# Primitive Type u1281.26.0[−]

## Expand description

The 128-bit unsigned integer type.

## Implementations

Converts a string slice in a given base to an integer.

The string is expected to be an optional `+`

sign
followed by digits.
Leading and trailing whitespace represent an error.
Digits are a subset of these characters, depending on `radix`

:

`0-9`

`a-z`

`A-Z`

# Panics

This function panics if `radix`

is not in the range from 2 to 36.

# Examples

Basic usage:

`assert_eq!(u128::from_str_radix("A", 16), Ok(10));`

RunShifts the bits to the left by a specified amount, `n`

,
wrapping the truncated bits to the end of the resulting integer.

Please note this isn’t the same operation as the `<<`

shifting operator!

# Examples

Basic usage:

```
let n = 0x13f40000000000000000000000004f76u128;
let m = 0x4f7613f4;
assert_eq!(n.rotate_left(16), m);
```

RunShifts the bits to the right by a specified amount, `n`

,
wrapping the truncated bits to the beginning of the resulting
integer.

Please note this isn’t the same operation as the `>>`

shifting operator!

# Examples

Basic usage:

```
let n = 0x4f7613f4u128;
let m = 0x13f40000000000000000000000004f76;
assert_eq!(n.rotate_right(16), m);
```

RunReverses the order of bits in the integer. The least significant bit becomes the most significant bit, second least-significant bit becomes second most-significant bit, etc.

# Examples

Basic usage:

```
let n = 0x12345678901234567890123456789012u128;
let m = n.reverse_bits();
assert_eq!(m, 0x48091e6a2c48091e6a2c48091e6a2c48);
assert_eq!(0, 0u128.reverse_bits());
```

RunConverts an integer from little endian to the target’s endianness.

On little endian this is a no-op. On big endian the bytes are swapped.

# Examples

Basic usage:

```
let n = 0x1Au128;
if cfg!(target_endian = "little") {
assert_eq!(u128::from_le(n), n)
} else {
assert_eq!(u128::from_le(n), n.swap_bytes())
}
```

Run## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer addition. Computes `self + rhs`

, assuming overflow
cannot occur.

# Safety

This results in undefined behavior when
`self + rhs > u128::MAX`

or `self + rhs < u128::MIN`

,
i.e. when `checked_add`

would return `None`

.

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer subtraction. Computes `self - rhs`

, assuming overflow
cannot occur.

# Safety

This results in undefined behavior when
`self - rhs > u128::MAX`

or `self - rhs < u128::MIN`

,
i.e. when `checked_sub`

would return `None`

.

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked integer multiplication. Computes `self * rhs`

, assuming overflow
cannot occur.

# Safety

This results in undefined behavior when
`self * rhs > u128::MAX`

or `self * rhs < u128::MIN`

,
i.e. when `checked_mul`

would return `None`

.

Returns the logarithm of the number with respect to an arbitrary base.

This method might not be optimized owing to implementation details;
`log2`

can produce results more efficiently for base 2, and `log10`

can produce results more efficiently for base 10.

# Panics

When the number is negative, zero, or if the base is not at least 2; it panics in debug mode and the return value is wrapped to 0 in release mode (the only situation in which the method can return 0).

# Examples

```
#![feature(int_log)]
assert_eq!(5u128.log(5), 1);
```

RunReturns the logarithm of the number with respect to an arbitrary base.

Returns `None`

if the number is zero, or if the base is not at least 2.

This method might not be optimized owing to implementation details;
`checked_log2`

can produce results more efficiently for base 2, and
`checked_log10`

can produce results more efficiently for base 10.

# Examples

```
#![feature(int_log)]
assert_eq!(5u128.checked_log(5), Some(1));
```

Run## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked shift left. Computes `self << rhs`

, assuming that
`rhs`

is less than the number of bits in `self`

.

# Safety

This results in undefined behavior if `rhs`

is larger than
or equal to the number of bits in `self`

,
i.e. when `checked_shl`

would return `None`

.

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

## 🔬 This is a nightly-only experimental API. (`unchecked_math`

#85122)

niche optimization path

Unchecked shift right. Computes `self >> rhs`

, assuming that
`rhs`

is less than the number of bits in `self`

.

# Safety

This results in undefined behavior if `rhs`

is larger than
or equal to the number of bits in `self`

,
i.e. when `checked_shr`

would return `None`

.

Wrapping (modular) multiplication. Computes `self * rhs`

, wrapping around at the boundary of the type.

