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use std::cmp;
use misc::Slice;
#[derive(Clone)]
pub struct ZipSlices<T, U> {
t: T,
u: U,
len: usize,
index: usize,
}
impl<'a, 'b, A, B> ZipSlices<&'a [A], &'b [B]> {
#[inline(always)]
pub fn new(a: &'a [A], b: &'b [B]) -> Self {
let minl = cmp::min(a.len(), b.len());
ZipSlices {
t: a,
u: b,
len: minl,
index: 0,
}
}
}
impl<T, U> ZipSlices<T, U>
where T: Slice,
U: Slice
{
#[inline(always)]
pub fn from_slices(a: T, b: U) -> Self {
let minl = cmp::min(a.len(), b.len());
ZipSlices {
t: a,
u: b,
len: minl,
index: 0,
}
}
}
impl<T, U> Iterator for ZipSlices<T, U>
where T: Slice,
U: Slice
{
type Item = (T::Item, U::Item);
#[inline(always)]
fn next(&mut self) -> Option<Self::Item> {
unsafe {
if self.index >= self.len {
None
} else {
let i = self.index;
self.index += 1;
Some((
self.t.get_unchecked(i),
self.u.get_unchecked(i)))
}
}
}
#[inline]
fn size_hint(&self) -> (usize, Option<usize>) {
let len = self.len - self.index;
(len, Some(len))
}
}
impl<T, U> DoubleEndedIterator for ZipSlices<T, U>
where T: Slice,
U: Slice
{
#[inline(always)]
fn next_back(&mut self) -> Option<Self::Item> {
unsafe {
if self.index >= self.len {
None
} else {
self.len -= 1;
let i = self.len;
Some((
self.t.get_unchecked(i),
self.u.get_unchecked(i)))
}
}
}
}
impl<T, U> ExactSizeIterator for ZipSlices<T, U>
where T: Slice,
U: Slice
{}
unsafe impl<T, U> Slice for ZipSlices<T, U>
where T: Slice,
U: Slice
{
type Item = (T::Item, U::Item);
fn len(&self) -> usize {
self.len - self.index
}
unsafe fn get_unchecked(&mut self, i: usize) -> Self::Item {
(self.t.get_unchecked(i),
self.u.get_unchecked(i))
}
}