diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,47 @@
+# fast-digits [](https://travis-ci.org/Bodigrim/fast-digits) [](https://hackage.haskell.org/package/fast-digits) [](https://matrix.hackage.haskell.org/package/fast-digits) [](http://stackage.org/lts/package/fast-digits) [](http://stackage.org/nightly/package/fast-digits)
+
+The fastest Haskell library to split integers into digits.
+It is both asymptotically (O(n1.4) vs. O(n2))
+and practically (2x-40x for typical inputs)
+faster than [Data.Digits](https://hackage.haskell.org/package/digits).
+
+Here are some benchmarks:
+
+```
+> cabal bench
+shortInt/FastDigits base 2 mean 6.429 ms ( +- 465.7 μs )
+shortInt/Data.Digits base 2 mean 50.08 ms ( +- 1.848 ms )
+
+shortInt/FastDigits base 10 mean 4.288 ms ( +- 217.1 μs )
+shortInt/Data.Digits base 10 mean 15.62 ms ( +- 540.1 μs )
+
+shortInt/FastDigits base 10^5 mean 1.142 ms ( +- 50.09 μs )
+shortInt/Data.Digits base 10^5 mean 3.962 ms ( +- 269.1 μs )
+
+shortInt/FastDigits base 10^9 mean 963.8 μs ( +- 46.13 μs )
+shortInt/Data.Digits base 10^9 mean 3.052 ms ( +- 238.5 μs )
+
+mediumInt/FastDigits base 2 mean 1.213 ms ( +- 185.0 μs )
+mediumInt/Data.Digits base 2 mean 12.41 ms ( +- 3.417 ms )
+
+mediumInt/FastDigits base 10 mean 689.3 μs ( +- 32.43 μs )
+mediumInt/Data.Digits base 10 mean 3.271 ms ( +- 137.3 μs )
+
+mediumInt/FastDigits base 10^5 mean 220.1 μs ( +- 11.30 μs )
+mediumInt/Data.Digits base 10^5 mean 711.1 μs ( +- 67.31 μs )
+
+mediumInt/FastDigits base 10^9 mean 156.0 μs ( +- 9.115 μs )
+mediumInt/Data.Digits base 10^9 mean 407.9 μs ( +- 19.58 μs )
+
+longInt/FastDigits base 2 mean 3.515 ms ( +- 189.7 μs )
+longInt/Data.Digits base 2 mean 183.2 ms ( +- 4.564 ms )
+
+longInt/FastDigits base 10 mean 2.164 ms ( +- 134.7 μs )
+longInt/Data.Digits base 10 mean 55.45 ms ( +- 946.7 μs )
+
+longInt/FastDigits base 10^5 mean 1.467 ms ( +- 60.49 μs )
+longInt/Data.Digits base 10^5 mean 11.09 ms ( +- 347.0 μs )
+
+longInt/FastDigits base 10^9 mean 1.242 ms ( +- 52.92 μs )
+longInt/Data.Digits base 10^9 mean 6.181 ms ( +- 226.1 μs )
+```
diff --git a/bench/Bench.hs b/bench/Bench.hs
--- a/bench/Bench.hs
+++ b/bench/Bench.hs
@@ -1,6 +1,6 @@
module Main where
-import Criterion.Main
+import Gauge.Main
import qualified Data.Digits as D
diff --git a/changelog.md b/changelog.md
new file mode 100644
--- /dev/null
+++ b/changelog.md
@@ -0,0 +1,15 @@
+# 0.3.0.0
+
+* Hide `Data.FastDigits.Internal`.
+
+# 0.2.1.0
+
+* Fix x32 build.
+
+# 0.2.0.0
+
+* Performance improvements.
+
+# 0.1.0.0
+
+* Initial release.
diff --git a/fast-digits.cabal b/fast-digits.cabal
--- a/fast-digits.cabal
+++ b/fast-digits.cabal
@@ -1,53 +1,75 @@
-name: fast-digits
-version: 0.2.1.0
-synopsis: The fast library for integer-to-digits conversion.
-description: Convert an integer to digits and back.
- Usually this library is twice as fast as "Data.Digits".
- For small bases and long numbers it may be up to 40 times faster.
-homepage: https://github.com/Bodigrim/fast-digits
-license: GPL-3
-license-file: LICENSE
-author: Andrew Lelechenko
-maintainer: andrew.lelechenko@gmail.com
-category: Data
-build-type: Simple
-cabal-version: >=1.10
+name: fast-digits
+version: 0.3.0.0
+license: GPL-3
+license-file: LICENSE
+maintainer: andrew.lelechenko@gmail.com
+author: Andrew Lelechenko
+homepage: https://github.com/Bodigrim/fast-digits
+synopsis: Integer-to-digits conversion.
+description:
+ Convert an integer to digits and back.
