core/num/
wrapping.rs

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1//! Definitions of `Wrapping<T>`.
2
3use crate::fmt;
4use crate::ops::{
5    Add, AddAssign, BitAnd, BitAndAssign, BitOr, BitOrAssign, BitXor, BitXorAssign, Div, DivAssign,
6    Mul, MulAssign, Neg, Not, Rem, RemAssign, Shl, ShlAssign, Shr, ShrAssign, Sub, SubAssign,
7};
8
9/// Provides intentionally-wrapped arithmetic on `T`.
10///
11/// Operations like `+` on `u32` values are intended to never overflow,
12/// and in some debug configurations overflow is detected and results
13/// in a panic. While most arithmetic falls into this category, some
14/// code explicitly expects and relies upon modular arithmetic (e.g.,
15/// hashing).
16///
17/// Wrapping arithmetic can be achieved either through methods like
18/// `wrapping_add`, or through the `Wrapping<T>` type, which says that
19/// all standard arithmetic operations on the underlying value are
20/// intended to have wrapping semantics.
21///
22/// The underlying value can be retrieved through the `.0` index of the
23/// `Wrapping` tuple.
24///
25/// # Examples
26///
27/// ```
28/// use std::num::Wrapping;
29///
30/// let zero = Wrapping(0u32);
31/// let one = Wrapping(1u32);
32///
33/// assert_eq!(u32::MAX, (zero - one).0);
34/// ```
35///
36/// # Layout
37///
38/// `Wrapping<T>` is guaranteed to have the same layout and ABI as `T`.
39#[stable(feature = "rust1", since = "1.0.0")]
40#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default, Hash)]
41#[repr(transparent)]
42#[rustc_diagnostic_item = "Wrapping"]
43pub struct Wrapping<T>(#[stable(feature = "rust1", since = "1.0.0")] pub T);
44
45#[stable(feature = "rust1", since = "1.0.0")]
46impl<T: fmt::Debug> fmt::Debug for Wrapping<T> {
47    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
48        self.0.fmt(f)
49    }
50}
51
52#[stable(feature = "wrapping_display", since = "1.10.0")]
53impl<T: fmt::Display> fmt::Display for Wrapping<T> {
54    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
55        self.0.fmt(f)
56    }
57}
58
59#[stable(feature = "wrapping_fmt", since = "1.11.0")]
60impl<T: fmt::Binary> fmt::Binary for Wrapping<T> {
61    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
62        self.0.fmt(f)
63    }
64}
65
66#[stable(feature = "wrapping_fmt", since = "1.11.0")]
67impl<T: fmt::Octal> fmt::Octal for Wrapping<T> {
68    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
69        self.0.fmt(f)
70    }
71}
72
73#[stable(feature = "wrapping_fmt", since = "1.11.0")]
74impl<T: fmt::LowerHex> fmt::LowerHex for Wrapping<T> {
75    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
76        self.0.fmt(f)
77    }
78}
79
80#[stable(feature = "wrapping_fmt", since = "1.11.0")]
81impl<T: fmt::UpperHex> fmt::UpperHex for Wrapping<T> {
82    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
83        self.0.fmt(f)
84    }
85}
86
87#[allow(unused_macros)]
88macro_rules! sh_impl_signed {
89    ($t:ident, $f:ident) => {
90        #[stable(feature = "rust1", since = "1.0.0")]
91        impl Shl<$f> for Wrapping<$t> {
92            type Output = Wrapping<$t>;
93
94            #[inline]
95            fn shl(self, other: $f) -> Wrapping<$t> {
96                if other < 0 {
97                    Wrapping(self.0.wrapping_shr((-other & self::shift_max::$t as $f) as u32))
98                } else {
99                    Wrapping(self.0.wrapping_shl((other & self::shift_max::$t as $f) as u32))
100                }
101            }
102        }
103        forward_ref_binop! { impl Shl, shl for Wrapping<$t>, $f,
104        #[stable(feature = "wrapping_ref_ops", since = "1.39.0")] }
105
106        #[stable(feature = "op_assign_traits", since = "1.8.0")]
107        impl ShlAssign<$f> for Wrapping<$t> {
108            #[inline]
109            fn shl_assign(&mut self, other: $f) {
110                *self = *self << other;
111            }
112        }
113        forward_ref_op_assign! { impl ShlAssign, shl_assign for Wrapping<$t>, $f }
114
115        #[stable(feature = "rust1", since = "1.0.0")]
116        impl Shr<$f> for Wrapping<$t> {
117            type Output = Wrapping<$t>;
118
119            #[inline]
120            fn shr(self, other: $f) -> Wrapping<$t> {
121                if other < 0 {
122                    Wrapping(self.0.wrapping_shl((-other & self::shift_max::$t as $f) as u32))
123                } else {
124                    Wrapping(self.0.wrapping_shr((other & self::shift_max::$t as $f) as u32))
125                }
126            }
127        }
128        forward_ref_binop! { impl Shr, shr for Wrapping<$t>, $f,
129        #[stable(feature = "wrapping_ref_ops", since = "1.39.0")] }
130
131        #[stable(feature = "op_assign_traits", since = "1.8.0")]
132        impl ShrAssign<$f> for Wrapping<$t> {
133            #[inline]
134            fn shr_assign(&mut self, other: $f) {
135                *self = *self >> other;
136            }
137        }
