NestedUnboxed.hs

-- |
-- Module      : Data.Vector.Unboxed.Nested
-- Copyright   : (c) Justus Sagemüller 2017
-- License     : BSD-style
-- 
-- Maintainer  : (@) jsagemue $ uni-koeln.de
-- Stability   : experimental
-- Portability : portable
-- 

{-# LANGUAGE TypeFamilies          #-}
{-# LANGUAGE MultiParamTypeClasses #-}

module Data.Vector.Unboxed.Nested where


import Data.Vector.Generic as G
import Data.Vector.Generic.Mutable as GM
import Data.Vector.Unboxed as U
import Data.Vector as B

import Control.Monad


data instance U.Vector (U.Vector a) = NestedVector {
        nestedSubvectors :: U.Vector Int
      , flattenedVector :: U.Vector a
      }
newtype instance U.MVector s (U.Vector a) = NestedMVector {
        getNestedMVector :: B.MVector s (U.Vector a)
      }

instance U.Unbox a => G.Vector U.Vector (U.Vector a) where
  basicLength = pred . G.basicLength . nestedSubvectors
  basicUnsafeIndexM (NestedVector ixs flt) i = do
        i₀ <- basicUnsafeIndexM ixs i
        ie <- basicUnsafeIndexM ixs (i+1)
        return $ G.basicUnsafeSlice i₀ (ie-i₀) flt
  basicUnsafeSlice (NestedVector ixs flt) i = do

instance U.Unbox a => GM.MVector U.MVector (U.Vector a) where

-- instance U.Unbox a => U.Unbox (U.Vector a)

Rough sketch of how a speculative implementation of nested unboxed vectors might work.