flat-0.4.4.0.0.0.0.2: Principled and efficient bit-oriented binary serialization.
Safe Haskell Safe-Inferred
Language Haskell2010

Data.ZigZag

Description

ZigZag encoding of signed integrals.

Synopsis

Documentation

class ( Integral signed, Integral unsigned) => ZigZag signed unsigned | unsigned -> signed, signed -> unsigned where Source #

Convert between a signed integral and the corresponding ZigZag encoded unsigned integral (e.g. between Int8 and Word8 or Integral and Natural).

Allow conversion only between compatible types, invalid conversions produce a type error:

zigZag (-1::Int64) :: Word32
...
... Couldn't match type ...
...
>>> zigZag (0::Int8)
0
>>> zigZag (-1::Int16)
1
>>> zigZag (1::Int32)
2
>>> zigZag (-2::Int16)
3
>>> zigZag (-50::Integer)
99
>>> zigZag (50::Integer)
100
>>> zigZag (64::Integer)
128
>>> zigZag (-256::Integer)
511
>>> zigZag (256::Integer)
512
>>> map zigZag [-3..3::Integer]
[5,3,1,0,2,4,6]
>>> map zagZig [0..6::Word8]
[0,-1,1,-2,2,-3,3]
\(f::Integer) -> zagZig (zigZag f) == f

+++ OK, passed 100 tests.

\(f::Natural) -> zigZag (zagZig f) == f

+++ OK, passed 100 tests.

\(f::Int8) -> zagZig (zigZag f) == f

+++ OK, passed 100 tests. prop> (f::Word8) -> zigZag (zagZig f) == f +++ OK, passed 100 tests. prop> (s::Int8) -> zigZag s == fromIntegral (zigZag (fromIntegral s :: Integer)) +++ OK, passed 100 tests. prop> (u::Word8) -> zagZig u == fromIntegral (zagZig (fromIntegral u :: Natural)) +++ OK, passed 100 tests.

\(f::Int64) -> zagZig (zigZag f) == f

+++ OK, passed 100 tests. prop> (f::Word64) -> zigZag (zagZig f) == f +++ OK, passed 100 tests. prop> (s::Int64) -> zigZag s == fromIntegral (zigZag (fromIntegral s :: Integer)) +++ OK, passed 100 tests. prop> (u::Word64) -> zagZig u == fromIntegral (zagZig (fromIntegral u :: Natural)) +++ OK, passed 100 tests.

Minimal complete definition

Nothing

Methods

zigZag :: signed -> unsigned Source #

default zigZag :: FiniteBits signed => signed -> unsigned Source #

zagZig :: unsigned -> signed Source #

default zagZig :: Bits unsigned => unsigned -> signed Source #