core/num/int_macros.rs
1macro_rules! int_impl {
2 (
3 Self = $SelfT:ty,
4 ActualT = $ActualT:ident,
5 UnsignedT = $UnsignedT:ty,
6
7 // These are all for use *only* in doc comments.
8 // As such, they're all passed as literals -- passing them as a string
9 // literal is fine if they need to be multiple code tokens.
10 // In non-comments, use the associated constants rather than these.
11 BITS = $BITS:literal,
12 BITS_MINUS_ONE = $BITS_MINUS_ONE:literal,
13 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>", $bound_condition, ").")]
29 ///
30 /// # Examples
31 ///
32 /// ```
33 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, ", stringify!($Min), ");")]
34 /// ```
35 #[stable(feature = "assoc_int_consts", since = "1.43.0")]
36 pub const MIN: Self = !Self::MAX;
37
38 /// The largest value that can be represented by this integer type
39 #[doc = concat!("(2<sup>", $BITS_MINUS_ONE, "</sup> − 1", $bound_condition, ").")]
40 ///
41 /// # Examples
42 ///
43 /// ```
44 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($Max), ");")]
45 /// ```
46 #[stable(feature = "assoc_int_consts", since = "1.43.0")]
47 pub const MAX: Self = (<$UnsignedT>::MAX >> 1) as Self;
48
49 /// The size of this integer type in bits.
50 ///
51 /// # Examples
52 ///
53 /// ```
54 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")]
55 /// ```
56 #[stable(feature = "int_bits_const", since = "1.53.0")]
57 pub const BITS: u32 = <$UnsignedT>::BITS;
58
59 /// Returns the number of ones in the binary representation of `self`.
60 ///
61 /// # Examples
62 ///
63 /// ```
64 #[doc = concat!("let n = 0b100_0000", stringify!($SelfT), ";")]
65 ///
66 /// assert_eq!(n.count_ones(), 1);
67 /// ```
68 ///
69 #[stable(feature = "rust1", since = "1.0.0")]
70 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
71 #[doc(alias = "popcount")]
72 #[doc(alias = "popcnt")]
73 #[must_use = "this returns the result of the operation, \
74 without modifying the original"]
75 #[inline(always)]
76 pub const fn count_ones(self) -> u32 { (self as $UnsignedT).count_ones() }
77
78 /// Returns the number of zeros in the binary representation of `self`.
79 ///
80 /// # Examples
81 ///
82 /// ```
83 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.count_zeros(), 1);")]
84 /// ```
85 #[stable(feature = "rust1", since = "1.0.0")]
86 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
87 #[must_use = "this returns the result of the operation, \
88 without modifying the original"]
89 #[inline(always)]
90 pub const fn count_zeros(self) -> u32 {
91 (!self).count_ones()
92 }
93
94 /// Returns the number of leading zeros in the binary representation of `self`.
95 ///
96 /// Depending on what you're doing with the value, you might also be interested in the
97 /// [`ilog2`] function which returns a consistent number, even if the type widens.
98 ///
99 /// # Examples
100 ///
101 /// ```
102 #[doc = concat!("let n = -1", stringify!($SelfT), ";")]
103 ///
104 /// assert_eq!(n.leading_zeros(), 0);
105 /// ```
106 #[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")]
107 #[stable(feature = "rust1", since = "1.0.0")]
108 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
109 #[must_use = "this returns the result of the operation, \
110 without modifying the original"]
111 #[inline(always)]
112 pub const fn leading_zeros(self) -> u32 {
113 (self as $UnsignedT).leading_zeros()
114 }
115
116 /// Returns the number of trailing zeros in the binary representation of `self`.
117 ///
118 /// # Examples
119 ///
120 /// ```
121 #[doc = concat!("let n = -4", stringify!($SelfT), ";")]
122 ///
123 /// assert_eq!(n.trailing_zeros(), 2);
124 /// ```
125 #[stable(feature = "rust1", since = "1.0.0")]
126 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
127 #[must_use = "this returns the result of the operation, \
128 without modifying the original"]
129 #[inline(always)]
130 pub const fn trailing_zeros(self) -> u32 {
131 (self as $UnsignedT).trailing_zeros()
132 }
133
134 /// Returns the number of leading ones in the binary representation of `self`.
135 ///
136 /// # Examples
137 ///
138 /// ```
139 #[doc = concat!("let n = -1", stringify!($SelfT), ";")]
140 ///
141 #[doc = concat!("assert_eq!(n.leading_ones(), ", stringify!($BITS), ");")]
142 /// ```
143 #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
144 #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
145 #[must_use = "this returns the result of the operation, \
146 without modifying the original"]
147 #[inline(always)]
148 pub const fn leading_ones(self) -> u32 {
149 (self as $UnsignedT).leading_ones()
150 }
151
152 /// Returns the number of trailing ones in the binary representation of `self`.
153 ///
154 /// # Examples
155 ///
156 /// ```
157 #[doc = concat!("let n = 3", stringify!($SelfT), ";")]
158 ///
159 /// assert_eq!(n.trailing_ones(), 2);
160 /// ```
161 #[stable(feature = "leading_trailing_ones", since = "1.46.0")]
162 #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")]
163 #[must_use = "this returns the result of the operation, \
164 without modifying the original"]
165 #[inline(always)]
166 pub const fn trailing_ones(self) -> u32 {
167 (self as $UnsignedT).trailing_ones()
168 }
169
170 /// Returns `self` with only the most significant bit set, or `0` if
171 /// the input is `0`.
172 ///
173 /// # Examples
174 ///
175 /// ```
176 /// #![feature(isolate_most_least_significant_one)]
177 ///
178 #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
179 ///
180 /// assert_eq!(n.isolate_highest_one(), 0b_01000000);
181 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_highest_one(), 0);")]
182 /// ```
183 #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
184 #[must_use = "this returns the result of the operation, \
185 without modifying the original"]
186 #[inline(always)]
187 pub const fn isolate_highest_one(self) -> Self {
188 self & (((1 as $SelfT) << (<$SelfT>::BITS - 1)).wrapping_shr(self.leading_zeros()))
189 }
190
191 /// Returns `self` with only the least significant bit set, or `0` if
192 /// the input is `0`.
193 ///
194 /// # Examples
195 ///
196 /// ```
197 /// #![feature(isolate_most_least_significant_one)]
198 ///
199 #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
200 ///
201 /// assert_eq!(n.isolate_lowest_one(), 0b_00000100);
202 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_lowest_one(), 0);")]
203 /// ```
204 #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")]
205 #[must_use = "this returns the result of the operation, \
206 without modifying the original"]
207 #[inline(always)]
208 pub const fn isolate_lowest_one(self) -> Self {
209 self & self.wrapping_neg()
210 }
211
212 /// Returns the index of the highest bit set to one in `self`, or `None`
213 /// if `self` is `0`.
214 ///
215 /// # Examples
216 ///
217 /// ```
218 /// #![feature(int_lowest_highest_one)]
219 ///
220 #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".highest_one(), None);")]
221 #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".highest_one(), Some(0));")]
222 #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".highest_one(), Some(4));")]
223 #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".highest_one(), Some(4));")]
224 /// ```
225 #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
226 #[must_use = "this returns the result of the operation, \
227 without modifying the original"]
228 #[inline(always)]
229 pub const fn highest_one(self) -> Option<u32> {
230 (self as $UnsignedT).highest_one()
231 }
232
233 /// Returns the index of the lowest bit set to one in `self`, or `None`
234 /// if `self` is `0`.
235 ///
236 /// # Examples
237 ///
238 /// ```
239 /// #![feature(int_lowest_highest_one)]
240 ///
241 #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".lowest_one(), None);")]
242 #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
243 #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".lowest_one(), Some(4));")]
244 #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".lowest_one(), Some(0));")]
245 /// ```
246 #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
247 #[must_use = "this returns the result of the operation, \
248 without modifying the original"]
249 #[inline(always)]
250 pub const fn lowest_one(self) -> Option<u32> {
251 (self as $UnsignedT).lowest_one()
252 }
253
254 /// Returns the bit pattern of `self` reinterpreted as an unsigned integer of the same size.
255 ///
256 /// This produces the same result as an `as` cast, but ensures that the bit-width remains
257 /// the same.
258 ///
259 /// # Examples
260 ///
261 /// ```
262 #[doc = concat!("let n = -1", stringify!($SelfT), ";")]
263 ///
264 #[doc = concat!("assert_eq!(n.cast_unsigned(), ", stringify!($UnsignedT), "::MAX);")]
265 /// ```
266 #[stable(feature = "integer_sign_cast", since = "1.87.0")]
267 #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
268 #[must_use = "this returns the result of the operation, \
269 without modifying the original"]
270 #[inline(always)]
271 pub const fn cast_unsigned(self) -> $UnsignedT {
272 self as $UnsignedT
273 }
274
275 /// Shifts the bits to the left by a specified amount, `n`,
276 /// wrapping the truncated bits to the end of the resulting integer.
277 ///
278 /// `rotate_left(n)` is equivalent to applying `rotate_left(1)` a total of `n` times. In
279 /// particular, a rotation by the number of bits in `self` returns the input value
280 /// unchanged.
281 ///
282 /// Please note this isn't the same operation as the `<<` shifting operator!
283 ///
284 /// # Examples
285 ///
286 /// ```
287 #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
288 #[doc = concat!("let m = ", $rot_result, ";")]
289 ///
290 #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
291 #[doc = concat!("assert_eq!(n.rotate_left(1024), n);")]
292 /// ```
293 #[stable(feature = "rust1", since = "1.0.0")]
294 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
295 #[must_use = "this returns the result of the operation, \
296 without modifying the original"]
297 #[inline(always)]
298 pub const fn rotate_left(self, n: u32) -> Self {
299 (self as $UnsignedT).rotate_left(n) as Self
300 }
301
302 /// Shifts the bits to the right by a specified amount, `n`,
303 /// wrapping the truncated bits to the beginning of the resulting
304 /// integer.
305 ///
306 /// `rotate_right(n)` is equivalent to applying `rotate_right(1)` a total of `n` times. In
307 /// particular, a rotation by the number of bits in `self` returns the input value
308 /// unchanged.
309 ///
310 /// Please note this isn't the same operation as the `>>` shifting operator!
311 ///
312 /// # Examples
313 ///
314 /// ```
315 #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
316 #[doc = concat!("let m = ", $rot_op, ";")]
317 ///
318 #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
319 #[doc = concat!("assert_eq!(n.rotate_right(1024), n);")]
320 /// ```
321 #[stable(feature = "rust1", since = "1.0.0")]
322 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
323 #[must_use = "this returns the result of the operation, \
324 without modifying the original"]
325 #[inline(always)]
326 pub const fn rotate_right(self, n: u32) -> Self {
327 (self as $UnsignedT).rotate_right(n) as Self
328 }
329
330 /// Reverses the byte order of the integer.
331 ///
332 /// # Examples
333 ///
334 /// ```
335 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
336 ///
337 /// let m = n.swap_bytes();
338 ///
339 #[doc = concat!("assert_eq!(m, ", $swapped, ");")]
340 /// ```
341 #[stable(feature = "rust1", since = "1.0.0")]
342 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
343 #[must_use = "this returns the result of the operation, \
344 without modifying the original"]
345 #[inline(always)]
346 pub const fn swap_bytes(self) -> Self {
347 (self as $UnsignedT).swap_bytes() as Self
348 }
349
350 /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
351 /// second least-significant bit becomes second most-significant bit, etc.
352 ///
353 /// # Examples
354 ///
355 /// ```
356 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
357 /// let m = n.reverse_bits();
358 ///
359 #[doc = concat!("assert_eq!(m, ", $reversed, ");")]
360 #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
361 /// ```
362 #[stable(feature = "reverse_bits", since = "1.37.0")]
363 #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
364 #[must_use = "this returns the result of the operation, \
365 without modifying the original"]
366 #[inline(always)]
367 pub const fn reverse_bits(self) -> Self {
368 (self as $UnsignedT).reverse_bits() as Self
369 }
370
371 /// Converts an integer from big endian to the target's endianness.
372 ///
373 /// On big endian this is a no-op. On little endian the bytes are swapped.
374 ///
375 /// See also [from_be_bytes()](Self::from_be_bytes).
376 ///
377 /// # Examples
378 ///
379 /// ```
380 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
381 ///
382 /// if cfg!(target_endian = "big") {
383 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
384 /// } else {
385 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
386 /// }
387 /// ```
388 #[stable(feature = "rust1", since = "1.0.0")]
389 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
390 #[must_use]
391 #[inline]
392 pub const fn from_be(x: Self) -> Self {
393 #[cfg(target_endian = "big")]
394 {
395 x
396 }
397 #[cfg(not(target_endian = "big"))]
398 {
399 x.swap_bytes()
400 }
401 }
402
403 /// Converts an integer from little endian to the target's endianness.
404 ///
405 /// On little endian this is a no-op. On big endian the bytes are swapped.
406 ///
407 /// See also [from_le_bytes()](Self::from_le_bytes).
408 ///
409 /// # Examples
410 ///
411 /// ```
412 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
413 ///
414 /// if cfg!(target_endian = "little") {
415 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
416 /// } else {
417 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
418 /// }
419 /// ```
420 #[stable(feature = "rust1", since = "1.0.0")]
421 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
422 #[must_use]
423 #[inline]
424 pub const fn from_le(x: Self) -> Self {
425 #[cfg(target_endian = "little")]
426 {
427 x
428 }
429 #[cfg(not(target_endian = "little"))]
430 {
431 x.swap_bytes()
432 }
433 }
434
435 /// Swaps bytes of `self` on little endian targets.
436 ///
437 /// On big endian this is a no-op.
438 ///
439 /// The returned value has the same type as `self`, and will be interpreted
440 /// as (a potentially different) value of a native-endian
441 #[doc = concat!("`", stringify!($SelfT), "`.")]
442 ///
443 /// See [`to_be_bytes()`](Self::to_be_bytes) for a type-safe alternative.
444 ///
445 /// # Examples
446 ///
447 /// ```
448 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
449 ///
450 /// if cfg!(target_endian = "big") {
451 /// assert_eq!(n.to_be(), n)
452 /// } else {
453 /// assert_eq!(n.to_be(), n.swap_bytes())
454 /// }
455 /// ```
456 #[stable(feature = "rust1", since = "1.0.0")]
457 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
458 #[must_use = "this returns the result of the operation, \
459 without modifying the original"]
460 #[inline]
461 pub const fn to_be(self) -> Self { // or not to be?
462 #[cfg(target_endian = "big")]
463 {
464 self
465 }
466 #[cfg(not(target_endian = "big"))]
467 {
468 self.swap_bytes()
469 }
470 }
471
472 /// Swaps bytes of `self` on big endian targets.
473 ///
474 /// On little endian this is a no-op.
475 ///
476 /// The returned value has the same type as `self`, and will be interpreted
477 /// as (a potentially different) value of a native-endian
478 #[doc = concat!("`", stringify!($SelfT), "`.")]
479 ///
480 /// See [`to_le_bytes()`](Self::to_le_bytes) for a type-safe alternative.
481 ///
482 /// # Examples
483 ///
484 /// ```
485 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
486 ///
487 /// if cfg!(target_endian = "little") {
488 /// assert_eq!(n.to_le(), n)
489 /// } else {
490 /// assert_eq!(n.to_le(), n.swap_bytes())
491 /// }
492 /// ```
493 #[stable(feature = "rust1", since = "1.0.0")]
494 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
495 #[must_use = "this returns the result of the operation, \
496 without modifying the original"]
497 #[inline]
498 pub const fn to_le(self) -> Self {
499 #[cfg(target_endian = "little")]
500 {
501 self
502 }
503 #[cfg(not(target_endian = "little"))]
504 {
505 self.swap_bytes()
506 }
507 }
508
509 /// Checked integer addition. Computes `self + rhs`, returning `None`
510 /// if overflow occurred.
511 ///
512 /// # Examples
513 ///
514 /// ```
515 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), Some(", stringify!($SelfT), "::MAX - 1));")]
516 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
517 /// ```
518 #[stable(feature = "rust1", since = "1.0.0")]
519 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
520 #[must_use = "this returns the result of the operation, \
521 without modifying the original"]
522 #[inline]
523 pub const fn checked_add(self, rhs: Self) -> Option<Self> {
524 let (a, b) = self.overflowing_add(rhs);
525 if intrinsics::unlikely(b) { None } else { Some(a) }
526 }
527
528 /// Strict integer addition. Computes `self + rhs`, panicking
529 /// if overflow occurred.
