blob: 69d8fb12ea5be703038825785e667aa956d922d3 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
|
%
% (c) The AQUA Project, Glasgow University, 1994-1996
%
\section[PrelArrExtra]{Module @PrelArrExtra@}
The following functions should be in PrelArr, but need -monly-2-regs
to compile. So as not to compile the whole of PrelArr with
-monly-2-regs, the culprits have been moved out into a separate
module.
\begin{code}
{-# OPTIONS -fcompiling-prelude -fno-implicit-prelude #-}
module PrelArrExtra where
import PrelArr
import PrelByteArr
import PrelST
import PrelIOBase
import PrelBase
import PrelGHC
\end{code}
%*********************************************************
%* *
\subsection{Moving between mutable and immutable}
%* *
%*********************************************************
\begin{code}
freezeByteArray :: Ix ix => MutableByteArray s ix -> ST s (ByteArray ix)
{-# SPECIALISE freezeByteArray :: MutableByteArray s Int -> ST s (ByteArray Int) #-}
-- This coercion of memcpy to the ST monad is safe, because memcpy
-- only modifies its destination operand, which is already MutableByteArray.
freezeByteArray (MutableByteArray l u arr) = ST $ \ s ->
let n = sizeofMutableByteArray# arr in
case (newCharArray# n s) of { (# s, newarr #) ->
case ((unsafeCoerce# memcpy) newarr arr n s) of { (# s, () #) ->
case unsafeFreezeByteArray# newarr s of { (# s, frozen #) ->
(# s, ByteArray l u frozen #) }}}
foreign import "memcpy" unsafe
memcpy :: MutableByteArray# RealWorld -> ByteArray# -> Int# -> IO ()
unsafeFreezeByteArray :: Ix ix => MutableByteArray s ix -> ST s (ByteArray ix)
{-# SPECIALIZE unsafeFreezeByteArray :: MutableByteArray s Int -> ST s (ByteArray Int)
#-}
unsafeFreezeByteArray (MutableByteArray l u arr#) = ST $ \ s# ->
case unsafeFreezeByteArray# arr# s# of { (# s2#, frozen# #) ->
(# s2#, ByteArray l u frozen# #) }
\end{code}
|
