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use crate::at::At;
use core::ops;
impl<T> At<usize> for [T] {
type View = T;
fn access_at<R, F>(&mut self, i: usize, f: F) -> Option<R> where
F: FnOnce(&mut T) -> R
{
match self.get_mut(i) {
None => None,
Some(x) => Some(f(x)),
}
}
}
impl<T> At<ops::Range<usize>> for [T] {
type View = [T];
fn access_at<R, F>(&mut self, i: ops::Range<usize>, f: F) -> Option<R> where
F: FnOnce(&mut Self::View) -> R
{
if i.end > self.len() { return None; }
if i.start > i.end { return None; }
Some(f(&mut self[i]))
}
}
impl<T> At<ops::RangeFrom<usize>> for [T] {
type View = [T];
fn access_at<R, F>(&mut self, i: ops::RangeFrom<usize>, f: F) -> Option<R> where
F: FnOnce(&mut Self::View) -> R
{
if i.start > self.len() { return None; }
Some(f(&mut self[i]))
}
}
impl<T> At<ops::RangeFull> for [T] {
type View = [T];
fn access_at<R, F>(&mut self, _: ops::RangeFull, f: F) -> Option<R> where
F: FnOnce(&mut Self::View) -> R
{
Some(f(self))
}
}
impl<T> At<ops::RangeInclusive<usize>> for [T] {
type View = [T];
fn access_at<R, F>(&mut self, i: ops::RangeInclusive<usize>, f: F) -> Option<R> where
F: FnOnce(&mut Self::View) -> R
{
let (start, end) = (*i.start(), *i.end());
if end >= self.len() { return None; }
if start > end+1 { return None; }
Some(f(&mut self[i]))
}
}
impl<T> At<ops::RangeTo<usize>> for [T] {
type View = [T];
fn access_at<R, F>(&mut self, i: ops::RangeTo<usize>, f: F) -> Option<R> where
F: FnOnce(&mut Self::View) -> R
{
if i.end > self.len() { return None; }
Some(f(&mut self[i]))
}
}
impl<T> At<ops::RangeToInclusive<usize>> for [T] {
type View = [T];
fn access_at<R, F>(&mut self, i: ops::RangeToInclusive<usize>, f: F) -> Option<R> where
F: FnOnce(&mut Self::View) -> R
{
if i.end >= self.len() { return None; }
Some(f(&mut self[i]))
}
}