# Struct core::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>());
```

Run## Implementations

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());
```

Run## Trait Implementations

Performs the `|=`

operation. Read more

Performs the `|=`

operation. Read more

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

Attempts to convert `NonZeroI128`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroI16`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroI32`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroI64`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroIsize`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroU128`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroU16`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroU32`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroU64`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Attempts to convert `NonZeroUsize`

to `NonZeroU8`

.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.