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//! Definitions of integer that is known not to equal zero.
use crate::fmt;
use crate::ops::{BitOr, BitOrAssign, Div, Rem};
use crate::str::FromStr;
use super::from_str_radix;
use super::{IntErrorKind, ParseIntError};
use crate::intrinsics;
macro_rules! impl_nonzero_fmt {
( #[$stability: meta] ( $( $Trait: ident ),+ ) for $Ty: ident ) => {
$(
#[$stability]
impl fmt::$Trait for $Ty {
#[inline]
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
self.get().fmt(f)
}
}
)+
}
}
macro_rules! nonzero_integers {
( $( #[$stability: meta] #[$const_new_unchecked_stability: meta] $Ty: ident($Int: ty); )+ ) => {
$(
/// An integer that is known not to equal zero.
///
/// This enables some memory layout optimization.
#[doc = concat!("For example, `Option<", stringify!($Ty), ">` is the same size as `", stringify!($Int), "`:")]
///
/// ```rust
/// use std::mem::size_of;
#[doc = concat!("assert_eq!(size_of::<Option<core::num::", stringify!($Ty), ">>(), size_of::<", stringify!($Int), ">());")]
/// ```
#[$stability]
#[derive(Copy, Clone, Eq, PartialEq, Ord, PartialOrd, Hash)]
#[repr(transparent)]
#[rustc_layout_scalar_valid_range_start(1)]
#[rustc_nonnull_optimization_guaranteed]
pub struct $Ty($Int);
impl $Ty {
/// Creates a non-zero without checking whether the value is non-zero.
/// This results in undefined behaviour if the value is zero.
///
/// # Safety
///
/// The value must not be zero.
#[$stability]
#[$const_new_unchecked_stability]
#[must_use]
#[inline]
pub const unsafe fn new_unchecked(n: $Int) -> Self {
// SAFETY: this is guaranteed to be safe by the caller.
unsafe {
core::intrinsics::assert_unsafe_precondition!(n != 0);
Self(n)
}
}
/// Creates a non-zero if the given value is not zero.
#[$stability]
#[rustc_const_stable(feature = "const_nonzero_int_methods", since = "1.47.0")]
#[must_use]
#[inline]
pub const fn new(n: $Int) -> Option<Self> {
if n != 0 {
// SAFETY: we just checked that there's no `0`
Some(unsafe { Self(n) })
} else {
None
}
}
/// Returns the value as a primitive type.
#[$stability]
#[inline]
#[rustc_const_stable(feature = "const_nonzero_get", since = "1.34.0")]
pub const fn get(self) -> $Int {
self.0
}
}
#[stable(feature = "from_nonzero", since = "1.31.0")]
#[rustc_const_unstable(feature = "const_num_from_num", issue = "87852")]
impl const From<$Ty> for $Int {
#[doc = concat!("Converts a `", stringify!($Ty), "` into an `", stringify!($Int), "`")]
#[inline]
fn from(nonzero: $Ty) -> Self {
nonzero.0
}
}
#[stable(feature = "nonzero_bitor", since = "1.45.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "90080")]
impl const BitOr for $Ty {
type Output = Self;
#[inline]
fn bitor(self, rhs: Self) -> Self::Output {
// SAFETY: since `self` and `rhs` are both nonzero, the
// result of the bitwise-or will be nonzero.
unsafe { $Ty::new_unchecked(self.get() | rhs.get()) }
}
}
#[stable(feature = "nonzero_bitor", since = "1.45.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "90080")]
impl const BitOr<$Int> for $Ty {
type Output = Self;
#[inline]
fn bitor(self, rhs: $Int) -> Self::Output {
// SAFETY: since `self` is nonzero, the result of the
// bitwise-or will be nonzero regardless of the value of
// `rhs`.
unsafe { $Ty::new_unchecked(self.get() | rhs) }
}
}
#[stable(feature = "nonzero_bitor", since = "1.45.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "90080")]
impl const BitOr<$Ty> for $Int {
type Output = $Ty;
#[inline]
fn bitor(self, rhs: $Ty) -> Self::Output {
// SAFETY: since `rhs` is nonzero, the result of the
// bitwise-or will be nonzero regardless of the value of
// `self`.
