-- | Arguments and return types
module Foreign.LibFFI.Types (
    -- * Arguments
    -- ** Integral types
    argCInt,
    argCUInt,
    argCLong,
    argCULong,
    argInt,
    argInt8,
    argInt16,
    argInt32,
    argInt64,
    argWord,
    argWord8,
    argWord16,
    argWord32,
    argWord64,
    -- ** Floating point types
    argCFloat,
    argCDouble,
    -- ** Various other C types
    argCSize,
    argCTime,
    argCChar,
    argCUChar,
    argCWchar,
    argPtr,
    argFunPtr,
    -- ** Strings
    argString,
    argByteString,
    argConstByteString,
    -- * Return types
    -- ** Integral types
    retVoid,
    retCInt,
    retCUInt,
    retCLong,
    retCULong,
    retInt,
    retInt8,
    retInt16,
    retInt32,
    retInt64,
    retWord,
    retWord8,
    retWord16,
    retWord32,
    retWord64,
    -- ** Floating point types
    retCFloat,
    retCDouble,
    -- ** Various other C types
    retCSize,
    retCTime,
    retCChar,
    retCUChar,
    retCWchar,
    retPtr,
    retFunPtr,
    -- ** Strings
    retCString,
    retString,
    retByteString,
    retMallocByteString
    ) where

import           Data.Int
import           Data.Word

import qualified Data.ByteString         as BS
import qualified Data.ByteString.Unsafe  as BSU
import           Foreign.C.String
import           Foreign.C.Types
import           Foreign.Marshal
import           Foreign.Ptr

import           Foreign.LibFFI.Base
import           Foreign.LibFFI.FFITypes

argCInt     :: CInt -> Arg
argCInt     = mkStorableArg ffi_type_sint
argCUInt    :: CUInt -> Arg
argCUInt    = mkStorableArg ffi_type_uint
argCLong    :: CLong -> Arg
argCLong    = mkStorableArg ffi_type_slong
argCULong   :: CULong -> Arg
argCULong   = mkStorableArg ffi_type_ulong

-- | Note that on e.g. x86_64, Int \/= CInt
argInt      :: Int -> Arg
argInt      = mkStorableArg ffi_type_hs_int
argInt8     :: Int8 -> Arg
argInt8     = mkStorableArg ffi_type_sint8
argInt16    :: Int16 -> Arg
argInt16    = mkStorableArg ffi_type_sint16
argInt32    :: Int32 -> Arg
argInt32    = mkStorableArg ffi_type_sint32
argInt64    :: Int64 -> Arg
argInt64    = mkStorableArg ffi_type_sint64

argWord     :: Word -> Arg
argWord     = mkStorableArg ffi_type_hs_word
argWord8    :: Word8 -> Arg
argWord8    = mkStorableArg ffi_type_uint8
argWord16   :: Word16 -> Arg
argWord16   = mkStorableArg ffi_type_uint16
argWord32   :: Word32 -> Arg
argWord32   = mkStorableArg ffi_type_uint32
argWord64   :: Word64 -> Arg
argWord64   = mkStorableArg ffi_type_uint64

argCFloat   :: CFloat -> Arg
argCFloat   = mkStorableArg ffi_type_float
argCDouble  :: CDouble -> Arg
argCDouble  = mkStorableArg ffi_type_double

argCSize    :: CSize -> Arg
argCSize    = mkStorableArg ffi_type_size
argCTime    :: CTime -> Arg
argCTime    = mkStorableArg ffi_type_size

argCChar    :: CChar -> Arg
argCChar    = mkStorableArg ffi_type_schar
argCUChar   :: CUChar -> Arg
argCUChar   = mkStorableArg ffi_type_uchar

argCWchar   :: CWchar -> Arg
argCWchar   = mkStorableArg ffi_type_schar

argPtr      :: Ptr a -> Arg
argPtr      = mkStorableArg ffi_type_pointer

argFunPtr   :: FunPtr a -> Arg
argFunPtr   = mkStorableArg ffi_type_pointer

{- | The string argument is passed to C as a char * pointer, which is freed afterwards.
     The argument should not contain zero-bytes. -}
argString   :: String -> Arg
argString   = customPointerArg newCString free

-- | Like argString, but for ByteString's.
argByteString  :: BS.ByteString -> Arg
argByteString  = customPointerArg (flip BS.useAsCString return) (const $ return ())

-- | Like argByteString, but changing the string from C breaks referential transparency.
argConstByteString  :: BS.ByteString -> Arg
argConstByteString  = customPointerArg (flip BSU.unsafeUseAsCString return) (const $ return ())

retVoid     :: RetType ()
retVoid     = RetType ffi_type_void (\write -> write nullPtr >> return ())

retCInt     :: RetType CInt
retCInt     = mkStorableRetType ffi_type_sint
retCUInt    :: RetType CUInt
retCUInt    = mkStorableRetType ffi_type_uint
retCLong    :: RetType CLong
retCLong    = mkStorableRetType ffi_type_slong
retCULong   :: RetType CULong
retCULong   = mkStorableRetType ffi_type_ulong

retInt      :: RetType Int
retInt      = mkStorableRetType ffi_type_hs_int
retInt8     :: RetType Int8
retInt8     = mkStorableRetType ffi_type_sint8
retInt16    :: RetType Int16
retInt16    = mkStorableRetType ffi_type_sint16
retInt32    :: RetType Int32
retInt32    = mkStorableRetType ffi_type_sint32
retInt64    :: RetType Int64
retInt64    = mkStorableRetType ffi_type_sint64

retWord     :: RetType Word
retWord     = mkStorableRetType ffi_type_hs_word
retWord8    :: RetType Word8
retWord8    = mkStorableRetType ffi_type_uint8
retWord16   :: RetType Word16
retWord16   = mkStorableRetType ffi_type_uint16
retWord32   :: RetType Word32
retWord32   = mkStorableRetType ffi_type_uint32
retWord64   :: RetType Word64
retWord64   = mkStorableRetType ffi_type_uint64

retCFloat   :: RetType CFloat
retCFloat   = mkStorableRetType ffi_type_float
retCDouble  :: RetType CDouble
retCDouble  = mkStorableRetType ffi_type_double

retCSize    :: RetType CSize
retCSize    = mkStorableRetType ffi_type_size
retCTime    :: RetType CTime
retCTime    = mkStorableRetType ffi_type_time

retCChar    :: RetType CChar
retCChar    = mkStorableRetType ffi_type_schar
retCUChar   :: RetType CUChar
retCUChar   = mkStorableRetType ffi_type_uchar

retCWchar   :: RetType CWchar
retCWchar   = mkStorableRetType ffi_type_schar

retFunPtr   :: RetType a -> RetType (FunPtr a)
retFunPtr _ = mkStorableRetType ffi_type_pointer

retPtr      :: RetType a -> RetType (Ptr a)
retPtr _    = mkStorableRetType ffi_type_pointer

retCString          :: RetType CString
retCString          = retPtr retCChar

{- | Peek a String out of the returned char *. The char * is not freed. -}
retString           :: RetType String
retString           = withRetType peekCString (retPtr retCChar)

{- | Like retString, but for ByteString's -}
retByteString       :: RetType BS.ByteString
retByteString       = withRetType BS.packCString (retPtr retCChar)

{- | Make a ByteString out of the returned char *.
     The char * will be free(3)ed when the ByteString is garbage collected. -}
retMallocByteString :: RetType BS.ByteString
retMallocByteString = withRetType BSU.unsafePackMallocCString (retPtr retCChar)