+ This library is both asymptotically (O(n^1.4) vs. O(n^2))
+ and practically (2x-40x for typical inputs)
+ faster than "Data.Digits".
+category: Data
+build-type: Simple
+cabal-version: 2.0
+extra-source-files:
+ changelog.md
+ README.md
+tested-with:
+ GHC ==7.10.3 GHC ==8.0.2 GHC ==8.2.2 GHC ==8.4.4 GHC ==8.6.5 GHC ==8.8.2
source-repository head
- type: git
+ type: git
location: git://github.com/Bodigrim/fast-digits.git
library
- exposed-modules: Data.FastDigits
- , Data.FastDigits.Internal
- build-depends: base >=4.8 && < 5
- , integer-gmp >=1.0
- hs-source-dirs: src
- default-language: Haskell2010
- ghc-options: -Wall
+ exposed-modules:
+ Data.FastDigits
+ hs-source-dirs: src
+ default-language: Haskell2010
+ ghc-options: -Wall
+ build-depends:
+ base >=4.8 && <5,
+ integer-gmp >=1.0,
+ fast-digits-internal
+library fast-digits-internal
+ exposed-modules:
+ Data.FastDigits.Internal
+ hs-source-dirs: src-internal
+ default-language: Haskell2010
+ ghc-options: -Wall
+ build-depends:
+ base >=4.8 && <5,
+ integer-gmp >=1.0
+
test-suite tests
- type: exitcode-stdio-1.0
- main-is: Tests.hs
- build-depends: base
- , tasty
- , tasty-quickcheck
- , tasty-smallcheck
- , QuickCheck
- , smallcheck
- , digits
- , fast-digits
- hs-source-dirs: tests
- default-language: Haskell2010
- ghc-options: -Wall
+ type: exitcode-stdio-1.0
+ main-is: Tests.hs
+ hs-source-dirs: tests
+ default-language: Haskell2010
+ ghc-options: -Wall
+ build-depends:
+ base,
+ tasty,
+ tasty-quickcheck,
+ tasty-smallcheck,
+ QuickCheck,
+ smallcheck,
+ digits,
+ fast-digits,
+ fast-digits-internal
benchmark bench
- type: exitcode-stdio-1.0
- main-is: Bench.hs
- hs-source-dirs: bench
- build-depends: base
- , criterion
- , digits
- , fast-digits
- default-language: Haskell2010
- ghc-options: -O2
+ type: exitcode-stdio-1.0
+ main-is: Bench.hs
+ hs-source-dirs: bench
+ default-language: Haskell2010
+ ghc-options: -O2
+ build-depends:
+ base,
+ digits,
+ fast-digits,
+ gauge
diff --git a/src-internal/Data/FastDigits/Internal.hs b/src-internal/Data/FastDigits/Internal.hs
new file mode 100644
--- /dev/null
+++ b/src-internal/Data/FastDigits/Internal.hs
@@ -0,0 +1,53 @@
+{-|
+Module : Data.FastDigits.Internal
+Copyright : (c) Andrew Lelechenko, 2015-2016
+License : GPL-3
+Maintainer : andrew.lelechenko@gmail.com
+Stability : experimental
+
+-}
+
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE MagicHash #-}
+{-# LANGUAGE UnboxedTuples #-}
+
+{-# OPTIONS_GHC -fno-warn-type-defaults #-}
+{-# OPTIONS_GHC -O2 #-}
+{-# OPTIONS_GHC -optc-O3 #-}
+
+module Data.FastDigits.Internal
+ ( selectPower
+ , selectPower'
+ ) where
+
+import GHC.Exts
+
+#include "MachDeps.h"
+
+-- | Take an integer base and return (pow, base^pow),
+-- where base^pow <= maxBound and pow is as large as possible.
+selectPower :: Word# -> (# Word#, Word# #)
+#if WORD_SIZE_IN_BITS == 31
+selectPower 2## = (# 31##, 2147483648## #)
+#elif WORD_SIZE_IN_BITS == 32
+selectPower 2## = (# 31##, 2147483648## #)
+#else
+selectPower 2## = (# 63##, 9223372036854775808## #)
+#endif
+
+selectPower base = go base
+ where
+ go pw = case timesWord2# pw pw of
+ (# 0##, pw2 #)
+ -> let (# n, pw2n #) = go pw2 in
+ case timesWord2# pw pw2n of
+ (# 0##, pw2n1 #) -> (#n `timesWord#` 2## `plusWord#` 1##, pw2n1 #)
+ _ -> (# n `timesWord#` 2##, pw2n #)
+ _ -> (# 1##, pw #)
+
+-- | Take an integer base and return (pow, base^pow),
+-- where base^pow <= maxBound and pow is as large as possible.
