isize - Rust (original) (raw)
Primitive Type isize
1.0.0
Expand description
The pointer-sized signed integer type.
The size of this primitive is how many bytes it takes to reference any location in memory. For example, on a 32 bit target, this is 4 bytes and on a 64 bit target, this is 8 bytes.
1.43.0 · Source
The smallest value that can be represented by this integer type (−263 on 64-bit targets).
§Examples
Basic usage:
assert_eq!(isize::MIN, -9223372036854775808);1.43.0 · Source
The largest value that can be represented by this integer type (263 − 1 on 64-bit targets).
§Examples
Basic usage:
assert_eq!(isize::MAX, 9223372036854775807);1.53.0 · Source
The size of this integer type in bits.
§Examples
assert_eq!(isize::BITS, 64);1.0.0 (const: 1.32.0) · Source
Returns the number of ones in the binary representation of self.
§Examples
Basic usage:
let n = 0b100_0000isize;
assert_eq!(n.count_ones(), 1);1.0.0 (const: 1.32.0) · Source
Returns the number of zeros in the binary representation of self.
§Examples
Basic usage:
assert_eq!(isize::MAX.count_zeros(), 1);1.0.0 (const: 1.32.0) · Source
Returns the number of leading zeros in the binary representation of self.
Depending on what you’re doing with the value, you might also be interested in theilog2 function which returns a consistent number, even if the type widens.
§Examples
Basic usage:
let n = -1isize;
assert_eq!(n.leading_zeros(), 0);1.0.0 (const: 1.32.0) · Source
Returns the number of trailing zeros in the binary representation of self.
§Examples
Basic usage:
let n = -4isize;
assert_eq!(n.trailing_zeros(), 2);1.46.0 (const: 1.46.0) · Source
Returns the number of leading ones in the binary representation of self.
§Examples
Basic usage:
let n = -1isize;
assert_eq!(n.leading_ones(), 64);1.46.0 (const: 1.46.0) · Source
Returns the number of trailing ones in the binary representation of self.
§Examples
Basic usage:
let n = 3isize;
assert_eq!(n.trailing_ones(), 2);🔬This is a nightly-only experimental API. (integer_sign_cast #125882)
Returns the bit pattern of self reinterpreted as an unsigned integer of the same size.
This produces the same result as an as cast, but ensures that the bit-width remains the same.
§Examples
Basic usage:
#![feature(integer_sign_cast)]
let n = -1isize;
assert_eq!(n.cast_unsigned(), usize::MAX);1.0.0 (const: 1.32.0) · Source
Shifts 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 = 0xaa00000000006e1isize;
let m = 0x6e10aa;
assert_eq!(n.rotate_left(12), m);1.0.0 (const: 1.32.0) · Source
Shifts 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 = 0x6e10aaisize;
let m = 0xaa00000000006e1;
assert_eq!(n.rotate_right(12), m);1.0.0 (const: 1.32.0) · Source
Reverses the byte order of the integer.
§Examples
Basic usage:
let n = 0x1234567890123456isize;
let m = n.swap_bytes();
assert_eq!(m, 0x5634129078563412);1.37.0 (const: 1.37.0) · Source
Reverses 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 = 0x1234567890123456isize;
let m = n.reverse_bits();
assert_eq!(m, 0x6a2c48091e6a2c48);
assert_eq!(0, 0isize.reverse_bits());1.0.0 (const: 1.32.0) · Source
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
Basic usage:
let n = 0x1Aisize;
if cfg!(target_endian = "big") {
assert_eq!(isize::from_be(n), n)
} else {
assert_eq!(isize::from_be(n), n.swap_bytes())
}1.0.0 (const: 1.32.0) · Source
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
Basic usage:
let n = 0x1Aisize;
if cfg!(target_endian = "little") {
assert_eq!(isize::from_le(n), n)
} else {
assert_eq!(isize::from_le(n), n.swap_bytes())
}1.0.0 (const: 1.32.0) · Source
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
Basic usage:
let n = 0x1Aisize;
if cfg!(target_endian = "big") {
assert_eq!(n.to_be(), n)
} else {
assert_eq!(n.to_be(), n.swap_bytes())
}1.0.0 (const: 1.32.0) · Source
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
Basic usage:
let n = 0x1Aisize;
if cfg!(target_endian = "little") {
assert_eq!(n.to_le(), n)
} else {
assert_eq!(n.to_le(), n.swap_bytes())
}1.0.0 (const: 1.47.0) · Source
Checked integer addition. Computes self + rhs, returning Noneif overflow occurred.
§Examples
Basic usage:
assert_eq!((isize::MAX - 2).checked_add(1), Some(isize::MAX - 1));
assert_eq!((isize::MAX - 2).checked_add(3), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict integer addition. Computes self + rhs, panicking if overflow occurred.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!((isize::MAX - 2).strict_add(1), isize::MAX - 1);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = (isize::MAX - 2).strict_add(3);1.79.0 (const: 1.79.0) · Source
Unchecked integer addition. Computes self + rhs, assuming overflow cannot occur.
Calling x.unchecked_add(y) is semantically equivalent to callingx.checked_add(y).unwrap_unchecked().
If you’re just trying to avoid the panic in debug mode, then do notuse this. Instead, you’re looking for wrapping_add.
§Safety
This results in undefined behavior whenself + rhs > isize::MAX or self + rhs < isize::MIN, i.e. when checked_add would return None.
1.66.0 (const: 1.66.0) · Source
Checked addition with an unsigned integer. Computes self + rhs, returning None if overflow occurred.
§Examples
Basic usage:
assert_eq!(1isize.checked_add_unsigned(2), Some(3));
assert_eq!((isize::MAX - 2).checked_add_unsigned(3), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict addition with an unsigned integer. Computes self + rhs, panicking if overflow occurred.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(1isize.strict_add_unsigned(2), 3);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = (isize::MAX - 2).strict_add_unsigned(3);1.0.0 (const: 1.47.0) · Source
Checked integer subtraction. Computes self - rhs, returning None if overflow occurred.
