| Safe Haskell | Safe |
|---|---|
| Language | Haskell98 |
Data.Bits.Compat
Synopsis
- module Data.Bits
- bitDefault :: (Bits a, Num a) => Int -> a
- testBitDefault :: (Bits a, Num a) => a -> Int -> Bool
- popCountDefault :: (Bits a, Num a) => a -> Int
- toIntegralSized :: (Integral a, Integral b, Bits a, Bits b) => a -> Maybe b
Documentation
module Data.Bits
bitDefault :: (Bits a, Num a) => Int -> a #
testBitDefault :: (Bits a, Num a) => a -> Int -> Bool #
Default implementation for testBit.
Note that: testBitDefault x i = (x .&. bit i) /= 0
Since: base-4.6.0.0
popCountDefault :: (Bits a, Num a) => a -> Int #
Default implementation for popCount.
This implementation is intentionally naive. Instances are expected to provide an optimized implementation for their size.
Since: base-4.6.0.0
toIntegralSized :: (Integral a, Integral b, Bits a, Bits b) => a -> Maybe b #
Attempt to convert an Integral type a to an Integral type b using
the size of the types as measured by Bits methods.
A simpler version of this function is:
toIntegral :: (Integral a, Integral b) => a -> Maybe b
toIntegral x
| toInteger x == y = Just (fromInteger y)
| otherwise = Nothing
where
y = toInteger xThis version requires going through Integer, which can be inefficient.
However, toIntegralSized is optimized to allow GHC to statically determine
the relative type sizes (as measured by bitSizeMaybe and isSigned) and
avoid going through Integer for many types. (The implementation uses
fromIntegral, which is itself optimized with rules for base types but may
go through Integer for some type pairs.)
Since: base-4.8.0.0