core/num/nonzero.rs
1//! Definitions of integer that is known not to equal zero.
2
3use super::{IntErrorKind, ParseIntError, TryFromIntError};
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, slice, 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 = "more_from_nonzero", since = "CURRENT_RUSTC_VERSION")]
309impl<'a, T> From<&'a NonZero<T>> for &'a T
310where
311 T: ZeroablePrimitive,
312{
313 #[inline]
314 fn from(nonzero: &'a NonZero<T>) -> &'a T {
315 nonzero.as_ref()
316 }
317}
318
319// FIXME: see library/std/tests/slice-from-array-issue-113238.rs
320/*
321#[stable(feature = "more_from_nonzero", since = "CURRENT_RUSTC_VERSION")]
322impl<'a, T> From<&'a [NonZero<T>]> for &'a [T]
323where
324 T: ZeroablePrimitive,
325{
326 #[inline]
327 fn from(nonzero: &'a [NonZero<T>]) -> &'a [T] {
328 nonzero.as_zeroable()
329 }
330}
331impl<T> [NonZero<T>]
332where
333 T: ZeroablePrimitive,
334{
335 /// Implementation of `From<&[NonZero<T>]> for &[T]`.
336 #[must_use]
337 #[inline]
338 fn as_zeroable(&self) -> &[T] {
339 // SAFETY: `repr(transparent)` ensures that `NonZero<T>` has same layout as `T`, and thus
340 // `[NonZero<T>]` has same layout as `[T]`
341 unsafe { &*(slice::from_raw_parts(self.as_ptr().cast::<T>(), self.len())) }
342 }
343}
344*/
345
346#[stable(feature = "more_from_nonzero", since = "CURRENT_RUSTC_VERSION")]
347impl<T, const N: usize> From<[NonZero<T>; N]> for [T; N]
348where
349 T: ZeroablePrimitive,
350{
351 #[inline]
352 fn from(nonzero: [NonZero<T>; N]) -> [T; N] {
353 nonzero.into_zeroable()
354 }
355}
356
357// FIXME: can't detect that ZeroablePrimitive is a sealed trait
358macro_rules! impl_ref_try_from {
359 ($($t:ty),* $(,)?) => {
360 $(
361 #[stable(feature = "more_from_nonzero", since = "CURRENT_RUSTC_VERSION")]
362 impl<'a> TryFrom<&'a $t> for &'a NonZero<$t> {
363 type Error = TryFromIntError;
364
365 #[inline]
366 fn try_from(zeroable: &'a $t) -> Result<&'a NonZero<$t>, TryFromIntError> {
367 NonZero::from_ref(zeroable).ok_or(TryFromIntError(IntErrorKind::Zero))
368 }
369 }
370 )*
371 }
372}
373
374impl_ref_try_from! {
375 u8,
376 u16,
377 u32,
378 u64,
379 u128,
380 usize,
381 i8,
382 i16,
383 i32,
384 i64,
385 i128,
386 isize,
387 char,
388}
389
390#[stable(feature = "more_from_nonzero", since = "CURRENT_RUSTC_VERSION")]
391impl<'a, T> TryFrom<&'a [T]> for &'a [NonZero<T>]
392where
393 T: ZeroablePrimitive,
394{
395 type Error = TryFromIntError;
396
397 #[inline]
398 fn try_from(zeroable: &'a [T]) -> Result<&'a [NonZero<T>], TryFromIntError> {
399 NonZero::from_slice(zeroable).ok_or(TryFromIntError(IntErrorKind::Zero))
400 }
401}
402
403#[stable(feature = "more_from_nonzero", since = "CURRENT_RUSTC_VERSION")]
404impl<T, const N: usize> TryFrom<[T; N]> for [NonZero<T>; N]
405where
406 T: ZeroablePrimitive,
407{
408 type Error = TryFromIntError;
409
410 #[inline]
411 fn try_from(zeroable: [T; N]) -> Result<[NonZero<T>; N], TryFromIntError> {
412 NonZero::from_array(zeroable).ok_or(TryFromIntError(IntErrorKind::Zero))
413 }
414}
415
416#[stable(feature = "nonzero_bitor", since = "1.45.0")]
417#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
418const impl<T> BitOr for NonZero<T>
419where
420 T: ZeroablePrimitive + [const] BitOr<Output = T>,
421{
422 type Output = Self;
423
424 #[inline]
425 fn bitor(self, rhs: Self) -> Self::Output {
426 // SAFETY: Bitwise OR of two non-zero values is still non-zero.
427 unsafe { Self::new_unchecked(self.get() | rhs.get()) }
428 }
429}
430
431#[stable(feature = "nonzero_bitor", since = "1.45.0")]
432#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
433const impl<T> BitOr<T> for NonZero<T>
434where
435 T: ZeroablePrimitive + [const] BitOr<Output = T>,
436{
437 type Output = Self;
438
439 #[inline]
440 fn bitor(self, rhs: T) -> Self::Output {
441 // SAFETY: Bitwise OR of a non-zero value with anything is still non-zero.
442 unsafe { Self::new_unchecked(self.get() | rhs) }
443 }
444}
445
446#[stable(feature = "nonzero_bitor", since = "1.45.0")]
447#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
448const impl<T> BitOr<NonZero<T>> for T
449where
450 T: ZeroablePrimitive + [const] BitOr<Output = T>,
451{
452 type Output = NonZero<T>;
453
454 #[inline]
455 fn bitor(self, rhs: NonZero<T>) -> Self::Output {
456 // SAFETY: Bitwise OR of anything with a non-zero value is still non-zero.
457 unsafe { NonZero::new_unchecked(self | rhs.get()) }
458 }
459}
460
461#[stable(feature = "nonzero_bitor", since = "1.45.0")]
462#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
463const impl<T> BitOrAssign for NonZero<T>
464where
465 T: ZeroablePrimitive,
466 Self: [const] BitOr<Output = Self>,
467{
468 #[inline]
469 fn bitor_assign(&mut self, rhs: Self) {
470 *self = *self | rhs;
471 }
472}
473
474#[stable(feature = "nonzero_bitor", since = "1.45.0")]
475#[rustc_const_unstable(feature = "const_ops", issue = "143802")]
476const impl<T> BitOrAssign<T> for NonZero<T>
477where
478 T: ZeroablePrimitive,
479 Self: [const] BitOr<T, Output = Self>,
480{
481 #[inline]
482 fn bitor_assign(&mut self, rhs: T) {
483 *self = *self | rhs;
484 }
485}
486
487impl<T> NonZero<T>
488where
489 T: ZeroablePrimitive,
490{
491 /// Creates a non-zero if the given value is not zero.
492 #[stable(feature = "nonzero", since = "1.28.0")]
493 #[rustc_const_stable(feature = "const_nonzero_int_methods", since = "1.47.0")]
494 #[must_use]
495 #[inline]
496 pub const fn new(n: T) -> Option<Self> {
497 // SAFETY: Memory layout optimization guarantees that `Option<NonZero<T>>` has
498 // the same layout and size as `T`, with `0` representing `None`.
499 unsafe { intrinsics::transmute_unchecked(n) }
500 }
501
502 /// Creates a non-zero without checking whether the value is non-zero.
503 /// This results in undefined behavior if the value is zero.
504 ///
505 /// # Safety
506 ///
507 /// The value must not be zero.
508 #[stable(feature = "nonzero", since = "1.28.0")]
509 #[rustc_const_stable(feature = "nonzero", since = "1.28.0")]
510 #[must_use]
511 #[inline]
512 #[track_caller]
513 pub const unsafe fn new_unchecked(n: T) -> Self {
514 match Self::new(n) {
515 Some(n) => n,
516 None => {
517 // SAFETY: The caller guarantees that `n` is non-zero, so this is unreachable.
518 unsafe {
519 ub_checks::assert_unsafe_precondition!(
520 check_language_ub,
521 "NonZero::new_unchecked requires the argument to be non-zero",
522 () => false,
523 );
524 intrinsics::unreachable()
525 }
526 }
527 }
528 }
529
530 /// Converts a reference to a non-zero mutable reference
531 /// if the referenced value is not zero.
532 #[unstable(feature = "nonzero_from_mut", issue = "106290")]
533 #[must_use]
534 #[inline]
535 pub fn from_mut(n: &mut T) -> Option<&mut Self> {
536 // SAFETY: Memory layout optimization guarantees that `Option<NonZero<T>>` has
537 // the same layout and size as `T`, with `0` representing `None`.
538 let opt_n = unsafe { &mut *(ptr::from_mut(n).cast::<Option<Self>>()) };
539
540 opt_n.as_mut()
541 }
542
543 /// Converts a mutable reference to a non-zero mutable reference
544 /// without checking whether the referenced value is non-zero.
545 /// This results in undefined behavior if the referenced value is zero.
546 ///
547 /// # Safety
548 ///
549 /// The referenced value must not be zero.
550 #[unstable(feature = "nonzero_from_mut", issue = "106290")]
551 #[must_use]
552 #[inline]
553 #[track_caller]
554 pub unsafe fn from_mut_unchecked(n: &mut T) -> &mut Self {
555 match Self::from_mut(n) {
556 Some(n) => n,
557 None => {
558 // SAFETY: The caller guarantees that `n` references a value that is non-zero, so this is unreachable.
559 unsafe {
560 ub_checks::assert_unsafe_precondition!(
561 check_library_ub,
562 "NonZero::from_mut_unchecked requires the argument to dereference as non-zero",
563 () => false,
564 );
565 intrinsics::unreachable()
566 }
567 }
568 }
569 }
570
571 /// Implementation of `From<&NonZero<T>> for &T`.
572 #[must_use]
573 #[inline]
574 fn as_ref(&self) -> &T {
575 // SAFETY: `repr(transparent)` ensures that `NonZero<T>` has same layout as `T`
576 unsafe { &*(ptr::from_ref(self).cast::<T>()) }
577 }
578
579 /// Implementation of `TryFrom<&T> for &NonZero<T>`.
580 #[must_use]
581 #[inline]
582 fn from_ref(n: &T) -> Option<&Self> {
583 // SAFETY: Memory layout optimization guarantees that `Option<NonZero<T>>` has
584 // the same layout and size as `T`, with `0` representing `None`.
585 let opt_n = unsafe { &*(ptr::from_ref(n).cast::<Option<Self>>()) };
586
587 opt_n.as_ref()
588 }
589
590 /// Implementation of `TryFrom<&[T]> for &[NonZero<T>]`.
591 #[must_use]
592 #[inline]
593 fn from_slice(n: &[T]) -> Option<&[Self]> {
594 if n.iter().all(|x| NonZero::new(*x).is_some()) {
595 // SAFETY: We explicitly checked that all elements are nonzero, and because of `repr(transparent)`
596 // the layout remains unchanged
597 Some(unsafe { slice::from_raw_parts(n.as_ptr().cast::<NonZero<T>>(), n.len()) })
598 } else {
599 None
600 }
601 }
602
603 /// Implementation of `TryFrom<[T; N]> for [NonZero<T>; N]`.
604 #[must_use]
605 #[inline]
606 fn from_array<const N: usize>(n: [T; N]) -> Option<[Self; N]> {
607 n.try_map(NonZero::new)
608 }
609
610 /// Returns the contained value as a primitive type.
611 #[stable(feature = "nonzero", since = "1.28.0")]
612 #[rustc_const_stable(feature = "const_nonzero_get", since = "1.34.0")]
613 #[inline]
614 pub const fn get(self) -> T {
615 // Rustc can set range metadata only if it loads `self` from
616 // memory somewhere. If the value of `self` was from by-value argument
617 // of some not-inlined function, LLVM don't have range metadata
618 // to understand that the value cannot be zero.
619 //
620 // Using the transmute `assume`s the range at runtime.
621 //
622 // Even once LLVM supports `!range` metadata for function arguments
623 // (see <https://github.com/llvm/llvm-project/issues/76628>), this can't
624 // be `.0` because MCP#807 bans field-projecting into `scalar_valid_range`
625 // types, and it arguably wouldn't want to be anyway because if this is
626 // MIR-inlined, there's no opportunity to put that argument metadata anywhere.
