hprox-0.2.0: src/Util.hs

-- SPDX-License-Identifier: Apache-2.0
--
-- Copyright (C) 2023 Bin Jin. All Rights Reserved.
module Util (
    parseHostPort,
    parseHostPortWithDefault
) where

import qualified Data.ByteString       as BS
import qualified Data.ByteString.Char8 as BS8
import           Data.Maybe            (fromMaybe)

parseHostPort :: BS.ByteString -> Maybe (BS.ByteString, Int)
parseHostPort hostPort = do
    lastColon <- BS8.elemIndexEnd ':' hostPort
    port <- BS8.readInt (BS.drop (lastColon+1) hostPort) >>= checkPort
    return (BS.take lastColon hostPort, port)
  where
    checkPort (p, bs)
        | BS.null bs && 1 <= p && p <= 65535 = Just p
        | otherwise                          = Nothing

parseHostPortWithDefault :: Int -> BS.ByteString -> (BS.ByteString, Int)
parseHostPortWithDefault defaultPort hostPort =
    fromMaybe (hostPort, defaultPort) $ parseHostPort hostPort