sorted 0.2.0

Provides compile time guarantees for sorted sequences.
Documentation 
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use std::cmp::Ordering;
use super::{SortOrder, SortedIterator};

pub struct Intersection<I, J>
    where I: SortedIterator,
          I::Ordering: SortOrder<I::Item>,
          J: SortedIterator<Item = I::Item, Ordering = I::Ordering>
{
    i: I,
    j: J,
    a: Option<I::Item>,
    b: Option<J::Item>,
}


impl<I, J> SortedIterator for Intersection<I, J>
    where I: SortedIterator,
          I::Ordering: SortOrder<I::Item>,
          J: SortedIterator<Item = I::Item, Ordering = I::Ordering>
{
    type Ordering = I::Ordering;
}

impl<I, J> Iterator for Intersection<I, J>
    where I: SortedIterator,
          I::Ordering: SortOrder<I::Item>,
          J: SortedIterator<Item = I::Item, Ordering = I::Ordering>
{
    type Item = I::Item;

    fn next(&mut self) -> Option<Self::Item> {
        loop {
            let a = self.a.take().or_else(|| self.i.next());
            let b = self.b.take().or_else(|| self.j.next());
            match (a, b) {
                (Some(a), Some(b)) => {
                    match I::Ordering::cmp(&a, &b) {
                        Ordering::Equal => return Some(a),
                        Ordering::Less => self.b = Some(b),
                        Ordering::Greater => self.a = Some(a),
                    }
                }
                _ => return None,
            }
        }
    }
}


pub trait IntersectionExt
    where Self: SortedIterator + Sized,
          Self::Ordering: SortOrder<Self::Item>
{
    fn intersection<J>(self, J) -> Intersection<Self, J>
        where J: SortedIterator<Item = Self::Item, Ordering = Self::Ordering>;
}

impl<I> IntersectionExt for I
    where I: SortedIterator,
          I::Ordering: SortOrder<I::Item>
{
    fn intersection<J>(self, j: J) -> Intersection<Self, J>
        where J: SortedIterator<Item = Self::Item, Ordering = Self::Ordering>
    {
        Intersection {
            i: self,
            j,
            a: None,
            b: None,
        }
    }
}