138        forward_ref_op_assign! { impl ShrAssign, shr_assign for Wrapping<$t>, $f }
139    };
140}
141
142macro_rules! sh_impl_unsigned {
143    ($t:ident, $f:ident) => {
144        #[stable(feature = "rust1", since = "1.0.0")]
145        impl Shl<$f> for Wrapping<$t> {
146            type Output = Wrapping<$t>;
147
148            #[inline]
149            fn shl(self, other: $f) -> Wrapping<$t> {
150                Wrapping(self.0.wrapping_shl((other & self::shift_max::$t as $f) as u32))
151            }
152        }
153        forward_ref_binop! { impl Shl, shl for Wrapping<$t>, $f,
154        #[stable(feature = "wrapping_ref_ops", since = "1.39.0")] }
155
156        #[stable(feature = "op_assign_traits", since = "1.8.0")]
157        impl ShlAssign<$f> for Wrapping<$t> {
158            #[inline]
159            fn shl_assign(&mut self, other: $f) {
160                *self = *self << other;
161            }
162        }
163        forward_ref_op_assign! { impl ShlAssign, shl_assign for Wrapping<$t>, $f }
164
165        #[stable(feature = "rust1", since = "1.0.0")]
166        impl Shr<$f> for Wrapping<$t> {
167            type Output = Wrapping<$t>;
168
169            #[inline]
170            fn shr(self, other: $f) -> Wrapping<$t> {
171                Wrapping(self.0.wrapping_shr((other & self::shift_max::$t as $f) as u32))
172            }
173        }
174        forward_ref_binop! { impl Shr, shr for Wrapping<$t>, $f,
175        #[stable(feature = "wrapping_ref_ops", since = "1.39.0")] }
176
177        #[stable(feature = "op_assign_traits", since = "1.8.0")]
178        impl ShrAssign<$f> for Wrapping<$t> {
179            #[inline]
180            fn shr_assign(&mut self, other: $f) {
181                *self = *self >> other;
182            }
183        }
184        forward_ref_op_assign! { impl ShrAssign, shr_assign for Wrapping<$t>, $f }
185    };
186}
187
188// FIXME (#23545): uncomment the remaining impls
189macro_rules! sh_impl_all {
190    ($($t:ident)*) => ($(
191        //sh_impl_unsigned! { $t, u8 }
192        //sh_impl_unsigned! { $t, u16 }
193        //sh_impl_unsigned! { $t, u32 }
194        //sh_impl_unsigned! { $t, u64 }
195        //sh_impl_unsigned! { $t, u128 }
196        sh_impl_unsigned! { $t, usize }
197
198        //sh_impl_signed! { $t, i8 }
199        //sh_impl_signed! { $t, i16 }
200        //sh_impl_signed! { $t, i32 }
201        //sh_impl_signed! { $t, i64 }
202        //sh_impl_signed! { $t, i128 }
203        //sh_impl_signed! { $t, isize }
204    )*)
205}
206
207sh_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize }
208
209// FIXME(30524): impl Op<T> for Wrapping<T>, impl OpAssign<T> for Wrapping<T>
210macro_rules! wrapping_impl {
211    ($($t:ty)*) => ($(
212        #[stable(feature = "rust1", since = "1.0.0")]
213        impl Add for Wrapping<$t> {
214            type Output = Wrapping<$t>;
215
216            #[inline]
217            fn add(self, other: Wrapping<$t>) -> Wrapping<$t> {
218                Wrapping(self.0.wrapping_add(other.0))
219            }
220        }
221        forward_ref_binop! { impl Add, add for Wrapping<$t>, Wrapping<$t>,
222                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
223
224        #[stable(feature = "op_assign_traits", since = "1.8.0")]
225        impl AddAssign for Wrapping<$t> {
226            #[inline]
227            fn add_assign(&mut self, other: Wrapping<$t>) {
228                *self = *self + other;
229            }
230        }
231        forward_ref_op_assign! { impl AddAssign, add_assign for Wrapping<$t>, Wrapping<$t> }
232
233        #[stable(feature = "wrapping_int_assign_impl", since = "1.60.0")]
234        impl AddAssign<$t> for Wrapping<$t> {
235            #[inline]
236            fn add_assign(&mut self, other: $t) {
237                *self = *self + Wrapping(other);
238            }
239        }
240        forward_ref_op_assign! { impl AddAssign, add_assign for Wrapping<$t>, $t }
241
242        #[stable(feature = "rust1", since = "1.0.0")]
243        impl Sub for Wrapping<$t> {
244            type Output = Wrapping<$t>;
245
246            #[inline]
247            fn sub(self, other: Wrapping<$t>) -> Wrapping<$t> {
248                Wrapping(self.0.wrapping_sub(other.0))
249            }
250        }
251        forward_ref_binop! { impl Sub, sub for Wrapping<$t>, Wrapping<$t>,
252                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
253
254        #[stable(feature = "op_assign_traits", since = "1.8.0")]
255        impl SubAssign for Wrapping<$t> {
256            #[inline]
257            fn sub_assign(&mut self, other: Wrapping<$t>) {
258                *self = *self - other;
259            }
260        }
261        forward_ref_op_assign! { impl SubAssign, sub_assign for Wrapping<$t>, Wrapping<$t> }
262
263        #[stable(feature = "wrapping_int_assign_impl", since = "1.60.0")]
264        impl SubAssign<$t> for Wrapping<$t> {
265            #[inline]
