1 | macro_rules! uint_impl { |
---|---|
2 | ( |
3 | Self = $SelfT:ty, |
4 | ActualT = $ActualT:ident, |
5 | SignedT = $SignedT:ident, |
6 | |
7 | // These are all for use *only* in doc comments. |
8 | // As such, they're all passed as literals -- passing them as a string |
9 | // literal is fine if they need to be multiple code tokens. |
10 | // In non-comments, use the associated constants rather than these. |
11 | BITS = $BITS:literal, |
12 | BITS_MINUS_ONE = $BITS_MINUS_ONE:literal, |
13 | MAX = $MaxV:literal, |
14 | rot = $rot:literal, |
15 | rot_op = $rot_op:literal, |
16 | rot_result = $rot_result:literal, |
17 | swap_op = $swap_op:literal, |
18 | swapped = $swapped:literal, |
19 | reversed = $reversed:literal, |
20 | le_bytes = $le_bytes:literal, |
21 | be_bytes = $be_bytes:literal, |
22 | to_xe_bytes_doc = $to_xe_bytes_doc:expr, |
23 | from_xe_bytes_doc = $from_xe_bytes_doc:expr, |
24 | bound_condition = $bound_condition:literal, |
25 | ) => { |
26 | /// The smallest value that can be represented by this integer type. |
27 | /// |
28 | /// # Examples |
29 | /// |
30 | /// Basic usage: |
31 | /// |
32 | /// ``` |
33 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MIN, 0);")] |
34 | /// ``` |
35 | #[stable(feature = "assoc_int_consts", since = "1.43.0")] |
36 | pub const MIN: Self = 0; |
37 | |
38 | /// The largest value that can be represented by this integer type |
39 | #[doc = concat!("(2<sup>", $BITS, "</sup> − 1", $bound_condition, ").")] |
40 | /// |
41 | /// # Examples |
42 | /// |
43 | /// Basic usage: |
44 | /// |
45 | /// ``` |
46 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX, ", stringify!($MaxV), ");")] |
47 | /// ``` |
48 | #[stable(feature = "assoc_int_consts", since = "1.43.0")] |
49 | pub const MAX: Self = !0; |
50 | |
51 | /// The size of this integer type in bits. |
52 | /// |
53 | /// # Examples |
54 | /// |
55 | /// ``` |
56 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::BITS, ", stringify!($BITS), ");")] |
57 | /// ``` |
58 | #[stable(feature = "int_bits_const", since = "1.53.0")] |
59 | pub const BITS: u32 = Self::MAX.count_ones(); |
60 | |
61 | /// Returns the number of ones in the binary representation of `self`. |
62 | /// |
63 | /// # Examples |
64 | /// |
65 | /// Basic usage: |
66 | /// |
67 | /// ``` |
68 | #[doc = concat!("let n = 0b01001100", stringify!($SelfT), ";")] |
69 | /// assert_eq!(n.count_ones(), 3); |
70 | /// |
71 | #[doc = concat!("let max = ", stringify!($SelfT), "::MAX;")] |
72 | #[doc = concat!("assert_eq!(max.count_ones(), ", stringify!($BITS), ");")] |
73 | /// |
74 | #[doc = concat!("let zero = 0", stringify!($SelfT), ";")] |
75 | /// assert_eq!(zero.count_ones(), 0); |
76 | /// ``` |
77 | #[stable(feature = "rust1", since = "1.0.0")] |
78 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
79 | #[doc(alias = "popcount")] |
80 | #[doc(alias = "popcnt")] |
81 | #[must_use = "this returns the result of the operation, \ |
82 | without modifying the original"] |
83 | #[inline(always)] |
84 | pub const fn count_ones(self) -> u32 { |
85 | return intrinsics::ctpop(self); |
86 | } |
87 | |
88 | /// Returns the number of zeros in the binary representation of `self`. |
89 | /// |
90 | /// # Examples |
91 | /// |
92 | /// Basic usage: |
93 | /// |
94 | /// ``` |
95 | #[doc = concat!("let zero = 0", stringify!($SelfT), ";")] |
96 | #[doc = concat!("assert_eq!(zero.count_zeros(), ", stringify!($BITS), ");")] |
97 | /// |
98 | #[doc = concat!("let max = ", stringify!($SelfT), "::MAX;")] |
99 | /// assert_eq!(max.count_zeros(), 0); |
100 | /// ``` |
101 | #[stable(feature = "rust1", since = "1.0.0")] |
102 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
103 | #[must_use = "this returns the result of the operation, \ |
104 | without modifying the original"] |
105 | #[inline(always)] |
106 | pub const fn count_zeros(self) -> u32 { |
107 | (!self).count_ones() |
108 | } |
109 | |
110 | /// Returns the number of leading zeros in the binary representation of `self`. |
111 | /// |
112 | /// Depending on what you're doing with the value, you might also be interested in the |
113 | /// [`ilog2`] function which returns a consistent number, even if the type widens. |
114 | /// |
115 | /// # Examples |
116 | /// |
117 | /// Basic usage: |
118 | /// |
119 | /// ``` |
120 | #[doc = concat!("let n = ", stringify!($SelfT), "::MAX >> 2;")] |
121 | /// assert_eq!(n.leading_zeros(), 2); |
122 | /// |
123 | #[doc = concat!("let zero = 0", stringify!($SelfT), ";")] |
124 | #[doc = concat!("assert_eq!(zero.leading_zeros(), ", stringify!($BITS), ");")] |
125 | /// |
126 | #[doc = concat!("let max = ", stringify!($SelfT), "::MAX;")] |
127 | /// assert_eq!(max.leading_zeros(), 0); |
128 | /// ``` |
129 | #[doc = concat!("[`ilog2`]: ", stringify!($SelfT), "::ilog2")] |
130 | #[stable(feature = "rust1", since = "1.0.0")] |
131 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
132 | #[must_use = "this returns the result of the operation, \ |
133 | without modifying the original"] |
134 | #[inline(always)] |
135 | pub const fn leading_zeros(self) -> u32 { |
136 | return intrinsics::ctlz(self as $ActualT); |
137 | } |
138 | |
139 | /// Returns the number of trailing zeros in the binary representation |
140 | /// of `self`. |
141 | /// |
142 | /// # Examples |
143 | /// |
144 | /// Basic usage: |
145 | /// |
146 | /// ``` |
147 | #[doc = concat!("let n = 0b0101000", stringify!($SelfT), ";")] |
148 | /// assert_eq!(n.trailing_zeros(), 3); |
149 | /// |
150 | #[doc = concat!("let zero = 0", stringify!($SelfT), ";")] |
151 | #[doc = concat!("assert_eq!(zero.trailing_zeros(), ", stringify!($BITS), ");")] |
152 | /// |
153 | #[doc = concat!("let max = ", stringify!($SelfT), "::MAX;")] |
154 | #[doc = concat!("assert_eq!(max.trailing_zeros(), 0);")] |
155 | /// ``` |
156 | #[stable(feature = "rust1", since = "1.0.0")] |
157 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
158 | #[must_use = "this returns the result of the operation, \ |
159 | without modifying the original"] |
160 | #[inline(always)] |
161 | pub const fn trailing_zeros(self) -> u32 { |
162 | return intrinsics::cttz(self); |
163 | } |
164 | |
165 | /// Returns the number of leading ones in the binary representation of `self`. |
166 | /// |
167 | /// # Examples |
168 | /// |
169 | /// Basic usage: |
170 | /// |
171 | /// ``` |
172 | #[doc = concat!("let n = !(", stringify!($SelfT), "::MAX >> 2);")] |
173 | /// assert_eq!(n.leading_ones(), 2); |
174 | /// |
175 | #[doc = concat!("let zero = 0", stringify!($SelfT), ";")] |
176 | /// assert_eq!(zero.leading_ones(), 0); |
177 | /// |
178 | #[doc = concat!("let max = ", stringify!($SelfT), "::MAX;")] |
179 | #[doc = concat!("assert_eq!(max.leading_ones(), ", stringify!($BITS), ");")] |
180 | /// ``` |
181 | #[stable(feature = "leading_trailing_ones", since = "1.46.0")] |
182 | #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")] |
183 | #[must_use = "this returns the result of the operation, \ |
184 | without modifying the original"] |
185 | #[inline(always)] |
186 | pub const fn leading_ones(self) -> u32 { |
187 | (!self).leading_zeros() |
188 | } |
189 | |
190 | /// Returns the number of trailing ones in the binary representation |
191 | /// of `self`. |
192 | /// |
193 | /// # Examples |
194 | /// |
195 | /// Basic usage: |
196 | /// |
197 | /// ``` |
198 | #[doc = concat!("let n = 0b1010111", stringify!($SelfT), ";")] |
199 | /// assert_eq!(n.trailing_ones(), 3); |
200 | /// |
201 | #[doc = concat!("let zero = 0", stringify!($SelfT), ";")] |
202 | /// assert_eq!(zero.trailing_ones(), 0); |
203 | /// |
204 | #[doc = concat!("let max = ", stringify!($SelfT), "::MAX;")] |
205 | #[doc = concat!("assert_eq!(max.trailing_ones(), ", stringify!($BITS), ");")] |
206 | /// ``` |
207 | #[stable(feature = "leading_trailing_ones", since = "1.46.0")] |
208 | #[rustc_const_stable(feature = "leading_trailing_ones", since = "1.46.0")] |
209 | #[must_use = "this returns the result of the operation, \ |
210 | without modifying the original"] |
211 | #[inline(always)] |
212 | pub const fn trailing_ones(self) -> u32 { |
213 | (!self).trailing_zeros() |
214 | } |
215 | |
216 | /// Returns the minimum number of bits required to represent `self`. |
217 | /// |
218 | /// This method returns zero if `self` is zero. |
219 | /// |
220 | /// # Examples |
221 | /// |
222 | /// Basic usage: |
223 | /// |
224 | /// ``` |
225 | /// #![feature(uint_bit_width)] |
226 | /// |
227 | #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".bit_width(), 0);")] |
228 | #[doc = concat!("assert_eq!(0b111_", stringify!($SelfT), ".bit_width(), 3);")] |
229 | #[doc = concat!("assert_eq!(0b1110_", stringify!($SelfT), ".bit_width(), 4);")] |
230 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.bit_width(), ", stringify!($BITS), ");")] |
231 | /// ``` |
232 | #[unstable(feature = "uint_bit_width", issue = "142326")] |
233 | #[must_use = "this returns the result of the operation, \ |
234 | without modifying the original"] |
235 | #[inline(always)] |
236 | pub const fn bit_width(self) -> u32 { |
237 | Self::BITS - self.leading_zeros() |
238 | } |
239 | |
240 | /// Returns `self` with only the most significant bit set, or `0` if |
241 | /// the input is `0`. |
242 | /// |
243 | /// # Examples |
244 | /// |
245 | /// Basic usage: |
246 | /// |
247 | /// ``` |
248 | /// #![feature(isolate_most_least_significant_one)] |
249 | /// |
250 | #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")] |
251 | /// |
252 | /// assert_eq!(n.isolate_most_significant_one(), 0b_01000000); |
253 | #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_most_significant_one(), 0);")] |
254 | /// ``` |
255 | #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")] |
256 | #[must_use = "this returns the result of the operation, \ |
257 | without modifying the original"] |
258 | #[inline(always)] |
259 | pub const fn isolate_most_significant_one(self) -> Self { |
260 | self & (((1 as $SelfT) << (<$SelfT>::BITS - 1)).wrapping_shr(self.leading_zeros())) |
261 | } |
262 | |
263 | /// Returns `self` with only the least significant bit set, or `0` if |
264 | /// the input is `0`. |
265 | /// |
266 | /// # Examples |
267 | /// |
268 | /// Basic usage: |
269 | /// |
270 | /// ``` |
271 | /// #![feature(isolate_most_least_significant_one)] |
272 | /// |
273 | #[doc = concat!("let n: ", stringify!($SelfT), " = 0b_01100100;")] |
274 | /// |
275 | /// assert_eq!(n.isolate_least_significant_one(), 0b_00000100); |
276 | #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".isolate_least_significant_one(), 0);")] |
277 | /// ``` |
278 | #[unstable(feature = "isolate_most_least_significant_one", issue = "136909")] |
279 | #[must_use = "this returns the result of the operation, \ |
280 | without modifying the original"] |
281 | #[inline(always)] |
282 | pub const fn isolate_least_significant_one(self) -> Self { |
283 | self & self.wrapping_neg() |
284 | } |
285 | |
286 | /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size. |
287 | /// |
288 | /// This produces the same result as an `as` cast, but ensures that the bit-width remains |
289 | /// the same. |
290 | /// |
291 | /// # Examples |
292 | /// |
293 | /// Basic usage: |
294 | /// |
295 | /// ``` |
296 | #[doc = concat!("let n = ", stringify!($SelfT), "::MAX;")] |
297 | /// |
298 | #[doc = concat!("assert_eq!(n.cast_signed(), -1", stringify!($SignedT), ");")] |
299 | /// ``` |
300 | #[stable(feature = "integer_sign_cast", since = "1.87.0")] |
301 | #[rustc_const_stable(feature = "integer_sign_cast", since = "1.87.0")] |
302 | #[must_use = "this returns the result of the operation, \ |
303 | without modifying the original"] |
304 | #[inline(always)] |
305 | pub const fn cast_signed(self) -> $SignedT { |
306 | self as $SignedT |
307 | } |
308 | |
309 | /// Shifts the bits to the left by a specified amount, `n`, |
310 | /// wrapping the truncated bits to the end of the resulting integer. |
311 | /// |
312 | /// Please note this isn't the same operation as the `<<` shifting operator! |
313 | /// |
314 | /// # Examples |
315 | /// |
316 | /// Basic usage: |
317 | /// |
318 | /// ``` |
319 | #[doc = concat!("let n = ", $rot_op, stringify!($SelfT), ";")] |
320 | #[doc = concat!("let m = ", $rot_result, ";")] |
321 | /// |
322 | #[doc = concat!("assert_eq!(n.rotate_left(", $rot, "), m);")] |
323 | /// ``` |
324 | #[stable(feature = "rust1", since = "1.0.0")] |
325 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
326 | #[must_use = "this returns the result of the operation, \ |
327 | without modifying the original"] |
328 | #[inline(always)] |
329 | pub const fn rotate_left(self, n: u32) -> Self { |
330 | return intrinsics::rotate_left(self, n); |
331 | } |
332 | |
333 | /// Shifts the bits to the right by a specified amount, `n`, |
334 | /// wrapping the truncated bits to the beginning of the resulting |
335 | /// integer. |
336 | /// |
337 | /// Please note this isn't the same operation as the `>>` shifting operator! |
338 | /// |
339 | /// # Examples |
340 | /// |
341 | /// Basic usage: |
342 | /// |
343 | /// ``` |
344 | #[doc = concat!("let n = ", $rot_result, stringify!($SelfT), ";")] |
345 | #[doc = concat!("let m = ", $rot_op, ";")] |
346 | /// |
347 | #[doc = concat!("assert_eq!(n.rotate_right(", $rot, "), m);")] |
348 | /// ``` |
349 | #[stable(feature = "rust1", since = "1.0.0")] |
350 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
351 | #[must_use = "this returns the result of the operation, \ |
352 | without modifying the original"] |
353 | #[inline(always)] |
354 | pub const fn rotate_right(self, n: u32) -> Self { |
355 | return intrinsics::rotate_right(self, n); |
356 | } |
357 | |
358 | /// Reverses the byte order of the integer. |
359 | /// |
360 | /// # Examples |
361 | /// |
362 | /// Basic usage: |
363 | /// |
364 | /// ``` |
365 | #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")] |
366 | /// let m = n.swap_bytes(); |
367 | /// |
368 | #[doc = concat!("assert_eq!(m, ", $swapped, ");")] |
369 | /// ``` |
370 | #[stable(feature = "rust1", since = "1.0.0")] |
371 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
372 | #[must_use = "this returns the result of the operation, \ |
373 | without modifying the original"] |
374 | #[inline(always)] |
375 | pub const fn swap_bytes(self) -> Self { |
376 | intrinsics::bswap(self as $ActualT) as Self |
377 | } |
378 | |
379 | /// Reverses the order of bits in the integer. The least significant bit becomes the most significant bit, |
380 | /// second least-significant bit becomes second most-significant bit, etc. |
381 | /// |
382 | /// # Examples |
383 | /// |
384 | /// Basic usage: |
385 | /// |
386 | /// ``` |
387 | #[doc = concat!("let n = ", $swap_op, stringify!($SelfT), ";")] |
388 | /// let m = n.reverse_bits(); |
389 | /// |
390 | #[doc = concat!("assert_eq!(m, ", $reversed, ");")] |
391 | #[doc = concat!("assert_eq!(0, 0", stringify!($SelfT), ".reverse_bits());")] |
392 | /// ``` |
393 | #[stable(feature = "reverse_bits", since = "1.37.0")] |
394 | #[rustc_const_stable(feature = "reverse_bits", since = "1.37.0")] |
395 | #[must_use = "this returns the result of the operation, \ |
396 | without modifying the original"] |
397 | #[inline(always)] |
398 | pub const fn reverse_bits(self) -> Self { |
399 | intrinsics::bitreverse(self as $ActualT) as Self |
400 | } |
401 | |
402 | /// Converts an integer from big endian to the target's endianness. |
403 | /// |
404 | /// On big endian this is a no-op. On little endian the bytes are |
405 | /// swapped. |
406 | /// |
407 | /// # Examples |
408 | /// |
409 | /// Basic usage: |
410 | /// |
411 | /// ``` |
412 | #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")] |
413 | /// |
414 | /// if cfg!(target_endian = "big") { |
415 | #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n)")] |
416 | /// } else { |
417 | #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_be(n), n.swap_bytes())")] |
418 | /// } |
419 | /// ``` |
420 | #[stable(feature = "rust1", since = "1.0.0")] |
421 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
422 | #[must_use] |
423 | #[inline(always)] |
424 | pub const fn from_be(x: Self) -> Self { |
425 | #[cfg(target_endian = "big")] |
426 | { |
427 | x |
428 | } |
429 | #[cfg(not(target_endian = "big"))] |
430 | { |
431 | x.swap_bytes() |
432 | } |
433 | } |
434 | |
435 | /// Converts an integer from little endian to the target's endianness. |
436 | /// |
437 | /// On little endian this is a no-op. On big endian the bytes are |
438 | /// swapped. |
439 | /// |
440 | /// # Examples |
441 | /// |
442 | /// Basic usage: |
443 | /// |
444 | /// ``` |
445 | #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")] |
446 | /// |
447 | /// if cfg!(target_endian = "little") { |
