i8 - Rust
source link: https://doc.rust-lang.org/stable/std/primitive.i8.html
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Implementations
The smallest value that can be represented by this integer type, -27.
Examples
Basic usage:
assert_eq!(i8::MIN, -128);
RunThe largest value that can be represented by this integer type, 27 - 1.
Examples
Basic usage:
assert_eq!(i8::MAX, 127);
RunConverts a string slice in a given base to an integer.
The string is expected to be an optional +
or -
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!(i8::from_str_radix("A", 16), Ok(10));
Runpub const fn count_ones(self) -> u32
Returns the number of ones in the binary representation of self
.
Examples
Basic usage:
let n = 0b100_0000i8;
assert_eq!(n.count_ones(), 1);
Runpub const fn count_zeros(self) -> u32
Returns the number of zeros in the binary representation of self
.
Examples
Basic usage:
assert_eq!(i8::MAX.count_zeros(), 1);
Runpub const fn leading_zeros(self) -> u32
Returns the number of leading zeros in the binary representation of self
.
Examples
Basic usage:
let n = -1i8;
assert_eq!(n.leading_zeros(), 0);
Runpub const fn trailing_zeros(self) -> u32
Returns the number of trailing zeros in the binary representation of self
.
Examples
Basic usage:
let n = -4i8;
assert_eq!(n.trailing_zeros(), 2);
Runpub const fn leading_ones(self) -> u32
Returns the number of leading ones in the binary representation of self
.
Examples
Basic usage:
let n = -1i8;
assert_eq!(n.leading_ones(), 8);
Runpub const fn trailing_ones(self) -> u32
Returns the number of trailing ones in the binary representation of self
.
Examples
Basic usage:
let n = 3i8;
assert_eq!(n.trailing_ones(), 2);
Runpub const fn rotate_left(self, n: u32) -> i8
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 = -0x7ei8;
let m = 0xa;
assert_eq!(n.rotate_left(2), m);
Runpub const fn rotate_right(self, n: u32) -> i8
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 = 0xai8;
let m = -0x7e;
assert_eq!(n.rotate_right(2), m);
Runpub const fn swap_bytes(self) -> i8
Reverses the byte order of the integer.
Examples
Basic usage:
let n = 0x12i8;
let m = n.swap_bytes();
assert_eq!(m, 0x12);
Runpub const fn reverse_bits(self) -> i8
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 = 0x12i8;
let m = n.reverse_bits();
assert_eq!(m, 0x48);
assert_eq!(0, 0i8.reverse_bits());
RunConverts 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 = 0x1Ai8;
if cfg!(target_endian = "big") {
assert_eq!(i8::from_be(n), n)
} else {
assert_eq!(i8::from_be(n), n.swap_bytes())
}
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 = 0x1Ai8;
if cfg!(target_endian = "little") {
assert_eq!(i8::from_le(n), n)
} else {
assert_eq!(i8::from_le(n), n.swap_bytes())
}
RunConverts 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 = 0x1Ai8;
if cfg!(target_endian = "big") {
assert_eq!(n.to_be(), n)
} else {
assert_eq!(n.to_be(), n.swap_bytes())
}
RunConverts 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 = 0x1Ai8;
if cfg!(target_endian = "little") {
assert_eq!(n.to_le(), n)
} else {
assert_eq!(n.to_le(), n.swap_bytes())
}
Runpub const fn checked_add(self, rhs: i8) -> Option<i8>
Checked integer addition. Computes self + rhs
, returning None
if overflow occurred.
Examples
Basic usage:
assert_eq!((i8::MAX - 2).checked_add(1), Some(i8::MAX - 1));
assert_eq!((i8::MAX - 2).checked_add(3), None);
Runpub unsafe fn unchecked_add(self, rhs: i8) -> i8
unchecked_math
#85122)Unchecked integer addition. Computes self + rhs
, assuming overflow
cannot occur.
Safety
This results in undefined behavior when
self + rhs > i8::MAX
or self + rhs < i8::MIN
,
i.e. when checked_add
would return None
.
mixed_integer_ops
#87840)Checked addition with an unsigned integer. Computes self + rhs
,
returning None
if overflow occurred.
