VDV 452 instances for serialisation

this may occasionally produce wrong output. In a lot of places I'm
not entirey sure if I understood the standard correctly …

1 files changed, 33 insertions, 4 deletions

diff --git a/vdv-server/VDV451.hs b/vdv-server/VDV451.hs
index 1d56e1c..b962208 100644
--- a/vdv-server/VDV451.hs
+++ b/vdv-server/VDV451.hs
@@ -47,10 +47,6 @@ instance ÖPNVEncode Text where
 instance ÖPNVEncode Day where
   encode day = "\""+|crop 2 d|+"."+|crop 2 m|+"."+|crop 4 y|+"\""
     where (y,m,d) = toGregorian day
-          crop n thing = if T.length shown < n
-            then T.replicate (n - T.length shown) "0" <> shown
-            else T.takeEnd n shown
-            where shown = T.pack $ show thing
 
 -- | for things which can be encoded as either string or number,
 -- this module defaults to strings. Add this newtype to the schema
@@ -69,6 +65,32 @@ instance ÖPNVEncode Int
 instance ÖPNVEncode Integer
 
 
+-- | these are encoded in a horrible format
+newtype Longitude = Longitude Double
+newtype Latitude = Latitude Double
+
+encodeGeoLength :: Double -> ByteString
+encodeGeoLength d' = ""+|sign|+""+|crop 3 deg|+""+|crop 2 min|+""+|crop 5 sec|+""
+  where deg = truncate d
+        min = truncate (d * 60) `mod` 60
+        sec = truncate (d * 3600 * 1000) `mod` (60 * 1000)
+        d = abs d'
+        sign :: Text
+        sign = if d' < 0 then "-" else ""
+
+instance ÖPNVEncode Latitude where
+  encode (Latitude d) = encodeGeoLength d
+instance ÖPNVEncode Longitude where
+  encode (Longitude d) = encodeGeoLength d
+
+-- | this isn't specified anywhere, but seems to be what VDV 452 implies
+instance ÖPNVEncode a => ÖPNVEncode (Maybe a) where
+  encode (Just a) = encode a
+  encode Nothing = "NULL"
+
+instance ÖPNVEncode Bool where
+  encode False = "0"
+  encode True = "1"
 
 data ÖPNVBefehl =
   MOD | SRC | CHS | VER | IFV
@@ -102,6 +124,7 @@ instance ÖPNVEncode ÖPNVType where
 
 class ÖPNVDatum a where
   tableName :: Proxy a -> ByteString
+  tableNumber :: Proxy a -> Int
   tableSchema :: Proxy a -> [(ByteString, ÖPNVType, a -> Feld)]
 
 encodeRow :: forall a. ÖPNVDatum a => a -> [Feld]
@@ -145,3 +168,9 @@ data ÖPNVOptions = ÖPNVOptions
       . C8.intercalate "; "
       . fmap (\case { (F a) -> encode a; Raw a -> a })
     (colNames, colTypes) = unzip (tableInfo (Proxy @a))
+
+
+crop n thing = if T.length shown < n
+  then T.replicate (n - T.length shown) "0" <> shown
+  else T.takeEnd n shown
+  where shown = T.pack $ show thing