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core/num/
uint_macros.rs

1macro_rules! uint_impl {
2    (
3        Self = $SelfT:ty,
4        ActualT = $ActualT:ident,
5        SignedT = $SignedT:ident,
6
7        // These are all for use *only* in doc comments.
8        // As such, they're all passed as literals -- passing them as a string
9        // literal is fine if they need to be multiple code tokens.
10        // In non-comments, use the associated constants rather than these.
11        BITS = $BITS:literal,
12        BITS_MINUS_ONE = $BITS_MINUS_ONE:literal,
13        MAX = $MaxV:literal,
14        rot = $rot:literal,
15        rot_op = $rot_op:literal,
16        rot_result = $rot_result:literal,
17        fsh_op = $fsh_op:literal,
18        fshl_result = $fshl_result:literal,
19        fshr_result = $fshr_result:literal,
20        clmul_lhs = $clmul_lhs:literal,
21        clmul_rhs = $clmul_rhs:literal,
22        clmul_result = $clmul_result:literal,
23        swap_op = $swap_op:literal,
24        swapped = $swapped:literal,
25        reversed = $reversed:literal,
26        le_bytes = $le_bytes:literal,
27        be_bytes = $be_bytes:literal,
28        to_xe_bytes_doc = $to_xe_bytes_doc:expr,
29        from_xe_bytes_doc = $from_xe_bytes_doc:expr,
30        bound_condition = $bound_condition:literal,
31    ) => {
32        /// The smallest value that can be represented by this integer type.
33        ///
34        /// # Examples
35        ///
36        /// ```
37        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, 0);")]
38        /// ```
39        #[stable(feature = "assoc_int_consts", since = "1.43.0")]
40        pub const MIN: Self = 0;
41
42        /// The largest value that can be represented by this integer type
43        #[doc = concat!("(2<sup>", $BITS, "</sup> &minus; 1", $bound_condition, ").")]
44        ///
45        /// # Examples
46        ///
47        /// ```
48        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");")]
49        /// ```
50        #[stable(feature = "assoc_int_consts", since = "1.43.0")]
51        pub const MAX: Self = !0;
52
53        /// The size of this integer type in bits.
54        ///
55        /// # Examples
56        ///
57        /// ```
58        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
59        /// ```
60        #[stable(feature = "int_bits_const", since = "1.53.0")]
61        pub const BITS: u32 = Self::MAX.count_ones();
62
63        /// Returns the number of ones in the binary representation of `self`.
64        ///
65        /// # Examples
66        ///
67        /// ```
68        #[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")]
69        /// assert_eq!(n.count_ones(), 3);
70        ///
71        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
72        #[doc = concat!("assert_eq!(max.count_ones(), ", stringify!($BITS), ");")]
73        ///
74        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
75        /// assert_eq!(zero.count_ones(), 0);
76        /// ```
77        #[stable(feature = "rust1", since = "1.0.0")]
78        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
79        #[doc(alias = "popcount")]
80        #[doc(alias = "popcnt")]
81        #[must_use = "this returns the result of the operation, \
82                      without modifying the original"]
83        #[inline(always)]
84        pub const fn count_ones(self) -> u32 {
85            return intrinsics::ctpop(self);
86        }
87
88        /// Returns the number of zeros in the binary representation of `self`.
89        ///
90        /// # Examples
91        ///
92        /// ```
93        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
94        #[doc = concat!("assert_eq!(zero.count_zeros(), ", stringify!($BITS), ");")]
95        ///
96        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
97        /// assert_eq!(max.count_zeros(), 0);
98        /// ```
99        ///
100        /// This is heavily dependent on the width of the type, and thus
101        /// might give surprising results depending on type inference:
102        /// ```
103        /// # fn foo(_: u8) {}
104        /// # fn bar(_: u16) {}
105        /// let lucky = 7;
106        /// foo(lucky);
107        /// assert_eq!(lucky.count_zeros(), 5);
108        /// assert_eq!(lucky.count_ones(), 3);
109        ///
110        /// let lucky = 7;
111        /// bar(lucky);
112        /// assert_eq!(lucky.count_zeros(), 13);
113        /// assert_eq!(lucky.count_ones(), 3);
114        /// ```
115        /// You might want to use [`Self::count_ones`] instead, or emphasize
116        /// the type you're using in the call rather than method syntax:
117        /// ```
118        /// let small = 1;
119        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::count_zeros(small), ", stringify!($BITS_MINUS_ONE) ,");")]
120        /// ```
121        #[stable(feature = "rust1", since = "1.0.0")]
122        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
123        #[must_use = "this returns the result of the operation, \
124                      without modifying the original"]
125        #[inline(always)]
126        pub const fn count_zeros(self) -> u32 {
127            (!self).count_ones()
128        }
129
130        /// Returns the number of leading zeros in the binary representation of `self`.
131        ///
132        /// Depending on what you're doing with the value, you might also be interested in the
133        /// [`ilog2`] function which returns a consistent number, even if the type widens.
134        ///
135        /// # Examples
136        ///
137        /// ```
138        #[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")]
139        /// assert_eq!(n.leading_zeros(), 2);
140        ///
141        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
142        #[doc = concat!("assert_eq!(zero.leading_zeros(), ", stringify!($BITS), ");")]
143        ///
144        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
145        /// assert_eq!(max.leading_zeros(), 0);
146        /// ```
147        #[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")]
148        #[stable(feature = "rust1", since = "1.0.0")]
149        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
150        #[must_use = "this returns the result of the operation, \
151                      without modifying the original"]
152        #[inline(always)]
153        pub const fn leading_zeros(self) -> u32 {
154            return intrinsics::ctlz(self as $ActualT);
155        }
156
157        /// Returns the number of trailing zeros in the binary representation
158        /// of `self`.
159        ///
160        /// # Examples
161        ///
162        /// ```
163        #[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")]
164        /// assert_eq!(n.trailing_zeros(), 3);
165        ///
166        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
167        #[doc = concat!("assert_eq!(zero.trailing_zeros(), ", stringify!($BITS), ");")]
168        ///
169        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
170        #[doc = concat!("assert_eq!(max.trailing_zeros(), 0);")]
171        /// ```
172        #[stable(feature = "rust1", since = "1.0.0")]
173        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
174        #[must_use = "this returns the result of the operation, \
175                      without modifying the original"]
176        #[inline(always)]
177        pub const fn trailing_zeros(self) -> u32 {
178            return intrinsics::cttz(self);
179        }
180
181        /// Returns the number of leading ones in the binary representation of `self`.
182        ///
183        /// # Examples
184        ///
185        /// ```
186        #[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")]
187        /// assert_eq!(n.leading_ones(), 2);
188        ///
189        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
190        /// assert_eq!(zero.leading_ones(), 0);
191        ///
192        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
193        #[doc = concat!("assert_eq!(max.leading_ones(), ", stringify!($BITS), ");")]
194        /// ```
195        #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
196        #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
197        #[must_use = "this returns the result of the operation, \
198                      without modifying the original"]
199        #[inline(always)]
200        pub const fn leading_ones(self) -> u32 {
201            (!self).leading_zeros()
202        }
203
204        /// Returns the number of trailing ones in the binary representation
205        /// of `self`.
206        ///
207        /// # Examples
208        ///
209        /// ```
210        #[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")]
211        /// assert_eq!(n.trailing_ones(), 3);
212        ///
213        #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
214        /// assert_eq!(zero.trailing_ones(), 0);
215        ///
216        #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
217        #[doc = concat!("assert_eq!(max.trailing_ones(), ", stringify!($BITS), ");")]
218        /// ```
219        #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
220        #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
221        #[must_use = "this returns the result of the operation, \
222                      without modifying the original"]
223        #[inline(always)]
224        pub const fn trailing_ones(self) -> u32 {
225            (!self).trailing_zeros()
226        }
227
228        /// Returns the minimum number of bits required to represent `self`.
229        ///
230        /// This method returns zero if `self` is zero.
231        ///
232        /// # Examples
233        ///
234        /// ```
235        /// #![feature(uint_bit_width)]
236        ///
237        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".bit_width(), 0);")]
238        #[doc = concat!("assert_eq!(0b111_", stringify!($SelfT), ".bit_width(), 3);")]
239        #[doc = concat!("assert_eq!(0b1110_", stringify!($SelfT), ".bit_width(), 4);")]
240        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.bit_width(), ", stringify!($BITS), ");")]
241        /// ```
242        #[unstable(feature = "uint_bit_width", issue = "142326")]
243        #[must_use = "this returns the result of the operation, \
244                      without modifying the original"]
245        #[inline(always)]
246        pub const fn bit_width(self) -> u32 {
247            Self::BITS - self.leading_zeros()
248        }
249
250        /// Returns `self` with only the most significant bit set, or `0` if
251        /// the input is `0`.
252        ///
253        /// # Examples
254        ///
255        /// ```
256        /// #![feature(isolate_most_least_significant_one)]
257        ///
258        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
259        ///
260        /// assert_eq!(n.isolate_highest_one(), 0b_01000000);
261        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_highest_one(), 0);")]
262        /// ```
263        #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
264        #[must_use = "this returns the result of the operation, \
265                      without modifying the original"]
266        #[inline(always)]
267        pub const fn isolate_highest_one(self) -> Self {
268            self & (((1 as $SelfT) << (<$SelfT>::BITS - 1)).wrapping_shr(self.leading_zeros()))
269        }
270
271        /// Returns `self` with only the least significant bit set, or `0` if
272        /// the input is `0`.
273        ///
274        /// # Examples
275        ///
276        /// ```
277        /// #![feature(isolate_most_least_significant_one)]
278        ///
279        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
280        ///
281        /// assert_eq!(n.isolate_lowest_one(), 0b_00000100);
282        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_lowest_one(), 0);")]
283        /// ```
284        #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
285        #[must_use = "this returns the result of the operation, \
286                      without modifying the original"]
287        #[inline(always)]
288        pub const fn isolate_lowest_one(self) -> Self {
289            self & self.wrapping_neg()
290        }
291
292        /// Returns the index of the highest bit set to one in `self`, or `None`
293        /// if `self` is `0`.
294        ///
295        /// # Examples
296        ///
297        /// ```
298        /// #![feature(int_lowest_highest_one)]
299        ///
300        #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".highest_one(), None);")]
301        #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".highest_one(), Some(0));")]
302        #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".highest_one(), Some(4));")]
303        #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".highest_one(), Some(4));")]
304        /// ```
305        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
306        #[must_use = "this returns the result of the operation, \
307                      without modifying the original"]
308        #[inline(always)]
309        pub const fn highest_one(self) -> Option<u32> {
310            match NonZero::new(self) {
311                Some(v) => Some(v.highest_one()),
312                None => None,
313            }
314        }
315
316        /// Returns the index of the lowest bit set to one in `self`, or `None`
317        /// if `self` is `0`.
318        ///
319        /// # Examples
320        ///
321        /// ```
322        /// #![feature(int_lowest_highest_one)]
323        ///
324        #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".lowest_one(), None);")]
325        #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
326        #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".lowest_one(), Some(4));")]
327        #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".lowest_one(), Some(0));")]
328        /// ```
329        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
330        #[must_use = "this returns the result of the operation, \
331                      without modifying the original"]
332        #[inline(always)]
333        pub const fn lowest_one(self) -> Option<u32> {
334            match NonZero::new(self) {
335                Some(v) => Some(v.lowest_one()),
336                None => None,
337            }
338        }
339
340        /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
341        ///
342        /// This produces the same result as an `as` cast, but ensures that the bit-width remains
343        /// the same.
344        ///
345        /// # Examples
346        ///
347        /// ```
348        #[doc = concat!("let n = ", stringify!($SelfT), "::MAX;")]
349        ///
350        #[doc = concat!("assert_eq!(n.cast_signed(), -1", stringify!($SignedT), ");")]
351        /// ```
352        #[stable(feature = "integer_sign_cast", since = "1.87.0")]
353        #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
354        #[must_use = "this returns the result of the operation, \
355                      without modifying the original"]
356        #[inline(always)]
357        pub const fn cast_signed(self) -> $SignedT {
358            self as $SignedT
359        }
360
361        /// Shifts the bits to the left by a specified amount, `n`,
362        /// wrapping the truncated bits to the end of the resulting integer.
363        ///
364        /// `rotate_left(n)` is equivalent to applying `rotate_left(1)` a total of `n` times. In
365        /// particular, a rotation by the number of bits in `self` returns the input value
366        /// unchanged.
367        ///
368        /// Please note this isn't the same operation as the `<<` shifting operator!
369        ///
370        /// # Examples
371        ///
372        /// ```
373        #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
374        #[doc = concat!("let m = ", $rot_result, ";")]
375        ///
376        #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
377        #[doc = concat!("assert_eq!(n.rotate_left(1024), n);")]
378        /// ```
379        #[stable(feature = "rust1", since = "1.0.0")]
380        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
381        #[must_use = "this returns the result of the operation, \
382                      without modifying the original"]
383        #[inline(always)]
384        #[rustc_allow_const_fn_unstable(const_trait_impl)] // for the intrinsic fallback
385        pub const fn rotate_left(self, n: u32) -> Self {
386            return intrinsics::rotate_left(self, n);
387        }
388
389        /// Shifts the bits to the right by a specified amount, `n`,
390        /// wrapping the truncated bits to the beginning of the resulting
391        /// integer.
392        ///
393        /// `rotate_right(n)` is equivalent to applying `rotate_right(1)` a total of `n` times. In
394        /// particular, a rotation by the number of bits in `self` returns the input value
395        /// unchanged.
396        ///
397        /// Please note this isn't the same operation as the `>>` shifting operator!
398        ///
399        /// # Examples
400        ///
401        /// ```
402        #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
403        #[doc = concat!("let m = ", $rot_op, ";")]
404        ///
405        #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
406        #[doc = concat!("assert_eq!(n.rotate_right(1024), n);")]
407        /// ```
408        #[stable(feature = "rust1", since = "1.0.0")]
409        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
410        #[must_use = "this returns the result of the operation, \
411                      without modifying the original"]
412        #[inline(always)]
413        #[rustc_allow_const_fn_unstable(const_trait_impl)] // for the intrinsic fallback
414        pub const fn rotate_right(self, n: u32) -> Self {
415            return intrinsics::rotate_right(self, n);
416        }
417
418        /// Performs a left funnel shift (concatenates `self` with `rhs`, with `self`
419        /// making up the most significant half, then shifts the combined value left
420        /// by `n`, and most significant half is extracted to produce the result).
421        ///
422        /// Please note this isn't the same operation as the `<<` shifting operator or
423        /// [`rotate_left`](Self::rotate_left), although `a.funnel_shl(a, n)` is *equivalent*
424        /// to `a.rotate_left(n)`.
425        ///
426        /// # Panics
427        ///
428        /// If `n` is greater than or equal to the number of bits in `self`
429        ///
430        /// # Examples
431        ///
432        /// Basic usage:
433        ///
434        /// ```
435        /// #![feature(funnel_shifts)]
436        #[doc = concat!("let a = ", $rot_op, stringify!($SelfT), ";")]
437        #[doc = concat!("let b = ", $fsh_op, stringify!($SelfT), ";")]
438        #[doc = concat!("let m = ", $fshl_result, ";")]
439        ///
440        #[doc = concat!("assert_eq!(a.funnel_shl(b, ", $rot, "), m);")]
441        /// ```
442        #[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
443        #[unstable(feature = "funnel_shifts", issue = "145686")]
444        #[must_use = "this returns the result of the operation, \
445                      without modifying the original"]
446        #[inline(always)]
447        pub const fn funnel_shl(self, rhs: Self, n: u32) -> Self {
448            assert!(n < Self::BITS, "attempt to funnel shift left with overflow");
449            // SAFETY: just checked that `shift` is in-range
450            unsafe { intrinsics::unchecked_funnel_shl(self, rhs, n) }
451        }
452
453        /// Performs a right funnel shift (concatenates `self` and `rhs`, with `self`
454        /// making up the most significant half, then shifts the combined value right
455        /// by `n`, and least significant half is extracted to produce the result).
456        ///
457        /// Please note this isn't the same operation as the `>>` shifting operator or
458        /// [`rotate_right`](Self::rotate_right), although `a.funnel_shr(a, n)` is *equivalent*
459        /// to `a.rotate_right(n)`.
460        ///
461        /// # Panics
462        ///
463        /// If `n` is greater than or equal to the number of bits in `self`
464        ///
465        /// # Examples
466        ///
467        /// Basic usage:
468        ///
469        /// ```
470        /// #![feature(funnel_shifts)]
471        #[doc = concat!("let a = ", $rot_op, stringify!($SelfT), ";")]
472        #[doc = concat!("let b = ", $fsh_op, stringify!($SelfT), ";")]
473        #[doc = concat!("let m = ", $fshr_result, ";")]
474        ///
475        #[doc = concat!("assert_eq!(a.funnel_shr(b, ", $rot, "), m);")]
476        /// ```
477        #[rustc_const_unstable(feature = "funnel_shifts", issue = "145686")]
478        #[unstable(feature = "funnel_shifts", issue = "145686")]
479        #[must_use = "this returns the result of the operation, \
480                      without modifying the original"]
481        #[inline(always)]
482        pub const fn funnel_shr(self, rhs: Self, n: u32) -> Self {
483            assert!(n < Self::BITS, "attempt to funnel shift right with overflow");
484            // SAFETY: just checked that `shift` is in-range
485            unsafe { intrinsics::unchecked_funnel_shr(self, rhs, n) }
486        }
487
488        /// Performs a carry-less multiplication, returning the lower bits.
