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 $UnsignedT
269 }
270
271 /// Saturating conversion of `self` to an unsigned integer of the same size.
272 ///
273 /// Negative values are clamped to `0`.
274 ///
275 /// For other kinds of unsigned integer casts, see
276 /// [`cast_unsigned`](Self::cast_unsigned),
277 /// [`checked_cast_unsigned`](Self::checked_cast_unsigned),
278 /// or [`strict_cast_unsigned`](Self::strict_cast_unsigned).
279 ///
280 /// # Examples
281 ///
282 /// ```
283 /// #![feature(integer_cast_extras)]
284 #[doc = concat!("let n = ", stringify!($SelfT), "::MIN;")]
285 ///
286 #[doc = concat!("assert_eq!(n.saturating_cast_unsigned(), 0", stringify!($UnsignedT), ");")]
287 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".saturating_cast_unsigned(), 64", stringify!($UnsignedT), ");")]
288 /// ```
289 #[rustc_const_unstable(feature = "integer_cast_extras", issue = "154650")]
290 #[unstable(feature = "integer_cast_extras", issue = "154650")]
291 #[must_use = "this returns the result of the operation, \
292 without modifying the original"]
293 #[inline(always)]
294 pub const fn saturating_cast_unsigned(self) -> $UnsignedT {
295 if self >= 0 {
296 self.cast_unsigned()
297 } else {
298 0
299 }
300 }
301
302 /// Checked conversion of `self` to an unsigned integer of the same size,
303 /// returning `None` if `self` is negative.
304 ///
305 /// For other kinds of unsigned integer casts, see
306 /// [`cast_unsigned`](Self::cast_unsigned),
307 /// [`saturating_cast_unsigned`](Self::saturating_cast_unsigned),
308 /// or [`strict_cast_unsigned`](Self::strict_cast_unsigned).
309 ///
310 /// # Examples
311 ///
312 /// ```
313 /// #![feature(integer_cast_extras)]
314 #[doc = concat!("let n = ", stringify!($SelfT), "::MIN;")]
315 ///
316 #[doc = concat!("assert_eq!(n.checked_cast_unsigned(), None);")]
317 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".checked_cast_unsigned(), Some(64", stringify!($UnsignedT), "));")]
318 /// ```
319 #[rustc_const_unstable(feature = "integer_cast_extras", issue = "154650")]
320 #[unstable(feature = "integer_cast_extras", issue = "154650")]
321 #[must_use = "this returns the result of the operation, \
322 without modifying the original"]
323 #[inline(always)]
324 pub const fn checked_cast_unsigned(self) -> Option<$UnsignedT> {
325 if self >= 0 {
326 Some(self.cast_unsigned())
327 } else {
328 None
329 }
330 }
331
332 /// Strict conversion of `self` to an unsigned integer of the same size,
333 /// which panics if `self` is negative.
334 ///
335 /// For other kinds of unsigned integer casts, see
336 /// [`cast_unsigned`](Self::cast_unsigned),
337 /// [`checked_cast_unsigned`](Self::checked_cast_unsigned),
338 /// or [`saturating_cast_unsigned`](Self::saturating_cast_unsigned).
339 ///
340 /// # Examples
341 ///
342 /// ```should_panic
343 /// #![feature(integer_cast_extras)]
344 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_cast_unsigned();")]
345 /// ```
346 #[rustc_const_unstable(feature = "integer_cast_extras", issue = "154650")]
347 #[unstable(feature = "integer_cast_extras", issue = "154650")]
348 #[must_use = "this returns the result of the operation, \
349 without modifying the original"]
350 #[inline]
351 #[track_caller]
352 pub const fn strict_cast_unsigned(self) -> $UnsignedT {
353 match self.checked_cast_unsigned() {
354 Some(n) => n,
355 None => imp::overflow_panic::cast_integer(),
356 }
357 }
358
359 /// Shifts the bits to the left by a specified amount, `n`,
360 /// wrapping the truncated bits to the end of the resulting integer.
361 ///
362 /// `rotate_left(n)` is equivalent to applying `rotate_left(1)` a total of `n` times. In
363 /// particular, a rotation by the number of bits in `self` returns the input value
364 /// unchanged.
365 ///
366 /// Please note this isn't the same operation as the `<<` shifting operator!
367 ///
368 /// # Examples
369 ///
370 /// ```
371 #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")]
372 #[doc = concat!("let m = ", $rot_result, ";")]
373 ///
374 #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")]
375 #[doc = concat!("assert_eq!(n.rotate_left(1024), n);")]
376 /// ```
377 #[stable(feature = "rust1", since = "1.0.0")]
378 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
379 #[must_use = "this returns the result of the operation, \
380 without modifying the original"]
381 #[inline(always)]
382 pub const fn rotate_left(self, n: u32) -> Self {
383 (self as $UnsignedT).rotate_left(n) as Self
384 }
385
386 /// Shifts the bits to the right by a specified amount, `n`,
387 /// wrapping the truncated bits to the beginning of the resulting
388 /// integer.
389 ///
390 /// `rotate_right(n)` is equivalent to applying `rotate_right(1)` a total of `n` times. In
391 /// particular, a rotation by the number of bits in `self` returns the input value
392 /// unchanged.
393 ///
394 /// Please note this isn't the same operation as the `>>` shifting operator!
395 ///
396 /// # Examples
397 ///
398 /// ```
399 #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")]
400 #[doc = concat!("let m = ", $rot_op, ";")]
401 ///
402 #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")]
403 #[doc = concat!("assert_eq!(n.rotate_right(1024), n);")]
404 /// ```
405 #[stable(feature = "rust1", since = "1.0.0")]
406 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
407 #[must_use = "this returns the result of the operation, \
408 without modifying the original"]
409 #[inline(always)]
410 pub const fn rotate_right(self, n: u32) -> Self {
411 (self as $UnsignedT).rotate_right(n) as Self
412 }
413
414 /// Reverses the byte order of the integer.
415 ///
416 /// # Examples
417 ///
418 /// ```
419 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
420 ///
421 /// let m = n.swap_bytes();
422 ///
423 #[doc = concat!("assert_eq!(m, ", $swapped, ");")]
424 /// ```
425 #[stable(feature = "rust1", since = "1.0.0")]
426 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
427 #[must_use = "this returns the result of the operation, \
428 without modifying the original"]
429 #[inline(always)]
430 pub const fn swap_bytes(self) -> Self {
431 (self as $UnsignedT).swap_bytes() as Self
432 }
433
434 /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit,
435 /// second least-significant bit becomes second most-significant bit, etc.
436 ///
437 /// # Examples
438 ///
439 /// ```
440 #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")]
441 /// let m = n.reverse_bits();
442 ///
443 #[doc = concat!("assert_eq!(m, ", $reversed, ");")]
444 #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")]
445 /// ```
446 #[stable(feature = "reverse_bits", since = "1.37.0")]
447 #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")]
448 #[must_use = "this returns the result of the operation, \
449 without modifying the original"]
450 #[inline(always)]
451 pub const fn reverse_bits(self) -> Self {
452 (self as $UnsignedT).reverse_bits() as Self
453 }
454
455 /// Converts an integer from big endian to the target's endianness.
456 ///
457 /// On big endian this is a no-op. On little endian the bytes are swapped.
458 ///
459 /// See also [from_be_bytes()](Self::from_be_bytes).
460 ///
461 /// # Examples
462 ///
463 /// ```
464 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
465 ///
466 /// if cfg!(target_endian = "big") {
467 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")]
468 /// } else {
469 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")]
470 /// }
471 /// ```
472 #[stable(feature = "rust1", since = "1.0.0")]
473 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
474 #[must_use]
475 #[inline]
476 pub const fn from_be(x: Self) -> Self {
477 #[cfg(target_endian = "big")]
478 {
479 x
480 }
481 #[cfg(not(target_endian = "big"))]
482 {
483 x.swap_bytes()
484 }
485 }
486
487 /// Converts an integer from little endian to the target's endianness.
488 ///
489 /// On little endian this is a no-op. On big endian the bytes are swapped.
490 ///
491 /// See also [from_le_bytes()](Self::from_le_bytes).
492 ///
493 /// # Examples
494 ///
495 /// ```
496 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
497 ///
498 /// if cfg!(target_endian = "little") {
499 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")]
500 /// } else {
501 #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")]
502 /// }
503 /// ```
504 #[stable(feature = "rust1", since = "1.0.0")]
505 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
506 #[must_use]
507 #[inline]
508 pub const fn from_le(x: Self) -> Self {
509 #[cfg(target_endian = "little")]
510 {
511 x
512 }
513 #[cfg(not(target_endian = "little"))]
514 {
515 x.swap_bytes()
516 }
517 }
518
519 /// Swaps bytes of `self` on little endian targets.
520 ///
521 /// On big endian this is a no-op.
522 ///
523 /// The returned value has the same type as `self`, and will be interpreted
524 /// as (a potentially different) value of a native-endian
525 #[doc = concat!("`", stringify!($SelfT), "`.")]
526 ///
527 /// See [`to_be_bytes()`](Self::to_be_bytes) for a type-safe alternative.
528 ///
529 /// # Examples
530 ///
531 /// ```
532 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
533 ///
534 /// if cfg!(target_endian = "big") {
535 /// assert_eq!(n.to_be(), n)
536 /// } else {
537 /// assert_eq!(n.to_be(), n.swap_bytes())
538 /// }
539 /// ```
540 #[stable(feature = "rust1", since = "1.0.0")]
541 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
542 #[must_use = "this returns the result of the operation, \
543 without modifying the original"]
544 #[inline]
545 pub const fn to_be(self) -> Self { // or not to be?
546 #[cfg(target_endian = "big")]
547 {
548 self
549 }
550 #[cfg(not(target_endian = "big"))]
551 {
552 self.swap_bytes()
553 }
554 }
555
556 /// Swaps bytes of `self` on big endian targets.
557 ///
558 /// On little endian this is a no-op.
559 ///
560 /// The returned value has the same type as `self`, and will be interpreted
561 /// as (a potentially different) value of a native-endian
562 #[doc = concat!("`", stringify!($SelfT), "`.")]
563 ///
564 /// See [`to_le_bytes()`](Self::to_le_bytes) for a type-safe alternative.
565 ///
566 /// # Examples
567 ///
568 /// ```
569 #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")]
570 ///
571 /// if cfg!(target_endian = "little") {
572 /// assert_eq!(n.to_le(), n)
573 /// } else {
574 /// assert_eq!(n.to_le(), n.swap_bytes())
575 /// }
576 /// ```
577 #[stable(feature = "rust1", since = "1.0.0")]
578 #[rustc_const_stable(feature = "const_int_conversions", since = "1.32.0")]
579 #[must_use = "this returns the result of the operation, \
580 without modifying the original"]
581 #[inline]
582 pub const fn to_le(self) -> Self {
583 #[cfg(target_endian = "little")]
584 {
585 self
586 }
587 #[cfg(not(target_endian = "little"))]
588 {
589 self.swap_bytes()
590 }
591 }
592
593 /// Checked integer addition. Computes `self + rhs`, returning `None`
594 /// if overflow occurred.
595 ///
596 /// # Examples
597 ///
598 /// ```
599 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), Some(", stringify!($SelfT), "::MAX - 1));")]
600 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")]
601 /// ```
602 #[stable(feature = "rust1", since = "1.0.0")]
603 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
604 #[must_use = "this returns the result of the operation, \
605 without modifying the original"]
606 #[inline]
607 pub const fn checked_add(self, rhs: Self) -> Option<Self> {
608 let (a, b) = self.overflowing_add(rhs);
609 if intrinsics::unlikely(b) { None } else { Some(a) }
610 }
611
612 /// Strict integer addition. Computes `self + rhs`, panicking
613 /// if overflow occurred.
614 ///
615 /// # Panics
616 ///
617 /// ## Overflow behavior
618 ///
619 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
620 ///
621 /// # Examples
622 ///
623 /// ```
624 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")]
625 /// ```
626 ///
627 /// The following panics because of overflow:
628 ///
629 /// ```should_panic
630 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")]
631 /// ```
632 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
633 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
634 #[must_use = "this returns the result of the operation, \
635 without modifying the original"]
636 #[inline]
637 #[track_caller]
638 pub const fn strict_add(self, rhs: Self) -> Self {
639 let (a, b) = self.overflowing_add(rhs);
640 if b { imp::overflow_panic::add() } else { a }
641 }
642
643 /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
644 /// cannot occur.
645 ///
646 /// Calling `x.unchecked_add(y)` is semantically equivalent to calling
647 /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`.
648 ///
649 /// If you're just trying to avoid the panic in debug mode, then **do not**
650 /// use this. Instead, you're looking for [`wrapping_add`].
651 ///
652 /// # Safety
653 ///
654 /// This results in undefined behavior when
655 #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")]
656 /// i.e. when [`checked_add`] would return `None`.
657 ///
658 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
659 #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")]
660 #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")]
661 #[stable(feature = "unchecked_math", since = "1.79.0")]
662 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
663 #[must_use = "this returns the result of the operation, \
664 without modifying the original"]
665 #[inline(always)]
666 #[track_caller]
667 pub const unsafe fn unchecked_add(self, rhs: Self) -> Self {
668 assert_unsafe_precondition!(
669 check_language_ub,
670 concat!(stringify!($SelfT), "::unchecked_add cannot overflow"),
671 (
672 lhs: $SelfT = self,
673 rhs: $SelfT = rhs,
674 ) => !lhs.overflowing_add(rhs).1,
675 );
676
677 // SAFETY: this is guaranteed to be safe by the caller.
678 unsafe {
679 intrinsics::unchecked_add(self, rhs)
680 }
681 }
682
683 /// Checked addition with an unsigned integer. Computes `self + rhs`,
684 /// returning `None` if overflow occurred.
685 ///
686 /// # Examples
687 ///
688 /// ```
689 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_unsigned(2), Some(3));")]
690 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_unsigned(3), None);")]
691 /// ```
692 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
693 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
694 #[must_use = "this returns the result of the operation, \
695 without modifying the original"]
696 #[inline]
697 pub const fn checked_add_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
698 let (a, b) = self.overflowing_add_unsigned(rhs);
699 if intrinsics::unlikely(b) { None } else { Some(a) }
700 }
701
702 /// Strict addition with an unsigned integer. Computes `self + rhs`,
703 /// panicking if overflow occurred.
704 ///
705 /// # Panics
706 ///
707 /// ## Overflow behavior
708 ///
709 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
710 ///
711 /// # Examples
712 ///
713 /// ```
714 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_unsigned(2), 3);")]
715 /// ```
716 ///
717 /// The following panics because of overflow:
718 ///
719 /// ```should_panic
720 #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_unsigned(3);")]
721 /// ```
722 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
723 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
724 #[must_use = "this returns the result of the operation, \
725 without modifying the original"]
726 #[inline]
727 #[track_caller]
728 pub const fn strict_add_unsigned(self, rhs: $UnsignedT) -> Self {
729 let (a, b) = self.overflowing_add_unsigned(rhs);
730 if b { imp::overflow_panic::add() } else { a }
731 }
732
733 /// Checked integer subtraction. Computes `self - rhs`, returning `None` if
734 /// overflow occurred.
735 ///
736 /// # Examples
737 ///
738 /// ```
739 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(1), Some(", stringify!($SelfT), "::MIN + 1));")]
740 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub(3), None);")]
741 /// ```
742 #[stable(feature = "rust1", since = "1.0.0")]
743 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
744 #[must_use = "this returns the result of the operation, \
745 without modifying the original"]
746 #[inline]
747 pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
748 let (a, b) = self.overflowing_sub(rhs);
749 if intrinsics::unlikely(b) { None } else { Some(a) }
750 }
751
752 /// Strict integer subtraction. Computes `self - rhs`, panicking if
753 /// overflow occurred.
754 ///
755 /// # Panics
756 ///
757 /// ## Overflow behavior
758 ///
759 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
760 ///
761 /// # Examples
762 ///
763 /// ```
764 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).strict_sub(1), ", stringify!($SelfT), "::MIN + 1);")]
765 /// ```
766 ///
767 /// The following panics because of overflow:
768 ///
769 /// ```should_panic
770 #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub(3);")]
771 /// ```
772 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
773 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
774 #[must_use = "this returns the result of the operation, \
775 without modifying the original"]
776 #[inline]
777 #[track_caller]
778 pub const fn strict_sub(self, rhs: Self) -> Self {
779 let (a, b) = self.overflowing_sub(rhs);
780 if b { imp::overflow_panic::sub() } else { a }
781 }
782
783 /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
784 /// cannot occur.
785 ///
786 /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling
787 /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`.
788 ///
789 /// If you're just trying to avoid the panic in debug mode, then **do not**
790 /// use this. Instead, you're looking for [`wrapping_sub`].
791 ///
792 /// # Safety
793 ///
794 /// This results in undefined behavior when
795 #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")]
796 /// i.e. when [`checked_sub`] would return `None`.
797 ///
798 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
799 #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")]
800 #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")]
801 #[stable(feature = "unchecked_math", since = "1.79.0")]
802 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
803 #[must_use = "this returns the result of the operation, \
804 without modifying the original"]
805 #[inline(always)]
806 #[track_caller]
807 pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self {
808 assert_unsafe_precondition!(
809 check_language_ub,
810 concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"),
811 (
812 lhs: $SelfT = self,
813 rhs: $SelfT = rhs,
814 ) => !lhs.overflowing_sub(rhs).1,
815 );
816
817 // SAFETY: this is guaranteed to be safe by the caller.
