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rust/rust/fc5a7077ca43894de1ea0d3f9f56ac627ceef5c7/./library/core/src/num/uint_macros.rs
blob: 27dbe6d3f1d8b18a0e89b9ea3bde06ae55369950 [file]
macro_rules! uint_impl {
(
Self = $SelfT:ty,
ActualT = $ActualT:ident,
SignedT = $SignedT:ident,
// These are all for use *only* in doc comments.
// As such, they're all passed as literals -- passing them as a string
// literal is fine if they need to be multiple code tokens.
// In non-comments, use the associated constants rather than these.
BITS = $BITS:literal,
BITS_MINUS_ONE = $BITS_MINUS_ONE:literal,
MAX = $MaxV:literal,
rot = $rot:literal,
rot_op = $rot_op:literal,
rot_result = $rot_result:literal,
fsh_op = $fsh_op:literal,
fshl_result = $fshl_result:literal,
fshr_result = $fshr_result:literal,
clmul_lhs = $clmul_lhs:literal,
clmul_rhs = $clmul_rhs:literal,
clmul_result = $clmul_result:literal,
swap_op = $swap_op:literal,
swapped = $swapped:literal,
reversed = $reversed:literal,
le_bytes = $le_bytes:literal,
be_bytes = $be_bytes:literal,
to_xe_bytes_doc = $to_xe_bytes_doc:expr,
from_xe_bytes_doc = $from_xe_bytes_doc:expr,
bound_condition = $bound_condition:literal,
) => {
/// The smallest value that can be represented by this integer type.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, 0);")]
/// ```
#[stable(feature = "assoc_int_consts", since = "1.43.0")]
pub const MIN: Self = 0;
/// The largest value that can be represented by this integer type
#[doc = concat!("(2<sup>", $BITS, "</sup> &minus; 1", $bound_condition, ").")]
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");")]
/// ```
#[stable(feature = "assoc_int_consts", since = "1.43.0")]
pub const MAX: Self = !0;
/// The size of this integer type in bits.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
/// ```
#[stable(feature = "int_bits_const", since = "1.53.0")]
pub const BITS: u32 = Self::MAX.count_ones();
/// Returns the number of ones in the binary representation of `self`.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")]
/// assert_eq!(n.count_ones(), 3);
///
#[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
#[doc = concat!("assert_eq!(max.count_ones(), ", stringify!($BITS), ");")]
///
#[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
/// assert_eq!(zero.count_ones(), 0);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[doc(alias = "popcount")]
#[doc(alias = "popcnt")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn count_ones(self) -> u32 {
return intrinsics::ctpop(self);
}
/// Returns the number of zeros in the binary representation of `self`.
///
/// # Examples
///
/// ```
#[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
#[doc = concat!("assert_eq!(zero.count_zeros(), ", stringify!($BITS), ");")]
///
#[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
/// assert_eq!(max.count_zeros(), 0);
/// ```
///
/// This is heavily dependent on the width of the type, and thus
/// might give surprising results depending on type inference:
/// ```
/// # fn foo(_: u8) {}
/// # fn bar(_: u16) {}
/// let lucky = 7;
/// foo(lucky);
/// assert_eq!(lucky.count_zeros(), 5);
/// assert_eq!(lucky.count_ones(), 3);
///
/// let lucky = 7;
/// bar(lucky);
/// assert_eq!(lucky.count_zeros(), 13);
/// assert_eq!(lucky.count_ones(), 3);
/// ```
/// You might want to use [`Self::count_ones`] instead, or emphasize
/// the type you're using in the call rather than method syntax:
/// ```
/// let small = 1;
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::count_zeros(small), ", stringify!($BITS_MINUS_ONE) ,");")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn count_zeros(self) -> u32 {
(!self).count_ones()
}
/// 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 the
/// [`ilog2`] function which returns a consistent number, even if the type widens.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")]
/// assert_eq!(n.leading_zeros(), 2);
///
#[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
#[doc = concat!("assert_eq!(zero.leading_zeros(), ", stringify!($BITS), ");")]
///
#[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
/// assert_eq!(max.leading_zeros(), 0);
/// ```
#[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn leading_zeros(self) -> u32 {
return intrinsics::ctlz(self as $ActualT);
}
/// Returns the number of trailing zeros in the binary representation
/// of `self`.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")]
/// assert_eq!(n.trailing_zeros(), 3);
///
#[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
#[doc = concat!("assert_eq!(zero.trailing_zeros(), ", stringify!($BITS), ");")]
///
#[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
#[doc = concat!("assert_eq!(max.trailing_zeros(), 0);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn trailing_zeros(self) -> u32 {
return intrinsics::cttz(self);
}
/// Returns the number of leading ones in the binary representation of `self`.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")]
/// assert_eq!(n.leading_ones(), 2);
///
#[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
/// assert_eq!(zero.leading_ones(), 0);
///
#[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
#[doc = concat!("assert_eq!(max.leading_ones(), ", stringify!($BITS), ");")]
/// ```
#[stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn leading_ones(self) -> u32 {
(!self).leading_zeros()
}
/// Returns the number of trailing ones in the binary representation
/// of `self`.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")]
/// assert_eq!(n.trailing_ones(), 3);
///
#[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
/// assert_eq!(zero.trailing_ones(), 0);
///
#[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
#[doc = concat!("assert_eq!(max.trailing_ones(), ", stringify!($BITS), ");")]
/// ```
#[stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn trailing_ones(self) -> u32 {
(!self).trailing_zeros()
}
/// Returns the minimum number of bits required to represent `self`.
///
/// This method returns zero if `self` is zero.
///
/// # Examples
///
/// ```
/// #![feature(uint_bit_width)]
///
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".bit_width(), 0);")]
#[doc = concat!("assert_eq!(0b111_", stringify!($SelfT), ".bit_width(), 3);")]
#[doc = concat!("assert_eq!(0b1110_", stringify!($SelfT), ".bit_width(), 4);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.bit_width(), ", stringify!($BITS), ");")]
/// ```
#[unstable(feature = "uint_bit_width", issue = "142326")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn bit_width(self) -> u32 {
Self::BITS - self.leading_zeros()
}
/// Returns `self` with only the most significant bit set, or `0` if
/// the input is `0`.
///
/// # Examples
///
/// ```
/// #![feature(isolate_most_least_significant_one)]
///
#[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
///
/// assert_eq!(n.isolate_highest_one(), 0b_01000000);
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_highest_one(), 0);")]
/// ```
#[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn isolate_highest_one(self) -> Self {
self & (((1 as $SelfT) << (<$SelfT>::BITS - 1)).wrapping_shr(self.leading_zeros()))
}
/// Returns `self` with only the least significant bit set, or `0` if
/// the input is `0`.
///
/// # Examples
///
/// ```
/// #![feature(isolate_most_least_significant_one)]
///
#[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
///
/// assert_eq!(n.isolate_lowest_one(), 0b_00000100);
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_lowest_one(), 0);")]
/// ```
#[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn isolate_lowest_one(self) -> Self {
self & self.wrapping_neg()
}
/// Returns the index of the highest bit set to one in `self`, or `None`
/// if `self` is `0`.
///
/// # Examples
///
/// ```
/// #![feature(int_lowest_highest_one)]
///
#[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".highest_one(), None);")]
#[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".highest_one(), Some(0));")]
#[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".highest_one(), Some(4));")]
#[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".highest_one(), Some(4));")]
/// ```
#[unstable(feature = "int_lowest_highest_one", issue = "145203")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn highest_one(self) -> Option<u32> {
match NonZero::new(self) {
Some(v) => Some(v.highest_one()),
None => None,
}
}
/// Returns the index of the lowest bit set to one in `self`, or `None`
/// if `self` is `0`.
///
/// # Examples
///
/// ```
/// #![feature(int_lowest_highest_one)]
///
#[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".lowest_one(), None);")]
#[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
#[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".lowest_one(), Some(4));")]
#[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".lowest_one(), Some(0));")]
/// ```
#[unstable(feature = "int_lowest_highest_one", issue = "145203")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn lowest_one(self) -> Option<u32> {
match NonZero::new(self) {
Some(v) => Some(v.lowest_one()),
None => None,
}
}
/// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
///
/// This produces the same result as an `as` cast, but ensures that the bit-width remains
/// the same.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = ", stringify!($SelfT), "::MAX;")]
///
#[doc = concat!("assert_eq!(n.cast_signed(), -1", stringify!($SignedT), ");")]
/// ```
#[stable(feature = "integer_sign_cast", since = "1.87.0")]
#[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn cast_signed(self) -> $SignedT {
self as $SignedT
}
/// Shifts the bits to the left by a specified amount, `n`,
/// wrapping the truncated bits to the end of the resulting integer.
///
/// `rotate_left(n)` is equivalent to applying `rotate_left(1)` a total of `n` times. In
/// particular, a rotation by the number of bits in `self` returns the input value
/// unchanged.
///
/// Please note this isn't the same operation as the `<<` shifting operator!
///
/// # Examples
///
/// ```
#[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
#[doc = concat!("let m = ", $rot_result, ";")]
///
#[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
#[doc = concat!("assert_eq!(n.rotate_left(1024), n);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[rustc_allow_const_fn_unstable(const_trait_impl)] // for the intrinsic fallback
pub const fn rotate_left(self, n: u32) -> Self {
return intrinsics::rotate_left(self, n);
}
/// Shifts the bits to the right by a specified amount, `n`,
/// wrapping the truncated bits to the beginning of the resulting
/// integer.
///
/// `rotate_right(n)` is equivalent to applying `rotate_right(1)` a total of `n` times. In
/// particular, a rotation by the number of bits in `self` returns the input value
/// unchanged.
///
/// Please note this isn't the same operation as the `>>` shifting operator!
///
/// # Examples
///
/// ```
#[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
#[doc = concat!("let m = ", $rot_op, ";")]
///
#[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
#[doc = concat!("assert_eq!(n.rotate_right(1024), n);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[rustc_allow_const_fn_unstable(const_trait_impl)] // for the intrinsic fallback
pub const fn rotate_right(self, n: u32) -> Self {
return intrinsics::rotate_right(self, n);
}
/// Performs a left funnel shift (concatenates `self` with `rhs`, with `self`
/// making up the most significant half, then shifts the combined value left
/// by `n`, and most significant half is extracted to produce the result).
///
/// Please note this isn't the same operation as the `<<` shifting operator or
/// [`rotate_left`](Self::rotate_left), although `a.funnel_shl(a, n)` is *equivalent*
/// to `a.rotate_left(n)`.
