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core/num/
nonzero.rs

1//! Definitions of integer that is known not to equal zero.
2
3use super::{IntErrorKind, ParseIntError};
4use crate::clone::{TrivialClone, UseCloned};
5use crate::cmp::Ordering;
6use crate::hash::{Hash, Hasher};
7use crate::marker::{Destruct, Freeze, StructuralPartialEq};
8use crate::num::imp;
9use crate::ops::{BitOr, BitOrAssign, Div, DivAssign, Neg, Rem, RemAssign};
10use crate::panic::{RefUnwindSafe, UnwindSafe};
11use crate::str::FromStr;
12use crate::{fmt, intrinsics, ptr, ub_checks};
13
14/// A marker trait for primitive types which can be zero.
15///
16/// This is an implementation detail for <code>[NonZero]\<T></code> which may disappear or be replaced at any time.
17///
18/// # Safety
19///
20/// Types implementing this trait must be primitives that are valid when zeroed.
21///
22/// The associated `Self::NonZeroInner` type must have the same size+align as `Self`,
23/// but with a niche and bit validity making it so the following `transmutes` are sound:
24///
25/// - `Self::NonZeroInner` to `Option<Self::NonZeroInner>`
26/// - `Option<Self::NonZeroInner>` to `Self`
27///
28/// (And, consequently, `Self::NonZeroInner` to `Self`.)
29#[unstable(
30    feature = "nonzero_internals",
31    reason = "implementation detail which may disappear or be replaced at any time",
32    issue = "none"
33)]
34pub impl(self) unsafe trait ZeroablePrimitive: Sized + Copy {
35    /// A type like `Self` but with a niche that includes zero.
36    type NonZeroInner: Sized + Copy;
37}
38
39macro_rules! impl_zeroable_primitive {
40    ($($NonZeroInner:ident ( $primitive:ty )),+ $(,)?) => {
41        $(
42            #[unstable(
43                feature = "nonzero_internals",
44                reason = "implementation detail which may disappear or be replaced at any time",
45                issue = "none"
46            )]
47            unsafe impl ZeroablePrimitive for $primitive {
48                type NonZeroInner = super::niche_types::$NonZeroInner;
49            }
50        )+
51    };
52}
53
54impl_zeroable_primitive!(
55    NonZeroU8Inner(u8),
56    NonZeroU16Inner(u16),
57    NonZeroU32Inner(u32),
58    NonZeroU64Inner(u64),
59    NonZeroU128Inner(u128),
60    NonZeroUsizeInner(usize),
61    NonZeroI8Inner(i8),
62    NonZeroI16Inner(i16),
63    NonZeroI32Inner(i32),
64    NonZeroI64Inner(i64),
65    NonZeroI128Inner(i128),
66    NonZeroIsizeInner(isize),
67    NonZeroCharInner(char),
68);
69
70/// A value that is known not to equal zero.
71///
72/// This enables some memory layout optimization.
73/// For example, `Option<NonZero<u32>>` is the same size as `u32`:
74///
75/// ```
76/// use core::num::NonZero;
77///
78/// assert_eq!(size_of::<Option<NonZero<u32>>>(), size_of::<u32>());
79/// ```
80///
81/// # Layout
82///
83/// `NonZero<T>` is guaranteed to have the same layout and bit validity as `T`
84/// with the exception that the all-zero bit pattern is invalid.
85/// `Option<NonZero<T>>` is guaranteed to be ABI-compatible with `T`, including in
86/// FFI.
87///
88/// Thanks to the [null pointer optimization], `NonZero<T>` and
89/// `Option<NonZero<T>>` are guaranteed to have the same size and alignment:
90///
91/// ```
92/// use std::num::NonZero;
93///
94/// assert_eq!(size_of::<NonZero<u32>>(), size_of::<Option<NonZero<u32>>>());
95/// assert_eq!(align_of::<NonZero<u32>>(), align_of::<Option<NonZero<u32>>>());
96/// ```
97///
98/// [null pointer optimization]: crate::option#representation
99///
100/// # Note on generic usage
101///
102/// `NonZero<T>` can only be used with some standard library primitive types
103/// (such as `u8`, `i32`, and etc.). The type parameter `T` must implement the
104/// internal trait [`ZeroablePrimitive`], which is currently permanently unstable
105/// and cannot be implemented by users. Therefore, you cannot use `NonZero<T>`
106/// with your own types, nor can you implement traits for all `NonZero<T>`,
107/// only for concrete types.
108#[stable(feature = "generic_nonzero", since = "1.79.0")]
109#[repr(transparent)]
110#[rustc_nonnull_optimization_guaranteed]
111#[rustc_diagnostic_item = "NonZero"]
112pub struct NonZero<T: ZeroablePrimitive>(T::NonZeroInner);
113
114macro_rules! impl_nonzero_fmt {
115    ($(#[$Attribute:meta] $Trait:ident)*) => {
116        $(
117            #[$Attribute]
118            impl<T> fmt::$Trait for NonZero<T>
119            where
120                T: ZeroablePrimitive + fmt::$Trait,
121            {
122                #[inline]
123                fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
124                    self.get().fmt(f)
125                }
126            }
127        )*
128    };
129}
130
131impl_nonzero_fmt! {
132    #[stable(feature = "nonzero", since = "1.28.0")]
133    Debug
134    #[stable(feature = "nonzero", since = "1.28.0")]
135    Display
136    #[stable(feature = "nonzero", since = "1.28.0")]
137    Binary
138    #[stable(feature = "nonzero", since = "1.28.0")]
139    Octal
140    #[stable(feature = "nonzero", since = "1.28.0")]
141    LowerHex
142    #[stable(feature = "nonzero", since = "1.28.0")]
143    UpperHex
144    #[stable(feature = "nonzero_fmt_exp", since = "1.84.0")]
145    LowerExp
146    #[stable(feature = "nonzero_fmt_exp", since = "1.84.0")]
147    UpperExp
148}
149
150macro_rules! impl_nonzero_auto_trait {
151    (unsafe $Trait:ident) => {
152        #[stable(feature = "nonzero", since = "1.28.0")]
153        unsafe impl<T> $Trait for NonZero<T> where T: ZeroablePrimitive + $Trait {}
154    };
155    ($Trait:ident) => {
156        #[stable(feature = "nonzero", since = "1.28.0")]
157        impl<T> $Trait for NonZero<T> where T: ZeroablePrimitive + $Trait {}
158    };
159}
160
161// Implement auto-traits manually based on `T` to avoid docs exposing
162// the `ZeroablePrimitive::NonZeroInner` implementation detail.
163impl_nonzero_auto_trait!(unsafe Freeze);
164impl_nonzero_auto_trait!(RefUnwindSafe);
165impl_nonzero_auto_trait!(unsafe Send);
166impl_nonzero_auto_trait!(unsafe Sync);
167impl_nonzero_auto_trait!(Unpin);
168impl_nonzero_auto_trait!(UnwindSafe);
169
170#[stable(feature = "nonzero", since = "1.28.0")]
171#[rustc_const_unstable(feature = "const_clone", issue = "142757")]
172const impl<T> Clone for NonZero<T>
173where
174    T: ZeroablePrimitive,
175{
176    #[inline]
177    fn clone(&self) -> Self {
178        *self
179    }
180}
181
182#[unstable(feature = "ergonomic_clones", issue = "132290")]
183impl<T> UseCloned for NonZero<T> where T: ZeroablePrimitive {}
184
185#[stable(feature = "nonzero", since = "1.28.0")]
186impl<T> Copy for NonZero<T> where T: ZeroablePrimitive {}
187
188#[doc(hidden)]
189#[unstable(feature = "trivial_clone", issue = "none")]
190#[rustc_const_unstable(feature = "const_clone", issue = "142757")]
191const unsafe impl<T> TrivialClone for NonZero<T> where T: ZeroablePrimitive {}
192
193#[stable(feature = "nonzero", since = "1.28.0")]
194#[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
195const impl<T> PartialEq for NonZero<T>
196where
197    T: ZeroablePrimitive + [const] PartialEq,
198{
199    #[inline]
200    fn eq(&self, other: &Self) -> bool {
201        self.get() == other.get()
202    }
203
204    #[inline]
205    fn ne(&self, other: &Self) -> bool {
206        self.get() != other.get()
207    }
208}
209
210#[unstable(feature = "structural_match", issue = "31434")]
211impl<T> StructuralPartialEq for NonZero<T> where T: ZeroablePrimitive + StructuralPartialEq {}
212
213#[stable(feature = "nonzero", since = "1.28.0")]
214#[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
215const impl<T> Eq for NonZero<T> where T: ZeroablePrimitive + [const] Eq {}
216
217#[stable(feature = "nonzero", since = "1.28.0")]
218#[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
219const impl<T> PartialOrd for NonZero<T>
220where
221    T: ZeroablePrimitive + [const] PartialOrd,
222{
223    #[inline]
224    fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
225        self.get().partial_cmp(&other.get())
226    }
227
228    #[inline]
229    fn lt(&self, other: &Self) -> bool {
230        self.get() < other.get()
231    }
232
233    #[inline]
234    fn le(&self, other: &Self) -> bool {
235        self.get() <= other.get()
236    }
237
238    #[inline]
239    fn gt(&self, other: &Self) -> bool {
240        self.get() > other.get()
241    }
242
243    #[inline]
244    fn ge(&self, other: &Self) -> bool {
245        self.get() >= other.get()
246    }
247}
248
249#[stable(feature = "nonzero", since = "1.28.0")]
250#[rustc_const_unstable(feature = "const_cmp", issue = "143800")]
251const impl<T> Ord for NonZero<T>
252where
253    // FIXME(const_hack): the T: ~const Destruct should be inferred from the Self: ~const Destruct.
254    // See https://github.com/rust-lang/rust/issues/144207
255    T: ZeroablePrimitive + [const] Ord + [const] Destruct,
256{
257    #[inline]
258    fn cmp(&self, other: &Self) -> Ordering {
259        self.get().cmp(&other.get())
260    }
261
262    #[inline]
263    fn max(self, other: Self) -> Self {
264        // SAFETY: The maximum of two non-zero values is still non-zero.
265        unsafe { Self::new_unchecked(self.get().max(other.get())) }
266    }
267
268    #[inline]
269    fn min(self, other: Self) -> Self {
270        // SAFETY: The minimum of two non-zero values is still non-zero.
271        unsafe { Self::new_unchecked(self.get().min(other.get())) }
272    }
273
274    #[inline]
275    fn clamp(self, min: Self, max: Self) -> Self {
276        // SAFETY: A non-zero value clamped between two non-zero values is still non-zero.
277        unsafe { Self::new_unchecked(self.get().clamp(min.get(), max.get())) }
278    }
279}
280
281#[stable(feature = "nonzero", since = "1.28.0")]
282impl<T> Hash for NonZero<T>
283where
284    T: ZeroablePrimitive + Hash,
285{
286    #[inline]
287    fn hash<H>(&self, state: &mut H)
288    where
289        H: Hasher,
290    {
291        self.get().hash(state)
292    }
293}
294
295#[stable(feature = "from_nonzero", since = "1.31.0")]
296#[rustc_const_unstable(feature = "const_convert", issue = "143773")]
297const impl<T> From<NonZero<T>> for T
298where
299    T: ZeroablePrimitive,
300{
301    #[inline]
302    fn from(nonzero: NonZero<T>) -> Self {
303        // Call `get` method to keep range information.
304        nonzero.get()
305    }
306}
307
308#[stable(feature = "nonzero_bitor", since = "1.45.0")]
309#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
310const impl<T> BitOr for NonZero<T>
311where
312    T: ZeroablePrimitive + [const] BitOr<Output = T>,
313{
314    type Output = Self;
315
316    #[inline]
317    fn bitor(self, rhs: Self) -> Self::Output {
318        // SAFETY: Bitwise OR of two non-zero values is still non-zero.
319        unsafe { Self::new_unchecked(self.get() | rhs.get()) }
320    }
321}
322
323#[stable(feature = "nonzero_bitor", since = "1.45.0")]
324#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
325const impl<T> BitOr<T> for NonZero<T>
326where
327    T: ZeroablePrimitive + [const] BitOr<Output = T>,
328{
329    type Output = Self;
330
331    #[inline]
332    fn bitor(self, rhs: T) -> Self::Output {
333        // SAFETY: Bitwise OR of a non-zero value with anything is still non-zero.