489        ///
490        /// This operation is similar to long multiplication in base 2, except that exclusive or is
491        /// used instead of addition. The implementation is equivalent to:
492        ///
493        /// ```no_run
494        #[doc = concat!("pub fn carryless_mul(lhs: ", stringify!($SelfT), ", rhs: ", stringify!($SelfT), ") -> ", stringify!($SelfT), "{")]
495        ///     let mut retval = 0;
496        #[doc = concat!("    for i in 0..",  stringify!($SelfT), "::BITS {")]
497        ///         if (rhs >> i) & 1 != 0 {
498        ///             // long multiplication would use +=
499        ///             retval ^= lhs << i;
500        ///         }
501        ///     }
502        ///     retval
503        /// }
504        /// ```
505        ///
506        /// The actual implementation is more efficient, and on some platforms lowers directly to a
507        /// dedicated instruction.
508        ///
509        /// # Uses
510        ///
511        /// Carryless multiplication can be used to turn a bitmask of quote characters into a
512        /// bit mask of characters surrounded by quotes:
513        ///
514        /// ```no_run
515        /// r#"abc xxx "foobar" zzz "a"!"#; // input string
516        ///  0b0000000010000001000001010; // quote_mask
517        ///  0b0000000001111110000000100; // quote_mask.carryless_mul(!0) & !quote_mask
518        /// ```
519        ///
520        /// Another use is in cryptography, where carryless multiplication allows for efficient
521        /// implementations of polynomial multiplication in `GF(2)[X]`, the polynomial ring
522        /// over `GF(2)`.
523        ///
524        /// # Examples
525        ///
526        /// ```
527        /// #![feature(uint_carryless_mul)]
528        ///
529        #[doc = concat!("let a = ", $clmul_lhs, stringify!($SelfT), ";")]
530        #[doc = concat!("let b = ", $clmul_rhs, stringify!($SelfT), ";")]
531        ///
532        #[doc = concat!("assert_eq!(a.carryless_mul(b), ", $clmul_result, ");")]
533        /// ```
534        #[rustc_const_unstable(feature = "uint_carryless_mul", issue = "152080")]
535        #[doc(alias = "clmul")]
536        #[unstable(feature = "uint_carryless_mul", issue = "152080")]
537        #[must_use = "this returns the result of the operation, \
538                      without modifying the original"]
539        #[inline(always)]
540        pub const fn carryless_mul(self, rhs: Self) -> Self {
541            intrinsics::carryless_mul(self, rhs)
542        }
543
544        /// Reverses the byte order of the integer.
545        ///
546        /// # Examples
547        ///
548        /// ```
549        #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
550        /// let m = n.swap_bytes();
551        ///
552        #[doc = concat!("assert_eq!(m, ", $swapped, ");")]
553        /// ```
554        #[stable(feature = "rust1", since = "1.0.0")]
555        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
556        #[must_use = "this returns the result of the operation, \
557                      without modifying the original"]
558        #[inline(always)]
559        pub const fn swap_bytes(self) -> Self {
560            intrinsics::bswap(self as $ActualT) as Self
561        }
562
563        /// Returns an integer with the bit locations specified by `mask` packed
564        /// contiguously into the least significant bits of the result.
565        /// ```
566        /// #![feature(uint_gather_scatter_bits)]
567        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b1011_1100;")]
568        ///
569        /// assert_eq!(n.extract_bits(0b0010_0100), 0b0000_0011);
570        /// assert_eq!(n.extract_bits(0xF0), 0b0000_1011);
571        /// ```
572        #[unstable(feature = "uint_gather_scatter_bits", issue = "149069")]
573        #[must_use = "this returns the result of the operation, \
574                      without modifying the original"]
575        #[inline]
576        pub const fn extract_bits(self, mask: Self) -> Self {
577            crate::num::int_bits::$ActualT::extract_impl(self as $ActualT, mask as $ActualT) as $SelfT
578        }
579
580        /// Returns an integer with the least significant bits of `self`
581        /// distributed to the bit locations specified by `mask`.
582        /// ```
583        /// #![feature(uint_gather_scatter_bits)]
584        #[doc = concat!("let n: ", stringify!($SelfT), " = 0b1010_1101;")]
585        ///
586        /// assert_eq!(n.deposit_bits(0b0101_0101), 0b0101_0001);
587        /// assert_eq!(n.deposit_bits(0xF0), 0b1101_0000);
588        /// ```
589        #[unstable(feature = "uint_gather_scatter_bits", issue = "149069")]
590        #[must_use = "this returns the result of the operation, \
591                      without modifying the original"]
592        #[inline]
593        pub const fn deposit_bits(self, mask: Self) -> Self {
594            crate::num::int_bits::$ActualT::deposit_impl(self as $ActualT, mask as $ActualT) as $SelfT
595        }
596
597        /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
598        ///                 second least-significant bit becomes second most-significant bit, etc.
599        ///
600        /// # Examples
601        ///
602        /// ```
603        #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
604        /// let m = n.reverse_bits();
605        ///
606        #[doc = concat!("assert_eq!(m, ", $reversed, ");")]
607        #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
608        /// ```
609        #[stable(feature = "reverse_bits", since = "1.37.0")]
610        #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
611        #[must_use = "this returns the result of the operation, \
612                      without modifying the original"]
613        #[inline(always)]
614        pub const fn reverse_bits(self) -> Self {
615            intrinsics::bitreverse(self as $ActualT) as Self
616        }
617
618        /// Converts an integer from big endian to the target's endianness.
619        ///
620        /// On big endian this is a no-op. On little endian the bytes are
621        /// swapped.
622        ///
623        /// # Examples
624        ///
625        /// ```
626        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
627        ///
628        /// if cfg!(target_endian = "big") {
629        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
630        /// } else {
631        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
632        /// }
633        /// ```
634        #[stable(feature = "rust1", since = "1.0.0")]
635        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
636        #[must_use]
637        #[inline(always)]
638        pub const fn from_be(x: Self) -> Self {
639            #[cfg(target_endian = "big")]
640            {
641                x
642            }
643            #[cfg(not(target_endian = "big"))]
644            {
645                x.swap_bytes()
646            }
647        }
648
649        /// Converts an integer from little endian to the target's endianness.
650        ///
651        /// On little endian this is a no-op. On big endian the bytes are
652        /// swapped.
653        ///
654        /// # Examples
655        ///
656        /// ```
657        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
658        ///
659        /// if cfg!(target_endian = "little") {
660        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
661        /// } else {
662        #[doc = concat!("    assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
663        /// }
664        /// ```
665        #[stable(feature = "rust1", since = "1.0.0")]
666        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
667        #[must_use]
668        #[inline(always)]
669        pub const fn from_le(x: Self) -> Self {
670            #[cfg(target_endian = "little")]
671            {
672                x
673            }
674            #[cfg(not(target_endian = "little"))]
675            {
676                x.swap_bytes()
677            }
678        }
679
680        /// Converts `self` to big endian from the target's endianness.
681        ///
682        /// On big endian this is a no-op. On little endian the bytes are
683        /// swapped.
684        ///
685        /// # Examples
686        ///
687        /// ```
688        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
689        ///
690        /// if cfg!(target_endian = "big") {
691        ///     assert_eq!(n.to_be(), n)
692        /// } else {
693        ///     assert_eq!(n.to_be(), n.swap_bytes())
694        /// }
695        /// ```
696        #[stable(feature = "rust1", since = "1.0.0")]
697        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
698        #[must_use = "this returns the result of the operation, \
699                      without modifying the original"]
700        #[inline(always)]
701        pub const fn to_be(self) -> Self { // or not to be?
702            #[cfg(target_endian = "big")]
703            {
704                self
705            }
706            #[cfg(not(target_endian = "big"))]
707            {
708                self.swap_bytes()
709            }
710        }
711
712        /// Converts `self` to little endian from the target's endianness.
713        ///
714        /// On little endian this is a no-op. On big endian the bytes are
715        /// swapped.
716        ///
717        /// # Examples
718        ///
719        /// ```
720        #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
721        ///
722        /// if cfg!(target_endian = "little") {
723        ///     assert_eq!(n.to_le(), n)
724        /// } else {
725        ///     assert_eq!(n.to_le(), n.swap_bytes())
726        /// }
727        /// ```
728        #[stable(feature = "rust1", since = "1.0.0")]
729        #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
730        #[must_use = "this returns the result of the operation, \
731                      without modifying the original"]
732        #[inline(always)]
733        pub const fn to_le(self) -> Self {
734            #[cfg(target_endian = "little")]
735            {
736                self
737            }
738            #[cfg(not(target_endian = "little"))]
739            {
740                self.swap_bytes()
741            }
742        }
743
744        /// Checked integer addition. Computes `self + rhs`, returning `None`
745        /// if overflow occurred.
746        ///
747        /// # Examples
748        ///
749        /// ```
750        #[doc = concat!(
751            "assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ",
752            "Some(", stringify!($SelfT), "::MAX - 1));"
753        )]
754        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
755        /// ```
756        #[stable(feature = "rust1", since = "1.0.0")]
757        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
758        #[must_use = "this returns the result of the operation, \
759                      without modifying the original"]
760        #[inline]
761        pub const fn checked_add(self, rhs: Self) -> Option<Self> {
762            // This used to use `overflowing_add`, but that means it ends up being
763            // a `wrapping_add`, losing some optimization opportunities. Notably,
764            // phrasing it this way helps `.checked_add(1)` optimize to a check
765            // against `MAX` and a `add nuw`.
766            // Per <https://github.com/rust-lang/rust/pull/124114#issuecomment-2066173305>,
767            // LLVM is happy to re-form the intrinsic later if useful.
768
769            if intrinsics::unlikely(intrinsics::add_with_overflow(self, rhs).1) {
770                None
771            } else {
772                // SAFETY: Just checked it doesn't overflow
773                Some(unsafe { intrinsics::unchecked_add(self, rhs) })
774            }
775        }
776
777        /// Strict integer addition. Computes `self + rhs`, panicking
778        /// if overflow occurred.
779        ///
780        /// # Panics
781        ///
782        /// ## Overflow behavior
783        ///
784        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
785        ///
786        /// # Examples
787        ///
788        /// ```
789        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
790        /// ```
791        ///
792        /// The following panics because of overflow:
793        ///
794        /// ```should_panic
795        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
796        /// ```
797        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
798        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
799        #[must_use = "this returns the result of the operation, \
800                      without modifying the original"]
801        #[inline]
802        #[track_caller]
803        pub const fn strict_add(self, rhs: Self) -> Self {
804            let (a, b) = self.overflowing_add(rhs);
805            if b { overflow_panic::add() } else { a }
806        }
807
808        /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
809        /// cannot occur.
810        ///
811        /// Calling `x.unchecked_add(y)` is semantically equivalent to calling
812        /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
813        ///
814        /// If you're just trying to avoid the panic in debug mode, then **do not**
815        /// use this.  Instead, you're looking for [`wrapping_add`].
816        ///
817        /// # Safety
818        ///
819        /// This results in undefined behavior when
820        #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
821        /// i.e. when [`checked_add`] would return `None`.
822        ///
823        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
824        #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
825        #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
826        #[stable(feature = "unchecked_math", since = "1.79.0")]
827        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
828        #[must_use = "this returns the result of the operation, \
829                      without modifying the original"]
830        #[inline(always)]
831        #[track_caller]
832        pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
833            assert_unsafe_precondition!(
834                check_language_ub,
835                concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
836                (
837                    lhs: $SelfT = self,
838                    rhs: $SelfT = rhs,
839                ) => !lhs.overflowing_add(rhs).1,
840            );
841
842            // SAFETY: this is guaranteed to be safe by the caller.
843            unsafe {
844                intrinsics::unchecked_add(self, rhs)
845            }
846        }
847
848        /// Checked addition with a signed integer. Computes `self + rhs`,
849        /// returning `None` if overflow occurred.
850        ///
851        /// # Examples
852        ///
853        /// ```
854        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
855        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
856        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")]
857        /// ```
858        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
859        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
860        #[must_use = "this returns the result of the operation, \
861                      without modifying the original"]
862        #[inline]
863        pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
864            let (a, b) = self.overflowing_add_signed(rhs);
865            if intrinsics::unlikely(b) { None } else { Some(a) }
866        }
867
868        /// Strict addition with a signed integer. Computes `self + rhs`,
869        /// panicking if overflow occurred.
870        ///
871        /// # Panics
872        ///
873        /// ## Overflow behavior
874        ///
875        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
876        ///
877        /// # Examples
878        ///
879        /// ```
880        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_signed(2), 3);")]
881        /// ```
882        ///
883        /// The following panic because of overflow:
884        ///
885        /// ```should_panic
886        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_add_signed(-2);")]
887        /// ```
888        ///
889        /// ```should_panic
890        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_signed(3);")]
891        /// ```
892        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
893        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
894        #[must_use = "this returns the result of the operation, \
895                      without modifying the original"]
896        #[inline]
897        #[track_caller]
898        pub const fn strict_add_signed(self, rhs: $SignedT) -> Self {
899            let (a, b) = self.overflowing_add_signed(rhs);
900            if b { overflow_panic::add() } else { a }
901        }
902
903        /// Checked integer subtraction. Computes `self - rhs`, returning
904        /// `None` if overflow occurred.
905        ///
906        /// # Examples
907        ///
908        /// ```
909        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")]
910        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")]
911        /// ```
912        #[stable(feature = "rust1", since = "1.0.0")]
913        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
914        #[must_use = "this returns the result of the operation, \
915                      without modifying the original"]
916        #[inline]
917        pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
918            // Per PR#103299, there's no advantage to the `overflowing` intrinsic
919            // for *unsigned* subtraction and we just emit the manual check anyway.
920            // Thus, rather than using `overflowing_sub` that produces a wrapping
921            // subtraction, check it ourself so we can use an unchecked one.
922
923            if self < rhs {
924                None
925            } else {
926                // SAFETY: just checked this can't overflow
927                Some(unsafe { intrinsics::unchecked_sub(self, rhs) })
928            }
929        }
930
931        /// Strict integer subtraction. Computes `self - rhs`, panicking if
932        /// overflow occurred.
933        ///
934        /// # Panics
935        ///
936        /// ## Overflow behavior
937        ///
938        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
939        ///
940        /// # Examples
941        ///
942        /// ```
943        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub(1), 0);")]
944        /// ```
945        ///
946        /// The following panics because of overflow:
947        ///
948        /// ```should_panic
949        #[doc = concat!("let _ = 0", stringify!($SelfT), ".strict_sub(1);")]
950        /// ```
951        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
952        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
953        #[must_use = "this returns the result of the operation, \
954                      without modifying the original"]
955        #[inline]
956        #[track_caller]
957        pub const fn strict_sub(self, rhs: Self) -> Self {
958            let (a, b) = self.overflowing_sub(rhs);
959            if b { overflow_panic::sub() } else { a }
960        }
961
962        /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
963        /// cannot occur.
964        ///
965        /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
966        /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
967        ///
968        /// If you're just trying to avoid the panic in debug mode, then **do not**
969        /// use this.  Instead, you're looking for [`wrapping_sub`].
970        ///
971        /// If you find yourself writing code like this:
972        ///
973        /// ```
974        /// # let foo = 30_u32;
975        /// # let bar = 20;
976        /// if foo >= bar {
977        ///     // SAFETY: just checked it will not overflow
978        ///     let diff = unsafe { foo.unchecked_sub(bar) };
979        ///     // ... use diff ...
980        /// }
981        /// ```
982        ///
983        /// Consider changing it to
984        ///
985        /// ```
986        /// # let foo = 30_u32;
987        /// # let bar = 20;
988        /// if let Some(diff) = foo.checked_sub(bar) {
989        ///     // ... use diff ...
990        /// }
991        /// ```
992        ///
993        /// As that does exactly the same thing -- including telling the optimizer
994        /// that the subtraction cannot overflow -- but avoids needing `unsafe`.
995        ///
996        /// # Safety
997        ///
998        /// This results in undefined behavior when
999        #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
1000        /// i.e. when [`checked_sub`] would return `None`.
1001        ///
1002        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
1003        #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
1004        #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
1005        #[stable(feature = "unchecked_math", since = "1.79.0")]
1006        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
1007        #[must_use = "this returns the result of the operation, \
1008                      without modifying the original"]
1009        #[inline(always)]
1010        #[track_caller]
1011        pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
1012            assert_unsafe_precondition!(
1013                check_language_ub,
1014                concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
1015                (
1016                    lhs: $SelfT = self,
1017                    rhs: $SelfT = rhs,
1018                ) => !lhs.overflowing_sub(rhs).1,
1019            );
1020
1021            // SAFETY: this is guaranteed to be safe by the caller.
