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 swap_op = $swap_op:literal,
18 swapped = $swapped:literal,
19 reversed = $reversed:literal,
20 le_bytes = $le_bytes:literal,
21 be_bytes = $be_bytes:literal,
22 to_xe_bytes_doc = $to_xe_bytes_doc:expr,
23 from_xe_bytes_doc = $from_xe_bytes_doc:expr,
24 bound_condition = $bound_condition:literal,
25 ) => {
26 /// The smallest value that can be represented by this integer type.
27 ///
28 /// # Examples
29 ///
30 /// ```
31 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, 0);")]
32 /// ```
33 #[stable(feature = "assoc_int_consts", since = "1.43.0")]
34 pub const MIN: Self = 0;
35
36 /// The largest value that can be represented by this integer type
37 #[doc = concat!("(2<sup>", $BITS, "</sup> − 1", $bound_condition, ").")]
38 ///
39 /// # Examples
40 ///
41 /// ```
42 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");")]
43 /// ```
44 #[stable(feature = "assoc_int_consts", since = "1.43.0")]
45 pub const MAX: Self = !0;
46
47 /// The size of this integer type in bits.
48 ///
49 /// # Examples
50 ///
51 /// ```
52 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
53 /// ```
54 #[stable(feature = "int_bits_const", since = "1.53.0")]
55 pub const BITS: u32 = Self::MAX.count_ones();
56
57 /// Returns the number of ones in the binary representation of `self`.
58 ///
59 /// # Examples
60 ///
61 /// ```
62 #[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")]
63 /// assert_eq!(n.count_ones(), 3);
64 ///
65 #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
66 #[doc = concat!("assert_eq!(max.count_ones(), ", stringify!($BITS), ");")]
67 ///
68 #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
69 /// assert_eq!(zero.count_ones(), 0);
70 /// ```
71 #[stable(feature = "rust1", since = "1.0.0")]
72 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
73 #[doc(alias = "popcount")]
74 #[doc(alias = "popcnt")]
75 #[must_use = "this returns the result of the operation, \
76 without modifying the original"]
77 #[inline(always)]
78 pub const fn count_ones(self) -> u32 {
79 return intrinsics::ctpop(self);
80 }
81
82 /// Returns the number of zeros in the binary representation of `self`.
83 ///
84 /// # Examples
85 ///
86 /// ```
87 #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
88 #[doc = concat!("assert_eq!(zero.count_zeros(), ", stringify!($BITS), ");")]
89 ///
90 #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
91 /// assert_eq!(max.count_zeros(), 0);
92 /// ```
93 #[stable(feature = "rust1", since = "1.0.0")]
94 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
95 #[must_use = "this returns the result of the operation, \
96 without modifying the original"]
97 #[inline(always)]
98 pub const fn count_zeros(self) -> u32 {
99 (!self).count_ones()
100 }
101
102 /// Returns the number of leading zeros in the binary representation of `self`.
103 ///
104 /// Depending on what you're doing with the value, you might also be interested in the
105 /// [`ilog2`] function which returns a consistent number, even if the type widens.
106 ///
107 /// # Examples
108 ///
109 /// ```
110 #[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")]
111 /// assert_eq!(n.leading_zeros(), 2);
112 ///
113 #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
114 #[doc = concat!("assert_eq!(zero.leading_zeros(), ", stringify!($BITS), ");")]
115 ///
116 #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
117 /// assert_eq!(max.leading_zeros(), 0);
118 /// ```
119 #[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")]
120 #[stable(feature = "rust1", since = "1.0.0")]
121 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
122 #[must_use = "this returns the result of the operation, \
123 without modifying the original"]
124 #[inline(always)]
125 pub const fn leading_zeros(self) -> u32 {
126 return intrinsics::ctlz(self as $ActualT);
127 }
128
129 /// Returns the number of trailing zeros in the binary representation
130 /// of `self`.
131 ///
132 /// # Examples
133 ///
134 /// ```
135 #[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")]
136 /// assert_eq!(n.trailing_zeros(), 3);
137 ///
138 #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
139 #[doc = concat!("assert_eq!(zero.trailing_zeros(), ", stringify!($BITS), ");")]
140 ///
141 #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
142 #[doc = concat!("assert_eq!(max.trailing_zeros(), 0);")]
143 /// ```
144 #[stable(feature = "rust1", since = "1.0.0")]
145 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
146 #[must_use = "this returns the result of the operation, \
147 without modifying the original"]
148 #[inline(always)]
149 pub const fn trailing_zeros(self) -> u32 {
150 return intrinsics::cttz(self);
151 }
152
153 /// Returns the number of leading ones in the binary representation of `self`.
154 ///
155 /// # Examples
156 ///
157 /// ```
158 #[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")]
159 /// assert_eq!(n.leading_ones(), 2);
160 ///
161 #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
162 /// assert_eq!(zero.leading_ones(), 0);
163 ///
164 #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
165 #[doc = concat!("assert_eq!(max.leading_ones(), ", stringify!($BITS), ");")]
166 /// ```
167 #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
168 #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
169 #[must_use = "this returns the result of the operation, \
170 without modifying the original"]
171 #[inline(always)]
172 pub const fn leading_ones(self) -> u32 {
173 (!self).leading_zeros()
174 }
175
176 /// Returns the number of trailing ones in the binary representation
177 /// of `self`.
178 ///
179 /// # Examples
180 ///
181 /// ```
182 #[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")]
183 /// assert_eq!(n.trailing_ones(), 3);
184 ///
185 #[doc = concat!("let zero = 0", stringify!($SelfT), ";")]
186 /// assert_eq!(zero.trailing_ones(), 0);
187 ///
188 #[doc = concat!("let max = ", stringify!($SelfT),"::MAX;")]
189 #[doc = concat!("assert_eq!(max.trailing_ones(), ", stringify!($BITS), ");")]
190 /// ```
191 #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
192 #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
193 #[must_use = "this returns the result of the operation, \
194 without modifying the original"]
195 #[inline(always)]
196 pub const fn trailing_ones(self) -> u32 {
197 (!self).trailing_zeros()
198 }
199
200 /// Returns the minimum number of bits required to represent `self`.
201 ///
202 /// This method returns zero if `self` is zero.
203 ///
204 /// # Examples
205 ///
206 /// ```
207 /// #![feature(uint_bit_width)]
208 ///
209 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".bit_width(), 0);")]
210 #[doc = concat!("assert_eq!(0b111_", stringify!($SelfT), ".bit_width(), 3);")]
211 #[doc = concat!("assert_eq!(0b1110_", stringify!($SelfT), ".bit_width(), 4);")]
212 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.bit_width(), ", stringify!($BITS), ");")]
213 /// ```
214 #[unstable(feature = "uint_bit_width", issue = "142326")]
215 #[must_use = "this returns the result of the operation, \
216 without modifying the original"]
217 #[inline(always)]
218 pub const fn bit_width(self) -> u32 {
219 Self::BITS - self.leading_zeros()
220 }
221
222 /// Returns `self` with only the most significant bit set, or `0` if
223 /// the input is `0`.
224 ///
225 /// # Examples
226 ///
227 /// ```
228 /// #![feature(isolate_most_least_significant_one)]
229 ///
230 #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
231 ///
232 /// assert_eq!(n.isolate_highest_one(), 0b_01000000);
233 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_highest_one(), 0);")]
234 /// ```
235 #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
236 #[must_use = "this returns the result of the operation, \
237 without modifying the original"]
238 #[inline(always)]
239 pub const fn isolate_highest_one(self) -> Self {
240 self & (((1 as $SelfT) << (<$SelfT>::BITS - 1)).wrapping_shr(self.leading_zeros()))
241 }
242
243 /// Returns `self` with only the least significant bit set, or `0` if
244 /// the input is `0`.
245 ///
246 /// # Examples
247 ///
248 /// ```
249 /// #![feature(isolate_most_least_significant_one)]
250 ///
251 #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
252 ///
253 /// assert_eq!(n.isolate_lowest_one(), 0b_00000100);
254 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_lowest_one(), 0);")]
255 /// ```
256 #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
257 #[must_use = "this returns the result of the operation, \
258 without modifying the original"]
259 #[inline(always)]
260 pub const fn isolate_lowest_one(self) -> Self {
261 self & self.wrapping_neg()
262 }
263
264 /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
265 ///
266 /// This produces the same result as an `as` cast, but ensures that the bit-width remains
267 /// the same.
268 ///
269 /// # Examples
270 ///
271 /// ```
272 #[doc = concat!("let n = ", stringify!($SelfT), "::MAX;")]
273 ///
274 #[doc = concat!("assert_eq!(n.cast_signed(), -1", stringify!($SignedT), ");")]
275 /// ```
276 #[stable(feature = "integer_sign_cast", since = "1.87.0")]
277 #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
278 #[must_use = "this returns the result of the operation, \
279 without modifying the original"]
280 #[inline(always)]
281 pub const fn cast_signed(self) -> $SignedT {
282 self as $SignedT
283 }
284
285 /// Shifts the bits to the left by a specified amount, `n`,
286 /// wrapping the truncated bits to the end of the resulting integer.
287 ///
288 /// Please note this isn't the same operation as the `<<` shifting operator!
289 ///
290 /// # Examples
291 ///
292 /// ```
293 #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
294 #[doc = concat!("let m = ", $rot_result, ";")]
295 ///
296 #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
297 /// ```
298 #[stable(feature = "rust1", since = "1.0.0")]
299 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
300 #[must_use = "this returns the result of the operation, \
301 without modifying the original"]
302 #[inline(always)]
303 pub const fn rotate_left(self, n: u32) -> Self {
304 return intrinsics::rotate_left(self, n);
305 }
306
307 /// Shifts the bits to the right by a specified amount, `n`,
308 /// wrapping the truncated bits to the beginning of the resulting
309 /// integer.
310 ///
311 /// Please note this isn't the same operation as the `>>` shifting operator!
312 ///
313 /// # Examples
314 ///
315 /// ```
316 #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
317 #[doc = concat!("let m = ", $rot_op, ";")]
318 ///
319 #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
320 /// ```
321 #[stable(feature = "rust1", since = "1.0.0")]
322 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
323 #[must_use = "this returns the result of the operation, \
324 without modifying the original"]
325 #[inline(always)]
326 pub const fn rotate_right(self, n: u32) -> Self {
327 return intrinsics::rotate_right(self, n);
328 }
329
330 /// Reverses the byte order of the integer.
331 ///
332 /// # Examples
333 ///
334 /// ```
335 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
336 /// let m = n.swap_bytes();
337 ///
338 #[doc = concat!("assert_eq!(m, ", $swapped, ");")]
339 /// ```
340 #[stable(feature = "rust1", since = "1.0.0")]
341 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
342 #[must_use = "this returns the result of the operation, \
343 without modifying the original"]
344 #[inline(always)]
345 pub const fn swap_bytes(self) -> Self {
346 intrinsics::bswap(self as $ActualT) as Self
347 }
348
349 /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
350 /// second least-significant bit becomes second most-significant bit, etc.
351 ///
352 /// # Examples
353 ///
354 /// ```
355 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
356 /// let m = n.reverse_bits();
357 ///
358 #[doc = concat!("assert_eq!(m, ", $reversed, ");")]
359 #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
360 /// ```
361 #[stable(feature = "reverse_bits", since = "1.37.0")]
362 #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
363 #[must_use = "this returns the result of the operation, \
364 without modifying the original"]
365 #[inline(always)]
366 pub const fn reverse_bits(self) -> Self {
367 intrinsics::bitreverse(self as $ActualT) as Self
368 }
369
370 /// Converts an integer from big endian to the target's endianness.
371 ///
372 /// On big endian this is a no-op. On little endian the bytes are
373 /// swapped.
374 ///
375 /// # Examples
376 ///
377 /// ```
378 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
379 ///
380 /// if cfg!(target_endian = "big") {
381 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
382 /// } else {
383 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
384 /// }
385 /// ```
386 #[stable(feature = "rust1", since = "1.0.0")]
387 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
388 #[must_use]
389 #[inline(always)]
390 pub const fn from_be(x: Self) -> Self {
391 #[cfg(target_endian = "big")]
392 {
393 x
394 }
395 #[cfg(not(target_endian = "big"))]
396 {
397 x.swap_bytes()
398 }
399 }
400
401 /// Converts an integer from little endian to the target's endianness.
402 ///
403 /// On little endian this is a no-op. On big endian the bytes are
404 /// swapped.
405 ///
406 /// # Examples
407 ///
408 /// ```
409 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
410 ///
411 /// if cfg!(target_endian = "little") {
412 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
413 /// } else {
414 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
415 /// }
416 /// ```
417 #[stable(feature = "rust1", since = "1.0.0")]
418 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
419 #[must_use]
420 #[inline(always)]
421 pub const fn from_le(x: Self) -> Self {
422 #[cfg(target_endian = "little")]
423 {
424 x
425 }
426 #[cfg(not(target_endian = "little"))]
427 {
428 x.swap_bytes()
429 }
430 }
431
432 /// Converts `self` to big endian from the target's endianness.
433 ///
434 /// On big endian this is a no-op. On little endian the bytes are
435 /// swapped.
436 ///
437 /// # Examples
438 ///
439 /// ```
440 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
441 ///
442 /// if cfg!(target_endian = "big") {
443 /// assert_eq!(n.to_be(), n)
444 /// } else {
445 /// assert_eq!(n.to_be(), n.swap_bytes())
446 /// }
447 /// ```
448 #[stable(feature = "rust1", since = "1.0.0")]
449 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
450 #[must_use = "this returns the result of the operation, \
451 without modifying the original"]
452 #[inline(always)]
453 pub const fn to_be(self) -> Self { // or not to be?
454 #[cfg(target_endian = "big")]
455 {
456 self
457 }
458 #[cfg(not(target_endian = "big"))]
459 {
460 self.swap_bytes()
461 }
462 }
463
464 /// Converts `self` to little endian from the target's endianness.
465 ///
466 /// On little endian this is a no-op. On big endian the bytes are
467 /// swapped.