818 unsafe {
819 intrinsics::unchecked_sub(self, rhs)
820 }
821 }
822
823 /// Checked subtraction with an unsigned integer. Computes `self - rhs`,
824 /// returning `None` if overflow occurred.
825 ///
826 /// # Examples
827 ///
828 /// ```
829 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_unsigned(2), Some(-1));")]
830 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).checked_sub_unsigned(3), None);")]
831 /// ```
832 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
833 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
834 #[must_use = "this returns the result of the operation, \
835 without modifying the original"]
836 #[inline]
837 pub const fn checked_sub_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
838 let (a, b) = self.overflowing_sub_unsigned(rhs);
839 if intrinsics::unlikely(b) { None } else { Some(a) }
840 }
841
842 /// Strict subtraction with an unsigned integer. Computes `self - rhs`,
843 /// panicking if overflow occurred.
844 ///
845 /// # Panics
846 ///
847 /// ## Overflow behavior
848 ///
849 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
850 ///
851 /// # Examples
852 ///
853 /// ```
854 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub_unsigned(2), -1);")]
855 /// ```
856 ///
857 /// The following panics because of overflow:
858 ///
859 /// ```should_panic
860 #[doc = concat!("let _ = (", stringify!($SelfT), "::MIN + 2).strict_sub_unsigned(3);")]
861 /// ```
862 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
863 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
864 #[must_use = "this returns the result of the operation, \
865 without modifying the original"]
866 #[inline]
867 #[track_caller]
868 pub const fn strict_sub_unsigned(self, rhs: $UnsignedT) -> Self {
869 let (a, b) = self.overflowing_sub_unsigned(rhs);
870 if b { imp::overflow_panic::sub() } else { a }
871 }
872
873 /// Checked integer multiplication. Computes `self * rhs`, returning `None` if
874 /// overflow occurred.
875 ///
876 /// # Examples
877 ///
878 /// ```
879 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(1), Some(", stringify!($SelfT), "::MAX));")]
880 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")]
881 /// ```
882 #[stable(feature = "rust1", since = "1.0.0")]
883 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
884 #[must_use = "this returns the result of the operation, \
885 without modifying the original"]
886 #[inline]
887 pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
888 let (a, b) = self.overflowing_mul(rhs);
889 if intrinsics::unlikely(b) { None } else { Some(a) }
890 }
891
892 /// Strict integer multiplication. Computes `self * rhs`, panicking if
893 /// overflow occurred.
894 ///
895 /// # Panics
896 ///
897 /// ## Overflow behavior
898 ///
899 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
900 ///
901 /// # Examples
902 ///
903 /// ```
904 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.strict_mul(1), ", stringify!($SelfT), "::MAX);")]
905 /// ```
906 ///
907 /// The following panics because of overflow:
908 ///
909 /// ``` should_panic
910 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")]
911 /// ```
912 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
913 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
914 #[must_use = "this returns the result of the operation, \
915 without modifying the original"]
916 #[inline]
917 #[track_caller]
918 pub const fn strict_mul(self, rhs: Self) -> Self {
919 let (a, b) = self.overflowing_mul(rhs);
920 if b { imp::overflow_panic::mul() } else { a }
921 }
922
923 /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
924 /// cannot occur.
925 ///
926 /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling
927 /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`.
928 ///
929 /// If you're just trying to avoid the panic in debug mode, then **do not**
930 /// use this. Instead, you're looking for [`wrapping_mul`].
931 ///
932 /// # Safety
933 ///
934 /// This results in undefined behavior when
935 #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")]
936 /// i.e. when [`checked_mul`] would return `None`.
937 ///
938 /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked
939 #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")]
940 #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")]
941 #[stable(feature = "unchecked_math", since = "1.79.0")]
942 #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")]
943 #[must_use = "this returns the result of the operation, \
944 without modifying the original"]
945 #[inline(always)]
946 #[track_caller]
947 pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self {
948 assert_unsafe_precondition!(
949 check_language_ub,
950 concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"),
951 (
952 lhs: $SelfT = self,
953 rhs: $SelfT = rhs,
954 ) => !lhs.overflowing_mul(rhs).1,
955 );
956
957 // SAFETY: this is guaranteed to be safe by the caller.
958 unsafe {
959 intrinsics::unchecked_mul(self, rhs)
960 }
961 }
962
963 /// Checked integer division. Computes `self / rhs`, returning `None` if `rhs == 0`
964 /// or the division results in overflow.
965 ///
966 /// # Examples
967 ///
968 /// ```
969 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div(-1), Some(", stringify!($Max), "));")]
970 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div(-1), None);")]
971 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div(0), None);")]
972 /// ```
973 #[stable(feature = "rust1", since = "1.0.0")]
974 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
975 #[must_use = "this returns the result of the operation, \
976 without modifying the original"]
977 #[inline]
978 pub const fn checked_div(self, rhs: Self) -> Option<Self> {
979 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
980 None
981 } else {
982 // SAFETY: div by zero and by INT_MIN have been checked above
983 Some(unsafe { intrinsics::unchecked_div(self, rhs) })
984 }
985 }
986
987 /// Strict integer division. Computes `self / rhs`, panicking
988 /// if overflow occurred.
989 ///
990 /// # Panics
991 ///
992 /// This function will panic if `rhs` is zero.
993 ///
994 /// ## Overflow behavior
995 ///
996 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
997 ///
998 /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
999 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
1000 /// that is too large to represent in the type.
1001 ///
1002 /// # Examples
1003 ///
1004 /// ```
1005 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).strict_div(-1), ", stringify!($Max), ");")]
1006 /// ```
1007 ///
1008 /// The following panics because of overflow:
1009 ///
1010 /// ```should_panic
1011 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_div(-1);")]
1012 /// ```
1013 ///
1014 /// The following panics because of division by zero:
1015 ///
1016 /// ```should_panic
1017 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")]
1018 /// ```
1019 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1020 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1021 #[must_use = "this returns the result of the operation, \
1022 without modifying the original"]
1023 #[inline]
1024 #[track_caller]
1025 pub const fn strict_div(self, rhs: Self) -> Self {
1026 let (a, b) = self.overflowing_div(rhs);
1027 if b { imp::overflow_panic::div() } else { a }
1028 }
1029
1030 /// Checked Euclidean division. Computes `self.div_euclid(rhs)`,
1031 /// returning `None` if `rhs == 0` or the division results in overflow.
1032 ///
1033 /// # Examples
1034 ///
1035 /// ```
1036 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div_euclid(-1), Some(", stringify!($Max), "));")]
1037 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div_euclid(-1), None);")]
1038 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div_euclid(0), None);")]
1039 /// ```
1040 #[stable(feature = "euclidean_division", since = "1.38.0")]
1041 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1042 #[must_use = "this returns the result of the operation, \
1043 without modifying the original"]
1044 #[inline]
1045 pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
1046 // Using `&` helps LLVM see that it is the same check made in division.
1047 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
1048 None
1049 } else {
1050 Some(self.div_euclid(rhs))
1051 }
1052 }
1053
1054 /// Strict Euclidean division. Computes `self.div_euclid(rhs)`, panicking
1055 /// if overflow occurred.
1056 ///
1057 /// # Panics
1058 ///
1059 /// This function will panic if `rhs` is zero.
1060 ///
1061 /// ## Overflow behavior
1062 ///
1063 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1064 ///
1065 /// The only case where such an overflow can occur is when one divides `MIN / -1` on a signed type (where
1066 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
1067 /// that is too large to represent in the type.
1068 ///
1069 /// # Examples
1070 ///
1071 /// ```
1072 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).strict_div_euclid(-1), ", stringify!($Max), ");")]
1073 /// ```
1074 ///
1075 /// The following panics because of overflow:
1076 ///
1077 /// ```should_panic
1078 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_div_euclid(-1);")]
1079 /// ```
1080 ///
1081 /// The following panics because of division by zero:
1082 ///
1083 /// ```should_panic
1084 #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")]
1085 /// ```
1086 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1087 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1088 #[must_use = "this returns the result of the operation, \
1089 without modifying the original"]
1090 #[inline]
1091 #[track_caller]
1092 pub const fn strict_div_euclid(self, rhs: Self) -> Self {
1093 let (a, b) = self.overflowing_div_euclid(rhs);
1094 if b { imp::overflow_panic::div() } else { a }
1095 }
1096
1097 /// Checked integer division without remainder. Computes `self / rhs`,
1098 /// returning `None` if `rhs == 0`, the division results in overflow,
1099 /// or `self % rhs != 0`.
1100 ///
1101 /// # Examples
1102 ///
1103 /// ```
1104 /// #![feature(exact_div)]
1105 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).checked_div_exact(-1), Some(", stringify!($Max), "));")]
1106 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").checked_div_exact(2), None);")]
1107 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_div_exact(-1), None);")]
1108 #[doc = concat!("assert_eq!((1", stringify!($SelfT), ").checked_div_exact(0), None);")]
1109 /// ```
1110 #[unstable(
1111 feature = "exact_div",
1112 issue = "139911",
1113 )]
1114 #[must_use = "this returns the result of the operation, \
1115 without modifying the original"]
1116 #[inline]
1117 pub const fn checked_div_exact(self, rhs: Self) -> Option<Self> {
1118 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
1119 None
1120 } else {
1121 // SAFETY: division by zero and overflow are checked above
1122 unsafe {
1123 if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) {
1124 None
1125 } else {
1126 Some(intrinsics::exact_div(self, rhs))
1127 }
1128 }
1129 }
1130 }
1131
1132 /// Integer division without remainder. Computes `self / rhs`, returning `None` if `self % rhs != 0`.
1133 ///
1134 /// # Panics
1135 ///
1136 /// This function will panic if `rhs == 0`.
1137 ///
1138 /// ## Overflow behavior
1139 ///
1140 /// On overflow, this function will panic if overflow checks are enabled (default in debug
1141 /// mode) and wrap if overflow checks are disabled (default in release mode).
1142 ///
1143 /// # Examples
1144 ///
1145 /// ```
1146 /// #![feature(exact_div)]
1147 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(2), Some(32));")]
1148 #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".div_exact(32), Some(2));")]
1149 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).div_exact(-1), Some(", stringify!($Max), "));")]
1150 #[doc = concat!("assert_eq!(65", stringify!($SelfT), ".div_exact(2), None);")]
1151 /// ```
1152 /// ```should_panic
1153 /// #![feature(exact_div)]
1154 #[doc = concat!("let _ = 64", stringify!($SelfT),".div_exact(0);")]
1155 /// ```
1156 /// ```should_panic
1157 /// #![feature(exact_div)]
1158 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.div_exact(-1);")]
1159 /// ```
1160 #[unstable(
1161 feature = "exact_div",
1162 issue = "139911",
1163 )]
1164 #[must_use = "this returns the result of the operation, \
1165 without modifying the original"]
1166 #[inline]
1167 #[rustc_inherit_overflow_checks]
1168 pub const fn div_exact(self, rhs: Self) -> Option<Self> {
1169 if self % rhs != 0 {
1170 None
1171 } else {
1172 Some(self / rhs)
1173 }
1174 }
1175
1176 /// Unchecked integer division without remainder. Computes `self / rhs`.
1177 ///
1178 /// # Safety
1179 ///
1180 /// This results in undefined behavior when `rhs == 0`, `self % rhs != 0`, or
1181 #[doc = concat!("`self == ", stringify!($SelfT), "::MIN && rhs == -1`,")]
1182 /// i.e. when [`checked_div_exact`](Self::checked_div_exact) would return `None`.
1183 #[unstable(
1184 feature = "exact_div",
1185 issue = "139911",
1186 )]
1187 #[must_use = "this returns the result of the operation, \
1188 without modifying the original"]
1189 #[inline]
1190 pub const unsafe fn unchecked_div_exact(self, rhs: Self) -> Self {
1191 assert_unsafe_precondition!(
1192 check_language_ub,
1193 concat!(stringify!($SelfT), "::unchecked_div_exact cannot overflow, divide by zero, or leave a remainder"),
1194 (
1195 lhs: $SelfT = self,
1196 rhs: $SelfT = rhs,
1197 ) => rhs > 0 && lhs % rhs == 0 && (lhs != <$SelfT>::MIN || rhs != -1),
1198 );
1199 // SAFETY: Same precondition
1200 unsafe { intrinsics::exact_div(self, rhs) }
1201 }
1202
1203 /// Checked integer remainder. Computes `self % rhs`, returning `None` if
1204 /// `rhs == 0` or the division results in overflow.
1205 ///
1206 /// # Examples
1207 ///
1208 /// ```
1209 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")]
1210 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")]
1211 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_rem(-1), None);")]
1212 /// ```
1213 #[stable(feature = "wrapping", since = "1.7.0")]
1214 #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")]
1215 #[must_use = "this returns the result of the operation, \
1216 without modifying the original"]
1217 #[inline]
1218 pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
1219 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
1220 None
1221 } else {
1222 // SAFETY: div by zero and by INT_MIN have been checked above
1223 Some(unsafe { intrinsics::unchecked_rem(self, rhs) })
1224 }
1225 }
1226
1227 /// Strict integer remainder. Computes `self % rhs`, panicking if
1228 /// the division results in overflow.
1229 ///
1230 /// # Panics
1231 ///
1232 /// This function will panic if `rhs` is zero.
1233 ///
1234 /// ## Overflow behavior
1235 ///
1236 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1237 ///
1238 /// The only case where such an overflow can occur is `x % y` for `MIN / -1` on a
1239 /// signed type (where `MIN` is the negative minimal value), which is invalid due to implementation artifacts.
1240 ///
1241 /// # Examples
1242 ///
1243 /// ```
1244 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_rem(2), 1);")]
1245 /// ```
1246 ///
1247 /// The following panics because of division by zero:
1248 ///
1249 /// ```should_panic
1250 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")]
1251 /// ```
1252 ///
1253 /// The following panics because of overflow:
1254 ///
1255 /// ```should_panic
1256 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem(-1);")]
1257 /// ```
1258 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1259 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1260 #[must_use = "this returns the result of the operation, \
1261 without modifying the original"]
1262 #[inline]
1263 #[track_caller]
1264 pub const fn strict_rem(self, rhs: Self) -> Self {
1265 let (a, b) = self.overflowing_rem(rhs);
1266 if b { imp::overflow_panic::rem() } else { a }
1267 }
1268
1269 /// Checked Euclidean remainder. Computes `self.rem_euclid(rhs)`, returning `None`
1270 /// if `rhs == 0` or the division results in overflow.
1271 ///
1272 /// # Examples
1273 ///
1274 /// ```
1275 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")]
1276 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")]
1277 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_rem_euclid(-1), None);")]
1278 /// ```
1279 #[stable(feature = "euclidean_division", since = "1.38.0")]
1280 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
1281 #[must_use = "this returns the result of the operation, \
1282 without modifying the original"]
1283 #[inline]
1284 pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
1285 // Using `&` helps LLVM see that it is the same check made in division.
1286 if intrinsics::unlikely(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
1287 None
1288 } else {
1289 Some(self.rem_euclid(rhs))
1290 }
1291 }
1292
1293 /// Strict Euclidean remainder. Computes `self.rem_euclid(rhs)`, panicking if
1294 /// the division results in overflow.
1295 ///
1296 /// # Panics
1297 ///
1298 /// This function will panic if `rhs` is zero.
1299 ///
1300 /// ## Overflow behavior
1301 ///
1302 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1303 ///
1304 /// The only case where such an overflow can occur is `x % y` for `MIN / -1` on a
1305 /// signed type (where `MIN` is the negative minimal value), which is invalid due to implementation artifacts.
1306 ///
1307 /// # Examples
1308 ///
1309 /// ```
1310 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_rem_euclid(2), 1);")]
1311 /// ```
1312 ///
1313 /// The following panics because of division by zero:
1314 ///
1315 /// ```should_panic
1316 #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")]
1317 /// ```
1318 ///
1319 /// The following panics because of overflow:
1320 ///
1321 /// ```should_panic
1322 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_rem_euclid(-1);")]
1323 /// ```
1324 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1325 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1326 #[must_use = "this returns the result of the operation, \
1327 without modifying the original"]
1328 #[inline]
1329 #[track_caller]
1330 pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
1331 let (a, b) = self.overflowing_rem_euclid(rhs);
1332 if b { imp::overflow_panic::rem() } else { a }
1333 }
1334
1335 /// Checked negation. Computes `-self`, returning `None` if `self == MIN`.
1336 ///
1337 /// # Examples
1338 ///
1339 /// ```
1340 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_neg(), Some(-5));")]
1341 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_neg(), None);")]
1342 /// ```
1343 #[stable(feature = "wrapping", since = "1.7.0")]
1344 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1345 #[must_use = "this returns the result of the operation, \
1346 without modifying the original"]
1347 #[inline]
1348 pub const fn checked_neg(self) -> Option<Self> {
1349 let (a, b) = self.overflowing_neg();
1350 if intrinsics::unlikely(b) { None } else { Some(a) }
1351 }
1352
1353 /// Unchecked negation. Computes `-self`, assuming overflow cannot occur.
1354 ///
1355 /// # Safety
1356 ///
1357 /// This results in undefined behavior when
1358 #[doc = concat!("`self == ", stringify!($SelfT), "::MIN`,")]
1359 /// i.e. when [`checked_neg`] would return `None`.