///
/// # Panics
///
/// If `n` is greater than or equal to the number of bits in `self`
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// #![feature(funnel_shifts)]
#[doc = concat!("let a = ", $rot_op, stringify!($SelfT), ";")]
#[doc = concat!("let b = ", $fsh_op, stringify!($SelfT), ";")]
#[doc = concat!("let m = ", $fshl_result, ";")]
///
#[doc = concat!("assert_eq!(a.funnel_shl(b, ", $rot, "), m);")]
/// ```
#[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
#[unstable(feature = "funnel_shifts", issue = "145686")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn funnel_shl(self, rhs: Self, n: u32) -> Self {
assert!(n < Self::BITS, "attempt to funnel shift left with overflow");
// SAFETY: just checked that `shift` is in-range
unsafe { self.unchecked_funnel_shl(rhs, n) }
}
/// Performs a right funnel shift (concatenates `self` and `rhs`, with `self`
/// making up the most significant half, then shifts the combined value right
/// by `n`, and least significant half is extracted to produce the result).
///
/// Please note this isn't the same operation as the `>>` shifting operator or
/// [`rotate_right`](Self::rotate_right), although `a.funnel_shr(a, n)` is *equivalent*
/// to `a.rotate_right(n)`.
///
/// # Panics
///
/// If `n` is greater than or equal to the number of bits in `self`
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// #![feature(funnel_shifts)]
#[doc = concat!("let a = ", $rot_op, stringify!($SelfT), ";")]
#[doc = concat!("let b = ", $fsh_op, stringify!($SelfT), ";")]
#[doc = concat!("let m = ", $fshr_result, ";")]
///
#[doc = concat!("assert_eq!(a.funnel_shr(b, ", $rot, "), m);")]
/// ```
#[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
#[unstable(feature = "funnel_shifts", issue = "145686")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn funnel_shr(self, rhs: Self, n: u32) -> Self {
assert!(n < Self::BITS, "attempt to funnel shift right with overflow");
// SAFETY: just checked that `shift` is in-range
unsafe { self.unchecked_funnel_shr(rhs, n) }
}
/// Unchecked funnel shift left.
///
/// # Safety
///
/// This results in undefined behavior if `n` is greater than or equal to
#[doc = concat!("`", stringify!($SelfT) , "::BITS`,")]
/// i.e. when [`funnel_shl`](Self::funnel_shl) would panic.
///
#[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
#[unstable(feature = "funnel_shifts", issue = "145686")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const unsafe fn unchecked_funnel_shl(self, low: Self, n: u32) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_funnel_shl cannot overflow"),
(n: u32 = n) => n < <$ActualT>::BITS,
);
// SAFETY: this is guaranteed to be safe by the caller.
unsafe {
intrinsics::unchecked_funnel_shl(self, low, n)
}
}
/// Unchecked funnel shift right.
///
/// # Safety
///
/// This results in undefined behavior if `n` is greater than or equal to
#[doc = concat!("`", stringify!($SelfT) , "::BITS`,")]
/// i.e. when [`funnel_shr`](Self::funnel_shr) would panic.
///
#[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
#[unstable(feature = "funnel_shifts", issue = "145686")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const unsafe fn unchecked_funnel_shr(self, low: Self, n: u32) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_funnel_shr cannot overflow"),
(n: u32 = n) => n < <$ActualT>::BITS,
);
// SAFETY: this is guaranteed to be safe by the caller.
unsafe {
intrinsics::unchecked_funnel_shr(self, low, n)
}
}
/// Performs a carry-less multiplication, returning the lower bits.
///
/// This operation is similar to long multiplication in base 2, except that exclusive or is
/// used instead of addition. The implementation is equivalent to:
///
/// ```no_run
#[doc = concat!("pub fn carryless_mul(lhs: ", stringify!($SelfT), ", rhs: ", stringify!($SelfT), ") -> ", stringify!($SelfT), "{")]
/// let mut retval = 0;
#[doc = concat!(" for i in 0..", stringify!($SelfT), "::BITS {")]
/// if (rhs >> i) & 1 != 0 {
/// // long multiplication would use +=
/// retval ^= lhs << i;
/// }
/// }
/// retval
/// }
/// ```
///
/// The actual implementation is more efficient, and on some platforms lowers directly to a
/// dedicated instruction.
///
/// # Uses
///
/// Carryless multiplication can be used to turn a bitmask of quote characters into a
/// bit mask of characters surrounded by quotes:
///
/// ```no_run
/// r#"abc xxx "foobar" zzz "a"!"#; // input string
/// 0b0000000010000001000001010; // quote_mask
/// 0b0000000001111110000000100; // quote_mask.carryless_mul(!0) & !quote_mask
/// ```
///
/// Another use is in cryptography, where carryless multiplication allows for efficient
/// implementations of polynomial multiplication in `GF(2)[X]`, the polynomial ring
/// over `GF(2)`.
///
/// # Examples
///
/// ```
/// #![feature(uint_carryless_mul)]
///
#[doc = concat!("let a = ", $clmul_lhs, stringify!($SelfT), ";")]
#[doc = concat!("let b = ", $clmul_rhs, stringify!($SelfT), ";")]
///
#[doc = concat!("assert_eq!(a.carryless_mul(b), ", $clmul_result, ");")]
/// ```
#[rustc_const_unstable(feature = "uint_carryless_mul", issue = "152080")]
#[doc(alias = "clmul")]
#[unstable(feature = "uint_carryless_mul", issue = "152080")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn carryless_mul(self, rhs: Self) -> Self {
intrinsics::carryless_mul(self, rhs)
}
/// Reverses the byte order of the integer.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
/// let m = n.swap_bytes();
///
#[doc = concat!("assert_eq!(m, ", $swapped, ");")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn swap_bytes(self) -> Self {
intrinsics::bswap(self as $ActualT) as Self
}
/// Returns an integer with the bit locations specified by `mask` packed
/// contiguously into the least significant bits of the result.
/// ```
/// #![feature(uint_gather_scatter_bits)]
#[doc = concat!("let n: ", stringify!($SelfT), " = 0b1011_1100;")]
///
/// assert_eq!(n.extract_bits(0b0010_0100), 0b0000_0011);
/// assert_eq!(n.extract_bits(0xF0), 0b0000_1011);
/// ```
#[unstable(feature = "uint_gather_scatter_bits", issue = "149069")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn extract_bits(self, mask: Self) -> Self {
imp::int_bits::$ActualT::extract_impl(self as $ActualT, mask as $ActualT) as $SelfT
}
/// Returns an integer with the least significant bits of `self`
/// distributed to the bit locations specified by `mask`.
/// ```
/// #![feature(uint_gather_scatter_bits)]
#[doc = concat!("let n: ", stringify!($SelfT), " = 0b1010_1101;")]
///
/// assert_eq!(n.deposit_bits(0b0101_0101), 0b0101_0001);
/// assert_eq!(n.deposit_bits(0xF0), 0b1101_0000);
/// ```
#[unstable(feature = "uint_gather_scatter_bits", issue = "149069")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn deposit_bits(self, mask: Self) -> Self {
imp::int_bits::$ActualT::deposit_impl(self as $ActualT, mask as $ActualT) as $SelfT
}
/// 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
///
/// ```
#[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
/// let m = n.reverse_bits();
///
#[doc = concat!("assert_eq!(m, ", $reversed, ");")]
#[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
/// ```
#[stable(feature = "reverse_bits", since = "1.37.0")]
#[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn reverse_bits(self) -> Self {
intrinsics::bitreverse(self as $ActualT) as Self
}
/// Converts an integer from big endian to the target's endianness.
///
/// On big endian this is a no-op. On little endian the bytes are
/// swapped.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "big") {
#[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
/// } else {
#[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use]
#[inline(always)]
pub const fn from_be(x: Self) -> Self {
#[cfg(target_endian = "big")]
{
x
}
#[cfg(not(target_endian = "big"))]
{
x.swap_bytes()
}
}
/// 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
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "little") {
#[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
/// } else {
#[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use]
#[inline(always)]
pub const fn from_le(x: Self) -> Self {
#[cfg(target_endian = "little")]
{
x
}
#[cfg(not(target_endian = "little"))]
{
x.swap_bytes()
}
}
/// Converts `self` to big endian from the target's endianness.
///
/// On big endian this is a no-op. On little endian the bytes are
/// swapped.
///
/// # Examples
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "big") {
/// assert_eq!(n.to_be(), n)
/// } else {
/// assert_eq!(n.to_be(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn to_be(self) -> Self { // or not to be?
#[cfg(target_endian = "big")]
{
self
}
#[cfg(not(target_endian = "big"))]
{
self.swap_bytes()
}
}
/// 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
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "little") {
/// assert_eq!(n.to_le(), n)
/// } else {
/// assert_eq!(n.to_le(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn to_le(self) -> Self {
#[cfg(target_endian = "little")]
{
self
}
#[cfg(not(target_endian = "little"))]
{
self.swap_bytes()
}
}
/// Checked integer addition. Computes `self + rhs`, returning `None`
/// if overflow occurred.
///
/// # Examples
///
/// ```
#[doc = concat!(
"assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ",
"Some(", stringify!($SelfT), "::MAX - 1));"
)]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_add(self, rhs: Self) -> Option<Self> {
// This used to use `overflowing_add`, but that means it ends up being
// a `wrapping_add`, losing some optimization opportunities. Notably,
// phrasing it this way helps `.checked_add(1)` optimize to a check
// against `MAX` and a `add nuw`.
// Per <https://github.com/rust-lang/rust/pull/124114#issuecomment-2066173305>,
// LLVM is happy to re-form the intrinsic later if useful.
if intrinsics::unlikely(intrinsics::add_with_overflow(self, rhs).1) {
None
} else {
// SAFETY: Just checked it doesn't overflow
Some(unsafe { intrinsics::unchecked_add(self, rhs) })
}
}
/// 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
///
/// ```
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
/// ```
///
/// The following panics because of overflow:
///
/// ```should_panic
#[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_add(self, rhs: Self) -> Self {
let (a, b) = self.overflowing_add(rhs);
if b { imp::overflow_panic::add() } else { a }
}
/// Unchecked integer addition. Computes `self + rhs`, assuming overflow
/// cannot occur.
///
/// Calling `x.unchecked_add(y)` is semantically equivalent to calling
/// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
///
/// If you're just trying to avoid the panic in debug mode, then **do not**
/// use this. Instead, you're looking for [`wrapping_add`].
