Commit 468600be authored by Ian Lynagh's avatar Ian Lynagh

Fix warnings in FastString, and check for empty case in head/tail

parent 2b56761f
......@@ -2,13 +2,6 @@
% (c) The University of Glasgow, 1997-2006
%
\begin{code}
{-# OPTIONS -w #-}
-- The above warning supression flag is a temporary kludge.
-- While working on this module you are encouraged to remove it and fix
-- any warnings in the module. See
-- http://hackage.haskell.org/trac/ghc/wiki/Commentary/CodingStyle#Warnings
-- for details
{-
FastString: A compact, hash-consed, representation of character strings.
Comparison is O(1), and you can get a Unique from them.
......@@ -86,18 +79,19 @@ module FastString
import Encoding
import FastTypes
import FastFunctions
import Panic
import Foreign
import Foreign.C
import GHC.Exts
import System.IO
import System.IO.Unsafe ( unsafePerformIO )
import Control.Monad.ST ( stToIO )
import Data.IORef ( IORef, newIORef, readIORef, writeIORef )
import System.IO ( hPutBuf )
import Data.Maybe ( isJust )
#if !defined(__GLASGOW_HASKELL__)
import Data.Char ( ord )
#endif
import GHC.ST
import GHC.IOBase ( IO(..) )
import GHC.Ptr ( Ptr(..) )
......@@ -205,7 +199,7 @@ mkFastString# a# = mkFastStringBytes ptr (ptrStrLength ptr)
mkFastStringBytes :: Ptr Word8 -> Int -> FastString
mkFastStringBytes ptr len = unsafePerformIO $ do
ft@(FastStringTable uid tbl#) <- readIORef string_table
ft@(FastStringTable uid _) <- readIORef string_table
let
h = hashStr ptr len
add_it ls = do
......@@ -225,7 +219,7 @@ mkFastStringBytes ptr len = unsafePerformIO $ do
mkZFastStringBytes :: Ptr Word8 -> Int -> FastString
mkZFastStringBytes ptr len = unsafePerformIO $ do
ft@(FastStringTable uid tbl#) <- readIORef string_table
ft@(FastStringTable uid _) <- readIORef string_table
let
h = hashStr ptr len
add_it ls = do
......@@ -248,7 +242,7 @@ mkZFastStringBytes ptr len = unsafePerformIO $ do
-- the bytes if the string is new to the table.
mkFastStringForeignPtr :: Ptr Word8 -> ForeignPtr Word8 -> Int -> IO FastString
mkFastStringForeignPtr ptr fp len = do
ft@(FastStringTable uid tbl#) <- readIORef string_table
ft@(FastStringTable uid _) <- readIORef string_table
-- _trace ("hashed: "++show (I# h)) $
let
h = hashStr ptr len
......@@ -269,7 +263,7 @@ mkFastStringForeignPtr ptr fp len = do
mkZFastStringForeignPtr :: Ptr Word8 -> ForeignPtr Word8 -> Int -> IO FastString
mkZFastStringForeignPtr ptr fp len = do
ft@(FastStringTable uid tbl#) <- readIORef string_table
ft@(FastStringTable uid _) <- readIORef string_table
-- _trace ("hashed: "++show (I# h)) $
let
h = hashStr ptr len
......@@ -319,6 +313,7 @@ mkZFastString str =
pokeCAString (castPtr ptr) str
mkZFastStringForeignPtr ptr buf l
bucket_match :: [FastString] -> Int -> Ptr Word8 -> IO (Maybe FastString)
bucket_match [] _ _ = return Nothing
bucket_match (v@(FastString _ l _ buf _):ls) len ptr
| len == l = do
......@@ -328,26 +323,31 @@ bucket_match (v@(FastString _ l _ buf _):ls) len ptr
| otherwise =
bucket_match ls len ptr
mkNewFastString :: Int -> Ptr Word8 -> ForeignPtr Word8 -> Int
-> IO FastString
mkNewFastString uid ptr fp len = do
ref <- newIORef Nothing
n_chars <- countUTF8Chars ptr len
return (FastString uid len n_chars fp (UTF8Encoded ref))
mkNewZFastString uid ptr fp len = do
mkNewZFastString :: Int -> Ptr Word8 -> ForeignPtr Word8 -> Int
-> IO FastString
mkNewZFastString uid _ fp len = do
return (FastString uid len len fp ZEncoded)
copyNewFastString :: Int -> Ptr Word8 -> Int -> IO FastString
copyNewFastString uid ptr len = do
fp <- copyBytesToForeignPtr ptr len
ref <- newIORef Nothing
n_chars <- countUTF8Chars ptr len
return (FastString uid len n_chars fp (UTF8Encoded ref))
copyNewZFastString :: Int -> Ptr Word8 -> Int -> IO FastString
copyNewZFastString uid ptr len = do
fp <- copyBytesToForeignPtr ptr len
return (FastString uid len len fp ZEncoded)
copyBytesToForeignPtr :: Ptr Word8 -> Int -> IO (ForeignPtr Word8)
copyBytesToForeignPtr ptr len = do
fp <- mallocForeignPtrBytes len
withForeignPtr fp $ \ptr' -> copyBytes ptr' ptr len
......@@ -385,7 +385,7 @@ isZEncoded fs | ZEncoded <- enc fs = True
-- | Returns 'True' if this 'FastString' is not Z-encoded but already has
-- a Z-encoding cached (used in producing stats).