1360 ///
1361 #[doc = concat!("[`checked_neg`]: ", stringify!($SelfT), "::checked_neg")]
1362 #[stable(feature = "unchecked_neg", since = "1.93.0")]
1363 #[rustc_const_stable(feature = "unchecked_neg", since = "1.93.0")]
1364 #[must_use = "this returns the result of the operation, \
1365 without modifying the original"]
1366 #[inline(always)]
1367 #[track_caller]
1368 pub const unsafe fn unchecked_neg(self) -> Self {
1369 assert_unsafe_precondition!(
1370 check_language_ub,
1371 concat!(stringify!($SelfT), "::unchecked_neg cannot overflow"),
1372 (
1373 lhs: $SelfT = self,
1374 ) => !lhs.overflowing_neg().1,
1375 );
1376
1377 // SAFETY: this is guaranteed to be safe by the caller.
1378 unsafe {
1379 intrinsics::unchecked_sub(0, self)
1380 }
1381 }
1382
1383 /// Strict negation. Computes `-self`, panicking if `self == MIN`.
1384 ///
1385 /// # Panics
1386 ///
1387 /// ## Overflow behavior
1388 ///
1389 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1390 ///
1391 /// # Examples
1392 ///
1393 /// ```
1394 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_neg(), -5);")]
1395 /// ```
1396 ///
1397 /// The following panics because of overflow:
1398 ///
1399 /// ```should_panic
1400 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_neg();")]
1401 /// ```
1402 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1403 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1404 #[must_use = "this returns the result of the operation, \
1405 without modifying the original"]
1406 #[inline]
1407 #[track_caller]
1408 pub const fn strict_neg(self) -> Self {
1409 let (a, b) = self.overflowing_neg();
1410 if b { imp::overflow_panic::neg() } else { a }
1411 }
1412
1413 /// Checked shift left. Computes `self << rhs`, returning `None` if `rhs` is larger
1414 /// than or equal to the number of bits in `self`.
1415 ///
1416 /// # Examples
1417 ///
1418 /// ```
1419 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")]
1420 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(129), None);")]
1421 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")]
1422 /// ```
1423 #[stable(feature = "wrapping", since = "1.7.0")]
1424 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1425 #[must_use = "this returns the result of the operation, \
1426 without modifying the original"]
1427 #[inline]
1428 pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
1429 // Not using overflowing_shl as that's a wrapping shift
1430 if rhs < Self::BITS {
1431 // SAFETY: just checked the RHS is in-range
1432 Some(unsafe { self.unchecked_shl(rhs) })
1433 } else {
1434 None
1435 }
1436 }
1437
1438 /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger
1439 /// than or equal to the number of bits in `self`.
1440 ///
1441 /// # Panics
1442 ///
1443 /// ## Overflow behavior
1444 ///
1445 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1446 ///
1447 /// # Examples
1448 ///
1449 /// ```
1450 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")]
1451 /// ```
1452 ///
1453 /// The following panics because of overflow:
1454 ///
1455 /// ```should_panic
1456 #[doc = concat!("let _ = 0x1", stringify!($SelfT), ".strict_shl(129);")]
1457 /// ```
1458 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1459 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1460 #[must_use = "this returns the result of the operation, \
1461 without modifying the original"]
1462 #[inline]
1463 #[track_caller]
1464 pub const fn strict_shl(self, rhs: u32) -> Self {
1465 let (a, b) = self.overflowing_shl(rhs);
1466 if b { imp::overflow_panic::shl() } else { a }
1467 }
1468
1469 /// Unchecked shift left. Computes `self << rhs`, assuming that
1470 /// `rhs` is less than the number of bits in `self`.
1471 ///
1472 /// # Safety
1473 ///
1474 /// This results in undefined behavior if `rhs` is larger than
1475 /// or equal to the number of bits in `self`,
1476 /// i.e. when [`checked_shl`] would return `None`.
1477 ///
1478 #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")]
1479 #[stable(feature = "unchecked_shifts", since = "1.93.0")]
1480 #[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
1481 #[must_use = "this returns the result of the operation, \
1482 without modifying the original"]
1483 #[inline(always)]
1484 #[track_caller]
1485 pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self {
1486 assert_unsafe_precondition!(
1487 check_language_ub,
1488 concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"),
1489 (
1490 rhs: u32 = rhs,
1491 ) => rhs < <$ActualT>::BITS,
1492 );
1493
1494 // SAFETY: this is guaranteed to be safe by the caller.
1495 unsafe {
1496 intrinsics::unchecked_shl(self, rhs)
1497 }
1498 }
1499
1500 /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`.
1501 ///
1502 /// If `rhs` is larger or equal to the number of bits in `self`,
1503 /// the entire value is shifted out, and `0` is returned.
1504 ///
1505 /// # Examples
1506 ///
1507 /// ```
1508 #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(4), 0x10);")]
1509 #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".unbounded_shl(129), 0);")]
1510 #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(0), 0b101);")]
1511 #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(1), 0b1010);")]
1512 #[doc = concat!("assert_eq!(0b101_", stringify!($SelfT), ".unbounded_shl(2), 0b10100);")]
1513 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(", stringify!($BITS), "), 0);")]
1514 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shl(1).unbounded_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
1515 #[doc = concat!("assert_eq!((-13_", stringify!($SelfT), ").unbounded_shl(", stringify!($BITS), "), 0);")]
1516 #[doc = concat!("assert_eq!((-13_", stringify!($SelfT), ").unbounded_shl(1).unbounded_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
1517 /// ```
1518 #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1519 #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1520 #[must_use = "this returns the result of the operation, \
1521 without modifying the original"]
1522 #[inline]
1523 pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{
1524 if rhs < Self::BITS {
1525 // SAFETY:
1526 // rhs is just checked to be in-range above
1527 unsafe { self.unchecked_shl(rhs) }
1528 } else {
1529 0
1530 }
1531 }
1532
1533 /// Exact shift left. Computes `self << rhs` as long as it can be reversed losslessly.
1534 ///
1535 /// Returns `None` if any bits that would be shifted out differ from the resulting sign bit
1536 /// or if `rhs` >=
1537 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1538 /// Otherwise, returns `Some(self << rhs)`.
1539 ///
1540 /// # Examples
1541 ///
1542 /// ```
1543 /// #![feature(exact_bitshifts)]
1544 ///
1545 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(4), Some(0x10));")]
1546 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(", stringify!($SelfT), "::BITS - 2), Some(1 << ", stringify!($SelfT), "::BITS - 2));")]
1547 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".shl_exact(", stringify!($SelfT), "::BITS - 1), None);")]
1548 #[doc = concat!("assert_eq!((-0x2", stringify!($SelfT), ").shl_exact(", stringify!($SelfT), "::BITS - 2), Some(-0x2 << ", stringify!($SelfT), "::BITS - 2));")]
1549 #[doc = concat!("assert_eq!((-0x2", stringify!($SelfT), ").shl_exact(", stringify!($SelfT), "::BITS - 1), None);")]
1550 /// ```
1551 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1552 #[must_use = "this returns the result of the operation, \
1553 without modifying the original"]
1554 #[inline]
1555 pub const fn shl_exact(self, rhs: u32) -> Option<$SelfT> {
1556 if rhs < self.leading_zeros() || rhs < self.leading_ones() {
1557 // SAFETY: rhs is checked above
1558 Some(unsafe { self.unchecked_shl(rhs) })
1559 } else {
1560 None
1561 }
1562 }
1563
1564 /// Unchecked exact shift left. Computes `self << rhs`, assuming the operation can be
1565 /// losslessly reversed and `rhs` cannot be larger than
1566 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1567 ///
1568 /// # Safety
1569 ///
1570 /// This results in undefined behavior when `rhs >= self.leading_zeros() && rhs >=
1571 /// self.leading_ones()` i.e. when
1572 #[doc = concat!("[`", stringify!($SelfT), "::shl_exact`]")]
1573 /// would return `None`.
1574 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1575 #[must_use = "this returns the result of the operation, \
1576 without modifying the original"]
1577 #[inline]
1578 pub const unsafe fn unchecked_shl_exact(self, rhs: u32) -> $SelfT {
1579 assert_unsafe_precondition!(
1580 check_library_ub,
1581 concat!(stringify!($SelfT), "::unchecked_shl_exact cannot shift out bits that would change the value of the first bit"),
1582 (
1583 zeros: u32 = self.leading_zeros(),
1584 ones: u32 = self.leading_ones(),
1585 rhs: u32 = rhs,
1586 ) => rhs < zeros || rhs < ones,
1587 );
1588
1589 // SAFETY: this is guaranteed to be safe by the caller
1590 unsafe { self.unchecked_shl(rhs) }
1591 }
1592
1593 /// Checked shift right. Computes `self >> rhs`, returning `None` if `rhs` is
1594 /// larger than or equal to the number of bits in `self`.
1595 ///
1596 /// # Examples
1597 ///
1598 /// ```
1599 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")]
1600 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(128), None);")]
1601 /// ```
1602 #[stable(feature = "wrapping", since = "1.7.0")]
1603 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1604 #[must_use = "this returns the result of the operation, \
1605 without modifying the original"]
1606 #[inline]
1607 pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
1608 // Not using overflowing_shr as that's a wrapping shift
1609 if rhs < Self::BITS {
1610 // SAFETY: just checked the RHS is in-range
1611 Some(unsafe { self.unchecked_shr(rhs) })
1612 } else {
1613 None
1614 }
1615 }
1616
1617 /// Strict shift right. Computes `self >> rhs`, panicking if `rhs` is
1618 /// larger than or equal to the number of bits in `self`.
1619 ///
1620 /// # Panics
1621 ///
1622 /// ## Overflow behavior
1623 ///
1624 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1625 ///
1626 /// # Examples
1627 ///
1628 /// ```
1629 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")]
1630 /// ```
1631 ///
1632 /// The following panics because of overflow:
1633 ///
1634 /// ```should_panic
1635 #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(128);")]
1636 /// ```
1637 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1638 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1639 #[must_use = "this returns the result of the operation, \
1640 without modifying the original"]
1641 #[inline]
1642 #[track_caller]
1643 pub const fn strict_shr(self, rhs: u32) -> Self {
1644 let (a, b) = self.overflowing_shr(rhs);
1645 if b { imp::overflow_panic::shr() } else { a }
1646 }
1647
1648 /// Unchecked shift right. Computes `self >> rhs`, assuming that
1649 /// `rhs` is less than the number of bits in `self`.
1650 ///
1651 /// # Safety
1652 ///
1653 /// This results in undefined behavior if `rhs` is larger than
1654 /// or equal to the number of bits in `self`,
1655 /// i.e. when [`checked_shr`] would return `None`.
1656 ///
1657 #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")]
1658 #[stable(feature = "unchecked_shifts", since = "1.93.0")]
1659 #[rustc_const_stable(feature = "unchecked_shifts", since = "1.93.0")]
1660 #[must_use = "this returns the result of the operation, \
1661 without modifying the original"]
1662 #[inline(always)]
1663 #[track_caller]
1664 pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self {
1665 assert_unsafe_precondition!(
1666 check_language_ub,
1667 concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"),
1668 (
1669 rhs: u32 = rhs,
1670 ) => rhs < <$ActualT>::BITS,
1671 );
1672
1673 // SAFETY: this is guaranteed to be safe by the caller.
1674 unsafe {
1675 intrinsics::unchecked_shr(self, rhs)
1676 }
1677 }
1678
1679 /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`.
1680 ///
1681 /// If `rhs` is larger or equal to the number of bits in `self`,
1682 /// the entire value is shifted out, which yields `0` for a positive number,
1683 /// and `-1` for a negative number.
1684 ///
1685 /// # Examples
1686 ///
1687 /// ```
1688 #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(4), 0x1);")]
1689 #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".unbounded_shr(129), 0);")]
1690 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.unbounded_shr(129), -1);")]
1691 #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(0), 0b1010);")]
1692 #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(1), 0b101);")]
1693 #[doc = concat!("assert_eq!(0b1010_", stringify!($SelfT), ".unbounded_shr(2), 0b10);")]
1694 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(", stringify!($BITS), "), 0);")]
1695 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".unbounded_shr(1).unbounded_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
1696 #[doc = concat!("assert_eq!((-13_", stringify!($SelfT), ").unbounded_shr(", stringify!($BITS), "), -1);")]
1697 #[doc = concat!("assert_eq!((-13_", stringify!($SelfT), ").unbounded_shr(1).unbounded_shr(", stringify!($BITS_MINUS_ONE), "), -1);")]
1698 /// ```
1699 #[stable(feature = "unbounded_shifts", since = "1.87.0")]
1700 #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")]
1701 #[must_use = "this returns the result of the operation, \
1702 without modifying the original"]
1703 #[inline]
1704 pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{
1705 if rhs < Self::BITS {
1706 // SAFETY:
1707 // rhs is just checked to be in-range above
1708 unsafe { self.unchecked_shr(rhs) }
1709 } else {
1710 // A shift by `Self::BITS-1` suffices for signed integers, because the sign bit is copied for each of the shifted bits.
1711
1712 // SAFETY:
1713 // `Self::BITS-1` is guaranteed to be less than `Self::BITS`
1714 unsafe { self.unchecked_shr(Self::BITS - 1) }
1715 }
1716 }
1717
1718 /// Exact shift right. Computes `self >> rhs` as long as it can be reversed losslessly.
1719 ///
1720 /// Returns `None` if any non-zero bits would be shifted out or if `rhs` >=
1721 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1722 /// Otherwise, returns `Some(self >> rhs)`.
1723 ///
1724 /// # Examples
1725 ///
1726 /// ```
1727 /// #![feature(exact_bitshifts)]
1728 ///
1729 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(4), Some(0x1));")]
1730 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".shr_exact(5), None);")]
1731 /// ```
1732 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1733 #[must_use = "this returns the result of the operation, \
1734 without modifying the original"]
1735 #[inline]
1736 pub const fn shr_exact(self, rhs: u32) -> Option<$SelfT> {
1737 if rhs <= self.trailing_zeros() && rhs < <$SelfT>::BITS {
1738 // SAFETY: rhs is checked above
1739 Some(unsafe { self.unchecked_shr(rhs) })
1740 } else {
1741 None
1742 }
1743 }
1744
1745 /// Unchecked exact shift right. Computes `self >> rhs`, assuming the operation can be
1746 /// losslessly reversed and `rhs` cannot be larger than
1747 #[doc = concat!("`", stringify!($SelfT), "::BITS`.")]
1748 ///
1749 /// # Safety
1750 ///
1751 /// This results in undefined behavior when `rhs > self.trailing_zeros() || rhs >=
1752 #[doc = concat!(stringify!($SelfT), "::BITS`")]
1753 /// i.e. when
1754 #[doc = concat!("[`", stringify!($SelfT), "::shr_exact`]")]
1755 /// would return `None`.
1756 #[unstable(feature = "exact_bitshifts", issue = "144336")]
1757 #[must_use = "this returns the result of the operation, \
1758 without modifying the original"]
1759 #[inline]
1760 pub const unsafe fn unchecked_shr_exact(self, rhs: u32) -> $SelfT {
1761 assert_unsafe_precondition!(
1762 check_library_ub,
1763 concat!(stringify!($SelfT), "::unchecked_shr_exact cannot shift out non-zero bits"),
1764 (
1765 zeros: u32 = self.trailing_zeros(),
1766 bits: u32 = <$SelfT>::BITS,
1767 rhs: u32 = rhs,
1768 ) => rhs <= zeros && rhs < bits,
1769 );
1770
1771 // SAFETY: this is guaranteed to be safe by the caller
1772 unsafe { self.unchecked_shr(rhs) }
1773 }
1774
1775 /// Checked absolute value. Computes `self.abs()`, returning `None` if
1776 /// `self == MIN`.
1777 ///
1778 /// # Examples
1779 ///
1780 /// ```
1781 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").checked_abs(), Some(5));")]
1782 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.checked_abs(), None);")]
1783 /// ```
1784 #[stable(feature = "no_panic_abs", since = "1.13.0")]
1785 #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")]
1786 #[must_use = "this returns the result of the operation, \
1787 without modifying the original"]
1788 #[inline]
1789 pub const fn checked_abs(self) -> Option<Self> {
1790 if self.is_negative() {
1791 self.checked_neg()
1792 } else {
1793 Some(self)
1794 }
1795 }
1796
1797 /// Strict absolute value. Computes `self.abs()`, panicking if
1798 /// `self == MIN`.
1799 ///
1800 /// # Panics
1801 ///
1802 /// ## Overflow behavior
1803 ///
1804 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1805 ///
1806 /// # Examples
1807 ///
1808 /// ```
1809 #[doc = concat!("assert_eq!((-5", stringify!($SelfT), ").strict_abs(), 5);")]
1810 /// ```
1811 ///
1812 /// The following panics because of overflow:
1813 ///
1814 /// ```should_panic
1815 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.strict_abs();")]
1816 /// ```
1817 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1818 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1819 #[must_use = "this returns the result of the operation, \
1820 without modifying the original"]
1821 #[inline]
1822 #[track_caller]
1823 pub const fn strict_abs(self) -> Self {
1824 if self.is_negative() {
1825 self.strict_neg()
1826 } else {
1827 self
1828 }
1829 }
1830
1831 /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if
1832 /// overflow occurred.