1022            unsafe {
1023                intrinsics::unchecked_sub(self, rhs)
1024            }
1025        }
1026
1027        /// Checked subtraction with a signed integer. Computes `self - rhs`,
1028        /// returning `None` if overflow occurred.
1029        ///
1030        /// # Examples
1031        ///
1032        /// ```
1033        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(2), None);")]
1034        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(-2), Some(3));")]
1035        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_sub_signed(-4), None);")]
1036        /// ```
1037        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
1038        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
1039        #[must_use = "this returns the result of the operation, \
1040                      without modifying the original"]
1041        #[inline]
1042        pub const fn checked_sub_signed(self, rhs: $SignedT) -> Option<Self> {
1043            let (res, overflow) = self.overflowing_sub_signed(rhs);
1044
1045            if !overflow {
1046                Some(res)
1047            } else {
1048                None
1049            }
1050        }
1051
1052        /// Strict subtraction with a signed integer. Computes `self - rhs`,
1053        /// panicking if overflow occurred.
1054        ///
1055        /// # Panics
1056        ///
1057        /// ## Overflow behavior
1058        ///
1059        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1060        ///
1061        /// # Examples
1062        ///
1063        /// ```
1064        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".strict_sub_signed(2), 1);")]
1065        /// ```
1066        ///
1067        /// The following panic because of overflow:
1068        ///
1069        /// ```should_panic
1070        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_sub_signed(2);")]
1071        /// ```
1072        ///
1073        /// ```should_panic
1074        #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX).strict_sub_signed(-1);")]
1075        /// ```
1076        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1077        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1078        #[must_use = "this returns the result of the operation, \
1079                      without modifying the original"]
1080        #[inline]
1081        #[track_caller]
1082        pub const fn strict_sub_signed(self, rhs: $SignedT) -> Self {
1083            let (a, b) = self.overflowing_sub_signed(rhs);
1084            if b { overflow_panic::sub() } else { a }
1085        }
1086
1087        #[doc = concat!(
1088            "Checked integer subtraction. Computes `self - rhs` and checks if the result fits into an [`",
1089            stringify!($SignedT), "`], returning `None` if overflow occurred."
1090        )]
1091        ///
1092        /// # Examples
1093        ///
1094        /// ```
1095        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_signed_diff(2), Some(8));")]
1096        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_signed_diff(10), Some(-8));")]
1097        #[doc = concat!(
1098            "assert_eq!(",
1099            stringify!($SelfT),
1100            "::MAX.checked_signed_diff(",
1101            stringify!($SignedT),
1102            "::MAX as ",
1103            stringify!($SelfT),
1104            "), None);"
1105        )]
1106        #[doc = concat!(
1107            "assert_eq!((",
1108            stringify!($SignedT),
1109            "::MAX as ",
1110            stringify!($SelfT),
1111            ").checked_signed_diff(",
1112            stringify!($SelfT),
1113            "::MAX), Some(",
1114            stringify!($SignedT),
1115            "::MIN));"
1116        )]
1117        #[doc = concat!(
1118            "assert_eq!((",
1119            stringify!($SignedT),
1120            "::MAX as ",
1121            stringify!($SelfT),
1122            " + 1).checked_signed_diff(0), None);"
1123        )]
1124        #[doc = concat!(
1125            "assert_eq!(",
1126            stringify!($SelfT),
1127            "::MAX.checked_signed_diff(",
1128            stringify!($SelfT),
1129            "::MAX), Some(0));"
1130        )]
1131        /// ```
1132        #[stable(feature = "unsigned_signed_diff", since = "1.91.0")]
1133        #[rustc_const_stable(feature = "unsigned_signed_diff", since = "1.91.0")]
1134        #[inline]
1135        pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> {
1136            let res = self.wrapping_sub(rhs) as $SignedT;
1137            let overflow = (self >= rhs) == (res < 0);
1138
1139            if !overflow {
1140                Some(res)
1141            } else {
1142                None
1143            }
1144        }
1145
1146        /// Checked integer multiplication. Computes `self * rhs`, returning
1147        /// `None` if overflow occurred.
1148        ///
1149        /// # Examples
1150        ///
1151        /// ```
1152        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5));")]
1153        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
1154        /// ```
1155        #[stable(feature = "rust1", since = "1.0.0")]
1156        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1157        #[must_use = "this returns the result of the operation, \
1158                      without modifying the original"]
1159        #[inline]
1160        pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
1161            let (a, b) = self.overflowing_mul(rhs);
1162            if intrinsics::unlikely(b) { None } else { Some(a) }
1163        }
1164
1165        /// Strict integer multiplication. Computes `self * rhs`, panicking if
1166        /// overflow occurred.
1167        ///
1168        /// # Panics
1169        ///
1170        /// ## Overflow behavior
1171        ///
1172        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1173        ///
1174        /// # Examples
1175        ///
1176        /// ```
1177        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_mul(1), 5);")]
1178        /// ```
1179        ///
1180        /// The following panics because of overflow:
1181        ///
1182        /// ``` should_panic
1183        #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
1184        /// ```
1185        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1186        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1187        #[must_use = "this returns the result of the operation, \
1188                      without modifying the original"]
1189        #[inline]
1190        #[track_caller]
1191        pub const fn strict_mul(self, rhs: Self) -> Self {
1192            let (a, b) = self.overflowing_mul(rhs);
1193            if b { overflow_panic::mul() } else { a }
1194        }
1195
1196        /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
1197        /// cannot occur.
1198        ///
1199        /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
1200        /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
1201        ///
1202        /// If you're just trying to avoid the panic in debug mode, then **do not**
1203        /// use this.  Instead, you're looking for [`wrapping_mul`].
1204        ///
1205        /// # Safety
1206        ///
1207        /// This results in undefined behavior when
1208        #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
1209        /// i.e. when [`checked_mul`] would return `None`.
1210        ///
1211        /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
1212        #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
1213        #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
1214        #[stable(feature = "unchecked_math", since = "1.79.0")]
1215        #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
1216        #[must_use = "this returns the result of the operation, \
1217                      without modifying the original"]
1218        #[inline(always)]
1219        #[track_caller]
1220        pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
1221            assert_unsafe_precondition!(
1222                check_language_ub,
1223                concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
1224                (
1225                    lhs: $SelfT = self,
1226                    rhs: $SelfT = rhs,
1227                ) => !lhs.overflowing_mul(rhs).1,
1228            );
1229
1230            // SAFETY: this is guaranteed to be safe by the caller.
1231            unsafe {
1232                intrinsics::unchecked_mul(self, rhs)
1233            }
1234        }
1235
1236        /// Checked integer division. Computes `self / rhs`, returning `None`
1237        /// if `rhs == 0`.
1238        ///
1239        /// # Examples
1240        ///
1241        /// ```
1242        #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")]
1243        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")]
1244        /// ```
1245        #[stable(feature = "rust1", since = "1.0.0")]
1246        #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1247        #[must_use = "this returns the result of the operation, \
1248                      without modifying the original"]
1249        #[inline]
1250        pub const fn checked_div(self, rhs: Self) -> Option<Self> {
1251            if intrinsics::unlikely(rhs == 0) {
1252                None
1253            } else {
1254                // SAFETY: div by zero has been checked above and unsigned types have no other
1255                // failure modes for division
1256                Some(unsafe { intrinsics::unchecked_div(self, rhs) })
1257            }
1258        }
1259
1260        /// Strict integer division. Computes `self / rhs`.
1261        ///
1262        /// Strict division on unsigned types is just normal division. There's no
1263        /// way overflow could ever happen. This function exists so that all
1264        /// operations are accounted for in the strict operations.
1265        ///
1266        /// # Panics
1267        ///
1268        /// This function will panic if `rhs` is zero.
1269        ///
1270        /// # Examples
1271        ///
1272        /// ```
1273        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div(10), 10);")]
1274        /// ```
1275        ///
1276        /// The following panics because of division by zero:
1277        ///
1278        /// ```should_panic
1279        #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
1280        /// ```
1281        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1282        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1283        #[must_use = "this returns the result of the operation, \
1284                      without modifying the original"]
1285        #[inline(always)]
1286        #[track_caller]
1287        pub const fn strict_div(self, rhs: Self) -> Self {
1288            self / rhs
1289        }
1290
1291        /// Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None`
1292        /// if `rhs == 0`.
1293        ///
1294        /// # Examples
1295        ///
1296        /// ```
1297        #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")]
1298        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")]
1299        /// ```
1300        #[stable(feature = "euclidean_division", since = "1.38.0")]
1301        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1302        #[must_use = "this returns the result of the operation, \
1303                      without modifying the original"]
1304        #[inline]
1305        pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
1306            if intrinsics::unlikely(rhs == 0) {
1307                None
1308            } else {
1309                Some(self.div_euclid(rhs))
1310            }
1311        }
1312
1313        /// Strict Euclidean division. Computes `self.div_euclid(rhs)`.
1314        ///
1315        /// Strict division on unsigned types is just normal division. There's no
1316        /// way overflow could ever happen. This function exists so that all
1317        /// operations are accounted for in the strict operations. Since, for the
1318        /// positive integers, all common definitions of division are equal, this
1319        /// is exactly equal to `self.strict_div(rhs)`.
1320        ///
1321        /// # Panics
1322        ///
1323        /// This function will panic if `rhs` is zero.
1324        ///
1325        /// # Examples
1326        ///
1327        /// ```
1328        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div_euclid(10), 10);")]
1329        /// ```
1330        /// The following panics because of division by zero:
1331        ///
1332        /// ```should_panic
1333        #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
1334        /// ```
1335        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1336        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1337        #[must_use = "this returns the result of the operation, \
1338                      without modifying the original"]
1339        #[inline(always)]
1340        #[track_caller]
1341        pub const fn strict_div_euclid(self, rhs: Self) -> Self {
1342            self / rhs
1343        }
1344
1345        /// Checked integer division without remainder. Computes `self / rhs`,
1346        /// returning `None` if `rhs == 0` or if `self % rhs != 0`.
1347        ///
1348        /// # Examples
1349        ///
1350        /// ```
1351        /// #![feature(exact_div)]
1352        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(2), Some(32));")]
1353        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(32), Some(2));")]
1354        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_div_exact(0), None);")]
1355        #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".checked_div_exact(2), None);")]
1356        /// ```
1357        #[unstable(
1358            feature = "exact_div",
1359            issue = "139911",
1360        )]
1361        #[must_use = "this returns the result of the operation, \
1362                      without modifying the original"]
1363        #[inline]
1364        pub const fn checked_div_exact(self, rhs: Self) -> Option<Self> {
1365            if intrinsics::unlikely(rhs == 0) {
1366                None
1367            } else {
1368                // SAFETY: division by zero is checked above
1369                unsafe {
1370                    if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) {
1371                        None
1372                    } else {
1373                        Some(intrinsics::exact_div(self, rhs))
1374                    }
1375                }
1376            }
1377        }
1378
1379        /// Integer division without remainder. Computes `self / rhs`, returning `None` if `self % rhs != 0`.
1380        ///
1381        /// # Panics
1382        ///
1383        /// This function will panic  if `rhs == 0`.
1384        ///
1385        /// # Examples
1386        ///
1387        /// ```
1388        /// #![feature(exact_div)]
1389        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(2), Some(32));")]
1390        #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(32), Some(2));")]
1391        #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".div_exact(2), None);")]
1392        /// ```
1393        #[unstable(
1394            feature = "exact_div",
1395            issue = "139911",
1396        )]
1397        #[must_use = "this returns the result of the operation, \
1398                      without modifying the original"]
1399        #[inline]
1400        #[rustc_inherit_overflow_checks]
1401        pub const fn div_exact(self, rhs: Self) -> Option<Self> {
1402            if self % rhs != 0 {
1403                None
1404            } else {
1405                Some(self / rhs)
1406            }
1407        }
1408
1409        /// Unchecked integer division without remainder. Computes `self / rhs`.
1410        ///
1411        /// # Safety
1412        ///
1413        /// This results in undefined behavior when `rhs == 0` or `self % rhs != 0`,
1414        /// i.e. when [`checked_div_exact`](Self::checked_div_exact) would return `None`.
1415        #[unstable(
1416            feature = "exact_div",
1417            issue = "139911",
1418        )]
1419        #[must_use = "this returns the result of the operation, \
1420                      without modifying the original"]
1421        #[inline]
1422        pub const unsafe fn unchecked_div_exact(self, rhs: Self) -> Self {
1423            assert_unsafe_precondition!(
1424                check_language_ub,
1425                concat!(stringify!($SelfT), "::unchecked_div_exact divide by zero or leave a remainder"),
1426                (
1427                    lhs: $SelfT = self,
1428                    rhs: $SelfT = rhs,
1429                ) => rhs > 0 && lhs % rhs == 0,
1430            );
1431            // SAFETY: Same precondition
1432            unsafe { intrinsics::exact_div(self, rhs) }
1433        }
1434
1435        /// Checked integer remainder. Computes `self % rhs`, returning `None`
1436        /// if `rhs == 0`.
1437        ///
1438        /// # Examples
1439        ///
1440        /// ```
1441        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
1442        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
1443        /// ```
1444        #[stable(feature = "wrapping", since = "1.7.0")]
1445        #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1446        #[must_use = "this returns the result of the operation, \
1447                      without modifying the original"]
1448        #[inline]
1449        pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
1450            if intrinsics::unlikely(rhs == 0) {
1451                None
1452            } else {
1453                // SAFETY: div by zero has been checked above and unsigned types have no other
1454                // failure modes for division
1455                Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
1456            }
1457        }
1458
1459        /// Strict integer remainder. Computes `self % rhs`.
1460        ///
1461        /// Strict remainder calculation on unsigned types is just the regular
1462        /// remainder calculation. There's no way overflow could ever happen.
1463        /// This function exists so that all operations are accounted for in the
1464        /// strict operations.
1465        ///
1466        /// # Panics
1467        ///
1468        /// This function will panic if `rhs` is zero.
1469        ///
1470        /// # Examples
1471        ///
1472        /// ```
1473        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem(10), 0);")]
1474        /// ```
1475        ///
1476        /// The following panics because of division by zero:
1477        ///
1478        /// ```should_panic
1479        #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
1480        /// ```
1481        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1482        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1483        #[must_use = "this returns the result of the operation, \
1484                      without modifying the original"]
1485        #[inline(always)]
1486        #[track_caller]
1487        pub const fn strict_rem(self, rhs: Self) -> Self {
1488            self % rhs
1489        }
1490
1491        /// Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None`
1492        /// if `rhs == 0`.
1493        ///
1494        /// # Examples
1495        ///
1496        /// ```
1497        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
1498        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
1499        /// ```
1500        #[stable(feature = "euclidean_division", since = "1.38.0")]
1501        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1502        #[must_use = "this returns the result of the operation, \
1503                      without modifying the original"]
1504        #[inline]
1505        pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
1506            if intrinsics::unlikely(rhs == 0) {
1507                None
1508            } else {
1509                Some(self.rem_euclid(rhs))
1510            }
1511        }
1512
1513        /// Strict Euclidean modulo. Computes `self.rem_euclid(rhs)`.
1514        ///
1515        /// Strict modulo calculation on unsigned types is just the regular
1516        /// remainder calculation. There's no way overflow could ever happen.
1517        /// This function exists so that all operations are accounted for in the
1518        /// strict operations. Since, for the positive integers, all common
1519        /// definitions of division are equal, this is exactly equal to
1520        /// `self.strict_rem(rhs)`.
1521        ///
1522        /// # Panics
1523        ///
1524        /// This function will panic if `rhs` is zero.
1525        ///
1526        /// # Examples
1527        ///
1528        /// ```
1529        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem_euclid(10), 0);")]
1530        /// ```
1531        ///
1532        /// The following panics because of division by zero:
1533        ///
1534        /// ```should_panic
1535        #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
1536        /// ```
1537        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1538        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1539        #[must_use = "this returns the result of the operation, \
1540                      without modifying the original"]
1541        #[inline(always)]
1542        #[track_caller]
1543        pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
1544            self % rhs
1545        }
1546
1547        /// Same value as `self | other`, but UB if any bit position is set in both inputs.
1548        ///
1549        /// This is a situational micro-optimization for places where you'd rather
1550        /// use addition on some platforms and bitwise or on other platforms, based
1551        /// on exactly which instructions combine better with whatever else you're
1552        /// doing.  Note that there's no reason to bother using this for places
1553        /// where it's clear from the operations involved that they can't overlap.
1554        /// For example, if you're combining `u16`s into a `u32` with
1555        /// `((a as u32) << 16) | (b as u32)`, that's fine, as the backend will
1556        /// know those sides of the `|` are disjoint without needing help.
1557        ///
1558        /// # Examples
1559        ///
1560        /// ```
1561        /// #![feature(disjoint_bitor)]
1562        ///
1563        /// // SAFETY: `1` and `4` have no bits in common.