266            fn sub_assign(&mut self, other: $t) {
267                *self = *self - Wrapping(other);
268            }
269        }
270        forward_ref_op_assign! { impl SubAssign, sub_assign for Wrapping<$t>, $t }
271
272        #[stable(feature = "rust1", since = "1.0.0")]
273        impl Mul for Wrapping<$t> {
274            type Output = Wrapping<$t>;
275
276            #[inline]
277            fn mul(self, other: Wrapping<$t>) -> Wrapping<$t> {
278                Wrapping(self.0.wrapping_mul(other.0))
279            }
280        }
281        forward_ref_binop! { impl Mul, mul for Wrapping<$t>, Wrapping<$t>,
282                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
283
284        #[stable(feature = "op_assign_traits", since = "1.8.0")]
285        impl MulAssign for Wrapping<$t> {
286            #[inline]
287            fn mul_assign(&mut self, other: Wrapping<$t>) {
288                *self = *self * other;
289            }
290        }
291        forward_ref_op_assign! { impl MulAssign, mul_assign for Wrapping<$t>, Wrapping<$t> }
292
293        #[stable(feature = "wrapping_int_assign_impl", since = "1.60.0")]
294        impl MulAssign<$t> for Wrapping<$t> {
295            #[inline]
296            fn mul_assign(&mut self, other: $t) {
297                *self = *self * Wrapping(other);
298            }
299        }
300        forward_ref_op_assign! { impl MulAssign, mul_assign for Wrapping<$t>, $t }
301
302        #[stable(feature = "wrapping_div", since = "1.3.0")]
303        impl Div for Wrapping<$t> {
304            type Output = Wrapping<$t>;
305
306            #[inline]
307            fn div(self, other: Wrapping<$t>) -> Wrapping<$t> {
308                Wrapping(self.0.wrapping_div(other.0))
309            }
310        }
311        forward_ref_binop! { impl Div, div for Wrapping<$t>, Wrapping<$t>,
312                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
313
314        #[stable(feature = "op_assign_traits", since = "1.8.0")]
315        impl DivAssign for Wrapping<$t> {
316            #[inline]
317            fn div_assign(&mut self, other: Wrapping<$t>) {
318                *self = *self / other;
319            }
320        }
321        forward_ref_op_assign! { impl DivAssign, div_assign for Wrapping<$t>, Wrapping<$t> }
322
323        #[stable(feature = "wrapping_int_assign_impl", since = "1.60.0")]
324        impl DivAssign<$t> for Wrapping<$t> {
325            #[inline]
326            fn div_assign(&mut self, other: $t) {
327                *self = *self / Wrapping(other);
328            }
329        }
330        forward_ref_op_assign! { impl DivAssign, div_assign for Wrapping<$t>, $t }
331
332        #[stable(feature = "wrapping_impls", since = "1.7.0")]
333        impl Rem for Wrapping<$t> {
334            type Output = Wrapping<$t>;
335
336            #[inline]
337            fn rem(self, other: Wrapping<$t>) -> Wrapping<$t> {
338                Wrapping(self.0.wrapping_rem(other.0))
339            }
340        }
341        forward_ref_binop! { impl Rem, rem for Wrapping<$t>, Wrapping<$t>,
342                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
343
344        #[stable(feature = "op_assign_traits", since = "1.8.0")]
345        impl RemAssign for Wrapping<$t> {
346            #[inline]
347            fn rem_assign(&mut self, other: Wrapping<$t>) {
348                *self = *self % other;
349            }
350        }
351        forward_ref_op_assign! { impl RemAssign, rem_assign for Wrapping<$t>, Wrapping<$t> }
352
353        #[stable(feature = "wrapping_int_assign_impl", since = "1.60.0")]
354        impl RemAssign<$t> for Wrapping<$t> {
355            #[inline]
356            fn rem_assign(&mut self, other: $t) {
357                *self = *self % Wrapping(other);
358            }
359        }
360        forward_ref_op_assign! { impl RemAssign, rem_assign for Wrapping<$t>, $t }
361
362        #[stable(feature = "rust1", since = "1.0.0")]
363        impl Not for Wrapping<$t> {
364            type Output = Wrapping<$t>;
365
366            #[inline]
367            fn not(self) -> Wrapping<$t> {
368                Wrapping(!self.0)
369            }
370        }
371        forward_ref_unop! { impl Not, not for Wrapping<$t>,
372                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
373
374        #[stable(feature = "rust1", since = "1.0.0")]
375        impl BitXor for Wrapping<$t> {
376            type Output = Wrapping<$t>;
377
378            #[inline]
379            fn bitxor(self, other: Wrapping<$t>) -> Wrapping<$t> {
380                Wrapping(self.0 ^ other.0)
381            }
382        }
383        forward_ref_binop! { impl BitXor, bitxor for Wrapping<$t>, Wrapping<$t>,
384                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
385
386        #[stable(feature = "op_assign_traits", since = "1.8.0")]
387        impl BitXorAssign for Wrapping<$t> {
388            #[inline]
389            fn bitxor_assign(&mut self, other: Wrapping<$t>) {