334        unsafe { Self::new_unchecked(self.get() | rhs) }
335    }
336}
337
338#[stable(feature = "nonzero_bitor", since = "1.45.0")]
339#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
340const impl<T> BitOr<NonZero<T>> for T
341where
342    T: ZeroablePrimitive + [const] BitOr<Output = T>,
343{
344    type Output = NonZero<T>;
345
346    #[inline]
347    fn bitor(self, rhs: NonZero<T>) -> Self::Output {
348        // SAFETY: Bitwise OR of anything with a non-zero value is still non-zero.
349        unsafe { NonZero::new_unchecked(self | rhs.get()) }
350    }
351}
352
353#[stable(feature = "nonzero_bitor", since = "1.45.0")]
354#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
355const impl<T> BitOrAssign for NonZero<T>
356where
357    T: ZeroablePrimitive,
358    Self: [const] BitOr<Output = Self>,
359{
360    #[inline]
361    fn bitor_assign(&mut self, rhs: Self) {
362        *self = *self | rhs;
363    }
364}
365
366#[stable(feature = "nonzero_bitor", since = "1.45.0")]
367#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
368const impl<T> BitOrAssign<T> for NonZero<T>
369where
370    T: ZeroablePrimitive,
371    Self: [const] BitOr<T, Output = Self>,
372{
373    #[inline]
374    fn bitor_assign(&mut self, rhs: T) {
375        *self = *self | rhs;
376    }
377}
378
379impl<T> NonZero<T>
380where
381    T: ZeroablePrimitive,
382{
383    /// Creates a non-zero if the given value is not zero.
384    #[stable(feature = "nonzero", since = "1.28.0")]
385    #[rustc_const_stable(feature = "const_nonzero_int_methods", since = "1.47.0")]
386    #[must_use]
387    #[inline]
388    pub const fn new(n: T) -> Option<Self> {
389        // SAFETY: Memory layout optimization guarantees that `Option<NonZero<T>>` has
390        //         the same layout and size as `T`, with `0` representing `None`.
391        unsafe { intrinsics::transmute_unchecked(n) }
392    }
393
394    /// Creates a non-zero without checking whether the value is non-zero.
395    /// This results in undefined behavior if the value is zero.
396    ///
397    /// # Safety
398    ///
399    /// The value must not be zero.
400    #[stable(feature = "nonzero", since = "1.28.0")]
401    #[rustc_const_stable(feature = "nonzero", since = "1.28.0")]
402    #[must_use]
403    #[inline]
404    #[track_caller]
405    pub const unsafe fn new_unchecked(n: T) -> Self {
406        match Self::new(n) {
407            Some(n) => n,
408            None => {
409                // SAFETY: The caller guarantees that `n` is non-zero, so this is unreachable.
410                unsafe {
411                    ub_checks::assert_unsafe_precondition!(
412                        check_language_ub,
413                        "NonZero::new_unchecked requires the argument to be non-zero",
414                        () => false,
415                    );
416                    intrinsics::unreachable()
417                }
418            }
419        }
420    }
421
422    /// Converts a reference to a non-zero mutable reference
423    /// if the referenced value is not zero.
424    #[unstable(feature = "nonzero_from_mut", issue = "106290")]
425    #[must_use]
426    #[inline]
427    pub fn from_mut(n: &mut T) -> Option<&mut Self> {
428        // SAFETY: Memory layout optimization guarantees that `Option<NonZero<T>>` has
429        //         the same layout and size as `T`, with `0` representing `None`.
430        let opt_n = unsafe { &mut *(ptr::from_mut(n).cast::<Option<Self>>()) };
431
432        opt_n.as_mut()
433    }
434
435    /// Converts a mutable reference to a non-zero mutable reference
436    /// without checking whether the referenced value is non-zero.
437    /// This results in undefined behavior if the referenced value is zero.
438    ///
439    /// # Safety
440    ///
441    /// The referenced value must not be zero.
442    #[unstable(feature = "nonzero_from_mut", issue = "106290")]
443    #[must_use]
444    #[inline]
445    #[track_caller]
446    pub unsafe fn from_mut_unchecked(n: &mut T) -> &mut Self {
447        match Self::from_mut(n) {
448            Some(n) => n,
449            None => {
450                // SAFETY: The caller guarantees that `n` references a value that is non-zero, so this is unreachable.
451                unsafe {
452                    ub_checks::assert_unsafe_precondition!(
453                        check_library_ub,
454                        "NonZero::from_mut_unchecked requires the argument to dereference as non-zero",
455                        () => false,
456                    );
457                    intrinsics::unreachable()
458                }
459            }
460        }
461    }
462
463    /// Returns the contained value as a primitive type.
464    #[stable(feature = "nonzero", since = "1.28.0")]
465    #[rustc_const_stable(feature = "const_nonzero_get", since = "1.34.0")]
466    #[inline]
467    pub const fn get(self) -> T {
468        // Rustc can set range metadata only if it loads `self` from
469        // memory somewhere. If the value of `self` was from by-value argument
470        // of some not-inlined function, LLVM don't have range metadata
471        // to understand that the value cannot be zero.
472        //
473        // Using the transmute `assume`s the range at runtime.
474        //
475        // Even once LLVM supports `!range` metadata for function arguments
476        // (see <https://github.com/llvm/llvm-project/issues/76628>), this can't
477        // be `.0` because MCP#807 bans field-projecting into `scalar_valid_range`
478        // types, and it arguably wouldn't want to be anyway because if this is
479        // MIR-inlined, there's no opportunity to put that argument metadata anywhere.
480        //
481        // The good answer here will eventually be pattern types, which will hopefully
482        // allow it to go back to `.0`, maybe with a cast of some sort.
483        //
484        // SAFETY: `ZeroablePrimitive` guarantees that the size and bit validity
485        // of `.0` is such that this transmute is sound.
486        unsafe { intrinsics::transmute_unchecked(self) }
487    }
488}
489
490macro_rules! nonzero_integer {
491    (
492        #[$stability:meta]
493        Self = $Ty:ident,
494        Primitive = $signedness:ident $Int:ident,
495        SignedPrimitive = $Sint:ty,
496        UnsignedPrimitive = $Uint:ty,
497
498        // Used in doc comments.
499        rot = $rot:literal,
500        rot_op = $rot_op:literal,
501        rot_result = $rot_result:literal,
502        swap_op = $swap_op:literal,
503        swapped = $swapped:literal,
504        reversed = $reversed:literal,
505        leading_zeros_test = $leading_zeros_test:expr,
506    ) => {
507        #[doc = sign_dependent_expr!{
508            $signedness ?
509            if signed {
510                concat!("An [`", stringify!($Int), "`] that is known not to equal zero.")
511            }
512            if unsigned {
513                concat!("A [`", stringify!($Int), "`] that is known not to equal zero.")
514            }
515        }]
516        ///
517        /// This enables some memory layout optimization.
518        #[doc = concat!("For example, `Option<", stringify!($Ty), ">` is the same size as `", stringify!($Int), "`:")]
519        ///
520        /// ```rust
521        #[doc = concat!("assert_eq!(size_of::<Option<core::num::", stringify!($Ty), ">>(), size_of::<", stringify!($Int), ">());")]
522        /// ```
523        ///
524        /// # Layout
525        ///
526        #[doc = concat!("`", stringify!($Ty), "` is guaranteed to have the same layout and bit validity as `", stringify!($Int), "`")]
527        /// with the exception that `0` is not a valid instance.
528        #[doc = concat!("`Option<", stringify!($Ty), ">` is guaranteed to be ABI-compatible with `", stringify!($Int), "`,")]
529        /// including in FFI.
530        ///
531        /// Thanks to the [null pointer optimization],
532        #[doc = concat!("`", stringify!($Ty), "` and `Option<", stringify!($Ty), ">`")]
533        /// are guaranteed to have the same size and alignment:
534        ///
535        /// ```
536        #[doc = concat!("use std::num::", stringify!($Ty), ";")]
537        ///
538        #[doc = concat!("assert_eq!(size_of::<", stringify!($Ty), ">(), size_of::<Option<", stringify!($Ty), ">>());")]
539        #[doc = concat!("assert_eq!(align_of::<", stringify!($Ty), ">(), align_of::<Option<", stringify!($Ty), ">>());")]
540        /// ```
541        ///
542        /// # Compile-time creation
543        ///
544        /// Since both [`Option::unwrap()`] and [`Option::expect()`] are `const`, it is possible to
545        /// define a new
546        #[doc = concat!("`", stringify!($Ty), "`")]
547        /// at compile time via:
548        /// ```
549        #[doc = concat!("use std::num::", stringify!($Ty), ";")]
550        ///
551        #[doc = concat!("const TEN: ", stringify!($Ty), " = ", stringify!($Ty) , r#"::new(10).expect("ten is non-zero");"#)]
552        /// ```
553        ///
554        /// [null pointer optimization]: crate::option#representation
555        #[$stability]
556        pub type $Ty = NonZero<$Int>;
557
558        impl NonZero<$Int> {
559            /// The size of this non-zero integer type in bits.
560            ///
561            #[doc = concat!("This value is equal to [`", stringify!($Int), "::BITS`].")]
562            ///
563            /// # Examples
564            ///
565            /// ```
566            /// # use std::num::NonZero;
567            /// #
568            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::BITS, ", stringify!($Int), "::BITS);")]
569            /// ```
570            #[stable(feature = "nonzero_bits", since = "1.67.0")]
571            pub const BITS: u32 = <$Int>::BITS;
572
573            /// Returns the number of leading zeros in the binary representation of `self`.
574            ///
575            /// On many architectures, this function can perform better than `leading_zeros()` on the underlying integer type, as special handling of zero can be avoided.
576            ///
577            /// # Examples
578            ///
579            /// ```
580            /// # use std::num::NonZero;
581            /// #
582            /// # fn main() { test().unwrap(); }
583            /// # fn test() -> Option<()> {
584            #[doc = concat!("let n = NonZero::<", stringify!($Int), ">::new(", $leading_zeros_test, ")?;")]
585            ///
586            /// assert_eq!(n.leading_zeros(), 0);
587            /// # Some(())
588            /// # }
589            /// ```
590            #[stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
591            #[rustc_const_stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
592            #[must_use = "this returns the result of the operation, \
593                          without modifying the original"]
594            #[inline]
595            pub const fn leading_zeros(self) -> u32 {
596                // SAFETY: since `self` cannot be zero, it is safe to call `ctlz_nonzero`.
597                unsafe {
598                    intrinsics::ctlz_nonzero(self.get() as $Uint)
599                }
600            }
601
602            /// Returns the number of trailing zeros in the binary representation
603            /// of `self`.
604            ///
605            /// On many architectures, this function can perform better than `trailing_zeros()` on the underlying integer type, as special handling of zero can be avoided.
606            ///
607            /// # Examples
608            ///
609            /// ```
610            /// # use std::num::NonZero;
611            /// #
612            /// # fn main() { test().unwrap(); }
613            /// # fn test() -> Option<()> {
614            #[doc = concat!("let n = NonZero::<", stringify!($Int), ">::new(0b0101000)?;")]
615            ///
616            /// assert_eq!(n.trailing_zeros(), 3);
617            /// # Some(())
618            /// # }
619            /// ```
620            #[stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
621            #[rustc_const_stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
622            #[must_use = "this returns the result of the operation, \
623                          without modifying the original"]
624            #[inline]
625            pub const fn trailing_zeros(self) -> u32 {
626                // SAFETY: since `self` cannot be zero, it is safe to call `cttz_nonzero`.
627                unsafe {
628                    intrinsics::cttz_nonzero(self.get() as $Uint)
629                }
630            }
631
632            /// Returns `self` with only the most significant bit set.
633            ///
634            /// # Example
635            ///
636            /// ```
637            /// # use core::num::NonZero;
638            /// # fn main() { test().unwrap(); }
639            /// # fn test() -> Option<()> {
640            #[doc = concat!("let a = NonZero::<", stringify!($Int), ">::new(0b_01100100)?;")]
641            #[doc = concat!("let b = NonZero::<", stringify!($Int), ">::new(0b_01000000)?;")]
642            ///
643            /// assert_eq!(a.isolate_highest_one(), b);
644            /// # Some(())
645            /// # }
646            /// ```
647            #[stable(feature = "isolate_most_least_significant_one", since = "1.97.0")]
648            #[rustc_const_stable(feature = "isolate_most_least_significant_one", since = "1.97.0")]
649            #[must_use = "this returns the result of the operation, \
650                        without modifying the original"]
651            #[inline(always)]
652            pub const fn isolate_highest_one(self) -> Self {
653                // SAFETY:
654                // `self` is non-zero, so masking to preserve only the most
655                // significant set bit will result in a non-zero `n`.
