# c#)
- loop c# ((C# x#):xs) =
- case indexCharOffAddr# fo c# of
- ch# | ch# `eqChar#` '\NUL'# && c# >=# l# -> Nothing
- | ch# `eqChar#` x# -> loop (c# +# 1#) xs
- | otherwise -> loop (c# +# 1#) str
-
-\end{code}
+-- -----------------------------------------------------------------------------
+-- Conversion
-\begin{code}
- -- at or beyond end of buffer?
-bufferExhausted :: StringBuffer -> Bool
-bufferExhausted (StringBuffer fo l# _ c#) = c# >=# l#
-
-emptyLexeme :: StringBuffer -> Bool
-emptyLexeme (StringBuffer fo l# s# c#) = s# ==# c#
-
- -- matching
-prefixMatch :: StringBuffer -> String -> Maybe StringBuffer
-prefixMatch (StringBuffer fo l# s# c#) str =
- loop c# str
- where
- loop c# [] = Just (StringBuffer fo l# s# c#)
- loop c# ((C# x#):xs)
- | indexCharOffAddr# fo c# `eqChar#` x#
- = loop (c# +# 1#) xs
- | otherwise
- = Nothing
-
-untilEndOfString# :: StringBuffer -> StringBuffer
-untilEndOfString# (StringBuffer fo l# s# c#) =
- loop c#
- where
- getch# i# = indexCharOffAddr# fo i#
-
- loop c# =
- case getch# c# of
- '\"'# ->
- case getch# (c# -# 1#) of
- '\\'# ->
- -- looks like an escaped something or other to me,
- -- better count the number of "\\"s that are immediately
- -- preceeding to decide if the " is escaped.
- let
- odd_slashes flg i# =
- case getch# i# of
- '\\'# -> odd_slashes (not flg) (i# -# 1#)
- _ -> flg
- in
- if odd_slashes True (c# -# 2#) then
- -- odd number, " is ecaped.
- loop (c# +# 1#)
- else -- a real end of string delimiter after all.
- StringBuffer fo l# s# c#
- _ -> StringBuffer fo l# s# c#
- '\NUL'# ->
- if c# >=# l# then -- hit sentinel, this doesn't look too good..
- StringBuffer fo l# l# l#
- else
- loop (c# +# 1#)
- _ -> loop (c# +# 1#)
-
-
-stepOnUntilChar# :: StringBuffer -> Char# -> StringBuffer
-stepOnUntilChar# (StringBuffer fo l# s# c#) x# =
- loop c#
+lexemeToString :: StringBuffer -> Int -> String
+lexemeToString _ 0 = ""
+lexemeToString (StringBuffer arr# _ current#) (I# len#) = unpack current#
where
- loop c#
- | c# >=# l# || indexCharOffAddr# fo c# `eqChar#` x#
- = StringBuffer fo l# c# c#
- | otherwise
- = loop (c# +# 1#)
-
- -- conversion
-lexemeToString :: StringBuffer -> String
-lexemeToString (StringBuffer fo _ start_pos# current#) =
- if start_pos# ==# current# then
- ""
- else
- unpackCStringBA (copySubStr (A# fo) (I# start_pos#) (I# (current# -# start_pos#)))
-
-lexemeToFastString :: StringBuffer -> FastString
-lexemeToFastString (StringBuffer fo l# start_pos# current#) =
- if start_pos# ==# current# then
- mkFastString ""
- else
- mkFastSubString (A# fo) (I# start_pos#) (I# (current# -# start_pos#))
+ end = current# +# len#
+
+ unpack nh
+ | nh >=# end = []
+ | otherwise = C# ch : unpack (nh +# 1#)
+ where
+ ch = indexCharArray# arr# nh
+
+lexemeToFastString :: StringBuffer -> Int -> FastString
+lexemeToFastString _ 0 = mkFastString ""
+lexemeToFastString (StringBuffer fo _ current#) (I# len) =
+ mkFastSubStringBA# fo current# len
\end{code}
projects / ghc-hetmet.git / blobdiff