1564        /// unsafe {
1565        #[doc = concat!("    assert_eq!(1_", stringify!($SelfT), ".unchecked_disjoint_bitor(4), 5);")]
1566        /// }
1567        /// ```
1568        ///
1569        /// # Safety
1570        ///
1571        /// Requires that `(self & other) == 0`, otherwise it's immediate UB.
1572        ///
1573        /// Equivalently, requires that `(self | other) == (self + other)`.
1574        #[unstable(feature = "disjoint_bitor", issue = "135758")]
1575        #[rustc_const_unstable(feature = "disjoint_bitor", issue = "135758")]
1576        #[inline]
1577        pub const unsafe fn unchecked_disjoint_bitor(self, other: Self) -> Self {
1578            assert_unsafe_precondition!(
1579                check_language_ub,
1580                concat!(stringify!($SelfT), "::unchecked_disjoint_bitor cannot have overlapping bits"),
1581                (
1582                    lhs: $SelfT = self,
1583                    rhs: $SelfT = other,
1584                ) => (lhs & rhs) == 0,
1585            );
1586
1587            // SAFETY: Same precondition
1588            unsafe { intrinsics::disjoint_bitor(self, other) }
1589        }
1590
1591        /// Returns the logarithm of the number with respect to an arbitrary base,
1592        /// rounded down.
1593        ///
1594        /// This method might not be optimized owing to implementation details;
1595        /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
1596        /// can produce results more efficiently for base 10.
1597        ///
1598        /// # Panics
1599        ///
1600        /// This function will panic if `self` is zero, or if `base` is less than 2.
1601        ///
1602        /// # Examples
1603        ///
1604        /// ```
1605        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
1606        /// ```
1607        #[stable(feature = "int_log", since = "1.67.0")]
1608        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1609        #[must_use = "this returns the result of the operation, \
1610                      without modifying the original"]
1611        #[inline]
1612        #[track_caller]
1613        pub const fn ilog(self, base: Self) -> u32 {
1614            assert!(base >= 2, "base of integer logarithm must be at least 2");
1615            if let Some(log) = self.checked_ilog(base) {
1616                log
1617            } else {
1618                int_log10::panic_for_nonpositive_argument()
1619            }
1620        }
1621
1622        /// Returns the base 2 logarithm of the number, rounded down.
1623        ///
1624        /// # Panics
1625        ///
1626        /// This function will panic if `self` is zero.
1627        ///
1628        /// # Examples
1629        ///
1630        /// ```
1631        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
1632        /// ```
1633        #[stable(feature = "int_log", since = "1.67.0")]
1634        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1635        #[must_use = "this returns the result of the operation, \
1636                      without modifying the original"]
1637        #[inline]
1638        #[track_caller]
1639        pub const fn ilog2(self) -> u32 {
1640            if let Some(log) = self.checked_ilog2() {
1641                log
1642            } else {
1643                int_log10::panic_for_nonpositive_argument()
1644            }
1645        }
1646
1647        /// Returns the base 10 logarithm of the number, rounded down.
1648        ///
1649        /// # Panics
1650        ///
1651        /// This function will panic if `self` is zero.
1652        ///
1653        /// # Example
1654        ///
1655        /// ```
1656        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
1657        /// ```
1658        #[stable(feature = "int_log", since = "1.67.0")]
1659        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1660        #[must_use = "this returns the result of the operation, \
1661                      without modifying the original"]
1662        #[inline]
1663        #[track_caller]
1664        pub const fn ilog10(self) -> u32 {
1665            if let Some(log) = self.checked_ilog10() {
1666                log
1667            } else {
1668                int_log10::panic_for_nonpositive_argument()
1669            }
1670        }
1671
1672        /// Returns the logarithm of the number with respect to an arbitrary base,
1673        /// rounded down.
1674        ///
1675        /// Returns `None` if the number is zero, or if the base is not at least 2.
1676        ///
1677        /// This method might not be optimized owing to implementation details;
1678        /// `checked_ilog2` can produce results more efficiently for base 2, and
1679        /// `checked_ilog10` can produce results more efficiently for base 10.
1680        ///
1681        /// # Examples
1682        ///
1683        /// ```
1684        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
1685        /// ```
1686        #[stable(feature = "int_log", since = "1.67.0")]
1687        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1688        #[must_use = "this returns the result of the operation, \
1689                      without modifying the original"]
1690        #[inline]
1691        pub const fn checked_ilog(self, base: Self) -> Option<u32> {
1692            // Inform compiler of optimizations when the base is known at
1693            // compile time and there's a cheaper method available.
1694            //
1695            // Note: Like all optimizations, this is not guaranteed to be
1696            // applied by the compiler. If you want those specific bases,
1697            // use `.checked_ilog2()` or `.checked_ilog10()` directly.
1698            if core::intrinsics::is_val_statically_known(base) {
1699                if base == 2 {
1700                    return self.checked_ilog2();
1701                } else if base == 10 {
1702                    return self.checked_ilog10();
1703                }
1704            }
1705
1706            if self <= 0 || base <= 1 {
1707                None
1708            } else if self < base {
1709                Some(0)
1710            } else {
1711                // Since base >= self, n >= 1
1712                let mut n = 1;
1713                let mut r = base;
1714
1715                // Optimization for 128 bit wide integers.
1716                if Self::BITS == 128 {
1717                    // The following is a correct lower bound for ⌊log(base,self)⌋ because
1718                    //
1719                    // log(base,self) = log(2,self) / log(2,base)
1720                    //                ≥ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1)
1721                    //
1722                    // hence
1723                    //
1724                    // ⌊log(base,self)⌋ ≥ ⌊ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1) ⌋ .
1725                    n = self.ilog2() / (base.ilog2() + 1);
1726                    r = base.pow(n);
1727                }
1728
1729                while r <= self / base {
1730                    n += 1;
1731                    r *= base;
1732                }
1733                Some(n)
1734            }
1735        }
1736
1737        /// Returns the base 2 logarithm of the number, rounded down.
1738        ///
1739        /// Returns `None` if the number is zero.
1740        ///
1741        /// # Examples
1742        ///
1743        /// ```
1744        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
1745        /// ```
1746        #[stable(feature = "int_log", since = "1.67.0")]
1747        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1748        #[must_use = "this returns the result of the operation, \
1749                      without modifying the original"]
1750        #[inline]
1751        pub const fn checked_ilog2(self) -> Option<u32> {
1752            match NonZero::new(self) {
1753                Some(x) => Some(x.ilog2()),
1754                None => None,
1755            }
1756        }
1757
1758        /// Returns the base 10 logarithm of the number, rounded down.
1759        ///
1760        /// Returns `None` if the number is zero.
1761        ///
1762        /// # Examples
1763        ///
1764        /// ```
1765        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
1766        /// ```
1767        #[stable(feature = "int_log", since = "1.67.0")]
1768        #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1769        #[must_use = "this returns the result of the operation, \
1770                      without modifying the original"]
1771        #[inline]
1772        pub const fn checked_ilog10(self) -> Option<u32> {
1773            match NonZero::new(self) {
1774                Some(x) => Some(x.ilog10()),
1775                None => None,
1776            }
1777        }
1778
1779        /// Checked negation. Computes `-self`, returning `None` unless `self ==
1780        /// 0`.
1781        ///
1782        /// Note that negating any positive integer will overflow.
1783        ///
1784        /// # Examples
1785        ///
1786        /// ```
1787        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")]
1788        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")]
1789        /// ```
1790        #[stable(feature = "wrapping", since = "1.7.0")]
1791        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1792        #[must_use = "this returns the result of the operation, \
1793                      without modifying the original"]
1794        #[inline]
1795        pub const fn checked_neg(self) -> Option<Self> {
1796            let (a, b) = self.overflowing_neg();
1797            if intrinsics::unlikely(b) { None } else { Some(a) }
1798        }
1799
1800        /// Strict negation. Computes `-self`, panicking unless `self ==
1801        /// 0`.
1802        ///
1803        /// Note that negating any positive integer will overflow.
1804        ///
1805        /// # Panics
1806        ///
1807        /// ## Overflow behavior
1808        ///
1809        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1810        ///
1811        /// # Examples
1812        ///
1813        /// ```
1814        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".strict_neg(), 0);")]
1815        /// ```
1816        ///
1817        /// The following panics because of overflow:
1818        ///
1819        /// ```should_panic
1820        #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_neg();")]
1821        /// ```
1822        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1823        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1824        #[must_use = "this returns the result of the operation, \
1825                      without modifying the original"]
1826        #[inline]
1827        #[track_caller]
1828        pub const fn strict_neg(self) -> Self {
1829            let (a, b) = self.overflowing_neg();
1830            if b { overflow_panic::neg() } else { a }
1831        }
1832
1833        /// Checked shift left. Computes `self << rhs`, returning `None`
1834        /// if `rhs` is larger than or equal to the number of bits in `self`.
1835        ///
1836        /// # Examples
1837        ///
1838        /// ```
1839        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
1840        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")]
1841        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
1842        /// ```
1843        #[stable(feature = "wrapping", since = "1.7.0")]
1844        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1845        #[must_use = "this returns the result of the operation, \
1846                      without modifying the original"]
1847        #[inline]
1848        pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
1849            // Not using overflowing_shl as that's a wrapping shift
1850            if rhs < Self::BITS {
1851                // SAFETY: just checked the RHS is in-range
1852                Some(unsafe { self.unchecked_shl(rhs) })
1853            } else {
1854                None
1855            }
1856        }
1857
1858        /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
1859        /// than or equal to the number of bits in `self`.
1860        ///
1861        /// # Panics
1862        ///
1863        /// ## Overflow behavior
1864        ///
1865        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1866        ///
1867        /// # Examples
1868        ///
1869        /// ```
1870        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
1871        /// ```
1872        ///
1873        /// The following panics because of overflow:
1874        ///
1875        /// ```should_panic
1876        #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shl(129);")]
1877        /// ```
1878        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1879        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1880        #[must_use = "this returns the result of the operation, \
1881                      without modifying the original"]
1882        #[inline]
1883        #[track_caller]
1884        pub const fn strict_shl(self, rhs: u32) -> Self {
1885            let (a, b) = self.overflowing_shl(rhs);
1886            if b { overflow_panic::shl() } else { a }
1887        }
1888
1889        /// Unchecked shift left. Computes `self << rhs`, assuming that
1890        /// `rhs` is less than the number of bits in `self`.
1891        ///
1892        /// # Safety
1893        ///
1894        /// This results in undefined behavior if `rhs` is larger than
1895        /// or equal to the number of bits in `self`,
1896        /// i.e. when [`checked_shl`] would return `None`.
1897        ///
1898        #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
1899        #[stable(feature = "unchecked_shifts", since = "1.93.0")]
1900        #[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
1901        #[must_use = "this returns the result of the operation, \
1902                      without modifying the original"]
1903        #[inline(always)]
1904        #[track_caller]
1905        pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
1906            assert_unsafe_precondition!(
1907                check_language_ub,
1908                concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
1909                (
1910                    rhs: u32 = rhs,
1911                ) => rhs < <$ActualT>::BITS,
1912            );
1913
1914            // SAFETY: this is guaranteed to be safe by the caller.
1915            unsafe {
1916                intrinsics::unchecked_shl(self, rhs)
1917            }
1918        }
1919
1920        /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`.
1921        ///
1922        /// If `rhs` is larger or equal to the number of bits in `self`,
1923        /// the entire value is shifted out, and `0` is returned.
1924        ///
1925        /// # Examples
1926        ///
1927        /// ```
1928        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
1929        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(129), 0);")]
1930        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(0), 0b101);")]
1931        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(1), 0b1010);")]
1932        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(2), 0b10100);")]
1933        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(", stringify!($BITS), "), 0);")]
1934        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(1).unbounded_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
1935        ///
1936        #[doc = concat!("let start : ", stringify!($SelfT), " = 13;")]
1937        /// let mut running = start;
1938        /// for i in 0..160 {
1939        ///     // The unbounded shift left by i is the same as `<< 1` i times
1940        ///     assert_eq!(running, start.unbounded_shl(i));
1941        ///     // Which is not always the case for a wrapping shift
1942        #[doc = concat!("    assert_eq!(running == start.wrapping_shl(i), i < ", stringify!($BITS), ");")]
1943        ///
1944        ///     running <<= 1;
1945        /// }
1946        /// ```
1947        #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1948        #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1949        #[must_use = "this returns the result of the operation, \
1950                      without modifying the original"]
1951        #[inline]
1952        pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
1953            if rhs < Self::BITS {
1954                // SAFETY:
1955                // rhs is just checked to be in-range above
1956                unsafe { self.unchecked_shl(rhs) }
1957            } else {
1958                0
1959            }
1960        }
1961
1962        /// Exact shift left. Computes `self << rhs` as long as it can be reversed losslessly.
1963        ///
1964        /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
1965        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1966        /// Otherwise, returns `Some(self << rhs)`.
1967        ///
1968        /// # Examples
1969        ///
1970        /// ```
1971        /// #![feature(exact_bitshifts)]
1972        ///
1973        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(4), Some(0x10));")]
1974        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(129), None);")]
1975        /// ```
1976        #[unstable(feature = "exact_bitshifts", issue = "144336")]
1977        #[must_use = "this returns the result of the operation, \
1978                      without modifying the original"]
1979        #[inline]
1980        pub const fn shl_exact(self, rhs: u32) -> Option<$SelfT> {
1981            if rhs <= self.leading_zeros() && rhs < <$SelfT>::BITS {
1982                // SAFETY: rhs is checked above
1983                Some(unsafe { self.unchecked_shl(rhs) })
1984            } else {
1985                None
1986            }
1987        }
1988
1989        /// Unchecked exact shift left. Computes `self << rhs`, assuming the operation can be
1990        /// losslessly reversed `rhs` cannot be larger than
1991        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1992        ///
1993        /// # Safety
1994        ///
1995        /// This results in undefined behavior when `rhs > self.leading_zeros() || rhs >=
1996        #[doc = concat!(stringify!($SelfT), "::BITS`")]
1997        /// i.e. when
1998        #[doc = concat!("[`", stringify!($SelfT), "::shl_exact`]")]
1999        /// would return `None`.
2000        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2001        #[must_use = "this returns the result of the operation, \
2002                      without modifying the original"]
2003        #[inline]
2004        pub const unsafe fn unchecked_shl_exact(self, rhs: u32) -> $SelfT {
2005            assert_unsafe_precondition!(
2006                check_library_ub,
2007                concat!(stringify!($SelfT), "::unchecked_shl_exact cannot shift out non-zero bits"),
2008                (
2009                    zeros: u32 = self.leading_zeros(),
2010                    bits: u32 =  <$SelfT>::BITS,
2011                    rhs: u32 = rhs,
2012                ) => rhs <= zeros && rhs < bits,
2013            );
2014
2015            // SAFETY: this is guaranteed to be safe by the caller
2016            unsafe { self.unchecked_shl(rhs) }
2017        }
2018
2019        /// Checked shift right. Computes `self >> rhs`, returning `None`
2020        /// if `rhs` is larger than or equal to the number of bits in `self`.
2021        ///
2022        /// # Examples
2023        ///
2024        /// ```
2025        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
2026        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);")]
2027        /// ```
2028        #[stable(feature = "wrapping", since = "1.7.0")]
2029        #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
2030        #[must_use = "this returns the result of the operation, \
2031                      without modifying the original"]
2032        #[inline]
2033        pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
2034            // Not using overflowing_shr as that's a wrapping shift
2035            if rhs < Self::BITS {
2036                // SAFETY: just checked the RHS is in-range
2037                Some(unsafe { self.unchecked_shr(rhs) })
2038            } else {
2039                None
2040            }
2041        }
2042
2043        /// Strict shift right. Computes `self >> rhs`, panicking if `rhs` is
2044        /// larger than or equal to the number of bits in `self`.
2045        ///
2046        /// # Panics
2047        ///
2048        /// ## Overflow behavior
2049        ///
2050        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
2051        ///
2052        /// # Examples
2053        ///
2054        /// ```
2055        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
2056        /// ```
2057        ///
2058        /// The following panics because of overflow:
2059        ///
2060        /// ```should_panic
2061        #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(129);")]
2062        /// ```
2063        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
2064        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
2065        #[must_use = "this returns the result of the operation, \
2066                      without modifying the original"]
2067        #[inline]
2068        #[track_caller]
2069        pub const fn strict_shr(self, rhs: u32) -> Self {
2070            let (a, b) = self.overflowing_shr(rhs);
2071            if b { overflow_panic::shr() } else { a }
2072        }
2073
2074        /// Unchecked shift right. Computes `self >> rhs`, assuming that
2075        /// `rhs` is less than the number of bits in `self`.
2076        ///
2077        /// # Safety
2078        ///
2079        /// This results in undefined behavior if `rhs` is larger than
2080        /// or equal to the number of bits in `self`,
2081        /// i.e. when [`checked_shr`] would return `None`.
