Primitive Type usize [−]
The pointer-sized signed integer type.
Methods
impl usize
fn min_value() -> usize
Returns the smallest value that can be represented by this integer type.
fn max_value() -> usize
Returns the largest value that can be represented by this integer type.
fn from_str_radix(src: &str, radix: u32) -> Result<usize, ParseIntError>
Converts a string slice in a given base to an integer.
Leading and trailing whitespace represent an error.
Arguments
- src - A string slice
- radix - The base to use. Must lie in the range [2 .. 36]
Return value
Err(ParseIntError) if the string did not represent a valid number.
Otherwise, Ok(n) where n is the integer represented by src.
fn count_ones(self) -> u32
Returns the number of ones in the binary representation of self.
Examples
fn main() { let n = 0b01001100u8; assert_eq!(n.count_ones(), 3); }let n = 0b01001100u8; assert_eq!(n.count_ones(), 3);
fn count_zeros(self) -> u32
Returns the number of zeros in the binary representation of self.
Examples
fn main() { let n = 0b01001100u8; assert_eq!(n.count_zeros(), 5); }let n = 0b01001100u8; assert_eq!(n.count_zeros(), 5);
fn leading_zeros(self) -> u32
Returns the number of leading zeros in the binary representation
of self.
Examples
fn main() { let n = 0b0101000u16; assert_eq!(n.leading_zeros(), 10); }let n = 0b0101000u16; assert_eq!(n.leading_zeros(), 10);
fn trailing_zeros(self) -> u32
Returns the number of trailing zeros in the binary representation
of self.
Examples
fn main() { let n = 0b0101000u16; assert_eq!(n.trailing_zeros(), 3); }let n = 0b0101000u16; assert_eq!(n.trailing_zeros(), 3);
fn rotate_left(self, n: u32) -> usize
Shifts the bits to the left by a specified amount, n,
wrapping the truncated bits to the end of the resulting integer.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; let m = 0x3456789ABCDEF012u64; assert_eq!(n.rotate_left(12), m); }let n = 0x0123456789ABCDEFu64; let m = 0x3456789ABCDEF012u64; assert_eq!(n.rotate_left(12), m);
fn rotate_right(self, n: u32) -> usize
Shifts the bits to the right by a specified amount, n,
wrapping the truncated bits to the beginning of the resulting
integer.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; let m = 0xDEF0123456789ABCu64; assert_eq!(n.rotate_right(12), m); }let n = 0x0123456789ABCDEFu64; let m = 0xDEF0123456789ABCu64; assert_eq!(n.rotate_right(12), m);
fn swap_bytes(self) -> usize
Reverses the byte order of the integer.
Examples
fn main() { let n = 0x0123456789ABCDEFu64; let m = 0xEFCDAB8967452301u64; assert_eq!(n.swap_bytes(), m); }let n = 0x0123456789ABCDEFu64; let m = 0xEFCDAB8967452301u64; assert_eq!(n.swap_bytes(), m);
fn from_be(x: usize) -> usize
Converts 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
fn main() { 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()) } }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()) }
fn from_le(x: usize) -> usize
Converts 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
fn main() { 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()) } }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()) }
fn to_be(self) -> usize
Converts 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
fn main() { let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "big") { assert_eq!(n.to_be(), n) } else { assert_eq!(n.to_be(), n.swap_bytes()) } }let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "big") { assert_eq!(n.to_be(), n) } else { assert_eq!(n.to_be(), n.swap_bytes()) }
fn to_le(self) -> usize
Converts 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
fn main() { let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "little") { assert_eq!(n.to_le(), n) } else { assert_eq!(n.to_le(), n.swap_bytes()) } }let n = 0x0123456789ABCDEFu64; if cfg!(target_endian = "little") { assert_eq!(n.to_le(), n) } else { assert_eq!(n.to_le(), n.swap_bytes()) }
fn checked_add(self, other: usize) -> Option<usize>
Checked integer addition. Computes self + other, returning None
if overflow occurred.
Examples
fn main() { assert_eq!(5u16.checked_add(65530), Some(65535)); assert_eq!(6u16.checked_add(65530), None); }assert_eq!(5u16.checked_add(65530), Some(65535)); assert_eq!(6u16.checked_add(65530), None);
fn checked_sub(self, other: usize) -> Option<usize>
Checked integer subtraction. Computes self - other, returning
None if underflow occurred.
Examples
fn main() { assert_eq!((-127i8).checked_sub(1), Some(-128)); assert_eq!((-128i8).checked_sub(1), None); }assert_eq!((-127i8).checked_sub(1), Some(-128)); assert_eq!((-128i8).checked_sub(1), None);
fn checked_mul(self, other: usize) -> Option<usize>
Checked integer multiplication. Computes self * other, returning
None if underflow or overflow occurred.
