diff options
Diffstat (limited to 'compiler/utils/FastString.lhs')
| -rw-r--r-- | compiler/utils/FastString.lhs | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/compiler/utils/FastString.lhs b/compiler/utils/FastString.lhs index 29c7788c2f..055f921213 100644 --- a/compiler/utils/FastString.lhs +++ b/compiler/utils/FastString.lhs @@ -449,7 +449,18 @@ zEncodeFS fs@(FastString _ _ _ _ enc) = return efs appendFS :: FastString -> FastString -> FastString -appendFS fs1 fs2 = mkFastString (unpackFS fs1 ++ unpackFS fs2) +appendFS fs1 fs2 = + inlinePerformIO $ do + r <- mallocForeignPtrBytes len + withForeignPtr r $ \ r' -> do + withForeignPtr (buf fs1) $ \ fs1Ptr -> do + withForeignPtr (buf fs2) $ \ fs2Ptr -> do + copyBytes r' fs1Ptr len1 + copyBytes (advancePtr r' len1) fs2Ptr len2 + mkFastStringForeignPtr r' r len + where len = len1 + len2 + len1 = lengthFS fs1 + len2 = lengthFS fs2 concatFS :: [FastString] -> FastString concatFS ls = mkFastString (Prelude.concat (map unpackFS ls)) -- ToDo: do better |