robert/another-boids-in-rust
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Vendor dependencies for 0.3.0 release

Browse Source
This commit is contained in:
Robert Garrett
2025-09-27 10:29:08 -05:00
parent 0c8d39d483
commit 82ab7f317b
26803 changed files with 16134934 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

1
vendor/presser/.cargo-checksum.json vendored Normal file
View File

@@ -0,0 +1 @@
{"files":{"CHANGELOG.md":"d30e238ea99cf0b7eef9bde74738d59ef9247febe226931c681e54e3e78555ea","CODE_OF_CONDUCT.md":"bdd62923c8e1c5b1d86ff459b7d71a9f1d6279d262c524bae767d7bb4fa65f50","CONTRIBUTING.md":"8580dcd2e6ef627d8666c2e624e00581e3cdf42f10d7d6ab48c65f42ed755ce7","Cargo.toml":"ef362b2fb1b874d6450911fa11fb6f7fa28c033d292cb636e2f9e8d6773ca85f","LICENSE-APACHE":"8173d5c29b4f956d532781d2b86e4e30f83e6b7878dce18c919451d6ba707c90","LICENSE-MIT":"090a294a492ab2f41388252312a65cf2f0e423330b721a68c6665ac64766753b","README.md":"c517d356445491dfc27bd31101753f7c715bfc98b34f2c67f3fde1639f4513b2","release.toml":"35ef9c6d98a56fa088266b04dfc2b4f054e60ce86fc23201227b20d06117b84e","src/lib.rs":"f7942cfcefdd7670785b46eef8265f6d55bec016fdff3762ab9bc66f51553f86"},"package":"e8cf8e6a8aa66ce33f63993ffc4ea4271eb5b0530a9002db8455ea6050c77bfa"}

40
vendor/presser/CHANGELOG.md vendored Normal file
View File

@@ -0,0 +1,40 @@
<!-- markdownlint-disable blanks-around-headings blanks-around-lists no-duplicate-heading -->
# Changelog
All notable changes to this project will be documented in this file.
The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
<!-- next-header -->
## [Unreleased] - ReleaseDate
## [0.3.1] - 2022-10-16
- Small documentation fixes
- Add example to docs
## 0.3.0 - 2022-10-16
- Open source repository
- Support `#[no_std]` via optional `std` feature
- Improve/revamp some documentation
## 0.2.1
- Re-word crate-level safety documentation
## 0.2.0
- Require Rust 1.64
- Added `copy_into_maybe_uninit_slice`
- Added `clone_into_maybe_uninit_slice`
- Remove optional `gpu-allocator` feature and support
## 0.1.1
- Added `maybe_uninit_slice_from_vec` helper function
<!-- next-url -->
[Unreleased]: https://github.com/EmbarkStudios/presser/compare/0.3.1...HEAD
[0.3.1]: https://github.com/EmbarkStudios/presser/compare/0.3.0...0.3.1

76
vendor/presser/CODE_OF_CONDUCT.md vendored Normal file
View File

@@ -0,0 +1,76 @@
# Contributor Covenant Code of Conduct
## Our Pledge
In the interest of fostering an open and welcoming environment, we as
contributors and maintainers pledge to making participation in our project and
our community a harassment-free experience for everyone, regardless of age, body
size, disability, ethnicity, sex characteristics, gender identity and expression,
level of experience, education, socio-economic status, nationality, personal
appearance, race, religion, or sexual identity and orientation.
## Our Standards
Examples of behavior that contributes to creating a positive environment
include:
* Using welcoming and inclusive language
* Being respectful of differing viewpoints and experiences
* Gracefully accepting constructive criticism
* Focusing on what is best for the community
* Showing empathy towards other community members
Examples of unacceptable behavior by participants include:
* The use of sexualized language or imagery and unwelcome sexual attention or
advances
* Trolling, insulting/derogatory comments, and personal or political attacks
* Public or private harassment
* Publishing others' private information, such as a physical or electronic
address, without explicit permission
* Other conduct which could reasonably be considered inappropriate in a
professional setting
## Our Responsibilities
Project maintainers are responsible for clarifying the standards of acceptable
behavior and are expected to take appropriate and fair corrective action in
response to any instances of unacceptable behavior.
Project maintainers have the right and responsibility to remove, edit, or
reject comments, commits, code, wiki edits, issues, and other contributions
that are not aligned to this Code of Conduct, or to ban temporarily or
permanently any contributor for other behaviors that they deem inappropriate,
threatening, offensive, or harmful.
## Scope
This Code of Conduct applies both within project spaces and in public spaces
when an individual is representing the project or its community. Examples of
representing a project or community include using an official project e-mail
address, posting via an official social media account, or acting as an appointed
representative at an online or offline event. Representation of a project may be
further defined and clarified by project maintainers.
## Enforcement
Instances of abusive, harassing, or otherwise unacceptable behavior may be
reported by contacting the project team at opensource@embark-studios.com. All
complaints will be reviewed and investigated and will result in a response that
is deemed necessary and appropriate to the circumstances. The project team is
obligated to maintain confidentiality with regard to the reporter of an incident.
Further details of specific enforcement policies may be posted separately.
Project maintainers who do not follow or enforce the Code of Conduct in good
faith may face temporary or permanent repercussions as determined by other
members of the project's leadership.
## Attribution
This Code of Conduct is adapted from the [Contributor Covenant][homepage], version 1.4,
available at https://www.contributor-covenant.org/version/1/4/code-of-conduct.html
[homepage]: https://www.contributor-covenant.org
For answers to common questions about this code of conduct, see
https://www.contributor-covenant.org/faq

75
vendor/presser/CONTRIBUTING.md vendored Normal file
View File

@@ -0,0 +1,75 @@
# Embark Contributor Guidelines
Welcome! This project is created by the team at [Embark Studios](https://embark.games). We're glad you're interested in contributing! We welcome contributions from people of all backgrounds who are interested in making great software with us.
At Embark, we aspire to empower everyone to create interactive experiences. To do this, we're exploring and pushing the boundaries of new technologies, and sharing our learnings with the open source community.
If you have ideas for collaboration, email us at opensource@embark-studios.com.
We're also hiring full-time engineers to work with us in Stockholm! Check out our current job postings [here](https://www.embark-studios.com/jobs).
## Issues
### Feature Requests
If you have ideas or how to improve our projects, you can suggest features by opening a GitHub issue. Make sure to include details about the feature or change, and describe any uses cases it would enable.
Feature requests will be tagged as `enhancement` and their status will be updated in the comments of the issue.
### Bugs
When reporting a bug or unexpected behavior in a project, make sure your issue describes steps to reproduce the behavior, including the platform you were using, what steps you took, and any error messages.
Reproducible bugs will be tagged as `bug` and their status will be updated in the comments of the issue.
### Wontfix
Issues will be closed and tagged as `wontfix` if we decide that we do not wish to implement it, usually due to being misaligned with the project vision or out of scope. We will comment on the issue with more detailed reasoning.
## Contribution Workflow
### Open Issues
If you're ready to contribute, start by looking at our open issues tagged as [`help wanted`](../../issues?q=is%3Aopen+is%3Aissue+label%3A"help+wanted") or [`good first issue`](../../issues?q=is%3Aopen+is%3Aissue+label%3A"good+first+issue").
You can comment on the issue to let others know you're interested in working on it or to ask questions.
### Making Changes
1. Fork the repository.
2. Create a new feature branch.
3. Make your changes. Ensure that there are no build errors by running the project with your changes locally.
4. Open a pull request with a name and description of what you did. You can read more about working with pull requests on GitHub [here](https://help.github.com/en/articles/creating-a-pull-request-from-a-fork).
5. A maintainer will review your pull request and may ask you to make changes.
## Code Guidelines
### Rust
You can read about our standards and recommendations for working with Rust [here](https://github.com/EmbarkStudios/rust-ecosystem/blob/main/guidelines.md).
### Python
We recommend following [PEP8 conventions](https://www.python.org/dev/peps/pep-0008/) when working with Python modules.
### JavaScript & TypeScript
We use [Prettier](https://prettier.io/) with the default settings to auto-format our JavaScript and TypeScript code.
## Licensing
Unless otherwise specified, all Embark open source projects shall comply with the Rust standard licensing model (MIT + Apache 2.0) and are thereby licensed under a dual license, allowing licensees to choose either MIT OR Apache-2.0 at their option.
## Contributor Terms
Thank you for your interest in Embark Studios’ open source project. By providing a contribution (new or modified code, other input, feedback or suggestions etc.) you agree to these Contributor Terms.
You confirm that each of your contributions has been created by you and that you are the copyright owner. You also confirm that you have the right to provide the contribution to us and that you do it under the Rust dual licence model (MIT + Apache 2.0).
If you want to contribute something that is not your original creation, you may submit it to Embark Studios separately from any contribution, including details of its source and of any license or other restriction (such as related patents, trademarks, agreements etc.)
Please also note that our projects are released with a [Contributor Code of Conduct](CODE_OF_CONDUCT.md) to ensure that they are welcoming places for everyone to contribute. By participating in any Embark Studios open source project, you agree to keep to the Contributor Code of Conduct.

