Google Git
Sign in
android / toolchain / rustc / 2805eef6921176b3ba92a12d4ab81b6462584a1c / . / library / core / src / num / uint_macros.rs
blob: feec448ebbdb318e687386ef772b49bdd579e1b9 [file] [log] [blame]
macro_rules! uint_impl {
($SelfT:ty, $ActualT:ident, $SignedT:ident, $NonZeroT:ident,
$BITS:expr, $MaxV:expr,
$rot:expr, $rot_op:expr, $rot_result:expr, $swap_op:expr, $swapped:expr,
$reversed:expr, $le_bytes:expr, $be_bytes:expr,
$to_xe_bytes_doc:expr, $from_xe_bytes_doc:expr) => {
/// The smallest value that can be represented by this integer type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($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>", $BITS, "</sup> &minus; 1.")]
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($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 = $BITS;
/// Converts a string slice in a given base to an integer.
///
/// The string is expected to be an optional `+` sign
/// followed by digits.
/// Leading and trailing whitespace represent an error.
/// Digits are a subset of these characters, depending on `radix`:
///
/// * `0-9`
/// * `a-z`
/// * `A-Z`
///
/// # Panics
///
/// This function panics if `radix` is not in the range from 2 to 36.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::from_str_radix(\"A\", 16), Ok(10));")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> {
from_str_radix(src, radix)
}
/// Returns the number of ones in the binary representation of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")]
///
/// assert_eq!(n.count_ones(), 3);
/// ```
#[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 {
intrinsics::ctpop(self as $ActualT) as u32
}
/// Returns the number of zeros in the binary representation of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.count_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 count_zeros(self) -> u32 {
(!self).count_ones()
}
/// Returns the number of leading zeros in the binary representation of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")]
///
/// assert_eq!(n.leading_zeros(), 2);
/// ```
#[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 {
intrinsics::ctlz(self as $ActualT) as u32
}
/// Returns the number of trailing zeros in the binary representation
/// of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")]
///
/// assert_eq!(n.trailing_zeros(), 3);
/// ```
#[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 {
intrinsics::cttz(self) as u32
}
/// Returns the number of leading ones in the binary representation of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")]
///
/// assert_eq!(n.leading_ones(), 2);
/// ```
#[stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn leading_ones(self) -> u32 {
(!self).leading_zeros()
}
/// Returns the number of trailing ones in the binary representation
/// of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")]
///
/// assert_eq!(n.trailing_ones(), 3);
/// ```
#[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()
}
/// Shifts the bits to the left by a specified amount, `n`,
/// wrapping the truncated bits to the end of the resulting integer.
///
/// Please note this isn't the same operation as the `<<` shifting operator!
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
#[doc = concat!("let m = ", $rot_result, ";")]
///
#[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
/// ```
#[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 rotate_left(self, n: u32) -> Self {
intrinsics::rotate_left(self, n as $SelfT)
}
/// Shifts the bits to the right by a specified amount, `n`,
/// wrapping the truncated bits to the beginning of the resulting
/// integer.
///
/// Please note this isn't the same operation as the `>>` shifting operator!
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
#[doc = concat!("let m = ", $rot_op, ";")]
///
#[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
/// ```
#[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 rotate_right(self, n: u32) -> Self {
intrinsics::rotate_right(self, n as $SelfT)
}
/// Reverses the byte order of the integer.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[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
}
/// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
/// second least-significant bit becomes second most-significant bit, etc.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[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 = "const_math", 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 $ActualT) as Self
}
/// Converts an integer from big endian to the target's endianness.
///
/// On big endian this is a no-op. On little endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($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
///
/// Basic usage:
///
/// ```
#[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!($SelfT), "::from_le(n), n.swap_bytes())")]
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use]
#[inline(always)]
pub const fn from_le(x: Self) -> Self {
#[cfg(target_endian = "little")]
{
x
}
#[cfg(not(target_endian = "little"))]
{
x.swap_bytes()
}
}
/// Converts `self` to big endian from the target's endianness.