Examples
Basic usage:
assert_eq!(1i8.checked_add_unsigned(2), Some(3));
assert_eq!((i8::MAX - 2).checked_add_unsigned(3), None);
Runpub const fn checked_sub(self, rhs: i8) -> Option<i8>
Checked integer subtraction. Computes self - rhs
, returning None
if
overflow occurred.
Examples
Basic usage:
assert_eq!((i8::MIN + 2).checked_sub(1), Some(i8::MIN + 1));
assert_eq!((i8::MIN + 2).checked_sub(3), None);
Runpub unsafe fn unchecked_sub(self, rhs: i8) -> i8
unchecked_math
#85122)Unchecked integer subtraction. Computes self - rhs
, assuming overflow
cannot occur.
Safety
This results in undefined behavior when
self - rhs > i8::MAX
or self - rhs < i8::MIN
,
i.e. when checked_sub
would return None
.
mixed_integer_ops
#87840)Checked subtraction with an unsigned integer. Computes self - rhs
,
returning None
if overflow occurred.
Examples
Basic usage:
assert_eq!(1i8.checked_sub_unsigned(2), Some(-1));
assert_eq!((i8::MIN + 2).checked_sub_unsigned(3), None);
Runpub const fn checked_mul(self, rhs: i8) -> Option<i8>
Checked integer multiplication. Computes self * rhs
, returning None
if
overflow occurred.
Examples
Basic usage:
assert_eq!(i8::MAX.checked_mul(1), Some(i8::MAX));
assert_eq!(i8::MAX.checked_mul(2), None);
Runpub unsafe fn unchecked_mul(self, rhs: i8) -> i8
unchecked_math
#85122)Unchecked integer multiplication. Computes self * rhs
, assuming overflow
cannot occur.
Safety
This results in undefined behavior when
self * rhs > i8::MAX
or self * rhs < i8::MIN
,
i.e. when checked_mul
would return None
.
pub const fn checked_div(self, rhs: i8) -> Option<i8>
Checked integer division. Computes self / rhs
, returning None
if rhs == 0
or the division results in overflow.
Examples
Basic usage:
assert_eq!((i8::MIN + 1).checked_div(-1), Some(127));
assert_eq!(i8::MIN.checked_div(-1), None);
assert_eq!((1i8).checked_div(0), None);
Runpub const fn checked_div_euclid(self, rhs: i8) -> Option<i8>
Checked Euclidean division. Computes self.div_euclid(rhs)
,
returning None
if rhs == 0
or the division results in overflow.
Examples
Basic usage:
assert_eq!((i8::MIN + 1).checked_div_euclid(-1), Some(127));
assert_eq!(i8::MIN.checked_div_euclid(-1), None);
assert_eq!((1i8).checked_div_euclid(0), None);
Runpub const fn checked_rem(self, rhs: i8) -> Option<i8>
Checked integer remainder. Computes self % rhs
, returning None
if
rhs == 0
or the division results in overflow.
Examples
Basic usage:
assert_eq!(5i8.checked_rem(2), Some(1));
assert_eq!(5i8.checked_rem(0), None);
assert_eq!(i8::MIN.checked_rem(-1), None);
Runpub const fn checked_rem_euclid(self, rhs: i8) -> Option<i8>
Checked Euclidean remainder. Computes self.rem_euclid(rhs)
, returning None
if rhs == 0
or the division results in overflow.
Examples
Basic usage:
assert_eq!(5i8.checked_rem_euclid(2), Some(1));
assert_eq!(5i8.checked_rem_euclid(0), None);
assert_eq!(i8::MIN.checked_rem_euclid(-1), None);
Runpub const fn checked_neg(self) -> Option<i8>
Checked negation. Computes -self
, returning None
if self == MIN
.
Examples
Basic usage:
assert_eq!(5i8.checked_neg(), Some(-5));
assert_eq!(i8::MIN.checked_neg(), None);
Runpub const fn checked_shl(self, rhs: u32) -> Option<i8>
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!(0x1i8.checked_shl(4), Some(0x10));
assert_eq!(0x1i8.checked_shl(129), None);
Runpub unsafe fn unchecked_shl(self, rhs: i8) -> i8
unchecked_math
#85122)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
.
pub const fn checked_shr(self, rhs: u32) -> Option<i8>
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!(0x10i8.checked_shr(4), Some(0x1));
assert_eq!(0x10i8.checked_shr(128), None);
Runpub unsafe fn unchecked_shr(self, rhs: i8) -> i8
unchecked_math
#85122)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
.
pub const fn checked_abs(self) -> Option<i8>
Checked absolute value. Computes self.abs()
, returning None
if
self == MIN
.