58
vendor/presser/Cargo.toml vendored Normal file
View File

@@ -0,0 +1,58 @@
# THIS FILE IS AUTOMATICALLY GENERATED BY CARGO
#
# When uploading crates to the registry Cargo will automatically
# "normalize" Cargo.toml files for maximal compatibility
# with all versions of Cargo and also rewrite `path` dependencies
# to registry (e.g., crates.io) dependencies.
#
# If you are reading this file be aware that the original Cargo.toml
# will likely look very different (and much more reasonable).
# See Cargo.toml.orig for the original contents.
[package]
edition = "2021"
rust-version = "1.64"
name = "presser"
version = "0.3.1"
authors = [
"Embark <opensource@embark-studios.com>",
"Gray Olson <gray@grayolson.com",
]
publish = true
description = "A crate to help you copy things into raw buffers without invoking spooky action at a distance (undefined behavior)."
homepage = "https://github.com/EmbarkStudios/presser"
documentation = "https://docs.rs/presser"
readme = "README.md"
keywords = [
"copy",
"graphics",
"raw",
"buffer",
"memory",
]
categories = [
"games",
"memory-management",
"graphics",
]
license = "MIT OR Apache-2.0"
repository = "https://github.com/EmbarkStudios/presser"
[package.metadata.docs.rs]
all-features = true
rustdoc-args = [
"--cfg",
"docs_build",
]
[lib]
test = true
doctest = true
[dependencies]
[dev-dependencies]
[features]
default = ["std"]
std = []

201
vendor/presser/LICENSE-APACHE vendored Normal file
View File

@@ -0,0 +1,201 @@
Apache License
Version 2.0, January 2004
http://www.apache.org/licenses/
TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION
1. Definitions.
"License" shall mean the terms and conditions for use, reproduction,
and distribution as defined by Sections 1 through 9 of this document.
"Licensor" shall mean the copyright owner or entity authorized by
the copyright owner that is granting the License.
"Legal Entity" shall mean the union of the acting entity and all
other entities that control, are controlled by, or are under common
control with that entity. For the purposes of this definition,
"control" means (i) the power, direct or indirect, to cause the
direction or management of such entity, whether by contract or
otherwise, or (ii) ownership of fifty percent (50%) or more of the
outstanding shares, or (iii) beneficial ownership of such entity.
"You" (or "Your") shall mean an individual or Legal Entity
exercising permissions granted by this License.
"Source" form shall mean the preferred form for making modifications,
including but not limited to software source code, documentation
source, and configuration files.
"Object" form shall mean any form resulting from mechanical
transformation or translation of a Source form, including but
not limited to compiled object code, generated documentation,
and conversions to other media types.
"Work" shall mean the work of authorship, whether in Source or
Object form, made available under the License, as indicated by a
copyright notice that is included in or attached to the work
(an example is provided in the Appendix below).
"Derivative Works" shall mean any work, whether in Source or Object
form, that is based on (or derived from) the Work and for which the
editorial revisions, annotations, elaborations, or other modifications
represent, as a whole, an original work of authorship. For the purposes
of this License, Derivative Works shall not include works that remain
separable from, or merely link (or bind by name) to the interfaces of,
the Work and Derivative Works thereof.
"Contribution" shall mean any work of authorship, including
the original version of the Work and any modifications or additions
to that Work or Derivative Works thereof, that is intentionally
submitted to Licensor for inclusion in the Work by the copyright owner
or by an individual or Legal Entity authorized to submit on behalf of
the copyright owner. For the purposes of this definition, "submitted"
means any form of electronic, verbal, or written communication sent
to the Licensor or its representatives, including but not limited to
communication on electronic mailing lists, source code control systems,
and issue tracking systems that are managed by, or on behalf of, the
Licensor for the purpose of discussing and improving the Work, but
excluding communication that is conspicuously marked or otherwise
designated in writing by the copyright owner as "Not a Contribution."
"Contributor" shall mean Licensor and any individual or Legal Entity
on behalf of whom a Contribution has been received by Licensor and
subsequently incorporated within the Work.
2. Grant of Copyright License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
copyright license to reproduce, prepare Derivative Works of,
publicly display, publicly perform, sublicense, and distribute the
Work and such Derivative Works in Source or Object form.
3. Grant of Patent License. Subject to the terms and conditions of
this License, each Contributor hereby grants to You a perpetual,
worldwide, non-exclusive, no-charge, royalty-free, irrevocable
(except as stated in this section) patent license to make, have made,
use, offer to sell, sell, import, and otherwise transfer the Work,
where such license applies only to those patent claims licensable
by such Contributor that are necessarily infringed by their
Contribution(s) alone or by combination of their Contribution(s)
with the Work to which such Contribution(s) was submitted. If You
institute patent litigation against any entity (including a
cross-claim or counterclaim in a lawsuit) alleging that the Work
or a Contribution incorporated within the Work constitutes direct
or contributory patent infringement, then any patent licenses
granted to You under this License for that Work shall terminate
as of the date such litigation is filed.
4. Redistribution. You may reproduce and distribute copies of the
Work or Derivative Works thereof in any medium, with or without
modifications, and in Source or Object form, provided that You
meet the following conditions:
(a) You must give any other recipients of the Work or
Derivative Works a copy of this License; and
(b) You must cause any modified files to carry prominent notices
stating that You changed the files; and
(c) You must retain, in the Source form of any Derivative Works
that You distribute, all copyright, patent, trademark, and
attribution notices from the Source form of the Work,
excluding those notices that do not pertain to any part of
the Derivative Works; and
(d) If the Work includes a "NOTICE" text file as part of its
distribution, then any Derivative Works that You distribute must
include a readable copy of the attribution notices contained
within such NOTICE file, excluding those notices that do not
pertain to any part of the Derivative Works, in at least one
of the following places: within a NOTICE text file distributed
as part of the Derivative Works; within the Source form or
documentation, if provided along with the Derivative Works; or,
within a display generated by the Derivative Works, if and
wherever such third-party notices normally appear. The contents
of the NOTICE file are for informational purposes only and
do not modify the License. You may add Your own attribution
notices within Derivative Works that You distribute, alongside
or as an addendum to the NOTICE text from the Work, provided
that such additional attribution notices cannot be construed
as modifying the License.
You may add Your own copyright statement to Your modifications and
may provide additional or different license terms and conditions
for use, reproduction, or distribution of Your modifications, or
for any such Derivative Works as a whole, provided Your use,
reproduction, and distribution of the Work otherwise complies with
the conditions stated in this License.
5. Submission of Contributions. Unless You explicitly state otherwise,
any Contribution intentionally submitted for inclusion in the Work
by You to the Licensor shall be under the terms and conditions of
this License, without any additional terms or conditions.
Notwithstanding the above, nothing herein shall supersede or modify
the terms of any separate license agreement you may have executed
with Licensor regarding such Contributions.
6. Trademarks. This License does not grant permission to use the trade
names, trademarks, service marks, or product names of the Licensor,
except as required for reasonable and customary use in describing the
origin of the Work and reproducing the content of the NOTICE file.
7. Disclaimer of Warranty. Unless required by applicable law or
agreed to in writing, Licensor provides the Work (and each
Contributor provides its Contributions) on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied, including, without limitation, any warranties or conditions
of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A
PARTICULAR PURPOSE. You are solely responsible for determining the
appropriateness of using or redistributing the Work and assume any
risks associated with Your exercise of permissions under this License.
8. Limitation of Liability. In no event and under no legal theory,
whether in tort (including negligence), contract, or otherwise,
unless required by applicable law (such as deliberate and grossly
negligent acts) or agreed to in writing, shall any Contributor be
liable to You for damages, including any direct, indirect, special,
incidental, or consequential damages of any character arising as a
result of this License or out of the use or inability to use the
Work (including but not limited to damages for loss of goodwill,
work stoppage, computer failure or malfunction, or any and all
other commercial damages or losses), even if such Contributor
has been advised of the possibility of such damages.
9. Accepting Warranty or Additional Liability. While redistributing
the Work or Derivative Works thereof, You may choose to offer,
and charge a fee for, acceptance of support, warranty, indemnity,
or other liability obligations and/or rights consistent with this
License. However, in accepting such obligations, You may act only
on Your own behalf and on Your sole responsibility, not on behalf
of any other Contributor, and only if You agree to indemnify,
defend, and hold each Contributor harmless for any liability
incurred by, or claims asserted against, such Contributor by reason
of your accepting any such warranty or additional liability.
END OF TERMS AND CONDITIONS
APPENDIX: How to apply the Apache License to your work.
To apply the Apache License to your work, attach the following
boilerplate notice, with the fields enclosed by brackets "[]"
replaced with your own identifying information. (Don't include
the brackets!) The text should be enclosed in the appropriate
comment syntax for the file format. We also recommend that a
file or class name and description of purpose be included on the
same "printed page" as the copyright notice for easier
identification within third-party archives.
Copyright [yyyy] [name of copyright owner]
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

