core/num/int_macros.rs
1macro_rules! int_impl {
2 (
3 Self = $SelfT:ty,
4 ActualT = $ActualT:ident,
5 UnsignedT = $UnsignedT:ty,
6
7 // There 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 Min = $Min:literal,
14 Max = $Max:literal,
15 rot = $rot:literal,
16 rot_op = $rot_op:literal,
17 rot_result = $rot_result:literal,
18 swap_op = $swap_op:literal,
19 swapped = $swapped:literal,
20 reversed = $reversed:literal,
21 le_bytes = $le_bytes:literal,
22 be_bytes = $be_bytes:literal,
23 to_xe_bytes_doc = $to_xe_bytes_doc:expr,
24 from_xe_bytes_doc = $from_xe_bytes_doc:expr,
25 bound_condition = $bound_condition:literal,
26 ) => {
27 /// The smallest value that can be represented by this integer type
28 #[doc = concat!("(−2<sup>", $BITS_MINUS_ONE, "</sup>", $bound_condition, ").")]
29 ///
30 /// # Examples
31 ///
32 /// Basic usage:
33 ///
34 /// ```
35 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, ", stringify!($Min), ");")]
36 /// ```
37 #[stable(feature = "assoc_int_consts", since = "1.43.0")]
38 pub const MIN: Self = !Self::MAX;
39
40 /// The largest value that can be represented by this integer type
41 #[doc = concat!("(2<sup>", $BITS_MINUS_ONE, "</sup> − 1", $bound_condition, ").")]
42 ///
43 /// # Examples
44 ///
45 /// Basic usage:
46 ///
47 /// ```
48 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($Max), ");")]
49 /// ```
50 #[stable(feature = "assoc_int_consts", since = "1.43.0")]
51 pub const MAX: Self = (<$UnsignedT>::MAX >> 1) as Self;
52
53 /// The size of this integer type in bits.
54 ///
55 /// # Examples
56 ///
57 /// ```
58 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
59 /// ```
60 #[stable(feature = "int_bits_const", since = "1.53.0")]
61 pub const BITS: u32 = <$UnsignedT>::BITS;
62
63 /// Returns the number of ones in the binary representation of `self`.
64 ///
65 /// # Examples
66 ///
67 /// Basic usage:
68 ///
69 /// ```
70 #[doc = concat!("let n = 0b100_0000", stringify!($SelfT), ";")]
71 ///
72 /// assert_eq!(n.count_ones(), 1);
73 /// ```
74 ///
75 #[stable(feature = "rust1", since = "1.0.0")]
76 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
77 #[doc(alias = "popcount")]
78 #[doc(alias = "popcnt")]
79 #[must_use = "this returns the result of the operation, \
80 without modifying the original"]
81 #[inline(always)]
82 pub const fn count_ones(self) -> u32 { (self as $UnsignedT).count_ones() }
83
84 /// Returns the number of zeros in the binary representation of `self`.
85 ///
86 /// # Examples
87 ///
88 /// Basic usage:
89 ///
90 /// ```
91 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.count_zeros(), 1);")]
92 /// ```
93 #[stable(feature = "rust1", since = "1.0.0")]
94 #[rustc_const_stable(feature = "const_int_methods", 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 /// Basic usage:
110 ///
111 /// ```
112 #[doc = concat!("let n = -1", stringify!($SelfT), ";")]
113 ///
114 /// assert_eq!(n.leading_zeros(), 0);
115 /// ```
116 #[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")]
117 #[stable(feature = "rust1", since = "1.0.0")]
118 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
119 #[must_use = "this returns the result of the operation, \
120 without modifying the original"]
121 #[inline(always)]
122 pub const fn leading_zeros(self) -> u32 {
123 (self as $UnsignedT).leading_zeros()
124 }
125
126 /// Returns the number of trailing zeros in the binary representation of `self`.
127 ///
128 /// # Examples
129 ///
130 /// Basic usage:
131 ///
132 /// ```
133 #[doc = concat!("let n = -4", stringify!($SelfT), ";")]
134 ///
135 /// assert_eq!(n.trailing_zeros(), 2);
136 /// ```
137 #[stable(feature = "rust1", since = "1.0.0")]
138 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
139 #[must_use = "this returns the result of the operation, \
140 without modifying the original"]
141 #[inline(always)]
142 pub const fn trailing_zeros(self) -> u32 {
143 (self as $UnsignedT).trailing_zeros()
144 }
145
146 /// Returns the number of leading ones in the binary representation of `self`.
147 ///
148 /// # Examples
149 ///
150 /// Basic usage:
151 ///
152 /// ```
153 #[doc = concat!("let n = -1", stringify!($SelfT), ";")]
154 ///
155 #[doc = concat!("assert_eq!(n.leading_ones(), ", stringify!($BITS), ");")]
156 /// ```
157 #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
158 #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
159 #[must_use = "this returns the result of the operation, \
160 without modifying the original"]
161 #[inline(always)]
162 pub const fn leading_ones(self) -> u32 {
163 (self as $UnsignedT).leading_ones()
164 }
165
166 /// Returns the number of trailing ones in the binary representation of `self`.
167 ///
168 /// # Examples
169 ///
170 /// Basic usage:
171 ///
172 /// ```
173 #[doc = concat!("let n = 3", stringify!($SelfT), ";")]
174 ///
175 /// assert_eq!(n.trailing_ones(), 2);
176 /// ```
177 #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
178 #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
179 #[must_use = "this returns the result of the operation, \
180 without modifying the original"]
181 #[inline(always)]
182 pub const fn trailing_ones(self) -> u32 {
183 (self as $UnsignedT).trailing_ones()
184 }
185
186 /// Returns the bit pattern of `self` reinterpreted as an unsigned integer of the same size.
187 ///
188 /// This produces the same result as an `as` cast, but ensures that the bit-width remains
189 /// the same.
190 ///
191 /// # Examples
192 ///
193 /// Basic usage:
194 ///
195 /// ```
196 /// #![feature(integer_sign_cast)]
197 ///
198 #[doc = concat!("let n = -1", stringify!($SelfT), ";")]
199 ///
200 #[doc = concat!("assert_eq!(n.cast_unsigned(), ", stringify!($UnsignedT), "::MAX);")]
201 /// ```
202 #[unstable(feature = "integer_sign_cast", issue = "125882")]
203 #[must_use = "this returns the result of the operation, \
204 without modifying the original"]
205 #[inline(always)]
206 pub const fn cast_unsigned(self) -> $UnsignedT {
207 self as $UnsignedT
208 }
209
210 /// Shifts the bits to the left by a specified amount, `n`,
211 /// wrapping the truncated bits to the end of the resulting integer.
212 ///
213 /// Please note this isn't the same operation as the `<<` shifting operator!
214 ///
215 /// # Examples
216 ///
217 /// Basic usage:
218 ///
219 /// ```
220 #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
221 #[doc = concat!("let m = ", $rot_result, ";")]
222 ///
223 #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
224 /// ```
225 #[stable(feature = "rust1", since = "1.0.0")]
226 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
227 #[must_use = "this returns the result of the operation, \
228 without modifying the original"]
229 #[inline(always)]
230 pub const fn rotate_left(self, n: u32) -> Self {
231 (self as $UnsignedT).rotate_left(n) as Self
232 }
233
234 /// Shifts the bits to the right by a specified amount, `n`,
235 /// wrapping the truncated bits to the beginning of the resulting
236 /// integer.
237 ///
238 /// Please note this isn't the same operation as the `>>` shifting operator!
239 ///
240 /// # Examples
241 ///
242 /// Basic usage:
243 ///
244 /// ```
245 #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
246 #[doc = concat!("let m = ", $rot_op, ";")]
247 ///
248 #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
249 /// ```
250 #[stable(feature = "rust1", since = "1.0.0")]
251 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
252 #[must_use = "this returns the result of the operation, \
253 without modifying the original"]
254 #[inline(always)]
255 pub const fn rotate_right(self, n: u32) -> Self {
256 (self as $UnsignedT).rotate_right(n) as Self
257 }
258
259 /// Reverses the byte order of the integer.
260 ///
261 /// # Examples
262 ///
263 /// Basic usage:
264 ///
265 /// ```
266 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
267 ///
268 /// let m = n.swap_bytes();
269 ///
270 #[doc = concat!("assert_eq!(m, ", $swapped, ");")]
271 /// ```
272 #[stable(feature = "rust1", since = "1.0.0")]
273 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
274 #[must_use = "this returns the result of the operation, \
275 without modifying the original"]
276 #[inline(always)]
277 pub const fn swap_bytes(self) -> Self {
278 (self as $UnsignedT).swap_bytes() as Self
279 }
280
281 /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
282 /// second least-significant bit becomes second most-significant bit, etc.
283 ///
284 /// # Examples
285 ///
286 /// Basic usage:
287 ///
288 /// ```
289 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
290 /// let m = n.reverse_bits();
291 ///
292 #[doc = concat!("assert_eq!(m, ", $reversed, ");")]
293 #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
294 /// ```
295 #[stable(feature = "reverse_bits", since = "1.37.0")]
296 #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
297 #[must_use = "this returns the result of the operation, \
298 without modifying the original"]
299 #[inline(always)]
300 pub const fn reverse_bits(self) -> Self {
301 (self as $UnsignedT).reverse_bits() as Self
302 }
303
304 /// Converts an integer from big endian to the target's endianness.
305 ///
306 /// On big endian this is a no-op. On little endian the bytes are swapped.
307 ///
308 /// # Examples
309 ///
310 /// Basic usage:
311 ///
312 /// ```
313 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
314 ///
315 /// if cfg!(target_endian = "big") {
316 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
317 /// } else {
318 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
319 /// }
320 /// ```
321 #[stable(feature = "rust1", since = "1.0.0")]
322 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
323 #[must_use]
324 #[inline]
325 pub const fn from_be(x: Self) -> Self {
326 #[cfg(target_endian = "big")]
327 {
328 x
329 }
330 #[cfg(not(target_endian = "big"))]
331 {
332 x.swap_bytes()
333 }
334 }
335
336 /// Converts an integer from little endian to the target's endianness.
337 ///
338 /// On little endian this is a no-op. On big endian the bytes are swapped.
339 ///
340 /// # Examples
341 ///
342 /// Basic usage:
343 ///
344 /// ```
345 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
346 ///
347 /// if cfg!(target_endian = "little") {
348 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
349 /// } else {
350 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
351 /// }
352 /// ```
353 #[stable(feature = "rust1", since = "1.0.0")]
354 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
355 #[must_use]
356 #[inline]
357 pub const fn from_le(x: Self) -> Self {
358 #[cfg(target_endian = "little")]
359 {
360 x
361 }
362 #[cfg(not(target_endian = "little"))]
363 {
364 x.swap_bytes()
365 }
366 }
367
368 /// Converts `self` to big endian from the target's endianness.
369 ///
370 /// On big endian this is a no-op. On little endian the bytes are swapped.
371 ///
372 /// # Examples
373 ///
374 /// Basic usage:
375 ///
376 /// ```
377 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
378 ///
379 /// if cfg!(target_endian = "big") {
380 /// assert_eq!(n.to_be(), n)
381 /// } else {
382 /// assert_eq!(n.to_be(), n.swap_bytes())
383 /// }
384 /// ```
385 #[stable(feature = "rust1", since = "1.0.0")]
386 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
387 #[must_use = "this returns the result of the operation, \
388 without modifying the original"]
389 #[inline]
390 pub const fn to_be(self) -> Self { // or not to be?
391 #[cfg(target_endian = "big")]
392 {
393 self
394 }
395 #[cfg(not(target_endian = "big"))]
396 {
397 self.swap_bytes()
398 }
399 }
400
401 /// Converts `self` to little endian from the target's endianness.
402 ///
403 /// On little endian this is a no-op. On big endian the bytes are swapped.
404 ///
405 /// # Examples
406 ///
407 /// Basic usage:
408 ///
409 /// ```
410 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
411 ///
412 /// if cfg!(target_endian = "little") {
413 /// assert_eq!(n.to_le(), n)
414 /// } else {
415 /// assert_eq!(n.to_le(), n.swap_bytes())
416 /// }
417 /// ```
418 #[stable(feature = "rust1", since = "1.0.0")]
419 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
420 #[must_use = "this returns the result of the operation, \
421 without modifying the original"]
422 #[inline]
423 pub const fn to_le(self) -> Self {
424 #[cfg(target_endian = "little")]
425 {
426 self
427 }
428 #[cfg(not(target_endian = "little"))]
429 {
430 self.swap_bytes()
431 }
432 }
433
434 /// Checked integer addition. Computes `self + rhs`, returning `None`
435 /// if overflow occurred.
436 ///
437 /// # Examples
438 ///
439 /// Basic usage:
440 ///
441 /// ```
442 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), Some(", stringify!($SelfT), "::MAX - 1));")]
443 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
444 /// ```
445 #[stable(feature = "rust1", since = "1.0.0")]
446 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
447 #[must_use = "this returns the result of the operation, \
448 without modifying the original"]
449 #[inline]
450 pub const fn checked_add(self, rhs: Self) -> Option<Self> {
451 let (a, b) = self.overflowing_add(rhs);
452 if intrinsics::unlikely(b) { None } else { Some(a) }
453 }
454
455 /// Strict integer addition. Computes `self + rhs`, panicking
456 /// if overflow occurred.
457 ///
458 /// # Panics
459 ///
460 /// ## Overflow behavior
461 ///
462 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
463 ///
464 /// # Examples
465 ///
466 /// Basic usage:
467 ///
468 /// ```
469 /// #![feature(strict_overflow_ops)]
470 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
471 /// ```
472 ///
473 /// The following panics because of overflow:
474 ///
475 /// ```should_panic
476 /// #![feature(strict_overflow_ops)]
477 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
478 /// ```
479 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
480 #[must_use = "this returns the result of the operation, \
481 without modifying the original"]
482 #[inline]
483 #[track_caller]
484 pub const fn strict_add(self, rhs: Self) -> Self {
485 let (a, b) = self.overflowing_add(rhs);
486 if b { overflow_panic::add() } else { a }
487 }
488
489 /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
490 /// cannot occur.
491 ///
492 /// Calling `x.unchecked_add(y)` is semantically equivalent to calling
493 /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
494 ///
495 /// If you're just trying to avoid the panic in debug mode, then **do not**
496 /// use this. Instead, you're looking for [`wrapping_add`].
497 ///
498 /// # Safety
499 ///
500 /// This results in undefined behavior when
501 #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
502 /// i.e. when [`checked_add`] would return `None`.
503 ///
504 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
505 #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
506 #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
507 #[stable(feature = "unchecked_math", since = "1.79.0")]
508 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
509 #[must_use = "this returns the result of the operation, \
510 without modifying the original"]
511 #[inline(always)]
512 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
513 pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
514 assert_unsafe_precondition!(
515 check_language_ub,
516 concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
517 (
518 lhs: $SelfT = self,
519 rhs: $SelfT = rhs,
520 ) => !lhs.overflowing_add(rhs).1,
521 );
522
523 // SAFETY: this is guaranteed to be safe by the caller.
524 unsafe {
525 intrinsics::unchecked_add(self, rhs)
526 }
527 }
528
529 /// Checked addition with an unsigned integer. Computes `self + rhs`,
530 /// returning `None` if overflow occurred.