Examples
Basic usage:
assert_eq!((-5i8).checked_abs(), Some(5));
assert_eq!(i8::MIN.checked_abs(), None);
Runpub const fn checked_pow(self, exp: u32) -> Option<i8>
Checked exponentiation. Computes self.pow(exp)
, returning None
if
overflow occurred.
Examples
Basic usage:
assert_eq!(8i8.checked_pow(2), Some(64));
assert_eq!(i8::MAX.checked_pow(2), None);
Runpub const fn saturating_add(self, rhs: i8) -> i8
Saturating integer addition. Computes self + rhs
, saturating at the numeric
bounds instead of overflowing.
Examples
Basic usage:
assert_eq!(100i8.saturating_add(1), 101);
assert_eq!(i8::MAX.saturating_add(100), i8::MAX);
assert_eq!(i8::MIN.saturating_add(-1), i8::MIN);
Runmixed_integer_ops
#87840)Saturating addition with an unsigned integer. Computes self + rhs
,
saturating at the numeric bounds instead of overflowing.
Examples
Basic usage:
assert_eq!(1i8.saturating_add_unsigned(2), 3);
assert_eq!(i8::MAX.saturating_add_unsigned(100), i8::MAX);
Runpub const fn saturating_sub(self, rhs: i8) -> i8
Saturating integer subtraction. Computes self - rhs
, saturating at the
numeric bounds instead of overflowing.
Examples
Basic usage:
assert_eq!(100i8.saturating_sub(127), -27);
assert_eq!(i8::MIN.saturating_sub(100), i8::MIN);
assert_eq!(i8::MAX.saturating_sub(-1), i8::MAX);
Runmixed_integer_ops
#87840)Saturating subtraction with an unsigned integer. Computes self - rhs
,
saturating at the numeric bounds instead of overflowing.
Examples
Basic usage:
assert_eq!(100i8.saturating_sub_unsigned(127), -27);
assert_eq!(i8::MIN.saturating_sub_unsigned(100), i8::MIN);
Runpub const fn saturating_neg(self) -> i8
Saturating integer negation. Computes -self
, returning MAX
if self == MIN
instead of overflowing.
Examples
Basic usage:
assert_eq!(100i8.saturating_neg(), -100);
assert_eq!((-100i8).saturating_neg(), 100);
assert_eq!(i8::MIN.saturating_neg(), i8::MAX);
assert_eq!(i8::MAX.saturating_neg(), i8::MIN + 1);
Runpub const fn saturating_abs(self) -> i8
Saturating absolute value. Computes self.abs()
, returning MAX
if self == MIN
instead of overflowing.
Examples
Basic usage:
assert_eq!(100i8.saturating_abs(), 100);
assert_eq!((-100i8).saturating_abs(), 100);
assert_eq!(i8::MIN.saturating_abs(), i8::MAX);
assert_eq!((i8::MIN + 1).saturating_abs(), i8::MAX);
Runpub const fn saturating_mul(self, rhs: i8) -> i8
Saturating integer multiplication. Computes self * rhs
, saturating at the
numeric bounds instead of overflowing.
Examples
Basic usage:
assert_eq!(10i8.saturating_mul(12), 120);
assert_eq!(i8::MAX.saturating_mul(10), i8::MAX);
assert_eq!(i8::MIN.saturating_mul(10), i8::MIN);
Runpub const fn saturating_div(self, rhs: i8) -> i8
Saturating integer division. Computes self / rhs
, saturating at the
numeric bounds instead of overflowing.
Examples
Basic usage:
assert_eq!(5i8.saturating_div(2), 2);
assert_eq!(i8::MAX.saturating_div(-1), i8::MIN + 1);
assert_eq!(i8::MIN.saturating_div(-1), i8::MAX);
Runlet _ = 1i8.saturating_div(0);
Runpub const fn saturating_pow(self, exp: u32) -> i8
Saturating integer exponentiation. Computes self.pow(exp)
,
saturating at the numeric bounds instead of overflowing.