25
vendor/presser/LICENSE-MIT vendored Normal file
View File

@@ -0,0 +1,25 @@
Copyright (c) 2019 Embark Studios
Permission is hereby granted, free of charge, to any
person obtaining a copy of this software and associated
documentation files (the "Software"), to deal in the
Software without restriction, including without
limitation the rights to use, copy, modify, merge,
publish, distribute, sublicense, and/or sell copies of
the Software, and to permit persons to whom the Software
is furnished to do so, subject to the following
conditions:
The above copyright notice and this permission notice
shall be included in all copies or substantial portions
of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF
ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT
SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR
IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
DEALINGS IN THE SOFTWARE.

130
vendor/presser/README.md vendored Normal file
View File

@@ -0,0 +1,130 @@
<!-- Allow this file to not have a first line heading -->
<!-- markdownlint-disable-file MD041 no-emphasis-as-heading -->
<!-- inline html -->
<!-- markdownlint-disable-file MD033 -->
<div align="center">
# `🗜 presser`
**Utilities to help make copying data around into raw, possibly-uninitialized buffers easier and safer.**
[![Embark](https://img.shields.io/badge/embark-open%20source-blueviolet.svg)](https://embark.dev)
[![Embark](https://img.shields.io/badge/discord-ark-%237289da.svg?logo=discord)](https://discord.gg/dAuKfZS)
[![Crates.io](https://img.shields.io/crates/v/presser.svg)](https://crates.io/crates/presser)
[![Published Docs](https://docs.rs/presser/badge.svg)](https://docs.rs/presser)
[![Git Docs](https://img.shields.io/badge/git%20main%20docs-published-blue?style=plastic)](https://embarkstudios.github.io/presser/presser/index.html)
[![dependency status](https://deps.rs/repo/github/EmbarkStudios/presser/status.svg)](https://deps.rs/repo/github/EmbarkStudios/presser)
</div>
`presser` can help you when copying data into raw buffers. One primary use-case is copying data into
graphics-api-allocated buffers which will then be accessed by the GPU. Common methods for doing this
right now in Rust can often invoke UB in subtle and hard-to-see ways. For example, viewing an allocated
but uninitialized buffer as an `&mut [u8]` **is instantly undefined behavior**\*, and `transmute`ing even a
`T: Copy` type which has *any padding bytes in its layout* as a `&[u8]` to be the source of a copy is
**also instantly undefined behavior**, in both cases because it is *invalid* to create a reference to an invalid
value (and uninitialized memory is an invalid `u8`), *even if* your code never actually accesses that memory.
This immediately makes what seems like the most straightforward way to copy data into buffers unsound 😬
\* *If you're currently thinking to yourself "bah! what's the issue? surely an uninit u8 is just any random bit pattern
and that's fine we don't care," [check out this blog post](https://www.ralfj.de/blog/2019/07/14/uninit.html) by
@RalfJung, one of the people leading the effort to better define Rust's memory and execution model. As is explored
in that blog post, an*uninit*piece of memory is not simply*an arbitrary bit pattern*, it is a wholly separate
state about a piece of memory, outside of its value, which lets the compiler perform optimizations that reorder,
delete, and otherwise change the actual execution flow of your program in ways that cannot be described simply
by "the value could have*some*possible bit pattern". LLVM and Clang are changing themselves to require special
`noundef` attribute to perform many important optimizations that are otherwise unsound. For a concrete example
of the sorts of problems this can cause, [see this issue @scottmcm hit](https://github.com/rust-lang/rust/pull/98919#issuecomment-1186106387).*
## A bad example
```rust
#[derive(Clone, Copy)]
#[repr(C)]
struct MyDataStruct {
a: u8,
b: u32,
}
let my_data = MyDataStruct { a: 0, b: 42 };
// 🚨 MyDataStruct contains 3 padding bytes after `a`, which are
// uninit, therefore getting a slice that includes them is UB!
let my_data_bytes: &[u8] = transmute(&my_data);
// allocate an uninit buffer of some size
let my_buffer: MyBufferType = some_api.alloc_buffer_size(2048);
// 🚨 this is UB for the same reason, these bytes are uninit!
let buffer_as_bytes: &mut [u8] =
slice::from_raw_parts(my_buffer.ptr(), my_buffer.size());
// 🚨 this is UB because not only are both slices invalid,
// this is not ensuring proper alignment!
buffer_as_bytes.copy_from_slice(my_data_bytes);
```
`presser` helps with this by allowing you to view raw allocated memory of some size as a "`Slab`" of memory and then
provides *safe, valid* ways to copy data into that memory:
### A good example
```rust
#[derive(Clone, Copy)]
#[repr(C)]
struct MyDataStruct {
a: u8,
b: u32,
}
let my_data = MyDataStruct { a: 0, b: 42 };
// allocate an uninit buffer of some size
let my_buffer: MyBufferType = some_api.alloc_buffer_size(2048);
// use `RawAllocation` helper to allow access to a presser `Slab`.
// alternatively, you could implement the `Slab` on your buffer type directly if that
// type is owned by your code!
let raw_allocation = presser::RawAllocation::from_raw_parts(my_buffer.ptr(), my_buffer.size());
// here we assert that we have exclusive access to the data in the buffer, and get the actual
// `Slab` to use to copy into.
let slab = unsafe { raw_allocation.borrow_as_slab(); }
// now we may safely copy `my_data` into `my_buffer`, starting at a minimum offset of 0 into the buffer
let copy_record = presser::copy_to_offset(&my_data, &mut slab, 0)?;
// note that due to alignment requirements of `my_data`, the *actual* start of the bytes of
// `my_data` may be placed at a different offset than requested. so, we check the returned
// `CopyRecord` to check the actual start offset of the copied data.
let actual_start_offset = copy_record.copy_start_offset;
```
Note that actually accessing the copied data is a completely separate issue which `presser` does not
(as of now) concern itself with. BE CAREFUL!
See more in [the git `main` docs](https://embarkstudios.github.io/presser/presser/index.html)
or [the released version docs](https://docs.rs/presser).
## Contribution
[![Contributor Covenant](https://img.shields.io/badge/contributor%20covenant-v1.4-ff69b4.svg)](CODE_OF_CONDUCT.md)
We welcome community contributions to this project.
Please read our [Contributor Guide](CONTRIBUTING.md) for more information on how to get started.
Please also read our [Contributor Terms](CONTRIBUTING.md#contributor-terms) before you make any contributions.
Any contribution intentionally submitted for inclusion in an Embark Studios project, shall comply with the Rust standard licensing model (MIT OR Apache 2.0) and therefore be dual licensed as described below, without any additional terms or conditions:
### License
This contribution is dual licensed under EITHER OF
* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or <http://www.apache.org/licenses/LICENSE-2.0>)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or <http://opensource.org/licenses/MIT>)
at your option.
For clarity, "your" refers to Embark or any other licensee/user of the contribution.