Examples
fn main() { assert_eq!(5u8.checked_mul(51), Some(255)); assert_eq!(5u8.checked_mul(52), None); }assert_eq!(5u8.checked_mul(51), Some(255)); assert_eq!(5u8.checked_mul(52), None);
fn checked_div(self, v: usize) -> Option<usize>
Checked integer division. Computes self / other, returning None
if other == 0 or the operation results in underflow or overflow.
Examples
fn main() { assert_eq!((-127i8).checked_div(-1), Some(127)); assert_eq!((-128i8).checked_div(-1), None); assert_eq!((1i8).checked_div(0), None); }assert_eq!((-127i8).checked_div(-1), Some(127)); assert_eq!((-128i8).checked_div(-1), None); assert_eq!((1i8).checked_div(0), None);
fn saturating_add(self, other: usize) -> usize
Saturating integer addition. Computes self + other, saturating at
the numeric bounds instead of overflowing.
fn saturating_sub(self, other: usize) -> usize
Saturating integer subtraction. Computes self - other, saturating
at the numeric bounds instead of overflowing.
fn wrapping_add(self, rhs: usize) -> usize
Wrapping (modular) addition. Computes self + other,
wrapping around at the boundary of the type.
fn wrapping_sub(self, rhs: usize) -> usize
Wrapping (modular) subtraction. Computes self - other,
wrapping around at the boundary of the type.
fn wrapping_mul(self, rhs: usize) -> usize
Wrapping (modular) multiplication. Computes self * other, wrapping around at the boundary of the type.
fn wrapping_div(self, rhs: usize) -> usize
Wrapping (modular) division. Computes self / other,
wrapping around at the boundary of the type.
The only case where such wrapping can occur is when one
divides MIN / -1 on a signed type (where MIN is the
negative minimal value for the type); this is equivalent
to -MIN, a positive value that is too large to represent
in the type. In such a case, this function returns MIN
itself.
fn wrapping_rem(self, rhs: usize) -> usize
Wrapping (modular) remainder. Computes self % other,
wrapping around at the boundary of the type.
Such wrap-around never actually occurs mathematically;
implementation artifacts make x % y invalid for MIN / -1 on a signed type (where MIN is the negative
minimal value). In such a case, this function returns 0.
fn wrapping_neg(self) -> usize
Wrapping (modular) negation. Computes -self,
wrapping around at the boundary of the type.
The only case where such wrapping can occur is when one
negates MIN on a signed type (where MIN is the
negative minimal value for the type); this is a positive
value that is too large to represent in the type. In such
a case, this function returns MIN itself.
fn wrapping_shl(self, rhs: u32) -> usize
Panic-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.
fn wrapping_shr(self, rhs: u32) -> usize
Panic-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.
fn pow(self, exp: u32) -> usize
Raises self to the power of exp, using exponentiation by squaring.
Examples
fn main() { assert_eq!(2i32.pow(4), 16); }assert_eq!(2i32.pow(4), 16);
fn is_power_of_two(self) -> bool
Returns true if and only if self == 2^k for some k.
fn next_power_of_two(self) -> usize
Returns the smallest power of two greater than or equal to self.
Unspecified behavior on overflow.
fn checked_next_power_of_two(self) -> Option<usize>
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,
None is returned, otherwise the power of two is wrapped in Some.
Trait Implementations
impl OverflowingOps for usize
fn overflowing_add(self, rhs: usize) -> (usize, bool)
fn overflowing_sub(self, rhs: usize) -> (usize, bool)
fn overflowing_mul(self, rhs: usize) -> (usize, bool)
fn overflowing_div(self, rhs: usize) -> (usize, bool)
fn overflowing_rem(self, rhs: usize) -> (usize, bool)
fn overflowing_neg(self) -> (usize, bool)
fn overflowing_shl(self, rhs: u32) -> (usize, bool)
fn overflowing_shr(self, rhs: u32) -> (usize, bool)
impl Zero for usize
impl One for usize
impl FromStr for usize
type Err = ParseIntError
fn from_str(src: &str) -> Result<usize, ParseIntError>
impl Zeroable for usize
impl Add<usize> for usize
impl<'a> Add<usize> for &'a usize
impl<'a> Add<&'a usize> for usize
impl<'a, 'b> Add<&'a usize> for &'b usize
impl Sub<usize> for usize
impl<'a> Sub<usize> for &'a usize
impl<'a> Sub<&'a usize> for usize
impl<'a, 'b> Sub<&'a usize> for &'b usize
impl Mul<usize> for usize
impl<'a> Mul<usize> for &'a usize
impl<'a> Mul<&'a usize> for usize
impl<'a, 'b> Mul<&'a usize> for &'b usize
impl Div<usize> for usize
This operation rounds towards zero, truncating any fractional part of the exact result.
impl<'a> Div<usize> for &'a usize
impl<'a> Div<&'a usize> for usize
impl<'a, 'b> Div<&'a usize> for &'b usize
impl Rem<usize> for usize
This operation satisfies n % d == n - (n / d) * d. The
result has the same sign as the left operand.