{-# LANGUAGE Trustworthy #-}
{-# LANGUAGE CPP, NoImplicitPrelude, ScopedTypeVariables, BangPatterns #-}

-----------------------------------------------------------------------------
-- |
-- Module      :  Foreign.Storable
-- Copyright   :  (c) The FFI task force 2001
-- License     :  see libraries/base/LICENSE
-- 
-- Maintainer  :  ffi@haskell.org
-- Stability   :  provisional
-- Portability :  portable
--
-- The module "Foreign.Storable" provides most elementary support for
-- marshalling and is part of the language-independent portion of the
-- Foreign Function Interface (FFI), and will normally be imported via
-- the "Foreign" module.
--
-----------------------------------------------------------------------------

module Foreign.Storable
        ( Storable(
             sizeOf,
             alignment,
             peekElemOff,
             pokeElemOff,
             peekByteOff,
             pokeByteOff,
             peek,
             poke)
        ) where


#include "MachDeps.h"
#include "HsBaseConfig.h"

import GHC.Storable
import GHC.Stable       ( StablePtr )
import GHC.Num
import GHC.Int
import GHC.Word
import GHC.Ptr
import GHC.Base
import GHC.Fingerprint.Type
import Data.Bits
import GHC.Real

{- |
The member functions of this class facilitate writing values of
primitive types to raw memory (which may have been allocated with the
above mentioned routines) and reading values from blocks of raw
memory.  The class, furthermore, includes support for computing the
storage requirements and alignment restrictions of storable types.

Memory addresses are represented as values of type @'Ptr' a@, for some
@a@ which is an instance of class 'Storable'.  The type argument to
'Ptr' helps provide some valuable type safety in FFI code (you can\'t
mix pointers of different types without an explicit cast), while
helping the Haskell type system figure out which marshalling method is
needed for a given pointer.

All marshalling between Haskell and a foreign language ultimately
boils down to translating Haskell data structures into the binary
representation of a corresponding data structure of the foreign
language and vice versa.  To code this marshalling in Haskell, it is
necessary to manipulate primitive data types stored in unstructured
memory blocks.  The class 'Storable' facilitates this manipulation on
all types for which it is instantiated, which are the standard basic
types of Haskell, the fixed size @Int@ types ('Int8', 'Int16',
'Int32', 'Int64'), the fixed size @Word@ types ('Word8', 'Word16',
'Word32', 'Word64'), 'StablePtr', all types from "Foreign.C.Types",
as well as 'Ptr'.
-}

class Storable a where
   {-# MINIMAL sizeOf, alignment,
               (peek | peekElemOff | peekByteOff),
               (poke | pokeElemOff | pokeByteOff) #-}

   sizeOf      :: a -> Int
   -- ^ Computes the storage requirements (in bytes) of the argument.
   -- The value of the argument is not used.

   alignment   :: a -> Int
   -- ^ Computes the alignment constraint of the argument.  An
   -- alignment constraint @x@ is fulfilled by any address divisible
   -- by @x@. The alignment must be a power of two if this instance
   -- is to be used with 'alloca' or 'allocaArray'.  The value of
   -- the argument is not used.

   peekElemOff :: Ptr a -> Int      -> IO a
   -- ^       Read a value from a memory area regarded as an array
   --         of values of the same kind.  The first argument specifies
   --         the start address of the array and the second the index into
   --         the array (the first element of the array has index
   --         @0@).  The following equality holds,
   -- 
   -- > peekElemOff addr idx = IOExts.fixIO $ \result ->
   -- >   peek (addr `plusPtr` (idx * sizeOf result))
   --
   --         Note that this is only a specification, not
   --         necessarily the concrete implementation of the
   --         function.

   pokeElemOff :: Ptr a -> Int -> a -> IO ()
   -- ^       Write a value to a memory area regarded as an array of
   --         values of the same kind.  The following equality holds:
   -- 
   -- > pokeElemOff addr idx x = 
   -- >   poke (addr `plusPtr` (idx * sizeOf x)) x

   peekByteOff :: Ptr b -> Int      -> IO a
   -- ^       Read a value from a memory location given by a base
   --         address and offset.  The following equality holds:
   --
   -- > peekByteOff addr off = peek (addr `plusPtr` off)

   pokeByteOff :: Ptr b -> Int -> a -> IO ()
   -- ^       Write a value to a memory location given by a base
   --         address and offset.  The following equality holds:
   --
   -- > pokeByteOff addr off x = poke (addr `plusPtr` off) x
  
   peek        :: Ptr a      -> IO a
   -- ^ Read a value from the given memory location.
   --
   --  Note that the peek and poke functions might require properly
   --  aligned addresses to function correctly.  This is architecture
   --  dependent; thus, portable code should ensure that when peeking or
   --  poking values of some type @a@, the alignment
   --  constraint for @a@, as given by the function
   --  'alignment' is fulfilled.