2082        ///
2083        #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
2084        #[stable(feature = "unchecked_shifts", since = "1.93.0")]
2085        #[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
2086        #[must_use = "this returns the result of the operation, \
2087                      without modifying the original"]
2088        #[inline(always)]
2089        #[track_caller]
2090        pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
2091            assert_unsafe_precondition!(
2092                check_language_ub,
2093                concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
2094                (
2095                    rhs: u32 = rhs,
2096                ) => rhs < <$ActualT>::BITS,
2097            );
2098
2099            // SAFETY: this is guaranteed to be safe by the caller.
2100            unsafe {
2101                intrinsics::unchecked_shr(self, rhs)
2102            }
2103        }
2104
2105        /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`.
2106        ///
2107        /// If `rhs` is larger or equal to the number of bits in `self`,
2108        /// the entire value is shifted out, and `0` is returned.
2109        ///
2110        /// # Examples
2111        ///
2112        /// ```
2113        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
2114        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(129), 0);")]
2115        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(0), 0b1010);")]
2116        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(1), 0b101);")]
2117        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(2), 0b10);")]
2118        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(", stringify!($BITS), "), 0);")]
2119        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(1).unbounded_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
2120        ///
2121        #[doc = concat!("let start = ", stringify!($SelfT), "::rotate_right(13, 4);")]
2122        /// let mut running = start;
2123        /// for i in 0..160 {
2124        ///     // The unbounded shift right by i is the same as `>> 1` i times
2125        ///     assert_eq!(running, start.unbounded_shr(i));
2126        ///     // Which is not always the case for a wrapping shift
2127        #[doc = concat!("    assert_eq!(running == start.wrapping_shr(i), i < ", stringify!($BITS), ");")]
2128        ///
2129        ///     running >>= 1;
2130        /// }
2131        /// ```
2132        #[stable(feature = "unbounded_shifts", since = "1.87.0")]
2133        #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
2134        #[must_use = "this returns the result of the operation, \
2135                      without modifying the original"]
2136        #[inline]
2137        pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
2138            if rhs < Self::BITS {
2139                // SAFETY:
2140                // rhs is just checked to be in-range above
2141                unsafe { self.unchecked_shr(rhs) }
2142            } else {
2143                0
2144            }
2145        }
2146
2147        /// Exact shift right. Computes `self >> rhs` as long as it can be reversed losslessly.
2148        ///
2149        /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
2150        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
2151        /// Otherwise, returns `Some(self >> rhs)`.
2152        ///
2153        /// # Examples
2154        ///
2155        /// ```
2156        /// #![feature(exact_bitshifts)]
2157        ///
2158        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(4), Some(0x1));")]
2159        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(5), None);")]
2160        /// ```
2161        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2162        #[must_use = "this returns the result of the operation, \
2163                      without modifying the original"]
2164        #[inline]
2165        pub const fn shr_exact(self, rhs: u32) -> Option<$SelfT> {
2166            if rhs <= self.trailing_zeros() && rhs < <$SelfT>::BITS {
2167                // SAFETY: rhs is checked above
2168                Some(unsafe { self.unchecked_shr(rhs) })
2169            } else {
2170                None
2171            }
2172        }
2173
2174        /// Unchecked exact shift right. Computes `self >> rhs`, assuming the operation can be
2175        /// losslessly reversed and `rhs` cannot be larger than
2176        #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
2177        ///
2178        /// # Safety
2179        ///
2180        /// This results in undefined behavior when `rhs > self.trailing_zeros() || rhs >=
2181        #[doc = concat!(stringify!($SelfT), "::BITS`")]
2182        /// i.e. when
2183        #[doc = concat!("[`", stringify!($SelfT), "::shr_exact`]")]
2184        /// would return `None`.
2185        #[unstable(feature = "exact_bitshifts", issue = "144336")]
2186        #[must_use = "this returns the result of the operation, \
2187                      without modifying the original"]
2188        #[inline]
2189        pub const unsafe fn unchecked_shr_exact(self, rhs: u32) -> $SelfT {
2190            assert_unsafe_precondition!(
2191                check_library_ub,
2192                concat!(stringify!($SelfT), "::unchecked_shr_exact cannot shift out non-zero bits"),
2193                (
2194                    zeros: u32 = self.trailing_zeros(),
2195                    bits: u32 =  <$SelfT>::BITS,
2196                    rhs: u32 = rhs,
2197                ) => rhs <= zeros && rhs < bits,
2198            );
2199
2200            // SAFETY: this is guaranteed to be safe by the caller
2201            unsafe { self.unchecked_shr(rhs) }
2202        }
2203
2204        /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
2205        /// overflow occurred.
2206        ///
2207        /// # Examples
2208        ///
2209        /// ```
2210        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")]
2211        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".checked_pow(0), Some(1));")]
2212        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
2213        /// ```
2214        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2215        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2216        #[must_use = "this returns the result of the operation, \
2217                      without modifying the original"]
2218        #[inline]
2219        pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
2220            if exp == 0 {
2221                return Some(1);
2222            }
2223            let mut base = self;
2224            let mut acc: Self = 1;
2225
2226            loop {
2227                if (exp & 1) == 1 {
2228                    acc = try_opt!(acc.checked_mul(base));
2229                    // since exp!=0, finally the exp must be 1.
2230                    if exp == 1 {
2231                        return Some(acc);
2232                    }
2233                }
2234                exp /= 2;
2235                base = try_opt!(base.checked_mul(base));
2236            }
2237        }
2238
2239        /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
2240        /// overflow occurred.
2241        ///
2242        /// # Panics
2243        ///
2244        /// ## Overflow behavior
2245        ///
2246        /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
2247        ///
2248        /// # Examples
2249        ///
2250        /// ```
2251        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".strict_pow(5), 32);")]
2252        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".strict_pow(0), 1);")]
2253        /// ```
2254        ///
2255        /// The following panics because of overflow:
2256        ///
2257        /// ```should_panic
2258        #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
2259        /// ```
2260        #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
2261        #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
2262        #[must_use = "this returns the result of the operation, \
2263                      without modifying the original"]
2264        #[inline]
2265        #[track_caller]
2266        pub const fn strict_pow(self, mut exp: u32) -> Self {
2267            if exp == 0 {
2268                return 1;
2269            }
2270            let mut base = self;
2271            let mut acc: Self = 1;
2272
2273            loop {
2274                if (exp & 1) == 1 {
2275                    acc = acc.strict_mul(base);
2276                    // since exp!=0, finally the exp must be 1.
2277                    if exp == 1 {
2278                        return acc;
2279                    }
2280                }
2281                exp /= 2;
2282                base = base.strict_mul(base);
2283            }
2284        }
2285
2286        /// Saturating integer addition. Computes `self + rhs`, saturating at
2287        /// the numeric bounds instead of overflowing.
2288        ///
2289        /// # Examples
2290        ///
2291        /// ```
2292        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
2293        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);")]
2294        /// ```
2295        #[stable(feature = "rust1", since = "1.0.0")]
2296        #[must_use = "this returns the result of the operation, \
2297                      without modifying the original"]
2298        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2299        #[inline(always)]
2300        pub const fn saturating_add(self, rhs: Self) -> Self {
2301            intrinsics::saturating_add(self, rhs)
2302        }
2303
2304        /// Saturating addition with a signed integer. Computes `self + rhs`,
2305        /// saturating at the numeric bounds instead of overflowing.
2306        ///
2307        /// # Examples
2308        ///
2309        /// ```
2310        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")]
2311        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")]
2312        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")]
2313        /// ```
2314        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2315        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2316        #[must_use = "this returns the result of the operation, \
2317                      without modifying the original"]
2318        #[inline]
2319        pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
2320            let (res, overflow) = self.overflowing_add(rhs as Self);
2321            if overflow == (rhs < 0) {
2322                res
2323            } else if overflow {
2324                Self::MAX
2325            } else {
2326                0
2327            }
2328        }
2329
2330        /// Saturating integer subtraction. Computes `self - rhs`, saturating
2331        /// at the numeric bounds instead of overflowing.
2332        ///
2333        /// # Examples
2334        ///
2335        /// ```
2336        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")]
2337        #[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")]
2338        /// ```
2339        #[stable(feature = "rust1", since = "1.0.0")]
2340        #[must_use = "this returns the result of the operation, \
2341                      without modifying the original"]
2342        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2343        #[inline(always)]
2344        pub const fn saturating_sub(self, rhs: Self) -> Self {
2345            intrinsics::saturating_sub(self, rhs)
2346        }
2347
2348        /// Saturating integer subtraction. Computes `self` - `rhs`, saturating at
2349        /// the numeric bounds instead of overflowing.
2350        ///
2351        /// # Examples
2352        ///
2353        /// ```
2354        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(2), 0);")]
2355        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(-2), 3);")]
2356        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_sub_signed(-4), ", stringify!($SelfT), "::MAX);")]
2357        /// ```
2358        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2359        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2360        #[must_use = "this returns the result of the operation, \
2361                      without modifying the original"]
2362        #[inline]
2363        pub const fn saturating_sub_signed(self, rhs: $SignedT) -> Self {
2364            let (res, overflow) = self.overflowing_sub_signed(rhs);
2365
2366            if !overflow {
2367                res
2368            } else if rhs < 0 {
2369                Self::MAX
2370            } else {
2371                0
2372            }
2373        }
2374
2375        /// Saturating integer multiplication. Computes `self * rhs`,
2376        /// saturating at the numeric bounds instead of overflowing.
2377        ///
2378        /// # Examples
2379        ///
2380        /// ```
2381        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20);")]
2382        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT),"::MAX);")]
2383        /// ```
2384        #[stable(feature = "wrapping", since = "1.7.0")]
2385        #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2386        #[must_use = "this returns the result of the operation, \
2387                      without modifying the original"]
2388        #[inline]
2389        pub const fn saturating_mul(self, rhs: Self) -> Self {
2390            match self.checked_mul(rhs) {
2391                Some(x) => x,
2392                None => Self::MAX,
2393            }
2394        }
2395
2396        /// Saturating integer division. Computes `self / rhs`, saturating at the
2397        /// numeric bounds instead of overflowing.
2398        ///
2399        /// # Panics
2400        ///
2401        /// This function will panic if `rhs` is zero.
2402        ///
2403        /// # Examples
2404        ///
2405        /// ```
2406        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
2407        ///
2408        /// ```
2409        #[stable(feature = "saturating_div", since = "1.58.0")]
2410        #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
2411        #[must_use = "this returns the result of the operation, \
2412                      without modifying the original"]
2413        #[inline]
2414        #[track_caller]
2415        pub const fn saturating_div(self, rhs: Self) -> Self {
2416            // on unsigned types, there is no overflow in integer division
2417            self.wrapping_div(rhs)
2418        }
2419
2420        /// Saturating integer exponentiation. Computes `self.pow(exp)`,
2421        /// saturating at the numeric bounds instead of overflowing.
2422        ///
2423        /// # Examples
2424        ///
2425        /// ```
2426        #[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")]
2427        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".saturating_pow(0), 1);")]
2428        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
2429        /// ```
2430        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2431        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2432        #[must_use = "this returns the result of the operation, \
2433                      without modifying the original"]
2434        #[inline]
2435        pub const fn saturating_pow(self, exp: u32) -> Self {
2436            match self.checked_pow(exp) {
2437                Some(x) => x,
2438                None => Self::MAX,
2439            }
2440        }
2441
2442        /// Wrapping (modular) addition. Computes `self + rhs`,
2443        /// wrapping around at the boundary of the type.
2444        ///
2445        /// # Examples
2446        ///
2447        /// ```
2448        #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255);")]
2449        #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);")]
2450        /// ```
2451        #[stable(feature = "rust1", since = "1.0.0")]
2452        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2453        #[must_use = "this returns the result of the operation, \
2454                      without modifying the original"]
2455        #[inline(always)]
2456        pub const fn wrapping_add(self, rhs: Self) -> Self {
2457            intrinsics::wrapping_add(self, rhs)
2458        }
2459
2460        /// Wrapping (modular) addition with a signed integer. Computes
2461        /// `self + rhs`, wrapping around at the boundary of the type.
2462        ///
2463        /// # Examples
2464        ///
2465        /// ```
2466        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")]
2467        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")]
2468        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")]
2469        /// ```
2470        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2471        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2472        #[must_use = "this returns the result of the operation, \
2473                      without modifying the original"]
2474        #[inline]
2475        pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self {
2476            self.wrapping_add(rhs as Self)
2477        }
2478
2479        /// Wrapping (modular) subtraction. Computes `self - rhs`,
2480        /// wrapping around at the boundary of the type.
2481        ///
2482        /// # Examples
2483        ///
2484        /// ```
2485        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0);")]
2486        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);")]
2487        /// ```
2488        #[stable(feature = "rust1", since = "1.0.0")]
2489        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2490        #[must_use = "this returns the result of the operation, \
2491                      without modifying the original"]
2492        #[inline(always)]
2493        pub const fn wrapping_sub(self, rhs: Self) -> Self {
2494            intrinsics::wrapping_sub(self, rhs)
2495        }
2496
2497        /// Wrapping (modular) subtraction with a signed integer. Computes
2498        /// `self - rhs`, wrapping around at the boundary of the type.
2499        ///
2500        /// # Examples
2501        ///
2502        /// ```
2503        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(2), ", stringify!($SelfT), "::MAX);")]
2504        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(-2), 3);")]
2505        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_sub_signed(-4), 1);")]
2506        /// ```
2507        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2508        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2509        #[must_use = "this returns the result of the operation, \
2510                      without modifying the original"]
2511        #[inline]
2512        pub const fn wrapping_sub_signed(self, rhs: $SignedT) -> Self {
2513            self.wrapping_sub(rhs as Self)
2514        }
2515
2516        /// Wrapping (modular) multiplication. Computes `self *
2517        /// rhs`, wrapping around at the boundary of the type.
2518        ///
2519        /// # Examples
2520        ///
2521        /// Please note that this example is shared among integer types, which is why `u8` is used.
2522        ///
2523        /// ```
2524        /// assert_eq!(10u8.wrapping_mul(12), 120);
2525        /// assert_eq!(25u8.wrapping_mul(12), 44);
2526        /// ```
2527        #[stable(feature = "rust1", since = "1.0.0")]
2528        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2529        #[must_use = "this returns the result of the operation, \
2530                      without modifying the original"]
2531        #[inline(always)]
2532        pub const fn wrapping_mul(self, rhs: Self) -> Self {
2533            intrinsics::wrapping_mul(self, rhs)
2534        }
2535
2536        /// Wrapping (modular) division. Computes `self / rhs`.
2537        ///
2538        /// Wrapped division on unsigned types is just normal division. There's
2539        /// no way wrapping could ever happen. This function exists so that all
2540        /// operations are accounted for in the wrapping operations.
2541        ///
2542        /// # Panics
2543        ///
2544        /// This function will panic if `rhs` is zero.
2545        ///
2546        /// # Examples
2547        ///
2548        /// ```
2549        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
2550        /// ```
2551        #[stable(feature = "num_wrapping", since = "1.2.0")]
2552        #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2553        #[must_use = "this returns the result of the operation, \
2554                      without modifying the original"]
2555        #[inline(always)]
2556        #[track_caller]
2557        pub const fn wrapping_div(self, rhs: Self) -> Self {
2558            self / rhs
2559        }
2560
2561        /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`.
2562        ///
2563        /// Wrapped division on unsigned types is just normal division. There's
2564        /// no way wrapping could ever happen. This function exists so that all
2565        /// operations are accounted for in the wrapping operations. Since, for
2566        /// the positive integers, all common definitions of division are equal,
2567        /// this is exactly equal to `self.wrapping_div(rhs)`.
2568        ///
2569        /// # Panics
2570        ///
2571        /// This function will panic if `rhs` is zero.
2572        ///
2573        /// # Examples
2574        ///
2575        /// ```
2576        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
2577        /// ```
2578        #[stable(feature = "euclidean_division", since = "1.38.0")]
2579        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2580        #[must_use = "this returns the result of the operation, \
2581                      without modifying the original"]
2582        #[inline(always)]
2583        #[track_caller]
2584        pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
2585            self / rhs
2586        }
2587
2588        /// Wrapping (modular) remainder. Computes `self % rhs`.
2589        ///
2590        /// Wrapped remainder calculation on unsigned types is just the regular
2591        /// remainder calculation. There's no way wrapping could ever happen.
2592        /// This function exists so that all operations are accounted for in the
2593        /// wrapping operations.
2594        ///
2595        /// # Panics
2596        ///
2597        /// This function will panic if `rhs` is zero.
2598        ///
2599        /// # Examples
2600        ///
2601        /// ```
2602        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
2603        /// ```
2604        #[stable(feature = "num_wrapping", since = "1.2.0")]
2605        #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2606        #[must_use = "this returns the result of the operation, \
2607                      without modifying the original"]
2608        #[inline(always)]
2609        #[track_caller]
2610        pub const fn wrapping_rem(self, rhs: Self) -> Self {
2611            self % rhs
2612        }
2613
2614        /// Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`.
2615        ///
2616        /// Wrapped modulo calculation on unsigned types is just the regular
2617        /// remainder calculation. There's no way wrapping could ever happen.
2618        /// This function exists so that all operations are accounted for in the
2619        /// wrapping operations. Since, for the positive integers, all common
2620        /// definitions of division are equal, this is exactly equal to
2621        /// `self.wrapping_rem(rhs)`.
