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authoraarne <aarne@cs.chalmers.se>2008-06-25 16:54:35 +0000
committeraarne <aarne@cs.chalmers.se>2008-06-25 16:54:35 +0000
commite9e80fc389365e24d4300d7d5390c7d833a96c50 (patch)
treef0b58473adaa670bd8fc52ada419d8cad470ee03 /src/GF/Source/SharedString.hs
parentb96b36f43de3e2f8b58d5f539daa6f6d47f25870 (diff)
changed names of resource-1.3; added a note on homepage on release
Diffstat (limited to 'src/GF/Source/SharedString.hs')
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1 files changed, 20 insertions, 0 deletions
diff --git a/src/GF/Source/SharedString.hs b/src/GF/Source/SharedString.hs
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+module GF.Source.SharedString (shareString) where
+
+import Data.Map as M
+import Data.IORef
+import qualified Data.ByteString.Char8 as BS
+import System.IO.Unsafe (unsafePerformIO)
+
+{-# NOINLINE stringPoolRef #-}
+stringPoolRef :: IORef (M.Map BS.ByteString BS.ByteString)
+stringPoolRef = unsafePerformIO $ newIORef M.empty
+
+{-# NOINLINE shareString #-}
+shareString :: BS.ByteString -> BS.ByteString
+shareString s = unsafePerformIO $ do
+ stringPool <- readIORef stringPoolRef
+ case M.lookup s stringPool of
+ Just s' -> return s'
+ Nothing -> do let s' = BS.copy s
+ writeIORef stringPoolRef $! M.insert s' s' stringPool
+ return s'