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 $UnsignedT).trailing_ones()
168 }
169
170 /// Returns `self` with only the most significant bit set, or `0` if
171 /// the input is `0`.
172 ///
173 /// # Examples
174 ///
175 /// ```
176 #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
177 ///
178 /// assert_eq!(n.isolate_highest_one(), 0b_01000000);
179 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_highest_one(), 0);")]
180 /// ```
181 #[stable(feature = "isolate_most_least_significant_one", since = "CURRENT_RUSTC_VERSION")]
182 #[rustc_const_stable(feature = "isolate_most_least_significant_one", since = "CURRENT_RUSTC_VERSION")]
183 #[must_use = "this returns the result of the operation, \
184 without modifying the original"]
185 #[inline(always)]
186 pub const fn isolate_highest_one(self) -> Self {
187 self & (((1 as $SelfT) << (<$SelfT>::BITS - 1)).wrapping_shr(self.leading_zeros()))
188 }
189
190 /// Returns `self` with only the least significant bit set, or `0` if
191 /// the input is `0`.
192 ///
193 /// # Examples
194 ///
195 /// ```
196 #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")]
197 ///
198 /// assert_eq!(n.isolate_lowest_one(), 0b_00000100);
199 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_lowest_one(), 0);")]
200 /// ```
201 #[stable(feature = "isolate_most_least_significant_one", since = "CURRENT_RUSTC_VERSION")]
202 #[rustc_const_stable(feature = "isolate_most_least_significant_one", since = "CURRENT_RUSTC_VERSION")]
203 #[must_use = "this returns the result of the operation, \
204 without modifying the original"]
205 #[inline(always)]
206 pub const fn isolate_lowest_one(self) -> Self {
207 self & self.wrapping_neg()
208 }
209
210 /// Returns the index of the highest bit set to one in `self`, or `None`
211 /// if `self` is `0`.
212 ///
213 /// # Examples
214 ///
215 /// ```
216 #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".highest_one(), None);")]
217 #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".highest_one(), Some(0));")]
218 #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".highest_one(), Some(4));")]
219 #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".highest_one(), Some(4));")]
220 /// ```
221 #[stable(feature = "int_lowest_highest_one", since = "CURRENT_RUSTC_VERSION")]
222 #[rustc_const_stable(feature = "int_lowest_highest_one", since = "CURRENT_RUSTC_VERSION")]
223 #[must_use = "this returns the result of the operation, \
224 without modifying the original"]
225 #[inline(always)]
226 pub const fn highest_one(self) -> Option<u32> {
227 (self as $UnsignedT).highest_one()
228 }
229
230 /// Returns the index of the lowest bit set to one in `self`, or `None`
231 /// if `self` is `0`.
232 ///
233 /// # Examples
234 ///
235 /// ```
236 #[doc = concat!("assert_eq!(0b0_", stringify!($SelfT), ".lowest_one(), None);")]
237 #[doc = concat!("assert_eq!(0b1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
238 #[doc = concat!("assert_eq!(0b1_0000_", stringify!($SelfT), ".lowest_one(), Some(4));")]
239 #[doc = concat!("assert_eq!(0b1_1111_", stringify!($SelfT), ".lowest_one(), Some(0));")]
240 /// ```
241 #[stable(feature = "int_lowest_highest_one", since = "CURRENT_RUSTC_VERSION")]
242 #[rustc_const_stable(feature = "int_lowest_highest_one", since = "CURRENT_RUSTC_VERSION")]
243 #[must_use = "this returns the result of the operation, \
244 without modifying the original"]
245 #[inline(always)]
246 pub const fn lowest_one(self) -> Option<u32> {
247 (self as $UnsignedT).lowest_one()
248 }
249
250 /// Returns the bit pattern of `self` reinterpreted as an unsigned integer of the same size.
251 ///
252 /// This produces the same result as an `as` cast, but ensures that the bit-width remains
253 /// the same.
254 ///
255 /// # Examples
256 ///
257 /// ```
258 #[doc = concat!("let n = -1", stringify!($SelfT), ";")]
259 ///
260 #[doc = concat!("assert_eq!(n.cast_unsigned(), ", stringify!($UnsignedT), "::MAX);")]
261 /// ```
262 #[stable(feature = "integer_sign_cast", since = "1.87.0")]
263 #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")]
264 #[must_use = "this returns the result of the operation, \
265 without modifying the original"]
266 #[inline(always)]
267 pub const fn cast_unsigned(self) -> $UnsignedT {
268 self as $UnsignedT
269 }
270
271 /// Shifts the bits to the left by a specified amount, `n`,
272 /// wrapping the truncated bits to the end of the resulting integer.
273 ///
274 /// `rotate_left(n)` is equivalent to applying `rotate_left(1)` a total of `n` times. In
275 /// particular, a rotation by the number of bits in `self` returns the input value
276 /// unchanged.
277 ///
278 /// Please note this isn't the same operation as the `<<` shifting operator!
279 ///
280 /// # Examples
281 ///
282 /// ```
283 #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
284 #[doc = concat!("let m = ", $rot_result, ";")]
285 ///
286 #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
287 #[doc = concat!("assert_eq!(n.rotate_left(1024), n);")]
288 /// ```
289 #[stable(feature = "rust1", since = "1.0.0")]
290 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
291 #[must_use = "this returns the result of the operation, \
292 without modifying the original"]
293 #[inline(always)]
294 pub const fn rotate_left(self, n: u32) -> Self {
295 (self as $UnsignedT).rotate_left(n) as Self
296 }
297
298 /// Shifts the bits to the right by a specified amount, `n`,
299 /// wrapping the truncated bits to the beginning of the resulting
300 /// integer.
301 ///
302 /// `rotate_right(n)` is equivalent to applying `rotate_right(1)` a total of `n` times. In
303 /// particular, a rotation by the number of bits in `self` returns the input value
304 /// unchanged.
305 ///
306 /// Please note this isn't the same operation as the `>>` shifting operator!
307 ///
308 /// # Examples
309 ///
310 /// ```
311 #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
312 #[doc = concat!("let m = ", $rot_op, ";")]
313 ///
314 #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
315 #[doc = concat!("assert_eq!(n.rotate_right(1024), n);")]
316 /// ```
317 #[stable(feature = "rust1", since = "1.0.0")]
318 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
319 #[must_use = "this returns the result of the operation, \
320 without modifying the original"]
321 #[inline(always)]
322 pub const fn rotate_right(self, n: u32) -> Self {
323 (self as $UnsignedT).rotate_right(n) as Self
324 }
325
326 /// Reverses the byte order of the integer.
327 ///
328 /// # Examples
329 ///
330 /// ```
331 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
332 ///
333 /// let m = n.swap_bytes();
334 ///
335 #[doc = concat!("assert_eq!(m, ", $swapped, ");")]
336 /// ```
337 #[stable(feature = "rust1", since = "1.0.0")]
338 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
339 #[must_use = "this returns the result of the operation, \
340 without modifying the original"]
341 #[inline(always)]
342 pub const fn swap_bytes(self) -> Self {
343 (self as $UnsignedT).swap_bytes() as Self
344 }
345
346 /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
347 /// second least-significant bit becomes second most-significant bit, etc.
348 ///
349 /// # Examples
350 ///
351 /// ```
352 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
353 /// let m = n.reverse_bits();
354 ///
355 #[doc = concat!("assert_eq!(m, ", $reversed, ");")]
356 #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
357 /// ```
358 #[stable(feature = "reverse_bits", since = "1.37.0")]
359 #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
360 #[must_use = "this returns the result of the operation, \
361 without modifying the original"]
362 #[inline(always)]
363 pub const fn reverse_bits(self) -> Self {
364 (self as $UnsignedT).reverse_bits() as Self
365 }
366
367 /// Converts an integer from big endian to the target's endianness.
368 ///
369 /// On big endian this is a no-op. On little endian the bytes are swapped.
370 ///
371 /// See also [from_be_bytes()](Self::from_be_bytes).
372 ///
373 /// # Examples
374 ///
375 /// ```
376 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
377 ///
378 /// if cfg!(target_endian = "big") {
379 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
380 /// } else {
381 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
382 /// }
383 /// ```
384 #[stable(feature = "rust1", since = "1.0.0")]
385 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
386 #[must_use]
387 #[inline]
388 pub const fn from_be(x: Self) -> Self {
389 #[cfg(target_endian = "big")]
390 {
391 x
392 }
393 #[cfg(not(target_endian = "big"))]
394 {
395 x.swap_bytes()
396 }
397 }
398
399 /// Converts an integer from little endian to the target's endianness.
400 ///
401 /// On little endian this is a no-op. On big endian the bytes are swapped.
402 ///
403 /// See also [from_le_bytes()](Self::from_le_bytes).
404 ///
405 /// # Examples
406 ///
407 /// ```
408 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
409 ///
410 /// if cfg!(target_endian = "little") {
411 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
412 /// } else {
413 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
414 /// }
415 /// ```
416 #[stable(feature = "rust1", since = "1.0.0")]
417 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
418 #[must_use]
419 #[inline]
420 pub const fn from_le(x: Self) -> Self {
421 #[cfg(target_endian = "little")]
422 {
423 x
424 }
425 #[cfg(not(target_endian = "little"))]
426 {
427 x.swap_bytes()
428 }
429 }
430
431 /// Swaps bytes of `self` on little endian targets.
432 ///
433 /// On big endian this is a no-op.
434 ///
435 /// The returned value has the same type as `self`, and will be interpreted
436 /// as (a potentially different) value of a native-endian
437 #[doc = concat!("`", stringify!($SelfT), "`.")]
438 ///
439 /// See [`to_be_bytes()`](Self::to_be_bytes) for a type-safe alternative.
440 ///
441 /// # Examples
442 ///
443 /// ```
444 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
445 ///
446 /// if cfg!(target_endian = "big") {
447 /// assert_eq!(n.to_be(), n)
448 /// } else {
449 /// assert_eq!(n.to_be(), n.swap_bytes())
450 /// }
451 /// ```
452 #[stable(feature = "rust1", since = "1.0.0")]
453 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
454 #[must_use = "this returns the result of the operation, \
455 without modifying the original"]
456 #[inline]
457 pub const fn to_be(self) -> Self { // or not to be?
458 #[cfg(target_endian = "big")]
459 {
460 self
461 }
462 #[cfg(not(target_endian = "big"))]
463 {
464 self.swap_bytes()
465 }
466 }
467
468 /// Swaps bytes of `self` on big endian targets.
469 ///
470 /// On little endian this is a no-op.
471 ///
472 /// The returned value has the same type as `self`, and will be interpreted
473 /// as (a potentially different) value of a native-endian
474 #[doc = concat!("`", stringify!($SelfT), "`.")]
475 ///
476 /// See [`to_le_bytes()`](Self::to_le_bytes) for a type-safe alternative.
477 ///
478 /// # Examples
479 ///
480 /// ```
481 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
482 ///
483 /// if cfg!(target_endian = "little") {
484 /// assert_eq!(n.to_le(), n)
485 /// } else {
486 /// assert_eq!(n.to_le(), n.swap_bytes())
487 /// }
488 /// ```
489 #[stable(feature = "rust1", since = "1.0.0")]
490 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
491 #[must_use = "this returns the result of the operation, \
492 without modifying the original"]
493 #[inline]
494 pub const fn to_le(self) -> Self {
495 #[cfg(target_endian = "little")]
496 {
497 self
498 }
499 #[cfg(not(target_endian = "little"))]
500 {
501 self.swap_bytes()
502 }
503 }
504
505 /// Checked integer addition. Computes `self + rhs`, returning `None`
506 /// if overflow occurred.
507 ///
508 /// # Examples
509 ///
510 /// ```
511 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), Some(", stringify!($SelfT), "::MAX - 1));")]
512 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
513 /// ```
514 #[stable(feature = "rust1", since = "1.0.0")]
515 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
516 #[must_use = "this returns the result of the operation, \
517 without modifying the original"]
518 #[inline]
519 pub const fn checked_add(self, rhs: Self) -> Option<Self> {
520 let (a, b) = self.overflowing_add(rhs);
521 if intrinsics::unlikely(b) { None } else { Some(a) }
522 }
523
524 /// Strict integer addition. Computes `self + rhs`, panicking
525 /// if overflow occurred.
526 ///
527 /// # Panics
528 ///
529 /// ## Overflow behavior
530 ///
531 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
532 ///
533 /// # Examples
534 ///
535 /// ```
536 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
537 /// ```
538 ///
539 /// The following panics because of overflow:
540 ///
541 /// ```should_panic
542 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
543 /// ```
544 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
545 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
546 #[must_use = "this returns the result of the operation, \
547 without modifying the original"]
548 #[inline]
549 #[track_caller]
550 pub const fn strict_add(self, rhs: Self) -> Self {
551 let (a, b) = self.overflowing_add(rhs);
552 if b { imp::overflow_panic::add() } else { a }
553 }
554
555 /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
556 /// cannot occur.
557 ///
558 /// Calling `x.unchecked_add(y)` is semantically equivalent to calling
559 /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
560 ///
561 /// If you're just trying to avoid the panic in debug mode, then **do not**
562 /// use this. Instead, you're looking for [`wrapping_add`].
563 ///
564 /// # Safety
565 ///
566 /// This results in undefined behavior when
567 #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
568 /// i.e. when [`checked_add`] would return `None`.
569 ///
570 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
571 #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
572 #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
573 #[stable(feature = "unchecked_math", since = "1.79.0")]
574 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
575 #[must_use = "this returns the result of the operation, \
576 without modifying the original"]
577 #[inline(always)]
578 #[track_caller]
579 pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
580 assert_unsafe_precondition!(
581 check_language_ub,
582 concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
583 (
584 lhs: $SelfT = self,
585 rhs: $SelfT = rhs,
586 ) => !lhs.overflowing_add(rhs).1,
587 );
588
589 // SAFETY: this is guaranteed to be safe by the caller.
590 unsafe {
591 intrinsics::unchecked_add(self, rhs)
592 }
593 }
594
595 /// Checked addition with an unsigned integer. Computes `self + rhs`,
596 /// returning `None` if overflow occurred.
597 ///
598 /// # Examples
599 ///
600 /// ```
601 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_unsigned(2), Some(3));")]
602 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_unsigned(3), None);")]
603 /// ```
604 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
605 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
606 #[must_use = "this returns the result of the operation, \
607 without modifying the original"]
608 #[inline]
609 pub const fn checked_add_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
610 let (a, b) = self.overflowing_add_unsigned(rhs);
611 if intrinsics::unlikely(b) { None } else { Some(a) }
612 }
613
614 /// Strict addition with an unsigned integer. Computes `self + rhs`,
615 /// panicking if overflow occurred.
616 ///
617 /// # Panics
618 ///
619 /// ## Overflow behavior
620 ///
621 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
622 ///
623 /// # Examples
624 ///
625 /// ```
626 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_unsigned(2), 3);")]
627 /// ```
628 ///
629 /// The following panics because of overflow:
630 ///
631 /// ```should_panic
632 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_unsigned(3);")]
633 /// ```
634 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
635 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
636 #[must_use = "this returns the result of the operation, \
637 without modifying the original"]
638 #[inline]
639 #[track_caller]
640 pub const fn strict_add_unsigned(self, rhs: $UnsignedT) -> Self {
641 let (a, b) = self.overflowing_add_unsigned(rhs);
642 if b { imp::overflow_panic::add() } else { a }
643 }
644
645 /// Checked integer subtraction. Computes `self - rhs`, returning `None` if
646 /// overflow occurred.
647 ///
648 /// # Examples
649 ///
650 /// ```
651 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(1), Some(", stringify!($SelfT), "::MIN + 1));")]
652 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(3), None);")]
653 /// ```
654 #[stable(feature = "rust1", since = "1.0.0")]
655 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
656 #[must_use = "this returns the result of the operation, \
657 without modifying the original"]
658 #[inline]
659 pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
660 let (a, b) = self.overflowing_sub(rhs);
661 if intrinsics::unlikely(b) { None } else { Some(a) }
662 }
663
664 /// Strict integer subtraction. Computes `self - rhs`, panicking if
665 /// overflow occurred.
666 ///
667 /// # Panics
668 ///
669 /// ## Overflow behavior
670 ///
671 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
672 ///
673 /// # Examples
674 ///
675 /// ```
676 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).strict_sub(1), ", stringify!($SelfT), "::MIN + 1);")]
677 /// ```
678 ///
679 /// The following panics because of overflow:
680 ///
681 /// ```should_panic
682 #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub(3);")]
683 /// ```
684 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
685 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
686 #[must_use = "this returns the result of the operation, \
687 without modifying the original"]
688 #[inline]
689 #[track_caller]
690 pub const fn strict_sub(self, rhs: Self) -> Self {
691 let (a, b) = self.overflowing_sub(rhs);
692 if b { imp::overflow_panic::sub() } else { a }
693 }
694
695 /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
696 /// cannot occur.
