{-# LANGUAGE CPP, GeneralizedNewtypeDeriving, MagicHash #-}
-- |
-- Module      : Data.Text.Foreign
-- Copyright   : (c) 2009, 2010 Bryan O'Sullivan
--
-- License     : BSD-style
-- Maintainer  : bos@serpentine.com
-- Portability : GHC
--
-- Support for using 'Text' data with native code via the Haskell
-- foreign function interface.

module Data.Text.Foreign
    (
    -- * Interoperability with native code
    -- $interop
      I8
    -- * Safe conversion functions
    , fromPtr
    , fromPtr0
    , useAsPtr
    , asForeignPtr
    -- ** Encoding as UTF-8
    , withCString
    , peekCStringLen
    , withCStringLen
    -- * Unsafe conversion code
    , lengthWord8
    , unsafeCopyToPtr
    -- * Low-level manipulation
    -- $lowlevel
    , dropWord8
    , takeWord8
    ) where

import Control.Monad.ST.Unsafe (unsafeSTToIO)
import Data.ByteString.Unsafe (unsafePackCStringLen, unsafeUseAsCStringLen)
import Data.Text.Encoding (decodeUtf8, encodeUtf8)
import Data.Text.Internal (Text(..), empty)
import Data.Text.Internal.Unsafe (unsafeWithForeignPtr)
import Data.Text.Show (addrLen)
import Data.Text.Unsafe (lengthWord8)
import Data.Word (Word8)
import Foreign.C.String (CString, CStringLen)
import Foreign.ForeignPtr (ForeignPtr, mallocForeignPtrArray)
import Foreign.Marshal.Alloc (allocaBytes)
import Foreign.Ptr (Ptr, castPtr)
import Foreign.Storable (pokeByteOff)
import GHC.Exts (Ptr(..))
import qualified Data.Text.Array as A

-- $interop
--
-- The 'Text' type is implemented using arrays that are not guaranteed
-- to have a fixed address in the Haskell heap. All communication with
-- native code must thus occur by copying data back and forth.
--
-- The 'Text' type's internal representation is UTF-8.
-- To interoperate with native libraries that use different
-- internal representations, such as UTF-16 or UTF-32, consider using
-- the functions in the 'Data.Text.Encoding' module.