448 | #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n)")] |
449 | /// } else { |
450 | #[doc = concat!(" assert_eq!(", stringify!($SelfT), "::from_le(n), n.swap_bytes())")] |
451 | /// } |
452 | /// ``` |
453 | #[stable(feature = "rust1", since = "1.0.0")] |
454 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
455 | #[must_use] |
456 | #[inline(always)] |
457 | pub const fn from_le(x: Self) -> Self { |
458 | #[cfg(target_endian = "little")] |
459 | { |
460 | x |
461 | } |
462 | #[cfg(not(target_endian = "little"))] |
463 | { |
464 | x.swap_bytes() |
465 | } |
466 | } |
467 | |
468 | /// Converts `self` to big endian from the target's endianness. |
469 | /// |
470 | /// On big endian this is a no-op. On little endian the bytes are |
471 | /// swapped. |
472 | /// |
473 | /// # Examples |
474 | /// |
475 | /// Basic usage: |
476 | /// |
477 | /// ``` |
478 | #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")] |
479 | /// |
480 | /// if cfg!(target_endian = "big") { |
481 | /// assert_eq!(n.to_be(), n) |
482 | /// } else { |
483 | /// assert_eq!(n.to_be(), n.swap_bytes()) |
484 | /// } |
485 | /// ``` |
486 | #[stable(feature = "rust1", since = "1.0.0")] |
487 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
488 | #[must_use = "this returns the result of the operation, \ |
489 | without modifying the original"] |
490 | #[inline(always)] |
491 | pub const fn to_be(self) -> Self { // or not to be? |
492 | #[cfg(target_endian = "big")] |
493 | { |
494 | self |
495 | } |
496 | #[cfg(not(target_endian = "big"))] |
497 | { |
498 | self.swap_bytes() |
499 | } |
500 | } |
501 | |
502 | /// Converts `self` to little endian from the target's endianness. |
503 | /// |
504 | /// On little endian this is a no-op. On big endian the bytes are |
505 | /// swapped. |
506 | /// |
507 | /// # Examples |
508 | /// |
509 | /// Basic usage: |
510 | /// |
511 | /// ``` |
512 | #[doc = concat!("let n = 0x1A", stringify!($SelfT), ";")] |
513 | /// |
514 | /// if cfg!(target_endian = "little") { |
515 | /// assert_eq!(n.to_le(), n) |
516 | /// } else { |
517 | /// assert_eq!(n.to_le(), n.swap_bytes()) |
518 | /// } |
519 | /// ``` |
520 | #[stable(feature = "rust1", since = "1.0.0")] |
521 | #[rustc_const_stable(feature = "const_math", since = "1.32.0")] |
522 | #[must_use = "this returns the result of the operation, \ |
523 | without modifying the original"] |
524 | #[inline(always)] |
525 | pub const fn to_le(self) -> Self { |
526 | #[cfg(target_endian = "little")] |
527 | { |
528 | self |
529 | } |
530 | #[cfg(not(target_endian = "little"))] |
531 | { |
532 | self.swap_bytes() |
533 | } |
534 | } |
535 | |
536 | /// Checked integer addition. Computes `self + rhs`, returning `None` |
537 | /// if overflow occurred. |
538 | /// |
539 | /// # Examples |
540 | /// |
541 | /// Basic usage: |
542 | /// |
543 | /// ``` |
544 | #[doc = concat!( |
545 | "assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(1), ", |
546 | "Some(", stringify!($SelfT), "::MAX - 1));" |
547 | )] |
548 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);")] |
549 | /// ``` |
550 | #[stable(feature = "rust1", since = "1.0.0")] |
551 | #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] |
552 | #[must_use = "this returns the result of the operation, \ |
553 | without modifying the original"] |
554 | #[inline] |
555 | pub const fn checked_add(self, rhs: Self) -> Option<Self> { |
556 | // This used to use `overflowing_add`, but that means it ends up being |
557 | // a `wrapping_add`, losing some optimization opportunities. Notably, |
558 | // phrasing it this way helps `.checked_add(1)` optimize to a check |
559 | // against `MAX` and a `add nuw`. |
560 | // Per <https://github.com/rust-lang/rust/pull/124114#issuecomment-2066173305>, |
561 | // LLVM is happy to re-form the intrinsic later if useful. |
562 | |
563 | if intrinsics::unlikely(intrinsics::add_with_overflow(self, rhs).1) { |
564 | None |
565 | } else { |
566 | // SAFETY: Just checked it doesn't overflow |
567 | Some(unsafe { intrinsics::unchecked_add(self, rhs) }) |
568 | } |
569 | } |
570 | |
571 | /// Strict integer addition. Computes `self + rhs`, panicking |
572 | /// if overflow occurred. |
573 | /// |
574 | /// # Panics |
575 | /// |
576 | /// ## Overflow behavior |
577 | /// |
578 | /// This function will always panic on overflow, regardless of whether overflow checks are enabled. |
579 | /// |
580 | /// # Examples |
581 | /// |
582 | /// Basic usage: |
583 | /// |
584 | /// ``` |
585 | /// #![feature(strict_overflow_ops)] |
586 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).strict_add(1), ", stringify!($SelfT), "::MAX - 1);")] |
587 | /// ``` |
588 | /// |
589 | /// The following panics because of overflow: |
590 | /// |
591 | /// ```should_panic |
592 | /// #![feature(strict_overflow_ops)] |
593 | #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add(3);")] |
594 | /// ``` |
595 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
596 | #[must_use = "this returns the result of the operation, \ |
597 | without modifying the original"] |
598 | #[inline] |
599 | #[track_caller] |
600 | pub const fn strict_add(self, rhs: Self) -> Self { |
601 | let (a, b) = self.overflowing_add(rhs); |
602 | if b { overflow_panic::add() } else { a } |
603 | } |
604 | |
605 | /// Unchecked integer addition. Computes `self + rhs`, assuming overflow |
606 | /// cannot occur. |
607 | /// |
608 | /// Calling `x.unchecked_add(y)` is semantically equivalent to calling |
609 | /// `x.`[`checked_add`]`(y).`[`unwrap_unchecked`]`()`. |
610 | /// |
611 | /// If you're just trying to avoid the panic in debug mode, then **do not** |
612 | /// use this. Instead, you're looking for [`wrapping_add`]. |
613 | /// |
614 | /// # Safety |
615 | /// |
616 | /// This results in undefined behavior when |
617 | #[doc = concat!("`self + rhs > ", stringify!($SelfT), "::MAX` or `self + rhs < ", stringify!($SelfT), "::MIN`,")] |
618 | /// i.e. when [`checked_add`] would return `None`. |
619 | /// |
620 | /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked |
621 | #[doc = concat!("[`checked_add`]: ", stringify!($SelfT), "::checked_add")] |
622 | #[doc = concat!("[`wrapping_add`]: ", stringify!($SelfT), "::wrapping_add")] |
623 | #[stable(feature = "unchecked_math", since = "1.79.0")] |
624 | #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")] |
625 | #[must_use = "this returns the result of the operation, \ |
626 | without modifying the original"] |
627 | #[inline(always)] |
628 | #[track_caller] |
629 | pub const unsafe fn unchecked_add(self, rhs: Self) -> Self { |
630 | assert_unsafe_precondition!( |
631 | check_language_ub, |
632 | concat!(stringify!($SelfT), "::unchecked_add cannot overflow"), |
633 | ( |
634 | lhs: $SelfT = self, |
635 | rhs: $SelfT = rhs, |
636 | ) => !lhs.overflowing_add(rhs).1, |
637 | ); |
638 | |
639 | // SAFETY: this is guaranteed to be safe by the caller. |
640 | unsafe { |
641 | intrinsics::unchecked_add(self, rhs) |
642 | } |
643 | } |
644 | |
645 | /// Checked addition with a signed integer. Computes `self + rhs`, |
646 | /// returning `None` if overflow occurred. |
647 | /// |
648 | /// # Examples |
649 | /// |
650 | /// Basic usage: |
651 | /// |
652 | /// ``` |
653 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(2), Some(3));")] |
654 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_add_signed(-2), None);")] |
655 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add_signed(3), None);")] |
656 | /// ``` |
657 | #[stable(feature = "mixed_integer_ops", since = "1.66.0")] |
658 | #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")] |
659 | #[must_use = "this returns the result of the operation, \ |
660 | without modifying the original"] |
661 | #[inline] |
662 | pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> { |
663 | let (a, b) = self.overflowing_add_signed(rhs); |
664 | if intrinsics::unlikely(b) { None } else { Some(a) } |
665 | } |
666 | |
667 | /// Strict addition with a signed integer. Computes `self + rhs`, |
668 | /// panicking if overflow occurred. |
669 | /// |
670 | /// # Panics |
671 | /// |
672 | /// ## Overflow behavior |
673 | /// |
674 | /// This function will always panic on overflow, regardless of whether overflow checks are enabled. |
675 | /// |
676 | /// # Examples |
677 | /// |
678 | /// Basic usage: |
679 | /// |
680 | /// ``` |
681 | /// #![feature(strict_overflow_ops)] |
682 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_add_signed(2), 3);")] |
683 | /// ``` |
684 | /// |
685 | /// The following panic because of overflow: |
686 | /// |
687 | /// ```should_panic |
688 | /// #![feature(strict_overflow_ops)] |
689 | #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_add_signed(-2);")] |
690 | /// ``` |
691 | /// |
692 | /// ```should_panic |
693 | /// #![feature(strict_overflow_ops)] |
694 | #[doc = concat!("let _ = (", stringify!($SelfT), "::MAX - 2).strict_add_signed(3);")] |
695 | /// ``` |
696 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
697 | #[must_use = "this returns the result of the operation, \ |
698 | without modifying the original"] |
699 | #[inline] |
700 | #[track_caller] |
701 | pub const fn strict_add_signed(self, rhs: $SignedT) -> Self { |
702 | let (a, b) = self.overflowing_add_signed(rhs); |
703 | if b { overflow_panic::add() } else { a } |
704 | } |
705 | |
706 | /// Checked integer subtraction. Computes `self - rhs`, returning |
707 | /// `None` if overflow occurred. |
708 | /// |
709 | /// # Examples |
710 | /// |
711 | /// Basic usage: |
712 | /// |
713 | /// ``` |
714 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub(1), Some(0));")] |
715 | #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);")] |
716 | /// ``` |
717 | #[stable(feature = "rust1", since = "1.0.0")] |
718 | #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] |
719 | #[must_use = "this returns the result of the operation, \ |
720 | without modifying the original"] |
721 | #[inline] |
722 | pub const fn checked_sub(self, rhs: Self) -> Option<Self> { |
723 | // Per PR#103299, there's no advantage to the `overflowing` intrinsic |
724 | // for *unsigned* subtraction and we just emit the manual check anyway. |
725 | // Thus, rather than using `overflowing_sub` that produces a wrapping |
726 | // subtraction, check it ourself so we can use an unchecked one. |
727 | |
728 | if self < rhs { |
729 | None |
730 | } else { |
731 | // SAFETY: just checked this can't overflow |
732 | Some(unsafe { intrinsics::unchecked_sub(self, rhs) }) |
733 | } |
734 | } |
735 | |
736 | /// Strict integer subtraction. Computes `self - rhs`, panicking if |
737 | /// overflow occurred. |
738 | /// |
739 | /// # Panics |
740 | /// |
741 | /// ## Overflow behavior |
742 | /// |
743 | /// This function will always panic on overflow, regardless of whether overflow checks are enabled. |
744 | /// |
745 | /// # Examples |
746 | /// |
747 | /// Basic usage: |
748 | /// |
749 | /// ``` |
750 | /// #![feature(strict_overflow_ops)] |
751 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".strict_sub(1), 0);")] |
752 | /// ``` |
753 | /// |
754 | /// The following panics because of overflow: |
755 | /// |
756 | /// ```should_panic |
757 | /// #![feature(strict_overflow_ops)] |
758 | #[doc = concat!("let _ = 0", stringify!($SelfT), ".strict_sub(1);")] |
759 | /// ``` |
760 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
761 | #[must_use = "this returns the result of the operation, \ |
762 | without modifying the original"] |
763 | #[inline] |
764 | #[track_caller] |
765 | pub const fn strict_sub(self, rhs: Self) -> Self { |
766 | let (a, b) = self.overflowing_sub(rhs); |
767 | if b { overflow_panic::sub() } else { a } |
768 | } |
769 | |
770 | /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow |
771 | /// cannot occur. |
772 | /// |
773 | /// Calling `x.unchecked_sub(y)` is semantically equivalent to calling |
774 | /// `x.`[`checked_sub`]`(y).`[`unwrap_unchecked`]`()`. |
775 | /// |
776 | /// If you're just trying to avoid the panic in debug mode, then **do not** |
777 | /// use this. Instead, you're looking for [`wrapping_sub`]. |
778 | /// |
779 | /// If you find yourself writing code like this: |
780 | /// |
781 | /// ``` |
782 | /// # let foo = 30_u32; |
783 | /// # let bar = 20; |
784 | /// if foo >= bar { |
785 | /// // SAFETY: just checked it will not overflow |
786 | /// let diff = unsafe { foo.unchecked_sub(bar) }; |
787 | /// // ... use diff ... |
788 | /// } |
789 | /// ``` |
790 | /// |
791 | /// Consider changing it to |
792 | /// |
793 | /// ``` |
794 | /// # let foo = 30_u32; |
795 | /// # let bar = 20; |
796 | /// if let Some(diff) = foo.checked_sub(bar) { |
797 | /// // ... use diff ... |
798 | /// } |
799 | /// ``` |
800 | /// |
801 | /// As that does exactly the same thing -- including telling the optimizer |
802 | /// that the subtraction cannot overflow -- but avoids needing `unsafe`. |
803 | /// |
804 | /// # Safety |
805 | /// |
806 | /// This results in undefined behavior when |
807 | #[doc = concat!("`self - rhs > ", stringify!($SelfT), "::MAX` or `self - rhs < ", stringify!($SelfT), "::MIN`,")] |
808 | /// i.e. when [`checked_sub`] would return `None`. |
809 | /// |
810 | /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked |
811 | #[doc = concat!("[`checked_sub`]: ", stringify!($SelfT), "::checked_sub")] |
812 | #[doc = concat!("[`wrapping_sub`]: ", stringify!($SelfT), "::wrapping_sub")] |
813 | #[stable(feature = "unchecked_math", since = "1.79.0")] |
814 | #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")] |
815 | #[must_use = "this returns the result of the operation, \ |
816 | without modifying the original"] |
817 | #[inline(always)] |
818 | #[track_caller] |
819 | pub const unsafe fn unchecked_sub(self, rhs: Self) -> Self { |
820 | assert_unsafe_precondition!( |
821 | check_language_ub, |
822 | concat!(stringify!($SelfT), "::unchecked_sub cannot overflow"), |
823 | ( |
824 | lhs: $SelfT = self, |
825 | rhs: $SelfT = rhs, |
826 | ) => !lhs.overflowing_sub(rhs).1, |
827 | ); |
828 | |
829 | // SAFETY: this is guaranteed to be safe by the caller. |
830 | unsafe { |
831 | intrinsics::unchecked_sub(self, rhs) |
832 | } |
833 | } |
834 | |
835 | /// Checked subtraction with a signed integer. Computes `self - rhs`, |
836 | /// returning `None` if overflow occurred. |
837 | /// |
838 | /// # Examples |
839 | /// |
840 | /// Basic usage: |
841 | /// |
842 | /// ``` |
843 | /// #![feature(mixed_integer_ops_unsigned_sub)] |
844 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(2), None);")] |
845 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_sub_signed(-2), Some(3));")] |
846 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_sub_signed(-4), None);")] |
847 | /// ``` |
848 | #[unstable(feature = "mixed_integer_ops_unsigned_sub", issue = "126043")] |
849 | #[must_use = "this returns the result of the operation, \ |
850 | without modifying the original"] |
851 | #[inline] |
852 | pub const fn checked_sub_signed(self, rhs: $SignedT) -> Option<Self> { |
853 | let (res, overflow) = self.overflowing_sub_signed(rhs); |
854 | |
855 | if !overflow { |
856 | Some(res) |
857 | } else { |
858 | None |
859 | } |
860 | } |
861 | |
862 | #[doc = concat!( |
863 | "Checked integer subtraction. Computes `self - rhs` and checks if the result fits into an [`", |
864 | stringify!($SignedT), "`], returning `None` if overflow occurred." |
865 | )] |
866 | /// |
867 | /// # Examples |
868 | /// |
869 | /// Basic usage: |
870 | /// |
871 | /// ``` |
872 | /// #![feature(unsigned_signed_diff)] |
873 | #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_signed_diff(2), Some(8));")] |
874 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_signed_diff(10), Some(-8));")] |
875 | #[doc = concat!( |
876 | "assert_eq!(", |
877 | stringify!($SelfT), |
878 | "::MAX.checked_signed_diff(", |
879 | stringify!($SignedT), |
880 | "::MAX as ", |
881 | stringify!($SelfT), |
882 | "), None);" |
883 | )] |
884 | #[doc = concat!( |
885 | "assert_eq!((", |
886 | stringify!($SignedT), |
887 | "::MAX as ", |
888 | stringify!($SelfT), |
889 | ").checked_signed_diff(", |
890 | stringify!($SelfT), |
891 | "::MAX), Some(", |
892 | stringify!($SignedT), |
893 | "::MIN));" |
894 | )] |
895 | #[doc = concat!( |
896 | "assert_eq!((", |
897 | stringify!($SignedT), |
898 | "::MAX as ", |
899 | stringify!($SelfT), |
900 | " + 1).checked_signed_diff(0), None);" |
901 | )] |
902 | #[doc = concat!( |
903 | "assert_eq!(", |
904 | stringify!($SelfT), |
905 | "::MAX.checked_signed_diff(", |
906 | stringify!($SelfT), |
907 | "::MAX), Some(0));" |
908 | )] |
909 | /// ``` |
910 | #[unstable(feature = "unsigned_signed_diff", issue = "126041")] |
