Collection.hs

--
-- Copyright (c) 2009-2011, ERICSSON AB
-- All rights reserved.
-- 
-- Redistribution and use in source and binary forms, with or without
-- modification, are permitted provided that the following conditions are met:
-- 
--     * Redistributions of source code must retain the above copyright notice, 
--       this list of conditions and the following disclaimer.
--     * Redistributions in binary form must reproduce the above copyright
--       notice, this list of conditions and the following disclaimer in the
--       documentation and/or other materials provided with the distribution.
--     * Neither the name of the ERICSSON AB nor the names of its contributors
--       may be used to endorse or promote products derived from this software
--       without specific prior written permission.
-- 
-- THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
-- AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
-- IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 
-- DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
-- FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
-- DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
-- SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
-- CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
-- OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-- OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
--

-- | General interfaces to collections of data

module Feldspar.Core.Collection where



import Feldspar.Core.Types
import Feldspar.Core.Frontend



-- | Collection element type
type family Elem a

-- | Collection index type
type family CollIndex a

-- | Collection size type
type family CollSize a

type instance Elem      (Data [a]) = Data a
type instance CollIndex (Data [a]) = Data Index
type instance CollSize  (Data [a]) = Data Length

-- | Data structures that support indexing
class Indexed a
  where
    (!) :: a -> CollIndex a -> Elem a

infixl 9 !

instance Type a => Indexed (Data [a])
  where
    (!) = getIx

-- | Sized data structures
class Sized a
  where
    collSize    :: a -> CollSize a
    setCollSize :: CollSize a -> a -> a

instance Type a => Sized (Data [a])
  where
    collSize    = getLength
    setCollSize = setLength

class CollMap a b
  where
    collMap :: (Elem a -> Elem b) -> a -> b

instance (Type a, Type b) => CollMap (Data [a]) (Data [b])
  where
    collMap f arr = parallel (getLength arr) (f . getIx arr)

-- | Array patch
(|>) :: (Sized a, CollMap a a) =>
    Patch (CollSize a) (CollSize a) -> Patch (Elem a) (Elem a) -> Patch a a
(sizePatch |> elemPatch) a =
    collMap elemPatch $ setCollSize (sizePatch (collSize a)) a