/
Internal.hs
1473 lines (1322 loc) · 51 KB
/
Internal.hs
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{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE CPP #-}
{-# LANGUAGE DefaultSignatures #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE GHCForeignImportPrim #-}
{-# LANGUAGE GeneralizedNewtypeDeriving #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE ScopedTypeVariables #-}
{-# LANGUAGE Trustworthy #-}
{-# LANGUAGE TypeOperators #-}
{-# LANGUAGE UnboxedTuples #-}
{-# LANGUAGE UndecidableInstances #-}
{-# LANGUAGE UnliftedFFITypes #-}
#if __GLASGOW_HASKELL__ >= 800
{-# LANGUAGE TypeFamilyDependencies #-}
#else
{-# LANGUAGE TypeFamilies #-}
#endif
{-# OPTIONS_HADDOCK hide, not-home #-}
-- |
-- Module : System.Random.Internal
-- Copyright : (c) The University of Glasgow 2001
-- License : BSD-style (see the file LICENSE in the 'random' repository)
-- Maintainer : libraries@haskell.org
-- Stability : stable
--
-- This library deals with the common task of pseudo-random number generation.
module System.Random.Internal
(-- * Pure and monadic pseudo-random number generator interfaces
RandomGen(..)
, StatefulGen(..)
, FrozenGen(..)
-- ** Standard pseudo-random number generator
, StdGen(..)
, mkStdGen
-- * Monadic adapters for pure pseudo-random number generators
-- ** Pure adapter
, StateGen(..)
, StateGenM(..)
, splitGen
, runStateGen
, runStateGen_
, runStateGenT
, runStateGenT_
, runStateGenST
-- * Pseudo-random values of various types
, Uniform(..)
, uniformViaFiniteM
, UniformRange(..)
, uniformByteStringM
, uniformDouble01M
, uniformDoublePositive01M
, uniformFloat01M
, uniformFloatPositive01M
, uniformEnumM
, uniformEnumRM
-- * Generators for sequences of pseudo-random bytes
, genShortByteStringIO
, genShortByteStringST
) where
import Control.Arrow
import Control.DeepSeq (NFData)
import Control.Monad (when)
import Control.Monad.Cont (ContT, runContT)
import Control.Monad.IO.Class (MonadIO(..))
import Control.Monad.ST
import Control.Monad.ST.Unsafe
import Control.Monad.State.Strict (StateT(..), State, MonadState(..), runState)
import Control.Monad.Trans (lift)
import Data.Bits
import Data.ByteString.Builder.Prim (word64LE)
import Data.ByteString.Builder.Prim.Internal (runF)
import Data.ByteString.Short.Internal (ShortByteString(SBS), fromShort)
import Data.Int
import Data.Word
import Foreign.C.Types
import Foreign.Ptr (plusPtr)
import Foreign.Storable (Storable(pokeByteOff))
import GHC.Exts
import GHC.Generics
import GHC.IO (IO(..))
import GHC.Word
import Numeric.Natural (Natural)
import System.IO.Unsafe (unsafePerformIO)
import System.Random.GFinite (Cardinality(..), GFinite(..))
import qualified System.Random.SplitMix as SM
import qualified System.Random.SplitMix32 as SM32
#if __GLASGOW_HASKELL__ >= 800
import Data.Kind
#endif
#if __GLASGOW_HASKELL__ >= 802
import Data.ByteString.Internal (ByteString(PS))
import GHC.ForeignPtr
#else
import Data.ByteString (ByteString)
#endif
-- | 'RandomGen' is an interface to pure pseudo-random number generators.
--
-- 'StdGen' is the standard 'RandomGen' instance provided by this library.
{-# DEPRECATED next "No longer used" #-}
{-# DEPRECATED genRange "No longer used" #-}
class RandomGen g where
{-# MINIMAL split,(genWord32|genWord64|(next,genRange)) #-}
-- | Returns an 'Int' that is uniformly distributed over the range returned by
-- 'genRange' (including both end points), and a new generator. Using 'next'
-- is inefficient as all operations go via 'Integer'. See
-- [here](https://alexey.kuleshevi.ch/blog/2019/12/21/random-benchmarks) for
-- more details. It is thus deprecated.
next :: g -> (Int, g)
next g = runStateGen g (uniformRM (genRange g))
-- | Returns a 'Word8' that is uniformly distributed over the entire 'Word8'
-- range.
--
-- @since 1.2.0
genWord8 :: g -> (Word8, g)
genWord8 = first fromIntegral . genWord32
{-# INLINE genWord8 #-}
-- | Returns a 'Word16' that is uniformly distributed over the entire 'Word16'
-- range.