   poke        :: Ptr a -> a -> IO ()
   -- ^ Write the given value to the given memory location.  Alignment
   -- restrictions might apply; see 'peek'.
 
   -- circular default instances
   peekElemOff = a -> Ptr a -> Int -> IO a
peekElemOff_ forall a. HasCallStack => a
undefined
      where peekElemOff_ :: a -> Ptr a -> Int -> IO a
            peekElemOff_ :: a -> Ptr a -> Int -> IO a
peekElemOff_ a
undef Ptr a
ptr Int
off = forall a b. Storable a => Ptr b -> Int -> IO a
peekByteOff Ptr a
ptr (Int
off forall a. Num a => a -> a -> a
* forall a. Storable a => a -> Int
sizeOf a
undef)
   pokeElemOff Ptr a
ptr Int
off a
val = forall a b. Storable a => Ptr b -> Int -> a -> IO ()
pokeByteOff Ptr a
ptr (Int
off forall a. Num a => a -> a -> a
* forall a. Storable a => a -> Int
sizeOf a
val) a
val

   peekByteOff Ptr b
ptr Int
off = forall a. Storable a => Ptr a -> IO a
peek (Ptr b
ptr forall a b. Ptr a -> Int -> Ptr b
`plusPtr` Int
off)
   pokeByteOff Ptr b
ptr Int
off = forall a. Storable a => Ptr a -> a -> IO ()
poke (Ptr b
ptr forall a b. Ptr a -> Int -> Ptr b
`plusPtr` Int
off)

   peek Ptr a
ptr = forall a. Storable a => Ptr a -> Int -> IO a
peekElemOff Ptr a
ptr Int
0
   poke Ptr a
ptr = forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr a
ptr Int
0

-- | @since 4.9.0.0
instance Storable () where
  sizeOf :: () -> Int
sizeOf ()
_ = Int
0
  alignment :: () -> Int
alignment ()
_ = Int
1
  peek :: Ptr () -> IO ()
peek Ptr ()
_ = forall (m :: * -> *) a. Monad m => a -> m a
return ()
  poke :: Ptr () -> () -> IO ()
poke Ptr ()
_ ()
_ = forall (m :: * -> *) a. Monad m => a -> m a
return ()

-- System-dependent, but rather obvious instances

-- | @since 2.01
instance Storable Bool where
   sizeOf :: Bool -> Int
sizeOf Bool
_          = forall a. Storable a => a -> Int
sizeOf (forall a. HasCallStack => a
undefined::HTYPE_INT)
   alignment :: Bool -> Int
alignment Bool
_       = forall a. Storable a => a -> Int
alignment (forall a. HasCallStack => a
undefined::HTYPE_INT)
   peekElemOff :: Ptr Bool -> Int -> IO Bool
peekElemOff Ptr Bool
p Int
i   = forall (m :: * -> *) a1 r. Monad m => (a1 -> r) -> m a1 -> m r
liftM (forall a. Eq a => a -> a -> Bool
/= (Int32
0::HTYPE_INT)) $ peekElemOff (castPtr p) i
   pokeElemOff :: Ptr Bool -> Int -> Bool -> IO ()
pokeElemOff Ptr Bool
p Int
i Bool
x = forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff (forall a b. Ptr a -> Ptr b
castPtr Ptr Bool
p) Int
i (if Bool
x then Int32
1 else Int32
0::HTYPE_INT)

#define STORABLE(T,size,align,read,write)       \
instance Storable (T) where {                   \
    sizeOf    _ = size;                         \
    alignment _ = align;                        \
    peekElemOff = read;                         \
    pokeElemOff = write }

-- | @since 2.01
STORABLE(Char,SIZEOF_INT32,ALIGNMENT_INT32,
         readWideCharOffPtr,writeWideCharOffPtr)