627 //
628 // The good answer here will eventually be pattern types, which will hopefully
629 // allow it to go back to `.0`, maybe with a cast of some sort.
630 //
631 // SAFETY: `ZeroablePrimitive` guarantees that the size and bit validity
632 // of `.0` is such that this transmute is sound.
633 unsafe { intrinsics::transmute_unchecked(self) }
634 }
635}
636
637impl<T, const N: usize> [NonZero<T>; N]
638where
639 T: ZeroablePrimitive,
640{
641 /// Implementation of `From<[NonZero<T>; N]> for [T; N]`.
642 #[must_use]
643 #[inline]
644 fn into_zeroable(self) -> [T; N] {
645 self.map(NonZero::get)
646 }
647}
648
649macro_rules! nonzero_integer {
650 (
651 #[$stability:meta]
652 Self = $Ty:ident,
653 Primitive = $signedness:ident $Int:ident,
654 SignedPrimitive = $Sint:ty,
655 UnsignedPrimitive = $Uint:ty,
656
657 // Used in doc comments.
658 rot = $rot:literal,
659 rot_op = $rot_op:literal,
660 rot_result = $rot_result:literal,
661 swap_op = $swap_op:literal,
662 swapped = $swapped:literal,
663 reversed = $reversed:literal,
664 leading_zeros_test = $leading_zeros_test:expr,
665 ) => {
666 #[doc = sign_dependent_expr!{
667 $signedness ?
668 if signed {
669 concat!("An [`", stringify!($Int), "`] that is known not to equal zero.")
670 }
671 if unsigned {
672 concat!("A [`", stringify!($Int), "`] that is known not to equal zero.")
673 }
674 }]
675 ///
676 /// This enables some memory layout optimization.
677 #[doc = concat!("For example, `Option<", stringify!($Ty), ">` is the same size as `", stringify!($Int), "`:")]
678 ///
679 /// ```rust
680 #[doc = concat!("assert_eq!(size_of::<Option<core::num::", stringify!($Ty), ">>(), size_of::<", stringify!($Int), ">());")]
681 /// ```
682 ///
683 /// # Layout
684 ///
685 #[doc = concat!("`", stringify!($Ty), "` is guaranteed to have the same layout and bit validity as `", stringify!($Int), "`")]
686 /// with the exception that `0` is not a valid instance.
687 #[doc = concat!("`Option<", stringify!($Ty), ">` is guaranteed to be ABI-compatible with `", stringify!($Int), "`,")]
688 /// including in FFI.
689 ///
690 /// Thanks to the [null pointer optimization],
691 #[doc = concat!("`", stringify!($Ty), "` and `Option<", stringify!($Ty), ">`")]
692 /// are guaranteed to have the same size and alignment:
693 ///
694 /// ```
695 #[doc = concat!("use std::num::", stringify!($Ty), ";")]
696 ///
697 #[doc = concat!("assert_eq!(size_of::<", stringify!($Ty), ">(), size_of::<Option<", stringify!($Ty), ">>());")]
698 #[doc = concat!("assert_eq!(align_of::<", stringify!($Ty), ">(), align_of::<Option<", stringify!($Ty), ">>());")]
699 /// ```
700 ///
701 /// # Compile-time creation
702 ///
703 /// Since both [`Option::unwrap()`] and [`Option::expect()`] are `const`, it is possible to
704 /// define a new
705 #[doc = concat!("`", stringify!($Ty), "`")]
706 /// at compile time via:
707 /// ```
708 #[doc = concat!("use std::num::", stringify!($Ty), ";")]
709 ///
710 #[doc = concat!("const TEN: ", stringify!($Ty), " = ", stringify!($Ty) , r#"::new(10).expect("ten is non-zero");"#)]
711 /// ```
712 ///
713 /// [null pointer optimization]: crate::option#representation
714 #[$stability]
715 pub type $Ty = NonZero<$Int>;
716
717 impl NonZero<$Int> {
718 /// The size of this non-zero integer type in bits.
719 ///
720 #[doc = concat!("This value is equal to [`", stringify!($Int), "::BITS`].")]
721 ///
722 /// # Examples
723 ///
724 /// ```
725 /// # use std::num::NonZero;
726 /// #
727 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::BITS, ", stringify!($Int), "::BITS);")]
728 /// ```
729 #[stable(feature = "nonzero_bits", since = "1.67.0")]
730 pub const BITS: u32 = <$Int>::BITS;
731
732 /// Returns the number of leading zeros in the binary representation of `self`.
733 ///
734 /// On many architectures, this function can perform better than `leading_zeros()` on the underlying integer type, as special handling of zero can be avoided.
735 ///
736 /// # Examples
737 ///
738 /// ```
739 /// # use std::num::NonZero;
740 /// #
741 /// # fn main() { test().unwrap(); }
742 /// # fn test() -> Option<()> {
743 #[doc = concat!("let n = NonZero::<", stringify!($Int), ">::new(", $leading_zeros_test, ")?;")]
744 ///
745 /// assert_eq!(n.leading_zeros(), 0);
746 /// # Some(())
747 /// # }
748 /// ```
749 #[stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
750 #[rustc_const_stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
751 #[must_use = "this returns the result of the operation, \
752 without modifying the original"]
753 #[inline]
754 pub const fn leading_zeros(self) -> u32 {
755 // SAFETY: since `self` cannot be zero, it is safe to call `ctlz_nonzero`.
756 unsafe {
757 intrinsics::ctlz_nonzero(self.get() as $Uint)
758 }
759 }
760
761 /// Returns the number of trailing zeros in the binary representation
762 /// of `self`.
763 ///
764 /// On many architectures, this function can perform better than `trailing_zeros()` on the underlying integer type, as special handling of zero can be avoided.
765 ///
766 /// # Examples
767 ///
768 /// ```
769 /// # use std::num::NonZero;
770 /// #
771 /// # fn main() { test().unwrap(); }
772 /// # fn test() -> Option<()> {
773 #[doc = concat!("let n = NonZero::<", stringify!($Int), ">::new(0b0101000)?;")]
774 ///
775 /// assert_eq!(n.trailing_zeros(), 3);
776 /// # Some(())
777 /// # }
778 /// ```
779 #[stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
780 #[rustc_const_stable(feature = "nonzero_leading_trailing_zeros", since = "1.53.0")]
781 #[must_use = "this returns the result of the operation, \
782 without modifying the original"]
783 #[inline]
784 pub const fn trailing_zeros(self) -> u32 {
785 // SAFETY: since `self` cannot be zero, it is safe to call `cttz_nonzero`.
786 unsafe {
787 intrinsics::cttz_nonzero(self.get() as $Uint)
788 }
789 }
790
791 /// Returns `self` with only the most significant bit set.
792 ///
793 /// # Example
794 ///
795 /// ```
796 /// # use core::num::NonZero;
797 /// # fn main() { test().unwrap(); }
798 /// # fn test() -> Option<()> {
799 #[doc = concat!("let a = NonZero::<", stringify!($Int), ">::new(0b_01100100)?;")]
800 #[doc = concat!("let b = NonZero::<", stringify!($Int), ">::new(0b_01000000)?;")]
801 ///
802 /// assert_eq!(a.isolate_highest_one(), b);
803 /// # Some(())
804 /// # }
805 /// ```
806 #[stable(feature = "isolate_most_least_significant_one", since = "1.97.0")]
807 #[rustc_const_stable(feature = "isolate_most_least_significant_one", since = "1.97.0")]
808 #[must_use = "this returns the result of the operation, \
809 without modifying the original"]
810 #[inline(always)]
811 pub const fn isolate_highest_one(self) -> Self {
812 // SAFETY:
813 // `self` is non-zero, so masking to preserve only the most
814 // significant set bit will result in a non-zero `n`.
815 // and self.leading_zeros() is always < $INT::BITS since
816 // at least one of the bits in the number is not zero
817 unsafe {
818 let bit = (((1 as $Uint) << (<$Uint>::BITS - 1)).unchecked_shr(self.leading_zeros()));
819 NonZero::new_unchecked(bit as $Int)
820 }
821 }
822
823 /// Returns `self` with only the least significant bit set.
824 ///
825 /// # Example
826 ///
827 /// ```
828 /// # use core::num::NonZero;
829 /// # fn main() { test().unwrap(); }
830 /// # fn test() -> Option<()> {
831 #[doc = concat!("let a = NonZero::<", stringify!($Int), ">::new(0b_01100100)?;")]
832 #[doc = concat!("let b = NonZero::<", stringify!($Int), ">::new(0b_00000100)?;")]
833 ///
834 /// assert_eq!(a.isolate_lowest_one(), b);
835 /// # Some(())
836 /// # }
837 /// ```
838 #[stable(feature = "isolate_most_least_significant_one", since = "1.97.0")]
839 #[rustc_const_stable(feature = "isolate_most_least_significant_one", since = "1.97.0")]
840 #[must_use = "this returns the result of the operation, \
841 without modifying the original"]
842 #[inline(always)]
843 pub const fn isolate_lowest_one(self) -> Self {
844 let n = self.get();
845 let n = n & n.wrapping_neg();
846
847 // SAFETY: `self` is non-zero, so `self` with only its least
848 // significant set bit will remain non-zero.
849 unsafe { NonZero::new_unchecked(n) }
850 }
851
852 /// Returns the index of the highest bit set to one in `self`.
853 ///
854 #[doc = sign_dependent_expr!{
855 $signedness ?
856 if signed {
857 ""
858 }
859 if unsigned {
860 "Note that this is equivalent to [`ilog2`](Self::ilog2)."
861 }
862 }]
863 ///
864 /// # Examples
865 ///
866 /// ```
867 /// # use core::num::NonZero;
868 /// # fn main() { test().unwrap(); }
869 /// # fn test() -> Option<()> {
870 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1)?.highest_one(), 0);")]
871 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1_0000)?.highest_one(), 4);")]
872 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1_1111)?.highest_one(), 4);")]
873 /// # Some(())
874 /// # }
875 /// ```
876 #[stable(feature = "int_lowest_highest_one", since = "1.97.0")]
877 #[rustc_const_stable(feature = "int_lowest_highest_one", since = "1.97.0")]
878 #[must_use = "this returns the result of the operation, \
879 without modifying the original"]
880 #[inline(always)]
881 pub const fn highest_one(self) -> u32 {
882 Self::BITS - 1 - self.leading_zeros()
883 }
884
885 /// Returns the index of the lowest bit set to one in `self`.
886 ///
887 /// # Examples
888 ///
889 /// ```
890 /// # use core::num::NonZero;
891 /// # fn main() { test().unwrap(); }
892 /// # fn test() -> Option<()> {
893 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1)?.lowest_one(), 0);")]
894 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1_0000)?.lowest_one(), 4);")]
895 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1_1111)?.lowest_one(), 0);")]
896 /// # Some(())
897 /// # }
898 /// ```
899 #[stable(feature = "int_lowest_highest_one", since = "1.97.0")]
900 #[rustc_const_stable(feature = "int_lowest_highest_one", since = "1.97.0")]
901 #[must_use = "this returns the result of the operation, \
902 without modifying the original"]
903 #[inline(always)]
904 pub const fn lowest_one(self) -> u32 {
905 self.trailing_zeros()
906 }
907
908 /// Returns the number of ones in the binary representation of `self`.
909 ///
910 /// # Examples
911 ///
912 /// ```
913 /// # use std::num::NonZero;
914 /// #
915 /// # fn main() { test().unwrap(); }
916 /// # fn test() -> Option<()> {
917 #[doc = concat!("let a = NonZero::<", stringify!($Int), ">::new(0b100_0000)?;")]
918 #[doc = concat!("let b = NonZero::<", stringify!($Int), ">::new(0b100_0011)?;")]
919 ///
920 /// assert_eq!(a.count_ones(), NonZero::new(1)?);
921 /// assert_eq!(b.count_ones(), NonZero::new(3)?);
922 /// # Some(())
923 /// # }
924 /// ```
925 ///
926 #[stable(feature = "non_zero_count_ones", since = "1.86.0")]
927 #[rustc_const_stable(feature = "non_zero_count_ones", since = "1.86.0")]
928 #[doc(alias = "popcount")]
929 #[doc(alias = "popcnt")]
930 #[must_use = "this returns the result of the operation, \
931 without modifying the original"]
932 #[inline(always)]
933 pub const fn count_ones(self) -> NonZero<u32> {
934 // SAFETY:
935 // `self` is non-zero, which means it has at least one bit set, which means
936 // that the result of `count_ones` is non-zero.