468 ///
469 /// # Examples
470 ///
471 /// ```
472 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
473 ///
474 /// if cfg!(target_endian = "little") {
475 /// assert_eq!(n.to_le(), n)
476 /// } else {
477 /// assert_eq!(n.to_le(), n.swap_bytes())
478 /// }
479 /// ```
480 #[stable(feature = "rust1", since = "1.0.0")]
481 #[rustc_const_stable(feature = "const_math", since = "1.32.0")]
482 #[must_use = "this returns the result of the operation, \
483 without modifying the original"]
484 #[inline(always)]
485 pub const fn to_le(self) -> Self {
486 #[cfg(target_endian = "little")]
487 {
488 self
489 }
490 #[cfg(not(target_endian = "little"))]
491 {
492 self.swap_bytes()
493 }
494 }
495
496 /// Checked integer addition. Computes `self + rhs`, returning `None`
497 /// if overflow occurred.
498 ///
499 /// # Examples
500 ///
501 /// ```
502 #[doc = concat!(
503 "assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ",
504 "Some(", stringify!($SelfT), "::MAX - 1));"
505 )]
506 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
507 /// ```
508 #[stable(feature = "rust1", since = "1.0.0")]
509 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
510 #[must_use = "this returns the result of the operation, \
511 without modifying the original"]
512 #[inline]
513 pub const fn checked_add(self, rhs: Self) -> Option<Self> {
514 // This used to use `overflowing_add`, but that means it ends up being
515 // a `wrapping_add`, losing some optimization opportunities. Notably,
516 // phrasing it this way helps `.checked_add(1)` optimize to a check
517 // against `MAX` and a `add nuw`.
518 // Per <https://github.com/rust-lang/rust/pull/124114#issuecomment-2066173305>,
519 // LLVM is happy to re-form the intrinsic later if useful.
520
521 if intrinsics::unlikely(intrinsics::add_with_overflow(self, rhs).1) {
522 None
523 } else {
524 // SAFETY: Just checked it doesn't overflow
525 Some(unsafe { intrinsics::unchecked_add(self, rhs) })
526 }
527 }
528
529 /// Strict integer addition. Computes `self + rhs`, panicking
530 /// if overflow occurred.
531 ///
532 /// # Panics
533 ///
534 /// ## Overflow behavior
535 ///
536 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
537 ///
538 /// # Examples
539 ///
540 /// ```
541 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
542 /// ```
543 ///
544 /// The following panics because of overflow:
545 ///
546 /// ```should_panic
547 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
548 /// ```
549 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
550 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
551 #[must_use = "this returns the result of the operation, \
552 without modifying the original"]
553 #[inline]
554 #[track_caller]
555 pub const fn strict_add(self, rhs: Self) -> Self {
556 let (a, b) = self.overflowing_add(rhs);
557 if b { overflow_panic::add() } else { a }
558 }
559
560 /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
561 /// cannot occur.
562 ///
563 /// Calling `x.unchecked_add(y)` is semantically equivalent to calling
564 /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
565 ///
566 /// If you're just trying to avoid the panic in debug mode, then **do not**
567 /// use this. Instead, you're looking for [`wrapping_add`].
568 ///
569 /// # Safety
570 ///
571 /// This results in undefined behavior when
572 #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
573 /// i.e. when [`checked_add`] would return `None`.
574 ///
575 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
576 #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
577 #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
578 #[stable(feature = "unchecked_math", since = "1.79.0")]
579 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
580 #[must_use = "this returns the result of the operation, \
581 without modifying the original"]
582 #[inline(always)]
583 #[track_caller]
584 pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
585 assert_unsafe_precondition!(
586 check_language_ub,
587 concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
588 (
589 lhs: $SelfT = self,
590 rhs: $SelfT = rhs,
591 ) => !lhs.overflowing_add(rhs).1,
592 );
593
594 // SAFETY: this is guaranteed to be safe by the caller.
595 unsafe {
596 intrinsics::unchecked_add(self, rhs)
597 }
598 }
599
600 /// Checked addition with a signed integer. Computes `self + rhs`,
601 /// returning `None` if overflow occurred.
602 ///
603 /// # Examples
604 ///
605 /// ```
606 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")]
607 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")]
608 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")]
609 /// ```
610 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
611 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
612 #[must_use = "this returns the result of the operation, \
613 without modifying the original"]
614 #[inline]
615 pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
616 let (a, b) = self.overflowing_add_signed(rhs);
617 if intrinsics::unlikely(b) { None } else { Some(a) }
618 }
619
620 /// Strict addition with a signed integer. Computes `self + rhs`,
621 /// panicking if overflow occurred.
622 ///
623 /// # Panics
624 ///
625 /// ## Overflow behavior
626 ///
627 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
628 ///
629 /// # Examples
630 ///
631 /// ```
632 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_signed(2), 3);")]
633 /// ```
634 ///
635 /// The following panic because of overflow:
636 ///
637 /// ```should_panic
638 #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_add_signed(-2);")]
639 /// ```
640 ///
641 /// ```should_panic
642 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_signed(3);")]
643 /// ```
644 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
645 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
646 #[must_use = "this returns the result of the operation, \
647 without modifying the original"]
648 #[inline]
649 #[track_caller]
650 pub const fn strict_add_signed(self, rhs: $SignedT) -> Self {
651 let (a, b) = self.overflowing_add_signed(rhs);
652 if b { overflow_panic::add() } else { a }
653 }
654
655 /// Checked integer subtraction. Computes `self - rhs`, returning
656 /// `None` if overflow occurred.
657 ///
658 /// # Examples
659 ///
660 /// ```
661 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")]
662 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")]
663 /// ```
664 #[stable(feature = "rust1", since = "1.0.0")]
665 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
666 #[must_use = "this returns the result of the operation, \
667 without modifying the original"]
668 #[inline]
669 pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
670 // Per PR#103299, there's no advantage to the `overflowing` intrinsic
671 // for *unsigned* subtraction and we just emit the manual check anyway.
672 // Thus, rather than using `overflowing_sub` that produces a wrapping
673 // subtraction, check it ourself so we can use an unchecked one.
674
675 if self < rhs {
676 None
677 } else {
678 // SAFETY: just checked this can't overflow
679 Some(unsafe { intrinsics::unchecked_sub(self, rhs) })
680 }
681 }
682
683 /// Strict integer subtraction. Computes `self - rhs`, panicking if
684 /// overflow occurred.
685 ///
686 /// # Panics
687 ///
688 /// ## Overflow behavior
689 ///
690 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
691 ///
692 /// # Examples
693 ///
694 /// ```
695 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub(1), 0);")]
696 /// ```
697 ///
698 /// The following panics because of overflow:
699 ///
700 /// ```should_panic
701 #[doc = concat!("let _ = 0", stringify!($SelfT), ".strict_sub(1);")]
702 /// ```
703 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
704 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
705 #[must_use = "this returns the result of the operation, \
706 without modifying the original"]
707 #[inline]
708 #[track_caller]
709 pub const fn strict_sub(self, rhs: Self) -> Self {
710 let (a, b) = self.overflowing_sub(rhs);
711 if b { overflow_panic::sub() } else { a }
712 }
713
714 /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
715 /// cannot occur.
716 ///
717 /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
718 /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
719 ///
720 /// If you're just trying to avoid the panic in debug mode, then **do not**
721 /// use this. Instead, you're looking for [`wrapping_sub`].
722 ///
723 /// If you find yourself writing code like this:
724 ///
725 /// ```
726 /// # let foo = 30_u32;
727 /// # let bar = 20;
728 /// if foo >= bar {
729 /// // SAFETY: just checked it will not overflow
730 /// let diff = unsafe { foo.unchecked_sub(bar) };
731 /// // ... use diff ...
732 /// }
733 /// ```
734 ///
735 /// Consider changing it to
736 ///
737 /// ```
738 /// # let foo = 30_u32;
739 /// # let bar = 20;
740 /// if let Some(diff) = foo.checked_sub(bar) {
741 /// // ... use diff ...
742 /// }
743 /// ```
744 ///
745 /// As that does exactly the same thing -- including telling the optimizer
746 /// that the subtraction cannot overflow -- but avoids needing `unsafe`.
747 ///
748 /// # Safety
749 ///
750 /// This results in undefined behavior when
751 #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
752 /// i.e. when [`checked_sub`] would return `None`.
753 ///
754 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
755 #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
756 #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
757 #[stable(feature = "unchecked_math", since = "1.79.0")]
758 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
759 #[must_use = "this returns the result of the operation, \
760 without modifying the original"]
761 #[inline(always)]
762 #[track_caller]
763 pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
764 assert_unsafe_precondition!(
765 check_language_ub,
766 concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
767 (
768 lhs: $SelfT = self,
769 rhs: $SelfT = rhs,
770 ) => !lhs.overflowing_sub(rhs).1,
771 );
772
773 // SAFETY: this is guaranteed to be safe by the caller.
774 unsafe {
775 intrinsics::unchecked_sub(self, rhs)
776 }
777 }
778
779 /// Checked subtraction with a signed integer. Computes `self - rhs`,
780 /// returning `None` if overflow occurred.
781 ///
782 /// # Examples
783 ///
784 /// ```
785 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(2), None);")]
786 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(-2), Some(3));")]
787 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_sub_signed(-4), None);")]
788 /// ```
789 #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
790 #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
791 #[must_use = "this returns the result of the operation, \
792 without modifying the original"]
793 #[inline]
794 pub const fn checked_sub_signed(self, rhs: $SignedT) -> Option<Self> {
795 let (res, overflow) = self.overflowing_sub_signed(rhs);
796
797 if !overflow {
798 Some(res)
799 } else {
800 None
801 }
802 }
803
804 /// Strict subtraction with a signed integer. Computes `self - rhs`,
805 /// panicking if overflow occurred.
806 ///
807 /// # Panics
808 ///
809 /// ## Overflow behavior
810 ///
811 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
812 ///
813 /// # Examples
814 ///
815 /// ```
816 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".strict_sub_signed(2), 1);")]
817 /// ```
818 ///
819 /// The following panic because of overflow:
820 ///
821 /// ```should_panic
822 #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_sub_signed(2);")]
823 /// ```
824 ///
825 /// ```should_panic
826 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX).strict_sub_signed(-1);")]
827 /// ```
828 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
829 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
830 #[must_use = "this returns the result of the operation, \
831 without modifying the original"]
832 #[inline]
833 #[track_caller]
834 pub const fn strict_sub_signed(self, rhs: $SignedT) -> Self {
835 let (a, b) = self.overflowing_sub_signed(rhs);
836 if b { overflow_panic::sub() } else { a }
837 }
838
839 #[doc = concat!(
840 "Checked integer subtraction. Computes `self - rhs` and checks if the result fits into an [`",
841 stringify!($SignedT), "`], returning `None` if overflow occurred."
842 )]
843 ///
844 /// # Examples
845 ///
846 /// ```
847 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_signed_diff(2), Some(8));")]
848 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_signed_diff(10), Some(-8));")]
849 #[doc = concat!(
850 "assert_eq!(",
851 stringify!($SelfT),
852 "::MAX.checked_signed_diff(",
853 stringify!($SignedT),
854 "::MAX as ",
855 stringify!($SelfT),
856 "), None);"
857 )]
858 #[doc = concat!(
859 "assert_eq!((",
860 stringify!($SignedT),
861 "::MAX as ",
862 stringify!($SelfT),
863 ").checked_signed_diff(",
864 stringify!($SelfT),
865 "::MAX), Some(",
866 stringify!($SignedT),
867 "::MIN));"
868 )]
869 #[doc = concat!(
870 "assert_eq!((",
871 stringify!($SignedT),
872 "::MAX as ",
873 stringify!($SelfT),
874 " + 1).checked_signed_diff(0), None);"
875 )]
876 #[doc = concat!(
877 "assert_eq!(",
878 stringify!($SelfT),
879 "::MAX.checked_signed_diff(",
880 stringify!($SelfT),
881 "::MAX), Some(0));"
882 )]
883 /// ```
884 #[stable(feature = "unsigned_signed_diff", since = "CURRENT_RUSTC_VERSION")]
885 #[rustc_const_stable(feature = "unsigned_signed_diff", since = "CURRENT_RUSTC_VERSION")]
886 #[inline]
887 pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> {
888 let res = self.wrapping_sub(rhs) as $SignedT;
889 let overflow = (self >= rhs) == (res < 0);
890
891 if !overflow {
892 Some(res)
893 } else {
894 None
895 }
896 }
897
898 /// Checked integer multiplication. Computes `self * rhs`, returning
899 /// `None` if overflow occurred.
900 ///
901 /// # Examples
902 ///
903 /// ```
904 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5));")]
905 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
906 /// ```
907 #[stable(feature = "rust1", since = "1.0.0")]
908 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
909 #[must_use = "this returns the result of the operation, \
910 without modifying the original"]
911 #[inline]
912 pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
913 let (a, b) = self.overflowing_mul(rhs);
914 if intrinsics::unlikely(b) { None } else { Some(a) }
915 }
916
917 /// Strict integer multiplication. Computes `self * rhs`, panicking if
918 /// overflow occurred.
919 ///
920 /// # Panics
921 ///
922 /// ## Overflow behavior
923 ///
924 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
925 ///
926 /// # Examples
927 ///
928 /// ```
929 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_mul(1), 5);")]
930 /// ```
931 ///
932 /// The following panics because of overflow:
933 ///
934 /// ``` should_panic
935 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
936 /// ```
937 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
938 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
939 #[must_use = "this returns the result of the operation, \
940 without modifying the original"]
941 #[inline]
942 #[track_caller]
943 pub const fn strict_mul(self, rhs: Self) -> Self {
944 let (a, b) = self.overflowing_mul(rhs);
945 if b { overflow_panic::mul() } else { a }
946 }
947
948 /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
949 /// cannot occur.
950 ///
951 /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
952 /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
953 ///
954 /// If you're just trying to avoid the panic in debug mode, then **do not**
955 /// use this. Instead, you're looking for [`wrapping_mul`].
956 ///
957 /// # Safety
958 ///
959 /// This results in undefined behavior when
960 #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
961 /// i.e. when [`checked_mul`] would return `None`.
962 ///
963 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
964 #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
965 #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
966 #[stable(feature = "unchecked_math", since = "1.79.0")]
967 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
968 #[must_use = "this returns the result of the operation, \
969 without modifying the original"]
970 #[inline(always)]
971 #[track_caller]
972 pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
973 assert_unsafe_precondition!(
974 check_language_ub,
975 concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
976 (
977 lhs: $SelfT = self,
978 rhs: $SelfT = rhs,
979 ) => !lhs.overflowing_mul(rhs).1,
980 );
981
982 // SAFETY: this is guaranteed to be safe by the caller.