390                *self = *self ^ other;
391            }
392        }
393        forward_ref_op_assign! { impl BitXorAssign, bitxor_assign for Wrapping<$t>, Wrapping<$t> }
394
395        #[stable(feature = "wrapping_int_assign_impl", since = "1.60.0")]
396        impl BitXorAssign<$t> for Wrapping<$t> {
397            #[inline]
398            fn bitxor_assign(&mut self, other: $t) {
399                *self = *self ^ Wrapping(other);
400            }
401        }
402        forward_ref_op_assign! { impl BitXorAssign, bitxor_assign for Wrapping<$t>, $t }
403
404        #[stable(feature = "rust1", since = "1.0.0")]
405        impl BitOr for Wrapping<$t> {
406            type Output = Wrapping<$t>;
407
408            #[inline]
409            fn bitor(self, other: Wrapping<$t>) -> Wrapping<$t> {
410                Wrapping(self.0 | other.0)
411            }
412        }
413        forward_ref_binop! { impl BitOr, bitor for Wrapping<$t>, Wrapping<$t>,
414                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
415
416        #[stable(feature = "op_assign_traits", since = "1.8.0")]
417        impl BitOrAssign for Wrapping<$t> {
418            #[inline]
419            fn bitor_assign(&mut self, other: Wrapping<$t>) {
420                *self = *self | other;
421            }
422        }
423        forward_ref_op_assign! { impl BitOrAssign, bitor_assign for Wrapping<$t>, Wrapping<$t> }
424
425        #[stable(feature = "wrapping_int_assign_impl", since = "1.60.0")]
426        impl BitOrAssign<$t> for Wrapping<$t> {
427            #[inline]
428            fn bitor_assign(&mut self, other: $t) {
429                *self = *self | Wrapping(other);
430            }
431        }
432        forward_ref_op_assign! { impl BitOrAssign, bitor_assign for Wrapping<$t>, $t }
433
434        #[stable(feature = "rust1", since = "1.0.0")]
435        impl BitAnd for Wrapping<$t> {
436            type Output = Wrapping<$t>;
437
438            #[inline]
439            fn bitand(self, other: Wrapping<$t>) -> Wrapping<$t> {
440                Wrapping(self.0 & other.0)
441            }
442        }
443        forward_ref_binop! { impl BitAnd, bitand for Wrapping<$t>, Wrapping<$t>,
444                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
445
446        #[stable(feature = "op_assign_traits", since = "1.8.0")]
447        impl BitAndAssign for Wrapping<$t> {
448            #[inline]
449            fn bitand_assign(&mut self, other: Wrapping<$t>) {
450                *self = *self & other;
451            }
452        }
453        forward_ref_op_assign! { impl BitAndAssign, bitand_assign for Wrapping<$t>, Wrapping<$t> }
454
455        #[stable(feature = "wrapping_int_assign_impl", since = "1.60.0")]
456        impl BitAndAssign<$t> for Wrapping<$t> {
457            #[inline]
458            fn bitand_assign(&mut self, other: $t) {
459                *self = *self & Wrapping(other);
460            }
461        }
462        forward_ref_op_assign! { impl BitAndAssign, bitand_assign for Wrapping<$t>, $t }
463
464        #[stable(feature = "wrapping_neg", since = "1.10.0")]
465        impl Neg for Wrapping<$t> {
466            type Output = Self;
467            #[inline]
468            fn neg(self) -> Self {
469                Wrapping(0) - self
470            }
471        }
472        forward_ref_unop! { impl Neg, neg for Wrapping<$t>,
473                #[stable(feature = "wrapping_ref", since = "1.14.0")] }
474
475    )*)
476}
477
478wrapping_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
479
480macro_rules! wrapping_int_impl {
481    ($($t:ty)*) => ($(
482        impl Wrapping<$t> {
483            /// Returns the smallest value that can be represented by this integer type.
484            ///
485            /// # Examples
486            ///
487            /// Basic usage:
488            ///
489            /// ```
490            /// #![feature(wrapping_int_impl)]
491            /// use std::num::Wrapping;
492            ///
493            #[doc = concat!("assert_eq!(<Wrapping<", stringify!($t), ">>::MIN, Wrapping(", stringify!($t), "::MIN));")]
494            /// ```
495            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
496            pub const MIN: Self = Self(<$t>::MIN);
497
498            /// Returns the largest value that can be represented by this integer type.
499            ///
500            /// # Examples
501            ///
502            /// Basic usage:
503            ///
504            /// ```
505            /// #![feature(wrapping_int_impl)]
506            /// use std::num::Wrapping;
507            ///
508            #[doc = concat!("assert_eq!(<Wrapping<", stringify!($t), ">>::MAX, Wrapping(", stringify!($t), "::MAX));")]
509            /// ```
510            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
511            pub const MAX: Self = Self(<$t>::MAX);
512
513            /// Returns the size of this integer type in bits.