911 | #[inline] |
912 | pub const fn checked_signed_diff(self, rhs: Self) -> Option<$SignedT> { |
913 | let res = self.wrapping_sub(rhs) as $SignedT; |
914 | let overflow = (self >= rhs) == (res < 0); |
915 | |
916 | if !overflow { |
917 | Some(res) |
918 | } else { |
919 | None |
920 | } |
921 | } |
922 | |
923 | /// Checked integer multiplication. Computes `self * rhs`, returning |
924 | /// `None` if overflow occurred. |
925 | /// |
926 | /// # Examples |
927 | /// |
928 | /// Basic usage: |
929 | /// |
930 | /// ``` |
931 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_mul(1), Some(5));")] |
932 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);")] |
933 | /// ``` |
934 | #[stable(feature = "rust1", since = "1.0.0")] |
935 | #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] |
936 | #[must_use = "this returns the result of the operation, \ |
937 | without modifying the original"] |
938 | #[inline] |
939 | pub const fn checked_mul(self, rhs: Self) -> Option<Self> { |
940 | let (a, b) = self.overflowing_mul(rhs); |
941 | if intrinsics::unlikely(b) { None } else { Some(a) } |
942 | } |
943 | |
944 | /// Strict integer multiplication. Computes `self * rhs`, panicking if |
945 | /// overflow occurred. |
946 | /// |
947 | /// # Panics |
948 | /// |
949 | /// ## Overflow behavior |
950 | /// |
951 | /// This function will always panic on overflow, regardless of whether overflow checks are enabled. |
952 | /// |
953 | /// # Examples |
954 | /// |
955 | /// Basic usage: |
956 | /// |
957 | /// ``` |
958 | /// #![feature(strict_overflow_ops)] |
959 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".strict_mul(1), 5);")] |
960 | /// ``` |
961 | /// |
962 | /// The following panics because of overflow: |
963 | /// |
964 | /// ``` should_panic |
965 | /// #![feature(strict_overflow_ops)] |
966 | #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_mul(2);")] |
967 | /// ``` |
968 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
969 | #[must_use = "this returns the result of the operation, \ |
970 | without modifying the original"] |
971 | #[inline] |
972 | #[track_caller] |
973 | pub const fn strict_mul(self, rhs: Self) -> Self { |
974 | let (a, b) = self.overflowing_mul(rhs); |
975 | if b { overflow_panic::mul() } else { a } |
976 | } |
977 | |
978 | /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow |
979 | /// cannot occur. |
980 | /// |
981 | /// Calling `x.unchecked_mul(y)` is semantically equivalent to calling |
982 | /// `x.`[`checked_mul`]`(y).`[`unwrap_unchecked`]`()`. |
983 | /// |
984 | /// If you're just trying to avoid the panic in debug mode, then **do not** |
985 | /// use this. Instead, you're looking for [`wrapping_mul`]. |
986 | /// |
987 | /// # Safety |
988 | /// |
989 | /// This results in undefined behavior when |
990 | #[doc = concat!("`self * rhs > ", stringify!($SelfT), "::MAX` or `self * rhs < ", stringify!($SelfT), "::MIN`,")] |
991 | /// i.e. when [`checked_mul`] would return `None`. |
992 | /// |
993 | /// [`unwrap_unchecked`]: option/enum.Option.html#method.unwrap_unchecked |
994 | #[doc = concat!("[`checked_mul`]: ", stringify!($SelfT), "::checked_mul")] |
995 | #[doc = concat!("[`wrapping_mul`]: ", stringify!($SelfT), "::wrapping_mul")] |
996 | #[stable(feature = "unchecked_math", since = "1.79.0")] |
997 | #[rustc_const_stable(feature = "unchecked_math", since = "1.79.0")] |
998 | #[must_use = "this returns the result of the operation, \ |
999 | without modifying the original"] |
1000 | #[inline(always)] |
1001 | #[track_caller] |
1002 | pub const unsafe fn unchecked_mul(self, rhs: Self) -> Self { |
1003 | assert_unsafe_precondition!( |
1004 | check_language_ub, |
1005 | concat!(stringify!($SelfT), "::unchecked_mul cannot overflow"), |
1006 | ( |
1007 | lhs: $SelfT = self, |
1008 | rhs: $SelfT = rhs, |
1009 | ) => !lhs.overflowing_mul(rhs).1, |
1010 | ); |
1011 | |
1012 | // SAFETY: this is guaranteed to be safe by the caller. |
1013 | unsafe { |
1014 | intrinsics::unchecked_mul(self, rhs) |
1015 | } |
1016 | } |
1017 | |
1018 | /// Checked integer division. Computes `self / rhs`, returning `None` |
1019 | /// if `rhs == 0`. |
1020 | /// |
1021 | /// # Examples |
1022 | /// |
1023 | /// Basic usage: |
1024 | /// |
1025 | /// ``` |
1026 | #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div(2), Some(64));")] |
1027 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);")] |
1028 | /// ``` |
1029 | #[stable(feature = "rust1", since = "1.0.0")] |
1030 | #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")] |
1031 | #[must_use = "this returns the result of the operation, \ |
1032 | without modifying the original"] |
1033 | #[inline] |
1034 | pub const fn checked_div(self, rhs: Self) -> Option<Self> { |
1035 | if intrinsics::unlikely(rhs == 0) { |
1036 | None |
1037 | } else { |
1038 | // SAFETY: div by zero has been checked above and unsigned types have no other |
1039 | // failure modes for division |
1040 | Some(unsafe { intrinsics::unchecked_div(self, rhs) }) |
1041 | } |
1042 | } |
1043 | |
1044 | /// Strict integer division. Computes `self / rhs`. |
1045 | /// |
1046 | /// Strict division on unsigned types is just normal division. There's no |
1047 | /// way overflow could ever happen. This function exists so that all |
1048 | /// operations are accounted for in the strict operations. |
1049 | /// |
1050 | /// # Panics |
1051 | /// |
1052 | /// This function will panic if `rhs` is zero. |
1053 | /// |
1054 | /// # Examples |
1055 | /// |
1056 | /// Basic usage: |
1057 | /// |
1058 | /// ``` |
1059 | /// #![feature(strict_overflow_ops)] |
1060 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div(10), 10);")] |
1061 | /// ``` |
1062 | /// |
1063 | /// The following panics because of division by zero: |
1064 | /// |
1065 | /// ```should_panic |
1066 | /// #![feature(strict_overflow_ops)] |
1067 | #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div(0);")] |
1068 | /// ``` |
1069 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
1070 | #[must_use = "this returns the result of the operation, \ |
1071 | without modifying the original"] |
1072 | #[inline(always)] |
1073 | #[track_caller] |
1074 | pub const fn strict_div(self, rhs: Self) -> Self { |
1075 | self / rhs |
1076 | } |
1077 | |
1078 | /// Checked Euclidean division. Computes `self.div_euclid(rhs)`, returning `None` |
1079 | /// if `rhs == 0`. |
1080 | /// |
1081 | /// # Examples |
1082 | /// |
1083 | /// Basic usage: |
1084 | /// |
1085 | /// ``` |
1086 | #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".checked_div_euclid(2), Some(64));")] |
1087 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);")] |
1088 | /// ``` |
1089 | #[stable(feature = "euclidean_division", since = "1.38.0")] |
1090 | #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] |
1091 | #[must_use = "this returns the result of the operation, \ |
1092 | without modifying the original"] |
1093 | #[inline] |
1094 | pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> { |
1095 | if intrinsics::unlikely(rhs == 0) { |
1096 | None |
1097 | } else { |
1098 | Some(self.div_euclid(rhs)) |
1099 | } |
1100 | } |
1101 | |
1102 | /// Strict Euclidean division. Computes `self.div_euclid(rhs)`. |
1103 | /// |
1104 | /// Strict division on unsigned types is just normal division. There's no |
1105 | /// way overflow could ever happen. This function exists so that all |
1106 | /// operations are accounted for in the strict operations. Since, for the |
1107 | /// positive integers, all common definitions of division are equal, this |
1108 | /// is exactly equal to `self.strict_div(rhs)`. |
1109 | /// |
1110 | /// # Panics |
1111 | /// |
1112 | /// This function will panic if `rhs` is zero. |
1113 | /// |
1114 | /// # Examples |
1115 | /// |
1116 | /// Basic usage: |
1117 | /// |
1118 | /// ``` |
1119 | /// #![feature(strict_overflow_ops)] |
1120 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_div_euclid(10), 10);")] |
1121 | /// ``` |
1122 | /// The following panics because of division by zero: |
1123 | /// |
1124 | /// ```should_panic |
1125 | /// #![feature(strict_overflow_ops)] |
1126 | #[doc = concat!("let _ = (1", stringify!($SelfT), ").strict_div_euclid(0);")] |
1127 | /// ``` |
1128 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
1129 | #[must_use = "this returns the result of the operation, \ |
1130 | without modifying the original"] |
1131 | #[inline(always)] |
1132 | #[track_caller] |
1133 | pub const fn strict_div_euclid(self, rhs: Self) -> Self { |
1134 | self / rhs |
1135 | } |
1136 | |
1137 | /// Checked integer division without remainder. Computes `self / rhs`. |
1138 | /// |
1139 | /// # Panics |
1140 | /// |
1141 | /// This function will panic if `rhs == 0` or `self % rhs != 0`. |
1142 | /// |
1143 | /// # Examples |
1144 | /// |
1145 | /// Basic usage: |
1146 | /// |
1147 | /// ``` |
1148 | /// #![feature(exact_div)] |
1149 | #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".exact_div(2), 32);")] |
1150 | #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".exact_div(32), 2);")] |
1151 | /// ``` |
1152 | /// |
1153 | /// ```should_panic |
1154 | /// #![feature(exact_div)] |
1155 | #[doc = concat!("let _ = 65", stringify!($SelfT), ".exact_div(2);")] |
1156 | /// ``` |
1157 | #[unstable( |
1158 | feature = "exact_div", |
1159 | issue = "139911", |
1160 | )] |
1161 | #[must_use = "this returns the result of the operation, \ |
1162 | without modifying the original"] |
1163 | #[inline] |
1164 | pub const fn checked_exact_div(self, rhs: Self) -> Option<Self> { |
1165 | if intrinsics::unlikely(rhs == 0) { |
1166 | None |
1167 | } else { |
1168 | // SAFETY: division by zero is checked above |
1169 | unsafe { |
1170 | if intrinsics::unlikely(intrinsics::unchecked_rem(self, rhs) != 0) { |
1171 | None |
1172 | } else { |
1173 | Some(intrinsics::exact_div(self, rhs)) |
1174 | } |
1175 | } |
1176 | } |
1177 | } |
1178 | |
1179 | /// Checked integer division without remainder. Computes `self / rhs`. |
1180 | /// |
1181 | /// # Panics |
1182 | /// |
1183 | /// This function will panic if `rhs == 0` or `self % rhs != 0`. |
1184 | /// |
1185 | /// # Examples |
1186 | /// |
1187 | /// Basic usage: |
1188 | /// |
1189 | /// ``` |
1190 | /// #![feature(exact_div)] |
1191 | #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".exact_div(2), 32);")] |
1192 | #[doc = concat!("assert_eq!(64", stringify!($SelfT), ".exact_div(32), 2);")] |
1193 | /// ``` |
1194 | /// |
1195 | /// ```should_panic |
1196 | /// #![feature(exact_div)] |
1197 | #[doc = concat!("let _ = 65", stringify!($SelfT), ".exact_div(2);")] |
1198 | /// ``` |
1199 | #[unstable( |
1200 | feature = "exact_div", |
1201 | issue = "139911", |
1202 | )] |
1203 | #[must_use = "this returns the result of the operation, \ |
1204 | without modifying the original"] |
1205 | #[inline] |
1206 | pub const fn exact_div(self, rhs: Self) -> Self { |
1207 | match self.checked_exact_div(rhs) { |
1208 | Some(x) => x, |
1209 | None => panic!("Failed to divide without remainder"), |
1210 | } |
1211 | } |
1212 | |
1213 | /// Unchecked integer division without remainder. Computes `self / rhs`. |
1214 | /// |
1215 | /// # Safety |
1216 | /// |
1217 | /// This results in undefined behavior when `rhs == 0` or `self % rhs != 0`, |
1218 | /// i.e. when [`checked_exact_div`](Self::checked_exact_div) would return `None`. |
1219 | #[unstable( |
1220 | feature = "exact_div", |
1221 | issue = "139911", |
1222 | )] |
1223 | #[must_use = "this returns the result of the operation, \ |
1224 | without modifying the original"] |
1225 | #[inline] |
1226 | pub const unsafe fn unchecked_exact_div(self, rhs: Self) -> Self { |
1227 | assert_unsafe_precondition!( |
1228 | check_language_ub, |
1229 | concat!(stringify!($SelfT), "::unchecked_exact_div divide by zero or leave a remainder"), |
1230 | ( |
1231 | lhs: $SelfT = self, |
1232 | rhs: $SelfT = rhs, |
1233 | ) => rhs > 0 && lhs % rhs == 0, |
1234 | ); |
1235 | // SAFETY: Same precondition |
1236 | unsafe { intrinsics::exact_div(self, rhs) } |
1237 | } |
1238 | |
1239 | /// Checked integer remainder. Computes `self % rhs`, returning `None` |
1240 | /// if `rhs == 0`. |
1241 | /// |
1242 | /// # Examples |
1243 | /// |
1244 | /// Basic usage: |
1245 | /// |
1246 | /// ``` |
1247 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(2), Some(1));")] |
1248 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);")] |
1249 | /// ``` |
1250 | #[stable(feature = "wrapping", since = "1.7.0")] |
1251 | #[rustc_const_stable(feature = "const_checked_int_div", since = "1.52.0")] |
1252 | #[must_use = "this returns the result of the operation, \ |
1253 | without modifying the original"] |
1254 | #[inline] |
1255 | pub const fn checked_rem(self, rhs: Self) -> Option<Self> { |
1256 | if intrinsics::unlikely(rhs == 0) { |
1257 | None |
1258 | } else { |
1259 | // SAFETY: div by zero has been checked above and unsigned types have no other |
1260 | // failure modes for division |
1261 | Some(unsafe { intrinsics::unchecked_rem(self, rhs) }) |
1262 | } |
1263 | } |
1264 | |
1265 | /// Strict integer remainder. Computes `self % rhs`. |
1266 | /// |
1267 | /// Strict remainder calculation on unsigned types is just the regular |
1268 | /// remainder calculation. There's no way overflow could ever happen. |
1269 | /// This function exists so that all operations are accounted for in the |
1270 | /// strict operations. |
1271 | /// |
1272 | /// # Panics |
1273 | /// |
1274 | /// This function will panic if `rhs` is zero. |
1275 | /// |
1276 | /// # Examples |
1277 | /// |
1278 | /// Basic usage: |
1279 | /// |
1280 | /// ``` |
1281 | /// #![feature(strict_overflow_ops)] |
1282 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem(10), 0);")] |
1283 | /// ``` |
1284 | /// |
1285 | /// The following panics because of division by zero: |
1286 | /// |
1287 | /// ```should_panic |
1288 | /// #![feature(strict_overflow_ops)] |
1289 | #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem(0);")] |
1290 | /// ``` |
1291 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
1292 | #[must_use = "this returns the result of the operation, \ |
1293 | without modifying the original"] |
1294 | #[inline(always)] |
1295 | #[track_caller] |
1296 | pub const fn strict_rem(self, rhs: Self) -> Self { |
1297 | self % rhs |
1298 | } |
1299 | |
1300 | /// Checked Euclidean modulo. Computes `self.rem_euclid(rhs)`, returning `None` |
1301 | /// if `rhs == 0`. |
1302 | /// |
1303 | /// # Examples |
1304 | /// |
1305 | /// Basic usage: |
1306 | /// |
1307 | /// ``` |
1308 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(2), Some(1));")] |
1309 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);")] |
1310 | /// ``` |
1311 | #[stable(feature = "euclidean_division", since = "1.38.0")] |
1312 | #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] |
1313 | #[must_use = "this returns the result of the operation, \ |
1314 | without modifying the original"] |
1315 | #[inline] |
1316 | pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> { |
1317 | if intrinsics::unlikely(rhs == 0) { |
1318 | None |
1319 | } else { |
1320 | Some(self.rem_euclid(rhs)) |
1321 | } |
1322 | } |
1323 | |
1324 | /// Strict Euclidean modulo. Computes `self.rem_euclid(rhs)`. |
1325 | /// |
1326 | /// Strict modulo calculation on unsigned types is just the regular |
1327 | /// remainder calculation. There's no way overflow could ever happen. |
1328 | /// This function exists so that all operations are accounted for in the |
1329 | /// strict operations. Since, for the positive integers, all common |
1330 | /// definitions of division are equal, this is exactly equal to |
1331 | /// `self.strict_rem(rhs)`. |
1332 | /// |
1333 | /// # Panics |
1334 | /// |
1335 | /// This function will panic if `rhs` is zero. |
1336 | /// |
1337 | /// # Examples |
1338 | /// |
1339 | /// Basic usage: |
1340 | /// |
1341 | /// ``` |
1342 | /// #![feature(strict_overflow_ops)] |
1343 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".strict_rem_euclid(10), 0);")] |
1344 | /// ``` |
1345 | /// |
1346 | /// The following panics because of division by zero: |
1347 | /// |
1348 | /// ```should_panic |
1349 | /// #![feature(strict_overflow_ops)] |
1350 | #[doc = concat!("let _ = 5", stringify!($SelfT), ".strict_rem_euclid(0);")] |
1351 | /// ``` |
1352 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
1353 | #[must_use = "this returns the result of the operation, \ |
1354 | without modifying the original"] |
1355 | #[inline(always)] |
1356 | #[track_caller] |
1357 | pub const fn strict_rem_euclid(self, rhs: Self) -> Self { |
1358 | self % rhs |
1359 | } |
1360 | |
1361 | /// Same value as `self | other`, but UB if any bit position is set in both inputs. |
