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//! Type-level bits.
//!
//! These are rather simple and are used as the building blocks of the
//! other number types in this crate.
//!
//!
//! **Type operators** implemented:
//!
//! - From `core::ops`: `BitAnd`, `BitOr`, `BitXor`, and `Not`.
//! - From `typenum`: `Same` and `Cmp`.
use crate::{private::InternalMarker, Cmp, Equal, Greater, Less, NonZero, PowerOfTwo, Zero};
use core::ops::{BitAnd, BitOr, BitXor, Not};
pub use crate::marker_traits::Bit;
/// The type-level bit 0.
#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy, Hash, Debug, Default)]
#[cfg_attr(feature = "scale_info", derive(scale_info::TypeInfo))]
pub struct B0;
impl B0 {
/// Instantiates a singleton representing this bit.
#[inline]
pub fn new() -> B0 {
B0
}
}
/// The type-level bit 1.
#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy, Hash, Debug, Default)]
#[cfg_attr(feature = "scale_info", derive(scale_info::TypeInfo))]
pub struct B1;
impl B1 {
/// Instantiates a singleton representing this bit.
#[inline]
pub fn new() -> B1 {
B1
}
}
impl Bit for B0 {
const U8: u8 = 0;
const BOOL: bool = false;
#[inline]
fn new() -> Self {
Self
}
#[inline]
fn to_u8() -> u8 {
0
}
#[inline]
fn to_bool() -> bool {
false
}
}
impl Bit for B1 {
const U8: u8 = 1;
const BOOL: bool = true;
#[inline]
fn new() -> Self {
Self
}
#[inline]
fn to_u8() -> u8 {
1
}
#[inline]
fn to_bool() -> bool {
true
}
}
impl Zero for B0 {}
impl NonZero for B1 {}
impl PowerOfTwo for B1 {}
/// Not of 0 (!0 = 1)
impl Not for B0 {
type Output = B1;
#[inline]
fn not(self) -> Self::Output {
B1
}
}
/// Not of 1 (!1 = 0)
impl Not for B1 {
type Output = B0;
#[inline]
fn not(self) -> Self::Output {
B0
}
}
/// And with 0 ( 0 & B = 0)
impl<Rhs: Bit> BitAnd<Rhs> for B0 {
type Output = B0;
#[inline]
fn bitand(self, _: Rhs) -> Self::Output {
B0
}
}
/// And with 1 ( 1 & 0 = 0)
impl BitAnd<B0> for B1 {
type Output = B0;
#[inline]
fn bitand(self, _: B0) -> Self::Output {
B0
}
}
/// And with 1 ( 1 & 1 = 1)
impl BitAnd<B1> for B1 {
type Output = B1;
#[inline]
fn bitand(self, _: B1) -> Self::Output {
B1
}
}
/// Or with 0 ( 0 | 0 = 0)
impl BitOr<B0> for B0 {
type Output = B0;
#[inline]
fn bitor(self, _: B0) -> Self::Output {
B0
}
}
/// Or with 0 ( 0 | 1 = 1)
impl BitOr<B1> for B0 {
type Output = B1;
#[inline]
fn bitor(self, _: B1) -> Self::Output {
B1
}
}
/// Or with 1 ( 1 | B = 1)
impl<Rhs: Bit> BitOr<Rhs> for B1 {
type Output = B1;
#[inline]
fn bitor(self, _: Rhs) -> Self::Output {
B1
}
}
/// Xor between 0 and 0 ( 0 ^ 0 = 0)
impl BitXor<B0> for B0 {
type Output = B0;
#[inline]
fn bitxor(self, _: B0) -> Self::Output {
B0
}
}
/// Xor between 1 and 0 ( 1 ^ 0 = 1)
impl BitXor<B0> for B1 {
type Output = B1;
#[inline]
fn bitxor(self, _: B0) -> Self::Output {
B1
}
}
/// Xor between 0 and 1 ( 0 ^ 1 = 1)
impl BitXor<B1> for B0 {
type Output = B1;
#[inline]
fn bitxor(self, _: B1) -> Self::Output {
B1
}
}
/// Xor between 1 and 1 ( 1 ^ 1 = 0)
impl BitXor<B1> for B1 {
type Output = B0;
#[inline]
fn bitxor(self, _: B1) -> Self::Output {
B0
}
}
#[cfg(tests)]
mod tests {
// macro for testing operation results. Uses `Same` to ensure the types are equal and
// not just the values they evaluate to.
