Struct core::num::NonZeroIsize

pub struct NonZeroIsize(/* private fields */);

An integer that is known not to equal zero.

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

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

Layout

NonZeroIsize is guaranteed to have the same layout and bit validity as isize with the exception that 0 is not a valid instance. Option<NonZeroIsize> is guaranteed to be compatible with isize, including in FFI.

Thanks to the null pointer optimization, NonZeroIsize and Option<NonZeroIsize> are guaranteed to have the same size and alignment:

use std::num::NonZeroIsize;

assert_eq!(size_of::<NonZeroIsize>(), size_of::<Option<NonZeroIsize>>());
assert_eq!(align_of::<NonZeroIsize>(), align_of::<Option<NonZeroIsize>>());

Implementations

impl NonZeroIsize

pub const unsafe fn new_unchecked(n: isize) -> Self

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: isize) -> Option<Self>

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

pub unsafe fn from_mut_unchecked(n: &mut isize) -> &mut Self

🔬This is a nightly-only experimental API. (nonzero_from_mut #106290)

Converts a primitive mutable reference to a non-zero mutable reference without checking whether the referenced value is non-zero. This results in undefined behavior if *n is zero.

Safety

The referenced value must not be currently zero.

pub fn from_mut(n: &mut isize) -> Option<&mut Self>

🔬This is a nightly-only experimental API. (nonzero_from_mut #106290)

Converts a primitive mutable reference to a non-zero mutable reference if the referenced integer is not zero.

pub const fn get(self) -> isize

Returns the value as a primitive type.

pub const BITS: u32 = 64u32

The size of this non-zero integer type in bits.

This value is equal to isize::BITS.

Examples

assert_eq!(NonZeroIsize::BITS, isize::BITS);

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::NonZeroIsize::new(-1isize).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::NonZeroIsize::new(0b0101000).unwrap();

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

pub fn count_ones(self) -> NonZeroU32

🔬This is a nightly-only experimental API. (non_zero_count_ones #120287)

Returns the number of ones in the binary representation of self.

Examples

Basic usage:

#![feature(non_zero_count_ones)]

let one = num::NonZeroU32::new(1)?;
let three = num::NonZeroU32::new(3)?;
let a = NonZeroIsize::new(0b100_0000)?;
let b = NonZeroIsize::new(0b100_0011)?;

assert_eq!(a.count_ones(), one);
assert_eq!(b.count_ones(), three);

pub const MIN: Self = _

The smallest value that can be represented by this non-zero integer type, equal to isize::MIN.

Note: While most integer types are defined for every whole number between MIN and MAX, signed non-zero integers are a special case. They have a “gap” at 0.

Examples

assert_eq!(NonZeroIsize::MIN.get(), isize::MIN);

pub const MAX: Self = _

The largest value that can be represented by this non-zero integer type, equal to isize::MAX.

Note: While most integer types are defined for every whole number between MIN and MAX, signed non-zero integers are a special case. They have a “gap” at 0.

Examples

assert_eq!(NonZeroIsize::MAX.get(), isize::MAX);

pub const fn abs(self) -> Self

Computes the absolute value of self. See isize::abs for documentation on overflow behaviour.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;

assert_eq!(pos, pos.abs());
assert_eq!(pos, neg.abs());

pub const fn checked_abs(self) -> Option<Self>

Checked absolute value. Checks for overflow and returns None if self == NonZeroIsize::MIN. The result cannot be zero.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(Some(pos), neg.checked_abs());
assert_eq!(None, min.checked_abs());

pub const fn overflowing_abs(self) -> (Self, bool)

Computes the absolute value of self, with overflow information, see isize::overflowing_abs.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!((pos, false), pos.overflowing_abs());
assert_eq!((pos, false), neg.overflowing_abs());
assert_eq!((min, true), min.overflowing_abs());

pub const fn saturating_abs(self) -> Self

Saturating absolute value, see isize::saturating_abs.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;
let min_plus = NonZeroIsize::new(isize::MIN + 1)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(pos, pos.saturating_abs());
assert_eq!(pos, neg.saturating_abs());
assert_eq!(max, min.saturating_abs());
assert_eq!(max, min_plus.saturating_abs());

pub const fn wrapping_abs(self) -> Self

Wrapping absolute value, see isize::wrapping_abs.

Example

let pos = NonZeroIsize::new(1)?;
let neg = NonZeroIsize::new(-1)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(pos, pos.wrapping_abs());
assert_eq!(pos, neg.wrapping_abs());
assert_eq!(min, min.wrapping_abs());
assert_eq!(max, (-max).wrapping_abs());

pub const fn unsigned_abs(self) -> NonZeroUsize

Computes the absolute value of self without any wrapping or panicking.