530 ///
531 /// # Panics
532 ///
533 /// ## Overflow behavior
534 ///
535 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
536 ///
537 /// # Examples
538 ///
539 /// ```
540 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
541 /// ```
542 ///
543 /// The following panics because of overflow:
544 ///
545 /// ```should_panic
546 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
547 /// ```
548 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
549 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
550 #[must_use = "this returns the result of the operation, \
551 without modifying the original"]
552 #[inline]
553 #[track_caller]
554 pub const fn strict_add(self, rhs: Self) -> Self {
555 let (a, b) = self.overflowing_add(rhs);
556 if b { overflow_panic::add() } else { a }
557 }
558
559 /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
560 /// cannot occur.
561 ///
562 /// Calling `x.unchecked_add(y)` is semantically equivalent to calling
563 /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
564 ///
565 /// If you're just trying to avoid the panic in debug mode, then **do not**
566 /// use this. Instead, you're looking for [`wrapping_add`].
567 ///
568 /// # Safety
569 ///
570 /// This results in undefined behavior when
571 #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
572 /// i.e. when [`checked_add`] would return `None`.
573 ///
574 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
575 #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
576 #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
577 #[stable(feature = "unchecked_math", since = "1.79.0")]
578 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
579 #[must_use = "this returns the result of the operation, \
580 without modifying the original"]
581 #[inline(always)]
582 #[track_caller]
583 pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
584 assert_unsafe_precondition!(
585 check_language_ub,
586 concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
587 (
588 lhs: $SelfT = self,
589 rhs: $SelfT = rhs,
590 ) => !lhs.overflowing_add(rhs).1,
591 );
592
593 // SAFETY: this is guaranteed to be safe by the caller.
594 unsafe {
595 intrinsics::unchecked_add(self, rhs)
596 }
597 }
598
599 /// Checked addition with an unsigned integer. Computes `self + rhs`,
600 /// returning `None` if overflow occurred.
601 ///
602 /// # Examples
603 ///
604 /// ```
605 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_unsigned(2), Some(3));")]
606 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_unsigned(3), None);")]
607 /// ```
608 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
609 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
610 #[must_use = "this returns the result of the operation, \
611 without modifying the original"]
612 #[inline]
613 pub const fn checked_add_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
614 let (a, b) = self.overflowing_add_unsigned(rhs);
615 if intrinsics::unlikely(b) { None } else { Some(a) }
616 }
617
618 /// Strict addition with an unsigned integer. Computes `self + rhs`,
619 /// panicking if overflow occurred.
620 ///
621 /// # Panics
622 ///
623 /// ## Overflow behavior
624 ///
625 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
626 ///
627 /// # Examples
628 ///
629 /// ```
630 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_unsigned(2), 3);")]
631 /// ```
632 ///
633 /// The following panics because of overflow:
634 ///
635 /// ```should_panic
636 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_unsigned(3);")]
637 /// ```
638 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
639 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
640 #[must_use = "this returns the result of the operation, \
641 without modifying the original"]
642 #[inline]
643 #[track_caller]
644 pub const fn strict_add_unsigned(self, rhs: $UnsignedT) -> Self {
645 let (a, b) = self.overflowing_add_unsigned(rhs);
646 if b { overflow_panic::add() } else { a }
647 }
648
649 /// Checked integer subtraction. Computes `self - rhs`, returning `None` if
650 /// overflow occurred.
651 ///
652 /// # Examples
653 ///
654 /// ```
655 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(1), Some(", stringify!($SelfT), "::MIN + 1));")]
656 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(3), None);")]
657 /// ```
658 #[stable(feature = "rust1", since = "1.0.0")]
659 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
660 #[must_use = "this returns the result of the operation, \
661 without modifying the original"]
662 #[inline]
663 pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
664 let (a, b) = self.overflowing_sub(rhs);
665 if intrinsics::unlikely(b) { None } else { Some(a) }
666 }
667
668 /// Strict integer subtraction. Computes `self - rhs`, panicking if
669 /// overflow occurred.
670 ///
671 /// # Panics
672 ///
673 /// ## Overflow behavior
674 ///
675 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
676 ///
677 /// # Examples
678 ///
679 /// ```
680 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).strict_sub(1), ", stringify!($SelfT), "::MIN + 1);")]
681 /// ```
682 ///
683 /// The following panics because of overflow:
684 ///
685 /// ```should_panic
686 #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub(3);")]
687 /// ```
688 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
689 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
690 #[must_use = "this returns the result of the operation, \
691 without modifying the original"]
692 #[inline]
693 #[track_caller]
694 pub const fn strict_sub(self, rhs: Self) -> Self {
695 let (a, b) = self.overflowing_sub(rhs);
696 if b { overflow_panic::sub() } else { a }
697 }
698
699 /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
700 /// cannot occur.
701 ///
702 /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
703 /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
704 ///
705 /// If you're just trying to avoid the panic in debug mode, then **do not**
706 /// use this. Instead, you're looking for [`wrapping_sub`].
707 ///
708 /// # Safety
709 ///
710 /// This results in undefined behavior when
711 #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
712 /// i.e. when [`checked_sub`] would return `None`.
713 ///
714 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
715 #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
716 #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
717 #[stable(feature = "unchecked_math", since = "1.79.0")]
718 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
719 #[must_use = "this returns the result of the operation, \
720 without modifying the original"]
721 #[inline(always)]
722 #[track_caller]
723 pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
724 assert_unsafe_precondition!(
725 check_language_ub,
726 concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
727 (
728 lhs: $SelfT = self,
729 rhs: $SelfT = rhs,
730 ) => !lhs.overflowing_sub(rhs).1,
731 );
732
733 // SAFETY: this is guaranteed to be safe by the caller.
734 unsafe {
735 intrinsics::unchecked_sub(self, rhs)
736 }
737 }
738
739 /// Checked subtraction with an unsigned integer. Computes `self - rhs`,
740 /// returning `None` if overflow occurred.
741 ///
742 /// # Examples
743 ///
744 /// ```
745 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_unsigned(2), Some(-1));")]
746 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub_unsigned(3), None);")]
747 /// ```
748 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
749 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
750 #[must_use = "this returns the result of the operation, \
751 without modifying the original"]
752 #[inline]
753 pub const fn checked_sub_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
754 let (a, b) = self.overflowing_sub_unsigned(rhs);
755 if intrinsics::unlikely(b) { None } else { Some(a) }
756 }
757
758 /// Strict subtraction with an unsigned integer. Computes `self - rhs`,
759 /// panicking if overflow occurred.
760 ///
761 /// # Panics
762 ///
763 /// ## Overflow behavior
764 ///
765 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
766 ///
767 /// # Examples
768 ///
769 /// ```
770 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub_unsigned(2), -1);")]
771 /// ```
772 ///
773 /// The following panics because of overflow:
774 ///
775 /// ```should_panic
776 #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub_unsigned(3);")]
777 /// ```
778 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
779 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
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_sub_unsigned(self, rhs: $UnsignedT) -> Self {
785 let (a, b) = self.overflowing_sub_unsigned(rhs);
786 if b { overflow_panic::sub() } else { a }
787 }
788
789 /// Checked integer multiplication. Computes `self * rhs`, returning `None` if
790 /// overflow occurred.
791 ///
792 /// # Examples
793 ///
794 /// ```
795 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(1), Some(", stringify!($SelfT), "::MAX));")]
796 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
797 /// ```
798 #[stable(feature = "rust1", since = "1.0.0")]
799 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
800 #[must_use = "this returns the result of the operation, \
801 without modifying the original"]
802 #[inline]
803 pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
804 let (a, b) = self.overflowing_mul(rhs);
805 if intrinsics::unlikely(b) { None } else { Some(a) }
806 }
807
808 /// Strict integer multiplication. Computes `self * rhs`, panicking if
809 /// overflow occurred.
810 ///
811 /// # Panics
812 ///
813 /// ## Overflow behavior
814 ///
815 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
816 ///
817 /// # Examples
818 ///
819 /// ```
820 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.strict_mul(1), ", stringify!($SelfT), "::MAX);")]
821 /// ```
822 ///
823 /// The following panics because of overflow:
824 ///
825 /// ``` should_panic
826 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
827 /// ```
828 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
829 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
830 #[must_use = "this returns the result of the operation, \
831 without modifying the original"]
832 #[inline]
833 #[track_caller]
834 pub const fn strict_mul(self, rhs: Self) -> Self {
835 let (a, b) = self.overflowing_mul(rhs);
836 if b { overflow_panic::mul() } else { a }
837 }
838
839 /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
840 /// cannot occur.
841 ///
842 /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
843 /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
844 ///
845 /// If you're just trying to avoid the panic in debug mode, then **do not**
846 /// use this. Instead, you're looking for [`wrapping_mul`].
847 ///
848 /// # Safety
849 ///
850 /// This results in undefined behavior when
851 #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
852 /// i.e. when [`checked_mul`] would return `None`.
853 ///
854 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
855 #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
856 #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
857 #[stable(feature = "unchecked_math", since = "1.79.0")]
858 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
859 #[must_use = "this returns the result of the operation, \
860 without modifying the original"]
861 #[inline(always)]
862 #[track_caller]
863 pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
864 assert_unsafe_precondition!(
865 check_language_ub,
866 concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
867 (
868 lhs: $SelfT = self,
869 rhs: $SelfT = rhs,
870 ) => !lhs.overflowing_mul(rhs).1,
871 );
872
873 // SAFETY: this is guaranteed to be safe by the caller.
874 unsafe {
875 intrinsics::unchecked_mul(self, rhs)
876 }
877 }
878
879 /// Checked integer division. Computes `self / rhs`, returning `None` if `rhs == 0`
880 /// or the division results in overflow.
881 ///
882 /// # Examples
883 ///
884 /// ```
885 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div(-1), Some(", stringify!($Max), "));")]
886 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div(-1), None);")]
887 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div(0), None);")]
888 /// ```
889 #[stable(feature = "rust1", since = "1.0.0")]
890 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
891 #[must_use = "this returns the result of the operation, \
892 without modifying the original"]
893 #[inline]
894 pub const fn checked_div(self, rhs: Self) -> Option<Self> {
895 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
896 None
897 } else {
898 // SAFETY: div by zero and by INT_MIN have been checked above
899 Some(unsafe { intrinsics::unchecked_div(self, rhs) })
900 }
901 }
902
903 /// Strict integer division. Computes `self / rhs`, panicking
904 /// if overflow occurred.
905 ///
906 /// # Panics
907 ///
908 /// This function will panic if `rhs` is zero.
909 ///
910 /// ## Overflow behavior
911 ///
912 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
913 ///
914 /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
915 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
916 /// that is too large to represent in the type.
917 ///
918 /// # Examples
919 ///
920 /// ```
921 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).strict_div(-1), ", stringify!($Max), ");")]
922 /// ```
923 ///
924 /// The following panics because of overflow:
925 ///
926 /// ```should_panic
927 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_div(-1);")]
928 /// ```
929 ///
930 /// The following panics because of division by zero:
931 ///
932 /// ```should_panic
933 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
934 /// ```
935 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
936 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
937 #[must_use = "this returns the result of the operation, \
938 without modifying the original"]
939 #[inline]
940 #[track_caller]
941 pub const fn strict_div(self, rhs: Self) -> Self {
942 let (a, b) = self.overflowing_div(rhs);
943 if b { overflow_panic::div() } else { a }
944 }
945
946 /// Checked Euclidean division. Computes `self.div_euclid(rhs)`,
947 /// returning `None` if `rhs == 0` or the division results in overflow.
948 ///
949 /// # Examples
950 ///
951 /// ```
952 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div_euclid(-1), Some(", stringify!($Max), "));")]
953 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div_euclid(-1), None);")]
954 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div_euclid(0), None);")]
955 /// ```
956 #[stable(feature = "euclidean_division", since = "1.38.0")]
957 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
958 #[must_use = "this returns the result of the operation, \
959 without modifying the original"]
960 #[inline]
961 pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
962 // Using `&` helps LLVM see that it is the same check made in division.
963 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
964 None
965 } else {
966 Some(self.div_euclid(rhs))
967 }
968 }
969
970 /// Strict Euclidean division. Computes `self.div_euclid(rhs)`, panicking
971 /// if overflow occurred.
972 ///
973 /// # Panics
974 ///
975 /// This function will panic if `rhs` is zero.
976 ///
977 /// ## Overflow behavior
978 ///
979 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
980 ///
981 /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
982 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
983 /// that is too large to represent in the type.
984 ///
985 /// # Examples
986 ///
987 /// ```
988 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).strict_div_euclid(-1), ", stringify!($Max), ");")]
989 /// ```
990 ///
991 /// The following panics because of overflow:
992 ///
993 /// ```should_panic
994 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_div_euclid(-1);")]
995 /// ```
996 ///
997 /// The following panics because of division by zero:
998 ///
999 /// ```should_panic
1000 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
1001 /// ```
1002 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1003 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1004 #[must_use = "this returns the result of the operation, \
1005 without modifying the original"]
1006 #[inline]
1007 #[track_caller]
1008 pub const fn strict_div_euclid(self, rhs: Self) -> Self {
1009 let (a, b) = self.overflowing_div_euclid(rhs);
1010 if b { overflow_panic::div() } else { a }
1011 }
1012
1013 /// Checked integer division without remainder. Computes `self / rhs`,
1014 /// returning `None` if `rhs == 0`, the division results in overflow,
1015 /// or `self % rhs != 0`.
1016 ///
1017 /// # Examples
1018 ///
1019 /// ```
1020 /// #![feature(exact_div)]
1021 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div_exact(-1), Some(", stringify!($Max), "));")]
1022 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").checked_div_exact(2), None);")]
1023 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div_exact(-1), None);")]
1024 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div_exact(0), None);")]
1025 /// ```
1026 #[unstable(
1027 feature = "exact_div",
1028 issue = "139911",
1029 )]
1030 #[must_use = "this returns the result of the operation, \
1031 without modifying the original"]
1032 #[inline]
1033 pub const fn checked_div_exact(self, rhs: Self) -> Option<Self> {
1034 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
1035 None
1036 } else {
1037 // SAFETY: division by zero and overflow are checked above
1038 unsafe {
1039 if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) {
1040 None
1041 } else {
1042 Some(intrinsics::exact_div(self, rhs))
1043 }
1044 }
1045 }
1046 }
1047
1048 /// Integer division without remainder. Computes `self / rhs`, returning `None` if `self % rhs != 0`.
1049 ///
1050 /// # Panics
1051 ///
1052 /// This function will panic if `rhs == 0`.
1053 ///
1054 /// ## Overflow behavior
1055 ///
1056 /// On overflow, this function will panic if overflow checks are enabled (default in debug
1057 /// mode) and wrap if overflow checks are disabled (default in release mode).
1058 ///
1059 /// # Examples
1060 ///
1061 /// ```
1062 /// #![feature(exact_div)]
1063 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(2), Some(32));")]
1064 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(32), Some(2));")]
1065 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).div_exact(-1), Some(", stringify!($Max), "));")]
1066 #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".div_exact(2), None);")]
1067 /// ```
1068 /// ```should_panic
1069 /// #![feature(exact_div)]
1070 #[doc = concat!("let _ = 64", stringify!($SelfT),".div_exact(0);")]
1071 /// ```
1072 /// ```should_panic
1073 /// #![feature(exact_div)]
1074 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.div_exact(-1);")]
1075 /// ```
1076 #[unstable(
1077 feature = "exact_div",
1078 issue = "139911",
1079 )]
1080 #[must_use = "this returns the result of the operation, \
1081 without modifying the original"]
1082 #[inline]
1083 #[rustc_inherit_overflow_checks]
1084 pub const fn div_exact(self, rhs: Self) -> Option<Self> {
1085 if self % rhs != 0 {
1086 None
1087 } else {
1088 Some(self / rhs)
1089 }
1090 }
1091
1092 /// Unchecked integer division without remainder. Computes `self / rhs`.
1093 ///
1094 /// # Safety
1095 ///
1096 /// This results in undefined behavior when `rhs == 0`, `self % rhs != 0`, or
1097 #[doc = concat!("`self == ", stringify!($SelfT), "::MIN && rhs == -1`,")]
1098 /// i.e. when [`checked_div_exact`](Self::checked_div_exact) would return `None`.