--
-- @since 1.2.0
genWord16 :: g -> (Word16, g)
genWord16 = first fromIntegral . genWord32
{-# INLINE genWord16 #-}
-- | Returns a 'Word32' that is uniformly distributed over the entire 'Word32'
-- range.
--
-- @since 1.2.0
genWord32 :: g -> (Word32, g)
genWord32 = randomIvalIntegral (minBound, maxBound)
-- Once `next` is removed, this implementation should be used instead:
-- first fromIntegral . genWord64
{-# INLINE genWord32 #-}
-- | Returns a 'Word64' that is uniformly distributed over the entire 'Word64'
-- range.
--
-- @since 1.2.0
genWord64 :: g -> (Word64, g)
genWord64 g =
case genWord32 g of
(l32, g') ->
case genWord32 g' of
(h32, g'') ->
((fromIntegral h32 `shiftL` 32) .|. fromIntegral l32, g'')
{-# INLINE genWord64 #-}
-- | @genWord32R upperBound g@ returns a 'Word32' that is uniformly
-- distributed over the range @[0, upperBound]@.
--
-- @since 1.2.0
genWord32R :: Word32 -> g -> (Word32, g)
genWord32R m g = runStateGen g (unbiasedWordMult32 m)
{-# INLINE genWord32R #-}
-- | @genWord64R upperBound g@ returns a 'Word64' that is uniformly
-- distributed over the range @[0, upperBound]@.
--
-- @since 1.2.0
genWord64R :: Word64 -> g -> (Word64, g)
genWord64R m g = runStateGen g (unsignedBitmaskWithRejectionM uniformWord64 m)
{-# INLINE genWord64R #-}
-- | @genShortByteString n g@ returns a 'ShortByteString' of length @n@
-- filled with pseudo-random bytes.
--
-- @since 1.2.0
genShortByteString :: Int -> g -> (ShortByteString, g)
genShortByteString n g =
unsafePerformIO $ runStateGenT g (genShortByteStringIO n . uniformWord64)
{-# INLINE genShortByteString #-}
-- | Yields the range of values returned by 'next'.
--
-- It is required that:
--
-- * If @(a, b) = 'genRange' g@, then @a < b@.
-- * 'genRange' must not examine its argument so the value it returns is
-- determined only by the instance of 'RandomGen'.
--
-- The default definition spans the full range of 'Int'.
genRange :: g -> (Int, Int)
genRange _ = (minBound, maxBound)
-- | Returns two distinct pseudo-random number generators.
--
-- Implementations should take care to ensure that the resulting generators
-- are not correlated. Some pseudo-random number generators are not
-- splittable. In that case, the 'split' implementation should fail with a
-- descriptive 'error' message.
split :: g -> (g, g)
-- | 'StatefulGen' is an interface to monadic pseudo-random number generators.
class Monad m => StatefulGen g m where
{-# MINIMAL (uniformWord32|uniformWord64) #-}
-- | @uniformWord32R upperBound g@ generates a 'Word32' that is uniformly
-- distributed over the range @[0, upperBound]@.
--
-- @since 1.2.0
uniformWord32R :: Word32 -> g -> m Word32
uniformWord32R = unsignedBitmaskWithRejectionM uniformWord32
{-# INLINE uniformWord32R #-}
-- | @uniformWord64R upperBound g@ generates a 'Word64' that is uniformly
-- distributed over the range @[0, upperBound]@.
--
-- @since 1.2.0
uniformWord64R :: Word64 -> g -> m Word64
uniformWord64R = unsignedBitmaskWithRejectionM uniformWord64
{-# INLINE uniformWord64R #-}
-- | Generates a 'Word8' that is uniformly distributed over the entire 'Word8'
-- range.
--
-- The default implementation extracts a 'Word8' from 'uniformWord32'.
--
-- @since 1.2.0
uniformWord8 :: g -> m Word8
uniformWord8 = fmap fromIntegral . uniformWord32
{-# INLINE uniformWord8 #-}
-- | Generates a 'Word16' that is uniformly distributed over the entire
-- 'Word16' range.
--
-- The default implementation extracts a 'Word16' from 'uniformWord32'.
--
-- @since 1.2.0
uniformWord16 :: g -> m Word16
uniformWord16 = fmap fromIntegral . uniformWord32
{-# INLINE uniformWord16 #-}
-- | Generates a 'Word32' that is uniformly distributed over the entire
-- 'Word32' range.
--
-- The default implementation extracts a 'Word32' from 'uniformWord64'.
