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+-- | Module used for CSS compression. The compression is currently in a simple
+--   state, but would typically reduce the number of bytes by about 25%.
+module Text.Hakyll.Internal.CompressCSS
+    ( compressCSS
+    ) where
+
+import Data.List (isPrefixOf)
+
+import Text.Hakyll.Regex (substituteRegex)
+
+-- | Compress CSS to speed up your site.
+compressCSS :: String -> String
+compressCSS = compressSeparators
+            . stripComments
+            . compressWhitespace
+
+-- | Compresses certain forms of separators.
+compressSeparators :: String -> String
+compressSeparators = substituteRegex "; *}" "}" 
+                   . substituteRegex " *([{};:]) *" "\\1"
+                   . substituteRegex ";;*" ";"
+
+-- | Compresses all whitespace.
+compressWhitespace :: String -> String
+compressWhitespace = substituteRegex "[ \t\n][ \t\n]*" " "
+
+-- | Function that strips CSS comments away.
+stripComments :: String -> String
+stripComments [] = []
+stripComments str
+    | isPrefixOf "/*" str = stripComments $ eatComments $ drop 2 str
+    | otherwise = head str : stripComments (tail str)
+  where
+    eatComments str' | null str' = []
+                     | isPrefixOf "*/" str' = drop 2 str'
+                     | otherwise = eatComments $ tail str'