diff options
Diffstat (limited to 'Utility/FileSystemEncoding.hs')
| -rw-r--r-- | Utility/FileSystemEncoding.hs | 20 |
1 files changed, 18 insertions, 2 deletions
diff --git a/Utility/FileSystemEncoding.hs b/Utility/FileSystemEncoding.hs index 98f2f7755..ac105e73d 100644 --- a/Utility/FileSystemEncoding.hs +++ b/Utility/FileSystemEncoding.hs @@ -1,6 +1,6 @@ {- GHC File system encoding handling. - - - Copyright 2012 Joey Hess <joey@kitenet.net> + - Copyright 2012-2013 Joey Hess <joey@kitenet.net> - - Licensed under the GNU GPL version 3 or higher. -} @@ -10,7 +10,8 @@ module Utility.FileSystemEncoding ( withFilePath, md5FilePath, decodeW8, - encodeW8 + encodeW8, + truncateFilePath, ) where import qualified GHC.Foreign as GHC @@ -75,3 +76,18 @@ encodeW8 w8 = unsafePerformIO $ do - represent the FilePath on disk. -} decodeW8 :: FilePath -> [Word8] decodeW8 = s2w8 . _encodeFilePath + +{- Truncates a FilePath to the given number of bytes (or less), + - as represented on disk. + - + - Avoids returning an invalid part of a unicode byte sequence, at the + - cost of efficiency when running on a large FilePath. + -} +truncateFilePath :: Int -> FilePath -> FilePath +truncateFilePath n = go . reverse + where + go f = + let bytes = decodeW8 f + in if length bytes <= n + then reverse f + else go (drop 1 f) |