From 3465ba2f61872566e221235fba58001bbc2a3b67 Mon Sep 17 00:00:00 2001
From: John MacFarlane <fiddlosopher@gmail.com>
Date: Fri, 8 Feb 2013 09:45:15 -0800
Subject: [PATCH] UTF8: Strip off BOM if present.
Closes #743.
---
src/Text/Pandoc/UTF8.hs | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/src/Text/Pandoc/UTF8.hs b/src/Text/Pandoc/UTF8.hs
index 582afb6dc..a6921fc8f 100644
--- a/src/Text/Pandoc/UTF8.hs
+++ b/src/Text/Pandoc/UTF8.hs
@@ -86,10 +86,17 @@ hGetContents = fmap toStringLazy . BL.hGetContents
-- >> hSetNewlineMode h universalNewlineMode
-- >> IO.hGetContents h
+-- | Drop BOM (byte order marker) if present at beginning of string.
+-- Note that Data.Text converts the BOM to code point FEFF, zero-width
+-- no-break space, so if the string begins with this we strip it off.
+dropBOM :: String -> String
+dropBOM ('\xFEFF':xs) = xs
+dropBOM xs = xs
+
-- | Convert UTF8-encoded ByteString to String, also
-- removing '\r' characters.
toString :: B.ByteString -> String
-toString = filter (/='\r') . T.unpack . T.decodeUtf8
+toString = filter (/='\r') . dropBOM . T.unpack . T.decodeUtf8
fromString :: String -> B.ByteString
fromString = T.encodeUtf8 . T.pack
@@ -97,7 +104,7 @@ fromString = T.encodeUtf8 . T.pack
-- | Convert UTF8-encoded ByteString to String, also
-- removing '\r' characters.
toStringLazy :: BL.ByteString -> String
-toStringLazy = filter (/='\r') . TL.unpack . TL.decodeUtf8
+toStringLazy = filter (/='\r') . dropBOM . TL.unpack . TL.decodeUtf8
fromStringLazy :: String -> BL.ByteString
fromStringLazy = TL.encodeUtf8 . TL.pack