Struct std::num::NonZeroIsize

1.34.0 · source · 
pub struct NonZeroIsize(_);
Expand description

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>());
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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 value as a primitive type.

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);
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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);
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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());
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Checked absolute value. Checks for overflow and returns None if self == isize::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());
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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());
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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());
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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());
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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());
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🔬This is a nightly-only experimental API. (nonzero_negation_ops #102443)

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

Example
#![feature(nonzero_negation_ops)]

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

assert!(neg_five.is_negative());
assert!(!pos_five.is_negative());
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🔬This is a nightly-only experimental API. (nonzero_negation_ops #102443)

Checked negation. Computes -self, returning None if self == i32::MIN.

Example
#![feature(nonzero_negation_ops)]

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);
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🔬This is a nightly-only experimental API. (nonzero_negation_ops #102443)

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

See isize::overflowing_neg for documentation on overflow behaviour.

Example
#![feature(nonzero_negation_ops)]

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));
Run
🔬This is a nightly-only experimental API. (nonzero_negation_ops #102443)

Saturating negation. Computes -self, returning MAX if self == i32::MIN instead of overflowing.

Example
#![feature(nonzero_negation_ops)]

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);
Run
🔬This is a nightly-only experimental API. (nonzero_negation_ops #102443)

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

See isize::wrapping_neg for documentation on overflow behaviour.

Example
#![feature(nonzero_negation_ops)]

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);
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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));
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Multiplies two non-zero integers together. Return isize::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));
Run
🔬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) });
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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));
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Raise non-zero value to an integer power. Return isize::MIN or isize::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));
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🔬This is a nightly-only experimental API. (nonzero_min_max #89065)

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
#![feature(nonzero_min_max)]

assert_eq!(NonZeroIsize::MIN.get(), isize::MIN);
Run
🔬This is a nightly-only experimental API. (nonzero_min_max #89065)

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
#![feature(nonzero_min_max)]

assert_eq!(NonZeroIsize::MAX.get(), isize::MAX);
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The size of this non-zero integer type in bits.

This value is equal to isize::BITS.

Examples

assert_eq!(NonZeroIsize::BITS, isize::BITS);
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Trait Implementations§

Formats the value using the given formatter.
The resulting type after applying the | operator.
Performs the | operation. Read more
The resulting type after applying the | operator.
Performs the | operation. Read more
The resulting type after applying the | operator.
Performs the | operation. Read more
Performs the |= operation. Read more
Performs the |= operation. Read more
Returns a copy of the value. Read more
Performs copy-assignment from source. Read more
Formats the value using the given formatter. Read more
Formats the value using the given formatter. Read more

Converts NonZeroI16 to NonZeroIsize losslessly.

Converts NonZeroI8 to NonZeroIsize losslessly.

Converts a NonZeroIsize into an isize

Converts NonZeroU8 to NonZeroIsize losslessly.

The associated error which can be returned from parsing.
Parses a string s to return a value of this type. Read more
Feeds this value into the given Hasher. Read more
Feeds a slice of this type into the given Hasher. Read more
Formats the value using the given formatter.
Formats the value using the given formatter.
This method returns an Ordering between self and other. Read more
Compares and returns the maximum of two values. Read more
Compares and returns the minimum of two values. Read more
Restrict a value to a certain interval. Read more
This method tests for self and other values to be equal, and is used by ==. Read more
This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason. 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
This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more

Attempts to convert NonZeroI128 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroI32 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroI64 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI128.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI16.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI32.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI64.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroI8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU128.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU16.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU32.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU64.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroIsize to NonZeroUsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU128 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU16 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU32 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU64 to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert NonZeroUsize to NonZeroIsize.

The type returned in the event of a conversion error.

Attempts to convert isize to NonZeroIsize.

The type returned in the event of a conversion error.
Formats the value using the given formatter.

Auto Trait Implementations§

Blanket Implementations§

Gets the TypeId of self. Read more
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more

Returns the argument unchanged.

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.