1099 #[unstable(
1100 feature = "exact_div",
1101 issue = "139911",
1102 )]
1103 #[must_use = "this returns the result of the operation, \
1104 without modifying the original"]
1105 #[inline]
1106 pub const unsafe fn unchecked_div_exact(self, rhs: Self) -> Self {
1107 assert_unsafe_precondition!(
1108 check_language_ub,
1109 concat!(stringify!($SelfT), "::unchecked_div_exact cannot overflow, divide by zero, or leave a remainder"),
1110 (
1111 lhs: $SelfT = self,
1112 rhs: $SelfT = rhs,
1113 ) => rhs > 0 && lhs % rhs == 0 && (lhs != <$SelfT>::MIN || rhs != -1),
1114 );
1115 // SAFETY: Same precondition
1116 unsafe { intrinsics::exact_div(self, rhs) }
1117 }
1118
1119 /// Checked integer remainder. Computes `self % rhs`, returning `None` if
1120 /// `rhs == 0` or the division results in overflow.
1121 ///
1122 /// # Examples
1123 ///
1124 /// ```
1125 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
1126 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
1127 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_rem(-1), None);")]
1128 /// ```
1129 #[stable(feature = "wrapping", since = "1.7.0")]
1130 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1131 #[must_use = "this returns the result of the operation, \
1132 without modifying the original"]
1133 #[inline]
1134 pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
1135 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
1136 None
1137 } else {
1138 // SAFETY: div by zero and by INT_MIN have been checked above
1139 Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
1140 }
1141 }
1142
1143 /// Strict integer remainder. Computes `self % rhs`, panicking if
1144 /// the division results in overflow.
1145 ///
1146 /// # Panics
1147 ///
1148 /// This function will panic if `rhs` is zero.
1149 ///
1150 /// ## Overflow behavior
1151 ///
1152 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1153 ///
1154 /// The only case where such an overflow can occur is `x % y` for `MIN / -1` on a
1155 /// signed type (where `MIN` is the negative minimal value), which is invalid due to implementation artifacts.
1156 ///
1157 /// # Examples
1158 ///
1159 /// ```
1160 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_rem(2), 1);")]
1161 /// ```
1162 ///
1163 /// The following panics because of division by zero:
1164 ///
1165 /// ```should_panic
1166 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
1167 /// ```
1168 ///
1169 /// The following panics because of overflow:
1170 ///
1171 /// ```should_panic
1172 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem(-1);")]
1173 /// ```
1174 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1175 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1176 #[must_use = "this returns the result of the operation, \
1177 without modifying the original"]
1178 #[inline]
1179 #[track_caller]
1180 pub const fn strict_rem(self, rhs: Self) -> Self {
1181 let (a, b) = self.overflowing_rem(rhs);
1182 if b { overflow_panic::rem() } else { a }
1183 }
1184
1185 /// Checked Euclidean remainder. Computes `self.rem_euclid(rhs)`, returning `None`
1186 /// if `rhs == 0` or the division results in overflow.
1187 ///
1188 /// # Examples
1189 ///
1190 /// ```
1191 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
1192 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
1193 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_rem_euclid(-1), None);")]
1194 /// ```
1195 #[stable(feature = "euclidean_division", since = "1.38.0")]
1196 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1197 #[must_use = "this returns the result of the operation, \
1198 without modifying the original"]
1199 #[inline]
1200 pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
1201 // Using `&` helps LLVM see that it is the same check made in division.
1202 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
1203 None
1204 } else {
1205 Some(self.rem_euclid(rhs))
1206 }
1207 }
1208
1209 /// Strict Euclidean remainder. Computes `self.rem_euclid(rhs)`, panicking if
1210 /// the division results in overflow.
1211 ///
1212 /// # Panics
1213 ///
1214 /// This function will panic if `rhs` is zero.
1215 ///
1216 /// ## Overflow behavior
1217 ///
1218 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1219 ///
1220 /// The only case where such an overflow can occur is `x % y` for `MIN / -1` on a
1221 /// signed type (where `MIN` is the negative minimal value), which is invalid due to implementation artifacts.
1222 ///
1223 /// # Examples
1224 ///
1225 /// ```
1226 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_rem_euclid(2), 1);")]
1227 /// ```
1228 ///
1229 /// The following panics because of division by zero:
1230 ///
1231 /// ```should_panic
1232 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
1233 /// ```
1234 ///
1235 /// The following panics because of overflow:
1236 ///
1237 /// ```should_panic
1238 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem_euclid(-1);")]
1239 /// ```
1240 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1241 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1242 #[must_use = "this returns the result of the operation, \
1243 without modifying the original"]
1244 #[inline]
1245 #[track_caller]
1246 pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
1247 let (a, b) = self.overflowing_rem_euclid(rhs);
1248 if b { overflow_panic::rem() } else { a }
1249 }
1250
1251 /// Checked negation. Computes `-self`, returning `None` if `self == MIN`.
1252 ///
1253 /// # Examples
1254 ///
1255 /// ```
1256 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_neg(), Some(-5));")]
1257 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_neg(), None);")]
1258 /// ```
1259 #[stable(feature = "wrapping", since = "1.7.0")]
1260 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1261 #[must_use = "this returns the result of the operation, \
1262 without modifying the original"]
1263 #[inline]
1264 pub const fn checked_neg(self) -> Option<Self> {
1265 let (a, b) = self.overflowing_neg();
1266 if intrinsics::unlikely(b) { None } else { Some(a) }
1267 }
1268
1269 /// Unchecked negation. Computes `-self`, assuming overflow cannot occur.
1270 ///
1271 /// # Safety
1272 ///
1273 /// This results in undefined behavior when
1274 #[doc = concat!("`self == ", stringify!($SelfT), "::MIN`,")]
1275 /// i.e. when [`checked_neg`] would return `None`.
1276 ///
1277 #[doc = concat!("[`checked_neg`]: ", stringify!($SelfT), "::checked_neg")]
1278 #[stable(feature = "unchecked_neg", since = "CURRENT_RUSTC_VERSION")]
1279 #[rustc_const_stable(feature = "unchecked_neg", since = "CURRENT_RUSTC_VERSION")]
1280 #[must_use = "this returns the result of the operation, \
1281 without modifying the original"]
1282 #[inline(always)]
1283 #[track_caller]
1284 pub const unsafe fn unchecked_neg(self) -> Self {
1285 assert_unsafe_precondition!(
1286 check_language_ub,
1287 concat!(stringify!($SelfT), "::unchecked_neg cannot overflow"),
1288 (
1289 lhs: $SelfT = self,
1290 ) => !lhs.overflowing_neg().1,
1291 );
1292
1293 // SAFETY: this is guaranteed to be safe by the caller.
1294 unsafe {
1295 intrinsics::unchecked_sub(0, self)
1296 }
1297 }
1298
1299 /// Strict negation. Computes `-self`, panicking if `self == MIN`.
1300 ///
1301 /// # Panics
1302 ///
1303 /// ## Overflow behavior
1304 ///
1305 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1306 ///
1307 /// # Examples
1308 ///
1309 /// ```
1310 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_neg(), -5);")]
1311 /// ```
1312 ///
1313 /// The following panics because of overflow:
1314 ///
1315 /// ```should_panic
1316 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_neg();")]
1317 /// ```
1318 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1319 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1320 #[must_use = "this returns the result of the operation, \
1321 without modifying the original"]
1322 #[inline]
1323 #[track_caller]
1324 pub const fn strict_neg(self) -> Self {
1325 let (a, b) = self.overflowing_neg();
1326 if b { overflow_panic::neg() } else { a }
1327 }
1328
1329 /// Checked shift left. Computes `self << rhs`, returning `None` if `rhs` is larger
1330 /// than or equal to the number of bits in `self`.
1331 ///
1332 /// # Examples
1333 ///
1334 /// ```
1335 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
1336 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(129), None);")]
1337 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
1338 /// ```
1339 #[stable(feature = "wrapping", since = "1.7.0")]
1340 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1341 #[must_use = "this returns the result of the operation, \
1342 without modifying the original"]
1343 #[inline]
1344 pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
1345 // Not using overflowing_shl as that's a wrapping shift
1346 if rhs < Self::BITS {
1347 // SAFETY: just checked the RHS is in-range
1348 Some(unsafe { self.unchecked_shl(rhs) })
1349 } else {
1350 None
1351 }
1352 }
1353
1354 /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
1355 /// than or equal to the number of bits in `self`.
1356 ///
1357 /// # Panics
1358 ///
1359 /// ## Overflow behavior
1360 ///
1361 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1362 ///
1363 /// # Examples
1364 ///
1365 /// ```
1366 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
1367 /// ```
1368 ///
1369 /// The following panics because of overflow:
1370 ///
1371 /// ```should_panic
1372 #[doc = concat!("let _ = 0x1", stringify!($SelfT), ".strict_shl(129);")]
1373 /// ```
1374 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1375 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1376 #[must_use = "this returns the result of the operation, \
1377 without modifying the original"]
1378 #[inline]
1379 #[track_caller]
1380 pub const fn strict_shl(self, rhs: u32) -> Self {
1381 let (a, b) = self.overflowing_shl(rhs);
1382 if b { overflow_panic::shl() } else { a }
1383 }
1384
1385 /// Unchecked shift left. Computes `self << rhs`, assuming that
1386 /// `rhs` is less than the number of bits in `self`.
1387 ///
1388 /// # Safety
1389 ///
1390 /// This results in undefined behavior if `rhs` is larger than
1391 /// or equal to the number of bits in `self`,
1392 /// i.e. when [`checked_shl`] would return `None`.
1393 ///
1394 #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
1395 #[stable(feature = "unchecked_shifts", since = "CURRENT_RUSTC_VERSION")]
1396 #[rustc_const_stable(feature = "unchecked_shifts", since = "CURRENT_RUSTC_VERSION")]
1397 #[must_use = "this returns the result of the operation, \
1398 without modifying the original"]
1399 #[inline(always)]
1400 #[track_caller]
1401 pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
1402 assert_unsafe_precondition!(
1403 check_language_ub,
1404 concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
1405 (
1406 rhs: u32 = rhs,
1407 ) => rhs < <$ActualT>::BITS,
1408 );
1409
1410 // SAFETY: this is guaranteed to be safe by the caller.
1411 unsafe {
1412 intrinsics::unchecked_shl(self, rhs)
1413 }
1414 }
1415
1416 /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`.
1417 ///
1418 /// If `rhs` is larger or equal to the number of bits in `self`,
1419 /// the entire value is shifted out, and `0` is returned.
1420 ///
1421 /// # Examples
1422 ///
1423 /// ```
1424 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
1425 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(129), 0);")]
1426 /// ```
1427 #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1428 #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1429 #[must_use = "this returns the result of the operation, \
1430 without modifying the original"]
1431 #[inline]
1432 pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
1433 if rhs < Self::BITS {
1434 // SAFETY:
1435 // rhs is just checked to be in-range above
1436 unsafe { self.unchecked_shl(rhs) }
1437 } else {
1438 0
1439 }
1440 }
1441
1442 /// Exact shift left. Computes `self << rhs` as long as it can be reversed losslessly.
1443 ///
1444 /// Returns `None` if any bits that would be shifted out differ from the resulting sign bit
1445 /// or if `rhs` >=
1446 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1447 /// Otherwise, returns `Some(self << rhs)`.
1448 ///
1449 /// # Examples
1450 ///
1451 /// ```
1452 /// #![feature(exact_bitshifts)]
1453 ///
1454 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(4), Some(0x10));")]
1455 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(", stringify!($SelfT), "::BITS - 2), Some(1 << ", stringify!($SelfT), "::BITS - 2));")]
1456 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(", stringify!($SelfT), "::BITS - 1), None);")]
1457 #[doc = concat!("assert_eq!((-0x2", stringify!($SelfT), ").shl_exact(", stringify!($SelfT), "::BITS - 2), Some(-0x2 << ", stringify!($SelfT), "::BITS - 2));")]
1458 #[doc = concat!("assert_eq!((-0x2", stringify!($SelfT), ").shl_exact(", stringify!($SelfT), "::BITS - 1), None);")]
1459 /// ```
1460 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1461 #[must_use = "this returns the result of the operation, \
1462 without modifying the original"]
1463 #[inline]
1464 pub const fn shl_exact(self, rhs: u32) -> Option<$SelfT> {
1465 if rhs < self.leading_zeros() || rhs < self.leading_ones() {
1466 // SAFETY: rhs is checked above
1467 Some(unsafe { self.unchecked_shl(rhs) })
1468 } else {
1469 None
1470 }
1471 }
1472
1473 /// Unchecked exact shift left. Computes `self << rhs`, assuming the operation can be
1474 /// losslessly reversed and `rhs` cannot be larger than
1475 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1476 ///
1477 /// # Safety
1478 ///
1479 /// This results in undefined behavior when `rhs >= self.leading_zeros() && rhs >=
1480 /// self.leading_ones()` i.e. when
1481 #[doc = concat!("[`", stringify!($SelfT), "::shl_exact`]")]
1482 /// would return `None`.
1483 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1484 #[must_use = "this returns the result of the operation, \
1485 without modifying the original"]
1486 #[inline]
1487 pub const unsafe fn unchecked_shl_exact(self, rhs: u32) -> $SelfT {
1488 assert_unsafe_precondition!(
1489 check_library_ub,
1490 concat!(stringify!($SelfT), "::unchecked_shl_exact cannot shift out bits that would change the value of the first bit"),
1491 (
1492 zeros: u32 = self.leading_zeros(),
1493 ones: u32 = self.leading_ones(),
1494 rhs: u32 = rhs,
1495 ) => rhs < zeros || rhs < ones,
1496 );
1497
1498 // SAFETY: this is guaranteed to be safe by the caller
1499 unsafe { self.unchecked_shl(rhs) }
1500 }
1501
1502 /// Checked shift right. Computes `self >> rhs`, returning `None` if `rhs` is
1503 /// larger than or equal to the number of bits in `self`.
1504 ///
1505 /// # Examples
1506 ///
1507 /// ```
1508 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
1509 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(128), None);")]
1510 /// ```
1511 #[stable(feature = "wrapping", since = "1.7.0")]
1512 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1513 #[must_use = "this returns the result of the operation, \
1514 without modifying the original"]
1515 #[inline]
1516 pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
1517 // Not using overflowing_shr as that's a wrapping shift
1518 if rhs < Self::BITS {
1519 // SAFETY: just checked the RHS is in-range
1520 Some(unsafe { self.unchecked_shr(rhs) })
1521 } else {
1522 None
1523 }
1524 }
1525
1526 /// Strict shift right. Computes `self >> rhs`, panicking if `rhs` is
1527 /// larger than or equal to the number of bits in `self`.
1528 ///
1529 /// # Panics
1530 ///
1531 /// ## Overflow behavior
1532 ///
1533 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1534 ///
1535 /// # Examples
1536 ///
1537 /// ```
1538 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
1539 /// ```
1540 ///
1541 /// The following panics because of overflow:
1542 ///
1543 /// ```should_panic
1544 #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(128);")]
1545 /// ```
1546 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1547 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1548 #[must_use = "this returns the result of the operation, \
1549 without modifying the original"]
1550 #[inline]
1551 #[track_caller]
1552 pub const fn strict_shr(self, rhs: u32) -> Self {
1553 let (a, b) = self.overflowing_shr(rhs);
1554 if b { overflow_panic::shr() } else { a }
1555 }
1556
1557 /// Unchecked shift right. Computes `self >> rhs`, assuming that
1558 /// `rhs` is less than the number of bits in `self`.
1559 ///
1560 /// # Safety
1561 ///
1562 /// This results in undefined behavior if `rhs` is larger than
1563 /// or equal to the number of bits in `self`,
1564 /// i.e. when [`checked_shr`] would return `None`.
1565 ///
1566 #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
1567 #[stable(feature = "unchecked_shifts", since = "CURRENT_RUSTC_VERSION")]
1568 #[rustc_const_stable(feature = "unchecked_shifts", since = "CURRENT_RUSTC_VERSION")]
1569 #[must_use = "this returns the result of the operation, \
1570 without modifying the original"]
1571 #[inline(always)]
1572 #[track_caller]
1573 pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
1574 assert_unsafe_precondition!(
1575 check_language_ub,
1576 concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
1577 (
1578 rhs: u32 = rhs,
1579 ) => rhs < <$ActualT>::BITS,
1580 );
1581
1582 // SAFETY: this is guaranteed to be safe by the caller.
