Files
gf-core/src/runtime/haskell/PGF2/FFI.hsc
2021-08-06 12:43:30 +02:00

104 lines
3.0 KiB
Haskell

{-# LANGUAGE ForeignFunctionInterface, MagicHash, BangPatterns #-}
module PGF2.FFI where
import Data.Word
import Foreign
import Foreign.C
import Foreign.Ptr
import Foreign.ForeignPtr
import qualified Data.Map as Map
#include <pgf.h>
-- | An abstract data type representing multilingual grammar
-- in Portable Grammar Format.
data PGF = PGF {a_pgf :: ForeignPtr PgfPGF, langs :: Map.Map String Concr}
data Concr = Concr {c_pgf :: ForeignPtr PgfPGF, concr :: Ptr PgfConcr}
------------------------------------------------------------------
-- libpgf API
data PgfExn
data PgfText
data PgfItor
data PgfPGF
data PgfConcr
foreign import ccall unsafe "pgf_utf8_decode"
pgf_utf8_decode :: Ptr CString -> IO Word32
foreign import ccall unsafe "pgf_utf8_encode"
pgf_utf8_encode :: Word32 -> Ptr CString -> IO ()
foreign import ccall "pgf_read"
pgf_read :: CString -> Ptr PgfExn -> IO (Ptr PgfPGF)
foreign import ccall "&pgf_free"
pgf_free_fptr :: FinalizerPtr PgfPGF
foreign import ccall "pgf_abstract_name"
pgf_abstract_name :: Ptr PgfPGF -> IO (Ptr PgfText)
type ItorCallback = Ptr PgfItor -> Ptr PgfText -> IO ()
foreign import ccall "wrapper"
wrapItorCallback :: ItorCallback -> IO (FunPtr ItorCallback)
foreign import ccall "pgf_iter_categories"
pgf_iter_categories :: Ptr PgfPGF -> Ptr PgfItor -> IO ()
foreign import ccall "pgf_iter_functions"
pgf_iter_functions :: Ptr PgfPGF -> Ptr PgfItor -> IO ()
foreign import ccall "pgf_iter_functions_by_cat"
pgf_iter_functions_by_cat :: Ptr PgfPGF -> Ptr PgfText -> Ptr PgfItor -> IO ()
peekText :: Ptr PgfText -> IO String
peekText ptr =
alloca $ \pptr -> do
size <- ((#peek PgfText, size) ptr) :: IO CSize
let c_text = castPtr ptr `plusPtr` (#offset PgfText, text)
poke pptr c_text
decode pptr (c_text `plusPtr` fromIntegral size)
where
decode pptr end = do
ptr <- peek pptr
if ptr >= end
then return []
else do x <- pgf_utf8_decode pptr
cs <- decode pptr end
return (((toEnum . fromEnum) x) : cs)
withText :: String -> (Ptr PgfText -> IO a) -> IO a
withText s fn =
allocaBytes ((#size PgfText) + size + 1) $ \ptr -> do
(#poke PgfText, size) ptr (fromIntegral size :: CSize)
pokeUtf8CString s (ptr `plusPtr` (#const offsetof(PgfText, text)))
fn ptr
where
size = utf8Length s
pokeUtf8CString s ptr =
alloca $ \pptr ->
poke pptr ptr >> encode s pptr
where
encode [] pptr = do
pgf_utf8_encode 0 pptr
encode (c:cs) pptr = do
pgf_utf8_encode ((toEnum . fromEnum) c) pptr
encode cs pptr
utf8Length s = count 0 s
where
count !c [] = c
count !c (x:xs)
| ucs < 0x80 = count (c+1) xs
| ucs < 0x800 = count (c+2) xs
| ucs < 0x10000 = count (c+3) xs
| ucs < 0x200000 = count (c+4) xs
| ucs < 0x4000000 = count (c+5) xs
| otherwise = count (c+6) xs
where
ucs = fromEnum x