unsafe { $Ty::new_unchecked(self | rhs.get()) }
}
}
#[stable(feature = "nonzero_bitor", since = "1.45.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "90080")]
impl const BitOrAssign for $Ty {
#[inline]
fn bitor_assign(&mut self, rhs: Self) {
*self = *self | rhs;
}
}
#[stable(feature = "nonzero_bitor", since = "1.45.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "90080")]
impl const BitOrAssign<$Int> for $Ty {
#[inline]
fn bitor_assign(&mut self, rhs: $Int) {
*self = *self | rhs;
}
}
impl_nonzero_fmt! {
#[$stability] (Debug, Display, Binary, Octal, LowerHex, UpperHex) for $Ty
}
)+
}
}
nonzero_integers! {
#[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU8(u8);
#[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU16(u16);
#[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU32(u32);
#[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU64(u64);
#[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroU128(u128);
#[stable(feature = "nonzero", since = "1.28.0")] #[rustc_const_stable(feature = "nonzero", since = "1.28.0")] NonZeroUsize(usize);
#[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI8(i8);
#[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI16(i16);
#[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI32(i32);
#[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI64(i64);
#[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroI128(i128);
#[stable(feature = "signed_nonzero", since = "1.34.0")] #[rustc_const_stable(feature = "signed_nonzero", since = "1.34.0")] NonZeroIsize(isize);
}
macro_rules! from_str_radix_nzint_impl {
($($t:ty)*) => {$(
#[stable(feature = "nonzero_parse", since = "1.35.0")]
impl FromStr for $t {
type Err = ParseIntError;
fn from_str(src: &str) -> Result<Self, Self::Err> {
Self::new(from_str_radix(src, 10)?)
.ok_or(ParseIntError {
kind: IntErrorKind::Zero
})
}
}
)*}
}
from_str_radix_nzint_impl! { NonZeroU8 NonZeroU16 NonZeroU32 NonZeroU64 NonZeroU128 NonZeroUsize
NonZeroI8 NonZeroI16 NonZeroI32 NonZeroI64 NonZeroI128 NonZeroIsize }
macro_rules! nonzero_leading_trailing_zeros {
( $( $Ty: ident($Uint: ty) , $LeadingTestExpr:expr ;)+ ) => {
$(
impl $Ty {
/// Returns the number of leading zeros in the binary representation of `self`.
///
/// On many architectures, this function can perform better than `leading_zeros()` on the underlying integer type, as special handling of zero can be avoided.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = std::num::", stringify!($Ty), "::new(", stringify!($LeadingTestExpr), ").unwrap();")]
///
/// assert_eq!(n.leading_zeros(), 0);
/// ```
#[stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
#[rustc_const_stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn leading_zeros(self) -> u32 {
// SAFETY: since `self` can not be zero it is safe to call ctlz_nonzero
unsafe { intrinsics::ctlz_nonzero(self.0 as $Uint) as u32 }
}
/// Returns the number of trailing zeros in the binary representation
/// of `self`.
///
/// On many architectures, this function can perform better than `trailing_zeros()` on the underlying integer type, as special handling of zero can be avoided.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let n = std::num::", stringify!($Ty), "::new(0b0101000).unwrap();")]
///
/// assert_eq!(n.trailing_zeros(), 3);
/// ```
#[stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
#[rustc_const_stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn trailing_zeros(self) -> u32 {
// SAFETY: since `self` can not be zero it is safe to call cttz_nonzero
unsafe { intrinsics::cttz_nonzero(self.0 as $Uint) as u32 }
}
}
)+
}
}
nonzero_leading_trailing_zeros! {
NonZeroU8(u8), u8::MAX;
NonZeroU16(u16), u16::MAX;
NonZeroU32(u32), u32::MAX;
NonZeroU64(u64), u64::MAX;
NonZeroU128(u128), u128::MAX;
NonZeroUsize(usize), usize::MAX;
NonZeroI8(u8), -1i8;
NonZeroI16(u16), -1i16;
NonZeroI32(u32), -1i32;
NonZeroI64(u64), -1i64;
NonZeroI128(u128), -1i128;
NonZeroIsize(usize), -1isize;
}
macro_rules! nonzero_integers_div {
( $( $Ty: ident($Int: ty); )+ ) => {
$(
#[stable(feature = "nonzero_div", since = "1.51.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "90080")]
impl const Div<$Ty> for $Int {
type Output = $Int;
/// This operation rounds towards zero,
/// truncating any fractional part of the exact result, and cannot panic.