11
vendor/presser/release.toml vendored Normal file
View File

@@ -0,0 +1,11 @@
pre-release-commit-message = "Release {{version}}"
dev-version = false
tag-message = "Release {{version}}"
tag-name = "{{version}}"
pre-release-replacements = [
{ file = "CHANGELOG.md", search = "Unreleased", replace = "{{version}}" },
{ file = "CHANGELOG.md", search = "\\.\\.\\.HEAD", replace = "...{{tag_name}}" },
{ file = "CHANGELOG.md", search = "ReleaseDate", replace = "{{date}}" },
{ file = "CHANGELOG.md", search = "<!-- next-header -->", replace = "<!-- next-header -->\n## [Unreleased] - ReleaseDate" },
{ file = "CHANGELOG.md", search = "<!-- next-url -->", replace = "<!-- next-url -->\n[Unreleased]: https://github.com/EmbarkStudios/presser/compare/{{tag_name}}...HEAD" },
]

786
vendor/presser/src/lib.rs vendored Normal file
View File

@@ -0,0 +1,786 @@
//! # `🗜 presser`
//!
//! **Utilities to help make copying data around into raw, possibly-uninitialized buffers
//! easier and safer.**
//!
//! ## Motivation
//!
//! `presser` can help you when copying data into raw buffers. One primary use-case is copying data into
//! graphics-api-allocated buffers which will then be accessed by the GPU. Common methods for doing this
//! right now in Rust can often invoke UB in subtle and hard-to-see ways. For example, viewing an allocated
//! but uninitialized buffer as an `&mut [u8]` **is instantly undefined behavior**\*, and `transmute`ing even a
//! `T: Copy` type which has *any padding bytes in its layout* as a `&[u8]` to be the source of a copy is
//! **also instantly undefined behavior**, in both cases because it is *invalid* to create a reference to an invalid
//! value (and uninitialized memory is an invalid `u8`), *even if* your code never actually accesses that memory.
//! This immediately makes what seems like the most straightforward way to copy data into buffers unsound 😬.
//!
//! `presser` helps with this by allowing you to view raw allocated memory of some size as a "[`Slab`]" of memory and then
//! provides *safe, valid* ways to copy data into that memory. For example, you could implement [`Slab`] for your
//! GPU-allocated buffer type, or use the built-in [`RawAllocation`] workflow described below, then use
//! [`copy_to_offset_with_align`] to copy any `T: Copy` data into that buffer safely for use on the GPU.
//! Of course, if your `T` doesn't have the correct layout the GPU expects, accessing it on the GPU side may still be
//! unsound or at least give an error.
//!
//! \* *If you're currently thinking to yourself "bah! what's the issue? surely an uninit u8 is just any random bit pattern
//! and that's fine we don't care," [check out this blog post](https://www.ralfj.de/blog/2019/07/14/uninit.html) by
//! @RalfJung, one of the people leading the effort to better define Rust's memory and execution model. As is explored
//! in that blog post, an *uninit* piece of memory is not simply *an arbitrary bit pattern*, it is a wholly separate
//! state about a piece of memory, outside of its value, which lets the compiler perform optimizations that reorder,
//! delete, and otherwise change the actual execution flow of your program in ways that cannot be described simply
//! by "the value could have *some* possible bit pattern". LLVM and Clang are changing themselves to require special
//! `noundef` attribute to perform many important optimizations that are otherwise unsound. For a concrete example
//! of the sorts of problems this can cause,
//! [see this issue @scottmcm hit](https://github.com/rust-lang/rust/pull/98919#issuecomment-1186106387).*
//!
//! ## Introduction
//!
//! The main idea is to implement [`Slab`] on raw-buffer-esque-types (see [the `Slab` safety docs][Slab#Safety]),
//! which then enables the use of the other functions within the crate.
//!
//! Depending on your use case, you may be able to implement [`Slab`] directly for your buffer type, or it may
//! be more convenient or necessary to create a wrapping struct that borrows your raw buffer type and in turn
//! implements [`Slab`]. For an example of this, see [`RawAllocation`] and [`BorrowedRawAllocation`], which you
//! may also use directly. The idea is to create a [`RawAllocation`] to your buffer, which you then borrow into
//! a [`BorrowedRawAllocation`] (which implements [`Slab`]) by calling the unsafe function
//! [`RawAllocation::borrow_as_slab`]
//!
//! Once you have a slab, you can use the copy helper functions provided at the crate root, for example,
//! [`copy_to_offset`] and [`copy_to_offset_with_align`].
//!
//! ### Example
//!
//! ```rust,ignore
//! #[derive(Clone, Copy)]
//! #[repr(C)]
//! struct MyDataStruct {
//! a: u8,
//! b: u32,
//! }
//!
//! let my_data = MyDataStruct { a: 0, b: 42 };
//!
//! // allocate an uninit buffer of some size
//! let my_buffer: MyBufferType = some_api.alloc_buffer_size(2048);
//!
//! // use `RawAllocation` helper to allow access to a presser `Slab`.
//! // alternatively, you could implement the `Slab` on `MyByfferType` directly if that
//! // type is owned by your code!
//! let raw_allocation = presser::RawAllocation::from_raw_parts(my_buffer.ptr(), my_buffer.size());
//!
//! // here we assert that we have exclusive access to the data in the buffer, and get the actual
//! // `Slab` to use to copy into.
//! let slab = unsafe { raw_allocation.borrow_as_slab(); }
//!
//! // now we may safely copy `my_data` into `my_buffer`, starting at a minimum offset of 0 into the buffer
//! let copy_record = presser::copy_to_offset(&my_data, &mut slab, 0)?;
//!
//! // note that due to alignment requirements of `my_data`, the *actual* start of the bytes of
//! // `my_data` may be placed at a different offset than requested. so, we check the returned
//! // `CopyRecord` to check the actual start offset of the copied data.
//! let actual_start_offset = copy_record.copy_start_offset;
//! ```
//!
//! ### `#[no_std]`
//!
//! This crate supports `no_std` environments by building without the '`std`' feature. This will limit some
//! of the fuctions the crate can perform.
//!
//! # Safety
//!
//! An important note is that obeying the safety rules specified in the [`Slab`] safety documentation
//! *only* guarantees safety for the *direct results* of the copy operations performed by the
//! helper functions exported at the crate root (and the safe functions on [`Slab`]). **However**,
//! it is ***not*** guaranteed that operations which would previously have been safe to perform
//! using same backing memory that the [`Slab`] you copied into used are still safe.
//!
//! For example, say you have a fully-initialized
//! chunk of bytes (like a `Vec<u8>`), which you view as a [`Slab`], and then (safely) perform a copy
//! operation into using [`copy_to_offset`]. If the `T` you copied into it has any padding bytes in
