Types.hs

{-# LANGUAGE DeriveAnyClass #-}
{-# LANGUAGE DeriveGeneric #-}

module Tahoe.CHK.Types where

import Data.Word (
    Word16,
    Word8,
 )

import qualified Data.ByteString as B
import Data.TreeDiff.Class (ToExpr)
import GHC.Generics (Generic)

-- 16 bytes
type StorageIndex = B.ByteString

-- How much data is there
type Size = Integer

-- Byte-based position into a share
type Offset = Integer

-- Segment-based position into a share
type SegmentNum = Int

-- With respect to FEC encoding, the number of a share.
type ShareNum = Word8

-- The SHA256d hash of a FEC-encoded block
type BlockHash = B.ByteString

-- The SHA256d hash of some ciphertext
type CrypttextHash = B.ByteString

-- Erasure encoding / placement parameters
type Total = Word16
type Happy = ShareNum -- This is not like the others.
type Required = Word16
type SegmentSize = Size
data Parameters = Parameters
    { paramSegmentSize :: SegmentSize
    , paramTotalShares :: Total
    , paramHappyShares :: Happy
    , paramRequiredShares :: Required
    }
    deriving (Show, Ord, Eq, Generic, ToExpr)

requiredToInt :: Required -> Int
requiredToInt = fromIntegral

totalToInt :: Total -> Int
totalToInt = fromIntegral