///
/// On big endian this is a no-op. On little endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($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
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
///
/// if cfg!(target_endian = "little") {
/// assert_eq!(n.to_le(), n)
/// } else {
/// assert_eq!(n.to_le(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn to_le(self) -> Self {
#[cfg(target_endian = "little")]
{
self
}
#[cfg(not(target_endian = "little"))]
{
self.swap_bytes()
}
}
/// Checked integer addition. Computes `self + rhs`, returning `None`
/// if overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!(
"assert_eq!((", stringify!($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> {
let (a, b) = self.overflowing_add(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// Unchecked integer addition. Computes `self + rhs`, assuming overflow
/// cannot occur.
///
/// # 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`.
///
#[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
// SAFETY: the caller must uphold the safety contract for
// `unchecked_add`.
unsafe { intrinsics::unchecked_add(self, rhs) }
}
/// Checked addition with a signed integer. Computes `self + rhs`,
/// returning `None` if overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// # #![feature(mixed_integer_ops)]
#[doc = concat!("assert_eq!(1", stringify!($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);")]
/// ```
#[unstable(feature = "mixed_integer_ops", issue = "87840")]
#[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
let (a, b) = self.overflowing_add_signed(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// Checked integer subtraction. Computes `self - rhs`, returning
/// `None` if overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")]
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_sub(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
/// cannot occur.
///
/// # Safety
///
/// This results in undefined behavior when
#[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
/// i.e. when [`checked_sub`] would return `None`.
///
#[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
// SAFETY: the caller must uphold the safety contract for
// `unchecked_sub`.
unsafe { intrinsics::unchecked_sub(self, rhs) }
}
/// Checked integer multiplication. Computes `self * rhs`, returning
/// `None` if overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[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 unlikely!(b) {None} else {Some(a)}
}
/// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
/// cannot occur.
///
/// # 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`.
///
#[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
// SAFETY: the caller must uphold the safety contract for
// `unchecked_mul`.
unsafe { intrinsics::unchecked_mul(self, rhs) }
}
/// Checked integer division. Computes `self / rhs`, returning `None`
/// if `rhs == 0`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_div(self, rhs: Self) -> Option<Self> {
if unlikely!(rhs == 0) {
None
} else {
// SAFETY: div by zero has been checked above and unsigned types have no other
// failure modes for division
Some(unsafe { intrinsics::unchecked_div(self, rhs) })
}
}
/// Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None`
/// if `rhs == 0`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
if unlikely!(rhs == 0) {
None
} else {
Some(self.div_euclid(rhs))
}
}
/// Checked integer remainder. Computes `self % rhs`, returning `None`
/// if `rhs == 0`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
if unlikely!(rhs == 0) {
None
} else {
// SAFETY: div by zero has been checked above and unsigned types have no other
// failure modes for division
Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
}
}
/// Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None`
/// if `rhs == 0`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
if unlikely!(rhs == 0) {
None
} else {
Some(self.rem_euclid(rhs))
}
}
/// Returns the logarithm of the number with respect to an arbitrary base,
/// rounded down.
///
/// This method might not be optimized owing to implementation details;
/// `log2` can produce results more efficiently for base 2, and `log10`
/// can produce results more efficiently for base 10.
///
/// # Panics
///
/// When the number is negative, zero, or if the base is not at least 2;
/// it panics in debug mode and the return value is 0 in release mode.
///
/// # Examples
///
/// ```
/// #![feature(int_log)]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".log(5), 1);")]
/// ```
#[unstable(feature = "int_log", issue = "70887")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
#[rustc_inherit_overflow_checks]
#[allow(arithmetic_overflow)]
pub const fn log(self, base: Self) -> u32 {
match self.checked_log(base) {
Some(n) => n,
None => {
// In debug builds, trigger a panic on None.
// This should optimize completely out in release builds.
let _ = Self::MAX + 1;
0
},
}
}
/// Returns the base 2 logarithm of the number, rounded down.
///
/// # Panics
///
/// When the number is negative or zero it panics in debug mode and
/// the return value is 0 in release mode.
