filepath-1.4.200.0: System/OsPath/Data/ByteString/Short/Internal.hs
{-# LANGUAGE CPP #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE UnboxedTuples #-}
{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE ViewPatterns #-}
{-# LANGUAGE UnliftedFFITypes #-}
-- |
-- Module : System.OsPath.Data.ByteString.Short.Internal
-- Copyright : © 2022 Julian Ospald
-- License : MIT
--
-- Maintainer : Julian Ospald <hasufell@posteo.de>
-- Stability : experimental
-- Portability : portable
--
-- Internal low-level utilities mostly for 'System.OsPath.Data.ByteString.Short.Word16',
-- such as byte-array operations and other stuff not meant to be exported from Word16 module.
module System.OsPath.Data.ByteString.Short.Internal {-# DEPRECATED "Use System.OsString.Data.ByteString.Short.Internal from os-string >= 2.0.0 package instead. This module will be removed in filepath >= 1.5." #-} where
import Control.Monad.ST
import Control.Exception (assert, throwIO)
import Data.Bits (Bits(..))
import Data.ByteString.Short.Internal (ShortByteString(..), length)
#if !MIN_VERSION_base(4,11,0)
import Data.Semigroup
( Semigroup((<>)) )
import Foreign.C.Types
( CSize(..)
, CInt(..)
)
import Data.ByteString.Internal
( accursedUnutterablePerformIO
)
#endif
#if !MIN_VERSION_bytestring(0,10,9)
import Foreign.Marshal.Alloc (allocaBytes)
import Foreign.C.String ( CString, CStringLen )
import Foreign.C.Types ( CSize(..) )
import Foreign.Storable (pokeByteOff)
#endif
import Foreign.Marshal.Array (withArray0, peekArray0, newArray0, withArrayLen, peekArray)
import GHC.Exts
import GHC.Word
import GHC.ST
( ST (ST) )
import GHC.Stack ( HasCallStack )
import Prelude hiding
( length )
import qualified Data.ByteString.Short.Internal as BS
import qualified Data.Char as C
import qualified Data.List as List
_nul :: Word16
_nul = 0x00
isSpace :: Word16 -> Bool
isSpace = C.isSpace . word16ToChar
-- | Total conversion to char.
word16ToChar :: Word16 -> Char
word16ToChar = C.chr . fromIntegral
create :: Int -> (forall s. MBA s -> ST s ()) -> ShortByteString
create len fill =
runST $ do
mba <- newByteArray len
fill mba
BA# ba# <- unsafeFreezeByteArray mba
return (SBS ba#)
{-# INLINE create #-}
asBA :: ShortByteString -> BA
asBA (SBS ba#) = BA# ba#
data BA = BA# ByteArray#
data MBA s = MBA# (MutableByteArray# s)
newPinnedByteArray :: Int -> ST s (MBA s)
newPinnedByteArray (I# len#) =
ST $ \s -> case newPinnedByteArray# len# s of
(# s', mba# #) -> (# s', MBA# mba# #)
newByteArray :: Int -> ST s (MBA s)
newByteArray (I# len#) =
ST $ \s -> case newByteArray# len# s of
(# s', mba# #) -> (# s', MBA# mba# #)
copyByteArray :: BA -> Int -> MBA s -> Int -> Int -> ST s ()
copyByteArray (BA# src#) (I# src_off#) (MBA# dst#) (I# dst_off#) (I# len#) =
ST $ \s -> case copyByteArray# src# src_off# dst# dst_off# len# s of
s' -> (# s', () #)
unsafeFreezeByteArray :: MBA s -> ST s BA
unsafeFreezeByteArray (MBA# mba#) =
ST $ \s -> case unsafeFreezeByteArray# mba# s of
(# s', ba# #) -> (# s', BA# ba# #)
copyAddrToByteArray :: Ptr a -> MBA RealWorld -> Int -> Int -> ST RealWorld ()
copyAddrToByteArray (Ptr src#) (MBA# dst#) (I# dst_off#) (I# len#) =
ST $ \s -> case copyAddrToByteArray# src# dst# dst_off# len# s of
s' -> (# s', () #)
-- this is a copy-paste from bytestring
#if !MIN_VERSION_bytestring(0,10,9)
------------------------------------------------------------------------
-- Primop replacements
-- ---------------------------------------------------------------------
--
-- Standard C functions
--
foreign import ccall unsafe "string.h strlen" c_strlen
:: CString -> IO CSize
-- ---------------------------------------------------------------------
--
-- Uses our C code
--
-- | /O(n)./ Construct a new @ShortByteString@ from a @CString@. The
-- resulting @ShortByteString@ is an immutable copy of the original
-- @CString@, and is managed on the Haskell heap. The original
-- @CString@ must be null terminated.
