Struct std::num::NonZeroU8 1.28.0[−][src]
#[repr(transparent)]pub struct NonZeroU8(_);Expand description
An integer that is known not to equal zero.
This enables some memory layout optimization.
For example, Option<NonZeroU8> is the same size as u8:
use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroU8>>(), size_of::<u8>());RunImplementations
Creates a non-zero without checking whether the value is non-zero. This results in undefined behaviour if the value is zero.
Safety
The value must not be zero.
Creates a non-zero if the given value is not zero.
Returns the number of leading zeros in the binary representation of self.
On many architectures, this function can perform better than leading_zeros() on the underlying integer type, as special handling of zero can be avoided.
Examples
Basic usage:
let n = std::num::NonZeroU8::new(u8::MAX).unwrap();
assert_eq!(n.leading_zeros(), 0);RunReturns the number of trailing zeros in the binary representation
of self.
On many architectures, this function can perform better than trailing_zeros() on the underlying integer type, as special handling of zero can be avoided.
Examples
Basic usage:
let n = std::num::NonZeroU8::new(0b0101000).unwrap();
assert_eq!(n.trailing_zeros(), 3);RunAdd an unsigned integer to a non-zero value.
Check for overflow and return None on overflow
As a consequence, the result cannot wrap to zero.
Examples
#![feature(nonzero_ops)]
let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;
let max = NonZeroU8::new(u8::MAX)?;
assert_eq!(Some(two), one.checked_add(1));
assert_eq!(None, max.checked_add(1));RunAdd an unsigned integer to a non-zero value,
assuming overflow cannot occur.
Overflow is unchecked, and it is undefined behaviour to overflow
even if the result would wrap to a non-zero value.
The behaviour is undefined as soon as
self + rhs > u8::MAX.
Examples
#![feature(nonzero_ops)]
let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;
assert_eq!(two, unsafe { one.unchecked_add(1) });RunReturns the smallest power of two greater than or equal to n.
Check for overflow and return None
if the next power of two is greater than the type’s maximum value.
As a consequence, the result cannot wrap to zero.
Examples
#![feature(nonzero_ops)]
let two = NonZeroU8::new(2)?;
let three = NonZeroU8::new(3)?;
let four = NonZeroU8::new(4)?;
let max = NonZeroU8::new(u8::MAX)?;
assert_eq!(Some(two), two.checked_next_power_of_two() );
assert_eq!(Some(four), three.checked_next_power_of_two() );
assert_eq!(None, max.checked_next_power_of_two() );RunMultiply two non-zero integers together.
Check for overflow and return None on overflow.
As a consequence, the result cannot wrap to zero.
Examples
#![feature(nonzero_ops)]
let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;
let max = NonZeroU8::new(u8::MAX)?;
assert_eq!(Some(four), two.checked_mul(two));
assert_eq!(None, max.checked_mul(two));RunMultiply two non-zero integers together,
assuming overflow cannot occur.
Overflow is unchecked, and it is undefined behaviour to overflow
even if the result would wrap to a non-zero value.
The behaviour is undefined as soon as
self * rhs > u8::MAX.
Examples
#![feature(nonzero_ops)]
let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;
assert_eq!(four, unsafe { two.unchecked_mul(two) });RunRaise non-zero value to an integer power.
Check for overflow and return None on overflow.
As a consequence, the result cannot wrap to zero.
Examples
#![feature(nonzero_ops)]
let three = NonZeroU8::new(3)?;
let twenty_seven = NonZeroU8::new(27)?;
let half_max = NonZeroU8::new(u8::MAX / 2)?;
assert_eq!(Some(twenty_seven), three.checked_pow(3));
assert_eq!(None, half_max.checked_pow(3));RunRaise non-zero value to an integer power.
Return u8::MAX on overflow.
Examples
#![feature(nonzero_ops)]
let three = NonZeroU8::new(3)?;
let twenty_seven = NonZeroU8::new(27)?;
let max = NonZeroU8::new(u8::MAX)?;
assert_eq!(twenty_seven, three.saturating_pow(3));
assert_eq!(max, max.saturating_pow(3));RunReturns true if and only if self == (1 << k) for some k.
On many architectures, this function can perform better than is_power_of_two()
on the underlying integer type, as special handling of zero can be avoided.
Examples
Basic usage:
#![feature(nonzero_is_power_of_two)]
let eight = std::num::NonZeroU8::new(8).unwrap();
assert!(eight.is_power_of_two());
let ten = std::num::NonZeroU8::new(10).unwrap();
assert!(!ten.is_power_of_two());RunTrait Implementations
Performs the |= operation. Read more
Performs the |= operation. Read more
Converts NonZeroU8 to NonZeroU128 losslessly.
Converts NonZeroU8 to NonZeroU16 losslessly.
Converts NonZeroU8 to NonZeroIsize losslessly.
Converts NonZeroU8 to NonZeroUsize losslessly.
Converts NonZeroU8 to NonZeroI64 losslessly.
Converts NonZeroU8 to NonZeroI32 losslessly.
Converts NonZeroU8 to NonZeroI128 losslessly.
Converts NonZeroU8 to NonZeroU32 losslessly.
Converts NonZeroU8 to NonZeroI16 losslessly.
Converts NonZeroU8 to NonZeroU64 losslessly.
This method returns an ordering between self and other values if one exists. Read more
This method tests less than (for self and other) and is used by the < operator. Read more
This method tests less than or equal to (for self and other) and is used by the <=
operator. Read more
This method tests greater than (for self and other) and is used by the > operator. Read more
pub fn try_from(
value: NonZeroI128
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI128>>::Error>
pub fn try_from(
value: NonZeroI128
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI128>>::Error>
Attempts to convert NonZeroI128 to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroI16
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI16>>::Error>
pub fn try_from(
value: NonZeroI16
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI16>>::Error>
Attempts to convert NonZeroI16 to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroI32
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI32>>::Error>
pub fn try_from(
value: NonZeroI32
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI32>>::Error>
Attempts to convert NonZeroI32 to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroI64
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI64>>::Error>
pub fn try_from(
value: NonZeroI64
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroI64>>::Error>
Attempts to convert NonZeroI64 to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroIsize
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroIsize>>::Error>
pub fn try_from(
value: NonZeroIsize
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroIsize>>::Error>
Attempts to convert NonZeroIsize to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroU128
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU128>>::Error>
pub fn try_from(
value: NonZeroU128
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU128>>::Error>
Attempts to convert NonZeroU128 to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroU16
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU16>>::Error>
pub fn try_from(
value: NonZeroU16
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU16>>::Error>
Attempts to convert NonZeroU16 to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroU32
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU32>>::Error>
pub fn try_from(
value: NonZeroU32
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU32>>::Error>
Attempts to convert NonZeroU32 to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroU64
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU64>>::Error>
pub fn try_from(
value: NonZeroU64
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroU64>>::Error>
Attempts to convert NonZeroU64 to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
pub fn try_from(
value: NonZeroUsize
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroUsize>>::Error>
pub fn try_from(
value: NonZeroUsize
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroUsize>>::Error>
Attempts to convert NonZeroUsize to NonZeroU8.
type Error = TryFromIntError
type Error = TryFromIntError
The type returned in the event of a conversion error.
Auto Trait Implementations
impl RefUnwindSafe for NonZeroU8
impl UnwindSafe for NonZeroU8
Blanket Implementations
Mutably borrows from an owned value. Read more