-- | @since 2.01
STORABLE(Int,SIZEOF_HSINT,ALIGNMENT_HSINT,
         readIntOffPtr,writeIntOffPtr)

-- | @since 2.01
STORABLE(Word,SIZEOF_HSWORD,ALIGNMENT_HSWORD,
         readWordOffPtr,writeWordOffPtr)

-- | @since 2.01
STORABLE((Ptr a),SIZEOF_HSPTR,ALIGNMENT_HSPTR,
         readPtrOffPtr,writePtrOffPtr)

-- | @since 2.01
STORABLE((FunPtr a),SIZEOF_HSFUNPTR,ALIGNMENT_HSFUNPTR,
         readFunPtrOffPtr,writeFunPtrOffPtr)

-- | @since 2.01
STORABLE((StablePtr a),SIZEOF_HSSTABLEPTR,ALIGNMENT_HSSTABLEPTR,
         readStablePtrOffPtr,writeStablePtrOffPtr)

-- | @since 2.01
STORABLE(Float,SIZEOF_HSFLOAT,ALIGNMENT_HSFLOAT,
         readFloatOffPtr,writeFloatOffPtr)

-- | @since 2.01
STORABLE(Double,SIZEOF_HSDOUBLE,ALIGNMENT_HSDOUBLE,
         readDoubleOffPtr,writeDoubleOffPtr)

-- | @since 2.01
STORABLE(Word8,SIZEOF_WORD8,ALIGNMENT_WORD8,
         readWord8OffPtr,writeWord8OffPtr)

-- | @since 2.01
STORABLE(Word16,SIZEOF_WORD16,ALIGNMENT_WORD16,
         readWord16OffPtr,writeWord16OffPtr)

-- | @since 2.01
STORABLE(Word32,SIZEOF_WORD32,ALIGNMENT_WORD32,
         readWord32OffPtr,writeWord32OffPtr)

-- | @since 2.01
STORABLE(Word64,SIZEOF_WORD64,ALIGNMENT_WORD64,
         readWord64OffPtr,writeWord64OffPtr)

-- | @since 2.01
STORABLE(Int8,SIZEOF_INT8,ALIGNMENT_INT8,
         readInt8OffPtr,writeInt8OffPtr)

-- | @since 2.01
STORABLE(Int16,SIZEOF_INT16,ALIGNMENT_INT16,
         readInt16OffPtr,writeInt16OffPtr)

-- | @since 2.01
STORABLE(Int32,SIZEOF_INT32,ALIGNMENT_INT32,
         readInt32OffPtr,writeInt32OffPtr)

-- | @since 2.01
STORABLE(Int64,SIZEOF_INT64,ALIGNMENT_INT64,
         readInt64OffPtr,writeInt64OffPtr)

-- | @since 4.8.0.0
instance (Storable a, Integral a) => Storable (Ratio a) where
    sizeOf :: Ratio a -> Int
sizeOf Ratio a
_    = Int
2 forall a. Num a => a -> a -> a
* forall a. Storable a => a -> Int
sizeOf (forall a. HasCallStack => a
undefined :: a)
    alignment :: Ratio a -> Int
alignment Ratio a
_ = forall a. Storable a => a -> Int
alignment (forall a. HasCallStack => a
undefined :: a )
    peek :: Ptr (Ratio a) -> IO (Ratio a)
peek Ptr (Ratio a)
p           = do
                        Ptr a
q <- forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$ forall a b. Ptr a -> Ptr b
castPtr Ptr (Ratio a)
p
                        a
r <- forall a. Storable a => Ptr a -> IO a
peek Ptr a
q
                        a
i <- forall a. Storable a => Ptr a -> Int -> IO a
peekElemOff Ptr a
q Int
1
                        forall (m :: * -> *) a. Monad m => a -> m a
return (a
r forall a. Integral a => a -> a -> Ratio a
% a
i)
    poke :: Ptr (Ratio a) -> Ratio a -> IO ()
poke Ptr (Ratio a)
p (a
r :% a
i)  = do
                        Ptr a
q <-forall (m :: * -> *) a. Monad m => a -> m a
return forall a b. (a -> b) -> a -> b
$  (forall a b. Ptr a -> Ptr b
castPtr Ptr (Ratio a)
p)
                        forall a. Storable a => Ptr a -> a -> IO ()
poke Ptr a
q a
r
                        forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr a
q Int
1 a
i