Examples
Basic usage:
assert_eq!((-4i8).saturating_pow(3), -64);
assert_eq!(i8::MIN.saturating_pow(2), i8::MAX);
assert_eq!(i8::MIN.saturating_pow(3), i8::MIN);
Runpub const fn wrapping_add(self, rhs: i8) -> i8
Wrapping (modular) addition. Computes self + rhs
, wrapping around at the
boundary of the type.
Examples
Basic usage:
assert_eq!(100i8.wrapping_add(27), 127);
assert_eq!(i8::MAX.wrapping_add(2), i8::MIN + 1);
Runmixed_integer_ops
#87840)Wrapping (modular) addition with an unsigned integer. Computes
self + rhs
, wrapping around at the boundary of the type.
Examples
Basic usage:
assert_eq!(100i8.wrapping_add_unsigned(27), 127);
assert_eq!(i8::MAX.wrapping_add_unsigned(2), i8::MIN + 1);
Runpub const fn wrapping_sub(self, rhs: i8) -> i8
Wrapping (modular) subtraction. Computes self - rhs
, wrapping around at the
boundary of the type.
Examples
Basic usage:
assert_eq!(0i8.wrapping_sub(127), -127);
assert_eq!((-2i8).wrapping_sub(i8::MAX), i8::MAX);
Runmixed_integer_ops
#87840)Wrapping (modular) subtraction with an unsigned integer. Computes
self - rhs
, wrapping around at the boundary of the type.
Examples
Basic usage:
assert_eq!(0i8.wrapping_sub_unsigned(127), -127);
assert_eq!((-2i8).wrapping_sub_unsigned(u8::MAX), -1);
Runpub const fn wrapping_mul(self, rhs: i8) -> i8
Wrapping (modular) multiplication. Computes self * rhs
, wrapping around at
the boundary of the type.
Examples
Basic usage:
assert_eq!(10i8.wrapping_mul(12), 120);
assert_eq!(11i8.wrapping_mul(12), -124);
Runpub const fn wrapping_div(self, rhs: i8) -> i8
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 (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.
Panics
This function will panic if rhs
is 0.
Examples
Basic usage:
assert_eq!(100i8.wrapping_div(10), 10);
assert_eq!((-128i8).wrapping_div(-1), -128);
Runpub const fn wrapping_div_euclid(self, rhs: i8) -> i8
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 0.
Examples
Basic usage:
assert_eq!(100i8.wrapping_div_euclid(10), 10);
assert_eq!((-128i8).wrapping_div_euclid(-1), -128);
Runpub const fn wrapping_rem(self, rhs: i8) -> i8
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 % y
invalid 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 0.
Examples
Basic usage:
assert_eq!(100i8.wrapping_rem(10), 0);
assert_eq!((-128i8).wrapping_rem(-1), 0);
Runpub const fn wrapping_rem_euclid(self, rhs: i8) -> i8
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 0.
Examples
Basic usage:
assert_eq!(100i8.wrapping_rem_euclid(10), 0);
assert_eq!((-128i8).wrapping_rem_euclid(-1), 0);
Runpub const fn wrapping_neg(self) -> i8
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.
Examples
Basic usage:
assert_eq!(100i8.wrapping_neg(), -100);
assert_eq!(i8::MIN.wrapping_neg(), i8::MIN);
Runpub const fn wrapping_shl(self, rhs: u32) -> i8
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!((-1i8).wrapping_shl(7), -128);
assert_eq!((-1i8).wrapping_shl(128), -1);
Runpub const fn wrapping_shr(self, rhs: u32) -> i8
Panic-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!((-128i8).wrapping_shr(7), -1);
assert_eq!((-128i16).wrapping_shr(64), -128);
Runpub const fn wrapping_abs(self) -> i8
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!(100i8.wrapping_abs(), 100);
assert_eq!((-100i8).wrapping_abs(), 100);
assert_eq!(i8::MIN.wrapping_abs(), i8::MIN);
assert_eq!((-128i8).wrapping_abs() as u8, 128);
Runpub const fn unsigned_abs(self) -> u8
Computes the absolute value of self
without any wrapping
or panicking.
