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Diffstat (limited to 'vendor/ref-cast/src/lib.rs')
| -rw-r--r-- | vendor/ref-cast/src/lib.rs | 194 |
1 files changed, 0 insertions, 194 deletions
diff --git a/vendor/ref-cast/src/lib.rs b/vendor/ref-cast/src/lib.rs deleted file mode 100644 index 71914feb..00000000 --- a/vendor/ref-cast/src/lib.rs +++ /dev/null @@ -1,194 +0,0 @@ -//! [![github]](https://github.com/dtolnay/ref-cast) [![crates-io]](https://crates.io/crates/ref-cast) [![docs-rs]](https://docs.rs/ref-cast) -//! -//! [github]: https://img.shields.io/badge/github-8da0cb?style=for-the-badge&labelColor=555555&logo=github -//! [crates-io]: https://img.shields.io/badge/crates.io-fc8d62?style=for-the-badge&labelColor=555555&logo=rust -//! [docs-rs]: https://img.shields.io/badge/docs.rs-66c2a5?style=for-the-badge&labelColor=555555&logo=docs.rs -//! -//! <br> -//! -//! This crate provides a derive macro for generating safe conversions from `&T` -//! to `&U` where the struct `U` contains a single field of type `T`. -//! -//! # Basic example -//! -//! ``` -//! use ref_cast::RefCast; -//! -//! #[derive(RefCast)] -//! #[repr(transparent)] -//! struct U(String); -//! -//! fn main() { -//! let s = String::new(); -//! -//! // Safely cast from `&String` to `&U`. -//! let u = U::ref_cast(&s); -//! } -//! ``` -//! -//! Note that `#[repr(transparent)]` is required in order for the conversion to -//! be sound. The derive macro will refuse to compile if that is not present. -//! -//! # Realistic example -//! -//! Suppose we have a multidimensional array represented in a flat buffer in -//! row-major order for performance reasons, but we want to expose an indexing -//! operation that works in column-major order because it is more intuitive in -//! the context of our application. -//! -//! ``` -//! const MAP_WIDTH: usize = 4; -//! -//! struct Tile(u8); -//! -//! struct TileMap { -//! storage: Vec<Tile>, -//! } -//! -//! // `tilemap[x][y]` should give us `tilemap.storage[y * MAP_WIDTH + x]`. -//! ``` -//! -//! The signature of the [`Index`] trait in Rust is such that the output is -//! forced to be borrowed from the type being indexed. So something like the -//! following is not going to work. -//! -//! [`Index`]: core::ops::Index -//! -//! ``` -//! # const MAP_WIDTH: usize = 4; -//! # -//! # struct Tile(u8); -//! # -//! # struct TileMap { -//! # storage: Vec<Tile>, -//! # } -//! # -//! struct Column<'a> { -//! tilemap: &'a TileMap, -//! x: usize, -//! } -//! -//! # mod index1 { -//! # use super::{TileMap, Column, MAP_WIDTH}; -//! # -//! # trait Index<Idx> { -//! # fn index(&self, idx: Idx) -> Column; -//! # } -//! # -//! // Does not work! The output of Index must be a reference that is -//! // borrowed from self. Here the type Column is not a reference. -//! impl Index<usize> for TileMap { -//! fn index(&self, x: usize) -> Column { -//! assert!(x < MAP_WIDTH); -//! Column { tilemap: self, x } -//! } -//! } -//! # } -//! -//! # mod index2 { -//! # use super::{Column, Tile, MAP_WIDTH}; -//! # use std::ops::Index; -//! # -//! impl<'a> Index<usize> for Column<'a> { -//! # type Output = Tile; -//! fn index(&self, y: usize) -> &Tile { -//! &self.tilemap.storage[y * MAP_WIDTH + self.x] -//! } -//! } -//! # } -//! # -//! # fn main() {} -//! ``` -//! -//! Here is a working approach using `RefCast`. -//! -//! ``` -//! # use ref_cast::RefCast; -//! # use std::ops::Index; -//! # -//! # const MAP_WIDTH: usize = 4; -//! # -//! # struct Tile(u8); -//! # -//! # struct TileMap { -//! # storage: Vec<Tile>, -//! # } -//! # -//! #[derive(RefCast)] -//! #[repr(transparent)] -//! struct Strided([Tile]); -//! -//! // Implement `tilemap[x][y]` as `tilemap[x..][y * MAP_WIDTH]`. -//! impl Index<usize> for TileMap { -//! type Output = Strided; -//! fn index(&self, x: usize) -> &Self::Output { -//! assert!(x < MAP_WIDTH); -//! Strided::ref_cast(&self.storage[x..]) -//! } -//! } -//! -//! impl Index<usize> for Strided { -//! type Output = Tile; -//! fn index(&self, y: usize) -> &Self::Output { -//! &self.0[y * MAP_WIDTH] -//! } -//! } -//! ``` - -#![doc(html_root_url = "https://docs.rs/ref-cast/1.0.24")] -#![no_std] -#![allow( - clippy::extra_unused_type_parameters, - clippy::let_underscore_untyped, - clippy::manual_assert, - clippy::missing_panics_doc, - clippy::missing_safety_doc, - clippy::module_name_repetitions, - clippy::needless_doctest_main, - clippy::needless_pass_by_value -)] - -mod custom; -mod layout; -mod trivial; - -pub use ref_cast_impl::{ref_cast_custom, RefCast, RefCastCustom}; - -/// Safely cast `&T` to `&U` where the struct `U` contains a single field of -/// type `T`. -/// -/// ``` -/// # use ref_cast::RefCast; -/// # -/// // `&String` can be cast to `&U`. -/// #[derive(RefCast)] -/// #[repr(transparent)] -/// struct U(String); -/// -/// // `&T` can be cast to `&V<T>`. -/// #[derive(RefCast)] -/// #[repr(transparent)] -/// struct V<T> { -/// t: T, -/// } -/// ``` -/// -/// See the [crate-level documentation][crate] for usage examples! -pub trait RefCast { - type From: ?Sized; - fn ref_cast(from: &Self::From) -> &Self; - fn ref_cast_mut(from: &mut Self::From) -> &mut Self; -} - -// Not public API. -#[doc(hidden)] -pub mod __private { - #[doc(hidden)] - pub use crate::custom::{ref_cast_custom, CurrentCrate, RefCastCustom}; - #[doc(hidden)] - pub use crate::layout::{assert_layout, Layout, LayoutUnsized}; - #[doc(hidden)] - pub use crate::trivial::assert_trivial; - #[doc(hidden)] - pub use core::mem::transmute; -} |