--
-- @since 1.2.0
uniformWord32 :: g -> m Word32
uniformWord32 = fmap fromIntegral . uniformWord64
{-# INLINE uniformWord32 #-}
-- | Generates a 'Word64' that is uniformly distributed over the entire
-- 'Word64' range.
--
-- The default implementation combines two 'Word32' from 'uniformWord32' into
-- one 'Word64'.
--
-- @since 1.2.0
uniformWord64 :: g -> m Word64
uniformWord64 g = do
l32 <- uniformWord32 g
h32 <- uniformWord32 g
pure (shiftL (fromIntegral h32) 32 .|. fromIntegral l32)
{-# INLINE uniformWord64 #-}
-- | @uniformShortByteString n g@ generates a 'ShortByteString' of length @n@
-- filled with pseudo-random bytes.
--
-- @since 1.2.0
uniformShortByteString :: Int -> g -> m ShortByteString
default uniformShortByteString :: MonadIO m => Int -> g -> m ShortByteString
uniformShortByteString n = genShortByteStringIO n . uniformWord64
{-# INLINE uniformShortByteString #-}
-- | This class is designed for stateful pseudo-random number generators that
-- can be saved as and restored from an immutable data type.
--
-- @since 1.2.0
class StatefulGen (MutableGen f m) m => FrozenGen f m where
-- | Represents the state of the pseudo-random number generator for use with
-- 'thawGen' and 'freezeGen'.
--
-- @since 1.2.0
#if __GLASGOW_HASKELL__ >= 800
type MutableGen f m = (g :: Type) | g -> f
#else
type MutableGen f m :: *
#endif
-- | Saves the state of the pseudo-random number generator as a frozen seed.
--
-- @since 1.2.0
freezeGen :: MutableGen f m -> m f
-- | Restores the pseudo-random number generator from its frozen seed.
--
-- @since 1.2.0
thawGen :: f -> m (MutableGen f m)
data MBA s = MBA (MutableByteArray# s)
-- | Efficiently generates a sequence of pseudo-random bytes in a platform
-- independent manner.
--
-- @since 1.2.0
genShortByteStringIO ::
MonadIO m
=> Int -- ^ Number of bytes to generate
-> m Word64 -- ^ IO action that can generate 8 random bytes at a time
-> m ShortByteString
genShortByteStringIO n0 gen64 = do
let !n@(I# n#) = max 0 n0
!n64 = n `quot` 8
!nrem64 = n `rem` 8
MBA mba# <-
liftIO $
IO $ \s# ->
case newPinnedByteArray# n# s# of
(# s'#, mba# #) -> (# s'#, MBA mba# #)
let go i ptr
| i < n64 = do
w64 <- gen64
-- Writing 8 bytes at a time in a Little-endian order gives us
-- platform portability
liftIO $ runF word64LE w64 ptr
go (i + 1) (ptr `plusPtr` 8)
| otherwise = return ptr
ptr <- go 0 (Ptr (byteArrayContents# (unsafeCoerce# mba#)))
when (nrem64 > 0) $ do
w64 <- gen64
-- In order to not mess up the byte order we write generated Word64 into a
-- temporary pointer and then copy only the missing bytes over to the array.
-- It is tempting to simply generate as many bytes as we still need using
-- smaller generators (eg. uniformWord8), but that would result in
-- inconsistent tail when total length is slightly varied.
liftIO $ do
let goRem64 z i =
when (i < nrem64) $ do
pokeByteOff ptr i (fromIntegral z :: Word8)
goRem64 (z `shiftR` 8) (i + 1)
goRem64 w64 0
liftIO $
IO $ \s# ->
case unsafeFreezeByteArray# mba# s# of
(# s'#, ba# #) -> (# s'#, SBS ba# #)
{-# INLINE genShortByteStringIO #-}
-- | Same as 'genShortByteStringIO', but runs in 'ST'.
--
-- @since 1.2.0
genShortByteStringST :: Int -> ST s Word64 -> ST s ShortByteString
genShortByteStringST n action =
unsafeIOToST (genShortByteStringIO n (unsafeSTToIO action))
{-# INLINE genShortByteStringST #-}
-- | Generates a pseudo-random 'ByteString' of the specified size.