983 unsafe {
984 intrinsics::unchecked_mul(self, rhs)
985 }
986 }
987
988 /// Checked integer division. Computes `self / rhs`, returning `None`
989 /// if `rhs == 0`.
990 ///
991 /// # Examples
992 ///
993 /// ```
994 #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")]
995 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")]
996 /// ```
997 #[stable(feature = "rust1", since = "1.0.0")]
998 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
999 #[must_use = "this returns the result of the operation, \
1000 without modifying the original"]
1001 #[inline]
1002 pub const fn checked_div(self, rhs: Self) -> Option<Self> {
1003 if intrinsics::unlikely(rhs == 0) {
1004 None
1005 } else {
1006 // SAFETY: div by zero has been checked above and unsigned types have no other
1007 // failure modes for division
1008 Some(unsafe { intrinsics::unchecked_div(self, rhs) })
1009 }
1010 }
1011
1012 /// Strict integer division. Computes `self / rhs`.
1013 ///
1014 /// Strict division on unsigned types is just normal division. There's no
1015 /// way overflow could ever happen. This function exists so that all
1016 /// operations are accounted for in the strict operations.
1017 ///
1018 /// # Panics
1019 ///
1020 /// This function will panic if `rhs` is zero.
1021 ///
1022 /// # Examples
1023 ///
1024 /// ```
1025 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div(10), 10);")]
1026 /// ```
1027 ///
1028 /// The following panics because of division by zero:
1029 ///
1030 /// ```should_panic
1031 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
1032 /// ```
1033 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1034 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1035 #[must_use = "this returns the result of the operation, \
1036 without modifying the original"]
1037 #[inline(always)]
1038 #[track_caller]
1039 pub const fn strict_div(self, rhs: Self) -> Self {
1040 self / rhs
1041 }
1042
1043 /// Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None`
1044 /// if `rhs == 0`.
1045 ///
1046 /// # Examples
1047 ///
1048 /// ```
1049 #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")]
1050 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")]
1051 /// ```
1052 #[stable(feature = "euclidean_division", since = "1.38.0")]
1053 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1054 #[must_use = "this returns the result of the operation, \
1055 without modifying the original"]
1056 #[inline]
1057 pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
1058 if intrinsics::unlikely(rhs == 0) {
1059 None
1060 } else {
1061 Some(self.div_euclid(rhs))
1062 }
1063 }
1064
1065 /// Strict Euclidean division. Computes `self.div_euclid(rhs)`.
1066 ///
1067 /// Strict division on unsigned types is just normal division. There's no
1068 /// way overflow could ever happen. This function exists so that all
1069 /// operations are accounted for in the strict operations. Since, for the
1070 /// positive integers, all common definitions of division are equal, this
1071 /// is exactly equal to `self.strict_div(rhs)`.
1072 ///
1073 /// # Panics
1074 ///
1075 /// This function will panic if `rhs` is zero.
1076 ///
1077 /// # Examples
1078 ///
1079 /// ```
1080 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div_euclid(10), 10);")]
1081 /// ```
1082 /// The following panics because of division by zero:
1083 ///
1084 /// ```should_panic
1085 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
1086 /// ```
1087 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1088 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1089 #[must_use = "this returns the result of the operation, \
1090 without modifying the original"]
1091 #[inline(always)]
1092 #[track_caller]
1093 pub const fn strict_div_euclid(self, rhs: Self) -> Self {
1094 self / rhs
1095 }
1096
1097 /// Checked integer division without remainder. Computes `self / rhs`,
1098 /// returning `None` if `rhs == 0` or if `self % rhs != 0`.
1099 ///
1100 /// # Examples
1101 ///
1102 /// ```
1103 /// #![feature(exact_div)]
1104 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_exact_div(2), Some(32));")]
1105 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_exact_div(32), Some(2));")]
1106 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_exact_div(0), None);")]
1107 #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".checked_exact_div(2), None);")]
1108 /// ```
1109 #[unstable(
1110 feature = "exact_div",
1111 issue = "139911",
1112 )]
1113 #[must_use = "this returns the result of the operation, \
1114 without modifying the original"]
1115 #[inline]
1116 pub const fn checked_exact_div(self, rhs: Self) -> Option<Self> {
1117 if intrinsics::unlikely(rhs == 0) {
1118 None
1119 } else {
1120 // SAFETY: division by zero is checked above
1121 unsafe {
1122 if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) {
1123 None
1124 } else {
1125 Some(intrinsics::exact_div(self, rhs))
1126 }
1127 }
1128 }
1129 }
1130
1131 /// Checked integer division without remainder. Computes `self / rhs`.
1132 ///
1133 /// # Panics
1134 ///
1135 /// This function will panic if `rhs == 0` or `self % rhs != 0`.
1136 ///
1137 /// # Examples
1138 ///
1139 /// ```
1140 /// #![feature(exact_div)]
1141 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".exact_div(2), 32);")]
1142 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".exact_div(32), 2);")]
1143 /// ```
1144 ///
1145 /// ```should_panic
1146 /// #![feature(exact_div)]
1147 #[doc = concat!("let _ = 65", stringify!($SelfT), ".exact_div(2);")]
1148 /// ```
1149 #[unstable(
1150 feature = "exact_div",
1151 issue = "139911",
1152 )]
1153 #[must_use = "this returns the result of the operation, \
1154 without modifying the original"]
1155 #[inline]
1156 pub const fn exact_div(self, rhs: Self) -> Self {
1157 match self.checked_exact_div(rhs) {
1158 Some(x) => x,
1159 None => panic!("Failed to divide without remainder"),
1160 }
1161 }
1162
1163 /// Unchecked integer division without remainder. Computes `self / rhs`.
1164 ///
1165 /// # Safety
1166 ///
1167 /// This results in undefined behavior when `rhs == 0` or `self % rhs != 0`,
1168 /// i.e. when [`checked_exact_div`](Self::checked_exact_div) would return `None`.
1169 #[unstable(
1170 feature = "exact_div",
1171 issue = "139911",
1172 )]
1173 #[must_use = "this returns the result of the operation, \
1174 without modifying the original"]
1175 #[inline]
1176 pub const unsafe fn unchecked_exact_div(self, rhs: Self) -> Self {
1177 assert_unsafe_precondition!(
1178 check_language_ub,
1179 concat!(stringify!($SelfT), "::unchecked_exact_div divide by zero or leave a remainder"),
1180 (
1181 lhs: $SelfT = self,
1182 rhs: $SelfT = rhs,
1183 ) => rhs > 0 && lhs % rhs == 0,
1184 );
1185 // SAFETY: Same precondition
1186 unsafe { intrinsics::exact_div(self, rhs) }
1187 }
1188
1189 /// Checked integer remainder. Computes `self % rhs`, returning `None`
1190 /// if `rhs == 0`.
1191 ///
1192 /// # Examples
1193 ///
1194 /// ```
1195 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
1196 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
1197 /// ```
1198 #[stable(feature = "wrapping", since = "1.7.0")]
1199 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1200 #[must_use = "this returns the result of the operation, \
1201 without modifying the original"]
1202 #[inline]
1203 pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
1204 if intrinsics::unlikely(rhs == 0) {
1205 None
1206 } else {
1207 // SAFETY: div by zero has been checked above and unsigned types have no other
1208 // failure modes for division
1209 Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
1210 }
1211 }
1212
1213 /// Strict integer remainder. Computes `self % rhs`.
1214 ///
1215 /// Strict remainder calculation on unsigned types is just the regular
1216 /// remainder calculation. There's no way overflow could ever happen.
1217 /// This function exists so that all operations are accounted for in the
1218 /// strict operations.
1219 ///
1220 /// # Panics
1221 ///
1222 /// This function will panic if `rhs` is zero.
1223 ///
1224 /// # Examples
1225 ///
1226 /// ```
1227 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem(10), 0);")]
1228 /// ```
1229 ///
1230 /// The following panics because of division by zero:
1231 ///
1232 /// ```should_panic
1233 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
1234 /// ```
1235 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1236 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1237 #[must_use = "this returns the result of the operation, \
1238 without modifying the original"]
1239 #[inline(always)]
1240 #[track_caller]
1241 pub const fn strict_rem(self, rhs: Self) -> Self {
1242 self % rhs
1243 }
1244
1245 /// Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None`
1246 /// if `rhs == 0`.
1247 ///
1248 /// # Examples
1249 ///
1250 /// ```
1251 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
1252 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
1253 /// ```
1254 #[stable(feature = "euclidean_division", since = "1.38.0")]
1255 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1256 #[must_use = "this returns the result of the operation, \
1257 without modifying the original"]
1258 #[inline]
1259 pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
1260 if intrinsics::unlikely(rhs == 0) {
1261 None
1262 } else {
1263 Some(self.rem_euclid(rhs))
1264 }
1265 }
1266
1267 /// Strict Euclidean modulo. Computes `self.rem_euclid(rhs)`.
1268 ///
1269 /// Strict modulo calculation on unsigned types is just the regular
1270 /// remainder calculation. There's no way overflow could ever happen.
1271 /// This function exists so that all operations are accounted for in the
1272 /// strict operations. Since, for the positive integers, all common
1273 /// definitions of division are equal, this is exactly equal to
1274 /// `self.strict_rem(rhs)`.
1275 ///
1276 /// # Panics
1277 ///
1278 /// This function will panic if `rhs` is zero.
1279 ///
1280 /// # Examples
1281 ///
1282 /// ```
1283 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem_euclid(10), 0);")]
1284 /// ```
1285 ///
1286 /// The following panics because of division by zero:
1287 ///
1288 /// ```should_panic
1289 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
1290 /// ```
1291 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1292 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1293 #[must_use = "this returns the result of the operation, \
1294 without modifying the original"]
1295 #[inline(always)]
1296 #[track_caller]
1297 pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
1298 self % rhs
1299 }
1300
1301 /// Same value as `self | other`, but UB if any bit position is set in both inputs.
1302 ///
1303 /// This is a situational micro-optimization for places where you'd rather
1304 /// use addition on some platforms and bitwise or on other platforms, based
1305 /// on exactly which instructions combine better with whatever else you're
1306 /// doing. Note that there's no reason to bother using this for places
1307 /// where it's clear from the operations involved that they can't overlap.
1308 /// For example, if you're combining `u16`s into a `u32` with
1309 /// `((a as u32) << 16) | (b as u32)`, that's fine, as the backend will
1310 /// know those sides of the `|` are disjoint without needing help.
1311 ///
1312 /// # Examples
1313 ///
1314 /// ```
1315 /// #![feature(disjoint_bitor)]
1316 ///
1317 /// // SAFETY: `1` and `4` have no bits in common.
1318 /// unsafe {
1319 #[doc = concat!(" assert_eq!(1_", stringify!($SelfT), ".unchecked_disjoint_bitor(4), 5);")]
1320 /// }
1321 /// ```
1322 ///
1323 /// # Safety
1324 ///
1325 /// Requires that `(self & other) == 0`, otherwise it's immediate UB.
1326 ///
1327 /// Equivalently, requires that `(self | other) == (self + other)`.
1328 #[unstable(feature = "disjoint_bitor", issue = "135758")]
1329 #[rustc_const_unstable(feature = "disjoint_bitor", issue = "135758")]
1330 #[inline]
1331 pub const unsafe fn unchecked_disjoint_bitor(self, other: Self) -> Self {
1332 assert_unsafe_precondition!(
1333 check_language_ub,
1334 concat!(stringify!($SelfT), "::unchecked_disjoint_bitor cannot have overlapping bits"),
1335 (
1336 lhs: $SelfT = self,
1337 rhs: $SelfT = other,
1338 ) => (lhs & rhs) == 0,
1339 );
1340
1341 // SAFETY: Same precondition
1342 unsafe { intrinsics::disjoint_bitor(self, other) }
1343 }
1344
1345 /// Returns the logarithm of the number with respect to an arbitrary base,
1346 /// rounded down.
1347 ///
1348 /// This method might not be optimized owing to implementation details;
1349 /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
1350 /// can produce results more efficiently for base 10.
1351 ///
1352 /// # Panics
1353 ///
1354 /// This function will panic if `self` is zero, or if `base` is less than 2.
1355 ///
1356 /// # Examples
1357 ///
1358 /// ```
1359 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
1360 /// ```
1361 #[stable(feature = "int_log", since = "1.67.0")]
1362 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1363 #[must_use = "this returns the result of the operation, \
1364 without modifying the original"]
1365 #[inline]
1366 #[track_caller]
1367 pub const fn ilog(self, base: Self) -> u32 {
1368 assert!(base >= 2, "base of integer logarithm must be at least 2");
1369 if let Some(log) = self.checked_ilog(base) {
1370 log
1371 } else {
1372 int_log10::panic_for_nonpositive_argument()
1373 }
1374 }
1375
1376 /// Returns the base 2 logarithm of the number, rounded down.
1377 ///
1378 /// # Panics
1379 ///
1380 /// This function will panic if `self` is zero.
1381 ///
1382 /// # Examples
1383 ///
1384 /// ```
1385 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
1386 /// ```
1387 #[stable(feature = "int_log", since = "1.67.0")]
1388 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1389 #[must_use = "this returns the result of the operation, \
1390 without modifying the original"]
1391 #[inline]
1392 #[track_caller]
1393 pub const fn ilog2(self) -> u32 {
1394 if let Some(log) = self.checked_ilog2() {
1395 log
1396 } else {
1397 int_log10::panic_for_nonpositive_argument()
1398 }
1399 }
1400
1401 /// Returns the base 10 logarithm of the number, rounded down.
1402 ///
1403 /// # Panics
1404 ///
1405 /// This function will panic if `self` is zero.
1406 ///
1407 /// # Example
1408 ///
1409 /// ```
1410 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
1411 /// ```
1412 #[stable(feature = "int_log", since = "1.67.0")]
1413 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1414 #[must_use = "this returns the result of the operation, \
1415 without modifying the original"]
1416 #[inline]
1417 #[track_caller]
1418 pub const fn ilog10(self) -> u32 {
1419 if let Some(log) = self.checked_ilog10() {
1420 log
1421 } else {
1422 int_log10::panic_for_nonpositive_argument()
1423 }
1424 }
1425
1426 /// Returns the logarithm of the number with respect to an arbitrary base,
1427 /// rounded down.