1833 ///
1834 /// # Examples
1835 ///
1836 /// ```
1837 #[doc = concat!("assert_eq!(8", stringify!($SelfT), ".checked_pow(2), Some(64));")]
1838 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".checked_pow(0), Some(1));")]
1839 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")]
1840 /// ```
1841
1842 #[stable(feature = "no_panic_pow", since = "1.34.0")]
1843 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
1844 #[must_use = "this returns the result of the operation, \
1845 without modifying the original"]
1846 #[inline]
1847 pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
1848 if exp == 0 {
1849 return Some(1);
1850 }
1851 let mut base = self;
1852 let mut acc: Self = 1;
1853
1854 loop {
1855 if (exp & 1) == 1 {
1856 acc = try_opt!(acc.checked_mul(base));
1857 // since exp!=0, finally the exp must be 1.
1858 if exp == 1 {
1859 return Some(acc);
1860 }
1861 }
1862 exp /= 2;
1863 base = try_opt!(base.checked_mul(base));
1864 }
1865 }
1866
1867 /// Strict exponentiation. Computes `self.pow(exp)`, panicking if
1868 /// overflow occurred.
1869 ///
1870 /// # Panics
1871 ///
1872 /// ## Overflow behavior
1873 ///
1874 /// This function will always panic on overflow, regardless of whether overflow checks are enabled.
1875 ///
1876 /// # Examples
1877 ///
1878 /// ```
1879 #[doc = concat!("assert_eq!(8", stringify!($SelfT), ".strict_pow(2), 64);")]
1880 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".strict_pow(0), 1);")]
1881 /// ```
1882 ///
1883 /// The following panics because of overflow:
1884 ///
1885 /// ```should_panic
1886 #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")]
1887 /// ```
1888 #[stable(feature = "strict_overflow_ops", since = "1.91.0")]
1889 #[rustc_const_stable(feature = "strict_overflow_ops", since = "1.91.0")]
1890 #[must_use = "this returns the result of the operation, \
1891 without modifying the original"]
1892 #[inline]
1893 #[track_caller]
1894 pub const fn strict_pow(self, mut exp: u32) -> Self {
1895 if exp == 0 {
1896 return 1;
1897 }
1898 let mut base = self;
1899 let mut acc: Self = 1;
1900
1901 loop {
1902 if (exp & 1) == 1 {
1903 acc = acc.strict_mul(base);
1904 // since exp!=0, finally the exp must be 1.
1905 if exp == 1 {
1906 return acc;
1907 }
1908 }
1909 exp /= 2;
1910 base = base.strict_mul(base);
1911 }
1912 }
1913
1914 /// Returns the integer square root of the number, rounded down.
1915 ///
1916 /// This function returns the **principal (non-negative) square root**.
1917 /// For a given number `n`, although both `x` and `-x` satisfy x<sup>2</sup> = n,
1918 /// this function always returns the non-negative value.
1919 ///
1920 /// Returns `None` if `self` is negative.
1921 ///
1922 /// # Examples
1923 ///
1924 /// ```
1925 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_isqrt(), Some(3));")]
1926 /// ```
1927 #[stable(feature = "isqrt", since = "1.84.0")]
1928 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
1929 #[must_use = "this returns the result of the operation, \
1930 without modifying the original"]
1931 #[inline]
1932 pub const fn checked_isqrt(self) -> Option<Self> {
1933 if self < 0 {
1934 None
1935 } else {
1936 // SAFETY: Input is nonnegative in this `else` branch.
1937 let result = unsafe {
1938 imp::int_sqrt::$ActualT(self as $ActualT) as $SelfT
1939 };
1940
1941 // Inform the optimizer what the range of outputs is. If
1942 // testing `core` crashes with no panic message and a
1943 // `num::int_sqrt::i*` test failed, it's because your edits
1944 // caused these assertions to become false.
1945 //
1946 // SAFETY: Integer square root is a monotonically nondecreasing
1947 // function, which means that increasing the input will never
1948 // cause the output to decrease. Thus, since the input for
1949 // nonnegative signed integers is bounded by
1950 // `[0, <$ActualT>::MAX]`, sqrt(n) will be bounded by
1951 // `[sqrt(0), sqrt(<$ActualT>::MAX)]`.
1952 unsafe {
1953 // SAFETY: `<$ActualT>::MAX` is nonnegative.
1954 const MAX_RESULT: $SelfT = unsafe {
1955 imp::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT
1956 };
1957
1958 crate::hint::assert_unchecked(result >= 0);
1959 crate::hint::assert_unchecked(result <= MAX_RESULT);
1960 }
1961
1962 Some(result)
1963 }
1964 }
1965
1966 /// Saturating integer addition. Computes `self + rhs`, saturating at the numeric
1967 /// bounds instead of overflowing.
1968 ///
1969 /// # Examples
1970 ///
1971 /// ```
1972 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")]
1973 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(100), ", stringify!($SelfT), "::MAX);")]
1974 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_add(-1), ", stringify!($SelfT), "::MIN);")]
1975 /// ```
1976
1977 #[stable(feature = "rust1", since = "1.0.0")]
1978 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
1979 #[must_use = "this returns the result of the operation, \
1980 without modifying the original"]
1981 #[inline(always)]
1982 pub const fn saturating_add(self, rhs: Self) -> Self {
1983 intrinsics::saturating_add(self, rhs)
1984 }
1985
1986 /// Saturating addition with an unsigned integer. Computes `self + rhs`,
1987 /// saturating at the numeric bounds instead of overflowing.
1988 ///
1989 /// # Examples
1990 ///
1991 /// ```
1992 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_unsigned(2), 3);")]
1993 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add_unsigned(100), ", stringify!($SelfT), "::MAX);")]
1994 /// ```
1995 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
1996 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
1997 #[must_use = "this returns the result of the operation, \
1998 without modifying the original"]
1999 #[inline]
2000 pub const fn saturating_add_unsigned(self, rhs: $UnsignedT) -> Self {
2001 // Overflow can only happen at the upper bound
2002 // We cannot use `unwrap_or` here because it is not `const`
2003 match self.checked_add_unsigned(rhs) {
2004 Some(x) => x,
2005 None => Self::MAX,
2006 }
2007 }
2008
2009 /// Saturating integer subtraction. Computes `self - rhs`, saturating at the
2010 /// numeric bounds instead of overflowing.
2011 ///
2012 /// # Examples
2013 ///
2014 /// ```
2015 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(127), -27);")]
2016 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub(100), ", stringify!($SelfT), "::MIN);")]
2017 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_sub(-1), ", stringify!($SelfT), "::MAX);")]
2018 /// ```
2019 #[stable(feature = "rust1", since = "1.0.0")]
2020 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2021 #[must_use = "this returns the result of the operation, \
2022 without modifying the original"]
2023 #[inline(always)]
2024 pub const fn saturating_sub(self, rhs: Self) -> Self {
2025 intrinsics::saturating_sub(self, rhs)
2026 }
2027
2028 /// Saturating subtraction with an unsigned integer. Computes `self - rhs`,
2029 /// saturating at the numeric bounds instead of overflowing.
2030 ///
2031 /// # Examples
2032 ///
2033 /// ```
2034 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub_unsigned(127), -27);")]
2035 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_sub_unsigned(100), ", stringify!($SelfT), "::MIN);")]
2036 /// ```
2037 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2038 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2039 #[must_use = "this returns the result of the operation, \
2040 without modifying the original"]
2041 #[inline]
2042 pub const fn saturating_sub_unsigned(self, rhs: $UnsignedT) -> Self {
2043 // Overflow can only happen at the lower bound
2044 // We cannot use `unwrap_or` here because it is not `const`
2045 match self.checked_sub_unsigned(rhs) {
2046 Some(x) => x,
2047 None => Self::MIN,
2048 }
2049 }
2050
2051 /// Saturating integer negation. Computes `-self`, returning `MAX` if `self == MIN`
2052 /// instead of overflowing.
2053 ///
2054 /// # Examples
2055 ///
2056 /// ```
2057 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_neg(), -100);")]
2058 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").saturating_neg(), 100);")]
2059 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_neg(), ", stringify!($SelfT), "::MAX);")]
2060 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_neg(), ", stringify!($SelfT), "::MIN + 1);")]
2061 /// ```
2062
2063 #[stable(feature = "saturating_neg", since = "1.45.0")]
2064 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2065 #[must_use = "this returns the result of the operation, \
2066 without modifying the original"]
2067 #[inline(always)]
2068 pub const fn saturating_neg(self) -> Self {
2069 intrinsics::saturating_sub(0, self)
2070 }
2071
2072 /// Saturating absolute value. Computes `self.abs()`, returning `MAX` if `self ==
2073 /// MIN` instead of overflowing.
2074 ///
2075 /// # Examples
2076 ///
2077 /// ```
2078 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_abs(), 100);")]
2079 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").saturating_abs(), 100);")]
2080 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_abs(), ", stringify!($SelfT), "::MAX);")]
2081 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 1).saturating_abs(), ", stringify!($SelfT), "::MAX);")]
2082 /// ```
2083
2084 #[stable(feature = "saturating_neg", since = "1.45.0")]
2085 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2086 #[must_use = "this returns the result of the operation, \
2087 without modifying the original"]
2088 #[inline]
2089 pub const fn saturating_abs(self) -> Self {
2090 if self.is_negative() {
2091 self.saturating_neg()
2092 } else {
2093 self
2094 }
2095 }
2096
2097 /// Saturating integer multiplication. Computes `self * rhs`, saturating at the
2098 /// numeric bounds instead of overflowing.
2099 ///
2100 /// # Examples
2101 ///
2102 /// ```
2103 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".saturating_mul(12), 120);")]
2104 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_mul(10), ", stringify!($SelfT), "::MAX);")]
2105 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_mul(10), ", stringify!($SelfT), "::MIN);")]
2106 /// ```
2107 #[stable(feature = "wrapping", since = "1.7.0")]
2108 #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")]
2109 #[must_use = "this returns the result of the operation, \
2110 without modifying the original"]
2111 #[inline]
2112 pub const fn saturating_mul(self, rhs: Self) -> Self {
2113 match self.checked_mul(rhs) {
2114 Some(x) => x,
2115 None => if (self < 0) == (rhs < 0) {
2116 Self::MAX
2117 } else {
2118 Self::MIN
2119 }
2120 }
2121 }
2122
2123 /// Saturating integer division. Computes `self / rhs`, saturating at the
2124 /// numeric bounds instead of overflowing.
2125 ///
2126 /// # Panics
2127 ///
2128 /// This function will panic if `rhs` is zero.
2129 ///
2130 /// # Examples
2131 ///
2132 /// ```
2133 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")]
2134 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_div(-1), ", stringify!($SelfT), "::MIN + 1);")]
2135 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_div(-1), ", stringify!($SelfT), "::MAX);")]
2136 ///
2137 /// ```
2138 #[stable(feature = "saturating_div", since = "1.58.0")]
2139 #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")]
2140 #[must_use = "this returns the result of the operation, \
2141 without modifying the original"]
2142 #[inline]
2143 pub const fn saturating_div(self, rhs: Self) -> Self {
2144 match self.overflowing_div(rhs) {
2145 (result, false) => result,
2146 (_result, true) => Self::MAX, // MIN / -1 is the only possible saturating overflow
2147 }
2148 }
2149
2150 /// Saturating integer exponentiation. Computes `self.pow(exp)`,
2151 /// saturating at the numeric bounds instead of overflowing.
2152 ///
2153 /// # Examples
2154 ///
2155 /// ```
2156 #[doc = concat!("assert_eq!((-4", stringify!($SelfT), ").saturating_pow(3), -64);")]
2157 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".saturating_pow(0), 1);")]
2158 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(2), ", stringify!($SelfT), "::MAX);")]
2159 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(3), ", stringify!($SelfT), "::MIN);")]
2160 /// ```
2161 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2162 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2163 #[must_use = "this returns the result of the operation, \
2164 without modifying the original"]
2165 #[inline]
2166 pub const fn saturating_pow(self, exp: u32) -> Self {
2167 match self.checked_pow(exp) {
2168 Some(x) => x,
2169 None if self < 0 && exp % 2 == 1 => Self::MIN,
2170 None => Self::MAX,
2171 }
2172 }
2173
2174 /// Wrapping (modular) addition. Computes `self + rhs`, wrapping around at the
2175 /// boundary of the type.
2176 ///
2177 /// # Examples
2178 ///
2179 /// ```
2180 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add(27), 127);")]
2181 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add(2), ", stringify!($SelfT), "::MIN + 1);")]
2182 /// ```
2183 #[stable(feature = "rust1", since = "1.0.0")]
2184 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2185 #[must_use = "this returns the result of the operation, \
2186 without modifying the original"]
2187 #[inline(always)]
2188 pub const fn wrapping_add(self, rhs: Self) -> Self {
2189 intrinsics::wrapping_add(self, rhs)
2190 }
2191
2192 /// Wrapping (modular) addition with an unsigned integer. Computes
2193 /// `self + rhs`, wrapping around at the boundary of the type.
2194 ///
2195 /// # Examples
2196 ///
2197 /// ```
2198 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_add_unsigned(27), 127);")]
2199 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_add_unsigned(2), ", stringify!($SelfT), "::MIN + 1);")]
2200 /// ```
2201 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2202 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2203 #[must_use = "this returns the result of the operation, \
2204 without modifying the original"]
2205 #[inline(always)]
2206 pub const fn wrapping_add_unsigned(self, rhs: $UnsignedT) -> Self {
2207 self.wrapping_add(rhs as Self)
2208 }
2209
2210 /// Wrapping (modular) subtraction. Computes `self - rhs`, wrapping around at the
2211 /// boundary of the type.
2212 ///
2213 /// # Examples
2214 ///
2215 /// ```
2216 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub(127), -127);")]
2217 #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub(", stringify!($SelfT), "::MAX), ", stringify!($SelfT), "::MAX);")]
2218 /// ```
2219 #[stable(feature = "rust1", since = "1.0.0")]
2220 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2221 #[must_use = "this returns the result of the operation, \
2222 without modifying the original"]
2223 #[inline(always)]
2224 pub const fn wrapping_sub(self, rhs: Self) -> Self {
2225 intrinsics::wrapping_sub(self, rhs)
2226 }
2227
2228 /// Wrapping (modular) subtraction with an unsigned integer. Computes
2229 /// `self - rhs`, wrapping around at the boundary of the type.
2230 ///
2231 /// # Examples
2232 ///
2233 /// ```
2234 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".wrapping_sub_unsigned(127), -127);")]
2235 #[doc = concat!("assert_eq!((-2", stringify!($SelfT), ").wrapping_sub_unsigned(", stringify!($UnsignedT), "::MAX), -1);")]
2236 /// ```
2237 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2238 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2239 #[must_use = "this returns the result of the operation, \
2240 without modifying the original"]
2241 #[inline(always)]
2242 pub const fn wrapping_sub_unsigned(self, rhs: $UnsignedT) -> Self {
2243 self.wrapping_sub(rhs as Self)
2244 }
2245
2246 /// Wrapping (modular) multiplication. Computes `self * rhs`, wrapping around at
2247 /// the boundary of the type.
2248 ///
2249 /// # Examples
2250 ///
2251 /// ```
2252 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".wrapping_mul(12), 120);")]
2253 /// assert_eq!(11i8.wrapping_mul(12), -124);
2254 /// ```
2255 #[stable(feature = "rust1", since = "1.0.0")]
2256 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2257 #[must_use = "this returns the result of the operation, \
2258 without modifying the original"]
2259 #[inline(always)]
2260 pub const fn wrapping_mul(self, rhs: Self) -> Self {
2261 intrinsics::wrapping_mul(self, rhs)
2262 }
2263
2264 /// Wrapping (modular) division. Computes `self / rhs`, wrapping around at the
2265 /// boundary of the type.
2266 ///
2267 /// The only case where such wrapping can occur is when one divides `MIN / -1` on a signed type (where
2268 /// `MIN` is the negative minimal value for the type); this is equivalent to `-MIN`, a positive value
2269 /// that is too large to represent in the type. In such a case, this function returns `MIN` itself.
2270 ///
2271 /// # Panics
2272 ///
2273 /// This function will panic if `rhs` is zero.
2274 ///
2275 /// # Examples
2276 ///
2277 /// ```
2278 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")]
2279 /// assert_eq!((-128i8).wrapping_div(-1), -128);
2280 /// ```
2281 #[stable(feature = "num_wrapping", since = "1.2.0")]
2282 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2283 #[must_use = "this returns the result of the operation, \
2284 without modifying the original"]
2285 #[inline]
2286 pub const fn wrapping_div(self, rhs: Self) -> Self {
2287 self.overflowing_div(rhs).0
2288 }
2289
2290 /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`,
2291 /// wrapping around at the boundary of the type.
2292 ///
2293 /// Wrapping will only occur in `MIN / -1` on a signed type (where `MIN` is the negative minimal value
2294 /// for the type). This is equivalent to `-MIN`, a positive value that is too large to represent in the
2295 /// type. In this case, this method returns `MIN` itself.
2296 ///
2297 /// # Panics
2298 ///
2299 /// This function will panic if `rhs` is zero.
2300 ///
2301 /// # Examples
2302 ///
2303 /// ```
2304 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")]
2305 /// assert_eq!((-128i8).wrapping_div_euclid(-1), -128);
2306 /// ```
2307 #[stable(feature = "euclidean_division", since = "1.38.0")]
2308 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2309 #[must_use = "this returns the result of the operation, \
2310 without modifying the original"]
2311 #[inline]
2312 pub const fn wrapping_div_euclid(self, rhs: Self) -> Self {
2313 self.overflowing_div_euclid(rhs).0
2314 }
2315
2316 /// Wrapping (modular) remainder. Computes `self % rhs`, wrapping around at the
2317 /// boundary of the type.