514            ///
515            /// # Examples
516            ///
517            /// Basic usage:
518            ///
519            /// ```
520            /// #![feature(wrapping_int_impl)]
521            /// use std::num::Wrapping;
522            ///
523            #[doc = concat!("assert_eq!(<Wrapping<", stringify!($t), ">>::BITS, ", stringify!($t), "::BITS);")]
524            /// ```
525            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
526            pub const BITS: u32 = <$t>::BITS;
527
528            /// Returns the number of ones in the binary representation of `self`.
529            ///
530            /// # Examples
531            ///
532            /// Basic usage:
533            ///
534            /// ```
535            /// #![feature(wrapping_int_impl)]
536            /// use std::num::Wrapping;
537            ///
538            #[doc = concat!("let n = Wrapping(0b01001100", stringify!($t), ");")]
539            ///
540            /// assert_eq!(n.count_ones(), 3);
541            /// ```
542            #[inline]
543            #[doc(alias = "popcount")]
544            #[doc(alias = "popcnt")]
545            #[must_use = "this returns the result of the operation, \
546                          without modifying the original"]
547            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
548            pub const fn count_ones(self) -> u32 {
549                self.0.count_ones()
550            }
551
552            /// Returns the number of zeros in the binary representation of `self`.
553            ///
554            /// # Examples
555            ///
556            /// Basic usage:
557            ///
558            /// ```
559            /// #![feature(wrapping_int_impl)]
560            /// use std::num::Wrapping;
561            ///
562            #[doc = concat!("assert_eq!(Wrapping(!0", stringify!($t), ").count_zeros(), 0);")]
563            /// ```
564            #[inline]
565            #[must_use = "this returns the result of the operation, \
566                          without modifying the original"]
567            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
568            pub const fn count_zeros(self) -> u32 {
569                self.0.count_zeros()
570            }
571
572            /// Returns the number of trailing zeros in the binary representation of `self`.
573            ///
574            /// # Examples
575            ///
576            /// Basic usage:
577            ///
578            /// ```
579            /// #![feature(wrapping_int_impl)]
580            /// use std::num::Wrapping;
581            ///
582            #[doc = concat!("let n = Wrapping(0b0101000", stringify!($t), ");")]
583            ///
584            /// assert_eq!(n.trailing_zeros(), 3);
585            /// ```
586            #[inline]
587            #[must_use = "this returns the result of the operation, \
588                          without modifying the original"]
589            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
590            pub const fn trailing_zeros(self) -> u32 {
591                self.0.trailing_zeros()
592            }
593
594            /// Shifts the bits to the left by a specified amount, `n`,
595            /// wrapping the truncated bits to the end of the resulting
596            /// integer.
597            ///
598            /// Please note this isn't the same operation as the `<<` shifting
599            /// operator!
600            ///
601            /// # Examples
602            ///
603            /// Basic usage:
604            ///
605            /// ```
606            /// #![feature(wrapping_int_impl)]
607            /// use std::num::Wrapping;
608            ///
609            /// let n: Wrapping<i64> = Wrapping(0x0123456789ABCDEF);
610            /// let m: Wrapping<i64> = Wrapping(-0x76543210FEDCBA99);
611            ///
612            /// assert_eq!(n.rotate_left(32), m);
613            /// ```
614            #[inline]
615            #[must_use = "this returns the result of the operation, \
616                          without modifying the original"]
617            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
618            pub const fn rotate_left(self, n: u32) -> Self {
619                Wrapping(self.0.rotate_left(n))
620            }
621
622            /// Shifts the bits to the right by a specified amount, `n`,
623            /// wrapping the truncated bits to the beginning of the resulting
624            /// integer.
625            ///
626            /// Please note this isn't the same operation as the `>>` shifting
627            /// operator!
628            ///
629            /// # Examples
630            ///
631            /// Basic usage:
632            ///
633            /// ```
634            /// #![feature(wrapping_int_impl)]
635            /// use std::num::Wrapping;
636            ///
637            /// let n: Wrapping<i64> = Wrapping(0x0123456789ABCDEF);
638            /// let m: Wrapping<i64> = Wrapping(-0xFEDCBA987654322);
639            ///
640            /// assert_eq!(n.rotate_right(4), m);
641            /// ```
642            #[inline]
643            #[must_use = "this returns the result of the operation, \
644                          without modifying the original"]
645            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
646            pub const fn rotate_right(self, n: u32) -> Self {
647                Wrapping(self.0.rotate_right(n))
648            }
649
650            /// Reverses the byte order of the integer.
651            ///
652            /// # Examples
653            ///
654            /// Basic usage:
655            ///
656            /// ```
657            /// #![feature(wrapping_int_impl)]
658            /// use std::num::Wrapping;
659            ///
660            /// let n: Wrapping<i16> = Wrapping(0b0000000_01010101);
661            /// assert_eq!(n, Wrapping(85));
662            ///
663            /// let m = n.swap_bytes();
664            ///
665            /// assert_eq!(m, Wrapping(0b01010101_00000000));
666            /// assert_eq!(m, Wrapping(21760));
667            /// ```
668            #[inline]
669            #[must_use = "this returns the result of the operation, \
670                          without modifying the original"]
671            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
672            pub const fn swap_bytes(self) -> Self {
673                Wrapping(self.0.swap_bytes())
674            }
675
676            /// Reverses the bit pattern of the integer.