#[inline]
fn div(self, other: $Ty) -> $Int {
// SAFETY: div by zero is checked because `other` is a nonzero,
// and MIN/-1 is checked because `self` is an unsigned int.
unsafe { crate::intrinsics::unchecked_div(self, other.get()) }
}
}
#[stable(feature = "nonzero_div", since = "1.51.0")]
#[rustc_const_unstable(feature = "const_ops", issue = "90080")]
impl const Rem<$Ty> for $Int {
type Output = $Int;
/// This operation satisfies `n % d == n - (n / d) * d`, and cannot panic.
#[inline]
fn rem(self, other: $Ty) -> $Int {
// SAFETY: rem by zero is checked because `other` is a nonzero,
// and MIN/-1 is checked because `self` is an unsigned int.
unsafe { crate::intrinsics::unchecked_rem(self, other.get()) }
}
}
)+
}
}
nonzero_integers_div! {
NonZeroU8(u8);
NonZeroU16(u16);
NonZeroU32(u32);
NonZeroU64(u64);
NonZeroU128(u128);
NonZeroUsize(usize);
}
// A bunch of methods for unsigned nonzero types only.
macro_rules! nonzero_unsigned_operations {
( $( $Ty: ident($Int: ident); )+ ) => {
$(
impl $Ty {
/// Add an unsigned integer to a non-zero value.
/// Check for overflow and return [`None`] on overflow
/// As a consequence, the result cannot wrap to zero.
///
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let one = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let two = ", stringify!($Ty), "::new(2)?;")]
#[doc = concat!("let max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX)?;")]
///
/// assert_eq!(Some(two), one.checked_add(1));
/// assert_eq!(None, max.checked_add(1));
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_add(self, other: $Int) -> Option<$Ty> {
if let Some(result) = self.get().checked_add(other) {
// SAFETY: $Int::checked_add returns None on overflow
// so the result cannot be zero.
Some(unsafe { $Ty::new_unchecked(result) })
} else {
None
}
}
/// Add an unsigned integer to a non-zero value.
#[doc = concat!("Return [`", stringify!($Int), "::MAX`] on overflow.")]
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let one = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let two = ", stringify!($Ty), "::new(2)?;")]
#[doc = concat!("let max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX)?;")]
///
/// assert_eq!(two, one.saturating_add(1));
/// assert_eq!(max, max.saturating_add(1));
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_add(self, other: $Int) -> $Ty {
// SAFETY: $Int::saturating_add returns $Int::MAX on overflow
// so the result cannot be zero.
unsafe { $Ty::new_unchecked(self.get().saturating_add(other)) }
}
/// Add an unsigned integer to a non-zero value,
/// assuming overflow cannot occur.
/// Overflow is unchecked, and it is undefined behaviour to overflow
/// *even if the result would wrap to a non-zero value*.
/// The behaviour is undefined as soon as
#[doc = concat!("`self + rhs > ", stringify!($Int), "::MAX`.")]
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let one = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let two = ", stringify!($Ty), "::new(2)?;")]
///
/// assert_eq!(two, unsafe { one.unchecked_add(1) });
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const unsafe fn unchecked_add(self, other: $Int) -> $Ty {
// SAFETY: The caller ensures there is no overflow.
unsafe { $Ty::new_unchecked(self.get().unchecked_add(other)) }
}
/// Returns the smallest power of two greater than or equal to n.