--
-- @since 1.2.0
uniformByteStringM :: StatefulGen g m => Int -> g -> m ByteString
uniformByteStringM n g = do
ba <- uniformShortByteString n g
pure $
#if __GLASGOW_HASKELL__ < 802
fromShort ba
#else
let !(SBS ba#) = ba in
if isTrue# (isByteArrayPinned# ba#)
then pinnedByteArrayToByteString ba#
else fromShort ba
{-# INLINE uniformByteStringM #-}
pinnedByteArrayToByteString :: ByteArray# -> ByteString
pinnedByteArrayToByteString ba# =
PS (pinnedByteArrayToForeignPtr ba#) 0 (I# (sizeofByteArray# ba#))
{-# INLINE pinnedByteArrayToByteString #-}
pinnedByteArrayToForeignPtr :: ByteArray# -> ForeignPtr a
pinnedByteArrayToForeignPtr ba# =
ForeignPtr (byteArrayContents# ba#) (PlainPtr (unsafeCoerce# ba#))
{-# INLINE pinnedByteArrayToForeignPtr #-}
#endif
-- | Opaque data type that carries the type of a pure pseudo-random number
-- generator.
--
-- @since 1.2.0
data StateGenM g = StateGenM
-- | Wrapper for pure state gen, which acts as an immutable seed for the corresponding
-- stateful generator `StateGenM`
--
-- @since 1.2.0
newtype StateGen g = StateGen { unStateGen :: g }
deriving (Eq, Ord, Show, RandomGen, Storable, NFData)
instance (RandomGen g, MonadState g m) => StatefulGen (StateGenM g) m where
uniformWord32R r _ = state (genWord32R r)
{-# INLINE uniformWord32R #-}
uniformWord64R r _ = state (genWord64R r)
{-# INLINE uniformWord64R #-}
uniformWord8 _ = state genWord8
{-# INLINE uniformWord8 #-}
uniformWord16 _ = state genWord16
{-# INLINE uniformWord16 #-}
uniformWord32 _ = state genWord32
{-# INLINE uniformWord32 #-}
uniformWord64 _ = state genWord64
{-# INLINE uniformWord64 #-}
uniformShortByteString n _ = state (genShortByteString n)
{-# INLINE uniformShortByteString #-}
instance (RandomGen g, MonadState g m) => FrozenGen (StateGen g) m where
type MutableGen (StateGen g) m = StateGenM g
freezeGen _ = fmap StateGen get
thawGen (StateGen g) = StateGenM <$ put g
-- | Splits a pseudo-random number generator into two. Updates the state with
-- one of the resulting generators and returns the other.
--
-- @since 1.2.0
splitGen :: (MonadState g m, RandomGen g) => m g
splitGen = state split
{-# INLINE splitGen #-}
-- | Runs a monadic generating action in the `State` monad using a pure
-- pseudo-random number generator.
--
-- ====__Examples__
--
-- >>> import System.Random.Stateful
-- >>> let pureGen = mkStdGen 137
-- >>> runStateGen pureGen randomM :: (Int, StdGen)
-- (7879794327570578227,StdGen {unStdGen = SMGen 11285859549637045894 7641485672361121627})
--
-- @since 1.2.0
runStateGen :: RandomGen g => g -> (StateGenM g -> State g a) -> (a, g)
runStateGen g f = runState (f StateGenM) g
{-# INLINE runStateGen #-}
-- | Runs a monadic generating action in the `State` monad using a pure
-- pseudo-random number generator. Returns only the resulting pseudo-random
-- value.
--
-- ====__Examples__
--
-- >>> import System.Random.Stateful
-- >>> let pureGen = mkStdGen 137
-- >>> runStateGen_ pureGen randomM :: Int
-- 7879794327570578227
--
-- @since 1.2.0
runStateGen_ :: RandomGen g => g -> (StateGenM g -> State g a) -> a
runStateGen_ g = fst . runStateGen g
{-# INLINE runStateGen_ #-}
-- | Runs a monadic generating action in the `StateT` monad using a pure
-- pseudo-random number generator.
--
-- ====__Examples__
--
-- >>> import System.Random.Stateful
-- >>> let pureGen = mkStdGen 137
-- >>> runStateGenT pureGen randomM :: IO (Int, StdGen)
-- (7879794327570578227,StdGen {unStdGen = SMGen 11285859549637045894 7641485672361121627})
--
-- @since 1.2.0
runStateGenT :: RandomGen g => g -> (StateGenM g -> StateT g m a) -> m (a, g)
runStateGenT g f = runStateT (f StateGenM) g
{-# INLINE runStateGenT #-}
-- | Runs a monadic generating action in the `StateT` monad using a pure
-- pseudo-random number generator. Returns only the resulting pseudo-random
-- value.