///
/// # Safety
///
/// This results in undefined behavior when
#[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
/// i.e. when [`checked_add`] would return `None`.
///
/// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
#[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
#[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
#[stable(feature = "unchecked_math", since = "1.79.0")]
#[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
(
lhs: $SelfT = self,
rhs: $SelfT = rhs,
) => !lhs.overflowing_add(rhs).1,
);
// SAFETY: this is guaranteed to be safe by the caller.
unsafe {
intrinsics::unchecked_add(self, rhs)
}
}
/// Checked addition with a signed integer. Computes `self + rhs`,
/// returning `None` if overflow occurred.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")]
/// ```
#[stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
let (a, b) = self.overflowing_add_signed(rhs);
if intrinsics::unlikely(b) { None } else { Some(a) }
}
/// Strict addition with a signed integer. Computes `self + rhs`,
/// panicking if overflow occurred.
///
/// # Panics
///
/// ## Overflow behavior
///
/// This function will always panic on overflow, regardless of whether overflow checks are enabled.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_signed(2), 3);")]
/// ```
///
/// The following panic because of overflow:
///
/// ```should_panic
#[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_add_signed(-2);")]
/// ```
///
/// ```should_panic
#[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_signed(3);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_add_signed(self, rhs: $SignedT) -> Self {
let (a, b) = self.overflowing_add_signed(rhs);
if b { imp::overflow_panic::add() } else { a }
}
/// Checked integer subtraction. Computes `self - rhs`, returning
/// `None` if overflow occurred.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")]
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
// Per PR#103299, there's no advantage to the `overflowing` intrinsic
// for *unsigned* subtraction and we just emit the manual check anyway.
// Thus, rather than using `overflowing_sub` that produces a wrapping
// subtraction, check it ourself so we can use an unchecked one.
if self < rhs {
None
} else {
// SAFETY: just checked this can't overflow
Some(unsafe { intrinsics::unchecked_sub(self, rhs) })
}
}
/// Strict integer subtraction. Computes `self - rhs`, panicking if
/// overflow occurred.
///
/// # Panics
///
/// ## Overflow behavior
///
/// This function will always panic on overflow, regardless of whether overflow checks are enabled.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub(1), 0);")]
/// ```
///
/// The following panics because of overflow:
///
/// ```should_panic
#[doc = concat!("let _ = 0", stringify!($SelfT), ".strict_sub(1);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_sub(self, rhs: Self) -> Self {
let (a, b) = self.overflowing_sub(rhs);
if b { imp::overflow_panic::sub() } else { a }
}
/// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
/// cannot occur.
///
/// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
/// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
///
/// If you're just trying to avoid the panic in debug mode, then **do not**
/// use this. Instead, you're looking for [`wrapping_sub`].
///
/// If you find yourself writing code like this:
///
/// ```
/// # let foo = 30_u32;
/// # let bar = 20;
/// if foo >= bar {
/// // SAFETY: just checked it will not overflow
/// let diff = unsafe { foo.unchecked_sub(bar) };
/// // ... use diff ...
/// }
/// ```
///
/// Consider changing it to
///
/// ```
/// # let foo = 30_u32;
/// # let bar = 20;
/// if let Some(diff) = foo.checked_sub(bar) {
/// // ... use diff ...
/// }
/// ```
///
/// As that does exactly the same thing -- including telling the optimizer
/// that the subtraction cannot overflow -- but avoids needing `unsafe`.
///
/// # Safety
///
/// This results in undefined behavior when
#[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
/// i.e. when [`checked_sub`] would return `None`.
///
/// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
#[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
#[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
#[stable(feature = "unchecked_math", since = "1.79.0")]
#[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
(
lhs: $SelfT = self,
rhs: $SelfT = rhs,
) => !lhs.overflowing_sub(rhs).1,
);
// SAFETY: this is guaranteed to be safe by the caller.
unsafe {
intrinsics::unchecked_sub(self, rhs)
}
}
/// Checked subtraction with a signed integer. Computes `self - rhs`,
/// returning `None` if overflow occurred.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(2), None);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(-2), Some(3));")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_sub_signed(-4), None);")]
/// ```
#[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
#[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_sub_signed(self, rhs: $SignedT) -> Option<Self> {
let (res, overflow) = self.overflowing_sub_signed(rhs);
if !overflow {
Some(res)
} else {
None
}
}
/// Strict subtraction with a signed integer. Computes `self - rhs`,
/// panicking if overflow occurred.
///
/// # Panics
///
/// ## Overflow behavior
///
/// This function will always panic on overflow, regardless of whether overflow checks are enabled.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".strict_sub_signed(2), 1);")]
/// ```
///
/// The following panic because of overflow:
///
/// ```should_panic
#[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_sub_signed(2);")]
/// ```
///
/// ```should_panic
#[doc = concat!("let _ = (", stringify!($SelfT), "::MAX).strict_sub_signed(-1);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_sub_signed(self, rhs: $SignedT) -> Self {
let (a, b) = self.overflowing_sub_signed(rhs);
if b { imp::overflow_panic::sub() } else { a }
}
#[doc = concat!(
"Checked integer subtraction. Computes `self - rhs` and checks if the result fits into an [`",
stringify!($SignedT), "`], returning `None` if overflow occurred."
)]
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_signed_diff(2), Some(8));")]
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_signed_diff(10), Some(-8));")]
#[doc = concat!(
"assert_eq!(",
stringify!($SelfT),
"::MAX.checked_signed_diff(",
stringify!($SignedT),
"::MAX as ",
stringify!($SelfT),
"), None);"
)]
#[doc = concat!(
"assert_eq!((",
stringify!($SignedT),
"::MAX as ",
stringify!($SelfT),
").checked_signed_diff(",
stringify!($SelfT),
"::MAX), Some(",
stringify!($SignedT),
"::MIN));"
)]
#[doc = concat!(
"assert_eq!((",
stringify!($SignedT),
"::MAX as ",
stringify!($SelfT),
" + 1).checked_signed_diff(0), None);"
)]
#[doc = concat!(
"assert_eq!(",
stringify!($SelfT),
"::MAX.checked_signed_diff(",
stringify!($SelfT),
"::MAX), Some(0));"
)]
/// ```
#[stable(feature = "unsigned_signed_diff", since = "1.91.0")]
#[rustc_const_stable(feature = "unsigned_signed_diff", since = "1.91.0")]
#[inline]
pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> {
let res = self.wrapping_sub(rhs) as $SignedT;
let overflow = (self >= rhs) == (res < 0);
if !overflow {
Some(res)
} else {
None
}
}
/// Checked integer multiplication. Computes `self * rhs`, returning
/// `None` if overflow occurred.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_mul(rhs);
if intrinsics::unlikely(b) { None } else { Some(a) }
}
/// Strict integer multiplication. Computes `self * rhs`, panicking if
/// overflow occurred.
///
/// # Panics
///
/// ## Overflow behavior
///
/// This function will always panic on overflow, regardless of whether overflow checks are enabled.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_mul(1), 5);")]
/// ```
///
/// The following panics because of overflow:
///
/// ``` should_panic
#[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_mul(self, rhs: Self) -> Self {
let (a, b) = self.overflowing_mul(rhs);
if b { imp::overflow_panic::mul() } else { a }
}
/// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
/// cannot occur.
///
/// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
/// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
///
/// If you're just trying to avoid the panic in debug mode, then **do not**
/// use this. Instead, you're looking for [`wrapping_mul`].
///
/// # Safety
///
/// This results in undefined behavior when
#[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
/// i.e. when [`checked_mul`] would return `None`.
///
/// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
#[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
#[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
#[stable(feature = "unchecked_math", since = "1.79.0")]
#[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
(
lhs: $SelfT = self,
rhs: $SelfT = rhs,
) => !lhs.overflowing_mul(rhs).1,
);
// SAFETY: this is guaranteed to be safe by the caller.
unsafe {
intrinsics::unchecked_mul(self, rhs)
}
}
/// Checked integer division. Computes `self / rhs`, returning `None`
/// if `rhs == 0`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_div(self, rhs: Self) -> Option<Self> {
if intrinsics::unlikely(rhs == 0) {
None
} else {
// SAFETY: div by zero has been checked above and unsigned types have no other
// failure modes for division
Some(unsafe { intrinsics::unchecked_div(self, rhs) })
}
}
/// Strict integer division. Computes `self / rhs`.
///
/// Strict division on unsigned types is just normal division. There's no
/// way overflow could ever happen. This function exists so that all
/// operations are accounted for in the strict operations.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div(10), 10);")]
/// ```
///
/// The following panics because of division by zero:
///
/// ```should_panic
#[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn strict_div(self, rhs: Self) -> Self {
self / rhs
}
/// Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None`
/// if `rhs == 0`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
if intrinsics::unlikely(rhs == 0) {
None
} else {
Some(self.div_euclid(rhs))
}
}
/// Strict Euclidean division. Computes `self.div_euclid(rhs)`.
///
/// Strict division on unsigned types is just normal division. There's no
/// way overflow could ever happen. This function exists so that all
/// operations are accounted for in the strict operations. Since, for the
/// positive integers, all common definitions of division are equal, this
/// is exactly equal to `self.strict_div(rhs)`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div_euclid(10), 10);")]
/// ```
/// The following panics because of division by zero:
///
/// ```should_panic
#[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn strict_div_euclid(self, rhs: Self) -> Self {
self / rhs
}
/// Checked integer division without remainder. Computes `self / rhs`,
/// returning `None` if `rhs == 0` or if `self % rhs != 0`.
///
/// # Examples
///
/// ```
/// #![feature(exact_div)]
#[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(2), Some(32));")]
#[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(32), Some(2));")]
#[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(0), None);")]
#[doc = concat!("assert_eq!(65", stringify!($SelfT), ".checked_div_exact(2), None);")]
/// ```
#[unstable(
feature = "exact_div",
issue = "139911",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_div_exact(self, rhs: Self) -> Option<Self> {
if intrinsics::unlikely(rhs == 0) {
None
} else {
// SAFETY: division by zero is checked above
unsafe {
if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) {
None
} else {
Some(intrinsics::exact_div(self, rhs))
}
}
}
}
/// Integer division without remainder. Computes `self / rhs`, returning `None` if `self % rhs != 0`.
///
/// # Panics
///
/// This function will panic if `rhs == 0`.