§Examples
Basic usage:
assert_eq!((isize::MIN + 2).checked_sub(1), Some(isize::MIN + 1));
assert_eq!((isize::MIN + 2).checked_sub(3), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict integer subtraction. Computes self - rhs, panicking if overflow occurred.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!((isize::MIN + 2).strict_sub(1), isize::MIN + 1);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = (isize::MIN + 2).strict_sub(3);1.79.0 (const: 1.79.0) · Source
Unchecked integer subtraction. Computes self - rhs, assuming overflow cannot occur.
Calling x.unchecked_sub(y) is semantically equivalent to callingx.checked_sub(y).unwrap_unchecked().
If you’re just trying to avoid the panic in debug mode, then do notuse this. Instead, you’re looking for wrapping_sub.
§Safety
This results in undefined behavior whenself - rhs > isize::MAX or self - rhs < isize::MIN, i.e. when checked_sub would return None.
1.66.0 (const: 1.66.0) · Source
Checked subtraction with an unsigned integer. Computes self - rhs, returning None if overflow occurred.
§Examples
Basic usage:
assert_eq!(1isize.checked_sub_unsigned(2), Some(-1));
assert_eq!((isize::MIN + 2).checked_sub_unsigned(3), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict subtraction with an unsigned integer. Computes self - rhs, panicking if overflow occurred.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(1isize.strict_sub_unsigned(2), -1);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = (isize::MIN + 2).strict_sub_unsigned(3);1.0.0 (const: 1.47.0) · Source
Checked integer multiplication. Computes self * rhs, returning None if overflow occurred.
§Examples
Basic usage:
assert_eq!(isize::MAX.checked_mul(1), Some(isize::MAX));
assert_eq!(isize::MAX.checked_mul(2), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict integer multiplication. Computes self * rhs, panicking if overflow occurred.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(isize::MAX.strict_mul(1), isize::MAX);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = isize::MAX.strict_mul(2);1.79.0 (const: 1.79.0) · Source
Unchecked integer multiplication. Computes self * rhs, assuming overflow cannot occur.
Calling x.unchecked_mul(y) is semantically equivalent to callingx.checked_mul(y).unwrap_unchecked().
If you’re just trying to avoid the panic in debug mode, then do notuse this. Instead, you’re looking for wrapping_mul.
§Safety
This results in undefined behavior whenself * rhs > isize::MAX or self * rhs < isize::MIN, i.e. when checked_mul would return None.
1.0.0 (const: 1.52.0) · Source
Checked integer division. Computes self / rhs, returning None if rhs == 0or the division results in overflow.
§Examples
Basic usage:
assert_eq!((isize::MIN + 1).checked_div(-1), Some(9223372036854775807));
assert_eq!(isize::MIN.checked_div(-1), None);
assert_eq!((1isize).checked_div(0), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict integer division. Computes self / rhs, panicking if overflow occurred.
§Panics
This function will panic if rhs is zero.
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
The only case where such an overflow can occur is when one divides MIN / -1 on a signed type (whereMIN 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.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!((isize::MIN + 1).strict_div(-1), 9223372036854775807);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = isize::MIN.strict_div(-1);The following panics because of division by zero:
#![feature(strict_overflow_ops)]
let _ = (1isize).strict_div(0);1.38.0 (const: 1.52.0) · Source
Checked Euclidean division. Computes self.div_euclid(rhs), returning None if rhs == 0 or the division results in overflow.
§Examples
Basic usage:
assert_eq!((isize::MIN + 1).checked_div_euclid(-1), Some(9223372036854775807));
assert_eq!(isize::MIN.checked_div_euclid(-1), None);
assert_eq!((1isize).checked_div_euclid(0), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict Euclidean division. Computes self.div_euclid(rhs), panicking if overflow occurred.
§Panics
This function will panic if rhs is zero.
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
The only case where such an overflow can occur is when one divides MIN / -1 on a signed type (whereMIN 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.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!((isize::MIN + 1).strict_div_euclid(-1), 9223372036854775807);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = isize::MIN.strict_div_euclid(-1);The following panics because of division by zero:
#![feature(strict_overflow_ops)]
let _ = (1isize).strict_div_euclid(0);1.7.0 (const: 1.52.0) · Source
Checked integer remainder. Computes self % rhs, returning None ifrhs == 0 or the division results in overflow.
§Examples
Basic usage:
assert_eq!(5isize.checked_rem(2), Some(1));
assert_eq!(5isize.checked_rem(0), None);
assert_eq!(isize::MIN.checked_rem(-1), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict integer remainder. Computes self % rhs, panicking if the division results in overflow.
§Panics
This function will panic if rhs is zero.
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
The only case where such an overflow can occur is x % y for MIN / -1 on a signed type (where MIN is the negative minimal value), which is invalid due to implementation artifacts.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(5isize.strict_rem(2), 1);The following panics because of division by zero:
#![feature(strict_overflow_ops)]
let _ = 5isize.strict_rem(0);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = isize::MIN.strict_rem(-1);1.38.0 (const: 1.52.0) · Source
Checked Euclidean remainder. Computes self.rem_euclid(rhs), returning Noneif rhs == 0 or the division results in overflow.
§Examples
Basic usage:
assert_eq!(5isize.checked_rem_euclid(2), Some(1));
assert_eq!(5isize.checked_rem_euclid(0), None);
assert_eq!(isize::MIN.checked_rem_euclid(-1), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict Euclidean remainder. Computes self.rem_euclid(rhs), panicking if the division results in overflow.
§Panics
This function will panic if rhs is zero.
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
The only case where such an overflow can occur is x % y for MIN / -1 on a signed type (where MIN is the negative minimal value), which is invalid due to implementation artifacts.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(5isize.strict_rem_euclid(2), 1);The following panics because of division by zero:
#![feature(strict_overflow_ops)]
let _ = 5isize.strict_rem_euclid(0);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = isize::MIN.strict_rem_euclid(-1);1.7.0 (const: 1.47.0) · Source
Checked negation. Computes -self, returning None if self == MIN.
§Examples
Basic usage:
assert_eq!(5isize.checked_neg(), Some(-5));
assert_eq!(isize::MIN.checked_neg(), None);🔬This is a nightly-only experimental API. (unchecked_neg #85122)
Unchecked negation. Computes -self, assuming overflow cannot occur.
§Safety
This results in undefined behavior whenself == isize::MIN, i.e. when checked_neg would return None.
🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict negation. Computes -self, panicking if self == MIN.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(5isize.strict_neg(), -5);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = isize::MIN.strict_neg();1.7.0 (const: 1.47.0) · Source
Checked shift left. Computes self << rhs, returning None if rhs is larger than or equal to the number of bits in self.
§Examples
Basic usage:
assert_eq!(0x1isize.checked_shl(4), Some(0x10));
assert_eq!(0x1isize.checked_shl(129), None);
assert_eq!(0x10isize.checked_shl(63), Some(0));🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict shift left. Computes self << rhs, panicking if rhs is larger than or equal to the number of bits in self.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(0x1isize.strict_shl(4), 0x10);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = 0x1isize.strict_shl(129);🔬This is a nightly-only experimental API. (unchecked_shifts #85122)
Unchecked shift left. Computes self << rhs, assuming thatrhs 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. (unbounded_shifts #129375)
Unbounded shift left. Computes self << rhs, without bounding the value of rhs.
If rhs is larger or equal to the number of bits in self, the entire value is shifted out, and 0 is returned.
§Examples
Basic usage:
#![feature(unbounded_shifts)]
assert_eq!(0x1isize.unbounded_shl(4), 0x10);
assert_eq!(0x1isize.unbounded_shl(129), 0);1.7.0 (const: 1.47.0) · Source
Checked shift right. Computes self >> rhs, returning None if rhs is larger than or equal to the number of bits in self.
§Examples
Basic usage:
assert_eq!(0x10isize.checked_shr(4), Some(0x1));
assert_eq!(0x10isize.checked_shr(128), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict shift right. Computes self >> rhs, panicking rhs is larger than or equal to the number of bits in self.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(0x10isize.strict_shr(4), 0x1);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = 0x10isize.strict_shr(128);🔬This is a nightly-only experimental API. (unchecked_shifts #85122)
Unchecked shift right. Computes self >> rhs, assuming thatrhs 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.
🔬This is a nightly-only experimental API. (unbounded_shifts #129375)
Unbounded shift right. Computes self >> rhs, without bounding the value of rhs.
If rhs is larger or equal to the number of bits in self, the entire value is shifted out, which yields 0 for a positive number, and -1 for a negative number.
§Examples
Basic usage:
#![feature(unbounded_shifts)]
assert_eq!(0x10isize.unbounded_shr(4), 0x1);
assert_eq!(0x10isize.unbounded_shr(129), 0);
assert_eq!(isize::MIN.unbounded_shr(129), -1);1.13.0 (const: 1.47.0) · Source
Checked absolute value. Computes self.abs(), returning None ifself == MIN.
§Examples
Basic usage:
assert_eq!((-5isize).checked_abs(), Some(5));
assert_eq!(isize::MIN.checked_abs(), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict absolute value. Computes self.abs(), panicking ifself == MIN.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!((-5isize).strict_abs(), 5);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = isize::MIN.strict_abs();1.34.0 (const: 1.50.0) · Source
Checked exponentiation. Computes self.pow(exp), returning None if overflow occurred.
§Examples
Basic usage:
assert_eq!(8isize.checked_pow(2), Some(64));
assert_eq!(isize::MAX.checked_pow(2), None);🔬This is a nightly-only experimental API. (strict_overflow_ops #118260)
Strict exponentiation. Computes self.pow(exp), panicking if overflow occurred.
§Panics
§Overflow behavior
This function will always panic on overflow, regardless of whether overflow checks are enabled.
§Examples
Basic usage:
#![feature(strict_overflow_ops)]
assert_eq!(8isize.strict_pow(2), 64);The following panics because of overflow:
#![feature(strict_overflow_ops)]
let _ = isize::MAX.strict_pow(2);1.84.0 (const: 1.84.0) · Source
Returns the square root of the number, rounded down.
Returns None if self is negative.
§Examples
Basic usage:
assert_eq!(10isize.checked_isqrt(), Some(3));1.0.0 (const: 1.47.0) · Source
Saturating integer addition. Computes self + rhs, saturating at the numeric bounds instead of overflowing.
§Examples
Basic usage:
assert_eq!(100isize.saturating_add(1), 101);
assert_eq!(isize::MAX.saturating_add(100), isize::MAX);
assert_eq!(isize::MIN.saturating_add(-1), isize::MIN);1.66.0 (const: 1.66.0) · Source
Saturating addition with an unsigned integer. Computes self + rhs, saturating at the numeric bounds instead of overflowing.
§Examples
Basic usage:
assert_eq!(1isize.saturating_add_unsigned(2), 3);
assert_eq!(isize::MAX.saturating_add_unsigned(100), isize::MAX);1.0.0 (const: 1.47.0) · Source
Saturating integer subtraction. Computes self - rhs, saturating at the numeric bounds instead of overflowing.
§Examples
Basic usage:
assert_eq!(100isize.saturating_sub(127), -27);
assert_eq!(isize::MIN.saturating_sub(100), isize::MIN);
assert_eq!(isize::MAX.saturating_sub(-1), isize::MAX);1.66.0 (const: 1.66.0) · Source
Saturating subtraction with an unsigned integer. Computes self - rhs, saturating at the numeric bounds instead of overflowing.
§Examples
Basic usage:
assert_eq!(100isize.saturating_sub_unsigned(127), -27);
assert_eq!(isize::MIN.saturating_sub_unsigned(100), isize::MIN);1.45.0 (const: 1.47.0) · Source
Saturating integer negation. Computes -self, returning MAX if self == MINinstead of overflowing.
§Examples
Basic usage:
assert_eq!(100isize.saturating_neg(), -100);
assert_eq!((-100isize).saturating_neg(), 100);
assert_eq!(isize::MIN.saturating_neg(), isize::MAX);
assert_eq!(isize::MAX.saturating_neg(), isize::MIN + 1);1.45.0 (const: 1.47.0) · Source
Saturating absolute value. Computes self.abs(), returning MAX if self == MIN instead of overflowing.
§Examples
Basic usage:
assert_eq!(100isize.saturating_abs(), 100);
assert_eq!((-100isize).saturating_abs(), 100);
assert_eq!(isize::MIN.saturating_abs(), isize::MAX);
assert_eq!((isize::MIN + 1).saturating_abs(), isize::MAX);1.7.0 (const: 1.47.0) · Source
Saturating integer multiplication. Computes self * rhs, saturating at the numeric bounds instead of overflowing.
