diff options
Diffstat (limited to 'compiler/utils/FastString.lhs')
| -rw-r--r-- | compiler/utils/FastString.lhs | 75 |
1 files changed, 71 insertions, 4 deletions
diff --git a/compiler/utils/FastString.lhs b/compiler/utils/FastString.lhs index 2c94de75f9..05a379808e 100644 --- a/compiler/utils/FastString.lhs +++ b/compiler/utils/FastString.lhs @@ -26,6 +26,16 @@ -- Use 'LitString' unless you want the facilities of 'FastString'. module FastString ( + -- * FastBytes + FastBytes(..), + mkFastStringFastBytes, + foreignPtrToFastBytes, + fastStringToFastBytes, + bytesFB, + hashFB, + lengthFB, + appendFB, + -- * FastStrings FastString(..), -- not abstract, for now. @@ -117,6 +127,61 @@ import GHC.Base ( unpackCString# ) #define hASH_TBL_SIZE_UNBOXED 4091# +data FastBytes = FastBytes { + fb_n_bytes :: {-# UNPACK #-} !Int, -- number of bytes + fb_buf :: {-# UNPACK #-} !(ForeignPtr Word8) + } deriving Typeable + +instance Data FastBytes where + -- don't traverse? + toConstr _ = abstractConstr "FastBytes" + gunfold _ _ = error "gunfold" + dataTypeOf _ = mkNoRepType "FastBytes" + +instance Eq FastBytes where + x == y = (x `compare` y) == EQ + +instance Ord FastBytes where + compare = cmpFB + +foreignPtrToFastBytes :: ForeignPtr Word8 -> Int -> FastBytes +foreignPtrToFastBytes fp len = FastBytes len fp + +mkFastStringFastBytes :: FastBytes -> IO FastString +mkFastStringFastBytes (FastBytes len fp) + = withForeignPtr fp $ \ptr -> mkFastStringForeignPtr ptr fp len + +fastStringToFastBytes :: FastString -> FastBytes +fastStringToFastBytes f = FastBytes (n_bytes f) (buf f) + +-- | Gives the UTF-8 encoded bytes corresponding to a 'FastString' +bytesFB :: FastBytes -> [Word8] +bytesFB (FastBytes n_bytes buf) = + inlinePerformIO $ withForeignPtr buf $ \ptr -> + peekArray n_bytes ptr + +hashFB :: FastBytes -> Int +hashFB (FastBytes len buf) + = inlinePerformIO $ withForeignPtr buf $ \ptr -> return $ hashStr ptr len + +lengthFB :: FastBytes -> Int +lengthFB f = fb_n_bytes f + +appendFB :: FastBytes -> FastBytes -> FastBytes +appendFB fb1 fb2 = + inlinePerformIO $ do + r <- mallocForeignPtrBytes len + withForeignPtr r $ \ r' -> do + withForeignPtr (fb_buf fb1) $ \ fb1Ptr -> do + withForeignPtr (fb_buf fb2) $ \ fb2Ptr -> do + copyBytes r' fb1Ptr len1 + copyBytes (advancePtr r' len1) fb2Ptr len2 + return $ foreignPtrToFastBytes r len + where len = len1 + len2 + len1 = fb_n_bytes fb1 + len2 = fb_n_bytes fb2 + + {-| A 'FastString' is an array of bytes, hashed to support fast O(1) comparison. It is also associated with a character encoding, so that @@ -165,8 +230,12 @@ instance Data FastString where dataTypeOf _ = mkNoRepType "FastString" cmpFS :: FastString -> FastString -> Ordering -cmpFS (FastString u1 l1 _ buf1 _) (FastString u2 l2 _ buf2 _) = +cmpFS f1@(FastString u1 _ _ _ _) f2@(FastString u2 _ _ _ _) = if u1 == u2 then EQ else + cmpFB (fastStringToFastBytes f1) (fastStringToFastBytes f2) + +cmpFB :: FastBytes -> FastBytes -> Ordering +cmpFB (FastBytes l1 buf1) (FastBytes l2 buf2) = case unsafeMemcmp buf1 buf2 (min l1 l2) `compare` 0 of LT -> LT EQ -> compare l1 l2 @@ -431,9 +500,7 @@ unpackFS (FastString _ n_bytes _ buf enc) = -- | Gives the UTF-8 encoded bytes corresponding to a 'FastString' bytesFS :: FastString -> [Word8] -bytesFS (FastString _ n_bytes _ buf _) = - inlinePerformIO $ withForeignPtr buf $ \ptr -> - peekArray n_bytes ptr +bytesFS fs = bytesFB $ fastStringToFastBytes fs -- | Returns a Z-encoded version of a 'FastString'. This might be the -- original, if it was already Z-encoded. The first time this |