Foreign.C.UTF8

Marshall Haskell Strings to and from UTF8-encoded CStrings. This module's code is inspired by John Meacham's UTF8 en- & de-coders, and also those found in the HXT library (module Text.XML.HXT.DOM.Unicode).

Note that the -Len functions all return the length in bytes, not Chars (this is more useful, as you are most likely to want to pass the length to an FFI function, which is most likely expecting the length in bytes). If you want the length in Chars, well, you have the original String, so...

Documentation

peekUTF8String :: CString -> IO String

Analogous to peekCString. Converts UTF8 CString to String.

peekUTF8StringLen :: CStringLen -> IO String

Analogous to peekCStringLen. Converts UTF8 CString to String. The resulting String will end either when len bytes have been converted, or when a NULL is found.

newUTF8String :: String -> IO CString

Analogous to newCString. Creates UTF8 encoded CString.

withUTF8String :: String -> (CString -> IO a) -> IO a

Analogous to withCString. Creates UTF8 encoded CString.

withUTF8StringLen :: String -> (CStringLen -> IO a) -> IO a

Analogous to withCStringLen. The length returned is in bytes (encoding units), not chars.

toUTF8String :: String -> String

Convert a Haskell String into a UTF8 String, where each UTF8 byte is represented by its Char equivalent i.e. only chars 0-255 are used. The resulting String can be marshalled to CString directly i.e. with a Latin-1 encoding.

fromUTF8String :: String -> String

Convert a String that was marshalled from a CString without any decoder applied. This might be useful if the client encoding is unknown, and the user code must convert. We assume that the UTF8 CString was marshalled as if Latin-1 i.e. all chars are in the range 0-255.

lengthUTF8 :: String -> Int

fromUTF8 :: [Word8] -> String

Convert UTF-8 to Unicode.

toUTF8 :: String -> [Word8]

Convert Unicode characters to UTF-8.