A Rust function for splitting an owned vector into two owned vectors.

split_owned_vec.rs

fn split_owned_vec<T>(mut v: ~[T], index: uint) -> (~[T], ~[T]) {
    assert!(index <= v.len());

    let new_len = v.len() - index;
    let mut new_v = vec::with_capacity(v.len() - index);
    unsafe {
        ptr::copy_nonoverlapping_memory(new_v.as_mut_ptr(), v.as_ptr().offset(index as int), new_len);
        v.set_len(index);
        new_v.set_len(new_len);
    }

    (v, new_v)
}