//! its memory layout, then the memory locations where those padding bytes now exist in the underlying `Vec`'s
//! memory must now be treated as uninitialized. As such, taking any view into that byte vector which
//! relies on those newly-uninit bytes being initialized to be valid (for example, taking a `&[u8]` slice of the `Vec`
//! which includes those bytes, ***even if your code never actually reads from that slice***)
//! is now instant **undefined behavior**.
#![cfg_attr(not(feature = "std"), no_std)]
#![deny(unsafe_op_in_unsafe_fn)]
#![deny(missing_docs)]
// only enables the `doc_auto_cfg` feature when
// the `docs_build` configuration attribute is defined
// this cfg is defined when building on docs.rs (defined thru the project
// Cargo.toml) and when building the docs for publishing on github pages (thru the
// .github/workflows/rustdoc-pages.yml workflow)
#![cfg_attr(docs_build, feature(doc_auto_cfg))]
use core::alloc::Layout;
use core::alloc::LayoutError;
use core::marker::PhantomData;
use core::mem::MaybeUninit;
use core::ptr::NonNull;
/// Represents a contiguous piece of a single allocation with some layout that is used as a
/// data copying destination. May be wholly or partially uninitialized.
///
/// This trait is *basically* equivalent to implementing `Deref`/`DerefMut` with
/// `Target = [MaybeUninit<u8>]` in terms of safety requirements. It is a separate
/// trait for the extra flexibility having a trait we own provides: namely, the ability
/// to implement it on foreign types.
///
/// # Safety
///
/// Implementors of this trait must ensure these guarantees:
///
/// - The memory range represented by `base_ptr` and `size` **may** be wholly or partially uninitialized
/// - `base_ptr` **must** point to a valid, single allocation of at least `size` bytes.
/// - `size` **must not** be greater than `isize::MAX`
///
/// Assume the lifetime of a shared borrow of self is named `'a`:
///
/// - `base_ptr` **must** be [valid][`core::ptr#safety`] for `'a`
/// - `base_ptr` **must *not*** be mutably aliased for `'a`
/// - It is necessary but not sufficient for this requirement that
/// **no outside *mutable* references** may exist to its data, even if they are unused by user code.
///
/// Assume the lifetime of a mutable borrow of self is named `'a`:
///
/// - `base_ptr_mut` **must** be [valid][`core::ptr#safety`] for `'a`
/// - `base_ptr_mut` **must *not*** be aliased at all for `'a`
/// - It is necessary but not sufficient for this requirement that
/// **no outside references** may exist to its data, even if they are unused by user code.
///
/// Also see the [crate-level safety documentation][`crate#safety`].
pub unsafe trait Slab {
/// Get a pointer to the beginning of the allocation represented by `self`.
fn base_ptr(&self) -> *const u8;
/// Get a pointer to the beginning of the allocation represented by `self`.
fn base_ptr_mut(&mut self) -> *mut u8;
/// Get the size of the allocation represented by `self`.
fn size(&self) -> usize;
/// Interpret a portion of `self` as a slice of [`MaybeUninit<u8>`]. This is likely not
/// incredibly useful, you probably want to use [`Slab::as_maybe_uninit_bytes_mut`]
fn as_maybe_uninit_bytes(&self) -> &[MaybeUninit<u8>] {
// SAFETY: Safe so long as top level safety guarantees are held, since
// `MaybeUninit` has same layout as bare type.
unsafe { core::slice::from_raw_parts(self.base_ptr().cast(), self.size()) }
}
/// Interpret a portion of `self` as a mutable slice of [`MaybeUninit<u8>`].
fn as_maybe_uninit_bytes_mut(&mut self) -> &mut [MaybeUninit<u8>] {
// SAFETY: Safe so long as top level safety guarantees are held, since
// `MaybeUninit` has same layout as bare type.
unsafe { core::slice::from_raw_parts_mut(self.base_ptr_mut().cast(), self.size()) }
}
/// Interpret `self` as a byte slice. This assumes that **all bytes**
/// in `self` are initialized.
///
/// # Safety
///
/// Assuming that the safety guarantees for creating `self` were followed,
/// the only extra requirement for this to be safe is that **all memory**
/// within the range of `self` must be **initialized**. If *any bytes* within
/// this range are not initialized, using this function is *instantly **undefined
/// behavior***, even if you *do noting* with the result.
///
/// Also see the [crate-level Safety documentation][`crate#safety`] for more.
unsafe fn assume_initialized_as_bytes(&self) -> &[u8] {
// SAFETY: same requirements as function-level safety assuming the requirements
// for creating `self` are met
unsafe { core::slice::from_raw_parts(self.base_ptr().cast(), self.size()) }
}
/// Interpret `self` as a mutable byte slice. This assumes that **all bytes**
/// in `self` are initialized.
///
/// # Safety
///
/// Assuming that the safety guarantees for creating `self` were followed,
/// the only extra requirement for this to be safe is that **all memory**
/// within the range of `self` must be **initialized**. If *any bytes* within
/// this range are not initialized, using this function is *instantly **undefined
/// behavior***, even if you *do noting* with the result.
///
/// Also see the [crate-level Safety documentation][`crate#safety`] for more.
unsafe fn assume_initialized_as_bytes_mut(&mut self) -> &mut [u8] {
// SAFETY: same requirements as function-level safety assuming the requirements
// for creating `self` are met
unsafe { core::slice::from_raw_parts_mut(self.base_ptr_mut().cast(), self.size()) }
}
/// Interpret a range of `self` as a byte slice. This assumes that **all bytes**
/// within `range` are initialized.
///
/// In the future, this will hopefully not be needed as this operation will be equivalent to
/// something like `self.as_maybe_uninit_bytes_mut()[range].assume_init()`, but the `core`/`std`
/// implementation for this is still being scaffolded.
///
/// # Safety
///
/// Assuming that the safety guarantees for creating `self` were followed,
/// the only extra requirement for this to be safe is that **all memory**
/// within `range` must be **initialized**. If *any bytes* within
/// this range are not initialized, using this function is *instantly **undefined
/// behavior***, even if you *do noting* with the result.
///
/// Also see the [crate-level Safety documentation][`crate#safety`] for more.
unsafe fn assume_range_initialized_as_bytes<R>(&self, range: R) -> &[u8]
where
R: core::slice::SliceIndex<[MaybeUninit<u8>], Output = [MaybeUninit<u8>]>,
{
let maybe_uninit_slice = &self.as_maybe_uninit_bytes()[range];
// SAFETY: same requirements as function-level safety assuming the requirements
// for creating `self` are met since `MaybeUnint<T>` has same layout as `T`
unsafe {
core::slice::from_raw_parts(
maybe_uninit_slice.as_ptr().cast(),
maybe_uninit_slice.len(),
)
}
}
/// Interpret a range of `self` as a mutable byte slice. This assumes that **all bytes**