677            ///
678            /// # Examples
679            ///
680            /// Please note that this example is shared between integer types.
681            /// Which explains why `i16` is used here.
682            ///
683            /// Basic usage:
684            ///
685            /// ```
686            /// use std::num::Wrapping;
687            ///
688            /// let n = Wrapping(0b0000000_01010101i16);
689            /// assert_eq!(n, Wrapping(85));
690            ///
691            /// let m = n.reverse_bits();
692            ///
693            /// assert_eq!(m.0 as u16, 0b10101010_00000000);
694            /// assert_eq!(m, Wrapping(-22016));
695            /// ```
696            #[stable(feature = "reverse_bits", since = "1.37.0")]
697            #[rustc_const_stable(feature = "const_reverse_bits", since = "1.37.0")]
698            #[must_use = "this returns the result of the operation, \
699                          without modifying the original"]
700            #[inline]
701            pub const fn reverse_bits(self) -> Self {
702                Wrapping(self.0.reverse_bits())
703            }
704
705            /// Converts an integer from big endian to the target's endianness.
706            ///
707            /// On big endian this is a no-op. On little endian the bytes are
708            /// swapped.
709            ///
710            /// # Examples
711            ///
712            /// Basic usage:
713            ///
714            /// ```
715            /// #![feature(wrapping_int_impl)]
716            /// use std::num::Wrapping;
717            ///
718            #[doc = concat!("let n = Wrapping(0x1A", stringify!($t), ");")]
719            ///
720            /// if cfg!(target_endian = "big") {
721            #[doc = concat!("    assert_eq!(<Wrapping<", stringify!($t), ">>::from_be(n), n)")]
722            /// } else {
723            #[doc = concat!("    assert_eq!(<Wrapping<", stringify!($t), ">>::from_be(n), n.swap_bytes())")]
724            /// }
725            /// ```
726            #[inline]
727            #[must_use]
728            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
729            pub const fn from_be(x: Self) -> Self {
730                Wrapping(<$t>::from_be(x.0))
731            }
732
733            /// Converts an integer from little endian to the target's endianness.
734            ///
735            /// On little endian this is a no-op. On big endian the bytes are
736            /// swapped.
737            ///
738            /// # Examples
739            ///
740            /// Basic usage:
741            ///
742            /// ```
743            /// #![feature(wrapping_int_impl)]
744            /// use std::num::Wrapping;
745            ///
746            #[doc = concat!("let n = Wrapping(0x1A", stringify!($t), ");")]
747            ///
748            /// if cfg!(target_endian = "little") {
749            #[doc = concat!("    assert_eq!(<Wrapping<", stringify!($t), ">>::from_le(n), n)")]
750            /// } else {
751            #[doc = concat!("    assert_eq!(<Wrapping<", stringify!($t), ">>::from_le(n), n.swap_bytes())")]
752            /// }
753            /// ```
754            #[inline]
755            #[must_use]
756            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
757            pub const fn from_le(x: Self) -> Self {
758                Wrapping(<$t>::from_le(x.0))
759            }
760
761            /// Converts `self` to big endian from the target's endianness.
762            ///
763            /// On big endian this is a no-op. On little endian the bytes are
764            /// swapped.
765            ///
766            /// # Examples
767            ///
768            /// Basic usage:
769            ///
770            /// ```
771            /// #![feature(wrapping_int_impl)]
772            /// use std::num::Wrapping;
773            ///
774            #[doc = concat!("let n = Wrapping(0x1A", stringify!($t), ");")]
775            ///
776            /// if cfg!(target_endian = "big") {
777            ///     assert_eq!(n.to_be(), n)
778            /// } else {
779            ///     assert_eq!(n.to_be(), n.swap_bytes())
780            /// }
781            /// ```
782            #[inline]
783            #[must_use = "this returns the result of the operation, \
784                          without modifying the original"]
785            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
786            pub const fn to_be(self) -> Self {
787                Wrapping(self.0.to_be())
788            }
789
790            /// Converts `self` to little endian from the target's endianness.
791            ///
792            /// On little endian this is a no-op. On big endian the bytes are
793            /// swapped.
794            ///
795            /// # Examples
796            ///
797            /// Basic usage:
798            ///
799            /// ```
800            /// #![feature(wrapping_int_impl)]
801            /// use std::num::Wrapping;
802            ///
803            #[doc = concat!("let n = Wrapping(0x1A", stringify!($t), ");")]
804            ///
805            /// if cfg!(target_endian = "little") {
806            ///     assert_eq!(n.to_le(), n)
807            /// } else {
808            ///     assert_eq!(n.to_le(), n.swap_bytes())
809            /// }
810            /// ```
811            #[inline]
812            #[must_use = "this returns the result of the operation, \
813                          without modifying the original"]
814            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
815            pub const fn to_le(self) -> Self {
816                Wrapping(self.0.to_le())
817            }
818
819            /// Raises self to the power of `exp`, using exponentiation by squaring.