1362 | /// |
1363 | /// This is a situational micro-optimization for places where you'd rather |
1364 | /// use addition on some platforms and bitwise or on other platforms, based |
1365 | /// on exactly which instructions combine better with whatever else you're |
1366 | /// doing. Note that there's no reason to bother using this for places |
1367 | /// where it's clear from the operations involved that they can't overlap. |
1368 | /// For example, if you're combining `u16`s into a `u32` with |
1369 | /// `((a as u32) << 16) | (b as u32)`, that's fine, as the backend will |
1370 | /// know those sides of the `|` are disjoint without needing help. |
1371 | /// |
1372 | /// # Examples |
1373 | /// |
1374 | /// ``` |
1375 | /// #![feature(disjoint_bitor)] |
1376 | /// |
1377 | /// // SAFETY: `1` and `4` have no bits in common. |
1378 | /// unsafe { |
1379 | #[doc = concat!(" assert_eq!(1_", stringify!($SelfT), ".unchecked_disjoint_bitor(4), 5);")] |
1380 | /// } |
1381 | /// ``` |
1382 | /// |
1383 | /// # Safety |
1384 | /// |
1385 | /// Requires that `(self & other) == 0`, otherwise it's immediate UB. |
1386 | /// |
1387 | /// Equivalently, requires that `(self | other) == (self + other)`. |
1388 | #[unstable(feature = "disjoint_bitor", issue = "135758")] |
1389 | #[rustc_const_unstable(feature = "disjoint_bitor", issue = "135758")] |
1390 | #[inline] |
1391 | pub const unsafe fn unchecked_disjoint_bitor(self, other: Self) -> Self { |
1392 | assert_unsafe_precondition!( |
1393 | check_language_ub, |
1394 | concat!(stringify!($SelfT), "::unchecked_disjoint_bitor cannot have overlapping bits"), |
1395 | ( |
1396 | lhs: $SelfT = self, |
1397 | rhs: $SelfT = other, |
1398 | ) => (lhs & rhs) == 0, |
1399 | ); |
1400 | |
1401 | // SAFETY: Same precondition |
1402 | unsafe { intrinsics::disjoint_bitor(self, other) } |
1403 | } |
1404 | |
1405 | /// Returns the logarithm of the number with respect to an arbitrary base, |
1406 | /// rounded down. |
1407 | /// |
1408 | /// This method might not be optimized owing to implementation details; |
1409 | /// `ilog2` can produce results more efficiently for base 2, and `ilog10` |
1410 | /// can produce results more efficiently for base 10. |
1411 | /// |
1412 | /// # Panics |
1413 | /// |
1414 | /// This function will panic if `self` is zero, or if `base` is less than 2. |
1415 | /// |
1416 | /// # Examples |
1417 | /// |
1418 | /// ``` |
1419 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".ilog(5), 1);")] |
1420 | /// ``` |
1421 | #[stable(feature = "int_log", since = "1.67.0")] |
1422 | #[rustc_const_stable(feature = "int_log", since = "1.67.0")] |
1423 | #[must_use = "this returns the result of the operation, \ |
1424 | without modifying the original"] |
1425 | #[inline] |
1426 | #[track_caller] |
1427 | pub const fn ilog(self, base: Self) -> u32 { |
1428 | assert!(base >= 2, "base of integer logarithm must be at least 2"); |
1429 | if let Some(log) = self.checked_ilog(base) { |
1430 | log |
1431 | } else { |
1432 | int_log10::panic_for_nonpositive_argument() |
1433 | } |
1434 | } |
1435 | |
1436 | /// Returns the base 2 logarithm of the number, rounded down. |
1437 | /// |
1438 | /// # Panics |
1439 | /// |
1440 | /// This function will panic if `self` is zero. |
1441 | /// |
1442 | /// # Examples |
1443 | /// |
1444 | /// ``` |
1445 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".ilog2(), 1);")] |
1446 | /// ``` |
1447 | #[stable(feature = "int_log", since = "1.67.0")] |
1448 | #[rustc_const_stable(feature = "int_log", since = "1.67.0")] |
1449 | #[must_use = "this returns the result of the operation, \ |
1450 | without modifying the original"] |
1451 | #[inline] |
1452 | #[track_caller] |
1453 | pub const fn ilog2(self) -> u32 { |
1454 | if let Some(log) = self.checked_ilog2() { |
1455 | log |
1456 | } else { |
1457 | int_log10::panic_for_nonpositive_argument() |
1458 | } |
1459 | } |
1460 | |
1461 | /// Returns the base 10 logarithm of the number, rounded down. |
1462 | /// |
1463 | /// # Panics |
1464 | /// |
1465 | /// This function will panic if `self` is zero. |
1466 | /// |
1467 | /// # Example |
1468 | /// |
1469 | /// ``` |
1470 | #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".ilog10(), 1);")] |
1471 | /// ``` |
1472 | #[stable(feature = "int_log", since = "1.67.0")] |
1473 | #[rustc_const_stable(feature = "int_log", since = "1.67.0")] |
1474 | #[must_use = "this returns the result of the operation, \ |
1475 | without modifying the original"] |
1476 | #[inline] |
1477 | #[track_caller] |
1478 | pub const fn ilog10(self) -> u32 { |
1479 | if let Some(log) = self.checked_ilog10() { |
1480 | log |
1481 | } else { |
1482 | int_log10::panic_for_nonpositive_argument() |
1483 | } |
1484 | } |
1485 | |
1486 | /// Returns the logarithm of the number with respect to an arbitrary base, |
1487 | /// rounded down. |
1488 | /// |
1489 | /// Returns `None` if the number is zero, or if the base is not at least 2. |
1490 | /// |
1491 | /// This method might not be optimized owing to implementation details; |
1492 | /// `checked_ilog2` can produce results more efficiently for base 2, and |
1493 | /// `checked_ilog10` can produce results more efficiently for base 10. |
1494 | /// |
1495 | /// # Examples |
1496 | /// |
1497 | /// ``` |
1498 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".checked_ilog(5), Some(1));")] |
1499 | /// ``` |
1500 | #[stable(feature = "int_log", since = "1.67.0")] |
1501 | #[rustc_const_stable(feature = "int_log", since = "1.67.0")] |
1502 | #[must_use = "this returns the result of the operation, \ |
1503 | without modifying the original"] |
1504 | #[inline] |
1505 | pub const fn checked_ilog(self, base: Self) -> Option<u32> { |
1506 | if self <= 0 || base <= 1 { |
1507 | None |
1508 | } else if self < base { |
1509 | Some(0) |
1510 | } else { |
1511 | // Since base >= self, n >= 1 |
1512 | let mut n = 1; |
1513 | let mut r = base; |
1514 | |
1515 | // Optimization for 128 bit wide integers. |
1516 | if Self::BITS == 128 { |
1517 | // The following is a correct lower bound for ⌊log(base,self)⌋ because |
1518 | // |
1519 | // log(base,self) = log(2,self) / log(2,base) |
1520 | // ≥ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1) |
1521 | // |
1522 | // hence |
1523 | // |
1524 | // ⌊log(base,self)⌋ ≥ ⌊ ⌊log(2,self)⌋ / (⌊log(2,base)⌋ + 1) ⌋ . |
1525 | n = self.ilog2() / (base.ilog2() + 1); |
1526 | r = base.pow(n); |
1527 | } |
1528 | |
1529 | while r <= self / base { |
1530 | n += 1; |
1531 | r *= base; |
1532 | } |
1533 | Some(n) |
1534 | } |
1535 | } |
1536 | |
1537 | /// Returns the base 2 logarithm of the number, rounded down. |
1538 | /// |
1539 | /// Returns `None` if the number is zero. |
1540 | /// |
1541 | /// # Examples |
1542 | /// |
1543 | /// ``` |
1544 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_ilog2(), Some(1));")] |
1545 | /// ``` |
1546 | #[stable(feature = "int_log", since = "1.67.0")] |
1547 | #[rustc_const_stable(feature = "int_log", since = "1.67.0")] |
1548 | #[must_use = "this returns the result of the operation, \ |
1549 | without modifying the original"] |
1550 | #[inline] |
1551 | pub const fn checked_ilog2(self) -> Option<u32> { |
1552 | match NonZero::new(self) { |
1553 | Some(x) => Some(x.ilog2()), |
1554 | None => None, |
1555 | } |
1556 | } |
1557 | |
1558 | /// Returns the base 10 logarithm of the number, rounded down. |
1559 | /// |
1560 | /// Returns `None` if the number is zero. |
1561 | /// |
1562 | /// # Examples |
1563 | /// |
1564 | /// ``` |
1565 | #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".checked_ilog10(), Some(1));")] |
1566 | /// ``` |
1567 | #[stable(feature = "int_log", since = "1.67.0")] |
1568 | #[rustc_const_stable(feature = "int_log", since = "1.67.0")] |
1569 | #[must_use = "this returns the result of the operation, \ |
1570 | without modifying the original"] |
1571 | #[inline] |
1572 | pub const fn checked_ilog10(self) -> Option<u32> { |
1573 | match NonZero::new(self) { |
1574 | Some(x) => Some(x.ilog10()), |
1575 | None => None, |
1576 | } |
1577 | } |
1578 | |
1579 | /// Checked negation. Computes `-self`, returning `None` unless `self == |
1580 | /// 0`. |
1581 | /// |
1582 | /// Note that negating any positive integer will overflow. |
1583 | /// |
1584 | /// # Examples |
1585 | /// |
1586 | /// Basic usage: |
1587 | /// |
1588 | /// ``` |
1589 | #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".checked_neg(), Some(0));")] |
1590 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);")] |
1591 | /// ``` |
1592 | #[stable(feature = "wrapping", since = "1.7.0")] |
1593 | #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] |
1594 | #[must_use = "this returns the result of the operation, \ |
1595 | without modifying the original"] |
1596 | #[inline] |
1597 | pub const fn checked_neg(self) -> Option<Self> { |
1598 | let (a, b) = self.overflowing_neg(); |
1599 | if intrinsics::unlikely(b) { None } else { Some(a) } |
1600 | } |
1601 | |
1602 | /// Strict negation. Computes `-self`, panicking unless `self == |
1603 | /// 0`. |
1604 | /// |
1605 | /// Note that negating any positive integer will overflow. |
1606 | /// |
1607 | /// # Panics |
1608 | /// |
1609 | /// ## Overflow behavior |
1610 | /// |
1611 | /// This function will always panic on overflow, regardless of whether overflow checks are enabled. |
1612 | /// |
1613 | /// # Examples |
1614 | /// |
1615 | /// Basic usage: |
1616 | /// |
1617 | /// ``` |
1618 | /// #![feature(strict_overflow_ops)] |
1619 | #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".strict_neg(), 0);")] |
1620 | /// ``` |
1621 | /// |
1622 | /// The following panics because of overflow: |
1623 | /// |
1624 | /// ```should_panic |
1625 | /// #![feature(strict_overflow_ops)] |
1626 | #[doc = concat!("let _ = 1", stringify!($SelfT), ".strict_neg();")] |
1627 | /// |
1628 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
1629 | #[must_use = "this returns the result of the operation, \ |
1630 | without modifying the original"] |
1631 | #[inline] |
1632 | #[track_caller] |
1633 | pub const fn strict_neg(self) -> Self { |
1634 | let (a, b) = self.overflowing_neg(); |
1635 | if b { overflow_panic::neg() } else { a } |
1636 | } |
1637 | |
1638 | /// Checked shift left. Computes `self << rhs`, returning `None` |
1639 | /// if `rhs` is larger than or equal to the number of bits in `self`. |
1640 | /// |
1641 | /// # Examples |
1642 | /// |
1643 | /// Basic usage: |
1644 | /// |
1645 | /// ``` |
1646 | #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".checked_shl(4), Some(0x10));")] |
1647 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);")] |
1648 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shl(", stringify!($BITS_MINUS_ONE), "), Some(0));")] |
1649 | /// ``` |
1650 | #[stable(feature = "wrapping", since = "1.7.0")] |
1651 | #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] |
1652 | #[must_use = "this returns the result of the operation, \ |
1653 | without modifying the original"] |
1654 | #[inline] |
1655 | pub const fn checked_shl(self, rhs: u32) -> Option<Self> { |
1656 | // Not using overflowing_shl as that's a wrapping shift |
1657 | if rhs < Self::BITS { |
1658 | // SAFETY: just checked the RHS is in-range |
1659 | Some(unsafe { self.unchecked_shl(rhs) }) |
1660 | } else { |
1661 | None |
1662 | } |
1663 | } |
1664 | |
1665 | /// Strict shift left. Computes `self << rhs`, panicking if `rhs` is larger |
1666 | /// than or equal to the number of bits in `self`. |
1667 | /// |
1668 | /// # Panics |
1669 | /// |
1670 | /// ## Overflow behavior |
1671 | /// |
1672 | /// This function will always panic on overflow, regardless of whether overflow checks are enabled. |
1673 | /// |
1674 | /// # Examples |
1675 | /// |
1676 | /// Basic usage: |
1677 | /// |
1678 | /// ``` |
1679 | /// #![feature(strict_overflow_ops)] |
1680 | #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".strict_shl(4), 0x10);")] |
1681 | /// ``` |
1682 | /// |
1683 | /// The following panics because of overflow: |
1684 | /// |
1685 | /// ```should_panic |
1686 | /// #![feature(strict_overflow_ops)] |
1687 | #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shl(129);")] |
1688 | /// ``` |
1689 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
1690 | #[must_use = "this returns the result of the operation, \ |
1691 | without modifying the original"] |
1692 | #[inline] |
1693 | #[track_caller] |
1694 | pub const fn strict_shl(self, rhs: u32) -> Self { |
1695 | let (a, b) = self.overflowing_shl(rhs); |
1696 | if b { overflow_panic::shl() } else { a } |
1697 | } |
1698 | |
1699 | /// Unchecked shift left. Computes `self << rhs`, assuming that |
1700 | /// `rhs` is less than the number of bits in `self`. |
1701 | /// |
1702 | /// # Safety |
1703 | /// |
1704 | /// This results in undefined behavior if `rhs` is larger than |
1705 | /// or equal to the number of bits in `self`, |
1706 | /// i.e. when [`checked_shl`] would return `None`. |
1707 | /// |
1708 | #[doc = concat!("[`checked_shl`]: ", stringify!($SelfT), "::checked_shl")] |
1709 | #[unstable( |
1710 | feature = "unchecked_shifts", |
1711 | reason = "niche optimization path", |
1712 | issue = "85122", |
1713 | )] |
1714 | #[must_use = "this returns the result of the operation, \ |
1715 | without modifying the original"] |
1716 | #[inline(always)] |
1717 | #[track_caller] |
1718 | pub const unsafe fn unchecked_shl(self, rhs: u32) -> Self { |
1719 | assert_unsafe_precondition!( |
1720 | check_language_ub, |
1721 | concat!(stringify!($SelfT), "::unchecked_shl cannot overflow"), |
1722 | ( |
1723 | rhs: u32 = rhs, |
1724 | ) => rhs < <$ActualT>::BITS, |
1725 | ); |
1726 | |
1727 | // SAFETY: this is guaranteed to be safe by the caller. |
1728 | unsafe { |
1729 | intrinsics::unchecked_shl(self, rhs) |
1730 | } |
1731 | } |
1732 | |
1733 | /// Unbounded shift left. Computes `self << rhs`, without bounding the value of `rhs`. |
1734 | /// |
1735 | /// If `rhs` is larger or equal to the number of bits in `self`, |
1736 | /// the entire value is shifted out, and `0` is returned. |
1737 | /// |
1738 | /// # Examples |
1739 | /// |
1740 | /// Basic usage: |
1741 | /// ``` |
1742 | #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(4), 0x10);")] |
1743 | #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".unbounded_shl(129), 0);")] |
1744 | /// ``` |
1745 | #[stable(feature = "unbounded_shifts", since = "1.87.0")] |
1746 | #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")] |
1747 | #[must_use = "this returns the result of the operation, \ |
1748 | without modifying the original"] |
1749 | #[inline] |
1750 | pub const fn unbounded_shl(self, rhs: u32) -> $SelfT{ |
1751 | if rhs < Self::BITS { |
1752 | // SAFETY: |
1753 | // rhs is just checked to be in-range above |
1754 | unsafe { self.unchecked_shl(rhs) } |
1755 | } else { |
1756 | 0 |
1757 | } |
1758 | } |
1759 | |
1760 | /// Checked shift right. Computes `self >> rhs`, returning `None` |
1761 | /// if `rhs` is larger than or equal to the number of bits in `self`. |
1762 | /// |
1763 | /// # Examples |
1764 | /// |
1765 | /// Basic usage: |
1766 | /// |
1767 | /// ``` |
1768 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(4), Some(0x1));")] |
1769 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);")] |
1770 | /// ``` |
1771 | #[stable(feature = "wrapping", since = "1.7.0")] |
1772 | #[rustc_const_stable(feature = "const_checked_int_methods", since = "1.47.0")] |
1773 | #[must_use = "this returns the result of the operation, \ |
1774 | without modifying the original"] |
1775 | #[inline] |
1776 | pub const fn checked_shr(self, rhs: u32) -> Option<Self> { |
1777 | // Not using overflowing_shr as that's a wrapping shift |
1778 | if rhs < Self::BITS { |
1779 | // SAFETY: just checked the RHS is in-range |
1780 | Some(unsafe { self.unchecked_shr(rhs) }) |
1781 | } else { |
1782 | None |
1783 | } |
1784 | } |
1785 | |
1786 | /// Strict shift right. Computes `self >> rhs`, panicking `rhs` is |
1787 | /// larger than or equal to the number of bits in `self`. |
1788 | /// |
1789 | /// # Panics |
1790 | /// |
1791 | /// ## Overflow behavior |
1792 | /// |
1793 | /// This function will always panic on overflow, regardless of whether overflow checks are enabled. |
1794 | /// |
1795 | /// # Examples |
1796 | /// |
1797 | /// Basic usage: |
1798 | /// |
1799 | /// ``` |
1800 | /// #![feature(strict_overflow_ops)] |
1801 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".strict_shr(4), 0x1);")] |
1802 | /// ``` |
1803 | /// |
1804 | /// The following panics because of overflow: |
1805 | /// |
1806 | /// ```should_panic |
1807 | /// #![feature(strict_overflow_ops)] |
1808 | #[doc = concat!("let _ = 0x10", stringify!($SelfT), ".strict_shr(129);")] |