/// Check for overflow and return [`None`]
/// if the next power of two is greater than the type’s maximum value.
/// As a consequence, the result cannot wrap to zero.
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let two = ", stringify!($Ty), "::new(2)?;")]
#[doc = concat!("let three = ", stringify!($Ty), "::new(3)?;")]
#[doc = concat!("let four = ", stringify!($Ty), "::new(4)?;")]
#[doc = concat!("let max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX)?;")]
///
/// assert_eq!(Some(two), two.checked_next_power_of_two() );
/// assert_eq!(Some(four), three.checked_next_power_of_two() );
/// assert_eq!(None, max.checked_next_power_of_two() );
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_next_power_of_two(self) -> Option<$Ty> {
if let Some(nz) = self.get().checked_next_power_of_two() {
// SAFETY: The next power of two is positive
// and overflow is checked.
Some(unsafe { $Ty::new_unchecked(nz) })
} else {
None
}
}
/// Returns the base 2 logarithm of the number, rounded down.
///
/// This is the same operation as
#[doc = concat!("[`", stringify!($Int), "::log2`],")]
/// except that it has no failure cases to worry about
/// since this value can never be zero.
///
/// # Examples
///
/// ```
/// #![feature(int_log)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
#[doc = concat!("assert_eq!(", stringify!($Ty), "::new(7).unwrap().log2(), 2);")]
#[doc = concat!("assert_eq!(", stringify!($Ty), "::new(8).unwrap().log2(), 3);")]
#[doc = concat!("assert_eq!(", stringify!($Ty), "::new(9).unwrap().log2(), 3);")]
/// ```
#[unstable(feature = "int_log", issue = "70887")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn log2(self) -> u32 {
Self::BITS - 1 - self.leading_zeros()
}
/// Returns the base 10 logarithm of the number, rounded down.
///
/// This is the same operation as
#[doc = concat!("[`", stringify!($Int), "::log10`],")]
/// except that it has no failure cases to worry about
/// since this value can never be zero.
///
/// # Examples
///
/// ```
/// #![feature(int_log)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
#[doc = concat!("assert_eq!(", stringify!($Ty), "::new(99).unwrap().log10(), 1);")]
#[doc = concat!("assert_eq!(", stringify!($Ty), "::new(100).unwrap().log10(), 2);")]
#[doc = concat!("assert_eq!(", stringify!($Ty), "::new(101).unwrap().log10(), 2);")]
/// ```
#[unstable(feature = "int_log", issue = "70887")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn log10(self) -> u32 {
super::int_log10::$Int(self.0)
}
}
)+
}
}
nonzero_unsigned_operations! {
NonZeroU8(u8);
NonZeroU16(u16);
NonZeroU32(u32);
NonZeroU64(u64);
NonZeroU128(u128);
NonZeroUsize(usize);
}
// A bunch of methods for signed nonzero types only.
macro_rules! nonzero_signed_operations {
( $( $Ty: ident($Int: ty) -> $Uty: ident($Uint: ty); )+ ) => {
$(
impl $Ty {
/// Computes the absolute value of self.
#[doc = concat!("See [`", stringify!($Int), "::abs`]")]
/// for documentation on overflow behaviour.
///
/// # Example
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let pos = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let neg = ", stringify!($Ty), "::new(-1)?;")]
///
/// assert_eq!(pos, pos.abs());
/// assert_eq!(pos, neg.abs());
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn abs(self) -> $Ty {
// SAFETY: This cannot overflow to zero.
unsafe { $Ty::new_unchecked(self.get().abs()) }
}
/// Checked absolute value.
/// Check for overflow and returns [`None`] if
#[doc = concat!("`self == ", stringify!($Int), "::MIN`.")]
/// The result cannot be zero.
///
/// # Example
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let pos = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let neg = ", stringify!($Ty), "::new(-1)?;")]
#[doc = concat!("let min = ", stringify!($Ty), "::new(",
stringify!($Int), "::MIN)?;")]
///
/// assert_eq!(Some(pos), neg.checked_abs());
/// assert_eq!(None, min.checked_abs());
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_abs(self) -> Option<$Ty> {
if let Some(nz) = self.get().checked_abs() {
// SAFETY: absolute value of nonzero cannot yield zero values.
