17 lines
503 B
Haskell
17 lines
503 B
Haskell
|
module Data.ByteString.Char8.Util (
|
||
|
|
previous
|
||
|
|
, subBS
|
||
|
|
) where
|
||
|
|
|
||
|
|
import Data.ByteString.Char8 (ByteString)
|
||
|
|
import qualified Data.ByteString.Char8 as BS (drop, index, take)
|
||
|
|
import Prelude hiding (length)
|
||
|
|
|
||
|
|
previous :: Char -> Int -> ByteString -> Int
|
||
|
|
previous char position byteString
|
||
|
|
| BS.index byteString position == char = position
|
||
|
|
| otherwise = previous char (position - 1) byteString
|
||
|
|
|
||
|
|
subBS :: Int -> Int -> ByteString -> ByteString
|
||
|
|
subBS offset length = BS.take length . BS.drop offset
|