531 ///
532 /// # Examples
533 ///
534 /// Basic usage:
535 ///
536 /// ```
537 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_unsigned(2), Some(3));")]
538 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_unsigned(3), None);")]
539 /// ```
540 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
541 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
542 #[must_use = "this returns the result of the operation, \
543 without modifying the original"]
544 #[inline]
545 pub const fn checked_add_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
546 let (a, b) = self.overflowing_add_unsigned(rhs);
547 if intrinsics::unlikely(b) { None } else { Some(a) }
548 }
549
550 /// Strict addition with an unsigned integer. Computes `self + rhs`,
551 /// panicking if overflow occurred.
552 ///
553 /// # Panics
554 ///
555 /// ## Overflow behavior
556 ///
557 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
558 ///
559 /// # Examples
560 ///
561 /// Basic usage:
562 ///
563 /// ```
564 /// #![feature(strict_overflow_ops)]
565 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_unsigned(2), 3);")]
566 /// ```
567 ///
568 /// The following panics because of overflow:
569 ///
570 /// ```should_panic
571 /// #![feature(strict_overflow_ops)]
572 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_unsigned(3);")]
573 /// ```
574 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
575 #[must_use = "this returns the result of the operation, \
576 without modifying the original"]
577 #[inline]
578 #[track_caller]
579 pub const fn strict_add_unsigned(self, rhs: $UnsignedT) -> Self {
580 let (a, b) = self.overflowing_add_unsigned(rhs);
581 if b { overflow_panic::add() } else { a }
582 }
583
584 /// Checked integer subtraction. Computes `self - rhs`, returning `None` if
585 /// overflow occurred.
586 ///
587 /// # Examples
588 ///
589 /// Basic usage:
590 ///
591 /// ```
592 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(1), Some(", stringify!($SelfT), "::MIN + 1));")]
593 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(3), None);")]
594 /// ```
595 #[stable(feature = "rust1", since = "1.0.0")]
596 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
597 #[must_use = "this returns the result of the operation, \
598 without modifying the original"]
599 #[inline]
600 pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
601 let (a, b) = self.overflowing_sub(rhs);
602 if intrinsics::unlikely(b) { None } else { Some(a) }
603 }
604
605 /// Strict integer subtraction. Computes `self - rhs`, panicking if
606 /// overflow occurred.
607 ///
608 /// # Panics
609 ///
610 /// ## Overflow behavior
611 ///
612 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
613 ///
614 /// # Examples
615 ///
616 /// Basic usage:
617 ///
618 /// ```
619 /// #![feature(strict_overflow_ops)]
620 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).strict_sub(1), ", stringify!($SelfT), "::MIN + 1);")]
621 /// ```
622 ///
623 /// The following panics because of overflow:
624 ///
625 /// ```should_panic
626 /// #![feature(strict_overflow_ops)]
627 #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub(3);")]
628 /// ```
629 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
630 #[must_use = "this returns the result of the operation, \
631 without modifying the original"]
632 #[inline]
633 #[track_caller]
634 pub const fn strict_sub(self, rhs: Self) -> Self {
635 let (a, b) = self.overflowing_sub(rhs);
636 if b { overflow_panic::sub() } else { a }
637 }
638
639 /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
640 /// cannot occur.
641 ///
642 /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
643 /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
644 ///
645 /// If you're just trying to avoid the panic in debug mode, then **do not**
646 /// use this. Instead, you're looking for [`wrapping_sub`].
647 ///
648 /// # Safety
649 ///
650 /// This results in undefined behavior when
651 #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
652 /// i.e. when [`checked_sub`] would return `None`.
653 ///
654 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
655 #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
656 #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
657 #[stable(feature = "unchecked_math", since = "1.79.0")]
658 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
659 #[must_use = "this returns the result of the operation, \
660 without modifying the original"]
661 #[inline(always)]
662 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
663 pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
664 assert_unsafe_precondition!(
665 check_language_ub,
666 concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
667 (
668 lhs: $SelfT = self,
669 rhs: $SelfT = rhs,
670 ) => !lhs.overflowing_sub(rhs).1,
671 );
672
673 // SAFETY: this is guaranteed to be safe by the caller.
674 unsafe {
675 intrinsics::unchecked_sub(self, rhs)
676 }
677 }
678
679 /// Checked subtraction with an unsigned integer. Computes `self - rhs`,
680 /// returning `None` if overflow occurred.
681 ///
682 /// # Examples
683 ///
684 /// Basic usage:
685 ///
686 /// ```
687 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_unsigned(2), Some(-1));")]
688 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub_unsigned(3), None);")]
689 /// ```
690 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
691 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
692 #[must_use = "this returns the result of the operation, \
693 without modifying the original"]
694 #[inline]
695 pub const fn checked_sub_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
696 let (a, b) = self.overflowing_sub_unsigned(rhs);
697 if intrinsics::unlikely(b) { None } else { Some(a) }
698 }
699
700 /// Strict subtraction with an unsigned integer. Computes `self - rhs`,
701 /// panicking if overflow occurred.
702 ///
703 /// # Panics
704 ///
705 /// ## Overflow behavior
706 ///
707 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
708 ///
709 /// # Examples
710 ///
711 /// Basic usage:
712 ///
713 /// ```
714 /// #![feature(strict_overflow_ops)]
715 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub_unsigned(2), -1);")]
716 /// ```
717 ///
718 /// The following panics because of overflow:
719 ///
720 /// ```should_panic
721 /// #![feature(strict_overflow_ops)]
722 #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub_unsigned(3);")]
723 /// ```
724 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
725 #[must_use = "this returns the result of the operation, \
726 without modifying the original"]
727 #[inline]
728 #[track_caller]
729 pub const fn strict_sub_unsigned(self, rhs: $UnsignedT) -> Self {
730 let (a, b) = self.overflowing_sub_unsigned(rhs);
731 if b { overflow_panic::sub() } else { a }
732 }
733
734 /// Checked integer multiplication. Computes `self * rhs`, returning `None` if
735 /// overflow occurred.
736 ///
737 /// # Examples
738 ///
739 /// Basic usage:
740 ///
741 /// ```
742 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(1), Some(", stringify!($SelfT), "::MAX));")]
743 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
744 /// ```
745 #[stable(feature = "rust1", since = "1.0.0")]
746 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
747 #[must_use = "this returns the result of the operation, \
748 without modifying the original"]
749 #[inline]
750 pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
751 let (a, b) = self.overflowing_mul(rhs);
752 if intrinsics::unlikely(b) { None } else { Some(a) }
753 }
754
755 /// Strict integer multiplication. Computes `self * rhs`, panicking if
756 /// overflow occurred.
757 ///
758 /// # Panics
759 ///
760 /// ## Overflow behavior
761 ///
762 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
763 ///
764 /// # Examples
765 ///
766 /// Basic usage:
767 ///
768 /// ```
769 /// #![feature(strict_overflow_ops)]
770 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.strict_mul(1), ", stringify!($SelfT), "::MAX);")]
771 /// ```
772 ///
773 /// The following panics because of overflow:
774 ///
775 /// ``` should_panic
776 /// #![feature(strict_overflow_ops)]
777 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
778 /// ```
779 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
780 #[must_use = "this returns the result of the operation, \
781 without modifying the original"]
782 #[inline]
783 #[track_caller]
784 pub const fn strict_mul(self, rhs: Self) -> Self {
785 let (a, b) = self.overflowing_mul(rhs);
786 if b { overflow_panic::mul() } else { a }
787 }
788
789 /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
790 /// cannot occur.
791 ///
792 /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
793 /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
794 ///
795 /// If you're just trying to avoid the panic in debug mode, then **do not**
796 /// use this. Instead, you're looking for [`wrapping_mul`].
797 ///
798 /// # Safety
799 ///
800 /// This results in undefined behavior when
801 #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
802 /// i.e. when [`checked_mul`] would return `None`.
803 ///
804 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
805 #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
806 #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
807 #[stable(feature = "unchecked_math", since = "1.79.0")]
808 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
809 #[must_use = "this returns the result of the operation, \
810 without modifying the original"]
811 #[inline(always)]
812 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
813 pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
814 assert_unsafe_precondition!(
815 check_language_ub,
816 concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
817 (
818 lhs: $SelfT = self,
819 rhs: $SelfT = rhs,
820 ) => !lhs.overflowing_mul(rhs).1,
821 );
822
823 // SAFETY: this is guaranteed to be safe by the caller.
824 unsafe {
825 intrinsics::unchecked_mul(self, rhs)
826 }
827 }
828
829 /// Checked integer division. Computes `self / rhs`, returning `None` if `rhs == 0`
830 /// or the division results in overflow.
831 ///
832 /// # Examples
833 ///
834 /// Basic usage:
835 ///
836 /// ```
837 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div(-1), Some(", stringify!($Max), "));")]
838 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div(-1), None);")]
839 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div(0), None);")]
840 /// ```
841 #[stable(feature = "rust1", since = "1.0.0")]
842 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
843 #[must_use = "this returns the result of the operation, \
844 without modifying the original"]
845 #[inline]
846 pub const fn checked_div(self, rhs: Self) -> Option<Self> {
847 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
848 None
849 } else {
850 // SAFETY: div by zero and by INT_MIN have been checked above
851 Some(unsafe { intrinsics::unchecked_div(self, rhs) })
852 }
853 }
854
855 /// Strict integer division. Computes `self / rhs`, panicking
856 /// if overflow occurred.
857 ///
858 /// # Panics
859 ///
860 /// This function will panic if `rhs` is zero.
861 ///
862 /// ## Overflow behavior
863 ///
864 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
865 ///
866 /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
867 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
868 /// that is too large to represent in the type.
869 ///
870 /// # Examples
871 ///
872 /// Basic usage:
873 ///
874 /// ```
875 /// #![feature(strict_overflow_ops)]
876 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).strict_div(-1), ", stringify!($Max), ");")]
877 /// ```
878 ///
879 /// The following panics because of overflow:
880 ///
881 /// ```should_panic
882 /// #![feature(strict_overflow_ops)]
883 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_div(-1);")]
884 /// ```
885 ///
886 /// The following panics because of division by zero:
887 ///
888 /// ```should_panic
889 /// #![feature(strict_overflow_ops)]
890 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
891 /// ```
892 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
893 #[must_use = "this returns the result of the operation, \
894 without modifying the original"]
895 #[inline]
896 #[track_caller]
897 pub const fn strict_div(self, rhs: Self) -> Self {
898 let (a, b) = self.overflowing_div(rhs);
899 if b { overflow_panic::div() } else { a }
900 }
901
902 /// Checked Euclidean division. Computes `self.div_euclid(rhs)`,
903 /// returning `None` if `rhs == 0` or the division results in overflow.
904 ///
905 /// # Examples
906 ///
907 /// Basic usage:
908 ///
909 /// ```
910 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div_euclid(-1), Some(", stringify!($Max), "));")]
911 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div_euclid(-1), None);")]
912 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div_euclid(0), None);")]
913 /// ```
914 #[stable(feature = "euclidean_division", since = "1.38.0")]
915 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
916 #[must_use = "this returns the result of the operation, \
917 without modifying the original"]
918 #[inline]
919 pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
920 // Using `&` helps LLVM see that it is the same check made in division.
921 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
922 None
923 } else {
924 Some(self.div_euclid(rhs))
925 }
926 }
927
928 /// Strict Euclidean division. Computes `self.div_euclid(rhs)`, panicking
929 /// if overflow occurred.
930 ///
931 /// # Panics
932 ///
933 /// This function will panic if `rhs` is zero.
934 ///
935 /// ## Overflow behavior
936 ///
937 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
938 ///
939 /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
940 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
941 /// that is too large to represent in the type.
942 ///
943 /// # Examples
944 ///
945 /// Basic usage:
946 ///
947 /// ```
948 /// #![feature(strict_overflow_ops)]
949 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).strict_div_euclid(-1), ", stringify!($Max), ");")]
950 /// ```
951 ///
952 /// The following panics because of overflow:
953 ///
954 /// ```should_panic
955 /// #![feature(strict_overflow_ops)]
956 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_div_euclid(-1);")]
957 /// ```
958 ///
959 /// The following panics because of division by zero:
960 ///
961 /// ```should_panic
962 /// #![feature(strict_overflow_ops)]
963 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
964 /// ```
965 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
966 #[must_use = "this returns the result of the operation, \
967 without modifying the original"]
968 #[inline]
969 #[track_caller]
970 pub const fn strict_div_euclid(self, rhs: Self) -> Self {
971 let (a, b) = self.overflowing_div_euclid(rhs);
972 if b { overflow_panic::div() } else { a }
973 }
974
975 /// Checked integer remainder. Computes `self % rhs`, returning `None` if
976 /// `rhs == 0` or the division results in overflow.
977 ///
978 /// # Examples
979 ///
980 /// Basic usage:
981 ///
982 /// ```
983 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
984 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
985 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_rem(-1), None);")]
986 /// ```
987 #[stable(feature = "wrapping", since = "1.7.0")]
988 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
989 #[must_use = "this returns the result of the operation, \
990 without modifying the original"]
991 #[inline]
992 pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
993 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
994 None
995 } else {
996 // SAFETY: div by zero and by INT_MIN have been checked above
997 Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
998 }
999 }
1000
1001 /// Strict integer remainder. Computes `self % rhs`, panicking if
1002 /// the division results in overflow.
1003 ///
1004 /// # Panics
1005 ///
1006 /// This function will panic if `rhs` is zero.
1007 ///
1008 /// ## Overflow behavior
1009 ///
1010 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1011 ///
1012 /// The only case where such an overflow can occur is `x % y` for `MIN / -1` on a
1013 /// signed type (where `MIN` is the negative minimal value), which is invalid due to implementation artifacts.
1014 ///
1015 /// # Examples
1016 ///
1017 /// Basic usage:
1018 ///
1019 /// ```
1020 /// #![feature(strict_overflow_ops)]
1021 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_rem(2), 1);")]
1022 /// ```
1023 ///
1024 /// The following panics because of division by zero:
1025 ///
1026 /// ```should_panic
1027 /// #![feature(strict_overflow_ops)]
1028 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
1029 /// ```
1030 ///
1031 /// The following panics because of overflow:
1032 ///
1033 /// ```should_panic
1034 /// #![feature(strict_overflow_ops)]
1035 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem(-1);")]
1036 /// ```
1037 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
1038 #[must_use = "this returns the result of the operation, \
1039 without modifying the original"]
1040 #[inline]
1041 #[track_caller]
1042 pub const fn strict_rem(self, rhs: Self) -> Self {
1043 let (a, b) = self.overflowing_rem(rhs);
1044 if b { overflow_panic::rem() } else { a }
1045 }
1046
1047 /// Checked Euclidean remainder. Computes `self.rem_euclid(rhs)`, returning `None`
1048 /// if `rhs == 0` or the division results in overflow.
1049 ///
1050 /// # Examples
1051 ///
1052 /// Basic usage:
1053 ///
1054 /// ```
1055 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
1056 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
1057 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_rem_euclid(-1), None);")]
1058 /// ```
1059 #[stable(feature = "euclidean_division", since = "1.38.0")]
1060 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1061 #[must_use = "this returns the result of the operation, \
1062 without modifying the original"]
1063 #[inline]
1064 pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
1065 // Using `&` helps LLVM see that it is the same check made in division.
1066 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
1067 None
1068 } else {
1069 Some(self.rem_euclid(rhs))
1070 }
1071 }
1072
1073 /// Strict Euclidean remainder. Computes `self.rem_euclid(rhs)`, panicking if
1074 /// the division results in overflow.
1075 ///
1076 /// # Panics
1077 ///
1078 /// This function will panic if `rhs` is zero.