2318 ///
2319 /// Such wrap-around never actually occurs mathematically; implementation artifacts make `x % y`
2320 /// invalid for `MIN / -1` on a signed type (where `MIN` is the negative minimal value). In such a case,
2321 /// this function returns `0`.
2322 ///
2323 /// # Panics
2324 ///
2325 /// This function will panic if `rhs` is zero.
2326 ///
2327 /// # Examples
2328 ///
2329 /// ```
2330 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")]
2331 /// assert_eq!((-128i8).wrapping_rem(-1), 0);
2332 /// ```
2333 #[stable(feature = "num_wrapping", since = "1.2.0")]
2334 #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")]
2335 #[must_use = "this returns the result of the operation, \
2336 without modifying the original"]
2337 #[inline]
2338 pub const fn wrapping_rem(self, rhs: Self) -> Self {
2339 self.overflowing_rem(rhs).0
2340 }
2341
2342 /// Wrapping Euclidean remainder. Computes `self.rem_euclid(rhs)`, wrapping around
2343 /// at the boundary of the type.
2344 ///
2345 /// Wrapping will only occur in `MIN % -1` on a signed type (where `MIN` is the negative minimal value
2346 /// for the type). In this case, this method returns 0.
2347 ///
2348 /// # Panics
2349 ///
2350 /// This function will panic if `rhs` is zero.
2351 ///
2352 /// # Examples
2353 ///
2354 /// ```
2355 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")]
2356 /// assert_eq!((-128i8).wrapping_rem_euclid(-1), 0);
2357 /// ```
2358 #[stable(feature = "euclidean_division", since = "1.38.0")]
2359 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2360 #[must_use = "this returns the result of the operation, \
2361 without modifying the original"]
2362 #[inline]
2363 pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self {
2364 self.overflowing_rem_euclid(rhs).0
2365 }
2366
2367 /// Wrapping (modular) negation. Computes `-self`, wrapping around at the boundary
2368 /// of the type.
2369 ///
2370 /// The only case where such wrapping can occur is when one negates `MIN` on a signed type (where `MIN`
2371 /// is the negative minimal value for the type); this is a positive value that is too large to represent
2372 /// in the type. In such a case, this function returns `MIN` itself.
2373 ///
2374 /// # Examples
2375 ///
2376 /// ```
2377 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_neg(), -100);")]
2378 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").wrapping_neg(), 100);")]
2379 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.wrapping_neg(), ", stringify!($SelfT), "::MIN);")]
2380 /// ```
2381 #[stable(feature = "num_wrapping", since = "1.2.0")]
2382 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2383 #[must_use = "this returns the result of the operation, \
2384 without modifying the original"]
2385 #[inline(always)]
2386 pub const fn wrapping_neg(self) -> Self {
2387 (0 as $SelfT).wrapping_sub(self)
2388 }
2389
2390 /// Panic-free bitwise shift-left; yields `self << mask(rhs)`, where `mask` removes
2391 /// any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type.
2392 ///
2393 /// Beware that, unlike most other `wrapping_*` methods on integers, this
2394 /// does *not* give the same result as doing the shift in infinite precision
2395 /// then truncating as needed. The behaviour matches what shift instructions
2396 /// do on many processors, and is what the `<<` operator does when overflow
2397 /// checks are disabled, but numerically it's weird. Consider, instead,
2398 /// using [`Self::unbounded_shl`] which has nicer behaviour.
2399 ///
2400 /// Note that this is *not* the same as a rotate-left; the RHS of a wrapping shift-left is restricted to
2401 /// the range of the type, rather than the bits shifted out of the LHS being returned to the other end.
2402 /// The primitive integer types all implement a [`rotate_left`](Self::rotate_left) function,
2403 /// which may be what you want instead.
2404 ///
2405 /// # Examples
2406 ///
2407 /// ```
2408 #[doc = concat!("assert_eq!((-1_", stringify!($SelfT), ").wrapping_shl(7), -128);")]
2409 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(", stringify!($BITS), "), 42);")]
2410 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shl(1).wrapping_shl(", stringify!($BITS_MINUS_ONE), "), 0);")]
2411 #[doc = concat!("assert_eq!((-1_", stringify!($SelfT), ").wrapping_shl(128), -1);")]
2412 #[doc = concat!("assert_eq!(5_", stringify!($SelfT), ".wrapping_shl(1025), 10);")]
2413 /// ```
2414 #[stable(feature = "num_wrapping", since = "1.2.0")]
2415 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2416 #[must_use = "this returns the result of the operation, \
2417 without modifying the original"]
2418 #[inline(always)]
2419 pub const fn wrapping_shl(self, rhs: u32) -> Self {
2420 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2421 // out of bounds
2422 unsafe {
2423 self.unchecked_shl(rhs & (Self::BITS - 1))
2424 }
2425 }
2426
2427 /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`, where `mask`
2428 /// removes any high-order bits of `rhs` that would cause the shift to exceed the bitwidth of the type.
2429 ///
2430 /// Beware that, unlike most other `wrapping_*` methods on integers, this
2431 /// does *not* give the same result as doing the shift in infinite precision
2432 /// then truncating as needed. The behaviour matches what shift instructions
2433 /// do on many processors, and is what the `>>` operator does when overflow
2434 /// checks are disabled, but numerically it's weird. Consider, instead,
2435 /// using [`Self::unbounded_shr`] which has nicer behaviour.
2436 ///
2437 /// Note that this is *not* the same as a rotate-right; the RHS of a wrapping shift-right is restricted
2438 /// to the range of the type, rather than the bits shifted out of the LHS being returned to the other
2439 /// end. The primitive integer types all implement a [`rotate_right`](Self::rotate_right) function,
2440 /// which may be what you want instead.
2441 ///
2442 /// # Examples
2443 ///
2444 /// ```
2445 #[doc = concat!("assert_eq!((-128_", stringify!($SelfT), ").wrapping_shr(7), -1);")]
2446 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(", stringify!($BITS), "), 42);")]
2447 #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_shr(1).wrapping_shr(", stringify!($BITS_MINUS_ONE), "), 0);")]
2448 /// assert_eq!((-128_i16).wrapping_shr(64), -128);
2449 #[doc = concat!("assert_eq!(10_", stringify!($SelfT), ".wrapping_shr(1025), 5);")]
2450 /// ```
2451 #[stable(feature = "num_wrapping", since = "1.2.0")]
2452 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2453 #[must_use = "this returns the result of the operation, \
2454 without modifying the original"]
2455 #[inline(always)]
2456 pub const fn wrapping_shr(self, rhs: u32) -> Self {
2457 // SAFETY: the masking by the bitsize of the type ensures that we do not shift
2458 // out of bounds
2459 unsafe {
2460 self.unchecked_shr(rhs & (Self::BITS - 1))
2461 }
2462 }
2463
2464 /// Wrapping (modular) absolute value. Computes `self.abs()`, wrapping around at
2465 /// the boundary of the type.
2466 ///
2467 /// The only case where such wrapping can occur is when one takes the absolute value of the negative
2468 /// minimal value for the type; this is a positive value that is too large to represent in the type. In
2469 /// such a case, this function returns `MIN` itself.
2470 ///
2471 /// # Examples
2472 ///
2473 /// ```
2474 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_abs(), 100);")]
2475 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").wrapping_abs(), 100);")]
2476 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.wrapping_abs(), ", stringify!($SelfT), "::MIN);")]
2477 /// assert_eq!((-128i8).wrapping_abs() as u8, 128);
2478 /// ```
2479 #[stable(feature = "no_panic_abs", since = "1.13.0")]
2480 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2481 #[must_use = "this returns the result of the operation, \
2482 without modifying the original"]
2483 #[allow(unused_attributes)]
2484 #[inline]
2485 pub const fn wrapping_abs(self) -> Self {
2486 if self.is_negative() {
2487 self.wrapping_neg()
2488 } else {
2489 self
2490 }
2491 }
2492
2493 /// Computes the absolute value of `self` without any wrapping
2494 /// or panicking.
2495 ///
2496 ///
2497 /// # Examples
2498 ///
2499 /// ```
2500 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".unsigned_abs(), 100", stringify!($UnsignedT), ");")]
2501 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").unsigned_abs(), 100", stringify!($UnsignedT), ");")]
2502 /// assert_eq!((-128i8).unsigned_abs(), 128u8);
2503 /// ```
2504 #[stable(feature = "unsigned_abs", since = "1.51.0")]
2505 #[rustc_const_stable(feature = "unsigned_abs", since = "1.51.0")]
2506 #[must_use = "this returns the result of the operation, \
2507 without modifying the original"]
2508 #[inline]
2509 pub const fn unsigned_abs(self) -> $UnsignedT {
2510 self.wrapping_abs() as $UnsignedT
2511 }
2512
2513 /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`,
2514 /// wrapping around at the boundary of the type.
2515 ///
2516 /// # Examples
2517 ///
2518 /// ```
2519 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(4), 81);")]
2520 /// assert_eq!(3i8.wrapping_pow(5), -13);
2521 /// assert_eq!(3i8.wrapping_pow(6), -39);
2522 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_pow(0), 1);")]
2523 /// ```
2524 #[stable(feature = "no_panic_pow", since = "1.34.0")]
2525 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
2526 #[must_use = "this returns the result of the operation, \
2527 without modifying the original"]
2528 #[inline]
2529 pub const fn wrapping_pow(self, mut exp: u32) -> Self {
2530 if exp == 0 {
2531 return 1;
2532 }
2533 let mut base = self;
2534 let mut acc: Self = 1;
2535
2536 if intrinsics::is_val_statically_known(exp) {
2537 while exp > 1 {
2538 if (exp & 1) == 1 {
2539 acc = acc.wrapping_mul(base);
2540 }
2541 exp /= 2;
2542 base = base.wrapping_mul(base);
2543 }
2544
2545 // since exp!=0, finally the exp must be 1.
2546 // Deal with the final bit of the exponent separately, since
2547 // squaring the base afterwards is not necessary.
2548 acc.wrapping_mul(base)
2549 } else {
2550 // This is faster than the above when the exponent is not known
2551 // at compile time. We can't use the same code for the constant
2552 // exponent case because LLVM is currently unable to unroll
2553 // this loop.
2554 loop {
2555 if (exp & 1) == 1 {
2556 acc = acc.wrapping_mul(base);
2557 // since exp!=0, finally the exp must be 1.
2558 if exp == 1 {
2559 return acc;
2560 }
2561 }
2562 exp /= 2;
2563 base = base.wrapping_mul(base);
2564 }
2565 }
2566 }
2567
2568 /// Calculates `self` + `rhs`.
2569 ///
2570 /// Returns a tuple of the addition along with a boolean indicating
2571 /// whether an arithmetic overflow would occur. If an overflow would have
2572 /// occurred then the wrapped value is returned (negative if overflowed
2573 /// above [`MAX`](Self::MAX), non-negative if below [`MIN`](Self::MIN)).
2574 ///
2575 /// # Examples
2576 ///
2577 /// ```
2578 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")]
2579 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (", stringify!($SelfT), "::MIN, true));")]
2580 /// ```
2581 #[stable(feature = "wrapping", since = "1.7.0")]
2582 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2583 #[must_use = "this returns the result of the operation, \
2584 without modifying the original"]
2585 #[inline(always)]
2586 pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) {
2587 let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT);
2588 (a as Self, b)
2589 }
2590
2591 /// Calculates `self` + `rhs` + `carry` and checks for overflow.
2592 ///
2593 /// Performs "ternary addition" of two integer operands and a carry-in
2594 /// bit, and returns a tuple of the sum along with a boolean indicating
2595 /// whether an arithmetic overflow would occur. On overflow, the wrapped
2596 /// value is returned.
2597 ///
2598 /// This allows chaining together multiple additions to create a wider
2599 /// addition, and can be useful for bignum addition. This method should
2600 /// only be used for the most significant word; for the less significant
2601 /// words the unsigned method
2602 #[doc = concat!("[`", stringify!($UnsignedT), "::carrying_add`]")]
2603 /// should be used.
2604 ///
2605 /// The output boolean returned by this method is *not* a carry flag,
2606 /// and should *not* be added to a more significant word.
2607 ///
2608 /// If overflow occurred, the wrapped value is returned (negative if overflowed
2609 /// above [`MAX`](Self::MAX), non-negative if below [`MIN`](Self::MIN)).
2610 ///
2611 /// If the input carry is false, this method is equivalent to
2612 /// [`overflowing_add`](Self::overflowing_add).
2613 ///
2614 /// # Examples
2615 ///
2616 /// ```
2617 /// #![feature(signed_bigint_helpers)]
2618 /// // Only the most significant word is signed.
2619 /// //
2620 #[doc = concat!("// 10 MAX (a = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2621 #[doc = concat!("// + -5 9 (b = -5 × 2^", stringify!($BITS), " + 9)")]
2622 /// // ---------
2623 #[doc = concat!("// 6 8 (sum = 6 × 2^", stringify!($BITS), " + 8)")]
2624 ///
2625 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (10, ", stringify!($UnsignedT), "::MAX);")]
2626 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (-5, 9);")]
2627 /// let carry0 = false;
2628 ///
2629 #[doc = concat!("// ", stringify!($UnsignedT), "::carrying_add for the less significant words")]
2630 /// let (sum0, carry1) = a0.carrying_add(b0, carry0);
2631 /// assert_eq!(carry1, true);
2632 ///
2633 #[doc = concat!("// ", stringify!($SelfT), "::carrying_add for the most significant word")]
2634 /// let (sum1, overflow) = a1.carrying_add(b1, carry1);
2635 /// assert_eq!(overflow, false);
2636 ///
2637 /// assert_eq!((sum1, sum0), (6, 8));
2638 /// ```
2639 #[unstable(feature = "signed_bigint_helpers", issue = "151989")]
2640 #[must_use = "this returns the result of the operation, \
2641 without modifying the original"]
2642 #[inline]
2643 pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) {
2644 // note: longer-term this should be done via an intrinsic.
2645 // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
2646 let (a, b) = self.overflowing_add(rhs);
2647 let (c, d) = a.overflowing_add(carry as $SelfT);
2648 (c, b != d)
2649 }
2650
2651 /// Calculates `self` + `rhs` with an unsigned `rhs`.
2652 ///
2653 /// Returns a tuple of the addition along with a boolean indicating
2654 /// whether an arithmetic overflow would occur. If an overflow would
2655 /// have occurred then the wrapped value is returned.
2656 ///
2657 /// # Examples
2658 ///
2659 /// ```
2660 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_unsigned(2), (3, false));")]
2661 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_add_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MAX, false));")]
2662 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_unsigned(3), (", stringify!($SelfT), "::MIN, true));")]
2663 /// ```
2664 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2665 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2666 #[must_use = "this returns the result of the operation, \
2667 without modifying the original"]
2668 #[inline]
2669 pub const fn overflowing_add_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
2670 let rhs = rhs as Self;
2671 let (res, overflowed) = self.overflowing_add(rhs);
2672 (res, overflowed ^ (rhs < 0))
2673 }
2674
2675 /// Calculates `self` - `rhs`.
2676 ///
2677 /// Returns a tuple of the subtraction along with a boolean indicating whether an arithmetic overflow
2678 /// would occur. If an overflow would have occurred then the wrapped value is returned
2679 /// (negative if overflowed above [`MAX`](Self::MAX), non-negative if below [`MIN`](Self::MIN)).
2680 ///
2681 /// # Examples
2682 ///
2683 /// ```
2684 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")]
2685 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")]
2686 /// ```
2687 #[stable(feature = "wrapping", since = "1.7.0")]
2688 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2689 #[must_use = "this returns the result of the operation, \
2690 without modifying the original"]
2691 #[inline(always)]
2692 pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
2693 let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT);
2694 (a as Self, b)
2695 }
2696
2697 /// Calculates `self` − `rhs` − `borrow` and checks for
2698 /// overflow.
2699 ///
2700 /// Performs "ternary subtraction" by subtracting both an integer
2701 /// operand and a borrow-in bit from `self`, and returns a tuple of the
2702 /// difference along with a boolean indicating whether an arithmetic
2703 /// overflow would occur. On overflow, the wrapped value is returned.
2704 ///
2705 /// This allows chaining together multiple subtractions to create a
2706 /// wider subtraction, and can be useful for bignum subtraction. This
2707 /// method should only be used for the most significant word; for the
2708 /// less significant words the unsigned method
2709 #[doc = concat!("[`", stringify!($UnsignedT), "::borrowing_sub`]")]
2710 /// should be used.
2711 ///
2712 /// The output boolean returned by this method is *not* a borrow flag,
2713 /// and should *not* be subtracted from a more significant word.
2714 ///
2715 /// If overflow occurred, the wrapped value is returned (negative if overflowed
2716 /// above [`MAX`](Self::MAX), non-negative if below [`MIN`](Self::MIN)).
2717 ///
2718 /// If the input borrow is false, this method is equivalent to
2719 /// [`overflowing_sub`](Self::overflowing_sub).
2720 ///
2721 /// # Examples
2722 ///
2723 /// ```
2724 /// #![feature(signed_bigint_helpers)]
2725 /// // Only the most significant word is signed.
