fix copyright notice

[functorrent.git] / src / FuncTorrent / Utils.hs

diff --git a/src/FuncTorrent/Utils.hs b/src/FuncTorrent/Utils.hs
index 48ebe67710d81258b9600c874dec3de414d52cf5..4d89e8348cdf2d8a3f71caf47935b285083ca9fc 100644 (file)
--- a/src/FuncTorrent/Utils.hs
+++ b/src/FuncTorrent/Utils.hs
@@ -1,3 +1,22 @@
+{-
+ - Copyright (C) 2015-2016 Ramakrishnan Muthukrishnan <ram@rkrishnan.org>
+ -
+ - This file is part of FuncTorrent.
+ -
+ - FuncTorrent is free software; you can redistribute it and/or modify
+ - it under the terms of the GNU General Public License as published by
+ - the Free Software Foundation; either version 3 of the License, or
+ - (at your option) any later version.
+ -
+ - FuncTorrent is distributed in the hope that it will be useful,
+ - but WITHOUT ANY WARRANTY; without even the implied warranty of
+ - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ - GNU General Public License for more details.
+ -
+ - You should have received a copy of the GNU General Public License
+ - along with FuncTorrent; if not,  see <http://www.gnu.org/licenses/>
+ -}
+
 module FuncTorrent.Utils
        (createDummyFile,
         writeFileAtOffset,
@@ -11,9 +30,10 @@ module FuncTorrent.Utils
 import Prelude hiding (writeFile, take)
 
 import qualified Crypto.Hash.SHA1 as SHA1 (hash)
+import Control.Exception.Base (IOException, try)
 import Data.ByteString (ByteString, writeFile, hPut, hGet, take)
 import qualified Data.ByteString.Char8 as BC
-import System.IO (withFile, hSeek, IOMode(..), SeekMode(..))
+import System.IO (Handle, hSeek, SeekMode(..))
 import System.Directory (doesFileExist)
 
 splitN :: Int -> BC.ByteString -> [BC.ByteString]
@@ -25,25 +45,25 @@ splitNum n d | n == 0 = []
              | n < d = [n]
              | otherwise = d : splitNum (n - d) d
 
-createDummyFile :: FilePath -> Int -> IO ()
+createDummyFile :: FilePath -> Int -> IO (Either IOException ())
 createDummyFile path size = do
   dfe <- doesFileExist path
-  if dfe
-    then return ()
+  if not dfe
+    then do
+    try $ writeFile path (BC.replicate size '\0')
     else
-    writeFile path (BC.replicate size '\0')
+    return $ Right ()
 
 -- write into a file at a specific offet
-writeFileAtOffset :: FilePath -> Integer -> ByteString -> IO ()
-writeFileAtOffset path offset block =
-  withFile path ReadWriteMode (\h -> do
-                                  hSeek h AbsoluteSeek offset
-                                  hPut h block)
-readFileAtOffset :: FilePath -> Integer -> Integer -> IO ByteString
-readFileAtOffset path offset len =
-  withFile path ReadWriteMode (\h -> do
-                                  hSeek h AbsoluteSeek offset
-                                  hGet h (fromInteger len))
+writeFileAtOffset :: Handle -> Integer -> ByteString -> IO ()
+writeFileAtOffset h offset block = do
+  hSeek h AbsoluteSeek offset
+  hPut h block
+
+readFileAtOffset :: Handle -> Integer -> Integer -> IO ByteString
+readFileAtOffset h offset len = do
+  hSeek h AbsoluteSeek offset
+  hGet h (fromInteger len)
 
 verifyHash :: ByteString -> ByteString -> Bool
 verifyHash bs pieceHash =