-- | A type representing a number of UTF-8 code units.
--
-- @since 2.0
newtype I8 = I8 Int
    deriving (I8
forall a. a -> a -> Bounded a
maxBound :: I8
$cmaxBound :: I8
minBound :: I8
$cminBound :: I8
Bounded, Int -> I8
I8 -> Int
I8 -> [I8]
I8 -> I8
I8 -> I8 -> [I8]
I8 -> I8 -> I8 -> [I8]
forall a.
(a -> a)
-> (a -> a)
-> (Int -> a)
-> (a -> Int)
-> (a -> [a])
-> (a -> a -> [a])
-> (a -> a -> [a])
-> (a -> a -> a -> [a])
-> Enum a
enumFromThenTo :: I8 -> I8 -> I8 -> [I8]
$cenumFromThenTo :: I8 -> I8 -> I8 -> [I8]
enumFromTo :: I8 -> I8 -> [I8]
$cenumFromTo :: I8 -> I8 -> [I8]
enumFromThen :: I8 -> I8 -> [I8]
$cenumFromThen :: I8 -> I8 -> [I8]
enumFrom :: I8 -> [I8]
$cenumFrom :: I8 -> [I8]
fromEnum :: I8 -> Int
$cfromEnum :: I8 -> Int
toEnum :: Int -> I8
$ctoEnum :: Int -> I8
pred :: I8 -> I8
$cpred :: I8 -> I8
succ :: I8 -> I8
$csucc :: I8 -> I8
Enum, I8 -> I8 -> Bool
forall a. (a -> a -> Bool) -> (a -> a -> Bool) -> Eq a
/= :: I8 -> I8 -> Bool
$c/= :: I8 -> I8 -> Bool
== :: I8 -> I8 -> Bool
$c== :: I8 -> I8 -> Bool
Eq, Enum I8
Real I8
I8 -> Integer
I8 -> I8 -> (I8, I8)
I8 -> I8 -> I8
forall a.
Real a
-> Enum a
-> (a -> a -> a)
-> (a -> a -> a)
-> (a -> a -> a)
-> (a -> a -> a)
-> (a -> a -> (a, a))
-> (a -> a -> (a, a))
-> (a -> Integer)
-> Integral a
toInteger :: I8 -> Integer
$ctoInteger :: I8 -> Integer
divMod :: I8 -> I8 -> (I8, I8)
$cdivMod :: I8 -> I8 -> (I8, I8)
quotRem :: I8 -> I8 -> (I8, I8)
$cquotRem :: I8 -> I8 -> (I8, I8)
mod :: I8 -> I8 -> I8
$cmod :: I8 -> I8 -> I8
div :: I8 -> I8 -> I8
$cdiv :: I8 -> I8 -> I8
rem :: I8 -> I8 -> I8
$crem :: I8 -> I8 -> I8
quot :: I8 -> I8 -> I8
$cquot :: I8 -> I8 -> I8
Integral, Integer -> I8
I8 -> I8
I8 -> I8 -> I8
forall a.
(a -> a -> a)
-> (a -> a -> a)
-> (a -> a -> a)
-> (a -> a)
-> (a -> a)
-> (a -> a)
-> (Integer -> a)
-> Num a
fromInteger :: Integer -> I8
$cfromInteger :: Integer -> I8
signum :: I8 -> I8
$csignum :: I8 -> I8
abs :: I8 -> I8
$cabs :: I8 -> I8
negate :: I8 -> I8
$cnegate :: I8 -> I8
* :: I8 -> I8 -> I8
$c* :: I8 -> I8 -> I8
- :: I8 -> I8 -> I8
$c- :: I8 -> I8 -> I8
+ :: I8 -> I8 -> I8
$c+ :: I8 -> I8 -> I8
Num, Eq I8
I8 -> I8 -> Bool
I8 -> I8 -> Ordering
I8 -> I8 -> I8
forall a.
Eq a
-> (a -> a -> Ordering)
-> (a -> a -> Bool)
-> (a -> a -> Bool)
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-> (a -> a -> Bool)
-> (a -> a -> a)
-> (a -> a -> a)
-> Ord a
min :: I8 -> I8 -> I8
$cmin :: I8 -> I8 -> I8
max :: I8 -> I8 -> I8
$cmax :: I8 -> I8 -> I8
>= :: I8 -> I8 -> Bool
$c>= :: I8 -> I8 -> Bool
> :: I8 -> I8 -> Bool
$c> :: I8 -> I8 -> Bool
<= :: I8 -> I8 -> Bool
$c<= :: I8 -> I8 -> Bool
< :: I8 -> I8 -> Bool
$c< :: I8 -> I8 -> Bool
compare :: I8 -> I8 -> Ordering
$ccompare :: I8 -> I8 -> Ordering
Ord, ReadPrec [I8]
ReadPrec I8
Int -> ReadS I8
ReadS [I8]
forall a.
(Int -> ReadS a)
-> ReadS [a] -> ReadPrec a -> ReadPrec [a] -> Read a
readListPrec :: ReadPrec [I8]
$creadListPrec :: ReadPrec [I8]
readPrec :: ReadPrec I8
$creadPrec :: ReadPrec I8
readList :: ReadS [I8]
$creadList :: ReadS [I8]
readsPrec :: Int -> ReadS I8
$creadsPrec :: Int -> ReadS I8
Read, Num I8
Ord I8
I8 -> Rational
forall a. Num a -> Ord a -> (a -> Rational) -> Real a
toRational :: I8 -> Rational
$ctoRational :: I8 -> Rational
Real, Int -> I8 -> ShowS
[I8] -> ShowS
I8 -> String
forall a.
(Int -> a -> ShowS) -> (a -> String) -> ([a] -> ShowS) -> Show a
showList :: [I8] -> ShowS
$cshowList :: [I8] -> ShowS
show :: I8 -> String
$cshow :: I8 -> String
showsPrec :: Int -> I8 -> ShowS
$cshowsPrec :: Int -> I8 -> ShowS
Show)

