[project @ 2005-07-26 12:14:03 by simonmar]

[ghc-hetmet.git] / ghc / compiler / utils / BufWrite.hs

diff --git a/ghc/compiler/utils/BufWrite.hs b/ghc/compiler/utils/BufWrite.hs
new file mode 100644 (file)
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+-----------------------------------------------------------------------------
+--
+-- Fast write-buffered Handles
+--
+-- (c) The University of Glasgow 2005
+--
+-- This is a simple abstraction over Handles that offers very fast write
+-- buffering, but without the thread safety that Handles provide.  It's used
+-- to save time in Pretty.printDoc.
+--
+-----------------------------------------------------------------------------
+
+module BufWrite (
+       BufHandle(..),
+       newBufHandle,
+       bPutChar,
+       bPutStr,
+       bPutFS,
+       bPutLitString,
+       bFlush,
+  ) where
+
+#include "HsVersions.h"
+
+import FastString
+import FastMutInt
+import Panic           ( panic )
+
+import Monad           ( when )
+import Char            ( ord )
+import Foreign
+import IO
+
+#if __GLASGOW_HASKELL__ < 503
+import PrelIOBase      ( IO(..) )
+import IOExts          ( hPutBufFull )
+#else
+import GHC.IOBase      ( IO(..) )
+import System.IO       ( hPutBuf )
+#endif
+
+import GLAEXTS         ( touch#, byteArrayContents#, Int(..), Int#, Addr# )
+
+import PrimPacked      ( Ptr(..) )
+
+-- -----------------------------------------------------------------------------
+
+data BufHandle = BufHandle {-#UNPACK#-}!(Ptr Word8)
+                          {-#UNPACK#-}!FastMutInt
+                          Handle
+
+newBufHandle :: Handle -> IO BufHandle
+newBufHandle hdl = do
+  ptr <- mallocBytes buf_size
+  r <- newFastMutInt
+  writeFastMutInt r 0
+  return (BufHandle ptr r hdl)
+
+buf_size = 8192 :: Int
+
+#define STRICT2(f) f a b | a `seq` b `seq` False = undefined
+#define STRICT3(f) f a b c | a `seq` b `seq` c `seq` False = undefined
+
+bPutChar :: BufHandle -> Char -> IO ()
+STRICT2(bPutChar)
+bPutChar b@(BufHandle buf r hdl) c = do
+  i <- readFastMutInt r
+  if (i >= buf_size)
+       then do hPutBuf hdl buf buf_size
+               writeFastMutInt r 0
+               bPutChar b c
+       else do pokeElemOff buf i (fromIntegral (ord c) :: Word8)
+               writeFastMutInt r (i+1)
+
+bPutStr :: BufHandle -> String -> IO ()
+STRICT2(bPutStr)
+bPutStr b@(BufHandle buf r hdl) str = do
+  i <- readFastMutInt r
+  loop str i
+  where loop _ i | i `seq` False = undefined
+       loop "" i = do writeFastMutInt r i; return ()
+       loop (c:cs) i
+          | i >= buf_size = do
+               hPutBuf hdl buf buf_size
+               loop (c:cs) 0
+          | otherwise = do
+               pokeElemOff buf i (fromIntegral (ord c))
+               loop cs (i+1)
+  
+bPutFS :: BufHandle -> FastString -> IO ()
+bPutFS b@(BufHandle buf r hdl) fs@(FastString _ len# arr#) = do
+  let len = I# len#
+  i <- readFastMutInt r
+  if (i + len) >= buf_size
+       then do hPutBuf hdl buf i
+               writeFastMutInt r 0
+               if (len >= buf_size) 
+                   then do
+                        let a# = byteArrayContents# arr#
+                        hPutBuf hdl (Ptr a#) len
+                        touch fs
+                   else bPutFS b fs
+       else do
+               let a# = byteArrayContents# arr#
+               copyBytes (buf `plusPtr` i) (Ptr a#) len
+               touch fs
+               writeFastMutInt r (i+len)
+bPutFS _ _ = panic "bPutFS"
+
+bPutLitString :: BufHandle -> Addr# -> Int# -> IO ()
+bPutLitString b@(BufHandle buf r hdl) a# len# = do
+  let len = I# len#
+  i <- readFastMutInt r
+  if (i+len) >= buf_size
+       then do hPutBuf hdl buf i
+               writeFastMutInt r 0
+               if (len >= buf_size) 
+                   then hPutBuf hdl (Ptr a#) len
+                   else bPutLitString b a# len#
+       else do
+               copyBytes (buf `plusPtr` i) (Ptr a#) len
+               writeFastMutInt r (i+len)
+
+bFlush :: BufHandle -> IO ()
+bFlush b@(BufHandle buf r hdl) = do
+  i <- readFastMutInt r
+  when (i > 0) $ hPutBuf hdl buf i
+  free buf
+  return ()
+
+touch r = IO $ \s -> case touch# r s of s -> (# s, () #)
+
+#if 0
+myPutBuf s hdl buf i = 
+  modifyIOError (\e -> ioeSetErrorString e (ioeGetErrorString e ++ ':':s ++ " (" ++ show buf ++ "," ++ show i ++ ")")) $
+
+  hPutBuf hdl buf i
+#endif