+selectPower' :: Word -> (Word, Word)
+selectPower' (W# base) = (W# power, W# poweredBase)
+ where
+ (# power, poweredBase #) = selectPower base
diff --git a/src/Data/FastDigits.hs b/src/Data/FastDigits.hs
--- a/src/Data/FastDigits.hs
+++ b/src/Data/FastDigits.hs
@@ -1,16 +1,18 @@
{-|
Module : Data.FastDigits
-Description : The fast library for integer-to-digits conversion.
-Copyright : (c) Andrew Lelechenko, 2015-2016
+Description : Integer-to-digits conversion.
+Copyright : (c) Andrew Lelechenko, 2015-2020
License : GPL-3
Maintainer : andrew.lelechenko@gmail.com
Stability : experimental
Convert an integer to digits and back.
-Usually this library is twice as fast as "Data.Digits".
-For small bases and long numbers it may be up to 40 times faster.
+This library is both asymptotically (O(n^1.4) vs. O(n^2))
+and practically (2x-40x for typical inputs)
+faster than "Data.Digits".
-}
+{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE MagicHash #-}
{-# LANGUAGE UnboxedTuples #-}
@@ -82,15 +84,26 @@
else let (# fr, lr #) = digitsWordL base power r in
fr ++ replicate (I# (unsafeCoerce# lr)) 0 ++ f q
+padUpTo :: Int -> [Word] -> [Word]
+padUpTo !n [] = replicate n 0
+padUpTo !n (x : xs) = x : padUpTo (n - 1) xs
+
-- | Return digits of a non-negative number in reverse order.
digitsUnsigned
:: Word -- ^ Precondition that base is ≥2 is not checked
-> Natural
-> [Word]
digitsUnsigned (W# base) (NatS# n) = digitsWord base n
-digitsUnsigned (W# base) (NatJ# n) = case power of
- 1## -> digitsNatural base n
- _ -> digitsNatural' base power poweredBase n
+digitsUnsigned (W# base) (NatJ# n)
+ | halfSize <- sizeofBigNat# n `iShiftRL#` 1#
+ , isTrue# (halfSize ># 128#)
+ = let pow = I# (word2Int# power *# halfSize) in
+ let (nHi, nLo) = NatJ# n `quotRem` (NatS# poweredBase ^ (I# halfSize)) in
+ padUpTo pow (digitsUnsigned (W# base) nLo) ++ digitsUnsigned (W# base) nHi
+ | otherwise
+ = case power of
+ 1## -> digitsNatural base n
+ _ -> digitsNatural' base power poweredBase n
where
(# power, poweredBase #) = selectPower base
diff --git a/src/Data/FastDigits/Internal.hs b/src/Data/FastDigits/Internal.hs
deleted file mode 100644
--- a/src/Data/FastDigits/Internal.hs
+++ /dev/null
@@ -1,53 +0,0 @@
-{-|
-Module : Data.FastDigits.Internal
-Copyright : (c) Andrew Lelechenko, 2015-2016
-License : GPL-3
-Maintainer : andrew.lelechenko@gmail.com
-Stability : experimental
-
--}
-
-{-# LANGUAGE CPP #-}
-{-# LANGUAGE MagicHash #-}
-{-# LANGUAGE UnboxedTuples #-}
-
-{-# OPTIONS_GHC -fno-warn-type-defaults #-}
-{-# OPTIONS_GHC -O2 #-}
-{-# OPTIONS_GHC -optc-O3 #-}
-
-module Data.FastDigits.Internal
- ( selectPower
- , selectPower'
- ) where
-
-import GHC.Exts
-
-#include "MachDeps.h"
-
--- | Take an integer base and return (pow, base^pow),
--- where base^pow <= maxBound and pow is as large as possible.
-selectPower :: Word# -> (# Word#, Word# #)
-#if WORD_SIZE_IN_BITS == 31
-selectPower 2## = (# 31##, 2147483648## #)
-#elif WORD_SIZE_IN_BITS == 32
-selectPower 2## = (# 31##, 2147483648## #)
-#else
-selectPower 2## = (# 63##, 9223372036854775808## #)
-#endif
-
-selectPower base = go base
- where
- go pw = case timesWord2# pw pw of
- (# 0##, pw2 #)
- -> let (# n, pw2n #) = go pw2 in
- case timesWord2# pw pw2n of
- (# 0##, pw2n1 #) -> (#n `timesWord#` 2## `plusWord#` 1##, pw2n1 #)
- _ -> (# n `timesWord#` 2##, pw2n #)
- _ -> (# 1##, pw #)
-
--- | Take an integer base and return (pow, base^pow),
--- where base^pow <= maxBound and pow is as large as possible.
-selectPower' :: Word -> (Word, Word)
-selectPower' (W# base) = (W# power, W# poweredBase)
- where
- (# power, poweredBase #) = selectPower base