4e82935 · text · git.iko.soy

git.iko.soy/text

A small improvement in Text generation efficiency.

The specialised Run tuple avoids boxing and indirection for both the MArray and Int parameters in the predecessor code. I think I can do better, though.

commit4e829356c48b0e5247d64d4a119b0e32b2bd9fc1 authorBryan O'Sullivan <bos@serpentine.com> dateSun 17 Jun 2012, 11:38 (14 years ago) parent0d6d979

2 files changed+18−5

compare with master

unifiedsplit

Data/Text/Fusion.hs+4−3 Data/Text/Private.hs+14−2

Data/Text/Fusion.hs+4−3

@@ -51,6 +51,7 @@ import Prelude (Bool(..), Char, Maybe(..), Monad(..), Int,

5151 fromIntegral, otherwise)

5252import Data.Bits ((.&.))

5353import Data.Text.Internal (Text(..))

54+import Data.Text.Private (Run(..), runText)

5455import Data.Text.UnsafeChar (ord, unsafeChr, unsafeWrite)

5556import Data.Text.UnsafeShift (shiftL, shiftR)

5657import qualified Data.Text.Array as A

@@ -94,15 +95,15 @@ reverseStream (Text arr off len) = Stream next (off+len-1) (maxSize len)

9495

9596-- | /O(n)/ Convert a 'Stream Char' into a 'Text'.

9697unstream :: Stream Char -> Text

97−unstream (Stream next0 s0 len) = I.textP (P.fst a) 0 (P.snd a)

98+unstream (Stream next0 s0 len) = a

9899 where

99− a = A.run2 (A.new mlen >>= \arr -> outer arr mlen s0 0)

100+ a = runText (A.new mlen >>= \arr -> outer arr mlen s0 0)

100101 where mlen = upperBound 4 len

101102 outer arr top = loop

102103 where

103104 loop !s !i =

104105 case next0 s of

105− Done -> return (arr, i)

106+ Done -> return (Run arr i)

106107 Skip s' -> loop s' i

107108 Yield x s'

108109 | j >= top -> {-# SCC "unstream/resize" #-} do

Data/Text/Private.hs+14−2

@@ -1,4 +1,4 @@

1−{-# LANGUAGE BangPatterns, UnboxedTuples #-}

1+{-# LANGUAGE BangPatterns, Rank2Types, UnboxedTuples #-}

33-- |

44-- Module : Data.Text.Private

@@ -11,11 +11,15 @@

1111

1212module Data.Text.Private

1313 (

14− span_

14+ Run(..)

15+ , runText

16+ , span_

1517 ) where

1618

19+import Control.Monad.ST (ST, runST)

1720import Data.Text.Internal (Text(..), textP)

1821import Data.Text.Unsafe (Iter(..), iter)

22+import qualified Data.Text.Array as A

1923

2024span_ :: (Char -> Bool) -> Text -> (# Text, Text #)

2125span_ p t@(Text arr off len) = (# hd,tl #)

@@ -26,3 +30,11 @@ span_ p t@(Text arr off len) = (# hd,tl #)

2630 | otherwise = i

2731 where Iter c d = iter t i

2832{-# INLINE span_ #-}

33+

34+data Run s = Run !(A.MArray s) !Int

35+

36+runText :: (forall s. ST s (Run s)) -> Text

37+runText act = runST (do Run marr len <- act

38+ arr <- A.unsafeFreeze marr

39+ return (textP arr 0 len))

40+{-# INLINE runText #-}