From 7bc879268c1a86799a642280c296011e07e98c77 Mon Sep 17 00:00:00 2001 From: John MacFarlane Date: Fri, 10 Aug 2018 15:13:19 -0700 Subject: Avoid non-exhaustive pattern match. --- src/Text/Pandoc/ImageSize.hs | 22 ++++++++++++---------- 1 file changed, 12 insertions(+), 10 deletions(-) (limited to 'src/Text/Pandoc') diff --git a/src/Text/Pandoc/ImageSize.hs b/src/Text/Pandoc/ImageSize.hs index c5fe98a66..00ab86eab 100644 --- a/src/Text/Pandoc/ImageSize.hs +++ b/src/Text/Pandoc/ImageSize.hs @@ -319,20 +319,22 @@ pngSize img = do (shift w1 24 + shift w2 16 + shift w3 8 + w4, shift h1 24 + shift h2 16 + shift h3 8 + h4) _ -> Nothing -- "PNG parse error" - let (dpix, dpiy) = findpHYs rest'' + (dpix, dpiy) <- findpHYs rest'' return ImageSize { pxX = x, pxY = y, dpiX = dpix, dpiY = dpiy } -findpHYs :: ByteString -> (Integer, Integer) +findpHYs :: ByteString -> Maybe (Integer, Integer) findpHYs x - | B.null x || "IDAT" `B.isPrefixOf` x = (72,72) + | B.null x || "IDAT" `B.isPrefixOf` x = return (72,72) | "pHYs" `B.isPrefixOf` x = - let [x1,x2,x3,x4,y1,y2,y3,y4,u] = - map fromIntegral $ unpack $ B.take 9 $ B.drop 4 x - factor = if u == 1 -- dots per meter - then \z -> z * 254 `div` 10000 - else const 72 - in ( factor $ shift x1 24 + shift x2 16 + shift x3 8 + x4, - factor $ shift y1 24 + shift y2 16 + shift y3 8 + y4 ) + case map fromIntegral $ unpack $ B.take 9 $ B.drop 4 x of + [x1,x2,x3,x4,y1,y2,y3,y4,u] -> do + let factor = if u == 1 -- dots per meter + then \z -> z * 254 `div` 10000 + else const 72 + return + ( factor $ shift x1 24 + shift x2 16 + shift x3 8 + x4, + factor $ shift y1 24 + shift y2 16 + shift y3 8 + y4 ) + _ -> mzero | otherwise = findpHYs $ B.drop 1 x -- read another byte gifSize :: ByteString -> Maybe ImageSize -- cgit v1.2.3