820            ///
821            /// # Examples
822            ///
823            /// Basic usage:
824            ///
825            /// ```
826            /// #![feature(wrapping_int_impl)]
827            /// use std::num::Wrapping;
828            ///
829            #[doc = concat!("assert_eq!(Wrapping(3", stringify!($t), ").pow(4), Wrapping(81));")]
830            /// ```
831            ///
832            /// Results that are too large are wrapped:
833            ///
834            /// ```
835            /// #![feature(wrapping_int_impl)]
836            /// use std::num::Wrapping;
837            ///
838            /// assert_eq!(Wrapping(3i8).pow(5), Wrapping(-13));
839            /// assert_eq!(Wrapping(3i8).pow(6), Wrapping(-39));
840            /// ```
841            #[inline]
842            #[must_use = "this returns the result of the operation, \
843                          without modifying the original"]
844            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
845            pub fn pow(self, exp: u32) -> Self {
846                Wrapping(self.0.wrapping_pow(exp))
847            }
848        }
849    )*)
850}
851
852wrapping_int_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }
853
854macro_rules! wrapping_int_impl_signed {
855    ($($t:ty)*) => ($(
856        impl Wrapping<$t> {
857            /// Returns the number of leading zeros in the binary representation of `self`.
858            ///
859            /// # Examples
860            ///
861            /// Basic usage:
862            ///
863            /// ```
864            /// #![feature(wrapping_int_impl)]
865            /// use std::num::Wrapping;
866            ///
867            #[doc = concat!("let n = Wrapping(", stringify!($t), "::MAX) >> 2;")]
868            ///
869            /// assert_eq!(n.leading_zeros(), 3);
870            /// ```
871            #[inline]
872            #[must_use = "this returns the result of the operation, \
873                          without modifying the original"]
874            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
875            pub const fn leading_zeros(self) -> u32 {
876                self.0.leading_zeros()
877            }
878
879            /// Computes the absolute value of `self`, wrapping around at
880            /// the boundary of the type.
881            ///
882            /// The only case where such wrapping can occur is when one takes the absolute value of the negative
883            /// minimal value for the type this is a positive value that is too large to represent in the type. In
884            /// such a case, this function returns `MIN` itself.
885            ///
886            /// # Examples
887            ///
888            /// Basic usage:
889            ///
890            /// ```
891            /// #![feature(wrapping_int_impl)]
892            /// use std::num::Wrapping;
893            ///
894            #[doc = concat!("assert_eq!(Wrapping(100", stringify!($t), ").abs(), Wrapping(100));")]
895            #[doc = concat!("assert_eq!(Wrapping(-100", stringify!($t), ").abs(), Wrapping(100));")]
896            #[doc = concat!("assert_eq!(Wrapping(", stringify!($t), "::MIN).abs(), Wrapping(", stringify!($t), "::MIN));")]
897            /// assert_eq!(Wrapping(-128i8).abs().0 as u8, 128u8);
898            /// ```
899            #[inline]
900            #[must_use = "this returns the result of the operation, \
901                          without modifying the original"]
902            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
903            pub fn abs(self) -> Wrapping<$t> {
904                Wrapping(self.0.wrapping_abs())
905            }
906
907            /// Returns a number representing sign of `self`.
908            ///
909            ///  - `0` if the number is zero
910            ///  - `1` if the number is positive
911            ///  - `-1` if the number is negative
912            ///
913            /// # Examples
914            ///
915            /// Basic usage:
916            ///
917            /// ```
918            /// #![feature(wrapping_int_impl)]
919            /// use std::num::Wrapping;
920            ///
921            #[doc = concat!("assert_eq!(Wrapping(10", stringify!($t), ").signum(), Wrapping(1));")]
922            #[doc = concat!("assert_eq!(Wrapping(0", stringify!($t), ").signum(), Wrapping(0));")]
923            #[doc = concat!("assert_eq!(Wrapping(-10", stringify!($t), ").signum(), Wrapping(-1));")]
924            /// ```
925            #[inline]
926            #[must_use = "this returns the result of the operation, \
927                          without modifying the original"]
928            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
929            pub fn signum(self) -> Wrapping<$t> {
930                Wrapping(self.0.signum())
931            }
932
933            /// Returns `true` if `self` is positive and `false` if the number is zero or
934            /// negative.
935            ///
936            /// # Examples
937            ///
938            /// Basic usage:
939            ///
940            /// ```
941            /// #![feature(wrapping_int_impl)]
942            /// use std::num::Wrapping;
943            ///
944            #[doc = concat!("assert!(Wrapping(10", stringify!($t), ").is_positive());")]
945            #[doc = concat!("assert!(!Wrapping(-10", stringify!($t), ").is_positive());")]
946            /// ```
947            #[must_use]
948            #[inline]
949            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
950            pub const fn is_positive(self) -> bool {
951                self.0.is_positive()
952            }
953
954            /// Returns `true` if `self` is negative and `false` if the number is zero or
955            /// positive.