///
/// # Examples
///
/// ```
/// #![feature(int_log)]
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".log2(), 1);")]
/// ```
#[unstable(feature = "int_log", issue = "70887")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
#[rustc_inherit_overflow_checks]
#[allow(arithmetic_overflow)]
pub const fn log2(self) -> u32 {
match self.checked_log2() {
Some(n) => n,
None => {
// In debug builds, trigger a panic on None.
// This should optimize completely out in release builds.
let _ = Self::MAX + 1;
0
},
}
}
/// Returns the base 10 logarithm of the number, rounded down.
///
/// # Panics
///
/// When the number is negative or zero it panics in debug mode and the
/// return value is 0 in release mode.
///
/// # Example
///
/// ```
/// #![feature(int_log)]
#[doc = concat!("assert_eq!(10", stringify!($SelfT), ".log10(), 1);")]
/// ```
#[unstable(feature = "int_log", issue = "70887")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[track_caller]
#[rustc_inherit_overflow_checks]
#[allow(arithmetic_overflow)]
pub const fn log10(self) -> u32 {
match self.checked_log10() {
Some(n) => n,
None => {
// In debug builds, trigger a panic on None.
// This should optimize completely out in release builds.
let _ = Self::MAX + 1;
0
},
}
}
/// 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_log2` can produce results more efficiently for base 2, and
/// `checked_log10` can produce results more efficiently for base 10.
///
/// # Examples
///
/// ```
/// #![feature(int_log)]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_log(5), Some(1));")]
/// ```
#[unstable(feature = "int_log", issue = "70887")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_log(self, base: Self) -> Option<u32> {
if self <= 0 || base <= 1 {
None
} else {
let mut n = 0;
let mut r = self;
// Optimization for 128 bit wide integers.
if Self::BITS == 128 {
let b = Self::log2(self) / (Self::log2(base) + 1);
n += b;
r /= base.pow(b as u32);
}
while r >= base {
r /= base;
n += 1;
}
Some(n)
}
}
/// Returns the base 2 logarithm of the number, rounded down.
///
/// Returns `None` if the number is zero.
///
/// # Examples
///
/// ```
/// #![feature(int_log)]
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_log2(), Some(1));")]
/// ```
#[unstable(feature = "int_log", issue = "70887")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_log2(self) -> Option<u32> {
if let Some(x) = <$NonZeroT>::new(self) {
Some(x.log2())
} else {
None
}
}
/// Returns the base 10 logarithm of the number, rounded down.
///
/// Returns `None` if the number is zero.
///
/// # Examples
///
/// ```
/// #![feature(int_log)]
#[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_log10(), Some(1));")]
/// ```
#[unstable(feature = "int_log", issue = "70887")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_log10(self) -> Option<u32> {
if let Some(x) = <$NonZeroT>::new(self) {
Some(x.log10())
} else {
None
}
}
/// Checked negation. Computes `-self`, returning `None` unless `self ==
/// 0`.
///
/// Note that negating any positive integer will overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_neg(self) -> Option<Self> {
let (a, b) = self.overflowing_neg();
if unlikely!(b) {None} else {Some(a)}
}
/// Checked shift left. Computes `self << rhs`, returning `None`
/// if `rhs` is larger than or equal to the number of bits in `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shl(rhs);
if unlikely!(b) {None} else {Some(a)}
}
/// Unchecked shift left. Computes `self << rhs`, assuming that
/// `rhs` is less than the number of bits in `self`.
///
/// # Safety
///
/// This results in undefined behavior if `rhs` is larger than
/// or equal to the number of bits in `self`,
/// i.e. when [`checked_shl`] would return `None`.