1079 ///
1080 /// ## Overflow behavior
1081 ///
1082 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1083 ///
1084 /// The only case where such an overflow can occur is `x % y` for `MIN / -1` on a
1085 /// signed type (where `MIN` is the negative minimal value), which is invalid due to implementation artifacts.
1086 ///
1087 /// # Examples
1088 ///
1089 /// Basic usage:
1090 ///
1091 /// ```
1092 /// #![feature(strict_overflow_ops)]
1093 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_rem_euclid(2), 1);")]
1094 /// ```
1095 ///
1096 /// The following panics because of division by zero:
1097 ///
1098 /// ```should_panic
1099 /// #![feature(strict_overflow_ops)]
1100 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
1101 /// ```
1102 ///
1103 /// The following panics because of overflow:
1104 ///
1105 /// ```should_panic
1106 /// #![feature(strict_overflow_ops)]
1107 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem_euclid(-1);")]
1108 /// ```
1109 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
1110 #[must_use = "this returns the result of the operation, \
1111 without modifying the original"]
1112 #[inline]
1113 #[track_caller]
1114 pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
1115 let (a, b) = self.overflowing_rem_euclid(rhs);
1116 if b { overflow_panic::rem() } else { a }
1117 }
1118
1119 /// Checked negation. Computes `-self`, returning `None` if `self == MIN`.
1120 ///
1121 /// # Examples
1122 ///
1123 /// Basic usage:
1124 ///
1125 /// ```
1126 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_neg(), Some(-5));")]
1127 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_neg(), None);")]
1128 /// ```
1129 #[stable(feature = "wrapping", since = "1.7.0")]
1130 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1131 #[must_use = "this returns the result of the operation, \
1132 without modifying the original"]
1133 #[inline]
1134 pub const fn checked_neg(self) -> Option<Self> {
1135 let (a, b) = self.overflowing_neg();
1136 if intrinsics::unlikely(b) { None } else { Some(a) }
1137 }
1138
1139 /// Unchecked negation. Computes `-self`, assuming overflow cannot occur.
1140 ///
1141 /// # Safety
1142 ///
1143 /// This results in undefined behavior when
1144 #[doc = concat!("`self == ", stringify!($SelfT), "::MIN`,")]
1145 /// i.e. when [`checked_neg`] would return `None`.
1146 ///
1147 #[doc = concat!("[`checked_neg`]: ", stringify!($SelfT), "::checked_neg")]
1148 #[unstable(
1149 feature = "unchecked_neg",
1150 reason = "niche optimization path",
1151 issue = "85122",
1152 )]
1153 #[must_use = "this returns the result of the operation, \
1154 without modifying the original"]
1155 #[inline(always)]
1156 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
1157 pub const unsafe fn unchecked_neg(self) -> Self {
1158 assert_unsafe_precondition!(
1159 check_language_ub,
1160 concat!(stringify!($SelfT), "::unchecked_neg cannot overflow"),
1161 (
1162 lhs: $SelfT = self,
1163 ) => !lhs.overflowing_neg().1,
1164 );
1165
1166 // SAFETY: this is guaranteed to be safe by the caller.
1167 unsafe {
1168 intrinsics::unchecked_sub(0, self)
1169 }
1170 }
1171
1172 /// Strict negation. Computes `-self`, panicking if `self == MIN`.
1173 ///
1174 /// # Panics
1175 ///
1176 /// ## Overflow behavior
1177 ///
1178 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1179 ///
1180 /// # Examples
1181 ///
1182 /// Basic usage:
1183 ///
1184 /// ```
1185 /// #![feature(strict_overflow_ops)]
1186 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_neg(), -5);")]
1187 /// ```
1188 ///
1189 /// The following panics because of overflow:
1190 ///
1191 /// ```should_panic
1192 /// #![feature(strict_overflow_ops)]
1193 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_neg();")]
1194 ///
1195 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
1196 #[must_use = "this returns the result of the operation, \
1197 without modifying the original"]
1198 #[inline]
1199 #[track_caller]
1200 pub const fn strict_neg(self) -> Self {
1201 let (a, b) = self.overflowing_neg();
1202 if b { overflow_panic::neg() } else { a }
1203 }
1204
1205 /// Checked shift left. Computes `self << rhs`, returning `None` if `rhs` is larger
1206 /// than or equal to the number of bits in `self`.
1207 ///
1208 /// # Examples
1209 ///
1210 /// Basic usage:
1211 ///
1212 /// ```
1213 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
1214 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(129), None);")]
1215 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
1216 /// ```
1217 #[stable(feature = "wrapping", since = "1.7.0")]
1218 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1219 #[must_use = "this returns the result of the operation, \
1220 without modifying the original"]
1221 #[inline]
1222 pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
1223 // Not using overflowing_shl as that's a wrapping shift
1224 if rhs < Self::BITS {
1225 // SAFETY: just checked the RHS is in-range
1226 Some(unsafe { self.unchecked_shl(rhs) })
1227 } else {
1228 None
1229 }
1230 }
1231
1232 /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
1233 /// than or equal to the number of bits in `self`.
1234 ///
1235 /// # Panics
1236 ///
1237 /// ## Overflow behavior
1238 ///
1239 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1240 ///
1241 /// # Examples
1242 ///
1243 /// Basic usage:
1244 ///
1245 /// ```
1246 /// #![feature(strict_overflow_ops)]
1247 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
1248 /// ```
1249 ///
1250 /// The following panics because of overflow:
1251 ///
1252 /// ```should_panic
1253 /// #![feature(strict_overflow_ops)]
1254 #[doc = concat!("let _ = 0x1", stringify!($SelfT), ".strict_shl(129);")]
1255 /// ```
1256 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
1257 #[must_use = "this returns the result of the operation, \
1258 without modifying the original"]
1259 #[inline]
1260 #[track_caller]
1261 pub const fn strict_shl(self, rhs: u32) -> Self {
1262 let (a, b) = self.overflowing_shl(rhs);
1263 if b { overflow_panic::shl() } else { a }
1264 }
1265
1266 /// Unchecked shift left. Computes `self << rhs`, assuming that
1267 /// `rhs` is less than the number of bits in `self`.
1268 ///
1269 /// # Safety
1270 ///
1271 /// This results in undefined behavior if `rhs` is larger than
1272 /// or equal to the number of bits in `self`,
1273 /// i.e. when [`checked_shl`] would return `None`.
1274 ///
1275 #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
1276 #[unstable(
1277 feature = "unchecked_shifts",
1278 reason = "niche optimization path",
1279 issue = "85122",
1280 )]
1281 #[must_use = "this returns the result of the operation, \
1282 without modifying the original"]
1283 #[inline(always)]
1284 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
1285 pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
1286 assert_unsafe_precondition!(
1287 check_language_ub,
1288 concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
1289 (
1290 rhs: u32 = rhs,
1291 ) => rhs < <$ActualT>::BITS,
1292 );
1293
1294 // SAFETY: this is guaranteed to be safe by the caller.
1295 unsafe {
1296 intrinsics::unchecked_shl(self, rhs)
1297 }
1298 }
1299
1300 /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`.
1301 ///
1302 /// If `rhs` is larger or equal to the number of bits in `self`,
1303 /// the entire value is shifted out, and `0` is returned.
1304 ///
1305 /// # Examples
1306 ///
1307 /// Basic usage:
1308 /// ```
1309 /// #![feature(unbounded_shifts)]
1310 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
1311 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(129), 0);")]
1312 /// ```
1313 #[unstable(feature = "unbounded_shifts", issue = "129375")]
1314 #[must_use = "this returns the result of the operation, \
1315 without modifying the original"]
1316 #[inline]
1317 pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
1318 if rhs < Self::BITS {
1319 // SAFETY:
1320 // rhs is just checked to be in-range above
1321 unsafe { self.unchecked_shl(rhs) }
1322 } else {
1323 0
1324 }
1325 }
1326
1327 /// Checked shift right. Computes `self >> rhs`, returning `None` if `rhs` is
1328 /// larger than or equal to the number of bits in `self`.
1329 ///
1330 /// # Examples
1331 ///
1332 /// Basic usage:
1333 ///
1334 /// ```
1335 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
1336 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(128), None);")]
1337 /// ```
1338 #[stable(feature = "wrapping", since = "1.7.0")]
1339 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1340 #[must_use = "this returns the result of the operation, \
1341 without modifying the original"]
1342 #[inline]
1343 pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
1344 // Not using overflowing_shr as that's a wrapping shift
1345 if rhs < Self::BITS {
1346 // SAFETY: just checked the RHS is in-range
1347 Some(unsafe { self.unchecked_shr(rhs) })
1348 } else {
1349 None
1350 }
1351 }
1352
1353 /// Strict shift right. Computes `self >> rhs`, panicking `rhs` is
1354 /// larger than or equal to the number of bits in `self`.
1355 ///
1356 /// # Panics
1357 ///
1358 /// ## Overflow behavior
1359 ///
1360 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1361 ///
1362 /// # Examples
1363 ///
1364 /// Basic usage:
1365 ///
1366 /// ```
1367 /// #![feature(strict_overflow_ops)]
1368 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
1369 /// ```
1370 ///
1371 /// The following panics because of overflow:
1372 ///
1373 /// ```should_panic
1374 /// #![feature(strict_overflow_ops)]
1375 #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(128);")]
1376 /// ```
1377 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
1378 #[must_use = "this returns the result of the operation, \
1379 without modifying the original"]
1380 #[inline]
1381 #[track_caller]
1382 pub const fn strict_shr(self, rhs: u32) -> Self {
1383 let (a, b) = self.overflowing_shr(rhs);
1384 if b { overflow_panic::shr() } else { a }
1385 }
1386
1387 /// Unchecked shift right. Computes `self >> rhs`, assuming that
1388 /// `rhs` is less than the number of bits in `self`.
1389 ///
1390 /// # Safety
1391 ///
1392 /// This results in undefined behavior if `rhs` is larger than
1393 /// or equal to the number of bits in `self`,
1394 /// i.e. when [`checked_shr`] would return `None`.
1395 ///
1396 #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
1397 #[unstable(
1398 feature = "unchecked_shifts",
1399 reason = "niche optimization path",
1400 issue = "85122",
1401 )]
1402 #[must_use = "this returns the result of the operation, \
1403 without modifying the original"]
1404 #[inline(always)]
1405 #[cfg_attr(miri, track_caller)] // even without panics, this helps for Miri backtraces
1406 pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
1407 assert_unsafe_precondition!(
1408 check_language_ub,
1409 concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
1410 (
1411 rhs: u32 = rhs,
1412 ) => rhs < <$ActualT>::BITS,
1413 );
1414
1415 // SAFETY: this is guaranteed to be safe by the caller.
1416 unsafe {
1417 intrinsics::unchecked_shr(self, rhs)
1418 }
1419 }
1420
1421 /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`.
1422 ///
1423 /// If `rhs` is larger or equal to the number of bits in `self`,
1424 /// the entire value is shifted out, which yields `0` for a positive number,
1425 /// and `-1` for a negative number.
1426 ///
1427 /// # Examples
1428 ///
1429 /// Basic usage:
1430 /// ```
1431 /// #![feature(unbounded_shifts)]
1432 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
1433 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(129), 0);")]
1434 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.unbounded_shr(129), -1);")]
1435 /// ```
1436 #[unstable(feature = "unbounded_shifts", issue = "129375")]
1437 #[must_use = "this returns the result of the operation, \
1438 without modifying the original"]
1439 #[inline]
1440 pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
1441 if rhs < Self::BITS {
1442 // SAFETY:
1443 // rhs is just checked to be in-range above
1444 unsafe { self.unchecked_shr(rhs) }
1445 } else {
1446 // A shift by `Self::BITS-1` suffices for signed integers, because the sign bit is copied for each of the shifted bits.
1447
1448 // SAFETY:
1449 // `Self::BITS-1` is guaranteed to be less than `Self::BITS`
1450 unsafe { self.unchecked_shr(Self::BITS - 1) }
1451 }
1452 }
1453
1454 /// Checked absolute value. Computes `self.abs()`, returning `None` if
1455 /// `self == MIN`.
1456 ///
1457 /// # Examples
1458 ///
1459 /// Basic usage:
1460 ///
1461 /// ```
1462 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").checked_abs(), Some(5));")]
1463 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_abs(), None);")]
1464 /// ```
1465 #[stable(feature = "no_panic_abs", since = "1.13.0")]
1466 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1467 #[must_use = "this returns the result of the operation, \
1468 without modifying the original"]
1469 #[inline]
1470 pub const fn checked_abs(self) -> Option<Self> {
1471 if self.is_negative() {
1472 self.checked_neg()
1473 } else {
1474 Some(self)
1475 }
1476 }
1477
1478 /// Strict absolute value. Computes `self.abs()`, panicking if
1479 /// `self == MIN`.
1480 ///
1481 /// # Panics
1482 ///
1483 /// ## Overflow behavior
1484 ///
1485 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1486 ///
1487 /// # Examples
1488 ///
1489 /// Basic usage:
1490 ///
1491 /// ```
1492 /// #![feature(strict_overflow_ops)]
1493 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").strict_abs(), 5);")]
1494 /// ```
1495 ///
1496 /// The following panics because of overflow:
1497 ///
1498 /// ```should_panic
1499 /// #![feature(strict_overflow_ops)]
1500 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_abs();")]
1501 /// ```
1502 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
1503 #[must_use = "this returns the result of the operation, \
1504 without modifying the original"]
1505 #[inline]
1506 #[track_caller]
1507 pub const fn strict_abs(self) -> Self {
1508 if self.is_negative() {
1509 self.strict_neg()
1510 } else {
1511 self
1512 }
1513 }
1514
1515 /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
1516 /// overflow occurred.
1517 ///
1518 /// # Examples
1519 ///
1520 /// Basic usage:
1521 ///
1522 /// ```
1523 #[doc = concat!("assert_eq!(8", stringify!($SelfT), ".checked_pow(2), Some(64));")]
1524 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
1525 /// ```
1526
1527 #[stable(feature = "no_panic_pow", since = "1.34.0")]
1528 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
1529 #[must_use = "this returns the result of the operation, \
1530 without modifying the original"]
1531 #[inline]
1532 pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
1533 if exp == 0 {
1534 return Some(1);
1535 }
1536 let mut base = self;
1537 let mut acc: Self = 1;
1538
1539 loop {
1540 if (exp & 1) == 1 {
1541 acc = try_opt!(acc.checked_mul(base));
1542 // since exp!=0, finally the exp must be 1.
1543 if exp == 1 {
1544 return Some(acc);
1545 }
1546 }
1547 exp /= 2;
1548 base = try_opt!(base.checked_mul(base));
1549 }
1550 }
1551
1552 /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
1553 /// overflow occurred.
1554 ///
1555 /// # Panics
1556 ///
1557 /// ## Overflow behavior
1558 ///
1559 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1560 ///
1561 /// # Examples
1562 ///
1563 /// Basic usage:
1564 ///
1565 /// ```
1566 /// #![feature(strict_overflow_ops)]
1567 #[doc = concat!("assert_eq!(8", stringify!($SelfT), ".strict_pow(2), 64);")]
1568 /// ```
1569 ///
1570 /// The following panics because of overflow:
1571 ///
1572 /// ```should_panic
1573 /// #![feature(strict_overflow_ops)]
1574 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
1575 /// ```
1576 #[unstable(feature = "strict_overflow_ops", issue = "118260")]
1577 #[must_use = "this returns the result of the operation, \
1578 without modifying the original"]
1579 #[inline]
1580 #[track_caller]
1581 pub const fn strict_pow(self, mut exp: u32) -> Self {
1582 if exp == 0 {
1583 return 1;
1584 }
1585 let mut base = self;
1586 let mut acc: Self = 1;
1587
1588 loop {
1589 if (exp & 1) == 1 {
1590 acc = acc.strict_mul(base);
1591 // since exp!=0, finally the exp must be 1.
