# Trait num_traits::int::PrimInt[−][src]

``````pub trait PrimInt: Sized + Copy + Num + NumCast + Bounded + PartialOrd + Ord + Eq + Not<Output = Self> + BitAnd<Output = Self> + BitOr<Output = Self> + BitXor<Output = Self> + Shl<usize, Output = Self> + Shr<usize, Output = Self> + CheckedAdd<Output = Self> + CheckedSub<Output = Self> + CheckedMul<Output = Self> + CheckedDiv<Output = Self> + Saturating {
Show 16 methods    fn count_ones(self) -> u32;
fn count_zeros(self) -> u32;
fn trailing_zeros(self) -> u32;
fn rotate_left(self, n: u32) -> Self;
fn rotate_right(self, n: u32) -> Self;
fn signed_shl(self, n: u32) -> Self;
fn signed_shr(self, n: u32) -> Self;
fn unsigned_shl(self, n: u32) -> Self;
fn unsigned_shr(self, n: u32) -> Self;
fn swap_bytes(self) -> Self;
fn from_be(x: Self) -> Self;
fn from_le(x: Self) -> Self;
fn to_be(self) -> Self;
fn to_le(self) -> Self;
fn pow(self, exp: u32) -> Self;
}``````
Expand description

Generic trait for primitive integers.

The `PrimInt` trait is an abstraction over the builtin primitive integer types (e.g., `u8`, `u32`, `isize`, `i128`, …). It inherits the basic numeric traits and extends them with bitwise operators and non-wrapping arithmetic.

The trait explicitly inherits `Copy`, `Eq`, `Ord`, and `Sized`. The intention is that all types implementing this trait behave like primitive types that are passed by value by default and behave like builtin integers. Furthermore, the types are expected to expose the integer value in binary representation and support bitwise operators. The standard bitwise operations (e.g., bitwise-and, bitwise-or, right-shift, left-shift) are inherited and the trait extends these with introspective queries (e.g., `PrimInt::count_ones()`, `PrimInt::leading_zeros()`), bitwise combinators (e.g., `PrimInt::rotate_left()`), and endianness converters (e.g., `PrimInt::to_be()`).

All `PrimInt` types are expected to be fixed-width binary integers. The width can be queried via `T::zero().count_zeros()`. The trait currently lacks a way to query the width at compile-time.

While a default implementation for all builtin primitive integers is provided, the trait is in no way restricted to these. Other integer types that fulfil the requirements are free to implement the trait was well.

This trait and many of the method names originate in the unstable `core::num::Int` trait from the rust standard library. The original trait was never stabilized and thus removed from the standard library.

## Required methods

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

##### Examples
``````use num_traits::PrimInt;

let n = 0b01001100u8;

assert_eq!(n.count_ones(), 3);``````

Returns the number of zeros in the binary representation of `self`.

##### Examples
``````use num_traits::PrimInt;

let n = 0b01001100u8;

assert_eq!(n.count_zeros(), 5);``````

Returns the number of leading zeros in the binary representation of `self`.

##### Examples
``````use num_traits::PrimInt;

let n = 0b0101000u16;

Returns the number of trailing zeros in the binary representation of `self`.

##### Examples
``````use num_traits::PrimInt;

let n = 0b0101000u16;

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

Shifts the bits to the left by a specified amount, `n`, wrapping the truncated bits to the end of the resulting integer.

##### Examples
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFu64;
let m = 0x3456789ABCDEF012u64;

assert_eq!(n.rotate_left(12), m);``````

Shifts the bits to the right by a specified amount, `n`, wrapping the truncated bits to the beginning of the resulting integer.

##### Examples
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFu64;
let m = 0xDEF0123456789ABCu64;

assert_eq!(n.rotate_right(12), m);``````

Shifts the bits to the left by a specified amount, `n`, filling zeros in the least significant bits.

This is bitwise equivalent to signed `Shl`.

##### Examples
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFu64;
let m = 0x3456789ABCDEF000u64;

assert_eq!(n.signed_shl(12), m);``````

Shifts the bits to the right by a specified amount, `n`, copying the “sign bit” in the most significant bits even for unsigned types.

This is bitwise equivalent to signed `Shr`.

##### Examples
``````use num_traits::PrimInt;

let n = 0xFEDCBA9876543210u64;
let m = 0xFFFFEDCBA9876543u64;

assert_eq!(n.signed_shr(12), m);``````

Shifts the bits to the left by a specified amount, `n`, filling zeros in the least significant bits.

This is bitwise equivalent to unsigned `Shl`.

##### Examples
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFi64;
let m = 0x3456789ABCDEF000i64;

assert_eq!(n.unsigned_shl(12), m);``````

Shifts the bits to the right by a specified amount, `n`, filling zeros in the most significant bits.

This is bitwise equivalent to unsigned `Shr`.

##### Examples
``````use num_traits::PrimInt;

let n = -8i8; // 0b11111000
let m = 62i8; // 0b00111110

assert_eq!(n.unsigned_shr(2), m);``````

Reverses the byte order of the integer.

##### Examples
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFu64;
let m = 0xEFCDAB8967452301u64;

assert_eq!(n.swap_bytes(), m);``````

Convert an integer from big endian to the target’s endianness.

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

##### Examples
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFu64;

if cfg!(target_endian = "big") {
assert_eq!(u64::from_be(n), n)
} else {
assert_eq!(u64::from_be(n), n.swap_bytes())
}``````

Convert 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
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFu64;

if cfg!(target_endian = "little") {
assert_eq!(u64::from_le(n), n)
} else {
assert_eq!(u64::from_le(n), n.swap_bytes())
}``````

Convert `self` to big endian from the target’s endianness.

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

##### Examples
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFu64;

if cfg!(target_endian = "big") {
assert_eq!(n.to_be(), n)
} else {
assert_eq!(n.to_be(), n.swap_bytes())
}``````

Convert `self` to little endian from the target’s endianness.

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

##### Examples
``````use num_traits::PrimInt;

let n = 0x0123456789ABCDEFu64;

if cfg!(target_endian = "little") {
assert_eq!(n.to_le(), n)
} else {
assert_eq!(n.to_le(), n.swap_bytes())
}``````

Raises self to the power of `exp`, using exponentiation by squaring.

##### Examples
``````use num_traits::PrimInt;

assert_eq!(2i32.pow(4), 16);``````