Rewrite of the IO library, including Unicode support

[ghc-base.git] / GHC / IOArray.hs

diff --git a/GHC/IOArray.hs b/GHC/IOArray.hs
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+{-# OPTIONS_GHC -fno-implicit-prelude -funbox-strict-fields #-}
+{-# OPTIONS_HADDOCK hide #-}
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  GHC.IOArray
+-- Copyright   :  (c) The University of Glasgow 2008
+-- License     :  see libraries/base/LICENSE
+-- 
+-- Maintainer  :  cvs-ghc@haskell.org
+-- Stability   :  internal
+-- Portability :  non-portable (GHC Extensions)
+--
+-- The IOArray type
+--
+-----------------------------------------------------------------------------
+
+module GHC.IOArray (
+    IOArray(..),
+    newIOArray, unsafeReadIOArray, unsafeWriteIOArray,
+    readIOArray, writeIOArray,
+    boundsIOArray
+  ) where
+
+import GHC.Base
+import GHC.IO
+import GHC.Arr
+
+-- ---------------------------------------------------------------------------
+-- | An 'IOArray' is a mutable, boxed, non-strict array in the 'IO' monad.  
+-- The type arguments are as follows:
+--
+--  * @i@: the index type of the array (should be an instance of 'Ix')
+--
+--  * @e@: the element type of the array.
+--
+-- 
+
+newtype IOArray i e = IOArray (STArray RealWorld i e)
+
+-- explicit instance because Haddock can't figure out a derived one
+instance Eq (IOArray i e) where
+  IOArray x == IOArray y = x == y
+
+-- |Build a new 'IOArray'
+newIOArray :: Ix i => (i,i) -> e -> IO (IOArray i e)
+{-# INLINE newIOArray #-}
+newIOArray lu initial  = stToIO $ do {marr <- newSTArray lu initial; return (IOArray marr)}
+
+-- | Read a value from an 'IOArray'
+unsafeReadIOArray  :: Ix i => IOArray i e -> Int -> IO e
+{-# INLINE unsafeReadIOArray #-}
+unsafeReadIOArray (IOArray marr) i = stToIO (unsafeReadSTArray marr i)
+
+-- | Write a new value into an 'IOArray'
+unsafeWriteIOArray :: Ix i => IOArray i e -> Int -> e -> IO ()
+{-# INLINE unsafeWriteIOArray #-}
+unsafeWriteIOArray (IOArray marr) i e = stToIO (unsafeWriteSTArray marr i e)
+
+-- | Read a value from an 'IOArray'
+readIOArray  :: Ix i => IOArray i e -> i -> IO e
+readIOArray (IOArray marr) i = stToIO (readSTArray marr i)
+
+-- | Write a new value into an 'IOArray'
+writeIOArray :: Ix i => IOArray i e -> i -> e -> IO ()
+writeIOArray (IOArray marr) i e = stToIO (writeSTArray marr i e)
+
+{-# INLINE boundsIOArray #-}
+boundsIOArray :: IOArray i e -> (i,i)  
+boundsIOArray (IOArray marr) = boundsSTArray marr