Some(unsafe { $Ty::new_unchecked(nz) })
} else {
None
}
}
/// Computes the absolute value of self,
/// with overflow information, see
#[doc = concat!("[`", stringify!($Int), "::overflowing_abs`].")]
///
/// # Example
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let pos = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let neg = ", stringify!($Ty), "::new(-1)?;")]
#[doc = concat!("let min = ", stringify!($Ty), "::new(",
stringify!($Int), "::MIN)?;")]
///
/// assert_eq!((pos, false), pos.overflowing_abs());
/// assert_eq!((pos, false), neg.overflowing_abs());
/// assert_eq!((min, true), min.overflowing_abs());
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn overflowing_abs(self) -> ($Ty, bool) {
let (nz, flag) = self.get().overflowing_abs();
(
// SAFETY: absolute value of nonzero cannot yield zero values.
unsafe { $Ty::new_unchecked(nz) },
flag,
)
}
/// Saturating absolute value, see
#[doc = concat!("[`", stringify!($Int), "::saturating_abs`].")]
///
/// # Example
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let pos = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let neg = ", stringify!($Ty), "::new(-1)?;")]
#[doc = concat!("let min = ", stringify!($Ty), "::new(",
stringify!($Int), "::MIN)?;")]
#[doc = concat!("let min_plus = ", stringify!($Ty), "::new(",
stringify!($Int), "::MIN + 1)?;")]
#[doc = concat!("let max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX)?;")]
///
/// assert_eq!(pos, pos.saturating_abs());
/// assert_eq!(pos, neg.saturating_abs());
/// assert_eq!(max, min.saturating_abs());
/// assert_eq!(max, min_plus.saturating_abs());
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_abs(self) -> $Ty {
// SAFETY: absolute value of nonzero cannot yield zero values.
unsafe { $Ty::new_unchecked(self.get().saturating_abs()) }
}
/// Wrapping absolute value, see
#[doc = concat!("[`", stringify!($Int), "::wrapping_abs`].")]
///
/// # Example
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let pos = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let neg = ", stringify!($Ty), "::new(-1)?;")]
#[doc = concat!("let min = ", stringify!($Ty), "::new(",
stringify!($Int), "::MIN)?;")]
#[doc = concat!("let max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX)?;")]
///
/// assert_eq!(pos, pos.wrapping_abs());
/// assert_eq!(pos, neg.wrapping_abs());
/// assert_eq!(min, min.wrapping_abs());
/// # // FIXME: add once Neg is implemented?
/// # // assert_eq!(max, (-max).wrapping_abs());
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn wrapping_abs(self) -> $Ty {
// SAFETY: absolute value of nonzero cannot yield zero values.
unsafe { $Ty::new_unchecked(self.get().wrapping_abs()) }
}
/// Computes the absolute value of self
/// without any wrapping or panicking.
///
/// # Example
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
#[doc = concat!("# use std::num::", stringify!($Uty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let u_pos = ", stringify!($Uty), "::new(1)?;")]
#[doc = concat!("let i_pos = ", stringify!($Ty), "::new(1)?;")]
#[doc = concat!("let i_neg = ", stringify!($Ty), "::new(-1)?;")]
#[doc = concat!("let i_min = ", stringify!($Ty), "::new(",
stringify!($Int), "::MIN)?;")]
#[doc = concat!("let u_max = ", stringify!($Uty), "::new(",
stringify!($Uint), "::MAX / 2 + 1)?;")]
///
/// assert_eq!(u_pos, i_pos.unsigned_abs());
/// assert_eq!(u_pos, i_neg.unsigned_abs());
/// assert_eq!(u_max, i_min.unsigned_abs());
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn unsigned_abs(self) -> $Uty {
// SAFETY: absolute value of nonzero cannot yield zero values.