1583 unsafe {
1584 intrinsics::unchecked_shr(self, rhs)
1585 }
1586 }
1587
1588 /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`.
1589 ///
1590 /// If `rhs` is larger or equal to the number of bits in `self`,
1591 /// the entire value is shifted out, which yields `0` for a positive number,
1592 /// and `-1` for a negative number.
1593 ///
1594 /// # Examples
1595 ///
1596 /// ```
1597 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
1598 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(129), 0);")]
1599 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.unbounded_shr(129), -1);")]
1600 /// ```
1601 #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1602 #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1603 #[must_use = "this returns the result of the operation, \
1604 without modifying the original"]
1605 #[inline]
1606 pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
1607 if rhs < Self::BITS {
1608 // SAFETY:
1609 // rhs is just checked to be in-range above
1610 unsafe { self.unchecked_shr(rhs) }
1611 } else {
1612 // A shift by `Self::BITS-1` suffices for signed integers, because the sign bit is copied for each of the shifted bits.
1613
1614 // SAFETY:
1615 // `Self::BITS-1` is guaranteed to be less than `Self::BITS`
1616 unsafe { self.unchecked_shr(Self::BITS - 1) }
1617 }
1618 }
1619
1620 /// Exact shift right. Computes `self >> rhs` as long as it can be reversed losslessly.
1621 ///
1622 /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
1623 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1624 /// Otherwise, returns `Some(self >> rhs)`.
1625 ///
1626 /// # Examples
1627 ///
1628 /// ```
1629 /// #![feature(exact_bitshifts)]
1630 ///
1631 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(4), Some(0x1));")]
1632 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(5), None);")]
1633 /// ```
1634 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1635 #[must_use = "this returns the result of the operation, \
1636 without modifying the original"]
1637 #[inline]
1638 pub const fn shr_exact(self, rhs: u32) -> Option<$SelfT> {
1639 if rhs <= self.trailing_zeros() && rhs < <$SelfT>::BITS {
1640 // SAFETY: rhs is checked above
1641 Some(unsafe { self.unchecked_shr(rhs) })
1642 } else {
1643 None
1644 }
1645 }
1646
1647 /// Unchecked exact shift right. Computes `self >> rhs`, assuming the operation can be
1648 /// losslessly reversed and `rhs` cannot be larger than
1649 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1650 ///
1651 /// # Safety
1652 ///
1653 /// This results in undefined behavior when `rhs > self.trailing_zeros() || rhs >=
1654 #[doc = concat!(stringify!($SelfT), "::BITS`")]
1655 /// i.e. when
1656 #[doc = concat!("[`", stringify!($SelfT), "::shr_exact`]")]
1657 /// would return `None`.
1658 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1659 #[must_use = "this returns the result of the operation, \
1660 without modifying the original"]
1661 #[inline]
1662 pub const unsafe fn unchecked_shr_exact(self, rhs: u32) -> $SelfT {
1663 assert_unsafe_precondition!(
1664 check_library_ub,
1665 concat!(stringify!($SelfT), "::unchecked_shr_exact cannot shift out non-zero bits"),
1666 (
1667 zeros: u32 = self.trailing_zeros(),
1668 bits: u32 = <$SelfT>::BITS,
1669 rhs: u32 = rhs,
1670 ) => rhs <= zeros && rhs < bits,
1671 );
1672
1673 // SAFETY: this is guaranteed to be safe by the caller
1674 unsafe { self.unchecked_shr(rhs) }
1675 }
1676
1677 /// Checked absolute value. Computes `self.abs()`, returning `None` if
1678 /// `self == MIN`.
1679 ///
1680 /// # Examples
1681 ///
1682 /// ```
1683 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").checked_abs(), Some(5));")]
1684 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_abs(), None);")]
1685 /// ```
1686 #[stable(feature = "no_panic_abs", since = "1.13.0")]
1687 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1688 #[must_use = "this returns the result of the operation, \
1689 without modifying the original"]
1690 #[inline]
1691 pub const fn checked_abs(self) -> Option<Self> {
1692 if self.is_negative() {
1693 self.checked_neg()
1694 } else {
1695 Some(self)
1696 }
1697 }
1698
1699 /// Strict absolute value. Computes `self.abs()`, panicking if
1700 /// `self == MIN`.
1701 ///
1702 /// # Panics
1703 ///
1704 /// ## Overflow behavior
1705 ///
1706 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1707 ///
1708 /// # Examples
1709 ///
1710 /// ```
1711 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").strict_abs(), 5);")]
1712 /// ```
1713 ///
1714 /// The following panics because of overflow:
1715 ///
1716 /// ```should_panic
1717 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_abs();")]
1718 /// ```
1719 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1720 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1721 #[must_use = "this returns the result of the operation, \
1722 without modifying the original"]
1723 #[inline]
1724 #[track_caller]
1725 pub const fn strict_abs(self) -> Self {
1726 if self.is_negative() {
1727 self.strict_neg()
1728 } else {
1729 self
1730 }
1731 }
1732
1733 /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
1734 /// overflow occurred.
1735 ///
1736 /// # Examples
1737 ///
1738 /// ```
1739 #[doc = concat!("assert_eq!(8", stringify!($SelfT), ".checked_pow(2), Some(64));")]
1740 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".checked_pow(0), Some(1));")]
1741 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
1742 /// ```
1743
1744 #[stable(feature = "no_panic_pow", since = "1.34.0")]
1745 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
1746 #[must_use = "this returns the result of the operation, \
1747 without modifying the original"]
1748 #[inline]
1749 pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
1750 if exp == 0 {
1751 return Some(1);
1752 }
1753 let mut base = self;
1754 let mut acc: Self = 1;
1755
1756 loop {
1757 if (exp & 1) == 1 {
1758 acc = try_opt!(acc.checked_mul(base));
1759 // since exp!=0, finally the exp must be 1.
1760 if exp == 1 {
1761 return Some(acc);
1762 }
1763 }
1764 exp /= 2;
1765 base = try_opt!(base.checked_mul(base));
1766 }
1767 }
1768
1769 /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
1770 /// overflow occurred.
1771 ///
1772 /// # Panics
1773 ///
1774 /// ## Overflow behavior
1775 ///
1776 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1777 ///
1778 /// # Examples
1779 ///
1780 /// ```
1781 #[doc = concat!("assert_eq!(8", stringify!($SelfT), ".strict_pow(2), 64);")]
1782 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".strict_pow(0), 1);")]
1783 /// ```
1784 ///
1785 /// The following panics because of overflow:
1786 ///
1787 /// ```should_panic
1788 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
1789 /// ```
1790 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1791 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1792 #[must_use = "this returns the result of the operation, \
1793 without modifying the original"]
1794 #[inline]
1795 #[track_caller]
1796 pub const fn strict_pow(self, mut exp: u32) -> Self {
1797 if exp == 0 {
1798 return 1;
1799 }
1800 let mut base = self;
1801 let mut acc: Self = 1;
1802
1803 loop {
1804 if (exp & 1) == 1 {
1805 acc = acc.strict_mul(base);
1806 // since exp!=0, finally the exp must be 1.
1807 if exp == 1 {
1808 return acc;
1809 }
1810 }
1811 exp /= 2;
1812 base = base.strict_mul(base);
1813 }
1814 }
1815
1816 /// Returns the square root of the number, rounded down.
1817 ///
1818 /// Returns `None` if `self` is negative.
1819 ///
1820 /// # Examples
1821 ///
1822 /// ```
1823 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_isqrt(), Some(3));")]
1824 /// ```
1825 #[stable(feature = "isqrt", since = "1.84.0")]
1826 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
1827 #[must_use = "this returns the result of the operation, \
1828 without modifying the original"]
1829 #[inline]
1830 pub const fn checked_isqrt(self) -> Option<Self> {
1831 if self < 0 {
1832 None
1833 } else {
1834 // SAFETY: Input is nonnegative in this `else` branch.
1835 let result = unsafe {
1836 crate::num::int_sqrt::$ActualT(self as $ActualT) as $SelfT
1837 };
1838
1839 // Inform the optimizer what the range of outputs is. If
1840 // testing `core` crashes with no panic message and a
1841 // `num::int_sqrt::i*` test failed, it's because your edits
1842 // caused these assertions to become false.
1843 //
1844 // SAFETY: Integer square root is a monotonically nondecreasing
1845 // function, which means that increasing the input will never
1846 // cause the output to decrease. Thus, since the input for
1847 // nonnegative signed integers is bounded by
1848 // `[0, <$ActualT>::MAX]`, sqrt(n) will be bounded by
1849 // `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
1850 unsafe {
1851 // SAFETY: `<$ActualT>::MAX` is nonnegative.
1852 const MAX_RESULT: $SelfT = unsafe {
1853 crate::num::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT
1854 };
1855
1856 crate::hint::assert_unchecked(result >= 0);
1857 crate::hint::assert_unchecked(result <= MAX_RESULT);
1858 }
1859
1860 Some(result)
1861 }
1862 }
1863
1864 /// Saturating integer addition. Computes `self + rhs`, saturating at the numeric
1865 /// bounds instead of overflowing.
1866 ///
1867 /// # Examples
1868 ///
1869 /// ```
1870 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
1871 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(100), ", stringify!($SelfT), "::MAX);")]
1872 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_add(-1), ", stringify!($SelfT), "::MIN);")]
1873 /// ```
1874
1875 #[stable(feature = "rust1", since = "1.0.0")]
1876 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1877 #[must_use = "this returns the result of the operation, \
1878 without modifying the original"]
1879 #[inline(always)]
1880 pub const fn saturating_add(self, rhs: Self) -> Self {
1881 intrinsics::saturating_add(self, rhs)
1882 }
1883
1884 /// Saturating addition with an unsigned integer. Computes `self + rhs`,
1885 /// saturating at the numeric bounds instead of overflowing.
1886 ///
1887 /// # Examples
1888 ///
1889 /// ```
1890 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_unsigned(2), 3);")]
1891 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add_unsigned(100), ", stringify!($SelfT), "::MAX);")]
1892 /// ```
1893 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1894 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1895 #[must_use = "this returns the result of the operation, \
1896 without modifying the original"]
1897 #[inline]
1898 pub const fn saturating_add_unsigned(self, rhs: $UnsignedT) -> Self {
1899 // Overflow can only happen at the upper bound
1900 // We cannot use `unwrap_or` here because it is not `const`
1901 match self.checked_add_unsigned(rhs) {
1902 Some(x) => x,
1903 None => Self::MAX,
1904 }
1905 }
1906
1907 /// Saturating integer subtraction. Computes `self - rhs`, saturating at the
1908 /// numeric bounds instead of overflowing.
1909 ///
1910 /// # Examples
1911 ///
1912 /// ```
1913 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(127), -27);")]
1914 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub(100), ", stringify!($SelfT), "::MIN);")]
1915 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_sub(-1), ", stringify!($SelfT), "::MAX);")]
1916 /// ```
1917 #[stable(feature = "rust1", since = "1.0.0")]
1918 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1919 #[must_use = "this returns the result of the operation, \
1920 without modifying the original"]
1921 #[inline(always)]
1922 pub const fn saturating_sub(self, rhs: Self) -> Self {
1923 intrinsics::saturating_sub(self, rhs)
1924 }
1925
1926 /// Saturating subtraction with an unsigned integer. Computes `self - rhs`,
1927 /// saturating at the numeric bounds instead of overflowing.
1928 ///
1929 /// # Examples
1930 ///
1931 /// ```
1932 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub_unsigned(127), -27);")]
1933 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub_unsigned(100), ", stringify!($SelfT), "::MIN);")]
1934 /// ```
1935 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1936 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1937 #[must_use = "this returns the result of the operation, \
1938 without modifying the original"]
1939 #[inline]
1940 pub const fn saturating_sub_unsigned(self, rhs: $UnsignedT) -> Self {
1941 // Overflow can only happen at the lower bound
1942 // We cannot use `unwrap_or` here because it is not `const`
1943 match self.checked_sub_unsigned(rhs) {
1944 Some(x) => x,
1945 None => Self::MIN,
1946 }
1947 }
1948
1949 /// Saturating integer negation. Computes `-self`, returning `MAX` if `self == MIN`
1950 /// instead of overflowing.
1951 ///
1952 /// # Examples
1953 ///
1954 /// ```
1955 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_neg(), -100);")]
1956 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").saturating_neg(), 100);")]
1957 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_neg(), ", stringify!($SelfT), "::MAX);")]
1958 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_neg(), ", stringify!($SelfT), "::MIN + 1);")]
1959 /// ```
1960
1961 #[stable(feature = "saturating_neg", since = "1.45.0")]
1962 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1963 #[must_use = "this returns the result of the operation, \
1964 without modifying the original"]
1965 #[inline(always)]
1966 pub const fn saturating_neg(self) -> Self {
1967 intrinsics::saturating_sub(0, self)
1968 }
1969
1970 /// Saturating absolute value. Computes `self.abs()`, returning `MAX` if `self ==
1971 /// MIN` instead of overflowing.
1972 ///
1973 /// # Examples
1974 ///
1975 /// ```
1976 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_abs(), 100);")]
1977 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").saturating_abs(), 100);")]
1978 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_abs(), ", stringify!($SelfT), "::MAX);")]
1979 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).saturating_abs(), ", stringify!($SelfT), "::MAX);")]
1980 /// ```
1981
1982 #[stable(feature = "saturating_neg", since = "1.45.0")]
1983 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1984 #[must_use = "this returns the result of the operation, \
1985 without modifying the original"]
1986 #[inline]
1987 pub const fn saturating_abs(self) -> Self {
1988 if self.is_negative() {
1989 self.saturating_neg()
1990 } else {
1991 self
1992 }
1993 }
1994
1995 /// Saturating integer multiplication. Computes `self * rhs`, saturating at the
1996 /// numeric bounds instead of overflowing.
1997 ///
1998 /// # Examples
1999 ///
2000 /// ```
2001 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".saturating_mul(12), 120);")]
2002 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_mul(10), ", stringify!($SelfT), "::MAX);")]
2003 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_mul(10), ", stringify!($SelfT), "::MIN);")]
2004 /// ```
2005 #[stable(feature = "wrapping", since = "1.7.0")]
2006 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2007 #[must_use = "this returns the result of the operation, \
2008 without modifying the original"]
2009 #[inline]
2010 pub const fn saturating_mul(self, rhs: Self) -> Self {
2011 match self.checked_mul(rhs) {
2012 Some(x) => x,
2013 None => if (self < 0) == (rhs < 0) {
2014 Self::MAX
2015 } else {
2016 Self::MIN
2017 }
2018 }
2019 }
2020
2021 /// Saturating integer division. Computes `self / rhs`, saturating at the
2022 /// numeric bounds instead of overflowing.
2023 ///
2024 /// # Panics
2025 ///
2026 /// This function will panic if `rhs` is zero.
2027 ///
2028 /// # Examples
2029 ///
2030 /// ```
2031 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
2032 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_div(-1), ", stringify!($SelfT), "::MIN + 1);")]
2033 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_div(-1), ", stringify!($SelfT), "::MAX);")]
2034 ///
2035 /// ```
2036 #[stable(feature = "saturating_div", since = "1.58.0")]
2037 #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
2038 #[must_use = "this returns the result of the operation, \
2039 without modifying the original"]
2040 #[inline]
2041 pub const fn saturating_div(self, rhs: Self) -> Self {
2042 match self.overflowing_div(rhs) {
2043 (result, false) => result,
2044 (_result, true) => Self::MAX, // MIN / -1 is the only possible saturating overflow
2045 }
2046 }
2047
2048 /// Saturating integer exponentiation. Computes `self.pow(exp)`,
2049 /// saturating at the numeric bounds instead of overflowing.
2050 ///
2051 /// # Examples
2052 ///
2053 /// ```
2054 #[doc = concat!("assert_eq!((-4", stringify!($SelfT), ").saturating_pow(3), -64);")]
2055 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".saturating_pow(0), 1);")]
2056 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
2057 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(3), ", stringify!($SelfT), "::MIN);")]
2058 /// ```
2059 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2060 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2061 #[must_use = "this returns the result of the operation, \
2062 without modifying the original"]
2063 #[inline]
2064 pub const fn saturating_pow(self, exp: u32) -> Self {
2065 match self.checked_pow(exp) {
2066 Some(x) => x,
2067 None if self < 0 && exp % 2 == 1 => Self::MIN,
2068 None => Self::MAX,
2069 }
2070 }
2071
2072 /// Wrapping (modular) addition. Computes `self + rhs`, wrapping around at the
2073 /// boundary of the type.
