module NLP.Text.BTI.Internal where
import Data.IORef (newIORef,IORef,readIORef,atomicWriteIORef,atomicModifyIORef')
import Data.Text (Text)
import System.IO.Unsafe (unsafePerformIO,unsafeDupablePerformIO)
import Data.Bijection.Hash (Bimap,empty,lookupL,lookupR,size,insert)
btiBimap :: IORef (Bimap Text Int)
btiBimap = unsafePerformIO $ newIORef empty
btiBimapAdd :: Text -> Int
btiBimapAdd k = unsafeDupablePerformIO $ atomicModifyIORef' btiBimap $ \m ->
case lookupL m k of Just i -> (m,i)
Nothing -> let s = size m
in (insert m (k,s) , s)
btiBimapLookupInt :: Int -> Text
btiBimapLookupInt r = seq r . unsafeDupablePerformIO $ atomicModifyIORef' btiBimap $ \m ->
case lookupR m r of Just l -> (m,l)
Nothing -> error "btiBimapLookupInt: totality assumption invalidated"