937 unsafe { NonZero::new_unchecked(self.get().count_ones()) }
938 }
939
940 /// Shifts the bits to the left by a specified amount, `n`,
941 /// wrapping the truncated bits to the end of the resulting integer.
942 ///
943 /// Please note this isn't the same operation as the `<<` shifting operator!
944 ///
945 /// # Examples
946 ///
947 /// ```
948 /// #![feature(nonzero_bitwise)]
949 /// # use std::num::NonZero;
950 /// #
951 /// # fn main() { test().unwrap(); }
952 /// # fn test() -> Option<()> {
953 #[doc = concat!("let n = NonZero::new(", $rot_op, stringify!($Int), ")?;")]
954 #[doc = concat!("let m = NonZero::new(", $rot_result, ")?;")]
955 ///
956 #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
957 /// # Some(())
958 /// # }
959 /// ```
960 #[unstable(feature = "nonzero_bitwise", issue = "128281")]
961 #[must_use = "this returns the result of the operation, \
962 without modifying the original"]
963 #[inline(always)]
964 pub const fn rotate_left(self, n: u32) -> Self {
965 let result = self.get().rotate_left(n);
966 // SAFETY: Rotating bits preserves the property int > 0.
967 unsafe { Self::new_unchecked(result) }
968 }
969
970 /// Shifts the bits to the right by a specified amount, `n`,
971 /// wrapping the truncated bits to the beginning of the resulting
972 /// integer.
973 ///
974 /// Please note this isn't the same operation as the `>>` shifting operator!
975 ///
976 /// # Examples
977 ///
978 /// ```
979 /// #![feature(nonzero_bitwise)]
980 /// # use std::num::NonZero;
981 /// #
982 /// # fn main() { test().unwrap(); }
983 /// # fn test() -> Option<()> {
984 #[doc = concat!("let n = NonZero::new(", $rot_result, stringify!($Int), ")?;")]
985 #[doc = concat!("let m = NonZero::new(", $rot_op, ")?;")]
986 ///
987 #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
988 /// # Some(())
989 /// # }
990 /// ```
991 #[unstable(feature = "nonzero_bitwise", issue = "128281")]
992 #[must_use = "this returns the result of the operation, \
993 without modifying the original"]
994 #[inline(always)]
995 pub const fn rotate_right(self, n: u32) -> Self {
996 let result = self.get().rotate_right(n);
997 // SAFETY: Rotating bits preserves the property int > 0.
998 unsafe { Self::new_unchecked(result) }
999 }
1000
1001 /// Reverses the byte order of the integer.
1002 ///
1003 /// # Examples
1004 ///
1005 /// ```
1006 /// #![feature(nonzero_bitwise)]
1007 /// # use std::num::NonZero;
1008 /// #
1009 /// # fn main() { test().unwrap(); }
1010 /// # fn test() -> Option<()> {
1011 #[doc = concat!("let n = NonZero::new(", $swap_op, stringify!($Int), ")?;")]
1012 /// let m = n.swap_bytes();
1013 ///
1014 #[doc = concat!("assert_eq!(m, NonZero::new(", $swapped, ")?);")]
1015 /// # Some(())
1016 /// # }
1017 /// ```
1018 #[unstable(feature = "nonzero_bitwise", issue = "128281")]
1019 #[must_use = "this returns the result of the operation, \
1020 without modifying the original"]
1021 #[inline(always)]
1022 pub const fn swap_bytes(self) -> Self {
1023 let result = self.get().swap_bytes();
1024 // SAFETY: Shuffling bytes preserves the property int > 0.
1025 unsafe { Self::new_unchecked(result) }
1026 }
1027
1028 /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
1029 /// second least-significant bit becomes second most-significant bit, etc.
1030 ///
1031 /// # Examples
1032 ///
1033 /// ```
1034 /// #![feature(nonzero_bitwise)]
1035 /// # use std::num::NonZero;
1036 /// #
1037 /// # fn main() { test().unwrap(); }
1038 /// # fn test() -> Option<()> {
1039 #[doc = concat!("let n = NonZero::new(", $swap_op, stringify!($Int), ")?;")]
1040 /// let m = n.reverse_bits();
1041 ///
1042 #[doc = concat!("assert_eq!(m, NonZero::new(", $reversed, ")?);")]
1043 /// # Some(())
1044 /// # }
1045 /// ```
1046 #[unstable(feature = "nonzero_bitwise", issue = "128281")]
1047 #[must_use = "this returns the result of the operation, \
1048 without modifying the original"]
1049 #[inline(always)]
1050 pub const fn reverse_bits(self) -> Self {
1051 let result = self.get().reverse_bits();
1052 // SAFETY: Reversing bits preserves the property int > 0.
1053 unsafe { Self::new_unchecked(result) }
1054 }
1055
1056 /// Converts an integer from big endian to the target's endianness.
1057 ///
1058 /// On big endian this is a no-op. On little endian the bytes are
1059 /// swapped.
1060 ///
1061 /// # Examples
1062 ///
1063 /// ```
1064 /// #![feature(nonzero_bitwise)]
1065 /// # use std::num::NonZero;
1066 #[doc = concat!("use std::num::", stringify!($Ty), ";")]
1067 /// #
1068 /// # fn main() { test().unwrap(); }
1069 /// # fn test() -> Option<()> {
1070 #[doc = concat!("let n = NonZero::new(0x1A", stringify!($Int), ")?;")]
1071 ///
1072 /// if cfg!(target_endian = "big") {
1073 #[doc = concat!(" assert_eq!(", stringify!($Ty), "::from_be(n), n)")]
1074 /// } else {
1075 #[doc = concat!(" assert_eq!(", stringify!($Ty), "::from_be(n), n.swap_bytes())")]
1076 /// }
1077 /// # Some(())
1078 /// # }
1079 /// ```
1080 #[unstable(feature = "nonzero_bitwise", issue = "128281")]
1081 #[must_use]
1082 #[inline(always)]
1083 pub const fn from_be(x: Self) -> Self {
1084 let result = $Int::from_be(x.get());
1085 // SAFETY: Shuffling bytes preserves the property int > 0.
1086 unsafe { Self::new_unchecked(result) }
1087 }
1088
1089 /// Converts an integer from little endian to the target's endianness.
1090 ///
1091 /// On little endian this is a no-op. On big endian the bytes are
1092 /// swapped.
1093 ///
1094 /// # Examples
1095 ///
1096 /// ```
1097 /// #![feature(nonzero_bitwise)]
1098 /// # use std::num::NonZero;
1099 #[doc = concat!("use std::num::", stringify!($Ty), ";")]
1100 /// #
1101 /// # fn main() { test().unwrap(); }
1102 /// # fn test() -> Option<()> {
1103 #[doc = concat!("let n = NonZero::new(0x1A", stringify!($Int), ")?;")]
1104 ///
1105 /// if cfg!(target_endian = "little") {
1106 #[doc = concat!(" assert_eq!(", stringify!($Ty), "::from_le(n), n)")]
1107 /// } else {
1108 #[doc = concat!(" assert_eq!(", stringify!($Ty), "::from_le(n), n.swap_bytes())")]
1109 /// }
1110 /// # Some(())
1111 /// # }
1112 /// ```
1113 #[unstable(feature = "nonzero_bitwise", issue = "128281")]
1114 #[must_use]
1115 #[inline(always)]
1116 pub const fn from_le(x: Self) -> Self {
1117 let result = $Int::from_le(x.get());
1118 // SAFETY: Shuffling bytes preserves the property int > 0.
1119 unsafe { Self::new_unchecked(result) }
1120 }
1121
1122 /// Converts `self` to big endian from the target's endianness.
1123 ///
1124 /// On big endian this is a no-op. On little endian the bytes are
1125 /// swapped.
1126 ///
1127 /// # Examples
1128 ///
1129 /// ```
1130 /// #![feature(nonzero_bitwise)]
1131 /// # use std::num::NonZero;
1132 /// #
1133 /// # fn main() { test().unwrap(); }
1134 /// # fn test() -> Option<()> {
1135 #[doc = concat!("let n = NonZero::new(0x1A", stringify!($Int), ")?;")]
1136 ///
1137 /// if cfg!(target_endian = "big") {
1138 /// assert_eq!(n.to_be(), n)
1139 /// } else {
1140 /// assert_eq!(n.to_be(), n.swap_bytes())
1141 /// }
1142 /// # Some(())
1143 /// # }
1144 /// ```
1145 #[unstable(feature = "nonzero_bitwise", issue = "128281")]
1146 #[must_use = "this returns the result of the operation, \
1147 without modifying the original"]
1148 #[inline(always)]
1149 pub const fn to_be(self) -> Self {
1150 let result = self.get().to_be();
1151 // SAFETY: Shuffling bytes preserves the property int > 0.
1152 unsafe { Self::new_unchecked(result) }
1153 }
1154
1155 /// Converts `self` to little endian from the target's endianness.
1156 ///
1157 /// On little endian this is a no-op. On big endian the bytes are
1158 /// swapped.
1159 ///
1160 /// # Examples
1161 ///
1162 /// ```
1163 /// #![feature(nonzero_bitwise)]
1164 /// # use std::num::NonZero;
1165 /// #
1166 /// # fn main() { test().unwrap(); }
1167 /// # fn test() -> Option<()> {
1168 #[doc = concat!("let n = NonZero::new(0x1A", stringify!($Int), ")?;")]
1169 ///
1170 /// if cfg!(target_endian = "little") {
1171 /// assert_eq!(n.to_le(), n)
1172 /// } else {
1173 /// assert_eq!(n.to_le(), n.swap_bytes())
1174 /// }
1175 /// # Some(())
1176 /// # }
1177 /// ```
1178 #[unstable(feature = "nonzero_bitwise", issue = "128281")]
1179 #[must_use = "this returns the result of the operation, \
1180 without modifying the original"]
1181 #[inline(always)]
1182 pub const fn to_le(self) -> Self {
1183 let result = self.get().to_le();
1184 // SAFETY: Shuffling bytes preserves the property int > 0.
1185 unsafe { Self::new_unchecked(result) }
1186 }
1187
1188 nonzero_integer_signedness_dependent_methods! {
1189 Primitive = $signedness $Int,
1190 SignedPrimitive = $Sint,
1191 UnsignedPrimitive = $Uint,
1192 }
1193
1194 /// Multiplies two non-zero integers together.
1195 /// Checks for overflow and returns [`None`] on overflow.
1196 /// As a consequence, the result cannot wrap to zero.
1197 ///
1198 /// # Examples
1199 ///
1200 /// ```
1201 /// # use std::num::NonZero;
1202 /// #
1203 /// # fn main() { test().unwrap(); }
1204 /// # fn test() -> Option<()> {
1205 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1206 #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1207 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1208 ///
1209 /// assert_eq!(Some(four), two.checked_mul(two));
1210 /// assert_eq!(None, max.checked_mul(two));
1211 /// # Some(())
1212 /// # }
1213 /// ```
1214 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1215 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1216 #[must_use = "this returns the result of the operation, \
1217 without modifying the original"]
1218 #[inline]
1219 pub const fn checked_mul(self, other: Self) -> Option<Self> {
1220 if let Some(result) = self.get().checked_mul(other.get()) {
1221 // SAFETY:
1222 // - `checked_mul` returns `None` on overflow
1223 // - `self` and `other` are non-zero
1224 // - the only way to get zero from a multiplication without overflow is for one
1225 // of the sides to be zero
1226 //
1227 // So the result cannot be zero.