697 ///
698 /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
699 /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
700 ///
701 /// If you're just trying to avoid the panic in debug mode, then **do not**
702 /// use this. Instead, you're looking for [`wrapping_sub`].
703 ///
704 /// # Safety
705 ///
706 /// This results in undefined behavior when
707 #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
708 /// i.e. when [`checked_sub`] would return `None`.
709 ///
710 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
711 #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
712 #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
713 #[stable(feature = "unchecked_math", since = "1.79.0")]
714 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
715 #[must_use = "this returns the result of the operation, \
716 without modifying the original"]
717 #[inline(always)]
718 #[track_caller]
719 pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
720 assert_unsafe_precondition!(
721 check_language_ub,
722 concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
723 (
724 lhs: $SelfT = self,
725 rhs: $SelfT = rhs,
726 ) => !lhs.overflowing_sub(rhs).1,
727 );
728
729 // SAFETY: this is guaranteed to be safe by the caller.
730 unsafe {
731 intrinsics::unchecked_sub(self, rhs)
732 }
733 }
734
735 /// Checked subtraction with an unsigned integer. Computes `self - rhs`,
736 /// returning `None` if overflow occurred.
737 ///
738 /// # Examples
739 ///
740 /// ```
741 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_unsigned(2), Some(-1));")]
742 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub_unsigned(3), None);")]
743 /// ```
744 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
745 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
746 #[must_use = "this returns the result of the operation, \
747 without modifying the original"]
748 #[inline]
749 pub const fn checked_sub_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
750 let (a, b) = self.overflowing_sub_unsigned(rhs);
751 if intrinsics::unlikely(b) { None } else { Some(a) }
752 }
753
754 /// Strict subtraction with an unsigned integer. Computes `self - rhs`,
755 /// panicking if overflow occurred.
756 ///
757 /// # Panics
758 ///
759 /// ## Overflow behavior
760 ///
761 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
762 ///
763 /// # Examples
764 ///
765 /// ```
766 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub_unsigned(2), -1);")]
767 /// ```
768 ///
769 /// The following panics because of overflow:
770 ///
771 /// ```should_panic
772 #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub_unsigned(3);")]
773 /// ```
774 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
775 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
776 #[must_use = "this returns the result of the operation, \
777 without modifying the original"]
778 #[inline]
779 #[track_caller]
780 pub const fn strict_sub_unsigned(self, rhs: $UnsignedT) -> Self {
781 let (a, b) = self.overflowing_sub_unsigned(rhs);
782 if b { imp::overflow_panic::sub() } else { a }
783 }
784
785 /// Checked integer multiplication. Computes `self * rhs`, returning `None` if
786 /// overflow occurred.
787 ///
788 /// # Examples
789 ///
790 /// ```
791 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(1), Some(", stringify!($SelfT), "::MAX));")]
792 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
793 /// ```
794 #[stable(feature = "rust1", since = "1.0.0")]
795 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
796 #[must_use = "this returns the result of the operation, \
797 without modifying the original"]
798 #[inline]
799 pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
800 let (a, b) = self.overflowing_mul(rhs);
801 if intrinsics::unlikely(b) { None } else { Some(a) }
802 }
803
804 /// Strict integer multiplication. Computes `self * rhs`, panicking if
805 /// overflow occurred.
806 ///
807 /// # Panics
808 ///
809 /// ## Overflow behavior
810 ///
811 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
812 ///
813 /// # Examples
814 ///
815 /// ```
816 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.strict_mul(1), ", stringify!($SelfT), "::MAX);")]
817 /// ```
818 ///
819 /// The following panics because of overflow:
820 ///
821 /// ``` should_panic
822 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
823 /// ```
824 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
825 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
826 #[must_use = "this returns the result of the operation, \
827 without modifying the original"]
828 #[inline]
829 #[track_caller]
830 pub const fn strict_mul(self, rhs: Self) -> Self {
831 let (a, b) = self.overflowing_mul(rhs);
832 if b { imp::overflow_panic::mul() } else { a }
833 }
834
835 /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
836 /// cannot occur.
837 ///
838 /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
839 /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
840 ///
841 /// If you're just trying to avoid the panic in debug mode, then **do not**
842 /// use this. Instead, you're looking for [`wrapping_mul`].
843 ///
844 /// # Safety
845 ///
846 /// This results in undefined behavior when
847 #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
848 /// i.e. when [`checked_mul`] would return `None`.
849 ///
850 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
851 #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
852 #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
853 #[stable(feature = "unchecked_math", since = "1.79.0")]
854 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
855 #[must_use = "this returns the result of the operation, \
856 without modifying the original"]
857 #[inline(always)]
858 #[track_caller]
859 pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
860 assert_unsafe_precondition!(
861 check_language_ub,
862 concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
863 (
864 lhs: $SelfT = self,
865 rhs: $SelfT = rhs,
866 ) => !lhs.overflowing_mul(rhs).1,
867 );
868
869 // SAFETY: this is guaranteed to be safe by the caller.
870 unsafe {
871 intrinsics::unchecked_mul(self, rhs)
872 }
873 }
874
875 /// Checked integer division. Computes `self / rhs`, returning `None` if `rhs == 0`
876 /// or the division results in overflow.
877 ///
878 /// # Examples
879 ///
880 /// ```
881 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div(-1), Some(", stringify!($Max), "));")]
882 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div(-1), None);")]
883 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div(0), None);")]
884 /// ```
885 #[stable(feature = "rust1", since = "1.0.0")]
886 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
887 #[must_use = "this returns the result of the operation, \
888 without modifying the original"]
889 #[inline]
890 pub const fn checked_div(self, rhs: Self) -> Option<Self> {
891 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
892 None
893 } else {
894 // SAFETY: div by zero and by INT_MIN have been checked above
895 Some(unsafe { intrinsics::unchecked_div(self, rhs) })
896 }
897 }
898
899 /// Strict integer division. Computes `self / rhs`, panicking
900 /// if overflow occurred.
901 ///
902 /// # Panics
903 ///
904 /// This function will panic if `rhs` is zero.
905 ///
906 /// ## Overflow behavior
907 ///
908 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
909 ///
910 /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
911 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
912 /// that is too large to represent in the type.
913 ///
914 /// # Examples
915 ///
916 /// ```
917 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).strict_div(-1), ", stringify!($Max), ");")]
918 /// ```
919 ///
920 /// The following panics because of overflow:
921 ///
922 /// ```should_panic
923 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_div(-1);")]
924 /// ```
925 ///
926 /// The following panics because of division by zero:
927 ///
928 /// ```should_panic
929 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
930 /// ```
931 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
932 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
933 #[must_use = "this returns the result of the operation, \
934 without modifying the original"]
935 #[inline]
936 #[track_caller]
937 pub const fn strict_div(self, rhs: Self) -> Self {
938 let (a, b) = self.overflowing_div(rhs);
939 if b { imp::overflow_panic::div() } else { a }
940 }
941
942 /// Checked Euclidean division. Computes `self.div_euclid(rhs)`,
943 /// returning `None` if `rhs == 0` or the division results in overflow.
944 ///
945 /// # Examples
946 ///
947 /// ```
948 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div_euclid(-1), Some(", stringify!($Max), "));")]
949 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div_euclid(-1), None);")]
950 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div_euclid(0), None);")]
951 /// ```
952 #[stable(feature = "euclidean_division", since = "1.38.0")]
953 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
954 #[must_use = "this returns the result of the operation, \
955 without modifying the original"]
956 #[inline]
957 pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
958 // Using `&` helps LLVM see that it is the same check made in division.
959 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
960 None
961 } else {
962 Some(self.div_euclid(rhs))
963 }
964 }
965
966 /// Strict Euclidean division. Computes `self.div_euclid(rhs)`, panicking
967 /// if overflow occurred.
968 ///
969 /// # Panics
970 ///
971 /// This function will panic if `rhs` is zero.
972 ///
973 /// ## Overflow behavior
974 ///
975 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
976 ///
977 /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
978 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
979 /// that is too large to represent in the type.
980 ///
981 /// # Examples
982 ///
983 /// ```
984 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).strict_div_euclid(-1), ", stringify!($Max), ");")]
985 /// ```
986 ///
987 /// The following panics because of overflow:
988 ///
989 /// ```should_panic
990 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_div_euclid(-1);")]
991 /// ```
992 ///
993 /// The following panics because of division by zero:
994 ///
995 /// ```should_panic
996 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
997 /// ```
998 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
999 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1000 #[must_use = "this returns the result of the operation, \
1001 without modifying the original"]
1002 #[inline]
1003 #[track_caller]
1004 pub const fn strict_div_euclid(self, rhs: Self) -> Self {
1005 let (a, b) = self.overflowing_div_euclid(rhs);
1006 if b { imp::overflow_panic::div() } else { a }
1007 }
1008
1009 /// Checked integer division without remainder. Computes `self / rhs`,
1010 /// returning `None` if `rhs == 0`, the division results in overflow,
1011 /// or `self % rhs != 0`.
1012 ///
1013 /// # Examples
1014 ///
1015 /// ```
1016 /// #![feature(exact_div)]
1017 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div_exact(-1), Some(", stringify!($Max), "));")]
1018 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").checked_div_exact(2), None);")]
1019 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div_exact(-1), None);")]
1020 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div_exact(0), None);")]
1021 /// ```
1022 #[unstable(
1023 feature = "exact_div",
1024 issue = "139911",
1025 )]
1026 #[must_use = "this returns the result of the operation, \
1027 without modifying the original"]
1028 #[inline]
1029 pub const fn checked_div_exact(self, rhs: Self) -> Option<Self> {
1030 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
1031 None
1032 } else {
1033 // SAFETY: division by zero and overflow are checked above
1034 unsafe {
1035 if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) {
1036 None
1037 } else {
1038 Some(intrinsics::exact_div(self, rhs))
1039 }
1040 }
1041 }
1042 }
1043
1044 /// Integer division without remainder. Computes `self / rhs`, returning `None` if `self % rhs != 0`.
1045 ///
1046 /// # Panics
1047 ///
1048 /// This function will panic if `rhs == 0`.
1049 ///
1050 /// ## Overflow behavior
1051 ///
1052 /// On overflow, this function will panic if overflow checks are enabled (default in debug
1053 /// mode) and wrap if overflow checks are disabled (default in release mode).
1054 ///
1055 /// # Examples
1056 ///
1057 /// ```
1058 /// #![feature(exact_div)]
1059 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(2), Some(32));")]
1060 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(32), Some(2));")]
1061 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).div_exact(-1), Some(", stringify!($Max), "));")]
1062 #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".div_exact(2), None);")]
1063 /// ```
1064 /// ```should_panic
1065 /// #![feature(exact_div)]
1066 #[doc = concat!("let _ = 64", stringify!($SelfT),".div_exact(0);")]
1067 /// ```
1068 /// ```should_panic
1069 /// #![feature(exact_div)]
1070 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.div_exact(-1);")]
1071 /// ```
1072 #[unstable(
1073 feature = "exact_div",
1074 issue = "139911",
1075 )]
1076 #[must_use = "this returns the result of the operation, \
1077 without modifying the original"]
1078 #[inline]
1079 #[rustc_inherit_overflow_checks]
1080 pub const fn div_exact(self, rhs: Self) -> Option<Self> {
1081 if self % rhs != 0 {
1082 None
1083 } else {
1084 Some(self / rhs)
1085 }
1086 }
1087
1088 /// Unchecked integer division without remainder. Computes `self / rhs`.
1089 ///
1090 /// # Safety
1091 ///
1092 /// This results in undefined behavior when `rhs == 0`, `self % rhs != 0`, or
1093 #[doc = concat!("`self == ", stringify!($SelfT), "::MIN && rhs == -1`,")]
1094 /// i.e. when [`checked_div_exact`](Self::checked_div_exact) would return `None`.
1095 #[unstable(
1096 feature = "exact_div",
1097 issue = "139911",
1098 )]
1099 #[must_use = "this returns the result of the operation, \
1100 without modifying the original"]
1101 #[inline]
1102 pub const unsafe fn unchecked_div_exact(self, rhs: Self) -> Self {
1103 assert_unsafe_precondition!(
1104 check_language_ub,
1105 concat!(stringify!($SelfT), "::unchecked_div_exact cannot overflow, divide by zero, or leave a remainder"),
1106 (
1107 lhs: $SelfT = self,
1108 rhs: $SelfT = rhs,
1109 ) => rhs > 0 && lhs % rhs == 0 && (lhs != <$SelfT>::MIN || rhs != -1),
1110 );
1111 // SAFETY: Same precondition
1112 unsafe { intrinsics::exact_div(self, rhs) }
1113 }
1114
1115 /// Checked integer remainder. Computes `self % rhs`, returning `None` if
1116 /// `rhs == 0` or the division results in overflow.
1117 ///
1118 /// # Examples
1119 ///
1120 /// ```
1121 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
1122 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
1123 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_rem(-1), None);")]
1124 /// ```
1125 #[stable(feature = "wrapping", since = "1.7.0")]
1126 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1127 #[must_use = "this returns the result of the operation, \
1128 without modifying the original"]
1129 #[inline]
1130 pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
1131 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
1132 None
1133 } else {
1134 // SAFETY: div by zero and by INT_MIN have been checked above
1135 Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
1136 }
1137 }
1138
1139 /// Strict integer remainder. Computes `self % rhs`, panicking if
1140 /// the division results in overflow.
1141 ///
1142 /// # Panics
1143 ///
1144 /// This function will panic if `rhs` is zero.
1145 ///
1146 /// ## Overflow behavior
1147 ///
1148 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1149 ///
1150 /// The only case where such an overflow can occur is `x % y` for `MIN / -1` on a
1151 /// signed type (where `MIN` is the negative minimal value), which is invalid due to implementation artifacts.
1152 ///
1153 /// # Examples
1154 ///
1155 /// ```
1156 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_rem(2), 1);")]
1157 /// ```
1158 ///
1159 /// The following panics because of division by zero:
1160 ///
1161 /// ```should_panic
1162 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
1163 /// ```
1164 ///
1165 /// The following panics because of overflow:
1166 ///
1167 /// ```should_panic
1168 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem(-1);")]
1169 /// ```
1170 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1171 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1172 #[must_use = "this returns the result of the operation, \
1173 without modifying the original"]
1174 #[inline]
1175 #[track_caller]
1176 pub const fn strict_rem(self, rhs: Self) -> Self {
1177 let (a, b) = self.overflowing_rem(rhs);
1178 if b { imp::overflow_panic::rem() } else { a }
1179 }
1180
1181 /// Checked Euclidean remainder. Computes `self.rem_euclid(rhs)`, returning `None`
1182 /// if `rhs == 0` or the division results in overflow.
1183 ///
1184 /// # Examples
1185 ///
1186 /// ```
1187 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
1188 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
1189 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_rem_euclid(-1), None);")]
1190 /// ```
1191 #[stable(feature = "euclidean_division", since = "1.38.0")]
1192 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1193 #[must_use = "this returns the result of the operation, \
1194 without modifying the original"]
1195 #[inline]
1196 pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
1197 // Using `&` helps LLVM see that it is the same check made in division.
1198 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
1199 None
1200 } else {
1201 Some(self.rem_euclid(rhs))
1202 }
1203 }
1204
1205 /// Strict Euclidean remainder. Computes `self.rem_euclid(rhs)`, panicking if
1206 /// the division results in overflow.
1207 ///
1208 /// # Panics
1209 ///
1210 /// This function will panic if `rhs` is zero.
1211 ///
1212 /// ## Overflow behavior
1213 ///
1214 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1215 ///
1216 /// The only case where such an overflow can occur is `x % y` for `MIN / -1` on a
1217 /// signed type (where `MIN` is the negative minimal value), which is invalid due to implementation artifacts.
1218 ///
1219 /// # Examples
1220 ///
1221 /// ```
1222 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_rem_euclid(2), 1);")]
1223 /// ```
1224 ///
1225 /// The following panics because of division by zero:
1226 ///
1227 /// ```should_panic
1228 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
1229 /// ```
1230 ///
1231 /// The following panics because of overflow:
1232 ///
1233 /// ```should_panic
1234 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem_euclid(-1);")]
1235 /// ```
1236 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1237 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1238 #[must_use = "this returns the result of the operation, \
1239 without modifying the original"]
1240 #[inline]
1241 #[track_caller]
1242 pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
1243 let (a, b) = self.overflowing_rem_euclid(rhs);
1244 if b { imp::overflow_panic::rem() } else { a }
1245 }
1246
1247 /// Checked negation. Computes `-self`, returning `None` if `self == MIN`.