1428 ///
1429 /// Returns `None` if the number is zero, or if the base is not at least 2.
1430 ///
1431 /// This method might not be optimized owing to implementation details;
1432 /// `checked_ilog2` can produce results more efficiently for base 2, and
1433 /// `checked_ilog10` can produce results more efficiently for base 10.
1434 ///
1435 /// # Examples
1436 ///
1437 /// ```
1438 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
1439 /// ```
1440 #[stable(feature = "int_log", since = "1.67.0")]
1441 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1442 #[must_use = "this returns the result of the operation, \
1443 without modifying the original"]
1444 #[inline]
1445 pub const fn checked_ilog(self, base: Self) -> Option<u32> {
1446 if self <= 0 || base <= 1 {
1447 None
1448 } else if self < base {
1449 Some(0)
1450 } else {
1451 // Since base >= self, n >= 1
1452 let mut n = 1;
1453 let mut r = base;
1454
1455 // Optimization for 128 bit wide integers.
1456 if Self::BITS == 128 {
1457 // The following is a correct lower bound for ⌊log(base,self)⌋ because
1458 //
1459 // log(base,self) = log(2,self) / log(2,base)
1460 // ≥ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1)
1461 //
1462 // hence
1463 //
1464 // ⌊log(base,self)⌋ ≥ ⌊ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1) ⌋ .
1465 n = self.ilog2() / (base.ilog2() + 1);
1466 r = base.pow(n);
1467 }
1468
1469 while r <= self / base {
1470 n += 1;
1471 r *= base;
1472 }
1473 Some(n)
1474 }
1475 }
1476
1477 /// Returns the base 2 logarithm of the number, rounded down.
1478 ///
1479 /// Returns `None` if the number is zero.
1480 ///
1481 /// # Examples
1482 ///
1483 /// ```
1484 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
1485 /// ```
1486 #[stable(feature = "int_log", since = "1.67.0")]
1487 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1488 #[must_use = "this returns the result of the operation, \
1489 without modifying the original"]
1490 #[inline]
1491 pub const fn checked_ilog2(self) -> Option<u32> {
1492 match NonZero::new(self) {
1493 Some(x) => Some(x.ilog2()),
1494 None => None,
1495 }
1496 }
1497
1498 /// Returns the base 10 logarithm of the number, rounded down.
1499 ///
1500 /// Returns `None` if the number is zero.
1501 ///
1502 /// # Examples
1503 ///
1504 /// ```
1505 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
1506 /// ```
1507 #[stable(feature = "int_log", since = "1.67.0")]
1508 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
1509 #[must_use = "this returns the result of the operation, \
1510 without modifying the original"]
1511 #[inline]
1512 pub const fn checked_ilog10(self) -> Option<u32> {
1513 match NonZero::new(self) {
1514 Some(x) => Some(x.ilog10()),
1515 None => None,
1516 }
1517 }
1518
1519 /// Checked negation. Computes `-self`, returning `None` unless `self ==
1520 /// 0`.
1521 ///
1522 /// Note that negating any positive integer will overflow.
1523 ///
1524 /// # Examples
1525 ///
1526 /// ```
1527 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")]
1528 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")]
1529 /// ```
1530 #[stable(feature = "wrapping", since = "1.7.0")]
1531 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1532 #[must_use = "this returns the result of the operation, \
1533 without modifying the original"]
1534 #[inline]
1535 pub const fn checked_neg(self) -> Option<Self> {
1536 let (a, b) = self.overflowing_neg();
1537 if intrinsics::unlikely(b) { None } else { Some(a) }
1538 }
1539
1540 /// Strict negation. Computes `-self`, panicking unless `self ==
1541 /// 0`.
1542 ///
1543 /// Note that negating any positive integer will overflow.
1544 ///
1545 /// # Panics
1546 ///
1547 /// ## Overflow behavior
1548 ///
1549 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1550 ///
1551 /// # Examples
1552 ///
1553 /// ```
1554 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".strict_neg(), 0);")]
1555 /// ```
1556 ///
1557 /// The following panics because of overflow:
1558 ///
1559 /// ```should_panic
1560 #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_neg();")]
1561 ///
1562 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1563 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1564 #[must_use = "this returns the result of the operation, \
1565 without modifying the original"]
1566 #[inline]
1567 #[track_caller]
1568 pub const fn strict_neg(self) -> Self {
1569 let (a, b) = self.overflowing_neg();
1570 if b { overflow_panic::neg() } else { a }
1571 }
1572
1573 /// Checked shift left. Computes `self << rhs`, returning `None`
1574 /// if `rhs` is larger than or equal to the number of bits in `self`.
1575 ///
1576 /// # Examples
1577 ///
1578 /// ```
1579 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
1580 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")]
1581 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
1582 /// ```
1583 #[stable(feature = "wrapping", since = "1.7.0")]
1584 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1585 #[must_use = "this returns the result of the operation, \
1586 without modifying the original"]
1587 #[inline]
1588 pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
1589 // Not using overflowing_shl as that's a wrapping shift
1590 if rhs < Self::BITS {
1591 // SAFETY: just checked the RHS is in-range
1592 Some(unsafe { self.unchecked_shl(rhs) })
1593 } else {
1594 None
1595 }
1596 }
1597
1598 /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
1599 /// than or equal to the number of bits in `self`.
1600 ///
1601 /// # Panics
1602 ///
1603 /// ## Overflow behavior
1604 ///
1605 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1606 ///
1607 /// # Examples
1608 ///
1609 /// ```
1610 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
1611 /// ```
1612 ///
1613 /// The following panics because of overflow:
1614 ///
1615 /// ```should_panic
1616 #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shl(129);")]
1617 /// ```
1618 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1619 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1620 #[must_use = "this returns the result of the operation, \
1621 without modifying the original"]
1622 #[inline]
1623 #[track_caller]
1624 pub const fn strict_shl(self, rhs: u32) -> Self {
1625 let (a, b) = self.overflowing_shl(rhs);
1626 if b { overflow_panic::shl() } else { a }
1627 }
1628
1629 /// Unchecked shift left. Computes `self << rhs`, assuming that
1630 /// `rhs` is less than the number of bits in `self`.
1631 ///
1632 /// # Safety
1633 ///
1634 /// This results in undefined behavior if `rhs` is larger than
1635 /// or equal to the number of bits in `self`,
1636 /// i.e. when [`checked_shl`] would return `None`.
1637 ///
1638 #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
1639 #[unstable(
1640 feature = "unchecked_shifts",
1641 reason = "niche optimization path",
1642 issue = "85122",
1643 )]
1644 #[must_use = "this returns the result of the operation, \
1645 without modifying the original"]
1646 #[inline(always)]
1647 #[track_caller]
1648 pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
1649 assert_unsafe_precondition!(
1650 check_language_ub,
1651 concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
1652 (
1653 rhs: u32 = rhs,
1654 ) => rhs < <$ActualT>::BITS,
1655 );
1656
1657 // SAFETY: this is guaranteed to be safe by the caller.
1658 unsafe {
1659 intrinsics::unchecked_shl(self, rhs)
1660 }
1661 }
1662
1663 /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`.
1664 ///
1665 /// If `rhs` is larger or equal to the number of bits in `self`,
1666 /// the entire value is shifted out, and `0` is returned.
1667 ///
1668 /// # Examples
1669 ///
1670 /// ```
1671 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
1672 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(129), 0);")]
1673 /// ```
1674 #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1675 #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1676 #[must_use = "this returns the result of the operation, \
1677 without modifying the original"]
1678 #[inline]
1679 pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
1680 if rhs < Self::BITS {
1681 // SAFETY:
1682 // rhs is just checked to be in-range above
1683 unsafe { self.unchecked_shl(rhs) }
1684 } else {
1685 0
1686 }
1687 }
1688
1689 /// Checked shift right. Computes `self >> rhs`, returning `None`
1690 /// if `rhs` is larger than or equal to the number of bits in `self`.
1691 ///
1692 /// # Examples
1693 ///
1694 /// ```
1695 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
1696 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);")]
1697 /// ```
1698 #[stable(feature = "wrapping", since = "1.7.0")]
1699 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1700 #[must_use = "this returns the result of the operation, \
1701 without modifying the original"]
1702 #[inline]
1703 pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
1704 // Not using overflowing_shr as that's a wrapping shift
1705 if rhs < Self::BITS {
1706 // SAFETY: just checked the RHS is in-range
1707 Some(unsafe { self.unchecked_shr(rhs) })
1708 } else {
1709 None
1710 }
1711 }
1712
1713 /// Strict shift right. Computes `self >> rhs`, panicking `rhs` is
1714 /// larger than or equal to the number of bits in `self`.
1715 ///
1716 /// # Panics
1717 ///
1718 /// ## Overflow behavior
1719 ///
1720 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1721 ///
1722 /// # Examples
1723 ///
1724 /// ```
1725 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
1726 /// ```
1727 ///
1728 /// The following panics because of overflow:
1729 ///
1730 /// ```should_panic
1731 #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(129);")]
1732 /// ```
1733 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1734 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1735 #[must_use = "this returns the result of the operation, \
1736 without modifying the original"]
1737 #[inline]
1738 #[track_caller]
1739 pub const fn strict_shr(self, rhs: u32) -> Self {
1740 let (a, b) = self.overflowing_shr(rhs);
1741 if b { overflow_panic::shr() } else { a }
1742 }
1743
1744 /// Unchecked shift right. Computes `self >> rhs`, assuming that
1745 /// `rhs` is less than the number of bits in `self`.
1746 ///
1747 /// # Safety
1748 ///
1749 /// This results in undefined behavior if `rhs` is larger than
1750 /// or equal to the number of bits in `self`,
1751 /// i.e. when [`checked_shr`] would return `None`.
1752 ///
1753 #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
1754 #[unstable(
1755 feature = "unchecked_shifts",
1756 reason = "niche optimization path",
1757 issue = "85122",
1758 )]
1759 #[must_use = "this returns the result of the operation, \
1760 without modifying the original"]
1761 #[inline(always)]
1762 #[track_caller]
1763 pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
1764 assert_unsafe_precondition!(
1765 check_language_ub,
1766 concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
1767 (
1768 rhs: u32 = rhs,
1769 ) => rhs < <$ActualT>::BITS,
1770 );
1771
1772 // SAFETY: this is guaranteed to be safe by the caller.
1773 unsafe {
1774 intrinsics::unchecked_shr(self, rhs)
1775 }
1776 }
1777
1778 /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`.
1779 ///
1780 /// If `rhs` is larger or equal to the number of bits in `self`,
1781 /// the entire value is shifted out, and `0` is returned.
1782 ///
1783 /// # Examples
1784 ///
1785 /// ```
1786 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
1787 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(129), 0);")]
1788 /// ```
1789 #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1790 #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1791 #[must_use = "this returns the result of the operation, \
1792 without modifying the original"]
1793 #[inline]
1794 pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
1795 if rhs < Self::BITS {
1796 // SAFETY:
1797 // rhs is just checked to be in-range above
1798 unsafe { self.unchecked_shr(rhs) }
1799 } else {
1800 0
1801 }
1802 }
1803
1804 /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
1805 /// overflow occurred.
1806 ///
1807 /// # Examples
1808 ///
1809 /// ```
1810 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")]
1811 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
1812 /// ```
1813 #[stable(feature = "no_panic_pow", since = "1.34.0")]
1814 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
1815 #[must_use = "this returns the result of the operation, \
1816 without modifying the original"]
1817 #[inline]
1818 pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
1819 if exp == 0 {
1820 return Some(1);
1821 }
1822 let mut base = self;
1823 let mut acc: Self = 1;
1824
1825 loop {
1826 if (exp & 1) == 1 {
1827 acc = try_opt!(acc.checked_mul(base));
1828 // since exp!=0, finally the exp must be 1.
1829 if exp == 1 {
1830 return Some(acc);
1831 }
1832 }
1833 exp /= 2;
1834 base = try_opt!(base.checked_mul(base));
1835 }
1836 }
1837
1838 /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
1839 /// overflow occurred.
1840 ///
1841 /// # Panics
1842 ///
1843 /// ## Overflow behavior
1844 ///
1845 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1846 ///
1847 /// # Examples
1848 ///
1849 /// ```
1850 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".strict_pow(5), 32);")]
1851 /// ```
1852 ///
1853 /// The following panics because of overflow:
1854 ///
1855 /// ```should_panic
1856 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
1857 /// ```
1858 #[stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1859 #[rustc_const_stable(feature = "strict_overflow_ops", since = "CURRENT_RUSTC_VERSION")]
1860 #[must_use = "this returns the result of the operation, \
1861 without modifying the original"]
1862 #[inline]
1863 #[track_caller]
1864 pub const fn strict_pow(self, mut exp: u32) -> Self {
1865 if exp == 0 {
1866 return 1;
1867 }
1868 let mut base = self;
1869 let mut acc: Self = 1;
1870
1871 loop {
1872 if (exp & 1) == 1 {
1873 acc = acc.strict_mul(base);
1874 // since exp!=0, finally the exp must be 1.
1875 if exp == 1 {
1876 return acc;
1877 }
1878 }
1879 exp /= 2;
1880 base = base.strict_mul(base);
1881 }
1882 }
1883
1884 /// Saturating integer addition. Computes `self + rhs`, saturating at
1885 /// the numeric bounds instead of overflowing.
1886 ///
1887 /// # Examples
1888 ///
1889 /// ```
1890 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
1891 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);")]
1892 /// ```
1893 #[stable(feature = "rust1", since = "1.0.0")]
1894 #[must_use = "this returns the result of the operation, \
1895 without modifying the original"]
1896 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1897 #[inline(always)]
1898 pub const fn saturating_add(self, rhs: Self) -> Self {
1899 intrinsics::saturating_add(self, rhs)
1900 }
1901
1902 /// Saturating addition with a signed integer. Computes `self + rhs`,
1903 /// saturating at the numeric bounds instead of overflowing.
