Struct std::num::NonZeroUsize

#[repr(transparent)]
pub struct NonZeroUsize(_);

An integer that is known not to equal zero.

This enables some memory layout optimization. For example, Option<NonZeroUsize> is the same size as usize:

use std::mem::size_of;
assert_eq!(size_of::<Option<core::num::NonZeroUsize>>(), size_of::<usize>());

Implementations

impl NonZeroUsize

pub const unsafe fn new_unchecked(n: usize) -> NonZeroUsize

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.

pub const fn new(n: usize) -> Option<NonZeroUsize>

Creates a non-zero if the given value is not zero.

pub const fn get(self) -> usize

Returns the value as a primitive type.

impl NonZeroUsize

pub const fn leading_zeros(self) -> u32

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::NonZeroUsize::new(usize::MAX).unwrap();

assert_eq!(n.leading_zeros(), 0);

pub const fn trailing_zeros(self) -> u32

Returns 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::NonZeroUsize::new(0b0101000).unwrap();

assert_eq!(n.trailing_zeros(), 3);

impl NonZeroUsize

pub const fn checked_add(self, other: usize) -> Option<NonZeroUsize>

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Add 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 = NonZeroUsize::new(1)?;
let two = NonZeroUsize::new(2)?;
let max = NonZeroUsize::new(usize::MAX)?;

assert_eq!(Some(two), one.checked_add(1));
assert_eq!(None, max.checked_add(1));

pub const fn saturating_add(self, other: usize) -> NonZeroUsize

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Add an unsigned integer to a non-zero value. Return usize::MAX on overflow.

Examples

#![feature(nonzero_ops)]

let one = NonZeroUsize::new(1)?;
let two = NonZeroUsize::new(2)?;
let max = NonZeroUsize::new(usize::MAX)?;

assert_eq!(two, one.saturating_add(1));
assert_eq!(max, max.saturating_add(1));

pub const unsafe fn unchecked_add(self, other: usize) -> NonZeroUsize

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Add 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 > usize::MAX.

Examples

#![feature(nonzero_ops)]

let one = NonZeroUsize::new(1)?;
let two = NonZeroUsize::new(2)?;

assert_eq!(two, unsafe { one.unchecked_add(1) });

pub const fn checked_next_power_of_two(self) -> Option<NonZeroUsize>

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Returns 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 = NonZeroUsize::new(2)?;
let three = NonZeroUsize::new(3)?;
let four = NonZeroUsize::new(4)?;
let max = NonZeroUsize::new(usize::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() );

impl NonZeroUsize

pub const fn checked_mul(self, other: NonZeroUsize) -> Option<NonZeroUsize>

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Multiply 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 = NonZeroUsize::new(2)?;
let four = NonZeroUsize::new(4)?;
let max = NonZeroUsize::new(usize::MAX)?;

assert_eq!(Some(four), two.checked_mul(two));
assert_eq!(None, max.checked_mul(two));

pub const fn saturating_mul(self, other: NonZeroUsize) -> NonZeroUsize

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Multiply two non-zero integers together. Return usize::MAX on overflow.

Examples

#![feature(nonzero_ops)]

let two = NonZeroUsize::new(2)?;
let four = NonZeroUsize::new(4)?;
let max = NonZeroUsize::new(usize::MAX)?;

assert_eq!(four, two.saturating_mul(two));
assert_eq!(max, four.saturating_mul(max));

pub const unsafe fn unchecked_mul(self, other: NonZeroUsize) -> NonZeroUsize

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Multiply 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 > usize::MAX.

Examples

#![feature(nonzero_ops)]

let two = NonZeroUsize::new(2)?;
let four = NonZeroUsize::new(4)?;

assert_eq!(four, unsafe { two.unchecked_mul(two) });

pub const fn checked_pow(self, other: u32) -> Option<NonZeroUsize>

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Raise 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 = NonZeroUsize::new(3)?;
let twenty_seven = NonZeroUsize::new(27)?;
let half_max = NonZeroUsize::new(usize::MAX / 2)?;

assert_eq!(Some(twenty_seven), three.checked_pow(3));
assert_eq!(None, half_max.checked_pow(3));

pub const fn saturating_pow(self, other: u32) -> NonZeroUsize

🔬 This is a nightly-only experimental API. (nonzero_ops #84186)

Raise non-zero value to an integer power. Return usize::MAX on overflow.

Examples

#![feature(nonzero_ops)]

let three = NonZeroUsize::new(3)?;
let twenty_seven = NonZeroUsize::new(27)?;
let max = NonZeroUsize::new(usize::MAX)?;

assert_eq!(twenty_seven, three.saturating_pow(3));
assert_eq!(max, max.saturating_pow(3));

impl NonZeroUsize

pub const fn is_power_of_two(self) -> bool

Returns 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:

let eight = std::num::NonZeroUsize::new(8).unwrap();
assert!(eight.is_power_of_two());
let ten = std::num::NonZeroUsize::new(10).unwrap();
assert!(!ten.is_power_of_two());

Trait Implementations

impl Binary for NonZeroUsize

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

Formats the value using the given formatter.

impl BitOr<NonZeroUsize> for usize

type Output = NonZeroUsize

The resulting type after applying the | operator.

pub fn bitor(self, rhs: NonZeroUsize) -> <usize as BitOr<NonZeroUsize>>::Output

Performs the | operation.

impl BitOr<NonZeroUsize> for NonZeroUsize

type Output = NonZeroUsize

The resulting type after applying the | operator.

pub fn bitor(
    self,
    rhs: NonZeroUsize
) -> <NonZeroUsize as BitOr<NonZeroUsize>>::Output

Performs the | operation.

