-- |

-- Module:      Data.Aeson.Functions

-- Copyright:   (c) 2011-2016 Bryan O'Sullivan

--              (c) 2011 MailRank, Inc.

-- License:     BSD3

-- Maintainer:  Bryan O'Sullivan <bos@serpentine.com>

-- Stability:   experimental

-- Portability: portable

module Data.Aeson.Internal.Functions

    (

      mapHashKeyVal

    , mapKeyVal

    , mapKey

    ) where

import Prelude ()

import Prelude.Compat

import Data.Hashable (Hashable)

import qualified Data.HashMap.Strict as H

import qualified Data.Map as M

-- | Transform a 'M.Map' into a 'H.HashMap' while transforming the keys.

mapHashKeyVal :: (Eq k2, Hashable k2) => (k1 -> k2) -> (v1 -> v2)

              -> M.Map k1 v1 -> H.HashMap k2 v2

mapHashKeyVal fk kv = M.foldrWithKey (\k v -> H.insert (fk k) (kv v)) H.empty

{-# INLINE mapHashKeyVal #-}

-- | Transform the keys and values of a 'H.HashMap'.

mapKeyVal :: (Eq k2, Hashable k2) => (k1 -> k2) -> (v1 -> v2)

          -> H.HashMap k1 v1 -> H.HashMap k2 v2

mapKeyVal fk kv = H.foldrWithKey (\k v -> H.insert (fk k) (kv v)) H.empty

{-# INLINE mapKeyVal #-}

-- | Transform the keys of a 'H.HashMap'.

mapKey :: (Eq k2, Hashable k2) => (k1 -> k2) -> H.HashMap k1 v -> H.HashMap k2 v

mapKey fk = mapKeyVal fk id

{-# INLINE mapKey #-}