1904 ///
1905 /// # Examples
1906 ///
1907 /// ```
1908 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")]
1909 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")]
1910 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")]
1911 /// ```
1912 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1913 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1914 #[must_use = "this returns the result of the operation, \
1915 without modifying the original"]
1916 #[inline]
1917 pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self {
1918 let (res, overflow) = self.overflowing_add(rhs as Self);
1919 if overflow == (rhs < 0) {
1920 res
1921 } else if overflow {
1922 Self::MAX
1923 } else {
1924 0
1925 }
1926 }
1927
1928 /// Saturating integer subtraction. Computes `self - rhs`, saturating
1929 /// at the numeric bounds instead of overflowing.
1930 ///
1931 /// # Examples
1932 ///
1933 /// ```
1934 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")]
1935 #[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")]
1936 /// ```
1937 #[stable(feature = "rust1", since = "1.0.0")]
1938 #[must_use = "this returns the result of the operation, \
1939 without modifying the original"]
1940 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1941 #[inline(always)]
1942 pub const fn saturating_sub(self, rhs: Self) -> Self {
1943 intrinsics::saturating_sub(self, rhs)
1944 }
1945
1946 /// Saturating integer subtraction. Computes `self` - `rhs`, saturating at
1947 /// the numeric bounds instead of overflowing.
1948 ///
1949 /// # Examples
1950 ///
1951 /// ```
1952 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(2), 0);")]
1953 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(-2), 3);")]
1954 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_sub_signed(-4), ", stringify!($SelfT), "::MAX);")]
1955 /// ```
1956 #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
1957 #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
1958 #[must_use = "this returns the result of the operation, \
1959 without modifying the original"]
1960 #[inline]
1961 pub const fn saturating_sub_signed(self, rhs: $SignedT) -> Self {
1962 let (res, overflow) = self.overflowing_sub_signed(rhs);
1963
1964 if !overflow {
1965 res
1966 } else if rhs < 0 {
1967 Self::MAX
1968 } else {
1969 0
1970 }
1971 }
1972
1973 /// Saturating integer multiplication. Computes `self * rhs`,
1974 /// saturating at the numeric bounds instead of overflowing.
1975 ///
1976 /// # Examples
1977 ///
1978 /// ```
1979 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20);")]
1980 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT),"::MAX);")]
1981 /// ```
1982 #[stable(feature = "wrapping", since = "1.7.0")]
1983 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1984 #[must_use = "this returns the result of the operation, \
1985 without modifying the original"]
1986 #[inline]
1987 pub const fn saturating_mul(self, rhs: Self) -> Self {
1988 match self.checked_mul(rhs) {
1989 Some(x) => x,
1990 None => Self::MAX,
1991 }
1992 }
1993
1994 /// Saturating integer division. Computes `self / rhs`, saturating at the
1995 /// numeric bounds instead of overflowing.
1996 ///
1997 /// # Panics
1998 ///
1999 /// This function will panic if `rhs` is zero.
2000 ///
2001 /// # Examples
2002 ///
2003 /// ```
2004 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
2005 ///
2006 /// ```
2007 #[stable(feature = "saturating_div", since = "1.58.0")]
2008 #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
2009 #[must_use = "this returns the result of the operation, \
2010 without modifying the original"]
2011 #[inline]
2012 #[track_caller]
2013 pub const fn saturating_div(self, rhs: Self) -> Self {
2014 // on unsigned types, there is no overflow in integer division
2015 self.wrapping_div(rhs)
2016 }
2017
2018 /// Saturating integer exponentiation. Computes `self.pow(exp)`,
2019 /// saturating at the numeric bounds instead of overflowing.
2020 ///
2021 /// # Examples
2022 ///
2023 /// ```
2024 #[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")]
2025 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
2026 /// ```
2027 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2028 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2029 #[must_use = "this returns the result of the operation, \
2030 without modifying the original"]
2031 #[inline]
2032 pub const fn saturating_pow(self, exp: u32) -> Self {
2033 match self.checked_pow(exp) {
2034 Some(x) => x,
2035 None => Self::MAX,
2036 }
2037 }
2038
2039 /// Wrapping (modular) addition. Computes `self + rhs`,
2040 /// wrapping around at the boundary of the type.
2041 ///
2042 /// # Examples
2043 ///
2044 /// ```
2045 #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255);")]
2046 #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);")]
2047 /// ```
2048 #[stable(feature = "rust1", since = "1.0.0")]
2049 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2050 #[must_use = "this returns the result of the operation, \
2051 without modifying the original"]
2052 #[inline(always)]
2053 pub const fn wrapping_add(self, rhs: Self) -> Self {
2054 intrinsics::wrapping_add(self, rhs)
2055 }
2056
2057 /// Wrapping (modular) addition with a signed integer. Computes
2058 /// `self + rhs`, wrapping around at the boundary of the type.
2059 ///
2060 /// # Examples
2061 ///
2062 /// ```
2063 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")]
2064 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")]
2065 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")]
2066 /// ```
2067 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2068 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2069 #[must_use = "this returns the result of the operation, \
2070 without modifying the original"]
2071 #[inline]
2072 pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self {
2073 self.wrapping_add(rhs as Self)
2074 }
2075
2076 /// Wrapping (modular) subtraction. Computes `self - rhs`,
2077 /// wrapping around at the boundary of the type.
2078 ///
2079 /// # Examples
2080 ///
2081 /// ```
2082 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0);")]
2083 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);")]
2084 /// ```
2085 #[stable(feature = "rust1", since = "1.0.0")]
2086 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2087 #[must_use = "this returns the result of the operation, \
2088 without modifying the original"]
2089 #[inline(always)]
2090 pub const fn wrapping_sub(self, rhs: Self) -> Self {
2091 intrinsics::wrapping_sub(self, rhs)
2092 }
2093
2094 /// Wrapping (modular) subtraction with a signed integer. Computes
2095 /// `self - rhs`, wrapping around at the boundary of the type.
2096 ///
2097 /// # Examples
2098 ///
2099 /// ```
2100 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(2), ", stringify!($SelfT), "::MAX);")]
2101 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(-2), 3);")]
2102 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_sub_signed(-4), 1);")]
2103 /// ```
2104 #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2105 #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2106 #[must_use = "this returns the result of the operation, \
2107 without modifying the original"]
2108 #[inline]
2109 pub const fn wrapping_sub_signed(self, rhs: $SignedT) -> Self {
2110 self.wrapping_sub(rhs as Self)
2111 }
2112
2113 /// Wrapping (modular) multiplication. Computes `self *
2114 /// rhs`, wrapping around at the boundary of the type.
2115 ///
2116 /// # Examples
2117 ///
2118 /// Please note that this example is shared between integer types.
2119 /// Which explains why `u8` is used here.
2120 ///
2121 /// ```
2122 /// assert_eq!(10u8.wrapping_mul(12), 120);
2123 /// assert_eq!(25u8.wrapping_mul(12), 44);
2124 /// ```
2125 #[stable(feature = "rust1", since = "1.0.0")]
2126 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2127 #[must_use = "this returns the result of the operation, \
2128 without modifying the original"]
2129 #[inline(always)]
2130 pub const fn wrapping_mul(self, rhs: Self) -> Self {
2131 intrinsics::wrapping_mul(self, rhs)
2132 }
2133
2134 /// Wrapping (modular) division. Computes `self / rhs`.
2135 ///
2136 /// Wrapped division on unsigned types is just normal division. There's
2137 /// no way wrapping could ever happen. This function exists so that all
2138 /// operations are accounted for in the wrapping operations.
2139 ///
2140 /// # Panics
2141 ///
2142 /// This function will panic if `rhs` is zero.
2143 ///
2144 /// # Examples
2145 ///
2146 /// ```
2147 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
2148 /// ```
2149 #[stable(feature = "num_wrapping", since = "1.2.0")]
2150 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2151 #[must_use = "this returns the result of the operation, \
2152 without modifying the original"]
2153 #[inline(always)]
2154 #[track_caller]
2155 pub const fn wrapping_div(self, rhs: Self) -> Self {
2156 self / rhs
2157 }
2158
2159 /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`.
2160 ///
2161 /// Wrapped division on unsigned types is just normal division. There's
2162 /// no way wrapping could ever happen. This function exists so that all
2163 /// operations are accounted for in the wrapping operations. Since, for
2164 /// the positive integers, all common definitions of division are equal,
2165 /// this is exactly equal to `self.wrapping_div(rhs)`.
2166 ///
2167 /// # Panics
2168 ///
2169 /// This function will panic if `rhs` is zero.
2170 ///
2171 /// # Examples
2172 ///
2173 /// ```
2174 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
2175 /// ```
2176 #[stable(feature = "euclidean_division", since = "1.38.0")]
2177 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2178 #[must_use = "this returns the result of the operation, \
2179 without modifying the original"]
2180 #[inline(always)]
2181 #[track_caller]
2182 pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
2183 self / rhs
2184 }
2185
2186 /// Wrapping (modular) remainder. Computes `self % rhs`.
2187 ///
2188 /// Wrapped remainder calculation on unsigned types is just the regular
2189 /// remainder calculation. There's no way wrapping could ever happen.
2190 /// This function exists so that all operations are accounted for in the
2191 /// wrapping operations.
2192 ///
2193 /// # Panics
2194 ///
2195 /// This function will panic if `rhs` is zero.
2196 ///
2197 /// # Examples
2198 ///
2199 /// ```
2200 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
2201 /// ```
2202 #[stable(feature = "num_wrapping", since = "1.2.0")]
2203 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2204 #[must_use = "this returns the result of the operation, \
2205 without modifying the original"]
2206 #[inline(always)]
2207 #[track_caller]
2208 pub const fn wrapping_rem(self, rhs: Self) -> Self {
2209 self % rhs
2210 }
2211
2212 /// Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`.
2213 ///
2214 /// Wrapped modulo calculation on unsigned types is just the regular
2215 /// remainder calculation. There's no way wrapping could ever happen.
2216 /// This function exists so that all operations are accounted for in the
2217 /// wrapping operations. Since, for the positive integers, all common
2218 /// definitions of division are equal, this is exactly equal to
2219 /// `self.wrapping_rem(rhs)`.
2220 ///
2221 /// # Panics
2222 ///
2223 /// This function will panic if `rhs` is zero.
2224 ///
2225 /// # Examples
2226 ///
2227 /// ```
2228 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
2229 /// ```
2230 #[stable(feature = "euclidean_division", since = "1.38.0")]
2231 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2232 #[must_use = "this returns the result of the operation, \
2233 without modifying the original"]
2234 #[inline(always)]
2235 #[track_caller]
2236 pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
2237 self % rhs
2238 }
2239
2240 /// Wrapping (modular) negation. Computes `-self`,
2241 /// wrapping around at the boundary of the type.
2242 ///
2243 /// Since unsigned types do not have negative equivalents
2244 /// all applications of this function will wrap (except for `-0`).
2245 /// For values smaller than the corresponding signed type's maximum
2246 /// the result is the same as casting the corresponding signed value.
2247 /// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where
2248 /// `MAX` is the corresponding signed type's maximum.
2249 ///
2250 /// # Examples
2251 ///
2252 /// ```
2253 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_neg(), 0);")]
2254 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_neg(), 1);")]
2255 #[doc = concat!("assert_eq!(13_", stringify!($SelfT), ".wrapping_neg(), (!13) + 1);")]
2256 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_neg(), !(42 - 1));")]
2257 /// ```
2258 #[stable(feature = "num_wrapping", since = "1.2.0")]
2259 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2260 #[must_use = "this returns the result of the operation, \
2261 without modifying the original"]
2262 #[inline(always)]
2263 pub const fn wrapping_neg(self) -> Self {
2264 (0 as $SelfT).wrapping_sub(self)
2265 }
2266
2267 /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
2268 /// where `mask` removes any high-order bits of `rhs` that
2269 /// would cause the shift to exceed the bitwidth of the type.
2270 ///
2271 /// Note that this is *not* the same as a rotate-left; the
2272 /// RHS of a wrapping shift-left is restricted to the range
2273 /// of the type, rather than the bits shifted out of the LHS
2274 /// being returned to the other end. The primitive integer
2275 /// types all implement a [`rotate_left`](Self::rotate_left) function,
2276 /// which may be what you want instead.
2277 ///
2278 /// # Examples
2279 ///
2280 /// ```
2281 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(7), 128);")]
2282 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(128), 1);")]
2283 /// ```
2284 #[stable(feature = "num_wrapping", since = "1.2.0")]
2285 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2286 #[must_use = "this returns the result of the operation, \
2287 without modifying the original"]
2288 #[inline(always)]
2289 pub const fn wrapping_shl(self, rhs: u32) -> Self {
2290 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2291 // out of bounds
2292 unsafe {
2293 self.unchecked_shl(rhs & (Self::BITS - 1))
2294 }
2295 }
2296
2297 /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
2298 /// where `mask` removes any high-order bits of `rhs` that
2299 /// would cause the shift to exceed the bitwidth of the type.
2300 ///
2301 /// Note that this is *not* the same as a rotate-right; the
2302 /// RHS of a wrapping shift-right is restricted to the range
2303 /// of the type, rather than the bits shifted out of the LHS
2304 /// being returned to the other end. The primitive integer
2305 /// types all implement a [`rotate_right`](Self::rotate_right) function,
2306 /// which may be what you want instead.
2307 ///
2308 /// # Examples
2309 ///
2310 /// ```
2311 #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(7), 1);")]
2312 #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(128), 128);")]
2313 /// ```
2314 #[stable(feature = "num_wrapping", since = "1.2.0")]
2315 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2316 #[must_use = "this returns the result of the operation, \
2317 without modifying the original"]
2318 #[inline(always)]
2319 pub const fn wrapping_shr(self, rhs: u32) -> Self {
2320 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2321 // out of bounds
2322 unsafe {
2323 self.unchecked_shr(rhs & (Self::BITS - 1))
2324 }
2325 }
2326
2327 /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
2328 /// wrapping around at the boundary of the type.
2329 ///
2330 /// # Examples
2331 ///
2332 /// ```
2333 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")]
2334 /// assert_eq!(3u8.wrapping_pow(6), 217);
2335 /// ```
2336 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2337 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2338 #[must_use = "this returns the result of the operation, \
2339 without modifying the original"]
2340 #[inline]
2341 pub const fn wrapping_pow(self, mut exp: u32) -> Self {
2342 if exp == 0 {
2343 return 1;
2344 }
2345 let mut base = self;
2346 let mut acc: Self = 1;
2347
2348 if intrinsics::is_val_statically_known(exp) {
2349 while exp > 1 {
2350 if (exp & 1) == 1 {
2351 acc = acc.wrapping_mul(base);
2352 }
2353 exp /= 2;
2354 base = base.wrapping_mul(base);
2355 }
2356
2357 // since exp!=0, finally the exp must be 1.