656                // and self.leading_zeros() is always < $INT::BITS since
657                // at least one of the bits in the number is not zero
658                unsafe {
659                    let bit = (((1 as $Uint) << (<$Uint>::BITS - 1)).unchecked_shr(self.leading_zeros()));
660                    NonZero::new_unchecked(bit as $Int)
661                }
662            }
663
664            /// Returns `self` with only the least significant bit set.
665            ///
666            /// # Example
667            ///
668            /// ```
669            /// # use core::num::NonZero;
670            /// # fn main() { test().unwrap(); }
671            /// # fn test() -> Option<()> {
672            #[doc = concat!("let a = NonZero::<", stringify!($Int), ">::new(0b_01100100)?;")]
673            #[doc = concat!("let b = NonZero::<", stringify!($Int), ">::new(0b_00000100)?;")]
674            ///
675            /// assert_eq!(a.isolate_lowest_one(), b);
676            /// # Some(())
677            /// # }
678            /// ```
679            #[stable(feature = "isolate_most_least_significant_one", since = "1.97.0")]
680            #[rustc_const_stable(feature = "isolate_most_least_significant_one", since = "1.97.0")]
681            #[must_use = "this returns the result of the operation, \
682                        without modifying the original"]
683            #[inline(always)]
684            pub const fn isolate_lowest_one(self) -> Self {
685                let n = self.get();
686                let n = n & n.wrapping_neg();
687
688                // SAFETY: `self` is non-zero, so `self` with only its least
689                // significant set bit will remain non-zero.
690                unsafe { NonZero::new_unchecked(n) }
691            }
692
693            /// Returns the index of the highest bit set to one in `self`.
694            ///
695            #[doc = sign_dependent_expr!{
696                $signedness ?
697                if signed {
698                    ""
699                }
700                if unsigned {
701                    "Note that this is equivalent to [`ilog2`](Self::ilog2)."
702                }
703            }]
704            ///
705            /// # Examples
706            ///
707            /// ```
708            /// # use core::num::NonZero;
709            /// # fn main() { test().unwrap(); }
710            /// # fn test() -> Option<()> {
711            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1)?.highest_one(), 0);")]
712            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1_0000)?.highest_one(), 4);")]
713            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1_1111)?.highest_one(), 4);")]
714            /// # Some(())
715            /// # }
716            /// ```
717            #[stable(feature = "int_lowest_highest_one", since = "1.97.0")]
718            #[rustc_const_stable(feature = "int_lowest_highest_one", since = "1.97.0")]
719            #[must_use = "this returns the result of the operation, \
720                          without modifying the original"]
721            #[inline(always)]
722            pub const fn highest_one(self) -> u32 {
723                Self::BITS - 1 - self.leading_zeros()
724            }
725
726            /// Returns the index of the lowest bit set to one in `self`.
727            ///
728            /// # Examples
729            ///
730            /// ```
731            /// # use core::num::NonZero;
732            /// # fn main() { test().unwrap(); }
733            /// # fn test() -> Option<()> {
734            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1)?.lowest_one(), 0);")]
735            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1_0000)?.lowest_one(), 4);")]
736            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1_1111)?.lowest_one(), 0);")]
737            /// # Some(())
738            /// # }
739            /// ```
740            #[stable(feature = "int_lowest_highest_one", since = "1.97.0")]
741            #[rustc_const_stable(feature = "int_lowest_highest_one", since = "1.97.0")]
742            #[must_use = "this returns the result of the operation, \
743                          without modifying the original"]
744            #[inline(always)]
745            pub const fn lowest_one(self) -> u32 {
746                self.trailing_zeros()
747            }
748
749            /// Returns the number of ones in the binary representation of `self`.
750            ///
751            /// # Examples
752            ///
753            /// ```
754            /// # use std::num::NonZero;
755            /// #
756            /// # fn main() { test().unwrap(); }
757            /// # fn test() -> Option<()> {
758            #[doc = concat!("let a = NonZero::<", stringify!($Int), ">::new(0b100_0000)?;")]
759            #[doc = concat!("let b = NonZero::<", stringify!($Int), ">::new(0b100_0011)?;")]
760            ///
761            /// assert_eq!(a.count_ones(), NonZero::new(1)?);
762            /// assert_eq!(b.count_ones(), NonZero::new(3)?);
763            /// # Some(())
764            /// # }
765            /// ```
766            ///
767            #[stable(feature = "non_zero_count_ones", since = "1.86.0")]
768            #[rustc_const_stable(feature = "non_zero_count_ones", since = "1.86.0")]
769            #[doc(alias = "popcount")]
770            #[doc(alias = "popcnt")]
771            #[must_use = "this returns the result of the operation, \
772                        without modifying the original"]
773            #[inline(always)]
774            pub const fn count_ones(self) -> NonZero<u32> {
775                // SAFETY:
776                // `self` is non-zero, which means it has at least one bit set, which means
777                // that the result of `count_ones` is non-zero.
778                unsafe { NonZero::new_unchecked(self.get().count_ones()) }
779            }
780
781            /// Shifts the bits to the left by a specified amount, `n`,
782            /// wrapping the truncated bits to the end of the resulting integer.
783            ///
784            /// Please note this isn't the same operation as the `<<` shifting operator!
785            ///
786            /// # Examples
787            ///
788            /// ```
789            /// #![feature(nonzero_bitwise)]
790            /// # use std::num::NonZero;
791            /// #
792            /// # fn main() { test().unwrap(); }
793            /// # fn test() -> Option<()> {
794            #[doc = concat!("let n = NonZero::new(", $rot_op, stringify!($Int), ")?;")]
795            #[doc = concat!("let m = NonZero::new(", $rot_result, ")?;")]
796            ///
797            #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
798            /// # Some(())
799            /// # }
800            /// ```
801            #[unstable(feature = "nonzero_bitwise", issue = "128281")]
802            #[must_use = "this returns the result of the operation, \
803                        without modifying the original"]
804            #[inline(always)]
805            pub const fn rotate_left(self, n: u32) -> Self {
806                let result = self.get().rotate_left(n);
807                // SAFETY: Rotating bits preserves the property int > 0.
808                unsafe { Self::new_unchecked(result) }
809            }
810
811            /// Shifts the bits to the right by a specified amount, `n`,
812            /// wrapping the truncated bits to the beginning of the resulting
813            /// integer.
814            ///
815            /// Please note this isn't the same operation as the `>>` shifting operator!
816            ///
817            /// # Examples
818            ///
819            /// ```
820            /// #![feature(nonzero_bitwise)]
821            /// # use std::num::NonZero;
822            /// #
823            /// # fn main() { test().unwrap(); }
824            /// # fn test() -> Option<()> {
825            #[doc = concat!("let n = NonZero::new(", $rot_result, stringify!($Int), ")?;")]
826            #[doc = concat!("let m = NonZero::new(", $rot_op, ")?;")]
827            ///
828            #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
829            /// # Some(())
830            /// # }
831            /// ```
832            #[unstable(feature = "nonzero_bitwise", issue = "128281")]
833            #[must_use = "this returns the result of the operation, \
834                        without modifying the original"]
835            #[inline(always)]
836            pub const fn rotate_right(self, n: u32) -> Self {
837                let result = self.get().rotate_right(n);
838                // SAFETY: Rotating bits preserves the property int > 0.
839                unsafe { Self::new_unchecked(result) }
840            }
841
842            /// Reverses the byte order of the integer.
843            ///
844            /// # Examples
845            ///
846            /// ```
847            /// #![feature(nonzero_bitwise)]
848            /// # use std::num::NonZero;
849            /// #
850            /// # fn main() { test().unwrap(); }
851            /// # fn test() -> Option<()> {
852            #[doc = concat!("let n = NonZero::new(", $swap_op, stringify!($Int), ")?;")]
853            /// let m = n.swap_bytes();
854            ///
855            #[doc = concat!("assert_eq!(m, NonZero::new(", $swapped, ")?);")]
856            /// # Some(())
857            /// # }
858            /// ```
859            #[unstable(feature = "nonzero_bitwise", issue = "128281")]
860            #[must_use = "this returns the result of the operation, \
861                        without modifying the original"]
862            #[inline(always)]
863            pub const fn swap_bytes(self) -> Self {
864                let result = self.get().swap_bytes();
865                // SAFETY: Shuffling bytes preserves the property int > 0.
866                unsafe { Self::new_unchecked(result) }
867            }
868
869            /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
870            /// second least-significant bit becomes second most-significant bit, etc.
871            ///
872            /// # Examples
873            ///
874            /// ```
875            /// #![feature(nonzero_bitwise)]
876            /// # use std::num::NonZero;
877            /// #
878            /// # fn main() { test().unwrap(); }
879            /// # fn test() -> Option<()> {
880            #[doc = concat!("let n = NonZero::new(", $swap_op, stringify!($Int), ")?;")]
881            /// let m = n.reverse_bits();
882            ///
883            #[doc = concat!("assert_eq!(m, NonZero::new(", $reversed, ")?);")]
884            /// # Some(())
885            /// # }
886            /// ```
887            #[unstable(feature = "nonzero_bitwise", issue = "128281")]
888            #[must_use = "this returns the result of the operation, \
889                        without modifying the original"]
890            #[inline(always)]
891            pub const fn reverse_bits(self) -> Self {
892                let result = self.get().reverse_bits();
893                // SAFETY: Reversing bits preserves the property int > 0.
894                unsafe { Self::new_unchecked(result) }
895            }
896
897            /// Converts an integer from big endian to the target's endianness.
898            ///
899            /// On big endian this is a no-op. On little endian the bytes are
900            /// swapped.
901            ///
902            /// # Examples
903            ///
904            /// ```
905            /// #![feature(nonzero_bitwise)]
906            /// # use std::num::NonZero;
907            #[doc = concat!("use std::num::", stringify!($Ty), ";")]
908            /// #
909            /// # fn main() { test().unwrap(); }
910            /// # fn test() -> Option<()> {
911            #[doc = concat!("let n = NonZero::new(0x1A", stringify!($Int), ")?;")]
912            ///
913            /// if cfg!(target_endian = "big") {
914            #[doc = concat!("    assert_eq!(", stringify!($Ty), "::from_be(n), n)")]
915            /// } else {
916            #[doc = concat!("    assert_eq!(", stringify!($Ty), "::from_be(n), n.swap_bytes())")]
917            /// }
918            /// # Some(())
919            /// # }
920            /// ```
921            #[unstable(feature = "nonzero_bitwise", issue = "128281")]
922            #[must_use]
923            #[inline(always)]
924            pub const fn from_be(x: Self) -> Self {
925                let result = $Int::from_be(x.get());
926                // SAFETY: Shuffling bytes preserves the property int > 0.
927                unsafe { Self::new_unchecked(result) }
928            }
929
930            /// Converts an integer from little endian to the target's endianness.
931            ///
932            /// On little endian this is a no-op. On big endian the bytes are
933            /// swapped.
934            ///
935            /// # Examples
936            ///
937            /// ```
938            /// #![feature(nonzero_bitwise)]
939            /// # use std::num::NonZero;
940            #[doc = concat!("use std::num::", stringify!($Ty), ";")]
941            /// #
942            /// # fn main() { test().unwrap(); }
943            /// # fn test() -> Option<()> {
944            #[doc = concat!("let n = NonZero::new(0x1A", stringify!($Int), ")?;")]
945            ///
946            /// if cfg!(target_endian = "little") {
947            #[doc = concat!("    assert_eq!(", stringify!($Ty), "::from_le(n), n)")]
948            /// } else {
949            #[doc = concat!("    assert_eq!(", stringify!($Ty), "::from_le(n), n.swap_bytes())")]
950            /// }
951            /// # Some(())
952            /// # }
953            /// ```
954            #[unstable(feature = "nonzero_bitwise", issue = "128281")]
955            #[must_use]
956            #[inline(always)]
957            pub const fn from_le(x: Self) -> Self {
958                let result = $Int::from_le(x.get());
959                // SAFETY: Shuffling bytes preserves the property int > 0.
960                unsafe { Self::new_unchecked(result) }
961            }
962
963            /// Converts `self` to big endian from the target's endianness.
964            ///
965            /// On big endian this is a no-op. On little endian the bytes are
966            /// swapped.