1228 Some(unsafe { Self::new_unchecked(result) })
1229 } else {
1230 None
1231 }
1232 }
1233
1234 /// Multiplies two non-zero integers together.
1235 #[doc = concat!("Return [`NonZero::<", stringify!($Int), ">::MAX`] on overflow.")]
1236 ///
1237 /// # Examples
1238 ///
1239 /// ```
1240 /// # use std::num::NonZero;
1241 /// #
1242 /// # fn main() { test().unwrap(); }
1243 /// # fn test() -> Option<()> {
1244 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1245 #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1246 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1247 ///
1248 /// assert_eq!(four, two.saturating_mul(two));
1249 /// assert_eq!(max, four.saturating_mul(max));
1250 /// # Some(())
1251 /// # }
1252 /// ```
1253 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1254 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1255 #[must_use = "this returns the result of the operation, \
1256 without modifying the original"]
1257 #[inline]
1258 pub const fn saturating_mul(self, other: Self) -> Self {
1259 // SAFETY:
1260 // - `saturating_mul` returns `u*::MAX`/`i*::MAX`/`i*::MIN` on overflow/underflow,
1261 // all of which are non-zero
1262 // - `self` and `other` are non-zero
1263 // - the only way to get zero from a multiplication without overflow is for one
1264 // of the sides to be zero
1265 //
1266 // So the result cannot be zero.
1267 unsafe { Self::new_unchecked(self.get().saturating_mul(other.get())) }
1268 }
1269
1270 /// Multiplies two non-zero integers together,
1271 /// assuming overflow cannot occur.
1272 /// Overflow is unchecked, and it is undefined behavior to overflow
1273 /// *even if the result would wrap to a non-zero value*.
1274 ///
1275 /// # Safety
1276 ///
1277 /// This results in undefined behavior when
1278 #[doc = sign_dependent_expr!{
1279 $signedness ?
1280 if signed {
1281 concat!("`self * rhs > ", stringify!($Int), "::MAX`, ",
1282 "or `self * rhs < ", stringify!($Int), "::MIN`.")
1283 }
1284 if unsigned {
1285 concat!("`self * rhs > ", stringify!($Int), "::MAX`.")
1286 }
1287 }]
1288 ///
1289 /// # Examples
1290 ///
1291 /// ```
1292 /// #![feature(nonzero_ops)]
1293 ///
1294 /// # use std::num::NonZero;
1295 /// #
1296 /// # fn main() { test().unwrap(); }
1297 /// # fn test() -> Option<()> {
1298 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1299 #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1300 ///
1301 /// assert_eq!(four, unsafe { two.unchecked_mul(two) });
1302 /// # Some(())
1303 /// # }
1304 /// ```
1305 #[unstable(feature = "nonzero_ops", issue = "84186")]
1306 #[must_use = "this returns the result of the operation, \
1307 without modifying the original"]
1308 #[inline]
1309 pub const unsafe fn unchecked_mul(self, other: Self) -> Self {
1310 // SAFETY: The caller ensures there is no overflow.
1311 unsafe { Self::new_unchecked(self.get().unchecked_mul(other.get())) }
1312 }
1313
1314 /// Raises non-zero value to an integer power.
1315 /// Checks for overflow and returns [`None`] on overflow.
1316 /// As a consequence, the result cannot wrap to zero.
1317 ///
1318 /// # Examples
1319 ///
1320 /// ```
1321 /// # use std::num::NonZero;
1322 /// #
1323 /// # fn main() { test().unwrap(); }
1324 /// # fn test() -> Option<()> {
1325 #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ")?;")]
1326 #[doc = concat!("let twenty_seven = NonZero::new(27", stringify!($Int), ")?;")]
1327 #[doc = concat!("let half_max = NonZero::new(", stringify!($Int), "::MAX / 2)?;")]
1328 ///
1329 /// assert_eq!(Some(twenty_seven), three.checked_pow(3));
1330 /// assert_eq!(None, half_max.checked_pow(3));
1331 /// # Some(())
1332 /// # }
1333 /// ```
1334 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1335 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1336 #[must_use = "this returns the result of the operation, \
1337 without modifying the original"]
1338 #[inline]
1339 pub const fn checked_pow(self, other: u32) -> Option<Self> {
1340 if let Some(result) = self.get().checked_pow(other) {
1341 // SAFETY:
1342 // - `checked_pow` returns `None` on overflow/underflow
1343 // - `self` is non-zero
1344 // - the only way to get zero from an exponentiation without overflow is
1345 // for base to be zero
1346 //
1347 // So the result cannot be zero.
1348 Some(unsafe { Self::new_unchecked(result) })
1349 } else {
1350 None
1351 }
1352 }
1353
1354 /// Raise non-zero value to an integer power.
1355 #[doc = sign_dependent_expr!{
1356 $signedness ?
1357 if signed {
1358 concat!("Return [`NonZero::<", stringify!($Int), ">::MIN`] ",
1359 "or [`NonZero::<", stringify!($Int), ">::MAX`] on overflow.")
1360 }
1361 if unsigned {
1362 concat!("Return [`NonZero::<", stringify!($Int), ">::MAX`] on overflow.")
1363 }
1364 }]
1365 ///
1366 /// # Examples
1367 ///
1368 /// ```
1369 /// # use std::num::NonZero;
1370 /// #
1371 /// # fn main() { test().unwrap(); }
1372 /// # fn test() -> Option<()> {
1373 #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ")?;")]
1374 #[doc = concat!("let twenty_seven = NonZero::new(27", stringify!($Int), ")?;")]
1375 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1376 ///
1377 /// assert_eq!(twenty_seven, three.saturating_pow(3));
1378 /// assert_eq!(max, max.saturating_pow(3));
1379 /// # Some(())
1380 /// # }
1381 /// ```
1382 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1383 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1384 #[must_use = "this returns the result of the operation, \
1385 without modifying the original"]
1386 #[inline]
1387 pub const fn saturating_pow(self, other: u32) -> Self {
1388 // SAFETY:
1389 // - `saturating_pow` returns `u*::MAX`/`i*::MAX`/`i*::MIN` on overflow/underflow,
1390 // all of which are non-zero
1391 // - `self` is non-zero
1392 // - the only way to get zero from an exponentiation without overflow is
1393 // for base to be zero
1394 //
1395 // So the result cannot be zero.
1396 unsafe { Self::new_unchecked(self.get().saturating_pow(other)) }
1397 }
1398
1399 /// Parses a non-zero integer from an ASCII-byte slice with decimal digits.
1400 ///
1401 /// The characters are expected to be an optional
1402 #[doc = sign_dependent_expr!{
1403 $signedness ?
1404 if signed {
1405 " `+` or `-` "
1406 }
1407 if unsigned {
1408 " `+` "
1409 }
1410 }]
1411 /// sign followed by only digits. Leading and trailing non-digit characters (including
1412 /// whitespace) represent an error. Underscores (which are accepted in Rust literals)
1413 /// also represent an error.
1414 ///
1415 /// # Examples
1416 ///
1417 /// ```
1418 /// #![feature(int_from_ascii)]
1419 ///
1420 /// # use std::num::NonZero;
1421 /// #
1422 /// # fn main() { test().unwrap(); }
1423 /// # fn test() -> Option<()> {
1424 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::from_ascii_bytes(b\"+10\"), Ok(NonZero::new(10)?));")]
1425 /// # Some(())
1426 /// # }
1427 /// ```
1428 ///
1429 /// Trailing space returns error:
1430 ///
1431 /// ```
1432 /// #![feature(int_from_ascii)]
1433 ///
1434 /// # use std::num::NonZero;
1435 /// #
1436 #[doc = concat!("assert!(NonZero::<", stringify!($Int), ">::from_ascii_bytes(b\"1 \").is_err());")]
1437 /// ```
1438 #[unstable(feature = "int_from_ascii", issue = "134821")]
1439 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
1440 #[inline]
1441 pub const fn from_ascii_bytes<T>(src: T) -> Result<Self, ParseIntError>
1442 where
1443 T: [const] AsRef<[u8]> + [const] crate::marker::Destruct
1444 {
1445 Self::from_ascii_bytes_radix_impl(src.as_ref(), 10)
1446 }
1447
1448 /// Parses a non-zero integer from an ASCII-byte slice with digits in a given base.
1449 ///
1450 /// The characters are expected to be an optional
1451 #[doc = sign_dependent_expr!{
1452 $signedness ?
1453 if signed {
1454 " `+` or `-` "
1455 }
1456 if unsigned {
1457 " `+` "
1458 }
1459 }]
1460 /// sign followed by only digits. Leading and trailing non-digit characters (including
1461 /// whitespace) represent an error. Underscores (which are accepted in Rust literals)
1462 /// also represent an error.
1463 ///
1464 /// Digits are a subset of these characters, depending on `radix`:
1465 ///
1466 /// - `0-9`
1467 /// - `a-z`
1468 /// - `A-Z`
1469 ///
1470 /// # Panics
1471 ///
1472 /// This method panics if `radix` is not in the range from 2 to 36.
1473 ///
1474 /// # Examples
1475 ///
1476 /// ```
1477 /// #![feature(int_from_ascii)]
1478 ///
1479 /// # use std::num::NonZero;
1480 /// #
1481 /// # fn main() { test().unwrap(); }
1482 /// # fn test() -> Option<()> {
1483 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::from_ascii_bytes_radix(b\"A\", 16), Ok(NonZero::new(10)?));")]
1484 /// # Some(())
1485 /// # }
1486 /// ```
1487 ///
1488 /// Trailing space returns error:
1489 ///
1490 /// ```
1491 /// #![feature(int_from_ascii)]
1492 ///
1493 /// # use std::num::NonZero;
1494 /// #
1495 #[doc = concat!("assert!(NonZero::<", stringify!($Int), ">::from_ascii_bytes_radix(b\"1 \", 10).is_err());")]
1496 /// ```
1497 #[unstable(feature = "int_from_ascii", issue = "134821")]
1498 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
1499 #[inline]
1500 pub const fn from_ascii_bytes_radix<T>(src: T, radix: u32) -> Result<Self, ParseIntError>
1501 where
1502 T: [const] AsRef<[u8]> + [const] crate::marker::Destruct
1503 {
1504 Self::from_ascii_bytes_radix_impl(src.as_ref(), radix)
1505 }
1506
1507 #[inline]
1508 const fn from_ascii_bytes_radix_impl(src: &[u8], radix: u32) -> Result<Self, ParseIntError> {
1509 let n = match <$Int>::from_ascii_bytes_radix_impl(src, radix) {
1510 Ok(n) => n,
1511 Err(err) => return Err(err),
1512 };
1513 if let Some(n) = Self::new(n) {
1514 Ok(n)
1515 } else {
1516 Err(ParseIntError { kind: IntErrorKind::Zero })
1517 }
1518 }
1519
1520 /// Parses a non-zero integer from a string slice with digits in a given base.
1521 ///
1522 /// The string is expected to be an optional
1523 #[doc = sign_dependent_expr!{
1524 $signedness ?
1525 if signed {
1526 " `+` or `-` "
1527 }
1528 if unsigned {
1529 " `+` "
1530 }
1531 }]
1532 /// sign followed by only digits. Leading and trailing non-digit characters (including
1533 /// whitespace) represent an error. Underscores (which are accepted in Rust literals)
1534 /// also represent an error.
1535 ///
1536 /// Digits are a subset of these characters, depending on `radix`:
1537 ///
1538 /// - `0-9`
1539 /// - `a-z`
1540 /// - `A-Z`
1541 ///
1542 /// # Panics
1543 ///
1544 /// This method panics if `radix` is not in the range from 2 to 36.
