Modeled in Rust

rust,ignore

# // Copyright 2026 Google LLC
# // SPDX-License-Identifier: Apache-2.0
#
/// Raw pointers
pub struct SelfReferentialBuffer {
    data: [u8; 1024],
    cursor: *mut u8,
}

/// Integer offsets
pub struct SelfReferentialBuffer {
    data: [u8; 1024],
    cursor: usize,
}

/// Pinning
pub struct SelfReferentialBuffer {
    data: [u8; 1024],
    cursor: *mut u8,
    _pin: std::marker::PhantomPinned,
}

Original C++ class definition for reference

cpp,ignore

class SelfReferentialBuffer {
    char data[1024];
    char* cursor;
};

The next few slides show three approaches to creating a Rust type with the same semantics as the original C++.

Using raw pointers: matches C++ very closely, but using the resulting type is extremely hazardous
Storing integer offsets: more natural in Rust, but references need to be created manually
Pinning: allows raw pointers with fewer unsafe blocks

</details>