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use core::{fmt, ops::Neg};
use num_traits::{CheckedAdd, CheckedSub, Num};
use super::{ShiftTernary, Trit, Utrit};
use crate::convert;
#[derive(Copy, Clone, Debug, Eq, Hash, Ord, PartialEq, PartialOrd)]
#[repr(i8)]
#[allow(missing_docs)]
pub enum Btrit {
NegOne = -1,
Zero = 0,
PlusOne = 1,
}
impl fmt::Display for Btrit {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}", *self as i8)
}
}
impl From<Btrit> for i8 {
fn from(value: Btrit) -> Self {
value as i8
}
}
impl ShiftTernary for Btrit {
type Target = Utrit;
fn shift(self) -> Self::Target {
use Btrit::*;
match self {
NegOne => Self::Target::Zero,
Zero => Self::Target::One,
PlusOne => Self::Target::Two,
}
}
}
impl Neg for Btrit {
type Output = Self;
fn neg(self) -> Self {
use Btrit::*;
match self {
NegOne => PlusOne,
Zero => Zero,
PlusOne => NegOne,
}
}
}
impl Trit for Btrit {
fn checked_increment(self) -> Option<Self> {
match self {
Btrit::NegOne => Some(Btrit::Zero),
Btrit::Zero => Some(Btrit::PlusOne),
Btrit::PlusOne => None,
}
}
fn zero() -> Self {
Self::Zero
}
fn as_arbitrary_ref<'a>(&self) -> &'a Self {
static NEG_ONE: Btrit = Btrit::NegOne;
static ZERO: Btrit = Btrit::Zero;
static PLUS_ONE: Btrit = Btrit::PlusOne;
match self {
Btrit::NegOne => &NEG_ONE,
Btrit::Zero => &ZERO,
Btrit::PlusOne => &PLUS_ONE,
}
}
fn add_to_num<I: Num + CheckedAdd + CheckedSub>(&self, n: I) -> Result<I, convert::Error> {
match self {
Btrit::NegOne => n.checked_sub(&I::one()).ok_or(convert::Error::Underflow),
Btrit::Zero => Ok(n),
Btrit::PlusOne => n.checked_add(&I::one()).ok_or(convert::Error::Overflow),
}
}
}
impl TryFrom<i8> for Btrit {
type Error = ();
fn try_from(x: i8) -> Result<Self, Self::Error> {
let converted = match x {
-1 => Btrit::NegOne,
0 => Btrit::Zero,
1 => Btrit::PlusOne,
_ => return Err(()),
};
Ok(converted)
}
}
impl TryFrom<u8> for Btrit {
type Error = ();
fn try_from(x: u8) -> Result<Self, Self::Error> {
let converted = match x {
0 => Btrit::Zero,
1 => Btrit::PlusOne,
_ => return Err(()),
};
Ok(converted)
}
}
