rust | 易学教程

Precise memory layout control in Rust?

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问题 As far as I know, the Rust compiler is allowed to pack, reorder, and add padding to each field of a struct. How can I specify the precise memory layout if I need it? In C#, I have the StructLayout attribute, and in C/C++, I could use various compiler extensions. I could verify the memory layout by checking the byte offset of expected value locations. I'd like to write OpenGL code employing custom shaders, which needs precise memory layout. Is there a way to do this without sacrificing

AI 告别炒作，Java 0 增长，2021 技术路在何方？

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【CSDN 编者按】去年，CSDN 整理了 O’Reilly 关于 2020 年技术趋势的解读，其中关于 Python、AI 和云平台的部分预测，在过去一年内都得到了验证。作为一个在线学习网站，O’Reilly 每年都会对开发者需要注意和探索的趋势进行解析。在最新的 2021 年的技术趋势报告中，有哪些新变化，又有哪些值得我们关注的信息，不妨通过本文来一探究竟编译 | 李磊责编 | 张文出品 | CSDN（ID：CSDNnews）受新冠疫情影响， 2020 年在线学习的使用量处于稳定增长，很多公司关闭了办公室，要求员工在家远程办公；线下教育也受到了冲击，线上教育同比增长了 96％，图书的使用量增加了 11％，教育视频的使用量增加了 24％。疫情期间，不少公司急需在线业务的支持以维持生存，包括小型餐馆和农贸市场都增加了网上下单功能。在此之下，每个公司的开发部门成了一个非常重要的部门，为其业务提供各种技术支持。具体在技术、编程语言、工具框架层面，O’Reilly 通过数据分析发现： Python 使用量位列第一，并以 27% 的速度持续增长。多重编程范式、并发编程、动态类型与静态类型的融合、低代码甚至无代码工具的普及将成为未来的趋势。 AI 的内容持续增长，机器学习增长了 14％，人工智能增长了 64％；数据科学增长了 16％，统计数据增长了 47％。 Web

How do I use a paremeter to index an array in rust? [duplicate]

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问题 This question already has answers here : Indexing vector by a 32-bit integer (2 answers) Why are all indexes in Rust of type usize? (1 answer) What is the correct type to use for an array index? (1 answer) Do I have to use a usize to access elements of a vector? (1 answer) How to index vectors with integer types (besides usize), without explicit cast? (2 answers) Closed 1 year ago . I'm trying to create a function that will take a parameter and use it as an index for an array rust will not

Warp filter moving variable out of its environment [duplicate]

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问题 This question already has answers here : Is there another option to share an Arc in multiple closures besides cloning it before each closure? (2 answers) Closed 6 months ago . I am trying to implement a filter that sits in all my routes and extracts a header and matches a possible token to what is stored on my system. I want to implement something like the warp rejection example but I get the error expected a closure that implements the Fn trait, but this closure only implements FnOnce

How to move closures forever

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问题 I'm designing a little struct that runs closures for me and I can set them to stop: pub fn run(&self, f: Box<dyn Fn()>) { let should_continue = self.should_continue.clone(); self.run_thread = Some(std::thread::spawn(move || { while should_continue.load(Ordering::Relaxed) { //f should run fast so `should_continue` is readed frequently f(); } })); } as you can see, I'm passing Fn in a box, which gives me an error about Box not being shareable between threads. Actually, I don't care about fn

how to parse a YAML containing a simple list together with a key-value list (associative array)

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问题 I have the following YAML: build: - step 1 - step 2 - name: step 3 do: something - name: step 4 get: fetch ... - name: step 5 put: upload something And for parsing it I am trying with this #[derive(Debug, Deserialize, PartialEq)] struct Config { build: Option<Vec<Steps>> } #[derive(Debug, Deserialize, PartialEq)] struct Build { #[serde(flatten)] item: String, steps: Steps, } #[derive(Debug, Deserialize, PartialEq)] struct Steps { name: String, r#do: Option<String>, put: Option<String>, get:

how to parse a YAML containing a simple list together with a key-value list (associative array)

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Why do the bytes of a PNG image downloaded with reqwest differ from those downloaded with Python?

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问题 I'm trying to use reqwest library to download a PNG file, but when I download it I see a strange behaviour respect other programming languages like: Python. For instance: let content = reqwest::get("https://www.google.es/images/searchbox/desktop_searchbox_sprites302_hr.png").await?; If I print the result as a bytes array ( println!("{:?}", content.text().await?.as_bytes() ); [ 191, 189, 80, 78, 71, 13, 10, 26, 10, 0, 0, 0, 13, 73, 72, 68, 82, 0, 0, 0, 40, 0, 0, 0, 82, 8, 3, 0, 0, 0, 17, 191,

How do I create a global, mutable singleton?

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问题 What is the best way to create and use a struct with only one instantiation in the system? Yes, this is necessary, it is the OpenGL subsystem, and making multiple copies of this and passing it around everywhere would add confusion, rather than relieve it. The singleton needs to be as efficient as possible. It doesn't seem possible to store an arbitrary object on the static area, as it contains a Vec with a destructor. The second option is to store an (unsafe) pointer on the static area,

What is the syntax for an if-let statement?

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问题 I encountered this snippet in some example code. It works fine, but I got a linter error saying that it should be structured as an if-let statement. match event { glutin::Event::WindowEvent { event, .. } => match event { glutin::WindowEvent::Closed => return glutin::ControlFlow::Break, glutin::WindowEvent::Resized(w, h) => gl_window.resize(w, h), _ => (), }, _ => () } This was my attempt to restructure it: if let _ = glutin::Event::WindowEvent { event, .. } { match event { glutin::WindowEvent