115 lines
3.3 KiB
Haskell
115 lines
3.3 KiB
Haskell
{-# LANGUAGE CPP #-}
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{-
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UTF-8 aware string IO functions that will work across multiple platforms
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and GHC versions. Includes code from Text.Pandoc.UTF8 ((C) 2010 John
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MacFarlane <jgm@berkeley.edu>).
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Example usage:
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import Prelude hiding (readFile,writeFile,appendFile,getContents,putStr,putStrLn)
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import UTF8IOCompat (readFile,writeFile,appendFile,getContents,putStr,putStrLn)
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import UTF8IOCompat (SystemString,fromSystemString,toSystemString,error',userError')
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-}
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module Hledger.Utils.UTF8IOCompat (
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readFile,
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writeFile,
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appendFile,
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getContents,
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hGetContents,
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putStr,
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putStrLn,
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hPutStr,
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hPutStrLn,
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--
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SystemString,
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fromSystemString,
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toSystemString,
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error',
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userError',
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)
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where
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import qualified Data.ByteString.Lazy as B
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import Data.ByteString.Lazy.UTF8 (toString, fromString)
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import Prelude hiding (readFile, writeFile, appendFile, getContents, putStr, putStrLn)
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import System.IO (Handle)
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import Control.Monad (liftM)
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#if __GLASGOW_HASKELL__ < 702
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import Codec.Binary.UTF8.String as UTF8 (decodeString, encodeString, isUTF8Encoded)
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import System.Info (os)
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#endif
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bom :: B.ByteString
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bom = B.pack [0xEF, 0xBB, 0xBF]
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stripBOM :: B.ByteString -> B.ByteString
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stripBOM s | bom `B.isPrefixOf` s = B.drop 3 s
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stripBOM s = s
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readFile :: FilePath -> IO String
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readFile = liftM (toString . stripBOM) . B.readFile
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writeFile :: FilePath -> String -> IO ()
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writeFile f = B.writeFile f . fromString
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appendFile :: FilePath -> String -> IO ()
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appendFile f = B.appendFile f . fromString
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getContents :: IO String
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getContents = liftM (toString . stripBOM) B.getContents
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hGetContents :: Handle -> IO String
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hGetContents h = liftM (toString . stripBOM) (B.hGetContents h)
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putStr :: String -> IO ()
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putStr = B.putStr . fromString
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putStrLn :: String -> IO ()
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putStrLn = B.putStrLn . fromString
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hPutStr :: Handle -> String -> IO ()
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hPutStr h = B.hPutStr h . fromString
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hPutStrLn :: Handle -> String -> IO ()
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hPutStrLn h s = hPutStr h (s ++ "\n")
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-- | A string received from or being passed to the operating system, such
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-- as a file path, command-line argument, or environment variable name or
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-- value. With GHC versions before 7.2 on some platforms (posix) these are
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-- typically encoded. When converting, we assume the encoding is UTF-8 (cf
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-- http://www.dwheeler.com/essays/fixing-unix-linux-filenames.html#UTF8).
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type SystemString = String
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-- | Convert a system string to an ordinary string, decoding from UTF-8 if
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-- it appears to be UTF8-encoded and GHC version is less than 7.2.
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fromSystemString :: SystemString -> String
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#if __GLASGOW_HASKELL__ < 702
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fromSystemString s = if UTF8.isUTF8Encoded s then UTF8.decodeString s else s
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#else
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fromSystemString = id
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#endif
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-- | Convert a unicode string to a system string, encoding with UTF-8 if
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-- we are on a posix platform with GHC < 7.2.
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toSystemString :: String -> SystemString
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#if __GLASGOW_HASKELL__ < 702
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toSystemString = case os of
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"unix" -> UTF8.encodeString
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"linux" -> UTF8.encodeString
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"darwin" -> UTF8.encodeString
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_ -> id
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#else
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toSystemString = id
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#endif
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-- | A SystemString-aware version of error.
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error' :: String -> a
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error' = error . toSystemString
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-- | A SystemString-aware version of userError.
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userError' :: String -> IOError
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userError' = userError . toSystemString
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