Trait frame_support::dispatch::fmt::Octal

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

o formatting.

The Octal trait should format its output as a number in base-8.

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

The alternate flag, #, adds a 0o 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 '52' in octal

assert_eq!(format!("{x:o}"), "52");
assert_eq!(format!("{x:#o}"), "0o52");

assert_eq!(format!("{:o}", -16), "37777777760");

Implementing Octal on a type:

use std::fmt;

struct Length(i32);

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

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

let l = Length(9);

assert_eq!(format!("l as octal is: {l:o}"), "l as octal is: 11");

assert_eq!(format!("l as octal is: {l:#06o}"), "l as octal is: 0o0011");

Required Methods

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

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

impl Octal for i8

impl Octal for i16

impl Octal for i32

impl Octal for i64

impl Octal for i128

impl Octal for isize

impl Octal for u8

impl Octal for u16

impl Octal for u32

impl Octal for u64

impl Octal for u128

impl Octal for usize

impl Octal for FrameFlags

impl Octal for CreateFlags

impl Octal for ReadFlags

impl Octal for WatchFlags

impl Octal for Access

impl Octal for AtFlags

impl Octal for FallocateFlags

impl Octal for MemfdFlags

impl Octal for Mode

impl Octal for OFlags

impl Octal for RenameFlags

impl Octal for ResolveFlags

impl Octal for SealFlags

impl Octal for StatVfsMountFlags

impl Octal for StatxFlags

impl Octal for DupFlags

impl Octal for FdFlags

impl Octal for ReadWriteFlags

impl Octal for MapFlags

impl Octal for MlockAllFlags

impl Octal for MlockFlags

impl Octal for MprotectFlags

impl Octal for MremapFlags

impl Octal for MsyncFlags

impl Octal for ProtFlags

impl Octal for UserfaultfdFlags

impl Octal for MountFlags

impl Octal for MountPropagationFlags

impl Octal for UnmountFlags

impl Octal for Flags

impl Octal for TimerfdFlags

impl Octal for TimerfdTimerFlags

impl Octal for IFlags

impl Octal for XattrFlags

impl Octal for MembarrierQuery

impl Octal for PidfdFlags

impl Octal for PidfdGetfdFlags

impl Octal for FloatingPointEmulationControl

impl Octal for FloatingPointExceptionMode

impl Octal for SpeculationFeatureControl

impl Octal for SpeculationFeatureState

impl Octal for UnalignedAccessControl

impl Octal for WaitOptions

impl Octal for WaitidOptions

impl Octal for CapabilityFlags

impl Octal for CapabilitiesSecureBits

impl Octal for TaggedAddressMode

impl Octal for ThreadNameSpaceType

impl Octal for UnshareFlags

impl Octal for Capabilities

impl Octal for WithdrawReasons

impl<'a, I> Octal for Format<'a, I>

where I: Iterator, <I as Iterator>::Item: Octal,

impl<'a, T> Octal for StyledValue<'a, T>

where T: Octal,

impl<'a, T, O> Octal for Domain<'a, Const, T, O>

where O: BitOrder, T: BitStore,

impl<'s, T> Octal for SliceVec<'s, T>

where T: Octal,

impl<A> Octal for TinyVec<A>

where A: Array, <A as Array>::Item: Octal,

impl<A> Octal for ArrayVec<A>

where A: Array, <A as Array>::Item: Octal,

impl<A, O> Octal for BitArray<A, O>

where O: BitOrder, A: BitViewSized,

impl<O> Octal for I16<O>

where O: ByteOrder,

impl<O> Octal for I32<O>

where O: ByteOrder,

impl<O> Octal for I64<O>

where O: ByteOrder,

impl<O> Octal for I128<O>

where O: ByteOrder,

impl<O> Octal for U16<O>

where O: ByteOrder,

impl<O> Octal for U32<O>

where O: ByteOrder,

impl<O> Octal for U64<O>

where O: ByteOrder,

impl<O> Octal for U128<O>

where O: ByteOrder,

impl<T> Octal for &T

where T: Octal + ?Sized,

impl<T> Octal for &mut T

where T: Octal + ?Sized,

impl<T> Octal for FmtBinary<T>

where T: Binary + Octal,

impl<T> Octal for FmtDisplay<T>

where T: Display + Octal,

impl<T> Octal for FmtList<T>

where &'a T: for<'a> IntoIterator, <&'a T as IntoIterator>::Item: for<'a> Octal,

impl<T> Octal for FmtLowerExp<T>

where T: LowerExp + Octal,

impl<T> Octal for FmtLowerHex<T>

where T: LowerHex + Octal,

impl<T> Octal for FmtOctal<T>

where T: Octal,

impl<T> Octal for FmtPointer<T>

where T: Pointer + Octal,

impl<T> Octal for FmtUpperExp<T>

where T: UpperExp + Octal,

impl<T> Octal for FmtUpperHex<T>

where T: UpperHex + Octal,

impl<T> Octal for NonZero<T>

where T: ZeroablePrimitive + Octal,

impl<T> Octal for Saturating<T>

where T: Octal,

impl<T> Octal for Wrapping<T>

where T: Octal,

impl<T, O> Octal 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.