2726 /// //
2727 #[doc = concat!("// 6 8 (a = 6 × 2^", stringify!($BITS), " + 8)")]
2728 #[doc = concat!("// - -5 9 (b = -5 × 2^", stringify!($BITS), " + 9)")]
2729 /// // ---------
2730 #[doc = concat!("// 10 MAX (diff = 10 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")]
2731 ///
2732 #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (6, 8);")]
2733 #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($UnsignedT), ") = (-5, 9);")]
2734 /// let borrow0 = false;
2735 ///
2736 #[doc = concat!("// ", stringify!($UnsignedT), "::borrowing_sub for the less significant words")]
2737 /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0);
2738 /// assert_eq!(borrow1, true);
2739 ///
2740 #[doc = concat!("// ", stringify!($SelfT), "::borrowing_sub for the most significant word")]
2741 /// let (diff1, overflow) = a1.borrowing_sub(b1, borrow1);
2742 /// assert_eq!(overflow, false);
2743 ///
2744 #[doc = concat!("assert_eq!((diff1, diff0), (10, ", stringify!($UnsignedT), "::MAX));")]
2745 /// ```
2746 #[unstable(feature = "signed_bigint_helpers", issue = "151989")]
2747 #[must_use = "this returns the result of the operation, \
2748 without modifying the original"]
2749 #[inline]
2750 pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) {
2751 // note: longer-term this should be done via an intrinsic.
2752 // note: no intermediate overflow is required (https://github.com/rust-lang/rust/issues/85532#issuecomment-1032214946).
2753 let (a, b) = self.overflowing_sub(rhs);
2754 let (c, d) = a.overflowing_sub(borrow as $SelfT);
2755 (c, b != d)
2756 }
2757
2758 /// Calculates `self` - `rhs` with an unsigned `rhs`.
2759 ///
2760 /// Returns a tuple of the subtraction along with a boolean indicating
2761 /// whether an arithmetic overflow would occur. If an overflow would
2762 /// have occurred then the wrapped value is returned.
2763 ///
2764 /// # Examples
2765 ///
2766 /// ```
2767 #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_unsigned(2), (-1, false));")]
2768 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).overflowing_sub_unsigned(", stringify!($UnsignedT), "::MAX), (", stringify!($SelfT), "::MIN, false));")]
2769 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN + 2).overflowing_sub_unsigned(3), (", stringify!($SelfT), "::MAX, true));")]
2770 /// ```
2771 #[stable(feature = "mixed_integer_ops", since = "1.66.0")]
2772 #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")]
2773 #[must_use = "this returns the result of the operation, \
2774 without modifying the original"]
2775 #[inline]
2776 pub const fn overflowing_sub_unsigned(self, rhs: $UnsignedT) -> (Self, bool) {
2777 let rhs = rhs as Self;
2778 let (res, overflowed) = self.overflowing_sub(rhs);
2779 (res, overflowed ^ (rhs < 0))
2780 }
2781
2782 /// Calculates the multiplication of `self` and `rhs`.
2783 ///
2784 /// Returns a tuple of the multiplication along with a boolean indicating whether an arithmetic overflow
2785 /// would occur. If an overflow would have occurred then the wrapped value is returned.
2786 ///
2787 /// # Examples
2788 ///
2789 /// ```
2790 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_mul(2), (10, false));")]
2791 /// assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));
2792 /// ```
2793 #[stable(feature = "wrapping", since = "1.7.0")]
2794 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
2795 #[must_use = "this returns the result of the operation, \
2796 without modifying the original"]
2797 #[inline(always)]
2798 pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
2799 let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT);
2800 (a as Self, b)
2801 }
2802
2803 /// Calculates the complete product `self * rhs` without the possibility to overflow.
2804 ///
2805 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2806 /// of the result as two separate values, in that order.
2807 ///
2808 /// If you also need to add a carry to the wide result, then you want
2809 /// [`Self::carrying_mul`] instead.
2810 ///
2811 /// # Examples
2812 ///
2813 /// Please note that this example is shared among integer types, which is why `i32` is used.
2814 ///
2815 /// ```
2816 /// #![feature(widening_mul)]
2817 /// assert_eq!(5i32.widening_mul(-2), (4294967286, -1));
2818 /// assert_eq!(1_000_000_000i32.widening_mul(-10), (2884901888, -3));
2819 /// ```
2820 #[unstable(feature = "widening_mul", issue = "152016")]
2821 #[rustc_const_unstable(feature = "widening_mul", issue = "152016")]
2822 #[must_use = "this returns the result of the operation, \
2823 without modifying the original"]
2824 #[inline]
2825 pub const fn widening_mul(self, rhs: Self) -> ($UnsignedT, Self) {
2826 Self::carrying_mul_add(self, rhs, 0, 0)
2827 }
2828
2829 /// Calculates the "full multiplication" `self * rhs + carry`
2830 /// without the possibility to overflow.
2831 ///
2832 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2833 /// of the result as two separate values, in that order.
2834 ///
2835 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2836 /// additional amount of overflow. This allows for chaining together multiple
2837 /// multiplications to create "big integers" which represent larger values.
2838 ///
2839 /// If you don't need the `carry`, then you can use [`Self::widening_mul`] instead.
2840 ///
2841 /// # Examples
2842 ///
2843 /// Please note that this example is shared among integer types, which is why `i32` is used.
2844 ///
2845 /// ```
2846 /// #![feature(signed_bigint_helpers)]
2847 /// assert_eq!(5i32.carrying_mul(-2, 0), (4294967286, -1));
2848 /// assert_eq!(5i32.carrying_mul(-2, 10), (0, 0));
2849 /// assert_eq!(1_000_000_000i32.carrying_mul(-10, 0), (2884901888, -3));
2850 /// assert_eq!(1_000_000_000i32.carrying_mul(-10, 10), (2884901898, -3));
2851 #[doc = concat!("assert_eq!(",
2852 stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2853 "(", stringify!($SelfT), "::MAX.unsigned_abs() + 1, ", stringify!($SelfT), "::MAX / 2));"
2854 )]
2855 /// ```
2856 #[unstable(feature = "signed_bigint_helpers", issue = "151989")]
2857 #[rustc_const_unstable(feature = "signed_bigint_helpers", issue = "151989")]
2858 #[must_use = "this returns the result of the operation, \
2859 without modifying the original"]
2860 #[inline]
2861 pub const fn carrying_mul(self, rhs: Self, carry: Self) -> ($UnsignedT, Self) {
2862 Self::carrying_mul_add(self, rhs, carry, 0)
2863 }
2864
2865 /// Calculates the "full multiplication" `self * rhs + carry + add`
2866 /// without the possibility to overflow.
2867 ///
2868 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
2869 /// of the result as two separate values, in that order.
2870 ///
2871 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
2872 /// additional amount of overflow. This allows for chaining together multiple
2873 /// multiplications to create "big integers" which represent larger values.
2874 ///
2875 /// If you don't need either `carry`, then you can use [`Self::widening_mul`] instead,
2876 /// and if you only need one `carry`, then you can use [`Self::carrying_mul`] instead.
2877 ///
2878 /// # Examples
2879 ///
2880 /// Please note that this example is shared among integer types, which is why `i32` is used.
2881 ///
2882 /// ```
2883 /// #![feature(signed_bigint_helpers)]
2884 /// assert_eq!(5i32.carrying_mul_add(-2, 0, 0), (4294967286, -1));
2885 /// assert_eq!(5i32.carrying_mul_add(-2, 10, 10), (10, 0));
2886 /// assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 0, 0), (2884901888, -3));
2887 /// assert_eq!(1_000_000_000i32.carrying_mul_add(-10, 10, 10), (2884901908, -3));
2888 #[doc = concat!("assert_eq!(",
2889 stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ",
2890 "(", stringify!($UnsignedT), "::MAX, ", stringify!($SelfT), "::MAX / 2));"
2891 )]
2892 /// ```
2893 #[unstable(feature = "signed_bigint_helpers", issue = "151989")]
2894 #[rustc_const_unstable(feature = "signed_bigint_helpers", issue = "151989")]
2895 #[must_use = "this returns the result of the operation, \
2896 without modifying the original"]
2897 #[inline]
2898 pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> ($UnsignedT, Self) {
2899 intrinsics::carrying_mul_add(self, rhs, carry, add)
2900 }
2901
2902 /// Calculates the divisor when `self` is divided by `rhs`.
2903 ///
2904 /// Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
2905 /// occur. If an overflow would occur then self is returned.
2906 ///
2907 /// # Panics
2908 ///
2909 /// This function will panic if `rhs` is zero.
2910 ///
2911 /// # Examples
2912 ///
2913 /// ```
2914 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")]
2915 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div(-1), (", stringify!($SelfT), "::MIN, true));")]
2916 /// ```
2917 #[inline]
2918 #[stable(feature = "wrapping", since = "1.7.0")]
2919 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2920 #[must_use = "this returns the result of the operation, \
2921 without modifying the original"]
2922 pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
2923 // Using `&` helps LLVM see that it is the same check made in division.
2924 if intrinsics::unlikely((self == Self::MIN) & (rhs == -1)) {
2925 (self, true)
2926 } else {
2927 (self / rhs, false)
2928 }
2929 }
2930
2931 /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`.
2932 ///
2933 /// Returns a tuple of the divisor along with a boolean indicating whether an arithmetic overflow would
2934 /// occur. If an overflow would occur then `self` is returned.
2935 ///
2936 /// # Panics
2937 ///
2938 /// This function will panic if `rhs` is zero.
2939 ///
2940 /// # Examples
2941 ///
2942 /// ```
2943 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")]
2944 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div_euclid(-1), (", stringify!($SelfT), "::MIN, true));")]
2945 /// ```
2946 #[inline]
2947 #[stable(feature = "euclidean_division", since = "1.38.0")]
2948 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
2949 #[must_use = "this returns the result of the operation, \
2950 without modifying the original"]
2951 pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
2952 // Using `&` helps LLVM see that it is the same check made in division.
2953 if intrinsics::unlikely((self == Self::MIN) & (rhs == -1)) {
2954 (self, true)
2955 } else {
2956 (self.div_euclid(rhs), false)
2957 }
2958 }
2959
2960 /// Calculates the remainder when `self` is divided by `rhs`.
2961 ///
2962 /// Returns a tuple of the remainder after dividing along with a boolean indicating whether an
2963 /// arithmetic overflow would occur. If an overflow would occur then 0 is returned.
2964 ///
2965 /// # Panics
2966 ///
2967 /// This function will panic if `rhs` is zero.
2968 ///
2969 /// # Examples
2970 ///
2971 /// ```
2972 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")]
2973 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem(-1), (0, true));")]
2974 /// ```
2975 #[inline]
2976 #[stable(feature = "wrapping", since = "1.7.0")]
2977 #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")]
2978 #[must_use = "this returns the result of the operation, \
2979 without modifying the original"]
2980 pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
2981 if intrinsics::unlikely(rhs == -1) {
2982 (0, self == Self::MIN)
2983 } else {
2984 (self % rhs, false)
2985 }
2986 }
2987
2988
2989 /// Overflowing Euclidean remainder. Calculates `self.rem_euclid(rhs)`.
2990 ///
2991 /// Returns a tuple of the remainder after dividing along with a boolean indicating whether an
2992 /// arithmetic overflow would occur. If an overflow would occur then 0 is returned.
2993 ///
2994 /// # Panics
2995 ///
2996 /// This function will panic if `rhs` is zero.
2997 ///
2998 /// # Examples
2999 ///
3000 /// ```
3001 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")]
3002 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem_euclid(-1), (0, true));")]
3003 /// ```
3004 #[stable(feature = "euclidean_division", since = "1.38.0")]
3005 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3006 #[must_use = "this returns the result of the operation, \
3007 without modifying the original"]
3008 #[inline]
3009 #[track_caller]
3010 pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
3011 if intrinsics::unlikely(rhs == -1) {
3012 (0, self == Self::MIN)
3013 } else {
3014 (self.rem_euclid(rhs), false)
3015 }
3016 }
3017
3018
3019 /// Negates self, overflowing if this is equal to the minimum value.
3020 ///
3021 /// Returns a tuple of the negated version of self along with a boolean indicating whether an overflow
3022 /// happened. If `self` is the minimum value (e.g., `i32::MIN` for values of type `i32`), then the
3023 /// minimum value will be returned again and `true` will be returned for an overflow happening.
3024 ///
3025 /// # Examples
3026 ///
3027 /// ```
3028 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2, false));")]
3029 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.overflowing_neg(), (", stringify!($SelfT), "::MIN, true));")]
3030 /// ```
3031 #[inline]
3032 #[stable(feature = "wrapping", since = "1.7.0")]
3033 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3034 #[must_use = "this returns the result of the operation, \
3035 without modifying the original"]
3036 #[allow(unused_attributes)]
3037 pub const fn overflowing_neg(self) -> (Self, bool) {
3038 if intrinsics::unlikely(self == Self::MIN) {
3039 (Self::MIN, true)
3040 } else {
3041 (-self, false)
3042 }
3043 }
3044
3045 /// Shifts self left by `rhs` bits.
3046 ///
3047 /// Returns a tuple of the shifted version of self along with a boolean indicating whether the shift
3048 /// value was larger than or equal to the number of bits. If the shift value is too large, then value is
3049 /// masked (N-1) where N is the number of bits, and this value is then used to perform the shift.
3050 ///
3051 /// # Examples
3052 ///
3053 /// ```
3054 #[doc = concat!("assert_eq!(0x1", stringify!($SelfT),".overflowing_shl(4), (0x10, false));")]
3055 /// assert_eq!(0x1i32.overflowing_shl(36), (0x10, true));
3056 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")]
3057 /// ```
3058 #[stable(feature = "wrapping", since = "1.7.0")]
3059 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3060 #[must_use = "this returns the result of the operation, \
3061 without modifying the original"]
3062 #[inline]
3063 pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
3064 (self.wrapping_shl(rhs), rhs >= Self::BITS)
3065 }
3066
3067 /// Shifts self right by `rhs` bits.
3068 ///
3069 /// Returns a tuple of the shifted version of self along with a boolean indicating whether the shift
3070 /// value was larger than or equal to the number of bits. If the shift value is too large, then value is
3071 /// masked (N-1) where N is the number of bits, and this value is then used to perform the shift.
3072 ///
3073 /// # Examples
3074 ///
3075 /// ```
3076 #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")]
3077 /// assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
3078 /// ```
3079 #[stable(feature = "wrapping", since = "1.7.0")]
3080 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3081 #[must_use = "this returns the result of the operation, \
3082 without modifying the original"]
3083 #[inline]
3084 pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
3085 (self.wrapping_shr(rhs), rhs >= Self::BITS)
3086 }
3087
3088 /// Computes the absolute value of `self`.
3089 ///
3090 /// Returns a tuple of the absolute version of self along with a boolean indicating whether an overflow
3091 /// happened. If self is the minimum value
3092 #[doc = concat!("(e.g., ", stringify!($SelfT), "::MIN for values of type ", stringify!($SelfT), "),")]
3093 /// then the minimum value will be returned again and true will be returned
3094 /// for an overflow happening.
3095 ///
3096 /// # Examples
3097 ///
3098 /// ```
3099 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".overflowing_abs(), (10, false));")]
3100 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").overflowing_abs(), (10, false));")]
3101 #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MIN).overflowing_abs(), (", stringify!($SelfT), "::MIN, true));")]
3102 /// ```
3103 #[stable(feature = "no_panic_abs", since = "1.13.0")]
3104 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3105 #[must_use = "this returns the result of the operation, \
3106 without modifying the original"]
3107 #[inline]
3108 pub const fn overflowing_abs(self) -> (Self, bool) {
3109 (self.wrapping_abs(), self == Self::MIN)
3110 }
3111
3112 /// Raises self to the power of `exp`, using exponentiation by squaring.
3113 ///
3114 /// Returns a tuple of the exponentiation along with a bool indicating
3115 /// whether an overflow happened.
3116 ///
3117 /// # Examples
3118 ///
3119 /// ```
3120 #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(4), (81, false));")]
3121 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".overflowing_pow(0), (1, false));")]
3122 /// assert_eq!(3i8.overflowing_pow(5), (-13, true));
3123 /// ```
3124 #[stable(feature = "no_panic_pow", since = "1.34.0")]
3125 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3126 #[must_use = "this returns the result of the operation, \
3127 without modifying the original"]
3128 #[inline]
3129 pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
3130 if exp == 0 {
3131 return (1,false);
3132 }
3133 let mut base = self;
3134 let mut acc: Self = 1;
3135 let mut overflown = false;
3136 // Scratch space for storing results of overflowing_mul.
3137 let mut r;
3138
3139 loop {
3140 if (exp & 1) == 1 {
3141 r = acc.overflowing_mul(base);
3142 // since exp!=0, finally the exp must be 1.
3143 if exp == 1 {
3144 r.1 |= overflown;
3145 return r;
3146 }
3147 acc = r.0;
3148 overflown |= r.1;
3149 }
3150 exp /= 2;
3151 r = base.overflowing_mul(base);
3152 base = r.0;
3153 overflown |= r.1;
3154 }
3155 }
3156
3157 /// Raises self to the power of `exp`, using exponentiation by squaring.