unsafe { $Uty::new_unchecked(self.get().unsigned_abs()) }
}
}
)+
}
}
nonzero_signed_operations! {
NonZeroI8(i8) -> NonZeroU8(u8);
NonZeroI16(i16) -> NonZeroU16(u16);
NonZeroI32(i32) -> NonZeroU32(u32);
NonZeroI64(i64) -> NonZeroU64(u64);
NonZeroI128(i128) -> NonZeroU128(u128);
NonZeroIsize(isize) -> NonZeroUsize(usize);
}
// A bunch of methods for both signed and unsigned nonzero types.
macro_rules! nonzero_unsigned_signed_operations {
( $( $signedness:ident $Ty: ident($Int: ty); )+ ) => {
$(
impl $Ty {
/// Multiply two non-zero integers together.
/// Check for overflow and return [`None`] on overflow.
/// As a consequence, the result cannot wrap to zero.
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let two = ", stringify!($Ty), "::new(2)?;")]
#[doc = concat!("let four = ", stringify!($Ty), "::new(4)?;")]
#[doc = concat!("let max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX)?;")]
///
/// assert_eq!(Some(four), two.checked_mul(two));
/// assert_eq!(None, max.checked_mul(two));
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_mul(self, other: $Ty) -> Option<$Ty> {
if let Some(result) = self.get().checked_mul(other.get()) {
// SAFETY: checked_mul returns None on overflow
// and `other` is also non-null
// so the result cannot be zero.
Some(unsafe { $Ty::new_unchecked(result) })
} else {
None
}
}
/// Multiply two non-zero integers together.
#[doc = concat!("Return [`", stringify!($Int), "::MAX`] on overflow.")]
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let two = ", stringify!($Ty), "::new(2)?;")]
#[doc = concat!("let four = ", stringify!($Ty), "::new(4)?;")]
#[doc = concat!("let max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX)?;")]
///
/// assert_eq!(four, two.saturating_mul(two));
/// assert_eq!(max, four.saturating_mul(max));
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_mul(self, other: $Ty) -> $Ty {
// SAFETY: saturating_mul returns u*::MAX on overflow
// and `other` is also non-null
// so the result cannot be zero.
unsafe { $Ty::new_unchecked(self.get().saturating_mul(other.get())) }
}
/// Multiply two non-zero integers together,
/// assuming overflow cannot occur.
/// Overflow is unchecked, and it is undefined behaviour to overflow
/// *even if the result would wrap to a non-zero value*.
/// The behaviour is undefined as soon as
#[doc = sign_dependent_expr!{
$signedness ?
if signed {
concat!("`self * rhs > ", stringify!($Int), "::MAX`, ",
"or `self * rhs < ", stringify!($Int), "::MIN`.")
}
if unsigned {
concat!("`self * rhs > ", stringify!($Int), "::MAX`.")
}
}]
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let two = ", stringify!($Ty), "::new(2)?;")]
#[doc = concat!("let four = ", stringify!($Ty), "::new(4)?;")]
///
/// assert_eq!(four, unsafe { two.unchecked_mul(two) });
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const unsafe fn unchecked_mul(self, other: $Ty) -> $Ty {
// SAFETY: The caller ensures there is no overflow.
unsafe { $Ty::new_unchecked(self.get().unchecked_mul(other.get())) }
}
/// Raise non-zero value to an integer power.
/// Check for overflow and return [`None`] on overflow.
/// As a consequence, the result cannot wrap to zero.
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let three = ", stringify!($Ty), "::new(3)?;")]
#[doc = concat!("let twenty_seven = ", stringify!($Ty), "::new(27)?;")]
#[doc = concat!("let half_max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX / 2)?;")]
///
/// assert_eq!(Some(twenty_seven), three.checked_pow(3));
/// assert_eq!(None, half_max.checked_pow(3));
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn checked_pow(self, other: u32) -> Option<$Ty> {
if let Some(result) = self.get().checked_pow(other) {
// SAFETY: checked_pow returns None on overflow
// so the result cannot be zero.
Some(unsafe { $Ty::new_unchecked(result) })
} else {
None
}
}
/// Raise non-zero value to an integer power.
