{-# LANGUAGE CPP #-} -- | -- Module: Data.Text.Internal.Builder.RealFloat.Functions -- Copyright: (c) The University of Glasgow 1994-2002 -- License: see libraries/base/LICENSE -- -- /Warning/: this is an internal module, and does not have a stable -- API or name. Functions in this module may not check or enforce -- preconditions expected by public modules. Use at your own risk! module Data.Text.Internal.Builder.RealFloat.Functions ( roundTo ) where roundTo :: Int -> [Int] -> (Int,[Int]) #if MIN_VERSION_base(4,6,0) roundTo d is = case f d True is of x@(0,_) -> x (1,xs) -> (1, 1:xs) _ -> error "roundTo: bad Value" where b2 = base `quot` 2 f n _ [] = (0, replicate n 0) f 0 e (x:xs) | x == b2 && e && all (== 0) xs = (0, []) -- Round to even when at exactly half the base | otherwise = (if x >= b2 then 1 else 0, []) f n _ (i:xs) | i' == base = (1,0:ds) | otherwise = (0,i':ds) where (c,ds) = f (n-1) (even i) xs i' = c + i base = 10 #else roundTo d is = case f d is of x@(0,_) -> x (1,xs) -> (1, 1:xs) _ -> error "roundTo: bad Value" where f n [] = (0, replicate n 0) f 0 (x:_) = (if x >= 5 then 1 else 0, []) f n (i:xs) | i' == 10 = (1,0:ds) | otherwise = (0,i':ds) where (c,ds) = f (n-1) xs i' = c + i #endif