Examples
Basic usage:
assert_eq!(100i8.unsigned_abs(), 100u8);
assert_eq!((-100i8).unsigned_abs(), 100u8);
assert_eq!((-128i8).unsigned_abs(), 128u8);
Runpub const fn wrapping_pow(self, exp: u32) -> i8
Wrapping (modular) exponentiation. Computes self.pow(exp)
,
wrapping around at the boundary of the type.
Examples
Basic usage:
assert_eq!(3i8.wrapping_pow(4), 81);
assert_eq!(3i8.wrapping_pow(5), -13);
assert_eq!(3i8.wrapping_pow(6), -39);
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!(5i8.overflowing_add(2), (7, false));
assert_eq!(i8::MAX.overflowing_add(1), (i8::MIN, true));
Runmixed_integer_ops
#87840)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!(1i8.overflowing_add_unsigned(2), (3, false));
assert_eq!((i8::MIN).overflowing_add_unsigned(u8::MAX), (i8::MAX, false));
assert_eq!((i8::MAX - 2).overflowing_add_unsigned(3), (i8::MIN, 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!(5i8.overflowing_sub(2), (3, false));
assert_eq!(i8::MIN.overflowing_sub(1), (i8::MAX, true));
Runmixed_integer_ops
#87840)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!(1i8.overflowing_sub_unsigned(2), (-1, false));
assert_eq!((i8::MAX).overflowing_sub_unsigned(u8::MAX), (i8::MIN, false));
assert_eq!((i8::MIN + 2).overflowing_sub_unsigned(3), (i8::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:
assert_eq!(5i8.overflowing_mul(2), (10, false));
assert_eq!(1_000_000_000i32.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. If an overflow would occur then self is returned.
Panics
This function will panic if rhs
is 0.
Examples
Basic usage:
assert_eq!(5i8.overflowing_div(2), (2, false));
assert_eq!(i8::MIN.overflowing_div(-1), (i8::MIN, true));
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. If an overflow would occur then self
is returned.
Panics
This function will panic if rhs
is 0.
Examples
Basic usage:
assert_eq!(5i8.overflowing_div_euclid(2), (2, false));
assert_eq!(i8::MIN.overflowing_div_euclid(-1), (i8::MIN, true));
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. If an overflow would occur then 0 is returned.
Panics
This function will panic if rhs
is 0.
Examples
Basic usage:
assert_eq!(5i8.overflowing_rem(2), (1, false));
assert_eq!(i8::MIN.overflowing_rem(-1), (0, true));
RunOverflowing 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 0.
Examples
Basic usage:
assert_eq!(5i8.overflowing_rem_euclid(2), (1, false));
assert_eq!(i8::MIN.overflowing_rem_euclid(-1), (0, true));
Runpub const fn overflowing_neg(self) -> (i8, bool)
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!(2i8.overflowing_neg(), (-2, false));
assert_eq!(i8::MIN.overflowing_neg(), (i8::MIN, 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!(0x1i8.overflowing_shl(4), (0x10, false));
assert_eq!(0x1i32.overflowing_shl(36), (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!(0x10i8.overflowing_shr(4), (0x1, false));
assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
Runpub const fn overflowing_abs(self) -> (i8, bool)
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., i8::MIN for values of type i8), then the minimum value will be returned again and true will be returned for an overflow happening.
Examples
Basic usage:
assert_eq!(10i8.overflowing_abs(), (10, false));
assert_eq!((-10i8).overflowing_abs(), (10, false));
assert_eq!((i8::MIN).overflowing_abs(), (i8::MIN, true));
RunRaises 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!(3i8.overflowing_pow(4), (81, false));
assert_eq!(3i8.overflowing_pow(5), (-13, true));
RunRaises self to the power of exp
, using exponentiation by squaring.
Examples
Basic usage:
let x: i8 = 2; // or any other integer type
assert_eq!(x.pow(5), 32);
Runpub const fn div_euclid(self, rhs: i8) -> i8
Calculates the quotient of Euclidean division of self
by rhs
.
This computes the integer q
such that self = q * rhs + r
, with
r = self.rem_euclid(rhs)
and 0 <= r < abs(rhs)
.
In other words, the result is self / rhs
rounded to the integer q
such that self >= q * rhs
.
If self > 0
, this is equal to round towards zero (the default in Rust);
if self < 0
, this is equal to round towards +/- infinity.