# Examples

Basic usage:

Please note that this example is shared between integer types.
Which explains why `u8`

is used here.

```
assert_eq!(10u8.wrapping_mul(12), 120);
assert_eq!(25u8.wrapping_mul(12), 44);
```

RunWrapping (modular) division. Computes `self / rhs`

.
Wrapped division on unsigned types is just normal division.
There’s no way wrapping could ever happen.
This function exists, so that all operations
are accounted for in the wrapping operations.

# Examples

Basic usage:

`assert_eq!(100u128.wrapping_div(10), 10);`

RunWrapping Euclidean division. Computes `self.div_euclid(rhs)`

.
Wrapped division on unsigned types is just normal division.
There’s no way wrapping could ever happen.
This function exists, so that all operations
are accounted for in the wrapping operations.
Since, for the positive integers, all common
definitions of division are equal, this
is exactly equal to `self.wrapping_div(rhs)`

.

# Examples

Basic usage:

`assert_eq!(100u128.wrapping_div_euclid(10), 10);`

RunWrapping (modular) remainder. Computes `self % rhs`

.
Wrapped remainder calculation on unsigned types is
just the regular remainder calculation.
There’s no way wrapping could ever happen.
This function exists, so that all operations
are accounted for in the wrapping operations.

# Examples

Basic usage:

`assert_eq!(100u128.wrapping_rem(10), 0);`

RunWrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`

.
Wrapped modulo calculation on unsigned types is
just the regular remainder calculation.
There’s no way wrapping could ever happen.
This function exists, so that all operations
are accounted for in the wrapping operations.
Since, for the positive integers, all common
definitions of division are equal, this
is exactly equal to `self.wrapping_rem(rhs)`

.

# Examples

Basic usage:

`assert_eq!(100u128.wrapping_rem_euclid(10), 0);`

RunWrapping (modular) negation. Computes `-self`

,
wrapping around at the boundary of the type.

Since unsigned types do not have negative equivalents
all applications of this function will wrap (except for `-0`

).
For values smaller than the corresponding signed type’s maximum
the result is the same as casting the corresponding signed value.
Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)`

where
`MAX`

is the corresponding signed type’s maximum.

# Examples

Basic usage:

Please note that this example is shared between integer types.
Which explains why `i8`

is used here.

```
assert_eq!(100i8.wrapping_neg(), -100);
assert_eq!((-128i8).wrapping_neg(), -128);
```

RunPanic-free bitwise shift-left; yields `self << mask(rhs)`

,
where `mask`

removes any high-order bits of `rhs`

that
would cause the shift to exceed the bitwidth of the type.

Note that this is *not* the same as a rotate-left; the
RHS of a wrapping shift-left is restricted to the range
of the type, rather than the bits shifted out of the LHS
being returned to the other end. The primitive integer
types all implement a `rotate_left`

function,
which may be what you want instead.

# Examples

Basic usage:

```
assert_eq!(1u128.wrapping_shl(7), 128);
assert_eq!(1u128.wrapping_shl(128), 1);
```

RunPanic-free bitwise shift-right; yields `self >> mask(rhs)`

,
where `mask`

removes any high-order bits of `rhs`

that
would cause the shift to exceed the bitwidth of the type.

Note that this is *not* the same as a rotate-right; the
RHS of a wrapping shift-right is restricted to the range
of the type, rather than the bits shifted out of the LHS
being returned to the other end. The primitive integer
types all implement a `rotate_right`

function,
which may be what you want instead.

# Examples

Basic usage:

```
assert_eq!(128u128.wrapping_shr(7), 1);
assert_eq!(128u128.wrapping_shr(128), 128);
```

RunCalculates `self`

+ `rhs`

Returns a tuple of the addition along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

# Examples

Basic usage

```
assert_eq!(5u128.overflowing_add(2), (7, false));
assert_eq!(u128::MAX.overflowing_add(1), (0, true));
```

RunCalculates `self`

- `rhs`

Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

# Examples

Basic usage

```
assert_eq!(5u128.overflowing_sub(2), (3, false));
assert_eq!(0u128.overflowing_sub(1), (u128::MAX, true));
```

RunCalculates the multiplication of `self`

and `rhs`

.

Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would have occurred then the wrapped value is returned.

# Examples

Basic usage:

Please note that this example is shared between integer types.
Which explains why `u32`

is used here.

```
assert_eq!(5u32.overflowing_mul(2), (10, false));
assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
```

RunCalculates the divisor when `self`

is divided by `rhs`

.