///
#[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
pub const unsafe fn unchecked_shl(self, rhs: Self) -> Self {
// SAFETY: the caller must uphold the safety contract for
// `unchecked_shl`.
unsafe { intrinsics::unchecked_shl(self, rhs) }
}
/// Checked shift right. Computes `self >> rhs`, returning `None`
/// if `rhs` is larger than or equal to the number of bits in `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[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> {
let (a, b) = self.overflowing_shr(rhs);
if unlikely!(b) {None} else {Some(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!($SelfT), "::checked_shr")]
#[unstable(
feature = "unchecked_math",
reason = "niche optimization path",
issue = "85122",
)]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_unstable(feature = "const_inherent_unchecked_arith", issue = "85122")]
#[inline(always)]
pub const unsafe fn unchecked_shr(self, rhs: Self) -> Self {
// SAFETY: the caller must uphold the safety contract for
// `unchecked_shr`.
unsafe { intrinsics::unchecked_shr(self, rhs) }
}
/// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
/// overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
if exp == 0 {
return Some(1);
}
let mut base = self;
let mut acc: Self = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = try_opt!(acc.checked_mul(base));
}
exp /= 2;
base = try_opt!(base.checked_mul(base));
}
// since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
Some(try_opt!(acc.checked_mul(base)))
}
/// Saturating integer addition. Computes `self + rhs`, saturating at
/// the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($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
///
/// Basic usage:
///
/// ```
/// # #![feature(mixed_integer_ops)]
#[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);")]
/// ```
#[unstable(feature = "mixed_integer_ops", issue = "87840")]
#[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
let (res, overflow) = self.overflowing_add(rhs as Self);
if overflow == (rhs < 0) {
res
} else if overflow {
Self::MAX
} else {
0
}
}
/// Saturating integer subtraction. Computes `self - rhs`, saturating
/// at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")]
#[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
#[inline(always)]
pub const fn saturating_sub(self, rhs: Self) -> Self {
intrinsics::saturating_sub(self, rhs)
}
/// Saturating integer multiplication. Computes `self * rhs`,
/// saturating at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($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.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
///
/// ```
///
/// ```should_panic
#[doc = concat!("let _ = 1", stringify!($SelfT), ".saturating_div(0);")]
///
/// ```
#[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]
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
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_pow(self, exp: u32) -> Self {
match self.checked_pow(exp) {
Some(x) => x,
None => Self::MAX,
}
}
/// Wrapping (modular) addition. Computes `self + rhs`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(200", stringify!($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
///
/// Basic usage:
///
/// ```
/// # #![feature(mixed_integer_ops)]
#[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);")]
/// ```
#[unstable(feature = "mixed_integer_ops", issue = "87840")]
#[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self {
self.wrapping_add(rhs as Self)
}
/// Wrapping (modular) subtraction. Computes `self - rhs`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($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) multiplication. Computes `self *
/// rhs`, wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// Please note that this example is shared between integer types.
/// Which explains why `u8` is used here.
///
/// ```
/// 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.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_div(self, rhs: Self) -> Self {
self / rhs
}
/// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`.
/// Wrapped division on unsigned types is just normal division.
/// There's no way wrapping could ever happen.
/// This function exists, so that all operations
/// are accounted for in the wrapping operations.
/// Since, for the positive integers, all common
/// definitions of division are equal, this
/// is exactly equal to `self.wrapping_div(rhs)`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($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)]
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.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_rem(self, rhs: Self) -> Self {
self % rhs
}
/// Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`.
/// Wrapped modulo calculation on unsigned types is
/// just the regular remainder calculation.
/// There's no way wrapping could ever happen.
/// This function exists, so that all operations
/// are accounted for in the wrapping operations.
/// Since, for the positive integers, all common
/// definitions of division are equal, this
/// is exactly equal to `self.wrapping_rem(rhs)`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($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)]
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
///
/// Basic usage:
///
/// Please note that this example is shared between integer types.
/// Which explains why `i8` is used here.
///
/// ```
/// assert_eq!(100i8.wrapping_neg(), -100);
/// assert_eq!((-128i8).wrapping_neg(), -128);
/// ```
#[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 $SelfT).wrapping_sub(self)
}
/// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
/// where `mask` removes any high-order bits of `rhs` that
/// would cause the shift to exceed the bitwidth of the type.