Panics
This function will panic if rhs
is 0 or the division results in overflow.
Examples
Basic usage:
let a: i8 = 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 * 2
Runpub const fn rem_euclid(self, rhs: i8) -> i8
Calculates the least nonnegative remainder of self (mod rhs)
.
This is done as if by the Euclidean division algorithm – given
r = self.rem_euclid(rhs)
, self = rhs * self.div_euclid(rhs) + r
, and
0 <= r < abs(rhs)
.
Panics
This function will panic if rhs
is 0 or the division results in overflow.
Examples
Basic usage:
let a: i8 = 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);
Runint_roundings
#88581)Calculates the quotient of self
and rhs
, rounding the result towards negative infinity.
Panics
This function will panic if rhs
is 0 or the division results in overflow.
Examples
Basic usage:
#![feature(int_roundings)]
let a: i8 = 8;
let b = 3;
assert_eq!(a.unstable_div_floor(b), 2);
assert_eq!(a.unstable_div_floor(-b), -3);
assert_eq!((-a).unstable_div_floor(b), -3);
assert_eq!((-a).unstable_div_floor(-b), 2);
Runint_roundings
#88581)Calculates the quotient of self
and rhs
, rounding the result towards positive infinity.
Panics
This function will panic if rhs
is 0 or the division results in overflow.
Examples
Basic usage:
#![feature(int_roundings)]
let a: i8 = 8;
let b = 3;
assert_eq!(a.unstable_div_ceil(b), 3);
assert_eq!(a.unstable_div_ceil(-b), -2);
assert_eq!((-a).unstable_div_ceil(b), -2);
assert_eq!((-a).unstable_div_ceil(-b), 3);
Runint_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 0 or the operation results in overflow.
Examples
Basic usage:
#![feature(int_roundings)]
assert_eq!(16_i8.unstable_next_multiple_of(8), 16);
assert_eq!(23_i8.unstable_next_multiple_of(8), 24);
assert_eq!(16_i8.unstable_next_multiple_of(-8), 16);
assert_eq!(23_i8.unstable_next_multiple_of(-8), 16);
assert_eq!((-16_i8).unstable_next_multiple_of(8), -16);
assert_eq!((-23_i8).unstable_next_multiple_of(8), -16);
assert_eq!((-16_i8).unstable_next_multiple_of(-8), -16);
assert_eq!((-23_i8).unstable_next_multiple_of(-8), -24);
Runint_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_i8.checked_next_multiple_of(8), Some(16));
assert_eq!(23_i8.checked_next_multiple_of(8), Some(24));
assert_eq!(16_i8.checked_next_multiple_of(-8), Some(16));
assert_eq!(23_i8.checked_next_multiple_of(-8), Some(16));
assert_eq!((-16_i8).checked_next_multiple_of(8), Some(-16));
assert_eq!((-23_i8).checked_next_multiple_of(8), Some(-16));
assert_eq!((-16_i8).checked_next_multiple_of(-8), Some(-16));
assert_eq!((-23_i8).checked_next_multiple_of(-8), Some(-24));
assert_eq!(1_i8.checked_next_multiple_of(0), None);
assert_eq!(i8::MAX.checked_next_multiple_of(2), None);
Runint_log
#70887)Returns the logarithm of the number with respect to an arbitrary base, rounded down.
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 zero, or if the base is not at least 2; it panics in debug mode and the return value is 0 in release mode.
Examples
#![feature(int_log)]
assert_eq!(5i8.log(5), 1);
Runint_log
#70887)Returns the base 2 logarithm of the number, rounded down.
Panics
When the number is zero it panics in debug mode and the return value is 0 in release mode.
Examples
#![feature(int_log)]
assert_eq!(2i8.log2(), 1);
Runint_log
#70887)Returns the base 10 logarithm of the number, rounded down.
Panics
When the number is zero it panics in debug mode and the return value is 0 in release mode.
Example
#![feature(int_log)]
assert_eq!(10i8.log10(), 1);
Runint_log
#70887)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_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!(5i8.checked_log(5), Some(1));
Runint_log
#70887)Returns the base 2 logarithm of the number, rounded down.
Returns None
if the number is negative or zero.