2074 ///
2075 /// # Examples
2076 ///
2077 /// ```
2078 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add(27), 127);")]
2079 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add(2), ", stringify!($SelfT), "::MIN + 1);")]
2080 /// ```
2081 #[stable(feature = "rust1", since = "1.0.0")]
2082 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2083 #[must_use = "this returns the result of the operation, \
2084 without modifying the original"]
2085 #[inline(always)]
2086 pub const fn wrapping_add(self, rhs: Self) -> Self {
2087 intrinsics::wrapping_add(self, rhs)
2088 }
2089
2090 /// Wrapping (modular) addition with an unsigned integer. Computes
2091 /// `self + rhs`, wrapping around at the boundary of the type.
2092 ///
2093 /// # Examples
2094 ///
2095 /// ```
2096 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add_unsigned(27), 127);")]
2097 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add_unsigned(2), ", stringify!($SelfT), "::MIN + 1);")]
2098 /// ```
2099 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2100 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2101 #[must_use = "this returns the result of the operation, \
2102 without modifying the original"]
2103 #[inline(always)]
2104 pub const fn wrapping_add_unsigned(self, rhs: $UnsignedT) -> Self {
2105 self.wrapping_add(rhs as Self)
2106 }
2107
2108 /// Wrapping (modular) subtraction. Computes `self - rhs`, wrapping around at the
2109 /// boundary of the type.
2110 ///
2111 /// # Examples
2112 ///
2113 /// ```
2114 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub(127), -127);")]
2115 #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub(", stringify!($SelfT), "::MAX), ", stringify!($SelfT), "::MAX);")]
2116 /// ```
2117 #[stable(feature = "rust1", since = "1.0.0")]
2118 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2119 #[must_use = "this returns the result of the operation, \
2120 without modifying the original"]
2121 #[inline(always)]
2122 pub const fn wrapping_sub(self, rhs: Self) -> Self {
2123 intrinsics::wrapping_sub(self, rhs)
2124 }
2125
2126 /// Wrapping (modular) subtraction with an unsigned integer. Computes
2127 /// `self - rhs`, wrapping around at the boundary of the type.
2128 ///
2129 /// # Examples
2130 ///
2131 /// ```
2132 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub_unsigned(127), -127);")]
2133 #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub_unsigned(", stringify!($UnsignedT), "::MAX), -1);")]
2134 /// ```
2135 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2136 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2137 #[must_use = "this returns the result of the operation, \
2138 without modifying the original"]
2139 #[inline(always)]
2140 pub const fn wrapping_sub_unsigned(self, rhs: $UnsignedT) -> Self {
2141 self.wrapping_sub(rhs as Self)
2142 }
2143
2144 /// Wrapping (modular) multiplication. Computes `self * rhs`, wrapping around at
2145 /// the boundary of the type.
2146 ///
2147 /// # Examples
2148 ///
2149 /// ```
2150 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".wrapping_mul(12), 120);")]
2151 /// assert_eq!(11i8.wrapping_mul(12), -124);
2152 /// ```
2153 #[stable(feature = "rust1", since = "1.0.0")]
2154 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2155 #[must_use = "this returns the result of the operation, \
2156 without modifying the original"]
2157 #[inline(always)]
2158 pub const fn wrapping_mul(self, rhs: Self) -> Self {
2159 intrinsics::wrapping_mul(self, rhs)
2160 }
2161
2162 /// Wrapping (modular) division. Computes `self / rhs`, wrapping around at the
2163 /// boundary of the type.
2164 ///
2165 /// The only case where such wrapping can occur is when one divides `MIN / -1` on a signed type (where
2166 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
2167 /// that is too large to represent in the type. In such a case, this function returns `MIN` itself.
2168 ///
2169 /// # Panics
2170 ///
2171 /// This function will panic if `rhs` is zero.
2172 ///
2173 /// # Examples
2174 ///
2175 /// ```
2176 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
2177 /// assert_eq!((-128i8).wrapping_div(-1), -128);
2178 /// ```
2179 #[stable(feature = "num_wrapping", since = "1.2.0")]
2180 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2181 #[must_use = "this returns the result of the operation, \
2182 without modifying the original"]
2183 #[inline]
2184 pub const fn wrapping_div(self, rhs: Self) -> Self {
2185 self.overflowing_div(rhs).0
2186 }
2187
2188 /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`,
2189 /// wrapping around at the boundary of the type.
2190 ///
2191 /// Wrapping will only occur in `MIN / -1` on a signed type (where `MIN` is the negative minimal value
2192 /// for the type). This is equivalent to `-MIN`, a positive value that is too large to represent in the
2193 /// type. In this case, this method returns `MIN` itself.
2194 ///
2195 /// # Panics
2196 ///
2197 /// This function will panic if `rhs` is zero.
2198 ///
2199 /// # Examples
2200 ///
2201 /// ```
2202 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
2203 /// assert_eq!((-128i8).wrapping_div_euclid(-1), -128);
2204 /// ```
2205 #[stable(feature = "euclidean_division", since = "1.38.0")]
2206 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2207 #[must_use = "this returns the result of the operation, \
2208 without modifying the original"]
2209 #[inline]
2210 pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
2211 self.overflowing_div_euclid(rhs).0
2212 }
2213
2214 /// Wrapping (modular) remainder. Computes `self % rhs`, wrapping around at the
2215 /// boundary of the type.
2216 ///
2217 /// Such wrap-around never actually occurs mathematically; implementation artifacts make `x % y`
2218 /// invalid for `MIN / -1` on a signed type (where `MIN` is the negative minimal value). In such a case,
2219 /// this function returns `0`.
2220 ///
2221 /// # Panics
2222 ///
2223 /// This function will panic if `rhs` is zero.
2224 ///
2225 /// # Examples
2226 ///
2227 /// ```
2228 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
2229 /// assert_eq!((-128i8).wrapping_rem(-1), 0);
2230 /// ```
2231 #[stable(feature = "num_wrapping", since = "1.2.0")]
2232 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2233 #[must_use = "this returns the result of the operation, \
2234 without modifying the original"]
2235 #[inline]
2236 pub const fn wrapping_rem(self, rhs: Self) -> Self {
2237 self.overflowing_rem(rhs).0
2238 }
2239
2240 /// Wrapping Euclidean remainder. Computes `self.rem_euclid(rhs)`, wrapping around
2241 /// at the boundary of the type.
2242 ///
2243 /// Wrapping will only occur in `MIN % -1` on a signed type (where `MIN` is the negative minimal value
2244 /// for the type). In this case, this method returns 0.
2245 ///
2246 /// # Panics
2247 ///
2248 /// This function will panic if `rhs` is zero.
2249 ///
2250 /// # Examples
2251 ///
2252 /// ```
2253 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
2254 /// assert_eq!((-128i8).wrapping_rem_euclid(-1), 0);
2255 /// ```
2256 #[stable(feature = "euclidean_division", since = "1.38.0")]
2257 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2258 #[must_use = "this returns the result of the operation, \
2259 without modifying the original"]
2260 #[inline]
2261 pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
2262 self.overflowing_rem_euclid(rhs).0
2263 }
2264
2265 /// Wrapping (modular) negation. Computes `-self`, wrapping around at the boundary
2266 /// of the type.
2267 ///
2268 /// The only case where such wrapping can occur is when one negates `MIN` on a signed type (where `MIN`
2269 /// is the negative minimal value for the type); this is a positive value that is too large to represent
2270 /// in the type. In such a case, this function returns `MIN` itself.
2271 ///
2272 /// # Examples
2273 ///
2274 /// ```
2275 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_neg(), -100);")]
2276 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").wrapping_neg(), 100);")]
2277 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.wrapping_neg(), ", stringify!($SelfT), "::MIN);")]
2278 /// ```
2279 #[stable(feature = "num_wrapping", since = "1.2.0")]
2280 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2281 #[must_use = "this returns the result of the operation, \
2282 without modifying the original"]
2283 #[inline(always)]
2284 pub const fn wrapping_neg(self) -> Self {
2285 (0 as $SelfT).wrapping_sub(self)
2286 }
2287
2288 /// Panic-free bitwise shift-left; yields `self << mask(rhs)`, where `mask` removes
2289 /// any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type.
2290 ///
2291 /// Note that this is *not* the same as a rotate-left; the RHS of a wrapping shift-left is restricted to
2292 /// the range of the type, rather than the bits shifted out of the LHS being returned to the other end.
2293 /// The primitive integer types all implement a [`rotate_left`](Self::rotate_left) function,
2294 /// which may be what you want instead.
2295 ///
2296 /// # Examples
2297 ///
2298 /// ```
2299 #[doc = concat!("assert_eq!((-1", stringify!($SelfT), ").wrapping_shl(7), -128);")]
2300 #[doc = concat!("assert_eq!((-1", stringify!($SelfT), ").wrapping_shl(128), -1);")]
2301 /// ```
2302 #[stable(feature = "num_wrapping", since = "1.2.0")]
2303 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2304 #[must_use = "this returns the result of the operation, \
2305 without modifying the original"]
2306 #[inline(always)]
2307 pub const fn wrapping_shl(self, rhs: u32) -> Self {
2308 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2309 // out of bounds
2310 unsafe {
2311 self.unchecked_shl(rhs & (Self::BITS - 1))
2312 }
2313 }
2314
2315 /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`, where `mask`
2316 /// removes any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type.
2317 ///
2318 /// Note that this is *not* the same as a rotate-right; the RHS of a wrapping shift-right is restricted
2319 /// to the range of the type, rather than the bits shifted out of the LHS being returned to the other
2320 /// end. The primitive integer types all implement a [`rotate_right`](Self::rotate_right) function,
2321 /// which may be what you want instead.
2322 ///
2323 /// # Examples
2324 ///
2325 /// ```
2326 #[doc = concat!("assert_eq!((-128", stringify!($SelfT), ").wrapping_shr(7), -1);")]
2327 /// assert_eq!((-128i16).wrapping_shr(64), -128);
2328 /// ```
2329 #[stable(feature = "num_wrapping", since = "1.2.0")]
2330 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2331 #[must_use = "this returns the result of the operation, \
2332 without modifying the original"]
2333 #[inline(always)]
2334 pub const fn wrapping_shr(self, rhs: u32) -> Self {
2335 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2336 // out of bounds
2337 unsafe {
2338 self.unchecked_shr(rhs & (Self::BITS - 1))
2339 }
2340 }
2341
2342 /// Wrapping (modular) absolute value. Computes `self.abs()`, wrapping around at
2343 /// the boundary of the type.
2344 ///
2345 /// The only case where such wrapping can occur is when one takes the absolute value of the negative
2346 /// minimal value for the type; this is a positive value that is too large to represent in the type. In
2347 /// such a case, this function returns `MIN` itself.
2348 ///
2349 /// # Examples
2350 ///
2351 /// ```
2352 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_abs(), 100);")]
2353 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").wrapping_abs(), 100);")]
2354 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.wrapping_abs(), ", stringify!($SelfT), "::MIN);")]
2355 /// assert_eq!((-128i8).wrapping_abs() as u8, 128);
2356 /// ```
2357 #[stable(feature = "no_panic_abs", since = "1.13.0")]
2358 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2359 #[must_use = "this returns the result of the operation, \
2360 without modifying the original"]
2361 #[allow(unused_attributes)]
2362 #[inline]
2363 pub const fn wrapping_abs(self) -> Self {
2364 if self.is_negative() {
2365 self.wrapping_neg()
2366 } else {
2367 self
2368 }
2369 }
2370
2371 /// Computes the absolute value of `self` without any wrapping
2372 /// or panicking.
2373 ///
2374 ///
2375 /// # Examples
2376 ///
2377 /// ```
2378 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".unsigned_abs(), 100", stringify!($UnsignedT), ");")]
2379 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").unsigned_abs(), 100", stringify!($UnsignedT), ");")]
2380 /// assert_eq!((-128i8).unsigned_abs(), 128u8);
2381 /// ```
2382 #[stable(feature = "unsigned_abs", since = "1.51.0")]
2383 #[rustc_const_stable(feature = "unsigned_abs", since = "1.51.0")]
2384 #[must_use = "this returns the result of the operation, \
2385 without modifying the original"]
2386 #[inline]
2387 pub const fn unsigned_abs(self) -> $UnsignedT {
2388 self.wrapping_abs() as $UnsignedT
2389 }
2390
2391 /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
2392 /// wrapping around at the boundary of the type.
2393 ///
2394 /// # Examples
2395 ///
2396 /// ```
2397 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(4), 81);")]
2398 /// assert_eq!(3i8.wrapping_pow(5), -13);
2399 /// assert_eq!(3i8.wrapping_pow(6), -39);
2400 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_pow(0), 1);")]
2401 /// ```
2402 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2403 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2404 #[must_use = "this returns the result of the operation, \
2405 without modifying the original"]
2406 #[inline]
2407 pub const fn wrapping_pow(self, mut exp: u32) -> Self {
2408 if exp == 0 {
2409 return 1;
2410 }
2411 let mut base = self;
2412 let mut acc: Self = 1;
2413
2414 if intrinsics::is_val_statically_known(exp) {
2415 while exp > 1 {
2416 if (exp & 1) == 1 {
2417 acc = acc.wrapping_mul(base);
2418 }
2419 exp /= 2;
2420 base = base.wrapping_mul(base);
2421 }
2422
2423 // since exp!=0, finally the exp must be 1.
2424 // Deal with the final bit of the exponent separately, since
2425 // squaring the base afterwards is not necessary.
2426 acc.wrapping_mul(base)
2427 } else {
2428 // This is faster than the above when the exponent is not known
2429 // at compile time. We can't use the same code for the constant
2430 // exponent case because LLVM is currently unable to unroll
2431 // this loop.
2432 loop {
2433 if (exp & 1) == 1 {
2434 acc = acc.wrapping_mul(base);
2435 // since exp!=0, finally the exp must be 1.
2436 if exp == 1 {
2437 return acc;
2438 }
2439 }
2440 exp /= 2;
2441 base = base.wrapping_mul(base);
2442 }
2443 }
2444 }
2445
2446 /// Calculates `self` + `rhs`.
2447 ///
2448 /// Returns a tuple of the addition along with a boolean indicating
2449 /// whether an arithmetic overflow would occur. If an overflow would have
2450 /// occurred then the wrapped value is returned.
2451 ///
2452 /// # Examples
2453 ///
2454 /// ```
2455 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
2456 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (", stringify!($SelfT), "::MIN, true));")]
2457 /// ```
2458 #[stable(feature = "wrapping", since = "1.7.0")]
2459 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2460 #[must_use = "this returns the result of the operation, \
2461 without modifying the original"]
2462 #[inline(always)]
2463 pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
2464 let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
2465 (a as Self, b)
2466 }
2467
2468 /// Calculates `self` + `rhs` + `carry` and checks for overflow.
2469 ///
2470 /// Performs "ternary addition" of two integer operands and a carry-in
2471 /// bit, and returns a tuple of the sum along with a boolean indicating
2472 /// whether an arithmetic overflow would occur. On overflow, the wrapped
2473 /// value is returned.
2474 ///
2475 /// This allows chaining together multiple additions to create a wider
2476 /// addition, and can be useful for bignum addition. This method should
2477 /// only be used for the most significant word; for the less significant
2478 /// words the unsigned method
2479 #[doc = concat!("[`", stringify!($UnsignedT), "::carrying_add`]")]
2480 /// should be used.
2481 ///
2482 /// The output boolean returned by this method is *not* a carry flag,
2483 /// and should *not* be added to a more significant word.
2484 ///
2485 /// If the input carry is false, this method is equivalent to
2486 /// [`overflowing_add`](Self::overflowing_add).
2487 ///
2488 /// # Examples
2489 ///
2490 /// ```
2491 /// #![feature(bigint_helper_methods)]
2492 /// // Only the most significant word is signed.