///
/// # Examples
///
/// ```
/// #![feature(exact_div)]
#[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(2), Some(32));")]
#[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(32), Some(2));")]
#[doc = concat!("assert_eq!(65", stringify!($SelfT), ".div_exact(2), None);")]
/// ```
#[unstable(
feature = "exact_div",
issue = "139911",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn div_exact(self, rhs: Self) -> Option<Self> {
if self % rhs != 0 {
None
} else {
Some(self / rhs)
}
}
/// Unchecked integer division without remainder. Computes `self / rhs`.
///
/// # Safety
///
/// This results in undefined behavior when `rhs == 0` or `self % rhs != 0`,
/// i.e. when [`checked_div_exact`](Self::checked_div_exact) would return `None`.
#[unstable(
feature = "exact_div",
issue = "139911",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const unsafe fn unchecked_div_exact(self, rhs: Self) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_div_exact divide by zero or leave a remainder"),
(
lhs: $SelfT = self,
rhs: $SelfT = rhs,
) => rhs > 0 && lhs % rhs == 0,
);
// SAFETY: Same precondition
unsafe { intrinsics::exact_div(self, rhs) }
}
/// Checked integer remainder. Computes `self % rhs`, returning `None`
/// if `rhs == 0`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
if intrinsics::unlikely(rhs == 0) {
None
} else {
// SAFETY: div by zero has been checked above and unsigned types have no other
// failure modes for division
Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
}
}
/// Strict integer remainder. Computes `self % rhs`.
///
/// Strict remainder calculation on unsigned types is just the regular
/// remainder calculation. There's no way overflow could ever happen.
/// This function exists so that all operations are accounted for in the
/// strict operations.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem(10), 0);")]
/// ```
///
/// The following panics because of division by zero:
///
/// ```should_panic
#[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn strict_rem(self, rhs: Self) -> Self {
self % rhs
}
/// Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None`
/// if `rhs == 0`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
if intrinsics::unlikely(rhs == 0) {
None
} else {
Some(self.rem_euclid(rhs))
}
}
/// Strict Euclidean modulo. Computes `self.rem_euclid(rhs)`.
///
/// Strict modulo calculation on unsigned types is just the regular
/// remainder calculation. There's no way overflow could ever happen.
/// This function exists so that all operations are accounted for in the
/// strict operations. Since, for the positive integers, all common
/// definitions of division are equal, this is exactly equal to
/// `self.strict_rem(rhs)`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem_euclid(10), 0);")]
/// ```
///
/// The following panics because of division by zero:
///
/// ```should_panic
#[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
self % rhs
}
/// Same value as `self | other`, but UB if any bit position is set in both inputs.
///
/// This is a situational micro-optimization for places where you'd rather
/// use addition on some platforms and bitwise or on other platforms, based
/// on exactly which instructions combine better with whatever else you're
/// doing. Note that there's no reason to bother using this for places
/// where it's clear from the operations involved that they can't overlap.
/// For example, if you're combining `u16`s into a `u32` with
/// `((a as u32) << 16) | (b as u32)`, that's fine, as the backend will
/// know those sides of the `|` are disjoint without needing help.
///
/// # Examples
///
/// ```
/// #![feature(disjoint_bitor)]
///
/// // SAFETY: `1` and `4` have no bits in common.
/// unsafe {
#[doc = concat!(" assert_eq!(1_", stringify!($SelfT), ".unchecked_disjoint_bitor(4), 5);")]
/// }
/// ```
///
/// # Safety
///
/// Requires that `(self & other) == 0`, otherwise it's immediate UB.
///
/// Equivalently, requires that `(self | other) == (self + other)`.
#[unstable(feature = "disjoint_bitor", issue = "135758")]
#[rustc_const_unstable(feature = "disjoint_bitor", issue = "135758")]
#[inline]
pub const unsafe fn unchecked_disjoint_bitor(self, other: Self) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_disjoint_bitor cannot have overlapping bits"),
(
lhs: $SelfT = self,
rhs: $SelfT = other,
) => (lhs & rhs) == 0,
);
// SAFETY: Same precondition
unsafe { intrinsics::disjoint_bitor(self, other) }
}
/// Returns the logarithm of the number with respect to an arbitrary base,
/// rounded down.
///
/// This method might not be optimized owing to implementation details;
/// `ilog2` can produce results more efficiently for base 2, and `ilog10`
/// can produce results more efficiently for base 10.
///
/// # Panics
///
/// This function will panic if `self` is zero, or if `base` is less than 2.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn ilog(self, base: Self) -> u32 {
assert!(base >= 2, "base of integer logarithm must be at least 2");
if let Some(log) = self.checked_ilog(base) {
log
} else {
imp::int_log10::panic_for_nonpositive_argument()
}
}
/// Returns the base 2 logarithm of the number, rounded down.
///
/// # Panics
///
/// This function will panic if `self` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn ilog2(self) -> u32 {
if let Some(log) = self.checked_ilog2() {
log
} else {
imp::int_log10::panic_for_nonpositive_argument()
}
}
/// Returns the base 10 logarithm of the number, rounded down.
///
/// # Panics
///
/// This function will panic if `self` is zero.
///
/// # Example
///
/// ```
#[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn ilog10(self) -> u32 {
if let Some(log) = self.checked_ilog10() {
log
} else {
imp::int_log10::panic_for_nonpositive_argument()
}
}
/// Returns the logarithm of the number with respect to an arbitrary base,
/// rounded down.
///
/// Returns `None` if the number is zero, or if the base is not at least 2.
///
/// This method might not be optimized owing to implementation details;
/// `checked_ilog2` can produce results more efficiently for base 2, and
/// `checked_ilog10` can produce results more efficiently for base 10.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_ilog(self, base: Self) -> Option<u32> {
// Inform compiler of optimizations when the base is known at
// compile time and there's a cheaper method available.
//
// Note: Like all optimizations, this is not guaranteed to be
// applied by the compiler. If you want those specific bases,
// use `.checked_ilog2()` or `.checked_ilog10()` directly.
if core::intrinsics::is_val_statically_known(base) {
if base == 2 {
return self.checked_ilog2();
} else if base == 10 {
return self.checked_ilog10();
}
}
if self <= 0 || base <= 1 {
None
} else if self < base {
Some(0)
} else {
// Since base >= self, n >= 1
let mut n = 1;
let mut r = base;
// Optimization for 128 bit wide integers.
if Self::BITS == 128 {
// The following is a correct lower bound for ⌊log(base,self)⌋ because
//
// log(base,self) = log(2,self) / log(2,base)
// ≥ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1)
//
// hence
//
// ⌊log(base,self)⌋ ≥ ⌊ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1) ⌋ .
n = self.ilog2() / (base.ilog2() + 1);
r = base.pow(n);
}
while r <= self / base {
n += 1;
r *= base;
}
Some(n)
}
}
/// Returns the base 2 logarithm of the number, rounded down.
///
/// Returns `None` if the number is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_ilog2(self) -> Option<u32> {
match NonZero::new(self) {
Some(x) => Some(x.ilog2()),
None => None,
}
}
/// Returns the base 10 logarithm of the number, rounded down.
///
/// Returns `None` if the number is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
/// ```
#[stable(feature = "int_log", since = "1.67.0")]
#[rustc_const_stable(feature = "int_log", since = "1.67.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_ilog10(self) -> Option<u32> {
match NonZero::new(self) {
Some(x) => Some(x.ilog10()),
None => None,
}
}
/// Checked negation. Computes `-self`, returning `None` unless `self ==
/// 0`.
///
/// Note that negating any positive integer will overflow.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_neg(self) -> Option<Self> {
let (a, b) = self.overflowing_neg();
if intrinsics::unlikely(b) { None } else { Some(a) }
}
/// Strict negation. Computes `-self`, panicking unless `self ==
/// 0`.
///
/// Note that negating any positive integer will overflow.
///
/// # Panics
///
/// ## Overflow behavior
///
/// This function will always panic on overflow, regardless of whether overflow checks are enabled.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".strict_neg(), 0);")]
/// ```
///
/// The following panics because of overflow:
///
/// ```should_panic
#[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_neg();")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_neg(self) -> Self {
let (a, b) = self.overflowing_neg();
if b { imp::overflow_panic::neg() } else { a }
}
/// Checked shift left. Computes `self << rhs`, returning `None`
/// if `rhs` is larger than or equal to the number of bits in `self`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
// Not using overflowing_shl as that's a wrapping shift
if rhs < Self::BITS {
// SAFETY: just checked the RHS is in-range
Some(unsafe { self.unchecked_shl(rhs) })
} else {
None
}
}
/// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
/// than or equal to the number of bits in `self`.
///
/// # Panics
///
/// ## Overflow behavior
///
/// This function will always panic on overflow, regardless of whether overflow checks are enabled.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
/// ```
///
/// The following panics because of overflow:
///
/// ```should_panic
#[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shl(129);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_shl(self, rhs: u32) -> Self {
let (a, b) = self.overflowing_shl(rhs);
if b { imp::overflow_panic::shl() } else { a }
}
/// Unchecked shift left. Computes `self << rhs`, assuming that
/// `rhs` is less than the number of bits in `self`.
///
/// # Safety
///
/// This results in undefined behavior if `rhs` is larger than
/// or equal to the number of bits in `self`,
/// i.e. when [`checked_shl`] would return `None`.
///
#[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
#[stable(feature = "unchecked_shifts", since = "1.93.0")]
#[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
(
rhs: u32 = rhs,
) => rhs < <$ActualT>::BITS,
);
// SAFETY: this is guaranteed to be safe by the caller.
unsafe {
intrinsics::unchecked_shl(self, rhs)
}
}
/// 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
///
/// ```
#[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
#[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(129), 0);")]
#[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(0), 0b101);")]
#[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(1), 0b1010);")]
#[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(2), 0b10100);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(", stringify!($BITS), "), 0);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(1).unbounded_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
///
#[doc = concat!("let start : ", stringify!($SelfT), " = 13;")]
/// let mut running = start;
/// for i in 0..160 {
/// // The unbounded shift left by i is the same as `<< 1` i times
/// assert_eq!(running, start.unbounded_shl(i));
/// // Which is not always the case for a wrapping shift
#[doc = concat!(" assert_eq!(running == start.wrapping_shl(i), i < ", stringify!($BITS), ");")]
///
/// running <<= 1;
/// }
/// ```
#[stable(feature = "unbounded_shifts", since = "1.87.0")]
#[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
if rhs < Self::BITS {
// SAFETY:
// rhs is just checked to be in-range above
unsafe { self.unchecked_shl(rhs) }
} else {
0
}
}
/// Exact shift left. Computes `self << rhs` as long as it can be reversed losslessly.