--
-- ====__Examples__
--
-- >>> import System.Random.Stateful
-- >>> let pureGen = mkStdGen 137
-- >>> runStateGenT_ pureGen randomM :: IO Int
-- 7879794327570578227
--
-- @since 1.2.0
runStateGenT_ :: (RandomGen g, Functor f) => g -> (StateGenM g -> StateT g f a) -> f a
runStateGenT_ g = fmap fst . runStateGenT g
{-# INLINE runStateGenT_ #-}
-- | Runs a monadic generating action in the `ST` monad using a pure
-- pseudo-random number generator.
--
-- @since 1.2.0
runStateGenST :: RandomGen g => g -> (forall s . StateGenM g -> StateT g (ST s) a) -> (a, g)
runStateGenST g action = runST $ runStateGenT g action
{-# INLINE runStateGenST #-}
-- | The standard pseudo-random number generator.
newtype StdGen = StdGen { unStdGen :: SM.SMGen }
deriving (Show, RandomGen, NFData)
instance Eq StdGen where
StdGen x1 == StdGen x2 = SM.unseedSMGen x1 == SM.unseedSMGen x2
instance RandomGen SM.SMGen where
next = SM.nextInt
{-# INLINE next #-}
genWord32 = SM.nextWord32
{-# INLINE genWord32 #-}
genWord64 = SM.nextWord64
{-# INLINE genWord64 #-}
split = SM.splitSMGen
{-# INLINE split #-}
instance RandomGen SM32.SMGen where
next = SM32.nextInt
{-# INLINE next #-}
genWord32 = SM32.nextWord32
{-# INLINE genWord32 #-}
genWord64 = SM32.nextWord64
{-# INLINE genWord64 #-}
split = SM32.splitSMGen
{-# INLINE split #-}
-- | Constructs a 'StdGen' deterministically.
mkStdGen :: Int -> StdGen
mkStdGen = StdGen . SM.mkSMGen . fromIntegral
-- | The class of types for which a uniformly distributed value can be drawn
-- from all possible values of the type.
--
-- @since 1.2.0
class Uniform a where
-- | Generates a value uniformly distributed over all possible values of that
-- type.
--
-- There is a default implementation via 'Generic':
--
-- >>> :set -XDeriveGeneric -XDeriveAnyClass
-- >>> import GHC.Generics (Generic)
-- >>> import System.Random.Stateful
-- >>> data MyBool = MyTrue | MyFalse deriving (Show, Generic, Finite, Uniform)
-- >>> data Action = Code MyBool | Eat (Maybe Bool) | Sleep deriving (Show, Generic, Finite, Uniform)
-- >>> gen <- newIOGenM (mkStdGen 42)
-- >>> uniformListM 10 gen :: IO [Action]
-- [Code MyTrue,Code MyTrue,Eat Nothing,Code MyFalse,Eat (Just False),Eat (Just True),Eat Nothing,Eat (Just False),Sleep,Code MyFalse]
--
-- @since 1.2.0
uniformM :: StatefulGen g m => g -> m a
default uniformM :: (StatefulGen g m, Generic a, GUniform (Rep a)) => g -> m a
uniformM = fmap to . (`runContT` pure) . guniformM
{-# INLINE uniformM #-}
-- | Default implementation of 'Uniform' type class for 'Generic' data.
-- It's important to use 'ContT', because without it 'fmap' and '>>=' remain
-- polymorphic too long and GHC fails to inline or specialize it, ending up
-- building full 'Rep' a structure in memory. 'ContT'
-- makes 'fmap' and '>>=' used in 'guniformM' monomorphic, so GHC is able to
-- specialize 'Generic' instance reasonably close to a handwritten one.
class GUniform f where
guniformM :: StatefulGen g m => g -> ContT r m (f a)
instance GUniform f => GUniform (M1 i c f) where
guniformM = fmap M1 . guniformM
{-# INLINE guniformM #-}
instance Uniform a => GUniform (K1 i a) where
guniformM = fmap K1 . lift . uniformM
{-# INLINE guniformM #-}
instance GUniform U1 where
guniformM = const $ return U1
{-# INLINE guniformM #-}
instance (GUniform f, GUniform g) => GUniform (f :*: g) where
guniformM g = (:*:) <$> guniformM g <*> guniformM g
{-# INLINE guniformM #-}
instance (GFinite f, GFinite g) => GUniform (f :+: g) where
guniformM = lift . finiteUniformM
{-# INLINE guniformM #-}
finiteUniformM :: forall g m f a. (StatefulGen g m, GFinite f) => g -> m (f a)
finiteUniformM = fmap toGFinite . case gcardinality (proxy# :: Proxy# f) of
Shift n
| n <= 64 -> fmap toInteger . unsignedBitmaskWithRejectionM uniformWord64 (bit n - 1)
| otherwise -> boundedByPowerOf2ExclusiveIntegralM n
Card n
| n <= bit 64 -> fmap toInteger . unsignedBitmaskWithRejectionM uniformWord64 (fromInteger n - 1)
| otherwise -> boundedExclusiveIntegralM n
{-# INLINE finiteUniformM #-}
-- | A definition of 'Uniform' for 'System.Random.Finite' types.