967            ///
968            /// # Examples
969            ///
970            /// ```
971            /// #![feature(nonzero_bitwise)]
972            /// # use std::num::NonZero;
973            /// #
974            /// # fn main() { test().unwrap(); }
975            /// # fn test() -> Option<()> {
976            #[doc = concat!("let n = NonZero::new(0x1A", stringify!($Int), ")?;")]
977            ///
978            /// if cfg!(target_endian = "big") {
979            ///     assert_eq!(n.to_be(), n)
980            /// } else {
981            ///     assert_eq!(n.to_be(), n.swap_bytes())
982            /// }
983            /// # Some(())
984            /// # }
985            /// ```
986            #[unstable(feature = "nonzero_bitwise", issue = "128281")]
987            #[must_use = "this returns the result of the operation, \
988                        without modifying the original"]
989            #[inline(always)]
990            pub const fn to_be(self) -> Self {
991                let result = self.get().to_be();
992                // SAFETY: Shuffling bytes preserves the property int > 0.
993                unsafe { Self::new_unchecked(result) }
994            }
995
996            /// Converts `self` to little endian from the target's endianness.
997            ///
998            /// On little endian this is a no-op. On big endian the bytes are
999            /// swapped.
1000            ///
1001            /// # Examples
1002            ///
1003            /// ```
1004            /// #![feature(nonzero_bitwise)]
1005            /// # use std::num::NonZero;
1006            /// #
1007            /// # fn main() { test().unwrap(); }
1008            /// # fn test() -> Option<()> {
1009            #[doc = concat!("let n = NonZero::new(0x1A", stringify!($Int), ")?;")]
1010            ///
1011            /// if cfg!(target_endian = "little") {
1012            ///     assert_eq!(n.to_le(), n)
1013            /// } else {
1014            ///     assert_eq!(n.to_le(), n.swap_bytes())
1015            /// }
1016            /// # Some(())
1017            /// # }
1018            /// ```
1019            #[unstable(feature = "nonzero_bitwise", issue = "128281")]
1020            #[must_use = "this returns the result of the operation, \
1021                        without modifying the original"]
1022            #[inline(always)]
1023            pub const fn to_le(self) -> Self {
1024                let result = self.get().to_le();
1025                // SAFETY: Shuffling bytes preserves the property int > 0.
1026                unsafe { Self::new_unchecked(result) }
1027            }
1028
1029            nonzero_integer_signedness_dependent_methods! {
1030                Primitive = $signedness $Int,
1031                SignedPrimitive = $Sint,
1032                UnsignedPrimitive = $Uint,
1033            }
1034
1035            /// Multiplies two non-zero integers together.
1036            /// Checks for overflow and returns [`None`] on overflow.
1037            /// As a consequence, the result cannot wrap to zero.
1038            ///
1039            /// # Examples
1040            ///
1041            /// ```
1042            /// # use std::num::NonZero;
1043            /// #
1044            /// # fn main() { test().unwrap(); }
1045            /// # fn test() -> Option<()> {
1046            #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1047            #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1048            #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1049            ///
1050            /// assert_eq!(Some(four), two.checked_mul(two));
1051            /// assert_eq!(None, max.checked_mul(two));
1052            /// # Some(())
1053            /// # }
1054            /// ```
1055            #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1056            #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1057            #[must_use = "this returns the result of the operation, \
1058                          without modifying the original"]
1059            #[inline]
1060            pub const fn checked_mul(self, other: Self) -> Option<Self> {
1061                if let Some(result) = self.get().checked_mul(other.get()) {
1062                    // SAFETY:
1063                    // - `checked_mul` returns `None` on overflow
1064                    // - `self` and `other` are non-zero
1065                    // - the only way to get zero from a multiplication without overflow is for one
1066                    //   of the sides to be zero
1067                    //
1068                    // So the result cannot be zero.
1069                    Some(unsafe { Self::new_unchecked(result) })
1070                } else {
1071                    None
1072                }
1073            }
1074
1075            /// Multiplies two non-zero integers together.
1076            #[doc = concat!("Return [`NonZero::<", stringify!($Int), ">::MAX`] on overflow.")]
1077            ///
1078            /// # Examples
1079            ///
1080            /// ```
1081            /// # use std::num::NonZero;
1082            /// #
1083            /// # fn main() { test().unwrap(); }
1084            /// # fn test() -> Option<()> {
1085            #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1086            #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1087            #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1088            ///
1089            /// assert_eq!(four, two.saturating_mul(two));
1090            /// assert_eq!(max, four.saturating_mul(max));
1091            /// # Some(())
1092            /// # }
1093            /// ```
1094            #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1095            #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1096            #[must_use = "this returns the result of the operation, \
1097                          without modifying the original"]
1098            #[inline]
1099            pub const fn saturating_mul(self, other: Self) -> Self {
1100                // SAFETY:
1101                // - `saturating_mul` returns `u*::MAX`/`i*::MAX`/`i*::MIN` on overflow/underflow,
1102                //   all of which are non-zero
1103                // - `self` and `other` are non-zero
1104                // - the only way to get zero from a multiplication without overflow is for one
1105                //   of the sides to be zero
1106                //
1107                // So the result cannot be zero.
1108                unsafe { Self::new_unchecked(self.get().saturating_mul(other.get())) }
1109            }
1110
1111            /// Multiplies two non-zero integers together,
1112            /// assuming overflow cannot occur.
1113            /// Overflow is unchecked, and it is undefined behavior to overflow
1114            /// *even if the result would wrap to a non-zero value*.
1115            ///
1116            /// # Safety
1117            ///
1118            /// This results in undefined behavior when
1119            #[doc = sign_dependent_expr!{
1120                $signedness ?
1121                if signed {
1122                    concat!("`self * rhs > ", stringify!($Int), "::MAX`, ",
1123                            "or `self * rhs < ", stringify!($Int), "::MIN`.")
1124                }
1125                if unsigned {
1126                    concat!("`self * rhs > ", stringify!($Int), "::MAX`.")
1127                }
1128            }]
1129            ///
1130            /// # Examples
1131            ///
1132            /// ```
1133            /// #![feature(nonzero_ops)]
1134            ///
1135            /// # use std::num::NonZero;
1136            /// #
1137            /// # fn main() { test().unwrap(); }
1138            /// # fn test() -> Option<()> {
1139            #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1140            #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1141            ///
1142            /// assert_eq!(four, unsafe { two.unchecked_mul(two) });
1143            /// # Some(())
1144            /// # }
1145            /// ```
1146            #[unstable(feature = "nonzero_ops", issue = "84186")]
1147            #[must_use = "this returns the result of the operation, \
1148                          without modifying the original"]
1149            #[inline]
1150            pub const unsafe fn unchecked_mul(self, other: Self) -> Self {
1151                // SAFETY: The caller ensures there is no overflow.
1152                unsafe { Self::new_unchecked(self.get().unchecked_mul(other.get())) }
1153            }
1154
1155            /// Raises non-zero value to an integer power.
1156            /// Checks for overflow and returns [`None`] on overflow.
1157            /// As a consequence, the result cannot wrap to zero.
1158            ///
1159            /// # Examples
1160            ///
1161            /// ```
1162            /// # use std::num::NonZero;
1163            /// #
1164            /// # fn main() { test().unwrap(); }
1165            /// # fn test() -> Option<()> {
1166            #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ")?;")]
1167            #[doc = concat!("let twenty_seven = NonZero::new(27", stringify!($Int), ")?;")]
1168            #[doc = concat!("let half_max = NonZero::new(", stringify!($Int), "::MAX / 2)?;")]
1169            ///
1170            /// assert_eq!(Some(twenty_seven), three.checked_pow(3));
1171            /// assert_eq!(None, half_max.checked_pow(3));
1172            /// # Some(())
1173            /// # }
1174            /// ```
1175            #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1176            #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1177            #[must_use = "this returns the result of the operation, \
1178                          without modifying the original"]
1179            #[inline]
1180            pub const fn checked_pow(self, other: u32) -> Option<Self> {
1181                if let Some(result) = self.get().checked_pow(other) {
1182                    // SAFETY:
1183                    // - `checked_pow` returns `None` on overflow/underflow
1184                    // - `self` is non-zero
1185                    // - the only way to get zero from an exponentiation without overflow is
1186                    //   for base to be zero
1187                    //
1188                    // So the result cannot be zero.
1189                    Some(unsafe { Self::new_unchecked(result) })
1190                } else {
1191                    None
1192                }
1193            }
1194
1195            /// Raise non-zero value to an integer power.
1196            #[doc = sign_dependent_expr!{
1197                $signedness ?
1198                if signed {
1199                    concat!("Return [`NonZero::<", stringify!($Int), ">::MIN`] ",
1200                                "or [`NonZero::<", stringify!($Int), ">::MAX`] on overflow.")
1201                }
1202                if unsigned {
1203                    concat!("Return [`NonZero::<", stringify!($Int), ">::MAX`] on overflow.")
1204                }
1205            }]
1206            ///
1207            /// # Examples
1208            ///
1209            /// ```
1210            /// # use std::num::NonZero;
1211            /// #
1212            /// # fn main() { test().unwrap(); }
1213            /// # fn test() -> Option<()> {
1214            #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ")?;")]
1215            #[doc = concat!("let twenty_seven = NonZero::new(27", stringify!($Int), ")?;")]
1216            #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1217            ///
1218            /// assert_eq!(twenty_seven, three.saturating_pow(3));
1219            /// assert_eq!(max, max.saturating_pow(3));
1220            /// # Some(())
1221            /// # }
1222            /// ```
1223            #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1224            #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1225            #[must_use = "this returns the result of the operation, \
1226                          without modifying the original"]
1227            #[inline]
1228            pub const fn saturating_pow(self, other: u32) -> Self {
1229                // SAFETY:
1230                // - `saturating_pow` returns `u*::MAX`/`i*::MAX`/`i*::MIN` on overflow/underflow,
1231                //   all of which are non-zero
1232                // - `self` is non-zero
1233                // - the only way to get zero from an exponentiation without overflow is
1234                //   for base to be zero
1235                //
1236                // So the result cannot be zero.
1237                unsafe { Self::new_unchecked(self.get().saturating_pow(other)) }
1238            }
1239
1240            /// Parses a non-zero integer from an ASCII-byte slice with decimal digits.
1241            ///
1242            /// The characters are expected to be an optional
1243            #[doc = sign_dependent_expr!{
1244                $signedness ?
1245                if signed {
1246                    " `+` or `-` "
1247                }
1248                if unsigned {
1249                    " `+` "
1250                }
1251            }]
1252            /// sign followed by only digits. Leading and trailing non-digit characters (including
1253            /// whitespace) represent an error. Underscores (which are accepted in Rust literals)
1254            /// also represent an error.
1255            ///
1256            /// # Examples
1257            ///
1258            /// ```
1259            /// #![feature(int_from_ascii)]
1260            ///
1261            /// # use std::num::NonZero;
1262            /// #
1263            /// # fn main() { test().unwrap(); }
1264            /// # fn test() -> Option<()> {
1265            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::from_ascii_bytes(b\"+10\"), Ok(NonZero::new(10)?));")]
1266            /// # Some(())
1267            /// # }
1268            /// ```
1269            ///
1270            /// Trailing space returns error:
1271            ///
1272            /// ```
1273            /// #![feature(int_from_ascii)]
1274            ///
1275            /// # use std::num::NonZero;
1276            /// #
1277            #[doc = concat!("assert!(NonZero::<", stringify!($Int), ">::from_ascii_bytes(b\"1 \").is_err());")]
1278            /// ```
1279            #[unstable(feature = "int_from_ascii", issue = "134821")]
1280            #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
1281            #[inline]
1282            pub const fn from_ascii_bytes<T>(src: T) -> Result<Self, ParseIntError>
1283            where
1284                T: [const] AsRef<[u8]> + [const] crate::marker::Destruct
1285            {
1286                Self::from_ascii_bytes_radix_impl(src.as_ref(), 10)
1287            }
1288
1289            /// Parses a non-zero integer from an ASCII-byte slice with digits in a given base.
1290            ///
1291            /// The characters are expected to be an optional
1292            #[doc = sign_dependent_expr!{
1293                $signedness ?
1294                if signed {
1295                    " `+` or `-` "
1296                }
1297                if unsigned {
1298                    " `+` "
1299                }
1300            }]
1301            /// sign followed by only digits. Leading and trailing non-digit characters (including
1302            /// whitespace) represent an error. Underscores (which are accepted in Rust literals)
1303            /// also represent an error.
1304            ///
1305            /// Digits are a subset of these characters, depending on `radix`:
1306            ///
1307            /// - `0-9`
1308            /// - `a-z`
1309            /// - `A-Z`
1310            ///
1311            /// # Panics
1312            ///
1313            /// This method panics if `radix` is not in the range from 2 to 36.