///
/// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
#[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
/// Otherwise, returns `Some(self << rhs)`.
///
/// # Examples
///
/// ```
/// #![feature(exact_bitshifts)]
///
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(4), Some(0x10));")]
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(129), None);")]
/// ```
#[unstable(feature = "exact_bitshifts", issue = "144336")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn shl_exact(self, rhs: u32) -> Option<$SelfT> {
if rhs <= self.leading_zeros() && rhs < <$SelfT>::BITS {
// SAFETY: rhs is checked above
Some(unsafe { self.unchecked_shl(rhs) })
} else {
None
}
}
/// Unchecked exact shift left. Computes `self << rhs`, assuming the operation can be
/// losslessly reversed `rhs` cannot be larger than
#[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
///
/// # Safety
///
/// This results in undefined behavior when `rhs > self.leading_zeros() || rhs >=
#[doc = concat!(stringify!($SelfT), "::BITS`")]
/// i.e. when
#[doc = concat!("[`", stringify!($SelfT), "::shl_exact`]")]
/// would return `None`.
#[unstable(feature = "exact_bitshifts", issue = "144336")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const unsafe fn unchecked_shl_exact(self, rhs: u32) -> $SelfT {
assert_unsafe_precondition!(
check_library_ub,
concat!(stringify!($SelfT), "::unchecked_shl_exact cannot shift out non-zero bits"),
(
zeros: u32 = self.leading_zeros(),
bits: u32 = <$SelfT>::BITS,
rhs: u32 = rhs,
) => rhs <= zeros && rhs < bits,
);
// SAFETY: this is guaranteed to be safe by the caller
unsafe { self.unchecked_shl(rhs) }
}
/// Checked shift right. Computes `self >> rhs`, returning `None`
/// if `rhs` is larger than or equal to the number of bits in `self`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
// Not using overflowing_shr as that's a wrapping shift
if rhs < Self::BITS {
// SAFETY: just checked the RHS is in-range
Some(unsafe { self.unchecked_shr(rhs) })
} else {
None
}
}
/// Strict shift right. Computes `self >> rhs`, panicking if `rhs` is
/// larger than or equal to the number of bits in `self`.
///
/// # Panics
///
/// ## Overflow behavior
///
/// This function will always panic on overflow, regardless of whether overflow checks are enabled.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
/// ```
///
/// The following panics because of overflow:
///
/// ```should_panic
#[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(129);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_shr(self, rhs: u32) -> Self {
let (a, b) = self.overflowing_shr(rhs);
if b { imp::overflow_panic::shr() } else { a }
}
/// Unchecked shift right. Computes `self >> rhs`, assuming that
/// `rhs` is less than the number of bits in `self`.
///
/// # Safety
///
/// This results in undefined behavior if `rhs` is larger than
/// or equal to the number of bits in `self`,
/// i.e. when [`checked_shr`] would return `None`.
///
#[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
#[stable(feature = "unchecked_shifts", since = "1.93.0")]
#[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
assert_unsafe_precondition!(
check_language_ub,
concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
(
rhs: u32 = rhs,
) => rhs < <$ActualT>::BITS,
);
// SAFETY: this is guaranteed to be safe by the caller.
unsafe {
intrinsics::unchecked_shr(self, rhs)
}
}
/// 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, and `0` is returned.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
#[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(129), 0);")]
#[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(0), 0b1010);")]
#[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(1), 0b101);")]
#[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(2), 0b10);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(", stringify!($BITS), "), 0);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(1).unbounded_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
///
#[doc = concat!("let start = ", stringify!($SelfT), "::rotate_right(13, 4);")]
/// let mut running = start;
/// for i in 0..160 {
/// // The unbounded shift right by i is the same as `>> 1` i times
/// assert_eq!(running, start.unbounded_shr(i));
/// // Which is not always the case for a wrapping shift
#[doc = concat!(" assert_eq!(running == start.wrapping_shr(i), i < ", stringify!($BITS), ");")]
///
/// running >>= 1;
/// }
/// ```
#[stable(feature = "unbounded_shifts", since = "1.87.0")]
#[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
if rhs < Self::BITS {
// SAFETY:
// rhs is just checked to be in-range above
unsafe { self.unchecked_shr(rhs) }
} else {
0
}
}
/// Exact shift right. Computes `self >> rhs` as long as it can be reversed losslessly.
///
/// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
#[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
/// Otherwise, returns `Some(self >> rhs)`.
///
/// # Examples
///
/// ```
/// #![feature(exact_bitshifts)]
///
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(4), Some(0x1));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(5), None);")]
/// ```
#[unstable(feature = "exact_bitshifts", issue = "144336")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn shr_exact(self, rhs: u32) -> Option<$SelfT> {
if rhs <= self.trailing_zeros() && rhs < <$SelfT>::BITS {
// SAFETY: rhs is checked above
Some(unsafe { self.unchecked_shr(rhs) })
} else {
None
}
}
/// Unchecked exact shift right. Computes `self >> rhs`, assuming the operation can be
/// losslessly reversed and `rhs` cannot be larger than
#[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
///
/// # Safety
///
/// This results in undefined behavior when `rhs > self.trailing_zeros() || rhs >=
#[doc = concat!(stringify!($SelfT), "::BITS`")]
/// i.e. when
#[doc = concat!("[`", stringify!($SelfT), "::shr_exact`]")]
/// would return `None`.
#[unstable(feature = "exact_bitshifts", issue = "144336")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const unsafe fn unchecked_shr_exact(self, rhs: u32) -> $SelfT {
assert_unsafe_precondition!(
check_library_ub,
concat!(stringify!($SelfT), "::unchecked_shr_exact cannot shift out non-zero bits"),
(
zeros: u32 = self.trailing_zeros(),
bits: u32 = <$SelfT>::BITS,
rhs: u32 = rhs,
) => rhs <= zeros && rhs < bits,
);
// SAFETY: this is guaranteed to be safe by the caller
unsafe { self.unchecked_shr(rhs) }
}
/// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
/// overflow occurred.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")]
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".checked_pow(0), Some(1));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
if exp == 0 {
return Some(1);
}
let mut base = self;
let mut acc: Self = 1;
loop {
if (exp & 1) == 1 {
acc = try_opt!(acc.checked_mul(base));
// since exp!=0, finally the exp must be 1.
if exp == 1 {
return Some(acc);
}
}
exp /= 2;
base = try_opt!(base.checked_mul(base));
}
}
/// 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
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".strict_pow(5), 32);")]
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".strict_pow(0), 1);")]
/// ```
///
/// The following panics because of overflow:
///
/// ```should_panic
#[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
/// ```
#[stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn strict_pow(self, mut exp: u32) -> Self {
if exp == 0 {
return 1;
}
let mut base = self;
let mut acc: Self = 1;
loop {
if (exp & 1) == 1 {
acc = acc.strict_mul(base);
// since exp!=0, finally the exp must be 1.
if exp == 1 {
return acc;
}
}
exp /= 2;
base = base.strict_mul(base);
}
}
/// Saturating integer addition. Computes `self + rhs`, saturating at
/// the numeric bounds instead of overflowing.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
#[inline(always)]
pub const fn saturating_add(self, rhs: Self) -> Self {
intrinsics::saturating_add(self, rhs)
}
/// Saturating addition with a signed integer. Computes `self + rhs`,
/// saturating at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")]
/// ```
#[stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
let (res, overflow) = self.overflowing_add(rhs as Self);
if overflow == (rhs < 0) {
res
} else if overflow {
Self::MAX
} else {
0
}
}
/// Saturating integer subtraction. Computes `self - rhs`, saturating
/// at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")]
#[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
#[inline(always)]
pub const fn saturating_sub(self, rhs: Self) -> Self {
intrinsics::saturating_sub(self, rhs)
}
/// Saturating integer subtraction. Computes `self` - `rhs`, saturating at
/// the numeric bounds instead of overflowing.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(2), 0);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(-2), 3);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_sub_signed(-4), ", stringify!($SelfT), "::MAX);")]
/// ```
#[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
#[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_sub_signed(self, rhs: $SignedT) -> Self {
let (res, overflow) = self.overflowing_sub_signed(rhs);
if !overflow {
res
} else if rhs < 0 {
Self::MAX
} else {
0
}
}
/// Saturating integer multiplication. Computes `self * rhs`,
/// saturating at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT),"::MAX);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_mul(self, rhs: Self) -> Self {
match self.checked_mul(rhs) {
Some(x) => x,
None => Self::MAX,
}
}
/// Saturating integer division. Computes `self / rhs`, saturating at the
/// numeric bounds instead of overflowing.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
///
/// ```
#[stable(feature = "saturating_div", since = "1.58.0")]
#[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn saturating_div(self, rhs: Self) -> Self {
// on unsigned types, there is no overflow in integer division
self.wrapping_div(rhs)
}
/// Saturating integer exponentiation. Computes `self.pow(exp)`,
/// saturating at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")]
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".saturating_pow(0), 1);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_pow(self, exp: u32) -> Self {
match self.checked_pow(exp) {
Some(x) => x,
None => Self::MAX,
}
}
/// Wrapping (modular) addition. Computes `self + rhs`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255);")]
#[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_add(self, rhs: Self) -> Self {
intrinsics::wrapping_add(self, rhs)
}
/// Wrapping (modular) addition with a signed integer. Computes
/// `self + rhs`, wrapping around at the boundary of the type.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")]
/// ```
#[stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self {
self.wrapping_add(rhs as Self)
}
/// Wrapping (modular) subtraction. Computes `self - rhs`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0);")]
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_sub(self, rhs: Self) -> Self {
intrinsics::wrapping_sub(self, rhs)
}
/// Wrapping (modular) subtraction with a signed integer. Computes
/// `self - rhs`, wrapping around at the boundary of the type.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(2), ", stringify!($SelfT), "::MAX);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(-2), 3);")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_sub_signed(-4), 1);")]
/// ```
#[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
#[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn wrapping_sub_signed(self, rhs: $SignedT) -> Self {
self.wrapping_sub(rhs as Self)
}
/// Wrapping (modular) multiplication. Computes `self *
/// rhs`, wrapping around at the boundary of the type.
///
/// # Examples
///
/// Please note that this example is shared among integer types, which is why `u8` is used.