/// within `range` are initialized.
///
/// In the future, this will hopefully not be needed as this operation will be equivalent to
/// something like `self.as_maybe_uninit_bytes_mut()[range].assume_init()`, but the `core`/`std`
/// implementation for this is still being scaffolded.
///
/// # Safety
///
/// Assuming that the safety guarantees for creating `self` were followed,
/// the only extra requirement for this to be safe is that **all memory**
/// within `range` must be **initialized**. If *any bytes* within
/// this range are not initialized, using this function is *instantly **undefined
/// behavior***, even if you *do noting* with the result.
///
/// Also see the [crate-level Safety documentation][`crate#safety`] for more.
unsafe fn assume_range_initialized_as_bytes_mut<R>(&mut self, range: R) -> &mut [u8]
where
R: core::slice::SliceIndex<[MaybeUninit<u8>], Output = [MaybeUninit<u8>]>,
{
let maybe_uninit_slice = &mut self.as_maybe_uninit_bytes_mut()[range];
// SAFETY: same requirements as function-level safety assuming the requirements
// for creating `self` are met since `MaybeUnint<T>` has same layout as `T`
unsafe {
core::slice::from_raw_parts_mut(
maybe_uninit_slice.as_mut_ptr().cast(),
maybe_uninit_slice.len(),
)
}
}
}
// SAFETY: The captured `[MaybeUninit<u8>]` will all be part of the same allocation object, and borrowck
// will assure that the borrows that occur on `self` on the relevant methods live long enough since they are
// native borrows anyway.
unsafe impl Slab for [MaybeUninit<u8>] {
fn base_ptr(&self) -> *const u8 {
self.as_ptr().cast()
}
fn base_ptr_mut(&mut self) -> *mut u8 {
self.as_mut_ptr().cast()
}
fn size(&self) -> usize {
core::mem::size_of_val(self)
}
}
/// Takes a `Vec` and unsafely resizes it to the given length, returning a mutable slice to `MaybeUninit<T>` for each
/// item in the newly-resized `Vec`.
///
/// # Safety
///
/// You promise that the given `Vec` already has at least `length` capacity. You also promise to either fill all items before dropping
/// the returned slice, or to continue to not violate validity rules for any items that you do not initialize.
#[cfg(feature = "std")]
pub unsafe fn maybe_uninit_slice_from_vec<T>(
vec: &mut Vec<T>,
length: usize,
) -> &mut [MaybeUninit<T>] {
// SAFETY: As long as the function-level safety rules are met, this is valid
unsafe {
#[allow(clippy::uninit_vec)]
vec.set_len(length);
}
// SAFETY: If function-level safety is met, then we are constructing a slice within a single allocation. `MaybeUninit<T>` is valid
// even for uninit memory, and has the same memory layout as `T`.
unsafe { core::slice::from_raw_parts_mut(vec.as_mut_ptr().cast::<MaybeUninit<T>>(), length) }
}
/// Copies the elements from `src` to `dst`, returning a mutable reference to the now initialized contents of `dst`.
///
/// If `T` does not implement `Copy`, use [`clone_into_maybe_uninit_slice`]
///
/// This is similar to [`slice::copy_from_slice`]. This is identical to the implementation of the method
/// `write_to_slice` on [`MaybeUninit`], but that API is as yet unstable.
///
/// # Panics
///
/// This function will panic if the two slices have different lengths.
pub fn copy_into_maybe_uninit_slice<'a, T>(src: &[T], dst: &'a mut [MaybeUninit<T>]) -> &'a mut [T]
where
T: Copy,
{
let uninit_src: &[MaybeUninit<T>] =
// SAFETY: &[T] and &[MaybeUninit<T>] have the same layout
unsafe { &*(src as *const [T] as *const [MaybeUninit<T>]) };
dst.copy_from_slice(uninit_src);
// SAFETY: Valid elements have just been copied into `this` so it is initialized
unsafe { &mut *(dst as *mut [MaybeUninit<T>] as *mut [T]) }
}
/// Clones the elements from `src` to `dst`, returning a mutable reference to the now initialized contents of `dst`.
/// Any already initialized elements will not be dropped.
///
/// If `T` implements `Copy`, use [`copy_into_maybe_uninit_slice`]
///
/// This is similar to [`slice::clone_from_slice`] but does not drop existing elements. This is identical to the implementation of
/// the method `write_to_slice_cloned` on [`MaybeUninit`], but that API is as yet unstable.
///
/// # Panics
///
/// This function will panic if the two slices have different lengths, or if the implementation of `Clone` panics.
///
/// If there is a panic, the already cloned elements will be dropped.
pub fn clone_into_maybe_uninit_slice<'a, T>(src: &[T], dst: &'a mut [MaybeUninit<T>]) -> &'a mut [T]
where
T: Clone,
{
// unlike copy_from_slice this does not call clone_from_slice on the slice
// this is because `MaybeUninit<T: Clone>` does not implement Clone.
struct Guard<'a, T> {
slice: &'a mut [MaybeUninit<T>],
initialized: usize,
}
impl<'a, T> Drop for Guard<'a, T> {
fn drop(&mut self) {
let initialized_part = &mut self.slice[..self.initialized];
// SAFETY: this raw slice will contain only initialized objects
// that's why, it is allowed to drop it.
unsafe {
core::ptr::drop_in_place(
&mut *(initialized_part as *mut [MaybeUninit<T>] as *mut [T]),
);
}
}
}
assert_eq!(
dst.len(),
src.len(),
"destination and source slices have different lengths"
);
// NOTE: We need to explicitly slice them to the same length
// for bounds checking to be elided, and the optimizer will
// generate memcpy for simple cases (for example T = u8).
let len = dst.len();
let src = &src[..len];
// guard is needed b/c panic might happen during a clone
let mut guard = Guard {
slice: dst,
initialized: 0,
};
#[allow(clippy::needless_range_loop)]
for i in 0..len {
guard.slice[i].write(src[i].clone());
guard.initialized += 1;
}
#[allow(clippy::mem_forget)]
core::mem::forget(guard);
// SAFETY: Valid elements have just been written into `this` so it is initialized
unsafe { &mut *(dst as *mut [MaybeUninit<T>] as *mut [T]) }
}
/// Represents a contiguous piece of a single allocation with some layout.
/// May be wholly or partially uninitialized.
///
/// This exists as a convenient way to get access to a type implementing [`Slab`]
/// when dealing with your own raw allocations/buffers if you don't want to or
/// cannot implement [`Slab`] for another native type.
pub struct RawAllocation {
/// A pointer to the base address of the allocation
pub base_ptr: NonNull<u8>,
/// The size of the allocation in bytes
pub size: usize,
}
impl RawAllocation {
/// Create a new [`RawAllocation`] from a pointer and size.
///
/// # Safety
///
/// This function is safe in and of itself, as nothing will be done
/// with the pointer and size upon creation.
pub fn from_raw_parts(base_ptr: NonNull<u8>, size: usize) -> Self {
Self { base_ptr, size }
}
/// Asserts that we are uniquely borrowing the memory range represented by `self` for
/// the duration of the borrow, giving us a [`BorrowedRawAllocation`] which implements [`Slab`].
///
/// # Safety
///
/// Using this method makes some strong guarantees about the contained `base_ptr` and `size`
