以十六进制表示形式显示u8切片 [英] Show u8 slice in hex representation
问题描述
我需要将& [u8]
转换为十六进制表示。例如 [A9,45,FF,00 ...]
。
特征 std :: fmt :: UpperHex
没有为切片实现(所以我不能使用 std :: fmt :: format
)。 Rust具有 serialize :: hex :: ToHex
特征,它将& [u8]
转换为一个十六进制字符串,但我需要一个带有单独字节的表示。
我可以为& amp; amp; //执行trait
我自己,但我不确定这将是多么规范。什么是最规范的方式来做到这一点? UpperHex
; [u8]
Rust 1.26.0及以上
使用格式化程序可以使用:x?
debug with hexadecimal integers格式化程序:
let data = bhello;
println!({:x?},data);
println!({:X?},data);
[68,65, 6c,6c,6f]
[68,65,6C,6C,6F]
它可以与漂亮修饰符结合使用:
let data = bhello;
println!({:#x?},data);
println!({:#X?},data);
[
0x68,
0x65,
0x6c,
0x6c,
0x6f
]
[
0x68,
0x65,
0x6C,
0x6C,
0x6F
]
如果你需要更多的控制或需要支持老版本的Rust,继续阅读。
Rust 1.0 and up
使用std :: fmt :: Write;
fn main(){
let mut s = String :: new();
for& byte inHello.as_bytes(){
write!(& mut s,{:X},byte).expect(Unable to write);
}
println!({},s);
$ b 这可以通过实现一种格式化特征( fmt :: Debug
, fmt :: Display
, fmt :: LowerHex
, fmt :: UpperHex
等),并且有一个小构造函数:
使用std :: fmt;
struct HexSlice< a>(&'a [u8]);
impl<'a> HexSlice<一> {
新n< T>(数据:&'a T) - > HexSlice<一>
其中T:?Sized + AsRef<>> +'a
{
HexSlice(data.as_ref())
}
}
//你甚至可以选择实现多种特质,比如Lower和UpperHex
impl<'a> fmt :: Display for HexSlice<'a> {
fn fmt(& self,f:& mut fmt :: Formatter) - > fmt :: Result {
用于self.0中的字节{
//决定是否要在这里填充值
write!(f,{:X},byte) ?;
OK(())
}
}
fn main(){
//得到一个`String`
let s = format!({},HexSlice :: new(Hello));
//直接打印
println!({},HexSlice :: new(world));
//与
一起工作HexSlice :: new(Hello); //字符串切片(& str)
HexSlice :: new(bHello); //字节片(& [u8])
HexSlice :: new(&World.to_string()); //引用字符串
HexSlice :: new(& vec![0x00,0x01]); //参考Vec< u8>
}
I need to convert &[u8]
to a hex representation. For example [ A9, 45, FF, 00 ... ]
.
The trait std::fmt::UpperHex
is not implemented for slices (so I can't use std::fmt::format
). Rust has the serialize::hex::ToHex
trait, which converts &[u8]
to a hex String, but I need a representation with separate bytes.
I can implement trait UpperHex
for &[u8]
myself, but I'm not sure how canonical this would be. What is the most canonical way to do this?
解决方案 Rust 1.26.0 and up
The :x?
"debug with hexadecimal integers" formatter can be used:
let data = b"hello";
println!("{:x?}", data);
println!("{:X?}", data);
[68, 65, 6c, 6c, 6f]
[68, 65, 6C, 6C, 6F]
It can be combined with the pretty modifier as well:
let data = b"hello";
println!("{:#x?}", data);
println!("{:#X?}", data);
[
0x68,
0x65,
0x6c,
0x6c,
0x6f
]
[
0x68,
0x65,
0x6C,
0x6C,
0x6F
]
If you need more control or need to support older versions of Rust, keep reading.
Rust 1.0 and up
use std::fmt::Write;
fn main() {
let mut s = String::new();
for &byte in "Hello".as_bytes() {
write!(&mut s, "{:X} ", byte).expect("Unable to write");
}
println!("{}", s);
}
This can be fancied up by implementing one of the formatting traits (fmt::Debug
, fmt::Display
, fmt::LowerHex
, fmt::UpperHex
, etc.) on a struct and having a little constructor:
use std::fmt;
struct HexSlice<'a>(&'a [u8]);
impl<'a> HexSlice<'a> {
fn new<T>(data: &'a T) -> HexSlice<'a>
where T: ?Sized + AsRef<[u8]> + 'a
{
HexSlice(data.as_ref())
}
}
// You can even choose to implement multiple traits, like Lower and UpperHex
impl<'a> fmt::Display for HexSlice<'a> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
for byte in self.0 {
// Decide if you want to pad out the value here
write!(f, "{:X} ", byte)?;
}
Ok(())
}
}
fn main() {
// To get a `String`
let s = format!("{}", HexSlice::new("Hello"));
// Or print it directly
println!("{}", HexSlice::new("world"));
// Works with
HexSlice::new("Hello"); // string slices (&str)
HexSlice::new(b"Hello"); // byte slices (&[u8])
HexSlice::new(&"World".to_string()); // References to String
HexSlice::new(&vec![0x00, 0x01]); // References to Vec<u8>
}
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