[Haskell-cafe] Re: Array copying

[Andrew Coppin]

ChrisK wrote:
> For GHC 6.6 I created
>
>   
>> foreign import ccall unsafe "memcpy"
>>     memcpy :: MutableByteArray# RealWorld -> MutableByteArray# RealWorld -> Int# -> IO ()
>>     
>
>   
>> {-# INLINE copySTU #-}
>> copySTU :: (Show i,Ix i,MArray (STUArray s) e (ST s)) => STUArray s i e -> STUArray s i e -> ST s ()
>> copySTU (STUArray _ _ msource) (STUArray _ _ mdest) =
>> -- do b1 <- getBounds s1
>> --  b2 <- getBounds s2
>> --  when (b1/=b2) (error ("\n\nWTF copySTU: "++show (b1,b2)))
>>   ST $ \s1# ->
>>     case sizeofMutableByteArray# msource        of { n# ->
>>     case unsafeCoerce# memcpy mdest msource n# s1# of { (# s2#, () #) ->
>>     (# s2#, () #) }}
>>     
>
> To allow efficient copying of STUArrays.
>   

So... that copies the entire array into another array of the same size? 
(I'm having a lot of trouble understanding the code...)