/// for the duration of the borrow. See the [safety][`Slab#safety`] documentation for the
/// [`Slab`] trait for a list of the guarantees you must make to use this method.
///
/// Also see the [top-level safety documentation][`crate#safety`]
#[allow(clippy::needless_lifetimes)] // Important to be explicit in this case because of unsafety
pub unsafe fn borrow_as_slab<'a>(&'a mut self) -> BorrowedRawAllocation<'a> {
BorrowedRawAllocation {
base_ptr: self.base_ptr,
size: self.size,
phantom: PhantomData,
}
}
}
/// Represents the unique borrow of a contiguous piece of a single allocation with some layout that is used as a
/// data copying destination. May be wholly or partially uninitialized.
///
/// This type can only be obtained through the [`borrow_as_slab`][`RawAllocation::borrow_as_slab`] method on [`RawAllocation`].
pub struct BorrowedRawAllocation<'a> {
base_ptr: NonNull<u8>,
size: usize,
phantom: PhantomData<&'a ()>,
}
// SAFETY: So long as the safety requirements of `borrow_as_slab` are met, this is also safe
// since it's just a basic pass-thru of info.
unsafe impl<'a> Slab for BorrowedRawAllocation<'a> {
fn base_ptr(&self) -> *const u8 {
self.base_ptr.as_ptr() as *const u8
}
fn base_ptr_mut(&mut self) -> *mut u8 {
self.base_ptr.as_ptr()
}
fn size(&self) -> usize {
self.size
}
}
/// Given pointer and offset, returns a new offset aligned to `align`.
///
/// `align` *must* be a power of two and >= 1 or else the result is meaningless.
fn align_offset_up_to(ptr: usize, offset: usize, align: usize) -> Option<usize> {
let offsetted_ptr = ptr.checked_add(offset)?;
let aligned_ptr = offsetted_ptr.checked_add(align - 1)? & !(align - 1);
// don't need to check since we know aligned_ptr is >= ptr at this point
Some(aligned_ptr - ptr)
}
/// Compute and validate offsets for a copy operation with the given parameters.
fn compute_offsets<S: Slab>(
dst: &S,
start_offset: usize,
t_layout: Layout,
min_alignment: usize,
) -> Result<CopyRecord, CopyError> {
let copy_layout = t_layout.align_to(min_alignment.next_power_of_two())?;
let copy_start_offset =
align_offset_up_to(dst.base_ptr() as usize, start_offset, copy_layout.align())
.ok_or(CopyError::InvalidLayout)?;
let copy_end_offset = copy_start_offset
.checked_add(copy_layout.size())
.ok_or(CopyError::InvalidLayout)?;
let copy_end_offset_padded = copy_start_offset
.checked_add(copy_layout.pad_to_align().size())
.ok_or(CopyError::InvalidLayout)?;
// check start is inside slab
// if within slab, we also know that copy_start_offset is <= isize::MAX since slab.size() must be <= isize::MAX
if copy_start_offset > dst.size() {
return Err(CopyError::OffsetOutOfBounds);
}
// check end is inside slab
if copy_end_offset_padded > dst.size() {
return Err(CopyError::OutOfMemory);
}
Ok(CopyRecord {
copy_start_offset,
copy_end_offset,
copy_end_offset_padded,
})
}
/// An error that may occur during a copy operation.
#[derive(Debug)]
pub enum CopyError {
/// Copy would exceed the end of the allocation
OutOfMemory,
/// Requested to copy to an offset outside the bounds of the allocation
OffsetOutOfBounds,
/// Computed invalid layout for copy operation, probably caused by incredibly large size, offset, or min-alignment parameters
InvalidLayout,
}
impl core::fmt::Display for CopyError {
fn fmt(&self, f: &mut core::fmt::Formatter<'_>) -> core::fmt::Result {
write!(f, "{}", match self {
Self::OutOfMemory => "Copy would exceed the end of the allocation",
Self::OffsetOutOfBounds => "Requested copy to a location starting outside the allocation",
Self::InvalidLayout => "Invalid layout, probably caused by incredibly large size, offset, or alignment parameters",
})
}
}
#[cfg(feature = "std")]
impl std::error::Error for CopyError {}
impl From<LayoutError> for CopyError {
fn from(_err: LayoutError) -> Self {
Self::InvalidLayout
}
}
/// Record of the results of a copy operation
#[derive(Debug, Copy, Clone)]
pub struct CopyRecord {
/// The offset from the start of the allocation, in bytes, at which the
/// copy operation began to write data.
///
/// Not necessarily equal to the `start_offset`, since this offset
/// includes necessary padding to assure alignment.
pub copy_start_offset: usize,
/// The offset from the start of the allocation, in bytes, at which the
/// copy operation no longer wrote data.
///
/// This does not include any padding at the end necessary to maintain
/// alignment requirements.
pub copy_end_offset: usize,
/// The offset from the start of the allocation, in bytes, at which the
/// copy operation no longer wrote data, plus any padding necessary to
/// maintain derived alignment requirements.
pub copy_end_offset_padded: usize,
}
/// Copies `src` into the memory represented by `dst` starting at a minimum location
/// of `start_offset` bytes past the start of `dst`.
///
/// - `start_offset` is the offset into the allocation represented by `dst`,
/// in bytes, before which any copied data will *certainly not* be placed. However,
/// the actual beginning of the copied data may not be exactly at `start_offset` if
/// padding bytes are needed to satisfy alignment requirements. The actual beginning
/// of the copied bytes is contained in the returned [`CopyRecord`].
///
/// # Safety
///
/// This function is safe on its own, however it is very possible to do unsafe
/// things if you read the copied data in the wrong way. See the
/// [crate-level Safety documentation][`crate#safety`] for more.
#[inline]
pub fn copy_to_offset<T: Copy, S: Slab>(
src: &T,
dst: &mut S,
start_offset: usize,
) -> Result<CopyRecord, CopyError> {
copy_to_offset_with_align(src, dst, start_offset, 1)
}
/// Copies `src` into the memory represented by `dst` starting at a minimum location
/// of `start_offset` bytes past the start of `dst` and with minimum alignment
/// `min_alignment`.
///
/// - `start_offset` is the offset into the allocation represented by `dst`,
/// in bytes, before which any copied data will *certainly not* be placed. However,
/// the actual beginning of the copied data may not be exactly at `start_offset` if
/// padding bytes are needed to satisfy alignment requirements. The actual beginning
/// of the copied bytes is contained in the returned [`CopyRecord`].
/// - `min_alignment` is the minimum alignment to which the copy will be aligned. The
/// copy may not actually be aligned to `min_alignment` depending on the alignment requirements
/// of `T`.
///
/// # Safety
///
/// This function is safe on its own, however it is very possible to do unsafe
/// things if you read the copied data in the wrong way. See the
/// [crate-level Safety documentation][`crate#safety`] for more.
pub fn copy_to_offset_with_align<T: Copy, S: Slab>(
src: &T,
dst: &mut S,
start_offset: usize,
min_alignment: usize,
) -> Result<CopyRecord, CopyError> {
let t_layout = Layout::new::<T>();
