Trait Limits

Source

pub trait Limits: Copy {
    // Required method
    fn supports_hash(self, h: TpmiAlgHash) -> bool;

    // Provided method
    fn max_digest_size(self) -> usize { ... }
}

Expand description

Allows an implementation to restrict which values it can Marshal and Unmarshal.

This trait enables different implementations to share the same core type definitions while selectively supporting only a subset of variants. This selection can be enforced either at compile time or at runtime.

This approach is important for two main reasons:

ABI Stability: It avoids the many compile-time #defines found in C implementations. Those defines often alter structure layouts, leading to API and ABI incompatibilities between libraries compiled with different options.
Code Size: Restricting which algorithms and types the marshaling code must support can significantly reduce the final binary size, which is critical for constrained environments.