2493 /// //
2494 #[doc = concat!("// 10 MAX (a = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2495 #[doc = concat!("// + -5 9 (b = -5 × 2^", stringify!($BITS), " + 9)")]
2496 /// // ---------
2497 #[doc = concat!("// 6 8 (sum = 6 × 2^", stringify!($BITS), " + 8)")]
2498 ///
2499 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (10, ", stringify!($UnsignedT), "::MAX);")]
2500 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (-5, 9);")]
2501 /// let carry0 = false;
2502 ///
2503 #[doc = concat!("// ", stringify!($UnsignedT), "::carrying_add for the less significant words")]
2504 /// let (sum0, carry1) = a0.carrying_add(b0, carry0);
2505 /// assert_eq!(carry1, true);
2506 ///
2507 #[doc = concat!("// ", stringify!($SelfT), "::carrying_add for the most significant word")]
2508 /// let (sum1, overflow) = a1.carrying_add(b1, carry1);
2509 /// assert_eq!(overflow, false);
2510 ///
2511 /// assert_eq!((sum1, sum0), (6, 8));
2512 /// ```
2513 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2514 #[must_use = "this returns the result of the operation, \
2515 without modifying the original"]
2516 #[inline]
2517 pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
2518 // note: longer-term this should be done via an intrinsic.
2519 // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
2520 let (a, b) = self.overflowing_add(rhs);
2521 let (c, d) = a.overflowing_add(carry as $SelfT);
2522 (c, b != d)
2523 }
2524
2525 /// Calculates `self` + `rhs` with an unsigned `rhs`.
2526 ///
2527 /// Returns a tuple of the addition along with a boolean indicating
2528 /// whether an arithmetic overflow would occur. If an overflow would
2529 /// have occurred then the wrapped value is returned.
2530 ///
2531 /// # Examples
2532 ///
2533 /// ```
2534 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_unsigned(2), (3, false));")]
2535 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_add_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MAX, false));")]
2536 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_unsigned(3), (", stringify!($SelfT), "::MIN, true));")]
2537 /// ```
2538 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2539 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2540 #[must_use = "this returns the result of the operation, \
2541 without modifying the original"]
2542 #[inline]
2543 pub const fn overflowing_add_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
2544 let rhs = rhs as Self;
2545 let (res, overflowed) = self.overflowing_add(rhs);
2546 (res, overflowed ^ (rhs < 0))
2547 }
2548
2549 /// Calculates `self` - `rhs`.
2550 ///
2551 /// Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow
2552 /// would occur. If an overflow would have occurred then the wrapped value is returned.
2553 ///
2554 /// # Examples
2555 ///
2556 /// ```
2557 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
2558 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
2559 /// ```
2560 #[stable(feature = "wrapping", since = "1.7.0")]
2561 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2562 #[must_use = "this returns the result of the operation, \
2563 without modifying the original"]
2564 #[inline(always)]
2565 pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
2566 let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
2567 (a as Self, b)
2568 }
2569
2570 /// Calculates `self` − `rhs` − `borrow` and checks for
2571 /// overflow.
2572 ///
2573 /// Performs "ternary subtraction" by subtracting both an integer
2574 /// operand and a borrow-in bit from `self`, and returns a tuple of the
2575 /// difference along with a boolean indicating whether an arithmetic
2576 /// overflow would occur. On overflow, the wrapped value is returned.
2577 ///
2578 /// This allows chaining together multiple subtractions to create a
2579 /// wider subtraction, and can be useful for bignum subtraction. This
2580 /// method should only be used for the most significant word; for the
2581 /// less significant words the unsigned method
2582 #[doc = concat!("[`", stringify!($UnsignedT), "::borrowing_sub`]")]
2583 /// should be used.
2584 ///
2585 /// The output boolean returned by this method is *not* a borrow flag,
2586 /// and should *not* be subtracted from a more significant word.
2587 ///
2588 /// If the input borrow is false, this method is equivalent to
2589 /// [`overflowing_sub`](Self::overflowing_sub).
2590 ///
2591 /// # Examples
2592 ///
2593 /// ```
2594 /// #![feature(bigint_helper_methods)]
2595 /// // Only the most significant word is signed.
2596 /// //
2597 #[doc = concat!("// 6 8 (a = 6 × 2^", stringify!($BITS), " + 8)")]
2598 #[doc = concat!("// - -5 9 (b = -5 × 2^", stringify!($BITS), " + 9)")]
2599 /// // ---------
2600 #[doc = concat!("// 10 MAX (diff = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2601 ///
2602 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (6, 8);")]
2603 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (-5, 9);")]
2604 /// let borrow0 = false;
2605 ///
2606 #[doc = concat!("// ", stringify!($UnsignedT), "::borrowing_sub for the less significant words")]
2607 /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
2608 /// assert_eq!(borrow1, true);
2609 ///
2610 #[doc = concat!("// ", stringify!($SelfT), "::borrowing_sub for the most significant word")]
2611 /// let (diff1, overflow) = a1.borrowing_sub(b1, borrow1);
2612 /// assert_eq!(overflow, false);
2613 ///
2614 #[doc = concat!("assert_eq!((diff1, diff0), (10, ", stringify!($UnsignedT), "::MAX));")]
2615 /// ```
2616 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2617 #[must_use = "this returns the result of the operation, \
2618 without modifying the original"]
2619 #[inline]
2620 pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
2621 // note: longer-term this should be done via an intrinsic.
2622 // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
2623 let (a, b) = self.overflowing_sub(rhs);
2624 let (c, d) = a.overflowing_sub(borrow as $SelfT);
2625 (c, b != d)
2626 }
2627
2628 /// Calculates `self` - `rhs` with an unsigned `rhs`.
2629 ///
2630 /// Returns a tuple of the subtraction along with a boolean indicating
2631 /// whether an arithmetic overflow would occur. If an overflow would
2632 /// have occurred then the wrapped value is returned.
2633 ///
2634 /// # Examples
2635 ///
2636 /// ```
2637 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_unsigned(2), (-1, false));")]
2638 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).overflowing_sub_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MIN, false));")]
2639 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).overflowing_sub_unsigned(3), (", stringify!($SelfT), "::MAX, true));")]
2640 /// ```
2641 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2642 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2643 #[must_use = "this returns the result of the operation, \
2644 without modifying the original"]
2645 #[inline]
2646 pub const fn overflowing_sub_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
2647 let rhs = rhs as Self;
2648 let (res, overflowed) = self.overflowing_sub(rhs);
2649 (res, overflowed ^ (rhs < 0))
2650 }
2651
2652 /// Calculates the multiplication of `self` and `rhs`.
2653 ///
2654 /// Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow
2655 /// would occur. If an overflow would have occurred then the wrapped value is returned.
2656 ///
2657 /// # Examples
2658 ///
2659 /// ```
2660 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_mul(2), (10, false));")]
2661 /// assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));
2662 /// ```
2663 #[stable(feature = "wrapping", since = "1.7.0")]
2664 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2665 #[must_use = "this returns the result of the operation, \
2666 without modifying the original"]
2667 #[inline(always)]
2668 pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
2669 let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
2670 (a as Self, b)
2671 }
2672
2673 /// Calculates the complete product `self * rhs` without the possibility to overflow.
2674 ///
2675 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2676 /// of the result as two separate values, in that order.
2677 ///
2678 /// If you also need to add a carry to the wide result, then you want
2679 /// [`Self::carrying_mul`] instead.
2680 ///
2681 /// # Examples
2682 ///
2683 /// Please note that this example is shared among integer types, which is why `i32` is used.
2684 ///
2685 /// ```
2686 /// #![feature(bigint_helper_methods)]
2687 /// assert_eq!(5i32.widening_mul(-2), (4294967286, -1));
2688 /// assert_eq!(1_000_000_000i32.widening_mul(-10), (2884901888, -3));
2689 /// ```
2690 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2691 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2692 #[must_use = "this returns the result of the operation, \
2693 without modifying the original"]
2694 #[inline]
2695 pub const fn widening_mul(self, rhs: Self) -> ($UnsignedT, Self) {
2696 Self::carrying_mul_add(self, rhs, 0, 0)
2697 }
2698
2699 /// Calculates the "full multiplication" `self * rhs + carry`
2700 /// without the possibility to overflow.
2701 ///
2702 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2703 /// of the result as two separate values, in that order.
2704 ///
2705 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2706 /// additional amount of overflow. This allows for chaining together multiple
2707 /// multiplications to create "big integers" which represent larger values.
2708 ///
2709 /// If you don't need the `carry`, then you can use [`Self::widening_mul`] instead.
2710 ///
2711 /// # Examples
2712 ///
2713 /// Please note that this example is shared among integer types, which is why `i32` is used.
2714 ///
2715 /// ```
2716 /// #![feature(bigint_helper_methods)]
2717 /// assert_eq!(5i32.carrying_mul(-2, 0), (4294967286, -1));
2718 /// assert_eq!(5i32.carrying_mul(-2, 10), (0, 0));
2719 /// assert_eq!(1_000_000_000i32.carrying_mul(-10, 0), (2884901888, -3));
2720 /// assert_eq!(1_000_000_000i32.carrying_mul(-10, 10), (2884901898, -3));
2721 #[doc = concat!("assert_eq!(",
2722 stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2723 "(", stringify!($SelfT), "::MAX.unsigned_abs() + 1, ", stringify!($SelfT), "::MAX / 2));"
2724 )]
2725 /// ```
2726 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2727 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2728 #[must_use = "this returns the result of the operation, \
2729 without modifying the original"]
2730 #[inline]
2731 pub const fn carrying_mul(self, rhs: Self, carry: Self) -> ($UnsignedT, Self) {
2732 Self::carrying_mul_add(self, rhs, carry, 0)
2733 }
2734
2735 /// Calculates the "full multiplication" `self * rhs + carry + add`
2736 /// without the possibility to overflow.
2737 ///
2738 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2739 /// of the result as two separate values, in that order.
2740 ///
2741 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2742 /// additional amount of overflow. This allows for chaining together multiple
2743 /// multiplications to create "big integers" which represent larger values.
2744 ///
2745 /// If you don't need either `carry`, then you can use [`Self::widening_mul`] instead,
2746 /// and if you only need one `carry`, then you can use [`Self::carrying_mul`] instead.
2747 ///
2748 /// # Examples
2749 ///
2750 /// Please note that this example is shared among integer types, which is why `i32` is used.
2751 ///
2752 /// ```
2753 /// #![feature(bigint_helper_methods)]
2754 /// assert_eq!(5i32.carrying_mul_add(-2, 0, 0), (4294967286, -1));
2755 /// assert_eq!(5i32.carrying_mul_add(-2, 10, 10), (10, 0));
2756 /// assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 0, 0), (2884901888, -3));
2757 /// assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 10, 10), (2884901908, -3));
2758 #[doc = concat!("assert_eq!(",
2759 stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2760 "(", stringify!($UnsignedT), "::MAX, ", stringify!($SelfT), "::MAX / 2));"
2761 )]
2762 /// ```
2763 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
2764 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
2765 #[must_use = "this returns the result of the operation, \
2766 without modifying the original"]
2767 #[inline]
2768 pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> ($UnsignedT, Self) {
2769 intrinsics::carrying_mul_add(self, rhs, carry, add)
2770 }
2771
2772 /// Calculates the divisor when `self` is divided by `rhs`.
2773 ///
2774 /// Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
2775 /// occur. If an overflow would occur then self is returned.
2776 ///
2777 /// # Panics
2778 ///
2779 /// This function will panic if `rhs` is zero.
2780 ///
2781 /// # Examples
2782 ///
2783 /// ```
2784 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
2785 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div(-1), (", stringify!($SelfT), "::MIN, true));")]
2786 /// ```
2787 #[inline]
2788 #[stable(feature = "wrapping", since = "1.7.0")]
2789 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2790 #[must_use = "this returns the result of the operation, \
2791 without modifying the original"]
2792 pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
2793 // Using `&` helps LLVM see that it is the same check made in division.
2794 if intrinsics::unlikely((self == Self::MIN) & (rhs == -1)) {
2795 (self, true)
2796 } else {
2797 (self / rhs, false)
2798 }
2799 }
2800
2801 /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`.
2802 ///
2803 /// Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
2804 /// occur. If an overflow would occur then `self` is returned.
2805 ///
2806 /// # Panics
2807 ///
2808 /// This function will panic if `rhs` is zero.
2809 ///
2810 /// # Examples
2811 ///
2812 /// ```
2813 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
2814 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div_euclid(-1), (", stringify!($SelfT), "::MIN, true));")]
2815 /// ```
2816 #[inline]
2817 #[stable(feature = "euclidean_division", since = "1.38.0")]
2818 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2819 #[must_use = "this returns the result of the operation, \
2820 without modifying the original"]
2821 pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
2822 // Using `&` helps LLVM see that it is the same check made in division.
2823 if intrinsics::unlikely((self == Self::MIN) & (rhs == -1)) {
2824 (self, true)
2825 } else {
2826 (self.div_euclid(rhs), false)
2827 }
2828 }
2829
2830 /// Calculates the remainder when `self` is divided by `rhs`.
2831 ///
2832 /// Returns a tuple of the remainder after dividing along with a boolean indicating whether an
2833 /// arithmetic overflow would occur. If an overflow would occur then 0 is returned.
2834 ///
2835 /// # Panics
2836 ///
2837 /// This function will panic if `rhs` is zero.
2838 ///
2839 /// # Examples
2840 ///
2841 /// ```
2842 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
2843 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem(-1), (0, true));")]
2844 /// ```
2845 #[inline]
2846 #[stable(feature = "wrapping", since = "1.7.0")]
2847 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2848 #[must_use = "this returns the result of the operation, \
2849 without modifying the original"]
2850 pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
2851 if intrinsics::unlikely(rhs == -1) {
2852 (0, self == Self::MIN)
2853 } else {
2854 (self % rhs, false)
2855 }
2856 }
2857
2858
2859 /// Overflowing Euclidean remainder. Calculates `self.rem_euclid(rhs)`.
2860 ///
2861 /// Returns a tuple of the remainder after dividing along with a boolean indicating whether an
2862 /// arithmetic overflow would occur. If an overflow would occur then 0 is returned.
2863 ///
2864 /// # Panics
2865 ///
2866 /// This function will panic if `rhs` is zero.
2867 ///
2868 /// # Examples
2869 ///
2870 /// ```
2871 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
2872 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem_euclid(-1), (0, true));")]
2873 /// ```
2874 #[stable(feature = "euclidean_division", since = "1.38.0")]
2875 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2876 #[must_use = "this returns the result of the operation, \
2877 without modifying the original"]
2878 #[inline]
2879 #[track_caller]
2880 pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
2881 if intrinsics::unlikely(rhs == -1) {
2882 (0, self == Self::MIN)
2883 } else {
2884 (self.rem_euclid(rhs), false)
2885 }
2886 }
2887
2888
2889 /// Negates self, overflowing if this is equal to the minimum value.
2890 ///
2891 /// Returns a tuple of the negated version of self along with a boolean indicating whether an overflow
2892 /// happened. If `self` is the minimum value (e.g., `i32::MIN` for values of type `i32`), then the
2893 /// minimum value will be returned again and `true` will be returned for an overflow happening.
2894 ///
2895 /// # Examples
2896 ///
2897 /// ```
2898 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2, false));")]
2899 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_neg(), (", stringify!($SelfT), "::MIN, true));")]
2900 /// ```
2901 #[inline]
2902 #[stable(feature = "wrapping", since = "1.7.0")]
2903 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2904 #[must_use = "this returns the result of the operation, \
2905 without modifying the original"]
2906 #[allow(unused_attributes)]
2907 pub const fn overflowing_neg(self) -> (Self, bool) {
2908 if intrinsics::unlikely(self == Self::MIN) {
2909 (Self::MIN, true)
2910 } else {
2911 (-self, false)
2912 }
2913 }
2914
2915 /// Shifts self left by `rhs` bits.
2916 ///
2917 /// Returns a tuple of the shifted version of self along with a boolean indicating whether the shift
2918 /// value was larger than or equal to the number of bits. If the shift value is too large, then value is
2919 /// masked (N-1) where N is the number of bits, and this value is then used to perform the shift.
2920 ///
2921 /// # Examples
2922 ///
2923 /// ```
2924 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT),".overflowing_shl(4), (0x10, false));")]
2925 /// assert_eq!(0x1i32.overflowing_shl(36), (0x10, true));
2926 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
2927 /// ```
2928 #[stable(feature = "wrapping", since = "1.7.0")]
2929 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2930 #[must_use = "this returns the result of the operation, \
2931 without modifying the original"]
2932 #[inline]
2933 pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
2934 (self.wrapping_shl(rhs), rhs >= Self::BITS)
2935 }
2936
2937 /// Shifts self right by `rhs` bits.