--
-- @since 0.10.10.0
packCString :: CString -> IO ShortByteString
packCString cstr = do
len <- c_strlen cstr
packCStringLen (cstr, fromIntegral len)
-- | /O(n)./ Construct a new @ShortByteString@ from a @CStringLen@. The
-- resulting @ShortByteString@ is an immutable copy of the original @CStringLen@.
-- The @ShortByteString@ is a normal Haskell value and will be managed on the
-- Haskell heap.
--
-- @since 0.10.10.0
packCStringLen :: CStringLen -> IO ShortByteString
packCStringLen (cstr, len) | len >= 0 = BS.createFromPtr cstr len
packCStringLen (_, len) =
moduleErrorIO "packCStringLen" ("negative length: " ++ show len)
-- | /O(n) construction./ Use a @ShortByteString@ with a function requiring a
-- null-terminated @CString@. The @CString@ is a copy and will be freed
-- automatically; it must not be stored or used after the
-- subcomputation finishes.
--
-- @since 0.10.10.0
useAsCString :: ShortByteString -> (CString -> IO a) -> IO a
useAsCString bs action =
allocaBytes (l+1) $ \buf -> do
BS.copyToPtr bs 0 buf (fromIntegral l)
pokeByteOff buf l (0::Word8)
action buf
where l = length bs
-- | /O(n) construction./ Use a @ShortByteString@ with a function requiring a 'CStringLen'.
-- As for 'useAsCString' this function makes a copy of the original @ShortByteString@.
-- It must not be stored or used after the subcomputation finishes.
--
-- Beware that this function does not add a terminating @\NUL@ byte at the end of 'CStringLen'.
-- If you need to construct a pointer to a null-terminated sequence, use 'useAsCString'
-- (and measure length independently if desired).
--
-- @since 0.10.10.0
useAsCStringLen :: ShortByteString -> (CStringLen -> IO a) -> IO a
useAsCStringLen bs action =
allocaBytes l $ \buf -> do
BS.copyToPtr bs 0 buf (fromIntegral l)
action (buf, l)
where l = length bs
#endif
-- | /O(n)./ Construct a new @ShortByteString@ from a @CWString@. The
-- resulting @ShortByteString@ is an immutable copy of the original
-- @CWString@, and is managed on the Haskell heap. The original
-- @CWString@ must be null terminated.
--
-- @since 0.10.10.0
packCWString :: Ptr Word16 -> IO ShortByteString
packCWString cwstr = do
cs <- peekArray0 _nul cwstr
return (packWord16 cs)
-- | /O(n)./ Construct a new @ShortByteString@ from a @CWStringLen@. The
-- resulting @ShortByteString@ is an immutable copy of the original @CWStringLen@.
-- The @ShortByteString@ is a normal Haskell value and will be managed on the
-- Haskell heap.
--
-- @since 0.10.10.0
packCWStringLen :: (Ptr Word16, Int) -> IO ShortByteString
packCWStringLen (cp, len) = do
cs <- peekArray len cp
return (packWord16 cs)
-- | /O(n) construction./ Use a @ShortByteString@ with a function requiring a
-- null-terminated @CWString@. The @CWString@ is a copy and will be freed
-- automatically; it must not be stored or used after the
-- subcomputation finishes.
--
-- @since 0.10.10.0
useAsCWString :: ShortByteString -> (Ptr Word16 -> IO a) -> IO a
useAsCWString = withArray0 _nul . unpackWord16
-- | /O(n) construction./ Use a @ShortByteString@ with a function requiring a @CWStringLen@.
-- As for @useAsCWString@ this function makes a copy of the original @ShortByteString@.
-- It must not be stored or used after the subcomputation finishes.
--
-- @since 0.10.10.0
useAsCWStringLen :: ShortByteString -> ((Ptr Word16, Int) -> IO a) -> IO a
useAsCWStringLen bs action = withArrayLen (unpackWord16 bs) $ \ len ptr -> action (ptr, len)
-- | /O(n) construction./ Use a @ShortByteString@ with a function requiring a @CWStringLen@.
-- As for @useAsCWString@ this function makes a copy of the original @ShortByteString@.
-- It must not be stored or used after the subcomputation finishes.