#[doc = sign_dependent_expr!{
$signedness ?
if signed {
concat!("Return [`", stringify!($Int), "::MIN`] ",
"or [`", stringify!($Int), "::MAX`] on overflow.")
}
if unsigned {
concat!("Return [`", stringify!($Int), "::MAX`] on overflow.")
}
}]
///
/// # Examples
///
/// ```
/// #![feature(nonzero_ops)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
/// # fn main() { test().unwrap(); }
/// # fn test() -> Option<()> {
#[doc = concat!("let three = ", stringify!($Ty), "::new(3)?;")]
#[doc = concat!("let twenty_seven = ", stringify!($Ty), "::new(27)?;")]
#[doc = concat!("let max = ", stringify!($Ty), "::new(",
stringify!($Int), "::MAX)?;")]
///
/// assert_eq!(twenty_seven, three.saturating_pow(3));
/// assert_eq!(max, max.saturating_pow(3));
/// # Some(())
/// # }
/// ```
#[unstable(feature = "nonzero_ops", issue = "84186")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub const fn saturating_pow(self, other: u32) -> $Ty {
// SAFETY: saturating_pow returns u*::MAX on overflow
// so the result cannot be zero.
unsafe { $Ty::new_unchecked(self.get().saturating_pow(other)) }
}
}
)+
}
}
// Use this when the generated code should differ between signed and unsigned types.
macro_rules! sign_dependent_expr {
(signed ? if signed { $signed_case:expr } if unsigned { $unsigned_case:expr } ) => {
$signed_case
};
(unsigned ? if signed { $signed_case:expr } if unsigned { $unsigned_case:expr } ) => {
$unsigned_case
};
}
nonzero_unsigned_signed_operations! {
unsigned NonZeroU8(u8);
unsigned NonZeroU16(u16);
unsigned NonZeroU32(u32);
unsigned NonZeroU64(u64);
unsigned NonZeroU128(u128);
unsigned NonZeroUsize(usize);
signed NonZeroI8(i8);
signed NonZeroI16(i16);
signed NonZeroI32(i32);
signed NonZeroI64(i64);
signed NonZeroI128(i128);
signed NonZeroIsize(isize);
}
macro_rules! nonzero_unsigned_is_power_of_two {
( $( $Ty: ident )+ ) => {
$(
impl $Ty {
/// Returns `true` if and only if `self == (1 << k)` for some `k`.
///
/// On many architectures, this function can perform better than `is_power_of_two()`
/// on the underlying integer type, as special handling of zero can be avoided.
///
/// # Examples
///
/// Basic usage:
///
/// ```
#[doc = concat!("let eight = std::num::", stringify!($Ty), "::new(8).unwrap();")]
/// assert!(eight.is_power_of_two());
#[doc = concat!("let ten = std::num::", stringify!($Ty), "::new(10).unwrap();")]
/// assert!(!ten.is_power_of_two());
/// ```
#[must_use]
#[stable(feature = "nonzero_is_power_of_two", since = "1.59.0")]
#[rustc_const_stable(feature = "nonzero_is_power_of_two", since = "1.59.0")]
#[inline]
pub const fn is_power_of_two(self) -> bool {
// LLVM 11 normalizes `unchecked_sub(x, 1) & x == 0` to the implementation seen here.
// On the basic x86-64 target, this saves 3 instructions for the zero check.
// On x86_64 with BMI1, being nonzero lets it codegen to `BLSR`, which saves an instruction
// compared to the `POPCNT` implementation on the underlying integer type.
intrinsics::ctpop(self.get()) < 2
}
}
)+
}
}
nonzero_unsigned_is_power_of_two! { NonZeroU8 NonZeroU16 NonZeroU32 NonZeroU64 NonZeroU128 NonZeroUsize }
macro_rules! nonzero_min_max_unsigned {
( $( $Ty: ident($Int: ident); )+ ) => {
$(
impl $Ty {
/// The smallest value that can be represented by this non-zero
/// integer type, 1.
