implemented readMax

src/Network/Gemini/Capsule/Internal.hs

@@ -40,10 +40,15 @@ module Network.Gemini.Capsule.Internal (
   stripCRLF
 ) where
 
+import Control.Monad.Trans.Class (lift)
+import Control.Monad.Trans.Maybe (MaybeT (..))
 import qualified Data.ByteString as BS
-import Data.Connection (Connection)
+import Data.ByteString.Builder (Builder, byteString, toLazyByteString)
+import qualified Data.ByteString.Lazy as BSL
+import Data.Connection (Connection, source)
 import qualified Data.Text as T
 import Data.Text.Encoding (decodeUtf8')
+import System.IO.Streams as S
 
 import Network.Gemini.Capsule.Encoding
 import Network.Gemini.Capsule.Types
@@ -99,11 +104,24 @@ readMax
   -> Connection a
   -- ^ the 'Connection' to read from
   -> IO (Maybe BS.ByteString)
-readMax = undefined
+readMax maxLen conn = do
+  let src = source conn
+  runMaybeT $
+    BS.pack . BSL.unpack . toLazyByteString
+    <$> readLoop maxLen src
 
 -- | Strips the CR/LF characters from the end of a string, retuning
 -- Nothing if they are not present
 stripCRLF :: String -> Maybe String
 stripCRLF = undefined
 
+readLoop :: Int -> S.InputStream BS.ByteString -> MaybeT IO Builder
+readLoop maxLen src =
+  lift (S.read src) >>= \case
+    Nothing -> return mempty
+    Just bs -> let len = BS.length bs in
+      if len > maxLen
+        then MaybeT $ return Nothing
+        else (byteString bs <>) <$> readLoop (maxLen - len) src
+
 --jl