hasZEncoding :: FastString -> Bool
hasZEncoding fs@(FastString uid n_bytes _ fp enc) =
hasZEncoding (FastString _ _ _ _ enc) =
case enc of
ZEncoded -> False
UTF8Encoded ref ->
......@@ -406,7 +406,7 @@ unpackFS (FastString _ n_bytes _ buf enc) =
UTF8Encoded _ -> utf8DecodeString ptr n_bytes
bytesFS :: FastString -> [Word8]
bytesFS (FastString _ n_bytes _ buf enc) =
bytesFS (FastString _ n_bytes _ buf _) =
inlinePerformIO $ withForeignPtr buf $ \ptr ->
peekArray n_bytes ptr
......@@ -416,7 +416,7 @@ bytesFS (FastString _ n_bytes _ buf enc) =
-- memoized.
--
zEncodeFS :: FastString -> FastString
zEncodeFS fs@(FastString uid n_bytes _ fp enc) =
zEncodeFS fs@(FastString _ _ _ _ enc) =
case enc of
ZEncoded -> fs
UTF8Encoded ref ->
......@@ -436,7 +436,8 @@ concatFS :: [FastString] -> FastString
concatFS ls = mkFastString (Prelude.concat (map unpackFS ls)) -- ToDo: do better
headFS :: FastString -> Char
headFS (FastString _ n_bytes _ buf enc) =
headFS (FastString _ 0 _ _ _) = panic "headFS: Empty FastString"
headFS (FastString _ _ _ buf enc) =
inlinePerformIO $ withForeignPtr buf $ \ptr -> do
case enc of
ZEncoded -> do
......@@ -446,6 +447,7 @@ headFS (FastString _ n_bytes _ buf enc) =
return (fst (utf8DecodeChar ptr))
tailFS :: FastString -> FastString
tailFS (FastString _ 0 _ _ _) = panic "tailFS: Empty FastString"
tailFS (FastString _ n_bytes _ buf enc) =
inlinePerformIO $ withForeignPtr buf $ \ptr -> do
case enc of
......@@ -462,6 +464,7 @@ consFS c fs = mkFastString (c : unpackFS fs)
uniqueOfFS :: FastString -> FastInt
uniqueOfFS (FastString u _ _ _ _) = iUnbox u
nilFS :: FastString
nilFS = mkFastString ""
-- -----------------------------------------------------------------------------
......@@ -478,6 +481,7 @@ getFastStringTable = do
-- |Outputs a 'FastString' with /no decoding at all/, that is, you
-- get the actual bytes in the 'FastString' written to the 'Handle'.
hPutFS :: Handle -> FastString -> IO ()
hPutFS handle (FastString _ len _ fp _)
| len == 0 = return ()
| otherwise = do withForeignPtr fp $ \ptr -> hPutBuf handle ptr len
......@@ -499,8 +503,7 @@ type LitString = Ptr Word8
#if defined(__GLASGOW_HASKELL__)
mkLitString# :: Addr# -> LitString
mkLitString# a# = Ptr a#
#endif
#else
--can/should we use FastTypes here?
--Is this likely to be memory-preserving if only used on constant strings?
--should we inline it? If lucky, that would make a CAF that wouldn't
......@@ -522,6 +525,7 @@ mkLitString s =
loop 0 s
return p
)
#endif
unpackLitString :: LitString -> String
unpackLitString p_ = case pUnbox p_ of
......@@ -562,7 +566,7 @@ foreign import ccall unsafe "ghc_strlen"
pokeCAString :: Ptr CChar -> String -> IO ()
pokeCAString ptr str =
let
go [] n = return ()
go [] _ = return ()
go (c:cs) n = do pokeElemOff ptr n (castCharToCChar c); go cs (n+1)
in
go str 0
......
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