impl BitOr<usize> for NonZeroUsize

type Output = NonZeroUsize

The resulting type after applying the | operator.

pub fn bitor(self, rhs: usize) -> <NonZeroUsize as BitOr<usize>>::Output

Performs the | operation.

impl BitOrAssign<NonZeroUsize> for NonZeroUsize

pub fn bitor_assign(&mut self, rhs: NonZeroUsize)

Performs the |= operation.

impl BitOrAssign<usize> for NonZeroUsize

pub fn bitor_assign(&mut self, rhs: usize)

Performs the |= operation.

impl Clone for NonZeroUsize

pub fn clone(&self) -> NonZeroUsize

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for NonZeroUsize

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

Formats the value using the given formatter.

impl Display for NonZeroUsize

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

Formats the value using the given formatter.

impl Div<NonZeroUsize> for usize

pub fn div(self, other: NonZeroUsize) -> usize

This operation rounds towards zero, truncating any fractional part of the exact result, and cannot panic.

type Output = usize

The resulting type after applying the / operator.

impl From<NonZeroU16> for NonZeroUsize

pub fn from(small: NonZeroU16) -> NonZeroUsize

Converts NonZeroU16 to NonZeroUsize losslessly.

impl From<NonZeroU8> for NonZeroUsize

pub fn from(small: NonZeroU8) -> NonZeroUsize

Converts NonZeroU8 to NonZeroUsize losslessly.

impl From<NonZeroUsize> for usize

pub fn from(nonzero: NonZeroUsize) -> usize

Converts a NonZeroUsize into an usize

impl FromStr for NonZeroUsize

type Err = ParseIntError

The associated error which can be returned from parsing.

pub fn from_str(
    src: &str
) -> Result<NonZeroUsize, <NonZeroUsize as FromStr>::Err>

Parses a string s to return a value of this type.

impl Hash for NonZeroUsize

pub fn hash<__H>(&self, state: &mut __H) where
    __H: Hasher, 

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H) where
    H: Hasher, 

Feeds a slice of this type into the given Hasher.

impl LowerHex for NonZeroUsize

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

Formats the value using the given formatter.

impl Octal for NonZeroUsize

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

Formats the value using the given formatter.

impl Ord for NonZeroUsize

pub fn cmp(&self, other: &NonZeroUsize) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

Restrict a value to a certain interval.

impl PartialEq<NonZeroUsize> for NonZeroUsize

pub fn eq(&self, other: &NonZeroUsize) -> bool

This method tests for self and other values to be equal, and is used by ==.

pub fn ne(&self, other: &NonZeroUsize) -> bool

This method tests for !=.

impl PartialOrd<NonZeroUsize> for NonZeroUsize

pub fn partial_cmp(&self, other: &NonZeroUsize) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator.

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator.

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator.

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator.

impl Rem<NonZeroUsize> for usize

pub fn rem(self, other: NonZeroUsize) -> usize

This operation satisfies n % d == n - (n / d) * d, and cannot panic.

type Output = usize

The resulting type after applying the % operator.

impl TryFrom<NonZeroI128> for NonZeroUsize

pub fn try_from(
    value: NonZeroI128
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI128>>::Error>

Attempts to convert NonZeroI128 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroI16> for NonZeroUsize

pub fn try_from(
    value: NonZeroI16
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI16>>::Error>

Attempts to convert NonZeroI16 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroI32> for NonZeroUsize

pub fn try_from(
    value: NonZeroI32
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI32>>::Error>

Attempts to convert NonZeroI32 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroI64> for NonZeroUsize

pub fn try_from(
    value: NonZeroI64
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI64>>::Error>

Attempts to convert NonZeroI64 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroI8> for NonZeroUsize

pub fn try_from(
    value: NonZeroI8
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroI8>>::Error>

Attempts to convert NonZeroI8 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroUsize

pub fn try_from(
    value: NonZeroIsize
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroIsize>>::Error>

Attempts to convert NonZeroIsize to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroU128> for NonZeroUsize

pub fn try_from(
    value: NonZeroU128
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroU128>>::Error>

Attempts to convert NonZeroU128 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroU32> for NonZeroUsize

pub fn try_from(
    value: NonZeroU32
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroU32>>::Error>

Attempts to convert NonZeroU32 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroU64> for NonZeroUsize

pub fn try_from(
    value: NonZeroU64
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<NonZeroU64>>::Error>

Attempts to convert NonZeroU64 to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroU32

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroU32, <NonZeroU32 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU32.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroI64

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroI64, <NonZeroI64 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI64.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroU8

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroU8, <NonZeroU8 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU8.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroI32

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroI32, <NonZeroI32 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI32.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroI8

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroI8, <NonZeroI8 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI8.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroIsize

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroIsize, <NonZeroIsize as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroU64

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroU64, <NonZeroU64 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU64.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroI128

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroI128, <NonZeroI128 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI128.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroI16

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroI16, <NonZeroI16 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroI16.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroU128

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroU128, <NonZeroU128 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU128.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroU16

pub fn try_from(
    value: NonZeroUsize
) -> Result<NonZeroU16, <NonZeroU16 as TryFrom<NonZeroUsize>>::Error>

Attempts to convert NonZeroUsize to NonZeroU16.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<usize> for NonZeroUsize

pub fn try_from(
    value: usize
) -> Result<NonZeroUsize, <NonZeroUsize as TryFrom<usize>>::Error>

Attempts to convert usize to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl UpperHex for NonZeroUsize

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

Formats the value using the given formatter.

impl Copy for NonZeroUsize

impl Eq for NonZeroUsize

impl StructuralEq for NonZeroUsize

impl StructuralPartialEq for NonZeroUsize