--
-- @since 0.10.10.0
newCWString :: ShortByteString -> IO (Ptr Word16)
newCWString = newArray0 _nul . unpackWord16
-- ---------------------------------------------------------------------
-- Internal utilities
moduleErrorIO :: String -> String -> IO a
moduleErrorIO fun msg = throwIO . userError $ moduleErrorMsg fun msg
{-# NOINLINE moduleErrorIO #-}
moduleErrorMsg :: String -> String -> String
moduleErrorMsg fun msg = "System.OsPath.Data.ByteString.Short." ++ fun ++ ':':' ':msg
packWord16 :: [Word16] -> ShortByteString
packWord16 cs = packLenWord16 (List.length cs) cs
packLenWord16 :: Int -> [Word16] -> ShortByteString
packLenWord16 len ws0 =
create (len * 2) (\mba -> go mba 0 ws0)
where
go :: MBA s -> Int -> [Word16] -> ST s ()
go !_ !_ [] = return ()
go !mba !i (w:ws) = do
writeWord16Array mba i w
go mba (i+2) ws
unpackWord16 :: ShortByteString -> [Word16]
unpackWord16 sbs = go len []
where
len = length sbs
go !i !acc
| i < 1 = acc
| otherwise = let !w = indexWord16Array (asBA sbs) (i - 2)
in go (i - 2) (w:acc)
packWord16Rev :: [Word16] -> ShortByteString
packWord16Rev cs = packLenWord16Rev (List.length cs * 2) cs
packLenWord16Rev :: Int -> [Word16] -> ShortByteString
packLenWord16Rev len ws0 =
create len (\mba -> go mba len ws0)
where
go :: MBA s -> Int -> [Word16] -> ST s ()
go !_ !_ [] = return ()
go !mba !i (w:ws) = do
writeWord16Array mba (i - 2) w
go mba (i - 2) ws
-- | This isn't strictly Word16 array write. Instead it's two consecutive Word8 array
-- writes to avoid endianness issues due to primops doing automatic alignment based
-- on host platform. We want to always write LE to the byte array.
writeWord16Array :: MBA s
-> Int -- ^ Word8 index (not Word16)
-> Word16
-> ST s ()
writeWord16Array (MBA# mba#) (I# i#) (W16# w#) =
case encodeWord16LE# w# of
(# lsb#, msb# #) ->
ST (\s -> case writeWord8Array# mba# i# lsb# s of
s' -> (# s', () #)) >>
ST (\s -> case writeWord8Array# mba# (i# +# 1#) msb# s of
s' -> (# s', () #))
indexWord8Array :: BA
-> Int -- ^ Word8 index
-> Word8
indexWord8Array (BA# ba#) (I# i#) = W8# (indexWord8Array# ba# i#)
-- | This isn't strictly Word16 array read. Instead it's two Word8 array reads
-- to avoid endianness issues due to primops doing automatic alignment based
-- on host platform. We expect the byte array to be LE always.
indexWord16Array :: BA
-> Int -- ^ Word8 index (not Word16)
-> Word16
indexWord16Array ba i = fromIntegral lsb .|. (fromIntegral msb `shiftL` 8)
where
lsb = indexWord8Array ba i
msb = indexWord8Array ba (i + 1)
#if !MIN_VERSION_base(4,16,0)
encodeWord16LE# :: Word# -- ^ Word16
-> (# Word#, Word# #) -- ^ Word8 (LSB, MSB)
encodeWord16LE# x# = (# x# `and#` int2Word# 0xff#
, x# `and#` int2Word# 0xff00# `shiftRL#` 8# #)
decodeWord16LE# :: (# Word#, Word# #) -- ^ Word8 (LSB, MSB)
-> Word# -- ^ Word16
decodeWord16LE# (# lsb#, msb# #) = msb# `shiftL#` 8# `or#` lsb#
#else
encodeWord16LE# :: Word16# -- ^ Word16
-> (# Word8#, Word8# #) -- ^ Word8 (LSB, MSB)
encodeWord16LE# x# = (# word16ToWord8# x#
, word16ToWord8# (x# `uncheckedShiftRLWord16#` 8#) #)
where
word16ToWord8# y = wordToWord8# (word16ToWord# y)
decodeWord16LE# :: (# Word8#, Word8# #) -- ^ Word8 (LSB, MSB)
-> Word16# -- ^ Word16
decodeWord16LE# (# lsb#, msb# #) = ((word8ToWord16# msb# `uncheckedShiftLWord16#` 8#) `orWord16#` word8ToWord16# lsb#)
where
word8ToWord16# y = wordToWord16# (word8ToWord# y)
#endif
setByteArray :: MBA s -> Int -> Int -> Int -> ST s ()
setByteArray (MBA# dst#) (I# off#) (I# len#) (I# c#) =
ST $ \s -> case setByteArray# dst# off# len# c# s of
s' -> (# s', () #)
copyMutableByteArray :: MBA s -> Int -> MBA s -> Int -> Int -> ST s ()
copyMutableByteArray (MBA# src#) (I# src_off#) (MBA# dst#) (I# dst_off#) (I# len#) =
ST $ \s -> case copyMutableByteArray# src# src_off# dst# dst_off# len# s of
s' -> (# s', () #)
-- | Given the maximum size needed and a function to make the contents
-- of a ShortByteString, createAndTrim makes the 'ShortByteString'.