1314            ///
1315            /// # Examples
1316            ///
1317            /// ```
1318            /// #![feature(int_from_ascii)]
1319            ///
1320            /// # use std::num::NonZero;
1321            /// #
1322            /// # fn main() { test().unwrap(); }
1323            /// # fn test() -> Option<()> {
1324            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::from_ascii_bytes_radix(b\"A\", 16), Ok(NonZero::new(10)?));")]
1325            /// # Some(())
1326            /// # }
1327            /// ```
1328            ///
1329            /// Trailing space returns error:
1330            ///
1331            /// ```
1332            /// #![feature(int_from_ascii)]
1333            ///
1334            /// # use std::num::NonZero;
1335            /// #
1336            #[doc = concat!("assert!(NonZero::<", stringify!($Int), ">::from_ascii_bytes_radix(b\"1 \", 10).is_err());")]
1337            /// ```
1338            #[unstable(feature = "int_from_ascii", issue = "134821")]
1339            #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
1340            #[inline]
1341            pub const fn from_ascii_bytes_radix<T>(src: T, radix: u32) -> Result<Self, ParseIntError>
1342            where
1343                T: [const] AsRef<[u8]> + [const] crate::marker::Destruct
1344            {
1345                Self::from_ascii_bytes_radix_impl(src.as_ref(), radix)
1346            }
1347
1348            #[inline]
1349            const fn from_ascii_bytes_radix_impl(src: &[u8], radix: u32) -> Result<Self, ParseIntError> {
1350                let n = match <$Int>::from_ascii_bytes_radix_impl(src, radix) {
1351                    Ok(n) => n,
1352                    Err(err) => return Err(err),
1353                };
1354                if let Some(n) = Self::new(n) {
1355                    Ok(n)
1356                } else {
1357                    Err(ParseIntError { kind: IntErrorKind::Zero })
1358                }
1359            }
1360
1361            /// Parses a non-zero integer from a string slice with digits in a given base.
1362            ///
1363            /// The string is expected to be an optional
1364            #[doc = sign_dependent_expr!{
1365                $signedness ?
1366                if signed {
1367                    " `+` or `-` "
1368                }
1369                if unsigned {
1370                    " `+` "
1371                }
1372            }]
1373            /// sign followed by only digits. Leading and trailing non-digit characters (including
1374            /// whitespace) represent an error. Underscores (which are accepted in Rust literals)
1375            /// also represent an error.
1376            ///
1377            /// Digits are a subset of these characters, depending on `radix`:
1378            ///
1379            /// - `0-9`
1380            /// - `a-z`
1381            /// - `A-Z`
1382            ///
1383            /// # Panics
1384            ///
1385            /// This method panics if `radix` is not in the range from 2 to 36.
1386            ///
1387            /// # Examples
1388            ///
1389            /// ```
1390            /// # use std::num::NonZero;
1391            /// #
1392            /// # fn main() { test().unwrap(); }
1393            /// # fn test() -> Option<()> {
1394            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::from_str_radix(\"A\", 16), Ok(NonZero::new(10)?));")]
1395            /// # Some(())
1396            /// # }
1397            /// ```
1398            ///
1399            /// Trailing space returns error:
1400            ///
1401            /// ```
1402            /// # use std::num::NonZero;
1403            /// #
1404            #[doc = concat!("assert!(NonZero::<", stringify!($Int), ">::from_str_radix(\"1 \", 10).is_err());")]
1405            /// ```
1406            #[stable(feature = "nonzero_from_str_radix", since = "1.98.0")]
1407            #[rustc_const_stable(feature = "nonzero_from_str_radix", since = "1.98.0")]
1408            #[inline]
1409            pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> {
1410                Self::from_ascii_bytes_radix_impl(src.as_bytes(), radix)
1411            }
1412        }
1413
1414        #[stable(feature = "nonzero_parse", since = "1.35.0")]
1415        #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
1416        const impl FromStr for NonZero<$Int> {
1417            type Err = ParseIntError;
1418
1419            /// Parses a non-zero integer from a string slice with decimal digits.
1420            ///
1421            /// The characters are expected to be an optional
1422            #[doc = sign_dependent_expr!{
1423                $signedness ?
1424                if signed {
1425                    " `+` or `-` "
1426                }
1427                if unsigned {
1428                    " `+` "
1429                }
1430            }]
1431            /// sign followed by only digits. Leading and trailing non-digit characters (including
1432            /// whitespace) represent an error. Underscores (which are accepted in Rust literals)
1433            /// also represent an error.
1434            ///
1435            /// # Examples
1436            ///
1437            /// ```
1438            /// use std::num::NonZero;
1439            /// use std::str::FromStr;
1440            ///
1441            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::from_str(\"+10\"), Ok(NonZero::new(10).unwrap()));")]
1442            /// ```
1443            ///
1444            /// Trailing space returns error:
1445            ///
1446            /// ```
1447            /// use std::num::NonZero;
1448            /// use std::str::FromStr;
1449            ///
1450            #[doc = concat!("assert!(NonZero::<", stringify!($Int), ">::from_str(\"1 \").is_err());")]
1451            /// ```
1452            fn from_str(src: &str) -> Result<Self, Self::Err> {
1453                Self::from_str_radix(src, 10)
1454            }
1455        }
1456
1457        nonzero_integer_signedness_dependent_impls!($signedness $Int);
1458    };
1459
1460    (
1461        Self = $Ty:ident,
1462        Primitive = unsigned $Int:ident,
1463        SignedPrimitive = $Sint:ident,
1464        rot = $rot:literal,
1465        rot_op = $rot_op:literal,
1466        rot_result = $rot_result:literal,
1467        swap_op = $swap_op:literal,
1468        swapped = $swapped:literal,
1469        reversed = $reversed:literal,
1470        $(,)?
1471    ) => {
1472        nonzero_integer! {
1473            #[stable(feature = "nonzero", since = "1.28.0")]
1474            Self = $Ty,
1475            Primitive = unsigned $Int,
1476            SignedPrimitive = $Sint,
1477            UnsignedPrimitive = $Int,
1478            rot = $rot,
1479            rot_op = $rot_op,
1480            rot_result = $rot_result,
1481            swap_op = $swap_op,
1482            swapped = $swapped,
1483            reversed = $reversed,
1484            leading_zeros_test = concat!(stringify!($Int), "::MAX"),
1485        }
1486    };
1487
1488    (
1489        Self = $Ty:ident,
1490        Primitive = signed $Int:ident,
1491        UnsignedPrimitive = $Uint:ident,
1492        rot = $rot:literal,
1493        rot_op = $rot_op:literal,
1494        rot_result = $rot_result:literal,
1495        swap_op = $swap_op:literal,
1496        swapped = $swapped:literal,
1497        reversed = $reversed:literal,
1498    ) => {
1499        nonzero_integer! {
1500            #[stable(feature = "signed_nonzero", since = "1.34.0")]
1501            Self = $Ty,
1502            Primitive = signed $Int,
1503            SignedPrimitive = $Int,
1504            UnsignedPrimitive = $Uint,
1505            rot = $rot,
1506            rot_op = $rot_op,
1507            rot_result = $rot_result,
1508            swap_op = $swap_op,
1509            swapped = $swapped,
1510            reversed = $reversed,
1511            leading_zeros_test = concat!("-1", stringify!($Int)),
1512        }
1513    };
1514}
1515
1516macro_rules! nonzero_integer_signedness_dependent_impls {
1517    // Impls for unsigned nonzero types only.
1518    (unsigned $Int:ty) => {
1519        #[stable(feature = "nonzero_div", since = "1.51.0")]
1520        #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1521        const impl Div<NonZero<$Int>> for $Int {
1522            type Output = $Int;
1523
1524            /// Same as `self / other.get()`, but because `other` is a `NonZero<_>`,
1525            /// there's never a runtime check for division-by-zero.
1526            ///
1527            /// This operation rounds towards zero, truncating any fractional
1528            /// part of the exact result, and cannot panic.
1529            #[doc(alias = "unchecked_div")]
1530            #[inline]
1531            fn div(self, other: NonZero<$Int>) -> $Int {
1532                // SAFETY: Division by zero is checked because `other` is non-zero,
1533                // and MIN/-1 is checked because `self` is an unsigned int.
1534                unsafe { intrinsics::unchecked_div(self, other.get()) }
1535            }
1536        }
1537
1538        #[stable(feature = "nonzero_div_assign", since = "1.79.0")]
1539        #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1540        const impl DivAssign<NonZero<$Int>> for $Int {
1541            /// Same as `self /= other.get()`, but because `other` is a `NonZero<_>`,
1542            /// there's never a runtime check for division-by-zero.
1543            ///
1544            /// This operation rounds towards zero, truncating any fractional
1545            /// part of the exact result, and cannot panic.
1546            #[inline]
1547            fn div_assign(&mut self, other: NonZero<$Int>) {
1548                *self = *self / other;
1549            }
1550        }
1551
1552        #[stable(feature = "nonzero_div", since = "1.51.0")]
1553        #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1554        const impl Rem<NonZero<$Int>> for $Int {
1555            type Output = $Int;
1556
1557            /// This operation satisfies `n % d == n - (n / d) * d`, and cannot panic.
1558            #[inline]
1559            fn rem(self, other: NonZero<$Int>) -> $Int {
1560                // SAFETY: Remainder by zero is checked because `other` is non-zero,
1561                // and MIN/-1 is checked because `self` is an unsigned int.
1562                unsafe { intrinsics::unchecked_rem(self, other.get()) }
1563            }
1564        }
1565
1566        #[stable(feature = "nonzero_div_assign", since = "1.79.0")]
1567        #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1568        const impl RemAssign<NonZero<$Int>> for $Int {
1569            /// This operation satisfies `n % d == n - (n / d) * d`, and cannot panic.
1570            #[inline]
1571            fn rem_assign(&mut self, other: NonZero<$Int>) {
1572                *self = *self % other;
1573            }
1574        }
1575
1576        impl NonZero<$Int> {
1577            /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
1578            ///
1579            /// The result is guaranteed to be non-zero.
1580            ///
1581            /// # Examples
1582            ///
1583            /// ```
1584            /// # use std::num::NonZero;
1585            #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ").unwrap();")]
1586            #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX).unwrap();")]
1587            /// assert_eq!(one.div_ceil(max), one);
1588            ///
1589            #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ").unwrap();")]
1590            #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ").unwrap();")]
1591            /// assert_eq!(three.div_ceil(two), two);
1592            /// ```
1593            #[stable(feature = "unsigned_nonzero_div_ceil", since = "1.92.0")]
1594            #[rustc_const_stable(feature = "unsigned_nonzero_div_ceil", since = "1.92.0")]
1595            #[must_use = "this returns the result of the operation, \
1596                          without modifying the original"]
1597            #[inline]
1598            pub const fn div_ceil(self, rhs: Self) -> Self {
1599                // An implementation of the function without calculating the remainder.
1600                // It is better than the implementation for normal integers, but it can only
1601                // be used here because of the possibility to subtract by one without overflow.
1602                let v = (self.get() - 1) / rhs.get() + 1;
1603                // SAFETY: ceiled division of two positive integers can never be zero.
1604                unsafe { Self::new_unchecked(v) }
1605            }
1606        }
1607    };
1608    // Impls for signed nonzero types only.
1609    (signed $Int:ty) => {
1610        #[stable(feature = "signed_nonzero_neg", since = "1.71.0")]
1611        #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1612        const impl Neg for NonZero<$Int> {
1613            type Output = Self;
1614
1615            #[inline]
1616            fn neg(self) -> Self {
1617                // SAFETY: negation of nonzero cannot yield zero values.
1618                unsafe { Self::new_unchecked(self.get().neg()) }
1619            }
1620        }
1621
1622        forward_ref_unop! { impl Neg, neg for NonZero<$Int>,
1623        #[stable(feature = "signed_nonzero_neg", since = "1.71.0")]
1624        #[rustc_const_unstable(feature = "const_ops", issue = "143802")] }
1625    };
1626}
1627
1628#[rustfmt::skip] // https://github.com/rust-lang/rustfmt/issues/5974
1629macro_rules! nonzero_integer_signedness_dependent_methods {
1630    // Associated items for unsigned nonzero types only.
1631    (
1632        Primitive = unsigned $Int:ident,
1633        SignedPrimitive = $Sint:ty,
1634        UnsignedPrimitive = $Uint:ty,
1635    ) => {
1636        /// The smallest value that can be represented by this non-zero
1637        /// integer type, 1.
