{-# OPTIONS_LHC -N -fffi -funboxed-values -fm4 #-}

m4_include(Lhc/Order.m4)
m4_include(Foreign/Storable.m4)

module Lhc.Addr(
    Addr(..),
    FunAddr(..),
    Ptr(..),
    FunPtr(..),
    ptrFromAddr__,
    nullAddr,
    castPtr,
    nullFunAddr,
    plusAddr,
    addrToWordPtr,
    wordPtrToAddr,
    wordPtrToFunAddr,
    funAddrToWordPtr
    ) where

import Lhc.Int
import Data.Word
import Lhc.Prim
import Lhc.Types
import Lhc.Order
import Lhc.Basics
import Lhc.IO
import Foreign.Storable

data Addr = Addr BitsPtr_
data FunAddr = FunAddr BitsPtr_

newtype Ptr a = Ptr Addr
newtype FunPtr a = FunPtr FunAddr

nullAddr = Addr 0#
nullFunAddr = FunAddr 0#

INST_EQORDER(Addr,BitsPtr_)
INST_EQORDER(FunAddr,BitsPtr_)

INST_STORABLE(Addr,BitsPtr_,bits<ptr>)
INST_STORABLE(FunAddr,BitsPtr_,bits<ptr>)

{-# INLINE plusAddr #-}
plusAddr :: Addr -> Int -> Addr
plusAddr (Addr addr) off = case unboxInt off of
    off_ -> Addr (addr `plusWordPtr` intToPtr__ off_)

foreign import primitive "U2U" addrToWordPtr :: Addr -> WordPtr
foreign import primitive "U2U" wordPtrToAddr :: WordPtr -> Addr
foreign import primitive "U2U" wordPtrToFunAddr :: WordPtr -> FunAddr
foreign import primitive "U2U" funAddrToWordPtr :: FunAddr -> WordPtr

foreign import primitive "Sx" intToPtr__ :: Int__ -> BitsPtr_

foreign import primitive "Add" plusWordPtr :: BitsPtr_ -> BitsPtr_ -> BitsPtr_

ptrFromAddr__ :: Addr__ -> Ptr a
ptrFromAddr__ addr = Ptr (Addr addr)

instance Storable (Ptr a) where
    sizeOf (Ptr a) = sizeOf a
    alignment (Ptr a) = alignment a
    peek p = peek (castPtr p) `thenIO` (returnIO . Ptr)
    poke p (Ptr x) = poke (castPtr p) x

instance Eq (Ptr a) where
    Ptr a == Ptr b = a == b
    Ptr a /= Ptr b = a /= b

instance Ord (Ptr a) where
    compare (Ptr a) (Ptr b) = compare a b
    Ptr a <= Ptr b = a <= b
    Ptr a < Ptr b = a < b
    Ptr a > Ptr b = a > b
    Ptr a >= Ptr b = a >= b

castPtr :: Ptr a -> Ptr b
castPtr (Ptr addr) = Ptr addr