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{-# language MagicHash #-}
{-# language UnboxedTuples #-}
module CopyArray
( smallCopy
) where
import GHC.Exts
import GHC.IO
data ByteArray = ByteArray ByteArray#
-- Does an 8 byte copy with sub-word (2 bytes) alignment
-- Should be unrolled into 4 aligned stores (MOVWs)
smallCopy :: ByteArray -> IO ByteArray
smallCopy (ByteArray ba) = IO $ \s0 -> case newByteArray# 8# s0 of
(# s1, mut #) -> case copyByteArray# ba 2# mut 0# 8# s1 of
s2 -> case unsafeFreezeByteArray# mut s2 of
(# s3, frozen #) -> (# s3, ByteArray frozen #)
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