1638        ///
1639        /// # Examples
1640        ///
1641        /// ```
1642        /// # use std::num::NonZero;
1643        /// #
1644        #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::MIN.get(), 1", stringify!($Int), ");")]
1645        /// ```
1646        #[stable(feature = "nonzero_min_max", since = "1.70.0")]
1647        pub const MIN: Self = Self::new(1).unwrap();
1648
1649        /// The largest value that can be represented by this non-zero
1650        /// integer type,
1651        #[doc = concat!("equal to [`", stringify!($Int), "::MAX`].")]
1652        ///
1653        /// # Examples
1654        ///
1655        /// ```
1656        /// # use std::num::NonZero;
1657        /// #
1658        #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::MAX.get(), ", stringify!($Int), "::MAX);")]
1659        /// ```
1660        #[stable(feature = "nonzero_min_max", since = "1.70.0")]
1661        pub const MAX: Self = Self::new(<$Int>::MAX).unwrap();
1662
1663        /// Adds an unsigned integer to a non-zero value.
1664        /// Checks for overflow and returns [`None`] on overflow.
1665        /// As a consequence, the result cannot wrap to zero.
1666        ///
1667        ///
1668        /// # Examples
1669        ///
1670        /// ```
1671        /// # use std::num::NonZero;
1672        /// #
1673        /// # fn main() { test().unwrap(); }
1674        /// # fn test() -> Option<()> {
1675        #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ")?;")]
1676        #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1677        #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1678        ///
1679        /// assert_eq!(Some(two), one.checked_add(1));
1680        /// assert_eq!(None, max.checked_add(1));
1681        /// # Some(())
1682        /// # }
1683        /// ```
1684        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1685        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1686        #[must_use = "this returns the result of the operation, \
1687                      without modifying the original"]
1688        #[inline]
1689        pub const fn checked_add(self, other: $Int) -> Option<Self> {
1690            if let Some(result) = self.get().checked_add(other) {
1691                // SAFETY:
1692                // - `checked_add` returns `None` on overflow
1693                // - `self` is non-zero
1694                // - the only way to get zero from an addition without overflow is for both
1695                //   sides to be zero
1696                //
1697                // So the result cannot be zero.
1698                Some(unsafe { Self::new_unchecked(result) })
1699            } else {
1700                None
1701            }
1702        }
1703
1704        /// Adds an unsigned integer to a non-zero value.
1705        #[doc = concat!("Return [`NonZero::<", stringify!($Int), ">::MAX`] on overflow.")]
1706        ///
1707        /// # Examples
1708        ///
1709        /// ```
1710        /// # use std::num::NonZero;
1711        /// #
1712        /// # fn main() { test().unwrap(); }
1713        /// # fn test() -> Option<()> {
1714        #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ")?;")]
1715        #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1716        #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1717        ///
1718        /// assert_eq!(two, one.saturating_add(1));
1719        /// assert_eq!(max, max.saturating_add(1));
1720        /// # Some(())
1721        /// # }
1722        /// ```
1723        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1724        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1725        #[must_use = "this returns the result of the operation, \
1726                      without modifying the original"]
1727        #[inline]
1728        pub const fn saturating_add(self, other: $Int) -> Self {
1729            // SAFETY:
1730            // - `saturating_add` returns `u*::MAX` on overflow, which is non-zero
1731            // - `self` is non-zero
1732            // - the only way to get zero from an addition without overflow is for both
1733            //   sides to be zero
1734            //
1735            // So the result cannot be zero.
1736            unsafe { Self::new_unchecked(self.get().saturating_add(other)) }
1737        }
1738
1739        /// Adds an unsigned integer to a non-zero value,
1740        /// assuming overflow cannot occur.
1741        /// Overflow is unchecked, and it is undefined behavior to overflow
1742        /// *even if the result would wrap to a non-zero value*.
1743        ///
1744        /// # Safety
1745        ///
1746        /// This results in undefined behavior when
1747        #[doc = concat!("`self + rhs > ", stringify!($Int), "::MAX`.")]
1748        ///
1749        /// # Examples
1750        ///
1751        /// ```
1752        /// #![feature(nonzero_ops)]
1753        ///
1754        /// # use std::num::NonZero;
1755        /// #
1756        /// # fn main() { test().unwrap(); }
1757        /// # fn test() -> Option<()> {
1758        #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ")?;")]
1759        #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1760        ///
1761        /// assert_eq!(two, unsafe { one.unchecked_add(1) });
1762        /// # Some(())
1763        /// # }
1764        /// ```
1765        #[unstable(feature = "nonzero_ops", issue = "84186")]
1766        #[must_use = "this returns the result of the operation, \
1767                      without modifying the original"]
1768        #[inline]
1769        pub const unsafe fn unchecked_add(self, other: $Int) -> Self {
1770            // SAFETY: The caller ensures there is no overflow.
1771            unsafe { Self::new_unchecked(self.get().unchecked_add(other)) }
1772        }
1773
1774        /// Returns the smallest power of two greater than or equal to `self`.
1775        /// Checks for overflow and returns [`None`]
1776        /// if the next power of two is greater than the type’s maximum value.
1777        /// As a consequence, the result cannot wrap to zero.
1778        ///
1779        /// # Examples
1780        ///
1781        /// ```
1782        /// # use std::num::NonZero;
1783        /// #
1784        /// # fn main() { test().unwrap(); }
1785        /// # fn test() -> Option<()> {
1786        #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1787        #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ")?;")]
1788        #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1789        #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1790        ///
1791        /// assert_eq!(Some(two), two.checked_next_power_of_two() );
1792        /// assert_eq!(Some(four), three.checked_next_power_of_two() );
1793        /// assert_eq!(None, max.checked_next_power_of_two() );
1794        /// # Some(())
1795        /// # }
1796        /// ```
1797        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1798        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1799        #[must_use = "this returns the result of the operation, \
1800                      without modifying the original"]
1801        #[inline]
1802        pub const fn checked_next_power_of_two(self) -> Option<Self> {
1803            if let Some(nz) = self.get().checked_next_power_of_two() {
1804                // SAFETY: The next power of two is positive
1805                // and overflow is checked.
1806                Some(unsafe { Self::new_unchecked(nz) })
1807            } else {
1808                None
1809            }
1810        }
1811
1812        /// Returns the base 2 logarithm of the number, rounded down.
1813        ///
1814        /// This is the same operation as
1815        #[doc = concat!("[`", stringify!($Int), "::ilog2`],")]
1816        /// except that it has no failure cases to worry about
1817        /// since this value can never be zero.
1818        ///
1819        /// Note that this is equivalent to [`highest_one`](Self::highest_one).
1820        ///
1821        /// # Examples
1822        ///
1823        /// ```
1824        /// # use std::num::NonZero;
1825        /// #
1826        /// # fn main() { test().unwrap(); }
1827        /// # fn test() -> Option<()> {
1828        #[doc = concat!("assert_eq!(NonZero::new(7", stringify!($Int), ")?.ilog2(), 2);")]
1829        #[doc = concat!("assert_eq!(NonZero::new(8", stringify!($Int), ")?.ilog2(), 3);")]
1830        #[doc = concat!("assert_eq!(NonZero::new(9", stringify!($Int), ")?.ilog2(), 3);")]
1831        /// # Some(())
1832        /// # }
1833        /// ```
1834        #[stable(feature = "int_log", since = "1.67.0")]
1835        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1836        #[must_use = "this returns the result of the operation, \
1837                      without modifying the original"]
1838        #[inline]
1839        pub const fn ilog2(self) -> u32 {
1840            Self::BITS - 1 - self.leading_zeros()
1841        }
1842
1843        /// Returns the base 10 logarithm of the number, rounded down.
1844        ///
1845        /// This is the same operation as
1846        #[doc = concat!("[`", stringify!($Int), "::ilog10`],")]
1847        /// except that it has no failure cases to worry about
1848        /// since this value can never be zero.
1849        ///
1850        /// # Examples
1851        ///
1852        /// ```
1853        /// # use std::num::NonZero;
1854        /// #
1855        /// # fn main() { test().unwrap(); }
1856        /// # fn test() -> Option<()> {
1857        #[doc = concat!("assert_eq!(NonZero::new(99", stringify!($Int), ")?.ilog10(), 1);")]
1858        #[doc = concat!("assert_eq!(NonZero::new(100", stringify!($Int), ")?.ilog10(), 2);")]
1859        #[doc = concat!("assert_eq!(NonZero::new(101", stringify!($Int), ")?.ilog10(), 2);")]
1860        /// # Some(())
1861        /// # }
1862        /// ```
1863        #[stable(feature = "int_log", since = "1.67.0")]
1864        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1865        #[must_use = "this returns the result of the operation, \
1866                      without modifying the original"]
1867        #[inline]
1868        pub const fn ilog10(self) -> u32 {
1869            imp::int_log10::$Int(self)
1870        }
1871
1872        /// Calculates the midpoint (average) between `self` and `rhs`.
1873        ///
1874        /// `midpoint(a, b)` is `(a + b) >> 1` as if it were performed in a
1875        /// sufficiently-large signed integral type. This implies that the result is
1876        /// always rounded towards negative infinity and that no overflow will ever occur.
1877        ///
1878        /// # Examples
1879        ///
1880        /// ```
1881        /// # use std::num::NonZero;
1882        /// #
1883        /// # fn main() { test().unwrap(); }
1884        /// # fn test() -> Option<()> {
1885        #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ")?;")]
1886        #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1887        #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1888        ///
1889        /// assert_eq!(one.midpoint(four), two);
1890        /// assert_eq!(four.midpoint(one), two);
1891        /// # Some(())
1892        /// # }
1893        /// ```
1894        #[stable(feature = "num_midpoint", since = "1.85.0")]
1895        #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
1896        #[must_use = "this returns the result of the operation, \
1897                      without modifying the original"]
1898        #[doc(alias = "average_floor")]
1899        #[doc(alias = "average")]
1900        #[inline]
1901        pub const fn midpoint(self, rhs: Self) -> Self {
1902            // SAFETY: The only way to get `0` with midpoint is to have two opposite or
1903            // near opposite numbers: (-5, 5), (0, 1), (0, 0) which is impossible because
1904            // of the unsignedness of this number and also because `Self` is guaranteed to
1905            // never being 0.
1906            unsafe { Self::new_unchecked(self.get().midpoint(rhs.get())) }
1907        }
1908
1909        /// Returns `true` if and only if `self == (1 << k)` for some `k`.
1910        ///
1911        /// On many architectures, this function can perform better than `is_power_of_two()`
1912        /// on the underlying integer type, as special handling of zero can be avoided.
1913        ///
1914        /// # Examples
1915        ///
1916        /// ```
1917        /// # use std::num::NonZero;
1918        /// #
1919        /// # fn main() { test().unwrap(); }
1920        /// # fn test() -> Option<()> {
1921        #[doc = concat!("let eight = NonZero::new(8", stringify!($Int), ")?;")]
1922        /// assert!(eight.is_power_of_two());
1923        #[doc = concat!("let ten = NonZero::new(10", stringify!($Int), ")?;")]
1924        /// assert!(!ten.is_power_of_two());
1925        /// # Some(())
1926        /// # }
1927        /// ```
1928        #[must_use]
1929        #[stable(feature = "nonzero_is_power_of_two", since = "1.59.0")]
1930        #[rustc_const_stable(feature = "nonzero_is_power_of_two", since = "1.59.0")]
1931        #[inline]
1932        pub const fn is_power_of_two(self) -> bool {
1933            // LLVM 11 normalizes `unchecked_sub(x, 1) & x == 0` to the implementation seen here.
1934            // On the basic x86-64 target, this saves 3 instructions for the zero check.
1935            // On x86_64 with BMI1, being nonzero lets it codegen to `BLSR`, which saves an instruction
1936            // compared to the `POPCNT` implementation on the underlying integer type.
1937
1938            intrinsics::ctpop(self.get()) < 2
1939        }
1940
1941        /// Returns the square root of the number, rounded down.
