use crate::{Driver, ValueGenerator};
use core::{
marker::PhantomData,
ops::{Bound, RangeBounds},
};
pub(crate) trait BoundExt<T> {
fn as_ref(&self) -> Bound<&T>;
fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Bound<U>;
}
impl<T> BoundExt<T> for Bound<T> {
fn as_ref(&self) -> Bound<&T> {
match self {
Self::Excluded(v) => Bound::Excluded(v),
Self::Included(v) => Bound::Included(v),
Self::Unbounded => Bound::Unbounded,
}
}
fn map<U, F: FnOnce(T) -> U>(self, f: F) -> Bound<U> {
match self {
Self::Excluded(v) => Bound::Excluded(f(v)),
Self::Included(v) => Bound::Included(f(v)),
Self::Unbounded => Bound::Unbounded,
}
}
}
pub trait BoundedValue<B = Self>: Sized {
fn gen_bounded<D: Driver>(driver: &mut D, min: Bound<&B>, max: Bound<&B>) -> Option<Self>;
fn mutate_bounded<D: Driver>(
&mut self,
driver: &mut D,
min: Bound<&B>,
max: Bound<&B>,
) -> Option<()> {
*self = Self::gen_bounded(driver, min, max)?;
Some(())
}
}
macro_rules! range_generator {
($ty:ident) => {
impl<T: BoundedValue> ValueGenerator for core::ops::$ty<T> {
type Output = T;
fn generate<D: Driver>(&self, driver: &mut D) -> Option<Self::Output> {
let min = self.start_bound();
let max = self.end_bound();
T::gen_bounded(driver, min, max)
}
fn mutate<D: Driver>(&self, driver: &mut D, value: &mut Self::Output) -> Option<()> {
let min = self.start_bound();
let max = self.end_bound();
value.mutate_bounded(driver, min, max)
}
}
};
}
range_generator!(Range);
range_generator!(RangeFrom);
range_generator!(RangeInclusive);
range_generator!(RangeTo);
range_generator!(RangeToInclusive);
#[derive(Debug)]
pub struct BoundedGenerator<T, B> {
range_bounds: B,
output: PhantomData<T>,
}
impl<T: BoundedValue, B: RangeBounds<T>> BoundedGenerator<T, B> {
pub fn new(range_bounds: B) -> Self {
BoundedGenerator {
range_bounds,
output: PhantomData,
}
}
pub fn bounds<NewB: RangeBounds<T>>(self, range_bounds: NewB) -> BoundedGenerator<T, NewB> {
BoundedGenerator {
range_bounds,
output: PhantomData,
}
}
}
impl<T: BoundedValue, B: RangeBounds<T>> ValueGenerator for BoundedGenerator<T, B> {
type Output = T;
fn generate<D: Driver>(&self, driver: &mut D) -> Option<Self::Output> {
let min = self.range_bounds.start_bound();
let max = self.range_bounds.end_bound();
T::gen_bounded(driver, min, max)
}
fn mutate<D: Driver>(&self, driver: &mut D, value: &mut Self::Output) -> Option<()> {
let min = self.range_bounds.start_bound();
let max = self.range_bounds.end_bound();
value.mutate_bounded(driver, min, max)
}
}
#[test]
fn with_bounds_test() {
let _ = generator_test!(gen::<u8>().with().bounds(0..32));
}