///
/// ```
/// assert_eq!(10u8.wrapping_mul(12), 120);
/// assert_eq!(25u8.wrapping_mul(12), 44);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_mul(self, rhs: Self) -> Self {
intrinsics::wrapping_mul(self, rhs)
}
/// Wrapping (modular) division. Computes `self / rhs`.
///
/// Wrapped division on unsigned types is just normal division. There's
/// no way wrapping could ever happen. This function exists so that all
/// operations are accounted for in the wrapping operations.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn wrapping_div(self, rhs: Self) -> Self {
self / rhs
}
/// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`.
///
/// Wrapped division on unsigned types is just normal division. There's
/// no way wrapping could ever happen. This function exists so that all
/// operations are accounted for in the wrapping operations. Since, for
/// the positive integers, all common definitions of division are equal,
/// this is exactly equal to `self.wrapping_div(rhs)`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
self / rhs
}
/// Wrapping (modular) remainder. Computes `self % rhs`.
///
/// Wrapped remainder calculation on unsigned types is just the regular
/// remainder calculation. There's no way wrapping could ever happen.
/// This function exists so that all operations are accounted for in the
/// wrapping operations.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn wrapping_rem(self, rhs: Self) -> Self {
self % rhs
}
/// Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`.
///
/// Wrapped modulo calculation on unsigned types is just the regular
/// remainder calculation. There's no way wrapping could ever happen.
/// This function exists so that all operations are accounted for in the
/// wrapping operations. Since, for the positive integers, all common
/// definitions of division are equal, this is exactly equal to
/// `self.wrapping_rem(rhs)`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
self % rhs
}
/// Wrapping (modular) negation. Computes `-self`,
/// wrapping around at the boundary of the type.
///
/// Since unsigned types do not have negative equivalents
/// all applications of this function will wrap (except for `-0`).
/// For values smaller than the corresponding signed type's maximum
/// the result is the same as casting the corresponding signed value.
/// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where
/// `MAX` is the corresponding signed type's maximum.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_neg(), 0);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_neg(), 1);")]
#[doc = concat!("assert_eq!(13_", stringify!($SelfT), ".wrapping_neg(), (!13) + 1);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_neg(), !(42 - 1));")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_neg(self) -> Self {
(0 as $SelfT).wrapping_sub(self)
}
/// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
/// where `mask` removes any high-order bits of `rhs` that
/// would cause the shift to exceed the bitwidth of the type.
///
/// Beware that, unlike most other `wrapping_*` methods on integers, this
/// does *not* give the same result as doing the shift in infinite precision
/// then truncating as needed. The behaviour matches what shift instructions
/// do on many processors, and is what the `<<` operator does when overflow
/// checks are disabled, but numerically it's weird. Consider, instead,
/// using [`Self::unbounded_shl`] which has nicer behaviour.
///
/// Note that this is *not* the same as a rotate-left; the
/// RHS of a wrapping shift-left is restricted to the range
/// of the type, rather than the bits shifted out of the LHS
/// being returned to the other end. The primitive integer
/// types all implement a [`rotate_left`](Self::rotate_left) function,
/// which may be what you want instead.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".wrapping_shl(7), 128);")]
#[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(0), 0b101);")]
#[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(1), 0b1010);")]
#[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(2), 0b10100);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_shl(2), ", stringify!($SelfT), "::MAX - 3);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(", stringify!($BITS), "), 42);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(1).wrapping_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
#[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".wrapping_shl(128), 1);")]
#[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".wrapping_shl(1025), 10);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_shl(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
self.unchecked_shl(rhs & (Self::BITS - 1))
}
}
/// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
/// where `mask` removes any high-order bits of `rhs` that
/// would cause the shift to exceed the bitwidth of the type.
///
/// Beware that, unlike most other `wrapping_*` methods on integers, this
/// does *not* give the same result as doing the shift in infinite precision
/// then truncating as needed. The behaviour matches what shift instructions
/// do on many processors, and is what the `>>` operator does when overflow
/// checks are disabled, but numerically it's weird. Consider, instead,
/// using [`Self::unbounded_shr`] which has nicer behaviour.
///
/// Note that this is *not* the same as a rotate-right; the
/// RHS of a wrapping shift-right is restricted to the range
/// of the type, rather than the bits shifted out of the LHS
/// being returned to the other end. The primitive integer
/// types all implement a [`rotate_right`](Self::rotate_right) function,
/// which may be what you want instead.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(128_", stringify!($SelfT), ".wrapping_shr(7), 1);")]
#[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(0), 0b1010);")]
#[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(1), 0b101);")]
#[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(2), 0b10);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_shr(1), ", stringify!($SignedT), "::MAX.cast_unsigned());")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(", stringify!($BITS), "), 42);")]
#[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(1).wrapping_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
#[doc = concat!("assert_eq!(128_", stringify!($SelfT), ".wrapping_shr(128), 128);")]
#[doc = concat!("assert_eq!(10_", stringify!($SelfT), ".wrapping_shr(1025), 5);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_shr(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
self.unchecked_shr(rhs & (Self::BITS - 1))
}
}
/// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")]
/// assert_eq!(3u8.wrapping_pow(6), 217);
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_pow(0), 1);")]
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn wrapping_pow(self, mut exp: u32) -> Self {
if exp == 0 {
return 1;
}
let mut base = self;
let mut acc: Self = 1;
if intrinsics::is_val_statically_known(exp) {
while exp > 1 {
if (exp & 1) == 1 {
acc = acc.wrapping_mul(base);
}
exp /= 2;
base = base.wrapping_mul(base);
}
// since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary.
acc.wrapping_mul(base)
} else {
// This is faster than the above when the exponent is not known
// at compile time. We can't use the same code for the constant
// exponent case because LLVM is currently unable to unroll
// this loop.
loop {
if (exp & 1) == 1 {
acc = acc.wrapping_mul(base);
// since exp!=0, finally the exp must be 1.
if exp == 1 {
return acc;
}
}
exp /= 2;
base = base.wrapping_mul(base);
}
}
}
/// Calculates `self` + `rhs`.
///
/// Returns a tuple of the addition along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
(a as Self, b)
}
/// Calculates `self` + `rhs` + `carry` and returns a tuple containing
/// the sum and the output carry (in that order).
///
/// Performs "ternary addition" of two integer operands and a carry-in
/// bit, and returns an output integer and a carry-out bit. This allows
/// chaining together multiple additions to create a wider addition, and
/// can be useful for bignum addition.
///
#[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit \"full adder\", in the electronics sense.")]
///
/// If the input carry is false, this method is equivalent to
/// [`overflowing_add`](Self::overflowing_add), and the output carry is
/// equal to the overflow flag. Note that although carry and overflow
/// flags are similar for unsigned integers, they are different for
/// signed integers.
///
/// # Examples
///
/// ```
#[doc = concat!("// 3 MAX (a = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
#[doc = concat!("// + 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")]
/// // ---------
#[doc = concat!("// 9 6 (sum = 9 × 2^", stringify!($BITS), " + 6)")]
///
#[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (3, ", stringify!($SelfT), "::MAX);")]
#[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
/// let carry0 = false;
///
/// let (sum0, carry1) = a0.carrying_add(b0, carry0);
/// assert_eq!(carry1, true);
/// let (sum1, carry2) = a1.carrying_add(b1, carry1);
/// assert_eq!(carry2, false);
///
/// assert_eq!((sum1, sum0), (9, 6));
/// ```
#[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
#[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
// note: longer-term this should be done via an intrinsic, but this has been shown
// to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
let (a, c1) = self.overflowing_add(rhs);
let (b, c2) = a.overflowing_add(carry as $SelfT);
// Ideally LLVM would know this is disjoint without us telling them,
// but it doesn't <https://github.com/llvm/llvm-project/issues/118162>
// SAFETY: Only one of `c1` and `c2` can be set.
// For c1 to be set we need to have overflowed, but if we did then
// `a` is at most `MAX-1`, which means that `c2` cannot possibly
// overflow because it's adding at most `1` (since it came from `bool`)
(b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
}
/// Calculates `self` + `rhs` with a signed `rhs`.
///
/// Returns a tuple of the addition along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")]
/// ```
#[stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
let (res, overflowed) = self.overflowing_add(rhs as Self);
(res, overflowed ^ (rhs < 0))
}
/// Calculates `self` - `rhs`.
///
/// Returns a tuple of the subtraction along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
(a as Self, b)
}
/// Calculates `self` &minus; `rhs` &minus; `borrow` and returns a tuple
/// containing the difference and the output borrow.
///
/// Performs "ternary subtraction" by subtracting both an integer
/// operand and a borrow-in bit from `self`, and returns an output
/// integer and a borrow-out bit. This allows chaining together multiple
/// subtractions to create a wider subtraction, and can be useful for
/// bignum subtraction.
///
/// # Examples
///
/// ```
#[doc = concat!("// 9 6 (a = 9 × 2^", stringify!($BITS), " + 6)")]
#[doc = concat!("// - 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")]
/// // ---------
#[doc = concat!("// 3 MAX (diff = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
///
#[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (9, 6);")]
#[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
/// let borrow0 = false;
///
/// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
/// assert_eq!(borrow1, true);
/// let (diff1, borrow2) = a1.borrowing_sub(b1, borrow1);
/// assert_eq!(borrow2, false);
///
#[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")]
/// ```
#[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
#[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
// note: longer-term this should be done via an intrinsic, but this has been shown
// to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
let (a, c1) = self.overflowing_sub(rhs);
let (b, c2) = a.overflowing_sub(borrow as $SelfT);
// SAFETY: Only one of `c1` and `c2` can be set.
// For c1 to be set we need to have underflowed, but if we did then
// `a` is nonzero, which means that `c2` cannot possibly
// underflow because it's subtracting at most `1` (since it came from `bool`)
(b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
}
/// Calculates `self` - `rhs` with a signed `rhs`
///
/// Returns a tuple of the subtraction along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(2), (", stringify!($SelfT), "::MAX, true));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(-2), (3, false));")]
#[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_sub_signed(-4), (1, true));")]
/// ```
#[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
#[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn overflowing_sub_signed(self, rhs: $SignedT) -> (Self, bool) {
let (res, overflow) = self.overflowing_sub(rhs as Self);
(res, overflow ^ (rhs < 0))
}
/// Computes the absolute difference between `self` and `other`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($SelfT), ");")]
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($SelfT), ");")]
/// ```
#[stable(feature = "int_abs_diff", since = "1.60.0")]
#[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn abs_diff(self, other: Self) -> Self {
if size_of::<Self>() == 1 {
// Trick LLVM into generating the psadbw instruction when SSE2
// is available and this function is autovectorized for u8's.
