Rust 中的冒号运算符与 C 中的冒号运算符有什么相似之处? [英] What is similar in Rust to the colon operator in C?

问题描述

如何在 Rust 中表示这种代码?

How to represent this kind of code in Rust?

uint8_t  pmport:4;  
uint8_t  rsv0:3;        
uint8_t  c:1;       

我想将这 3 个值打包成一个 u8.如何在 Rust 中实现这一点?

I want to pack these 3 values into a single u8. How can this be achieved in Rust?

推荐答案

Rust 没有像 C 那样在语言中内置位域.但是，您可以使用像 bitfield 这样的 crate 来实现相同的目的.bitfield 宏允许您定义每个位域的类型、大小和访问器方法.

Rust does not have bit fields built into the language like C does. However, you can use a crate like bitfield to achieve the same thing. The bitfield macro lets you define the types, size and accessor methods for each bit field.

#[macro_use] extern crate bitfield;

bitfield! {
    struct Example(u8);
    u8;
    get_pmport, set_pmport: 3, 0; // bits 0-3
    get_rsv0, set_rsv0: 6, 4;     // bits 4-6
    get_c, set_c: 7, 7;           // bit 7
}

fn main() {
    println!("size of Example: {}", ::std::mem::size_of::<Example>());
    let mut e = Example(0);
    println!("pmport: {}, rsv0: {}, c: {}", e.get_pmport(), e.get_rsv0(), e.get_c());
    e.set_pmport(5);
    println!("pmport: {}, rsv0: {}, c: {}", e.get_pmport(), e.get_rsv0(), e.get_c());
    e.set_rsv0(3);
    println!("pmport: {}, rsv0: {}, c: {}", e.get_pmport(), e.get_rsv0(), e.get_c());
    e.set_c(1);
    println!("pmport: {}, rsv0: {}, c: {}", e.get_pmport(), e.get_rsv0(), e.get_c());
    e.set_rsv0(0);
    println!("pmport: {}, rsv0: {}, c: {}", e.get_pmport(), e.get_rsv0(), e.get_c());
}

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