1592 if exp == 1 {
1593 return acc;
1594 }
1595 }
1596 exp /= 2;
1597 base = base.strict_mul(base);
1598 }
1599 }
1600
1601 /// Returns the square root of the number, rounded down.
1602 ///
1603 /// Returns `None` if `self` is negative.
1604 ///
1605 /// # Examples
1606 ///
1607 /// Basic usage:
1608 /// ```
1609 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_isqrt(), Some(3));")]
1610 /// ```
1611 #[stable(feature = "isqrt", since = "1.84.0")]
1612 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
1613 #[must_use = "this returns the result of the operation, \
1614 without modifying the original"]
1615 #[inline]
1616 pub const fn checked_isqrt(self) -> Option<Self> {
1617 if self < 0 {
1618 None
1619 } else {
1620 // SAFETY: Input is nonnegative in this `else` branch.
1621 let result = unsafe {
1622 crate::num::int_sqrt::$ActualT(self as $ActualT) as $SelfT
1623 };
1624
1625 // Inform the optimizer what the range of outputs is. If
1626 // testing `core` crashes with no panic message and a
1627 // `num::int_sqrt::i*` test failed, it's because your edits
1628 // caused these assertions to become false.
1629 //
1630 // SAFETY: Integer square root is a monotonically nondecreasing
1631 // function, which means that increasing the input will never
1632 // cause the output to decrease. Thus, since the input for
1633 // nonnegative signed integers is bounded by
1634 // `[0, <$ActualT>::MAX]`, sqrt(n) will be bounded by
1635 // `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
1636 unsafe {
1637 // SAFETY: `<$ActualT>::MAX` is nonnegative.
1638 const MAX_RESULT: $SelfT = unsafe {
1639 crate::num::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT
1640 };
1641
1642 crate::hint::assert_unchecked(result >= 0);
1643 crate::hint::assert_unchecked(result <= MAX_RESULT);
1644 }
1645
1646 Some(result)
1647 }
1648 }
1649
1650 /// Saturating integer addition. Computes `self + rhs`, saturating at the numeric
1651 /// bounds instead of overflowing.
1652 ///
1653 /// # Examples
1654 ///
1655 /// Basic usage:
1656 ///
1657 /// ```
1658 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
1659 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(100), ", stringify!($SelfT), "::MAX);")]
1660 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_add(-1), ", stringify!($SelfT), "::MIN);")]
1661 /// ```
1662
1663 #[stable(feature = "rust1", since = "1.0.0")]
1664 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1665 #[must_use = "this returns the result of the operation, \
1666 without modifying the original"]
1667 #[inline(always)]
1668 pub const fn saturating_add(self, rhs: Self) -> Self {
1669 intrinsics::saturating_add(self, rhs)
1670 }
1671
1672 /// Saturating addition with an unsigned integer. Computes `self + rhs`,
1673 /// saturating at the numeric bounds instead of overflowing.
1674 ///
1675 /// # Examples
1676 ///
1677 /// Basic usage:
1678 ///
1679 /// ```
1680 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_unsigned(2), 3);")]
1681 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add_unsigned(100), ", stringify!($SelfT), "::MAX);")]
1682 /// ```
1683 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1684 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1685 #[must_use = "this returns the result of the operation, \
1686 without modifying the original"]
1687 #[inline]
1688 pub const fn saturating_add_unsigned(self, rhs: $UnsignedT) -> Self {
1689 // Overflow can only happen at the upper bound
1690 // We cannot use `unwrap_or` here because it is not `const`
1691 match self.checked_add_unsigned(rhs) {
1692 Some(x) => x,
1693 None => Self::MAX,
1694 }
1695 }
1696
1697 /// Saturating integer subtraction. Computes `self - rhs`, saturating at the
1698 /// numeric bounds instead of overflowing.
1699 ///
1700 /// # Examples
1701 ///
1702 /// Basic usage:
1703 ///
1704 /// ```
1705 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(127), -27);")]
1706 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub(100), ", stringify!($SelfT), "::MIN);")]
1707 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_sub(-1), ", stringify!($SelfT), "::MAX);")]
1708 /// ```
1709 #[stable(feature = "rust1", since = "1.0.0")]
1710 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1711 #[must_use = "this returns the result of the operation, \
1712 without modifying the original"]
1713 #[inline(always)]
1714 pub const fn saturating_sub(self, rhs: Self) -> Self {
1715 intrinsics::saturating_sub(self, rhs)
1716 }
1717
1718 /// Saturating subtraction with an unsigned integer. Computes `self - rhs`,
1719 /// saturating at the numeric bounds instead of overflowing.
1720 ///
1721 /// # Examples
1722 ///
1723 /// Basic usage:
1724 ///
1725 /// ```
1726 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub_unsigned(127), -27);")]
1727 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub_unsigned(100), ", stringify!($SelfT), "::MIN);")]
1728 /// ```
1729 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1730 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1731 #[must_use = "this returns the result of the operation, \
1732 without modifying the original"]
1733 #[inline]
1734 pub const fn saturating_sub_unsigned(self, rhs: $UnsignedT) -> Self {
1735 // Overflow can only happen at the lower bound
1736 // We cannot use `unwrap_or` here because it is not `const`
1737 match self.checked_sub_unsigned(rhs) {
1738 Some(x) => x,
1739 None => Self::MIN,
1740 }
1741 }
1742
1743 /// Saturating integer negation. Computes `-self`, returning `MAX` if `self == MIN`
1744 /// instead of overflowing.
1745 ///
1746 /// # Examples
1747 ///
1748 /// Basic usage:
1749 ///
1750 /// ```
1751 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_neg(), -100);")]
1752 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").saturating_neg(), 100);")]
1753 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_neg(), ", stringify!($SelfT), "::MAX);")]
1754 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_neg(), ", stringify!($SelfT), "::MIN + 1);")]
1755 /// ```
1756
1757 #[stable(feature = "saturating_neg", since = "1.45.0")]
1758 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1759 #[must_use = "this returns the result of the operation, \
1760 without modifying the original"]
1761 #[inline(always)]
1762 pub const fn saturating_neg(self) -> Self {
1763 intrinsics::saturating_sub(0, self)
1764 }
1765
1766 /// Saturating absolute value. Computes `self.abs()`, returning `MAX` if `self ==
1767 /// MIN` instead of overflowing.
1768 ///
1769 /// # Examples
1770 ///
1771 /// Basic usage:
1772 ///
1773 /// ```
1774 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_abs(), 100);")]
1775 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").saturating_abs(), 100);")]
1776 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_abs(), ", stringify!($SelfT), "::MAX);")]
1777 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).saturating_abs(), ", stringify!($SelfT), "::MAX);")]
1778 /// ```
1779
1780 #[stable(feature = "saturating_neg", since = "1.45.0")]
1781 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1782 #[must_use = "this returns the result of the operation, \
1783 without modifying the original"]
1784 #[inline]
1785 pub const fn saturating_abs(self) -> Self {
1786 if self.is_negative() {
1787 self.saturating_neg()
1788 } else {
1789 self
1790 }
1791 }
1792
1793 /// Saturating integer multiplication. Computes `self * rhs`, saturating at the
1794 /// numeric bounds instead of overflowing.
1795 ///
1796 /// # Examples
1797 ///
1798 /// Basic usage:
1799 ///
1800 /// ```
1801 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".saturating_mul(12), 120);")]
1802 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_mul(10), ", stringify!($SelfT), "::MAX);")]
1803 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_mul(10), ", stringify!($SelfT), "::MIN);")]
1804 /// ```
1805 #[stable(feature = "wrapping", since = "1.7.0")]
1806 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1807 #[must_use = "this returns the result of the operation, \
1808 without modifying the original"]
1809 #[inline]
1810 pub const fn saturating_mul(self, rhs: Self) -> Self {
1811 match self.checked_mul(rhs) {
1812 Some(x) => x,
1813 None => if (self < 0) == (rhs < 0) {
1814 Self::MAX
1815 } else {
1816 Self::MIN
1817 }
1818 }
1819 }
1820
1821 /// Saturating integer division. Computes `self / rhs`, saturating at the
1822 /// numeric bounds instead of overflowing.
1823 ///
1824 /// # Panics
1825 ///
1826 /// This function will panic if `rhs` is zero.
1827 ///
1828 /// # Examples
1829 ///
1830 /// Basic usage:
1831 ///
1832 /// ```
1833 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
1834 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_div(-1), ", stringify!($SelfT), "::MIN + 1);")]
1835 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_div(-1), ", stringify!($SelfT), "::MAX);")]
1836 ///
1837 /// ```
1838 #[stable(feature = "saturating_div", since = "1.58.0")]
1839 #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
1840 #[must_use = "this returns the result of the operation, \
1841 without modifying the original"]
1842 #[inline]
1843 pub const fn saturating_div(self, rhs: Self) -> Self {
1844 match self.overflowing_div(rhs) {
1845 (result, false) => result,
1846 (_result, true) => Self::MAX, // MIN / -1 is the only possible saturating overflow
1847 }
1848 }
1849
1850 /// Saturating integer exponentiation. Computes `self.pow(exp)`,
1851 /// saturating at the numeric bounds instead of overflowing.
1852 ///
1853 /// # Examples
1854 ///
1855 /// Basic usage:
1856 ///
1857 /// ```
1858 #[doc = concat!("assert_eq!((-4", stringify!($SelfT), ").saturating_pow(3), -64);")]
1859 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
1860 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(3), ", stringify!($SelfT), "::MIN);")]
1861 /// ```
1862 #[stable(feature = "no_panic_pow", since = "1.34.0")]
1863 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
1864 #[must_use = "this returns the result of the operation, \
1865 without modifying the original"]
1866 #[inline]
1867 pub const fn saturating_pow(self, exp: u32) -> Self {
1868 match self.checked_pow(exp) {
1869 Some(x) => x,
1870 None if self < 0 && exp % 2 == 1 => Self::MIN,
1871 None => Self::MAX,
1872 }
1873 }
1874
1875 /// Wrapping (modular) addition. Computes `self + rhs`, wrapping around at the
1876 /// boundary of the type.
1877 ///
1878 /// # Examples
1879 ///
1880 /// Basic usage:
1881 ///
1882 /// ```
1883 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add(27), 127);")]
1884 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add(2), ", stringify!($SelfT), "::MIN + 1);")]
1885 /// ```
1886 #[stable(feature = "rust1", since = "1.0.0")]
1887 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
1888 #[must_use = "this returns the result of the operation, \
1889 without modifying the original"]
1890 #[inline(always)]
1891 pub const fn wrapping_add(self, rhs: Self) -> Self {
1892 intrinsics::wrapping_add(self, rhs)
1893 }
1894
1895 /// Wrapping (modular) addition with an unsigned integer. Computes
1896 /// `self + rhs`, wrapping around at the boundary of the type.
1897 ///
1898 /// # Examples
1899 ///
1900 /// Basic usage:
1901 ///
1902 /// ```
1903 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add_unsigned(27), 127);")]
1904 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add_unsigned(2), ", stringify!($SelfT), "::MIN + 1);")]
1905 /// ```
1906 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1907 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1908 #[must_use = "this returns the result of the operation, \
1909 without modifying the original"]
1910 #[inline(always)]
1911 pub const fn wrapping_add_unsigned(self, rhs: $UnsignedT) -> Self {
1912 self.wrapping_add(rhs as Self)
1913 }
1914
1915 /// Wrapping (modular) subtraction. Computes `self - rhs`, wrapping around at the
1916 /// boundary of the type.
1917 ///
1918 /// # Examples
1919 ///
1920 /// Basic usage:
1921 ///
1922 /// ```
1923 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub(127), -127);")]
1924 #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub(", stringify!($SelfT), "::MAX), ", stringify!($SelfT), "::MAX);")]
1925 /// ```
1926 #[stable(feature = "rust1", since = "1.0.0")]
1927 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
1928 #[must_use = "this returns the result of the operation, \
1929 without modifying the original"]
1930 #[inline(always)]
1931 pub const fn wrapping_sub(self, rhs: Self) -> Self {
1932 intrinsics::wrapping_sub(self, rhs)
1933 }
1934
1935 /// Wrapping (modular) subtraction with an unsigned integer. Computes
1936 /// `self - rhs`, wrapping around at the boundary of the type.
1937 ///
1938 /// # Examples
1939 ///
1940 /// Basic usage:
1941 ///
1942 /// ```
1943 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub_unsigned(127), -127);")]
1944 #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub_unsigned(", stringify!($UnsignedT), "::MAX), -1);")]
1945 /// ```
1946 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1947 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1948 #[must_use = "this returns the result of the operation, \
1949 without modifying the original"]
1950 #[inline(always)]
1951 pub const fn wrapping_sub_unsigned(self, rhs: $UnsignedT) -> Self {
1952 self.wrapping_sub(rhs as Self)
1953 }
1954
1955 /// Wrapping (modular) multiplication. Computes `self * rhs`, wrapping around at
1956 /// the boundary of the type.
1957 ///
1958 /// # Examples
1959 ///
1960 /// Basic usage:
1961 ///
1962 /// ```
1963 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".wrapping_mul(12), 120);")]
1964 /// assert_eq!(11i8.wrapping_mul(12), -124);
1965 /// ```
1966 #[stable(feature = "rust1", since = "1.0.0")]
1967 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
1968 #[must_use = "this returns the result of the operation, \
1969 without modifying the original"]
1970 #[inline(always)]
1971 pub const fn wrapping_mul(self, rhs: Self) -> Self {
1972 intrinsics::wrapping_mul(self, rhs)
1973 }
1974
1975 /// Wrapping (modular) division. Computes `self / rhs`, wrapping around at the
1976 /// boundary of the type.
1977 ///
1978 /// The only case where such wrapping can occur is when one divides `MIN / -1` on a signed type (where
1979 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
1980 /// that is too large to represent in the type. In such a case, this function returns `MIN` itself.
1981 ///
1982 /// # Panics
1983 ///
1984 /// This function will panic if `rhs` is zero.
1985 ///
1986 /// # Examples
1987 ///
1988 /// Basic usage:
1989 ///
1990 /// ```
1991 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
1992 /// assert_eq!((-128i8).wrapping_div(-1), -128);
1993 /// ```
1994 #[stable(feature = "num_wrapping", since = "1.2.0")]
1995 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
1996 #[must_use = "this returns the result of the operation, \
1997 without modifying the original"]
1998 #[inline]
1999 pub const fn wrapping_div(self, rhs: Self) -> Self {
2000 self.overflowing_div(rhs).0
2001 }
2002
2003 /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`,
2004 /// wrapping around at the boundary of the type.
2005 ///
2006 /// Wrapping will only occur in `MIN / -1` on a signed type (where `MIN` is the negative minimal value
2007 /// for the type). This is equivalent to `-MIN`, a positive value that is too large to represent in the
2008 /// type. In this case, this method returns `MIN` itself.
2009 ///
2010 /// # Panics
2011 ///
2012 /// This function will panic if `rhs` is zero.