1545 ///
1546 /// # Examples
1547 ///
1548 /// ```
1549 /// # use std::num::NonZero;
1550 /// #
1551 /// # fn main() { test().unwrap(); }
1552 /// # fn test() -> Option<()> {
1553 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::from_str_radix(\"A\", 16), Ok(NonZero::new(10)?));")]
1554 /// # Some(())
1555 /// # }
1556 /// ```
1557 ///
1558 /// Trailing space returns error:
1559 ///
1560 /// ```
1561 /// # use std::num::NonZero;
1562 /// #
1563 #[doc = concat!("assert!(NonZero::<", stringify!($Int), ">::from_str_radix(\"1 \", 10).is_err());")]
1564 /// ```
1565 #[stable(feature = "nonzero_from_str_radix", since = "1.98.0")]
1566 #[rustc_const_stable(feature = "nonzero_from_str_radix", since = "1.98.0")]
1567 #[inline]
1568 pub const fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> {
1569 Self::from_ascii_bytes_radix_impl(src.as_bytes(), radix)
1570 }
1571 }
1572
1573 #[stable(feature = "nonzero_parse", since = "1.35.0")]
1574 #[rustc_const_unstable(feature = "const_convert", issue = "143773")]
1575 const impl FromStr for NonZero<$Int> {
1576 type Err = ParseIntError;
1577
1578 /// Parses a non-zero integer from a string slice with decimal digits.
1579 ///
1580 /// The characters are expected to be an optional
1581 #[doc = sign_dependent_expr!{
1582 $signedness ?
1583 if signed {
1584 " `+` or `-` "
1585 }
1586 if unsigned {
1587 " `+` "
1588 }
1589 }]
1590 /// sign followed by only digits. Leading and trailing non-digit characters (including
1591 /// whitespace) represent an error. Underscores (which are accepted in Rust literals)
1592 /// also represent an error.
1593 ///
1594 /// # Examples
1595 ///
1596 /// ```
1597 /// use std::num::NonZero;
1598 /// use std::str::FromStr;
1599 ///
1600 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::from_str(\"+10\"), Ok(NonZero::new(10).unwrap()));")]
1601 /// ```
1602 ///
1603 /// Trailing space returns error:
1604 ///
1605 /// ```
1606 /// use std::num::NonZero;
1607 /// use std::str::FromStr;
1608 ///
1609 #[doc = concat!("assert!(NonZero::<", stringify!($Int), ">::from_str(\"1 \").is_err());")]
1610 /// ```
1611 #[inline]
1612 fn from_str(src: &str) -> Result<Self, Self::Err> {
1613 Self::from_str_radix(src, 10)
1614 }
1615 }
1616
1617 nonzero_integer_signedness_dependent_impls!($signedness $Int);
1618 };
1619
1620 (
1621 Self = $Ty:ident,
1622 Primitive = unsigned $Int:ident,
1623 SignedPrimitive = $Sint:ident,
1624 rot = $rot:literal,
1625 rot_op = $rot_op:literal,
1626 rot_result = $rot_result:literal,
1627 swap_op = $swap_op:literal,
1628 swapped = $swapped:literal,
1629 reversed = $reversed:literal,
1630 $(,)?
1631 ) => {
1632 nonzero_integer! {
1633 #[stable(feature = "nonzero", since = "1.28.0")]
1634 Self = $Ty,
1635 Primitive = unsigned $Int,
1636 SignedPrimitive = $Sint,
1637 UnsignedPrimitive = $Int,
1638 rot = $rot,
1639 rot_op = $rot_op,
1640 rot_result = $rot_result,
1641 swap_op = $swap_op,
1642 swapped = $swapped,
1643 reversed = $reversed,
1644 leading_zeros_test = concat!(stringify!($Int), "::MAX"),
1645 }
1646 };
1647
1648 (
1649 Self = $Ty:ident,
1650 Primitive = signed $Int:ident,
1651 UnsignedPrimitive = $Uint:ident,
1652 rot = $rot:literal,
1653 rot_op = $rot_op:literal,
1654 rot_result = $rot_result:literal,
1655 swap_op = $swap_op:literal,
1656 swapped = $swapped:literal,
1657 reversed = $reversed:literal,
1658 ) => {
1659 nonzero_integer! {
1660 #[stable(feature = "signed_nonzero", since = "1.34.0")]
1661 Self = $Ty,
1662 Primitive = signed $Int,
1663 SignedPrimitive = $Int,
1664 UnsignedPrimitive = $Uint,
1665 rot = $rot,
1666 rot_op = $rot_op,
1667 rot_result = $rot_result,
1668 swap_op = $swap_op,
1669 swapped = $swapped,
1670 reversed = $reversed,
1671 leading_zeros_test = concat!("-1", stringify!($Int)),
1672 }
1673 };
1674}
1675
1676macro_rules! nonzero_integer_signedness_dependent_impls {
1677 // Impls for unsigned nonzero types only.
1678 (unsigned $Int:ty) => {
1679 #[stable(feature = "nonzero_div", since = "1.51.0")]
1680 #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1681 const impl Div<NonZero<$Int>> for $Int {
1682 type Output = $Int;
1683
1684 /// Same as `self / other.get()`, but because `other` is a `NonZero<_>`,
1685 /// there's never a runtime check for division-by-zero.
1686 ///
1687 /// This operation rounds towards zero, truncating any fractional
1688 /// part of the exact result, and cannot panic.
1689 #[doc(alias = "unchecked_div")]
1690 #[inline]
1691 fn div(self, other: NonZero<$Int>) -> $Int {
1692 // SAFETY: Division by zero is checked because `other` is non-zero,
1693 // and MIN/-1 is checked because `self` is an unsigned int.
1694 unsafe { intrinsics::unchecked_div(self, other.get()) }
1695 }
1696 }
1697
1698 #[stable(feature = "nonzero_div_assign", since = "1.79.0")]
1699 #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1700 const impl DivAssign<NonZero<$Int>> for $Int {
1701 /// Same as `self /= other.get()`, but because `other` is a `NonZero<_>`,
1702 /// there's never a runtime check for division-by-zero.
1703 ///
1704 /// This operation rounds towards zero, truncating any fractional
1705 /// part of the exact result, and cannot panic.
1706 #[inline]
1707 fn div_assign(&mut self, other: NonZero<$Int>) {
1708 *self = *self / other;
1709 }
1710 }
1711
1712 #[stable(feature = "nonzero_div", since = "1.51.0")]
1713 #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1714 const impl Rem<NonZero<$Int>> for $Int {
1715 type Output = $Int;
1716
1717 /// This operation satisfies `n % d == n - (n / d) * d`, and cannot panic.
1718 #[inline]
1719 fn rem(self, other: NonZero<$Int>) -> $Int {
1720 // SAFETY: Remainder by zero is checked because `other` is non-zero,
1721 // and MIN/-1 is checked because `self` is an unsigned int.
1722 unsafe { intrinsics::unchecked_rem(self, other.get()) }
1723 }
1724 }
1725
1726 #[stable(feature = "nonzero_div_assign", since = "1.79.0")]
1727 #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1728 const impl RemAssign<NonZero<$Int>> for $Int {
1729 /// This operation satisfies `n % d == n - (n / d) * d`, and cannot panic.
1730 #[inline]
1731 fn rem_assign(&mut self, other: NonZero<$Int>) {
1732 *self = *self % other;
1733 }
1734 }
1735 };
1736 // Impls for signed nonzero types only.
1737 (signed $Int:ty) => {
1738 #[stable(feature = "signed_nonzero_neg", since = "1.71.0")]
1739 #[rustc_const_unstable(feature = "const_ops", issue = "143802")]
1740 const impl Neg for NonZero<$Int> {
1741 type Output = Self;
1742
1743 #[inline]
1744 fn neg(self) -> Self {
1745 // SAFETY: negation of nonzero cannot yield zero values.
1746 unsafe { Self::new_unchecked(self.get().neg()) }
1747 }
1748 }
1749
1750 forward_ref_unop! { impl Neg, neg for NonZero<$Int>,
1751 #[stable(feature = "signed_nonzero_neg", since = "1.71.0")]
1752 #[rustc_const_unstable(feature = "const_ops", issue = "143802")] }
1753 };
1754}
1755
1756#[rustfmt::skip] // https://github.com/rust-lang/rustfmt/issues/5974
1757macro_rules! nonzero_integer_signedness_dependent_methods {
1758 // Associated items for unsigned nonzero types only.
1759 (
1760 Primitive = unsigned $Int:ident,
1761 SignedPrimitive = $Sint:ty,
1762 UnsignedPrimitive = $Uint:ty,
1763 ) => {
1764 /// The smallest value that can be represented by this non-zero
1765 /// integer type, 1.
1766 ///
1767 /// # Examples
1768 ///
1769 /// ```
1770 /// # use std::num::NonZero;
1771 /// #
1772 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::MIN.get(), 1", stringify!($Int), ");")]
1773 /// ```
1774 #[stable(feature = "nonzero_min_max", since = "1.70.0")]
1775 pub const MIN: Self = Self::new(1).unwrap();
1776
1777 /// The largest value that can be represented by this non-zero
1778 /// integer type,
1779 #[doc = concat!("equal to [`", stringify!($Int), "::MAX`].")]
1780 ///
1781 /// # Examples
1782 ///
1783 /// ```
1784 /// # use std::num::NonZero;
1785 /// #
1786 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::MAX.get(), ", stringify!($Int), "::MAX);")]
1787 /// ```
1788 #[stable(feature = "nonzero_min_max", since = "1.70.0")]
1789 pub const MAX: Self = Self::new(<$Int>::MAX).unwrap();
1790
1791 /// Adds an unsigned integer to a non-zero value.
1792 /// Checks for overflow and returns [`None`] on overflow.
1793 /// As a consequence, the result cannot wrap to zero.
1794 ///
1795 ///
1796 /// # Examples
1797 ///
1798 /// ```
1799 /// # use std::num::NonZero;
1800 /// #
1801 /// # fn main() { test().unwrap(); }
1802 /// # fn test() -> Option<()> {
1803 #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ")?;")]
1804 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1805 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1806 ///
1807 /// assert_eq!(Some(two), one.checked_add(1));
1808 /// assert_eq!(None, max.checked_add(1));
1809 /// # Some(())
1810 /// # }
1811 /// ```
1812 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1813 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1814 #[must_use = "this returns the result of the operation, \
1815 without modifying the original"]
1816 #[inline]
1817 pub const fn checked_add(self, other: $Int) -> Option<Self> {
1818 if let Some(result) = self.get().checked_add(other) {
1819 // SAFETY:
1820 // - `checked_add` returns `None` on overflow
1821 // - `self` is non-zero
1822 // - the only way to get zero from an addition without overflow is for both
1823 // sides to be zero
1824 //
1825 // So the result cannot be zero.
1826 Some(unsafe { Self::new_unchecked(result) })
1827 } else {
1828 None
1829 }
1830 }
1831
1832 /// Adds an unsigned integer to a non-zero value.
1833 #[doc = concat!("Return [`NonZero::<", stringify!($Int), ">::MAX`] on overflow.")]
1834 ///
1835 /// # Examples
1836 ///
1837 /// ```
1838 /// # use std::num::NonZero;
1839 /// #
1840 /// # fn main() { test().unwrap(); }
1841 /// # fn test() -> Option<()> {
1842 #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ")?;")]
1843 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1844 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1845 ///
1846 /// assert_eq!(two, one.saturating_add(1));
1847 /// assert_eq!(max, max.saturating_add(1));
1848 /// # Some(())
1849 /// # }
1850 /// ```
1851 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1852 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1853 #[must_use = "this returns the result of the operation, \
1854 without modifying the original"]
1855 #[inline]
1856 pub const fn saturating_add(self, other: $Int) -> Self {
1857 // SAFETY:
1858 // - `saturating_add` returns `u*::MAX` on overflow, which is non-zero
1859 // - `self` is non-zero
1860 // - the only way to get zero from an addition without overflow is for both
1861 // sides to be zero
1862 //
1863 // So the result cannot be zero.
1864 unsafe { Self::new_unchecked(self.get().saturating_add(other)) }
1865 }
1866
1867 /// Adds an unsigned integer to a non-zero value,
1868 /// assuming overflow cannot occur.
1869 /// Overflow is unchecked, and it is undefined behavior to overflow
1870 /// *even if the result would wrap to a non-zero value*.