Example

let u_pos = NonZeroUsize::new(1)?;
let i_pos = NonZeroIsize::new(1)?;
let i_neg = NonZeroIsize::new(-1)?;
let i_min = NonZeroIsize::new(isize::MIN)?;
let u_max = NonZeroUsize::new(usize::MAX / 2 + 1)?;

assert_eq!(u_pos, i_pos.unsigned_abs());
assert_eq!(u_pos, i_neg.unsigned_abs());
assert_eq!(u_max, i_min.unsigned_abs());

pub const fn is_positive(self) -> bool

Returns true if self is positive and false if the number is negative.

Example

let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;

assert!(pos_five.is_positive());
assert!(!neg_five.is_positive());

pub const fn is_negative(self) -> bool

Returns true if self is negative and false if the number is positive.

Example

let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;

assert!(neg_five.is_negative());
assert!(!pos_five.is_negative());

pub const fn checked_neg(self) -> Option<Self>

Checked negation. Computes -self, returning None if self == NonZeroIsize::MIN.

Example

let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(pos_five.checked_neg(), Some(neg_five));
assert_eq!(min.checked_neg(), None);

pub const fn overflowing_neg(self) -> (Self, bool)

Negates self, overflowing if this is equal to the minimum value.

See isize::overflowing_neg for documentation on overflow behaviour.

Example

let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(pos_five.overflowing_neg(), (neg_five, false));
assert_eq!(min.overflowing_neg(), (min, true));

pub const fn saturating_neg(self) -> Self

Saturating negation. Computes -self, returning NonZeroIsize::MAX if self == NonZeroIsize::MIN instead of overflowing.

Example

let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;
let min = NonZeroIsize::new(isize::MIN)?;
let min_plus_one = NonZeroIsize::new(isize::MIN + 1)?;
let max = NonZeroIsize::new(isize::MAX)?;

assert_eq!(pos_five.saturating_neg(), neg_five);
assert_eq!(min.saturating_neg(), max);
assert_eq!(max.saturating_neg(), min_plus_one);

pub const fn wrapping_neg(self) -> Self

Wrapping (modular) negation. Computes -self, wrapping around at the boundary of the type.

See isize::wrapping_neg for documentation on overflow behaviour.

Example

let pos_five = NonZeroIsize::new(5)?;
let neg_five = NonZeroIsize::new(-5)?;
let min = NonZeroIsize::new(isize::MIN)?;

assert_eq!(pos_five.wrapping_neg(), neg_five);
assert_eq!(min.wrapping_neg(), min);

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

Multiplies two non-zero integers together. Checks for overflow and returns None on overflow. As a consequence, the result cannot wrap to zero.

Examples

let two = NonZeroIsize::new(2)?;
let four = NonZeroIsize::new(4)?;
let max = NonZeroIsize::new(isize::MAX)?;

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

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

Multiplies two non-zero integers together. Return NonZeroIsize::MAX on overflow.

Examples

let two = NonZeroIsize::new(2)?;
let four = NonZeroIsize::new(4)?;
let max = NonZeroIsize::new(isize::MAX)?;

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

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

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

Multiplies 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 > isize::MAX, or self * rhs < isize::MIN.

Examples

#![feature(nonzero_ops)]

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

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

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

Raises non-zero value to an integer power. Checks for overflow and returns None on overflow. As a consequence, the result cannot wrap to zero.

Examples

let three = NonZeroIsize::new(3)?;
let twenty_seven = NonZeroIsize::new(27)?;
let half_max = NonZeroIsize::new(isize::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) -> Self

Raise non-zero value to an integer power. Return NonZeroIsize::MIN or NonZeroIsize::MAX on overflow.

Examples

let three = NonZeroIsize::new(3)?;
let twenty_seven = NonZeroIsize::new(27)?;
let max = NonZeroIsize::new(isize::MAX)?;

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

Trait Implementations

impl Binary for NonZeroIsize

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

Formats the value using the given formatter.

impl BitOr<NonZeroIsize> for isize

type Output = NonZeroIsize

The resulting type after applying the | operator.

fn bitor(self, rhs: NonZeroIsize) -> Self::Output

Performs the | operation.

impl BitOr<isize> for NonZeroIsize

type Output = NonZeroIsize

The resulting type after applying the | operator.

fn bitor(self, rhs: isize) -> Self::Output

Performs the | operation.

impl BitOr for NonZeroIsize

type Output = NonZeroIsize

The resulting type after applying the | operator.

