Struct wasmtime_environ::__core::num::NonZeroU8

1.28.0 · source · [−]
#[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>());

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::NonZeroU8::new(u8::MAX).unwrap();

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

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::NonZeroU8::new(0b0101000).unwrap();

assert_eq!(n.trailing_zeros(), 3);
🔬 This is a nightly-only experimental API. (nonzero_ops)

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 = 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));
🔬 This is a nightly-only experimental API. (nonzero_ops)

Add an unsigned integer to a non-zero value. Return u8::MAX on overflow.

Examples
#![feature(nonzero_ops)]

let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;
let max = NonZeroU8::new(u8::MAX)?;

assert_eq!(two, one.saturating_add(1));
assert_eq!(max, max.saturating_add(1));
🔬 This is a nightly-only experimental API. (nonzero_ops)

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 > u8::MAX.

Examples
#![feature(nonzero_ops)]

let one = NonZeroU8::new(1)?;
let two = NonZeroU8::new(2)?;

assert_eq!(two, unsafe { one.unchecked_add(1) });
🔬 This is a nightly-only experimental API. (nonzero_ops)

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 = 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() );
🔬 This is a nightly-only experimental API. (int_log)

Returns the base 2 logarithm of the number, rounded down.

This is the same operation as u8::log2, except that it has no failure cases to worry about since this value can never be zero.

Examples
#![feature(int_log)]

assert_eq!(NonZeroU8::new(7).unwrap().log2(), 2);
assert_eq!(NonZeroU8::new(8).unwrap().log2(), 3);
assert_eq!(NonZeroU8::new(9).unwrap().log2(), 3);
🔬 This is a nightly-only experimental API. (int_log)

Returns the base 10 logarithm of the number, rounded down.

This is the same operation as u8::log10, except that it has no failure cases to worry about since this value can never be zero.

Examples
#![feature(int_log)]

assert_eq!(NonZeroU8::new(99).unwrap().log10(), 1);
assert_eq!(NonZeroU8::new(100).unwrap().log10(), 2);
assert_eq!(NonZeroU8::new(101).unwrap().log10(), 2);
🔬 This is a nightly-only experimental API. (nonzero_ops)

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 = 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));
🔬 This is a nightly-only experimental API. (nonzero_ops)

Multiply two non-zero integers together. Return u8::MAX on overflow.

Examples
#![feature(nonzero_ops)]

let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;
let max = NonZeroU8::new(u8::MAX)?;

assert_eq!(four, two.saturating_mul(two));
assert_eq!(max, four.saturating_mul(max));
🔬 This is a nightly-only experimental API. (nonzero_ops)

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 > u8::MAX.

Examples
#![feature(nonzero_ops)]

let two = NonZeroU8::new(2)?;
let four = NonZeroU8::new(4)?;

assert_eq!(four, unsafe { two.unchecked_mul(two) });
🔬 This is a nightly-only experimental API. (nonzero_ops)

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 = 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));
🔬 This is a nightly-only experimental API. (nonzero_ops)

Raise 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));

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::NonZeroU8::new(8).unwrap();
assert!(eight.is_power_of_two());
let ten = std::num::NonZeroU8::new(10).unwrap();
assert!(!ten.is_power_of_two());
🔬 This is a nightly-only experimental API. (nonzero_min_max)

The smallest value that can be represented by this non-zero integer type, 1.

Examples
#![feature(nonzero_min_max)]

assert_eq!(NonZeroU8::MIN.get(), 1u8);
🔬 This is a nightly-only experimental API. (nonzero_min_max)

The largest value that can be represented by this non-zero integer type, equal to u8::MAX.

Examples
#![feature(nonzero_min_max)]

assert_eq!(NonZeroU8::MAX.get(), u8::MAX);
🔬 This is a nightly-only experimental API. (nonzero_bits)

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

This value is equal to u8::BITS.

Examples
#![feature(nonzero_bits)]

assert_eq!(NonZeroU8::BITS, u8::BITS);

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

Deserialize this value from the given Serde deserializer. Read more

Formats the value using the given formatter. Read more

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

The resulting type after applying the / operator.

Converts NonZeroU8 to NonZeroI32 losslessly.

Converts NonZeroU8 to NonZeroU128 losslessly.

Converts NonZeroU8 to NonZeroIsize losslessly.

Performs the conversion.

Converts NonZeroU8 to NonZeroI64 losslessly.

Converts NonZeroU8 to NonZeroU32 losslessly.

Converts NonZeroU8 to NonZeroI16 losslessly.

Converts NonZeroU8 to NonZeroI128 losslessly.

Converts NonZeroU8 to NonZeroUsize losslessly.

Converts NonZeroU8 to NonZeroU16 losslessly.

Converts a NonZeroU8 into an u8

Converts NonZeroU8 to NonZeroU64 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 !=.

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

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

The resulting type after applying the % operator.

Serialize this value into the given Serde serializer. Read more

Perform the conversion.

Attempts to convert NonZeroI128 to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroI16 to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroI32 to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroI64 to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroI8 to NonZeroU8.

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 NonZeroU128 to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU16 to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU32 to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU64 to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroU8 to NonZeroI8.

The type returned in the event of a conversion error.

Attempts to convert NonZeroUsize to NonZeroU8.

The type returned in the event of a conversion error.

Attempts to convert u8 to NonZeroU8.

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

Compare self to key and return true if they are equal.

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

🔬 This is a nightly-only experimental API. (toowned_clone_into)

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.