Returns a tuple of the divisor along with a boolean indicating
whether an arithmetic overflow would occur. Note that for unsigned
integers overflow never occurs, so the second value is always
`false`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage

`assert_eq!(5u128.overflowing_div(2), (2, false));`

RunCalculates the quotient of Euclidean division `self.div_euclid(rhs)`

.

Returns a tuple of the divisor along with a boolean indicating
whether an arithmetic overflow would occur. Note that for unsigned
integers overflow never occurs, so the second value is always
`false`

.
Since, for the positive integers, all common
definitions of division are equal, this
is exactly equal to `self.overflowing_div(rhs)`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage

`assert_eq!(5u128.overflowing_div_euclid(2), (2, false));`

RunCalculates the remainder when `self`

is divided by `rhs`

.

Returns a tuple of the remainder after dividing along with a boolean
indicating whether an arithmetic overflow would occur. Note that for
unsigned integers overflow never occurs, so the second value is
always `false`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage

`assert_eq!(5u128.overflowing_rem(2), (1, false));`

RunCalculates the remainder `self.rem_euclid(rhs)`

as if by Euclidean division.

Returns a tuple of the modulo after dividing along with a boolean
indicating whether an arithmetic overflow would occur. Note that for
unsigned integers overflow never occurs, so the second value is
always `false`

.
Since, for the positive integers, all common
definitions of division are equal, this operation
is exactly equal to `self.overflowing_rem(rhs)`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage

`assert_eq!(5u128.overflowing_rem_euclid(2), (1, false));`

RunNegates self in an overflowing fashion.

Returns `!self + 1`

using wrapping operations to return the value
that represents the negation of this unsigned value. Note that for
positive unsigned values overflow always occurs, but negating 0 does
not overflow.

# Examples

Basic usage

```
assert_eq!(0u128.overflowing_neg(), (0, false));
assert_eq!(2u128.overflowing_neg(), (-2i32 as u128, true));
```

RunShifts self left by `rhs`

bits.

Returns a tuple of the shifted version of self along with a boolean indicating whether the shift value was larger than or equal to the number of bits. If the shift value is too large, then value is masked (N-1) where N is the number of bits, and this value is then used to perform the shift.

# Examples

Basic usage

```
assert_eq!(0x1u128.overflowing_shl(4), (0x10, false));
assert_eq!(0x1u128.overflowing_shl(132), (0x10, true));
```

RunShifts self right by `rhs`

bits.

Returns a tuple of the shifted version of self along with a boolean indicating whether the shift value was larger than or equal to the number of bits. If the shift value is too large, then value is masked (N-1) where N is the number of bits, and this value is then used to perform the shift.

# Examples

Basic usage

```
assert_eq!(0x10u128.overflowing_shr(4), (0x1, false));
assert_eq!(0x10u128.overflowing_shr(132), (0x1, true));
```

RunCalculates the least remainder of `self (mod rhs)`

.

Since, for the positive integers, all common
definitions of division are equal, this
is exactly equal to `self % rhs`

.

# Panics

This function will panic if `rhs`

is 0.

# Examples

Basic usage:

`assert_eq!(7u128.rem_euclid(4), 3); // or any other integer type`

RunReturns the smallest power of two greater than or equal to `self`

.

When return value overflows (i.e., `self > (1 << (N-1))`

for type
`uN`

), it panics in debug mode and return value is wrapped to 0 in
release mode (the only situation in which method can return 0).

# Examples

Basic usage:

```
assert_eq!(2u128.next_power_of_two(), 2);
assert_eq!(3u128.next_power_of_two(), 4);
```

RunReturns the smallest power of two greater than or equal to `n`

. If
the next power of two is greater than the type’s maximum value,
`None`

is returned, otherwise the power of two is wrapped in `Some`

.

# Examples

Basic usage:

```
assert_eq!(2u128.checked_next_power_of_two(), Some(2));
assert_eq!(3u128.checked_next_power_of_two(), Some(4));
assert_eq!(u128::MAX.checked_next_power_of_two(), None);
```

Run## 🔬 This is a nightly-only experimental API. (`wrapping_next_power_of_two`

#32463)

needs decision on wrapping behaviour

## 🔬 This is a nightly-only experimental API. (`wrapping_next_power_of_two`

#32463)

needs decision on wrapping behaviour

Returns the smallest power of two greater than or equal to `n`

. If
the next power of two is greater than the type’s maximum value,
the return value is wrapped to `0`

.