3158 ///
3159 /// # Examples
3160 ///
3161 /// ```
3162 #[doc = concat!("let x: ", stringify!($SelfT), " = 2; // or any other integer type")]
3163 ///
3164 /// assert_eq!(x.pow(5), 32);
3165 #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".pow(0), 1);")]
3166 /// ```
3167 #[stable(feature = "rust1", since = "1.0.0")]
3168 #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")]
3169 #[must_use = "this returns the result of the operation, \
3170 without modifying the original"]
3171 #[inline]
3172 #[rustc_inherit_overflow_checks]
3173 pub const fn pow(self, mut exp: u32) -> Self {
3174 if exp == 0 {
3175 return 1;
3176 }
3177 let mut base = self;
3178 let mut acc = 1;
3179
3180 if intrinsics::is_val_statically_known(exp) {
3181 while exp > 1 {
3182 if (exp & 1) == 1 {
3183 acc = acc * base;
3184 }
3185 exp /= 2;
3186 base = base * base;
3187 }
3188
3189 // since exp!=0, finally the exp must be 1.
3190 // Deal with the final bit of the exponent separately, since
3191 // squaring the base afterwards is not necessary and may cause a
3192 // needless overflow.
3193 acc * base
3194 } else {
3195 // This is faster than the above when the exponent is not known
3196 // at compile time. We can't use the same code for the constant
3197 // exponent case because LLVM is currently unable to unroll
3198 // this loop.
3199 loop {
3200 if (exp & 1) == 1 {
3201 acc = acc * base;
3202 // since exp!=0, finally the exp must be 1.
3203 if exp == 1 {
3204 return acc;
3205 }
3206 }
3207 exp /= 2;
3208 base = base * base;
3209 }
3210 }
3211 }
3212
3213 /// Returns the integer square root of the number, rounded down.
3214 ///
3215 /// This function returns the **principal (non-negative) square root**.
3216 /// For a given number `n`, although both `x` and `-x` satisfy x<sup>2</sup> = n,
3217 /// this function always returns the non-negative value.
3218 ///
3219 /// # Panics
3220 ///
3221 /// This function will panic if `self` is negative.
3222 ///
3223 /// # Examples
3224 ///
3225 /// ```
3226 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")]
3227 /// ```
3228 #[stable(feature = "isqrt", since = "1.84.0")]
3229 #[rustc_const_stable(feature = "isqrt", since = "1.84.0")]
3230 #[must_use = "this returns the result of the operation, \
3231 without modifying the original"]
3232 #[inline]
3233 #[track_caller]
3234 pub const fn isqrt(self) -> Self {
3235 match self.checked_isqrt() {
3236 Some(sqrt) => sqrt,
3237 None => imp::int_sqrt::panic_for_negative_argument(),
3238 }
3239 }
3240
3241 /// Calculates the quotient of Euclidean division of `self` by `rhs`.
3242 ///
3243 /// This computes the integer `q` such that `self = q * rhs + r`, with
3244 /// `r = self.rem_euclid(rhs)` and `0 <= r < abs(rhs)`.
3245 ///
3246 /// In other words, the result is `self / rhs` rounded to the integer `q`
3247 /// such that `self >= q * rhs`.
3248 /// If `self > 0`, this is equal to rounding towards zero (the default in Rust);
3249 /// if `self < 0`, this is equal to rounding away from zero (towards +/- infinity).
3250 /// If `rhs > 0`, this is equal to rounding towards -infinity;
3251 /// if `rhs < 0`, this is equal to rounding towards +infinity.
3252 ///
3253 /// # Panics
3254 ///
3255 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3256 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3257 ///
3258 /// # Examples
3259 ///
3260 /// ```
3261 #[doc = concat!("let a: ", stringify!($SelfT), " = 7; // or any other integer type")]
3262 /// let b = 4;
3263 ///
3264 /// assert_eq!(a.div_euclid(b), 1); // 7 >= 4 * 1
3265 /// assert_eq!(a.div_euclid(-b), -1); // 7 >= -4 * -1
3266 /// assert_eq!((-a).div_euclid(b), -2); // -7 >= 4 * -2
3267 /// assert_eq!((-a).div_euclid(-b), 2); // -7 >= -4 * 2
3268 /// ```
3269 #[stable(feature = "euclidean_division", since = "1.38.0")]
3270 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3271 #[must_use = "this returns the result of the operation, \
3272 without modifying the original"]
3273 #[inline]
3274 #[track_caller]
3275 pub const fn div_euclid(self, rhs: Self) -> Self {
3276 let q = self / rhs;
3277 if self % rhs < 0 {
3278 return if rhs > 0 { q - 1 } else { q + 1 }
3279 }
3280 q
3281 }
3282
3283
3284 /// Calculates the least nonnegative remainder of `self` when
3285 /// divided by `rhs`.
3286 ///
3287 /// This is done as if by the Euclidean division algorithm -- given
3288 /// `r = self.rem_euclid(rhs)`, the result satisfies
3289 /// `self = rhs * self.div_euclid(rhs) + r` and `0 <= r < abs(rhs)`.
3290 ///
3291 /// # Panics
3292 ///
3293 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN` and
3294 /// `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3295 ///
3296 /// # Examples
3297 ///
3298 /// ```
3299 #[doc = concat!("let a: ", stringify!($SelfT), " = 7; // or any other integer type")]
3300 /// let b = 4;
3301 ///
3302 /// assert_eq!(a.rem_euclid(b), 3);
3303 /// assert_eq!((-a).rem_euclid(b), 1);
3304 /// assert_eq!(a.rem_euclid(-b), 3);
3305 /// assert_eq!((-a).rem_euclid(-b), 1);
3306 /// ```
3307 ///
3308 /// This will panic:
3309 /// ```should_panic
3310 #[doc = concat!("let _ = ", stringify!($SelfT), "::MIN.rem_euclid(-1);")]
3311 /// ```
3312 #[doc(alias = "modulo", alias = "mod")]
3313 #[stable(feature = "euclidean_division", since = "1.38.0")]
3314 #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")]
3315 #[must_use = "this returns the result of the operation, \
3316 without modifying the original"]
3317 #[inline]
3318 #[track_caller]
3319 pub const fn rem_euclid(self, rhs: Self) -> Self {
3320 let r = self % rhs;
3321 if r < 0 {
3322 // Semantically equivalent to `if rhs < 0 { r - rhs } else { r + rhs }`.
3323 // If `rhs` is not `Self::MIN`, then `r + abs(rhs)` will not overflow
3324 // and is clearly equivalent, because `r` is negative.
3325 // Otherwise, `rhs` is `Self::MIN`, then we have
3326 // `r.wrapping_add(Self::MIN.wrapping_abs())`, which evaluates
3327 // to `r.wrapping_add(Self::MIN)`, which is equivalent to
3328 // `r - Self::MIN`, which is what we wanted (and will not overflow
3329 // for negative `r`).
3330 r.wrapping_add(rhs.wrapping_abs())
3331 } else {
3332 r
3333 }
3334 }
3335
3336 /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity.
3337 ///
3338 /// # Panics
3339 ///
3340 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3341 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3342 ///
3343 /// # Examples
3344 ///
3345 /// ```
3346 /// #![feature(int_roundings)]
3347 #[doc = concat!("let a: ", stringify!($SelfT)," = 8;")]
3348 /// let b = 3;
3349 ///
3350 /// assert_eq!(a.div_floor(b), 2);
3351 /// assert_eq!(a.div_floor(-b), -3);
3352 /// assert_eq!((-a).div_floor(b), -3);
3353 /// assert_eq!((-a).div_floor(-b), 2);
3354 /// ```
3355 #[unstable(feature = "int_roundings", issue = "88581")]
3356 #[must_use = "this returns the result of the operation, \
3357 without modifying the original"]
3358 #[inline]
3359 #[track_caller]
3360 pub const fn div_floor(self, rhs: Self) -> Self {
3361 let d = self / rhs;
3362 let r = self % rhs;
3363
3364 // If the remainder is non-zero, we need to subtract one if the
3365 // signs of self and rhs differ, as this means we rounded upwards
3366 // instead of downwards. We do this branchlessly by creating a mask
3367 // which is all-ones iff the signs differ, and 0 otherwise. Then by
3368 // adding this mask (which corresponds to the signed value -1), we
3369 // get our correction.
3370 let correction = (self ^ rhs) >> (Self::BITS - 1);
3371 if r != 0 {
3372 d + correction
3373 } else {
3374 d
3375 }
3376 }
3377
3378 /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity.
3379 ///
3380 /// # Panics
3381 ///
3382 /// This function will panic if `rhs` is zero or if `self` is `Self::MIN`
3383 /// and `rhs` is -1. This behavior is not affected by the `overflow-checks` flag.
3384 ///
3385 /// # Examples
3386 ///
3387 /// ```
3388 /// #![feature(int_roundings)]
3389 #[doc = concat!("let a: ", stringify!($SelfT)," = 8;")]
3390 /// let b = 3;
3391 ///
3392 /// assert_eq!(a.div_ceil(b), 3);
3393 /// assert_eq!(a.div_ceil(-b), -2);
3394 /// assert_eq!((-a).div_ceil(b), -2);
3395 /// assert_eq!((-a).div_ceil(-b), 3);
3396 /// ```
3397 #[unstable(feature = "int_roundings", issue = "88581")]
3398 #[must_use = "this returns the result of the operation, \
3399 without modifying the original"]
3400 #[inline]
3401 #[track_caller]
3402 pub const fn div_ceil(self, rhs: Self) -> Self {
3403 let d = self / rhs;
3404 let r = self % rhs;
3405
3406 // When remainder is non-zero we have a.div_ceil(b) == 1 + a.div_floor(b),
3407 // so we can re-use the algorithm from div_floor, just adding 1.
3408 let correction = 1 + ((self ^ rhs) >> (Self::BITS - 1));
3409 if r != 0 {
3410 d + correction
3411 } else {
3412 d
3413 }
3414 }
3415
3416 /// If `rhs` is positive, calculates the smallest value greater than or
3417 /// equal to `self` that is a multiple of `rhs`. If `rhs` is negative,
3418 /// calculates the largest value less than or equal to `self` that is a
3419 /// multiple of `rhs`.
3420 ///
3421 /// # Panics
3422 ///
3423 /// This function will panic if `rhs` is zero.
3424 ///
3425 /// ## Overflow behavior
3426 ///
3427 /// On overflow, this function will panic if overflow checks are enabled (default in debug
3428 /// mode) and wrap if overflow checks are disabled (default in release mode).
3429 ///
3430 /// # Examples
3431 ///
3432 /// ```
3433 /// #![feature(int_roundings)]
3434 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")]
3435 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")]
3436 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(-8), 16);")]
3437 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(-8), 16);")]
3438 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").next_multiple_of(8), -16);")]
3439 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").next_multiple_of(8), -16);")]
3440 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").next_multiple_of(-8), -16);")]
3441 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").next_multiple_of(-8), -24);")]
3442 /// ```
3443 #[unstable(feature = "int_roundings", issue = "88581")]
3444 #[must_use = "this returns the result of the operation, \
3445 without modifying the original"]
3446 #[inline]
3447 #[rustc_inherit_overflow_checks]
3448 pub const fn next_multiple_of(self, rhs: Self) -> Self {
3449 // This would otherwise fail when calculating `r` when self == T::MIN.
3450 if rhs == -1 {
3451 return self;
3452 }
3453
3454 let r = self % rhs;
3455 let m = if (r > 0 && rhs < 0) || (r < 0 && rhs > 0) {
3456 r + rhs
3457 } else {
3458 r
3459 };
3460
3461 if m == 0 {
3462 self
3463 } else {
3464 self + (rhs - m)
3465 }
3466 }
3467
3468 /// If `rhs` is positive, calculates the smallest value greater than or
3469 /// equal to `self` that is a multiple of `rhs`. If `rhs` is negative,
3470 /// calculates the largest value less than or equal to `self` that is a
3471 /// multiple of `rhs`. Returns `None` if `rhs` is zero or the operation
3472 /// would result in overflow.
3473 ///
3474 /// # Examples
3475 ///
3476 /// ```
3477 /// #![feature(int_roundings)]
3478 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")]
3479 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")]
3480 #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(-8), Some(16));")]
3481 #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(-8), Some(16));")]
3482 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").checked_next_multiple_of(8), Some(-16));")]
3483 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").checked_next_multiple_of(8), Some(-16));")]
3484 #[doc = concat!("assert_eq!((-16_", stringify!($SelfT), ").checked_next_multiple_of(-8), Some(-16));")]
3485 #[doc = concat!("assert_eq!((-23_", stringify!($SelfT), ").checked_next_multiple_of(-8), Some(-24));")]
3486 #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")]
3487 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")]
3488 /// ```
3489 #[unstable(feature = "int_roundings", issue = "88581")]
3490 #[must_use = "this returns the result of the operation, \
3491 without modifying the original"]
3492 #[inline]
3493 pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> {
3494 // This would otherwise fail when calculating `r` when self == T::MIN.
3495 if rhs == -1 {
3496 return Some(self);
3497 }
3498
3499 let r = try_opt!(self.checked_rem(rhs));
3500 let m = if (r > 0 && rhs < 0) || (r < 0 && rhs > 0) {
3501 // r + rhs cannot overflow because they have opposite signs
3502 r + rhs
3503 } else {
3504 r
3505 };
3506
3507 if m == 0 {
3508 Some(self)
3509 } else {
3510 // rhs - m cannot overflow because m has the same sign as rhs
3511 self.checked_add(rhs - m)
3512 }
3513 }
3514
3515 /// Returns the logarithm of the number with respect to an arbitrary base,
3516 /// rounded down.
3517 ///
3518 /// This method might not be optimized owing to implementation details;
3519 /// `ilog2` can produce results more efficiently for base 2, and `ilog10`
3520 /// can produce results more efficiently for base 10.
3521 ///
3522 /// # Panics
3523 ///
3524 /// This function will panic if `self` is less than or equal to zero,
3525 /// or if `base` is less than 2.
3526 ///
3527 /// # Examples
3528 ///
3529 /// ```
3530 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")]
3531 /// ```
3532 #[stable(feature = "int_log", since = "1.67.0")]
3533 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3534 #[must_use = "this returns the result of the operation, \
3535 without modifying the original"]
3536 #[inline]
3537 #[track_caller]
3538 pub const fn ilog(self, base: Self) -> u32 {
3539 assert!(base >= 2, "base of integer logarithm must be at least 2");
3540 if let Some(log) = self.checked_ilog(base) {
3541 log
3542 } else {
3543 imp::int_log10::panic_for_nonpositive_argument()
3544 }
3545 }
3546
3547 /// Returns the base 2 logarithm of the number, rounded down.
3548 ///
3549 /// # Panics
3550 ///
3551 /// This function will panic if `self` is less than or equal to zero.
3552 ///
3553 /// # Examples
3554 ///
3555 /// ```
3556 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")]
3557 /// ```
3558 #[stable(feature = "int_log", since = "1.67.0")]
3559 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3560 #[must_use = "this returns the result of the operation, \
3561 without modifying the original"]
3562 #[inline]
3563 #[track_caller]
3564 pub const fn ilog2(self) -> u32 {
3565 if let Some(log) = self.checked_ilog2() {
3566 log
3567 } else {
3568 imp::int_log10::panic_for_nonpositive_argument()
3569 }
3570 }
3571
3572 /// Returns the base 10 logarithm of the number, rounded down.
3573 ///
3574 /// # Panics
3575 ///
3576 /// This function will panic if `self` is less than or equal to zero.
3577 ///
3578 /// # Example
3579 ///
3580 /// ```
3581 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")]
3582 /// ```
3583 #[stable(feature = "int_log", since = "1.67.0")]
3584 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3585 #[must_use = "this returns the result of the operation, \
3586 without modifying the original"]
3587 #[inline]
3588 #[track_caller]
3589 pub const fn ilog10(self) -> u32 {
3590 if let Some(log) = self.checked_ilog10() {
3591 log
3592 } else {
3593 imp::int_log10::panic_for_nonpositive_argument()
3594 }
3595 }
3596
3597 /// Returns the logarithm of the number with respect to an arbitrary base,
3598 /// rounded down.
3599 ///
3600 /// Returns `None` if the number is negative or zero, or if the base is not at least 2.
3601 ///
3602 /// This method might not be optimized owing to implementation details;
3603 /// `checked_ilog2` can produce results more efficiently for base 2, and
3604 /// `checked_ilog10` can produce results more efficiently for base 10.
3605 ///
3606 /// # Examples
3607 ///
3608 /// ```
3609 #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")]
3610 /// ```
3611 #[stable(feature = "int_log", since = "1.67.0")]
3612 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3613 #[must_use = "this returns the result of the operation, \
3614 without modifying the original"]
3615 #[inline]
3616 pub const fn checked_ilog(self, base: Self) -> Option<u32> {
3617 if self <= 0 || base <= 1 {
3618 None
3619 } else {
3620 // Delegate to the unsigned implementation.
3621 // The condition makes sure that both casts are exact.
3622 (self as $UnsignedT).checked_ilog(base as $UnsignedT)
3623 }
3624 }
3625
3626 /// Returns the base 2 logarithm of the number, rounded down.
3627 ///
3628 /// Returns `None` if the number is negative or zero.
3629 ///
3630 /// # Examples
3631 ///
3632 /// ```
3633 #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")]
3634 /// ```
3635 #[stable(feature = "int_log", since = "1.67.0")]
3636 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3637 #[must_use = "this returns the result of the operation, \
3638 without modifying the original"]
3639 #[inline]
3640 pub const fn checked_ilog2(self) -> Option<u32> {
3641 if self <= 0 {
3642 None
3643 } else {
3644 // SAFETY: We just checked that this number is positive
3645 let log = (Self::BITS - 1) - unsafe { intrinsics::ctlz_nonzero(self) as u32 };
3646 Some(log)
3647 }
3648 }
3649
3650 /// Returns the base 10 logarithm of the number, rounded down.