-- XXX: here to avoid orphan instance in GHC.Fingerprint
-- | @since 4.4.0.0
instance Storable Fingerprint where
  sizeOf :: Fingerprint -> Int
sizeOf Fingerprint
_ = Int
16
  alignment :: Fingerprint -> Int
alignment Fingerprint
_ = Int
8
  peek :: Ptr Fingerprint -> IO Fingerprint
peek = Ptr Fingerprint -> IO Fingerprint
peekFingerprint
  poke :: Ptr Fingerprint -> Fingerprint -> IO ()
poke = Ptr Fingerprint -> Fingerprint -> IO ()
pokeFingerprint

-- peek/poke in fixed BIG-endian 128-bit format
peekFingerprint :: Ptr Fingerprint -> IO Fingerprint
peekFingerprint :: Ptr Fingerprint -> IO Fingerprint
peekFingerprint Ptr Fingerprint
p0 = do
      let peekW64 :: Ptr Word8 -> Int -> Word64 -> IO Word64
          peekW64 :: Ptr Word8 -> Int -> Word64 -> IO Word64
peekW64 Ptr Word8
_  Int
0  !Word64
i = forall (m :: * -> *) a. Monad m => a -> m a
return Word64
i
          peekW64 !Ptr Word8
p !Int
n !Word64
i = do
                Word8
w8 <- forall a. Storable a => Ptr a -> IO a
peek Ptr Word8
p
                Ptr Word8 -> Int -> Word64 -> IO Word64
peekW64 (Ptr Word8
p forall a b. Ptr a -> Int -> Ptr b
`plusPtr` Int
1) (Int
nforall a. Num a => a -> a -> a
-Int
1) 
                    ((Word64
i forall a. Bits a => a -> Int -> a
`shiftL` Int
8) forall a. Bits a => a -> a -> a
.|. forall a b. (Integral a, Num b) => a -> b
fromIntegral Word8
w8)

      Word64
high <- Ptr Word8 -> Int -> Word64 -> IO Word64
peekW64 (forall a b. Ptr a -> Ptr b
castPtr Ptr Fingerprint
p0) Int
8 Word64
0
      Word64
low  <- Ptr Word8 -> Int -> Word64 -> IO Word64
peekW64 (forall a b. Ptr a -> Ptr b
castPtr Ptr Fingerprint
p0 forall a b. Ptr a -> Int -> Ptr b
`plusPtr` Int
8) Int
8 Word64
0
      forall (m :: * -> *) a. Monad m => a -> m a
return (Word64 -> Word64 -> Fingerprint
Fingerprint Word64
high Word64
low)

pokeFingerprint :: Ptr Fingerprint -> Fingerprint -> IO ()
pokeFingerprint :: Ptr Fingerprint -> Fingerprint -> IO ()
pokeFingerprint Ptr Fingerprint
p0 (Fingerprint Word64
high Word64
low) = do
      let pokeW64 :: Ptr Word8 -> Int -> Word64 -> IO ()
          pokeW64 :: Ptr Word8 -> Int -> Word64 -> IO ()
pokeW64 Ptr Word8
_ Int
0  Word64
_  = forall (m :: * -> *) a. Monad m => a -> m a
return ()
          pokeW64 Ptr Word8
p !Int
n !Word64
i = do
                forall a. Storable a => Ptr a -> Int -> a -> IO ()
pokeElemOff Ptr Word8
p (Int
nforall a. Num a => a -> a -> a
-Int
1) (forall a b. (Integral a, Num b) => a -> b
fromIntegral Word64
i)
                Ptr Word8 -> Int -> Word64 -> IO ()
pokeW64 Ptr Word8
p (Int
nforall a. Num a => a -> a -> a
-Int
1) (Word64
i forall a. Bits a => a -> Int -> a
`shiftR` Int
8)

      Ptr Word8 -> Int -> Word64 -> IO ()
pokeW64 (forall a b. Ptr a -> Ptr b
castPtr Ptr Fingerprint
p0) Int
8 Word64
high
      Ptr Word8 -> Int -> Word64 -> IO ()
pokeW64 (forall a b. Ptr a -> Ptr b
castPtr Ptr Fingerprint
p0 forall a b. Ptr a -> Int -> Ptr b
`plusPtr` Int
8) Int
8 Word64
low