(self as i32).wrapping_sub(other as i32).unsigned_abs() as Self
} else {
if self < other {
other - self
} else {
self - other
}
}
}
/// 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.
///
/// If you want the *value* of the overflow, rather than just *whether*
/// an overflow occurred, see [`Self::carrying_mul`].
///
/// # Examples
///
/// Please note that this example is shared among integer types, which is why `u32` is used.
///
/// ```
/// assert_eq!(5u32.overflowing_mul(2), (10, false));
/// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
(a as Self, b)
}
/// Calculates the complete double-width product `self * rhs`.
///
/// This returns the low-order (wrapping) bits and the high-order (overflow) bits
/// of the result as two separate values, in that order. As such,
/// `a.widening_mul(b).0` produces the same result as `a.wrapping_mul(b)`.
///
/// If you also need to add a value and carry to the wide result, then you want
/// [`Self::carrying_mul_add`] instead.
///
/// If you also need to add a carry to the wide result, then you want
/// [`Self::carrying_mul`] instead.
///
/// If you just want to know *whether* the multiplication overflowed, then you
/// want [`Self::overflowing_mul`] instead.
///
/// # Examples
///
/// ```
/// #![feature(widening_mul)]
#[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".widening_mul(7), (35, 0));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.widening_mul(", stringify!($SelfT), "::MAX), (1, ", stringify!($SelfT), "::MAX - 1));")]
/// ```
///
/// Compared to other `*_mul` methods:
/// ```
/// #![feature(widening_mul)]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::widening_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), (0, 3));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::overflowing_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), (0, true));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::wrapping_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), 0);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::checked_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), None);")]
/// ```
///
/// Please note that this example is shared among integer types, which is why `u32` is used.
///
/// ```
/// #![feature(widening_mul)]
/// assert_eq!(5u32.widening_mul(2), (10, 0));
/// assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2));
/// ```
#[unstable(feature = "widening_mul", issue = "152016")]
#[rustc_const_unstable(feature = "widening_mul", issue = "152016")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn widening_mul(self, rhs: Self) -> (Self, Self) {
Self::carrying_mul_add(self, rhs, 0, 0)
}
/// Calculates the "full multiplication" `self * rhs + carry`
/// without the possibility to overflow.
///
/// This returns the low-order (wrapping) bits and the high-order (overflow) bits
/// of the result as two separate values, in that order.
///
/// Performs "long multiplication" which takes in an extra amount to add, and may return an
/// additional amount of overflow. This allows for chaining together multiple
/// multiplications to create "big integers" which represent larger values.
///
/// If you also need to add a value, then use [`Self::carrying_mul_add`].
///
/// # Examples
///
/// Please note that this example is shared among integer types, which is why `u32` is used.
///
/// ```
/// assert_eq!(5u32.carrying_mul(2, 0), (10, 0));
/// assert_eq!(5u32.carrying_mul(2, 10), (20, 0));
/// assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2));
/// assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2));
#[doc = concat!("assert_eq!(",
stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
"(0, ", stringify!($SelfT), "::MAX));"
)]
/// ```
///
/// This is the core operation needed for scalar multiplication when
/// implementing it for wider-than-native types.
///
/// ```
/// fn scalar_mul_eq(little_endian_digits: &mut Vec<u16>, multiplicand: u16) {
/// let mut carry = 0;
/// for d in little_endian_digits.iter_mut() {
/// (*d, carry) = d.carrying_mul(multiplicand, carry);
/// }
/// if carry != 0 {
/// little_endian_digits.push(carry);
/// }
/// }
///
/// let mut v = vec![10, 20];
/// scalar_mul_eq(&mut v, 3);
/// assert_eq!(v, [30, 60]);
///
/// assert_eq!(0x87654321_u64 * 0xFEED, 0x86D3D159E38D);
/// let mut v = vec![0x4321, 0x8765];
/// scalar_mul_eq(&mut v, 0xFEED);
/// assert_eq!(v, [0xE38D, 0xD159, 0x86D3]);
/// ```
///
/// If `carry` is zero, this is similar to [`overflowing_mul`](Self::overflowing_mul),
/// except that it gives the value of the overflow instead of just whether one happened:
///
/// ```
/// # #![allow(unused_features)]
/// #![feature(const_unsigned_bigint_helpers)]
/// let r = u8::carrying_mul(7, 13, 0);
/// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(7, 13));
/// let r = u8::carrying_mul(13, 42, 0);
/// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(13, 42));
/// ```
///
/// The value of the first field in the returned tuple matches what you'd get
/// by combining the [`wrapping_mul`](Self::wrapping_mul) and
/// [`wrapping_add`](Self::wrapping_add) methods:
///
/// ```
/// # #![allow(unused_features)]
/// #![feature(const_unsigned_bigint_helpers)]
/// assert_eq!(
/// 789_u16.carrying_mul(456, 123).0,
/// 789_u16.wrapping_mul(456).wrapping_add(123),
/// );
/// ```
#[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
#[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn carrying_mul(self, rhs: Self, carry: Self) -> (Self, Self) {
Self::carrying_mul_add(self, rhs, carry, 0)
}
/// Calculates the "full multiplication" `self * rhs + carry + add`.
///
/// This returns the low-order (wrapping) bits and the high-order (overflow) bits
/// of the result as two separate values, in that order.
///
/// This cannot overflow, as the double-width result has exactly enough
/// space for the largest possible result. This is equivalent to how, in
/// decimal, 9 × 9 + 9 + 9 = 81 + 18 = 99 = 9×10⁰ + 9×10¹ = 10² - 1.
///
/// 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 `add` part, then you can use [`Self::carrying_mul`] instead.
///
/// # Examples
///
/// Please note that this example is shared between integer types,
/// which explains why `u32` is used here.
///
/// ```
/// assert_eq!(5u32.carrying_mul_add(2, 0, 0), (10, 0));
/// assert_eq!(5u32.carrying_mul_add(2, 10, 10), (30, 0));
/// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 0, 0), (1410065408, 2));
/// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 10, 10), (1410065428, 2));
#[doc = concat!("assert_eq!(",
stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
"(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX));"
)]
/// ```
///
/// This is the core per-digit operation for "grade school" O(n²) multiplication.
///
/// Please note that this example is shared between integer types,
/// using `u8` for simplicity of the demonstration.
///
/// ```
/// fn quadratic_mul<const N: usize>(a: [u8; N], b: [u8; N]) -> [u8; N] {
/// let mut out = [0; N];
/// for j in 0..N {
/// let mut carry = 0;
/// for i in 0..(N - j) {
/// (out[j + i], carry) = u8::carrying_mul_add(a[i], b[j], out[j + i], carry);
/// }
/// }
/// out
/// }
///
/// // -1 * -1 == 1
/// assert_eq!(quadratic_mul([0xFF; 3], [0xFF; 3]), [1, 0, 0]);
///
/// assert_eq!(u32::wrapping_mul(0x9e3779b9, 0x7f4a7c15), 0xcffc982d);
/// assert_eq!(
/// quadratic_mul(u32::to_le_bytes(0x9e3779b9), u32::to_le_bytes(0x7f4a7c15)),
/// u32::to_le_bytes(0xcffc982d)
/// );
/// ```
#[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
#[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> (Self, Self) {
intrinsics::carrying_mul_add(self, rhs, carry, add)
}
/// Calculates the divisor when `self` is divided by `rhs`.
///
/// Returns a tuple of the divisor along with a boolean indicating
/// whether an arithmetic overflow would occur. Note that for unsigned
/// integers overflow never occurs, so the second value is always
/// `false`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
/// ```
#[inline(always)]
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[track_caller]
pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
(self / rhs, false)
}
/// 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. Note that for unsigned
/// integers overflow never occurs, so the second value is always
/// `false`.
/// Since, for the positive integers, all common
/// definitions of division are equal, this
/// is exactly equal to `self.overflowing_div(rhs)`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
/// ```
#[inline(always)]
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[track_caller]
pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
(self / rhs, false)
}
/// Calculates the remainder when `self` is divided by `rhs`.
///
/// Returns a tuple of the remainder after dividing along with a boolean
/// indicating whether an arithmetic overflow would occur. Note that for
/// unsigned integers overflow never occurs, so the second value is
/// always `false`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
/// ```
#[inline(always)]
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[track_caller]
pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
(self % rhs, false)
}
/// Calculates the remainder `self.rem_euclid(rhs)` as if by Euclidean division.
///
/// Returns a tuple of the modulo after dividing along with a boolean
/// indicating whether an arithmetic overflow would occur. Note that for
/// unsigned integers overflow never occurs, so the second value is
/// always `false`.
/// Since, for the positive integers, all common
/// definitions of division are equal, this operation
/// is exactly equal to `self.overflowing_rem(rhs)`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
/// ```
#[inline(always)]
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[track_caller]
pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
(self % rhs, false)
}
/// Negates self in an overflowing fashion.
///
/// Returns `!self + 1` using wrapping operations to return the value
/// that represents the negation of this unsigned value. Note that for
/// positive unsigned values overflow always occurs, but negating 0 does
/// not overflow.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false));")]
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), ", true));")]
/// ```
#[inline(always)]
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_neg(self) -> (Self, bool) {
((!self).wrapping_add(1), self != 0)
}
/// 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
///
/// ```
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")]
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shl(rhs), rhs >= Self::BITS)
}
/// 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
///
/// ```
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shr(rhs), rhs >= Self::BITS)
}
/// 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
///
/// ```
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")]
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".overflowing_pow(0), (1, false));")]
/// assert_eq!(3u8.overflowing_pow(6), (217, true));
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
if exp == 0{
return (1,false);
}
let mut base = self;
let mut acc: Self = 1;
let mut overflown = false;
// Scratch space for storing results of overflowing_mul.
let mut r;
loop {
if (exp & 1) == 1 {
r = acc.overflowing_mul(base);
// since exp!=0, finally the exp must be 1.
if exp == 1 {
r.1 |= overflown;
return r;
}
acc = r.0;
overflown |= r.1;
}
exp /= 2;
r = base.overflowing_mul(base);
base = r.0;
overflown |= r.1;
}
}
/// Raises self to the power of `exp`, using exponentiation by squaring.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")]
#[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".pow(0), 1);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn pow(self, mut exp: u32) -> Self {
if exp == 0 {
return 1;
}
let mut base = self;
let mut acc = 1;
if intrinsics::is_val_statically_known(exp) {
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp /= 2;
base = base * base;
}
// since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
acc * base
} else {
// This is faster than the above when the exponent is not known
// at compile time. We can't use the same code for the constant
// exponent case because LLVM is currently unable to unroll
// this loop.
loop {
if (exp & 1) == 1 {
acc = acc * base;
// since exp!=0, finally the exp must be 1.
if exp == 1 {
return acc;
}
}
exp /= 2;
base = base * base;
}
}
}
/// Returns the square root of the number, rounded down.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
/// ```
#[stable(feature = "isqrt", since = "1.84.0")]
#[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn isqrt(self) -> Self {
let result = imp::int_sqrt::$ActualT(self as $ActualT) as $SelfT;
// Inform the optimizer what the range of outputs is. If testing
// `core` crashes with no panic message and a `num::int_sqrt::u*`
// test failed, it's because your edits caused these assertions or
// the assertions in `fn isqrt` of `nonzero.rs` to become false.