1871 ///
1872 /// # Safety
1873 ///
1874 /// This results in undefined behavior when
1875 #[doc = concat!("`self + rhs > ", stringify!($Int), "::MAX`.")]
1876 ///
1877 /// # Examples
1878 ///
1879 /// ```
1880 /// #![feature(nonzero_ops)]
1881 ///
1882 /// # use std::num::NonZero;
1883 /// #
1884 /// # fn main() { test().unwrap(); }
1885 /// # fn test() -> Option<()> {
1886 #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ")?;")]
1887 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1888 ///
1889 /// assert_eq!(two, unsafe { one.unchecked_add(1) });
1890 /// # Some(())
1891 /// # }
1892 /// ```
1893 #[unstable(feature = "nonzero_ops", issue = "84186")]
1894 #[must_use = "this returns the result of the operation, \
1895 without modifying the original"]
1896 #[inline]
1897 pub const unsafe fn unchecked_add(self, other: $Int) -> Self {
1898 // SAFETY: The caller ensures there is no overflow.
1899 unsafe { Self::new_unchecked(self.get().unchecked_add(other)) }
1900 }
1901
1902 /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
1903 ///
1904 /// The result is guaranteed to be non-zero.
1905 ///
1906 /// # Examples
1907 ///
1908 /// ```
1909 /// # use std::num::NonZero;
1910 #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ").unwrap();")]
1911 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX).unwrap();")]
1912 /// assert_eq!(one.div_ceil(max), one);
1913 ///
1914 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ").unwrap();")]
1915 #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ").unwrap();")]
1916 /// assert_eq!(three.div_ceil(two), two);
1917 /// ```
1918 #[stable(feature = "unsigned_nonzero_div_ceil", since = "1.92.0")]
1919 #[rustc_const_stable(feature = "unsigned_nonzero_div_ceil", since = "1.92.0")]
1920 #[must_use = "this returns the result of the operation, \
1921 without modifying the original"]
1922 #[inline]
1923 pub const fn div_ceil(self, rhs: Self) -> Self {
1924 // An implementation of the function without calculating the remainder.
1925 // It is better than the implementation for normal integers, but it can only
1926 // be used here because of the possibility to subtract by one without overflow.
1927 let v = (self.get() - 1) / rhs.get() + 1;
1928 // SAFETY: ceiled division of two positive integers can never be zero.
1929 unsafe { Self::new_unchecked(v) }
1930 }
1931
1932 /// Returns the smallest power of two greater than or equal to `self`.
1933 /// Checks for overflow and returns [`None`]
1934 /// if the next power of two is greater than the type’s maximum value.
1935 /// As a consequence, the result cannot wrap to zero.
1936 ///
1937 /// # Examples
1938 ///
1939 /// ```
1940 /// # use std::num::NonZero;
1941 /// #
1942 /// # fn main() { test().unwrap(); }
1943 /// # fn test() -> Option<()> {
1944 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
1945 #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ")?;")]
1946 #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
1947 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
1948 ///
1949 /// assert_eq!(Some(two), two.checked_next_power_of_two() );
1950 /// assert_eq!(Some(four), three.checked_next_power_of_two() );
1951 /// assert_eq!(None, max.checked_next_power_of_two() );
1952 /// # Some(())
1953 /// # }
1954 /// ```
1955 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
1956 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
1957 #[must_use = "this returns the result of the operation, \
1958 without modifying the original"]
1959 #[inline]
1960 pub const fn checked_next_power_of_two(self) -> Option<Self> {
1961 if let Some(nz) = self.get().checked_next_power_of_two() {
1962 // SAFETY: The next power of two is positive
1963 // and overflow is checked.
1964 Some(unsafe { Self::new_unchecked(nz) })
1965 } else {
1966 None
1967 }
1968 }
1969
1970 /// Returns the base 2 logarithm of the number, rounded down.
1971 ///
1972 /// This is the same operation as
1973 #[doc = concat!("[`", stringify!($Int), "::ilog2`],")]
1974 /// except that it has no failure cases to worry about
1975 /// since this value can never be zero.
1976 ///
1977 /// Note that this is equivalent to [`highest_one`](Self::highest_one).
1978 ///
1979 /// # Examples
1980 ///
1981 /// ```
1982 /// # use std::num::NonZero;
1983 /// #
1984 /// # fn main() { test().unwrap(); }
1985 /// # fn test() -> Option<()> {
1986 #[doc = concat!("assert_eq!(NonZero::new(7", stringify!($Int), ")?.ilog2(), 2);")]
1987 #[doc = concat!("assert_eq!(NonZero::new(8", stringify!($Int), ")?.ilog2(), 3);")]
1988 #[doc = concat!("assert_eq!(NonZero::new(9", stringify!($Int), ")?.ilog2(), 3);")]
1989 /// # Some(())
1990 /// # }
1991 /// ```
1992 #[stable(feature = "int_log", since = "1.67.0")]
1993 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1994 #[must_use = "this returns the result of the operation, \
1995 without modifying the original"]
1996 #[inline]
1997 pub const fn ilog2(self) -> u32 {
1998 Self::BITS - 1 - self.leading_zeros()
1999 }
2000
2001 /// Returns the base 10 logarithm of the number, rounded down.
2002 ///
2003 /// This is the same operation as
2004 #[doc = concat!("[`", stringify!($Int), "::ilog10`],")]
2005 /// except that it has no failure cases to worry about
2006 /// since this value can never be zero.
2007 ///
2008 /// # Examples
2009 ///
2010 /// ```
2011 /// # use std::num::NonZero;
2012 /// #
2013 /// # fn main() { test().unwrap(); }
2014 /// # fn test() -> Option<()> {
2015 #[doc = concat!("assert_eq!(NonZero::new(99", stringify!($Int), ")?.ilog10(), 1);")]
2016 #[doc = concat!("assert_eq!(NonZero::new(100", stringify!($Int), ")?.ilog10(), 2);")]
2017 #[doc = concat!("assert_eq!(NonZero::new(101", stringify!($Int), ")?.ilog10(), 2);")]
2018 /// # Some(())
2019 /// # }
2020 /// ```
2021 #[stable(feature = "int_log", since = "1.67.0")]
2022 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
2023 #[must_use = "this returns the result of the operation, \
2024 without modifying the original"]
2025 #[inline]
2026 pub const fn ilog10(self) -> u32 {
2027 imp::int_log10::$Int(self)
2028 }
2029
2030 /// Calculates the midpoint (average) between `self` and `rhs`.
2031 ///
2032 /// `midpoint(a, b)` is `(a + b) >> 1` as if it were performed in a
2033 /// sufficiently-large signed integral type. This implies that the result is
2034 /// always rounded towards negative infinity and that no overflow will ever occur.
2035 ///
2036 /// # Examples
2037 ///
2038 /// ```
2039 /// # use std::num::NonZero;
2040 /// #
2041 /// # fn main() { test().unwrap(); }
2042 /// # fn test() -> Option<()> {
2043 #[doc = concat!("let one = NonZero::new(1", stringify!($Int), ")?;")]
2044 #[doc = concat!("let two = NonZero::new(2", stringify!($Int), ")?;")]
2045 #[doc = concat!("let four = NonZero::new(4", stringify!($Int), ")?;")]
2046 ///
2047 /// assert_eq!(one.midpoint(four), two);
2048 /// assert_eq!(four.midpoint(one), two);
2049 /// # Some(())
2050 /// # }
2051 /// ```
2052 #[stable(feature = "num_midpoint", since = "1.85.0")]
2053 #[rustc_const_stable(feature = "num_midpoint", since = "1.85.0")]
2054 #[must_use = "this returns the result of the operation, \
2055 without modifying the original"]
2056 #[doc(alias = "average_floor")]
2057 #[doc(alias = "average")]
2058 #[inline]
2059 pub const fn midpoint(self, rhs: Self) -> Self {
2060 // SAFETY: The only way to get `0` with midpoint is to have two opposite or
2061 // near opposite numbers: (-5, 5), (0, 1), (0, 0) which is impossible because
2062 // of the unsignedness of this number and also because `Self` is guaranteed to
2063 // never being 0.
2064 unsafe { Self::new_unchecked(self.get().midpoint(rhs.get())) }
2065 }
2066
2067 /// Returns `true` if and only if `self == (1 << k)` for some `k`.
2068 ///
2069 /// On many architectures, this function can perform better than `is_power_of_two()`
2070 /// on the underlying integer type, as special handling of zero can be avoided.
2071 ///
2072 /// # Examples
2073 ///
2074 /// ```
2075 /// # use std::num::NonZero;
2076 /// #
2077 /// # fn main() { test().unwrap(); }
2078 /// # fn test() -> Option<()> {
2079 #[doc = concat!("let eight = NonZero::new(8", stringify!($Int), ")?;")]
2080 /// assert!(eight.is_power_of_two());
2081 #[doc = concat!("let ten = NonZero::new(10", stringify!($Int), ")?;")]
2082 /// assert!(!ten.is_power_of_two());
2083 /// # Some(())
2084 /// # }
2085 /// ```
2086 #[must_use]
2087 #[stable(feature = "nonzero_is_power_of_two", since = "1.59.0")]
2088 #[rustc_const_stable(feature = "nonzero_is_power_of_two", since = "1.59.0")]
2089 #[inline]
2090 pub const fn is_power_of_two(self) -> bool {
2091 // LLVM 11 normalizes `unchecked_sub(x, 1) & x == 0` to the implementation seen here.
2092 // On the basic x86-64 target, this saves 3 instructions for the zero check.
2093 // On x86_64 with BMI1, being nonzero lets it codegen to `BLSR`, which saves an instruction
2094 // compared to the `POPCNT` implementation on the underlying integer type.
2095
2096 intrinsics::ctpop(self.get()) < 2
2097 }
2098
2099 /// Returns the square root of the number, rounded down.
2100 ///
2101 /// # Examples
2102 ///
2103 /// ```
2104 /// # use std::num::NonZero;
2105 /// #
2106 /// # fn main() { test().unwrap(); }
2107 /// # fn test() -> Option<()> {
2108 #[doc = concat!("let ten = NonZero::new(10", stringify!($Int), ")?;")]
2109 #[doc = concat!("let three = NonZero::new(3", stringify!($Int), ")?;")]
2110 ///
2111 /// assert_eq!(ten.isqrt(), three);
2112 /// # Some(())
2113 /// # }
2114 /// ```
2115 #[stable(feature = "isqrt", since = "1.84.0")]
2116 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
2117 #[must_use = "this returns the result of the operation, \
2118 without modifying the original"]
2119 #[inline]
2120 pub const fn isqrt(self) -> Self {
2121 let result = self.get().isqrt();
2122
2123 // SAFETY: Integer square root is a monotonically nondecreasing
2124 // function, which means that increasing the input will never cause
2125 // the output to decrease. Thus, since the input for nonzero
2126 // unsigned integers has a lower bound of 1, the lower bound of the
2127 // results will be sqrt(1), which is 1, so a result can't be zero.
2128 unsafe { Self::new_unchecked(result) }
2129 }
2130
2131 /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
2132 ///
2133 /// # Examples
2134 ///
2135 /// ```
2136 /// # use std::num::NonZero;
2137 ///
2138 #[doc = concat!("let n = NonZero::<", stringify!($Int), ">::MAX;")]
2139 ///
2140 #[doc = concat!("assert_eq!(n.cast_signed(), NonZero::new(-1", stringify!($Sint), ").unwrap());")]
2141 /// ```
2142 #[stable(feature = "integer_sign_cast", since = "1.87.0")]
2143 #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
2144 #[must_use = "this returns the result of the operation, \
2145 without modifying the original"]
2146 #[inline(always)]
2147 pub const fn cast_signed(self) -> NonZero<$Sint> {
2148 // SAFETY: `self.get()` can't be zero
2149 unsafe { NonZero::new_unchecked(self.get().cast_signed()) }
2150 }
2151
2152 /// Returns the minimum number of bits required to represent `self`.