1248 ///
1249 /// # Examples
1250 ///
1251 /// ```
1252 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_neg(), Some(-5));")]
1253 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_neg(), None);")]
1254 /// ```
1255 #[stable(feature = "wrapping", since = "1.7.0")]
1256 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1257 #[must_use = "this returns the result of the operation, \
1258 without modifying the original"]
1259 #[inline]
1260 pub const fn checked_neg(self) -> Option<Self> {
1261 let (a, b) = self.overflowing_neg();
1262 if intrinsics::unlikely(b) { None } else { Some(a) }
1263 }
1264
1265 /// Unchecked negation. Computes `-self`, assuming overflow cannot occur.
1266 ///
1267 /// # Safety
1268 ///
1269 /// This results in undefined behavior when
1270 #[doc = concat!("`self == ", stringify!($SelfT), "::MIN`,")]
1271 /// i.e. when [`checked_neg`] would return `None`.
1272 ///
1273 #[doc = concat!("[`checked_neg`]: ", stringify!($SelfT), "::checked_neg")]
1274 #[stable(feature = "unchecked_neg", since = "1.93.0")]
1275 #[rustc_const_stable(feature = "unchecked_neg", since = "1.93.0")]
1276 #[must_use = "this returns the result of the operation, \
1277 without modifying the original"]
1278 #[inline(always)]
1279 #[track_caller]
1280 pub const unsafe fn unchecked_neg(self) -> Self {
1281 assert_unsafe_precondition!(
1282 check_language_ub,
1283 concat!(stringify!($SelfT), "::unchecked_neg cannot overflow"),
1284 (
1285 lhs: $SelfT = self,
1286 ) => !lhs.overflowing_neg().1,
1287 );
1288
1289 // SAFETY: this is guaranteed to be safe by the caller.
1290 unsafe {
1291 intrinsics::unchecked_sub(0, self)
1292 }
1293 }
1294
1295 /// Strict negation. Computes `-self`, panicking if `self == MIN`.
1296 ///
1297 /// # Panics
1298 ///
1299 /// ## Overflow behavior
1300 ///
1301 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1302 ///
1303 /// # Examples
1304 ///
1305 /// ```
1306 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_neg(), -5);")]
1307 /// ```
1308 ///
1309 /// The following panics because of overflow:
1310 ///
1311 /// ```should_panic
1312 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_neg();")]
1313 /// ```
1314 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1315 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1316 #[must_use = "this returns the result of the operation, \
1317 without modifying the original"]
1318 #[inline]
1319 #[track_caller]
1320 pub const fn strict_neg(self) -> Self {
1321 let (a, b) = self.overflowing_neg();
1322 if b { imp::overflow_panic::neg() } else { a }
1323 }
1324
1325 /// Checked shift left. Computes `self << rhs`, returning `None` if `rhs` is larger
1326 /// than or equal to the number of bits in `self`.
1327 ///
1328 /// # Examples
1329 ///
1330 /// ```
1331 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
1332 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(129), None);")]
1333 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
1334 /// ```
1335 #[stable(feature = "wrapping", since = "1.7.0")]
1336 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1337 #[must_use = "this returns the result of the operation, \
1338 without modifying the original"]
1339 #[inline]
1340 pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
1341 // Not using overflowing_shl as that's a wrapping shift
1342 if rhs < Self::BITS {
1343 // SAFETY: just checked the RHS is in-range
1344 Some(unsafe { self.unchecked_shl(rhs) })
1345 } else {
1346 None
1347 }
1348 }
1349
1350 /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
1351 /// than or equal to the number of bits in `self`.
1352 ///
1353 /// # Panics
1354 ///
1355 /// ## Overflow behavior
1356 ///
1357 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1358 ///
1359 /// # Examples
1360 ///
1361 /// ```
1362 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
1363 /// ```
1364 ///
1365 /// The following panics because of overflow:
1366 ///
1367 /// ```should_panic
1368 #[doc = concat!("let _ = 0x1", stringify!($SelfT), ".strict_shl(129);")]
1369 /// ```
1370 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1371 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1372 #[must_use = "this returns the result of the operation, \
1373 without modifying the original"]
1374 #[inline]
1375 #[track_caller]
1376 pub const fn strict_shl(self, rhs: u32) -> Self {
1377 let (a, b) = self.overflowing_shl(rhs);
1378 if b { imp::overflow_panic::shl() } else { a }
1379 }
1380
1381 /// Unchecked shift left. Computes `self << rhs`, assuming that
1382 /// `rhs` is less than the number of bits in `self`.
1383 ///
1384 /// # Safety
1385 ///
1386 /// This results in undefined behavior if `rhs` is larger than
1387 /// or equal to the number of bits in `self`,
1388 /// i.e. when [`checked_shl`] would return `None`.
1389 ///
1390 #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
1391 #[stable(feature = "unchecked_shifts", since = "1.93.0")]
1392 #[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
1393 #[must_use = "this returns the result of the operation, \
1394 without modifying the original"]
1395 #[inline(always)]
1396 #[track_caller]
1397 pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
1398 assert_unsafe_precondition!(
1399 check_language_ub,
1400 concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
1401 (
1402 rhs: u32 = rhs,
1403 ) => rhs < <$ActualT>::BITS,
1404 );
1405
1406 // SAFETY: this is guaranteed to be safe by the caller.
1407 unsafe {
1408 intrinsics::unchecked_shl(self, rhs)
1409 }
1410 }
1411
1412 /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`.
1413 ///
1414 /// If `rhs` is larger or equal to the number of bits in `self`,
1415 /// the entire value is shifted out, and `0` is returned.
1416 ///
1417 /// # Examples
1418 ///
1419 /// ```
1420 #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
1421 #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(129), 0);")]
1422 #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(0), 0b101);")]
1423 #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(1), 0b1010);")]
1424 #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(2), 0b10100);")]
1425 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(", stringify!($BITS), "), 0);")]
1426 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(1).unbounded_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
1427 #[doc = concat!("assert_eq!((-13_", stringify!($SelfT), ").unbounded_shl(", stringify!($BITS), "), 0);")]
1428 #[doc = concat!("assert_eq!((-13_", stringify!($SelfT), ").unbounded_shl(1).unbounded_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
1429 /// ```
1430 #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1431 #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1432 #[must_use = "this returns the result of the operation, \
1433 without modifying the original"]
1434 #[inline]
1435 pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
1436 if rhs < Self::BITS {
1437 // SAFETY:
1438 // rhs is just checked to be in-range above
1439 unsafe { self.unchecked_shl(rhs) }
1440 } else {
1441 0
1442 }
1443 }
1444
1445 /// Exact shift left. Computes `self << rhs` as long as it can be reversed losslessly.
1446 ///
1447 /// Returns `None` if any bits that would be shifted out differ from the resulting sign bit
1448 /// or if `rhs` >=
1449 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1450 /// Otherwise, returns `Some(self << rhs)`.
1451 ///
1452 /// # Examples
1453 ///
1454 /// ```
1455 /// #![feature(exact_bitshifts)]
1456 ///
1457 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(4), Some(0x10));")]
1458 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(", stringify!($SelfT), "::BITS - 2), Some(1 << ", stringify!($SelfT), "::BITS - 2));")]
1459 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(", stringify!($SelfT), "::BITS - 1), None);")]
1460 #[doc = concat!("assert_eq!((-0x2", stringify!($SelfT), ").shl_exact(", stringify!($SelfT), "::BITS - 2), Some(-0x2 << ", stringify!($SelfT), "::BITS - 2));")]
1461 #[doc = concat!("assert_eq!((-0x2", stringify!($SelfT), ").shl_exact(", stringify!($SelfT), "::BITS - 1), None);")]
1462 /// ```
1463 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1464 #[must_use = "this returns the result of the operation, \
1465 without modifying the original"]
1466 #[inline]
1467 pub const fn shl_exact(self, rhs: u32) -> Option<$SelfT> {
1468 if rhs < self.leading_zeros() || rhs < self.leading_ones() {
1469 // SAFETY: rhs is checked above
1470 Some(unsafe { self.unchecked_shl(rhs) })
1471 } else {
1472 None
1473 }
1474 }
1475
1476 /// Unchecked exact shift left. Computes `self << rhs`, assuming the operation can be
1477 /// losslessly reversed and `rhs` cannot be larger than
1478 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1479 ///
1480 /// # Safety
1481 ///
1482 /// This results in undefined behavior when `rhs >= self.leading_zeros() && rhs >=
1483 /// self.leading_ones()` i.e. when
1484 #[doc = concat!("[`", stringify!($SelfT), "::shl_exact`]")]
1485 /// would return `None`.
1486 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1487 #[must_use = "this returns the result of the operation, \
1488 without modifying the original"]
1489 #[inline]
1490 pub const unsafe fn unchecked_shl_exact(self, rhs: u32) -> $SelfT {
1491 assert_unsafe_precondition!(
1492 check_library_ub,
1493 concat!(stringify!($SelfT), "::unchecked_shl_exact cannot shift out bits that would change the value of the first bit"),
1494 (
1495 zeros: u32 = self.leading_zeros(),
1496 ones: u32 = self.leading_ones(),
1497 rhs: u32 = rhs,
1498 ) => rhs < zeros || rhs < ones,
1499 );
1500
1501 // SAFETY: this is guaranteed to be safe by the caller
1502 unsafe { self.unchecked_shl(rhs) }
1503 }
1504
1505 /// Checked shift right. Computes `self >> rhs`, returning `None` if `rhs` is
1506 /// larger than or equal to the number of bits in `self`.
1507 ///
1508 /// # Examples
1509 ///
1510 /// ```
1511 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
1512 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(128), None);")]
1513 /// ```
1514 #[stable(feature = "wrapping", since = "1.7.0")]
1515 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1516 #[must_use = "this returns the result of the operation, \
1517 without modifying the original"]
1518 #[inline]
1519 pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
1520 // Not using overflowing_shr as that's a wrapping shift
1521 if rhs < Self::BITS {
1522 // SAFETY: just checked the RHS is in-range
1523 Some(unsafe { self.unchecked_shr(rhs) })
1524 } else {
1525 None
1526 }
1527 }
1528
1529 /// Strict shift right. Computes `self >> rhs`, panicking if `rhs` is
1530 /// larger than or equal to the number of bits in `self`.
1531 ///
1532 /// # Panics
1533 ///
1534 /// ## Overflow behavior
1535 ///
1536 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1537 ///
1538 /// # Examples
1539 ///
1540 /// ```
1541 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
1542 /// ```
1543 ///
1544 /// The following panics because of overflow:
1545 ///
1546 /// ```should_panic
1547 #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(128);")]
1548 /// ```
1549 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1550 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1551 #[must_use = "this returns the result of the operation, \
1552 without modifying the original"]
1553 #[inline]
1554 #[track_caller]
1555 pub const fn strict_shr(self, rhs: u32) -> Self {
1556 let (a, b) = self.overflowing_shr(rhs);
1557 if b { imp::overflow_panic::shr() } else { a }
1558 }
1559
1560 /// Unchecked shift right. Computes `self >> rhs`, assuming that
1561 /// `rhs` is less than the number of bits in `self`.
1562 ///
1563 /// # Safety
1564 ///
1565 /// This results in undefined behavior if `rhs` is larger than
1566 /// or equal to the number of bits in `self`,
1567 /// i.e. when [`checked_shr`] would return `None`.
1568 ///
1569 #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
1570 #[stable(feature = "unchecked_shifts", since = "1.93.0")]
1571 #[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
1572 #[must_use = "this returns the result of the operation, \
1573 without modifying the original"]
1574 #[inline(always)]
1575 #[track_caller]
1576 pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
1577 assert_unsafe_precondition!(
1578 check_language_ub,
1579 concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
1580 (
1581 rhs: u32 = rhs,
1582 ) => rhs < <$ActualT>::BITS,
1583 );
1584
1585 // SAFETY: this is guaranteed to be safe by the caller.
1586 unsafe {
1587 intrinsics::unchecked_shr(self, rhs)
1588 }
1589 }
1590
1591 /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`.
1592 ///
1593 /// If `rhs` is larger or equal to the number of bits in `self`,
1594 /// the entire value is shifted out, which yields `0` for a positive number,
1595 /// and `-1` for a negative number.
1596 ///
1597 /// # Examples
1598 ///
1599 /// ```
1600 #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
1601 #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(129), 0);")]
1602 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.unbounded_shr(129), -1);")]
1603 #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(0), 0b1010);")]
1604 #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(1), 0b101);")]
1605 #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(2), 0b10);")]
1606 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(", stringify!($BITS), "), 0);")]
1607 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(1).unbounded_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
1608 #[doc = concat!("assert_eq!((-13_", stringify!($SelfT), ").unbounded_shr(", stringify!($BITS), "), -1);")]
1609 #[doc = concat!("assert_eq!((-13_", stringify!($SelfT), ").unbounded_shr(1).unbounded_shr(", stringify!($BITS_MINUS_ONE), "), -1);")]
1610 /// ```
1611 #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1612 #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1613 #[must_use = "this returns the result of the operation, \
1614 without modifying the original"]
1615 #[inline]
1616 pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
1617 if rhs < Self::BITS {
1618 // SAFETY:
1619 // rhs is just checked to be in-range above
1620 unsafe { self.unchecked_shr(rhs) }
1621 } else {
1622 // A shift by `Self::BITS-1` suffices for signed integers, because the sign bit is copied for each of the shifted bits.
1623
1624 // SAFETY:
1625 // `Self::BITS-1` is guaranteed to be less than `Self::BITS`
1626 unsafe { self.unchecked_shr(Self::BITS - 1) }
1627 }
1628 }
1629
1630 /// Exact shift right. Computes `self >> rhs` as long as it can be reversed losslessly.
1631 ///
1632 /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
1633 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1634 /// Otherwise, returns `Some(self >> rhs)`.
1635 ///
1636 /// # Examples
1637 ///
1638 /// ```
1639 /// #![feature(exact_bitshifts)]
1640 ///
1641 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(4), Some(0x1));")]
1642 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(5), None);")]
1643 /// ```
1644 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1645 #[must_use = "this returns the result of the operation, \
1646 without modifying the original"]
1647 #[inline]
1648 pub const fn shr_exact(self, rhs: u32) -> Option<$SelfT> {
1649 if rhs <= self.trailing_zeros() && rhs < <$SelfT>::BITS {
1650 // SAFETY: rhs is checked above
1651 Some(unsafe { self.unchecked_shr(rhs) })
1652 } else {
1653 None
1654 }
1655 }
1656
1657 /// Unchecked exact shift right. Computes `self >> rhs`, assuming the operation can be
1658 /// losslessly reversed and `rhs` cannot be larger than
1659 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1660 ///
1661 /// # Safety
1662 ///
1663 /// This results in undefined behavior when `rhs > self.trailing_zeros() || rhs >=
1664 #[doc = concat!(stringify!($SelfT), "::BITS`")]
1665 /// i.e. when
1666 #[doc = concat!("[`", stringify!($SelfT), "::shr_exact`]")]
1667 /// would return `None`.
1668 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1669 #[must_use = "this returns the result of the operation, \
1670 without modifying the original"]
1671 #[inline]
1672 pub const unsafe fn unchecked_shr_exact(self, rhs: u32) -> $SelfT {
1673 assert_unsafe_precondition!(
1674 check_library_ub,
1675 concat!(stringify!($SelfT), "::unchecked_shr_exact cannot shift out non-zero bits"),
1676 (
1677 zeros: u32 = self.trailing_zeros(),
1678 bits: u32 = <$SelfT>::BITS,
1679 rhs: u32 = rhs,
1680 ) => rhs <= zeros && rhs < bits,
1681 );
1682
1683 // SAFETY: this is guaranteed to be safe by the caller
1684 unsafe { self.unchecked_shr(rhs) }
1685 }
1686
1687 /// Checked absolute value. Computes `self.abs()`, returning `None` if
1688 /// `self == MIN`.
1689 ///
1690 /// # Examples
1691 ///
1692 /// ```
1693 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").checked_abs(), Some(5));")]
1694 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_abs(), None);")]
1695 /// ```
1696 #[stable(feature = "no_panic_abs", since = "1.13.0")]
1697 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1698 #[must_use = "this returns the result of the operation, \
1699 without modifying the original"]
1700 #[inline]
1701 pub const fn checked_abs(self) -> Option<Self> {
1702 if self.is_negative() {
1703 self.checked_neg()
1704 } else {
1705 Some(self)
1706 }
1707 }
1708
1709 /// Strict absolute value. Computes `self.abs()`, panicking if
1710 /// `self == MIN`.
