Trait scale_info::prelude::fmt::UpperHex
1.0.0 · source · pub trait UpperHex {
// Required method
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}
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 x = 42; // 42 is '2A' in hex
assert_eq!(format!("{x:X}"), "2A");
assert_eq!(format!("{x:#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§
Implementors§
impl UpperHex for i8
impl UpperHex for i16
impl UpperHex for i32
impl UpperHex for i64
impl UpperHex for i128
impl UpperHex for isize
impl UpperHex for u8
impl UpperHex for u16
impl UpperHex for u32
impl UpperHex for u64
impl UpperHex for u128
impl UpperHex for usize
impl UpperHex for Bytes
impl UpperHex for BytesMut
impl UpperHex for NonZeroI8
impl UpperHex for NonZeroI16
impl UpperHex for NonZeroI32
impl UpperHex for NonZeroI64
impl UpperHex for NonZeroI128
impl UpperHex for NonZeroIsize
impl UpperHex for NonZeroU8
impl UpperHex for NonZeroU16
impl UpperHex for NonZeroU32
impl UpperHex for NonZeroU64
impl UpperHex for NonZeroU128
impl UpperHex for NonZeroUsize
impl<'a, T, O> UpperHex for Domain<'a, Const, T, O>where O: BitOrder, T: BitStore,
impl<A, O> UpperHex for BitArray<A, O>where O: BitOrder, A: BitViewSized,
impl<T> UpperHex for &Twhere T: UpperHex + ?Sized,
impl<T> UpperHex for &mut Twhere T: UpperHex + ?Sized,
impl<T> UpperHex for FmtBinary<T>where T: Binary + UpperHex,
impl<T> UpperHex for FmtDisplay<T>where T: Display + UpperHex,
impl<T> UpperHex for FmtList<T>where &'a T: for<'a> IntoIterator, <&'a T as IntoIterator>::Item: for<'a> UpperHex,
impl<T> UpperHex for FmtLowerExp<T>where T: LowerExp + UpperHex,
impl<T> UpperHex for FmtLowerHex<T>where T: LowerHex + UpperHex,
impl<T> UpperHex for FmtOctal<T>where T: Octal + UpperHex,
impl<T> UpperHex for FmtPointer<T>where T: Pointer + UpperHex,
impl<T> UpperHex for FmtUpperExp<T>where T: UpperExp + UpperHex,
impl<T> UpperHex for FmtUpperHex<T>where T: UpperHex,
impl<T> UpperHex for Saturating<T>where T: UpperHex,
impl<T> UpperHex for Wrapping<T>where T: UpperHex,
impl<T, O> UpperHex for BitBox<T, O>where O: BitOrder, T: BitStore,
impl<T, O> UpperHex for BitSlice<T, O>where T: BitStore, O: BitOrder,
Bit-Slice Rendering
This implementation prints the contents of a &BitSlice
in one of binary,
octal, or hexadecimal. It is important to note that this does not render the
raw underlying memory! They render the semantically-ordered contents of the
bit-slice as numerals. This distinction matters if you use type parameters that
differ from those presumed by your debugger (which is usually <u8, Msb0>
).
The output separates the T
elements as individual list items, and renders each
element as a base- 2, 8, or 16 numeric string. When walking an element, the bits
traversed by the bit-slice are considered to be stored in
most-significant-bit-first ordering. This means that index [0]
is the high bit
of the left-most digit, and index [n]
is the low bit of the right-most digit,
in a given printed word.
In order to render according to expectations of the Arabic numeral system, an
element being transcribed is chunked into digits from the least-significant end
of its rendered form. This is most noticeable in octal, which will always have a
smaller ceiling on the left-most digit in a printed word, while the right-most
digit in that word is able to use the full 0 ..= 7
numeral range.
Examples
use bitvec::prelude::*;
let data = [
0b000000_10u8,
// digits print LTR
0b10_001_101,
// significance is computed RTL
0b01_000000,
];
let bits = &data.view_bits::<Msb0>()[6 .. 18];
assert_eq!(format!("{:b}", bits), "[10, 10001101, 01]");
assert_eq!(format!("{:o}", bits), "[2, 215, 1]");
assert_eq!(format!("{:X}", bits), "[2, 8D, 1]");
The {:#}
format modifier causes the standard 0b
, 0o
, or 0x
prefix to be
applied to each printed word. The other format specifiers are not interpreted by
this implementation, and apply to the entire rendered text, not to individual
words.