Common.hs

{-# OPTIONS -Wall #-}
----------------------------------------------------------------------
-- |
-- Module      : Data.ZoomCache.Write
-- Copyright   : Conrad Parker
-- License     : BSD3-style (see LICENSE)
--
-- Maintainer  : Conrad Parker <conrad@metadecks.org>
-- Stability   : unstable
-- Portability : unknown
--
-- Types used throughout zoom-cache
----------------------------------------------------------------------

module Data.ZoomCache.Common (
  -- * Types
    TimeStamp(..)
  , TrackType(..)
  , DataRateType(..)
  , TrackNo

  -- * Global header
  , Global(..)

  -- * CacheFile
  , CacheFile(..)
  , mkCacheFile
  , fiFull

  -- * Version
  , Version(..)

  -- * Track specification
  , TrackMap
  , TrackSpec(..)
) where

import qualified Data.ByteString.Lazy as L
import Data.IntMap (IntMap)
import qualified Data.IntMap as IM

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

type TrackNo = Int

data TimeStamp = TS { unTS :: !Integer }
    deriving (Eq, Ord, Show)

data Version = Version Int Int
    deriving (Eq, Show)

data Global = Global
    { version          :: Version
    , noTracks         :: Int
    , presentationTime :: Rational
    , baseTime         :: Rational
    , baseUTC          :: Maybe Int -- UTCTime
    }
    deriving (Show)

-- | A map of all track numbers to their 'TrackSpec'
type TrackMap = IntMap TrackSpec

-- | A specification of the type and name of each track
data TrackSpec = TrackSpec
    { specType   :: TrackType
    , specDRType :: DataRateType
    , specRate   :: Rational
    , specName   :: L.ByteString
    }
    deriving (Show)

data TrackType = ZDouble | ZInt
    deriving (Eq, Show)

-- | Constant or Variable datarate.
-- For constant datarate, timestamps are implied as incrementing by 1/datarate
-- For variable datarate, explicit timestamps are attached to each datum, encoded
-- as a separate block of timestamps in the Raw Data packet.
data DataRateType = ConstantDR | VariableDR
    deriving (Show)

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

-- | Global and track headers for a zoom-cache file
data CacheFile = CacheFile
    { cfGlobal :: Global
    , cfSpecs  :: IntMap TrackSpec
    }

-- | Create an empty 'CacheFile' using the given 'Global'
mkCacheFile :: Global -> CacheFile
mkCacheFile g = CacheFile g IM.empty

-- | Determine whether all tracks of a 'CacheFile' are specified
fiFull :: CacheFile -> Bool
fiFull (CacheFile g specs) = IM.size specs == noTracks g