2153 ///
2154 /// # Examples
2155 ///
2156 /// ```
2157 /// # use core::num::NonZero;
2158 /// #
2159 /// # fn main() { test().unwrap(); }
2160 /// # fn test() -> Option<()> {
2161 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1)?.bit_width(), NonZero::new(1)?);")]
2162 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b111)?.bit_width(), NonZero::new(3)?);")]
2163 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0b1110)?.bit_width(), NonZero::new(4)?);")]
2164 /// # Some(())
2165 /// # }
2166 /// ```
2167 #[stable(feature = "uint_bit_width", since = "1.97.0")]
2168 #[rustc_const_stable(feature = "uint_bit_width", since = "1.97.0")]
2169 #[must_use = "this returns the result of the operation, \
2170 without modifying the original"]
2171 #[inline(always)]
2172 pub const fn bit_width(self) -> NonZero<u32> {
2173 // SAFETY: Since `self.leading_zeros()` is always less than
2174 // `Self::BITS`, this subtraction can never be zero.
2175 unsafe { NonZero::new_unchecked(Self::BITS - self.leading_zeros()) }
2176 }
2177 };
2178
2179 // Associated items for signed nonzero types only.
2180 (
2181 Primitive = signed $Int:ident,
2182 SignedPrimitive = $Sint:ty,
2183 UnsignedPrimitive = $Uint:ty,
2184 ) => {
2185 /// The smallest value that can be represented by this non-zero
2186 /// integer type,
2187 #[doc = concat!("equal to [`", stringify!($Int), "::MIN`].")]
2188 ///
2189 /// Note: While most integer types are defined for every whole
2190 /// number between `MIN` and `MAX`, signed non-zero integers are
2191 /// a special case. They have a "gap" at 0.
2192 ///
2193 /// # Examples
2194 ///
2195 /// ```
2196 /// # use std::num::NonZero;
2197 /// #
2198 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::MIN.get(), ", stringify!($Int), "::MIN);")]
2199 /// ```
2200 #[stable(feature = "nonzero_min_max", since = "1.70.0")]
2201 pub const MIN: Self = Self::new(<$Int>::MIN).unwrap();
2202
2203 /// The largest value that can be represented by this non-zero
2204 /// integer type,
2205 #[doc = concat!("equal to [`", stringify!($Int), "::MAX`].")]
2206 ///
2207 /// Note: While most integer types are defined for every whole
2208 /// number between `MIN` and `MAX`, signed non-zero integers are
2209 /// a special case. They have a "gap" at 0.
2210 ///
2211 /// # Examples
2212 ///
2213 /// ```
2214 /// # use std::num::NonZero;
2215 /// #
2216 #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::MAX.get(), ", stringify!($Int), "::MAX);")]
2217 /// ```
2218 #[stable(feature = "nonzero_min_max", since = "1.70.0")]
2219 pub const MAX: Self = Self::new(<$Int>::MAX).unwrap();
2220
2221 /// Computes the absolute value of self.
2222 #[doc = concat!("See [`", stringify!($Int), "::abs`]")]
2223 /// for documentation on overflow behavior.
2224 ///
2225 /// # Example
2226 ///
2227 /// ```
2228 /// # use std::num::NonZero;
2229 /// #
2230 /// # fn main() { test().unwrap(); }
2231 /// # fn test() -> Option<()> {
2232 #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2233 #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2234 ///
2235 /// assert_eq!(pos, pos.abs());
2236 /// assert_eq!(pos, neg.abs());
2237 /// # Some(())
2238 /// # }
2239 /// ```
2240 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2241 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2242 #[must_use = "this returns the result of the operation, \
2243 without modifying the original"]
2244 #[inline]
2245 pub const fn abs(self) -> Self {
2246 // SAFETY: This cannot overflow to zero.
2247 unsafe { Self::new_unchecked(self.get().abs()) }
2248 }
2249
2250 /// Checked absolute value.
2251 /// Checks for overflow and returns [`None`] if
2252 #[doc = concat!("`self == NonZero::<", stringify!($Int), ">::MIN`.")]
2253 /// The result cannot be zero.
2254 ///
2255 /// # Example
2256 ///
2257 /// ```
2258 /// # use std::num::NonZero;
2259 /// #
2260 /// # fn main() { test().unwrap(); }
2261 /// # fn test() -> Option<()> {
2262 #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2263 #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2264 #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2265 ///
2266 /// assert_eq!(Some(pos), neg.checked_abs());
2267 /// assert_eq!(None, min.checked_abs());
2268 /// # Some(())
2269 /// # }
2270 /// ```
2271 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2272 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2273 #[must_use = "this returns the result of the operation, \
2274 without modifying the original"]
2275 #[inline]
2276 pub const fn checked_abs(self) -> Option<Self> {
2277 if let Some(nz) = self.get().checked_abs() {
2278 // SAFETY: absolute value of nonzero cannot yield zero values.
2279 Some(unsafe { Self::new_unchecked(nz) })
2280 } else {
2281 None
2282 }
2283 }
2284
2285 /// Computes the absolute value of self,
2286 /// with overflow information, see
2287 #[doc = concat!("[`", stringify!($Int), "::overflowing_abs`].")]
2288 ///
2289 /// # Example
2290 ///
2291 /// ```
2292 /// # use std::num::NonZero;
2293 /// #
2294 /// # fn main() { test().unwrap(); }
2295 /// # fn test() -> Option<()> {
2296 #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2297 #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2298 #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2299 ///
2300 /// assert_eq!((pos, false), pos.overflowing_abs());
2301 /// assert_eq!((pos, false), neg.overflowing_abs());
2302 /// assert_eq!((min, true), min.overflowing_abs());
2303 /// # Some(())
2304 /// # }
2305 /// ```
2306 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2307 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2308 #[must_use = "this returns the result of the operation, \
2309 without modifying the original"]
2310 #[inline]
2311 pub const fn overflowing_abs(self) -> (Self, bool) {
2312 let (nz, flag) = self.get().overflowing_abs();
2313 (
2314 // SAFETY: absolute value of nonzero cannot yield zero values.
2315 unsafe { Self::new_unchecked(nz) },
2316 flag,
2317 )
2318 }
2319
2320 /// Saturating absolute value, see
2321 #[doc = concat!("[`", stringify!($Int), "::saturating_abs`].")]
2322 ///
2323 /// # Example
2324 ///
2325 /// ```
2326 /// # use std::num::NonZero;
2327 /// #
2328 /// # fn main() { test().unwrap(); }
2329 /// # fn test() -> Option<()> {
2330 #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2331 #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2332 #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2333 #[doc = concat!("let min_plus = NonZero::new(", stringify!($Int), "::MIN + 1)?;")]
2334 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
2335 ///
2336 /// assert_eq!(pos, pos.saturating_abs());
2337 /// assert_eq!(pos, neg.saturating_abs());
2338 /// assert_eq!(max, min.saturating_abs());
2339 /// assert_eq!(max, min_plus.saturating_abs());
2340 /// # Some(())
2341 /// # }
2342 /// ```
2343 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2344 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2345 #[must_use = "this returns the result of the operation, \
2346 without modifying the original"]
2347 #[inline]
2348 pub const fn saturating_abs(self) -> Self {
2349 // SAFETY: absolute value of nonzero cannot yield zero values.
2350 unsafe { Self::new_unchecked(self.get().saturating_abs()) }
2351 }
2352
2353 /// Wrapping absolute value, see
2354 #[doc = concat!("[`", stringify!($Int), "::wrapping_abs`].")]
2355 ///
2356 /// # Example
2357 ///
2358 /// ```
2359 /// # use std::num::NonZero;
2360 /// #
2361 /// # fn main() { test().unwrap(); }
2362 /// # fn test() -> Option<()> {
2363 #[doc = concat!("let pos = NonZero::new(1", stringify!($Int), ")?;")]
2364 #[doc = concat!("let neg = NonZero::new(-1", stringify!($Int), ")?;")]
2365 #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2366 #[doc = concat!("# let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
2367 ///
2368 /// assert_eq!(pos, pos.wrapping_abs());
2369 /// assert_eq!(pos, neg.wrapping_abs());
2370 /// assert_eq!(min, min.wrapping_abs());
2371 /// assert_eq!(max, (-max).wrapping_abs());
2372 /// # Some(())
2373 /// # }
2374 /// ```
2375 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2376 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2377 #[must_use = "this returns the result of the operation, \
2378 without modifying the original"]
2379 #[inline]
2380 pub const fn wrapping_abs(self) -> Self {
2381 // SAFETY: absolute value of nonzero cannot yield zero values.
2382 unsafe { Self::new_unchecked(self.get().wrapping_abs()) }
2383 }
2384
2385 /// Computes the absolute value of self
2386 /// without any wrapping or panicking.
2387 ///
2388 /// # Example
2389 ///
2390 /// ```
2391 /// # use std::num::NonZero;
2392 /// #
2393 /// # fn main() { test().unwrap(); }
2394 /// # fn test() -> Option<()> {
2395 #[doc = concat!("let u_pos = NonZero::new(1", stringify!($Uint), ")?;")]
2396 #[doc = concat!("let i_pos = NonZero::new(1", stringify!($Int), ")?;")]
2397 #[doc = concat!("let i_neg = NonZero::new(-1", stringify!($Int), ")?;")]
2398 #[doc = concat!("let i_min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2399 #[doc = concat!("let u_max = NonZero::new(", stringify!($Uint), "::MAX / 2 + 1)?;")]
2400 ///
2401 /// assert_eq!(u_pos, i_pos.unsigned_abs());
2402 /// assert_eq!(u_pos, i_neg.unsigned_abs());
2403 /// assert_eq!(u_max, i_min.unsigned_abs());
2404 /// # Some(())
2405 /// # }
2406 /// ```
2407 #[stable(feature = "nonzero_checked_ops", since = "1.64.0")]
2408 #[rustc_const_stable(feature = "const_nonzero_checked_ops", since = "1.64.0")]
2409 #[must_use = "this returns the result of the operation, \
2410 without modifying the original"]
2411 #[inline]
2412 pub const fn unsigned_abs(self) -> NonZero<$Uint> {
2413 // SAFETY: absolute value of nonzero cannot yield zero values.
2414 unsafe { NonZero::new_unchecked(self.get().unsigned_abs()) }
2415 }
2416
2417 /// Returns `true` if `self` is positive and `false` if the
2418 /// number is negative.
2419 ///
2420 /// # Example
2421 ///
2422 /// ```
2423 /// # use std::num::NonZero;
2424 /// #
2425 /// # fn main() { test().unwrap(); }
2426 /// # fn test() -> Option<()> {
2427 #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2428 #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2429 ///
2430 /// assert!(pos_five.is_positive());
2431 /// assert!(!neg_five.is_positive());
2432 /// # Some(())
2433 /// # }
2434 /// ```
2435 #[must_use]
2436 #[inline]
2437 #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2438 #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2439 pub const fn is_positive(self) -> bool {
2440 self.get().is_positive()
2441 }
2442
2443 /// Returns `true` if `self` is negative and `false` if the
2444 /// number is positive.
2445 ///
2446 /// # Example
2447 ///
2448 /// ```
2449 /// # use std::num::NonZero;
2450 /// #
2451 /// # fn main() { test().unwrap(); }
2452 /// # fn test() -> Option<()> {
2453 #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2454 #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2455 ///
2456 /// assert!(neg_five.is_negative());
2457 /// assert!(!pos_five.is_negative());
2458 /// # Some(())
2459 /// # }
2460 /// ```
2461 #[must_use]
2462 #[inline]
2463 #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2464 #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2465 pub const fn is_negative(self) -> bool {
2466 self.get().is_negative()
2467 }
2468
2469 /// Checked negation. Computes `-self`,
2470 #[doc = concat!("returning `None` if `self == NonZero::<", stringify!($Int), ">::MIN`.")]