Examples
#![feature(int_log)]
assert_eq!(2i8.checked_log2(), Some(1));
Runint_log
#70887)Returns the base 10 logarithm of the number, rounded down.
Returns None
if the number is negative or zero.
Example
#![feature(int_log)]
assert_eq!(10i8.checked_log10(), Some(1));
RunComputes the absolute value of self
.
Overflow behavior
The absolute value of
i8::MIN
cannot be represented as an
i8
,
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 return
i8::MIN
without a panic.
Examples
Basic usage:
assert_eq!(10i8.abs(), 10);
assert_eq!((-10i8).abs(), 10);
Runint_abs_diff
#89492)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:
#![feature(int_abs_diff)]
assert_eq!(100i8.abs_diff(80), 20u8);
assert_eq!(100i8.abs_diff(110), 10u8);
assert_eq!((-100i8).abs_diff(80), 180u8);
assert_eq!((-100i8).abs_diff(-120), 20u8);
assert_eq!(i8::MIN.abs_diff(i8::MAX), u8::MAX);
RunReturns a number representing sign of self
.
0
if the number is zero1
if the number is positive-1
if the number is negative
Examples
Basic usage:
assert_eq!(10i8.signum(), 1);
assert_eq!(0i8.signum(), 0);
assert_eq!((-10i8).signum(), -1);
Runpub const fn is_positive(self) -> bool
Returns true
if self
is positive and false
if the number is zero or
negative.
Examples
Basic usage:
assert!(10i8.is_positive());
assert!(!(-10i8).is_positive());
Runpub const fn is_negative(self) -> bool
Returns true
if self
is negative and false
if the number is zero or
positive.
Examples
Basic usage:
assert!((-10i8).is_negative());
assert!(!10i8.is_negative());
Runpub const fn to_be_bytes(self) -> [u8; 1]
Return the memory representation of this integer as a byte array in big-endian (network) byte order.
Examples
let bytes = 0x12i8.to_be_bytes();
assert_eq!(bytes, [0x12]);
Runpub const fn to_le_bytes(self) -> [u8; 1]
Return the memory representation of this integer as a byte array in little-endian byte order.
Examples
let bytes = 0x12i8.to_le_bytes();
assert_eq!(bytes, [0x12]);
Runpub const fn to_ne_bytes(self) -> [u8; 1]
Return 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 = 0x12i8.to_ne_bytes();
assert_eq!(
bytes,
if cfg!(target_endian = "big") {
[0x12]
} else {
[0x12]
}
);
Runpub const fn from_be_bytes(bytes: [u8; 1]) -> i8
Create an integer value from its representation as a byte array in big endian.
Examples
let value = i8::from_be_bytes([0x12]);
assert_eq!(value, 0x12);
RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:
use std::convert::TryInto;
fn read_be_i8(input: &mut &[u8]) -> i8 {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<i8>());
*input = rest;
i8::from_be_bytes(int_bytes.try_into().unwrap())
}
Runpub const fn from_le_bytes(bytes: [u8; 1]) -> i8
Create an integer value from its representation as a byte array in little endian.
Examples
let value = i8::from_le_bytes([0x12]);
assert_eq!(value, 0x12);
RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:
use std::convert::TryInto;
fn read_le_i8(input: &mut &[u8]) -> i8 {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<i8>());
*input = rest;
i8::from_le_bytes(int_bytes.try_into().unwrap())
}
Runpub const fn from_ne_bytes(bytes: [u8; 1]) -> i8
Create 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.
Examples
let value = i8::from_ne_bytes(if cfg!(target_endian = "big") {
[0x12]
} else {
[0x12]
});
assert_eq!(value, 0x12);
RunWhen starting from a slice rather than an array, fallible conversion APIs can be used:
use std::convert::TryInto;
fn read_ne_i8(input: &mut &[u8]) -> i8 {
let (int_bytes, rest) = input.split_at(std::mem::size_of::<i8>());
*input = rest;
i8::from_ne_bytes(int_bytes.try_into().unwrap())
}
Runreplaced by the MIN
associated constant on this type
New code should prefer to use
i8::MIN
instead.
Returns the smallest value that can be represented by this integer type.
replaced by the MAX
associated constant on this type
New code should prefer to use
i8::MAX
instead.
Returns the largest value that can be represented by this integer type.
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