-- Hoogle documentation, generated by Haddock
-- See Hoogle, http://www.haskell.org/hoogle/


-- | High-quality splittable pseudorandom number generator
--   
--   This package contains an implementation of a high-quality splittable
--   pseudorandom number generator. The generator is based on a
--   cryptographic hash function built on top of the ThreeFish block
--   cipher. See the paper <i>Splittable Pseudorandom Number Generators
--   Using Cryptographic Hashing</i> by Claessen, Pałka for details and the
--   rationale of the design.
--   
--   The package provides the following:
--   
--   <ul>
--   <li>A splittable PRNG that implements the standard
--   <a>System.Random.RandomGen</a> class.</li>
--   <li>The generator also implements an alternative version of the
--   <a>System.Random.TF.Gen.RandomGen</a> class (exported from
--   <a>System.Random.TF.Gen</a>), which requires the generator to return
--   pseudorandom integers from the full 32-bit range, and contains an
--   n-way split function.</li>
--   <li>An alternative version of the <tt>Random</tt> class is provided,
--   which is linked to the new <tt>RandomGen</tt> class, together with
--   <tt>Random</tt> instances for some integral types.</li>
--   <li>Two functions for initialising the generator with a
--   non-deterministic seed: one using the system time, and one using the
--   <tt>/dev/urandom</tt> UNIX special file.</li>
--   </ul>
--   
--   The package uses an adapted version of the reference C implementation
--   of ThreeFish from the reference package of the Skein hash function
--   (<a>https://www.schneier.com/skein.html</a>), originally written by
--   Doug Whiting.
--   
--   Please note that even though the generator provides very high-quality
--   pseudorandom numbers, it has not been designed with cryptographic
--   applications in mind.
@package tf-random
@version 0.1

module System.Random.TF.Init

-- | Use system time create the random seed. This method of seeding may not
--   be relible.
mkSeedTime :: IO (Word64, Word64, Word64, Word64)

-- | Use the UNIX special file <tt>/dev/urandom</tt> to create the seed.
--   Inspired by <tt>random-mwc</tt>.
mkSeedUnix :: IO (Word64, Word64, Word64, Word64)


-- | This module provides the <a>TFGen</a> generator and the alternative
--   <a>RandomGen</a> class. <a>TFGen</a> also implements the standard
--   <a>RandomGen</a> class.
module System.Random.TF.Gen

-- | The generator type
data TFGen

-- | Alternative <a>RandomGen</a> class with a modified <a>next</a>
--   operation, and added <a>splitn</a> and <a>level</a> operations.
--   
--   Using the generator requires that no more than one operation is called
--   on the same generator state, as the implementation does not guarantee
--   pseudorandomness otherwise. As an exception, calling <a>splitn</a>
--   many times on the same generator state is allowed as long as the
--   'bits' argument is the same for all the calls.
class RandomGen g
next :: RandomGen g => g -> (Word32, g)
split :: RandomGen g => g -> (g, g)
splitn :: RandomGen g => g -> Int -> Word32 -> g
level :: RandomGen g => g -> g

-- | Create a generator from a random seed.
seedTFGen :: (Word64, Word64, Word64, Word64) -> TFGen
instance Show TFGenR
instance Read TFGenR
instance RandomGen TFGen
instance RandomGen TFGen
instance Read TFGen
instance Show TFGen
instance Read Hex
instance Show Hex


-- | This module defines alternative <a>Random</a> instances for common
--   integral types, which make use of the <a>RandomGen</a> class from
--   <a>System.Random.TF.Gen</a>.
module System.Random.TF.Instances
class Random a where randomRs ival g = myUnfoldr (randomR ival) g randoms g = myUnfoldr random g
randomR :: (Random a, RandomGen g) => (a, a) -> g -> (a, g)
random :: (Random a, RandomGen g) => g -> (a, g)
randomRs :: (Random a, RandomGen g) => (a, a) -> g -> [a]
randoms :: (Random a, RandomGen g) => g -> [a]
instance Random Int64
instance Random Int32
instance Random Word64
instance Random Word32
instance Random Integer
instance Random Bool
instance Random Char
instance Random Int


-- | This module exports <a>System.Random.TF.Gen</a> and
--   <a>System.Random.TF.Init</a> modules without exporting the alternative
--   <a>RandomGen</a> class from <a>System.Random.TF.Gen</a>. To use this
--   class and the <a>Random</a> instances written for it, please import
--   <a>System.Random.TF.Gen</a> and <a>System.Random.TF.Instances</a>
--   directly.
module System.Random.TF