-- | Compare a string with a copy of itself that is identical except -- for the last character. -- -- Tested in this benchmark: -- -- * Comparison of strings (Eq instance) -- module Benchmarks.Equality ( benchmark ) where import Criterion (Benchmark, bgroup, bench, whnf) import qualified Data.ByteString.Char8 as B import qualified Data.ByteString.Lazy.Char8 as BL import qualified Data.Text as T import qualified Data.Text.Encoding as T import qualified Data.Text.Lazy as TL import qualified Data.Text.Lazy.Encoding as TL benchmark :: FilePath -> IO Benchmark benchmark fp = do b <- B.readFile fp bl1 <- BL.readFile fp -- A lazy bytestring is a list of chunks. When we do not explicitly create two -- different lazy bytestrings at a different address, the bytestring library -- will compare the chunk addresses instead of the chunk contents. This is why -- we read the lazy bytestring twice here. bl2 <- BL.readFile fp l <- readFile fp let t = T.decodeUtf8 b tl = TL.decodeUtf8 bl1 return $ bgroup "Equality" [ bench "Text" $ whnf (== T.init t `T.snoc` '\xfffd') t , bench "LazyText" $ whnf (== TL.init tl `TL.snoc` '\xfffd') tl , bench "ByteString" $ whnf (== B.init b `B.snoc` '\xfffd') b , bench "LazyByteString" $ whnf (== BL.init bl2 `BL.snoc` '\xfffd') bl1 , bench "String" $ whnf (== init l ++ "\xfffd") l ]