-- | /O(n)/ Create a new 'Text' from a 'Ptr' 'Word8' by copying the
-- contents of the array.
fromPtr :: Ptr Word8           -- ^ source array
        -> I8                  -- ^ length of source array (in 'Word8' units)
        -> IO Text
fromPtr :: Ptr Word8 -> I8 -> IO Text
fromPtr Ptr Word8
ptr (I8 Int
len) = forall s a. ST s a -> IO a
unsafeSTToIO forall a b. (a -> b) -> a -> b
$ do
  MArray Any
dst <- forall s. Int -> ST s (MArray s)
A.new Int
len
  forall s. MArray s -> Int -> Ptr Word8 -> Int -> ST s ()
A.copyFromPointer MArray Any
dst Int
0 Ptr Word8
ptr Int
len
  Array
arr <- forall s. MArray s -> ST s Array
A.unsafeFreeze MArray Any
dst
  forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$! Array -> Int -> Int -> Text
Text Array
arr Int
0 Int
len

-- | /O(n)/ Create a new 'Text' from a 'Ptr' 'Word8' by copying the
-- contents of the NUL-terminated array.
--
-- @since 2.0.1
fromPtr0 :: Ptr Word8           -- ^ source array
         -> IO Text
fromPtr0 :: Ptr Word8 -> IO Text
fromPtr0 ptr :: Ptr Word8
ptr@(Ptr Addr#
addr#) = Ptr Word8 -> I8 -> IO Text
fromPtr Ptr Word8
ptr (forall a b. (Integral a, Num b) => a -> b
fromIntegral (Addr# -> Int
addrLen Addr#
addr#))

-- $lowlevel
--
-- Foreign functions that use UTF-8 internally may return indices in
-- units of 'Word8' instead of characters.  These functions may
-- safely be used with such indices, as they will adjust offsets if
-- necessary to preserve the validity of a Unicode string.

-- | /O(1)/ Return the prefix of the 'Text' of @n@ 'Word8' units in
-- length.
--
-- If @n@ would cause the 'Text' to end inside a code point, the
-- end of the prefix will be advanced by several additional 'Word8' units
-- to maintain its validity.
--
-- @since 2.0
takeWord8 :: I8 -> Text -> Text
takeWord8 :: I8 -> Text -> Text
takeWord8 = (forall a b. (a, b) -> a
fst forall b c a. (b -> c) -> (a -> b) -> a -> c
.) forall b c a. (b -> c) -> (a -> b) -> a -> c
. I8 -> Text -> (Text, Text)
splitAtWord8

-- | /O(1)/ Return the suffix of the 'Text', with @n@ 'Word8' units
-- dropped from its beginning.
--
-- If @n@ would cause the 'Text' to begin inside a code point, the
-- beginning of the suffix will be advanced by several additional 'Word8'
-- unit to maintain its validity.
--
-- @since 2.0
dropWord8 :: I8 -> Text -> Text
dropWord8 :: I8 -> Text -> Text
dropWord8 = (forall a b. (a, b) -> b
snd forall b c a. (b -> c) -> (a -> b) -> a -> c
.) forall b c a. (b -> c) -> (a -> b) -> a -> c
. I8 -> Text -> (Text, Text)
splitAtWord8

