You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: slice_ext.rs
    path of file: ./repos/occlum/src/libos/src/untrusted
    
    the code of the file until where you have to start completion: /// Extension traits for slices
use super::*;
use std::ptr;

/// An extension trait for slice to get its _const_ pointer and lengt
    
    fn as_mut_ptr_and_len(&mut self) -> (*mut T, usize) {
        if self.len() > 0 {
            (self.as_mut_ptr(), self.len())
        } else {
            (ptr::null_mut(), 0)
        }
    }