1942        ///
1943        /// # Examples
1944        ///
1945        /// ```
1946        /// # use std::num::NonZero;
1947        /// #
1948        /// # fn main() { test().unwrap(); }
1949        /// # fn test() -> Option<()> {
1950        #[doc = concat!("let ten = NonZero::new(10", stringify!($Int), ")?;")]
1951        #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ")?;")]
1952        ///
1953        /// assert_eq!(ten.isqrt(), three);
1954        /// # Some(())
1955        /// # }
1956        /// ```
1957        #[stable(feature = "isqrt", since = "1.84.0")]
1958        #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
1959        #[must_use = "this returns the result of the operation, \
1960                      without modifying the original"]
1961        #[inline]
1962        pub const fn isqrt(self) -> Self {
1963            let result = self.get().isqrt();
1964
1965            // SAFETY: Integer square root is a monotonically nondecreasing
1966            // function, which means that increasing the input will never cause
1967            // the output to decrease. Thus, since the input for nonzero
1968            // unsigned integers has a lower bound of 1, the lower bound of the
1969            // results will be sqrt(1), which is 1, so a result can't be zero.
1970            unsafe { Self::new_unchecked(result) }
1971        }
1972
1973        /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
1974        ///
1975        /// # Examples
1976        ///
1977        /// ```
1978        /// # use std::num::NonZero;
1979        ///
1980        #[doc = concat!("let n = NonZero::<", stringify!($Int), ">::MAX;")]
1981        ///
1982        #[doc = concat!("assert_eq!(n.cast_signed(), NonZero::new(-1", stringify!($Sint), ").unwrap());")]
1983        /// ```
1984        #[stable(feature = "integer_sign_cast", since = "1.87.0")]
1985        #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
1986        #[must_use = "this returns the result of the operation, \
1987                      without modifying the original"]
1988        #[inline(always)]
1989        pub const fn cast_signed(self) -> NonZero<$Sint> {
1990            // SAFETY: `self.get()` can't be zero
1991            unsafe { NonZero::new_unchecked(self.get().cast_signed()) }
1992        }
1993
1994        /// Returns the minimum number of bits required to represent `self`.
1995        ///
1996        /// # Examples
1997        ///
1998        /// ```
1999        /// # use core::num::NonZero;
2000        /// #
2001        /// # fn main() { test().unwrap(); }
2002        /// # fn test() -> Option<()> {
2003        #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1)?.bit_width(), NonZero::new(1)?);")]
2004        #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b111)?.bit_width(), NonZero::new(3)?);")]
2005        #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1110)?.bit_width(), NonZero::new(4)?);")]
2006        /// # Some(())
2007        /// # }
2008        /// ```
2009        #[stable(feature = "uint_bit_width", since = "1.97.0")]
2010        #[rustc_const_stable(feature = "uint_bit_width", since = "1.97.0")]
2011        #[must_use = "this returns the result of the operation, \
2012                      without modifying the original"]
2013        #[inline(always)]
2014        pub const fn bit_width(self) -> NonZero<u32> {
2015            // SAFETY: Since `self.leading_zeros()` is always less than
2016            // `Self::BITS`, this subtraction can never be zero.
2017            unsafe { NonZero::new_unchecked(Self::BITS - self.leading_zeros()) }
2018        }
2019    };
2020
2021    // Associated items for signed nonzero types only.
2022    (
2023        Primitive = signed $Int:ident,
2024        SignedPrimitive = $Sint:ty,
2025        UnsignedPrimitive = $Uint:ty,
2026    ) => {
2027        /// The smallest value that can be represented by this non-zero
2028        /// integer type,
2029        #[doc = concat!("equal to [`", stringify!($Int), "::MIN`].")]
2030        ///
2031        /// Note: While most integer types are defined for every whole
2032        /// number between `MIN` and `MAX`, signed non-zero integers are
2033        /// a special case. They have a "gap" at 0.
2034        ///
2035        /// # Examples
2036        ///
2037        /// ```
2038        /// # use std::num::NonZero;
2039        /// #
2040        #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::MIN.get(), ", stringify!($Int), "::MIN);")]
2041        /// ```
2042        #[stable(feature = "nonzero_min_max", since = "1.70.0")]
2043        pub const MIN: Self = Self::new(<$Int>::MIN).unwrap();
2044
2045        /// The largest value that can be represented by this non-zero
2046        /// integer type,
2047        #[doc = concat!("equal to [`", stringify!($Int), "::MAX`].")]
2048        ///
2049        /// Note: While most integer types are defined for every whole
2050        /// number between `MIN` and `MAX`, signed non-zero integers are
2051        /// a special case. They have a "gap" at 0.
2052        ///
2053        /// # Examples
2054        ///
2055        /// ```
2056        /// # use std::num::NonZero;
2057        /// #
2058        #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::MAX.get(), ", stringify!($Int), "::MAX);")]
2059        /// ```
2060        #[stable(feature = "nonzero_min_max", since = "1.70.0")]
2061        pub const MAX: Self = Self::new(<$Int>::MAX).unwrap();
2062
2063        /// Computes the absolute value of self.
2064        #[doc = concat!("See [`", stringify!($Int), "::abs`]")]
2065        /// for documentation on overflow behavior.
2066        ///
2067        /// # Example
2068        ///
2069        /// ```
2070        /// # use std::num::NonZero;
2071        /// #
2072        /// # fn main() { test().unwrap(); }
2073        /// # fn test() -> Option<()> {
2074        #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2075        #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2076        ///
2077        /// assert_eq!(pos, pos.abs());
2078        /// assert_eq!(pos, neg.abs());
2079        /// # Some(())
2080        /// # }
2081        /// ```
2082        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2083        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2084        #[must_use = "this returns the result of the operation, \
2085                      without modifying the original"]
2086        #[inline]
2087        pub const fn abs(self) -> Self {
2088            // SAFETY: This cannot overflow to zero.
2089            unsafe { Self::new_unchecked(self.get().abs()) }
2090        }
2091
2092        /// Checked absolute value.
2093        /// Checks for overflow and returns [`None`] if
2094        #[doc = concat!("`self == NonZero::<", stringify!($Int), ">::MIN`.")]
2095        /// The result cannot be zero.
2096        ///
2097        /// # Example
2098        ///
2099        /// ```
2100        /// # use std::num::NonZero;
2101        /// #
2102        /// # fn main() { test().unwrap(); }
2103        /// # fn test() -> Option<()> {
2104        #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2105        #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2106        #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2107        ///
2108        /// assert_eq!(Some(pos), neg.checked_abs());
2109        /// assert_eq!(None, min.checked_abs());
2110        /// # Some(())
2111        /// # }
2112        /// ```
2113        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2114        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2115        #[must_use = "this returns the result of the operation, \
2116                      without modifying the original"]
2117        #[inline]
2118        pub const fn checked_abs(self) -> Option<Self> {
2119            if let Some(nz) = self.get().checked_abs() {
2120                // SAFETY: absolute value of nonzero cannot yield zero values.
2121                Some(unsafe { Self::new_unchecked(nz) })
2122            } else {
2123                None
2124            }
2125        }
2126
2127        /// Computes the absolute value of self,
2128        /// with overflow information, see
2129        #[doc = concat!("[`", stringify!($Int), "::overflowing_abs`].")]
2130        ///
2131        /// # Example
2132        ///
2133        /// ```
2134        /// # use std::num::NonZero;
2135        /// #
2136        /// # fn main() { test().unwrap(); }
2137        /// # fn test() -> Option<()> {
2138        #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2139        #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2140        #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2141        ///
2142        /// assert_eq!((pos, false), pos.overflowing_abs());
2143        /// assert_eq!((pos, false), neg.overflowing_abs());
2144        /// assert_eq!((min, true), min.overflowing_abs());
2145        /// # Some(())
2146        /// # }
2147        /// ```
2148        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2149        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2150        #[must_use = "this returns the result of the operation, \
2151                      without modifying the original"]
2152        #[inline]
2153        pub const fn overflowing_abs(self) -> (Self, bool) {
2154            let (nz, flag) = self.get().overflowing_abs();
2155            (
2156                // SAFETY: absolute value of nonzero cannot yield zero values.
2157                unsafe { Self::new_unchecked(nz) },
2158                flag,
2159            )
2160        }
2161
2162        /// Saturating absolute value, see
2163        #[doc = concat!("[`", stringify!($Int), "::saturating_abs`].")]
2164        ///
2165        /// # Example
2166        ///
2167        /// ```
2168        /// # use std::num::NonZero;
2169        /// #
2170        /// # fn main() { test().unwrap(); }
2171        /// # fn test() -> Option<()> {
2172        #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2173        #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2174        #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2175        #[doc = concat!("let min_plus = NonZero::new(", stringify!($Int), "::MIN + 1)?;")]
2176        #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
2177        ///
2178        /// assert_eq!(pos, pos.saturating_abs());
2179        /// assert_eq!(pos, neg.saturating_abs());
2180        /// assert_eq!(max, min.saturating_abs());
2181        /// assert_eq!(max, min_plus.saturating_abs());
2182        /// # Some(())
2183        /// # }
2184        /// ```
2185        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2186        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2187        #[must_use = "this returns the result of the operation, \
2188                      without modifying the original"]
2189        #[inline]
2190        pub const fn saturating_abs(self) -> Self {
2191            // SAFETY: absolute value of nonzero cannot yield zero values.
2192            unsafe { Self::new_unchecked(self.get().saturating_abs()) }
2193        }
2194
2195        /// Wrapping absolute value, see
2196        #[doc = concat!("[`", stringify!($Int), "::wrapping_abs`].")]
2197        ///
2198        /// # Example
2199        ///
2200        /// ```
2201        /// # use std::num::NonZero;
2202        /// #
2203        /// # fn main() { test().unwrap(); }
2204        /// # fn test() -> Option<()> {
2205        #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2206        #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2207        #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2208        #[doc = concat!("# let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
2209        ///
2210        /// assert_eq!(pos, pos.wrapping_abs());
2211        /// assert_eq!(pos, neg.wrapping_abs());
2212        /// assert_eq!(min, min.wrapping_abs());
2213        /// assert_eq!(max, (-max).wrapping_abs());
2214        /// # Some(())
2215        /// # }
2216        /// ```
2217        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2218        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2219        #[must_use = "this returns the result of the operation, \
2220                      without modifying the original"]
2221        #[inline]
2222        pub const fn wrapping_abs(self) -> Self {
2223            // SAFETY: absolute value of nonzero cannot yield zero values.
2224            unsafe { Self::new_unchecked(self.get().wrapping_abs()) }
2225        }
2226
2227        /// Computes the absolute value of self
2228        /// without any wrapping or panicking.
2229        ///
2230        /// # Example
2231        ///
2232        /// ```
2233        /// # use std::num::NonZero;
2234        /// #
2235        /// # fn main() { test().unwrap(); }
2236        /// # fn test() -> Option<()> {
2237        #[doc = concat!("let u_pos = NonZero::new(1", stringify!($Uint), ")?;")]
2238        #[doc = concat!("let i_pos = NonZero::new(1", stringify!($Int), ")?;")]
2239        #[doc = concat!("let i_neg = NonZero::new(-1", stringify!($Int), ")?;")]
2240        #[doc = concat!("let i_min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2241        #[doc = concat!("let u_max = NonZero::new(", stringify!($Uint), "::MAX / 2 + 1)?;")]
2242        ///
2243        /// assert_eq!(u_pos, i_pos.unsigned_abs());
2244        /// assert_eq!(u_pos, i_neg.unsigned_abs());
2245        /// assert_eq!(u_max, i_min.unsigned_abs());
2246        /// # Some(())
2247        /// # }
2248        /// ```
2249        #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2250        #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2251        #[must_use = "this returns the result of the operation, \
2252                      without modifying the original"]
2253        #[inline]
2254        pub const fn unsigned_abs(self) -> NonZero<$Uint> {
2255            // SAFETY: absolute value of nonzero cannot yield zero values.
2256            unsafe { NonZero::new_unchecked(self.get().unsigned_abs()) }
2257        }
2258
2259        /// Returns `true` if `self` is positive and `false` if the
2260        /// number is negative.
2261        ///
2262        /// # Example
2263        ///
2264        /// ```
2265        /// # use std::num::NonZero;
2266        /// #
2267        /// # fn main() { test().unwrap(); }
2268        /// # fn test() -> Option<()> {
2269        #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2270        #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2271        ///
2272        /// assert!(pos_five.is_positive());
2273        /// assert!(!neg_five.is_positive());
2274        /// # Some(())
2275        /// # }
2276        /// ```
2277        #[must_use]
2278        #[inline]
2279        #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2280        #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2281        pub const fn is_positive(self) -> bool {
2282            self.get().is_positive()
2283        }
2284
2285        /// Returns `true` if `self` is negative and `false` if the
2286        /// number is positive.
