fe46b27 · text · git.iko.soy

git.iko.soy/text

Refactor text equality check

--HG-- extra : convert_revision : 6c8fa24f7caa5feba542fdd2ea529e9e0d10927b

commitfe46b27df0ef4bf728a4711bedfb601ea889bf91 authorBryan O'Sullivan <bos@serpentine.com> dateTue 19 Oct 2010, 05:24 (16 years ago) parentf5c1691

2 files changed+32−13

compare with master

unifiedsplit

Data/Text.hs+3−13 Data/Text/Array.hs+29

Data/Text.hs+3−13

@@ -254,20 +254,10 @@ import Data.Int (Int64)

254254-- Functions that can be fused by the compiler are marked with the

255255-- phrase \"Subject to fusion\".

256256

257−eq :: Text -> Text -> Bool

258−eq (Text arrA offA lenA) (Text arrB offB lenB)

259− | lenA /= lenB = False

260− | otherwise = go 0

261− where

262− go !n | n == lenA = True

263− | a /= b = False

264− | otherwise = go (n+1)

265− where a = A.unsafeIndex arrA (offA+n)

266− b = A.unsafeIndex arrB (offB+n)

267−{-# INLINE eq #-}

268−

269257instance Eq Text where

270− (==) = eq

258+ Text arrA offA lenA == Text arrB offB lenB

259+ | lenA == lenB = A.equal arrA offA arrB offB lenA

260+ | otherwise = False

271261 {-# INLINE (==) #-}

272262

273263instance Ord Text where

Data/Text/Array.hs+29

@@ -33,6 +33,7 @@ module Data.Text.Array

3333 , copyM

3434 , copyI

3535 , empty

36+ , equal

3637#if defined(ASSERTS)

3738 , length

3839#endif

@@ -265,3 +266,31 @@ copyI dest i0 src j0 top

265266 | i >= top = return ()

266267 | otherwise = do unsafeWrite dest i (src `unsafeIndex` j)

267268 slow (i+1) (j+1)

269+

270+-- | Compare portions of two arrays for equality. No bounds checking

271+-- is performed.

272+equal :: Array -- ^ First

273+ -> Int -- ^ Offset into first

274+ -> Array -- ^ Second

275+ -> Int -- ^ Offset into second

276+ -> Int -- ^ Count

277+ -> Bool

278+equal arrA offA arrB offB count

279+ | wordAligned offA && wordAligned offB = fast 0

280+ | otherwise = slow 0

281+ where

282+ countWords = count `div` wordFactor

283+ fast !i

284+ | i >= countWords = slow (i * wordFactor)

285+ | a /= b = False

286+ | otherwise = fast (i+1)

287+ where a = unsafeIndexWord arrA (offAW+i)

288+ b = unsafeIndexWord arrB (offBW+i)

289+ offAW = offA `div` wordFactor

290+ offBW = offB `div` wordFactor

291+ slow !i

292+ | i >= count = True

293+ | a /= b = False

294+ | otherwise = slow (i+1)

295+ where a = unsafeIndex arrA (offA+i)

296+ b = unsafeIndex arrB (offB+i)