1711 ///
1712 /// # Panics
1713 ///
1714 /// ## Overflow behavior
1715 ///
1716 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1717 ///
1718 /// # Examples
1719 ///
1720 /// ```
1721 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").strict_abs(), 5);")]
1722 /// ```
1723 ///
1724 /// The following panics because of overflow:
1725 ///
1726 /// ```should_panic
1727 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_abs();")]
1728 /// ```
1729 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1730 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1731 #[must_use = "this returns the result of the operation, \
1732 without modifying the original"]
1733 #[inline]
1734 #[track_caller]
1735 pub const fn strict_abs(self) -> Self {
1736 if self.is_negative() {
1737 self.strict_neg()
1738 } else {
1739 self
1740 }
1741 }
1742
1743 /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
1744 /// overflow occurred.
1745 ///
1746 /// # Examples
1747 ///
1748 /// ```
1749 #[doc = concat!("assert_eq!(8", stringify!($SelfT), ".checked_pow(2), Some(64));")]
1750 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".checked_pow(0), Some(1));")]
1751 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
1752 /// ```
1753
1754 #[stable(feature = "no_panic_pow", since = "1.34.0")]
1755 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
1756 #[must_use = "this returns the result of the operation, \
1757 without modifying the original"]
1758 #[inline]
1759 pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
1760 if exp == 0 {
1761 return Some(1);
1762 }
1763 let mut base = self;
1764 let mut acc: Self = 1;
1765
1766 loop {
1767 if (exp & 1) == 1 {
1768 acc = try_opt!(acc.checked_mul(base));
1769 // since exp!=0, finally the exp must be 1.
1770 if exp == 1 {
1771 return Some(acc);
1772 }
1773 }
1774 exp /= 2;
1775 base = try_opt!(base.checked_mul(base));
1776 }
1777 }
1778
1779 /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
1780 /// overflow occurred.
1781 ///
1782 /// # Panics
1783 ///
1784 /// ## Overflow behavior
1785 ///
1786 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1787 ///
1788 /// # Examples
1789 ///
1790 /// ```
1791 #[doc = concat!("assert_eq!(8", stringify!($SelfT), ".strict_pow(2), 64);")]
1792 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".strict_pow(0), 1);")]
1793 /// ```
1794 ///
1795 /// The following panics because of overflow:
1796 ///
1797 /// ```should_panic
1798 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
1799 /// ```
1800 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1801 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1802 #[must_use = "this returns the result of the operation, \
1803 without modifying the original"]
1804 #[inline]
1805 #[track_caller]
1806 pub const fn strict_pow(self, mut exp: u32) -> Self {
1807 if exp == 0 {
1808 return 1;
1809 }
1810 let mut base = self;
1811 let mut acc: Self = 1;
1812
1813 loop {
1814 if (exp & 1) == 1 {
1815 acc = acc.strict_mul(base);
1816 // since exp!=0, finally the exp must be 1.
1817 if exp == 1 {
1818 return acc;
1819 }
1820 }
1821 exp /= 2;
1822 base = base.strict_mul(base);
1823 }
1824 }
1825
1826 /// Returns the square root of the number, rounded down.
1827 ///
1828 /// Returns `None` if `self` is negative.
1829 ///
1830 /// # Examples
1831 ///
1832 /// ```
1833 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_isqrt(), Some(3));")]
1834 /// ```
1835 #[stable(feature = "isqrt", since = "1.84.0")]
1836 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
1837 #[must_use = "this returns the result of the operation, \
1838 without modifying the original"]
1839 #[inline]
1840 pub const fn checked_isqrt(self) -> Option<Self> {
1841 if self < 0 {
1842 None
1843 } else {
1844 // SAFETY: Input is nonnegative in this `else` branch.
1845 let result = unsafe {
1846 imp::int_sqrt::$ActualT(self as $ActualT) as $SelfT
1847 };
1848
1849 // Inform the optimizer what the range of outputs is. If
1850 // testing `core` crashes with no panic message and a
1851 // `num::int_sqrt::i*` test failed, it's because your edits
1852 // caused these assertions to become false.
1853 //
1854 // SAFETY: Integer square root is a monotonically nondecreasing
1855 // function, which means that increasing the input will never
1856 // cause the output to decrease. Thus, since the input for
1857 // nonnegative signed integers is bounded by
1858 // `[0, <$ActualT>::MAX]`, sqrt(n) will be bounded by
1859 // `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
1860 unsafe {
1861 // SAFETY: `<$ActualT>::MAX` is nonnegative.
1862 const MAX_RESULT: $SelfT = unsafe {
1863 imp::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT
1864 };
1865
1866 crate::hint::assert_unchecked(result >= 0);
1867 crate::hint::assert_unchecked(result <= MAX_RESULT);
1868 }
1869
1870 Some(result)
1871 }
1872 }
1873
1874 /// Saturating integer addition. Computes `self + rhs`, saturating at the numeric
1875 /// bounds instead of overflowing.
1876 ///
1877 /// # Examples
1878 ///
1879 /// ```
1880 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
1881 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(100), ", stringify!($SelfT), "::MAX);")]
1882 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_add(-1), ", stringify!($SelfT), "::MIN);")]
1883 /// ```
1884
1885 #[stable(feature = "rust1", since = "1.0.0")]
1886 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1887 #[must_use = "this returns the result of the operation, \
1888 without modifying the original"]
1889 #[inline(always)]
1890 pub const fn saturating_add(self, rhs: Self) -> Self {
1891 intrinsics::saturating_add(self, rhs)
1892 }
1893
1894 /// Saturating addition with an unsigned integer. Computes `self + rhs`,
1895 /// saturating at the numeric bounds instead of overflowing.
1896 ///
1897 /// # Examples
1898 ///
1899 /// ```
1900 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_unsigned(2), 3);")]
1901 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add_unsigned(100), ", stringify!($SelfT), "::MAX);")]
1902 /// ```
1903 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1904 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1905 #[must_use = "this returns the result of the operation, \
1906 without modifying the original"]
1907 #[inline]
1908 pub const fn saturating_add_unsigned(self, rhs: $UnsignedT) -> Self {
1909 // Overflow can only happen at the upper bound
1910 // We cannot use `unwrap_or` here because it is not `const`
1911 match self.checked_add_unsigned(rhs) {
1912 Some(x) => x,
1913 None => Self::MAX,
1914 }
1915 }
1916
1917 /// Saturating integer subtraction. Computes `self - rhs`, saturating at the
1918 /// numeric bounds instead of overflowing.
1919 ///
1920 /// # Examples
1921 ///
1922 /// ```
1923 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(127), -27);")]
1924 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub(100), ", stringify!($SelfT), "::MIN);")]
1925 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_sub(-1), ", stringify!($SelfT), "::MAX);")]
1926 /// ```
1927 #[stable(feature = "rust1", since = "1.0.0")]
1928 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1929 #[must_use = "this returns the result of the operation, \
1930 without modifying the original"]
1931 #[inline(always)]
1932 pub const fn saturating_sub(self, rhs: Self) -> Self {
1933 intrinsics::saturating_sub(self, rhs)
1934 }
1935
1936 /// Saturating subtraction with an unsigned integer. Computes `self - rhs`,
1937 /// saturating at the numeric bounds instead of overflowing.
1938 ///
1939 /// # Examples
1940 ///
1941 /// ```
1942 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub_unsigned(127), -27);")]
1943 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub_unsigned(100), ", stringify!($SelfT), "::MIN);")]
1944 /// ```
1945 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1946 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1947 #[must_use = "this returns the result of the operation, \
1948 without modifying the original"]
1949 #[inline]
1950 pub const fn saturating_sub_unsigned(self, rhs: $UnsignedT) -> Self {
1951 // Overflow can only happen at the lower bound
1952 // We cannot use `unwrap_or` here because it is not `const`
1953 match self.checked_sub_unsigned(rhs) {
1954 Some(x) => x,
1955 None => Self::MIN,
1956 }
1957 }
1958
1959 /// Saturating integer negation. Computes `-self`, returning `MAX` if `self == MIN`
1960 /// instead of overflowing.
1961 ///
1962 /// # Examples
1963 ///
1964 /// ```
1965 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_neg(), -100);")]
1966 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").saturating_neg(), 100);")]
1967 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_neg(), ", stringify!($SelfT), "::MAX);")]
1968 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_neg(), ", stringify!($SelfT), "::MIN + 1);")]
1969 /// ```
1970
1971 #[stable(feature = "saturating_neg", since = "1.45.0")]
1972 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1973 #[must_use = "this returns the result of the operation, \
1974 without modifying the original"]
1975 #[inline(always)]
1976 pub const fn saturating_neg(self) -> Self {
1977 intrinsics::saturating_sub(0, self)
1978 }
1979
1980 /// Saturating absolute value. Computes `self.abs()`, returning `MAX` if `self ==
1981 /// MIN` instead of overflowing.
1982 ///
1983 /// # Examples
1984 ///
1985 /// ```
1986 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_abs(), 100);")]
1987 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").saturating_abs(), 100);")]
1988 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_abs(), ", stringify!($SelfT), "::MAX);")]
1989 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).saturating_abs(), ", stringify!($SelfT), "::MAX);")]
1990 /// ```
1991
1992 #[stable(feature = "saturating_neg", since = "1.45.0")]
1993 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1994 #[must_use = "this returns the result of the operation, \
1995 without modifying the original"]
1996 #[inline]
1997 pub const fn saturating_abs(self) -> Self {
1998 if self.is_negative() {
1999 self.saturating_neg()
2000 } else {
2001 self
2002 }
2003 }
2004
2005 /// Saturating integer multiplication. Computes `self * rhs`, saturating at the
2006 /// numeric bounds instead of overflowing.
2007 ///
2008 /// # Examples
2009 ///
2010 /// ```
2011 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".saturating_mul(12), 120);")]
2012 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_mul(10), ", stringify!($SelfT), "::MAX);")]
2013 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_mul(10), ", stringify!($SelfT), "::MIN);")]
2014 /// ```
2015 #[stable(feature = "wrapping", since = "1.7.0")]
2016 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2017 #[must_use = "this returns the result of the operation, \
2018 without modifying the original"]
2019 #[inline]
2020 pub const fn saturating_mul(self, rhs: Self) -> Self {
2021 match self.checked_mul(rhs) {
2022 Some(x) => x,
2023 None => if (self < 0) == (rhs < 0) {
2024 Self::MAX
2025 } else {
2026 Self::MIN
2027 }
2028 }
2029 }
2030
2031 /// Saturating integer division. Computes `self / rhs`, saturating at the
2032 /// numeric bounds instead of overflowing.
2033 ///
2034 /// # Panics
2035 ///
2036 /// This function will panic if `rhs` is zero.
2037 ///
2038 /// # Examples
2039 ///
2040 /// ```
2041 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
2042 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_div(-1), ", stringify!($SelfT), "::MIN + 1);")]
2043 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_div(-1), ", stringify!($SelfT), "::MAX);")]
2044 ///
2045 /// ```
2046 #[stable(feature = "saturating_div", since = "1.58.0")]
2047 #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
2048 #[must_use = "this returns the result of the operation, \
2049 without modifying the original"]
2050 #[inline]
2051 pub const fn saturating_div(self, rhs: Self) -> Self {
2052 match self.overflowing_div(rhs) {
2053 (result, false) => result,
2054 (_result, true) => Self::MAX, // MIN / -1 is the only possible saturating overflow
2055 }
2056 }
2057
2058 /// Saturating integer exponentiation. Computes `self.pow(exp)`,
2059 /// saturating at the numeric bounds instead of overflowing.
2060 ///
2061 /// # Examples
2062 ///
2063 /// ```
2064 #[doc = concat!("assert_eq!((-4", stringify!($SelfT), ").saturating_pow(3), -64);")]
2065 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".saturating_pow(0), 1);")]
2066 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
2067 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(3), ", stringify!($SelfT), "::MIN);")]
2068 /// ```
2069 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2070 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2071 #[must_use = "this returns the result of the operation, \
2072 without modifying the original"]
2073 #[inline]
2074 pub const fn saturating_pow(self, exp: u32) -> Self {
2075 match self.checked_pow(exp) {
2076 Some(x) => x,
2077 None if self < 0 && exp % 2 == 1 => Self::MIN,
2078 None => Self::MAX,
2079 }
2080 }
2081
2082 /// Wrapping (modular) addition. Computes `self + rhs`, wrapping around at the
2083 /// boundary of the type.
2084 ///
2085 /// # Examples
2086 ///
2087 /// ```
2088 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add(27), 127);")]
2089 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add(2), ", stringify!($SelfT), "::MIN + 1);")]
2090 /// ```
2091 #[stable(feature = "rust1", since = "1.0.0")]
2092 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2093 #[must_use = "this returns the result of the operation, \
2094 without modifying the original"]
2095 #[inline(always)]
2096 pub const fn wrapping_add(self, rhs: Self) -> Self {
2097 intrinsics::wrapping_add(self, rhs)
2098 }
2099
2100 /// Wrapping (modular) addition with an unsigned integer. Computes
2101 /// `self + rhs`, wrapping around at the boundary of the type.
2102 ///
2103 /// # Examples
2104 ///
2105 /// ```
2106 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add_unsigned(27), 127);")]
2107 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add_unsigned(2), ", stringify!($SelfT), "::MIN + 1);")]
2108 /// ```
2109 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2110 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2111 #[must_use = "this returns the result of the operation, \
2112 without modifying the original"]
2113 #[inline(always)]
2114 pub const fn wrapping_add_unsigned(self, rhs: $UnsignedT) -> Self {
2115 self.wrapping_add(rhs as Self)
2116 }
2117
2118 /// Wrapping (modular) subtraction. Computes `self - rhs`, wrapping around at the
2119 /// boundary of the type.
2120 ///
2121 /// # Examples
2122 ///
2123 /// ```
2124 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub(127), -127);")]
2125 #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub(", stringify!($SelfT), "::MAX), ", stringify!($SelfT), "::MAX);")]
2126 /// ```
2127 #[stable(feature = "rust1", since = "1.0.0")]
2128 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2129 #[must_use = "this returns the result of the operation, \
2130 without modifying the original"]
2131 #[inline(always)]
2132 pub const fn wrapping_sub(self, rhs: Self) -> Self {
2133 intrinsics::wrapping_sub(self, rhs)
2134 }
2135
2136 /// Wrapping (modular) subtraction with an unsigned integer. Computes
2137 /// `self - rhs`, wrapping around at the boundary of the type.
2138 ///
2139 /// # Examples
2140 ///
2141 /// ```
2142 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub_unsigned(127), -127);")]
2143 #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub_unsigned(", stringify!($UnsignedT), "::MAX), -1);")]
2144 /// ```
2145 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2146 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2147 #[must_use = "this returns the result of the operation, \
2148 without modifying the original"]
2149 #[inline(always)]
2150 pub const fn wrapping_sub_unsigned(self, rhs: $UnsignedT) -> Self {
2151 self.wrapping_sub(rhs as Self)
2152 }
2153
2154 /// Wrapping (modular) multiplication. Computes `self * rhs`, wrapping around at
2155 /// the boundary of the type.
2156 ///
2157 /// # Examples
2158 ///
2159 /// ```
2160 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".wrapping_mul(12), 120);")]
2161 /// assert_eq!(11i8.wrapping_mul(12), -124);
2162 /// ```
2163 #[stable(feature = "rust1", since = "1.0.0")]
2164 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2165 #[must_use = "this returns the result of the operation, \
2166 without modifying the original"]
2167 #[inline(always)]
2168 pub const fn wrapping_mul(self, rhs: Self) -> Self {
2169 intrinsics::wrapping_mul(self, rhs)
2170 }
2171
2172 /// Wrapping (modular) division. Computes `self / rhs`, wrapping around at the
2173 /// boundary of the type.
2174 ///
2175 /// The only case where such wrapping can occur is when one divides `MIN / -1` on a signed type (where
2176 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
2177 /// that is too large to represent in the type. In such a case, this function returns `MIN` itself.
2178 ///
2179 /// # Panics
2180 ///
2181 /// This function will panic if `rhs` is zero.
2182 ///
2183 /// # Examples
2184 ///
2185 /// ```
2186 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
2187 /// assert_eq!((-128i8).wrapping_div(-1), -128);
2188 /// ```
2189 #[stable(feature = "num_wrapping", since = "1.2.0")]
2190 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2191 #[must_use = "this returns the result of the operation, \
2192 without modifying the original"]
2193 #[inline]
2194 pub const fn wrapping_div(self, rhs: Self) -> Self {
2195 self.overflowing_div(rhs).0
2196 }
2197
2198 /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`,
2199 /// wrapping around at the boundary of the type.
2200 ///
2201 /// Wrapping will only occur in `MIN / -1` on a signed type (where `MIN` is the negative minimal value
2202 /// for the type). This is equivalent to `-MIN`, a positive value that is too large to represent in the
2203 /// type. In this case, this method returns `MIN` itself.
2204 ///
2205 /// # Panics
2206 ///
2207 /// This function will panic if `rhs` is zero.
