{-# LANGUAGE MagicHash, CPP, UnboxedTuples, BangPatterns, FlexibleContexts #-}
-----------------------------------------------------------------------------
-- |
-- Module      :  Data.Packed.Internal.Vector
-- Copyright   :  (c) Alberto Ruiz 2007
-- License     :  GPL-style
--
-- Maintainer  :  Alberto Ruiz <aruiz@um.es>
-- Stability   :  provisional
-- Portability :  portable (uses FFI)
--
-- Vector implementation
--
-----------------------------------------------------------------------------

module Data.Packed.Internal.Vector (
    Vector, dim,
    fromList, toList, (|>),
    join, (@>), safe, at, at', subVector, takesV,
    mapVector, zipVector, unzipVectorWith,
    foldVector, foldVectorG, foldLoop,
    createVector, vec,
    asComplex, asReal,
    fwriteVector, freadVector, fprintfVector, fscanfVector,
    cloneVector,
    unsafeToForeignPtr,
    unsafeFromForeignPtr,
    unsafeWith
) where

import Data.Packed.Internal.Common
import Data.Packed.Internal.Signatures
import Foreign
import Foreign.C.String
import Foreign.C.Types(CInt,CChar)
import Data.Complex
import Control.Monad(when)

#if __GLASGOW_HASKELL__ >= 605
import GHC.ForeignPtr           (mallocPlainForeignPtrBytes)
#else
import Foreign.ForeignPtr       (mallocForeignPtrBytes)
#endif

import GHC.Base
#if __GLASGOW_HASKELL__ < 612
import GHC.IOBase
#endif

#ifdef VECTOR
import qualified Data.Vector.Storable as Vector
import Data.Vector.Storable(Vector,
                            unsafeToForeignPtr,
                            unsafeFromForeignPtr,
                            unsafeWith)
#endif

#ifdef VECTOR

-- | Number of elements
dim :: (Storable t) => Vector t -> Int
dim = Vector.length

#else

-- | One-dimensional array of objects stored in a contiguous memory block.
data Vector t =
    V { ioff :: {-# UNPACK #-} !Int              -- ^ offset of first element
      , idim :: {-# UNPACK #-} !Int              -- ^ number of elements
      , fptr :: {-# UNPACK #-} !(ForeignPtr t)   -- ^ foreign pointer to the memory block
      }

unsafeToForeignPtr :: Vector a -> (ForeignPtr a, Int, Int)
unsafeToForeignPtr v = (fptr v, ioff v, idim v)

-- | Same convention as in Roman Leshchinskiy's vector package.
unsafeFromForeignPtr :: ForeignPtr a -> Int -> Int -> Vector a
unsafeFromForeignPtr fp i n | n > 0 = V {ioff = i, idim = n, fptr = fp}
                            | otherwise = error "unsafeFromForeignPtr with dim < 1"

unsafeWith (V i _ fp) m = withForeignPtr fp $ \p -> m (p `advancePtr` i)
{-# INLINE unsafeWith #-}

-- | Number of elements
dim :: (Storable t) => Vector t -> Int
dim = idim

#endif


-- C-Haskell vector adapter
-- vec :: Adapt (CInt -> Ptr t -> r) (Vector t) r
vec :: (Storable t) => Vector t -> (((CInt -> Ptr t -> t1) -> t1) -> IO b) -> IO b
vec x f = unsafeWith x $ \p -> do
    let v g = do
        g (fi $ dim x) p
    f v
{-# INLINE vec #-}


-- allocates memory for a new vector
createVector :: Storable a => Int -> IO (Vector a)
createVector n = do
    when (n <= 0) $ error ("trying to createVector of dim "++show n)
    fp <- doMalloc undefined
    return $ unsafeFromForeignPtr fp 0 n
  where
    --
    -- Use the much cheaper Haskell heap allocated storage
    -- for foreign pointer space we control
    --
    doMalloc :: Storable b => b -> IO (ForeignPtr b)
    doMalloc dummy = do
#if __GLASGOW_HASKELL__ >= 605
        mallocPlainForeignPtrBytes (n * sizeOf dummy)
#else
        mallocForeignPtrBytes      (n * sizeOf dummy)
#endif

{- | creates a Vector from a list:

@> fromList [2,3,5,7]
4 |> [2.0,3.0,5.0,7.0]@

-}
fromList :: Storable a => [a] -> Vector a
fromList l = unsafePerformIO $ do
    v <- createVector (length l)
    unsafeWith v $ \ p -> pokeArray p l
    return v

safeRead v = inlinePerformIO . unsafeWith v
{-# INLINE safeRead #-}

inlinePerformIO :: IO a -> a
inlinePerformIO (IO m) = case m realWorld# of (# _, r #) -> r
{-# INLINE inlinePerformIO #-}

{- | extracts the Vector elements to a list

@> toList (linspace 5 (1,10))
[1.0,3.25,5.5,7.75,10.0]@

-}
toList :: Storable a => Vector a -> [a]
toList v = safeRead v $ peekArray (dim v)

{- | An alternative to 'fromList' with explicit dimension. The input
     list is explicitly truncated if it is too long, so it may safely
     be used, for instance, with infinite lists.

