Data.Time.RFC822 now fully works

[time-http.git] / Data / Time / HTTP / Common.hs

diff --git a/Data/Time/HTTP/Common.hs b/Data/Time/HTTP/Common.hs
new file mode 100644 (file)
index 0000000..1ea61de
--- /dev/null
+++ b/Data/Time/HTTP/Common.hs
@@ -0,0 +1,151 @@
+{-# LANGUAGE FlexibleContexts #-}
+module Data.Time.HTTP.Common
+    ( shortWeekDayName
+    , shortWeekDayNameP
+
+    , longWeekDayName
+    , longWeekDayNameP
+
+    , shortMonthName
+    , shortMonthNameP
+
+    , show2
+    , show4
+
+    , read2
+    , read4
+    )
+    where
+
+import Control.Monad
+import Text.Parsec
+
+shortWeekDayName :: Int -> String
+shortWeekDayName 1 = "Mon"
+shortWeekDayName 2 = "Tue"
+shortWeekDayName 3 = "Wed"
+shortWeekDayName 4 = "Thu"
+shortWeekDayName 5 = "Fri"
+shortWeekDayName 6 = "Sat"
+shortWeekDayName 7 = "Sun"
+shortWeekDayName n = error ("shortWeekDayName: unknown day number: " ++ show n)
+
+shortWeekDayNameP :: Stream s m Char => ParsecT s u m Int
+shortWeekDayNameP
+    = choice [ string "Mon" >> return 1
+             , char 'T'
+               >> choice [ string "ue" >> return 2
+                         , string "hu" >> return 4
+                         ]
+             , string "Wed" >> return 3
+             , string "Fri" >> return 5
+             , char 'S'
+               >> choice [ string "at" >> return 6
+                         , string "un" >> return 7
+                         ]
+             ]
+
+longWeekDayName :: Int -> String
+longWeekDayName 1 = "Monday"
+longWeekDayName 2 = "Tuesday"
+longWeekDayName 3 = "Wednesday"
+longWeekDayName 4 = "Thursday"
+longWeekDayName 5 = "Friday"
+longWeekDayName 6 = "Saturday"
+longWeekDayName 7 = "Sunday"
+
+longWeekDayNameP :: Stream s m Char => ParsecT s u m Int
+longWeekDayNameP
+    = choice [ string "Monday" >> return 1
+             , char 'T'
+               >> choice [ string "uesday"  >> return 2
+                         , string "hursday" >> return 4
+                         ]
+             , string "Wednesday" >> return 3
+             , string "Friday"    >> return 5
+             , char 'S'
+               >> choice [ string "aturday" >> return 6
+                         , string "unday"   >> return 7
+                         ]
+             ]
+
+shortMonthName :: Int -> String
+shortMonthName  1 = "Jan"
+shortMonthName  2 = "Feb"
+shortMonthName  3 = "Mar"
+shortMonthName  4 = "Apr"
+shortMonthName  5 = "May"
+shortMonthName  6 = "Jun"
+shortMonthName  7 = "Jul"
+shortMonthName  8 = "Aug"
+shortMonthName  9 = "Sep"
+shortMonthName 10 = "Oct"
+shortMonthName 11 = "Nov"
+shortMonthName 12 = "Dec"
+shortMonthName  n = error ("shortMonthName: unknown month number: " ++ show n)
+
+shortMonthNameP :: Stream s m Char => ParsecT s u m Int
+shortMonthNameP
+    = choice [ char 'J'
+               >> choice [ string "an" >> return 1
+                         , char 'u'
+                           >> choice [ char 'n' >> return 6
+                                     , char 'l' >> return 7
+                                     ]
+                         ]
+             , string "Feb" >> return 2
+             , string "Ma"
+               >> choice [ char 'r' >> return 3
+                         , char 'y' >> return 5
+                         ]
+             , char 'A'
+               >> choice [ string "pr" >> return 4
+                         , string "ug" >> return 8
+                         ]
+             , string "Sep" >> return 9
+             , string "Oct" >> return 10
+             , string "Nov" >> return 11
+             , string "Dec" >> return 12
+             ]
+
+show4 :: Integral i => i -> String
+show4 i
+    | i >= 0 && i < 10    = "000" ++ show i
+    | i >= 0 && i < 100   = "00"  ++ show i
+    | i >= 0 && i < 1000  = "0"   ++ show i
+    | i >= 0 && i < 10000 = show i
+    | otherwise          = error ("show4: the integer i must satisfy 0 <= i < 10000: " ++ show i)
+
+show2 :: Integral i => i -> String
+show2 i
+    | i >= 0 && i < 10  = "0" ++ show i
+    | i >= 0 && i < 100 = show i
+    | otherwise         = error ("show2: the integer i must satisfy 0 <= i < 100: " ++ show i)
+
+read4 :: (Stream s m Char, Num n) => ParsecT s u m n
+read4 = do n1 <- digit'
+           n2 <- digit'
+           n3 <- digit'
+           n4 <- digit'
+           return (n1 * 1000 + n2 * 100 + n3 * 10 + n4)
+
+read2 :: (Stream s m Char, Num n) => ParsecT s u m n
+read2 = do n1 <- digit'
+           n2 <- digit'
+           return (n1 * 10 + n2)
+
+digit' :: (Stream s m Char, Num n) => ParsecT s u m n
+digit' = liftM fromC digit
+
+fromC :: Num n => Char -> n
+fromC '0' = 0
+fromC '1' = 1
+fromC '2' = 2
+fromC '3' = 3
+fromC '4' = 4
+fromC '5' = 5
+fromC '6' = 6
+fromC '7' = 7
+fromC '8' = 8
+fromC '9' = 9
+fromC _   = undefined