2622        ///
2623        /// # Panics
2624        ///
2625        /// This function will panic if `rhs` is zero.
2626        ///
2627        /// # Examples
2628        ///
2629        /// ```
2630        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
2631        /// ```
2632        #[stable(feature = "euclidean_division", since = "1.38.0")]
2633        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2634        #[must_use = "this returns the result of the operation, \
2635                      without modifying the original"]
2636        #[inline(always)]
2637        #[track_caller]
2638        pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
2639            self % rhs
2640        }
2641
2642        /// Wrapping (modular) negation. Computes `-self`,
2643        /// wrapping around at the boundary of the type.
2644        ///
2645        /// Since unsigned types do not have negative equivalents
2646        /// all applications of this function will wrap (except for `-0`).
2647        /// For values smaller than the corresponding signed type's maximum
2648        /// the result is the same as casting the corresponding signed value.
2649        /// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where
2650        /// `MAX` is the corresponding signed type's maximum.
2651        ///
2652        /// # Examples
2653        ///
2654        /// ```
2655        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_neg(), 0);")]
2656        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_neg(), 1);")]
2657        #[doc = concat!("assert_eq!(13_", stringify!($SelfT), ".wrapping_neg(), (!13) + 1);")]
2658        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_neg(), !(42 - 1));")]
2659        /// ```
2660        #[stable(feature = "num_wrapping", since = "1.2.0")]
2661        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2662        #[must_use = "this returns the result of the operation, \
2663                      without modifying the original"]
2664        #[inline(always)]
2665        pub const fn wrapping_neg(self) -> Self {
2666            (0 as $SelfT).wrapping_sub(self)
2667        }
2668
2669        /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
2670        /// where `mask` removes any high-order bits of `rhs` that
2671        /// would cause the shift to exceed the bitwidth of the type.
2672        ///
2673        /// Beware that, unlike most other `wrapping_*` methods on integers, this
2674        /// does *not* give the same result as doing the shift in infinite precision
2675        /// then truncating as needed.  The behaviour matches what shift instructions
2676        /// do on many processors, and is what the `<<` operator does when overflow
2677        /// checks are disabled, but numerically it's weird.  Consider, instead,
2678        /// using [`Self::unbounded_shl`] which has nicer behaviour.
2679        ///
2680        /// Note that this is *not* the same as a rotate-left; the
2681        /// RHS of a wrapping shift-left is restricted to the range
2682        /// of the type, rather than the bits shifted out of the LHS
2683        /// being returned to the other end. The primitive integer
2684        /// types all implement a [`rotate_left`](Self::rotate_left) function,
2685        /// which may be what you want instead.
2686        ///
2687        /// # Examples
2688        ///
2689        /// ```
2690        #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".wrapping_shl(7), 128);")]
2691        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(0), 0b101);")]
2692        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(1), 0b1010);")]
2693        #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".wrapping_shl(2), 0b10100);")]
2694        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_shl(2), ", stringify!($SelfT), "::MAX - 3);")]
2695        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(", stringify!($BITS), "), 42);")]
2696        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(1).wrapping_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
2697        #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".wrapping_shl(128), 1);")]
2698        #[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".wrapping_shl(1025), 10);")]
2699        /// ```
2700        #[stable(feature = "num_wrapping", since = "1.2.0")]
2701        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2702        #[must_use = "this returns the result of the operation, \
2703                      without modifying the original"]
2704        #[inline(always)]
2705        pub const fn wrapping_shl(self, rhs: u32) -> Self {
2706            // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2707            // out of bounds
2708            unsafe {
2709                self.unchecked_shl(rhs & (Self::BITS - 1))
2710            }
2711        }
2712
2713        /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
2714        /// where `mask` removes any high-order bits of `rhs` that
2715        /// would cause the shift to exceed the bitwidth of the type.
2716        ///
2717        /// Beware that, unlike most other `wrapping_*` methods on integers, this
2718        /// does *not* give the same result as doing the shift in infinite precision
2719        /// then truncating as needed.  The behaviour matches what shift instructions
2720        /// do on many processors, and is what the `>>` operator does when overflow
2721        /// checks are disabled, but numerically it's weird.  Consider, instead,
2722        /// using [`Self::unbounded_shr`] which has nicer behaviour.
2723        ///
2724        /// Note that this is *not* the same as a rotate-right; the
2725        /// RHS of a wrapping shift-right is restricted to the range
2726        /// of the type, rather than the bits shifted out of the LHS
2727        /// being returned to the other end. The primitive integer
2728        /// types all implement a [`rotate_right`](Self::rotate_right) function,
2729        /// which may be what you want instead.
2730        ///
2731        /// # Examples
2732        ///
2733        /// ```
2734        #[doc = concat!("assert_eq!(128_", stringify!($SelfT), ".wrapping_shr(7), 1);")]
2735        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(0), 0b1010);")]
2736        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(1), 0b101);")]
2737        #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".wrapping_shr(2), 0b10);")]
2738        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_shr(1), ", stringify!($SignedT), "::MAX.cast_unsigned());")]
2739        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(", stringify!($BITS), "), 42);")]
2740        #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(1).wrapping_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
2741        #[doc = concat!("assert_eq!(128_", stringify!($SelfT), ".wrapping_shr(128), 128);")]
2742        #[doc = concat!("assert_eq!(10_", stringify!($SelfT), ".wrapping_shr(1025), 5);")]
2743        /// ```
2744        #[stable(feature = "num_wrapping", since = "1.2.0")]
2745        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2746        #[must_use = "this returns the result of the operation, \
2747                      without modifying the original"]
2748        #[inline(always)]
2749        pub const fn wrapping_shr(self, rhs: u32) -> Self {
2750            // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2751            // out of bounds
2752            unsafe {
2753                self.unchecked_shr(rhs & (Self::BITS - 1))
2754            }
2755        }
2756
2757        /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
2758        /// wrapping around at the boundary of the type.
2759        ///
2760        /// # Examples
2761        ///
2762        /// ```
2763        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")]
2764        /// assert_eq!(3u8.wrapping_pow(6), 217);
2765        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_pow(0), 1);")]
2766        /// ```
2767        #[stable(feature = "no_panic_pow", since = "1.34.0")]
2768        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2769        #[must_use = "this returns the result of the operation, \
2770                      without modifying the original"]
2771        #[inline]
2772        pub const fn wrapping_pow(self, mut exp: u32) -> Self {
2773            if exp == 0 {
2774                return 1;
2775            }
2776            let mut base = self;
2777            let mut acc: Self = 1;
2778
2779            if intrinsics::is_val_statically_known(exp) {
2780                while exp > 1 {
2781                    if (exp & 1) == 1 {
2782                        acc = acc.wrapping_mul(base);
2783                    }
2784                    exp /= 2;
2785                    base = base.wrapping_mul(base);
2786                }
2787
2788                // since exp!=0, finally the exp must be 1.
2789                // Deal with the final bit of the exponent separately, since
2790                // squaring the base afterwards is not necessary.
2791                acc.wrapping_mul(base)
2792            } else {
2793                // This is faster than the above when the exponent is not known
2794                // at compile time. We can't use the same code for the constant
2795                // exponent case because LLVM is currently unable to unroll
2796                // this loop.
2797                loop {
2798                    if (exp & 1) == 1 {
2799                        acc = acc.wrapping_mul(base);
2800                        // since exp!=0, finally the exp must be 1.
2801                        if exp == 1 {
2802                            return acc;
2803                        }
2804                    }
2805                    exp /= 2;
2806                    base = base.wrapping_mul(base);
2807                }
2808            }
2809        }
2810
2811        /// Calculates `self` + `rhs`.
2812        ///
2813        /// Returns a tuple of the addition along with a boolean indicating
2814        /// whether an arithmetic overflow would occur. If an overflow would
2815        /// have occurred then the wrapped value is returned.
2816        ///
2817        /// # Examples
2818        ///
2819        /// ```
2820        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
2821        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));")]
2822        /// ```
2823        #[stable(feature = "wrapping", since = "1.7.0")]
2824        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2825        #[must_use = "this returns the result of the operation, \
2826                      without modifying the original"]
2827        #[inline(always)]
2828        pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
2829            let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
2830            (a as Self, b)
2831        }
2832
2833        /// Calculates `self` + `rhs` + `carry` and returns a tuple containing
2834        /// the sum and the output carry (in that order).
2835        ///
2836        /// Performs "ternary addition" of two integer operands and a carry-in
2837        /// bit, and returns an output integer and a carry-out bit. This allows
2838        /// chaining together multiple additions to create a wider addition, and
2839        /// can be useful for bignum addition.
2840        ///
2841        #[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit \"full adder\", in the electronics sense.")]
2842        ///
2843        /// If the input carry is false, this method is equivalent to
2844        /// [`overflowing_add`](Self::overflowing_add), and the output carry is
2845        /// equal to the overflow flag. Note that although carry and overflow
2846        /// flags are similar for unsigned integers, they are different for
2847        /// signed integers.
2848        ///
2849        /// # Examples
2850        ///
2851        /// ```
2852        #[doc = concat!("//    3  MAX    (a = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2853        #[doc = concat!("// +  5    7    (b = 5 × 2^", stringify!($BITS), " + 7)")]
2854        /// // ---------
2855        #[doc = concat!("//    9    6    (sum = 9 × 2^", stringify!($BITS), " + 6)")]
2856        ///
2857        #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (3, ", stringify!($SelfT), "::MAX);")]
2858        #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
2859        /// let carry0 = false;
2860        ///
2861        /// let (sum0, carry1) = a0.carrying_add(b0, carry0);
2862        /// assert_eq!(carry1, true);
2863        /// let (sum1, carry2) = a1.carrying_add(b1, carry1);
2864        /// assert_eq!(carry2, false);
2865        ///
2866        /// assert_eq!((sum1, sum0), (9, 6));
2867        /// ```
2868        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
2869        #[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
2870        #[must_use = "this returns the result of the operation, \
2871                      without modifying the original"]
2872        #[inline]
2873        pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
2874            // note: longer-term this should be done via an intrinsic, but this has been shown
2875            //   to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
2876            let (a, c1) = self.overflowing_add(rhs);
2877            let (b, c2) = a.overflowing_add(carry as $SelfT);
2878            // Ideally LLVM would know this is disjoint without us telling them,
2879            // but it doesn't <https://github.com/llvm/llvm-project/issues/118162>
2880            // SAFETY: Only one of `c1` and `c2` can be set.
2881            // For c1 to be set we need to have overflowed, but if we did then
2882            // `a` is at most `MAX-1`, which means that `c2` cannot possibly
2883            // overflow because it's adding at most `1` (since it came from `bool`)
2884            (b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
2885        }
2886
2887        /// Calculates `self` + `rhs` with a signed `rhs`.
2888        ///
2889        /// Returns a tuple of the addition along with a boolean indicating
2890        /// whether an arithmetic overflow would occur. If an overflow would
2891        /// have occurred then the wrapped value is returned.
2892        ///
2893        /// # Examples
2894        ///
2895        /// ```
2896        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")]
2897        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")]
2898        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")]
2899        /// ```
2900        #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2901        #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2902        #[must_use = "this returns the result of the operation, \
2903                      without modifying the original"]
2904        #[inline]
2905        pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
2906            let (res, overflowed) = self.overflowing_add(rhs as Self);
2907            (res, overflowed ^ (rhs < 0))
2908        }
2909
2910        /// Calculates `self` - `rhs`.
2911        ///
2912        /// Returns a tuple of the subtraction along with a boolean indicating
2913        /// whether an arithmetic overflow would occur. If an overflow would
2914        /// have occurred then the wrapped value is returned.
2915        ///
2916        /// # Examples
2917        ///
2918        /// ```
2919        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
2920        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
2921        /// ```
2922        #[stable(feature = "wrapping", since = "1.7.0")]
2923        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2924        #[must_use = "this returns the result of the operation, \
2925                      without modifying the original"]
2926        #[inline(always)]
2927        pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
2928            let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
2929            (a as Self, b)
2930        }
2931
2932        /// Calculates `self` &minus; `rhs` &minus; `borrow` and returns a tuple
2933        /// containing the difference and the output borrow.
2934        ///
2935        /// Performs "ternary subtraction" by subtracting both an integer
2936        /// operand and a borrow-in bit from `self`, and returns an output
2937        /// integer and a borrow-out bit. This allows chaining together multiple
2938        /// subtractions to create a wider subtraction, and can be useful for
2939        /// bignum subtraction.
2940        ///
2941        /// # Examples
2942        ///
2943        /// ```
2944        #[doc = concat!("//    9    6    (a = 9 × 2^", stringify!($BITS), " + 6)")]
2945        #[doc = concat!("// -  5    7    (b = 5 × 2^", stringify!($BITS), " + 7)")]
2946        /// // ---------
2947        #[doc = concat!("//    3  MAX    (diff = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2948        ///
2949        #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (9, 6);")]
2950        #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
2951        /// let borrow0 = false;
2952        ///
2953        /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
2954        /// assert_eq!(borrow1, true);
2955        /// let (diff1, borrow2) = a1.borrowing_sub(b1, borrow1);
2956        /// assert_eq!(borrow2, false);
2957        ///
2958        #[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")]
2959        /// ```
2960        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
2961        #[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
2962        #[must_use = "this returns the result of the operation, \
2963                      without modifying the original"]
2964        #[inline]
2965        pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
2966            // note: longer-term this should be done via an intrinsic, but this has been shown
2967            //   to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
2968            let (a, c1) = self.overflowing_sub(rhs);
2969            let (b, c2) = a.overflowing_sub(borrow as $SelfT);
2970            // SAFETY: Only one of `c1` and `c2` can be set.
2971            // For c1 to be set we need to have underflowed, but if we did then
2972            // `a` is nonzero, which means that `c2` cannot possibly
2973            // underflow because it's subtracting at most `1` (since it came from `bool`)
2974            (b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
2975        }
2976
2977        /// Calculates `self` - `rhs` with a signed `rhs`
2978        ///
2979        /// Returns a tuple of the subtraction along with a boolean indicating
2980        /// whether an arithmetic overflow would occur. If an overflow would
2981        /// have occurred then the wrapped value is returned.
2982        ///
2983        /// # Examples
2984        ///
2985        /// ```
2986        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(2), (", stringify!($SelfT), "::MAX, true));")]
2987        #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(-2), (3, false));")]
2988        #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_sub_signed(-4), (1, true));")]
2989        /// ```
2990        #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2991        #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2992        #[must_use = "this returns the result of the operation, \
2993                      without modifying the original"]
2994        #[inline]
2995        pub const fn overflowing_sub_signed(self, rhs: $SignedT) -> (Self, bool) {
2996            let (res, overflow) = self.overflowing_sub(rhs as Self);
2997
2998            (res, overflow ^ (rhs < 0))
2999        }
3000
3001        /// Computes the absolute difference between `self` and `other`.
3002        ///
3003        /// # Examples
3004        ///
3005        /// ```
3006        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($SelfT), ");")]
3007        #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($SelfT), ");")]
3008        /// ```
3009        #[stable(feature = "int_abs_diff", since = "1.60.0")]
3010        #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
3011        #[must_use = "this returns the result of the operation, \
3012                      without modifying the original"]
3013        #[inline]
3014        pub const fn abs_diff(self, other: Self) -> Self {
3015            if size_of::<Self>() == 1 {
3016                // Trick LLVM into generating the psadbw instruction when SSE2
3017                // is available and this function is autovectorized for u8's.
3018                (self as i32).wrapping_sub(other as i32).unsigned_abs() as Self
3019            } else {
3020                if self < other {
3021                    other - self
3022                } else {
3023                    self - other
3024                }
3025            }
3026        }
3027
3028        /// Calculates the multiplication of `self` and `rhs`.
3029        ///
3030        /// Returns a tuple of the multiplication along with a boolean
3031        /// indicating whether an arithmetic overflow would occur. If an
3032        /// overflow would have occurred then the wrapped value is returned.
3033        ///
3034        /// If you want the *value* of the overflow, rather than just *whether*
3035        /// an overflow occurred, see [`Self::carrying_mul`].
3036        ///
3037        /// # Examples
3038        ///
3039        /// Please note that this example is shared among integer types, which is why `u32` is used.
3040        ///
3041        /// ```
3042        /// assert_eq!(5u32.overflowing_mul(2), (10, false));
3043        /// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
3044        /// ```
3045        #[stable(feature = "wrapping", since = "1.7.0")]
3046        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3047        #[must_use = "this returns the result of the operation, \
3048                          without modifying the original"]
3049        #[inline(always)]
3050        pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
3051            let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
3052            (a as Self, b)
3053        }
3054
3055        /// Calculates the complete double-width product `self * rhs`.
3056        ///
3057        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
3058        /// of the result as two separate values, in that order. As such,
3059        /// `a.widening_mul(b).0` produces the same result as `a.wrapping_mul(b)`.
3060        ///
3061        /// If you also need to add a value and carry to the wide result, then you want
3062        /// [`Self::carrying_mul_add`] instead.