§Examples
Basic usage:
assert_eq!(10isize.saturating_mul(12), 120);
assert_eq!(isize::MAX.saturating_mul(10), isize::MAX);
assert_eq!(isize::MIN.saturating_mul(10), isize::MIN);1.58.0 (const: 1.58.0) · Source
Saturating integer division. Computes self / rhs, saturating at the numeric bounds instead of overflowing.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(5isize.saturating_div(2), 2);
assert_eq!(isize::MAX.saturating_div(-1), isize::MIN + 1);
assert_eq!(isize::MIN.saturating_div(-1), isize::MAX);
1.34.0 (const: 1.50.0) · Source
Saturating integer exponentiation. Computes self.pow(exp), saturating at the numeric bounds instead of overflowing.
§Examples
Basic usage:
assert_eq!((-4isize).saturating_pow(3), -64);
assert_eq!(isize::MIN.saturating_pow(2), isize::MAX);
assert_eq!(isize::MIN.saturating_pow(3), isize::MIN);1.0.0 (const: 1.32.0) · Source
Wrapping (modular) addition. Computes self + rhs, wrapping around at the boundary of the type.
§Examples
Basic usage:
assert_eq!(100isize.wrapping_add(27), 127);
assert_eq!(isize::MAX.wrapping_add(2), isize::MIN + 1);1.66.0 (const: 1.66.0) · Source
Wrapping (modular) addition with an unsigned integer. Computesself + rhs, wrapping around at the boundary of the type.
§Examples
Basic usage:
assert_eq!(100isize.wrapping_add_unsigned(27), 127);
assert_eq!(isize::MAX.wrapping_add_unsigned(2), isize::MIN + 1);1.0.0 (const: 1.32.0) · Source
Wrapping (modular) subtraction. Computes self - rhs, wrapping around at the boundary of the type.
§Examples
Basic usage:
assert_eq!(0isize.wrapping_sub(127), -127);
assert_eq!((-2isize).wrapping_sub(isize::MAX), isize::MAX);1.66.0 (const: 1.66.0) · Source
Wrapping (modular) subtraction with an unsigned integer. Computesself - rhs, wrapping around at the boundary of the type.
§Examples
Basic usage:
assert_eq!(0isize.wrapping_sub_unsigned(127), -127);
assert_eq!((-2isize).wrapping_sub_unsigned(usize::MAX), -1);1.0.0 (const: 1.32.0) · Source
Wrapping (modular) multiplication. Computes self * rhs, wrapping around at the boundary of the type.
§Examples
Basic usage:
assert_eq!(10isize.wrapping_mul(12), 120);
assert_eq!(11i8.wrapping_mul(12), -124);1.2.0 (const: 1.52.0) · Source
Wrapping (modular) division. Computes self / rhs, 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 (whereMIN 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.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(100isize.wrapping_div(10), 10);
assert_eq!((-128i8).wrapping_div(-1), -128);1.38.0 (const: 1.52.0) · Source
Wrapping Euclidean division. Computes self.div_euclid(rhs), wrapping around at the boundary of the type.
Wrapping will only occur in 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 this case, this method returns MIN itself.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(100isize.wrapping_div_euclid(10), 10);
assert_eq!((-128i8).wrapping_div_euclid(-1), -128);1.2.0 (const: 1.52.0) · Source
Wrapping (modular) remainder. Computes self % rhs, wrapping around at the boundary of the type.
Such wrap-around never actually occurs mathematically; implementation artifacts make x % yinvalid for MIN / -1 on a signed type (where MIN is the negative minimal value). In such a case, this function returns 0.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(100isize.wrapping_rem(10), 0);
assert_eq!((-128i8).wrapping_rem(-1), 0);1.38.0 (const: 1.52.0) · Source
Wrapping Euclidean remainder. Computes self.rem_euclid(rhs), wrapping around at the boundary of the type.
Wrapping will only occur in MIN % -1 on a signed type (where MIN is the negative minimal value for the type). In this case, this method returns 0.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(100isize.wrapping_rem_euclid(10), 0);
assert_eq!((-128i8).wrapping_rem_euclid(-1), 0);1.2.0 (const: 1.32.0) · Source
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 MINis 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.
§Examples
Basic usage:
assert_eq!(100isize.wrapping_neg(), -100);
assert_eq!((-100isize).wrapping_neg(), 100);
assert_eq!(isize::MIN.wrapping_neg(), isize::MIN);1.2.0 (const: 1.32.0) · Source
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.
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!((-1isize).wrapping_shl(7), -128);
assert_eq!((-1isize).wrapping_shl(128), -1);1.2.0 (const: 1.32.0) · Source
Panic-free bitwise shift-right; yields self >> mask(rhs), where maskremoves 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!((-128isize).wrapping_shr(7), -1);
assert_eq!((-128i16).wrapping_shr(64), -128);1.13.0 (const: 1.32.0) · Source
Wrapping (modular) absolute value. Computes self.abs(), wrapping around at the boundary of the type.
The only case where such wrapping can occur is when one takes the absolute value of 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.
§Examples
Basic usage:
assert_eq!(100isize.wrapping_abs(), 100);
assert_eq!((-100isize).wrapping_abs(), 100);
assert_eq!(isize::MIN.wrapping_abs(), isize::MIN);
assert_eq!((-128i8).wrapping_abs() as u8, 128);1.51.0 (const: 1.51.0) · Source
Computes the absolute value of self without any wrapping or panicking.
§Examples
Basic usage:
assert_eq!(100isize.unsigned_abs(), 100usize);
assert_eq!((-100isize).unsigned_abs(), 100usize);
assert_eq!((-128i8).unsigned_abs(), 128u8);1.34.0 (const: 1.50.0) · Source
Wrapping (modular) exponentiation. Computes self.pow(exp), wrapping around at the boundary of the type.