-- If your data has several fields of sub-'Word' cardinality,
-- this instance may be more efficient than one, derived via 'Generic' and 'GUniform'.
--
-- >>> :set -XDeriveGeneric -XDeriveAnyClass
-- >>> import GHC.Generics (Generic)
-- >>> import System.Random.Stateful
-- >>> data Triple = Triple Word8 Word8 Word8 deriving (Show, Generic, Finite)
-- >>> instance Uniform Triple where uniformM = uniformViaFiniteM
-- >>> gen <- newIOGenM (mkStdGen 42)
-- >>> uniformListM 5 gen :: IO [Triple]
-- [Triple 60 226 48,Triple 234 194 151,Triple 112 96 95,Triple 51 251 15,Triple 6 0 208]
--
uniformViaFiniteM :: (StatefulGen g m, Generic a, GFinite (Rep a)) => g -> m a
uniformViaFiniteM = fmap to . finiteUniformM
{-# INLINE uniformViaFiniteM #-}
-- | The class of types for which a uniformly distributed value can be drawn
-- from a range.
--
-- @since 1.2.0
class UniformRange a where
-- | Generates a value uniformly distributed over the provided range, which
-- is interpreted as inclusive in the lower and upper bound.
--
-- * @uniformRM (1 :: Int, 4 :: Int)@ generates values uniformly from the
-- set \(\{1,2,3,4\}\)
--
-- * @uniformRM (1 :: Float, 4 :: Float)@ generates values uniformly from
-- the set \(\{x\;|\;1 \le x \le 4\}\)
--
-- The following law should hold to make the function always defined:
--
-- > uniformRM (a, b) = uniformRM (b, a)
--
-- The range is understood as defined by means of 'isInRange', so
--
-- > isInRange (a, b) <$> uniformRM (a, b) gen == pure True
--
-- but beware of
-- [floating point number caveats](System-Random-Stateful.html#fpcaveats).
--
-- There is a default implementation via 'Generic':
--
-- >>> :set -XDeriveGeneric -XDeriveAnyClass
-- >>> import GHC.Generics (Generic)
-- >>> import Data.Word (Word8)
-- >>> import System.Random.Stateful
-- >>> gen <- newIOGenM (mkStdGen 42)
-- >>> data Tuple = Tuple Bool Word8 deriving (Show, Generic, UniformRange)
-- >>> Control.Monad.replicateM 10 (uniformRM (Tuple False 100, Tuple True 150) gen)
-- [Tuple False 102,Tuple True 118,Tuple False 115,Tuple True 113,Tuple True 126,Tuple False 127,Tuple True 130,Tuple False 113,Tuple False 150,Tuple False 125]
--
-- @since 1.2.0
uniformRM :: StatefulGen g m => (a, a) -> g -> m a
-- | A notion of (inclusive) ranges prescribed to @a@.
--
-- Ranges are symmetric:
--
-- > isInRange (lo, hi) x == isInRange (hi, lo) x
--
-- Ranges include their endpoints:
--
-- > isInRange (lo, hi) lo == True
--
-- When endpoints coincide, there is nothing else:
--
-- > isInRange (x, x) y == x == y
--
-- Endpoints are endpoints:
--
-- > isInRange (lo, hi) x ==>
-- > isInRange (lo, x) hi == x == hi
--
-- Ranges are transitive relations:
--
-- > isInRange (lo, hi) lo' && isInRange (lo, hi) hi' && isInRange (lo', hi') x
-- > ==> isInRange (lo, hi) x
--
-- There is a default implementation of 'isInRange' via 'Generic'.
