Basic data layout

For my personal opinion, we need to use the knowledge to make effect to industry. People still limit by the energy and time.

I follow this idea

What’s the tag of the enum in Rust?

The tag help us to create less junk.

What’s the junk of data layout?

This need to look at how an enums is laid out in memory.

• allocating the empty in memory

Null pointer optimization

Make the whole object be 0 if the pointer is null, help avoid waste more even space.

Rust enum layout totally unspecified to support this kind of optimization.

null pointer lets &, &mut, Box, Rc, Arc, Vec and several other important types in Rust have no overhead when put in an Option(this should be more explain).

How to avoid extra junk?

• use the list never allocates extra junk(the data-structure should use the type which implements null pointer optimization)
• the elements are uniformly allocated

Source Of Read

• rust unofficial