956            ///
957            /// # Examples
958            ///
959            /// Basic usage:
960            ///
961            /// ```
962            /// #![feature(wrapping_int_impl)]
963            /// use std::num::Wrapping;
964            ///
965            #[doc = concat!("assert!(Wrapping(-10", stringify!($t), ").is_negative());")]
966            #[doc = concat!("assert!(!Wrapping(10", stringify!($t), ").is_negative());")]
967            /// ```
968            #[must_use]
969            #[inline]
970            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
971            pub const fn is_negative(self) -> bool {
972                self.0.is_negative()
973            }
974        }
975    )*)
976}
977
978wrapping_int_impl_signed! { isize i8 i16 i32 i64 i128 }
979
980macro_rules! wrapping_int_impl_unsigned {
981    ($($t:ty)*) => ($(
982        impl Wrapping<$t> {
983            /// Returns the number of leading zeros in the binary representation of `self`.
984            ///
985            /// # Examples
986            ///
987            /// Basic usage:
988            ///
989            /// ```
990            /// #![feature(wrapping_int_impl)]
991            /// use std::num::Wrapping;
992            ///
993            #[doc = concat!("let n = Wrapping(", stringify!($t), "::MAX) >> 2;")]
994            ///
995            /// assert_eq!(n.leading_zeros(), 2);
996            /// ```
997            #[inline]
998            #[must_use = "this returns the result of the operation, \
999                          without modifying the original"]
1000            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
1001            pub const fn leading_zeros(self) -> u32 {
1002                self.0.leading_zeros()
1003            }
1004
1005            /// Returns `true` if and only if `self == 2^k` for some `k`.
1006            ///
1007            /// # Examples
1008            ///
1009            /// Basic usage:
1010            ///
1011            /// ```
1012            /// #![feature(wrapping_int_impl)]
1013            /// use std::num::Wrapping;
1014            ///
1015            #[doc = concat!("assert!(Wrapping(16", stringify!($t), ").is_power_of_two());")]
1016            #[doc = concat!("assert!(!Wrapping(10", stringify!($t), ").is_power_of_two());")]
1017            /// ```
1018            #[must_use]
1019            #[inline]
1020            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
1021            pub fn is_power_of_two(self) -> bool {
1022                self.0.is_power_of_two()
1023            }
1024
1025            /// Returns the smallest power of two greater than or equal to `self`.
1026            ///
1027            /// When return value overflows (i.e., `self > (1 << (N-1))` for type
1028            /// `uN`), overflows to `2^N = 0`.
1029            ///
1030            /// # Examples
1031            ///
1032            /// Basic usage:
1033            ///
1034            /// ```
1035            /// #![feature(wrapping_next_power_of_two)]
1036            /// use std::num::Wrapping;
1037            ///
1038            #[doc = concat!("assert_eq!(Wrapping(2", stringify!($t), ").next_power_of_two(), Wrapping(2));")]
1039            #[doc = concat!("assert_eq!(Wrapping(3", stringify!($t), ").next_power_of_two(), Wrapping(4));")]
1040            #[doc = concat!("assert_eq!(Wrapping(200_u8).next_power_of_two(), Wrapping(0));")]
1041            /// ```
1042            #[inline]
1043            #[must_use = "this returns the result of the operation, \
1044                          without modifying the original"]
1045            #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
1046                       reason = "needs decision on wrapping behavior")]
1047            pub fn next_power_of_two(self) -> Self {
1048                Wrapping(self.0.wrapping_next_power_of_two())
1049            }
1050        }
1051    )*)
1052}
1053
1054wrapping_int_impl_unsigned! { usize u8 u16 u32 u64 u128 }
1055
1056mod shift_max {
1057    #![allow(non_upper_case_globals)]
1058
1059    #[cfg(target_pointer_width = "16")]
1060    mod platform {
1061        pub(crate) const usize: u32 = super::u16;
1062        pub(crate) const isize: u32 = super::i16;
1063    }
1064
1065    #[cfg(target_pointer_width = "32")]
1066    mod platform {
1067        pub(crate) const usize: u32 = super::u32;
1068        pub(crate) const isize: u32 = super::i32;
1069    }
1070
1071    #[cfg(target_pointer_width = "64")]
1072    mod platform {
1073        pub(crate) const usize: u32 = super::u64;
1074        pub(crate) const isize: u32 = super::i64;
1075    }
1076
1077    pub(super) const i8: u32 = (1 << 3) - 1;
1078    pub(super) const i16: u32 = (1 << 4) - 1;
1079    pub(super) const i32: u32 = (1 << 5) - 1;
1080    pub(super) const i64: u32 = (1 << 6) - 1;
1081    pub(super) const i128: u32 = (1 << 7) - 1;
1082    pub(super) use self::platform::isize;
1083
1084    pub(super) const u8: u32 = i8;
1085    pub(super) const u16: u32 = i16;
1086    pub(super) const u32: u32 = i32;
1087    pub(super) const u64: u32 = i64;
1088    pub(super) const u128: u32 = i128;
1089    pub(super) use self::platform::usize;
1090}
core/num/wrapping.rs

core/num/
wrapping.rs