1809 | /// ``` |
1810 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
1811 | #[must_use = "this returns the result of the operation, \ |
1812 | without modifying the original"] |
1813 | #[inline] |
1814 | #[track_caller] |
1815 | pub const fn strict_shr(self, rhs: u32) -> Self { |
1816 | let (a, b) = self.overflowing_shr(rhs); |
1817 | if b { overflow_panic::shr() } else { a } |
1818 | } |
1819 | |
1820 | /// Unchecked shift right. Computes `self >> rhs`, assuming that |
1821 | /// `rhs` is less than the number of bits in `self`. |
1822 | /// |
1823 | /// # Safety |
1824 | /// |
1825 | /// This results in undefined behavior if `rhs` is larger than |
1826 | /// or equal to the number of bits in `self`, |
1827 | /// i.e. when [`checked_shr`] would return `None`. |
1828 | /// |
1829 | #[doc = concat!("[`checked_shr`]: ", stringify!($SelfT), "::checked_shr")] |
1830 | #[unstable( |
1831 | feature = "unchecked_shifts", |
1832 | reason = "niche optimization path", |
1833 | issue = "85122", |
1834 | )] |
1835 | #[must_use = "this returns the result of the operation, \ |
1836 | without modifying the original"] |
1837 | #[inline(always)] |
1838 | #[track_caller] |
1839 | pub const unsafe fn unchecked_shr(self, rhs: u32) -> Self { |
1840 | assert_unsafe_precondition!( |
1841 | check_language_ub, |
1842 | concat!(stringify!($SelfT), "::unchecked_shr cannot overflow"), |
1843 | ( |
1844 | rhs: u32 = rhs, |
1845 | ) => rhs < <$ActualT>::BITS, |
1846 | ); |
1847 | |
1848 | // SAFETY: this is guaranteed to be safe by the caller. |
1849 | unsafe { |
1850 | intrinsics::unchecked_shr(self, rhs) |
1851 | } |
1852 | } |
1853 | |
1854 | /// Unbounded shift right. Computes `self >> rhs`, without bounding the value of `rhs`. |
1855 | /// |
1856 | /// If `rhs` is larger or equal to the number of bits in `self`, |
1857 | /// the entire value is shifted out, and `0` is returned. |
1858 | /// |
1859 | /// # Examples |
1860 | /// |
1861 | /// Basic usage: |
1862 | /// ``` |
1863 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(4), 0x1);")] |
1864 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".unbounded_shr(129), 0);")] |
1865 | /// ``` |
1866 | #[stable(feature = "unbounded_shifts", since = "1.87.0")] |
1867 | #[rustc_const_stable(feature = "unbounded_shifts", since = "1.87.0")] |
1868 | #[must_use = "this returns the result of the operation, \ |
1869 | without modifying the original"] |
1870 | #[inline] |
1871 | pub const fn unbounded_shr(self, rhs: u32) -> $SelfT{ |
1872 | if rhs < Self::BITS { |
1873 | // SAFETY: |
1874 | // rhs is just checked to be in-range above |
1875 | unsafe { self.unchecked_shr(rhs) } |
1876 | } else { |
1877 | 0 |
1878 | } |
1879 | } |
1880 | |
1881 | /// Checked exponentiation. Computes `self.pow(exp)`, returning `None` if |
1882 | /// overflow occurred. |
1883 | /// |
1884 | /// # Examples |
1885 | /// |
1886 | /// Basic usage: |
1887 | /// |
1888 | /// ``` |
1889 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_pow(5), Some(32));")] |
1890 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_pow(2), None);")] |
1891 | /// ``` |
1892 | #[stable(feature = "no_panic_pow", since = "1.34.0")] |
1893 | #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] |
1894 | #[must_use = "this returns the result of the operation, \ |
1895 | without modifying the original"] |
1896 | #[inline] |
1897 | pub const fn checked_pow(self, mut exp: u32) -> Option<Self> { |
1898 | if exp == 0 { |
1899 | return Some(1); |
1900 | } |
1901 | let mut base = self; |
1902 | let mut acc: Self = 1; |
1903 | |
1904 | loop { |
1905 | if (exp & 1) == 1 { |
1906 | acc = try_opt!(acc.checked_mul(base)); |
1907 | // since exp!=0, finally the exp must be 1. |
1908 | if exp == 1 { |
1909 | return Some(acc); |
1910 | } |
1911 | } |
1912 | exp /= 2; |
1913 | base = try_opt!(base.checked_mul(base)); |
1914 | } |
1915 | } |
1916 | |
1917 | /// Strict exponentiation. Computes `self.pow(exp)`, panicking if |
1918 | /// overflow occurred. |
1919 | /// |
1920 | /// # Panics |
1921 | /// |
1922 | /// ## Overflow behavior |
1923 | /// |
1924 | /// This function will always panic on overflow, regardless of whether overflow checks are enabled. |
1925 | /// |
1926 | /// # Examples |
1927 | /// |
1928 | /// Basic usage: |
1929 | /// |
1930 | /// ``` |
1931 | /// #![feature(strict_overflow_ops)] |
1932 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".strict_pow(5), 32);")] |
1933 | /// ``` |
1934 | /// |
1935 | /// The following panics because of overflow: |
1936 | /// |
1937 | /// ```should_panic |
1938 | /// #![feature(strict_overflow_ops)] |
1939 | #[doc = concat!("let _ = ", stringify!($SelfT), "::MAX.strict_pow(2);")] |
1940 | /// ``` |
1941 | #[unstable(feature = "strict_overflow_ops", issue = "118260")] |
1942 | #[must_use = "this returns the result of the operation, \ |
1943 | without modifying the original"] |
1944 | #[inline] |
1945 | #[track_caller] |
1946 | pub const fn strict_pow(self, mut exp: u32) -> Self { |
1947 | if exp == 0 { |
1948 | return 1; |
1949 | } |
1950 | let mut base = self; |
1951 | let mut acc: Self = 1; |
1952 | |
1953 | loop { |
1954 | if (exp & 1) == 1 { |
1955 | acc = acc.strict_mul(base); |
1956 | // since exp!=0, finally the exp must be 1. |
1957 | if exp == 1 { |
1958 | return acc; |
1959 | } |
1960 | } |
1961 | exp /= 2; |
1962 | base = base.strict_mul(base); |
1963 | } |
1964 | } |
1965 | |
1966 | /// Saturating integer addition. Computes `self + rhs`, saturating at |
1967 | /// the numeric bounds instead of overflowing. |
1968 | /// |
1969 | /// # Examples |
1970 | /// |
1971 | /// Basic usage: |
1972 | /// |
1973 | /// ``` |
1974 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_add(1), 101);")] |
1975 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_add(127), ", stringify!($SelfT), "::MAX);")] |
1976 | /// ``` |
1977 | #[stable(feature = "rust1", since = "1.0.0")] |
1978 | #[must_use = "this returns the result of the operation, \ |
1979 | without modifying the original"] |
1980 | #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] |
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 a signed integer. Computes `self + rhs`, |
1987 | /// saturating at the numeric bounds instead of overflowing. |
1988 | /// |
1989 | /// # Examples |
1990 | /// |
1991 | /// Basic usage: |
1992 | /// |
1993 | /// ``` |
1994 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(2), 3);")] |
1995 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_add_signed(-2), 0);")] |
1996 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_add_signed(4), ", stringify!($SelfT), "::MAX);")] |
1997 | /// ``` |
1998 | #[stable(feature = "mixed_integer_ops", since = "1.66.0")] |
1999 | #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")] |
2000 | #[must_use = "this returns the result of the operation, \ |
2001 | without modifying the original"] |
2002 | #[inline] |
2003 | pub const fn saturating_add_signed(self, rhs: $SignedT) -> Self { |
2004 | let (res, overflow) = self.overflowing_add(rhs as Self); |
2005 | if overflow == (rhs < 0) { |
2006 | res |
2007 | } else if overflow { |
2008 | Self::MAX |
2009 | } else { |
2010 | 0 |
2011 | } |
2012 | } |
2013 | |
2014 | /// Saturating integer subtraction. Computes `self - rhs`, saturating |
2015 | /// at the numeric bounds instead of overflowing. |
2016 | /// |
2017 | /// # Examples |
2018 | /// |
2019 | /// Basic usage: |
2020 | /// |
2021 | /// ``` |
2022 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".saturating_sub(27), 73);")] |
2023 | #[doc = concat!("assert_eq!(13", stringify!($SelfT), ".saturating_sub(127), 0);")] |
2024 | /// ``` |
2025 | #[stable(feature = "rust1", since = "1.0.0")] |
2026 | #[must_use = "this returns the result of the operation, \ |
2027 | without modifying the original"] |
2028 | #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] |
2029 | #[inline(always)] |
2030 | pub const fn saturating_sub(self, rhs: Self) -> Self { |
2031 | intrinsics::saturating_sub(self, rhs) |
2032 | } |
2033 | |
2034 | /// Saturating integer subtraction. Computes `self` - `rhs`, saturating at |
2035 | /// the numeric bounds instead of overflowing. |
2036 | /// |
2037 | /// # Examples |
2038 | /// |
2039 | /// Basic usage: |
2040 | /// |
2041 | /// ``` |
2042 | /// #![feature(mixed_integer_ops_unsigned_sub)] |
2043 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(2), 0);")] |
2044 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".saturating_sub_signed(-2), 3);")] |
2045 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).saturating_sub_signed(-4), ", stringify!($SelfT), "::MAX);")] |
2046 | /// ``` |
2047 | #[unstable(feature = "mixed_integer_ops_unsigned_sub", issue = "126043")] |
2048 | #[must_use = "this returns the result of the operation, \ |
2049 | without modifying the original"] |
2050 | #[inline] |
2051 | pub const fn saturating_sub_signed(self, rhs: $SignedT) -> Self { |
2052 | let (res, overflow) = self.overflowing_sub_signed(rhs); |
2053 | |
2054 | if !overflow { |
2055 | res |
2056 | } else if rhs < 0 { |
2057 | Self::MAX |
2058 | } else { |
2059 | 0 |
2060 | } |
2061 | } |
2062 | |
2063 | /// Saturating integer multiplication. Computes `self * rhs`, |
2064 | /// saturating at the numeric bounds instead of overflowing. |
2065 | /// |
2066 | /// # Examples |
2067 | /// |
2068 | /// Basic usage: |
2069 | /// |
2070 | /// ``` |
2071 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".saturating_mul(10), 20);")] |
2072 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX).saturating_mul(10), ", stringify!($SelfT), "::MAX);")] |
2073 | /// ``` |
2074 | #[stable(feature = "wrapping", since = "1.7.0")] |
2075 | #[rustc_const_stable(feature = "const_saturating_int_methods", since = "1.47.0")] |
2076 | #[must_use = "this returns the result of the operation, \ |
2077 | without modifying the original"] |
2078 | #[inline] |
2079 | pub const fn saturating_mul(self, rhs: Self) -> Self { |
2080 | match self.checked_mul(rhs) { |
2081 | Some(x) => x, |
2082 | None => Self::MAX, |
2083 | } |
2084 | } |
2085 | |
2086 | /// Saturating integer division. Computes `self / rhs`, saturating at the |
2087 | /// numeric bounds instead of overflowing. |
2088 | /// |
2089 | /// # Panics |
2090 | /// |
2091 | /// This function will panic if `rhs` is zero. |
2092 | /// |
2093 | /// # Examples |
2094 | /// |
2095 | /// Basic usage: |
2096 | /// |
2097 | /// ``` |
2098 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".saturating_div(2), 2);")] |
2099 | /// |
2100 | /// ``` |
2101 | #[stable(feature = "saturating_div", since = "1.58.0")] |
2102 | #[rustc_const_stable(feature = "saturating_div", since = "1.58.0")] |
2103 | #[must_use = "this returns the result of the operation, \ |
2104 | without modifying the original"] |
2105 | #[inline] |
2106 | #[track_caller] |
2107 | pub const fn saturating_div(self, rhs: Self) -> Self { |
2108 | // on unsigned types, there is no overflow in integer division |
2109 | self.wrapping_div(rhs) |
2110 | } |
2111 | |
2112 | /// Saturating integer exponentiation. Computes `self.pow(exp)`, |
2113 | /// saturating at the numeric bounds instead of overflowing. |
2114 | /// |
2115 | /// # Examples |
2116 | /// |
2117 | /// Basic usage: |
2118 | /// |
2119 | /// ``` |
2120 | #[doc = concat!("assert_eq!(4", stringify!($SelfT), ".saturating_pow(3), 64);")] |
2121 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT), "::MAX);")] |
2122 | /// ``` |
2123 | #[stable(feature = "no_panic_pow", since = "1.34.0")] |
2124 | #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] |
2125 | #[must_use = "this returns the result of the operation, \ |
2126 | without modifying the original"] |
2127 | #[inline] |
2128 | pub const fn saturating_pow(self, exp: u32) -> Self { |
2129 | match self.checked_pow(exp) { |
2130 | Some(x) => x, |
2131 | None => Self::MAX, |
2132 | } |
2133 | } |
2134 | |
2135 | /// Wrapping (modular) addition. Computes `self + rhs`, |
2136 | /// wrapping around at the boundary of the type. |
2137 | /// |
2138 | /// # Examples |
2139 | /// |
2140 | /// Basic usage: |
2141 | /// |
2142 | /// ``` |
2143 | #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(55), 255);")] |
2144 | #[doc = concat!("assert_eq!(200", stringify!($SelfT), ".wrapping_add(", stringify!($SelfT), "::MAX), 199);")] |
2145 | /// ``` |
2146 | #[stable(feature = "rust1", since = "1.0.0")] |
2147 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2148 | #[must_use = "this returns the result of the operation, \ |
2149 | without modifying the original"] |
2150 | #[inline(always)] |
2151 | pub const fn wrapping_add(self, rhs: Self) -> Self { |
2152 | intrinsics::wrapping_add(self, rhs) |
2153 | } |
2154 | |
2155 | /// Wrapping (modular) addition with a signed integer. Computes |
2156 | /// `self + rhs`, wrapping around at the boundary of the type. |
2157 | /// |
2158 | /// # Examples |
2159 | /// |
2160 | /// Basic usage: |
2161 | /// |
2162 | /// ``` |
2163 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(2), 3);")] |
2164 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_add_signed(-2), ", stringify!($SelfT), "::MAX);")] |
2165 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_add_signed(4), 1);")] |
2166 | /// ``` |
2167 | #[stable(feature = "mixed_integer_ops", since = "1.66.0")] |
2168 | #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")] |
2169 | #[must_use = "this returns the result of the operation, \ |
2170 | without modifying the original"] |
2171 | #[inline] |
2172 | pub const fn wrapping_add_signed(self, rhs: $SignedT) -> Self { |
2173 | self.wrapping_add(rhs as Self) |
2174 | } |
2175 | |
2176 | /// Wrapping (modular) subtraction. Computes `self - rhs`, |
2177 | /// wrapping around at the boundary of the type. |
2178 | /// |
2179 | /// # Examples |
2180 | /// |
2181 | /// Basic usage: |
2182 | /// |
2183 | /// ``` |
2184 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(100), 0);")] |
2185 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_sub(", stringify!($SelfT), "::MAX), 101);")] |
2186 | /// ``` |
2187 | #[stable(feature = "rust1", since = "1.0.0")] |
2188 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2189 | #[must_use = "this returns the result of the operation, \ |
2190 | without modifying the original"] |
2191 | #[inline(always)] |
2192 | pub const fn wrapping_sub(self, rhs: Self) -> Self { |
2193 | intrinsics::wrapping_sub(self, rhs) |
2194 | } |
2195 | |
2196 | /// Wrapping (modular) subtraction with a signed integer. Computes |
2197 | /// `self - rhs`, wrapping around at the boundary of the type. |
2198 | /// |
2199 | /// # Examples |
2200 | /// |
2201 | /// Basic usage: |
2202 | /// |
2203 | /// ``` |
2204 | /// #![feature(mixed_integer_ops_unsigned_sub)] |
2205 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(2), ", stringify!($SelfT), "::MAX);")] |
2206 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_sub_signed(-2), 3);")] |
2207 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).wrapping_sub_signed(-4), 1);")] |
2208 | /// ``` |
2209 | #[unstable(feature = "mixed_integer_ops_unsigned_sub", issue = "126043")] |
2210 | #[must_use = "this returns the result of the operation, \ |
2211 | without modifying the original"] |
2212 | #[inline] |
2213 | pub const fn wrapping_sub_signed(self, rhs: $SignedT) -> Self { |
2214 | self.wrapping_sub(rhs as Self) |
2215 | } |
2216 | |
2217 | /// Wrapping (modular) multiplication. Computes `self * |
2218 | /// rhs`, wrapping around at the boundary of the type. |
2219 | /// |
2220 | /// # Examples |
2221 | /// |
2222 | /// Basic usage: |
2223 | /// |
2224 | /// Please note that this example is shared between integer types. |
2225 | /// Which explains why `u8` is used here. |
2226 | /// |
2227 | /// ``` |
2228 | /// assert_eq!(10u8.wrapping_mul(12), 120); |
2229 | /// assert_eq!(25u8.wrapping_mul(12), 44); |
2230 | /// ``` |
2231 | #[stable(feature = "rust1", since = "1.0.0")] |
2232 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2233 | #[must_use = "this returns the result of the operation, \ |
2234 | without modifying the original"] |
2235 | #[inline(always)] |
2236 | pub const fn wrapping_mul(self, rhs: Self) -> Self { |
2237 | intrinsics::wrapping_mul(self, rhs) |
2238 | } |
2239 | |
2240 | /// Wrapping (modular) division. Computes `self / rhs`. |
2241 | /// |
2242 | /// Wrapped division on unsigned types is just normal division. There's |
2243 | /// no way wrapping could ever happen. This function exists so that all |
2244 | /// operations are accounted for in the wrapping operations. |
2245 | /// |
2246 | /// # Panics |
2247 | /// |
2248 | /// This function will panic if `rhs` is zero. |
2249 | /// |
2250 | /// # Examples |
2251 | /// |
