Empty { .. } => (None, None), // empty iterators yield no values
NonEmpty { ref mut start, ref mut end } => {
- let one = A::one();
- if start <= end {
+ if start == end {
+ (Some(mem::replace(end, A::one())), Some(mem::replace(start, A::one())))
+ } else if start < end {
+ let one = A::one();
let mut n = &*start + &one;
mem::swap(&mut n, start);
// ^ are we done yet?
Some(n)) // < the value to output
} else {
- (Some(mem::replace(start, one)), None)
+ (Some(mem::replace(start, A::one())), None)
}
}
};
Empty { .. } => return None,
NonEmpty { ref mut start, ref mut end } => {
- let one = A::one();
- if start <= end {
+ if start == end {
+ (Some(mem::replace(start, A::one())), Some(mem::replace(end, A::one())))
+ } else if start < end {
+ let one = A::one();
let mut n = &*end - &one;
mem::swap(&mut n, end);
(if n == *start { Some(mem::replace(start, one)) } else { None },
Some(n))
} else {
- (Some(mem::replace(end, one)), None)
+ (Some(mem::replace(end, A::one())), None)
}
}
};