§Examples
Basic usage:
assert_eq!(3isize.wrapping_pow(4), 81);
assert_eq!(3i8.wrapping_pow(5), -13);
assert_eq!(3i8.wrapping_pow(6), -39);1.7.0 (const: 1.32.0) · Source
Calculates 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!(5isize.overflowing_add(2), (7, false));
assert_eq!(isize::MAX.overflowing_add(1), (isize::MIN, true));🔬This is a nightly-only experimental API. (bigint_helper_methods #85532)
Calculates self + rhs + carry and checks for overflow.
Performs “ternary addition” of two integer operands and a carry-in bit, and returns a tuple of the sum along with a boolean indicating whether an arithmetic overflow would occur. On overflow, the wrapped value is returned.
This allows chaining together multiple additions to create a wider addition, and can be useful for bignum addition. This method should only be used for the most significant word; for the less significant words the unsigned methodusize::carrying_addshould be used.
The output boolean returned by this method is not a carry flag, and should not be added to a more significant word.
If the input carry is false, this method is equivalent tooverflowing_add.
§Examples
#![feature(bigint_helper_methods)]
// Only the most significant word is signed.
//
// 10 MAX (a = 10 × 2^64 + 2^64 - 1)
// + -5 9 (b = -5 × 2^64 + 9)
// ---------
// 6 8 (sum = 6 × 2^64 + 8)
let (a1, a0): (isize, usize) = (10, usize::MAX);
let (b1, b0): (isize, usize) = (-5, 9);
let carry0 = false;
// usize::carrying_add for the less significant words
let (sum0, carry1) = a0.carrying_add(b0, carry0);
assert_eq!(carry1, true);
// isize::carrying_add for the most significant word
let (sum1, overflow) = a1.carrying_add(b1, carry1);
assert_eq!(overflow, false);
assert_eq!((sum1, sum0), (6, 8));1.66.0 (const: 1.66.0) · Source
Calculates self + rhs with an unsigned 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!(1isize.overflowing_add_unsigned(2), (3, false));
assert_eq!((isize::MIN).overflowing_add_unsigned(usize::MAX), (isize::MAX, false));
assert_eq!((isize::MAX - 2).overflowing_add_unsigned(3), (isize::MIN, true));1.7.0 (const: 1.32.0) · Source
Calculates 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!(5isize.overflowing_sub(2), (3, false));
assert_eq!(isize::MIN.overflowing_sub(1), (isize::MAX, true));🔬This is a nightly-only experimental API. (bigint_helper_methods #85532)
Calculates self − rhs − borrow and checks for overflow.
Performs “ternary subtraction” by subtracting both an integer operand and a borrow-in bit from self, and returns a tuple of the difference along with a boolean indicating whether an arithmetic overflow would occur. On overflow, the wrapped value is returned.
This allows chaining together multiple subtractions to create a wider subtraction, and can be useful for bignum subtraction. This method should only be used for the most significant word; for the less significant words the unsigned methodusize::borrowing_subshould be used.
The output boolean returned by this method is not a borrow flag, and should not be subtracted from a more significant word.
If the input borrow is false, this method is equivalent tooverflowing_sub.
§Examples
#![feature(bigint_helper_methods)]
// Only the most significant word is signed.
//
// 6 8 (a = 6 × 2^64 + 8)
// - -5 9 (b = -5 × 2^64 + 9)
// ---------
// 10 MAX (diff = 10 × 2^64 + 2^64 - 1)
let (a1, a0): (isize, usize) = (6, 8);
let (b1, b0): (isize, usize) = (-5, 9);
let borrow0 = false;
// usize::borrowing_sub for the less significant words
let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
assert_eq!(borrow1, true);
// isize::borrowing_sub for the most significant word
let (diff1, overflow) = a1.borrowing_sub(b1, borrow1);
assert_eq!(overflow, false);
assert_eq!((diff1, diff0), (10, usize::MAX));1.66.0 (const: 1.66.0) · Source
Calculates self - rhs with an unsigned 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!(1isize.overflowing_sub_unsigned(2), (-1, false));
assert_eq!((isize::MAX).overflowing_sub_unsigned(usize::MAX), (isize::MIN, false));
assert_eq!((isize::MIN + 2).overflowing_sub_unsigned(3), (isize::MAX, true));1.7.0 (const: 1.32.0) · Source
Calculates 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:
assert_eq!(5isize.overflowing_mul(2), (10, false));
assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));🔬This is a nightly-only experimental API. (bigint_helper_methods #85532)
Calculates the complete product self * rhs without the possibility to overflow.
This returns the low-order (wrapping) bits and the high-order (overflow) bits of the result as two separate values, in that order.
If you also need to add a carry to the wide result, then you wantSelf::carrying_mul instead.
§Examples
Basic usage:
Please note that this example is shared between integer types. Which explains why i32 is used here.
#![feature(bigint_helper_methods)]
assert_eq!(5i32.widening_mul(-2), (4294967286, -1));
assert_eq!(1_000_000_000i32.widening_mul(-10), (2884901888, -3));🔬This is a nightly-only experimental API. (bigint_helper_methods #85532)
Calculates the “full multiplication” self * rhs + carrywithout the possibility to overflow.
This returns the low-order (wrapping) bits and the high-order (overflow) bits of the result as two separate values, in that order.
Performs “long multiplication” which takes in an extra amount to add, and may return an additional amount of overflow. This allows for chaining together multiple multiplications to create “big integers” which represent larger values.
If you don’t need the carry, then you can use Self::widening_mul instead.
§Examples
Basic usage:
Please note that this example is shared between integer types. Which explains why i32 is used here.
#![feature(bigint_helper_methods)]
assert_eq!(5i32.carrying_mul(-2, 0), (4294967286, -1));
assert_eq!(5i32.carrying_mul(-2, 10), (0, 0));
assert_eq!(1_000_000_000i32.carrying_mul(-10, 0), (2884901888, -3));
assert_eq!(1_000_000_000i32.carrying_mul(-10, 10), (2884901898, -3));
assert_eq!(isize::MAX.carrying_mul(isize::MAX, isize::MAX), (isize::MAX.unsigned_abs() + 1, isize::MAX / 2));🔬This is a nightly-only experimental API. (bigint_helper_methods #85532)
Calculates the “full multiplication” self * rhs + carry1 + carry2without the possibility to overflow.
This returns the low-order (wrapping) bits and the high-order (overflow) bits of the result as two separate values, in that order.
