b696eb0 · text · git.iko.soy

on master help sign in

Extract the loop from dropEnd

b696eb0Bryan O'Sullivan13 years ago

Data/Text.hs+9−6

@@ -1018,6 +1018,14 @@ take n t@(Text arr off len)

1018 unstream (S.take n (stream t)) = take n t

1019 #-}

1020

1021+iterNEnd :: Int -> Text -> Int

1022+iterNEnd n t@(Text _arr _off len) = loop (len-1) n

1023+ where loop i !m

1024+ | i <= 0 = 0

1025+ | m <= 1 = i

1026+ | otherwise = loop (i+d) (m-1)

1027+ where d = reverseIter_ t i

1028+

1021-- | /O(n)/ 'drop' @n@, applied to a 'Text', returns the suffix of the

1029-- | /O(n)/ 'drop' @n@, applied to a 'Text', returns the suffix of the

1022-- 'Text' after the first @n@ characters, or the empty 'Text' if @n@

1030-- 'Text' after the first @n@ characters, or the empty 'Text' if @n@

1023-- is greater than the length of the 'Text'. Subject to fusion.

1031-- is greater than the length of the 'Text'. Subject to fusion.

@@ -1049,12 +1057,7 @@ dropEnd :: Int -> Text -> Text

1049dropEnd n t@(Text arr off len)

1057dropEnd n t@(Text arr off len)

1050 | n <= 0 = t

1058 | n <= 0 = t

1051 | n >= len = empty

1059 | n >= len = empty

1052− | otherwise = loop (len-1) n

1060+ | otherwise = text arr off (iterNEnd n t)

1053− where loop i !m

1054− | i <= 0 = empty

1055− | m <= 1 = Text arr off i

1056− | otherwise = loop (i+d) (m-1)

1057− where d = reverseIter_ t i

1058

1061

1059-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text',

1062-- | /O(n)/ 'takeWhile', applied to a predicate @p@ and a 'Text',

1060-- returns the longest prefix (possibly empty) of elements that

1063-- returns the longest prefix (possibly empty) of elements that