2208 ///
2209 /// # Examples
2210 ///
2211 /// ```
2212 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
2213 /// assert_eq!((-128i8).wrapping_div_euclid(-1), -128);
2214 /// ```
2215 #[stable(feature = "euclidean_division", since = "1.38.0")]
2216 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2217 #[must_use = "this returns the result of the operation, \
2218 without modifying the original"]
2219 #[inline]
2220 pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
2221 self.overflowing_div_euclid(rhs).0
2222 }
2223
2224 /// Wrapping (modular) remainder. Computes `self % rhs`, wrapping around at the
2225 /// boundary of the type.
2226 ///
2227 /// Such wrap-around never actually occurs mathematically; implementation artifacts make `x % y`
2228 /// invalid for `MIN / -1` on a signed type (where `MIN` is the negative minimal value). In such a case,
2229 /// this function returns `0`.
2230 ///
2231 /// # Panics
2232 ///
2233 /// This function will panic if `rhs` is zero.
2234 ///
2235 /// # Examples
2236 ///
2237 /// ```
2238 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
2239 /// assert_eq!((-128i8).wrapping_rem(-1), 0);
2240 /// ```
2241 #[stable(feature = "num_wrapping", since = "1.2.0")]
2242 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2243 #[must_use = "this returns the result of the operation, \
2244 without modifying the original"]
2245 #[inline]
2246 pub const fn wrapping_rem(self, rhs: Self) -> Self {
2247 self.overflowing_rem(rhs).0
2248 }
2249
2250 /// Wrapping Euclidean remainder. Computes `self.rem_euclid(rhs)`, wrapping around
2251 /// at the boundary of the type.
2252 ///
2253 /// Wrapping will only occur in `MIN % -1` on a signed type (where `MIN` is the negative minimal value
2254 /// for the type). In this case, this method returns 0.
2255 ///
2256 /// # Panics
2257 ///
2258 /// This function will panic if `rhs` is zero.
2259 ///
2260 /// # Examples
2261 ///
2262 /// ```
2263 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
2264 /// assert_eq!((-128i8).wrapping_rem_euclid(-1), 0);
2265 /// ```
2266 #[stable(feature = "euclidean_division", since = "1.38.0")]
2267 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2268 #[must_use = "this returns the result of the operation, \
2269 without modifying the original"]
2270 #[inline]
2271 pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
2272 self.overflowing_rem_euclid(rhs).0
2273 }
2274
2275 /// Wrapping (modular) negation. Computes `-self`, wrapping around at the boundary
2276 /// of the type.
2277 ///
2278 /// The only case where such wrapping can occur is when one negates `MIN` on a signed type (where `MIN`
2279 /// is the negative minimal value for the type); this is a positive value that is too large to represent
2280 /// in the type. In such a case, this function returns `MIN` itself.
2281 ///
2282 /// # Examples
2283 ///
2284 /// ```
2285 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_neg(), -100);")]
2286 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").wrapping_neg(), 100);")]
2287 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.wrapping_neg(), ", stringify!($SelfT), "::MIN);")]
2288 /// ```
2289 #[stable(feature = "num_wrapping", since = "1.2.0")]
2290 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2291 #[must_use = "this returns the result of the operation, \
2292 without modifying the original"]
2293 #[inline(always)]
2294 pub const fn wrapping_neg(self) -> Self {
2295 (0 as $SelfT).wrapping_sub(self)
2296 }
2297
2298 /// Panic-free bitwise shift-left; yields `self << mask(rhs)`, where `mask` removes
2299 /// any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type.
2300 ///
2301 /// Beware that, unlike most other `wrapping_*` methods on integers, this
2302 /// does *not* give the same result as doing the shift in infinite precision
2303 /// then truncating as needed. The behaviour matches what shift instructions
2304 /// do on many processors, and is what the `<<` operator does when overflow
2305 /// checks are disabled, but numerically it's weird. Consider, instead,
2306 /// using [`Self::unbounded_shl`] which has nicer behaviour.
2307 ///
2308 /// Note that this is *not* the same as a rotate-left; the RHS of a wrapping shift-left is restricted to
2309 /// the range of the type, rather than the bits shifted out of the LHS being returned to the other end.
2310 /// The primitive integer types all implement a [`rotate_left`](Self::rotate_left) function,
2311 /// which may be what you want instead.
2312 ///
2313 /// # Examples
2314 ///
2315 /// ```
2316 #[doc = concat!("assert_eq!((-1_", stringify!($SelfT), ").wrapping_shl(7), -128);")]
2317 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(", stringify!($BITS), "), 42);")]
2318 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(1).wrapping_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
2319 #[doc = concat!("assert_eq!((-1_", stringify!($SelfT), ").wrapping_shl(128), -1);")]
2320 #[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".wrapping_shl(1025), 10);")]
2321 /// ```
2322 #[stable(feature = "num_wrapping", since = "1.2.0")]
2323 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2324 #[must_use = "this returns the result of the operation, \
2325 without modifying the original"]
2326 #[inline(always)]
2327 pub const fn wrapping_shl(self, rhs: u32) -> Self {
2328 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2329 // out of bounds
2330 unsafe {
2331 self.unchecked_shl(rhs & (Self::BITS - 1))
2332 }
2333 }
2334
2335 /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`, where `mask`
2336 /// removes any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type.
2337 ///
2338 /// Beware that, unlike most other `wrapping_*` methods on integers, this
2339 /// does *not* give the same result as doing the shift in infinite precision
2340 /// then truncating as needed. The behaviour matches what shift instructions
2341 /// do on many processors, and is what the `>>` operator does when overflow
2342 /// checks are disabled, but numerically it's weird. Consider, instead,
2343 /// using [`Self::unbounded_shr`] which has nicer behaviour.
2344 ///
2345 /// Note that this is *not* the same as a rotate-right; the RHS of a wrapping shift-right is restricted
2346 /// to the range of the type, rather than the bits shifted out of the LHS being returned to the other
2347 /// end. The primitive integer types all implement a [`rotate_right`](Self::rotate_right) function,
2348 /// which may be what you want instead.
2349 ///
2350 /// # Examples
2351 ///
2352 /// ```
2353 #[doc = concat!("assert_eq!((-128_", stringify!($SelfT), ").wrapping_shr(7), -1);")]
2354 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(", stringify!($BITS), "), 42);")]
2355 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(1).wrapping_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
2356 /// assert_eq!((-128_i16).wrapping_shr(64), -128);
2357 #[doc = concat!("assert_eq!(10_", stringify!($SelfT), ".wrapping_shr(1025), 5);")]
2358 /// ```
2359 #[stable(feature = "num_wrapping", since = "1.2.0")]
2360 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2361 #[must_use = "this returns the result of the operation, \
2362 without modifying the original"]
2363 #[inline(always)]
2364 pub const fn wrapping_shr(self, rhs: u32) -> Self {
2365 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2366 // out of bounds
2367 unsafe {
2368 self.unchecked_shr(rhs & (Self::BITS - 1))
2369 }
2370 }
2371
2372 /// Wrapping (modular) absolute value. Computes `self.abs()`, wrapping around at
2373 /// the boundary of the type.
2374 ///
2375 /// The only case where such wrapping can occur is when one takes the absolute value of the negative
2376 /// minimal value for the type; this is a positive value that is too large to represent in the type. In
2377 /// such a case, this function returns `MIN` itself.
2378 ///
2379 /// # Examples
2380 ///
2381 /// ```
2382 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_abs(), 100);")]
2383 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").wrapping_abs(), 100);")]
2384 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.wrapping_abs(), ", stringify!($SelfT), "::MIN);")]
2385 /// assert_eq!((-128i8).wrapping_abs() as u8, 128);
2386 /// ```
2387 #[stable(feature = "no_panic_abs", since = "1.13.0")]
2388 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2389 #[must_use = "this returns the result of the operation, \
2390 without modifying the original"]
2391 #[allow(unused_attributes)]
2392 #[inline]
2393 pub const fn wrapping_abs(self) -> Self {
2394 if self.is_negative() {
2395 self.wrapping_neg()
2396 } else {
2397 self
2398 }
2399 }
2400
2401 /// Computes the absolute value of `self` without any wrapping
2402 /// or panicking.
2403 ///
2404 ///
2405 /// # Examples
2406 ///
2407 /// ```
2408 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".unsigned_abs(), 100", stringify!($UnsignedT), ");")]
2409 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").unsigned_abs(), 100", stringify!($UnsignedT), ");")]
2410 /// assert_eq!((-128i8).unsigned_abs(), 128u8);
2411 /// ```
2412 #[stable(feature = "unsigned_abs", since = "1.51.0")]
2413 #[rustc_const_stable(feature = "unsigned_abs", since = "1.51.0")]
2414 #[must_use = "this returns the result of the operation, \
2415 without modifying the original"]
2416 #[inline]
2417 pub const fn unsigned_abs(self) -> $UnsignedT {
2418 self.wrapping_abs() as $UnsignedT
2419 }
2420
2421 /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
2422 /// wrapping around at the boundary of the type.
2423 ///
2424 /// # Examples
2425 ///
2426 /// ```
2427 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(4), 81);")]
2428 /// assert_eq!(3i8.wrapping_pow(5), -13);
2429 /// assert_eq!(3i8.wrapping_pow(6), -39);
2430 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_pow(0), 1);")]
2431 /// ```
2432 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2433 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2434 #[must_use = "this returns the result of the operation, \
2435 without modifying the original"]
2436 #[inline]
2437 pub const fn wrapping_pow(self, mut exp: u32) -> Self {
2438 if exp == 0 {
2439 return 1;
2440 }
2441 let mut base = self;
2442 let mut acc: Self = 1;
2443
2444 if intrinsics::is_val_statically_known(exp) {
2445 while exp > 1 {
2446 if (exp & 1) == 1 {
2447 acc = acc.wrapping_mul(base);
2448 }
2449 exp /= 2;
2450 base = base.wrapping_mul(base);
2451 }
2452
2453 // since exp!=0, finally the exp must be 1.
2454 // Deal with the final bit of the exponent separately, since
2455 // squaring the base afterwards is not necessary.
2456 acc.wrapping_mul(base)
2457 } else {
2458 // This is faster than the above when the exponent is not known
2459 // at compile time. We can't use the same code for the constant
2460 // exponent case because LLVM is currently unable to unroll
2461 // this loop.
2462 loop {
2463 if (exp & 1) == 1 {
2464 acc = acc.wrapping_mul(base);
2465 // since exp!=0, finally the exp must be 1.
2466 if exp == 1 {
2467 return acc;
2468 }
2469 }
2470 exp /= 2;
2471 base = base.wrapping_mul(base);
2472 }
2473 }
2474 }
2475
2476 /// Calculates `self` + `rhs`.
2477 ///
2478 /// Returns a tuple of the addition along with a boolean indicating
2479 /// whether an arithmetic overflow would occur. If an overflow would have
2480 /// occurred then the wrapped value is returned (negative if overflowed
2481 /// above [`MAX`](Self::MAX), non-negative if below [`MIN`](Self::MIN)).
2482 ///
2483 /// # Examples
2484 ///
2485 /// ```
2486 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
2487 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (", stringify!($SelfT), "::MIN, true));")]
2488 /// ```
2489 #[stable(feature = "wrapping", since = "1.7.0")]
2490 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2491 #[must_use = "this returns the result of the operation, \
2492 without modifying the original"]
2493 #[inline(always)]
2494 pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
2495 let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
2496 (a as Self, b)
2497 }
2498
2499 /// Calculates `self` + `rhs` + `carry` and checks for overflow.
2500 ///
2501 /// Performs "ternary addition" of two integer operands and a carry-in
2502 /// bit, and returns a tuple of the sum along with a boolean indicating
2503 /// whether an arithmetic overflow would occur. On overflow, the wrapped
2504 /// value is returned.
2505 ///
2506 /// This allows chaining together multiple additions to create a wider
2507 /// addition, and can be useful for bignum addition. This method should
2508 /// only be used for the most significant word; for the less significant
2509 /// words the unsigned method
2510 #[doc = concat!("[`", stringify!($UnsignedT), "::carrying_add`]")]
2511 /// should be used.
2512 ///
2513 /// The output boolean returned by this method is *not* a carry flag,
2514 /// and should *not* be added to a more significant word.
2515 ///
2516 /// If overflow occurred, the wrapped value is returned (negative if overflowed
2517 /// above [`MAX`](Self::MAX), non-negative if below [`MIN`](Self::MIN)).
2518 ///
2519 /// If the input carry is false, this method is equivalent to
2520 /// [`overflowing_add`](Self::overflowing_add).
2521 ///
2522 /// # Examples
2523 ///
2524 /// ```
2525 /// #![feature(signed_bigint_helpers)]
2526 /// // Only the most significant word is signed.
2527 /// //
2528 #[doc = concat!("// 10 MAX (a = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2529 #[doc = concat!("// + -5 9 (b = -5 × 2^", stringify!($BITS), " + 9)")]
2530 /// // ---------
2531 #[doc = concat!("// 6 8 (sum = 6 × 2^", stringify!($BITS), " + 8)")]
2532 ///
2533 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (10, ", stringify!($UnsignedT), "::MAX);")]
2534 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (-5, 9);")]
2535 /// let carry0 = false;
2536 ///
2537 #[doc = concat!("// ", stringify!($UnsignedT), "::carrying_add for the less significant words")]
2538 /// let (sum0, carry1) = a0.carrying_add(b0, carry0);
2539 /// assert_eq!(carry1, true);
2540 ///
2541 #[doc = concat!("// ", stringify!($SelfT), "::carrying_add for the most significant word")]
2542 /// let (sum1, overflow) = a1.carrying_add(b1, carry1);
2543 /// assert_eq!(overflow, false);
2544 ///
2545 /// assert_eq!((sum1, sum0), (6, 8));
2546 /// ```
2547 #[unstable(feature = "signed_bigint_helpers", issue = "151989")]
2548 #[must_use = "this returns the result of the operation, \
2549 without modifying the original"]
2550 #[inline]
2551 pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
2552 // note: longer-term this should be done via an intrinsic.
2553 // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
2554 let (a, b) = self.overflowing_add(rhs);
2555 let (c, d) = a.overflowing_add(carry as $SelfT);
2556 (c, b != d)
2557 }
2558
2559 /// Calculates `self` + `rhs` with an unsigned `rhs`.
2560 ///
2561 /// Returns a tuple of the addition along with a boolean indicating
2562 /// whether an arithmetic overflow would occur. If an overflow would
2563 /// have occurred then the wrapped value is returned.
2564 ///
2565 /// # Examples
2566 ///
2567 /// ```
2568 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_unsigned(2), (3, false));")]
2569 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_add_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MAX, false));")]
2570 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_unsigned(3), (", stringify!($SelfT), "::MIN, true));")]
2571 /// ```
2572 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2573 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2574 #[must_use = "this returns the result of the operation, \
2575 without modifying the original"]
2576 #[inline]
2577 pub const fn overflowing_add_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
2578 let rhs = rhs as Self;
2579 let (res, overflowed) = self.overflowing_add(rhs);
2580 (res, overflowed ^ (rhs < 0))
2581 }
2582
2583 /// Calculates `self` - `rhs`.
2584 ///
2585 /// Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow
2586 /// would occur. If an overflow would have occurred then the wrapped value is returned
2587 /// (negative if overflowed above [`MAX`](Self::MAX), non-negative if below [`MIN`](Self::MIN)).
2588 ///
2589 /// # Examples
2590 ///
2591 /// ```
2592 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
2593 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
2594 /// ```
2595 #[stable(feature = "wrapping", since = "1.7.0")]
2596 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2597 #[must_use = "this returns the result of the operation, \
2598 without modifying the original"]
2599 #[inline(always)]
2600 pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
2601 let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
2602 (a as Self, b)
2603 }
2604
2605 /// Calculates `self` − `rhs` − `borrow` and checks for
2606 /// overflow.
2607 ///
2608 /// Performs "ternary subtraction" by subtracting both an integer
2609 /// operand and a borrow-in bit from `self`, and returns a tuple of the
2610 /// difference along with a boolean indicating whether an arithmetic
2611 /// overflow would occur. On overflow, the wrapped value is returned.
2612 ///
2613 /// This allows chaining together multiple subtractions to create a
2614 /// wider subtraction, and can be useful for bignum subtraction. This
2615 /// method should only be used for the most significant word; for the
2616 /// less significant words the unsigned method
2617 #[doc = concat!("[`", stringify!($UnsignedT), "::borrowing_sub`]")]
2618 /// should be used.
2619 ///
2620 /// The output boolean returned by this method is *not* a borrow flag,
2621 /// and should *not* be subtracted from a more significant word.
2622 ///
2623 /// If overflow occurred, the wrapped value is returned (negative if overflowed
2624 /// above [`MAX`](Self::MAX), non-negative if below [`MIN`](Self::MIN)).
