Crate rfc2580

An (extended) implementation of the proposal of RFC 2580.

Purpose.

The purpose of this crate is dual:

1. The ability to take apart a fat pointer, and put it back together later.
2. The ability to do so for any pointer, be it a pointer to trait, slice, or a regular Sized type.

The second ability, in particular, is not brushed upon by RFC 2580 as far as I can tell, yet is critical in enabling uniform handling of *const T regardless of the nature of T.

Usage.

The traits defined by this crate -- Pointee and MetaData -- are already implemented for all types, and are generally not expected to be used by themselves apart from bounds.

Instead, the high-level API of this crate are the two functions:

• into_raw_parts, which splits a pointer into meta-data and pointer-to-data parts.
• from_raw_parts, which joins back the two parts to recreate a (possibly fat) pointer.

Safety.

This crate operates entirely in terms of pointers; the operations it performs are safe even in the presence of dangling pointers, or null pointers.

In return, whether the pointers it recreates are safe to dereference or not hinges entirely on whether the pointer to data used to recreate the full pointer is safe to dereference.

Example.

A simple example showing how to take apart a pointer and recreate it.

use rfc2580::{from_raw_parts, into_raw_parts};

let array = [1; 4];
let slice = &array[..];
let (meta, data) = into_raw_parts(slice as *const [i32]);

let reconstituted = from_raw_parts(meta, data);

assert_eq!(slice as *const [i32], reconstituted);

Structs

DynMetaData	DynMetaData.
SizedMetaData	SizedMetaData.
SliceMetaData	SliceMetaData.

Traits

AlignedMetaData	AlignedMetaData.
MetaData	MetaData.
Pointee	Pointee.

Functions

from_raw_parts	Joins a meta-data and data-pointer parts into a pointer to the appropriate type.
into_raw_parts	Splits any pointer into its meta-data and data-pointer parts.