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