# Examples

Basic usage:

```
#![feature(wrapping_next_power_of_two)]
assert_eq!(2u128.wrapping_next_power_of_two(), 2);
assert_eq!(3u128.wrapping_next_power_of_two(), 4);
assert_eq!(u128::MAX.wrapping_next_power_of_two(), 0);
```

RunReturn the memory representation of this integer as a byte array in native byte order.

As the target platform’s native endianness is used, portable code
should use `to_be_bytes`

or `to_le_bytes`

, as appropriate,
instead.

# Examples

```
let bytes = 0x12345678901234567890123456789012u128.to_ne_bytes();
assert_eq!(
bytes,
if cfg!(target_endian = "big") {
[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12]
} else {
[0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]
}
);
```

RunCreate a native endian integer value from its representation as a byte array in big endian.

# Examples

```
let value = u128::from_be_bytes([0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12]);
assert_eq!(value, 0x12345678901234567890123456789012);
```

RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:

```
use std::convert::TryInto;
fn read_be_u128(input: &mut &[u8]) -> u128 {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<u128>());
*input = rest;
u128::from_be_bytes(int_bytes.try_into().unwrap())
}
```

RunCreate a native endian integer value from its representation as a byte array in little endian.

# Examples

```
let value = u128::from_le_bytes([0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]);
assert_eq!(value, 0x12345678901234567890123456789012);
```

RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:

```
use std::convert::TryInto;
fn read_le_u128(input: &mut &[u8]) -> u128 {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<u128>());
*input = rest;
u128::from_le_bytes(int_bytes.try_into().unwrap())
}
```

RunCreate a native endian integer value from its memory representation as a byte array in native endianness.

As the target platform’s native endianness is used, portable code
likely wants to use `from_be_bytes`

or `from_le_bytes`

, as
appropriate instead.

# Examples

```
let value = u128::from_ne_bytes(if cfg!(target_endian = "big") {
[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12]
} else {
[0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]
});
assert_eq!(value, 0x12345678901234567890123456789012);
```

RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:

```
use std::convert::TryInto;
fn read_ne_u128(input: &mut &[u8]) -> u128 {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<u128>());
*input = rest;
u128::from_ne_bytes(int_bytes.try_into().unwrap())
}
```

Run## 👎 Deprecating in a future Rust version: replaced by the `MIN`

associated constant on this type

replaced by the `MIN`

associated constant on this type

New code should prefer to use
`u128::MIN`

instead.

Returns the smallest value that can be represented by this integer type.

## Trait Implementations

Performs the `+=`

operation. Read more

Performs the `+=`

operation. Read more

Performs the `&=`

operation. Read more

Performs the `&=`

operation. Read more

#### type Output = NonZeroU128

#### type Output = NonZeroU128

The resulting type after applying the `|`

operator.

Performs the `|`

operation. Read more

Performs the `|=`

operation. Read more

Performs the `|=`

operation. Read more

Performs the `^=`

operation. Read more

Performs the `^=`

operation. Read more

This operation rounds towards zero, truncating any fractional part of the exact result.

# Panics

This operation will panic if `other == 0`

.

Performs the `/=`

operation. Read more

Performs the `/=`

operation. Read more

Converts a `NonZeroU128`

into an `u128`

#### type Err = ParseIntError

#### type Err = ParseIntError

The associated error which can be returned from parsing.

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 or equal to (for `self`

and `other`

) and is used by the `>=`

operator. Read more

This operation satisfies `n % d == n - (n / d) * d`

. The
result has the same sign as the left operand.

# Panics

This operation will panic if `other == 0`

.

Performs the `%=`

operation. Read more

Performs the `%=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `<<=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

Performs the `>>=`

operation. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *successor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *predecessor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *successor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the value that would be obtained by taking the *predecessor*
of `self`

`count`

times. Read more

## 🔬 This is a nightly-only experimental API. (`step_trait`

#42168)

recently redesigned

Returns the number of *successor* steps required to get from `start`

to `end`

. Read more

Performs the `-=`

operation. Read more

Performs the `-=`

operation. Read more

Try to create the target number type from a source number type. This returns an error if the source value is outside of the range of the target type.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Try to create the target number type from a source number type. This returns an error if the source value is outside of the range of the target type.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

Try to create the target number type from a source number type. This returns an error if the source value is outside of the range of the target type.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

#### type Error = TryFromIntError

#### type Error = TryFromIntError

The type returned in the event of a conversion error.

## Auto Trait Implementations

### impl RefUnwindSafe for u128

### impl UnwindSafe for u128

## Blanket Implementations

Mutably borrows from an owned value. Read more