3063        ///
3064        /// If you also need to add a carry to the wide result, then you want
3065        /// [`Self::carrying_mul`] instead.
3066        ///
3067        /// If you just want to know *whether* the multiplication overflowed, then you
3068        /// want [`Self::overflowing_mul`] instead.
3069        ///
3070        /// # Examples
3071        ///
3072        /// ```
3073        /// #![feature(widening_mul)]
3074        #[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".widening_mul(7), (35, 0));")]
3075        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.widening_mul(", stringify!($SelfT), "::MAX), (1, ", stringify!($SelfT), "::MAX - 1));")]
3076        /// ```
3077        ///
3078        /// Compared to other `*_mul` methods:
3079        /// ```
3080        /// #![feature(widening_mul)]
3081        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::widening_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), (0, 3));")]
3082        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::overflowing_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), (0, true));")]
3083        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::wrapping_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), 0);")]
3084        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::checked_mul(1 << ", stringify!($BITS_MINUS_ONE), ", 6), None);")]
3085        /// ```
3086        ///
3087        /// Please note that this example is shared among integer types, which is why `u32` is used.
3088        ///
3089        /// ```
3090        /// #![feature(widening_mul)]
3091        /// assert_eq!(5u32.widening_mul(2), (10, 0));
3092        /// assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2));
3093        /// ```
3094        #[unstable(feature = "widening_mul", issue = "152016")]
3095        #[rustc_const_unstable(feature = "widening_mul", issue = "152016")]
3096        #[must_use = "this returns the result of the operation, \
3097                      without modifying the original"]
3098        #[inline]
3099        pub const fn widening_mul(self, rhs: Self) -> (Self, Self) {
3100            Self::carrying_mul_add(self, rhs, 0, 0)
3101        }
3102
3103        /// Calculates the "full multiplication" `self * rhs + carry`
3104        /// without the possibility to overflow.
3105        ///
3106        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
3107        /// of the result as two separate values, in that order.
3108        ///
3109        /// Performs "long multiplication" which takes in an extra amount to add, and may return an
3110        /// additional amount of overflow. This allows for chaining together multiple
3111        /// multiplications to create "big integers" which represent larger values.
3112        ///
3113        /// If you also need to add a value, then use [`Self::carrying_mul_add`].
3114        ///
3115        /// # Examples
3116        ///
3117        /// Please note that this example is shared among integer types, which is why `u32` is used.
3118        ///
3119        /// ```
3120        /// assert_eq!(5u32.carrying_mul(2, 0), (10, 0));
3121        /// assert_eq!(5u32.carrying_mul(2, 10), (20, 0));
3122        /// assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2));
3123        /// assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2));
3124        #[doc = concat!("assert_eq!(",
3125            stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
3126            "(0, ", stringify!($SelfT), "::MAX));"
3127        )]
3128        /// ```
3129        ///
3130        /// This is the core operation needed for scalar multiplication when
3131        /// implementing it for wider-than-native types.
3132        ///
3133        /// ```
3134        /// fn scalar_mul_eq(little_endian_digits: &mut Vec<u16>, multiplicand: u16) {
3135        ///     let mut carry = 0;
3136        ///     for d in little_endian_digits.iter_mut() {
3137        ///         (*d, carry) = d.carrying_mul(multiplicand, carry);
3138        ///     }
3139        ///     if carry != 0 {
3140        ///         little_endian_digits.push(carry);
3141        ///     }
3142        /// }
3143        ///
3144        /// let mut v = vec![10, 20];
3145        /// scalar_mul_eq(&mut v, 3);
3146        /// assert_eq!(v, [30, 60]);
3147        ///
3148        /// assert_eq!(0x87654321_u64 * 0xFEED, 0x86D3D159E38D);
3149        /// let mut v = vec![0x4321, 0x8765];
3150        /// scalar_mul_eq(&mut v, 0xFEED);
3151        /// assert_eq!(v, [0xE38D, 0xD159, 0x86D3]);
3152        /// ```
3153        ///
3154        /// If `carry` is zero, this is similar to [`overflowing_mul`](Self::overflowing_mul),
3155        /// except that it gives the value of the overflow instead of just whether one happened:
3156        ///
3157        /// ```
3158        /// # #![allow(unused_features)]
3159        /// #![feature(const_unsigned_bigint_helpers)]
3160        /// let r = u8::carrying_mul(7, 13, 0);
3161        /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(7, 13));
3162        /// let r = u8::carrying_mul(13, 42, 0);
3163        /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(13, 42));
3164        /// ```
3165        ///
3166        /// The value of the first field in the returned tuple matches what you'd get
3167        /// by combining the [`wrapping_mul`](Self::wrapping_mul) and
3168        /// [`wrapping_add`](Self::wrapping_add) methods:
3169        ///
3170        /// ```
3171        /// # #![allow(unused_features)]
3172        /// #![feature(const_unsigned_bigint_helpers)]
3173        /// assert_eq!(
3174        ///     789_u16.carrying_mul(456, 123).0,
3175        ///     789_u16.wrapping_mul(456).wrapping_add(123),
3176        /// );
3177        /// ```
3178        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
3179        #[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
3180        #[must_use = "this returns the result of the operation, \
3181                      without modifying the original"]
3182        #[inline]
3183        pub const fn carrying_mul(self, rhs: Self, carry: Self) -> (Self, Self) {
3184            Self::carrying_mul_add(self, rhs, carry, 0)
3185        }
3186
3187        /// Calculates the "full multiplication" `self * rhs + carry + add`.
3188        ///
3189        /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
3190        /// of the result as two separate values, in that order.
3191        ///
3192        /// This cannot overflow, as the double-width result has exactly enough
3193        /// space for the largest possible result. This is equivalent to how, in
3194        /// decimal, 9 × 9 + 9 + 9 = 81 + 18 = 99 = 9×10⁰ + 9×10¹ = 10² - 1.
3195        ///
3196        /// Performs "long multiplication" which takes in an extra amount to add, and may return an
3197        /// additional amount of overflow. This allows for chaining together multiple
3198        /// multiplications to create "big integers" which represent larger values.
3199        ///
3200        /// If you don't need the `add` part, then you can use [`Self::carrying_mul`] instead.
3201        ///
3202        /// # Examples
3203        ///
3204        /// Please note that this example is shared between integer types,
3205        /// which explains why `u32` is used here.
3206        ///
3207        /// ```
3208        /// assert_eq!(5u32.carrying_mul_add(2, 0, 0), (10, 0));
3209        /// assert_eq!(5u32.carrying_mul_add(2, 10, 10), (30, 0));
3210        /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 0, 0), (1410065408, 2));
3211        /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 10, 10), (1410065428, 2));
3212        #[doc = concat!("assert_eq!(",
3213            stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
3214            "(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX));"
3215        )]
3216        /// ```
3217        ///
3218        /// This is the core per-digit operation for "grade school" O(n²) multiplication.
3219        ///
3220        /// Please note that this example is shared between integer types,
3221        /// using `u8` for simplicity of the demonstration.
3222        ///
3223        /// ```
3224        /// fn quadratic_mul<const N: usize>(a: [u8; N], b: [u8; N]) -> [u8; N] {
3225        ///     let mut out = [0; N];
3226        ///     for j in 0..N {
3227        ///         let mut carry = 0;
3228        ///         for i in 0..(N - j) {
3229        ///             (out[j + i], carry) = u8::carrying_mul_add(a[i], b[j], out[j + i], carry);
3230        ///         }
3231        ///     }
3232        ///     out
3233        /// }
3234        ///
3235        /// // -1 * -1 == 1
3236        /// assert_eq!(quadratic_mul([0xFF; 3], [0xFF; 3]), [1, 0, 0]);
3237        ///
3238        /// assert_eq!(u32::wrapping_mul(0x9e3779b9, 0x7f4a7c15), 0xcffc982d);
3239        /// assert_eq!(
3240        ///     quadratic_mul(u32::to_le_bytes(0x9e3779b9), u32::to_le_bytes(0x7f4a7c15)),
3241        ///     u32::to_le_bytes(0xcffc982d)
3242        /// );
3243        /// ```
3244        #[stable(feature = "unsigned_bigint_helpers", since = "1.91.0")]
3245        #[rustc_const_unstable(feature = "const_unsigned_bigint_helpers", issue = "152015")]
3246        #[must_use = "this returns the result of the operation, \
3247                      without modifying the original"]
3248        #[inline]
3249        pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> (Self, Self) {
3250            intrinsics::carrying_mul_add(self, rhs, carry, add)
3251        }
3252
3253        /// Calculates the divisor when `self` is divided by `rhs`.
3254        ///
3255        /// Returns a tuple of the divisor along with a boolean indicating
3256        /// whether an arithmetic overflow would occur. Note that for unsigned
3257        /// integers overflow never occurs, so the second value is always
3258        /// `false`.
3259        ///
3260        /// # Panics
3261        ///
3262        /// This function will panic if `rhs` is zero.
3263        ///
3264        /// # Examples
3265        ///
3266        /// ```
3267        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
3268        /// ```
3269        #[inline(always)]
3270        #[stable(feature = "wrapping", since = "1.7.0")]
3271        #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
3272        #[must_use = "this returns the result of the operation, \
3273                      without modifying the original"]
3274        #[track_caller]
3275        pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
3276            (self / rhs, false)
3277        }
3278
3279        /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`.
3280        ///
3281        /// Returns a tuple of the divisor along with a boolean indicating
3282        /// whether an arithmetic overflow would occur. Note that for unsigned
3283        /// integers overflow never occurs, so the second value is always
3284        /// `false`.
3285        /// Since, for the positive integers, all common
3286        /// definitions of division are equal, this
3287        /// is exactly equal to `self.overflowing_div(rhs)`.
3288        ///
3289        /// # Panics
3290        ///
3291        /// This function will panic if `rhs` is zero.
3292        ///
3293        /// # Examples
3294        ///
3295        /// ```
3296        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
3297        /// ```
3298        #[inline(always)]
3299        #[stable(feature = "euclidean_division", since = "1.38.0")]
3300        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3301        #[must_use = "this returns the result of the operation, \
3302                      without modifying the original"]
3303        #[track_caller]
3304        pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
3305            (self / rhs, false)
3306        }
3307
3308        /// Calculates the remainder when `self` is divided by `rhs`.
3309        ///
3310        /// Returns a tuple of the remainder after dividing along with a boolean
3311        /// indicating whether an arithmetic overflow would occur. Note that for
3312        /// unsigned integers overflow never occurs, so the second value is
3313        /// always `false`.
3314        ///
3315        /// # Panics
3316        ///
3317        /// This function will panic if `rhs` is zero.
3318        ///
3319        /// # Examples
3320        ///
3321        /// ```
3322        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
3323        /// ```
3324        #[inline(always)]
3325        #[stable(feature = "wrapping", since = "1.7.0")]
3326        #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
3327        #[must_use = "this returns the result of the operation, \
3328                      without modifying the original"]
3329        #[track_caller]
3330        pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
3331            (self % rhs, false)
3332        }
3333
3334        /// Calculates the remainder `self.rem_euclid(rhs)` as if by Euclidean division.
3335        ///
3336        /// Returns a tuple of the modulo after dividing along with a boolean
3337        /// indicating whether an arithmetic overflow would occur. Note that for
3338        /// unsigned integers overflow never occurs, so the second value is
3339        /// always `false`.
3340        /// Since, for the positive integers, all common
3341        /// definitions of division are equal, this operation
3342        /// is exactly equal to `self.overflowing_rem(rhs)`.
3343        ///
3344        /// # Panics
3345        ///
3346        /// This function will panic if `rhs` is zero.
3347        ///
3348        /// # Examples
3349        ///
3350        /// ```
3351        #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
3352        /// ```
3353        #[inline(always)]
3354        #[stable(feature = "euclidean_division", since = "1.38.0")]
3355        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3356        #[must_use = "this returns the result of the operation, \
3357                      without modifying the original"]
3358        #[track_caller]
3359        pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
3360            (self % rhs, false)
3361        }
3362
3363        /// Negates self in an overflowing fashion.
3364        ///
3365        /// Returns `!self + 1` using wrapping operations to return the value
3366        /// that represents the negation of this unsigned value. Note that for
3367        /// positive unsigned values overflow always occurs, but negating 0 does
3368        /// not overflow.
3369        ///
3370        /// # Examples
3371        ///
3372        /// ```
3373        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false));")]
3374        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), ", true));")]
3375        /// ```
3376        #[inline(always)]
3377        #[stable(feature = "wrapping", since = "1.7.0")]
3378        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3379        #[must_use = "this returns the result of the operation, \
3380                      without modifying the original"]
3381        pub const fn overflowing_neg(self) -> (Self, bool) {
3382            ((!self).wrapping_add(1), self != 0)
3383        }
3384
3385        /// Shifts self left by `rhs` bits.
3386        ///
3387        /// Returns a tuple of the shifted version of self along with a boolean
3388        /// indicating whether the shift value was larger than or equal to the
3389        /// number of bits. If the shift value is too large, then value is
3390        /// masked (N-1) where N is the number of bits, and this value is then
3391        /// used to perform the shift.
3392        ///
3393        /// # Examples
3394        ///
3395        /// ```
3396        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")]
3397        #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));")]
3398        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
3399        /// ```
3400        #[stable(feature = "wrapping", since = "1.7.0")]
3401        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3402        #[must_use = "this returns the result of the operation, \
3403                      without modifying the original"]
3404        #[inline(always)]
3405        pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
3406            (self.wrapping_shl(rhs), rhs >= Self::BITS)
3407        }
3408
3409        /// Shifts self right by `rhs` bits.
3410        ///
3411        /// Returns a tuple of the shifted version of self along with a boolean
3412        /// indicating whether the shift value was larger than or equal to the
3413        /// number of bits. If the shift value is too large, then value is
3414        /// masked (N-1) where N is the number of bits, and this value is then
3415        /// used to perform the shift.
3416        ///
3417        /// # Examples
3418        ///
3419        /// ```
3420        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
3421        #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));")]
3422        /// ```
3423        #[stable(feature = "wrapping", since = "1.7.0")]
3424        #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
3425        #[must_use = "this returns the result of the operation, \
3426                      without modifying the original"]
3427        #[inline(always)]
3428        pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
3429            (self.wrapping_shr(rhs), rhs >= Self::BITS)
3430        }
3431
3432        /// Raises self to the power of `exp`, using exponentiation by squaring.
3433        ///
3434        /// Returns a tuple of the exponentiation along with a bool indicating
3435        /// whether an overflow happened.
3436        ///
3437        /// # Examples
3438        ///
3439        /// ```
3440        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")]
3441        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".overflowing_pow(0), (1, false));")]
3442        /// assert_eq!(3u8.overflowing_pow(6), (217, true));
3443        /// ```
3444        #[stable(feature = "no_panic_pow", since = "1.34.0")]
3445        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3446        #[must_use = "this returns the result of the operation, \
3447                      without modifying the original"]
3448        #[inline]
3449        pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
3450            if exp == 0{
3451                return (1,false);
3452            }
3453            let mut base = self;
3454            let mut acc: Self = 1;
3455            let mut overflown = false;
3456            // Scratch space for storing results of overflowing_mul.
3457            let mut r;
3458
3459            loop {
3460                if (exp & 1) == 1 {
3461                    r = acc.overflowing_mul(base);
3462                    // since exp!=0, finally the exp must be 1.
3463                    if exp == 1 {
3464                        r.1 |= overflown;
3465                        return r;
3466                    }
3467                    acc = r.0;
3468                    overflown |= r.1;
3469                }
3470                exp /= 2;
3471                r = base.overflowing_mul(base);
3472                base = r.0;
3473                overflown |= r.1;
3474            }
3475        }
3476
3477        /// Raises self to the power of `exp`, using exponentiation by squaring.
3478        ///
3479        /// # Examples
3480        ///
3481        /// ```
3482        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")]
3483        #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".pow(0), 1);")]
3484        /// ```
3485        #[stable(feature = "rust1", since = "1.0.0")]
3486        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3487        #[must_use = "this returns the result of the operation, \
3488                      without modifying the original"]
3489        #[inline]
3490        #[rustc_inherit_overflow_checks]
3491        pub const fn pow(self, mut exp: u32) -> Self {
3492            if exp == 0 {
3493                return 1;
3494            }
3495            let mut base = self;
3496            let mut acc = 1;
3497
3498            if intrinsics::is_val_statically_known(exp) {
3499                while exp > 1 {
3500                    if (exp & 1) == 1 {
3501                        acc = acc * base;
3502                    }
3503                    exp /= 2;
3504                    base = base * base;
3505                }
3506
3507                // since exp!=0, finally the exp must be 1.
3508                // Deal with the final bit of the exponent separately, since
3509                // squaring the base afterwards is not necessary and may cause a
3510                // needless overflow.
3511                acc * base
3512            } else {
3513                // This is faster than the above when the exponent is not known
3514                // at compile time. We can't use the same code for the constant
3515                // exponent case because LLVM is currently unable to unroll
3516                // this loop.
3517                loop {
3518                    if (exp & 1) == 1 {
3519                        acc = acc * base;
3520                        // since exp!=0, finally the exp must be 1.