2938 ///
2939 /// Returns a tuple of the shifted version of self along with a boolean indicating whether the shift
2940 /// value was larger than or equal to the number of bits. If the shift value is too large, then value is
2941 /// masked (N-1) where N is the number of bits, and this value is then used to perform the shift.
2942 ///
2943 /// # Examples
2944 ///
2945 /// ```
2946 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
2947 /// assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
2948 /// ```
2949 #[stable(feature = "wrapping", since = "1.7.0")]
2950 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2951 #[must_use = "this returns the result of the operation, \
2952 without modifying the original"]
2953 #[inline]
2954 pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
2955 (self.wrapping_shr(rhs), rhs >= Self::BITS)
2956 }
2957
2958 /// Computes the absolute value of `self`.
2959 ///
2960 /// Returns a tuple of the absolute version of self along with a boolean indicating whether an overflow
2961 /// happened. If self is the minimum value
2962 #[doc = concat!("(e.g., ", stringify!($SelfT), "::MIN for values of type ", stringify!($SelfT), "),")]
2963 /// then the minimum value will be returned again and true will be returned
2964 /// for an overflow happening.
2965 ///
2966 /// # Examples
2967 ///
2968 /// ```
2969 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".overflowing_abs(), (10, false));")]
2970 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").overflowing_abs(), (10, false));")]
2971 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_abs(), (", stringify!($SelfT), "::MIN, true));")]
2972 /// ```
2973 #[stable(feature = "no_panic_abs", since = "1.13.0")]
2974 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2975 #[must_use = "this returns the result of the operation, \
2976 without modifying the original"]
2977 #[inline]
2978 pub const fn overflowing_abs(self) -> (Self, bool) {
2979 (self.wrapping_abs(), self == Self::MIN)
2980 }
2981
2982 /// Raises self to the power of `exp`, using exponentiation by squaring.
2983 ///
2984 /// Returns a tuple of the exponentiation along with a bool indicating
2985 /// whether an overflow happened.
2986 ///
2987 /// # Examples
2988 ///
2989 /// ```
2990 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(4), (81, false));")]
2991 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".overflowing_pow(0), (1, false));")]
2992 /// assert_eq!(3i8.overflowing_pow(5), (-13, true));
2993 /// ```
2994 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2995 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2996 #[must_use = "this returns the result of the operation, \
2997 without modifying the original"]
2998 #[inline]
2999 pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
3000 if exp == 0 {
3001 return (1,false);
3002 }
3003 let mut base = self;
3004 let mut acc: Self = 1;
3005 let mut overflown = false;
3006 // Scratch space for storing results of overflowing_mul.
3007 let mut r;
3008
3009 loop {
3010 if (exp & 1) == 1 {
3011 r = acc.overflowing_mul(base);
3012 // since exp!=0, finally the exp must be 1.
3013 if exp == 1 {
3014 r.1 |= overflown;
3015 return r;
3016 }
3017 acc = r.0;
3018 overflown |= r.1;
3019 }
3020 exp /= 2;
3021 r = base.overflowing_mul(base);
3022 base = r.0;
3023 overflown |= r.1;
3024 }
3025 }
3026
3027 /// Raises self to the power of `exp`, using exponentiation by squaring.
3028 ///
3029 /// # Examples
3030 ///
3031 /// ```
3032 #[doc = concat!("let x: ", stringify!($SelfT), " = 2; // or any other integer type")]
3033 ///
3034 /// assert_eq!(x.pow(5), 32);
3035 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".pow(0), 1);")]
3036 /// ```
3037 #[stable(feature = "rust1", since = "1.0.0")]
3038 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3039 #[must_use = "this returns the result of the operation, \
3040 without modifying the original"]
3041 #[inline]
3042 #[rustc_inherit_overflow_checks]
3043 pub const fn pow(self, mut exp: u32) -> Self {
3044 if exp == 0 {
3045 return 1;
3046 }
3047 let mut base = self;
3048 let mut acc = 1;
3049
3050 if intrinsics::is_val_statically_known(exp) {
3051 while exp > 1 {
3052 if (exp & 1) == 1 {
3053 acc = acc * base;
3054 }
3055 exp /= 2;
3056 base = base * base;
3057 }
3058
3059 // since exp!=0, finally the exp must be 1.
3060 // Deal with the final bit of the exponent separately, since
3061 // squaring the base afterwards is not necessary and may cause a
3062 // needless overflow.
3063 acc * base
3064 } else {
3065 // This is faster than the above when the exponent is not known
3066 // at compile time. We can't use the same code for the constant
3067 // exponent case because LLVM is currently unable to unroll
3068 // this loop.
3069 loop {
3070 if (exp & 1) == 1 {
3071 acc = acc * base;
3072 // since exp!=0, finally the exp must be 1.
3073 if exp == 1 {
3074 return acc;
3075 }
3076 }
3077 exp /= 2;
3078 base = base * base;
3079 }
3080 }
3081 }
3082
3083 /// Returns the square root of the number, rounded down.
3084 ///
3085 /// # Panics
3086 ///
3087 /// This function will panic if `self` is negative.
3088 ///
3089 /// # Examples
3090 ///
3091 /// ```
3092 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
3093 /// ```
3094 #[stable(feature = "isqrt", since = "1.84.0")]
3095 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
3096 #[must_use = "this returns the result of the operation, \
3097 without modifying the original"]
3098 #[inline]
3099 #[track_caller]
3100 pub const fn isqrt(self) -> Self {
3101 match self.checked_isqrt() {
3102 Some(sqrt) => sqrt,
3103 None => crate::num::int_sqrt::panic_for_negative_argument(),
3104 }
3105 }
3106
3107 /// Calculates the quotient of Euclidean division of `self` by `rhs`.
3108 ///
3109 /// This computes the integer `q` such that `self = q * rhs + r`, with
3110 /// `r = self.rem_euclid(rhs)` and `0 <= r < abs(rhs)`.
3111 ///
3112 /// In other words, the result is `self / rhs` rounded to the integer `q`
3113 /// such that `self >= q * rhs`.
3114 /// If `self > 0`, this is equal to rounding towards zero (the default in Rust);
3115 /// if `self < 0`, this is equal to rounding away from zero (towards +/- infinity).
3116 /// If `rhs > 0`, this is equal to rounding towards -infinity;
3117 /// if `rhs < 0`, this is equal to rounding towards +infinity.
3118 ///
3119 /// # Panics
3120 ///
3121 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3122 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3123 ///
3124 /// # Examples
3125 ///
3126 /// ```
3127 #[doc = concat!("let a: ", stringify!($SelfT), " = 7; // or any other integer type")]
3128 /// let b = 4;
3129 ///
3130 /// assert_eq!(a.div_euclid(b), 1); // 7 >= 4 * 1
3131 /// assert_eq!(a.div_euclid(-b), -1); // 7 >= -4 * -1
3132 /// assert_eq!((-a).div_euclid(b), -2); // -7 >= 4 * -2
3133 /// assert_eq!((-a).div_euclid(-b), 2); // -7 >= -4 * 2
3134 /// ```
3135 #[stable(feature = "euclidean_division", since = "1.38.0")]
3136 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3137 #[must_use = "this returns the result of the operation, \
3138 without modifying the original"]
3139 #[inline]
3140 #[track_caller]
3141 pub const fn div_euclid(self, rhs: Self) -> Self {
3142 let q = self / rhs;
3143 if self % rhs < 0 {
3144 return if rhs > 0 { q - 1 } else { q + 1 }
3145 }
3146 q
3147 }
3148
3149
3150 /// Calculates the least nonnegative remainder of `self` when
3151 /// divided by `rhs`.
3152 ///
3153 /// This is done as if by the Euclidean division algorithm -- given
3154 /// `r = self.rem_euclid(rhs)`, the result satisfies
3155 /// `self = rhs * self.div_euclid(rhs) + r` and `0 <= r < abs(rhs)`.
3156 ///
3157 /// # Panics
3158 ///
3159 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN` and
3160 /// `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3161 ///
3162 /// # Examples
3163 ///
3164 /// ```
3165 #[doc = concat!("let a: ", stringify!($SelfT), " = 7; // or any other integer type")]
3166 /// let b = 4;
3167 ///
3168 /// assert_eq!(a.rem_euclid(b), 3);
3169 /// assert_eq!((-a).rem_euclid(b), 1);
3170 /// assert_eq!(a.rem_euclid(-b), 3);
3171 /// assert_eq!((-a).rem_euclid(-b), 1);
3172 /// ```
3173 ///
3174 /// This will panic:
3175 /// ```should_panic
3176 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.rem_euclid(-1);")]
3177 /// ```
3178 #[doc(alias = "modulo", alias = "mod")]
3179 #[stable(feature = "euclidean_division", since = "1.38.0")]
3180 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3181 #[must_use = "this returns the result of the operation, \
3182 without modifying the original"]
3183 #[inline]
3184 #[track_caller]
3185 pub const fn rem_euclid(self, rhs: Self) -> Self {
3186 let r = self % rhs;
3187 if r < 0 {
3188 // Semantically equivalent to `if rhs < 0 { r - rhs } else { r + rhs }`.
3189 // If `rhs` is not `Self::MIN`, then `r + abs(rhs)` will not overflow
3190 // and is clearly equivalent, because `r` is negative.
3191 // Otherwise, `rhs` is `Self::MIN`, then we have
3192 // `r.wrapping_add(Self::MIN.wrapping_abs())`, which evaluates
3193 // to `r.wrapping_add(Self::MIN)`, which is equivalent to
3194 // `r - Self::MIN`, which is what we wanted (and will not overflow
3195 // for negative `r`).
3196 r.wrapping_add(rhs.wrapping_abs())
3197 } else {
3198 r
3199 }
3200 }
3201
3202 /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
3203 ///
3204 /// # Panics
3205 ///
3206 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3207 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3208 ///
3209 /// # Examples
3210 ///
3211 /// ```
3212 /// #![feature(int_roundings)]
3213 #[doc = concat!("let a: ", stringify!($SelfT)," = 8;")]
3214 /// let b = 3;
3215 ///
3216 /// assert_eq!(a.div_floor(b), 2);
3217 /// assert_eq!(a.div_floor(-b), -3);
3218 /// assert_eq!((-a).div_floor(b), -3);
3219 /// assert_eq!((-a).div_floor(-b), 2);
3220 /// ```
3221 #[unstable(feature = "int_roundings", issue = "88581")]
3222 #[must_use = "this returns the result of the operation, \
3223 without modifying the original"]
3224 #[inline]
3225 #[track_caller]
3226 pub const fn div_floor(self, rhs: Self) -> Self {
3227 let d = self / rhs;
3228 let r = self % rhs;
3229
3230 // If the remainder is non-zero, we need to subtract one if the
3231 // signs of self and rhs differ, as this means we rounded upwards
3232 // instead of downwards. We do this branchlessly by creating a mask
3233 // which is all-ones iff the signs differ, and 0 otherwise. Then by
3234 // adding this mask (which corresponds to the signed value -1), we
3235 // get our correction.
3236 let correction = (self ^ rhs) >> (Self::BITS - 1);
3237 if r != 0 {
3238 d + correction
3239 } else {
3240 d
3241 }
3242 }
3243
3244 /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
3245 ///
3246 /// # Panics
3247 ///
3248 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3249 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3250 ///
3251 /// # Examples
3252 ///
3253 /// ```
3254 /// #![feature(int_roundings)]
3255 #[doc = concat!("let a: ", stringify!($SelfT)," = 8;")]
3256 /// let b = 3;
3257 ///
3258 /// assert_eq!(a.div_ceil(b), 3);
3259 /// assert_eq!(a.div_ceil(-b), -2);
3260 /// assert_eq!((-a).div_ceil(b), -2);
3261 /// assert_eq!((-a).div_ceil(-b), 3);
3262 /// ```
3263 #[unstable(feature = "int_roundings", issue = "88581")]
3264 #[must_use = "this returns the result of the operation, \
3265 without modifying the original"]
3266 #[inline]
3267 #[track_caller]
3268 pub const fn div_ceil(self, rhs: Self) -> Self {
3269 let d = self / rhs;
3270 let r = self % rhs;
3271
3272 // When remainder is non-zero we have a.div_ceil(b) == 1 + a.div_floor(b),
3273 // so we can re-use the algorithm from div_floor, just adding 1.
3274 let correction = 1 + ((self ^ rhs) >> (Self::BITS - 1));
3275 if r != 0 {
3276 d + correction
3277 } else {
3278 d
3279 }
3280 }
3281
3282 /// If `rhs` is positive, calculates the smallest value greater than or
3283 /// equal to `self` that is a multiple of `rhs`. If `rhs` is negative,
3284 /// calculates the largest value less than or equal to `self` that is a
3285 /// multiple of `rhs`.
3286 ///
3287 /// # Panics
3288 ///
3289 /// This function will panic if `rhs` is zero.
3290 ///
3291 /// ## Overflow behavior
3292 ///
3293 /// On overflow, this function will panic if overflow checks are enabled (default in debug
3294 /// mode) and wrap if overflow checks are disabled (default in release mode).
3295 ///
3296 /// # Examples
3297 ///
3298 /// ```
3299 /// #![feature(int_roundings)]
3300 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
3301 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
3302 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(-8), 16);")]
3303 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(-8), 16);")]
3304 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").next_multiple_of(8), -16);")]
3305 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").next_multiple_of(8), -16);")]
3306 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").next_multiple_of(-8), -16);")]
3307 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").next_multiple_of(-8), -24);")]
3308 /// ```
3309 #[unstable(feature = "int_roundings", issue = "88581")]
3310 #[must_use = "this returns the result of the operation, \
3311 without modifying the original"]
3312 #[inline]
3313 #[rustc_inherit_overflow_checks]
3314 pub const fn next_multiple_of(self, rhs: Self) -> Self {
3315 // This would otherwise fail when calculating `r` when self == T::MIN.
3316 if rhs == -1 {
3317 return self;
3318 }
3319
3320 let r = self % rhs;
3321 let m = if (r > 0 && rhs < 0) || (r < 0 && rhs > 0) {
3322 r + rhs
3323 } else {
3324 r
3325 };
3326
3327 if m == 0 {
3328 self
3329 } else {
3330 self + (rhs - m)
3331 }
3332 }
3333
3334 /// If `rhs` is positive, calculates the smallest value greater than or
3335 /// equal to `self` that is a multiple of `rhs`. If `rhs` is negative,
3336 /// calculates the largest value less than or equal to `self` that is a
3337 /// multiple of `rhs`. Returns `None` if `rhs` is zero or the operation
3338 /// would result in overflow.
3339 ///
3340 /// # Examples
3341 ///
3342 /// ```
3343 /// #![feature(int_roundings)]
3344 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
3345 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
3346 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(-8), Some(16));")]
3347 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(-8), Some(16));")]
3348 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").checked_next_multiple_of(8), Some(-16));")]
3349 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").checked_next_multiple_of(8), Some(-16));")]
3350 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").checked_next_multiple_of(-8), Some(-16));")]
3351 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").checked_next_multiple_of(-8), Some(-24));")]
3352 #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
3353 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
3354 /// ```
3355 #[unstable(feature = "int_roundings", issue = "88581")]
3356 #[must_use = "this returns the result of the operation, \
3357 without modifying the original"]
3358 #[inline]
3359 pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
3360 // This would otherwise fail when calculating `r` when self == T::MIN.
3361 if rhs == -1 {
3362 return Some(self);
3363 }
3364
3365 let r = try_opt!(self.checked_rem(rhs));
3366 let m = if (r > 0 && rhs < 0) || (r < 0 && rhs > 0) {
3367 // r + rhs cannot overflow because they have opposite signs
3368 r + rhs
3369 } else {
3370 r
3371 };
3372
3373 if m == 0 {
3374 Some(self)
3375 } else {
3376 // rhs - m cannot overflow because m has the same sign as rhs
3377 self.checked_add(rhs - m)
3378 }
3379 }
3380
3381 /// Returns the logarithm of the number with respect to an arbitrary base,
3382 /// rounded down.
3383 ///
3384 /// This method might not be optimized owing to implementation details;
3385 /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
3386 /// can produce results more efficiently for base 10.
3387 ///
3388 /// # Panics
3389 ///
3390 /// This function will panic if `self` is less than or equal to zero,
3391 /// or if `base` is less than 2.