2252 | /// Basic usage: |
2253 | /// |
2254 | /// ``` |
2255 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div(10), 10);")] |
2256 | /// ``` |
2257 | #[stable(feature = "num_wrapping", since = "1.2.0")] |
2258 | #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")] |
2259 | #[must_use = "this returns the result of the operation, \ |
2260 | without modifying the original"] |
2261 | #[inline(always)] |
2262 | #[track_caller] |
2263 | pub const fn wrapping_div(self, rhs: Self) -> Self { |
2264 | self / rhs |
2265 | } |
2266 | |
2267 | /// Wrapping Euclidean division. Computes `self.div_euclid(rhs)`. |
2268 | /// |
2269 | /// Wrapped division on unsigned types is just normal division. There's |
2270 | /// no way wrapping could ever happen. This function exists so that all |
2271 | /// operations are accounted for in the wrapping operations. Since, for |
2272 | /// the positive integers, all common definitions of division are equal, |
2273 | /// this is exactly equal to `self.wrapping_div(rhs)`. |
2274 | /// |
2275 | /// # Panics |
2276 | /// |
2277 | /// This function will panic if `rhs` is zero. |
2278 | /// |
2279 | /// # Examples |
2280 | /// |
2281 | /// Basic usage: |
2282 | /// |
2283 | /// ``` |
2284 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_div_euclid(10), 10);")] |
2285 | /// ``` |
2286 | #[stable(feature = "euclidean_division", since = "1.38.0")] |
2287 | #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] |
2288 | #[must_use = "this returns the result of the operation, \ |
2289 | without modifying the original"] |
2290 | #[inline(always)] |
2291 | #[track_caller] |
2292 | pub const fn wrapping_div_euclid(self, rhs: Self) -> Self { |
2293 | self / rhs |
2294 | } |
2295 | |
2296 | /// Wrapping (modular) remainder. Computes `self % rhs`. |
2297 | /// |
2298 | /// Wrapped remainder calculation on unsigned types is just the regular |
2299 | /// remainder calculation. There's no way wrapping could ever happen. |
2300 | /// This function exists so that all operations are accounted for in the |
2301 | /// wrapping operations. |
2302 | /// |
2303 | /// # Panics |
2304 | /// |
2305 | /// This function will panic if `rhs` is zero. |
2306 | /// |
2307 | /// # Examples |
2308 | /// |
2309 | /// Basic usage: |
2310 | /// |
2311 | /// ``` |
2312 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem(10), 0);")] |
2313 | /// ``` |
2314 | #[stable(feature = "num_wrapping", since = "1.2.0")] |
2315 | #[rustc_const_stable(feature = "const_wrapping_int_methods", since = "1.52.0")] |
2316 | #[must_use = "this returns the result of the operation, \ |
2317 | without modifying the original"] |
2318 | #[inline(always)] |
2319 | #[track_caller] |
2320 | pub const fn wrapping_rem(self, rhs: Self) -> Self { |
2321 | self % rhs |
2322 | } |
2323 | |
2324 | /// Wrapping Euclidean modulo. Computes `self.rem_euclid(rhs)`. |
2325 | /// |
2326 | /// Wrapped modulo calculation on unsigned types is just the regular |
2327 | /// remainder calculation. There's no way wrapping could ever happen. |
2328 | /// This function exists so that all operations are accounted for in the |
2329 | /// wrapping operations. Since, for the positive integers, all common |
2330 | /// definitions of division are equal, this is exactly equal to |
2331 | /// `self.wrapping_rem(rhs)`. |
2332 | /// |
2333 | /// # Panics |
2334 | /// |
2335 | /// This function will panic if `rhs` is zero. |
2336 | /// |
2337 | /// # Examples |
2338 | /// |
2339 | /// Basic usage: |
2340 | /// |
2341 | /// ``` |
2342 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);")] |
2343 | /// ``` |
2344 | #[stable(feature = "euclidean_division", since = "1.38.0")] |
2345 | #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] |
2346 | #[must_use = "this returns the result of the operation, \ |
2347 | without modifying the original"] |
2348 | #[inline(always)] |
2349 | #[track_caller] |
2350 | pub const fn wrapping_rem_euclid(self, rhs: Self) -> Self { |
2351 | self % rhs |
2352 | } |
2353 | |
2354 | /// Wrapping (modular) negation. Computes `-self`, |
2355 | /// wrapping around at the boundary of the type. |
2356 | /// |
2357 | /// Since unsigned types do not have negative equivalents |
2358 | /// all applications of this function will wrap (except for `-0`). |
2359 | /// For values smaller than the corresponding signed type's maximum |
2360 | /// the result is the same as casting the corresponding signed value. |
2361 | /// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where |
2362 | /// `MAX` is the corresponding signed type's maximum. |
2363 | /// |
2364 | /// # Examples |
2365 | /// |
2366 | /// Basic usage: |
2367 | /// |
2368 | /// ``` |
2369 | #[doc = concat!("assert_eq!(0_", stringify!($SelfT), ".wrapping_neg(), 0);")] |
2370 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_neg(), 1);")] |
2371 | #[doc = concat!("assert_eq!(13_", stringify!($SelfT), ".wrapping_neg(), (!13) + 1);")] |
2372 | #[doc = concat!("assert_eq!(42_", stringify!($SelfT), ".wrapping_neg(), !(42 - 1));")] |
2373 | /// ``` |
2374 | #[stable(feature = "num_wrapping", since = "1.2.0")] |
2375 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2376 | #[must_use = "this returns the result of the operation, \ |
2377 | without modifying the original"] |
2378 | #[inline(always)] |
2379 | pub const fn wrapping_neg(self) -> Self { |
2380 | (0 as $SelfT).wrapping_sub(self) |
2381 | } |
2382 | |
2383 | /// Panic-free bitwise shift-left; yields `self << mask(rhs)`, |
2384 | /// where `mask` removes any high-order bits of `rhs` that |
2385 | /// would cause the shift to exceed the bitwidth of the type. |
2386 | /// |
2387 | /// Note that this is *not* the same as a rotate-left; the |
2388 | /// RHS of a wrapping shift-left is restricted to the range |
2389 | /// of the type, rather than the bits shifted out of the LHS |
2390 | /// being returned to the other end. The primitive integer |
2391 | /// types all implement a [`rotate_left`](Self::rotate_left) function, |
2392 | /// which may be what you want instead. |
2393 | /// |
2394 | /// # Examples |
2395 | /// |
2396 | /// Basic usage: |
2397 | /// |
2398 | /// ``` |
2399 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(7), 128);")] |
2400 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".wrapping_shl(128), 1);")] |
2401 | /// ``` |
2402 | #[stable(feature = "num_wrapping", since = "1.2.0")] |
2403 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2404 | #[must_use = "this returns the result of the operation, \ |
2405 | without modifying the original"] |
2406 | #[inline(always)] |
2407 | pub const fn wrapping_shl(self, rhs: u32) -> Self { |
2408 | // SAFETY: the masking by the bitsize of the type ensures that we do not shift |
2409 | // out of bounds |
2410 | unsafe { |
2411 | self.unchecked_shl(rhs & (Self::BITS - 1)) |
2412 | } |
2413 | } |
2414 | |
2415 | /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`, |
2416 | /// where `mask` removes any high-order bits of `rhs` that |
2417 | /// would cause the shift to exceed the bitwidth of the type. |
2418 | /// |
2419 | /// Note that this is *not* the same as a rotate-right; the |
2420 | /// RHS of a wrapping shift-right is restricted to the range |
2421 | /// of the type, rather than the bits shifted out of the LHS |
2422 | /// being returned to the other end. The primitive integer |
2423 | /// types all implement a [`rotate_right`](Self::rotate_right) function, |
2424 | /// which may be what you want instead. |
2425 | /// |
2426 | /// # Examples |
2427 | /// |
2428 | /// Basic usage: |
2429 | /// |
2430 | /// ``` |
2431 | #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(7), 1);")] |
2432 | #[doc = concat!("assert_eq!(128", stringify!($SelfT), ".wrapping_shr(128), 128);")] |
2433 | /// ``` |
2434 | #[stable(feature = "num_wrapping", since = "1.2.0")] |
2435 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2436 | #[must_use = "this returns the result of the operation, \ |
2437 | without modifying the original"] |
2438 | #[inline(always)] |
2439 | pub const fn wrapping_shr(self, rhs: u32) -> Self { |
2440 | // SAFETY: the masking by the bitsize of the type ensures that we do not shift |
2441 | // out of bounds |
2442 | unsafe { |
2443 | self.unchecked_shr(rhs & (Self::BITS - 1)) |
2444 | } |
2445 | } |
2446 | |
2447 | /// Wrapping (modular) exponentiation. Computes `self.pow(exp)`, |
2448 | /// wrapping around at the boundary of the type. |
2449 | /// |
2450 | /// # Examples |
2451 | /// |
2452 | /// Basic usage: |
2453 | /// |
2454 | /// ``` |
2455 | #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_pow(5), 243);")] |
2456 | /// assert_eq!(3u8.wrapping_pow(6), 217); |
2457 | /// ``` |
2458 | #[stable(feature = "no_panic_pow", since = "1.34.0")] |
2459 | #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] |
2460 | #[must_use = "this returns the result of the operation, \ |
2461 | without modifying the original"] |
2462 | #[inline] |
2463 | pub const fn wrapping_pow(self, mut exp: u32) -> Self { |
2464 | if exp == 0 { |
2465 | return 1; |
2466 | } |
2467 | let mut base = self; |
2468 | let mut acc: Self = 1; |
2469 | |
2470 | if intrinsics::is_val_statically_known(exp) { |
2471 | while exp > 1 { |
2472 | if (exp & 1) == 1 { |
2473 | acc = acc.wrapping_mul(base); |
2474 | } |
2475 | exp /= 2; |
2476 | base = base.wrapping_mul(base); |
2477 | } |
2478 | |
2479 | // since exp!=0, finally the exp must be 1. |
2480 | // Deal with the final bit of the exponent separately, since |
2481 | // squaring the base afterwards is not necessary. |
2482 | acc.wrapping_mul(base) |
2483 | } else { |
2484 | // This is faster than the above when the exponent is not known |
2485 | // at compile time. We can't use the same code for the constant |
2486 | // exponent case because LLVM is currently unable to unroll |
2487 | // this loop. |
2488 | loop { |
2489 | if (exp & 1) == 1 { |
2490 | acc = acc.wrapping_mul(base); |
2491 | // since exp!=0, finally the exp must be 1. |
2492 | if exp == 1 { |
2493 | return acc; |
2494 | } |
2495 | } |
2496 | exp /= 2; |
2497 | base = base.wrapping_mul(base); |
2498 | } |
2499 | } |
2500 | } |
2501 | |
2502 | /// Calculates `self` + `rhs`. |
2503 | /// |
2504 | /// Returns a tuple of the addition along with a boolean indicating |
2505 | /// whether an arithmetic overflow would occur. If an overflow would |
2506 | /// have occurred then the wrapped value is returned. |
2507 | /// |
2508 | /// # Examples |
2509 | /// |
2510 | /// Basic usage: |
2511 | /// |
2512 | /// ``` |
2513 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_add(2), (7, false));")] |
2514 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.overflowing_add(1), (0, true));")] |
2515 | /// ``` |
2516 | #[stable(feature = "wrapping", since = "1.7.0")] |
2517 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2518 | #[must_use = "this returns the result of the operation, \ |
2519 | without modifying the original"] |
2520 | #[inline(always)] |
2521 | pub const fn overflowing_add(self, rhs: Self) -> (Self, bool) { |
2522 | let (a, b) = intrinsics::add_with_overflow(self as $ActualT, rhs as $ActualT); |
2523 | (a as Self, b) |
2524 | } |
2525 | |
2526 | /// Calculates `self` + `rhs` + `carry` and returns a tuple containing |
2527 | /// the sum and the output carry. |
2528 | /// |
2529 | /// Performs "ternary addition" of two integer operands and a carry-in |
2530 | /// bit, and returns an output integer and a carry-out bit. This allows |
2531 | /// chaining together multiple additions to create a wider addition, and |
2532 | /// can be useful for bignum addition. |
2533 | /// |
2534 | #[doc = concat!("This can be thought of as a ", stringify!($BITS), "-bit\" full adder\" , in the electronics sense.")] |
2535 | /// |
2536 | /// If the input carry is false, this method is equivalent to |
2537 | /// [`overflowing_add`](Self::overflowing_add), and the output carry is |
2538 | /// equal to the overflow flag. Note that although carry and overflow |
2539 | /// flags are similar for unsigned integers, they are different for |
2540 | /// signed integers. |
2541 | /// |
2542 | /// # Examples |
2543 | /// |
2544 | /// ``` |
2545 | /// #![feature(bigint_helper_methods)] |
2546 | /// |
2547 | #[doc = concat!("// 3 MAX (a = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")] |
2548 | #[doc = concat!("// + 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")] |
2549 | /// // --------- |
2550 | #[doc = concat!("// 9 6 (sum = 9 × 2^", stringify!($BITS), " + 6)")] |
2551 | /// |
2552 | #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (3, ", stringify!($SelfT), "::MAX);")] |
2553 | #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")] |
2554 | /// let carry0 = false; |
2555 | /// |
2556 | /// let (sum0, carry1) = a0.carrying_add(b0, carry0); |
2557 | /// assert_eq!(carry1, true); |
2558 | /// let (sum1, carry2) = a1.carrying_add(b1, carry1); |
2559 | /// assert_eq!(carry2, false); |
2560 | /// |
2561 | /// assert_eq!((sum1, sum0), (9, 6)); |
2562 | /// ``` |
2563 | #[unstable(feature = "bigint_helper_methods", issue = "85532")] |
2564 | #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")] |
2565 | #[must_use = "this returns the result of the operation, \ |
2566 | without modifying the original"] |
2567 | #[inline] |
2568 | pub const fn carrying_add(self, rhs: Self, carry: bool) -> (Self, bool) { |
2569 | // note: longer-term this should be done via an intrinsic, but this has been shown |
2570 | // to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic |
2571 | let (a, c1) = self.overflowing_add(rhs); |
2572 | let (b, c2) = a.overflowing_add(carry as $SelfT); |
2573 | // Ideally LLVM would know this is disjoint without us telling them, |
2574 | // but it doesn't <https://github.com/llvm/llvm-project/issues/118162> |
2575 | // SAFETY: Only one of `c1` and `c2` can be set. |
2576 | // For c1 to be set we need to have overflowed, but if we did then |
2577 | // `a` is at most `MAX-1`, which means that `c2` cannot possibly |
2578 | // overflow because it's adding at most `1` (since it came from `bool`) |
2579 | (b, unsafe { intrinsics::disjoint_bitor(c1, c2) }) |
2580 | } |
2581 | |
2582 | /// Calculates `self` + `rhs` with a signed `rhs`. |
2583 | /// |
2584 | /// Returns a tuple of the addition along with a boolean indicating |
2585 | /// whether an arithmetic overflow would occur. If an overflow would |
2586 | /// have occurred then the wrapped value is returned. |
2587 | /// |
2588 | /// # Examples |
2589 | /// |
2590 | /// Basic usage: |
2591 | /// |
2592 | /// ``` |
2593 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(2), (3, false));")] |
2594 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_add_signed(-2), (", stringify!($SelfT), "::MAX, true));")] |
2595 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_add_signed(4), (1, true));")] |
2596 | /// ``` |
2597 | #[stable(feature = "mixed_integer_ops", since = "1.66.0")] |
2598 | #[rustc_const_stable(feature = "mixed_integer_ops", since = "1.66.0")] |
2599 | #[must_use = "this returns the result of the operation, \ |
2600 | without modifying the original"] |
2601 | #[inline] |
2602 | pub const fn overflowing_add_signed(self, rhs: $SignedT) -> (Self, bool) { |
2603 | let (res, overflowed) = self.overflowing_add(rhs as Self); |
2604 | (res, overflowed ^ (rhs < 0)) |
2605 | } |
2606 | |
2607 | /// Calculates `self` - `rhs`. |
2608 | /// |
2609 | /// Returns a tuple of the subtraction along with a boolean indicating |
2610 | /// whether an arithmetic overflow would occur. If an overflow would |
2611 | /// have occurred then the wrapped value is returned. |
2612 | /// |
2613 | /// # Examples |
2614 | /// |
2615 | /// Basic usage: |
2616 | /// |
2617 | /// ``` |
2618 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_sub(2), (3, false));")] |
2619 | #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_sub(1), (", stringify!($SelfT), "::MAX, true));")] |
2620 | /// ``` |
2621 | #[stable(feature = "wrapping", since = "1.7.0")] |
2622 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2623 | #[must_use = "this returns the result of the operation, \ |
2624 | without modifying the original"] |
2625 | #[inline(always)] |
2626 | pub const fn overflowing_sub(self, rhs: Self) -> (Self, bool) { |
2627 | let (a, b) = intrinsics::sub_with_overflow(self as $ActualT, rhs as $ActualT); |
2628 | (a as Self, b) |
2629 | } |
2630 | |
2631 | /// Calculates `self` − `rhs` − `borrow` and returns a tuple |
2632 | /// containing the difference and the output borrow. |
2633 | /// |
2634 | /// Performs "ternary subtraction" by subtracting both an integer |
2635 | /// operand and a borrow-in bit from `self`, and returns an output |