--
-- @since 1.3.0
isInRange :: (a, a) -> a -> Bool
default uniformRM :: (StatefulGen g m, Generic a, GUniformRange (Rep a)) => (a, a) -> g -> m a
uniformRM (a, b) = fmap to . (`runContT` pure) . guniformRM (from a, from b)
{-# INLINE uniformRM #-}
default isInRange :: (Generic a, GUniformRange (Rep a)) => (a, a) -> a -> Bool
isInRange (a, b) x = gisInRange (from a, from b) (from x)
{-# INLINE isInRange #-}
class GUniformRange f where
guniformRM :: StatefulGen g m => (f a, f a) -> g -> ContT r m (f a)
gisInRange :: (f a, f a) -> f a -> Bool
instance GUniformRange f => GUniformRange (M1 i c f) where
guniformRM (M1 a, M1 b) = fmap M1 . guniformRM (a, b)
{-# INLINE guniformRM #-}
gisInRange (M1 a, M1 b) (M1 x) = gisInRange (a, b) x
instance UniformRange a => GUniformRange (K1 i a) where
guniformRM (K1 a, K1 b) = fmap K1 . lift . uniformRM (a, b)
{-# INLINE guniformRM #-}
gisInRange (K1 a, K1 b) (K1 x) = isInRange (a, b) x
instance GUniformRange U1 where
guniformRM = const $ const $ return U1
{-# INLINE guniformRM #-}
gisInRange = const $ const True
instance (GUniformRange f, GUniformRange g) => GUniformRange (f :*: g) where
guniformRM (x1 :*: y1, x2 :*: y2) g =
(:*:) <$> guniformRM (x1, x2) g <*> guniformRM (y1, y2) g
{-# INLINE guniformRM #-}
gisInRange (x1 :*: y1, x2 :*: y2) (x3 :*: y3) =
gisInRange (x1, x2) x3 && gisInRange (y1, y2) y3
isInRangeOrd :: Ord a => (a, a) -> a -> Bool
isInRangeOrd (a, b) x = min a b <= x && x <= max a b
instance UniformRange Integer where
uniformRM = uniformIntegralM
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance UniformRange Natural where
uniformRM = uniformIntegralM
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Int8 where
uniformM = fmap (fromIntegral :: Word8 -> Int8) . uniformWord8
{-# INLINE uniformM #-}
instance UniformRange Int8 where
uniformRM = signedBitmaskWithRejectionRM (fromIntegral :: Int8 -> Word8) fromIntegral
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Int16 where
uniformM = fmap (fromIntegral :: Word16 -> Int16) . uniformWord16
{-# INLINE uniformM #-}
instance UniformRange Int16 where
uniformRM = signedBitmaskWithRejectionRM (fromIntegral :: Int16 -> Word16) fromIntegral
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Int32 where
uniformM = fmap (fromIntegral :: Word32 -> Int32) . uniformWord32
{-# INLINE uniformM #-}
instance UniformRange Int32 where
uniformRM = signedBitmaskWithRejectionRM (fromIntegral :: Int32 -> Word32) fromIntegral
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Int64 where
uniformM = fmap (fromIntegral :: Word64 -> Int64) . uniformWord64
{-# INLINE uniformM #-}
instance UniformRange Int64 where
uniformRM = signedBitmaskWithRejectionRM (fromIntegral :: Int64 -> Word64) fromIntegral
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
wordSizeInBits :: Int
wordSizeInBits = finiteBitSize (0 :: Word)
instance Uniform Int where
uniformM
| wordSizeInBits == 64 =
fmap (fromIntegral :: Word64 -> Int) . uniformWord64
| otherwise =
fmap (fromIntegral :: Word32 -> Int) . uniformWord32
{-# INLINE uniformM #-}
instance UniformRange Int where
uniformRM = signedBitmaskWithRejectionRM (fromIntegral :: Int -> Word) fromIntegral
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Word where
uniformM
| wordSizeInBits == 64 =
fmap (fromIntegral :: Word64 -> Word) . uniformWord64
| otherwise =
fmap (fromIntegral :: Word32 -> Word) . uniformWord32
{-# INLINE uniformM #-}
instance UniformRange Word where
uniformRM = unsignedBitmaskWithRejectionRM
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Word8 where
uniformM = uniformWord8
{-# INLINE uniformM #-}
instance UniformRange Word8 where
uniformRM = unbiasedWordMult32RM
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Word16 where
uniformM = uniformWord16
{-# INLINE uniformM #-}
instance UniformRange Word16 where
uniformRM = unbiasedWordMult32RM
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Word32 where
uniformM = uniformWord32
{-# INLINE uniformM #-}
instance UniformRange Word32 where
uniformRM = unbiasedWordMult32RM
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform Word64 where
uniformM = uniformWord64
{-# INLINE uniformM #-}
instance UniformRange Word64 where
uniformRM = unsignedBitmaskWithRejectionRM
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
#if __GLASGOW_HASKELL__ >= 802
instance Uniform CBool where
uniformM = fmap CBool . uniformM
{-# INLINE uniformM #-}
instance UniformRange CBool where
uniformRM (CBool b, CBool t) = fmap CBool . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
#endif
instance Uniform CChar where