///
/// Note that this is *not* the same as a rotate-left; the
/// RHS of a wrapping shift-left is restricted to the range
/// of the type, rather than the bits shifted out of the LHS
/// being returned to the other end. The primitive integer
/// types all implement a [`rotate_left`](Self::rotate_left) function,
/// which may be what you want instead.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(7), 128);")]
#[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(128), 1);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_shl(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
intrinsics::unchecked_shl(self, (rhs & ($BITS - 1)) as $SelfT)
}
}
/// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
/// where `mask` removes any high-order bits of `rhs` that
/// would cause the shift to exceed the bitwidth of the type.
///
/// Note that this is *not* the same as a rotate-right; the
/// RHS of a wrapping shift-right is restricted to the range
/// of the type, rather than the bits shifted out of the LHS
/// being returned to the other end. The primitive integer
/// types all implement a [`rotate_right`](Self::rotate_right) function,
/// which may be what you want instead.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(7), 1);")]
#[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(128), 128);")]
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn wrapping_shr(self, rhs: u32) -> Self {
// SAFETY: the masking by the bitsize of the type ensures that we do not shift
// out of bounds
unsafe {
intrinsics::unchecked_shr(self, (rhs & ($BITS - 1)) as $SelfT)
}
}
/// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")]
/// assert_eq!(3u8.wrapping_pow(6), 217);
/// ```
#[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;
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 and may cause a
// needless overflow.
acc.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
///
/// Basic usage
///
/// ```
///
#[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 $ActualT);
(a as Self, b)
}
/// Calculates `self + rhs + carry` without the ability to overflow.
///
/// Performs "ternary addition" which takes in an extra bit to add, and may return an
/// additional bit of overflow. This allows for chaining together multiple additions
/// to create "big integers" which represent larger values.
///
#[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit \"full adder\", in the electronics sense.")]
///
/// # Examples
///
/// Basic usage
///
/// ```
/// #![feature(bigint_helper_methods)]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".carrying_add(2, false), (7, false));")]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".carrying_add(2, true), (8, false));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, false), (0, true));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(0, true), (0, true));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, true), (1, true));")]
#[doc = concat!("assert_eq!(",
stringify!($SelfT), "::MAX.carrying_add(", stringify!($SelfT), "::MAX, true), ",
"(", stringify!($SelfT), "::MAX, true));"
)]
/// ```
///
/// If `carry` is false, this method is equivalent to [`overflowing_add`](Self::overflowing_add):
///
/// ```
/// #![feature(bigint_helper_methods)]
#[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".carrying_add(2, false), 5_", stringify!($SelfT), ".overflowing_add(2));")]
#[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.carrying_add(1, false), ", stringify!($SelfT), "::MAX.overflowing_add(1));")]
/// ```
#[unstable(feature = "bigint_helper_methods", issue = "85532")]
#[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")]
#[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, b) = self.overflowing_add(rhs);
let (c, d) = a.overflowing_add(carry as $SelfT);
(c, b || d)
}
/// Calculates `self` + `rhs` with a signed `rhs`
///
/// Returns a tuple of the addition along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// # #![feature(mixed_integer_ops)]
#[doc = concat!("assert_eq!(1", stringify!($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));")]
/// ```
#[unstable(feature = "mixed_integer_ops", issue = "87840")]
#[rustc_const_unstable(feature = "mixed_integer_ops", issue = "87840")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
let (res, overflowed) = self.overflowing_add(rhs as Self);
(res, overflowed ^ (rhs < 0))
}
/// Calculates `self` - `rhs`
///
/// Returns a tuple of the subtraction along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// Basic usage
///
/// ```
///
#[doc = concat!("assert_eq!(5", stringify!($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 $ActualT);
(a as Self, b)
}
/// Calculates `self - rhs - borrow` without the ability to overflow.
