{-# LANGUAGE TypeFamilies #-}
module Data.Digest.CRC64
    ( CRC64(..)
    ) where


--TODO: look to uuid for how they structure modules
--TODO: actually benchmark unboxed vector
-------------------------------------------------------------------------------
import           Data.Bits
import           Data.ByteString     as BS
import           Data.Vector.Unboxed as V
import           Data.Word
-------------------------------------------------------------------------------
import           Data.Digest.CRC
-------------------------------------------------------------------------------


newtype CRC64 = CRC64 { crc64 :: Word64 } deriving (Show, Eq, Ord)


instance CRC CRC64 where
  type CRCWord CRC64 = Word64
  initCRC = CRC64 0
  crcWord = crc64
  updateDigest = updateDigest64
  crcTable = table


-------------------------------------------------------------------------------
updateDigest64 :: CRC64 -> ByteString -> CRC64
updateDigest64 crc = BS.foldl go crc
  where
    go (CRC64 crc') b8 =
      let idx = fromIntegral (crc' `xor` b64) .&. 0xff
          b64 = fromIntegral b8
      in CRC64 (((table ! idx) `xor` (crc' `shiftR` 8)) .&. 0xffffffffffffffff)


-------------------------------------------------------------------------------
table :: V.Vector Word64
table = V.fromList
  [ 0x0000000000000000 , 0x01b0000000000000 , 0x0360000000000000 , 0x02d0000000000000
  , 0x06c0000000000000 , 0x0770000000000000 , 0x05a0000000000000 , 0x0410000000000000
  , 0x0d80000000000000 , 0x0c30000000000000 , 0x0ee0000000000000 , 0x0f50000000000000
  , 0x0b40000000000000 , 0x0af0000000000000 , 0x0820000000000000 , 0x0990000000000000
  , 0x1b00000000000000 , 0x1ab0000000000000 , 0x1860000000000000 , 0x19d0000000000000
  , 0x1dc0000000000000 , 0x1c70000000000000 , 0x1ea0000000000000 , 0x1f10000000000000
  , 0x1680000000000000 , 0x1730000000000000 , 0x15e0000000000000 , 0x1450000000000000
  , 0x1040000000000000 , 0x11f0000000000000 , 0x1320000000000000 , 0x1290000000000000
  , 0x3600000000000000 , 0x37b0000000000000 , 0x3560000000000000 , 0x34d0000000000000
  , 0x30c0000000000000 , 0x3170000000000000 , 0x33a0000000000000 , 0x3210000000000000
  , 0x3b80000000000000 , 0x3a30000000000000 , 0x38e0000000000000 , 0x3950000000000000
  , 0x3d40000000000000 , 0x3cf0000000000000 , 0x3e20000000000000 , 0x3f90000000000000
  , 0x2d00000000000000 , 0x2cb0000000000000 , 0x2e60000000000000 , 0x2fd0000000000000
  , 0x2bc0000000000000 , 0x2a70000000000000 , 0x28a0000000000000 , 0x2910000000000000
  , 0x2080000000000000 , 0x2130000000000000 , 0x23e0000000000000 , 0x2250000000000000
  , 0x2640000000000000 , 0x27f0000000000000 , 0x2520000000000000 , 0x2490000000000000
  , 0x6c00000000000000 , 0x6db0000000000000 , 0x6f60000000000000 , 0x6ed0000000000000
  , 0x6ac0000000000000 , 0x6b70000000000000 , 0x69a0000000000000 , 0x6810000000000000
  , 0x6180000000000000 , 0x6030000000000000 , 0x62e0000000000000 , 0x6350000000000000
  , 0x6740000000000000 , 0x66f0000000000000 , 0x6420000000000000 , 0x6590000000000000
  , 0x7700000000000000 , 0x76b0000000000000 , 0x7460000000000000 , 0x75d0000000000000
  , 0x71c0000000000000 , 0x7070000000000000 , 0x72a0000000000000 , 0x7310000000000000
  , 0x7a80000000000000 , 0x7b30000000000000 , 0x79e0000000000000 , 0x7850000000000000
  , 0x7c40000000000000 , 0x7df0000000000000 , 0x7f20000000000000 , 0x7e90000000000000
