pub trait Octal {
// Required method
fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>;
}
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§
1.0.0 · Sourcefn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
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 RelayFlags
impl Octal for BigInt
impl Octal for BigUint
impl Octal for CipherCtxFlags
impl Octal for CMSOptions
impl Octal for OcspFlag
impl Octal for Pkcs7Flags
impl Octal for ExtensionContext
impl Octal for ShutdownState
impl Octal for SslMode
impl Octal for SslOptions
impl Octal for SslSessionCacheMode
impl Octal for SslVerifyMode
impl Octal for X509CheckFlags
impl Octal for X509VerifyFlags
impl Octal for Access
impl Octal for AtFlags
impl Octal for BeginFlags
impl Octal for CreateFlags
impl Octal for CreateFlags
impl Octal for DupFlags
impl Octal for EventFlags
impl Octal for EventMask
impl Octal for EventfdFlags
impl Octal for FallocateFlags
impl Octal for FdFlags
impl Octal for FloatingPointEmulationControl
impl Octal for FloatingPointExceptionMode
impl Octal for IFlags
impl Octal for MembarrierQuery
impl Octal for MemfdFlags
impl Octal for Mode
impl Octal for MountFlags
impl Octal for MountPropagationFlags
impl Octal for OFlags
impl Octal for PidfdFlags
impl Octal for PidfdGetfdFlags
impl Octal for PipeFlags
impl Octal for PollFlags
impl Octal for ReadFlags
impl Octal for ReadWriteFlags
impl Octal for RecvFlags
impl Octal for RenameFlags
impl Octal for ResolveFlags
impl Octal for SealFlags
impl Octal for SendFlags
impl Octal for SockaddrXdpFlags
impl Octal for SocketFlags
impl Octal for SpeculationFeatureControl
impl Octal for SpeculationFeatureState
impl Octal for SpliceFlags
impl Octal for StatVfsMountFlags
impl Octal for StatxFlags
impl Octal for TimerfdFlags
impl Octal for TimerfdTimerFlags
impl Octal for UnalignedAccessControl
impl Octal for UnmountFlags
impl Octal for WaitOptions
impl Octal for WaitidOptions
impl Octal for WatchFlags
impl Octal for WatchMask
impl Octal for XattrFlags
impl Octal for XdpDescOptions
impl Octal for XdpOptionsFlags
impl Octal for XdpRingFlags
impl Octal for XdpUmemRegFlags
impl Octal for u1
impl Octal for u2
impl Octal for u3
impl Octal for u4
impl Octal for u5
impl Octal for u6
impl Octal for u7
impl Octal for u24
impl Octal for u40
impl Octal for u48
impl Octal for u56
impl<'a, I> Octal for Format<'a, I>
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<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 Isize<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<O> Octal for Usize<O>where
O: ByteOrder,
impl<T> Octal for &T
impl<T> Octal for &mut T
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> Octal for BoxSensitive<T>where
T: Octal,
impl<T> Octal for FmtBinary<T>
impl<T> Octal for FmtDisplay<T>
impl<T> Octal for FmtList<T>
impl<T> Octal for FmtLowerExp<T>
impl<T> Octal for FmtLowerHex<T>
impl<T> Octal for FmtOctal<T>where
T: Octal,
impl<T> Octal for FmtPointer<T>
impl<T> Octal for FmtUpperExp<T>
impl<T> Octal for FmtUpperHex<T>
impl<T> Octal for Sensitive<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.