3392 ///
3393 /// # Examples
3394 ///
3395 /// ```
3396 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
3397 /// ```
3398 #[stable(feature = "int_log", since = "1.67.0")]
3399 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3400 #[must_use = "this returns the result of the operation, \
3401 without modifying the original"]
3402 #[inline]
3403 #[track_caller]
3404 pub const fn ilog(self, base: Self) -> u32 {
3405 assert!(base >= 2, "base of integer logarithm must be at least 2");
3406 if let Some(log) = self.checked_ilog(base) {
3407 log
3408 } else {
3409 int_log10::panic_for_nonpositive_argument()
3410 }
3411 }
3412
3413 /// Returns the base 2 logarithm of the number, rounded down.
3414 ///
3415 /// # Panics
3416 ///
3417 /// This function will panic if `self` is less than or equal to zero.
3418 ///
3419 /// # Examples
3420 ///
3421 /// ```
3422 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
3423 /// ```
3424 #[stable(feature = "int_log", since = "1.67.0")]
3425 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3426 #[must_use = "this returns the result of the operation, \
3427 without modifying the original"]
3428 #[inline]
3429 #[track_caller]
3430 pub const fn ilog2(self) -> u32 {
3431 if let Some(log) = self.checked_ilog2() {
3432 log
3433 } else {
3434 int_log10::panic_for_nonpositive_argument()
3435 }
3436 }
3437
3438 /// Returns the base 10 logarithm of the number, rounded down.
3439 ///
3440 /// # Panics
3441 ///
3442 /// This function will panic if `self` is less than or equal to zero.
3443 ///
3444 /// # Example
3445 ///
3446 /// ```
3447 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
3448 /// ```
3449 #[stable(feature = "int_log", since = "1.67.0")]
3450 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3451 #[must_use = "this returns the result of the operation, \
3452 without modifying the original"]
3453 #[inline]
3454 #[track_caller]
3455 pub const fn ilog10(self) -> u32 {
3456 if let Some(log) = self.checked_ilog10() {
3457 log
3458 } else {
3459 int_log10::panic_for_nonpositive_argument()
3460 }
3461 }
3462
3463 /// Returns the logarithm of the number with respect to an arbitrary base,
3464 /// rounded down.
3465 ///
3466 /// Returns `None` if the number is negative or zero, or if the base is not at least 2.
3467 ///
3468 /// This method might not be optimized owing to implementation details;
3469 /// `checked_ilog2` can produce results more efficiently for base 2, and
3470 /// `checked_ilog10` can produce results more efficiently for base 10.
3471 ///
3472 /// # Examples
3473 ///
3474 /// ```
3475 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
3476 /// ```
3477 #[stable(feature = "int_log", since = "1.67.0")]
3478 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3479 #[must_use = "this returns the result of the operation, \
3480 without modifying the original"]
3481 #[inline]
3482 pub const fn checked_ilog(self, base: Self) -> Option<u32> {
3483 if self <= 0 || base <= 1 {
3484 None
3485 } else {
3486 // Delegate to the unsigned implementation.
3487 // The condition makes sure that both casts are exact.
3488 (self as $UnsignedT).checked_ilog(base as $UnsignedT)
3489 }
3490 }
3491
3492 /// Returns the base 2 logarithm of the number, rounded down.
3493 ///
3494 /// Returns `None` if the number is negative or zero.
3495 ///
3496 /// # Examples
3497 ///
3498 /// ```
3499 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
3500 /// ```
3501 #[stable(feature = "int_log", since = "1.67.0")]
3502 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3503 #[must_use = "this returns the result of the operation, \
3504 without modifying the original"]
3505 #[inline]
3506 pub const fn checked_ilog2(self) -> Option<u32> {
3507 if self <= 0 {
3508 None
3509 } else {
3510 // SAFETY: We just checked that this number is positive
3511 let log = (Self::BITS - 1) - unsafe { intrinsics::ctlz_nonzero(self) as u32 };
3512 Some(log)
3513 }
3514 }
3515
3516 /// Returns the base 10 logarithm of the number, rounded down.
3517 ///
3518 /// Returns `None` if the number is negative or zero.
3519 ///
3520 /// # Example
3521 ///
3522 /// ```
3523 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
3524 /// ```
3525 #[stable(feature = "int_log", since = "1.67.0")]
3526 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3527 #[must_use = "this returns the result of the operation, \
3528 without modifying the original"]
3529 #[inline]
3530 pub const fn checked_ilog10(self) -> Option<u32> {
3531 int_log10::$ActualT(self as $ActualT)
3532 }
3533
3534 /// Computes the absolute value of `self`.
3535 ///
3536 /// # Overflow behavior
3537 ///
3538 /// The absolute value of
3539 #[doc = concat!("`", stringify!($SelfT), "::MIN`")]
3540 /// cannot be represented as an
3541 #[doc = concat!("`", stringify!($SelfT), "`,")]
3542 /// and attempting to calculate it will cause an overflow. This means
3543 /// that code in debug mode will trigger a panic on this case and
3544 /// optimized code will return
3545 #[doc = concat!("`", stringify!($SelfT), "::MIN`")]
3546 /// without a panic. If you do not want this behavior, consider
3547 /// using [`unsigned_abs`](Self::unsigned_abs) instead.
3548 ///
3549 /// # Examples
3550 ///
3551 /// ```
3552 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".abs(), 10);")]
3553 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").abs(), 10);")]
3554 /// ```
3555 #[stable(feature = "rust1", since = "1.0.0")]
3556 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3557 #[allow(unused_attributes)]
3558 #[must_use = "this returns the result of the operation, \
3559 without modifying the original"]
3560 #[inline]
3561 #[rustc_inherit_overflow_checks]
3562 pub const fn abs(self) -> Self {
3563 // Note that the #[rustc_inherit_overflow_checks] and #[inline]
3564 // above mean that the overflow semantics of the subtraction
3565 // depend on the crate we're being called from.
3566 if self.is_negative() {
3567 -self
3568 } else {
3569 self
3570 }
3571 }
3572
3573 /// Computes the absolute difference between `self` and `other`.
3574 ///
3575 /// This function always returns the correct answer without overflow or
3576 /// panics by returning an unsigned integer.
3577 ///
3578 /// # Examples
3579 ///
3580 /// ```
3581 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($UnsignedT), ");")]
3582 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($UnsignedT), ");")]
3583 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").abs_diff(80), 180", stringify!($UnsignedT), ");")]
3584 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").abs_diff(-120), 20", stringify!($UnsignedT), ");")]
3585 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.abs_diff(", stringify!($SelfT), "::MAX), ", stringify!($UnsignedT), "::MAX);")]
3586 /// ```
3587 #[stable(feature = "int_abs_diff", since = "1.60.0")]
3588 #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
3589 #[must_use = "this returns the result of the operation, \
3590 without modifying the original"]
3591 #[inline]
3592 pub const fn abs_diff(self, other: Self) -> $UnsignedT {
3593 if self < other {
3594 // Converting a non-negative x from signed to unsigned by using
3595 // `x as U` is left unchanged, but a negative x is converted
3596 // to value x + 2^N. Thus if `s` and `o` are binary variables
3597 // respectively indicating whether `self` and `other` are
3598 // negative, we are computing the mathematical value:
3599 //
3600 // (other + o*2^N) - (self + s*2^N) mod 2^N
3601 // other - self + (o-s)*2^N mod 2^N
3602 // other - self mod 2^N
3603 //
3604 // Finally, taking the mod 2^N of the mathematical value of
3605 // `other - self` does not change it as it already is
3606 // in the range [0, 2^N).
3607 (other as $UnsignedT).wrapping_sub(self as $UnsignedT)
3608 } else {
3609 (self as $UnsignedT).wrapping_sub(other as $UnsignedT)
3610 }
3611 }
3612
3613 /// Returns a number representing sign of `self`.
3614 ///
3615 /// - `0` if the number is zero
3616 /// - `1` if the number is positive
3617 /// - `-1` if the number is negative
3618 ///
3619 /// # Examples
3620 ///
3621 /// ```
3622 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".signum(), 1);")]
3623 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".signum(), 0);")]
3624 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").signum(), -1);")]
3625 /// ```
3626 #[stable(feature = "rust1", since = "1.0.0")]
3627 #[rustc_const_stable(feature = "const_int_sign", since = "1.47.0")]
3628 #[must_use = "this returns the result of the operation, \
3629 without modifying the original"]
3630 #[inline(always)]
3631 pub const fn signum(self) -> Self {
3632 // Picking the right way to phrase this is complicated
3633 // (<https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>)
3634 // so delegate it to `Ord` which is already producing -1/0/+1
3635 // exactly like we need and can be the place to deal with the complexity.
3636
3637 crate::intrinsics::three_way_compare(self, 0) as Self
3638 }
3639
3640 /// Returns `true` if `self` is positive and `false` if the number is zero or
3641 /// negative.
3642 ///
3643 /// # Examples
3644 ///
3645 /// ```
3646 #[doc = concat!("assert!(10", stringify!($SelfT), ".is_positive());")]
3647 #[doc = concat!("assert!(!(-10", stringify!($SelfT), ").is_positive());")]
3648 /// ```
3649 #[must_use]
3650 #[stable(feature = "rust1", since = "1.0.0")]
3651 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3652 #[inline(always)]
3653 pub const fn is_positive(self) -> bool { self > 0 }
3654
3655 /// Returns `true` if `self` is negative and `false` if the number is zero or
3656 /// positive.
3657 ///
3658 /// # Examples
3659 ///
3660 /// ```
3661 #[doc = concat!("assert!((-10", stringify!($SelfT), ").is_negative());")]
3662 #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_negative());")]
3663 /// ```
3664 #[must_use]
3665 #[stable(feature = "rust1", since = "1.0.0")]
3666 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3667 #[inline(always)]
3668 pub const fn is_negative(self) -> bool { self < 0 }
3669
3670 /// Returns the memory representation of this integer as a byte array in
3671 /// big-endian (network) byte order.
3672 ///
3673 #[doc = $to_xe_bytes_doc]
3674 ///
3675 /// # Examples
3676 ///
3677 /// ```
3678 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
3679 #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
3680 /// ```
3681 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3682 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3683 #[must_use = "this returns the result of the operation, \
3684 without modifying the original"]
3685 #[inline]
3686 pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] {
3687 self.to_be().to_ne_bytes()
3688 }
3689
3690 /// Returns the memory representation of this integer as a byte array in
3691 /// little-endian byte order.
3692 ///
3693 #[doc = $to_xe_bytes_doc]
3694 ///
3695 /// # Examples
3696 ///
3697 /// ```
3698 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
3699 #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
3700 /// ```
3701 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3702 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3703 #[must_use = "this returns the result of the operation, \
3704 without modifying the original"]
3705 #[inline]
3706 pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] {
3707 self.to_le().to_ne_bytes()
3708 }
3709
3710 /// Returns the memory representation of this integer as a byte array in
3711 /// native byte order.
3712 ///
3713 /// As the target platform's native endianness is used, portable code
3714 /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
3715 /// instead.
3716 ///
3717 #[doc = $to_xe_bytes_doc]
3718 ///
3719 /// [`to_be_bytes`]: Self::to_be_bytes
3720 /// [`to_le_bytes`]: Self::to_le_bytes
3721 ///
3722 /// # Examples
3723 ///
3724 /// ```
3725 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
3726 /// assert_eq!(
3727 /// bytes,
3728 /// if cfg!(target_endian = "big") {
3729 #[doc = concat!(" ", $be_bytes)]
3730 /// } else {
3731 #[doc = concat!(" ", $le_bytes)]
3732 /// }
3733 /// );
3734 /// ```
3735 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3736 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3737 #[allow(unnecessary_transmutes)]
3738 // SAFETY: const sound because integers are plain old datatypes so we can always
3739 // transmute them to arrays of bytes
3740 #[must_use = "this returns the result of the operation, \
3741 without modifying the original"]
3742 #[inline]
3743 pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] {
3744 // SAFETY: integers are plain old datatypes so we can always transmute them to
3745 // arrays of bytes
3746 unsafe { mem::transmute(self) }
3747 }
3748
3749 /// Creates an integer value from its representation as a byte array in
3750 /// big endian.
3751 ///
3752 #[doc = $from_xe_bytes_doc]
3753 ///
3754 /// # Examples
3755 ///
3756 /// ```
3757 #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
3758 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3759 /// ```
3760 ///
3761 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3762 ///
3763 /// ```
3764 #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3765 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3766 /// *input = rest;
3767 #[doc = concat!(" ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
3768 /// }
3769 /// ```
3770 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3771 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3772 #[must_use]
3773 #[inline]
3774 pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3775 Self::from_be(Self::from_ne_bytes(bytes))
3776 }
3777
3778 /// Creates an integer value from its representation as a byte array in
3779 /// little endian.
3780 ///
3781 #[doc = $from_xe_bytes_doc]
3782 ///
3783 /// # Examples
3784 ///
3785 /// ```
3786 #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
3787 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3788 /// ```
3789 ///
3790 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3791 ///
3792 /// ```
3793 #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3794 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3795 /// *input = rest;
3796 #[doc = concat!(" ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
3797 /// }
3798 /// ```
3799 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3800 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3801 #[must_use]
3802 #[inline]
3803 pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3804 Self::from_le(Self::from_ne_bytes(bytes))
3805 }
3806
3807 /// Creates an integer value from its memory representation as a byte
3808 /// array in native endianness.
3809 ///
3810 /// As the target platform's native endianness is used, portable code
3811 /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
3812 /// appropriate instead.
3813 ///
3814 /// [`from_be_bytes`]: Self::from_be_bytes
3815 /// [`from_le_bytes`]: Self::from_le_bytes
3816 ///
3817 #[doc = $from_xe_bytes_doc]
3818 ///
3819 /// # Examples
3820 ///
3821 /// ```
3822 #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
3823 #[doc = concat!(" ", $be_bytes)]
3824 /// } else {
3825 #[doc = concat!(" ", $le_bytes)]
3826 /// });
3827 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3828 /// ```
3829 ///
3830 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3831 ///
3832 /// ```
3833 #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3834 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3835 /// *input = rest;
3836 #[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
3837 /// }
3838 /// ```
3839 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3840 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3841 #[allow(unnecessary_transmutes)]
3842 #[must_use]
3843 // SAFETY: const sound because integers are plain old datatypes so we can always
3844 // transmute to them
3845 #[inline]
3846 pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3847 // SAFETY: integers are plain old datatypes so we can always transmute to them
3848 unsafe { mem::transmute(bytes) }
3849 }
3850
3851 /// New code should prefer to use
3852 #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
3853 ///
3854 /// Returns the smallest value that can be represented by this integer type.
3855 #[stable(feature = "rust1", since = "1.0.0")]
3856 #[inline(always)]
3857 #[rustc_promotable]
3858 #[rustc_const_stable(feature = "const_min_value", since = "1.32.0")]
3859 #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
3860 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
3861 pub const fn min_value() -> Self {
3862 Self::MIN
3863 }
3864
3865 /// New code should prefer to use
3866 #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
3867 ///
3868 /// Returns the largest value that can be represented by this integer type.
3869 #[stable(feature = "rust1", since = "1.0.0")]
3870 #[inline(always)]
3871 #[rustc_promotable]
3872 #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
3873 #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
3874 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
3875 pub const fn max_value() -> Self {
3876 Self::MAX
3877 }
3878
3879 /// Clamps this number to a symmetric range centred around zero.
3880 ///
3881 /// The method clamps the number's magnitude (absolute value) to be at most `limit`.
3882 ///
3883 /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more
3884 /// explicit about the intent.
3885 ///
3886 /// # Examples
3887 ///
3888 /// ```
3889 /// #![feature(clamp_magnitude)]
3890 #[doc = concat!("assert_eq!(120", stringify!($SelfT), ".clamp_magnitude(100), 100);")]
3891 #[doc = concat!("assert_eq!(-120", stringify!($SelfT), ".clamp_magnitude(100), -100);")]
3892 #[doc = concat!("assert_eq!(80", stringify!($SelfT), ".clamp_magnitude(100), 80);")]
3893 #[doc = concat!("assert_eq!(-80", stringify!($SelfT), ".clamp_magnitude(100), -80);")]
3894 /// ```
3895 #[must_use = "this returns the clamped value and does not modify the original"]
3896 #[unstable(feature = "clamp_magnitude", issue = "148519")]
3897 #[inline]
3898 pub fn clamp_magnitude(self, limit: $UnsignedT) -> Self {
3899 if let Ok(limit) = core::convert::TryInto::<$SelfT>::try_into(limit) {
3900 self.clamp(-limit, limit)
3901 } else {
3902 self
3903 }
3904 }
3905 }
3906}