2287        ///
2288        /// # Example
2289        ///
2290        /// ```
2291        /// # use std::num::NonZero;
2292        /// #
2293        /// # fn main() { test().unwrap(); }
2294        /// # fn test() -> Option<()> {
2295        #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2296        #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2297        ///
2298        /// assert!(neg_five.is_negative());
2299        /// assert!(!pos_five.is_negative());
2300        /// # Some(())
2301        /// # }
2302        /// ```
2303        #[must_use]
2304        #[inline]
2305        #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2306        #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2307        pub const fn is_negative(self) -> bool {
2308            self.get().is_negative()
2309        }
2310
2311        /// Checked negation. Computes `-self`,
2312        #[doc = concat!("returning `None` if `self == NonZero::<", stringify!($Int), ">::MIN`.")]
2313        ///
2314        /// # Example
2315        ///
2316        /// ```
2317        /// # use std::num::NonZero;
2318        /// #
2319        /// # fn main() { test().unwrap(); }
2320        /// # fn test() -> Option<()> {
2321        #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2322        #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2323        #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2324        ///
2325        /// assert_eq!(pos_five.checked_neg(), Some(neg_five));
2326        /// assert_eq!(min.checked_neg(), None);
2327        /// # Some(())
2328        /// # }
2329        /// ```
2330        #[inline]
2331        #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2332        #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2333        pub const fn checked_neg(self) -> Option<Self> {
2334            if let Some(result) = self.get().checked_neg() {
2335                // SAFETY: negation of nonzero cannot yield zero values.
2336                return Some(unsafe { Self::new_unchecked(result) });
2337            }
2338            None
2339        }
2340
2341        /// Negates self, overflowing if this is equal to the minimum value.
2342        ///
2343        #[doc = concat!("See [`", stringify!($Int), "::overflowing_neg`]")]
2344        /// for documentation on overflow behavior.
2345        ///
2346        /// # Example
2347        ///
2348        /// ```
2349        /// # use std::num::NonZero;
2350        /// #
2351        /// # fn main() { test().unwrap(); }
2352        /// # fn test() -> Option<()> {
2353        #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2354        #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2355        #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2356        ///
2357        /// assert_eq!(pos_five.overflowing_neg(), (neg_five, false));
2358        /// assert_eq!(min.overflowing_neg(), (min, true));
2359        /// # Some(())
2360        /// # }
2361        /// ```
2362        #[inline]
2363        #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2364        #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2365        pub const fn overflowing_neg(self) -> (Self, bool) {
2366            let (result, overflow) = self.get().overflowing_neg();
2367            // SAFETY: negation of nonzero cannot yield zero values.
2368            ((unsafe { Self::new_unchecked(result) }), overflow)
2369        }
2370
2371        /// Saturating negation. Computes `-self`,
2372        #[doc = concat!("returning [`NonZero::<", stringify!($Int), ">::MAX`]")]
2373        #[doc = concat!("if `self == NonZero::<", stringify!($Int), ">::MIN`")]
2374        /// instead of overflowing.
2375        ///
2376        /// # Example
2377        ///
2378        /// ```
2379        /// # use std::num::NonZero;
2380        /// #
2381        /// # fn main() { test().unwrap(); }
2382        /// # fn test() -> Option<()> {
2383        #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2384        #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2385        #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2386        #[doc = concat!("let min_plus_one = NonZero::new(", stringify!($Int), "::MIN + 1)?;")]
2387        #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
2388        ///
2389        /// assert_eq!(pos_five.saturating_neg(), neg_five);
2390        /// assert_eq!(min.saturating_neg(), max);
2391        /// assert_eq!(max.saturating_neg(), min_plus_one);
2392        /// # Some(())
2393        /// # }
2394        /// ```
2395        #[inline]
2396        #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2397        #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2398        pub const fn saturating_neg(self) -> Self {
2399            if let Some(result) = self.checked_neg() {
2400                return result;
2401            }
2402            Self::MAX
2403        }
2404
2405        /// Wrapping (modular) negation. Computes `-self`, wrapping around at the boundary
2406        /// of the type.
2407        ///
2408        #[doc = concat!("See [`", stringify!($Int), "::wrapping_neg`]")]
2409        /// for documentation on overflow behavior.
2410        ///
2411        /// # Example
2412        ///
2413        /// ```
2414        /// # use std::num::NonZero;
2415        /// #
2416        /// # fn main() { test().unwrap(); }
2417        /// # fn test() -> Option<()> {
2418        #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2419        #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2420        #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2421        ///
2422        /// assert_eq!(pos_five.wrapping_neg(), neg_five);
2423        /// assert_eq!(min.wrapping_neg(), min);
2424        /// # Some(())
2425        /// # }
2426        /// ```
2427        #[inline]
2428        #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2429        #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2430        pub const fn wrapping_neg(self) -> Self {
2431            let result = self.get().wrapping_neg();
2432            // SAFETY: negation of nonzero cannot yield zero values.
2433            unsafe { Self::new_unchecked(result) }
2434        }
2435
2436        /// Returns the bit pattern of `self` reinterpreted as an unsigned integer of the same size.
2437        ///
2438        /// # Examples
2439        ///
2440        /// ```
2441        /// # use std::num::NonZero;
2442        ///
2443        #[doc = concat!("let n = NonZero::new(-1", stringify!($Int), ").unwrap();")]
2444        ///
2445        #[doc = concat!("assert_eq!(n.cast_unsigned(), NonZero::<", stringify!($Uint), ">::MAX);")]
2446        /// ```
2447        #[stable(feature = "integer_sign_cast", since = "1.87.0")]
2448        #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
2449        #[must_use = "this returns the result of the operation, \
2450                      without modifying the original"]
2451        #[inline(always)]
2452        pub const fn cast_unsigned(self) -> NonZero<$Uint> {
2453            // SAFETY: `self.get()` can't be zero
2454            unsafe { NonZero::new_unchecked(self.get().cast_unsigned()) }
2455        }
2456
2457    };
2458}
2459
2460nonzero_integer! {
2461    Self = NonZeroU8,
2462    Primitive = unsigned u8,
2463    SignedPrimitive = i8,
2464    rot = 2,
2465    rot_op = "0x82",
2466    rot_result = "0xa",
2467    swap_op = "0x12",
2468    swapped = "0x12",
2469    reversed = "0x48",
2470}
2471
2472nonzero_integer! {
2473    Self = NonZeroU16,
2474    Primitive = unsigned u16,
2475    SignedPrimitive = i16,
2476    rot = 4,
2477    rot_op = "0xa003",
2478    rot_result = "0x3a",
2479    swap_op = "0x1234",
2480    swapped = "0x3412",
2481    reversed = "0x2c48",
2482}
2483
2484nonzero_integer! {
2485    Self = NonZeroU32,
2486    Primitive = unsigned u32,
2487    SignedPrimitive = i32,
2488    rot = 8,
2489    rot_op = "0x10000b3",
2490    rot_result = "0xb301",
2491    swap_op = "0x12345678",
2492    swapped = "0x78563412",
2493    reversed = "0x1e6a2c48",
2494}
2495
2496nonzero_integer! {
2497    Self = NonZeroU64,
2498    Primitive = unsigned u64,
2499    SignedPrimitive = i64,
2500    rot = 12,
2501    rot_op = "0xaa00000000006e1",
2502    rot_result = "0x6e10aa",
2503    swap_op = "0x1234567890123456",
2504    swapped = "0x5634129078563412",
2505    reversed = "0x6a2c48091e6a2c48",
2506}
2507
2508nonzero_integer! {
2509    Self = NonZeroU128,
2510    Primitive = unsigned u128,
2511    SignedPrimitive = i128,
2512    rot = 16,
2513    rot_op = "0x13f40000000000000000000000004f76",
2514    rot_result = "0x4f7613f4",
2515    swap_op = "0x12345678901234567890123456789012",
2516    swapped = "0x12907856341290785634129078563412",
2517    reversed = "0x48091e6a2c48091e6a2c48091e6a2c48",
2518}
2519
2520#[cfg(target_pointer_width = "16")]
2521nonzero_integer! {
2522    Self = NonZeroUsize,
2523    Primitive = unsigned usize,
2524    SignedPrimitive = isize,
2525    rot = 4,
2526    rot_op = "0xa003",
2527    rot_result = "0x3a",
2528    swap_op = "0x1234",
2529    swapped = "0x3412",
2530    reversed = "0x2c48",
2531}
2532
2533#[cfg(target_pointer_width = "32")]
2534nonzero_integer! {
2535    Self = NonZeroUsize,
2536    Primitive = unsigned usize,
2537    SignedPrimitive = isize,
2538    rot = 8,
2539    rot_op = "0x10000b3",
2540    rot_result = "0xb301",
2541    swap_op = "0x12345678",
2542    swapped = "0x78563412",
2543    reversed = "0x1e6a2c48",
2544}
2545
2546#[cfg(target_pointer_width = "64")]
2547nonzero_integer! {
2548    Self = NonZeroUsize,
2549    Primitive = unsigned usize,
2550    SignedPrimitive = isize,
2551    rot = 12,
2552    rot_op = "0xaa00000000006e1",
2553    rot_result = "0x6e10aa",
2554    swap_op = "0x1234567890123456",
2555    swapped = "0x5634129078563412",
2556    reversed = "0x6a2c48091e6a2c48",
2557}
2558
2559nonzero_integer! {
2560    Self = NonZeroI8,
2561    Primitive = signed i8,
2562    UnsignedPrimitive = u8,
2563    rot = 2,
2564    rot_op = "-0x7e",
2565    rot_result = "0xa",
2566    swap_op = "0x12",
2567    swapped = "0x12",
2568    reversed = "0x48",
2569}
2570
2571nonzero_integer! {
2572    Self = NonZeroI16,
2573    Primitive = signed i16,
2574    UnsignedPrimitive = u16,
2575    rot = 4,
2576    rot_op = "-0x5ffd",
2577    rot_result = "0x3a",
2578    swap_op = "0x1234",
2579    swapped = "0x3412",
2580    reversed = "0x2c48",
2581}
2582
2583nonzero_integer! {
2584    Self = NonZeroI32,
2585    Primitive = signed i32,
2586    UnsignedPrimitive = u32,
2587    rot = 8,
2588    rot_op = "0x10000b3",
2589    rot_result = "0xb301",
2590    swap_op = "0x12345678",
2591    swapped = "0x78563412",
2592    reversed = "0x1e6a2c48",
2593}
2594
2595nonzero_integer! {
2596    Self = NonZeroI64,
2597    Primitive = signed i64,
2598    UnsignedPrimitive = u64,
2599    rot = 12,
2600    rot_op = "0xaa00000000006e1",
2601    rot_result = "0x6e10aa",
2602    swap_op = "0x1234567890123456",
2603    swapped = "0x5634129078563412",
2604    reversed = "0x6a2c48091e6a2c48",
2605}
2606
2607nonzero_integer! {
2608    Self = NonZeroI128,
2609    Primitive = signed i128,
2610    UnsignedPrimitive = u128,
2611    rot = 16,
2612    rot_op = "0x13f40000000000000000000000004f76",
2613    rot_result = "0x4f7613f4",
2614    swap_op = "0x12345678901234567890123456789012",
2615    swapped = "0x12907856341290785634129078563412",
2616    reversed = "0x48091e6a2c48091e6a2c48091e6a2c48",
2617}
2618
2619#[cfg(target_pointer_width = "16")]
2620nonzero_integer! {
2621    Self = NonZeroIsize,
2622    Primitive = signed isize,
2623    UnsignedPrimitive = usize,
2624    rot = 4,
2625    rot_op = "-0x5ffd",
2626    rot_result = "0x3a",
2627    swap_op = "0x1234",
2628    swapped = "0x3412",
2629    reversed = "0x2c48",
2630}
2631
2632#[cfg(target_pointer_width = "32")]
2633nonzero_integer! {
2634    Self = NonZeroIsize,
2635    Primitive = signed isize,
2636    UnsignedPrimitive = usize,
2637    rot = 8,
2638    rot_op = "0x10000b3",
2639    rot_result = "0xb301",
2640    swap_op = "0x12345678",
2641    swapped = "0x78563412",
2642    reversed = "0x1e6a2c48",
2643}
2644
2645#[cfg(target_pointer_width = "64")]
2646nonzero_integer! {
2647    Self = NonZeroIsize,
2648    Primitive = signed isize,
2649    UnsignedPrimitive = usize,
2650    rot = 12,
2651    rot_op = "0xaa00000000006e1",
2652    rot_result = "0x6e10aa",
2653    swap_op = "0x1234567890123456",
2654    swapped = "0x5634129078563412",
2655    reversed = "0x6a2c48091e6a2c48",
2656}