Trait frame_support::dispatch::fmt::LowerHex

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

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

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

Formats the value using the given formatter.

Implementors

impl LowerHex for i8

impl LowerHex for i16

impl LowerHex for i32

impl LowerHex for i64

impl LowerHex for i128

impl LowerHex for isize

impl LowerHex for u8

impl LowerHex for u16

impl LowerHex for u32

impl LowerHex for u64

impl LowerHex for u128

impl LowerHex for usize

impl LowerHex for HexDisplay<'_>

impl LowerHex for Mnemonic

impl LowerHex for Seed

impl LowerHex for Bytes

impl LowerHex for BytesMut

impl LowerHex for Limb

impl LowerHex for ed25519::Signature

impl LowerHex for SecretKey

impl LowerHex for Scalar

impl LowerHex for BigInt

impl LowerHex for BigUint

impl LowerHex for H128

impl LowerHex for H160

impl LowerHex for H256

impl LowerHex for H384

impl LowerHex for H512

impl LowerHex for H768

impl LowerHex for U128

impl LowerHex for U256

impl LowerHex for U512

impl LowerHex for rustix::backend::fs::types::Access

impl LowerHex for rustix::backend::fs::types::Access

impl LowerHex for rustix::backend::fs::types::AtFlags

impl LowerHex for rustix::backend::fs::types::AtFlags

impl LowerHex for rustix::backend::fs::types::CloneFlags

impl LowerHex for rustix::backend::fs::types::CloneFlags

impl LowerHex for rustix::backend::fs::types::CopyfileFlags

impl LowerHex for rustix::backend::fs::types::CopyfileFlags

impl LowerHex for rustix::backend::fs::types::FallocateFlags

impl LowerHex for rustix::backend::fs::types::FallocateFlags

impl LowerHex for rustix::backend::fs::types::FdFlags

impl LowerHex for rustix::backend::fs::types::Mode

impl LowerHex for rustix::backend::fs::types::Mode

impl LowerHex for rustix::backend::fs::types::OFlags

impl LowerHex for rustix::backend::fs::types::OFlags

impl LowerHex for rustix::backend::fs::types::StatVfsMountFlags

impl LowerHex for rustix::backend::fs::types::StatVfsMountFlags

impl LowerHex for rustix::backend::io::poll_fd::PollFlags

impl LowerHex for rustix::backend::io::poll_fd::PollFlags

impl LowerHex for rustix::backend::io::types::DupFlags

impl LowerHex for rustix::backend::io::types::DupFlags

impl LowerHex for rustix::backend::io::types::FdFlags

impl LowerHex for MapFlags

impl LowerHex for MprotectFlags

impl LowerHex for MsyncFlags

impl LowerHex for ProtFlags

impl LowerHex for WaitOptions

impl LowerHex for PublicKey

impl LowerHex for XOnlyPublicKey

impl LowerHex for secp256k1::schnorr::Signature

impl LowerHex for Message

impl LowerHex for Capabilities

impl LowerHex for WithdrawReasons

impl LowerHex for NonZeroI8

impl LowerHex for NonZeroI16

impl LowerHex for NonZeroI32

impl LowerHex for NonZeroI64

impl LowerHex for NonZeroI128

impl LowerHex for NonZeroIsize

impl LowerHex for NonZeroU8

impl LowerHex for NonZeroU16

impl LowerHex for NonZeroU32

impl LowerHex for NonZeroU64

impl LowerHex for NonZeroU128

impl LowerHex for NonZeroUsize

impl<'a, I> LowerHex for Format<'a, I>where I: Iterator, <I as Iterator>::Item: LowerHex,

impl<'a, T> LowerHex for StyledValue<'a, T>where T: LowerHex,

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

impl<'s, T> LowerHex for SliceVec<'s, T>where T: LowerHex,

impl<A> LowerHex for TinyVec<A>where A: Array, <A as Array>::Item: LowerHex,

impl<A> LowerHex for ArrayVec<A>where A: Array, <A as Array>::Item: LowerHex,

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

impl<C> LowerHex for ecdsa::Signature<C>where C: PrimeCurve, <<<C as Curve>::UInt as ArrayEncoding>::ByteSize as Add<<<C as Curve>::UInt as ArrayEncoding>::ByteSize>>::Output: ArrayLength<u8>,

impl<C> LowerHex for ScalarCore<C>where C: Curve,

impl<C> LowerHex for NonZeroScalar<C>where C: Curve + ScalarArithmetic,

impl<Size> LowerHex for EncodedPoint<Size>where Size: ModulusSize,

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

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

impl<T> LowerHex for NonZero<T>where T: LowerHex + Zero,

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

impl<T> LowerHex for generic_array::GenericArray<u8, T>where T: ArrayLength<u8> + Add<T>, <T as Add<T>>::Output: ArrayLength<u8>,

impl<T> LowerHex for generic_array::GenericArray<u8, T>where T: ArrayLength<u8> + Add<T>, <T as Add<T>>::Output: ArrayLength<u8>,

impl<T> LowerHex for Ratio<T>where T: LowerHex + Clone + Integer,

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

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

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

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

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

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

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

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

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

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

impl<T> LowerHex for core::num::wrapping::Wrapping<T>where T: LowerHex,

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

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.

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

impl<const LIMBS: usize> LowerHex for UInt<LIMBS>