splitAtWord8 :: I8 -> Text -> (Text, Text)
splitAtWord8 :: I8 -> Text -> (Text, Text)
splitAtWord8 (I8 Int
n) t :: Text
t@(Text Array
arr Int
off Int
len)
    | Int
n forall a. Ord a => a -> a -> Bool
<= Int
0               = (Text
empty, Text
t)
    | Int
n forall a. Ord a => a -> a -> Bool
>= Int
len Bool -> Bool -> Bool
|| Int
m forall a. Ord a => a -> a -> Bool
>= Int
len = (Text
t, Text
empty)
    | Bool
otherwise            = (Array -> Int -> Int -> Text
Text Array
arr Int
off Int
m, Array -> Int -> Int -> Text
Text Array
arr (Int
offforall a. Num a => a -> a -> a
+Int
m) (Int
lenforall a. Num a => a -> a -> a
-Int
m))
  where
    m :: Int
m | Word8
w0 forall a. Ord a => a -> a -> Bool
<  Word8
0x80 = Int
n   -- last char is ASCII
      | Word8
w0 forall a. Ord a => a -> a -> Bool
>= Word8
0xF0 = Int
nforall a. Num a => a -> a -> a
+Int
3 -- last char starts 4-byte sequence
      | Word8
w0 forall a. Ord a => a -> a -> Bool
>= Word8
0xE0 = Int
nforall a. Num a => a -> a -> a
+Int
2 -- last char starts 3-byte sequence
      | Word8
w0 forall a. Ord a => a -> a -> Bool
>= Word8
0xC0 = Int
nforall a. Num a => a -> a -> a
+Int
1 -- last char starts 2-byte sequence
      | Word8
w1 forall a. Ord a => a -> a -> Bool
>= Word8
0xF0 = Int
nforall a. Num a => a -> a -> a
+Int
2 -- pre-last char starts 4-byte sequence
      | Word8
w1 forall a. Ord a => a -> a -> Bool
>= Word8
0xE0 = Int
nforall a. Num a => a -> a -> a
+Int
1 -- pre-last char starts 3-byte sequence
      | Word8
w1 forall a. Ord a => a -> a -> Bool
>= Word8
0xC0 = Int
n   -- pre-last char starts 2-byte sequence
      | Word8
w2 forall a. Ord a => a -> a -> Bool
>= Word8
0xF0 = Int
nforall a. Num a => a -> a -> a
+Int
1 -- pre-pre-last char starts 4-byte sequence
      | Bool
otherwise  = Int
n   -- pre-pre-last char starts 3-byte sequence
    w0 :: Word8
w0 = Array -> Int -> Word8
A.unsafeIndex Array
arr (Int
offforall a. Num a => a -> a -> a
+Int
nforall a. Num a => a -> a -> a
-Int
1)
    w1 :: Word8
w1 = Array -> Int -> Word8
A.unsafeIndex Array
arr (Int
offforall a. Num a => a -> a -> a
+Int
nforall a. Num a => a -> a -> a
-Int
2)
    w2 :: Word8
w2 = Array -> Int -> Word8
A.unsafeIndex Array
arr (Int
offforall a. Num a => a -> a -> a
+Int
nforall a. Num a => a -> a -> a
-Int
3)

-- | /O(n)/ Copy a 'Text' to an array.  The array is assumed to be big
-- enough to hold the contents of the entire 'Text'.
unsafeCopyToPtr :: Text -> Ptr Word8 -> IO ()
unsafeCopyToPtr :: Text -> Ptr Word8 -> IO ()
unsafeCopyToPtr (Text Array
arr Int
off Int
len) Ptr Word8
ptr = forall s a. ST s a -> IO a
unsafeSTToIO forall a b. (a -> b) -> a -> b
$ forall s. Array -> Int -> Ptr Word8 -> Int -> ST s ()
A.copyToPointer Array
arr Int
off Ptr Word8
ptr Int
len