-- The generating function is required to return the actual final size
-- (<= the maximum size) and the result value. The resulting byte array
-- is realloced to this size.
createAndTrim :: Int -> (forall s. MBA s -> ST s (Int, a)) -> (ShortByteString, a)
createAndTrim l fill =
runST $ do
mba <- newByteArray l
(l', res) <- fill mba
if assert (l' <= l) $ l' >= l
then do
BA# ba# <- unsafeFreezeByteArray mba
return (SBS ba#, res)
else do
mba2 <- newByteArray l'
copyMutableByteArray mba 0 mba2 0 l'
BA# ba# <- unsafeFreezeByteArray mba2
return (SBS ba#, res)
{-# INLINE createAndTrim #-}
createAndTrim' :: Int -> (forall s. MBA s -> ST s Int) -> ShortByteString
createAndTrim' l fill =
runST $ do
mba <- newByteArray l
l' <- fill mba
if assert (l' <= l) $ l' >= l
then do
BA# ba# <- unsafeFreezeByteArray mba
return (SBS ba#)
else do
mba2 <- newByteArray l'
copyMutableByteArray mba 0 mba2 0 l'
BA# ba# <- unsafeFreezeByteArray mba2
return (SBS ba#)
{-# INLINE createAndTrim' #-}
createAndTrim'' :: Int -> (forall s. MBA s -> MBA s -> ST s (Int, Int)) -> (ShortByteString, ShortByteString)
createAndTrim'' l fill =
runST $ do
mba1 <- newByteArray l
mba2 <- newByteArray l
(l1, l2) <- fill mba1 mba2
sbs1 <- freeze' l1 mba1
sbs2 <- freeze' l2 mba2
pure (sbs1, sbs2)
where
freeze' :: Int -> MBA s -> ST s ShortByteString
freeze' l' mba =
if assert (l' <= l) $ l' >= l
then do
BA# ba# <- unsafeFreezeByteArray mba
return (SBS ba#)
else do
mba2 <- newByteArray l'
copyMutableByteArray mba 0 mba2 0 l'
BA# ba# <- unsafeFreezeByteArray mba2
return (SBS ba#)
{-# INLINE createAndTrim'' #-}
-- Returns the index of the first match or the length of the whole
-- bytestring if nothing matched.
findIndexOrLength :: (Word16 -> Bool) -> ShortByteString -> Int
findIndexOrLength k (assertEven -> sbs) = go 0
where
l = BS.length sbs
ba = asBA sbs
w = indexWord16Array ba
go !n | n >= l = l `div` 2
| k (w n) = n `div` 2
| otherwise = go (n + 2)
{-# INLINE findIndexOrLength #-}
-- | Returns the length of the substring matching, not the index.
-- If no match, returns 0.
findFromEndUntil :: (Word16 -> Bool) -> ShortByteString -> Int
findFromEndUntil k sbs = go (BS.length sbs - 2)
where
ba = asBA sbs
w = indexWord16Array ba
go !n | n < 0 = 0
| k (w n) = (n `div` 2) + 1
| otherwise = go (n - 2)
{-# INLINE findFromEndUntil #-}
assertEven :: ShortByteString -> ShortByteString
assertEven sbs@(SBS barr#)
| even (I# (sizeofByteArray# barr#)) = sbs
| otherwise = error ("Uneven number of bytes: " <> show (BS.length sbs) <> ". This is not a Word16 bytestream.")
-- Common up near identical calls to `error' to reduce the number
-- constant strings created when compiled:
errorEmptySBS :: HasCallStack => String -> a
errorEmptySBS fun = moduleError fun "empty ShortByteString"
{-# NOINLINE errorEmptySBS #-}
moduleError :: HasCallStack => String -> String -> a
moduleError fun msg = error (moduleErrorMsg fun msg)
{-# NOINLINE moduleError #-}
compareByteArraysOff :: BA -- ^ array 1
-> Int -- ^ offset for array 1
-> BA -- ^ array 2
-> Int -- ^ offset for array 2
-> Int -- ^ length to compare
-> Int -- ^ like memcmp
#if MIN_VERSION_base(4,11,0)
compareByteArraysOff (BA# ba1#) (I# ba1off#) (BA# ba2#) (I# ba2off#) (I# len#) =
I# (compareByteArrays# ba1# ba1off# ba2# ba2off# len#)
#else
compareByteArraysOff (BA# ba1#) ba1off (BA# ba2#) ba2off len =
assert (ba1off + len <= (I# (sizeofByteArray# ba1#)))
$ assert (ba2off + len <= (I# (sizeofByteArray# ba2#)))
$ fromIntegral $ accursedUnutterablePerformIO $
c_memcmp_ByteArray ba1#
ba1off
ba2#
ba2off
(fromIntegral len)
foreign import ccall unsafe "static sbs_memcmp_off"
c_memcmp_ByteArray :: ByteArray# -> Int -> ByteArray# -> Int -> CSize -> IO CInt
#endif