2358 // Deal with the final bit of the exponent separately, since
2359 // squaring the base afterwards is not necessary.
2360 acc.wrapping_mul(base)
2361 } else {
2362 // This is faster than the above when the exponent is not known
2363 // at compile time. We can't use the same code for the constant
2364 // exponent case because LLVM is currently unable to unroll
2365 // this loop.
2366 loop {
2367 if (exp & 1) == 1 {
2368 acc = acc.wrapping_mul(base);
2369 // since exp!=0, finally the exp must be 1.
2370 if exp == 1 {
2371 return acc;
2372 }
2373 }
2374 exp /= 2;
2375 base = base.wrapping_mul(base);
2376 }
2377 }
2378 }
2379
2380 /// Calculates `self` + `rhs`.
2381 ///
2382 /// Returns a tuple of the addition along with a boolean indicating
2383 /// whether an arithmetic overflow would occur. If an overflow would
2384 /// have occurred then the wrapped value is returned.
2385 ///
2386 /// # Examples
2387 ///
2388 /// ```
2389 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
2390 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));")]
2391 /// ```
2392 #[stable(feature = "wrapping", since = "1.7.0")]
2393 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2394 #[must_use = "this returns the result of the operation, \
2395 without modifying the original"]
2396 #[inline(always)]
2397 pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
2398 let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
2399 (a as Self, b)
2400 }
2401
2402 /// Calculates `self` + `rhs` + `carry` and returns a tuple containing
2403 /// the sum and the output carry.
2404 ///
2405 /// Performs "ternary addition" of two integer operands and a carry-in
2406 /// bit, and returns an output integer and a carry-out bit. This allows
2407 /// chaining together multiple additions to create a wider addition, and
2408 /// can be useful for bignum addition.
2409 ///
2410 #[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit \"full adder\", in the electronics sense.")]
2411 ///
2412 /// If the input carry is false, this method is equivalent to
2413 /// [`overflowing_add`](Self::overflowing_add), and the output carry is
2414 /// equal to the overflow flag. Note that although carry and overflow
2415 /// flags are similar for unsigned integers, they are different for
2416 /// signed integers.
2417 ///
2418 /// # Examples
2419 ///
2420 /// ```
2421 /// #![feature(bigint_helper_methods)]
2422 ///
2423 #[doc = concat!("// 3 MAX (a = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2424 #[doc = concat!("// + 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")]
2425 /// // ---------
2426 #[doc = concat!("// 9 6 (sum = 9 × 2^", stringify!($BITS), " + 6)")]
2427 ///
2428 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (3, ", stringify!($SelfT), "::MAX);")]
2429 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
2430 /// let carry0 = false;
2431 ///
2432 /// let (sum0, carry1) = a0.carrying_add(b0, carry0);
2433 /// assert_eq!(carry1, true);
2434 /// let (sum1, carry2) = a1.carrying_add(b1, carry1);
2435 /// assert_eq!(carry2, false);
2436 ///
2437 /// assert_eq!((sum1, sum0), (9, 6));
2438 /// ```
2439 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2440 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2441 #[must_use = "this returns the result of the operation, \
2442 without modifying the original"]
2443 #[inline]
2444 pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
2445 // note: longer-term this should be done via an intrinsic, but this has been shown
2446 // to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
2447 let (a, c1) = self.overflowing_add(rhs);
2448 let (b, c2) = a.overflowing_add(carry as $SelfT);
2449 // Ideally LLVM would know this is disjoint without us telling them,
2450 // but it doesn't <https://github.com/llvm/llvm-project/issues/118162>
2451 // SAFETY: Only one of `c1` and `c2` can be set.
2452 // For c1 to be set we need to have overflowed, but if we did then
2453 // `a` is at most `MAX-1`, which means that `c2` cannot possibly
2454 // overflow because it's adding at most `1` (since it came from `bool`)
2455 (b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
2456 }
2457
2458 /// Calculates `self` + `rhs` with a signed `rhs`.
2459 ///
2460 /// Returns a tuple of the addition along with a boolean indicating
2461 /// whether an arithmetic overflow would occur. If an overflow would
2462 /// have occurred then the wrapped value is returned.
2463 ///
2464 /// # Examples
2465 ///
2466 /// ```
2467 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")]
2468 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")]
2469 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")]
2470 /// ```
2471 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2472 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2473 #[must_use = "this returns the result of the operation, \
2474 without modifying the original"]
2475 #[inline]
2476 pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) {
2477 let (res, overflowed) = self.overflowing_add(rhs as Self);
2478 (res, overflowed ^ (rhs < 0))
2479 }
2480
2481 /// Calculates `self` - `rhs`.
2482 ///
2483 /// Returns a tuple of the subtraction along with a boolean indicating
2484 /// whether an arithmetic overflow would occur. If an overflow would
2485 /// have occurred then the wrapped value is returned.
2486 ///
2487 /// # Examples
2488 ///
2489 /// ```
2490 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
2491 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
2492 /// ```
2493 #[stable(feature = "wrapping", since = "1.7.0")]
2494 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2495 #[must_use = "this returns the result of the operation, \
2496 without modifying the original"]
2497 #[inline(always)]
2498 pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
2499 let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
2500 (a as Self, b)
2501 }
2502
2503 /// Calculates `self` − `rhs` − `borrow` and returns a tuple
2504 /// containing the difference and the output borrow.
2505 ///
2506 /// Performs "ternary subtraction" by subtracting both an integer
2507 /// operand and a borrow-in bit from `self`, and returns an output
2508 /// integer and a borrow-out bit. This allows chaining together multiple
2509 /// subtractions to create a wider subtraction, and can be useful for
2510 /// bignum subtraction.
2511 ///
2512 /// # Examples
2513 ///
2514 /// ```
2515 /// #![feature(bigint_helper_methods)]
2516 ///
2517 #[doc = concat!("// 9 6 (a = 9 × 2^", stringify!($BITS), " + 6)")]
2518 #[doc = concat!("// - 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")]
2519 /// // ---------
2520 #[doc = concat!("// 3 MAX (diff = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2521 ///
2522 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (9, 6);")]
2523 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")]
2524 /// let borrow0 = false;
2525 ///
2526 /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
2527 /// assert_eq!(borrow1, true);
2528 /// let (diff1, borrow2) = a1.borrowing_sub(b1, borrow1);
2529 /// assert_eq!(borrow2, false);
2530 ///
2531 #[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")]
2532 /// ```
2533 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2534 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2535 #[must_use = "this returns the result of the operation, \
2536 without modifying the original"]
2537 #[inline]
2538 pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
2539 // note: longer-term this should be done via an intrinsic, but this has been shown
2540 // to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic
2541 let (a, c1) = self.overflowing_sub(rhs);
2542 let (b, c2) = a.overflowing_sub(borrow as $SelfT);
2543 // SAFETY: Only one of `c1` and `c2` can be set.
2544 // For c1 to be set we need to have underflowed, but if we did then
2545 // `a` is nonzero, which means that `c2` cannot possibly
2546 // underflow because it's subtracting at most `1` (since it came from `bool`)
2547 (b, unsafe { intrinsics::disjoint_bitor(c1, c2) })
2548 }
2549
2550 /// Calculates `self` - `rhs` with a signed `rhs`
2551 ///
2552 /// Returns a tuple of the subtraction along with a boolean indicating
2553 /// whether an arithmetic overflow would occur. If an overflow would
2554 /// have occurred then the wrapped value is returned.
2555 ///
2556 /// # Examples
2557 ///
2558 /// ```
2559 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(2), (", stringify!($SelfT), "::MAX, true));")]
2560 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(-2), (3, false));")]
2561 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_sub_signed(-4), (1, true));")]
2562 /// ```
2563 #[stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2564 #[rustc_const_stable(feature = "mixed_integer_ops_unsigned_sub", since = "1.90.0")]
2565 #[must_use = "this returns the result of the operation, \
2566 without modifying the original"]
2567 #[inline]
2568 pub const fn overflowing_sub_signed(self, rhs: $SignedT) -> (Self, bool) {
2569 let (res, overflow) = self.overflowing_sub(rhs as Self);
2570
2571 (res, overflow ^ (rhs < 0))
2572 }
2573
2574 /// Computes the absolute difference between `self` and `other`.
2575 ///
2576 /// # Examples
2577 ///
2578 /// ```
2579 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($SelfT), ");")]
2580 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($SelfT), ");")]
2581 /// ```
2582 #[stable(feature = "int_abs_diff", since = "1.60.0")]
2583 #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
2584 #[must_use = "this returns the result of the operation, \
2585 without modifying the original"]
2586 #[inline]
2587 pub const fn abs_diff(self, other: Self) -> Self {
2588 if size_of::<Self>() == 1 {
2589 // Trick LLVM into generating the psadbw instruction when SSE2
2590 // is available and this function is autovectorized for u8's.
2591 (self as i32).wrapping_sub(other as i32).unsigned_abs() as Self
2592 } else {
2593 if self < other {
2594 other - self
2595 } else {
2596 self - other
2597 }
2598 }
2599 }
2600
2601 /// Calculates the multiplication of `self` and `rhs`.
2602 ///
2603 /// Returns a tuple of the multiplication along with a boolean
2604 /// indicating whether an arithmetic overflow would occur. If an
2605 /// overflow would have occurred then the wrapped value is returned.
2606 ///
2607 /// # Examples
2608 ///
2609 /// Please note that this example is shared between integer types.
2610 /// Which explains why `u32` is used here.
2611 ///
2612 /// ```
2613 /// assert_eq!(5u32.overflowing_mul(2), (10, false));
2614 /// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
2615 /// ```
2616 #[stable(feature = "wrapping", since = "1.7.0")]
2617 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2618 #[must_use = "this returns the result of the operation, \
2619 without modifying the original"]
2620 #[inline(always)]
2621 pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
2622 let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
2623 (a as Self, b)
2624 }
2625
2626 /// Calculates the complete product `self * rhs` without the possibility to overflow.
2627 ///
2628 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2629 /// of the result as two separate values, in that order.
2630 ///
2631 /// If you also need to add a carry to the wide result, then you want
2632 /// [`Self::carrying_mul`] instead.
2633 ///
2634 /// # Examples
2635 ///
2636 /// Please note that this example is shared between integer types.
2637 /// Which explains why `u32` is used here.
2638 ///
2639 /// ```
2640 /// #![feature(bigint_helper_methods)]
2641 /// assert_eq!(5u32.widening_mul(2), (10, 0));
2642 /// assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2));
2643 /// ```
2644 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2645 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2646 #[must_use = "this returns the result of the operation, \
2647 without modifying the original"]
2648 #[inline]
2649 pub const fn widening_mul(self, rhs: Self) -> (Self, Self) {
2650 Self::carrying_mul_add(self, rhs, 0, 0)
2651 }
2652
2653 /// Calculates the "full multiplication" `self * rhs + carry`
2654 /// without the possibility to overflow.
2655 ///
2656 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2657 /// of the result as two separate values, in that order.
2658 ///
2659 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2660 /// additional amount of overflow. This allows for chaining together multiple
2661 /// multiplications to create "big integers" which represent larger values.
2662 ///
2663 /// If you don't need the `carry`, then you can use [`Self::widening_mul`] instead.
2664 ///
2665 /// # Examples
2666 ///
2667 /// Please note that this example is shared between integer types.
2668 /// Which explains why `u32` is used here.
2669 ///
2670 /// ```
2671 /// #![feature(bigint_helper_methods)]
2672 /// assert_eq!(5u32.carrying_mul(2, 0), (10, 0));
2673 /// assert_eq!(5u32.carrying_mul(2, 10), (20, 0));
2674 /// assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2));
2675 /// assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2));
2676 #[doc = concat!("assert_eq!(",
2677 stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2678 "(0, ", stringify!($SelfT), "::MAX));"
2679 )]
2680 /// ```
2681 ///
2682 /// This is the core operation needed for scalar multiplication when
2683 /// implementing it for wider-than-native types.
2684 ///
2685 /// ```
2686 /// #![feature(bigint_helper_methods)]
2687 /// fn scalar_mul_eq(little_endian_digits: &mut Vec<u16>, multiplicand: u16) {
2688 /// let mut carry = 0;
2689 /// for d in little_endian_digits.iter_mut() {
2690 /// (*d, carry) = d.carrying_mul(multiplicand, carry);
2691 /// }
2692 /// if carry != 0 {
2693 /// little_endian_digits.push(carry);
2694 /// }
2695 /// }
2696 ///
2697 /// let mut v = vec![10, 20];
2698 /// scalar_mul_eq(&mut v, 3);
2699 /// assert_eq!(v, [30, 60]);
2700 ///
2701 /// assert_eq!(0x87654321_u64 * 0xFEED, 0x86D3D159E38D);
2702 /// let mut v = vec![0x4321, 0x8765];
2703 /// scalar_mul_eq(&mut v, 0xFEED);
2704 /// assert_eq!(v, [0xE38D, 0xD159, 0x86D3]);
2705 /// ```
2706 ///
2707 /// If `carry` is zero, this is similar to [`overflowing_mul`](Self::overflowing_mul),
2708 /// except that it gives the value of the overflow instead of just whether one happened:
2709 ///
2710 /// ```
2711 /// #![feature(bigint_helper_methods)]
2712 /// let r = u8::carrying_mul(7, 13, 0);
2713 /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(7, 13));
2714 /// let r = u8::carrying_mul(13, 42, 0);
2715 /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(13, 42));
2716 /// ```
2717 ///
2718 /// The value of the first field in the returned tuple matches what you'd get
2719 /// by combining the [`wrapping_mul`](Self::wrapping_mul) and
2720 /// [`wrapping_add`](Self::wrapping_add) methods:
2721 ///
2722 /// ```
2723 /// #![feature(bigint_helper_methods)]
2724 /// assert_eq!(
2725 /// 789_u16.carrying_mul(456, 123).0,
2726 /// 789_u16.wrapping_mul(456).wrapping_add(123),
2727 /// );
2728 /// ```
2729 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2730 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2731 #[must_use = "this returns the result of the operation, \
2732 without modifying the original"]
2733 #[inline]
2734 pub const fn carrying_mul(self, rhs: Self, carry: Self) -> (Self, Self) {
2735 Self::carrying_mul_add(self, rhs, carry, 0)
2736 }
2737
2738 /// Calculates the "full multiplication" `self * rhs + carry1 + carry2`
2739 /// without the possibility to overflow.