///
/// Performs "ternary subtraction" which takes in an extra bit to subtract, and may return
/// an additional bit of overflow. This allows for chaining together multiple subtractions
/// to create "big integers" which represent larger values.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// #![feature(bigint_helper_methods)]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".borrowing_sub(2, false), (3, false));")]
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".borrowing_sub(2, true), (2, false));")]
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".borrowing_sub(1, false), (", stringify!($SelfT), "::MAX, true));")]
#[doc = concat!("assert_eq!(0", stringify!($SelfT), ".borrowing_sub(1, true), (", stringify!($SelfT), "::MAX - 1, true));")]
/// ```
#[unstable(feature = "bigint_helper_methods", issue = "85532")]
#[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")]
#[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, b) = self.overflowing_sub(rhs);
let (c, d) = a.overflowing_sub(borrow as $SelfT);
(c, b || d)
}
/// Computes the absolute difference between `self` and `other`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(100", stringify!($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 mem::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).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.
///
/// # Examples
///
/// Basic usage:
///
/// Please note that this example is shared between integer types.
/// Which explains why `u32` is used here.
///
/// ```
/// 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 $ActualT);
(a as Self, b)
}
/// Calculates the divisor when `self` is divided by `rhs`.
///
/// Returns a tuple of the divisor along with a boolean indicating
/// whether an arithmetic overflow would occur. Note that for unsigned
/// integers overflow never occurs, so the second value is always
/// `false`.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($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"]
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 0.
///
/// # Examples
///
/// Basic usage
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
/// ```
#[inline(always)]
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
(self / rhs, false)
}
/// Calculates the remainder when `self` is divided by `rhs`.
///
/// Returns a tuple of the remainder after dividing along with a boolean
/// indicating whether an arithmetic overflow would occur. Note that for
/// unsigned integers overflow never occurs, so the second value is
/// always `false`.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($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"]
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 0.
///
/// # Examples
///
/// Basic usage
///
/// ```
#[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
/// ```
#[inline(always)]
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
(self % rhs, false)
}
/// Negates self in an overflowing fashion.
///
/// Returns `!self + 1` using wrapping operations to return the value
/// that represents the negation of this unsigned value. Note that for
/// positive unsigned values overflow always occurs, but negating 0 does
/// not overflow.
///
/// # Examples
///
/// Basic usage
///
/// ```
#[doc = concat!("assert_eq!(0", stringify!($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
///
/// Basic usage
///
/// ```
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")]
#[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, 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_shl(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shl(rhs), (rhs > ($BITS - 1)))
}
/// Shifts self right by `rhs` bits.
///
/// Returns a tuple of the shifted version of self along with a boolean
/// indicating whether the shift value was larger than or equal to the
/// number of bits. If the shift value is too large, then value is
/// masked (N-1) where N is the number of bits, and this value is then
/// used to perform the shift.
///
/// # Examples
///
/// Basic usage
///
/// ```
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
#[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));")]
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
(self.wrapping_shr(rhs), (rhs > ($BITS - 1)))
}
/// Raises self to the power of `exp`, using exponentiation by squaring.
///
/// Returns a tuple of the exponentiation along with a bool indicating
/// whether an overflow happened.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")]
/// assert_eq!(3u8.overflowing_pow(6), (217, true));
/// ```
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
if exp == 0{
return (1,false);
}
let mut base = self;
let mut acc: Self = 1;
let mut overflown = false;
// Scratch space for storing results of overflowing_mul.
let mut r;
while exp > 1 {
if (exp & 1) == 1 {
r = acc.overflowing_mul(base);
acc = r.0;
overflown |= r.1;
}
exp /= 2;
r = base.overflowing_mul(base);
base = r.0;
overflown |= r.1;
}
// since exp!=0, finally the exp must be 1.
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
r = acc.overflowing_mul(base);
r.1 |= overflown;
r
}
/// Raises self to the power of `exp`, using exponentiation by squaring.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")]
/// ```
#[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;
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
}
/// 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 0.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")]
/// ```
#[stable(feature = "euclidean_division", since = "1.38.0")]
#[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[rustc_inherit_overflow_checks]
pub const fn div_euclid(self, rhs: Self) -> Self {
self / rhs
}
/// Calculates the least remainder of `self (mod rhs)`.