macro_rules! test_bit_op {
($op:ident $Lhs:ident = $Answer:ident) => {{
type Test = <<$Lhs as $op>::Output as ::Same<$Answer>>::Output;
assert_eq!(<$Answer as Bit>::to_u8(), <Test as Bit>::to_u8());
}};
($Lhs:ident $op:ident $Rhs:ident = $Answer:ident) => {{
type Test = <<$Lhs as $op<$Rhs>>::Output as ::Same<$Answer>>::Output;
assert_eq!(<$Answer as Bit>::to_u8(), <Test as Bit>::to_u8());
}};
}
#[test]
fn bit_operations() {
test_bit_op!(Not B0 = B1);
test_bit_op!(Not B1 = B0);
test_bit_op!(B0 BitAnd B0 = B0);
test_bit_op!(B0 BitAnd B1 = B0);
test_bit_op!(B1 BitAnd B0 = B0);
test_bit_op!(B1 BitAnd B1 = B1);
test_bit_op!(B0 BitOr B0 = B0);
test_bit_op!(B0 BitOr B1 = B1);
test_bit_op!(B1 BitOr B0 = B1);
test_bit_op!(B1 BitOr B1 = B1);
test_bit_op!(B0 BitXor B0 = B0);
test_bit_op!(B0 BitXor B1 = B1);
test_bit_op!(B1 BitXor B0 = B1);
test_bit_op!(B1 BitXor B1 = B0);
}
}
impl Cmp<B0> for B0 {
type Output = Equal;
#[inline]
fn compare<P: InternalMarker>(&self, _: &B0) -> Self::Output {
Equal
}
}
impl Cmp<B1> for B0 {
type Output = Less;
#[inline]
fn compare<P: InternalMarker>(&self, _: &B1) -> Self::Output {
Less
}
}
impl Cmp<B0> for B1 {
type Output = Greater;
#[inline]
fn compare<P: InternalMarker>(&self, _: &B0) -> Self::Output {
Greater
}
}
impl Cmp<B1> for B1 {
type Output = Equal;
#[inline]
fn compare<P: InternalMarker>(&self, _: &B1) -> Self::Output {
Equal
}
}
use crate::Min;
impl Min<B0> for B0 {
type Output = B0;
#[inline]
fn min(self, _: B0) -> B0 {
self
}
}
impl Min<B1> for B0 {
type Output = B0;
#[inline]
fn min(self, _: B1) -> B0 {
self
}
}
impl Min<B0> for B1 {
type Output = B0;
#[inline]
fn min(self, rhs: B0) -> B0 {
rhs
}
}
impl Min<B1> for B1 {
type Output = B1;
#[inline]
fn min(self, _: B1) -> B1 {
self
}
}
use crate::Max;
impl Max<B0> for B0 {
type Output = B0;
#[inline]
fn max(self, _: B0) -> B0 {
self
}
}
impl Max<B1> for B0 {
type Output = B1;
#[inline]
fn max(self, rhs: B1) -> B1 {
rhs
}
}
impl Max<B0> for B1 {
type Output = B1;
#[inline]
fn max(self, _: B0) -> B1 {
self
}
}
impl Max<B1> for B1 {
type Output = B1;
#[inline]
fn max(self, _: B1) -> B1 {
self
}
}
#[cfg(test)]
mod tests {
#[test]
fn bit_creation() {
{
use crate::{B0, B1};
let _: B0 = B0::new();
let _: B1 = B1::new();
}
{
use crate::{Bit, B0, B1};
let _: B0 = <B0 as Bit>::new();
let _: B1 = <B1 as Bit>::new();
}
}
}