2636 | /// integer and a borrow-out bit. This allows chaining together multiple |
2637 | /// subtractions to create a wider subtraction, and can be useful for |
2638 | /// bignum subtraction. |
2639 | /// |
2640 | /// # Examples |
2641 | /// |
2642 | /// ``` |
2643 | /// #![feature(bigint_helper_methods)] |
2644 | /// |
2645 | #[doc = concat!("// 9 6 (a = 9 × 2^", stringify!($BITS), " + 6)")] |
2646 | #[doc = concat!("// - 5 7 (b = 5 × 2^", stringify!($BITS), " + 7)")] |
2647 | /// // --------- |
2648 | #[doc = concat!("// 3 MAX (diff = 3 × 2^", stringify!($BITS), " + 2^", stringify!($BITS), " - 1)")] |
2649 | /// |
2650 | #[doc = concat!("let (a1, a0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (9, 6);")] |
2651 | #[doc = concat!("let (b1, b0): (", stringify!($SelfT), ", ", stringify!($SelfT), ") = (5, 7);")] |
2652 | /// let borrow0 = false; |
2653 | /// |
2654 | /// let (diff0, borrow1) = a0.borrowing_sub(b0, borrow0); |
2655 | /// assert_eq!(borrow1, true); |
2656 | /// let (diff1, borrow2) = a1.borrowing_sub(b1, borrow1); |
2657 | /// assert_eq!(borrow2, false); |
2658 | /// |
2659 | #[doc = concat!("assert_eq!((diff1, diff0), (3, ", stringify!($SelfT), "::MAX));")] |
2660 | /// ``` |
2661 | #[unstable(feature = "bigint_helper_methods", issue = "85532")] |
2662 | #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")] |
2663 | #[must_use = "this returns the result of the operation, \ |
2664 | without modifying the original"] |
2665 | #[inline] |
2666 | pub const fn borrowing_sub(self, rhs: Self, borrow: bool) -> (Self, bool) { |
2667 | // note: longer-term this should be done via an intrinsic, but this has been shown |
2668 | // to generate optimal code for now, and LLVM doesn't have an equivalent intrinsic |
2669 | let (a, c1) = self.overflowing_sub(rhs); |
2670 | let (b, c2) = a.overflowing_sub(borrow as $SelfT); |
2671 | // SAFETY: Only one of `c1` and `c2` can be set. |
2672 | // For c1 to be set we need to have underflowed, but if we did then |
2673 | // `a` is nonzero, which means that `c2` cannot possibly |
2674 | // underflow because it's subtracting at most `1` (since it came from `bool`) |
2675 | (b, unsafe { intrinsics::disjoint_bitor(c1, c2) }) |
2676 | } |
2677 | |
2678 | /// Calculates `self` - `rhs` with a signed `rhs` |
2679 | /// |
2680 | /// Returns a tuple of the subtraction along with a boolean indicating |
2681 | /// whether an arithmetic overflow would occur. If an overflow would |
2682 | /// have occurred then the wrapped value is returned. |
2683 | /// |
2684 | /// # Examples |
2685 | /// |
2686 | /// Basic usage: |
2687 | /// |
2688 | /// ``` |
2689 | /// #![feature(mixed_integer_ops_unsigned_sub)] |
2690 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(2), (", stringify!($SelfT), "::MAX, true));")] |
2691 | #[doc = concat!("assert_eq!(1", stringify!($SelfT), ".overflowing_sub_signed(-2), (3, false));")] |
2692 | #[doc = concat!("assert_eq!((", stringify!($SelfT), "::MAX - 2).overflowing_sub_signed(-4), (1, true));")] |
2693 | /// ``` |
2694 | #[unstable(feature = "mixed_integer_ops_unsigned_sub", issue = "126043")] |
2695 | #[must_use = "this returns the result of the operation, \ |
2696 | without modifying the original"] |
2697 | #[inline] |
2698 | pub const fn overflowing_sub_signed(self, rhs: $SignedT) -> (Self, bool) { |
2699 | let (res, overflow) = self.overflowing_sub(rhs as Self); |
2700 | |
2701 | (res, overflow ^ (rhs < 0)) |
2702 | } |
2703 | |
2704 | /// Computes the absolute difference between `self` and `other`. |
2705 | /// |
2706 | /// # Examples |
2707 | /// |
2708 | /// Basic usage: |
2709 | /// |
2710 | /// ``` |
2711 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(80), 20", stringify!($SelfT), ");")] |
2712 | #[doc = concat!("assert_eq!(100", stringify!($SelfT), ".abs_diff(110), 10", stringify!($SelfT), ");")] |
2713 | /// ``` |
2714 | #[stable(feature = "int_abs_diff", since = "1.60.0")] |
2715 | #[rustc_const_stable(feature = "int_abs_diff", since = "1.60.0")] |
2716 | #[must_use = "this returns the result of the operation, \ |
2717 | without modifying the original"] |
2718 | #[inline] |
2719 | pub const fn abs_diff(self, other: Self) -> Self { |
2720 | if size_of::<Self>() == 1 { |
2721 | // Trick LLVM into generating the psadbw instruction when SSE2 |
2722 | // is available and this function is autovectorized for u8's. |
2723 | (self as i32).wrapping_sub(other as i32).abs() as Self |
2724 | } else { |
2725 | if self < other { |
2726 | other - self |
2727 | } else { |
2728 | self - other |
2729 | } |
2730 | } |
2731 | } |
2732 | |
2733 | /// Calculates the multiplication of `self` and `rhs`. |
2734 | /// |
2735 | /// Returns a tuple of the multiplication along with a boolean |
2736 | /// indicating whether an arithmetic overflow would occur. If an |
2737 | /// overflow would have occurred then the wrapped value is returned. |
2738 | /// |
2739 | /// # Examples |
2740 | /// |
2741 | /// Basic usage: |
2742 | /// |
2743 | /// Please note that this example is shared between integer types. |
2744 | /// Which explains why `u32` is used here. |
2745 | /// |
2746 | /// ``` |
2747 | /// assert_eq!(5u32.overflowing_mul(2), (10, false)); |
2748 | /// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true)); |
2749 | /// ``` |
2750 | #[stable(feature = "wrapping", since = "1.7.0")] |
2751 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
2752 | #[must_use = "this returns the result of the operation, \ |
2753 | without modifying the original"] |
2754 | #[inline(always)] |
2755 | pub const fn overflowing_mul(self, rhs: Self) -> (Self, bool) { |
2756 | let (a, b) = intrinsics::mul_with_overflow(self as $ActualT, rhs as $ActualT); |
2757 | (a as Self, b) |
2758 | } |
2759 | |
2760 | /// Calculates the complete product `self * rhs` without the possibility to overflow. |
2761 | /// |
2762 | /// This returns the low-order (wrapping) bits and the high-order (overflow) bits |
2763 | /// of the result as two separate values, in that order. |
2764 | /// |
2765 | /// If you also need to add a carry to the wide result, then you want |
2766 | /// [`Self::carrying_mul`] instead. |
2767 | /// |
2768 | /// # Examples |
2769 | /// |
2770 | /// Basic usage: |
2771 | /// |
2772 | /// Please note that this example is shared between integer types. |
2773 | /// Which explains why `u32` is used here. |
2774 | /// |
2775 | /// ``` |
2776 | /// #![feature(bigint_helper_methods)] |
2777 | /// assert_eq!(5u32.widening_mul(2), (10, 0)); |
2778 | /// assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2)); |
2779 | /// ``` |
2780 | #[unstable(feature = "bigint_helper_methods", issue = "85532")] |
2781 | #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")] |
2782 | #[must_use = "this returns the result of the operation, \ |
2783 | without modifying the original"] |
2784 | #[inline] |
2785 | pub const fn widening_mul(self, rhs: Self) -> (Self, Self) { |
2786 | Self::carrying_mul_add(self, rhs, 0, 0) |
2787 | } |
2788 | |
2789 | /// Calculates the "full multiplication" `self * rhs + carry` |
2790 | /// without the possibility to overflow. |
2791 | /// |
2792 | /// This returns the low-order (wrapping) bits and the high-order (overflow) bits |
2793 | /// of the result as two separate values, in that order. |
2794 | /// |
2795 | /// Performs "long multiplication" which takes in an extra amount to add, and may return an |
2796 | /// additional amount of overflow. This allows for chaining together multiple |
2797 | /// multiplications to create "big integers" which represent larger values. |
2798 | /// |
2799 | /// If you don't need the `carry`, then you can use [`Self::widening_mul`] instead. |
2800 | /// |
2801 | /// # Examples |
2802 | /// |
2803 | /// Basic usage: |
2804 | /// |
2805 | /// Please note that this example is shared between integer types. |
2806 | /// Which explains why `u32` is used here. |
2807 | /// |
2808 | /// ``` |
2809 | /// #![feature(bigint_helper_methods)] |
2810 | /// assert_eq!(5u32.carrying_mul(2, 0), (10, 0)); |
2811 | /// assert_eq!(5u32.carrying_mul(2, 10), (20, 0)); |
2812 | /// assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2)); |
2813 | /// assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2)); |
2814 | #[doc = concat!("assert_eq!(", |
2815 | stringify!($SelfT), "::MAX.carrying_mul(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ", |
2816 | "(0, ", stringify!($SelfT), "::MAX));" |
2817 | )] |
2818 | /// ``` |
2819 | /// |
2820 | /// This is the core operation needed for scalar multiplication when |
2821 | /// implementing it for wider-than-native types. |
2822 | /// |
2823 | /// ``` |
2824 | /// #![feature(bigint_helper_methods)] |
2825 | /// fn scalar_mul_eq(little_endian_digits: &mut Vec<u16>, multiplicand: u16) { |
2826 | /// let mut carry = 0; |
2827 | /// for d in little_endian_digits.iter_mut() { |
2828 | /// (*d, carry) = d.carrying_mul(multiplicand, carry); |
2829 | /// } |
2830 | /// if carry != 0 { |
2831 | /// little_endian_digits.push(carry); |
2832 | /// } |
2833 | /// } |
2834 | /// |
2835 | /// let mut v = vec![10, 20]; |
2836 | /// scalar_mul_eq(&mut v, 3); |
2837 | /// assert_eq!(v, [30, 60]); |
2838 | /// |
2839 | /// assert_eq!(0x87654321_u64 * 0xFEED, 0x86D3D159E38D); |
2840 | /// let mut v = vec![0x4321, 0x8765]; |
2841 | /// scalar_mul_eq(&mut v, 0xFEED); |
2842 | /// assert_eq!(v, [0xE38D, 0xD159, 0x86D3]); |
2843 | /// ``` |
2844 | /// |
2845 | /// If `carry` is zero, this is similar to [`overflowing_mul`](Self::overflowing_mul), |
2846 | /// except that it gives the value of the overflow instead of just whether one happened: |
2847 | /// |
2848 | /// ``` |
2849 | /// #![feature(bigint_helper_methods)] |
2850 | /// let r = u8::carrying_mul(7, 13, 0); |
2851 | /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(7, 13)); |
2852 | /// let r = u8::carrying_mul(13, 42, 0); |
2853 | /// assert_eq!((r.0, r.1 != 0), u8::overflowing_mul(13, 42)); |
2854 | /// ``` |
2855 | /// |
2856 | /// The value of the first field in the returned tuple matches what you'd get |
2857 | /// by combining the [`wrapping_mul`](Self::wrapping_mul) and |
2858 | /// [`wrapping_add`](Self::wrapping_add) methods: |
2859 | /// |
2860 | /// ``` |
2861 | /// #![feature(bigint_helper_methods)] |
2862 | /// assert_eq!( |
2863 | /// 789_u16.carrying_mul(456, 123).0, |
2864 | /// 789_u16.wrapping_mul(456).wrapping_add(123), |
2865 | /// ); |
2866 | /// ``` |
2867 | #[unstable(feature = "bigint_helper_methods", issue = "85532")] |
2868 | #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")] |
2869 | #[must_use = "this returns the result of the operation, \ |
2870 | without modifying the original"] |
2871 | #[inline] |
2872 | pub const fn carrying_mul(self, rhs: Self, carry: Self) -> (Self, Self) { |
2873 | Self::carrying_mul_add(self, rhs, carry, 0) |
2874 | } |
2875 | |
2876 | /// Calculates the "full multiplication" `self * rhs + carry1 + carry2` |
2877 | /// without the possibility to overflow. |
2878 | /// |
2879 | /// This returns the low-order (wrapping) bits and the high-order (overflow) bits |
2880 | /// of the result as two separate values, in that order. |
2881 | /// |
2882 | /// Performs "long multiplication" which takes in an extra amount to add, and may return an |
2883 | /// additional amount of overflow. This allows for chaining together multiple |
2884 | /// multiplications to create "big integers" which represent larger values. |
2885 | /// |
2886 | /// If you don't need either `carry`, then you can use [`Self::widening_mul`] instead, |
2887 | /// and if you only need one `carry`, then you can use [`Self::carrying_mul`] instead. |
2888 | /// |
2889 | /// # Examples |
2890 | /// |
2891 | /// Basic usage: |
2892 | /// |
2893 | /// Please note that this example is shared between integer types, |
2894 | /// which explains why `u32` is used here. |
2895 | /// |
2896 | /// ``` |
2897 | /// #![feature(bigint_helper_methods)] |
2898 | /// assert_eq!(5u32.carrying_mul_add(2, 0, 0), (10, 0)); |
2899 | /// assert_eq!(5u32.carrying_mul_add(2, 10, 10), (30, 0)); |
2900 | /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 0, 0), (1410065408, 2)); |
2901 | /// assert_eq!(1_000_000_000u32.carrying_mul_add(10, 10, 10), (1410065428, 2)); |
2902 | #[doc = concat!("assert_eq!(", |
2903 | stringify!($SelfT), "::MAX.carrying_mul_add(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX), ", |
2904 | "(", stringify!($SelfT), "::MAX, ", stringify!($SelfT), "::MAX));" |
2905 | )] |
2906 | /// ``` |
2907 | /// |
2908 | /// This is the core per-digit operation for "grade school" O(n²) multiplication. |
2909 | /// |
2910 | /// Please note that this example is shared between integer types, |
2911 | /// using `u8` for simplicity of the demonstration. |
2912 | /// |
2913 | /// ``` |
2914 | /// #![feature(bigint_helper_methods)] |
2915 | /// |
2916 | /// fn quadratic_mul<const N: usize>(a: [u8; N], b: [u8; N]) -> [u8; N] { |
2917 | /// let mut out = [0; N]; |
2918 | /// for j in 0..N { |
2919 | /// let mut carry = 0; |
2920 | /// for i in 0..(N - j) { |
2921 | /// (out[j + i], carry) = u8::carrying_mul_add(a[i], b[j], out[j + i], carry); |
2922 | /// } |
2923 | /// } |
2924 | /// out |
2925 | /// } |
2926 | /// |
2927 | /// // -1 * -1 == 1 |
2928 | /// assert_eq!(quadratic_mul([0xFF; 3], [0xFF; 3]), [1, 0, 0]); |
2929 | /// |
2930 | /// assert_eq!(u32::wrapping_mul(0x9e3779b9, 0x7f4a7c15), 0xCFFC982D); |
2931 | /// assert_eq!( |
2932 | /// quadratic_mul(u32::to_le_bytes(0x9e3779b9), u32::to_le_bytes(0x7f4a7c15)), |
2933 | /// u32::to_le_bytes(0xCFFC982D) |
2934 | /// ); |
2935 | /// ``` |
2936 | #[unstable(feature = "bigint_helper_methods", issue = "85532")] |
2937 | #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")] |
2938 | #[must_use = "this returns the result of the operation, \ |
2939 | without modifying the original"] |
2940 | #[inline] |
2941 | pub const fn carrying_mul_add(self, rhs: Self, carry: Self, add: Self) -> (Self, Self) { |
2942 | intrinsics::carrying_mul_add(self, rhs, carry, add) |
2943 | } |
2944 | |
2945 | /// Calculates the divisor when `self` is divided by `rhs`. |
2946 | /// |
2947 | /// Returns a tuple of the divisor along with a boolean indicating |
2948 | /// whether an arithmetic overflow would occur. Note that for unsigned |
2949 | /// integers overflow never occurs, so the second value is always |
2950 | /// `false`. |
2951 | /// |
2952 | /// # Panics |
2953 | /// |
2954 | /// This function will panic if `rhs` is zero. |
2955 | /// |
2956 | /// # Examples |
2957 | /// |
2958 | /// Basic usage: |
2959 | /// |
2960 | /// ``` |
2961 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div(2), (2, false));")] |
2962 | /// ``` |
2963 | #[inline(always)] |
2964 | #[stable(feature = "wrapping", since = "1.7.0")] |
2965 | #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")] |
2966 | #[must_use = "this returns the result of the operation, \ |
2967 | without modifying the original"] |
2968 | #[track_caller] |
2969 | pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) { |
2970 | (self / rhs, false) |
2971 | } |
2972 | |
2973 | /// Calculates the quotient of Euclidean division `self.div_euclid(rhs)`. |
2974 | /// |
2975 | /// Returns a tuple of the divisor along with a boolean indicating |
2976 | /// whether an arithmetic overflow would occur. Note that for unsigned |
2977 | /// integers overflow never occurs, so the second value is always |
2978 | /// `false`. |
2979 | /// Since, for the positive integers, all common |
2980 | /// definitions of division are equal, this |
2981 | /// is exactly equal to `self.overflowing_div(rhs)`. |
2982 | /// |
2983 | /// # Panics |
2984 | /// |
2985 | /// This function will panic if `rhs` is zero. |
2986 | /// |
2987 | /// # Examples |
2988 | /// |
2989 | /// Basic usage: |
2990 | /// |
2991 | /// ``` |
2992 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_div_euclid(2), (2, false));")] |
2993 | /// ``` |
2994 | #[inline(always)] |
2995 | #[stable(feature = "euclidean_division", since = "1.38.0")] |
2996 | #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] |
2997 | #[must_use = "this returns the result of the operation, \ |
2998 | without modifying the original"] |
2999 | #[track_caller] |
3000 | pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) { |
3001 | (self / rhs, false) |
3002 | } |
3003 | |
3004 | /// Calculates the remainder when `self` is divided by `rhs`. |
3005 | /// |
3006 | /// Returns a tuple of the remainder after dividing along with a boolean |
3007 | /// indicating whether an arithmetic overflow would occur. Note that for |
3008 | /// unsigned integers overflow never occurs, so the second value is |
3009 | /// always `false`. |
3010 | /// |
3011 | /// # Panics |
3012 | /// |