///
/// Since, for the positive integers, all common
/// definitions of division are equal, this
/// is exactly equal to `self % rhs`.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // 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)]
#[rustc_inherit_overflow_checks]
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 0.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// #![feature(int_roundings)]
#[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")]
/// ```
#[unstable(feature = "int_roundings", issue = "88581")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline(always)]
#[rustc_inherit_overflow_checks]
pub const fn div_floor(self, rhs: Self) -> Self {
self / rhs
}
/// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// #![feature(int_roundings)]
#[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")]
/// ```
#[unstable(feature = "int_roundings", issue = "88581")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn div_ceil(self, rhs: Self) -> Self {
let d = self / rhs;
let r = self % rhs;
if r > 0 && rhs > 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 0 or the operation results in overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// #![feature(int_roundings)]
#[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
#[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
/// ```
#[unstable(feature = "int_roundings", issue = "88581")]
#[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` is `rhs` is zero or the
/// operation would result in overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// #![feature(int_roundings)]
#[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);")]
/// ```
#[unstable(feature = "int_roundings", issue = "88581")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
match try_opt!(self.checked_rem(rhs)) {
0 => Some(self),
r => self.checked_add(try_opt!(rhs.checked_sub(r)))
}
}
/// Returns `true` if and only if `self == 2^k` for some `k`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[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]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
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) };
<$SelfT>::MAX >> z
}
/// Returns the smallest power of two greater than or equal to `self`.
///
/// When return value overflows (i.e., `self > (1 << (N-1))` for type
/// `uN`), it panics in debug mode and the return value is wrapped to 0 in
/// release mode (the only situation in which method can return 0).
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")]
#[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")]
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub const fn next_power_of_two(self) -> Self {
self.one_less_than_next_power_of_two() + 1
}
/// Returns the smallest power of two greater than or equal to `n`. If
/// the next power of two is greater than the type's maximum value,
/// `None` is returned, otherwise the power of two is wrapped in `Some`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("assert_eq!(2", stringify!($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
///
/// Basic usage:
///
/// ```
/// #![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);")]
/// ```
#[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
reason = "needs decision on wrapping behaviour")]
#[rustc_const_unstable(feature = "wrapping_next_power_of_two", issue = "32463")]
#[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)
}
/// Return 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; mem::size_of::<Self>()] {
self.to_be().to_ne_bytes()
}
/// Return 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; mem::size_of::<Self>()] {
self.to_le().to_ne_bytes()
}
/// Return the memory representation of this integer as a byte array in
/// native byte order.
///
/// As the target platform's native endianness is used, portable code
/// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
/// instead.
///
#[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"]
// 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; mem::size_of::<Self>()] {
// SAFETY: integers are plain old datatypes so we can always transmute them to
// arrays of bytes
unsafe { mem::transmute(self) }
}
/// Create 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!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($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; mem::size_of::<Self>()]) -> Self {
Self::from_be(Self::from_ne_bytes(bytes))
}
/// Create 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!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($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; mem::size_of::<Self>()]) -> Self {
Self::from_le(Self::from_ne_bytes(bytes))
}
/// Create 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!($SelfT), " {")]
#[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
/// *input = rest;
#[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
/// }
/// ```
#[stable(feature = "int_to_from_bytes", since = "1.32.0")]
#[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
#[must_use]
// SAFETY: const sound because integers are plain old datatypes so we can always
// transmute to them
#[inline]
pub const fn from_ne_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
// SAFETY: integers are plain old datatypes so we can always transmute to them
unsafe { mem::transmute(bytes) }
}
/// New code should prefer to use
#[doc = concat!("[`", stringify!($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")]
#[rustc_deprecated(since = "TBD", reason = "replaced by the `MIN` associated constant on this type")]
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")]
#[rustc_deprecated(since = "TBD", reason = "replaced by the `MAX` associated constant on this type")]
pub const fn max_value() -> Self { Self::MAX }
}
}