2013 ///
2014 /// # Examples
2015 ///
2016 /// Basic usage:
2017 ///
2018 /// ```
2019 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
2020 /// assert_eq!((-128i8).wrapping_div_euclid(-1), -128);
2021 /// ```
2022 #[stable(feature = "euclidean_division", since = "1.38.0")]
2023 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2024 #[must_use = "this returns the result of the operation, \
2025 without modifying the original"]
2026 #[inline]
2027 pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
2028 self.overflowing_div_euclid(rhs).0
2029 }
2030
2031 /// Wrapping (modular) remainder. Computes `self % rhs`, wrapping around at the
2032 /// boundary of the type.
2033 ///
2034 /// Such wrap-around never actually occurs mathematically; implementation artifacts make `x % y`
2035 /// invalid for `MIN / -1` on a signed type (where `MIN` is the negative minimal value). In such a case,
2036 /// this function returns `0`.
2037 ///
2038 /// # Panics
2039 ///
2040 /// This function will panic if `rhs` is zero.
2041 ///
2042 /// # Examples
2043 ///
2044 /// Basic usage:
2045 ///
2046 /// ```
2047 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
2048 /// assert_eq!((-128i8).wrapping_rem(-1), 0);
2049 /// ```
2050 #[stable(feature = "num_wrapping", since = "1.2.0")]
2051 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2052 #[must_use = "this returns the result of the operation, \
2053 without modifying the original"]
2054 #[inline]
2055 pub const fn wrapping_rem(self, rhs: Self) -> Self {
2056 self.overflowing_rem(rhs).0
2057 }
2058
2059 /// Wrapping Euclidean remainder. Computes `self.rem_euclid(rhs)`, wrapping around
2060 /// at the boundary of the type.
2061 ///
2062 /// Wrapping will only occur in `MIN % -1` on a signed type (where `MIN` is the negative minimal value
2063 /// for the type). In this case, this method returns 0.
2064 ///
2065 /// # Panics
2066 ///
2067 /// This function will panic if `rhs` is zero.
2068 ///
2069 /// # Examples
2070 ///
2071 /// Basic usage:
2072 ///
2073 /// ```
2074 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
2075 /// assert_eq!((-128i8).wrapping_rem_euclid(-1), 0);
2076 /// ```
2077 #[stable(feature = "euclidean_division", since = "1.38.0")]
2078 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2079 #[must_use = "this returns the result of the operation, \
2080 without modifying the original"]
2081 #[inline]
2082 pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
2083 self.overflowing_rem_euclid(rhs).0
2084 }
2085
2086 /// Wrapping (modular) negation. Computes `-self`, wrapping around at the boundary
2087 /// of the type.
2088 ///
2089 /// The only case where such wrapping can occur is when one negates `MIN` on a signed type (where `MIN`
2090 /// is the negative minimal value for the type); this is a positive value that is too large to represent
2091 /// in the type. In such a case, this function returns `MIN` itself.
2092 ///
2093 /// # Examples
2094 ///
2095 /// Basic usage:
2096 ///
2097 /// ```
2098 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_neg(), -100);")]
2099 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").wrapping_neg(), 100);")]
2100 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.wrapping_neg(), ", stringify!($SelfT), "::MIN);")]
2101 /// ```
2102 #[stable(feature = "num_wrapping", since = "1.2.0")]
2103 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2104 #[must_use = "this returns the result of the operation, \
2105 without modifying the original"]
2106 #[inline(always)]
2107 pub const fn wrapping_neg(self) -> Self {
2108 (0 as $SelfT).wrapping_sub(self)
2109 }
2110
2111 /// Panic-free bitwise shift-left; yields `self << mask(rhs)`, where `mask` removes
2112 /// any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type.
2113 ///
2114 /// Note that this is *not* the same as a rotate-left; the RHS of a wrapping shift-left is restricted to
2115 /// the range of the type, rather than the bits shifted out of the LHS being returned to the other end.
2116 /// The primitive integer types all implement a [`rotate_left`](Self::rotate_left) function,
2117 /// which may be what you want instead.
2118 ///
2119 /// # Examples
2120 ///
2121 /// Basic usage:
2122 ///
2123 /// ```
2124 #[doc = concat!("assert_eq!((-1", stringify!($SelfT), ").wrapping_shl(7), -128);")]
2125 #[doc = concat!("assert_eq!((-1", stringify!($SelfT), ").wrapping_shl(128), -1);")]
2126 /// ```
2127 #[stable(feature = "num_wrapping", since = "1.2.0")]
2128 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2129 #[must_use = "this returns the result of the operation, \
2130 without modifying the original"]
2131 #[inline(always)]
2132 pub const fn wrapping_shl(self, rhs: u32) -> Self {
2133 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2134 // out of bounds
2135 unsafe {
2136 self.unchecked_shl(rhs & (Self::BITS - 1))
2137 }
2138 }
2139
2140 /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`, where `mask`
2141 /// removes any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type.
2142 ///
2143 /// Note that this is *not* the same as a rotate-right; the RHS of a wrapping shift-right is restricted
2144 /// to the range of the type, rather than the bits shifted out of the LHS being returned to the other
2145 /// end. The primitive integer types all implement a [`rotate_right`](Self::rotate_right) function,
2146 /// which may be what you want instead.
2147 ///
2148 /// # Examples
2149 ///
2150 /// Basic usage:
2151 ///
2152 /// ```
2153 #[doc = concat!("assert_eq!((-128", stringify!($SelfT), ").wrapping_shr(7), -1);")]
2154 /// assert_eq!((-128i16).wrapping_shr(64), -128);
2155 /// ```
2156 #[stable(feature = "num_wrapping", since = "1.2.0")]
2157 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2158 #[must_use = "this returns the result of the operation, \
2159 without modifying the original"]
2160 #[inline(always)]
2161 pub const fn wrapping_shr(self, rhs: u32) -> Self {
2162 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2163 // out of bounds
2164 unsafe {
2165 self.unchecked_shr(rhs & (Self::BITS - 1))
2166 }
2167 }
2168
2169 /// Wrapping (modular) absolute value. Computes `self.abs()`, wrapping around at
2170 /// the boundary of the type.
2171 ///
2172 /// The only case where such wrapping can occur is when one takes the absolute value of the negative
2173 /// minimal value for the type; this is a positive value that is too large to represent in the type. In
2174 /// such a case, this function returns `MIN` itself.
2175 ///
2176 /// # Examples
2177 ///
2178 /// Basic usage:
2179 ///
2180 /// ```
2181 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_abs(), 100);")]
2182 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").wrapping_abs(), 100);")]
2183 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.wrapping_abs(), ", stringify!($SelfT), "::MIN);")]
2184 /// assert_eq!((-128i8).wrapping_abs() as u8, 128);
2185 /// ```
2186 #[stable(feature = "no_panic_abs", since = "1.13.0")]
2187 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2188 #[must_use = "this returns the result of the operation, \
2189 without modifying the original"]
2190 #[allow(unused_attributes)]
2191 #[inline]
2192 pub const fn wrapping_abs(self) -> Self {
2193 if self.is_negative() {
2194 self.wrapping_neg()
2195 } else {
2196 self
2197 }
2198 }
2199
2200 /// Computes the absolute value of `self` without any wrapping
2201 /// or panicking.
2202 ///
2203 ///
2204 /// # Examples
2205 ///
2206 /// Basic usage:
2207 ///
2208 /// ```
2209 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".unsigned_abs(), 100", stringify!($UnsignedT), ");")]
2210 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").unsigned_abs(), 100", stringify!($UnsignedT), ");")]
2211 /// assert_eq!((-128i8).unsigned_abs(), 128u8);
2212 /// ```
2213 #[stable(feature = "unsigned_abs", since = "1.51.0")]
2214 #[rustc_const_stable(feature = "unsigned_abs", since = "1.51.0")]
2215 #[must_use = "this returns the result of the operation, \
2216 without modifying the original"]
2217 #[inline]
2218 pub const fn unsigned_abs(self) -> $UnsignedT {
2219 self.wrapping_abs() as $UnsignedT
2220 }
2221
2222 /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
2223 /// wrapping around at the boundary of the type.
2224 ///
2225 /// # Examples
2226 ///
2227 /// Basic usage:
2228 ///
2229 /// ```
2230 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(4), 81);")]
2231 /// assert_eq!(3i8.wrapping_pow(5), -13);
2232 /// assert_eq!(3i8.wrapping_pow(6), -39);
2233 /// ```
2234 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2235 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2236 #[must_use = "this returns the result of the operation, \
2237 without modifying the original"]
2238 #[inline]
2239 pub const fn wrapping_pow(self, mut exp: u32) -> Self {
2240 if exp == 0 {
2241 return 1;
2242 }
2243 let mut base = self;
2244 let mut acc: Self = 1;
2245
2246 if intrinsics::is_val_statically_known(exp) {
2247 while exp > 1 {
2248 if (exp & 1) == 1 {
2249 acc = acc.wrapping_mul(base);
2250 }
2251 exp /= 2;
2252 base = base.wrapping_mul(base);
2253 }
2254
2255 // since exp!=0, finally the exp must be 1.
2256 // Deal with the final bit of the exponent separately, since
2257 // squaring the base afterwards is not necessary.
2258 acc.wrapping_mul(base)
2259 } else {
2260 // This is faster than the above when the exponent is not known
2261 // at compile time. We can't use the same code for the constant
2262 // exponent case because LLVM is currently unable to unroll
2263 // this loop.
2264 loop {
2265 if (exp & 1) == 1 {
2266 acc = acc.wrapping_mul(base);
2267 // since exp!=0, finally the exp must be 1.
2268 if exp == 1 {
2269 return acc;
2270 }
2271 }
2272 exp /= 2;
2273 base = base.wrapping_mul(base);
2274 }
2275 }
2276 }
2277
2278 /// Calculates `self` + `rhs`.
2279 ///
2280 /// Returns a tuple of the addition along with a boolean indicating
2281 /// whether an arithmetic overflow would occur. If an overflow would have
2282 /// occurred then the wrapped value is returned.
2283 ///
2284 /// # Examples
2285 ///
2286 /// Basic usage:
2287 ///
2288 /// ```
2289 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
2290 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (", stringify!($SelfT), "::MIN, true));")]
2291 /// ```
2292 #[stable(feature = "wrapping", since = "1.7.0")]
2293 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2294 #[must_use = "this returns the result of the operation, \
2295 without modifying the original"]
2296 #[inline(always)]
2297 pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
2298 let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
2299 (a as Self, b)
2300 }
2301
2302 /// Calculates `self` + `rhs` + `carry` and checks for overflow.
2303 ///
2304 /// Performs "ternary addition" of two integer operands and a carry-in
2305 /// bit, and returns a tuple of the sum along with a boolean indicating
2306 /// whether an arithmetic overflow would occur. On overflow, the wrapped
2307 /// value is returned.
2308 ///
2309 /// This allows chaining together multiple additions to create a wider
2310 /// addition, and can be useful for bignum addition. This method should
2311 /// only be used for the most significant word; for the less significant
2312 /// words the unsigned method
2313 #[doc = concat!("[`", stringify!($UnsignedT), "::carrying_add`]")]
2314 /// should be used.
2315 ///
2316 /// The output boolean returned by this method is *not* a carry flag,
2317 /// and should *not* be added to a more significant word.
2318 ///
2319 /// If the input carry is false, this method is equivalent to
2320 /// [`overflowing_add`](Self::overflowing_add).
2321 ///
2322 /// # Examples
2323 ///
2324 /// ```
2325 /// #![feature(bigint_helper_methods)]
2326 /// // Only the most significant word is signed.
2327 /// //
2328 #[doc = concat!("// 10 MAX (a = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2329 #[doc = concat!("// + -5 9 (b = -5 × 2^", stringify!($BITS), " + 9)")]
2330 /// // ---------
2331 #[doc = concat!("// 6 8 (sum = 6 × 2^", stringify!($BITS), " + 8)")]
2332 ///
2333 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (10, ", stringify!($UnsignedT), "::MAX);")]
2334 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (-5, 9);")]
2335 /// let carry0 = false;
2336 ///
2337 #[doc = concat!("// ", stringify!($UnsignedT), "::carrying_add for the less significant words")]
2338 /// let (sum0, carry1) = a0.carrying_add(b0, carry0);
2339 /// assert_eq!(carry1, true);
2340 ///
2341 #[doc = concat!("// ", stringify!($SelfT), "::carrying_add for the most significant word")]
2342 /// let (sum1, overflow) = a1.carrying_add(b1, carry1);
2343 /// assert_eq!(overflow, false);
2344 ///
2345 /// assert_eq!((sum1, sum0), (6, 8));
2346 /// ```
2347 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2348 #[must_use = "this returns the result of the operation, \
2349 without modifying the original"]
2350 #[inline]
2351 pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
2352 // note: longer-term this should be done via an intrinsic.
2353 // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
2354 let (a, b) = self.overflowing_add(rhs);
2355 let (c, d) = a.overflowing_add(carry as $SelfT);
2356 (c, b != d)
2357 }
2358
2359 /// Calculates `self` + `rhs` with an unsigned `rhs`.
2360 ///
2361 /// Returns a tuple of the addition along with a boolean indicating
2362 /// whether an arithmetic overflow would occur. If an overflow would
2363 /// have occurred then the wrapped value is returned.
2364 ///
2365 /// # Examples
2366 ///
2367 /// Basic usage:
2368 ///
2369 /// ```
2370 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_unsigned(2), (3, false));")]
2371 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_add_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MAX, false));")]
2372 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_unsigned(3), (", stringify!($SelfT), "::MIN, true));")]
2373 /// ```
2374 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2375 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2376 #[must_use = "this returns the result of the operation, \
2377 without modifying the original"]
2378 #[inline]
2379 pub const fn overflowing_add_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
2380 let rhs = rhs as Self;
2381 let (res, overflowed) = self.overflowing_add(rhs);
2382 (res, overflowed ^ (rhs < 0))
2383 }
2384
2385 /// Calculates `self` - `rhs`.
2386 ///
2387 /// Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow
2388 /// would occur. If an overflow would have occurred then the wrapped value is returned.
2389 ///
2390 /// # Examples
2391 ///
2392 /// Basic usage:
2393 ///
2394 /// ```
2395 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
2396 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
2397 /// ```
2398 #[stable(feature = "wrapping", since = "1.7.0")]
2399 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2400 #[must_use = "this returns the result of the operation, \
2401 without modifying the original"]
2402 #[inline(always)]
2403 pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
2404 let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
2405 (a as Self, b)
2406 }
2407
2408 /// Calculates `self` − `rhs` − `borrow` and checks for
2409 /// overflow.
2410 ///
2411 /// Performs "ternary subtraction" by subtracting both an integer
2412 /// operand and a borrow-in bit from `self`, and returns a tuple of the
2413 /// difference along with a boolean indicating whether an arithmetic
2414 /// overflow would occur. On overflow, the wrapped value is returned.
2415 ///
2416 /// This allows chaining together multiple subtractions to create a
2417 /// wider subtraction, and can be useful for bignum subtraction. This
2418 /// method should only be used for the most significant word; for the
2419 /// less significant words the unsigned method
2420 #[doc = concat!("[`", stringify!($UnsignedT), "::borrowing_sub`]")]
2421 /// should be used.
2422 ///
2423 /// The output boolean returned by this method is *not* a borrow flag,
2424 /// and should *not* be subtracted from a more significant word.