2625 ///
2626 /// If the input borrow is false, this method is equivalent to
2627 /// [`overflowing_sub`](Self::overflowing_sub).
2628 ///
2629 /// # Examples
2630 ///
2631 /// ```
2632 /// #![feature(signed_bigint_helpers)]
2633 /// // Only the most significant word is signed.
2634 /// //
2635 #[doc = concat!("// 6 8 (a = 6 × 2^", stringify!($BITS), " + 8)")]
2636 #[doc = concat!("// - -5 9 (b = -5 × 2^", stringify!($BITS), " + 9)")]
2637 /// // ---------
2638 #[doc = concat!("// 10 MAX (diff = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2639 ///
2640 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (6, 8);")]
2641 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (-5, 9);")]
2642 /// let borrow0 = false;
2643 ///
2644 #[doc = concat!("// ", stringify!($UnsignedT), "::borrowing_sub for the less significant words")]
2645 /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
2646 /// assert_eq!(borrow1, true);
2647 ///
2648 #[doc = concat!("// ", stringify!($SelfT), "::borrowing_sub for the most significant word")]
2649 /// let (diff1, overflow) = a1.borrowing_sub(b1, borrow1);
2650 /// assert_eq!(overflow, false);
2651 ///
2652 #[doc = concat!("assert_eq!((diff1, diff0), (10, ", stringify!($UnsignedT), "::MAX));")]
2653 /// ```
2654 #[unstable(feature = "signed_bigint_helpers", issue = "151989")]
2655 #[must_use = "this returns the result of the operation, \
2656 without modifying the original"]
2657 #[inline]
2658 pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
2659 // note: longer-term this should be done via an intrinsic.
2660 // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
2661 let (a, b) = self.overflowing_sub(rhs);
2662 let (c, d) = a.overflowing_sub(borrow as $SelfT);
2663 (c, b != d)
2664 }
2665
2666 /// Calculates `self` - `rhs` with an unsigned `rhs`.
2667 ///
2668 /// Returns a tuple of the subtraction along with a boolean indicating
2669 /// whether an arithmetic overflow would occur. If an overflow would
2670 /// have occurred then the wrapped value is returned.
2671 ///
2672 /// # Examples
2673 ///
2674 /// ```
2675 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_unsigned(2), (-1, false));")]
2676 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).overflowing_sub_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MIN, false));")]
2677 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).overflowing_sub_unsigned(3), (", stringify!($SelfT), "::MAX, true));")]
2678 /// ```
2679 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2680 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2681 #[must_use = "this returns the result of the operation, \
2682 without modifying the original"]
2683 #[inline]
2684 pub const fn overflowing_sub_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
2685 let rhs = rhs as Self;
2686 let (res, overflowed) = self.overflowing_sub(rhs);
2687 (res, overflowed ^ (rhs < 0))
2688 }
2689
2690 /// Calculates the multiplication of `self` and `rhs`.
2691 ///
2692 /// Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow
2693 /// would occur. If an overflow would have occurred then the wrapped value is returned.
2694 ///
2695 /// # Examples
2696 ///
2697 /// ```
2698 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_mul(2), (10, false));")]
2699 /// assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));
2700 /// ```
2701 #[stable(feature = "wrapping", since = "1.7.0")]
2702 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2703 #[must_use = "this returns the result of the operation, \
2704 without modifying the original"]
2705 #[inline(always)]
2706 pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
2707 let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
2708 (a as Self, b)
2709 }
2710
2711 /// Calculates the complete product `self * rhs` without the possibility to overflow.
2712 ///
2713 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2714 /// of the result as two separate values, in that order.
2715 ///
2716 /// If you also need to add a carry to the wide result, then you want
2717 /// [`Self::carrying_mul`] instead.
2718 ///
2719 /// # Examples
2720 ///
2721 /// Please note that this example is shared among integer types, which is why `i32` is used.
2722 ///
2723 /// ```
2724 /// #![feature(widening_mul)]
2725 /// assert_eq!(5i32.widening_mul(-2), (4294967286, -1));
2726 /// assert_eq!(1_000_000_000i32.widening_mul(-10), (2884901888, -3));
2727 /// ```
2728 #[unstable(feature = "widening_mul", issue = "152016")]
2729 #[rustc_const_unstable(feature = "widening_mul", issue = "152016")]
2730 #[must_use = "this returns the result of the operation, \
2731 without modifying the original"]
2732 #[inline]
2733 pub const fn widening_mul(self, rhs: Self) -> ($UnsignedT, Self) {
2734 Self::carrying_mul_add(self, rhs, 0, 0)
2735 }
2736
2737 /// Calculates the "full multiplication" `self * rhs + carry`
2738 /// without the possibility to overflow.
2739 ///
2740 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2741 /// of the result as two separate values, in that order.
2742 ///
2743 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2744 /// additional amount of overflow. This allows for chaining together multiple
2745 /// multiplications to create "big integers" which represent larger values.
2746 ///
2747 /// If you don't need the `carry`, then you can use [`Self::widening_mul`] instead.
2748 ///
2749 /// # Examples
2750 ///
2751 /// Please note that this example is shared among integer types, which is why `i32` is used.
2752 ///
2753 /// ```
2754 /// #![feature(signed_bigint_helpers)]
2755 /// assert_eq!(5i32.carrying_mul(-2, 0), (4294967286, -1));
2756 /// assert_eq!(5i32.carrying_mul(-2, 10), (0, 0));
2757 /// assert_eq!(1_000_000_000i32.carrying_mul(-10, 0), (2884901888, -3));
2758 /// assert_eq!(1_000_000_000i32.carrying_mul(-10, 10), (2884901898, -3));
2759 #[doc = concat!("assert_eq!(",
2760 stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2761 "(", stringify!($SelfT), "::MAX.unsigned_abs() + 1, ", stringify!($SelfT), "::MAX / 2));"
2762 )]
2763 /// ```
2764 #[unstable(feature = "signed_bigint_helpers", issue = "151989")]
2765 #[rustc_const_unstable(feature = "signed_bigint_helpers", issue = "151989")]
2766 #[must_use = "this returns the result of the operation, \
2767 without modifying the original"]
2768 #[inline]
2769 pub const fn carrying_mul(self, rhs: Self, carry: Self) -> ($UnsignedT, Self) {
2770 Self::carrying_mul_add(self, rhs, carry, 0)
2771 }
2772
2773 /// Calculates the "full multiplication" `self * rhs + carry + add`
2774 /// without the possibility to overflow.
2775 ///
2776 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2777 /// of the result as two separate values, in that order.
2778 ///
2779 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2780 /// additional amount of overflow. This allows for chaining together multiple
2781 /// multiplications to create "big integers" which represent larger values.
2782 ///
2783 /// If you don't need either `carry`, then you can use [`Self::widening_mul`] instead,
2784 /// and if you only need one `carry`, then you can use [`Self::carrying_mul`] instead.
2785 ///
2786 /// # Examples
2787 ///
2788 /// Please note that this example is shared among integer types, which is why `i32` is used.
2789 ///
2790 /// ```
2791 /// #![feature(signed_bigint_helpers)]
2792 /// assert_eq!(5i32.carrying_mul_add(-2, 0, 0), (4294967286, -1));
2793 /// assert_eq!(5i32.carrying_mul_add(-2, 10, 10), (10, 0));
2794 /// assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 0, 0), (2884901888, -3));
2795 /// assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 10, 10), (2884901908, -3));
2796 #[doc = concat!("assert_eq!(",
2797 stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2798 "(", stringify!($UnsignedT), "::MAX, ", stringify!($SelfT), "::MAX / 2));"
2799 )]
2800 /// ```
2801 #[unstable(feature = "signed_bigint_helpers", issue = "151989")]
2802 #[rustc_const_unstable(feature = "signed_bigint_helpers", issue = "151989")]
2803 #[must_use = "this returns the result of the operation, \
2804 without modifying the original"]
2805 #[inline]
2806 pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> ($UnsignedT, Self) {
2807 intrinsics::carrying_mul_add(self, rhs, carry, add)
2808 }
2809
2810 /// Calculates the divisor when `self` is divided by `rhs`.
2811 ///
2812 /// Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
2813 /// occur. If an overflow would occur then self is returned.
2814 ///
2815 /// # Panics
2816 ///
2817 /// This function will panic if `rhs` is zero.
2818 ///
2819 /// # Examples
2820 ///
2821 /// ```
2822 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
2823 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div(-1), (", stringify!($SelfT), "::MIN, true));")]
2824 /// ```
2825 #[inline]
2826 #[stable(feature = "wrapping", since = "1.7.0")]
2827 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2828 #[must_use = "this returns the result of the operation, \
2829 without modifying the original"]
2830 pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
2831 // Using `&` helps LLVM see that it is the same check made in division.
2832 if intrinsics::unlikely((self == Self::MIN) & (rhs == -1)) {
2833 (self, true)
2834 } else {
2835 (self / rhs, false)
2836 }
2837 }
2838
2839 /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`.
2840 ///
2841 /// Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
2842 /// occur. If an overflow would occur then `self` is returned.
2843 ///
2844 /// # Panics
2845 ///
2846 /// This function will panic if `rhs` is zero.
2847 ///
2848 /// # Examples
2849 ///
2850 /// ```
2851 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
2852 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div_euclid(-1), (", stringify!($SelfT), "::MIN, true));")]
2853 /// ```
2854 #[inline]
2855 #[stable(feature = "euclidean_division", since = "1.38.0")]
2856 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2857 #[must_use = "this returns the result of the operation, \
2858 without modifying the original"]
2859 pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
2860 // Using `&` helps LLVM see that it is the same check made in division.
2861 if intrinsics::unlikely((self == Self::MIN) & (rhs == -1)) {
2862 (self, true)
2863 } else {
2864 (self.div_euclid(rhs), false)
2865 }
2866 }
2867
2868 /// Calculates the remainder when `self` is divided by `rhs`.
2869 ///
2870 /// Returns a tuple of the remainder after dividing along with a boolean indicating whether an
2871 /// arithmetic overflow would occur. If an overflow would occur then 0 is returned.
2872 ///
2873 /// # Panics
2874 ///
2875 /// This function will panic if `rhs` is zero.
2876 ///
2877 /// # Examples
2878 ///
2879 /// ```
2880 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
2881 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem(-1), (0, true));")]
2882 /// ```
2883 #[inline]
2884 #[stable(feature = "wrapping", since = "1.7.0")]
2885 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2886 #[must_use = "this returns the result of the operation, \
2887 without modifying the original"]
2888 pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
2889 if intrinsics::unlikely(rhs == -1) {
2890 (0, self == Self::MIN)
2891 } else {
2892 (self % rhs, false)
2893 }
2894 }
2895
2896
2897 /// Overflowing Euclidean remainder. Calculates `self.rem_euclid(rhs)`.
2898 ///
2899 /// Returns a tuple of the remainder after dividing along with a boolean indicating whether an
2900 /// arithmetic overflow would occur. If an overflow would occur then 0 is returned.
2901 ///
2902 /// # Panics
2903 ///
2904 /// This function will panic if `rhs` is zero.
2905 ///
2906 /// # Examples
2907 ///
2908 /// ```
2909 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
2910 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem_euclid(-1), (0, true));")]
2911 /// ```
2912 #[stable(feature = "euclidean_division", since = "1.38.0")]
2913 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2914 #[must_use = "this returns the result of the operation, \
2915 without modifying the original"]
2916 #[inline]
2917 #[track_caller]
2918 pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
2919 if intrinsics::unlikely(rhs == -1) {
2920 (0, self == Self::MIN)
2921 } else {
2922 (self.rem_euclid(rhs), false)
2923 }
2924 }
2925
2926
2927 /// Negates self, overflowing if this is equal to the minimum value.
2928 ///
2929 /// Returns a tuple of the negated version of self along with a boolean indicating whether an overflow
2930 /// happened. If `self` is the minimum value (e.g., `i32::MIN` for values of type `i32`), then the
2931 /// minimum value will be returned again and `true` will be returned for an overflow happening.
2932 ///
2933 /// # Examples
2934 ///
2935 /// ```
2936 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2, false));")]
2937 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_neg(), (", stringify!($SelfT), "::MIN, true));")]
2938 /// ```
2939 #[inline]
2940 #[stable(feature = "wrapping", since = "1.7.0")]
2941 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2942 #[must_use = "this returns the result of the operation, \
2943 without modifying the original"]
2944 #[allow(unused_attributes)]
2945 pub const fn overflowing_neg(self) -> (Self, bool) {
2946 if intrinsics::unlikely(self == Self::MIN) {
2947 (Self::MIN, true)
2948 } else {
2949 (-self, false)
2950 }
2951 }
2952
2953 /// Shifts self left by `rhs` bits.
2954 ///
2955 /// Returns a tuple of the shifted version of self along with a boolean indicating whether the shift
2956 /// value was larger than or equal to the number of bits. If the shift value is too large, then value is
2957 /// masked (N-1) where N is the number of bits, and this value is then used to perform the shift.
2958 ///
2959 /// # Examples
2960 ///
2961 /// ```
2962 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT),".overflowing_shl(4), (0x10, false));")]
2963 /// assert_eq!(0x1i32.overflowing_shl(36), (0x10, true));
2964 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
2965 /// ```
2966 #[stable(feature = "wrapping", since = "1.7.0")]
2967 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2968 #[must_use = "this returns the result of the operation, \
2969 without modifying the original"]
2970 #[inline]
2971 pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
2972 (self.wrapping_shl(rhs), rhs >= Self::BITS)
2973 }
2974
2975 /// Shifts self right by `rhs` bits.
2976 ///
2977 /// Returns a tuple of the shifted version of self along with a boolean indicating whether the shift
2978 /// value was larger than or equal to the number of bits. If the shift value is too large, then value is
2979 /// masked (N-1) where N is the number of bits, and this value is then used to perform the shift.
2980 ///
2981 /// # Examples
2982 ///
2983 /// ```
2984 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
2985 /// assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
2986 /// ```
2987 #[stable(feature = "wrapping", since = "1.7.0")]
2988 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2989 #[must_use = "this returns the result of the operation, \
2990 without modifying the original"]
2991 #[inline]
2992 pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
2993 (self.wrapping_shr(rhs), rhs >= Self::BITS)
2994 }
2995
2996 /// Computes the absolute value of `self`.
2997 ///
2998 /// Returns a tuple of the absolute version of self along with a boolean indicating whether an overflow
2999 /// happened. If self is the minimum value
3000 #[doc = concat!("(e.g., ", stringify!($SelfT), "::MIN for values of type ", stringify!($SelfT), "),")]
3001 /// then the minimum value will be returned again and true will be returned
3002 /// for an overflow happening.
3003 ///
3004 /// # Examples
3005 ///
3006 /// ```
3007 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".overflowing_abs(), (10, false));")]
3008 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").overflowing_abs(), (10, false));")]
3009 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_abs(), (", stringify!($SelfT), "::MIN, true));")]
3010 /// ```
3011 #[stable(feature = "no_panic_abs", since = "1.13.0")]
3012 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3013 #[must_use = "this returns the result of the operation, \
3014 without modifying the original"]
3015 #[inline]
3016 pub const fn overflowing_abs(self) -> (Self, bool) {
3017 (self.wrapping_abs(), self == Self::MIN)
3018 }
3019
3020 /// Raises self to the power of `exp`, using exponentiation by squaring.
3021 ///
3022 /// Returns a tuple of the exponentiation along with a bool indicating
3023 /// whether an overflow happened.
3024 ///
3025 /// # Examples
3026 ///
3027 /// ```
3028 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(4), (81, false));")]
3029 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".overflowing_pow(0), (1, false));")]
3030 /// assert_eq!(3i8.overflowing_pow(5), (-13, true));
3031 /// ```
3032 #[stable(feature = "no_panic_pow", since = "1.34.0")]
3033 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3034 #[must_use = "this returns the result of the operation, \
3035 without modifying the original"]
3036 #[inline]
3037 pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
3038 if exp == 0 {
3039 return (1,false);
3040 }
3041 let mut base = self;
3042 let mut acc: Self = 1;
3043 let mut overflown = false;
3044 // Scratch space for storing results of overflowing_mul.
3045 let mut r;
3046
3047 loop {
3048 if (exp & 1) == 1 {
3049 r = acc.overflowing_mul(base);
3050 // since exp!=0, finally the exp must be 1.
3051 if exp == 1 {
3052 r.1 |= overflown;
3053 return r;
3054 }
3055 acc = r.0;
3056 overflown |= r.1;
3057 }
3058 exp /= 2;
3059 r = base.overflowing_mul(base);
3060 base = r.0;
3061 overflown |= r.1;
3062 }
3063 }
3064
3065 /// Raises self to the power of `exp`, using exponentiation by squaring.
