Trait scale_info::prelude::fmt::Octal
1.0.0 · source · Expand description
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§
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 NonZeroI8
impl Octal for NonZeroI16
impl Octal for NonZeroI32
impl Octal for NonZeroI64
impl Octal for NonZeroI128
impl Octal for NonZeroIsize
impl Octal for NonZeroU8
impl Octal for NonZeroU16
impl Octal for NonZeroU32
impl Octal for NonZeroU64
impl Octal for NonZeroU128
impl Octal for NonZeroUsize
impl<'a, T, O> Octal for Domain<'a, Const, T, O>where
O: BitOrder,
T: BitStore,
impl<A, O> Octal for BitArray<A, O>where
O: BitOrder,
A: BitViewSized,
impl<T> Octal for &Twhere
T: Octal + ?Sized,
impl<T> Octal for &mut Twhere
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 Saturating<T>where
T: Octal,
impl<T> Octal for Wrapping<T>where
T: Octal,
impl<T, O> Octal for BitBox<T, O>where
O: BitOrder,
T: BitStore,
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.