Performs “long multiplication” which takes in an extra amount to add, and may return an additional amount of overflow. This allows for chaining together multiple multiplications to create “big integers” which represent larger values.
If you don’t need either carry, then you can use Self::widening_mul instead, and if you only need one carry, then you can use Self::carrying_mul instead.
§Examples
Basic usage:
Please note that this example is shared between integer types. Which explains why i32 is used here.
#![feature(bigint_helper_methods)]
assert_eq!(5i32.carrying_mul_add(-2, 0, 0), (4294967286, -1));
assert_eq!(5i32.carrying_mul_add(-2, 10, 10), (10, 0));
assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 0, 0), (2884901888, -3));
assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 10, 10), (2884901908, -3));
assert_eq!(isize::MAX.carrying_mul_add(isize::MAX, isize::MAX, isize::MAX), (usize::MAX, isize::MAX / 2));1.7.0 (const: 1.52.0) · Source
Calculates 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. If an overflow would occur then self is returned.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(5isize.overflowing_div(2), (2, false));
assert_eq!(isize::MIN.overflowing_div(-1), (isize::MIN, true));1.38.0 (const: 1.52.0) · Source
Calculates 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. If an overflow would occur then self is returned.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(5isize.overflowing_div_euclid(2), (2, false));
assert_eq!(isize::MIN.overflowing_div_euclid(-1), (isize::MIN, true));1.7.0 (const: 1.52.0) · Source
Calculates 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. If an overflow would occur then 0 is returned.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(5isize.overflowing_rem(2), (1, false));
assert_eq!(isize::MIN.overflowing_rem(-1), (0, true));1.38.0 (const: 1.52.0) · Source
Overflowing Euclidean remainder. Calculates self.rem_euclid(rhs).
Returns a tuple of the remainder after dividing along with a boolean indicating whether an arithmetic overflow would occur. If an overflow would occur then 0 is returned.
§Panics
This function will panic if rhs is zero.
§Examples
Basic usage:
assert_eq!(5isize.overflowing_rem_euclid(2), (1, false));
assert_eq!(isize::MIN.overflowing_rem_euclid(-1), (0, true));1.7.0 (const: 1.32.0) · Source
Negates self, overflowing if this is equal to the minimum value.
Returns a tuple of the negated version of self along with a boolean indicating whether an overflow happened. If self is the minimum value (e.g., i32::MIN for values of type i32), then the minimum value will be returned again and true will be returned for an overflow happening.
§Examples
Basic usage:
assert_eq!(2isize.overflowing_neg(), (-2, false));
assert_eq!(isize::MIN.overflowing_neg(), (isize::MIN, true));1.7.0 (const: 1.32.0) · Source
Shifts 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!(0x1isize.overflowing_shl(4), (0x10, false));
assert_eq!(0x1i32.overflowing_shl(36), (0x10, true));
assert_eq!(0x10isize.overflowing_shl(63), (0, false));1.7.0 (const: 1.32.0) · Source
Shifts 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!(0x10isize.overflowing_shr(4), (0x1, false));
assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));1.13.0 (const: 1.32.0) · Source
Computes the absolute value of self.
Returns a tuple of the absolute version of self along with a boolean indicating whether an overflow happened. If self is the minimum value (e.g., isize::MIN for values of type isize), then the minimum value will be returned again and true will be returned for an overflow happening.
§Examples
Basic usage:
assert_eq!(10isize.overflowing_abs(), (10, false));
assert_eq!((-10isize).overflowing_abs(), (10, false));
assert_eq!((isize::MIN).overflowing_abs(), (isize::MIN, true));1.34.0 (const: 1.50.0) · Source
Raises self to the power of exp, using exponentiation by squaring.
Returns a tuple of the exponentiation along with a bool indicating whether an overflow happened.
§Examples
Basic usage:
assert_eq!(3isize.overflowing_pow(4), (81, false));
assert_eq!(3i8.overflowing_pow(5), (-13, true));1.0.0 (const: 1.50.0) · Source
Raises self to the power of exp, using exponentiation by squaring.
§Examples
Basic usage:
let x: isize = 2; // or any other integer type
assert_eq!(x.pow(5), 32);1.84.0 (const: 1.84.0) · Source
Returns the square root of the number, rounded down.
§Panics
This function will panic if self is negative.
§Examples
Basic usage:
assert_eq!(10isize.isqrt(), 3);1.38.0 (const: 1.52.0) · Source
Calculates the quotient of Euclidean division of self by rhs.
This computes the integer q such that self = q * rhs + r, withr = self.rem_euclid(rhs) and 0 <= r < abs(rhs).
In other words, the result is self / rhs rounded to the integer qsuch that self >= q * rhs. If self > 0, this is equal to rounding towards zero (the default in Rust); if self < 0, this is equal to rounding away from zero (towards +/- infinity). If rhs > 0, this is equal to rounding towards -infinity; if rhs < 0, this is equal to rounding towards +infinity.
§Panics
This function will panic if rhs is zero or if self is Self::MINand rhs is -1. This behavior is not affected by the overflow-checks flag.
§Examples
Basic usage:
let a: isize = 7; // or any other integer type
let b = 4;
assert_eq!(a.div_euclid(b), 1); // 7 >= 4 * 1
assert_eq!(a.div_euclid(-b), -1); // 7 >= -4 * -1
assert_eq!((-a).div_euclid(b), -2); // -7 >= 4 * -2
assert_eq!((-a).div_euclid(-b), 2); // -7 >= -4 * 21.38.0 (const: 1.52.0) · Source
Calculates the least nonnegative remainder of self (mod rhs).
This is done as if by the Euclidean division algorithm – givenr = self.rem_euclid(rhs), the result satisfiesself = rhs * self.div_euclid(rhs) + r and 0 <= r < abs(rhs).
§Panics
This function will panic if rhs is zero or if self is Self::MIN andrhs is -1. This behavior is not affected by the overflow-checks flag.
§Examples
Basic usage:
let a: isize = 7; // or any other integer type
let b = 4;
assert_eq!(a.rem_euclid(b), 3);
assert_eq!((-a).rem_euclid(b), 1);
assert_eq!(a.rem_euclid(-b), 3);
assert_eq!((-a).rem_euclid(-b), 1);This will panic:
let _ = isize::MIN.rem_euclid(-1);🔬This is a nightly-only experimental API. (int_roundings #88581)
Calculates the quotient of self and rhs, rounding the result towards negative infinity.