     This is the format used in the instances for Show (Vector a).
-}
(|>) :: (Storable a) => Int -> [a] -> Vector a
infixl 9 |>
n |> l = if length l' == n
            then fromList l'
            else error "list too short for |>"
  where l' = take n l


-- | access to Vector elements without range checking
at' :: Storable a => Vector a -> Int -> a
at' v n = safeRead v $ flip peekElemOff n
{-# INLINE at' #-}

--
-- turn off bounds checking with -funsafe at configure time.
-- ghc will optimise away the salways true case at compile time.
--
#if defined(UNSAFE)
safe :: Bool
safe = False
#else
safe = True
#endif

-- | access to Vector elements with range checking.
at :: Storable a => Vector a -> Int -> a
at v n
    | safe      = if n >= 0 && n < dim v
                    then at' v n
                    else error "vector index out of range"
    | otherwise = at' v n
{-# INLINE at #-}

{- | takes a number of consecutive elements from a Vector

@> subVector 2 3 (fromList [1..10])
3 |> [3.0,4.0,5.0]@

-}
subVector :: Storable t => Int       -- ^ index of the starting element
                        -> Int       -- ^ number of elements to extract
                        -> Vector t  -- ^ source
                        -> Vector t  -- ^ result

#ifdef VECTOR

subVector = Vector.slice

#else

subVector k l v@V{idim = n, ioff = i}
    | k<0 || k >= n || k+l > n || l < 0 = error "subVector out of range"
    | otherwise = v {idim = l, ioff = i+k}

subVectorCopy k l (v@V {idim=n})
    | k<0 || k >= n || k+l > n || l < 0 = error "subVector out of range"
    | otherwise = unsafePerformIO $ do
        r <- createVector l
        let f _ s _ d = copyArray d (advancePtr s k) l >> return 0
        app2 f vec v vec r "subVector"
        return r

#endif

{- | Reads a vector position:

@> fromList [0..9] \@\> 7
7.0@

-}
(@>) :: Storable t => Vector t -> Int -> t
infixl 9 @>
(@>) = at


{- | creates a new Vector by joining a list of Vectors

@> join [fromList [1..5], constant 1 3]
8 |> [1.0,2.0,3.0,4.0,5.0,1.0,1.0,1.0]@

-}
join :: Storable t => [Vector t] -> Vector t
join [] = error "joining zero vectors"
join [v] = v
join as = unsafePerformIO $ do
    let tot = sum (map dim as)
    r <- createVector tot
    unsafeWith r $ \ptr ->
        joiner as tot ptr
    return r
  where joiner [] _ _ = return ()
        joiner (v:cs) _ p = do
            let n = dim v
            unsafeWith v $ \pb -> copyArray p pb n
            joiner cs 0 (advancePtr p n)


{- | Extract consecutive subvectors of the given sizes.

@> takesV [3,4] (linspace 10 (1,10))
[3 |> [1.0,2.0,3.0],4 |> [4.0,5.0,6.0,7.0]]@

-}
takesV :: Storable t => [Int] -> Vector t -> [Vector t]
takesV ms w | sum ms > dim w = error $ "takesV " ++ show ms ++ " on dim = " ++ (show $ dim w)
            | otherwise = go ms w
    where go [] _ = []
          go (n:ns) v = subVector 0 n v
                      : go ns (subVector n (dim v - n) v)

---------------------------------------------------------------

-- | transforms a complex vector into a real vector with alternating real and imaginary parts 
asReal :: Vector (Complex a) -> Vector a
--asReal v = V { ioff = 2*ioff v, idim = 2*dim v, fptr =  castForeignPtr (fptr v) }
asReal v = unsafeFromForeignPtr (castForeignPtr fp) (2*i) (2*n)
    where (fp,i,n) = unsafeToForeignPtr v

-- | transforms a real vector into a complex vector with alternating real and imaginary parts
asComplex :: Vector a -> Vector (Complex a)
--asComplex v = V { ioff = ioff v `div` 2, idim = dim v `div` 2, fptr =  castForeignPtr (fptr v) }
asComplex v = unsafeFromForeignPtr (castForeignPtr fp) (i `div` 2) (n `div` 2)
    where (fp,i,n) = unsafeToForeignPtr v