//
// SAFETY: Integer square root is a monotonically nondecreasing
// function, which means that increasing the input will never
// cause the output to decrease. Thus, since the input for unsigned
// integers is bounded by `[0, <$ActualT>::MAX]`, sqrt(n) will be
// bounded by `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
unsafe {
const MAX_RESULT: $SelfT = imp::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT;
crate::hint::assert_unchecked(result <= MAX_RESULT);
}
result
}
/// Performs Euclidean division.
///
/// Since, for the positive integers, all common
/// definitions of division are equal, this
/// is exactly equal to `self / rhs`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn div_euclid(self, rhs: Self) -> Self {
self / rhs
}
/// Calculates the least remainder of `self` when divided by
/// `rhs`.
///
/// Since, for the positive integers, all common
/// definitions of division are equal, this
/// is exactly equal to `self % rhs`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type")]
/// ```
#[doc(alias = "modulo", alias = "mod")]
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn rem_euclid(self, rhs: Self) -> Self {
self % rhs
}
/// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
///
/// This is the same as performing `self / rhs` for all unsigned integers.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
/// #![feature(int_roundings)]
#[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")]
/// ```
#[unstable(feature = "int_roundings", issue = "88581")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[track_caller]
pub const fn div_floor(self, rhs: Self) -> Self {
self / rhs
}
/// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")]
/// ```
#[stable(feature = "int_roundings1", since = "1.73.0")]
#[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
pub const fn div_ceil(self, rhs: Self) -> Self {
let d = self / rhs;
let r = self % rhs;
if r > 0 {
d + 1
} else {
d
}
}
/// Calculates the smallest value greater than or equal to `self` that
/// is a multiple of `rhs`.
///
/// # Panics
///
/// This function will panic if `rhs` is zero.
///
/// ## Overflow behavior
///
/// On overflow, this function will panic if overflow checks are enabled (default in debug
/// mode) and wrap if overflow checks are disabled (default in release mode).
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
#[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
/// ```
#[stable(feature = "int_roundings1", since = "1.73.0")]
#[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn next_multiple_of(self, rhs: Self) -> Self {
match self % rhs {
0 => self,
r => self + (rhs - r)
}
}
/// Calculates the smallest value greater than or equal to `self` that
/// is a multiple of `rhs`. Returns `None` if `rhs` is zero or the
/// operation would result in overflow.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
#[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
#[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
/// ```
#[stable(feature = "int_roundings1", since = "1.73.0")]
#[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
match try_opt!(self.checked_rem(rhs)) {
0 => Some(self),
// rhs - r cannot overflow because r is smaller than rhs
r => self.checked_add(rhs - r)
}
}
/// Returns `true` if `self` is an integer multiple of `rhs`, and false otherwise.
///
/// This function is equivalent to `self % rhs == 0`, except that it will not panic
/// for `rhs == 0`. Instead, `0.is_multiple_of(0) == true`, and for any non-zero `n`,
/// `n.is_multiple_of(0) == false`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert!(6_", stringify!($SelfT), ".is_multiple_of(2));")]
#[doc = concat!("assert!(!5_", stringify!($SelfT), ".is_multiple_of(2));")]
///
#[doc = concat!("assert!(0_", stringify!($SelfT), ".is_multiple_of(0));")]
#[doc = concat!("assert!(!6_", stringify!($SelfT), ".is_multiple_of(0));")]
/// ```
#[stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
#[rustc_const_stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
#[must_use]
#[inline]
pub const fn is_multiple_of(self, rhs: Self) -> bool {
match rhs {
0 => self == 0,
_ => self % rhs == 0,
}
}
/// Returns `true` if and only if `self == 2^k` for some unsigned integer `k`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert!(16", stringify!($SelfT), ".is_power_of_two());")]
#[doc = concat!("assert!(!10", stringify!($SelfT), ".is_power_of_two());")]
/// ```
#[must_use]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")]
#[inline(always)]
pub const fn is_power_of_two(self) -> bool {
self.count_ones() == 1
}
// Returns one less than next power of two.
// (For 8u8 next power of two is 8u8 and for 6u8 it is 8u8)
//
// 8u8.one_less_than_next_power_of_two() == 7
// 6u8.one_less_than_next_power_of_two() == 7
//
// This method cannot overflow, as in the `next_power_of_two`
// overflow cases it instead ends up returning the maximum value
// of the type, and can return 0 for 0.
#[inline]
const fn one_less_than_next_power_of_two(self) -> Self {
if self <= 1 { return 0; }
let p = self - 1;
// SAFETY: Because `p > 0`, it cannot consist entirely of leading zeros.
// That means the shift is always in-bounds, and some processors
// (such as intel pre-haswell) have more efficient ctlz
// intrinsics when the argument is non-zero.
let z = unsafe { intrinsics::ctlz_nonzero(p) };
<$SelfT>::MAX >> z
}
/// Returns the smallest power of two greater than or equal to `self`.
///
/// When return value overflows (i.e., `self > (1 << (N-1))` for type
/// `uN`), it panics in debug mode and the return value is wrapped to 0 in
/// release mode (the only situation in which this method can return 0).
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")]
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")]
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".next_power_of_two(), 1);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn next_power_of_two(self) -> Self {
self.one_less_than_next_power_of_two() + 1
}
/// Returns the smallest power of two greater than or equal to `self`. If
/// the next power of two is greater than the type's maximum value,
/// `None` is returned, otherwise the power of two is wrapped in `Some`.
///
/// # Examples
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_next_power_of_two(), Some(2));")]
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);")]
/// ```
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn checked_next_power_of_two(self) -> Option<Self> {
self.one_less_than_next_power_of_two().checked_add(1)
}
/// Returns the smallest power of two greater than or equal to `n`. If
/// the next power of two is greater than the type's maximum value,
/// the return value is wrapped to `0`.
///
/// # Examples
///
/// ```
/// #![feature(wrapping_next_power_of_two)]
///
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);")]
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);")]
/// ```
#[inline]
#[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
reason = "needs decision on wrapping behavior")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn wrapping_next_power_of_two(self) -> Self {
self.one_less_than_next_power_of_two().wrapping_add(1)
}
/// Returns the memory representation of this integer as a byte array in
/// big-endian (network) byte order.
///
#[doc = $to_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
#[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] {
self.to_be().to_ne_bytes()
}
/// Returns the memory representation of this integer as a byte array in
/// little-endian byte order.
///
#[doc = $to_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
#[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] {
self.to_le().to_ne_bytes()
}
/// 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.
///
#[doc = $to_xe_bytes_doc]
///
/// [`to_be_bytes`]: Self::to_be_bytes
/// [`to_le_bytes`]: Self::to_le_bytes
///
/// # Examples
///
/// ```
#[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
/// assert_eq!(
/// bytes,
/// if cfg!(target_endian = "big") {
#[doc = concat!(" ", $be_bytes)]
/// } else {
#[doc = concat!(" ", $le_bytes)]
/// }
/// );
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[allow(unnecessary_transmutes)]
// SAFETY: const sound because integers are plain old datatypes so we can always
// transmute them to arrays of bytes
#[inline]
pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] {
// SAFETY: integers are plain old datatypes so we can always transmute them to
// arrays of bytes
unsafe { mem::transmute(self) }
}
/// Creates a native endian integer value from its representation
/// as a byte array in big endian.
///
#[doc = $from_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
#[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
/// ```
///
/// When starting from a slice rather than an array, fallible conversion APIs can be used:
///
/// ```
#[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
/// *input = rest;
#[doc = concat!(" ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
/// }
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use]
#[inline]
pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
Self::from_be(Self::from_ne_bytes(bytes))
}
/// Creates a native endian integer value from its representation
/// as a byte array in little endian.
///
#[doc = $from_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
#[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
/// ```
///
/// When starting from a slice rather than an array, fallible conversion APIs can be used:
///
/// ```
#[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
/// *input = rest;
#[doc = concat!(" ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
/// }
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use]
#[inline]
pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
Self::from_le(Self::from_ne_bytes(bytes))
}
/// Creates a native endian integer value from its memory representation
/// as a byte array in native endianness.
///
/// As the target platform's native endianness is used, portable code
/// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
/// appropriate instead.
///
/// [`from_be_bytes`]: Self::from_be_bytes
/// [`from_le_bytes`]: Self::from_le_bytes
///
#[doc = $from_xe_bytes_doc]
///
/// # Examples
///
/// ```
#[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
#[doc = concat!(" ", $be_bytes, "")]
/// } else {
#[doc = concat!(" ", $le_bytes, "")]
/// });
#[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
/// ```
///
/// When starting from a slice rather than an array, fallible conversion APIs can be used:
///
/// ```
#[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
/// *input = rest;
#[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
/// }
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[allow(unnecessary_transmutes)]
#[must_use]
// SAFETY: const sound because integers are plain old datatypes so we can always
// transmute to them
#[inline]
pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
// SAFETY: integers are plain old datatypes so we can always transmute to them
unsafe { mem::transmute(bytes) }
}
/// New code should prefer to use
#[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
///
/// Returns the smallest value that can be represented by this integer type.
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_promotable]
#[inline(always)]
#[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
#[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
#[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
pub const fn min_value() -> Self { Self::MIN }
/// New code should prefer to use
#[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
///
/// Returns the largest value that can be represented by this integer type.
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_promotable]
#[inline(always)]
#[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
#[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
#[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
pub const fn max_value() -> Self { Self::MAX }
}
}