2425 ///
2426 /// If the input borrow is false, this method is equivalent to
2427 /// [`overflowing_sub`](Self::overflowing_sub).
2428 ///
2429 /// # Examples
2430 ///
2431 /// ```
2432 /// #![feature(bigint_helper_methods)]
2433 /// // Only the most significant word is signed.
2434 /// //
2435 #[doc = concat!("// 6 8 (a = 6 × 2^", stringify!($BITS), " + 8)")]
2436 #[doc = concat!("// - -5 9 (b = -5 × 2^", stringify!($BITS), " + 9)")]
2437 /// // ---------
2438 #[doc = concat!("// 10 MAX (diff = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2439 ///
2440 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (6, 8);")]
2441 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (-5, 9);")]
2442 /// let borrow0 = false;
2443 ///
2444 #[doc = concat!("// ", stringify!($UnsignedT), "::borrowing_sub for the less significant words")]
2445 /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
2446 /// assert_eq!(borrow1, true);
2447 ///
2448 #[doc = concat!("// ", stringify!($SelfT), "::borrowing_sub for the most significant word")]
2449 /// let (diff1, overflow) = a1.borrowing_sub(b1, borrow1);
2450 /// assert_eq!(overflow, false);
2451 ///
2452 #[doc = concat!("assert_eq!((diff1, diff0), (10, ", stringify!($UnsignedT), "::MAX));")]
2453 /// ```
2454 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2455 #[must_use = "this returns the result of the operation, \
2456 without modifying the original"]
2457 #[inline]
2458 pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
2459 // note: longer-term this should be done via an intrinsic.
2460 // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
2461 let (a, b) = self.overflowing_sub(rhs);
2462 let (c, d) = a.overflowing_sub(borrow as $SelfT);
2463 (c, b != d)
2464 }
2465
2466 /// Calculates `self` - `rhs` with an unsigned `rhs`.
2467 ///
2468 /// Returns a tuple of the subtraction along with a boolean indicating
2469 /// whether an arithmetic overflow would occur. If an overflow would
2470 /// have occurred then the wrapped value is returned.
2471 ///
2472 /// # Examples
2473 ///
2474 /// Basic usage:
2475 ///
2476 /// ```
2477 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_unsigned(2), (-1, false));")]
2478 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).overflowing_sub_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MIN, false));")]
2479 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).overflowing_sub_unsigned(3), (", stringify!($SelfT), "::MAX, true));")]
2480 /// ```
2481 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2482 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2483 #[must_use = "this returns the result of the operation, \
2484 without modifying the original"]
2485 #[inline]
2486 pub const fn overflowing_sub_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
2487 let rhs = rhs as Self;
2488 let (res, overflowed) = self.overflowing_sub(rhs);
2489 (res, overflowed ^ (rhs < 0))
2490 }
2491
2492 /// Calculates the multiplication of `self` and `rhs`.
2493 ///
2494 /// Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow
2495 /// would occur. If an overflow would have occurred then the wrapped value is returned.
2496 ///
2497 /// # Examples
2498 ///
2499 /// Basic usage:
2500 ///
2501 /// ```
2502 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_mul(2), (10, false));")]
2503 /// assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));
2504 /// ```
2505 #[stable(feature = "wrapping", since = "1.7.0")]
2506 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2507 #[must_use = "this returns the result of the operation, \
2508 without modifying the original"]
2509 #[inline(always)]
2510 pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
2511 let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
2512 (a as Self, b)
2513 }
2514
2515 /// Calculates the complete product `self * rhs` without the possibility to overflow.
2516 ///
2517 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2518 /// of the result as two separate values, in that order.
2519 ///
2520 /// If you also need to add a carry to the wide result, then you want
2521 /// [`Self::carrying_mul`] instead.
2522 ///
2523 /// # Examples
2524 ///
2525 /// Basic usage:
2526 ///
2527 /// Please note that this example is shared between integer types.
2528 /// Which explains why `i32` is used here.
2529 ///
2530 /// ```
2531 /// #![feature(bigint_helper_methods)]
2532 /// assert_eq!(5i32.widening_mul(-2), (4294967286, -1));
2533 /// assert_eq!(1_000_000_000i32.widening_mul(-10), (2884901888, -3));
2534 /// ```
2535 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2536 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2537 #[must_use = "this returns the result of the operation, \
2538 without modifying the original"]
2539 #[inline]
2540 pub const fn widening_mul(self, rhs: Self) -> ($UnsignedT, Self) {
2541 Self::carrying_mul_add(self, rhs, 0, 0)
2542 }
2543
2544 /// Calculates the "full multiplication" `self * rhs + carry`
2545 /// without the possibility to overflow.
2546 ///
2547 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2548 /// of the result as two separate values, in that order.
2549 ///
2550 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2551 /// additional amount of overflow. This allows for chaining together multiple
2552 /// multiplications to create "big integers" which represent larger values.
2553 ///
2554 /// If you don't need the `carry`, then you can use [`Self::widening_mul`] instead.
2555 ///
2556 /// # Examples
2557 ///
2558 /// Basic usage:
2559 ///
2560 /// Please note that this example is shared between integer types.
2561 /// Which explains why `i32` is used here.
2562 ///
2563 /// ```
2564 /// #![feature(bigint_helper_methods)]
2565 /// assert_eq!(5i32.carrying_mul(-2, 0), (4294967286, -1));
2566 /// assert_eq!(5i32.carrying_mul(-2, 10), (0, 0));
2567 /// assert_eq!(1_000_000_000i32.carrying_mul(-10, 0), (2884901888, -3));
2568 /// assert_eq!(1_000_000_000i32.carrying_mul(-10, 10), (2884901898, -3));
2569 #[doc = concat!("assert_eq!(",
2570 stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2571 "(", stringify!($SelfT), "::MAX.unsigned_abs() + 1, ", stringify!($SelfT), "::MAX / 2));"
2572 )]
2573 /// ```
2574 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2575 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2576 #[must_use = "this returns the result of the operation, \
2577 without modifying the original"]
2578 #[inline]
2579 pub const fn carrying_mul(self, rhs: Self, carry: Self) -> ($UnsignedT, Self) {
2580 Self::carrying_mul_add(self, rhs, carry, 0)
2581 }
2582
2583 /// Calculates the "full multiplication" `self * rhs + carry1 + carry2`
2584 /// without the possibility to overflow.
2585 ///
2586 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2587 /// of the result as two separate values, in that order.
2588 ///
2589 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2590 /// additional amount of overflow. This allows for chaining together multiple
2591 /// multiplications to create "big integers" which represent larger values.
2592 ///
2593 /// If you don't need either `carry`, then you can use [`Self::widening_mul`] instead,
2594 /// and if you only need one `carry`, then you can use [`Self::carrying_mul`] instead.
2595 ///
2596 /// # Examples
2597 ///
2598 /// Basic usage:
2599 ///
2600 /// Please note that this example is shared between integer types.
2601 /// Which explains why `i32` is used here.
2602 ///
2603 /// ```
2604 /// #![feature(bigint_helper_methods)]
2605 /// assert_eq!(5i32.carrying_mul_add(-2, 0, 0), (4294967286, -1));
2606 /// assert_eq!(5i32.carrying_mul_add(-2, 10, 10), (10, 0));
2607 /// assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 0, 0), (2884901888, -3));
2608 /// assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 10, 10), (2884901908, -3));
2609 #[doc = concat!("assert_eq!(",
2610 stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2611 "(", stringify!($UnsignedT), "::MAX, ", stringify!($SelfT), "::MAX / 2));"
2612 )]
2613 /// ```
2614 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2615 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2616 #[must_use = "this returns the result of the operation, \
2617 without modifying the original"]
2618 #[inline]
2619 pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> ($UnsignedT, Self) {
2620 intrinsics::carrying_mul_add(self, rhs, carry, add)
2621 }
2622
2623 /// Calculates the divisor when `self` is divided by `rhs`.
2624 ///
2625 /// Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
2626 /// occur. If an overflow would occur then self is returned.
2627 ///
2628 /// # Panics
2629 ///
2630 /// This function will panic if `rhs` is zero.
2631 ///
2632 /// # Examples
2633 ///
2634 /// Basic usage:
2635 ///
2636 /// ```
2637 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
2638 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div(-1), (", stringify!($SelfT), "::MIN, true));")]
2639 /// ```
2640 #[inline]
2641 #[stable(feature = "wrapping", since = "1.7.0")]
2642 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2643 #[must_use = "this returns the result of the operation, \
2644 without modifying the original"]
2645 pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
2646 // Using `&` helps LLVM see that it is the same check made in division.
2647 if intrinsics::unlikely((self == Self::MIN) & (rhs == -1)) {
2648 (self, true)
2649 } else {
2650 (self / rhs, false)
2651 }
2652 }
2653
2654 /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`.
2655 ///
2656 /// Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
2657 /// occur. If an overflow would occur then `self` is returned.
2658 ///
2659 /// # Panics
2660 ///
2661 /// This function will panic if `rhs` is zero.
2662 ///
2663 /// # Examples
2664 ///
2665 /// Basic usage:
2666 ///
2667 /// ```
2668 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
2669 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div_euclid(-1), (", stringify!($SelfT), "::MIN, true));")]
2670 /// ```
2671 #[inline]
2672 #[stable(feature = "euclidean_division", since = "1.38.0")]
2673 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2674 #[must_use = "this returns the result of the operation, \
2675 without modifying the original"]
2676 pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
2677 // Using `&` helps LLVM see that it is the same check made in division.
2678 if intrinsics::unlikely((self == Self::MIN) & (rhs == -1)) {
2679 (self, true)
2680 } else {
2681 (self.div_euclid(rhs), false)
2682 }
2683 }
2684
2685 /// Calculates the remainder when `self` is divided by `rhs`.
2686 ///
2687 /// Returns a tuple of the remainder after dividing along with a boolean indicating whether an
2688 /// arithmetic overflow would occur. If an overflow would occur then 0 is returned.
2689 ///
2690 /// # Panics
2691 ///
2692 /// This function will panic if `rhs` is zero.
2693 ///
2694 /// # Examples
2695 ///
2696 /// Basic usage:
2697 ///
2698 /// ```
2699 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
2700 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem(-1), (0, true));")]
2701 /// ```
2702 #[inline]
2703 #[stable(feature = "wrapping", since = "1.7.0")]
2704 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2705 #[must_use = "this returns the result of the operation, \
2706 without modifying the original"]
2707 pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
2708 if intrinsics::unlikely(rhs == -1) {
2709 (0, self == Self::MIN)
2710 } else {
2711 (self % rhs, false)
2712 }
2713 }
2714
2715
2716 /// Overflowing Euclidean remainder. Calculates `self.rem_euclid(rhs)`.
2717 ///
2718 /// Returns a tuple of the remainder after dividing along with a boolean indicating whether an
2719 /// arithmetic overflow would occur. If an overflow would occur then 0 is returned.
2720 ///
2721 /// # Panics
2722 ///
2723 /// This function will panic if `rhs` is zero.
2724 ///
2725 /// # Examples
2726 ///
2727 /// Basic usage:
2728 ///
2729 /// ```
2730 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
2731 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem_euclid(-1), (0, true));")]
2732 /// ```
2733 #[stable(feature = "euclidean_division", since = "1.38.0")]
2734 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2735 #[must_use = "this returns the result of the operation, \
2736 without modifying the original"]
2737 #[inline]
2738 #[track_caller]
2739 pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
2740 if intrinsics::unlikely(rhs == -1) {
2741 (0, self == Self::MIN)
2742 } else {
2743 (self.rem_euclid(rhs), false)
2744 }
2745 }
2746
2747
2748 /// Negates self, overflowing if this is equal to the minimum value.
2749 ///
2750 /// Returns a tuple of the negated version of self along with a boolean indicating whether an overflow
2751 /// happened. If `self` is the minimum value (e.g., `i32::MIN` for values of type `i32`), then the
2752 /// minimum value will be returned again and `true` will be returned for an overflow happening.
2753 ///
2754 /// # Examples
2755 ///
2756 /// Basic usage:
2757 ///
2758 /// ```
2759 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2, false));")]
2760 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_neg(), (", stringify!($SelfT), "::MIN, true));")]
2761 /// ```
2762 #[inline]
2763 #[stable(feature = "wrapping", since = "1.7.0")]
2764 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2765 #[must_use = "this returns the result of the operation, \
2766 without modifying the original"]
2767 #[allow(unused_attributes)]
2768 pub const fn overflowing_neg(self) -> (Self, bool) {
2769 if intrinsics::unlikely(self == Self::MIN) {
2770 (Self::MIN, true)
2771 } else {
2772 (-self, false)
2773 }
2774 }
2775
2776 /// Shifts self left by `rhs` bits.
2777 ///
2778 /// Returns a tuple of the shifted version of self along with a boolean indicating whether the shift
2779 /// value was larger than or equal to the number of bits. If the shift value is too large, then value is
2780 /// masked (N-1) where N is the number of bits, and this value is then used to perform the shift.
2781 ///
2782 /// # Examples
2783 ///
2784 /// Basic usage:
2785 ///
2786 /// ```
2787 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT),".overflowing_shl(4), (0x10, false));")]
2788 /// assert_eq!(0x1i32.overflowing_shl(36), (0x10, true));
2789 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
2790 /// ```
2791 #[stable(feature = "wrapping", since = "1.7.0")]
2792 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2793 #[must_use = "this returns the result of the operation, \
2794 without modifying the original"]
2795 #[inline]
2796 pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
2797 (self.wrapping_shl(rhs), rhs >= Self::BITS)
2798 }
2799
2800 /// Shifts self right by `rhs` bits.
2801 ///
2802 /// Returns a tuple of the shifted version of self along with a boolean indicating whether the shift
2803 /// value was larger than or equal to the number of bits. If the shift value is too large, then value is
2804 /// masked (N-1) where N is the number of bits, and this value is then used to perform the shift.
2805 ///
2806 /// # Examples
2807 ///
2808 /// Basic usage:
2809 ///
2810 /// ```
2811 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
2812 /// assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
2813 /// ```
2814 #[stable(feature = "wrapping", since = "1.7.0")]
2815 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2816 #[must_use = "this returns the result of the operation, \
2817 without modifying the original"]
2818 #[inline]
2819 pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
2820 (self.wrapping_shr(rhs), rhs >= Self::BITS)
2821 }
2822
2823 /// Computes the absolute value of `self`.
2824 ///
2825 /// Returns a tuple of the absolute version of self along with a boolean indicating whether an overflow
2826 /// happened. If self is the minimum value
2827 #[doc = concat!("(e.g., ", stringify!($SelfT), "::MIN for values of type ", stringify!($SelfT), "),")]
2828 /// then the minimum value will be returned again and true will be returned
2829 /// for an overflow happening.
2830 ///
2831 /// # Examples
2832 ///
2833 /// Basic usage:
2834 ///
2835 /// ```
2836 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".overflowing_abs(), (10, false));")]
2837 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").overflowing_abs(), (10, false));")]
2838 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_abs(), (", stringify!($SelfT), "::MIN, true));")]
2839 /// ```
2840 #[stable(feature = "no_panic_abs", since = "1.13.0")]
2841 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2842 #[must_use = "this returns the result of the operation, \
2843 without modifying the original"]
2844 #[inline]
2845 pub const fn overflowing_abs(self) -> (Self, bool) {
2846 (self.wrapping_abs(), self == Self::MIN)
2847 }
2848
2849 /// Raises self to the power of `exp`, using exponentiation by squaring.
