在 Rust 中循环遍历整数字节的惯用方法是什么？

Question

我试过这样一段代码循环遍历一个u64:

的字节

let mut message: u64 = 0x1234123412341234;
let msg = &message as *mut u8;

for b in 0..8 {
    // ...some work...
}

不幸的是，Rust 不允许这种类似 C 的索引。

Answer 1

将 u64 转换为数组是安全的 [u8; 8]:

let message_arr: [u8; 8] = unsafe { mem::transmute(message) };
for b in &message_arr {
    println!("{}", b)
}

查看实际效果 on the playground。

Answer 2

虽然 transmute-ing 是可能的（), it is better to use the byteorder crate 以保证字节顺序：

extern crate byteorder;

use byteorder::ByteOrder;

fn main() {
    let message = 0x1234123412341234u64;
    let mut buf = [0; 8];
    byteorder::LittleEndian::write_u64(&mut buf, message);

    for b in &buf {
         // 34, 12, 34, 12, 34, 12, 34, 12, 
         print!("{:X}, ", b);
    }

    println!("");

    byteorder::BigEndian::write_u64(&mut buf, message);

    for b in &buf {
         // 12, 34, 12, 34, 12, 34, 12, 34, 
         print!("{:X}, ", b);
    }
}

(Permalink to the playground)

在 Rust 中循环遍历整数字节的惯用方法是什么？

What is the idiomatic way of looping through the bytes of an integer number in Rust?

arrays

iteration

byte

unsafe

rust