3066 ///
3067 /// # Examples
3068 ///
3069 /// ```
3070 #[doc = concat!("let x: ", stringify!($SelfT), " = 2; // or any other integer type")]
3071 ///
3072 /// assert_eq!(x.pow(5), 32);
3073 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".pow(0), 1);")]
3074 /// ```
3075 #[stable(feature = "rust1", since = "1.0.0")]
3076 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3077 #[must_use = "this returns the result of the operation, \
3078 without modifying the original"]
3079 #[inline]
3080 #[rustc_inherit_overflow_checks]
3081 pub const fn pow(self, mut exp: u32) -> Self {
3082 if exp == 0 {
3083 return 1;
3084 }
3085 let mut base = self;
3086 let mut acc = 1;
3087
3088 if intrinsics::is_val_statically_known(exp) {
3089 while exp > 1 {
3090 if (exp & 1) == 1 {
3091 acc = acc * base;
3092 }
3093 exp /= 2;
3094 base = base * base;
3095 }
3096
3097 // since exp!=0, finally the exp must be 1.
3098 // Deal with the final bit of the exponent separately, since
3099 // squaring the base afterwards is not necessary and may cause a
3100 // needless overflow.
3101 acc * base
3102 } else {
3103 // This is faster than the above when the exponent is not known
3104 // at compile time. We can't use the same code for the constant
3105 // exponent case because LLVM is currently unable to unroll
3106 // this loop.
3107 loop {
3108 if (exp & 1) == 1 {
3109 acc = acc * base;
3110 // since exp!=0, finally the exp must be 1.
3111 if exp == 1 {
3112 return acc;
3113 }
3114 }
3115 exp /= 2;
3116 base = base * base;
3117 }
3118 }
3119 }
3120
3121 /// Returns the square root of the number, rounded down.
3122 ///
3123 /// # Panics
3124 ///
3125 /// This function will panic if `self` is negative.
3126 ///
3127 /// # Examples
3128 ///
3129 /// ```
3130 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
3131 /// ```
3132 #[stable(feature = "isqrt", since = "1.84.0")]
3133 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
3134 #[must_use = "this returns the result of the operation, \
3135 without modifying the original"]
3136 #[inline]
3137 #[track_caller]
3138 pub const fn isqrt(self) -> Self {
3139 match self.checked_isqrt() {
3140 Some(sqrt) => sqrt,
3141 None => imp::int_sqrt::panic_for_negative_argument(),
3142 }
3143 }
3144
3145 /// Calculates the quotient of Euclidean division of `self` by `rhs`.
3146 ///
3147 /// This computes the integer `q` such that `self = q * rhs + r`, with
3148 /// `r = self.rem_euclid(rhs)` and `0 <= r < abs(rhs)`.
3149 ///
3150 /// In other words, the result is `self / rhs` rounded to the integer `q`
3151 /// such that `self >= q * rhs`.
3152 /// If `self > 0`, this is equal to rounding towards zero (the default in Rust);
3153 /// if `self < 0`, this is equal to rounding away from zero (towards +/- infinity).
3154 /// If `rhs > 0`, this is equal to rounding towards -infinity;
3155 /// if `rhs < 0`, this is equal to rounding towards +infinity.
3156 ///
3157 /// # Panics
3158 ///
3159 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3160 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3161 ///
3162 /// # Examples
3163 ///
3164 /// ```
3165 #[doc = concat!("let a: ", stringify!($SelfT), " = 7; // or any other integer type")]
3166 /// let b = 4;
3167 ///
3168 /// assert_eq!(a.div_euclid(b), 1); // 7 >= 4 * 1
3169 /// assert_eq!(a.div_euclid(-b), -1); // 7 >= -4 * -1
3170 /// assert_eq!((-a).div_euclid(b), -2); // -7 >= 4 * -2
3171 /// assert_eq!((-a).div_euclid(-b), 2); // -7 >= -4 * 2
3172 /// ```
3173 #[stable(feature = "euclidean_division", since = "1.38.0")]
3174 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3175 #[must_use = "this returns the result of the operation, \
3176 without modifying the original"]
3177 #[inline]
3178 #[track_caller]
3179 pub const fn div_euclid(self, rhs: Self) -> Self {
3180 let q = self / rhs;
3181 if self % rhs < 0 {
3182 return if rhs > 0 { q - 1 } else { q + 1 }
3183 }
3184 q
3185 }
3186
3187
3188 /// Calculates the least nonnegative remainder of `self` when
3189 /// divided by `rhs`.
3190 ///
3191 /// This is done as if by the Euclidean division algorithm -- given
3192 /// `r = self.rem_euclid(rhs)`, the result satisfies
3193 /// `self = rhs * self.div_euclid(rhs) + r` and `0 <= r < abs(rhs)`.
3194 ///
3195 /// # Panics
3196 ///
3197 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN` and
3198 /// `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3199 ///
3200 /// # Examples
3201 ///
3202 /// ```
3203 #[doc = concat!("let a: ", stringify!($SelfT), " = 7; // or any other integer type")]
3204 /// let b = 4;
3205 ///
3206 /// assert_eq!(a.rem_euclid(b), 3);
3207 /// assert_eq!((-a).rem_euclid(b), 1);
3208 /// assert_eq!(a.rem_euclid(-b), 3);
3209 /// assert_eq!((-a).rem_euclid(-b), 1);
3210 /// ```
3211 ///
3212 /// This will panic:
3213 /// ```should_panic
3214 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.rem_euclid(-1);")]
3215 /// ```
3216 #[doc(alias = "modulo", alias = "mod")]
3217 #[stable(feature = "euclidean_division", since = "1.38.0")]
3218 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3219 #[must_use = "this returns the result of the operation, \
3220 without modifying the original"]
3221 #[inline]
3222 #[track_caller]
3223 pub const fn rem_euclid(self, rhs: Self) -> Self {
3224 let r = self % rhs;
3225 if r < 0 {
3226 // Semantically equivalent to `if rhs < 0 { r - rhs } else { r + rhs }`.
3227 // If `rhs` is not `Self::MIN`, then `r + abs(rhs)` will not overflow
3228 // and is clearly equivalent, because `r` is negative.
3229 // Otherwise, `rhs` is `Self::MIN`, then we have
3230 // `r.wrapping_add(Self::MIN.wrapping_abs())`, which evaluates
3231 // to `r.wrapping_add(Self::MIN)`, which is equivalent to
3232 // `r - Self::MIN`, which is what we wanted (and will not overflow
3233 // for negative `r`).
3234 r.wrapping_add(rhs.wrapping_abs())
3235 } else {
3236 r
3237 }
3238 }
3239
3240 /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
3241 ///
3242 /// # Panics
3243 ///
3244 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3245 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3246 ///
3247 /// # Examples
3248 ///
3249 /// ```
3250 /// #![feature(int_roundings)]
3251 #[doc = concat!("let a: ", stringify!($SelfT)," = 8;")]
3252 /// let b = 3;
3253 ///
3254 /// assert_eq!(a.div_floor(b), 2);
3255 /// assert_eq!(a.div_floor(-b), -3);
3256 /// assert_eq!((-a).div_floor(b), -3);
3257 /// assert_eq!((-a).div_floor(-b), 2);
3258 /// ```
3259 #[unstable(feature = "int_roundings", issue = "88581")]
3260 #[must_use = "this returns the result of the operation, \
3261 without modifying the original"]
3262 #[inline]
3263 #[track_caller]
3264 pub const fn div_floor(self, rhs: Self) -> Self {
3265 let d = self / rhs;
3266 let r = self % rhs;
3267
3268 // If the remainder is non-zero, we need to subtract one if the
3269 // signs of self and rhs differ, as this means we rounded upwards
3270 // instead of downwards. We do this branchlessly by creating a mask
3271 // which is all-ones iff the signs differ, and 0 otherwise. Then by
3272 // adding this mask (which corresponds to the signed value -1), we
3273 // get our correction.
3274 let correction = (self ^ rhs) >> (Self::BITS - 1);
3275 if r != 0 {
3276 d + correction
3277 } else {
3278 d
3279 }
3280 }
3281
3282 /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
3283 ///
3284 /// # Panics
3285 ///
3286 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3287 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3288 ///
3289 /// # Examples
3290 ///
3291 /// ```
3292 /// #![feature(int_roundings)]
3293 #[doc = concat!("let a: ", stringify!($SelfT)," = 8;")]
3294 /// let b = 3;
3295 ///
3296 /// assert_eq!(a.div_ceil(b), 3);
3297 /// assert_eq!(a.div_ceil(-b), -2);
3298 /// assert_eq!((-a).div_ceil(b), -2);
3299 /// assert_eq!((-a).div_ceil(-b), 3);
3300 /// ```
3301 #[unstable(feature = "int_roundings", issue = "88581")]
3302 #[must_use = "this returns the result of the operation, \
3303 without modifying the original"]
3304 #[inline]
3305 #[track_caller]
3306 pub const fn div_ceil(self, rhs: Self) -> Self {
3307 let d = self / rhs;
3308 let r = self % rhs;
3309
3310 // When remainder is non-zero we have a.div_ceil(b) == 1 + a.div_floor(b),
3311 // so we can re-use the algorithm from div_floor, just adding 1.
3312 let correction = 1 + ((self ^ rhs) >> (Self::BITS - 1));
3313 if r != 0 {
3314 d + correction
3315 } else {
3316 d
3317 }
3318 }
3319
3320 /// If `rhs` is positive, calculates the smallest value greater than or
3321 /// equal to `self` that is a multiple of `rhs`. If `rhs` is negative,
3322 /// calculates the largest value less than or equal to `self` that is a
3323 /// multiple of `rhs`.
3324 ///
3325 /// # Panics
3326 ///
3327 /// This function will panic if `rhs` is zero.
3328 ///
3329 /// ## Overflow behavior
3330 ///
3331 /// On overflow, this function will panic if overflow checks are enabled (default in debug
3332 /// mode) and wrap if overflow checks are disabled (default in release mode).
3333 ///
3334 /// # Examples
3335 ///
3336 /// ```
3337 /// #![feature(int_roundings)]
3338 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
3339 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
3340 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(-8), 16);")]
3341 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(-8), 16);")]
3342 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").next_multiple_of(8), -16);")]
3343 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").next_multiple_of(8), -16);")]
3344 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").next_multiple_of(-8), -16);")]
3345 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").next_multiple_of(-8), -24);")]
3346 /// ```
3347 #[unstable(feature = "int_roundings", issue = "88581")]
3348 #[must_use = "this returns the result of the operation, \
3349 without modifying the original"]
3350 #[inline]
3351 #[rustc_inherit_overflow_checks]
3352 pub const fn next_multiple_of(self, rhs: Self) -> Self {
3353 // This would otherwise fail when calculating `r` when self == T::MIN.
3354 if rhs == -1 {
3355 return self;
3356 }
3357
3358 let r = self % rhs;
3359 let m = if (r > 0 && rhs < 0) || (r < 0 && rhs > 0) {
3360 r + rhs
3361 } else {
3362 r
3363 };
3364
3365 if m == 0 {
3366 self
3367 } else {
3368 self + (rhs - m)
3369 }
3370 }
3371
3372 /// If `rhs` is positive, calculates the smallest value greater than or
3373 /// equal to `self` that is a multiple of `rhs`. If `rhs` is negative,
3374 /// calculates the largest value less than or equal to `self` that is a
3375 /// multiple of `rhs`. Returns `None` if `rhs` is zero or the operation
3376 /// would result in overflow.
3377 ///
3378 /// # Examples
3379 ///
3380 /// ```
3381 /// #![feature(int_roundings)]
3382 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
3383 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
3384 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(-8), Some(16));")]
3385 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(-8), Some(16));")]
3386 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").checked_next_multiple_of(8), Some(-16));")]
3387 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").checked_next_multiple_of(8), Some(-16));")]
3388 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").checked_next_multiple_of(-8), Some(-16));")]
3389 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").checked_next_multiple_of(-8), Some(-24));")]
3390 #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
3391 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
3392 /// ```
3393 #[unstable(feature = "int_roundings", issue = "88581")]
3394 #[must_use = "this returns the result of the operation, \
3395 without modifying the original"]
3396 #[inline]
3397 pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
3398 // This would otherwise fail when calculating `r` when self == T::MIN.
3399 if rhs == -1 {
3400 return Some(self);
3401 }
3402
3403 let r = try_opt!(self.checked_rem(rhs));
3404 let m = if (r > 0 && rhs < 0) || (r < 0 && rhs > 0) {
3405 // r + rhs cannot overflow because they have opposite signs
3406 r + rhs
3407 } else {
3408 r
3409 };
3410
3411 if m == 0 {
3412 Some(self)
3413 } else {
3414 // rhs - m cannot overflow because m has the same sign as rhs
3415 self.checked_add(rhs - m)
3416 }
3417 }
3418
3419 /// Returns the logarithm of the number with respect to an arbitrary base,
3420 /// rounded down.
3421 ///
3422 /// This method might not be optimized owing to implementation details;
3423 /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
3424 /// can produce results more efficiently for base 10.
3425 ///
3426 /// # Panics
3427 ///
3428 /// This function will panic if `self` is less than or equal to zero,
3429 /// or if `base` is less than 2.
3430 ///
3431 /// # Examples
3432 ///
3433 /// ```
3434 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
3435 /// ```
3436 #[stable(feature = "int_log", since = "1.67.0")]
3437 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3438 #[must_use = "this returns the result of the operation, \
3439 without modifying the original"]
3440 #[inline]
3441 #[track_caller]
3442 pub const fn ilog(self, base: Self) -> u32 {
3443 assert!(base >= 2, "base of integer logarithm must be at least 2");
3444 if let Some(log) = self.checked_ilog(base) {
3445 log
3446 } else {
3447 imp::int_log10::panic_for_nonpositive_argument()
3448 }
3449 }
3450
3451 /// Returns the base 2 logarithm of the number, rounded down.
3452 ///
3453 /// # Panics
3454 ///
3455 /// This function will panic if `self` is less than or equal to zero.
3456 ///
3457 /// # Examples
3458 ///
3459 /// ```
3460 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
3461 /// ```
3462 #[stable(feature = "int_log", since = "1.67.0")]
3463 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3464 #[must_use = "this returns the result of the operation, \
3465 without modifying the original"]
3466 #[inline]
3467 #[track_caller]
3468 pub const fn ilog2(self) -> u32 {
3469 if let Some(log) = self.checked_ilog2() {
3470 log
3471 } else {
3472 imp::int_log10::panic_for_nonpositive_argument()
3473 }
3474 }
3475
3476 /// Returns the base 10 logarithm of the number, rounded down.
3477 ///
3478 /// # Panics
3479 ///
3480 /// This function will panic if `self` is less than or equal to zero.
3481 ///
3482 /// # Example
3483 ///
3484 /// ```
3485 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
3486 /// ```
3487 #[stable(feature = "int_log", since = "1.67.0")]
3488 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3489 #[must_use = "this returns the result of the operation, \
3490 without modifying the original"]
3491 #[inline]
3492 #[track_caller]
3493 pub const fn ilog10(self) -> u32 {
3494 if let Some(log) = self.checked_ilog10() {
3495 log
3496 } else {
3497 imp::int_log10::panic_for_nonpositive_argument()
3498 }
3499 }
3500
3501 /// Returns the logarithm of the number with respect to an arbitrary base,
3502 /// rounded down.
3503 ///
3504 /// Returns `None` if the number is negative or zero, or if the base is not at least 2.
3505 ///
3506 /// This method might not be optimized owing to implementation details;
3507 /// `checked_ilog2` can produce results more efficiently for base 2, and
3508 /// `checked_ilog10` can produce results more efficiently for base 10.
3509 ///
3510 /// # Examples
3511 ///
3512 /// ```
3513 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
3514 /// ```
3515 #[stable(feature = "int_log", since = "1.67.0")]
3516 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3517 #[must_use = "this returns the result of the operation, \
3518 without modifying the original"]
3519 #[inline]
3520 pub const fn checked_ilog(self, base: Self) -> Option<u32> {
3521 if self <= 0 || base <= 1 {
3522 None
3523 } else {
3524 // Delegate to the unsigned implementation.
3525 // The condition makes sure that both casts are exact.
3526 (self as $UnsignedT).checked_ilog(base as $UnsignedT)
3527 }
3528 }
3529
3530 /// Returns the base 2 logarithm of the number, rounded down.
3531 ///
3532 /// Returns `None` if the number is negative or zero.
3533 ///
3534 /// # Examples
3535 ///
3536 /// ```
3537 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
3538 /// ```
3539 #[stable(feature = "int_log", since = "1.67.0")]
3540 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3541 #[must_use = "this returns the result of the operation, \
3542 without modifying the original"]
3543 #[inline]
3544 pub const fn checked_ilog2(self) -> Option<u32> {
3545 if self <= 0 {
3546 None
3547 } else {
3548 // SAFETY: We just checked that this number is positive
3549 let log = (Self::BITS - 1) - unsafe { intrinsics::ctlz_nonzero(self) as u32 };
3550 Some(log)
3551 }
3552 }
3553
3554 /// Returns the base 10 logarithm of the number, rounded down.