----------------------------------------------------------------

cloneVector :: Storable t => Vector t -> IO (Vector t)
cloneVector v = do
        let n = dim v
        r <- createVector n
        let f _ s _ d =  copyArray d s n >> return 0
        app2 f vec v vec r "cloneVector"
        return r

------------------------------------------------------------------

-- | map on Vectors
mapVector :: (Storable a, Storable b) => (a-> b) -> Vector a -> Vector b
mapVector f v = unsafePerformIO $ do
    w <- createVector (dim v)
    unsafeWith v $ \p ->
        unsafeWith w $ \q -> do
            let go (-1) = return ()
                go !k = do x <- peekElemOff p k
                           pokeElemOff      q k (f x)
                           go (k-1)
            go (dim v -1)
    return w
{-# INLINE mapVector #-}

-- | zipWith for Vectors
zipVector :: (Storable a, Storable b, Storable c) => (a-> b -> c) -> Vector a -> Vector b -> Vector c
zipVector f u v = unsafePerformIO $ do
    let n = min (dim u) (dim v)
    w <- createVector n
    unsafeWith u $ \pu ->
        unsafeWith v $ \pv ->
            unsafeWith w $ \pw -> do
                let go (-1) = return ()
                    go !k = do x <- peekElemOff pu k
                               y <- peekElemOff pv k
                               pokeElemOff      pw k (f x y)
                               go (k-1)
                go (n -1)
    return w
{-# INLINE zipVector #-}

-- | unzipWith for Vectors
unzipVectorWith :: (Storable (a,b), Storable c, Storable d) 
                   => (a -> c) -> (b -> d) -> Vector (a,b) -> (Vector c,Vector d)
unzipVectorWith f g u = unsafePerformIO $ do
      let n = dim u
      v <- createVector n
      w <- createVector n
      unsafeWith u $ \pu ->
          unsafeWith v $ \pv ->
              unsafeWith w $ \pw -> do
                  let go (-1) = return ()
                      go !k   = do (x,y) <- peekElemOff pu k
                                   pokeElemOff          pv k (f x)
                                   pokeElemOff          pw k (g y)
                                   go (k-1)
                  go (n-1)
      return (v,w)
{-# INLINE unzipVectorWith #-}

foldVector f x v = unsafePerformIO $
    unsafeWith (v::Vector Double) $ \p -> do
        let go (-1) s = return s
            go !k !s = do y <- peekElemOff p k
                          go (k-1::Int) (f y s)
        go (dim v -1) x
{-# INLINE foldVector #-}

foldLoop f s0 d = go (d - 1) s0
     where
       go 0 s = f (0::Int) s
       go !j !s = go (j - 1) (f j s)

foldVectorG f s0 v = foldLoop g s0 (dim v)
    where g !k !s = f k (at' v) s
          {-# INLINE g #-} -- Thanks to Ryan Ingram (http://permalink.gmane.org/gmane.comp.lang.haskell.cafe/46479)
{-# INLINE foldVectorG #-}

-------------------------------------------------------------------

-- | Loads a vector from an ASCII file (the number of elements must be known in advance).
fscanfVector :: FilePath -> Int -> IO (Vector Double)
fscanfVector filename n = do
    charname <- newCString filename
    res <- createVector n
    app1 (gsl_vector_fscanf charname) vec res "gsl_vector_fscanf"
    free charname
    return res

foreign import ccall "vector_fscanf" gsl_vector_fscanf:: Ptr CChar -> TV

-- | Saves the elements of a vector, with a given format (%f, %e, %g), to an ASCII file.
fprintfVector :: FilePath -> String -> Vector Double -> IO ()
fprintfVector filename fmt v = do
    charname <- newCString filename
    charfmt <- newCString fmt
    app1 (gsl_vector_fprintf charname charfmt) vec v "gsl_vector_fprintf"
    free charname
    free charfmt

foreign import ccall "vector_fprintf" gsl_vector_fprintf :: Ptr CChar -> Ptr CChar -> TV

-- | Loads a vector from a binary file (the number of elements must be known in advance).
freadVector :: FilePath -> Int -> IO (Vector Double)
freadVector filename n = do
    charname <- newCString filename
    res <- createVector n
    app1 (gsl_vector_fread charname) vec res "gsl_vector_fread"
    free charname
    return res

foreign import ccall "vector_fread" gsl_vector_fread:: Ptr CChar -> TV

-- | Saves the elements of a vector to a binary file.
fwriteVector :: FilePath -> Vector Double -> IO ()
fwriteVector filename v = do
    charname <- newCString filename
    app1 (gsl_vector_fwrite charname) vec v "gsl_vector_fwrite"
    free charname

foreign import ccall "vector_fwrite" gsl_vector_fwrite :: Ptr CChar -> TV