Trait gstd::prelude::fmt::LowerHex

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

x formatting.

The LowerHex trait should format its output as a number in hexadecimal, with a through f in lower 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 LowerHex on a type:

use std::fmt;

struct Length(i32);

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

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

let l = Length(9);

assert_eq!(format!("l as hex is: {l:x}"), "l as hex is: 9");

assert_eq!(format!("l as hex is: {l:#010x}"), "l as hex is: 0x00000009");

Required Methods§

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

Formats the value using the given formatter.

Implementors§

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impl LowerHex for i8

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impl LowerHex for i16

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impl LowerHex for i32

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impl LowerHex for i64

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impl LowerHex for i128

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impl LowerHex for isize

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impl LowerHex for u8

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impl LowerHex for u16

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impl LowerHex for u32

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impl LowerHex for u64

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impl LowerHex for u128

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impl LowerHex for usize

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impl LowerHex for NonZeroI8

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impl LowerHex for NonZeroI16

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impl LowerHex for NonZeroI32

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impl LowerHex for NonZeroI64

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impl LowerHex for NonZeroI128

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impl LowerHex for NonZeroIsize

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impl LowerHex for NonZeroU8

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impl LowerHex for NonZeroU16

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impl LowerHex for NonZeroU32

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impl LowerHex for NonZeroU64

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impl LowerHex for NonZeroU128

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impl LowerHex for NonZeroUsize

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impl LowerHex for Bytes

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impl LowerHex for BytesMut

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impl LowerHex for H128

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impl LowerHex for H160

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impl LowerHex for H256

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impl LowerHex for H384

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impl LowerHex for H512

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impl LowerHex for H768

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impl LowerHex for U128

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impl LowerHex for U256

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impl LowerHex for U512

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impl<'a, T, O> LowerHex for Domain<'a, Const, T, O>
where O: BitOrder, T: BitStore,

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impl<A, O> LowerHex for BitArray<A, O>
where O: BitOrder, A: BitViewSized,

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impl<T> LowerHex for &T
where T: LowerHex + ?Sized,

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impl<T> LowerHex for &mut T
where T: LowerHex + ?Sized,

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impl<T> LowerHex for Saturating<T>
where T: LowerHex,

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impl<T> LowerHex for Wrapping<T>
where T: LowerHex,

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impl<T> LowerHex for FmtBinary<T>
where T: Binary + LowerHex,

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impl<T> LowerHex for FmtDisplay<T>
where T: Display + LowerHex,

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impl<T> LowerHex for FmtList<T>
where &'a T: for<'a> IntoIterator, <&'a T as IntoIterator>::Item: for<'a> LowerHex,

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impl<T> LowerHex for FmtLowerExp<T>
where T: LowerExp + LowerHex,

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impl<T> LowerHex for FmtLowerHex<T>
where T: LowerHex,

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impl<T> LowerHex for FmtOctal<T>
where T: Octal + LowerHex,

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impl<T> LowerHex for FmtPointer<T>
where T: Pointer + LowerHex,

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impl<T> LowerHex for FmtUpperExp<T>
where T: UpperExp + LowerHex,

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impl<T> LowerHex for FmtUpperHex<T>
where T: UpperHex + LowerHex,

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impl<T, O> LowerHex for BitBox<T, O>
where O: BitOrder, T: BitStore,

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impl<T, O> LowerHex 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.

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impl<T, O> LowerHex for BitVec<T, O>
where O: BitOrder, T: BitStore,