2740 ///
2741 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2742 /// of the result as two separate values, in that order.
2743 ///
2744 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2745 /// additional amount of overflow. This allows for chaining together multiple
2746 /// multiplications to create "big integers" which represent larger values.
2747 ///
2748 /// If you don't need either `carry`, then you can use [`Self::widening_mul`] instead,
2749 /// and if you only need one `carry`, then you can use [`Self::carrying_mul`] instead.
2750 ///
2751 /// # Examples
2752 ///
2753 /// Please note that this example is shared between integer types,
2754 /// which explains why `u32` is used here.
2755 ///
2756 /// ```
2757 /// #![feature(bigint_helper_methods)]
2758 /// assert_eq!(5u32.carrying_mul_add(2, 0, 0), (10, 0));
2759 /// assert_eq!(5u32.carrying_mul_add(2, 10, 10), (30, 0));
2760 /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 0, 0), (1410065408, 2));
2761 /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 10, 10), (1410065428, 2));
2762 #[doc = concat!("assert_eq!(",
2763 stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2764 "(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX));"
2765 )]
2766 /// ```
2767 ///
2768 /// This is the core per-digit operation for "grade school" O(n²) multiplication.
2769 ///
2770 /// Please note that this example is shared between integer types,
2771 /// using `u8` for simplicity of the demonstration.
2772 ///
2773 /// ```
2774 /// #![feature(bigint_helper_methods)]
2775 ///
2776 /// fn quadratic_mul<const N: usize>(a: [u8; N], b: [u8; N]) -> [u8; N] {
2777 /// let mut out = [0; N];
2778 /// for j in 0..N {
2779 /// let mut carry = 0;
2780 /// for i in 0..(N - j) {
2781 /// (out[j + i], carry) = u8::carrying_mul_add(a[i], b[j], out[j + i], carry);
2782 /// }
2783 /// }
2784 /// out
2785 /// }
2786 ///
2787 /// // -1 * -1 == 1
2788 /// assert_eq!(quadratic_mul([0xFF; 3], [0xFF; 3]), [1, 0, 0]);
2789 ///
2790 /// assert_eq!(u32::wrapping_mul(0x9e3779b9, 0x7f4a7c15), 0xCFFC982D);
2791 /// assert_eq!(
2792 /// quadratic_mul(u32::to_le_bytes(0x9e3779b9), u32::to_le_bytes(0x7f4a7c15)),
2793 /// u32::to_le_bytes(0xCFFC982D)
2794 /// );
2795 /// ```
2796 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2797 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2798 #[must_use = "this returns the result of the operation, \
2799 without modifying the original"]
2800 #[inline]
2801 pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> (Self, Self) {
2802 intrinsics::carrying_mul_add(self, rhs, carry, add)
2803 }
2804
2805 /// Calculates the divisor when `self` is divided by `rhs`.
2806 ///
2807 /// Returns a tuple of the divisor along with a boolean indicating
2808 /// whether an arithmetic overflow would occur. Note that for unsigned
2809 /// integers overflow never occurs, so the second value is always
2810 /// `false`.
2811 ///
2812 /// # Panics
2813 ///
2814 /// This function will panic if `rhs` is zero.
2815 ///
2816 /// # Examples
2817 ///
2818 /// ```
2819 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
2820 /// ```
2821 #[inline(always)]
2822 #[stable(feature = "wrapping", since = "1.7.0")]
2823 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2824 #[must_use = "this returns the result of the operation, \
2825 without modifying the original"]
2826 #[track_caller]
2827 pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
2828 (self / rhs, false)
2829 }
2830
2831 /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`.
2832 ///
2833 /// Returns a tuple of the divisor along with a boolean indicating
2834 /// whether an arithmetic overflow would occur. Note that for unsigned
2835 /// integers overflow never occurs, so the second value is always
2836 /// `false`.
2837 /// Since, for the positive integers, all common
2838 /// definitions of division are equal, this
2839 /// is exactly equal to `self.overflowing_div(rhs)`.
2840 ///
2841 /// # Panics
2842 ///
2843 /// This function will panic if `rhs` is zero.
2844 ///
2845 /// # Examples
2846 ///
2847 /// ```
2848 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
2849 /// ```
2850 #[inline(always)]
2851 #[stable(feature = "euclidean_division", since = "1.38.0")]
2852 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2853 #[must_use = "this returns the result of the operation, \
2854 without modifying the original"]
2855 #[track_caller]
2856 pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
2857 (self / rhs, false)
2858 }
2859
2860 /// Calculates the remainder when `self` is divided by `rhs`.
2861 ///
2862 /// Returns a tuple of the remainder after dividing along with a boolean
2863 /// indicating whether an arithmetic overflow would occur. Note that for
2864 /// unsigned integers overflow never occurs, so the second value is
2865 /// always `false`.
2866 ///
2867 /// # Panics
2868 ///
2869 /// This function will panic if `rhs` is zero.
2870 ///
2871 /// # Examples
2872 ///
2873 /// ```
2874 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
2875 /// ```
2876 #[inline(always)]
2877 #[stable(feature = "wrapping", since = "1.7.0")]
2878 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2879 #[must_use = "this returns the result of the operation, \
2880 without modifying the original"]
2881 #[track_caller]
2882 pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
2883 (self % rhs, false)
2884 }
2885
2886 /// Calculates the remainder `self.rem_euclid(rhs)` as if by Euclidean division.
2887 ///
2888 /// Returns a tuple of the modulo after dividing along with a boolean
2889 /// indicating whether an arithmetic overflow would occur. Note that for
2890 /// unsigned integers overflow never occurs, so the second value is
2891 /// always `false`.
2892 /// Since, for the positive integers, all common
2893 /// definitions of division are equal, this operation
2894 /// is exactly equal to `self.overflowing_rem(rhs)`.
2895 ///
2896 /// # Panics
2897 ///
2898 /// This function will panic if `rhs` is zero.
2899 ///
2900 /// # Examples
2901 ///
2902 /// ```
2903 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
2904 /// ```
2905 #[inline(always)]
2906 #[stable(feature = "euclidean_division", since = "1.38.0")]
2907 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2908 #[must_use = "this returns the result of the operation, \
2909 without modifying the original"]
2910 #[track_caller]
2911 pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
2912 (self % rhs, false)
2913 }
2914
2915 /// Negates self in an overflowing fashion.
2916 ///
2917 /// Returns `!self + 1` using wrapping operations to return the value
2918 /// that represents the negation of this unsigned value. Note that for
2919 /// positive unsigned values overflow always occurs, but negating 0 does
2920 /// not overflow.
2921 ///
2922 /// # Examples
2923 ///
2924 /// ```
2925 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false));")]
2926 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), ", true));")]
2927 /// ```
2928 #[inline(always)]
2929 #[stable(feature = "wrapping", since = "1.7.0")]
2930 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2931 #[must_use = "this returns the result of the operation, \
2932 without modifying the original"]
2933 pub const fn overflowing_neg(self) -> (Self, bool) {
2934 ((!self).wrapping_add(1), self != 0)
2935 }
2936
2937 /// Shifts self left by `rhs` bits.
2938 ///
2939 /// Returns a tuple of the shifted version of self along with a boolean
2940 /// indicating whether the shift value was larger than or equal to the
2941 /// number of bits. If the shift value is too large, then value is
2942 /// masked (N-1) where N is the number of bits, and this value is then
2943 /// used to perform the shift.
2944 ///
2945 /// # Examples
2946 ///
2947 /// ```
2948 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")]
2949 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));")]
2950 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
2951 /// ```
2952 #[stable(feature = "wrapping", since = "1.7.0")]
2953 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2954 #[must_use = "this returns the result of the operation, \
2955 without modifying the original"]
2956 #[inline(always)]
2957 pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
2958 (self.wrapping_shl(rhs), rhs >= Self::BITS)
2959 }
2960
2961 /// Shifts self right by `rhs` bits.
2962 ///
2963 /// Returns a tuple of the shifted version of self along with a boolean
2964 /// indicating whether the shift value was larger than or equal to the
2965 /// number of bits. If the shift value is too large, then value is
2966 /// masked (N-1) where N is the number of bits, and this value is then
2967 /// used to perform the shift.
2968 ///
2969 /// # Examples
2970 ///
2971 /// ```
2972 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
2973 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));")]
2974 /// ```
2975 #[stable(feature = "wrapping", since = "1.7.0")]
2976 #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")]
2977 #[must_use = "this returns the result of the operation, \
2978 without modifying the original"]
2979 #[inline(always)]
2980 pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
2981 (self.wrapping_shr(rhs), rhs >= Self::BITS)
2982 }
2983
2984 /// Raises self to the power of `exp`, using exponentiation by squaring.
2985 ///
2986 /// Returns a tuple of the exponentiation along with a bool indicating
2987 /// whether an overflow happened.
2988 ///
2989 /// # Examples
2990 ///
2991 /// ```
2992 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")]
2993 /// assert_eq!(3u8.overflowing_pow(6), (217, true));
2994 /// ```
2995 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2996 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2997 #[must_use = "this returns the result of the operation, \
2998 without modifying the original"]
2999 #[inline]
3000 pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
3001 if exp == 0{
3002 return (1,false);
3003 }
3004 let mut base = self;
3005 let mut acc: Self = 1;
3006 let mut overflown = false;
3007 // Scratch space for storing results of overflowing_mul.
3008 let mut r;
3009
3010 loop {
3011 if (exp & 1) == 1 {
3012 r = acc.overflowing_mul(base);
3013 // since exp!=0, finally the exp must be 1.
3014 if exp == 1 {
3015 r.1 |= overflown;
3016 return r;
3017 }
3018 acc = r.0;
3019 overflown |= r.1;
3020 }
3021 exp /= 2;
3022 r = base.overflowing_mul(base);
3023 base = r.0;
3024 overflown |= r.1;
3025 }
3026 }
3027
3028 /// Raises self to the power of `exp`, using exponentiation by squaring.
3029 ///
3030 /// # Examples
3031 ///
3032 /// ```
3033 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")]
3034 /// ```
3035 #[stable(feature = "rust1", since = "1.0.0")]
3036 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3037 #[must_use = "this returns the result of the operation, \
3038 without modifying the original"]
3039 #[inline]
3040 #[rustc_inherit_overflow_checks]
3041 pub const fn pow(self, mut exp: u32) -> Self {
3042 if exp == 0 {
3043 return 1;
3044 }
3045 let mut base = self;
3046 let mut acc = 1;
3047
3048 if intrinsics::is_val_statically_known(exp) {
3049 while exp > 1 {
3050 if (exp & 1) == 1 {
3051 acc = acc * base;
3052 }
3053 exp /= 2;
3054 base = base * base;
3055 }
3056
3057 // since exp!=0, finally the exp must be 1.
3058 // Deal with the final bit of the exponent separately, since
3059 // squaring the base afterwards is not necessary and may cause a
3060 // needless overflow.
3061 acc * base
3062 } else {
3063 // This is faster than the above when the exponent is not known
3064 // at compile time. We can't use the same code for the constant
3065 // exponent case because LLVM is currently unable to unroll
3066 // this loop.
3067 loop {
3068 if (exp & 1) == 1 {
3069 acc = acc * base;
3070 // since exp!=0, finally the exp must be 1.
3071 if exp == 1 {
3072 return acc;
3073 }
3074 }
3075 exp /= 2;
3076 base = base * base;
3077 }
3078 }
3079 }
3080
3081 /// Returns the square root of the number, rounded down.
3082 ///
3083 /// # Examples
3084 ///
3085 /// ```
3086 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
3087 /// ```
3088 #[stable(feature = "isqrt", since = "1.84.0")]
3089 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
3090 #[must_use = "this returns the result of the operation, \
3091 without modifying the original"]
3092 #[inline]
3093 pub const fn isqrt(self) -> Self {
3094 let result = crate::num::int_sqrt::$ActualT(self as $ActualT) as $SelfT;
3095
3096 // Inform the optimizer what the range of outputs is. If testing
3097 // `core` crashes with no panic message and a `num::int_sqrt::u*`
3098 // test failed, it's because your edits caused these assertions or
3099 // the assertions in `fn isqrt` of `nonzero.rs` to become false.
3100 //
3101 // SAFETY: Integer square root is a monotonically nondecreasing
3102 // function, which means that increasing the input will never
3103 // cause the output to decrease. Thus, since the input for unsigned
3104 // integers is bounded by `[0, <$ActualT>::MAX]`, sqrt(n) will be
3105 // bounded by `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
3106 unsafe {
3107 const MAX_RESULT: $SelfT = crate::num::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT;
3108 crate::hint::assert_unchecked(result <= MAX_RESULT);
3109 }
3110
3111 result
3112 }
3113
3114 /// Performs Euclidean division.
3115 ///
3116 /// Since, for the positive integers, all common
3117 /// definitions of division are equal, this
3118 /// is exactly equal to `self / rhs`.
3119 ///
3120 /// # Panics
3121 ///
3122 /// This function will panic if `rhs` is zero.
3123 ///
3124 /// # Examples
3125 ///
3126 /// ```
3127 #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")]
3128 /// ```
3129 #[stable(feature = "euclidean_division", since = "1.38.0")]
3130 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3131 #[must_use = "this returns the result of the operation, \
3132 without modifying the original"]
3133 #[inline(always)]
3134 #[track_caller]
3135 pub const fn div_euclid(self, rhs: Self) -> Self {
3136 self / rhs
3137 }
3138
3139
3140 /// Calculates the least remainder of `self (mod rhs)`.
3141 ///
3142 /// Since, for the positive integers, all common
3143 /// definitions of division are equal, this
3144 /// is exactly equal to `self % rhs`.
3145 ///
3146 /// # Panics
3147 ///
3148 /// This function will panic if `rhs` is zero.
