diff options
Diffstat (limited to 'compiler/utils/FastString.hs')
| -rw-r--r-- | compiler/utils/FastString.hs | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/compiler/utils/FastString.hs b/compiler/utils/FastString.hs index 8f76584875..8d1bbb5c67 100644 --- a/compiler/utils/FastString.hs +++ b/compiler/utils/FastString.hs @@ -23,6 +23,10 @@ -- * Outputing them is fast. -- * Generated by 'sLit'. -- * Turn into 'Outputable.SDoc' with 'Outputable.ptext' +-- * Requires manual memory management. +-- Improper use may lead to memory leaks or dangling pointers. +-- * It assumes Latin-1 as the encoding, therefore it cannot represent +-- arbitrary Unicode strings. -- -- Use 'LitString' unless you want the facilities of 'FastString'. module FastString @@ -560,14 +564,19 @@ hPutFS handle fs = BS.hPut handle $ fastStringToByteString fs -- ----------------------------------------------------------------------------- -- LitStrings, here for convenience only. +-- | A 'LitString' is a pointer to some null-terminated array of bytes. type LitString = Ptr Word8 --Why do we recalculate length every time it's requested? --If it's commonly needed, we should perhaps have --data LitString = LitString {-#UNPACK#-}!Addr# {-#UNPACK#-}!Int# +-- | Wrap an unboxed address into a 'LitString'. mkLitString# :: Addr# -> LitString mkLitString# a# = Ptr a# +-- | Encode a 'String' into a newly allocated 'LitString' using Latin-1 +-- encoding. The original string must not contain non-Latin-1 characters +-- (above codepoint @0xff@). {-# INLINE mkLitString #-} mkLitString :: String -> LitString mkLitString s = @@ -583,9 +592,13 @@ mkLitString s = return p ) +-- | Decode a 'LitString' back into a 'String' using Latin-1 encoding. +-- This does not free the memory associated with 'LitString'. unpackLitString :: LitString -> String unpackLitString (Ptr p) = unpackCString# p +-- | Compute the length of a 'LitString', which must necessarily be +-- null-terminated. lengthLS :: LitString -> Int lengthLS = ptrStrLength |