§Panics
This function will panic if rhs is zero or if self is Self::MINand rhs is -1. This behavior is not affected by the overflow-checks flag.
§Examples
Basic usage:
#![feature(int_roundings)]
let a: isize = 8;
let b = 3;
assert_eq!(a.div_floor(b), 2);
assert_eq!(a.div_floor(-b), -3);
assert_eq!((-a).div_floor(b), -3);
assert_eq!((-a).div_floor(-b), 2);🔬This is a nightly-only experimental API. (int_roundings #88581)
Calculates the quotient of self and rhs, rounding the result towards positive infinity.
§Panics
This function will panic if rhs is zero or if self is Self::MINand rhs is -1. This behavior is not affected by the overflow-checks flag.
§Examples
Basic usage:
#![feature(int_roundings)]
let a: isize = 8;
let b = 3;
assert_eq!(a.div_ceil(b), 3);
assert_eq!(a.div_ceil(-b), -2);
assert_eq!((-a).div_ceil(b), -2);
assert_eq!((-a).div_ceil(-b), 3);🔬This is a nightly-only experimental API. (int_roundings #88581)
If rhs is positive, calculates the smallest value greater than or equal to self that is a multiple of rhs. If rhs is negative, calculates the largest value less than or equal to self that is a multiple of rhs.
§Panics
This function will panic if rhs is zero.
§Overflow behavior
On overflow, this function will panic if overflow checks are enabled (default in debug mode) and wrap if overflow checks are disabled (default in release mode).
§Examples
Basic usage:
#![feature(int_roundings)]
assert_eq!(16_isize.next_multiple_of(8), 16);
assert_eq!(23_isize.next_multiple_of(8), 24);
assert_eq!(16_isize.next_multiple_of(-8), 16);
assert_eq!(23_isize.next_multiple_of(-8), 16);
assert_eq!((-16_isize).next_multiple_of(8), -16);
assert_eq!((-23_isize).next_multiple_of(8), -16);
assert_eq!((-16_isize).next_multiple_of(-8), -16);
assert_eq!((-23_isize).next_multiple_of(-8), -24);🔬This is a nightly-only experimental API. (int_roundings #88581)
If rhs is positive, calculates the smallest value greater than or equal to self that is a multiple of rhs. If rhs is negative, calculates the largest value less than or equal to self that is a multiple of rhs. Returns None if rhs is zero or the operation would result in overflow.
§Examples
Basic usage:
#![feature(int_roundings)]
assert_eq!(16_isize.checked_next_multiple_of(8), Some(16));
assert_eq!(23_isize.checked_next_multiple_of(8), Some(24));
assert_eq!(16_isize.checked_next_multiple_of(-8), Some(16));
assert_eq!(23_isize.checked_next_multiple_of(-8), Some(16));
assert_eq!((-16_isize).checked_next_multiple_of(8), Some(-16));
assert_eq!((-23_isize).checked_next_multiple_of(8), Some(-16));
assert_eq!((-16_isize).checked_next_multiple_of(-8), Some(-16));
assert_eq!((-23_isize).checked_next_multiple_of(-8), Some(-24));
assert_eq!(1_isize.checked_next_multiple_of(0), None);
assert_eq!(isize::MAX.checked_next_multiple_of(2), None);1.67.0 (const: 1.67.0) · Source
Returns the logarithm of the number with respect to an arbitrary base, rounded down.
This method might not be optimized owing to implementation details;ilog2 can produce results more efficiently for base 2, and ilog10can produce results more efficiently for base 10.
§Panics
This function will panic if self is less than or equal to zero, or if base is less than 2.
§Examples
assert_eq!(5isize.ilog(5), 1);1.67.0 (const: 1.67.0) · Source
Returns the base 2 logarithm of the number, rounded down.
§Panics
This function will panic if self is less than or equal to zero.
§Examples
assert_eq!(2isize.ilog2(), 1);1.67.0 (const: 1.67.0) · Source
Returns the base 10 logarithm of the number, rounded down.
§Panics
This function will panic if self is less than or equal to zero.
§Example
assert_eq!(10isize.ilog10(), 1);1.67.0 (const: 1.67.0) · Source
Returns the logarithm of the number with respect to an arbitrary base, rounded down.
Returns None if the number is negative or zero, or if the base is not at least 2.
This method might not be optimized owing to implementation details;checked_ilog2 can produce results more efficiently for base 2, andchecked_ilog10 can produce results more efficiently for base 10.
§Examples
assert_eq!(5isize.checked_ilog(5), Some(1));1.67.0 (const: 1.67.0) · Source
Returns the base 2 logarithm of the number, rounded down.
Returns None if the number is negative or zero.
§Examples
assert_eq!(2isize.checked_ilog2(), Some(1));1.67.0 (const: 1.67.0) · Source
Returns the base 10 logarithm of the number, rounded down.
Returns None if the number is negative or zero.
§Example
assert_eq!(10isize.checked_ilog10(), Some(1));1.0.0 (const: 1.32.0) · Source
Computes the absolute value of self.
§Overflow behavior
The absolute value ofisize::MINcannot be represented as anisize, and attempting to calculate it will cause an overflow. This means that code in debug mode will trigger a panic on this case and optimized code will returnisize::MINwithout a panic. If you do not want this behavior, consider using unsigned_abs instead.
§Examples
Basic usage:
assert_eq!(10isize.abs(), 10);
assert_eq!((-10isize).abs(), 10);1.60.0 (const: 1.60.0) · Source
Computes the absolute difference between self and other.
This function always returns the correct answer without overflow or panics by returning an unsigned integer.
§Examples
Basic usage:
assert_eq!(100isize.abs_diff(80), 20usize);
assert_eq!(100isize.abs_diff(110), 10usize);
assert_eq!((-100isize).abs_diff(80), 180usize);
assert_eq!((-100isize).abs_diff(-120), 20usize);
assert_eq!(isize::MIN.abs_diff(isize::MAX), usize::MAX);1.0.0 (const: 1.47.0) · Source
Returns a number representing sign of self.
