use std::default::Default;
use std::fmt;
use std::iter::{FromIterator, IntoIterator};
use crate::Commute;
#[derive(Clone)]
pub struct MinMax<T> {
len: u64,
min: Option<T>,
max: Option<T>,
}
impl<T: PartialOrd + Clone> MinMax<T> {
#[must_use]
pub fn new() -> MinMax<T> {
Default::default()
}
#[inline]
pub fn add(&mut self, sample: T) {
self.len += 1;
if self.min.as_ref().map_or(true, |v| &sample < v) {
self.min = Some(sample.clone());
}
if self.max.as_ref().map_or(true, |v| &sample > v) {
self.max = Some(sample);
}
}
#[inline]
#[must_use]
pub const fn min(&self) -> Option<&T> {
self.min.as_ref()
}
#[inline]
#[must_use]
pub const fn max(&self) -> Option<&T> {
self.max.as_ref()
}
#[inline]
#[must_use]
pub const fn len(&self) -> usize {
self.len as usize
}
#[inline]
#[must_use]
pub const fn is_empty(&self) -> bool {
self.len == 0
}
}
impl<T: PartialOrd> Commute for MinMax<T> {
#[inline]
fn merge(&mut self, v: MinMax<T>) {
self.len += v.len;
if self.min.is_none() || (v.min.is_some() && v.min < self.min) {
self.min = v.min;
}
if self.max.is_none() || (v.max.is_some() && v.max > self.max) {
self.max = v.max;
}
}
}
impl<T: PartialOrd> Default for MinMax<T> {
#[inline]
fn default() -> MinMax<T> {
MinMax {
len: 0,
min: None,
max: None,
}
}
}
impl<T: fmt::Debug> fmt::Debug for MinMax<T> {
#[inline]
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match (&self.min, &self.max) {
(Some(min), Some(max)) => {
write!(f, "[{min:?}, {max:?}]")
}
(&None, &None) => write!(f, "N/A"),
_ => unreachable!(),
}
}
}
impl<T: PartialOrd + Clone> FromIterator<T> for MinMax<T> {
#[inline]
fn from_iter<I: IntoIterator<Item = T>>(it: I) -> MinMax<T> {
let mut v = MinMax::new();
v.extend(it);
v
}
}
impl<T: PartialOrd + Clone> Extend<T> for MinMax<T> {
#[inline]
fn extend<I: IntoIterator<Item = T>>(&mut self, it: I) {
for sample in it {
self.add(sample);
}
}
}
#[cfg(test)]
mod test {
use super::MinMax;
use crate::Commute;
#[test]
fn minmax() {
let minmax: MinMax<u32> = vec![1u32, 4, 2, 3, 10].into_iter().collect();
assert_eq!(minmax.min(), Some(&1u32));
assert_eq!(minmax.max(), Some(&10u32));
}
#[test]
fn minmax_empty() {
let minmax: MinMax<u32> = MinMax::new();
assert!(minmax.is_empty());
}
#[test]
fn minmax_merge_empty() {
let mut mx1: MinMax<u32> = vec![1, 4, 2, 3, 10].into_iter().collect();
assert_eq!(mx1.min(), Some(&1u32));
assert_eq!(mx1.max(), Some(&10u32));
mx1.merge(MinMax::default());
assert_eq!(mx1.min(), Some(&1u32));
assert_eq!(mx1.max(), Some(&10u32));
}
}