3651 ///
3652 /// Returns `None` if the number is negative or zero.
3653 ///
3654 /// # Example
3655 ///
3656 /// ```
3657 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")]
3658 /// ```
3659 #[stable(feature = "int_log", since = "1.67.0")]
3660 #[rustc_const_stable(feature = "int_log", since = "1.67.0")]
3661 #[must_use = "this returns the result of the operation, \
3662 without modifying the original"]
3663 #[inline]
3664 pub const fn checked_ilog10(self) -> Option<u32> {
3665 imp::int_log10::$ActualT(self as $ActualT)
3666 }
3667
3668 /// Computes the absolute value of `self`.
3669 ///
3670 /// # Overflow behavior
3671 ///
3672 /// The absolute value of
3673 #[doc = concat!("`", stringify!($SelfT), "::MIN`")]
3674 /// cannot be represented as an
3675 #[doc = concat!("`", stringify!($SelfT), "`,")]
3676 /// and attempting to calculate it will cause an overflow. This means
3677 /// that code in debug mode will trigger a panic on this case and
3678 /// optimized code will return
3679 #[doc = concat!("`", stringify!($SelfT), "::MIN`")]
3680 /// without a panic. If you do not want this behavior, consider
3681 /// using [`unsigned_abs`](Self::unsigned_abs) instead.
3682 ///
3683 /// # Examples
3684 ///
3685 /// ```
3686 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".abs(), 10);")]
3687 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").abs(), 10);")]
3688 /// ```
3689 #[stable(feature = "rust1", since = "1.0.0")]
3690 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3691 #[allow(unused_attributes)]
3692 #[must_use = "this returns the result of the operation, \
3693 without modifying the original"]
3694 #[inline]
3695 #[rustc_inherit_overflow_checks]
3696 pub const fn abs(self) -> Self {
3697 // Note that the #[rustc_inherit_overflow_checks] and #[inline]
3698 // above mean that the overflow semantics of the subtraction
3699 // depend on the crate we're being called from.
3700 if self.is_negative() {
3701 -self
3702 } else {
3703 self
3704 }
3705 }
3706
3707 /// Computes the absolute difference between `self` and `other`.
3708 ///
3709 /// This function always returns the correct answer without overflow or
3710 /// panics by returning an unsigned integer.
3711 ///
3712 /// # Examples
3713 ///
3714 /// ```
3715 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($UnsignedT), ");")]
3716 #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($UnsignedT), ");")]
3717 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").abs_diff(80), 180", stringify!($UnsignedT), ");")]
3718 #[doc = concat!("assert_eq!((-100", stringify!($SelfT), ").abs_diff(-120), 20", stringify!($UnsignedT), ");")]
3719 #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN.abs_diff(", stringify!($SelfT), "::MAX), ", stringify!($UnsignedT), "::MAX);")]
3720 /// ```
3721 #[stable(feature = "int_abs_diff", since = "1.60.0")]
3722 #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")]
3723 #[must_use = "this returns the result of the operation, \
3724 without modifying the original"]
3725 #[inline]
3726 pub const fn abs_diff(self, other: Self) -> $UnsignedT {
3727 if self < other {
3728 // Converting a non-negative x from signed to unsigned by using
3729 // `x as U` is left unchanged, but a negative x is converted
3730 // to value x + 2^N. Thus if `s` and `o` are binary variables
3731 // respectively indicating whether `self` and `other` are
3732 // negative, we are computing the mathematical value:
3733 //
3734 // (other + o*2^N) - (self + s*2^N) mod 2^N
3735 // other - self + (o-s)*2^N mod 2^N
3736 // other - self mod 2^N
3737 //
3738 // Finally, taking the mod 2^N of the mathematical value of
3739 // `other - self` does not change it as it already is
3740 // in the range [0, 2^N).
3741 (other as $UnsignedT).wrapping_sub(self as $UnsignedT)
3742 } else {
3743 (self as $UnsignedT).wrapping_sub(other as $UnsignedT)
3744 }
3745 }
3746
3747 /// Returns a number representing sign of `self`.
3748 ///
3749 /// - `0` if the number is zero
3750 /// - `1` if the number is positive
3751 /// - `-1` if the number is negative
3752 ///
3753 /// # Examples
3754 ///
3755 /// ```
3756 #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".signum(), 1);")]
3757 #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".signum(), 0);")]
3758 #[doc = concat!("assert_eq!((-10", stringify!($SelfT), ").signum(), -1);")]
3759 /// ```
3760 #[stable(feature = "rust1", since = "1.0.0")]
3761 #[rustc_const_stable(feature = "const_int_sign", since = "1.47.0")]
3762 #[must_use = "this returns the result of the operation, \
3763 without modifying the original"]
3764 #[inline(always)]
3765 pub const fn signum(self) -> Self {
3766 // Picking the right way to phrase this is complicated
3767 // (<https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>)
3768 // so delegate it to `Ord` which is already producing -1/0/+1
3769 // exactly like we need and can be the place to deal with the complexity.
3770
3771 crate::intrinsics::three_way_compare(self, 0) as Self
3772 }
3773
3774 /// Returns `true` if `self` is positive and `false` if the number is zero or
3775 /// negative.
3776 ///
3777 /// # Examples
3778 ///
3779 /// ```
3780 #[doc = concat!("assert!(10", stringify!($SelfT), ".is_positive());")]
3781 #[doc = concat!("assert!(!(-10", stringify!($SelfT), ").is_positive());")]
3782 /// ```
3783 #[must_use]
3784 #[stable(feature = "rust1", since = "1.0.0")]
3785 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3786 #[inline(always)]
3787 pub const fn is_positive(self) -> bool { self > 0 }
3788
3789 /// Returns `true` if `self` is negative and `false` if the number is zero or
3790 /// positive.
3791 ///
3792 /// # Examples
3793 ///
3794 /// ```
3795 #[doc = concat!("assert!((-10", stringify!($SelfT), ").is_negative());")]
3796 #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_negative());")]
3797 /// ```
3798 #[must_use]
3799 #[stable(feature = "rust1", since = "1.0.0")]
3800 #[rustc_const_stable(feature = "const_int_methods", since = "1.32.0")]
3801 #[inline(always)]
3802 pub const fn is_negative(self) -> bool { self < 0 }
3803
3804 /// Returns the memory representation of this integer as a byte array in
3805 /// big-endian (network) byte order.
3806 ///
3807 #[doc = $to_xe_bytes_doc]
3808 ///
3809 /// # Examples
3810 ///
3811 /// ```
3812 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")]
3813 #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")]
3814 /// ```
3815 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3816 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3817 #[must_use = "this returns the result of the operation, \
3818 without modifying the original"]
3819 #[inline]
3820 pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] {
3821 self.to_be().to_ne_bytes()
3822 }
3823
3824 /// Returns the memory representation of this integer as a byte array in
3825 /// little-endian byte order.
3826 ///
3827 #[doc = $to_xe_bytes_doc]
3828 ///
3829 /// # Examples
3830 ///
3831 /// ```
3832 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")]
3833 #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")]
3834 /// ```
3835 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3836 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3837 #[must_use = "this returns the result of the operation, \
3838 without modifying the original"]
3839 #[inline]
3840 pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] {
3841 self.to_le().to_ne_bytes()
3842 }
3843
3844 /// Returns the memory representation of this integer as a byte array in
3845 /// native byte order.
3846 ///
3847 /// As the target platform's native endianness is used, portable code
3848 /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate,
3849 /// instead.
3850 ///
3851 #[doc = $to_xe_bytes_doc]
3852 ///
3853 /// [`to_be_bytes`]: Self::to_be_bytes
3854 /// [`to_le_bytes`]: Self::to_le_bytes
3855 ///
3856 /// # Examples
3857 ///
3858 /// ```
3859 #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")]
3860 /// assert_eq!(
3861 /// bytes,
3862 /// if cfg!(target_endian = "big") {
3863 #[doc = concat!(" ", $be_bytes)]
3864 /// } else {
3865 #[doc = concat!(" ", $le_bytes)]
3866 /// }
3867 /// );
3868 /// ```
3869 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3870 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3871 #[allow(unnecessary_transmutes)]
3872 // SAFETY: const sound because integers are plain old datatypes so we can always
3873 // transmute them to arrays of bytes
3874 #[must_use = "this returns the result of the operation, \
3875 without modifying the original"]
3876 #[inline]
3877 pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] {
3878 // SAFETY: integers are plain old datatypes so we can always transmute them to
3879 // arrays of bytes
3880 unsafe { mem::transmute(self) }
3881 }
3882
3883 /// Creates an integer value from its representation as a byte array in
3884 /// big endian.
3885 ///
3886 #[doc = $from_xe_bytes_doc]
3887 ///
3888 /// # Examples
3889 ///
3890 /// ```
3891 #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")]
3892 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3893 /// ```
3894 ///
3895 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3896 ///
3897 /// ```
3898 #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3899 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3900 /// *input = rest;
3901 #[doc = concat!(" ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")]
3902 /// }
3903 /// ```
3904 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3905 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3906 #[must_use]
3907 #[inline]
3908 pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3909 Self::from_be(Self::from_ne_bytes(bytes))
3910 }
3911
3912 /// Creates an integer value from its representation as a byte array in
3913 /// little endian.
3914 ///
3915 #[doc = $from_xe_bytes_doc]
3916 ///
3917 /// # Examples
3918 ///
3919 /// ```
3920 #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")]
3921 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3922 /// ```
3923 ///
3924 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3925 ///
3926 /// ```
3927 #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3928 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3929 /// *input = rest;
3930 #[doc = concat!(" ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")]
3931 /// }
3932 /// ```
3933 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3934 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3935 #[must_use]
3936 #[inline]
3937 pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3938 Self::from_le(Self::from_ne_bytes(bytes))
3939 }
3940
3941 /// Creates an integer value from its memory representation as a byte
3942 /// array in native endianness.
3943 ///
3944 /// As the target platform's native endianness is used, portable code
3945 /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as
3946 /// appropriate instead.
3947 ///
3948 /// [`from_be_bytes`]: Self::from_be_bytes
3949 /// [`from_le_bytes`]: Self::from_le_bytes
3950 ///
3951 #[doc = $from_xe_bytes_doc]
3952 ///
3953 /// # Examples
3954 ///
3955 /// ```
3956 #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian = \"big\") {")]
3957 #[doc = concat!(" ", $be_bytes)]
3958 /// } else {
3959 #[doc = concat!(" ", $le_bytes)]
3960 /// });
3961 #[doc = concat!("assert_eq!(value, ", $swap_op, ");")]
3962 /// ```
3963 ///
3964 /// When starting from a slice rather than an array, fallible conversion APIs can be used:
3965 ///
3966 /// ```
3967 #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")]
3968 #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")]
3969 /// *input = rest;
3970 #[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")]
3971 /// }
3972 /// ```
3973 #[stable(feature = "int_to_from_bytes", since = "1.32.0")]
3974 #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")]
3975 #[allow(unnecessary_transmutes)]
3976 #[must_use]
3977 // SAFETY: const sound because integers are plain old datatypes so we can always
3978 // transmute to them
3979 #[inline]
3980 pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self {
3981 // SAFETY: integers are plain old datatypes so we can always transmute to them
3982 unsafe { mem::transmute(bytes) }
3983 }
3984
3985 /// New code should prefer to use
3986 #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")]
3987 ///
3988 /// Returns the smallest value that can be represented by this integer type.
3989 #[stable(feature = "rust1", since = "1.0.0")]
3990 #[inline(always)]
3991 #[rustc_promotable]
3992 #[rustc_const_stable(feature = "const_min_value", since = "1.32.0")]
3993 #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")]
3994 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")]
3995 pub const fn min_value() -> Self {
3996 Self::MIN
3997 }
3998
3999 /// New code should prefer to use
4000 #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")]
4001 ///
4002 /// Returns the largest value that can be represented by this integer type.
4003 #[stable(feature = "rust1", since = "1.0.0")]
4004 #[inline(always)]
4005 #[rustc_promotable]
4006 #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")]
4007 #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")]
4008 #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")]
4009 pub const fn max_value() -> Self {
4010 Self::MAX
4011 }
4012
4013 /// Clamps this number to a symmetric range centred around zero.
4014 ///
4015 /// The method clamps the number's magnitude (absolute value) to be at most `limit`.
4016 ///
4017 /// This is functionally equivalent to `self.clamp(-limit, limit)`, but is more
4018 /// explicit about the intent.
4019 ///
4020 /// # Examples
4021 ///
4022 /// ```
4023 /// #![feature(clamp_magnitude)]
4024 #[doc = concat!("assert_eq!(120", stringify!($SelfT), ".clamp_magnitude(100), 100);")]
4025 #[doc = concat!("assert_eq!(-120", stringify!($SelfT), ".clamp_magnitude(100), -100);")]
4026 #[doc = concat!("assert_eq!(80", stringify!($SelfT), ".clamp_magnitude(100), 80);")]
4027 #[doc = concat!("assert_eq!(-80", stringify!($SelfT), ".clamp_magnitude(100), -80);")]
4028 /// ```
4029 #[must_use = "this returns the clamped value and does not modify the original"]
4030 #[unstable(feature = "clamp_magnitude", issue = "148519")]
4031 #[inline]
4032 pub fn clamp_magnitude(self, limit: $UnsignedT) -> Self {
4033 if let Ok(limit) = core::convert::TryInto::<$SelfT>::try_into(limit) {
4034 self.clamp(-limit, limit)
4035 } else {
4036 self
4037 }
4038 }
4039
4040 /// Truncate an integer to an integer of the same size or smaller, preserving the least
4041 /// significant bits.
4042 ///
4043 /// # Examples
4044 ///
4045 /// ```
4046 /// #![feature(integer_extend_truncate)]
4047 #[doc = concat!("assert_eq!(120i8, 120", stringify!($SelfT), ".truncate());")]
4048 #[doc = concat!("assert_eq!(-120i8, (-120", stringify!($SelfT), ").truncate());")]
4049 /// assert_eq!(120i8, 376i32.truncate());
4050 /// ```
4051 #[must_use = "this returns the truncated value and does not modify the original"]
4052 #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4053 #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4054 #[inline]
4055 pub const fn truncate<Target>(self) -> Target
4056 where Self: [const] traits::TruncateTarget<Target>
4057 {
4058 traits::TruncateTarget::internal_truncate(self)
4059 }
4060
4061 /// Truncate an integer to an integer of the same size or smaller, saturating at numeric bounds
4062 /// instead of truncating.
4063 ///
4064 /// # Examples
4065 ///
4066 /// ```
4067 /// #![feature(integer_extend_truncate)]
4068 #[doc = concat!("assert_eq!(120i8, 120", stringify!($SelfT), ".saturating_truncate());")]
4069 #[doc = concat!("assert_eq!(-120i8, (-120", stringify!($SelfT), ").saturating_truncate());")]
4070 /// assert_eq!(127i8, 376i32.saturating_truncate());
4071 /// assert_eq!(-128i8, (-1000i32).saturating_truncate());
4072 /// ```
4073 #[must_use = "this returns the truncated value and does not modify the original"]
4074 #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4075 #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4076 #[inline]
4077 pub const fn saturating_truncate<Target>(self) -> Target
4078 where Self: [const] traits::TruncateTarget<Target>
4079 {
4080 traits::TruncateTarget::internal_saturating_truncate(self)
4081 }
4082
4083 /// Truncate an integer to an integer of the same size or smaller, returning `None` if the value
4084 /// is outside the bounds of the smaller type.
4085 ///
4086 /// # Examples
4087 ///
4088 /// ```
4089 /// #![feature(integer_extend_truncate)]
4090 #[doc = concat!("assert_eq!(Some(120i8), 120", stringify!($SelfT), ".checked_truncate());")]
4091 #[doc = concat!("assert_eq!(Some(-120i8), (-120", stringify!($SelfT), ").checked_truncate());")]
4092 /// assert_eq!(None, 376i32.checked_truncate::<i8>());
4093 /// assert_eq!(None, (-1000i32).checked_truncate::<i8>());
4094 /// ```
4095 #[must_use = "this returns the truncated value and does not modify the original"]
4096 #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4097 #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4098 #[inline]
4099 pub const fn checked_truncate<Target>(self) -> Option<Target>
4100 where Self: [const] traits::TruncateTarget<Target>
4101 {
4102 traits::TruncateTarget::internal_checked_truncate(self)
4103 }
4104
4105 /// Extend to an integer of the same size or larger, preserving its value.
4106 ///
4107 /// # Examples
4108 ///
4109 /// ```
4110 /// #![feature(integer_extend_truncate)]
4111 #[doc = concat!("assert_eq!(120i128, 120i8.extend());")]
4112 #[doc = concat!("assert_eq!(-120i128, (-120i8).extend());")]
4113 /// ```
4114 #[must_use = "this returns the extended value and does not modify the original"]
4115 #[unstable(feature = "integer_extend_truncate", issue = "154330")]
4116 #[rustc_const_unstable(feature = "integer_extend_truncate", issue = "154330")]
4117 #[inline]
4118 pub const fn extend<Target>(self) -> Target
4119 where Self: [const] traits::ExtendTarget<Target>
4120 {
4121 traits::ExtendTarget::internal_extend(self)
4122 }
4123 }
4124}