{- | Arguments and return types.

    Note that functions for 'Int' and 'Word' are not provided here, as Haskell merely defines that
    'Int' is a \"fixed-precision integer type with at least the range [-2^29 .. 2^29-1]\",
    and 'Word' is an \"unsigned integral type, with the same size as 'Int'\".
    (As both types are instances of 'Storable', the user may easily define them himself when determined useful.)

    Note also that on e.g. Linux x86_64, 'Int' \/= 'CInt'.
    -}
module Foreign.CInvoke.Types (
    -- * Arguments
    -- ** Integral types
    argCShort,
    argCUShort,
    argCInt,
    argCUInt,
    argCLong,
    argCULong,
    argCLLong,
    argCULLong,
    argInt8,
    argInt16,
    argInt32,
    argInt64,
    argWord8,
    argWord16,
    argWord32,
    argWord64,
    -- ** Floating point types
    argCFloat,
    argCDouble,
    -- ** Various other C types
    argCSize,
    argCTime,
    argCChar,
    argCSChar,
    argCUChar,
    argCWchar,
    argPtr,
    argFunPtr,
    -- ** Strings
    argString,
    argByteString,
    argConstByteString,
    -- * Return types
    -- ** Integral types
    retVoid,
    retCShort,
    retCUShort,
    retCInt,
    retCUInt,
    retCLong,
    retCULong,
    retCLLong,
    retCULLong,
    retInt8,
    retInt16,
    retInt32,
    retInt64,
    retWord8,
    retWord16,
    retWord32,
    retWord64,
    -- ** Floating point types
    retCFloat,
    retCDouble,
    -- ** Various other C types
    retCSize,
    retCTime,
    retCChar,
    retCSChar,
    retCUChar,
    retCWchar,
    retPtr,
    retFunPtr,
    -- ** Strings
    retCString,
    retString,
    retByteString,
    retMallocByteString
    ) where

import Control.Monad
import Data.List
import Data.Char
import Data.Int
import Data.Word

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

import Foreign.CInvoke.Base

argCShort   = mkStorableArg     :: CShort -> Arg
argCUShort  = mkStorableArg     :: CUShort -> Arg
argCInt     = mkStorableArg     :: CInt -> Arg
argCUInt    = mkStorableArg     :: CUInt -> Arg
argCLong    = mkStorableArg     :: CLong -> Arg
argCULong   = mkStorableArg     :: CULong -> Arg
argCLLong   = mkStorableArg     :: CLLong -> Arg
argCULLong  = mkStorableArg     :: CULLong -> Arg

argInt8     = mkStorableArg     :: Int8 -> Arg
argInt16    = mkStorableArg     :: Int16 -> Arg
argInt32    = mkStorableArg     :: Int32 -> Arg
argInt64    = mkStorableArg     :: Int64 -> Arg

argWord8    = mkStorableArg     :: Word8 -> Arg
argWord16   = mkStorableArg     :: Word16 -> Arg
argWord32   = mkStorableArg     :: Word32 -> Arg
argWord64   = mkStorableArg     :: Word64 -> Arg

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

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

argCChar    = mkStorableArg     :: CChar -> Arg
argCSChar   = mkStorableArg     :: CSChar -> Arg
argCUChar   = mkStorableArg     :: CUChar -> Arg

argCWchar   = mkStorableArg     :: CWchar -> Arg

argPtr      = mkStorableArg     :: Ptr a -> Arg

argFunPtr   = mkStorableArg     :: FunPtr a -> Arg

{- | 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   = mkPointerArg newCString free

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

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

retVoid     :: RetType ()
retVoid     = RetType (\write -> write 0 nullPtr >> return ())

retCShort   = mkStorableRetType     :: RetType CShort
retCUShort  = mkStorableRetType     :: RetType CUShort
retCInt     = mkStorableRetType     :: RetType CInt
retCUInt    = mkStorableRetType     :: RetType CUInt
retCLong    = mkStorableRetType     :: RetType CLong
retCULong   = mkStorableRetType     :: RetType CULong
retCLLong   = mkStorableRetType     :: RetType CLLong
retCULLong  = mkStorableRetType     :: RetType CULLong

retInt8     = mkStorableRetType     :: RetType Int8
retInt16    = mkStorableRetType     :: RetType Int16
retInt32    = mkStorableRetType     :: RetType Int32
retInt64    = mkStorableRetType     :: RetType Int64

retWord8    = mkStorableRetType     :: RetType Word8
retWord16   = mkStorableRetType     :: RetType Word16
retWord32   = mkStorableRetType     :: RetType Word32
retWord64   = mkStorableRetType     :: RetType Word64

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

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

retCChar    = mkStorableRetType     :: RetType CChar
retCSChar   = mkStorableRetType     :: RetType CSChar
retCUChar   = mkStorableRetType     :: RetType CUChar

retCWchar   = mkStorableRetType     :: RetType CWchar

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

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

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)