-- | /O(n)/ Perform an action on a temporary, mutable copy of a
-- 'Text'.  The copy is freed as soon as the action returns.
useAsPtr :: Text -> (Ptr Word8 -> I8 -> IO a) -> IO a
useAsPtr :: forall a. Text -> (Ptr Word8 -> I8 -> IO a) -> IO a
useAsPtr t :: Text
t@(Text Array
_arr Int
_off Int
len) Ptr Word8 -> I8 -> IO a
action =
    forall a b. Int -> (Ptr a -> IO b) -> IO b
allocaBytes Int
len forall a b. (a -> b) -> a -> b
$ \Ptr Word8
buf -> do
      Text -> Ptr Word8 -> IO ()
unsafeCopyToPtr Text
t Ptr Word8
buf
      Ptr Word8 -> I8 -> IO a
action (forall a b. Ptr a -> Ptr b
castPtr Ptr Word8
buf) (Int -> I8
I8 Int
len)

-- | /O(n)/ Make a mutable copy of a 'Text'.
asForeignPtr :: Text -> IO (ForeignPtr Word8, I8)
asForeignPtr :: Text -> IO (ForeignPtr Word8, I8)
asForeignPtr t :: Text
t@(Text Array
_arr Int
_off Int
len) = do
  ForeignPtr Word8
fp <- forall a. Storable a => Int -> IO (ForeignPtr a)
mallocForeignPtrArray Int
len
  forall a b. ForeignPtr a -> (Ptr a -> IO b) -> IO b
unsafeWithForeignPtr ForeignPtr Word8
fp forall a b. (a -> b) -> a -> b
$ Text -> Ptr Word8 -> IO ()
unsafeCopyToPtr Text
t
  forall (m :: * -> *) a. Monad m => a -> m a
return (ForeignPtr Word8
fp, Int -> I8
I8 Int
len)

-- | Marshal a 'Text' into a C string with a trailing NUL byte,
-- encoded as UTF-8 in temporary storage.
--
-- The temporary storage is freed when the subcomputation terminates
-- (either normally or via an exception), so the pointer to the
-- temporary storage must /not/ be used after this function returns.
--
-- @since 2.0.1
withCString :: Text -> (CString -> IO a) -> IO a
withCString :: forall a. Text -> (CString -> IO a) -> IO a
withCString t :: Text
t@(Text Array
_arr Int
_off Int
len) CString -> IO a
action =
  forall a b. Int -> (Ptr a -> IO b) -> IO b
allocaBytes (Int
len forall a. Num a => a -> a -> a
+ Int
1) forall a b. (a -> b) -> a -> b
$ \Ptr Word8
buf -> do
    Text -> Ptr Word8 -> IO ()
unsafeCopyToPtr Text
t Ptr Word8
buf
    forall a b. Storable a => Ptr b -> Int -> a -> IO ()
pokeByteOff Ptr Word8
buf Int
len (Word8
0 :: Word8)
    CString -> IO a
action (forall a b. Ptr a -> Ptr b
castPtr Ptr Word8
buf)

-- | /O(n)/ Decode a C string with explicit length, which is assumed
-- to have been encoded as UTF-8. If decoding fails, a
-- 'UnicodeException' is thrown.
--
-- @since 1.0.0.0
peekCStringLen :: CStringLen -> IO Text
peekCStringLen :: CStringLen -> IO Text
peekCStringLen CStringLen
cs = do
  ByteString
bs <- CStringLen -> IO ByteString
unsafePackCStringLen CStringLen
cs
  forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$! ByteString -> Text
decodeUtf8 ByteString
bs

-- | Marshal a 'Text' into a C string encoded as UTF-8 in temporary
-- storage, with explicit length information. The encoded string may
-- contain NUL bytes, and is not followed by a trailing NUL byte.
--
-- The temporary storage is freed when the subcomputation terminates
-- (either normally or via an exception), so the pointer to the
-- temporary storage must /not/ be used after this function returns.
--
-- @since 1.0.0.0
withCStringLen :: Text -> (CStringLen -> IO a) -> IO a
withCStringLen :: forall a. Text -> (CStringLen -> IO a) -> IO a
withCStringLen Text
t CStringLen -> IO a
act = forall a. ByteString -> (CStringLen -> IO a) -> IO a
unsafeUseAsCStringLen (Text -> ByteString
encodeUtf8 Text
t) CStringLen -> IO a
act