3555 ///
3556 /// Returns `None` if the number is negative or zero.
3557 ///
3558 /// # Example
3559 ///
3560 /// ```
3561 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
3562 /// ```
3563 #[stable(feature = "int_log", since = "1.67.0")]
3564 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3565 #[must_use = "this returns the result of the operation, \
3566 without modifying the original"]
3567 #[inline]
3568 pub const fn checked_ilog10(self) -> Option<u32> {
3569 imp::int_log10::$ActualT(self as $ActualT)
3570 }
3571
3572 /// Computes the absolute value of `self`.
3573 ///
3574 /// # Overflow behavior
3575 ///
3576 /// The absolute value of
3577 #[doc = concat!("`", stringify!($SelfT), "::MIN`")]
3578 /// cannot be represented as an
3579 #[doc = concat!("`", stringify!($SelfT), "`,")]
3580 /// and attempting to calculate it will cause an overflow. This means
3581 /// that code in debug mode will trigger a panic on this case and
3582 /// optimized code will return
3583 #[doc = concat!("`", stringify!($SelfT), "::MIN`")]
3584 /// without a panic. If you do not want this behavior, consider
3585 /// using [`unsigned_abs`](Self::unsigned_abs) instead.
3586 ///
3587 /// # Examples
3588 ///
3589 /// ```
3590 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".abs(), 10);")]
3591 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").abs(), 10);")]
3592 /// ```
3593 #[stable(feature = "rust1", since = "1.0.0")]
3594 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3595 #[allow(unused_attributes)]
3596 #[must_use = "this returns the result of the operation, \
3597 without modifying the original"]
3598 #[inline]
3599 #[rustc_inherit_overflow_checks]
3600 pub const fn abs(self) -> Self {
3601 // Note that the #[rustc_inherit_overflow_checks] and #[inline]
3602 // above mean that the overflow semantics of the subtraction
3603 // depend on the crate we're being called from.
3604 if self.is_negative() {
3605 -self
3606 } else {
3607 self
3608 }
3609 }
3610
3611 /// Computes the absolute difference between `self` and `other`.
3612 ///
3613 /// This function always returns the correct answer without overflow or
3614 /// panics by returning an unsigned integer.
3615 ///
3616 /// # Examples
3617 ///
3618 /// ```
3619 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($UnsignedT), ");")]
3620 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($UnsignedT), ");")]
3621 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").abs_diff(80), 180", stringify!($UnsignedT), ");")]
3622 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").abs_diff(-120), 20", stringify!($UnsignedT), ");")]
3623 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.abs_diff(", stringify!($SelfT), "::MAX), ", stringify!($UnsignedT), "::MAX);")]
3624 /// ```
3625 #[stable(feature = "int_abs_diff", since = "1.60.0")]
3626 #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
3627 #[must_use = "this returns the result of the operation, \
3628 without modifying the original"]
3629 #[inline]
3630 pub const fn abs_diff(self, other: Self) -> $UnsignedT {
3631 if self < other {
3632 // Converting a non-negative x from signed to unsigned by using
3633 // `x as U` is left unchanged, but a negative x is converted
3634 // to value x + 2^N. Thus if `s` and `o` are binary variables
3635 // respectively indicating whether `self` and `other` are
3636 // negative, we are computing the mathematical value:
3637 //
3638 // (other + o*2^N) - (self + s*2^N) mod 2^N
3639 // other - self + (o-s)*2^N mod 2^N
3640 // other - self mod 2^N
3641 //
3642 // Finally, taking the mod 2^N of the mathematical value of
3643 // `other - self` does not change it as it already is
3644 // in the range [0, 2^N).
3645 (other as $UnsignedT).wrapping_sub(self as $UnsignedT)
3646 } else {
3647 (self as $UnsignedT).wrapping_sub(other as $UnsignedT)
3648 }
3649 }
3650
3651 /// Returns a number representing sign of `self`.
3652 ///
3653 /// - `0` if the number is zero
3654 /// - `1` if the number is positive
3655 /// - `-1` if the number is negative
3656 ///
3657 /// # Examples
3658 ///
3659 /// ```
3660 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".signum(), 1);")]
3661 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".signum(), 0);")]
3662 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").signum(), -1);")]
3663 /// ```
3664 #[stable(feature = "rust1", since = "1.0.0")]
3665 #[rustc_const_stable(feature = "const_int_sign", since = "1.47.0")]
3666 #[must_use = "this returns the result of the operation, \
3667 without modifying the original"]
3668 #[inline(always)]
3669 pub const fn signum(self) -> Self {
3670 // Picking the right way to phrase this is complicated
3671 // (<https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>)
3672 // so delegate it to `Ord` which is already producing -1/0/+1
3673 // exactly like we need and can be the place to deal with the complexity.
3674
3675 crate::intrinsics::three_way_compare(self, 0) as Self
3676 }
3677
3678 /// Returns `true` if `self` is positive and `false` if the number is zero or
3679 /// negative.
3680 ///
3681 /// # Examples
3682 ///
3683 /// ```
3684 #[doc = concat!("assert!(10", stringify!($SelfT), ".is_positive());")]
3685 #[doc = concat!("assert!(!(-10", stringify!($SelfT), ").is_positive());")]
3686 /// ```
3687 #[must_use]
3688 #[stable(feature = "rust1", since = "1.0.0")]
3689 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3690 #[inline(always)]
3691 pub const fn is_positive(self) -> bool { self > 0 }
3692
3693 /// Returns `true` if `self` is negative and `false` if the number is zero or
3694 /// positive.
3695 ///
3696 /// # Examples
3697 ///
3698 /// ```
3699 #[doc = concat!("assert!((-10", stringify!($SelfT), ").is_negative());")]
3700 #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_negative());")]
3701 /// ```
3702 #[must_use]
3703 #[stable(feature = "rust1", since = "1.0.0")]
3704 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3705 #[inline(always)]
3706 pub const fn is_negative(self) -> bool { self < 0 }
3707
3708 /// Returns the memory representation of this integer as a byte array in
3709 /// big-endian (network) byte order.
3710 ///
3711 #[doc = $to_xe_bytes_doc]
3712 ///
3713 /// # Examples
3714 ///
3715 /// ```
3716 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
3717 #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
3718 /// ```
3719 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3720 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3721 #[must_use = "this returns the result of the operation, \
3722 without modifying the original"]
3723 #[inline]
3724 pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] {
3725 self.to_be().to_ne_bytes()
3726 }
3727
3728 /// Returns the memory representation of this integer as a byte array in
3729 /// little-endian byte order.
3730 ///
3731 #[doc = $to_xe_bytes_doc]
3732 ///
3733 /// # Examples
3734 ///
3735 /// ```
3736 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
3737 #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
3738 /// ```
3739 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3740 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3741 #[must_use = "this returns the result of the operation, \
3742 without modifying the original"]
3743 #[inline]
3744 pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] {
3745 self.to_le().to_ne_bytes()
3746 }
3747
3748 /// Returns the memory representation of this integer as a byte array in
3749 /// native byte order.
3750 ///
3751 /// As the target platform's native endianness is used, portable code
3752 /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
3753 /// instead.
3754 ///
3755 #[doc = $to_xe_bytes_doc]
3756 ///
3757 /// [`to_be_bytes`]: Self::to_be_bytes
3758 /// [`to_le_bytes`]: Self::to_le_bytes
3759 ///
3760 /// # Examples
3761 ///
3762 /// ```
3763 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
3764 /// assert_eq!(
3765 /// bytes,
3766 /// if cfg!(target_endian = "big") {
3767 #[doc = concat!(" ", $be_bytes)]
3768 /// } else {
3769 #[doc = concat!(" ", $le_bytes)]
3770 /// }
3771 /// );
3772 /// ```
3773 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3774 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3775 #[allow(unnecessary_transmutes)]
3776 // SAFETY: const sound because integers are plain old datatypes so we can always
3777 // transmute them to arrays of bytes
3778 #[must_use = "this returns the result of the operation, \
3779 without modifying the original"]
3780 #[inline]
3781 pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] {
3782 // SAFETY: integers are plain old datatypes so we can always transmute them to
3783 // arrays of bytes
3784 unsafe { mem::transmute(self) }
3785 }
3786
3787 /// Creates an integer value from its representation as a byte array in
3788 /// big endian.
3789 ///
3790 #[doc = $from_xe_bytes_doc]
3791 ///
3792 /// # Examples
3793 ///
3794 /// ```
3795 #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
3796 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3797 /// ```
3798 ///
3799 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3800 ///
3801 /// ```
3802 #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3803 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3804 /// *input = rest;
3805 #[doc = concat!(" ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
3806 /// }
3807 /// ```
3808 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3809 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3810 #[must_use]
3811 #[inline]
3812 pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3813 Self::from_be(Self::from_ne_bytes(bytes))
3814 }
3815
3816 /// Creates an integer value from its representation as a byte array in
3817 /// little endian.
3818 ///
3819 #[doc = $from_xe_bytes_doc]
3820 ///
3821 /// # Examples
3822 ///
3823 /// ```
3824 #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
3825 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3826 /// ```
3827 ///
3828 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3829 ///
3830 /// ```
3831 #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3832 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3833 /// *input = rest;
3834 #[doc = concat!(" ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
3835 /// }
3836 /// ```
3837 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3838 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3839 #[must_use]
3840 #[inline]
3841 pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3842 Self::from_le(Self::from_ne_bytes(bytes))
3843 }
3844
3845 /// Creates an integer value from its memory representation as a byte
3846 /// array in native endianness.
3847 ///
3848 /// As the target platform's native endianness is used, portable code
3849 /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
3850 /// appropriate instead.
3851 ///
3852 /// [`from_be_bytes`]: Self::from_be_bytes
3853 /// [`from_le_bytes`]: Self::from_le_bytes
3854 ///
3855 #[doc = $from_xe_bytes_doc]
3856 ///
3857 /// # Examples
3858 ///
3859 /// ```
3860 #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
3861 #[doc = concat!(" ", $be_bytes)]
3862 /// } else {
3863 #[doc = concat!(" ", $le_bytes)]
3864 /// });
3865 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3866 /// ```
3867 ///
3868 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3869 ///
3870 /// ```
3871 #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3872 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3873 /// *input = rest;
3874 #[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
3875 /// }
3876 /// ```
3877 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3878 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3879 #[allow(unnecessary_transmutes)]
3880 #[must_use]
3881 // SAFETY: const sound because integers are plain old datatypes so we can always
3882 // transmute to them
3883 #[inline]
3884 pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3885 // SAFETY: integers are plain old datatypes so we can always transmute to them
3886 unsafe { mem::transmute(bytes) }
3887 }
3888
3889 /// New code should prefer to use
3890 #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
3891 ///
3892 /// Returns the smallest value that can be represented by this integer type.
3893 #[stable(feature = "rust1", since = "1.0.0")]
3894 #[inline(always)]
3895 #[rustc_promotable]
3896 #[rustc_const_stable(feature = "const_min_value", since = "1.32.0")]
3897 #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
3898 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
3899 pub const fn min_value() -> Self {
3900 Self::MIN
3901 }
3902
3903 /// New code should prefer to use
3904 #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
3905 ///
3906 /// Returns the largest value that can be represented by this integer type.
3907 #[stable(feature = "rust1", since = "1.0.0")]
3908 #[inline(always)]
3909 #[rustc_promotable]
3910 #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
3911 #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
3912 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
3913 pub const fn max_value() -> Self {
3914 Self::MAX
3915 }
3916
3917 /// Clamps this number to a symmetric range centred around zero.
3918 ///
3919 /// The method clamps the number's magnitude (absolute value) to be at most `limit`.
3920 ///
3921 /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more
3922 /// explicit about the intent.
3923 ///
3924 /// # Examples
3925 ///
3926 /// ```
3927 /// #![feature(clamp_magnitude)]
3928 #[doc = concat!("assert_eq!(120", stringify!($SelfT), ".clamp_magnitude(100), 100);")]
3929 #[doc = concat!("assert_eq!(-120", stringify!($SelfT), ".clamp_magnitude(100), -100);")]
3930 #[doc = concat!("assert_eq!(80", stringify!($SelfT), ".clamp_magnitude(100), 80);")]
3931 #[doc = concat!("assert_eq!(-80", stringify!($SelfT), ".clamp_magnitude(100), -80);")]
3932 /// ```
3933 #[must_use = "this returns the clamped value and does not modify the original"]
3934 #[unstable(feature = "clamp_magnitude", issue = "148519")]
3935 #[inline]
3936 pub fn clamp_magnitude(self, limit: $UnsignedT) -> Self {
3937 if let Ok(limit) = core::convert::TryInto::<$SelfT>::try_into(limit) {
3938 self.clamp(-limit, limit)
3939 } else {
3940 self
3941 }
3942 }
3943
3944 /// Truncate an integer to an integer of the same size or smaller, preserving the least
3945 /// significant bits.
3946 ///
3947 /// # Examples
3948 ///
3949 /// ```
3950 /// #![feature(integer_extend_truncate)]
3951 #[doc = concat!("assert_eq!(120i8, 120", stringify!($SelfT), ".truncate());")]
3952 #[doc = concat!("assert_eq!(-120i8, (-120", stringify!($SelfT), ").truncate());")]
3953 /// assert_eq!(120i8, 376i32.truncate());
3954 /// ```
3955 #[must_use = "this returns the truncated value and does not modify the original"]
3956 #[unstable(feature = "integer_extend_truncate", issue = "154330")]
3957 #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
3958 #[inline]
3959 pub const fn truncate<Target>(self) -> Target
3960 where Self: [const] traits::TruncateTarget<Target>
3961 {
3962 traits::TruncateTarget::internal_truncate(self)
3963 }
3964
3965 /// Truncate an integer to an integer of the same size or smaller, saturating at numeric bounds
3966 /// instead of truncating.
3967 ///
3968 /// # Examples
3969 ///
3970 /// ```
3971 /// #![feature(integer_extend_truncate)]
3972 #[doc = concat!("assert_eq!(120i8, 120", stringify!($SelfT), ".saturating_truncate());")]
3973 #[doc = concat!("assert_eq!(-120i8, (-120", stringify!($SelfT), ").saturating_truncate());")]
3974 /// assert_eq!(127i8, 376i32.saturating_truncate());
3975 /// assert_eq!(-128i8, (-1000i32).saturating_truncate());
3976 /// ```
3977 #[must_use = "this returns the truncated value and does not modify the original"]
3978 #[unstable(feature = "integer_extend_truncate", issue = "154330")]
3979 #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
3980 #[inline]
3981 pub const fn saturating_truncate<Target>(self) -> Target
3982 where Self: [const] traits::TruncateTarget<Target>
3983 {
3984 traits::TruncateTarget::internal_saturating_truncate(self)
3985 }
3986
3987 /// Truncate an integer to an integer of the same size or smaller, returning `None` if the value
3988 /// is outside the bounds of the smaller type.
3989 ///
3990 /// # Examples
3991 ///
3992 /// ```
3993 /// #![feature(integer_extend_truncate)]
3994 #[doc = concat!("assert_eq!(Some(120i8), 120", stringify!($SelfT), ".checked_truncate());")]
3995 #[doc = concat!("assert_eq!(Some(-120i8), (-120", stringify!($SelfT), ").checked_truncate());")]
3996 /// assert_eq!(None, 376i32.checked_truncate::<i8>());
3997 /// assert_eq!(None, (-1000i32).checked_truncate::<i8>());
3998 /// ```
3999 #[must_use = "this returns the truncated value and does not modify the original"]
4000 #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4001 #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4002 #[inline]
4003 pub const fn checked_truncate<Target>(self) -> Option<Target>
4004 where Self: [const] traits::TruncateTarget<Target>
4005 {
4006 traits::TruncateTarget::internal_checked_truncate(self)
4007 }
4008
4009 /// Extend to an integer of the same size or larger, preserving its value.
4010 ///
4011 /// # Examples
4012 ///
4013 /// ```
4014 /// #![feature(integer_extend_truncate)]
4015 #[doc = concat!("assert_eq!(120i128, 120i8.extend());")]
4016 #[doc = concat!("assert_eq!(-120i128, (-120i8).extend());")]
4017 /// ```
4018 #[must_use = "this returns the extended value and does not modify the original"]
4019 #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4020 #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4021 #[inline]
4022 pub const fn extend<Target>(self) -> Target
4023 where Self: [const] traits::ExtendTarget<Target>
4024 {
4025 traits::ExtendTarget::internal_extend(self)
4026 }
4027 }
4028}