Crate buffering_nocopy_macro

Structure

This crate provides the procedural macro NoCopy to the buffering crate. Buffering is feature flagged to be able to use only this macro so there is no reason for this to be used outside of that crate.

Restrictions

This only works currently if the following conditions are met for the data type:

• It is a struct with named fields
• The type of each field is stack-allocatable and the size is known at compile time, or in other words, the size does not change

Provided methods

Each struct to which NoCopy is applied will generate a union type to be used for buffer operations. Traversal works like this:

• The union can be initialized either as a struct assigned to the .structure() field of the union or using the MyUnionType::new_buffer() method and providing a slice
• The union also provides methods .get_your_field_name and .set_your_field_name that are generated per struct field (and where your_field_name is replaced by the actual name of the field)
• Each getter and setter will respect endianness set by the corresponding field attribute provided in the original struct

Recognized attributes

Attributes can be added to fields to specify whether they should be interpreted as big endian values or little endian values in the form #[endian = "big"] or #[endian = "little"]. If neither is specified, native endian is assumed. It is provided on a per-field basis due to restrictions on what types provide the to_be, etc. methods. These fields should be used when doing internet networking to assure cross-architecture portability. Protocols that assume native endian buffer representation do not need these attributes. A struct-level attribute is also provided as #[name = "MyUnionNameHere"] to override the autogenerated name for the resulting union.

Derive Macros

NoCopy

Procedural macro that will derive getters and setters with appropriate endianness for every field defined in the struct