uniformM = fmap CChar . uniformM
{-# INLINE uniformM #-}
instance UniformRange CChar where
uniformRM (CChar b, CChar t) = fmap CChar . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CSChar where
uniformM = fmap CSChar . uniformM
{-# INLINE uniformM #-}
instance UniformRange CSChar where
uniformRM (CSChar b, CSChar t) = fmap CSChar . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CUChar where
uniformM = fmap CUChar . uniformM
{-# INLINE uniformM #-}
instance UniformRange CUChar where
uniformRM (CUChar b, CUChar t) = fmap CUChar . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CShort where
uniformM = fmap CShort . uniformM
{-# INLINE uniformM #-}
instance UniformRange CShort where
uniformRM (CShort b, CShort t) = fmap CShort . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CUShort where
uniformM = fmap CUShort . uniformM
{-# INLINE uniformM #-}
instance UniformRange CUShort where
uniformRM (CUShort b, CUShort t) = fmap CUShort . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CInt where
uniformM = fmap CInt . uniformM
{-# INLINE uniformM #-}
instance UniformRange CInt where
uniformRM (CInt b, CInt t) = fmap CInt . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CUInt where
uniformM = fmap CUInt . uniformM
{-# INLINE uniformM #-}
instance UniformRange CUInt where
uniformRM (CUInt b, CUInt t) = fmap CUInt . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CLong where
uniformM = fmap CLong . uniformM
{-# INLINE uniformM #-}
instance UniformRange CLong where
uniformRM (CLong b, CLong t) = fmap CLong . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CULong where
uniformM = fmap CULong . uniformM
{-# INLINE uniformM #-}
instance UniformRange CULong where
uniformRM (CULong b, CULong t) = fmap CULong . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CPtrdiff where
uniformM = fmap CPtrdiff . uniformM
{-# INLINE uniformM #-}
instance UniformRange CPtrdiff where
uniformRM (CPtrdiff b, CPtrdiff t) = fmap CPtrdiff . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CSize where
uniformM = fmap CSize . uniformM
{-# INLINE uniformM #-}
instance UniformRange CSize where
uniformRM (CSize b, CSize t) = fmap CSize . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CWchar where
uniformM = fmap CWchar . uniformM
{-# INLINE uniformM #-}
instance UniformRange CWchar where
uniformRM (CWchar b, CWchar t) = fmap CWchar . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CSigAtomic where
uniformM = fmap CSigAtomic . uniformM
{-# INLINE uniformM #-}
instance UniformRange CSigAtomic where
uniformRM (CSigAtomic b, CSigAtomic t) = fmap CSigAtomic . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CLLong where
uniformM = fmap CLLong . uniformM
{-# INLINE uniformM #-}
instance UniformRange CLLong where
uniformRM (CLLong b, CLLong t) = fmap CLLong . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CULLong where
uniformM = fmap CULLong . uniformM
{-# INLINE uniformM #-}
instance UniformRange CULLong where
uniformRM (CULLong b, CULLong t) = fmap CULLong . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CIntPtr where
uniformM = fmap CIntPtr . uniformM
{-# INLINE uniformM #-}
instance UniformRange CIntPtr where
uniformRM (CIntPtr b, CIntPtr t) = fmap CIntPtr . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CUIntPtr where
uniformM = fmap CUIntPtr . uniformM
{-# INLINE uniformM #-}
instance UniformRange CUIntPtr where
uniformRM (CUIntPtr b, CUIntPtr t) = fmap CUIntPtr . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CIntMax where
uniformM = fmap CIntMax . uniformM
{-# INLINE uniformM #-}
instance UniformRange CIntMax where
uniformRM (CIntMax b, CIntMax t) = fmap CIntMax . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
instance Uniform CUIntMax where
uniformM = fmap CUIntMax . uniformM
{-# INLINE uniformM #-}
instance UniformRange CUIntMax where
uniformRM (CUIntMax b, CUIntMax t) = fmap CUIntMax . uniformRM (b, t)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
-- | See [Floating point number caveats](System-Random-Stateful.html#fpcaveats).
instance UniformRange CFloat where
uniformRM (CFloat l, CFloat h) = fmap CFloat . uniformRM (l, h)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
-- | See [Floating point number caveats](System-Random-Stateful.html#fpcaveats).
instance UniformRange CDouble where
uniformRM (CDouble l, CDouble h) = fmap CDouble . uniformRM (l, h)
{-# INLINE uniformRM #-}
isInRange = isInRangeOrd
-- The `chr#` and `ord#` are the prim functions that will be called, regardless of which
-- way you gonna do the `Char` conversion, so it is better to call them directly and