core::fmt

Trait UpperHex

1.6.0 · source
pub trait UpperHex {
    // Required method
    fn fmt(&self, f: &mut Formatter<'_>) -> Result;
}
Expand description

X formatting.

The UpperHex trait should format its output as a number in hexadecimal, with A through F in upper case.

For primitive signed integers (i8 to i128, and isize), negative values are formatted as the two’s complement representation.

The alternate flag, #, adds a 0x in front of the output.

For more information on formatters, see the module-level documentation.

§Examples

Basic usage with i32:

let y = 42; // 42 is '2A' in hex

assert_eq!(format!("{y:X}"), "2A");
assert_eq!(format!("{y:#X}"), "0x2A");

assert_eq!(format!("{:X}", -16), "FFFFFFF0");

Implementing UpperHex on a type:

use std::fmt;

struct Length(i32);

impl fmt::UpperHex for Length {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        let val = self.0;

        fmt::UpperHex::fmt(&val, f) // delegate to i32's implementation
    }
}

let l = Length(i32::MAX);

assert_eq!(format!("l as hex is: {l:X}"), "l as hex is: 7FFFFFFF");

assert_eq!(format!("l as hex is: {l:#010X}"), "l as hex is: 0x7FFFFFFF");

Required Methods§

1.6.0 · source

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

§Errors

This function should return Err if, and only if, the provided Formatter returns Err. String formatting is considered an infallible operation; this function only returns a Result because writing to the underlying stream might fail and it must provide a way to propagate the fact that an error has occurred back up the stack.

Implementors§

1.6.0 · source§

impl UpperHex for i8

1.6.0 · source§

impl UpperHex for i16

1.6.0 · source§

impl UpperHex for i32

1.6.0 · source§

impl UpperHex for i64

1.6.0 · source§

impl UpperHex for i128

1.6.0 · source§

impl UpperHex for isize

1.6.0 · source§

impl UpperHex for u8

1.6.0 · source§

impl UpperHex for u16

1.6.0 · source§

impl UpperHex for u32

1.6.0 · source§

impl UpperHex for u64

1.6.0 · source§

impl UpperHex for u128

1.6.0 · source§

impl UpperHex for usize

1.28.0 · source§

impl<T> UpperHex for NonZero<T>

1.74.0 · source§

impl<T: UpperHex> UpperHex for Saturating<T>

1.11.0 · source§

impl<T: UpperHex> UpperHex for Wrapping<T>

1.6.0 · source§

impl<T: ?Sized + UpperHex> UpperHex for &T

1.6.0 · source§

impl<T: ?Sized + UpperHex> UpperHex for &mut T