fn bitor(self, rhs: Self) -> Self::Output

Performs the | operation.

impl BitOrAssign<isize> for NonZeroIsize

fn bitor_assign(&mut self, rhs: isize)

Performs the |= operation.

impl BitOrAssign for NonZeroIsize

fn bitor_assign(&mut self, rhs: Self)

Performs the |= operation.

impl Clone for NonZeroIsize

fn clone(&self) -> Self

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for NonZeroIsize

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

Formats the value using the given formatter.

impl Display for NonZeroIsize

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

Formats the value using the given formatter.

impl From<NonZeroI16> for NonZeroIsize

fn from(small: NonZeroI16) -> Self

Converts NonZeroI16 to NonZeroIsize losslessly.

impl From<NonZeroI8> for NonZeroIsize

fn from(small: NonZeroI8) -> Self

Converts NonZeroI8 to NonZeroIsize losslessly.

impl From<NonZeroIsize> for isize

fn from(nonzero: NonZeroIsize) -> Self

Converts a NonZeroIsize into an isize

impl From<NonZeroU8> for NonZeroIsize

fn from(small: NonZeroU8) -> Self

Converts NonZeroU8 to NonZeroIsize losslessly.

impl FromStr for NonZeroIsize

type Err = ParseIntError

The associated error which can be returned from parsing.

fn from_str(src: &str) -> Result<Self, Self::Err>

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

impl Hash for NonZeroIsize

fn hash<H>(&self, state: &mut H)

where H: Hasher,

Feeds this value into the given Hasher.

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

where Self: Sized,

Feeds a slice of this type into the given Hasher.

impl LowerHex for NonZeroIsize

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

Formats the value using the given formatter.

impl Neg for &NonZeroIsize

type Output = <NonZeroIsize as Neg>::Output

The resulting type after applying the - operator.

fn neg(self) -> <NonZeroIsize as Neg>::Output

Performs the unary - operation.

impl Neg for NonZeroIsize

type Output = NonZeroIsize

The resulting type after applying the - operator.

fn neg(self) -> Self

Performs the unary - operation.

impl Octal for NonZeroIsize

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

Formats the value using the given formatter.

impl Ord for NonZeroIsize

fn cmp(&self, other: &Self) -> 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 for NonZeroIsize

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

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

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

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl PartialOrd for NonZeroIsize

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

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

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

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

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

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

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

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

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

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

impl TryFrom<NonZeroI128> for NonZeroIsize

fn try_from(value: NonZeroI128) -> Result<Self, Self::Error>

Attempts to convert NonZeroI128 to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroI32> for NonZeroIsize

fn try_from(value: NonZeroI32) -> Result<Self, Self::Error>

Attempts to convert NonZeroI32 to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroI64> for NonZeroIsize

fn try_from(value: NonZeroI64) -> Result<Self, Self::Error>

Attempts to convert NonZeroI64 to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroI128

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroI128.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroI16

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroI16.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroI32

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroI32.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroI64

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroI64.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroI8

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroI8.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroU128

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroU128.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroU16

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroU16.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroU32

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroU32.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroU64

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroU64.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroU8

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroU8.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroIsize> for NonZeroUsize

fn try_from(value: NonZeroIsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroIsize to NonZeroUsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroU128> for NonZeroIsize

fn try_from(value: NonZeroU128) -> Result<Self, Self::Error>

Attempts to convert NonZeroU128 to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroU16> for NonZeroIsize

fn try_from(value: NonZeroU16) -> Result<Self, Self::Error>

Attempts to convert NonZeroU16 to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroU32> for NonZeroIsize

fn try_from(value: NonZeroU32) -> Result<Self, Self::Error>

Attempts to convert NonZeroU32 to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroU64> for NonZeroIsize

fn try_from(value: NonZeroU64) -> Result<Self, Self::Error>

Attempts to convert NonZeroU64 to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<NonZeroUsize> for NonZeroIsize

fn try_from(value: NonZeroUsize) -> Result<Self, Self::Error>

Attempts to convert NonZeroUsize to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl TryFrom<isize> for NonZeroIsize

fn try_from(value: isize) -> Result<Self, Self::Error>

Attempts to convert isize to NonZeroIsize.

type Error = TryFromIntError

The type returned in the event of a conversion error.

impl UpperHex for NonZeroIsize

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

Formats the value using the given formatter.

impl Copy for NonZeroIsize

impl Eq for NonZeroIsize

impl StructuralEq for NonZeroIsize

impl StructuralPartialEq for NonZeroIsize