let record = compute_offsets(&*dst, start_offset, t_layout, min_alignment)?;
// SAFETY: if compute_offsets succeeded, this has already been checked to be safe.
let dst_ptr = unsafe { dst.base_ptr_mut().add(record.copy_start_offset) }.cast::<T>();
// SAFETY:
// - src is valid as we have a reference to it
// - dst is valid so long as requirements for `slab` were met, i.e.
// we have unique access to the region described and that it is valid for the duration
// of 'a.
// - areas not overlapping as long as safety requirements of creation of `self` were met,
// i.e. that we have exclusive access to the region of memory described.
// - dst aligned at least to align_of::<T>()
// - checked that copy stays within bounds of our allocation
unsafe {
core::ptr::copy_nonoverlapping(src as *const T, dst_ptr, 1);
}
Ok(record)
}
/// Copies from `slice` into the memory represented by `dst` starting at a minimum location
/// of `start_offset` bytes past the start of `self`.
///
/// - `start_offset` is the offset into the allocation represented by `dst`,
/// in bytes, before which any copied data will *certainly not* be placed. However,
/// the actual beginning of the copied data may not be exactly at `start_offset` if
/// padding bytes are needed to satisfy alignment requirements. The actual beginning
/// of the copied bytes is contained in the returned [`CopyRecord`].
///
/// # Safety
///
/// This function is safe on its own, however it is very possible to do unsafe
/// things if you read the copied data in the wrong way. See the
/// [crate-level Safety documentation][`crate#safety`] for more.
#[inline]
pub fn copy_from_slice_to_offset<T: Copy, S: Slab>(
src: &[T],
dst: &mut S,
start_offset: usize,
) -> Result<CopyRecord, CopyError> {
copy_from_slice_to_offset_with_align(src, dst, start_offset, 1)
}
/// Copies from `slice` into the memory represented by `dst` starting at a minimum location
/// of `start_offset` bytes past the start of `dst`.
///
/// - `start_offset` is the offset into the allocation represented by `dst`,
/// in bytes, before which any copied data will *certainly not* be placed. However,
/// the actual beginning of the copied data may not be exactly at `start_offset` if
/// padding bytes are needed to satisfy alignment requirements. The actual beginning
/// of the copied bytes is contained in the returned [`CopyRecord`].
/// - `min_alignment` is the minimum alignment to which the copy will be aligned. The
/// copy may not actually be aligned to `min_alignment` depending on the alignment requirements
/// of `T` and the underlying allocation.
/// - The whole data of the slice will be copied directly, so, alignment between elements
/// ignores `min_alignment`.
///
/// # Safety
///
/// This function is safe on its own, however it is very possible to do unsafe
/// things if you read the copied data in the wrong way. See the
/// [crate-level Safety documentation][`crate#safety`] for more.
pub fn copy_from_slice_to_offset_with_align<T: Copy, S: Slab>(
src: &[T],
dst: &mut S,
start_offset: usize,
min_alignment: usize,
) -> Result<CopyRecord, CopyError> {
let t_layout = Layout::for_value(src);
let record = compute_offsets(&*dst, start_offset, t_layout, min_alignment)?;
// SAFETY: if compute_offsets succeeded, this has already been checked to be safe.
let dst_ptr = unsafe { dst.base_ptr_mut().add(record.copy_start_offset) }.cast::<T>();
// SAFETY:
// - src is valid as we have a reference to it
// - dst is valid so long as requirements for `slab` were met, i.e.
// we have unique access to the region described and that it is valid for the duration
// of 'a.
// - areas not overlapping as long as safety requirements of creation of `self` were met,
// i.e. that we have exclusive access to the region of memory described.
// - dst aligned at least to align_of::<T>()
// - checked that copy stays within bounds of our allocation
unsafe {
core::ptr::copy_nonoverlapping(src.as_ptr(), dst_ptr, src.len());
}
Ok(record)
}
/// Copies from `src` iterator into the memory represented by `dst` starting at a minimum location
/// of `start_offset` bytes past the start of `dst`.
///
/// Returns a vector of [`CopyRecord`]s, one for each item in the `src` iterator.
///
/// - `start_offset` is the offset into the allocation represented by `dst`,
/// in bytes, before which any copied data will *certainly not* be placed. However,
/// the actual beginning of the copied data may not be exactly at `start_offset` if
/// padding bytes are needed to satisfy alignment requirements. The actual beginning
/// of the copied bytes is contained in the returned [`CopyRecord`]s.
/// - `min_alignment` is the minimum alignment to which the copy will be aligned. The
/// copy may not actually be aligned to `min_alignment` depending on the alignment requirements
/// of `T`.
/// - For this variation, `min_alignment` will also be respected *between* elements yielded by
/// the iterator. To copy inner elements aligned only to `align_of::<T>()`, see
/// [`copy_from_iter_to_offset_with_align_packed`]
///
/// # Safety
///
/// This function is safe on its own, however it is very possible to do unsafe
/// things if you read the copied data in the wrong way. See the
/// [crate-level Safety documentation][`crate#safety`] for more.
#[cfg(feature = "std")]
pub fn copy_from_iter_to_offset_with_align<T: Copy, Iter: Iterator<Item = T>, S: Slab>(
src: Iter,
dst: &mut S,
start_offset: usize,
min_alignment: usize,
) -> Result<Vec<CopyRecord>, CopyError> {
let mut offset = start_offset;
src.map(|item| {
let copy_record = copy_to_offset_with_align(&item, dst, offset, min_alignment)?;
offset = copy_record.copy_end_offset;
Ok(copy_record)
})
.collect::<Result<Vec<_>, _>>()
}
/// Like [`copy_from_iter_to_offset_with_align`] except that
/// alignment between elements yielded by the iterator will ignore `min_alignment`
/// and rather only be aligned to the alignment of `T`.
///
/// Because of this, only one [`CopyRecord`] is returned specifying the record of the
/// entire block of copied data. If the `src` iterator is empty, returns `None`.
pub fn copy_from_iter_to_offset_with_align_packed<T: Copy, Iter: Iterator<Item = T>, S: Slab>(
mut src: Iter,
dst: &mut S,
start_offset: usize,
min_alignment: usize,
) -> Result<Option<CopyRecord>, CopyError> {
let first_record = if let Some(first_item) = src.next() {
copy_to_offset_with_align(&first_item, dst, start_offset, min_alignment)?
} else {
return Ok(None);
};
let mut prev_record = first_record;
for item in src {
let copy_record = copy_to_offset_with_align(&item, dst, prev_record.copy_end_offset, 1)?;
prev_record = copy_record;
}
Ok(Some(CopyRecord {
copy_start_offset: first_record.copy_start_offset,
copy_end_offset: prev_record.copy_end_offset,
copy_end_offset_padded: prev_record.copy_end_offset_padded,
}))
}