0if the number is zero1if the number is positive-1if the number is negative
§Examples
Basic usage:
assert_eq!(10isize.signum(), 1);
assert_eq!(0isize.signum(), 0);
assert_eq!((-10isize).signum(), -1);1.0.0 (const: 1.32.0) · Source
Returns true if self is positive and false if the number is zero or negative.
§Examples
Basic usage:
assert!(10isize.is_positive());
assert!(!(-10isize).is_positive());1.0.0 (const: 1.32.0) · Source
Returns true if self is negative and false if the number is zero or positive.
§Examples
Basic usage:
assert!((-10isize).is_negative());
assert!(!10isize.is_negative());1.32.0 (const: 1.44.0) · Source
Returns the memory representation of this integer as a byte array in big-endian (network) byte order.
Note: This function returns an array of length 2, 4 or 8 bytes depending on the target pointer size.
§Examples
let bytes = 0x1234567890123456isize.to_be_bytes();
assert_eq!(bytes, [0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]);1.32.0 (const: 1.44.0) · Source
Returns the memory representation of this integer as a byte array in little-endian byte order.
Note: This function returns an array of length 2, 4 or 8 bytes depending on the target pointer size.
§Examples
let bytes = 0x1234567890123456isize.to_le_bytes();
assert_eq!(bytes, [0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]);1.32.0 (const: 1.44.0) · Source
Returns 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.
Note: This function returns an array of length 2, 4 or 8 bytes depending on the target pointer size.
§Examples
let bytes = 0x1234567890123456isize.to_ne_bytes();
assert_eq!(
bytes,
if cfg!(target_endian = "big") {
[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]
} else {
[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]
}
);1.32.0 (const: 1.44.0) · Source
Creates an integer value from its representation as a byte array in big endian.
Note: This function takes an array of length 2, 4 or 8 bytes depending on the target pointer size.
§Examples
let value = isize::from_be_bytes([0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]);
assert_eq!(value, 0x1234567890123456);When starting from a slice rather than an array, fallible conversion APIs can be used:
fn read_be_isize(input: &mut &[u8]) -> isize {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<isize>());
*input = rest;
isize::from_be_bytes(int_bytes.try_into().unwrap())
}1.32.0 (const: 1.44.0) · Source
Creates an integer value from its representation as a byte array in little endian.
Note: This function takes an array of length 2, 4 or 8 bytes depending on the target pointer size.
§Examples
let value = isize::from_le_bytes([0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]);
assert_eq!(value, 0x1234567890123456);When starting from a slice rather than an array, fallible conversion APIs can be used:
fn read_le_isize(input: &mut &[u8]) -> isize {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<isize>());
*input = rest;
isize::from_le_bytes(int_bytes.try_into().unwrap())
}1.32.0 (const: 1.44.0) · Source
Creates an 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.
Note: This function takes an array of length 2, 4 or 8 bytes depending on the target pointer size.
§Examples
let value = isize::from_ne_bytes(if cfg!(target_endian = "big") {
[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]
} else {
[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]
});
assert_eq!(value, 0x1234567890123456);When starting from a slice rather than an array, fallible conversion APIs can be used:
fn read_ne_isize(input: &mut &[u8]) -> isize {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<isize>());
*input = rest;
isize::from_ne_bytes(int_bytes.try_into().unwrap())
}1.0.0 (const: 1.32.0) · Source
👎Deprecating in a future version: replaced by the MIN associated constant on this type
New code should prefer to useisize::MIN instead.
Returns the smallest value that can be represented by this integer type.
1.0.0 (const: 1.32.0) · Source
👎Deprecating in a future version: replaced by the MAX associated constant on this type
New code should prefer to useisize::MAX instead.
Returns the largest value that can be represented by this integer type.
🔬This is a nightly-only experimental API. (num_midpoint_signed #110840)
Calculates the middle point of self and rhs.
midpoint(a, b) is (a + b) / 2 as if it were performed in a sufficiently-large signed integral type. This implies that the result is always rounded towards zero and that no overflow will ever occur.
§Examples
#![feature(num_midpoint_signed)]
assert_eq!(0isize.midpoint(4), 2);
assert_eq!((-1isize).midpoint(2), 0);
assert_eq!((-7isize).midpoint(0), -3);
assert_eq!(0isize.midpoint(-7), -3);
assert_eq!(0isize.midpoint(7), 3);1.0.0 (const: 1.82.0) · Source
Parses an integer from a string slice with digits in a given base.
The string is expected to be an optional+ or -sign followed by only digits. Leading and trailing non-digit characters (including whitespace) represent an error. Underscores (which are accepted in Rust literals) also represent an error.
Digits are a subset of these characters, depending on radix:
0-9a-zA-Z
§Panics
This function panics if radix is not in the range from 2 to 36.
§Examples
Basic usage:
assert_eq!(isize::from_str_radix("A", 16), Ok(10));Trailing space returns error:
assert!(isize::from_str_radix("1 ", 10).is_err());🔬This is a nightly-only experimental API. (int_from_ascii #134821)
Parses an integer from an ASCII-byte slice with decimal digits.
The characters are expected to be an optional+ or -sign followed by only digits. Leading and trailing non-digit characters (including whitespace) represent an error. Underscores (which are accepted in Rust literals) also represent an error.
§Examples
Basic usage:
#![feature(int_from_ascii)]
assert_eq!(isize::from_ascii(b"+10"), Ok(10));Trailing space returns error:
assert!(isize::from_ascii(b"1 ").is_err());🔬This is a nightly-only experimental API. (int_from_ascii #134821)
Parses an integer from an ASCII-byte slice with digits in a given base.
The characters are expected to be an optional+ or -sign followed by only digits. Leading and trailing non-digit characters (including whitespace) represent an error. Underscores (which are accepted in Rust literals) also represent an error.
Digits are a subset of these characters, depending on radix:
0-9a-zA-Z
§Panics
This function panics if radix is not in the range from 2 to 36.
§Examples
Basic usage:
#![feature(int_from_ascii)]
assert_eq!(isize::from_ascii_radix(b"A", 16), Ok(10));Trailing space returns error:
assert!(isize::from_ascii_radix(b"1 ", 10).is_err());