2850 ///
2851 /// Returns a tuple of the exponentiation along with a bool indicating
2852 /// whether an overflow happened.
2853 ///
2854 /// # Examples
2855 ///
2856 /// Basic usage:
2857 ///
2858 /// ```
2859 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(4), (81, false));")]
2860 /// assert_eq!(3i8.overflowing_pow(5), (-13, true));
2861 /// ```
2862 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2863 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2864 #[must_use = "this returns the result of the operation, \
2865 without modifying the original"]
2866 #[inline]
2867 pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
2868 if exp == 0 {
2869 return (1,false);
2870 }
2871 let mut base = self;
2872 let mut acc: Self = 1;
2873 let mut overflown = false;
2874 // Scratch space for storing results of overflowing_mul.
2875 let mut r;
2876
2877 loop {
2878 if (exp & 1) == 1 {
2879 r = acc.overflowing_mul(base);
2880 // since exp!=0, finally the exp must be 1.
2881 if exp == 1 {
2882 r.1 |= overflown;
2883 return r;
2884 }
2885 acc = r.0;
2886 overflown |= r.1;
2887 }
2888 exp /= 2;
2889 r = base.overflowing_mul(base);
2890 base = r.0;
2891 overflown |= r.1;
2892 }
2893 }
2894
2895 /// Raises self to the power of `exp`, using exponentiation by squaring.
2896 ///
2897 /// # Examples
2898 ///
2899 /// Basic usage:
2900 ///
2901 /// ```
2902 #[doc = concat!("let x: ", stringify!($SelfT), " = 2; // or any other integer type")]
2903 ///
2904 /// assert_eq!(x.pow(5), 32);
2905 /// ```
2906 #[stable(feature = "rust1", since = "1.0.0")]
2907 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2908 #[must_use = "this returns the result of the operation, \
2909 without modifying the original"]
2910 #[inline]
2911 #[rustc_inherit_overflow_checks]
2912 pub const fn pow(self, mut exp: u32) -> Self {
2913 if exp == 0 {
2914 return 1;
2915 }
2916 let mut base = self;
2917 let mut acc = 1;
2918
2919 if intrinsics::is_val_statically_known(exp) {
2920 while exp > 1 {
2921 if (exp & 1) == 1 {
2922 acc = acc * base;
2923 }
2924 exp /= 2;
2925 base = base * base;
2926 }
2927
2928 // since exp!=0, finally the exp must be 1.
2929 // Deal with the final bit of the exponent separately, since
2930 // squaring the base afterwards is not necessary and may cause a
2931 // needless overflow.
2932 acc * base
2933 } else {
2934 // This is faster than the above when the exponent is not known
2935 // at compile time. We can't use the same code for the constant
2936 // exponent case because LLVM is currently unable to unroll
2937 // this loop.
2938 loop {
2939 if (exp & 1) == 1 {
2940 acc = acc * base;
2941 // since exp!=0, finally the exp must be 1.
2942 if exp == 1 {
2943 return acc;
2944 }
2945 }
2946 exp /= 2;
2947 base = base * base;
2948 }
2949 }
2950 }
2951
2952 /// Returns the square root of the number, rounded down.
2953 ///
2954 /// # Panics
2955 ///
2956 /// This function will panic if `self` is negative.
2957 ///
2958 /// # Examples
2959 ///
2960 /// Basic usage:
2961 /// ```
2962 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
2963 /// ```
2964 #[stable(feature = "isqrt", since = "1.84.0")]
2965 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
2966 #[must_use = "this returns the result of the operation, \
2967 without modifying the original"]
2968 #[inline]
2969 #[track_caller]
2970 pub const fn isqrt(self) -> Self {
2971 match self.checked_isqrt() {
2972 Some(sqrt) => sqrt,
2973 None => crate::num::int_sqrt::panic_for_negative_argument(),
2974 }
2975 }
2976
2977 /// Calculates the quotient of Euclidean division of `self` by `rhs`.
2978 ///
2979 /// This computes the integer `q` such that `self = q * rhs + r`, with
2980 /// `r = self.rem_euclid(rhs)` and `0 <= r < abs(rhs)`.
2981 ///
2982 /// In other words, the result is `self / rhs` rounded to the integer `q`
2983 /// such that `self >= q * rhs`.
2984 /// If `self > 0`, this is equal to rounding towards zero (the default in Rust);
2985 /// if `self < 0`, this is equal to rounding away from zero (towards +/- infinity).
2986 /// If `rhs > 0`, this is equal to rounding towards -infinity;
2987 /// if `rhs < 0`, this is equal to rounding towards +infinity.
2988 ///
2989 /// # Panics
2990 ///
2991 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
2992 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
2993 ///
2994 /// # Examples
2995 ///
2996 /// Basic usage:
2997 ///
2998 /// ```
2999 #[doc = concat!("let a: ", stringify!($SelfT), " = 7; // or any other integer type")]
3000 /// let b = 4;
3001 ///
3002 /// assert_eq!(a.div_euclid(b), 1); // 7 >= 4 * 1
3003 /// assert_eq!(a.div_euclid(-b), -1); // 7 >= -4 * -1
3004 /// assert_eq!((-a).div_euclid(b), -2); // -7 >= 4 * -2
3005 /// assert_eq!((-a).div_euclid(-b), 2); // -7 >= -4 * 2
3006 /// ```
3007 #[stable(feature = "euclidean_division", since = "1.38.0")]
3008 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3009 #[must_use = "this returns the result of the operation, \
3010 without modifying the original"]
3011 #[inline]
3012 #[track_caller]
3013 pub const fn div_euclid(self, rhs: Self) -> Self {
3014 let q = self / rhs;
3015 if self % rhs < 0 {
3016 return if rhs > 0 { q - 1 } else { q + 1 }
3017 }
3018 q
3019 }
3020
3021
3022 /// Calculates the least nonnegative remainder of `self (mod rhs)`.
3023 ///
3024 /// This is done as if by the Euclidean division algorithm -- given
3025 /// `r = self.rem_euclid(rhs)`, the result satisfies
3026 /// `self = rhs * self.div_euclid(rhs) + r` and `0 <= r < abs(rhs)`.
3027 ///
3028 /// # Panics
3029 ///
3030 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN` and
3031 /// `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3032 ///
3033 /// # Examples
3034 ///
3035 /// Basic usage:
3036 ///
3037 /// ```
3038 #[doc = concat!("let a: ", stringify!($SelfT), " = 7; // or any other integer type")]
3039 /// let b = 4;
3040 ///
3041 /// assert_eq!(a.rem_euclid(b), 3);
3042 /// assert_eq!((-a).rem_euclid(b), 1);
3043 /// assert_eq!(a.rem_euclid(-b), 3);
3044 /// assert_eq!((-a).rem_euclid(-b), 1);
3045 /// ```
3046 ///
3047 /// This will panic:
3048 /// ```should_panic
3049 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.rem_euclid(-1);")]
3050 /// ```
3051 #[doc(alias = "modulo", alias = "mod")]
3052 #[stable(feature = "euclidean_division", since = "1.38.0")]
3053 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3054 #[must_use = "this returns the result of the operation, \
3055 without modifying the original"]
3056 #[inline]
3057 #[track_caller]
3058 pub const fn rem_euclid(self, rhs: Self) -> Self {
3059 let r = self % rhs;
3060 if r < 0 {
3061 // Semantically equivalent to `if rhs < 0 { r - rhs } else { r + rhs }`.
3062 // If `rhs` is not `Self::MIN`, then `r + abs(rhs)` will not overflow
3063 // and is clearly equivalent, because `r` is negative.
3064 // Otherwise, `rhs` is `Self::MIN`, then we have
3065 // `r.wrapping_add(Self::MIN.wrapping_abs())`, which evaluates
3066 // to `r.wrapping_add(Self::MIN)`, which is equivalent to
3067 // `r - Self::MIN`, which is what we wanted (and will not overflow
3068 // for negative `r`).
3069 r.wrapping_add(rhs.wrapping_abs())
3070 } else {
3071 r
3072 }
3073 }
3074
3075 /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
3076 ///
3077 /// # Panics
3078 ///
3079 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3080 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3081 ///
3082 /// # Examples
3083 ///
3084 /// Basic usage:
3085 ///
3086 /// ```
3087 /// #![feature(int_roundings)]
3088 #[doc = concat!("let a: ", stringify!($SelfT)," = 8;")]
3089 /// let b = 3;
3090 ///
3091 /// assert_eq!(a.div_floor(b), 2);
3092 /// assert_eq!(a.div_floor(-b), -3);
3093 /// assert_eq!((-a).div_floor(b), -3);
3094 /// assert_eq!((-a).div_floor(-b), 2);
3095 /// ```
3096 #[unstable(feature = "int_roundings", issue = "88581")]
3097 #[must_use = "this returns the result of the operation, \
3098 without modifying the original"]
3099 #[inline]
3100 #[track_caller]
3101 pub const fn div_floor(self, rhs: Self) -> Self {
3102 let d = self / rhs;
3103 let r = self % rhs;
3104
3105 // If the remainder is non-zero, we need to subtract one if the
3106 // signs of self and rhs differ, as this means we rounded upwards
3107 // instead of downwards. We do this branchlessly by creating a mask
3108 // which is all-ones iff the signs differ, and 0 otherwise. Then by
3109 // adding this mask (which corresponds to the signed value -1), we
3110 // get our correction.
3111 let correction = (self ^ rhs) >> (Self::BITS - 1);
3112 if r != 0 {
3113 d + correction
3114 } else {
3115 d
3116 }
3117 }
3118
3119 /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
3120 ///
3121 /// # Panics
3122 ///
3123 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3124 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3125 ///
3126 /// # Examples
3127 ///
3128 /// Basic usage:
3129 ///
3130 /// ```
3131 /// #![feature(int_roundings)]
3132 #[doc = concat!("let a: ", stringify!($SelfT)," = 8;")]
3133 /// let b = 3;
3134 ///
3135 /// assert_eq!(a.div_ceil(b), 3);
3136 /// assert_eq!(a.div_ceil(-b), -2);
3137 /// assert_eq!((-a).div_ceil(b), -2);
3138 /// assert_eq!((-a).div_ceil(-b), 3);
3139 /// ```
3140 #[unstable(feature = "int_roundings", issue = "88581")]
3141 #[must_use = "this returns the result of the operation, \
3142 without modifying the original"]
3143 #[inline]
3144 #[track_caller]
3145 pub const fn div_ceil(self, rhs: Self) -> Self {
3146 let d = self / rhs;
3147 let r = self % rhs;
3148
3149 // When remainder is non-zero we have a.div_ceil(b) == 1 + a.div_floor(b),
3150 // so we can re-use the algorithm from div_floor, just adding 1.
3151 let correction = 1 + ((self ^ rhs) >> (Self::BITS - 1));
3152 if r != 0 {
3153 d + correction
3154 } else {
3155 d
3156 }
3157 }
3158
3159 /// If `rhs` is positive, calculates the smallest value greater than or
3160 /// equal to `self` that is a multiple of `rhs`. If `rhs` is negative,
3161 /// calculates the largest value less than or equal to `self` that is a
3162 /// multiple of `rhs`.
3163 ///
3164 /// # Panics
3165 ///
3166 /// This function will panic if `rhs` is zero.
3167 ///
3168 /// ## Overflow behavior
3169 ///
3170 /// On overflow, this function will panic if overflow checks are enabled (default in debug
3171 /// mode) and wrap if overflow checks are disabled (default in release mode).
3172 ///
3173 /// # Examples
3174 ///
3175 /// Basic usage:
3176 ///
3177 /// ```
3178 /// #![feature(int_roundings)]
3179 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
3180 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
3181 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(-8), 16);")]
3182 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(-8), 16);")]
3183 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").next_multiple_of(8), -16);")]
3184 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").next_multiple_of(8), -16);")]
3185 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").next_multiple_of(-8), -16);")]
3186 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").next_multiple_of(-8), -24);")]
3187 /// ```
3188 #[unstable(feature = "int_roundings", issue = "88581")]
3189 #[must_use = "this returns the result of the operation, \
3190 without modifying the original"]
3191 #[inline]
3192 #[rustc_inherit_overflow_checks]
3193 pub const fn next_multiple_of(self, rhs: Self) -> Self {
3194 // This would otherwise fail when calculating `r` when self == T::MIN.
3195 if rhs == -1 {
3196 return self;
3197 }
3198
3199 let r = self % rhs;
3200 let m = if (r > 0 && rhs < 0) || (r < 0 && rhs > 0) {
3201 r + rhs
3202 } else {
3203 r
3204 };
3205
3206 if m == 0 {
3207 self
3208 } else {
3209 self + (rhs - m)
3210 }
3211 }
3212
3213 /// If `rhs` is positive, calculates the smallest value greater than or
3214 /// equal to `self` that is a multiple of `rhs`. If `rhs` is negative,
3215 /// calculates the largest value less than or equal to `self` that is a
3216 /// multiple of `rhs`. Returns `None` if `rhs` is zero or the operation
3217 /// would result in overflow.
3218 ///
3219 /// # Examples
3220 ///
3221 /// Basic usage:
3222 ///
3223 /// ```
3224 /// #![feature(int_roundings)]
3225 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
3226 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
3227 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(-8), Some(16));")]
3228 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(-8), Some(16));")]
3229 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").checked_next_multiple_of(8), Some(-16));")]
3230 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").checked_next_multiple_of(8), Some(-16));")]
3231 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").checked_next_multiple_of(-8), Some(-16));")]
3232 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").checked_next_multiple_of(-8), Some(-24));")]
3233 #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
3234 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
3235 /// ```
3236 #[unstable(feature = "int_roundings", issue = "88581")]
3237 #[must_use = "this returns the result of the operation, \
3238 without modifying the original"]
3239 #[inline]
3240 pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
3241 // This would otherwise fail when calculating `r` when self == T::MIN.
3242 if rhs == -1 {
3243 return Some(self);
3244 }
3245
3246 let r = try_opt!(self.checked_rem(rhs));
3247 let m = if (r > 0 && rhs < 0) || (r < 0 && rhs > 0) {
3248 // r + rhs cannot overflow because they have opposite signs
3249 r + rhs
3250 } else {
3251 r
3252 };
3253
3254 if m == 0 {
3255 Some(self)
3256 } else {
3257 // rhs - m cannot overflow because m has the same sign as rhs
3258 self.checked_add(rhs - m)
3259 }
3260 }
3261
3262 /// Returns the logarithm of the number with respect to an arbitrary base,
3263 /// rounded down.
3264 ///
3265 /// This method might not be optimized owing to implementation details;
3266 /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
3267 /// can produce results more efficiently for base 10.
3268 ///
3269 /// # Panics
3270 ///
3271 /// This function will panic if `self` is less than or equal to zero,
3272 /// or if `base` is less than 2.
3273 ///
3274 /// # Examples
3275 ///
3276 /// ```
3277 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
3278 /// ```
3279 #[stable(feature = "int_log", since = "1.67.0")]
3280 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3281 #[must_use = "this returns the result of the operation, \
3282 without modifying the original"]
3283 #[inline]
3284 #[track_caller]
3285 pub const fn ilog(self, base: Self) -> u32 {
3286 assert!(base >= 2, "base of integer logarithm must be at least 2");
3287 if let Some(log) = self.checked_ilog(base) {
3288 log
3289 } else {
3290 int_log10::panic_for_nonpositive_argument()
3291 }
3292 }
3293
3294 /// Returns the base 2 logarithm of the number, rounded down.
