-----------------------------------------------------------------------------
-- |
-- Module      :  Data.Counters
-- Copyright   :  (c) 2020-2021 EMQ Technologies Co., Ltd.
-- License     :  BSD-style (see the LICENSE file)
--
-- Maintainer  :  Feng Lee, feng@emqx.io
--                Yang M, yangm@emqx.io
-- Stability   :  experimental
-- Portability :  portable
--
-- The Counters module.
--
-----------------------------------------------------------------------------
module Data.Counters where

import Control.Monad (IO)
import Data.Unit (Unit)
import Foreign (ffiIO1, ffiIO2, ffiIO3)

foreign import data CountersRef :: Type

data CountersOpt = Atomics | WriteConcurrency

type CountersInfo =
  { size   :: Integer
    -- ^ The number of counters in the array.
  , memory :: Integer
    -- ^ Approximate memory consumption for the array in bytes.
  }

foreign import new :: Integer -> CountersOpt -> IO CountersRef

get :: CountersRef -> Integer -> IO Integer
get = ffiIO2 :counters :get

add :: CountersRef -> Integer -> Integer -> IO ()
add = ffiIO3 :counters :add

sub :: CountersRef -> Integer -> Integer -> IO ()
sub = ffiIO3 :counters :sub

put :: CountersRef -> Integer -> Integer -> IO ()
put = ffiIO3 :counters :put

info :: CountersRef -> IO CountersInfo
info = ffiIO1 :counters :info