WIP: cleaner PgQuery functions

src/RangeQuery.hs

@@ -1,8 +1,16 @@
-module RangeQuery where
+module RangeQuery (
+  rangeParse
+, rangeRequested
+, rangeLimit
+, rangeOffset
+, NonnegRange
+) where
 
 import Control.Applicative
 import Network.HTTP.Types.Header
 
+import qualified Data.ByteString.Char8 as BS
+
 import Data.Ranged.Boundaries
 import Data.Ranged.Ranges
 
@@ -14,6 +22,33 @@ import Data.Maybe (fromMaybe, listToMaybe)
 
 type NonnegRange = Range Int
 
+rangeParse :: BS.ByteString -> Maybe NonnegRange
+rangeParse range = do
+  let rangeRegex = "^([0-9]+)-([0-9]*)$" :: BS.ByteString
+
+  parsedRange <- listToMaybe (range =~ rangeRegex :: [[BS.ByteString]])
+
+  let [_, from, to] = readMaybe . cs <$> parsedRange
+  let lower = fromMaybe emptyRange   (rangeGeq <$> from)
+  let upper = fromMaybe (rangeGeq 0) (rangeLeq <$> to)
+
+  return $ rangeIntersection lower upper
+
+rangeRequested :: RequestHeaders -> Maybe NonnegRange
+rangeRequested = (rangeParse =<<) . lookup hRange
+
+rangeLimit :: NonnegRange -> Maybe Int
+rangeLimit range =
+  case [rangeLower range, rangeUpper range]
+    of [BoundaryBelow from, BoundaryAbove to] -> Just (1 + to - from)
+       _ -> Nothing
+
+rangeOffset :: NonnegRange -> Int
+rangeOffset range =
+  case rangeLower range
+    of BoundaryBelow from -> from
+       _ -> error "range without lower bound" -- should never happen
+
 rangeGeq :: Int -> NonnegRange
 rangeGeq n =
   Range (BoundaryBelow n) BoundaryAboveAll
@@ -21,33 +56,3 @@ rangeGeq n =
 rangeLeq :: Int -> NonnegRange
 rangeLeq n =
   Range BoundaryBelowAll (BoundaryAbove n)
-
-parseRange :: String -> Maybe NonnegRange
-parseRange range = do
-  let rangeRegex = "^([0-9]+)-([0-9]*)$" :: String
-
-  parsedRange <- listToMaybe (range =~ rangeRegex :: [[String]])
-
-  let [_, from, to] = readMaybe <$> parsedRange
-  let lower = fromMaybe emptyRange   (rangeGeq <$> from)
-  let upper = fromMaybe (rangeGeq 0) (rangeLeq <$> to)
-
-  return $ rangeIntersection lower upper
-
-requestedRange :: RequestHeaders -> Maybe NonnegRange
-requestedRange hdrs = parseRange =<< cs <$> lookup hRange hdrs
-
-requestedContentRange :: RequestHeaders -> Maybe NonnegRange
-requestedContentRange hdrs = parseRange =<< cs <$> lookup "Content-Range" hdrs
-
-limit :: NonnegRange -> Maybe Int
-limit range =
-  case [rangeLower range, rangeUpper range]
-    of [BoundaryBelow from, BoundaryAbove to] -> Just (1 + to - from)
-       _ -> Nothing
-
-offset :: NonnegRange -> Int
-offset range =
-  case rangeLower range
-    of BoundaryBelow from -> from
-       _ -> error "range without lower bound" -- should never happen