Fix a rounding bug in display of data sizes

Eg, showImprecise 1 1.99 returned "1.1" rather than "2". The 9 rounded
upward to 10, and that was wrongly used as the decimal, rather than
carrying the 1.

Sponsored-by: Jack Hill on Patreon
This commit is contained in:
Joey Hess 2021-07-30 09:56:04 -04:00
parent 1c4d6dee90
commit 66089e97de
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GPG key ID: DB12DB0FF05F8F38
4 changed files with 80 additions and 3 deletions

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@ -1,6 +1,6 @@
{- numbers for humans
-
- Copyright 2012-2013 Joey Hess <id@joeyh.name>
- Copyright 2012-2021 Joey Hess <id@joeyh.name>
-
- License: BSD-2-clause
-}
@ -11,11 +11,15 @@ module Utility.HumanNumber (showImprecise) where
- of decimal digits. -}
showImprecise :: RealFrac a => Int -> a -> String
showImprecise precision n
| precision == 0 || remainder == 0 = show (round n :: Integer)
| otherwise = show int ++ "." ++ striptrailing0s (pad0s $ show remainder)
| precision == 0 || remainder' == 0 = show (round n :: Integer)
| otherwise = show int' ++ "." ++ striptrailing0s (pad0s $ show remainder')
where
int :: Integer
(int, frac) = properFraction n
remainder = round (frac * 10 ^ precision) :: Integer
(int', remainder')
-- carry the 1
| remainder == 10 ^ precision = (int + 1, 0)
| otherwise = (int, remainder)
pad0s s = replicate (precision - length s) '0' ++ s
striptrailing0s = reverse . dropWhile (== '0') . reverse