主页 / user-22747722

Richard Neumann's questions

Martin Hope
Richard Neumann
Asked: 2023-10-19 21:17:40 +0800 CST
  • 5

我想实现一个扩展特征std::io::Read来读取任意数字。但是我无法找到如何使用num_traits板条箱获取任意数字的字节数（或者其他板条箱可能提供此信息）：

use num_traits::FromBytes;
use std::io::{Read, Result};

pub trait ReadNums: Read {
    fn read_num_be<N>(&mut self) -> Result<N>
    where
        N: FromBytes,
    {
        let mut buffer = [0; N::WHAT_HERE];
        self.read_exact(&mut buffer)?;
        Ok(N::from_be_bytes(&buffer))
    }
}

impl<T> ReadNums for T where T: Read {}

[package]
name = "numtrait_test"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
num-traits = "0.2.17"

我不知道该放什么N::WHAT_HERE。N我需要此处以字节为单位的相应大小作为const. 对于我的用例来说，使用夜间功能是不可能的。

rust