pub trait VecExt<T> {
fn copy_overlapped(&mut self, src: usize, dst: usize, len: usize);
}
pub trait VecExt2<T> {
fn pop_first(&mut self) -> Option<T>;
}
impl<T: Copy> VecExt<T> for Vec<T> {
fn copy_overlapped(&mut self, src: usize, dst: usize, mut len: usize) {
let mut src = src.min(self.len());
let mut dst = dst.min(self.len());
if dst > src {
while len > 0 {
let preceding = (dst - src).min(len);
for i in 0..preceding {
self[dst + i] = self[src + i];
}
len -= preceding;
src += preceding;
dst += preceding;
}
} else {
for i in 0..len {
self[dst + i] = self[src + i];
}
}
}
}
impl<T> VecExt2<T> for Vec<T> {
fn pop_first(&mut self) -> Option<T> {
if self.is_empty() {
None
} else {
Some(self.remove(0))
}
}
}