Trait Tag

pub unsafe trait Tag: Copy {
    const BITS: u32;

    // Required methods
    fn into_usize(self) -> usize;
    unsafe fn from_usize(tag: usize) -> Self;
}

This describes tags that the TaggedPtr struct can hold.

Safety

The BITS constant must be correct.

No more than BITS least-significant bits may be set in the returned usize.

Required Associated Constants

const BITS: u32

Number of least-significant bits in the return value of into_usize which may be non-zero. In other words this is the bit width of the value.

Required Methods

fn into_usize(self) -> usize

Turns this tag into an integer.

The inverse of this function is from_usize.

This function guarantees that only the least-significant Self::BITS bits can be non-zero.

unsafe fn from_usize(tag: usize) -> Self

Re-creates the tag from the integer returned by into_usize.

Safety

The passed tag must be returned from into_usize.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl Tag for ParamTag