3521                        if exp == 1 {
3522                            return acc;
3523                        }
3524                    }
3525                    exp /= 2;
3526                    base = base * base;
3527                }
3528            }
3529        }
3530
3531        /// Returns the square root of the number, rounded down.
3532        ///
3533        /// # Examples
3534        ///
3535        /// ```
3536        #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
3537        /// ```
3538        #[stable(feature = "isqrt", since = "1.84.0")]
3539        #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
3540        #[must_use = "this returns the result of the operation, \
3541                      without modifying the original"]
3542        #[inline]
3543        pub const fn isqrt(self) -> Self {
3544            let result = crate::num::int_sqrt::$ActualT(self as $ActualT) as $SelfT;
3545
3546            // Inform the optimizer what the range of outputs is. If testing
3547            // `core` crashes with no panic message and a `num::int_sqrt::u*`
3548            // test failed, it's because your edits caused these assertions or
3549            // the assertions in `fn isqrt` of `nonzero.rs` to become false.
3550            //
3551            // SAFETY: Integer square root is a monotonically nondecreasing
3552            // function, which means that increasing the input will never
3553            // cause the output to decrease. Thus, since the input for unsigned
3554            // integers is bounded by `[0, <$ActualT>::MAX]`, sqrt(n) will be
3555            // bounded by `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
3556            unsafe {
3557                const MAX_RESULT: $SelfT = crate::num::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT;
3558                crate::hint::assert_unchecked(result <= MAX_RESULT);
3559            }
3560
3561            result
3562        }
3563
3564        /// Performs Euclidean division.
3565        ///
3566        /// Since, for the positive integers, all common
3567        /// definitions of division are equal, this
3568        /// is exactly equal to `self / rhs`.
3569        ///
3570        /// # Panics
3571        ///
3572        /// This function will panic if `rhs` is zero.
3573        ///
3574        /// # Examples
3575        ///
3576        /// ```
3577        #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")]
3578        /// ```
3579        #[stable(feature = "euclidean_division", since = "1.38.0")]
3580        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3581        #[must_use = "this returns the result of the operation, \
3582                      without modifying the original"]
3583        #[inline(always)]
3584        #[track_caller]
3585        pub const fn div_euclid(self, rhs: Self) -> Self {
3586            self / rhs
3587        }
3588
3589
3590        /// Calculates the least remainder of `self` when divided by
3591        /// `rhs`.
3592        ///
3593        /// Since, for the positive integers, all common
3594        /// definitions of division are equal, this
3595        /// is exactly equal to `self % rhs`.
3596        ///
3597        /// # Panics
3598        ///
3599        /// This function will panic if `rhs` is zero.
3600        ///
3601        /// # Examples
3602        ///
3603        /// ```
3604        #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type")]
3605        /// ```
3606        #[doc(alias = "modulo", alias = "mod")]
3607        #[stable(feature = "euclidean_division", since = "1.38.0")]
3608        #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3609        #[must_use = "this returns the result of the operation, \
3610                      without modifying the original"]
3611        #[inline(always)]
3612        #[track_caller]
3613        pub const fn rem_euclid(self, rhs: Self) -> Self {
3614            self % rhs
3615        }
3616
3617        /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
3618        ///
3619        /// This is the same as performing `self / rhs` for all unsigned integers.
3620        ///
3621        /// # Panics
3622        ///
3623        /// This function will panic if `rhs` is zero.
3624        ///
3625        /// # Examples
3626        ///
3627        /// ```
3628        /// #![feature(int_roundings)]
3629        #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")]
3630        /// ```
3631        #[unstable(feature = "int_roundings", issue = "88581")]
3632        #[must_use = "this returns the result of the operation, \
3633                      without modifying the original"]
3634        #[inline(always)]
3635        #[track_caller]
3636        pub const fn div_floor(self, rhs: Self) -> Self {
3637            self / rhs
3638        }
3639
3640        /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
3641        ///
3642        /// # Panics
3643        ///
3644        /// This function will panic if `rhs` is zero.
3645        ///
3646        /// # Examples
3647        ///
3648        /// ```
3649        #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")]
3650        /// ```
3651        #[stable(feature = "int_roundings1", since = "1.73.0")]
3652        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3653        #[must_use = "this returns the result of the operation, \
3654                      without modifying the original"]
3655        #[inline]
3656        #[track_caller]
3657        pub const fn div_ceil(self, rhs: Self) -> Self {
3658            let d = self / rhs;
3659            let r = self % rhs;
3660            if r > 0 {
3661                d + 1
3662            } else {
3663                d
3664            }
3665        }
3666
3667        /// Calculates the smallest value greater than or equal to `self` that
3668        /// is a multiple of `rhs`.
3669        ///
3670        /// # Panics
3671        ///
3672        /// This function will panic if `rhs` is zero.
3673        ///
3674        /// ## Overflow behavior
3675        ///
3676        /// On overflow, this function will panic if overflow checks are enabled (default in debug
3677        /// mode) and wrap if overflow checks are disabled (default in release mode).
3678        ///
3679        /// # Examples
3680        ///
3681        /// ```
3682        #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
3683        #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
3684        /// ```
3685        #[stable(feature = "int_roundings1", since = "1.73.0")]
3686        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3687        #[must_use = "this returns the result of the operation, \
3688                      without modifying the original"]
3689        #[inline]
3690        #[rustc_inherit_overflow_checks]
3691        pub const fn next_multiple_of(self, rhs: Self) -> Self {
3692            match self % rhs {
3693                0 => self,
3694                r => self + (rhs - r)
3695            }
3696        }
3697
3698        /// Calculates the smallest value greater than or equal to `self` that
3699        /// is a multiple of `rhs`. Returns `None` if `rhs` is zero or the
3700        /// operation would result in overflow.
3701        ///
3702        /// # Examples
3703        ///
3704        /// ```
3705        #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
3706        #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
3707        #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
3708        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
3709        /// ```
3710        #[stable(feature = "int_roundings1", since = "1.73.0")]
3711        #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3712        #[must_use = "this returns the result of the operation, \
3713                      without modifying the original"]
3714        #[inline]
3715        pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
3716            match try_opt!(self.checked_rem(rhs)) {
3717                0 => Some(self),
3718                // rhs - r cannot overflow because r is smaller than rhs
3719                r => self.checked_add(rhs - r)
3720            }
3721        }
3722
3723        /// Returns `true` if `self` is an integer multiple of `rhs`, and false otherwise.
3724        ///
3725        /// This function is equivalent to `self % rhs == 0`, except that it will not panic
3726        /// for `rhs == 0`. Instead, `0.is_multiple_of(0) == true`, and for any non-zero `n`,
3727        /// `n.is_multiple_of(0) == false`.
3728        ///
3729        /// # Examples
3730        ///
3731        /// ```
3732        #[doc = concat!("assert!(6_", stringify!($SelfT), ".is_multiple_of(2));")]
3733        #[doc = concat!("assert!(!5_", stringify!($SelfT), ".is_multiple_of(2));")]
3734        ///
3735        #[doc = concat!("assert!(0_", stringify!($SelfT), ".is_multiple_of(0));")]
3736        #[doc = concat!("assert!(!6_", stringify!($SelfT), ".is_multiple_of(0));")]
3737        /// ```
3738        #[stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
3739        #[rustc_const_stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
3740        #[must_use]
3741        #[inline]
3742        pub const fn is_multiple_of(self, rhs: Self) -> bool {
3743            match rhs {
3744                0 => self == 0,
3745                _ => self % rhs == 0,
3746            }
3747        }
3748
3749        /// Returns `true` if and only if `self == 2^k` for some unsigned integer `k`.
3750        ///
3751        /// # Examples
3752        ///
3753        /// ```
3754        #[doc = concat!("assert!(16", stringify!($SelfT), ".is_power_of_two());")]
3755        #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_power_of_two());")]
3756        /// ```
3757        #[must_use]
3758        #[stable(feature = "rust1", since = "1.0.0")]
3759        #[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")]
3760        #[inline(always)]
3761        pub const fn is_power_of_two(self) -> bool {
3762            self.count_ones() == 1
3763        }
3764
3765        // Returns one less than next power of two.
3766        // (For 8u8 next power of two is 8u8 and for 6u8 it is 8u8)
3767        //
3768        // 8u8.one_less_than_next_power_of_two() == 7
3769        // 6u8.one_less_than_next_power_of_two() == 7
3770        //
3771        // This method cannot overflow, as in the `next_power_of_two`
3772        // overflow cases it instead ends up returning the maximum value
3773        // of the type, and can return 0 for 0.
3774        #[inline]
3775        const fn one_less_than_next_power_of_two(self) -> Self {
3776            if self <= 1 { return 0; }
3777
3778            let p = self - 1;
3779            // SAFETY: Because `p > 0`, it cannot consist entirely of leading zeros.
3780            // That means the shift is always in-bounds, and some processors
3781            // (such as intel pre-haswell) have more efficient ctlz
3782            // intrinsics when the argument is non-zero.
3783            let z = unsafe { intrinsics::ctlz_nonzero(p) };
3784            <$SelfT>::MAX >> z
3785        }
3786
3787        /// Returns the smallest power of two greater than or equal to `self`.
3788        ///
3789        /// When return value overflows (i.e., `self > (1 << (N-1))` for type
3790        /// `uN`), it panics in debug mode and the return value is wrapped to 0 in
3791        /// release mode (the only situation in which this method can return 0).
3792        ///
3793        /// # Examples
3794        ///
3795        /// ```
3796        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")]
3797        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")]
3798        #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".next_power_of_two(), 1);")]
3799        /// ```
3800        #[stable(feature = "rust1", since = "1.0.0")]
3801        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3802        #[must_use = "this returns the result of the operation, \
3803                      without modifying the original"]
3804        #[inline]
3805        #[rustc_inherit_overflow_checks]
3806        pub const fn next_power_of_two(self) -> Self {
3807            self.one_less_than_next_power_of_two() + 1
3808        }
3809
3810        /// Returns the smallest power of two greater than or equal to `self`. If
3811        /// the next power of two is greater than the type's maximum value,
3812        /// `None` is returned, otherwise the power of two is wrapped in `Some`.
3813        ///
3814        /// # Examples
3815        ///
3816        /// ```
3817        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_next_power_of_two(), Some(2));")]
3818        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));")]
3819        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);")]
3820        /// ```
3821        #[inline]
3822        #[stable(feature = "rust1", since = "1.0.0")]
3823        #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3824        #[must_use = "this returns the result of the operation, \
3825                      without modifying the original"]
3826        pub const fn checked_next_power_of_two(self) -> Option<Self> {
3827            self.one_less_than_next_power_of_two().checked_add(1)
3828        }
3829
3830        /// Returns the smallest power of two greater than or equal to `n`. If
3831        /// the next power of two is greater than the type's maximum value,
3832        /// the return value is wrapped to `0`.
3833        ///
3834        /// # Examples
3835        ///
3836        /// ```
3837        /// #![feature(wrapping_next_power_of_two)]
3838        ///
3839        #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);")]
3840        #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);")]
3841        #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);")]
3842        /// ```
3843        #[inline]
3844        #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
3845                   reason = "needs decision on wrapping behavior")]
3846        #[must_use = "this returns the result of the operation, \
3847                      without modifying the original"]
3848        pub const fn wrapping_next_power_of_two(self) -> Self {
3849            self.one_less_than_next_power_of_two().wrapping_add(1)
3850        }
3851
3852        /// Returns the memory representation of this integer as a byte array in
3853        /// big-endian (network) byte order.
3854        ///
3855        #[doc = $to_xe_bytes_doc]
3856        ///
3857        /// # Examples
3858        ///
3859        /// ```
3860        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
3861        #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
3862        /// ```
3863        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3864        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3865        #[must_use = "this returns the result of the operation, \
3866                      without modifying the original"]
3867        #[inline]
3868        pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] {
3869            self.to_be().to_ne_bytes()
3870        }
3871
3872        /// Returns the memory representation of this integer as a byte array in
3873        /// little-endian byte order.
3874        ///
3875        #[doc = $to_xe_bytes_doc]
3876        ///
3877        /// # Examples
3878        ///
3879        /// ```
3880        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
3881        #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
3882        /// ```
3883        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3884        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3885        #[must_use = "this returns the result of the operation, \
3886                      without modifying the original"]
3887        #[inline]
3888        pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] {
3889            self.to_le().to_ne_bytes()
3890        }
3891
3892        /// Returns the memory representation of this integer as a byte array in
3893        /// native byte order.
3894        ///
3895        /// As the target platform's native endianness is used, portable code
3896        /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
3897        /// instead.
3898        ///
3899        #[doc = $to_xe_bytes_doc]
3900        ///
3901        /// [`to_be_bytes`]: Self::to_be_bytes
3902        /// [`to_le_bytes`]: Self::to_le_bytes
3903        ///
3904        /// # Examples
3905        ///
3906        /// ```
3907        #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
3908        /// assert_eq!(
3909        ///     bytes,
3910        ///     if cfg!(target_endian = "big") {
3911        #[doc = concat!("        ", $be_bytes)]
3912        ///     } else {
3913        #[doc = concat!("        ", $le_bytes)]
3914        ///     }
3915        /// );
3916        /// ```
3917        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3918        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3919        #[must_use = "this returns the result of the operation, \
3920                      without modifying the original"]
3921        #[allow(unnecessary_transmutes)]
3922        // SAFETY: const sound because integers are plain old datatypes so we can always
3923        // transmute them to arrays of bytes
3924        #[inline]
3925        pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] {
3926            // SAFETY: integers are plain old datatypes so we can always transmute them to
3927            // arrays of bytes
3928            unsafe { mem::transmute(self) }
3929        }
3930
3931        /// Creates a native endian integer value from its representation
3932        /// as a byte array in big endian.
3933        ///
3934        #[doc = $from_xe_bytes_doc]
3935        ///
3936        /// # Examples
3937        ///
3938        /// ```
3939        #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
3940        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3941        /// ```
3942        ///
3943        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3944        ///
3945        /// ```
3946        #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3947        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3948        ///     *input = rest;
3949        #[doc = concat!("    ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
3950        /// }
3951        /// ```
3952        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3953        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3954        #[must_use]
3955        #[inline]
3956        pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3957            Self::from_be(Self::from_ne_bytes(bytes))
3958        }
3959
3960        /// Creates a native endian integer value from its representation
3961        /// as a byte array in little endian.
3962        ///
3963        #[doc = $from_xe_bytes_doc]
3964        ///
3965        /// # Examples
3966        ///
3967        /// ```
3968        #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
3969        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3970        /// ```
3971        ///
3972        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3973        ///
3974        /// ```
3975        #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3976        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3977        ///     *input = rest;
3978        #[doc = concat!("    ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
3979        /// }
3980        /// ```
3981        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3982        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3983        #[must_use]
3984        #[inline]
3985        pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3986            Self::from_le(Self::from_ne_bytes(bytes))
3987        }
3988
3989        /// Creates a native endian integer value from its memory representation
3990        /// as a byte array in native endianness.
3991        ///
3992        /// As the target platform's native endianness is used, portable code
3993        /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
3994        /// appropriate instead.
3995        ///
3996        /// [`from_be_bytes`]: Self::from_be_bytes
3997        /// [`from_le_bytes`]: Self::from_le_bytes
3998        ///
3999        #[doc = $from_xe_bytes_doc]
4000        ///
4001        /// # Examples
4002        ///
4003        /// ```
4004        #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
4005        #[doc = concat!("    ", $be_bytes, "")]
4006        /// } else {
4007        #[doc = concat!("    ", $le_bytes, "")]
4008        /// });
4009        #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
4010        /// ```
4011        ///
4012        /// When starting from a slice rather than an array, fallible conversion APIs can be used:
4013        ///
4014        /// ```
4015        #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
4016        #[doc = concat!("    let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
4017        ///     *input = rest;
4018        #[doc = concat!("    ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
4019        /// }
4020        /// ```
4021        #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
4022        #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
4023        #[allow(unnecessary_transmutes)]
4024        #[must_use]
4025        // SAFETY: const sound because integers are plain old datatypes so we can always
4026        // transmute to them
4027        #[inline]
4028        pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
4029            // SAFETY: integers are plain old datatypes so we can always transmute to them
4030            unsafe { mem::transmute(bytes) }
4031        }
4032
4033        /// New code should prefer to use
4034        #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
4035        ///
4036        /// Returns the smallest value that can be represented by this integer type.
4037        #[stable(feature = "rust1", since = "1.0.0")]
4038        #[rustc_promotable]
4039        #[inline(always)]
4040        #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
4041        #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
4042        #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
4043        pub const fn min_value() -> Self { Self::MIN }
4044
4045        /// New code should prefer to use
4046        #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
4047        ///
4048        /// Returns the largest value that can be represented by this integer type.
4049        #[stable(feature = "rust1", since = "1.0.0")]
4050        #[rustc_promotable]
4051        #[inline(always)]
4052        #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
4053        #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
4054        #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
4055        pub const fn max_value() -> Self { Self::MAX }
4056    }
4057}