3295 ///
3296 /// # Panics
3297 ///
3298 /// This function will panic if `self` is less than or equal to zero.
3299 ///
3300 /// # Examples
3301 ///
3302 /// ```
3303 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
3304 /// ```
3305 #[stable(feature = "int_log", since = "1.67.0")]
3306 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3307 #[must_use = "this returns the result of the operation, \
3308 without modifying the original"]
3309 #[inline]
3310 #[track_caller]
3311 pub const fn ilog2(self) -> u32 {
3312 if let Some(log) = self.checked_ilog2() {
3313 log
3314 } else {
3315 int_log10::panic_for_nonpositive_argument()
3316 }
3317 }
3318
3319 /// Returns the base 10 logarithm of the number, rounded down.
3320 ///
3321 /// # Panics
3322 ///
3323 /// This function will panic if `self` is less than or equal to zero.
3324 ///
3325 /// # Example
3326 ///
3327 /// ```
3328 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
3329 /// ```
3330 #[stable(feature = "int_log", since = "1.67.0")]
3331 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3332 #[must_use = "this returns the result of the operation, \
3333 without modifying the original"]
3334 #[inline]
3335 #[track_caller]
3336 pub const fn ilog10(self) -> u32 {
3337 if let Some(log) = self.checked_ilog10() {
3338 log
3339 } else {
3340 int_log10::panic_for_nonpositive_argument()
3341 }
3342 }
3343
3344 /// Returns the logarithm of the number with respect to an arbitrary base,
3345 /// rounded down.
3346 ///
3347 /// Returns `None` if the number is negative or zero, or if the base is not at least 2.
3348 ///
3349 /// This method might not be optimized owing to implementation details;
3350 /// `checked_ilog2` can produce results more efficiently for base 2, and
3351 /// `checked_ilog10` can produce results more efficiently for base 10.
3352 ///
3353 /// # Examples
3354 ///
3355 /// ```
3356 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
3357 /// ```
3358 #[stable(feature = "int_log", since = "1.67.0")]
3359 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3360 #[must_use = "this returns the result of the operation, \
3361 without modifying the original"]
3362 #[inline]
3363 pub const fn checked_ilog(self, base: Self) -> Option<u32> {
3364 if self <= 0 || base <= 1 {
3365 None
3366 } else {
3367 // Delegate to the unsigned implementation.
3368 // The condition makes sure that both casts are exact.
3369 (self as $UnsignedT).checked_ilog(base as $UnsignedT)
3370 }
3371 }
3372
3373 /// Returns the base 2 logarithm of the number, rounded down.
3374 ///
3375 /// Returns `None` if the number is negative or zero.
3376 ///
3377 /// # Examples
3378 ///
3379 /// ```
3380 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
3381 /// ```
3382 #[stable(feature = "int_log", since = "1.67.0")]
3383 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3384 #[must_use = "this returns the result of the operation, \
3385 without modifying the original"]
3386 #[inline]
3387 pub const fn checked_ilog2(self) -> Option<u32> {
3388 if self <= 0 {
3389 None
3390 } else {
3391 // SAFETY: We just checked that this number is positive
3392 let log = (Self::BITS - 1) - unsafe { intrinsics::ctlz_nonzero(self) as u32 };
3393 Some(log)
3394 }
3395 }
3396
3397 /// Returns the base 10 logarithm of the number, rounded down.
3398 ///
3399 /// Returns `None` if the number is negative or zero.
3400 ///
3401 /// # Example
3402 ///
3403 /// ```
3404 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
3405 /// ```
3406 #[stable(feature = "int_log", since = "1.67.0")]
3407 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3408 #[must_use = "this returns the result of the operation, \
3409 without modifying the original"]
3410 #[inline]
3411 pub const fn checked_ilog10(self) -> Option<u32> {
3412 if self > 0 {
3413 Some(int_log10::$ActualT(self as $ActualT))
3414 } else {
3415 None
3416 }
3417 }
3418
3419 /// Computes the absolute value of `self`.
3420 ///
3421 /// # Overflow behavior
3422 ///
3423 /// The absolute value of
3424 #[doc = concat!("`", stringify!($SelfT), "::MIN`")]
3425 /// cannot be represented as an
3426 #[doc = concat!("`", stringify!($SelfT), "`,")]
3427 /// and attempting to calculate it will cause an overflow. This means
3428 /// that code in debug mode will trigger a panic on this case and
3429 /// optimized code will return
3430 #[doc = concat!("`", stringify!($SelfT), "::MIN`")]
3431 /// without a panic. If you do not want this behavior, consider
3432 /// using [`unsigned_abs`](Self::unsigned_abs) instead.
3433 ///
3434 /// # Examples
3435 ///
3436 /// Basic usage:
3437 ///
3438 /// ```
3439 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".abs(), 10);")]
3440 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").abs(), 10);")]
3441 /// ```
3442 #[stable(feature = "rust1", since = "1.0.0")]
3443 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3444 #[allow(unused_attributes)]
3445 #[must_use = "this returns the result of the operation, \
3446 without modifying the original"]
3447 #[inline]
3448 #[rustc_inherit_overflow_checks]
3449 pub const fn abs(self) -> Self {
3450 // Note that the #[rustc_inherit_overflow_checks] and #[inline]
3451 // above mean that the overflow semantics of the subtraction
3452 // depend on the crate we're being called from.
3453 if self.is_negative() {
3454 -self
3455 } else {
3456 self
3457 }
3458 }
3459
3460 /// Computes the absolute difference between `self` and `other`.
3461 ///
3462 /// This function always returns the correct answer without overflow or
3463 /// panics by returning an unsigned integer.
3464 ///
3465 /// # Examples
3466 ///
3467 /// Basic usage:
3468 ///
3469 /// ```
3470 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($UnsignedT), ");")]
3471 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($UnsignedT), ");")]
3472 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").abs_diff(80), 180", stringify!($UnsignedT), ");")]
3473 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").abs_diff(-120), 20", stringify!($UnsignedT), ");")]
3474 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.abs_diff(", stringify!($SelfT), "::MAX), ", stringify!($UnsignedT), "::MAX);")]
3475 /// ```
3476 #[stable(feature = "int_abs_diff", since = "1.60.0")]
3477 #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
3478 #[must_use = "this returns the result of the operation, \
3479 without modifying the original"]
3480 #[inline]
3481 pub const fn abs_diff(self, other: Self) -> $UnsignedT {
3482 if self < other {
3483 // Converting a non-negative x from signed to unsigned by using
3484 // `x as U` is left unchanged, but a negative x is converted
3485 // to value x + 2^N. Thus if `s` and `o` are binary variables
3486 // respectively indicating whether `self` and `other` are
3487 // negative, we are computing the mathematical value:
3488 //
3489 // (other + o*2^N) - (self + s*2^N) mod 2^N
3490 // other - self + (o-s)*2^N mod 2^N
3491 // other - self mod 2^N
3492 //
3493 // Finally, taking the mod 2^N of the mathematical value of
3494 // `other - self` does not change it as it already is
3495 // in the range [0, 2^N).
3496 (other as $UnsignedT).wrapping_sub(self as $UnsignedT)
3497 } else {
3498 (self as $UnsignedT).wrapping_sub(other as $UnsignedT)
3499 }
3500 }
3501
3502 /// Returns a number representing sign of `self`.
3503 ///
3504 /// - `0` if the number is zero
3505 /// - `1` if the number is positive
3506 /// - `-1` if the number is negative
3507 ///
3508 /// # Examples
3509 ///
3510 /// Basic usage:
3511 ///
3512 /// ```
3513 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".signum(), 1);")]
3514 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".signum(), 0);")]
3515 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").signum(), -1);")]
3516 /// ```
3517 #[stable(feature = "rust1", since = "1.0.0")]
3518 #[rustc_const_stable(feature = "const_int_sign", since = "1.47.0")]
3519 #[must_use = "this returns the result of the operation, \
3520 without modifying the original"]
3521 #[inline(always)]
3522 pub const fn signum(self) -> Self {
3523 // Picking the right way to phrase this is complicated
3524 // (<https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>)
3525 // so delegate it to `Ord` which is already producing -1/0/+1
3526 // exactly like we need and can be the place to deal with the complexity.
3527
3528 // FIXME(const-hack): replace with cmp
3529 if self < 0 { -1 }
3530 else if self == 0 { 0 }
3531 else { 1 }
3532 }
3533
3534 /// Returns `true` if `self` is positive and `false` if the number is zero or
3535 /// negative.
3536 ///
3537 /// # Examples
3538 ///
3539 /// Basic usage:
3540 ///
3541 /// ```
3542 #[doc = concat!("assert!(10", stringify!($SelfT), ".is_positive());")]
3543 #[doc = concat!("assert!(!(-10", stringify!($SelfT), ").is_positive());")]
3544 /// ```
3545 #[must_use]
3546 #[stable(feature = "rust1", since = "1.0.0")]
3547 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3548 #[inline(always)]
3549 pub const fn is_positive(self) -> bool { self > 0 }
3550
3551 /// Returns `true` if `self` is negative and `false` if the number is zero or
3552 /// positive.
3553 ///
3554 /// # Examples
3555 ///
3556 /// Basic usage:
3557 ///
3558 /// ```
3559 #[doc = concat!("assert!((-10", stringify!($SelfT), ").is_negative());")]
3560 #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_negative());")]
3561 /// ```
3562 #[must_use]
3563 #[stable(feature = "rust1", since = "1.0.0")]
3564 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3565 #[inline(always)]
3566 pub const fn is_negative(self) -> bool { self < 0 }
3567
3568 /// Returns the memory representation of this integer as a byte array in
3569 /// big-endian (network) byte order.
3570 ///
3571 #[doc = $to_xe_bytes_doc]
3572 ///
3573 /// # Examples
3574 ///
3575 /// ```
3576 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
3577 #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
3578 /// ```
3579 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3580 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3581 #[must_use = "this returns the result of the operation, \
3582 without modifying the original"]
3583 #[inline]
3584 pub const fn to_be_bytes(self) -> [u8; mem::size_of::<Self>()] {
3585 self.to_be().to_ne_bytes()
3586 }
3587
3588 /// Returns the memory representation of this integer as a byte array in
3589 /// little-endian byte order.
3590 ///
3591 #[doc = $to_xe_bytes_doc]
3592 ///
3593 /// # Examples
3594 ///
3595 /// ```
3596 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
3597 #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
3598 /// ```
3599 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3600 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3601 #[must_use = "this returns the result of the operation, \
3602 without modifying the original"]
3603 #[inline]
3604 pub const fn to_le_bytes(self) -> [u8; mem::size_of::<Self>()] {
3605 self.to_le().to_ne_bytes()
3606 }
3607
3608 /// Returns the memory representation of this integer as a byte array in
3609 /// native byte order.
3610 ///
3611 /// As the target platform's native endianness is used, portable code
3612 /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
3613 /// instead.
3614 ///
3615 #[doc = $to_xe_bytes_doc]
3616 ///
3617 /// [`to_be_bytes`]: Self::to_be_bytes
3618 /// [`to_le_bytes`]: Self::to_le_bytes
3619 ///
3620 /// # Examples
3621 ///
3622 /// ```
3623 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
3624 /// assert_eq!(
3625 /// bytes,
3626 /// if cfg!(target_endian = "big") {
3627 #[doc = concat!(" ", $be_bytes)]
3628 /// } else {
3629 #[doc = concat!(" ", $le_bytes)]
3630 /// }
3631 /// );
3632 /// ```
3633 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3634 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3635 // SAFETY: const sound because integers are plain old datatypes so we can always
3636 // transmute them to arrays of bytes
3637 #[must_use = "this returns the result of the operation, \
3638 without modifying the original"]
3639 #[inline]
3640 pub const fn to_ne_bytes(self) -> [u8; mem::size_of::<Self>()] {
3641 // SAFETY: integers are plain old datatypes so we can always transmute them to
3642 // arrays of bytes
3643 unsafe { mem::transmute(self) }
3644 }
3645
3646 /// Creates an integer value from its representation as a byte array in
3647 /// big endian.
3648 ///
3649 #[doc = $from_xe_bytes_doc]
3650 ///
3651 /// # Examples
3652 ///
3653 /// ```
3654 #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
3655 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3656 /// ```
3657 ///
3658 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3659 ///
3660 /// ```
3661 #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3662 #[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
3663 /// *input = rest;
3664 #[doc = concat!(" ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
3665 /// }
3666 /// ```
3667 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3668 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3669 #[must_use]
3670 #[inline]
3671 pub const fn from_be_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
3672 Self::from_be(Self::from_ne_bytes(bytes))
3673 }
3674
3675 /// Creates an integer value from its representation as a byte array in
3676 /// little endian.
3677 ///
3678 #[doc = $from_xe_bytes_doc]
3679 ///
3680 /// # Examples
3681 ///
3682 /// ```
3683 #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
3684 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3685 /// ```
3686 ///
3687 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3688 ///
3689 /// ```
3690 #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3691 #[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
3692 /// *input = rest;
3693 #[doc = concat!(" ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
3694 /// }
3695 /// ```
3696 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3697 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3698 #[must_use]
3699 #[inline]
3700 pub const fn from_le_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
3701 Self::from_le(Self::from_ne_bytes(bytes))
3702 }
3703
3704 /// Creates an integer value from its memory representation as a byte
3705 /// array in native endianness.
3706 ///
3707 /// As the target platform's native endianness is used, portable code
3708 /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
3709 /// appropriate instead.
3710 ///
3711 /// [`from_be_bytes`]: Self::from_be_bytes
3712 /// [`from_le_bytes`]: Self::from_le_bytes
3713 ///
3714 #[doc = $from_xe_bytes_doc]
3715 ///
3716 /// # Examples
3717 ///
3718 /// ```
3719 #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
3720 #[doc = concat!(" ", $be_bytes)]
3721 /// } else {
3722 #[doc = concat!(" ", $le_bytes)]
3723 /// });
3724 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3725 /// ```
3726 ///
3727 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3728 ///
3729 /// ```
3730 #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3731 #[doc = concat!(" let (int_bytes, rest) = input.split_at(std::mem::size_of::<", stringify!($SelfT), ">());")]
3732 /// *input = rest;
3733 #[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
3734 /// }
3735 /// ```
3736 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3737 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3738 #[must_use]
3739 // SAFETY: const sound because integers are plain old datatypes so we can always
3740 // transmute to them
3741 #[inline]
3742 pub const fn from_ne_bytes(bytes: [u8; mem::size_of::<Self>()]) -> Self {
3743 // SAFETY: integers are plain old datatypes so we can always transmute to them
3744 unsafe { mem::transmute(bytes) }
3745 }
3746
3747 /// New code should prefer to use
3748 #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
3749 ///
3750 /// Returns the smallest value that can be represented by this integer type.
3751 #[stable(feature = "rust1", since = "1.0.0")]
3752 #[inline(always)]
3753 #[rustc_promotable]
3754 #[rustc_const_stable(feature = "const_min_value", since = "1.32.0")]
3755 #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
3756 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
3757 pub const fn min_value() -> Self {
3758 Self::MIN
3759 }
3760
3761 /// New code should prefer to use
3762 #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
3763 ///
3764 /// Returns the largest value that can be represented by this integer type.
3765 #[stable(feature = "rust1", since = "1.0.0")]
3766 #[inline(always)]
3767 #[rustc_promotable]
3768 #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
3769 #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
3770 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
3771 pub const fn max_value() -> Self {
3772 Self::MAX
3773 }
3774 }
3775}