3149 ///
3150 /// # Examples
3151 ///
3152 /// ```
3153 #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type")]
3154 /// ```
3155 #[doc(alias = "modulo", alias = "mod")]
3156 #[stable(feature = "euclidean_division", since = "1.38.0")]
3157 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3158 #[must_use = "this returns the result of the operation, \
3159 without modifying the original"]
3160 #[inline(always)]
3161 #[track_caller]
3162 pub const fn rem_euclid(self, rhs: Self) -> Self {
3163 self % rhs
3164 }
3165
3166 /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
3167 ///
3168 /// This is the same as performing `self / rhs` for all unsigned integers.
3169 ///
3170 /// # Panics
3171 ///
3172 /// This function will panic if `rhs` is zero.
3173 ///
3174 /// # Examples
3175 ///
3176 /// ```
3177 /// #![feature(int_roundings)]
3178 #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")]
3179 /// ```
3180 #[unstable(feature = "int_roundings", issue = "88581")]
3181 #[must_use = "this returns the result of the operation, \
3182 without modifying the original"]
3183 #[inline(always)]
3184 #[track_caller]
3185 pub const fn div_floor(self, rhs: Self) -> Self {
3186 self / rhs
3187 }
3188
3189 /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
3190 ///
3191 /// # Panics
3192 ///
3193 /// This function will panic if `rhs` is zero.
3194 ///
3195 /// # Examples
3196 ///
3197 /// ```
3198 #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")]
3199 /// ```
3200 #[stable(feature = "int_roundings1", since = "1.73.0")]
3201 #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3202 #[must_use = "this returns the result of the operation, \
3203 without modifying the original"]
3204 #[inline]
3205 #[track_caller]
3206 pub const fn div_ceil(self, rhs: Self) -> Self {
3207 let d = self / rhs;
3208 let r = self % rhs;
3209 if r > 0 {
3210 d + 1
3211 } else {
3212 d
3213 }
3214 }
3215
3216 /// Calculates the smallest value greater than or equal to `self` that
3217 /// is a multiple of `rhs`.
3218 ///
3219 /// # Panics
3220 ///
3221 /// This function will panic if `rhs` is zero.
3222 ///
3223 /// ## Overflow behavior
3224 ///
3225 /// On overflow, this function will panic if overflow checks are enabled (default in debug
3226 /// mode) and wrap if overflow checks are disabled (default in release mode).
3227 ///
3228 /// # Examples
3229 ///
3230 /// ```
3231 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
3232 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
3233 /// ```
3234 #[stable(feature = "int_roundings1", since = "1.73.0")]
3235 #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3236 #[must_use = "this returns the result of the operation, \
3237 without modifying the original"]
3238 #[inline]
3239 #[rustc_inherit_overflow_checks]
3240 pub const fn next_multiple_of(self, rhs: Self) -> Self {
3241 match self % rhs {
3242 0 => self,
3243 r => self + (rhs - r)
3244 }
3245 }
3246
3247 /// Calculates the smallest value greater than or equal to `self` that
3248 /// is a multiple of `rhs`. Returns `None` if `rhs` is zero or the
3249 /// operation would result in overflow.
3250 ///
3251 /// # Examples
3252 ///
3253 /// ```
3254 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
3255 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
3256 #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
3257 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
3258 /// ```
3259 #[stable(feature = "int_roundings1", since = "1.73.0")]
3260 #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")]
3261 #[must_use = "this returns the result of the operation, \
3262 without modifying the original"]
3263 #[inline]
3264 pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
3265 match try_opt!(self.checked_rem(rhs)) {
3266 0 => Some(self),
3267 // rhs - r cannot overflow because r is smaller than rhs
3268 r => self.checked_add(rhs - r)
3269 }
3270 }
3271
3272 /// Returns `true` if `self` is an integer multiple of `rhs`, and false otherwise.
3273 ///
3274 /// This function is equivalent to `self % rhs == 0`, except that it will not panic
3275 /// for `rhs == 0`. Instead, `0.is_multiple_of(0) == true`, and for any non-zero `n`,
3276 /// `n.is_multiple_of(0) == false`.
3277 ///
3278 /// # Examples
3279 ///
3280 /// ```
3281 #[doc = concat!("assert!(6_", stringify!($SelfT), ".is_multiple_of(2));")]
3282 #[doc = concat!("assert!(!5_", stringify!($SelfT), ".is_multiple_of(2));")]
3283 ///
3284 #[doc = concat!("assert!(0_", stringify!($SelfT), ".is_multiple_of(0));")]
3285 #[doc = concat!("assert!(!6_", stringify!($SelfT), ".is_multiple_of(0));")]
3286 /// ```
3287 #[stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
3288 #[rustc_const_stable(feature = "unsigned_is_multiple_of", since = "1.87.0")]
3289 #[must_use]
3290 #[inline]
3291 #[rustc_inherit_overflow_checks]
3292 pub const fn is_multiple_of(self, rhs: Self) -> bool {
3293 match rhs {
3294 0 => self == 0,
3295 _ => self % rhs == 0,
3296 }
3297 }
3298
3299 /// Returns `true` if and only if `self == 2^k` for some unsigned integer `k`.
3300 ///
3301 /// # Examples
3302 ///
3303 /// ```
3304 #[doc = concat!("assert!(16", stringify!($SelfT), ".is_power_of_two());")]
3305 #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_power_of_two());")]
3306 /// ```
3307 #[must_use]
3308 #[stable(feature = "rust1", since = "1.0.0")]
3309 #[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")]
3310 #[inline(always)]
3311 pub const fn is_power_of_two(self) -> bool {
3312 self.count_ones() == 1
3313 }
3314
3315 // Returns one less than next power of two.
3316 // (For 8u8 next power of two is 8u8 and for 6u8 it is 8u8)
3317 //
3318 // 8u8.one_less_than_next_power_of_two() == 7
3319 // 6u8.one_less_than_next_power_of_two() == 7
3320 //
3321 // This method cannot overflow, as in the `next_power_of_two`
3322 // overflow cases it instead ends up returning the maximum value
3323 // of the type, and can return 0 for 0.
3324 #[inline]
3325 const fn one_less_than_next_power_of_two(self) -> Self {
3326 if self <= 1 { return 0; }
3327
3328 let p = self - 1;
3329 // SAFETY: Because `p > 0`, it cannot consist entirely of leading zeros.
3330 // That means the shift is always in-bounds, and some processors
3331 // (such as intel pre-haswell) have more efficient ctlz
3332 // intrinsics when the argument is non-zero.
3333 let z = unsafe { intrinsics::ctlz_nonzero(p) };
3334 <$SelfT>::MAX >> z
3335 }
3336
3337 /// Returns the smallest power of two greater than or equal to `self`.
3338 ///
3339 /// When return value overflows (i.e., `self > (1 << (N-1))` for type
3340 /// `uN`), it panics in debug mode and the return value is wrapped to 0 in
3341 /// release mode (the only situation in which this method can return 0).
3342 ///
3343 /// # Examples
3344 ///
3345 /// ```
3346 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")]
3347 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")]
3348 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".next_power_of_two(), 1);")]
3349 /// ```
3350 #[stable(feature = "rust1", since = "1.0.0")]
3351 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3352 #[must_use = "this returns the result of the operation, \
3353 without modifying the original"]
3354 #[inline]
3355 #[rustc_inherit_overflow_checks]
3356 pub const fn next_power_of_two(self) -> Self {
3357 self.one_less_than_next_power_of_two() + 1
3358 }
3359
3360 /// Returns the smallest power of two greater than or equal to `self`. If
3361 /// the next power of two is greater than the type's maximum value,
3362 /// `None` is returned, otherwise the power of two is wrapped in `Some`.
3363 ///
3364 /// # Examples
3365 ///
3366 /// ```
3367 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_next_power_of_two(), Some(2));")]
3368 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));")]
3369 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);")]
3370 /// ```
3371 #[inline]
3372 #[stable(feature = "rust1", since = "1.0.0")]
3373 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3374 #[must_use = "this returns the result of the operation, \
3375 without modifying the original"]
3376 pub const fn checked_next_power_of_two(self) -> Option<Self> {
3377 self.one_less_than_next_power_of_two().checked_add(1)
3378 }
3379
3380 /// Returns the smallest power of two greater than or equal to `n`. If
3381 /// the next power of two is greater than the type's maximum value,
3382 /// the return value is wrapped to `0`.
3383 ///
3384 /// # Examples
3385 ///
3386 /// ```
3387 /// #![feature(wrapping_next_power_of_two)]
3388 ///
3389 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);")]
3390 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);")]
3391 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);")]
3392 /// ```
3393 #[inline]
3394 #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
3395 reason = "needs decision on wrapping behavior")]
3396 #[must_use = "this returns the result of the operation, \
3397 without modifying the original"]
3398 pub const fn wrapping_next_power_of_two(self) -> Self {
3399 self.one_less_than_next_power_of_two().wrapping_add(1)
3400 }
3401
3402 /// Returns the memory representation of this integer as a byte array in
3403 /// big-endian (network) byte order.
3404 ///
3405 #[doc = $to_xe_bytes_doc]
3406 ///
3407 /// # Examples
3408 ///
3409 /// ```
3410 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
3411 #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
3412 /// ```
3413 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3414 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3415 #[must_use = "this returns the result of the operation, \
3416 without modifying the original"]
3417 #[inline]
3418 pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] {
3419 self.to_be().to_ne_bytes()
3420 }
3421
3422 /// Returns the memory representation of this integer as a byte array in
3423 /// little-endian byte order.
3424 ///
3425 #[doc = $to_xe_bytes_doc]
3426 ///
3427 /// # Examples
3428 ///
3429 /// ```
3430 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
3431 #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
3432 /// ```
3433 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3434 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3435 #[must_use = "this returns the result of the operation, \
3436 without modifying the original"]
3437 #[inline]
3438 pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] {
3439 self.to_le().to_ne_bytes()
3440 }
3441
3442 /// Returns the memory representation of this integer as a byte array in
3443 /// native byte order.
3444 ///
3445 /// As the target platform's native endianness is used, portable code
3446 /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
3447 /// instead.
3448 ///
3449 #[doc = $to_xe_bytes_doc]
3450 ///
3451 /// [`to_be_bytes`]: Self::to_be_bytes
3452 /// [`to_le_bytes`]: Self::to_le_bytes
3453 ///
3454 /// # Examples
3455 ///
3456 /// ```
3457 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
3458 /// assert_eq!(
3459 /// bytes,
3460 /// if cfg!(target_endian = "big") {
3461 #[doc = concat!(" ", $be_bytes)]
3462 /// } else {
3463 #[doc = concat!(" ", $le_bytes)]
3464 /// }
3465 /// );
3466 /// ```
3467 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3468 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3469 #[must_use = "this returns the result of the operation, \
3470 without modifying the original"]
3471 #[allow(unnecessary_transmutes)]
3472 // SAFETY: const sound because integers are plain old datatypes so we can always
3473 // transmute them to arrays of bytes
3474 #[inline]
3475 pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] {
3476 // SAFETY: integers are plain old datatypes so we can always transmute them to
3477 // arrays of bytes
3478 unsafe { mem::transmute(self) }
3479 }
3480
3481 /// Creates a native endian integer value from its representation
3482 /// as a byte array in big endian.
3483 ///
3484 #[doc = $from_xe_bytes_doc]
3485 ///
3486 /// # Examples
3487 ///
3488 /// ```
3489 #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
3490 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3491 /// ```
3492 ///
3493 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3494 ///
3495 /// ```
3496 #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3497 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3498 /// *input = rest;
3499 #[doc = concat!(" ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
3500 /// }
3501 /// ```
3502 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3503 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3504 #[must_use]
3505 #[inline]
3506 pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3507 Self::from_be(Self::from_ne_bytes(bytes))
3508 }
3509
3510 /// Creates a native endian integer value from its representation
3511 /// as a byte array in little endian.
3512 ///
3513 #[doc = $from_xe_bytes_doc]
3514 ///
3515 /// # Examples
3516 ///
3517 /// ```
3518 #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
3519 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3520 /// ```
3521 ///
3522 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3523 ///
3524 /// ```
3525 #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3526 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3527 /// *input = rest;
3528 #[doc = concat!(" ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
3529 /// }
3530 /// ```
3531 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3532 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3533 #[must_use]
3534 #[inline]
3535 pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3536 Self::from_le(Self::from_ne_bytes(bytes))
3537 }
3538
3539 /// Creates a native endian integer value from its memory representation
3540 /// as a byte array in native endianness.
3541 ///
3542 /// As the target platform's native endianness is used, portable code
3543 /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
3544 /// appropriate instead.
3545 ///
3546 /// [`from_be_bytes`]: Self::from_be_bytes
3547 /// [`from_le_bytes`]: Self::from_le_bytes
3548 ///
3549 #[doc = $from_xe_bytes_doc]
3550 ///
3551 /// # Examples
3552 ///
3553 /// ```
3554 #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
3555 #[doc = concat!(" ", $be_bytes, "")]
3556 /// } else {
3557 #[doc = concat!(" ", $le_bytes, "")]
3558 /// });
3559 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3560 /// ```
3561 ///
3562 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3563 ///
3564 /// ```
3565 #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3566 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3567 /// *input = rest;
3568 #[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
3569 /// }
3570 /// ```
3571 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3572 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3573 #[allow(unnecessary_transmutes)]
3574 #[must_use]
3575 // SAFETY: const sound because integers are plain old datatypes so we can always
3576 // transmute to them
3577 #[inline]
3578 pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3579 // SAFETY: integers are plain old datatypes so we can always transmute to them
3580 unsafe { mem::transmute(bytes) }
3581 }
3582
3583 /// New code should prefer to use
3584 #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
3585 ///
3586 /// Returns the smallest value that can be represented by this integer type.
3587 #[stable(feature = "rust1", since = "1.0.0")]
3588 #[rustc_promotable]
3589 #[inline(always)]
3590 #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
3591 #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
3592 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
3593 pub const fn min_value() -> Self { Self::MIN }
3594
3595 /// New code should prefer to use
3596 #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
3597 ///
3598 /// Returns the largest value that can be represented by this integer type.
3599 #[stable(feature = "rust1", since = "1.0.0")]
3600 #[rustc_promotable]
3601 #[inline(always)]
3602 #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
3603 #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
3604 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
3605 pub const fn max_value() -> Self { Self::MAX }
3606 }
3607}