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@nikomatsakis
Created September 25, 2018 17:48
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use std::marker::PhantomData;
use std::cmp::Ordering;
use std::ops::{Add, Mul};
pub type True = B1;
pub type False = B0;
pub type U0 = UTerm;
pub type U1 = UInt<UTerm, B1>;
pub trait NonZero {}
pub trait Bit {
}
pub trait Unsigned {
}
#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy, Hash, Debug, Default)]
pub struct B0;
impl B0 {
#[inline]
pub fn new() -> B0 {
B0
}
}
#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy, Hash, Debug, Default)]
pub struct B1;
impl B1 {
#[inline]
pub fn new() -> B1 {
B1
}
}
impl Bit for B0 {
}
impl Bit for B1 {
}
impl NonZero for B1 {}
pub trait PrivatePow<Y, N> {
type Output;
}
pub type PrivatePowOut<A, Y, N> = <A as PrivatePow<Y, N>>::Output;
pub type Add1<A> = <A as Add<::B1>>::Output;
pub type Prod<A, B> = <A as Mul<B>>::Output;
pub type Square<A> = <A as Mul>::Output;
pub type Sum<A, B> = <A as Add<B>>::Output;
#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy, Hash, Debug, Default)]
pub struct UTerm;
impl UTerm {
#[inline]
pub fn new() -> UTerm {
UTerm
}
}
impl Unsigned for UTerm {
}
#[derive(Eq, PartialEq, Ord, PartialOrd, Clone, Copy, Hash, Debug, Default)]
pub struct UInt<U, B> {
_marker: PhantomData<(U, B)>,
}
impl<U: Unsigned, B: Bit> UInt<U, B> {
#[inline]
pub fn new() -> UInt<U, B> {
UInt {
_marker: PhantomData,
}
}
}
impl<U: Unsigned, B: Bit> Unsigned for UInt<U, B> {
}
impl<U: Unsigned, B: Bit> NonZero for UInt<U, B> {}
impl Add<B0> for UTerm {
type Output = UTerm;
fn add(self, _: B0) -> Self::Output {
UTerm
}
}
impl<U: Unsigned, B: Bit> Add<B0> for UInt<U, B> {
type Output = UInt<U, B>;
fn add(self, _: B0) -> Self::Output {
UInt::new()
}
}
impl<U: Unsigned> Add<U> for UTerm {
type Output = U;
fn add(self, _: U) -> Self::Output {
unsafe { ::std::mem::uninitialized() }
}
}
impl<U: Unsigned, B: Bit> Mul<B0> for UInt<U, B> {
type Output = UTerm;
fn mul(self, _: B0) -> Self::Output {
UTerm
}
}
impl<U: Unsigned, B: Bit> Mul<B1> for UInt<U, B> {
type Output = UInt<U, B>;
fn mul(self, _: B1) -> Self::Output {
UInt::new()
}
}
impl<U: Unsigned> Mul<U> for UTerm {
type Output = UTerm;
fn mul(self, _: U) -> Self::Output {
UTerm
}
}
impl<Ul: Unsigned, B: Bit, Ur: Unsigned> Mul<UInt<Ur, B>> for UInt<Ul, B0>
where
Ul: Mul<UInt<Ur, B>>,
{
type Output = UInt<Prod<Ul, UInt<Ur, B>>, B0>;
fn mul(self, _: UInt<Ur, B>) -> Self::Output {
unsafe { ::std::mem::uninitialized() }
}
}
pub trait Pow<Exp> {
type Output;
}
impl<X: Unsigned, N: Unsigned> Pow<N> for X
where
X: PrivatePow<U1, N>,
{
type Output = PrivatePowOut<X, U1, N>;
}
impl<Y: Unsigned, X: Unsigned> PrivatePow<Y, U0> for X {
type Output = Y;
}
impl<Y: Unsigned, X: Unsigned> PrivatePow<Y, U1> for X
where
X: Mul<Y>,
{
type Output = Prod<X, Y>;
}
impl<Y: Unsigned, U: Unsigned, B: Bit, X: Unsigned> PrivatePow<Y, UInt<UInt<U, B>, B0>> for X
where
X: Mul,
Square<X>: PrivatePow<Y, UInt<U, B>>,
{
type Output = PrivatePowOut<Square<X>, Y, UInt<U, B>>;
}
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