Rust unnecessary memory copy?

user_9438342 0
Viewed 170

In order to implement a iterator for a struct that has a slice with a lifetime, I had to do


struct S<'a, T> {
    inner: &'a mut [T],
}

impl<'a, T> Iterator for S<'a, T> {
    type Item = &'a mut T;

    fn next(&mut self) -> Option<Self::Item> {
        let temp = std::mem::take(&mut self.inner);
        let (first, rest) = temp.split_first_mut()?;
        self.inner = rest;
        Some(first)
    }
}

While writing this code, i realized lifetime enforces additional memory copy(mem::take) that would be unnecessary in C or C++. Am i missing something here or is this a small price that rust pays for the lifetime?

rust
1 Answers
  1. Unnecessary copies are to be optimized by LLVM.
  2. mem::take<T> requires that T impls Default so do not regard it as a generic solution.
user_86750260
Related