2471 ///
2472 /// # Example
2473 ///
2474 /// ```
2475 /// # use std::num::NonZero;
2476 /// #
2477 /// # fn main() { test().unwrap(); }
2478 /// # fn test() -> Option<()> {
2479 #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2480 #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2481 #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2482 ///
2483 /// assert_eq!(pos_five.checked_neg(), Some(neg_five));
2484 /// assert_eq!(min.checked_neg(), None);
2485 /// # Some(())
2486 /// # }
2487 /// ```
2488 #[inline]
2489 #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2490 #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2491 pub const fn checked_neg(self) -> Option<Self> {
2492 if let Some(result) = self.get().checked_neg() {
2493 // SAFETY: negation of nonzero cannot yield zero values.
2494 return Some(unsafe { Self::new_unchecked(result) });
2495 }
2496 None
2497 }
2498
2499 /// Negates self, overflowing if this is equal to the minimum value.
2500 ///
2501 #[doc = concat!("See [`", stringify!($Int), "::overflowing_neg`]")]
2502 /// for documentation on overflow behavior.
2503 ///
2504 /// # Example
2505 ///
2506 /// ```
2507 /// # use std::num::NonZero;
2508 /// #
2509 /// # fn main() { test().unwrap(); }
2510 /// # fn test() -> Option<()> {
2511 #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2512 #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2513 #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2514 ///
2515 /// assert_eq!(pos_five.overflowing_neg(), (neg_five, false));
2516 /// assert_eq!(min.overflowing_neg(), (min, true));
2517 /// # Some(())
2518 /// # }
2519 /// ```
2520 #[inline]
2521 #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2522 #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2523 pub const fn overflowing_neg(self) -> (Self, bool) {
2524 let (result, overflow) = self.get().overflowing_neg();
2525 // SAFETY: negation of nonzero cannot yield zero values.
2526 ((unsafe { Self::new_unchecked(result) }), overflow)
2527 }
2528
2529 /// Saturating negation. Computes `-self`,
2530 #[doc = concat!("returning [`NonZero::<", stringify!($Int), ">::MAX`]")]
2531 #[doc = concat!("if `self == NonZero::<", stringify!($Int), ">::MIN`")]
2532 /// instead of overflowing.
2533 ///
2534 /// # Example
2535 ///
2536 /// ```
2537 /// # use std::num::NonZero;
2538 /// #
2539 /// # fn main() { test().unwrap(); }
2540 /// # fn test() -> Option<()> {
2541 #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2542 #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2543 #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2544 #[doc = concat!("let min_plus_one = NonZero::new(", stringify!($Int), "::MIN + 1)?;")]
2545 #[doc = concat!("let max = NonZero::new(", stringify!($Int), "::MAX)?;")]
2546 ///
2547 /// assert_eq!(pos_five.saturating_neg(), neg_five);
2548 /// assert_eq!(min.saturating_neg(), max);
2549 /// assert_eq!(max.saturating_neg(), min_plus_one);
2550 /// # Some(())
2551 /// # }
2552 /// ```
2553 #[inline]
2554 #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2555 #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2556 pub const fn saturating_neg(self) -> Self {
2557 if let Some(result) = self.checked_neg() {
2558 return result;
2559 }
2560 Self::MAX
2561 }
2562
2563 /// Wrapping (modular) negation. Computes `-self`, wrapping around at the boundary
2564 /// of the type.
2565 ///
2566 #[doc = concat!("See [`", stringify!($Int), "::wrapping_neg`]")]
2567 /// for documentation on overflow behavior.
2568 ///
2569 /// # Example
2570 ///
2571 /// ```
2572 /// # use std::num::NonZero;
2573 /// #
2574 /// # fn main() { test().unwrap(); }
2575 /// # fn test() -> Option<()> {
2576 #[doc = concat!("let pos_five = NonZero::new(5", stringify!($Int), ")?;")]
2577 #[doc = concat!("let neg_five = NonZero::new(-5", stringify!($Int), ")?;")]
2578 #[doc = concat!("let min = NonZero::new(", stringify!($Int), "::MIN)?;")]
2579 ///
2580 /// assert_eq!(pos_five.wrapping_neg(), neg_five);
2581 /// assert_eq!(min.wrapping_neg(), min);
2582 /// # Some(())
2583 /// # }
2584 /// ```
2585 #[inline]
2586 #[stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2587 #[rustc_const_stable(feature = "nonzero_negation_ops", since = "1.71.0")]
2588 pub const fn wrapping_neg(self) -> Self {
2589 let result = self.get().wrapping_neg();
2590 // SAFETY: negation of nonzero cannot yield zero values.
2591 unsafe { Self::new_unchecked(result) }
2592 }
2593
2594 /// Returns the bit pattern of `self` reinterpreted as an unsigned integer of the same size.
2595 ///
2596 /// # Examples
2597 ///
2598 /// ```
2599 /// # use std::num::NonZero;
2600 ///
2601 #[doc = concat!("let n = NonZero::new(-1", stringify!($Int), ").unwrap();")]
2602 ///
2603 #[doc = concat!("assert_eq!(n.cast_unsigned(), NonZero::<", stringify!($Uint), ">::MAX);")]
2604 /// ```
2605 #[stable(feature = "integer_sign_cast", since = "1.87.0")]
2606 #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
2607 #[must_use = "this returns the result of the operation, \
2608 without modifying the original"]
2609 #[inline(always)]
2610 pub const fn cast_unsigned(self) -> NonZero<$Uint> {
2611 // SAFETY: `self.get()` can't be zero
2612 unsafe { NonZero::new_unchecked(self.get().cast_unsigned()) }
2613 }
2614
2615 };
2616}
2617
2618nonzero_integer! {
2619 Self = NonZeroU8,
2620 Primitive = unsigned u8,
2621 SignedPrimitive = i8,
2622 rot = 2,
2623 rot_op = "0x82",
2624 rot_result = "0xa",
2625 swap_op = "0x12",
2626 swapped = "0x12",
2627 reversed = "0x48",
2628}
2629
2630nonzero_integer! {
2631 Self = NonZeroU16,
2632 Primitive = unsigned u16,
2633 SignedPrimitive = i16,
2634 rot = 4,
2635 rot_op = "0xa003",
2636 rot_result = "0x3a",
2637 swap_op = "0x1234",
2638 swapped = "0x3412",
2639 reversed = "0x2c48",
2640}
2641
2642nonzero_integer! {
2643 Self = NonZeroU32,
2644 Primitive = unsigned u32,
2645 SignedPrimitive = i32,
2646 rot = 8,
2647 rot_op = "0x10000b3",
2648 rot_result = "0xb301",
2649 swap_op = "0x12345678",
2650 swapped = "0x78563412",
2651 reversed = "0x1e6a2c48",
2652}
2653
2654nonzero_integer! {
2655 Self = NonZeroU64,
2656 Primitive = unsigned u64,
2657 SignedPrimitive = i64,
2658 rot = 12,
2659 rot_op = "0xaa00000000006e1",
2660 rot_result = "0x6e10aa",
2661 swap_op = "0x1234567890123456",
2662 swapped = "0x5634129078563412",
2663 reversed = "0x6a2c48091e6a2c48",
2664}
2665
2666nonzero_integer! {
2667 Self = NonZeroU128,
2668 Primitive = unsigned u128,
2669 SignedPrimitive = i128,
2670 rot = 16,
2671 rot_op = "0x13f40000000000000000000000004f76",
2672 rot_result = "0x4f7613f4",
2673 swap_op = "0x12345678901234567890123456789012",
2674 swapped = "0x12907856341290785634129078563412",
2675 reversed = "0x48091e6a2c48091e6a2c48091e6a2c48",
2676}
2677
2678#[cfg(target_pointer_width = "16")]
2679nonzero_integer! {
2680 Self = NonZeroUsize,
2681 Primitive = unsigned usize,
2682 SignedPrimitive = isize,
2683 rot = 4,
2684 rot_op = "0xa003",
2685 rot_result = "0x3a",
2686 swap_op = "0x1234",
2687 swapped = "0x3412",
2688 reversed = "0x2c48",
2689}
2690
2691#[cfg(target_pointer_width = "32")]
2692nonzero_integer! {
2693 Self = NonZeroUsize,
2694 Primitive = unsigned usize,
2695 SignedPrimitive = isize,
2696 rot = 8,
2697 rot_op = "0x10000b3",
2698 rot_result = "0xb301",
2699 swap_op = "0x12345678",
2700 swapped = "0x78563412",
2701 reversed = "0x1e6a2c48",
2702}
2703
2704#[cfg(target_pointer_width = "64")]
2705nonzero_integer! {
2706 Self = NonZeroUsize,
2707 Primitive = unsigned usize,
2708 SignedPrimitive = isize,
2709 rot = 12,
2710 rot_op = "0xaa00000000006e1",
2711 rot_result = "0x6e10aa",
2712 swap_op = "0x1234567890123456",
2713 swapped = "0x5634129078563412",
2714 reversed = "0x6a2c48091e6a2c48",
2715}
2716
2717nonzero_integer! {
2718 Self = NonZeroI8,
2719 Primitive = signed i8,
2720 UnsignedPrimitive = u8,
2721 rot = 2,
2722 rot_op = "-0x7e",
2723 rot_result = "0xa",
2724 swap_op = "0x12",
2725 swapped = "0x12",
2726 reversed = "0x48",
2727}
2728
2729nonzero_integer! {
2730 Self = NonZeroI16,
2731 Primitive = signed i16,
2732 UnsignedPrimitive = u16,
2733 rot = 4,
2734 rot_op = "-0x5ffd",
2735 rot_result = "0x3a",
2736 swap_op = "0x1234",
2737 swapped = "0x3412",
2738 reversed = "0x2c48",
2739}
2740
2741nonzero_integer! {
2742 Self = NonZeroI32,
2743 Primitive = signed i32,
2744 UnsignedPrimitive = u32,
2745 rot = 8,
2746 rot_op = "0x10000b3",
2747 rot_result = "0xb301",
2748 swap_op = "0x12345678",
2749 swapped = "0x78563412",
2750 reversed = "0x1e6a2c48",
2751}
2752
2753nonzero_integer! {
2754 Self = NonZeroI64,
2755 Primitive = signed i64,
2756 UnsignedPrimitive = u64,
2757 rot = 12,
2758 rot_op = "0xaa00000000006e1",
2759 rot_result = "0x6e10aa",
2760 swap_op = "0x1234567890123456",
2761 swapped = "0x5634129078563412",
2762 reversed = "0x6a2c48091e6a2c48",
2763}
2764
2765nonzero_integer! {
2766 Self = NonZeroI128,
2767 Primitive = signed i128,
2768 UnsignedPrimitive = u128,
2769 rot = 16,
2770 rot_op = "0x13f40000000000000000000000004f76",
2771 rot_result = "0x4f7613f4",
2772 swap_op = "0x12345678901234567890123456789012",
2773 swapped = "0x12907856341290785634129078563412",
2774 reversed = "0x48091e6a2c48091e6a2c48091e6a2c48",
2775}
2776
2777#[cfg(target_pointer_width = "16")]
2778nonzero_integer! {
2779 Self = NonZeroIsize,
2780 Primitive = signed isize,
2781 UnsignedPrimitive = usize,
2782 rot = 4,
2783 rot_op = "-0x5ffd",
2784 rot_result = "0x3a",
2785 swap_op = "0x1234",
2786 swapped = "0x3412",
2787 reversed = "0x2c48",
2788}
2789
2790#[cfg(target_pointer_width = "32")]
2791nonzero_integer! {
2792 Self = NonZeroIsize,
2793 Primitive = signed isize,
2794 UnsignedPrimitive = usize,
2795 rot = 8,
2796 rot_op = "0x10000b3",
2797 rot_result = "0xb301",
2798 swap_op = "0x12345678",
2799 swapped = "0x78563412",
2800 reversed = "0x1e6a2c48",
2801}
2802
2803#[cfg(target_pointer_width = "64")]
2804nonzero_integer! {
2805 Self = NonZeroIsize,
2806 Primitive = signed isize,
2807 UnsignedPrimitive = usize,
2808 rot = 12,
2809 rot_op = "0xaa00000000006e1",
2810 rot_result = "0x6e10aa",
2811 swap_op = "0x1234567890123456",
2812 swapped = "0x5634129078563412",
2813 reversed = "0x6a2c48091e6a2c48",
2814}