  , 0x5a00000000000000 , 0x5bb0000000000000 , 0x5960000000000000 , 0x58d0000000000000
  , 0x5cc0000000000000 , 0x5d70000000000000 , 0x5fa0000000000000 , 0x5e10000000000000
  , 0x5780000000000000 , 0x5630000000000000 , 0x54e0000000000000 , 0x5550000000000000
  , 0x5140000000000000 , 0x50f0000000000000 , 0x5220000000000000 , 0x5390000000000000
  , 0x4100000000000000 , 0x40b0000000000000 , 0x4260000000000000 , 0x43d0000000000000
  , 0x47c0000000000000 , 0x4670000000000000 , 0x44a0000000000000 , 0x4510000000000000
  , 0x4c80000000000000 , 0x4d30000000000000 , 0x4fe0000000000000 , 0x4e50000000000000
  , 0x4a40000000000000 , 0x4bf0000000000000 , 0x4920000000000000 , 0x4890000000000000
  , 0xd800000000000000 , 0xd9b0000000000000 , 0xdb60000000000000 , 0xdad0000000000000
  , 0xdec0000000000000 , 0xdf70000000000000 , 0xdda0000000000000 , 0xdc10000000000000
  , 0xd580000000000000 , 0xd430000000000000 , 0xd6e0000000000000 , 0xd750000000000000
  , 0xd340000000000000 , 0xd2f0000000000000 , 0xd020000000000000 , 0xd190000000000000
  , 0xc300000000000000 , 0xc2b0000000000000 , 0xc060000000000000 , 0xc1d0000000000000
  , 0xc5c0000000000000 , 0xc470000000000000 , 0xc6a0000000000000 , 0xc710000000000000
  , 0xce80000000000000 , 0xcf30000000000000 , 0xcde0000000000000 , 0xcc50000000000000
  , 0xc840000000000000 , 0xc9f0000000000000 , 0xcb20000000000000 , 0xca90000000000000
  , 0xee00000000000000 , 0xefb0000000000000 , 0xed60000000000000 , 0xecd0000000000000
  , 0xe8c0000000000000 , 0xe970000000000000 , 0xeba0000000000000 , 0xea10000000000000
  , 0xe380000000000000 , 0xe230000000000000 , 0xe0e0000000000000 , 0xe150000000000000
  , 0xe540000000000000 , 0xe4f0000000000000 , 0xe620000000000000 , 0xe790000000000000
  , 0xf500000000000000 , 0xf4b0000000000000 , 0xf660000000000000 , 0xf7d0000000000000
  , 0xf3c0000000000000 , 0xf270000000000000 , 0xf0a0000000000000 , 0xf110000000000000
  , 0xf880000000000000 , 0xf930000000000000 , 0xfbe0000000000000 , 0xfa50000000000000
  , 0xfe40000000000000 , 0xfff0000000000000 , 0xfd20000000000000 , 0xfc90000000000000
  , 0xb400000000000000 , 0xb5b0000000000000 , 0xb760000000000000 , 0xb6d0000000000000
  , 0xb2c0000000000000 , 0xb370000000000000 , 0xb1a0000000000000 , 0xb010000000000000
  , 0xb980000000000000 , 0xb830000000000000 , 0xbae0000000000000 , 0xbb50000000000000
  , 0xbf40000000000000 , 0xbef0000000000000 , 0xbc20000000000000 , 0xbd90000000000000
  , 0xaf00000000000000 , 0xaeb0000000000000 , 0xac60000000000000 , 0xadd0000000000000
  , 0xa9c0000000000000 , 0xa870000000000000 , 0xaaa0000000000000 , 0xab10000000000000
  , 0xa280000000000000 , 0xa330000000000000 , 0xa1e0000000000000 , 0xa050000000000000
  , 0xa440000000000000 , 0xa5f0000000000000 , 0xa720000000000000 , 0xa690000000000000
  , 0x8200000000000000 , 0x83b0000000000000 , 0x8160000000000000 , 0x80d0000000000000
  , 0x84c0000000000000 , 0x8570000000000000 , 0x87a0000000000000 , 0x8610000000000000
  , 0x8f80000000000000 , 0x8e30000000000000 , 0x8ce0000000000000 , 0x8d50000000000000
  , 0x8940000000000000 , 0x88f0000000000000 , 0x8a20000000000000 , 0x8b90000000000000
  , 0x9900000000000000 , 0x98b0000000000000 , 0x9a60000000000000 , 0x9bd0000000000000
  , 0x9fc0000000000000 , 0x9e70000000000000 , 0x9ca0000000000000 , 0x9d10000000000000
  , 0x9480000000000000 , 0x9530000000000000 , 0x97e0000000000000 , 0x9650000000000000
  , 0x9240000000000000 , 0x93f0000000000000 , 0x9120000000000000 , 0x9090000000000000
  ]