///
/// # Examples
///
/// ```
/// #![feature(nonzero_min_max)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
#[doc = concat!("assert_eq!(", stringify!($Ty), "::MIN.get(), 1", stringify!($Int), ");")]
/// ```
#[unstable(feature = "nonzero_min_max", issue = "89065")]
pub const MIN: Self = Self::new(1).unwrap();
/// The largest value that can be represented by this non-zero
/// integer type,
#[doc = concat!("equal to [`", stringify!($Int), "::MAX`].")]
///
/// # Examples
///
/// ```
/// #![feature(nonzero_min_max)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
#[doc = concat!("assert_eq!(", stringify!($Ty), "::MAX.get(), ", stringify!($Int), "::MAX);")]
/// ```
#[unstable(feature = "nonzero_min_max", issue = "89065")]
pub const MAX: Self = Self::new(<$Int>::MAX).unwrap();
}
)+
}
}
macro_rules! nonzero_min_max_signed {
( $( $Ty: ident($Int: ident); )+ ) => {
$(
impl $Ty {
/// The smallest value that can be represented by this non-zero
/// integer type,
#[doc = concat!("equal to [`", stringify!($Int), "::MIN`].")]
///
/// Note: While most integer types are defined for every whole
/// number between `MIN` and `MAX`, signed non-zero integers are
/// a special case. They have a "gap" at 0.
///
/// # Examples
///
/// ```
/// #![feature(nonzero_min_max)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
#[doc = concat!("assert_eq!(", stringify!($Ty), "::MIN.get(), ", stringify!($Int), "::MIN);")]
/// ```
#[unstable(feature = "nonzero_min_max", issue = "89065")]
pub const MIN: Self = Self::new(<$Int>::MIN).unwrap();
/// The largest value that can be represented by this non-zero
/// integer type,
#[doc = concat!("equal to [`", stringify!($Int), "::MAX`].")]
///
/// Note: While most integer types are defined for every whole
/// number between `MIN` and `MAX`, signed non-zero integers are
/// a special case. They have a "gap" at 0.
///
/// # Examples
///
/// ```
/// #![feature(nonzero_min_max)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
#[doc = concat!("assert_eq!(", stringify!($Ty), "::MAX.get(), ", stringify!($Int), "::MAX);")]
/// ```
#[unstable(feature = "nonzero_min_max", issue = "89065")]
pub const MAX: Self = Self::new(<$Int>::MAX).unwrap();
}
)+
}
}
nonzero_min_max_unsigned! {
NonZeroU8(u8);
NonZeroU16(u16);
NonZeroU32(u32);
NonZeroU64(u64);
NonZeroU128(u128);
NonZeroUsize(usize);
}
nonzero_min_max_signed! {
NonZeroI8(i8);
NonZeroI16(i16);
NonZeroI32(i32);
NonZeroI64(i64);
NonZeroI128(i128);
NonZeroIsize(isize);
}
macro_rules! nonzero_bits {
( $( $Ty: ident($Int: ty); )+ ) => {
$(
impl $Ty {
/// The size of this non-zero integer type in bits.
///
#[doc = concat!("This value is equal to [`", stringify!($Int), "::BITS`].")]
///
/// # Examples
///
/// ```
/// #![feature(nonzero_bits)]
#[doc = concat!("# use std::num::", stringify!($Ty), ";")]
///
#[doc = concat!("assert_eq!(", stringify!($Ty), "::BITS, ", stringify!($Int), "::BITS);")]
/// ```
#[unstable(feature = "nonzero_bits", issue = "94881")]
pub const BITS: u32 = <$Int>::BITS;
}
)+
}
}
nonzero_bits! {
NonZeroU8(u8);
NonZeroI8(i8);
NonZeroU16(u16);
NonZeroI16(i16);
NonZeroU32(u32);
NonZeroI32(i32);
NonZeroU64(u64);
NonZeroI64(i64);
NonZeroU128(u128);
NonZeroI128(i128);
NonZeroUsize(usize);
NonZeroIsize(isize);
}