3013 | /// This function will panic if `rhs` is zero. |
3014 | /// |
3015 | /// # Examples |
3016 | /// |
3017 | /// Basic usage: |
3018 | /// |
3019 | /// ``` |
3020 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem(2), (1, false));")] |
3021 | /// ``` |
3022 | #[inline(always)] |
3023 | #[stable(feature = "wrapping", since = "1.7.0")] |
3024 | #[rustc_const_stable(feature = "const_overflowing_int_methods", since = "1.52.0")] |
3025 | #[must_use = "this returns the result of the operation, \ |
3026 | without modifying the original"] |
3027 | #[track_caller] |
3028 | pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) { |
3029 | (self % rhs, false) |
3030 | } |
3031 | |
3032 | /// Calculates the remainder `self.rem_euclid(rhs)` as if by Euclidean division. |
3033 | /// |
3034 | /// Returns a tuple of the modulo after dividing along with a boolean |
3035 | /// indicating whether an arithmetic overflow would occur. Note that for |
3036 | /// unsigned integers overflow never occurs, so the second value is |
3037 | /// always `false`. |
3038 | /// Since, for the positive integers, all common |
3039 | /// definitions of division are equal, this operation |
3040 | /// is exactly equal to `self.overflowing_rem(rhs)`. |
3041 | /// |
3042 | /// # Panics |
3043 | /// |
3044 | /// This function will panic if `rhs` is zero. |
3045 | /// |
3046 | /// # Examples |
3047 | /// |
3048 | /// Basic usage: |
3049 | /// |
3050 | /// ``` |
3051 | #[doc = concat!("assert_eq!(5", stringify!($SelfT), ".overflowing_rem_euclid(2), (1, false));")] |
3052 | /// ``` |
3053 | #[inline(always)] |
3054 | #[stable(feature = "euclidean_division", since = "1.38.0")] |
3055 | #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] |
3056 | #[must_use = "this returns the result of the operation, \ |
3057 | without modifying the original"] |
3058 | #[track_caller] |
3059 | pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) { |
3060 | (self % rhs, false) |
3061 | } |
3062 | |
3063 | /// Negates self in an overflowing fashion. |
3064 | /// |
3065 | /// Returns `!self + 1` using wrapping operations to return the value |
3066 | /// that represents the negation of this unsigned value. Note that for |
3067 | /// positive unsigned values overflow always occurs, but negating 0 does |
3068 | /// not overflow. |
3069 | /// |
3070 | /// # Examples |
3071 | /// |
3072 | /// Basic usage: |
3073 | /// |
3074 | /// ``` |
3075 | #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".overflowing_neg(), (0, false));")] |
3076 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!($SelfT), ", true));")] |
3077 | /// ``` |
3078 | #[inline(always)] |
3079 | #[stable(feature = "wrapping", since = "1.7.0")] |
3080 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
3081 | #[must_use = "this returns the result of the operation, \ |
3082 | without modifying the original"] |
3083 | pub const fn overflowing_neg(self) -> (Self, bool) { |
3084 | ((!self).wrapping_add(1), self != 0) |
3085 | } |
3086 | |
3087 | /// Shifts self left by `rhs` bits. |
3088 | /// |
3089 | /// Returns a tuple of the shifted version of self along with a boolean |
3090 | /// indicating whether the shift value was larger than or equal to the |
3091 | /// number of bits. If the shift value is too large, then value is |
3092 | /// masked (N-1) where N is the number of bits, and this value is then |
3093 | /// used to perform the shift. |
3094 | /// |
3095 | /// # Examples |
3096 | /// |
3097 | /// Basic usage: |
3098 | /// |
3099 | /// ``` |
3100 | #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(4), (0x10, false));")] |
3101 | #[doc = concat!("assert_eq!(0x1", stringify!($SelfT), ".overflowing_shl(132), (0x10, true));")] |
3102 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shl(", stringify!($BITS_MINUS_ONE), "), (0, false));")] |
3103 | /// ``` |
3104 | #[stable(feature = "wrapping", since = "1.7.0")] |
3105 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
3106 | #[must_use = "this returns the result of the operation, \ |
3107 | without modifying the original"] |
3108 | #[inline(always)] |
3109 | pub const fn overflowing_shl(self, rhs: u32) -> (Self, bool) { |
3110 | (self.wrapping_shl(rhs), rhs >= Self::BITS) |
3111 | } |
3112 | |
3113 | /// Shifts self right by `rhs` bits. |
3114 | /// |
3115 | /// Returns a tuple of the shifted version of self along with a boolean |
3116 | /// indicating whether the shift value was larger than or equal to the |
3117 | /// number of bits. If the shift value is too large, then value is |
3118 | /// masked (N-1) where N is the number of bits, and this value is then |
3119 | /// used to perform the shift. |
3120 | /// |
3121 | /// # Examples |
3122 | /// |
3123 | /// Basic usage: |
3124 | /// |
3125 | /// ``` |
3126 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(4), (0x1, false));")] |
3127 | #[doc = concat!("assert_eq!(0x10", stringify!($SelfT), ".overflowing_shr(132), (0x1, true));")] |
3128 | /// ``` |
3129 | #[stable(feature = "wrapping", since = "1.7.0")] |
3130 | #[rustc_const_stable(feature = "const_wrapping_math", since = "1.32.0")] |
3131 | #[must_use = "this returns the result of the operation, \ |
3132 | without modifying the original"] |
3133 | #[inline(always)] |
3134 | pub const fn overflowing_shr(self, rhs: u32) -> (Self, bool) { |
3135 | (self.wrapping_shr(rhs), rhs >= Self::BITS) |
3136 | } |
3137 | |
3138 | /// Raises self to the power of `exp`, using exponentiation by squaring. |
3139 | /// |
3140 | /// Returns a tuple of the exponentiation along with a bool indicating |
3141 | /// whether an overflow happened. |
3142 | /// |
3143 | /// # Examples |
3144 | /// |
3145 | /// Basic usage: |
3146 | /// |
3147 | /// ``` |
3148 | #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".overflowing_pow(5), (243, false));")] |
3149 | /// assert_eq!(3u8.overflowing_pow(6), (217, true)); |
3150 | /// ``` |
3151 | #[stable(feature = "no_panic_pow", since = "1.34.0")] |
3152 | #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] |
3153 | #[must_use = "this returns the result of the operation, \ |
3154 | without modifying the original"] |
3155 | #[inline] |
3156 | pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) { |
3157 | if exp == 0{ |
3158 | return (1,false); |
3159 | } |
3160 | let mut base = self; |
3161 | let mut acc: Self = 1; |
3162 | let mut overflown = false; |
3163 | // Scratch space for storing results of overflowing_mul. |
3164 | let mut r; |
3165 | |
3166 | loop { |
3167 | if (exp & 1) == 1 { |
3168 | r = acc.overflowing_mul(base); |
3169 | // since exp!=0, finally the exp must be 1. |
3170 | if exp == 1 { |
3171 | r.1 |= overflown; |
3172 | return r; |
3173 | } |
3174 | acc = r.0; |
3175 | overflown |= r.1; |
3176 | } |
3177 | exp /= 2; |
3178 | r = base.overflowing_mul(base); |
3179 | base = r.0; |
3180 | overflown |= r.1; |
3181 | } |
3182 | } |
3183 | |
3184 | /// Raises self to the power of `exp`, using exponentiation by squaring. |
3185 | /// |
3186 | /// # Examples |
3187 | /// |
3188 | /// Basic usage: |
3189 | /// |
3190 | /// ``` |
3191 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".pow(5), 32);")] |
3192 | /// ``` |
3193 | #[stable(feature = "rust1", since = "1.0.0")] |
3194 | #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] |
3195 | #[must_use = "this returns the result of the operation, \ |
3196 | without modifying the original"] |
3197 | #[inline] |
3198 | #[rustc_inherit_overflow_checks] |
3199 | pub const fn pow(self, mut exp: u32) -> Self { |
3200 | if exp == 0 { |
3201 | return 1; |
3202 | } |
3203 | let mut base = self; |
3204 | let mut acc = 1; |
3205 | |
3206 | if intrinsics::is_val_statically_known(exp) { |
3207 | while exp > 1 { |
3208 | if (exp & 1) == 1 { |
3209 | acc = acc * base; |
3210 | } |
3211 | exp /= 2; |
3212 | base = base * base; |
3213 | } |
3214 | |
3215 | // since exp!=0, finally the exp must be 1. |
3216 | // Deal with the final bit of the exponent separately, since |
3217 | // squaring the base afterwards is not necessary and may cause a |
3218 | // needless overflow. |
3219 | acc * base |
3220 | } else { |
3221 | // This is faster than the above when the exponent is not known |
3222 | // at compile time. We can't use the same code for the constant |
3223 | // exponent case because LLVM is currently unable to unroll |
3224 | // this loop. |
3225 | loop { |
3226 | if (exp & 1) == 1 { |
3227 | acc = acc * base; |
3228 | // since exp!=0, finally the exp must be 1. |
3229 | if exp == 1 { |
3230 | return acc; |
3231 | } |
3232 | } |
3233 | exp /= 2; |
3234 | base = base * base; |
3235 | } |
3236 | } |
3237 | } |
3238 | |
3239 | /// Returns the square root of the number, rounded down. |
3240 | /// |
3241 | /// # Examples |
3242 | /// |
3243 | /// Basic usage: |
3244 | /// ``` |
3245 | #[doc = concat!("assert_eq!(10", stringify!($SelfT), ".isqrt(), 3);")] |
3246 | /// ``` |
3247 | #[stable(feature = "isqrt", since = "1.84.0")] |
3248 | #[rustc_const_stable(feature = "isqrt", since = "1.84.0")] |
3249 | #[must_use = "this returns the result of the operation, \ |
3250 | without modifying the original"] |
3251 | #[inline] |
3252 | pub const fn isqrt(self) -> Self { |
3253 | let result = crate::num::int_sqrt::$ActualT(self as $ActualT) as $SelfT; |
3254 | |
3255 | // Inform the optimizer what the range of outputs is. If testing |
3256 | // `core` crashes with no panic message and a `num::int_sqrt::u*` |
3257 | // test failed, it's because your edits caused these assertions or |
3258 | // the assertions in `fn isqrt` of `nonzero.rs` to become false. |
3259 | // |
3260 | // SAFETY: Integer square root is a monotonically nondecreasing |
3261 | // function, which means that increasing the input will never |
3262 | // cause the output to decrease. Thus, since the input for unsigned |
3263 | // integers is bounded by `[0, <$ActualT>::MAX]`, sqrt(n) will be |
3264 | // bounded by `[sqrt(0), sqrt(<$ActualT>::MAX)]`. |
3265 | unsafe { |
3266 | const MAX_RESULT: $SelfT = crate::num::int_sqrt::$ActualT(<$ActualT>::MAX) as $SelfT; |
3267 | crate::hint::assert_unchecked(result <= MAX_RESULT); |
3268 | } |
3269 | |
3270 | result |
3271 | } |
3272 | |
3273 | /// Performs Euclidean division. |
3274 | /// |
3275 | /// Since, for the positive integers, all common |
3276 | /// definitions of division are equal, this |
3277 | /// is exactly equal to `self / rhs`. |
3278 | /// |
3279 | /// # Panics |
3280 | /// |
3281 | /// This function will panic if `rhs` is zero. |
3282 | /// |
3283 | /// # Examples |
3284 | /// |
3285 | /// Basic usage: |
3286 | /// |
3287 | /// ``` |
3288 | #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".div_euclid(4), 1); // or any other integer type")] |
3289 | /// ``` |
3290 | #[stable(feature = "euclidean_division", since = "1.38.0")] |
3291 | #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] |
3292 | #[must_use = "this returns the result of the operation, \ |
3293 | without modifying the original"] |
3294 | #[inline(always)] |
3295 | #[track_caller] |
3296 | pub const fn div_euclid(self, rhs: Self) -> Self { |
3297 | self / rhs |
3298 | } |
3299 | |
3300 | |
3301 | /// Calculates the least remainder of `self (mod rhs)`. |
3302 | /// |
3303 | /// Since, for the positive integers, all common |
3304 | /// definitions of division are equal, this |
3305 | /// is exactly equal to `self % rhs`. |
3306 | /// |
3307 | /// # Panics |
3308 | /// |
3309 | /// This function will panic if `rhs` is zero. |
3310 | /// |
3311 | /// # Examples |
3312 | /// |
3313 | /// Basic usage: |
3314 | /// |
3315 | /// ``` |
3316 | #[doc = concat!("assert_eq!(7", stringify!($SelfT), ".rem_euclid(4), 3); // or any other integer type")] |
3317 | /// ``` |
3318 | #[doc(alias = "modulo", alias = "mod")] |
3319 | #[stable(feature = "euclidean_division", since = "1.38.0")] |
3320 | #[rustc_const_stable(feature = "const_euclidean_int_methods", since = "1.52.0")] |
3321 | #[must_use = "this returns the result of the operation, \ |
3322 | without modifying the original"] |
3323 | #[inline(always)] |
3324 | #[track_caller] |
3325 | pub const fn rem_euclid(self, rhs: Self) -> Self { |
3326 | self % rhs |
3327 | } |
3328 | |
3329 | /// Calculates the quotient of `self` and `rhs`, rounding the result towards negative infinity. |
3330 | /// |
3331 | /// This is the same as performing `self / rhs` for all unsigned integers. |
3332 | /// |
3333 | /// # Panics |
3334 | /// |
3335 | /// This function will panic if `rhs` is zero. |
3336 | /// |
3337 | /// # Examples |
3338 | /// |
3339 | /// Basic usage: |
3340 | /// |
3341 | /// ``` |
3342 | /// #![feature(int_roundings)] |
3343 | #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_floor(4), 1);")] |
3344 | /// ``` |
3345 | #[unstable(feature = "int_roundings", issue = "88581")] |
3346 | #[must_use = "this returns the result of the operation, \ |
3347 | without modifying the original"] |
3348 | #[inline(always)] |
3349 | #[track_caller] |
3350 | pub const fn div_floor(self, rhs: Self) -> Self { |
3351 | self / rhs |
3352 | } |
3353 | |
3354 | /// Calculates the quotient of `self` and `rhs`, rounding the result towards positive infinity. |
3355 | /// |
3356 | /// # Panics |
3357 | /// |
3358 | /// This function will panic if `rhs` is zero. |
3359 | /// |
3360 | /// # Examples |
3361 | /// |
3362 | /// Basic usage: |
3363 | /// |
3364 | /// ``` |
3365 | #[doc = concat!("assert_eq!(7_", stringify!($SelfT), ".div_ceil(4), 2);")] |
3366 | /// ``` |
3367 | #[stable(feature = "int_roundings1", since = "1.73.0")] |
3368 | #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")] |
3369 | #[must_use = "this returns the result of the operation, \ |
3370 | without modifying the original"] |
3371 | #[inline] |
3372 | #[track_caller] |
3373 | pub const fn div_ceil(self, rhs: Self) -> Self { |
3374 | let d = self / rhs; |
3375 | let r = self % rhs; |
3376 | if r > 0 { |
3377 | d + 1 |
3378 | } else { |
3379 | d |
3380 | } |
3381 | } |
3382 | |
3383 | /// Calculates the smallest value greater than or equal to `self` that |
3384 | /// is a multiple of `rhs`. |
3385 | /// |
3386 | /// # Panics |
3387 | /// |
3388 | /// This function will panic if `rhs` is zero. |
3389 | /// |
3390 | /// ## Overflow behavior |
3391 | /// |
3392 | /// On overflow, this function will panic if overflow checks are enabled (default in debug |
3393 | /// mode) and wrap if overflow checks are disabled (default in release mode). |
3394 | /// |
3395 | /// # Examples |
3396 | /// |
3397 | /// Basic usage: |
3398 | /// |
3399 | /// ``` |
3400 | #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".next_multiple_of(8), 16);")] |
3401 | #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".next_multiple_of(8), 24);")] |
3402 | /// ``` |
3403 | #[stable(feature = "int_roundings1", since = "1.73.0")] |
3404 | #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")] |
3405 | #[must_use = "this returns the result of the operation, \ |
3406 | without modifying the original"] |
3407 | #[inline] |
3408 | #[rustc_inherit_overflow_checks] |
3409 | pub const fn next_multiple_of(self, rhs: Self) -> Self { |
3410 | match self % rhs { |
3411 | 0 => self, |
3412 | r => self + (rhs - r) |
3413 | } |
3414 | } |
3415 | |
3416 | /// Calculates the smallest value greater than or equal to `self` that |
3417 | /// is a multiple of `rhs`. Returns `None` if `rhs` is zero or the |
3418 | /// operation would result in overflow. |
3419 | /// |
3420 | /// # Examples |
3421 | /// |
3422 | /// Basic usage: |
3423 | /// |
3424 | /// ``` |
3425 | #[doc = concat!("assert_eq!(16_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(16));")] |
3426 | #[doc = concat!("assert_eq!(23_", stringify!($SelfT), ".checked_next_multiple_of(8), Some(24));")] |
3427 | #[doc = concat!("assert_eq!(1_", stringify!($SelfT), ".checked_next_multiple_of(0), None);")] |
3428 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_multiple_of(2), None);")] |
3429 | /// ``` |
3430 | #[stable(feature = "int_roundings1", since = "1.73.0")] |
3431 | #[rustc_const_stable(feature = "int_roundings1", since = "1.73.0")] |
3432 | #[must_use = "this returns the result of the operation, \ |
3433 | without modifying the original"] |
3434 | #[inline] |
3435 | pub const fn checked_next_multiple_of(self, rhs: Self) -> Option<Self> { |
3436 | match try_opt!(self.checked_rem(rhs)) { |
3437 | 0 => Some(self), |
3438 | // rhs - r cannot overflow because r is smaller than rhs |
3439 | r => self.checked_add(rhs - r) |
3440 | } |
3441 | } |
3442 | |
3443 | /// Returns `true` if `self` is an integer multiple of `rhs`, and false otherwise. |
3444 | /// |
3445 | /// This function is equivalent to `self % rhs == 0`, except that it will not panic |
3446 | /// for `rhs == 0`. Instead, `0.is_multiple_of(0) == true`, and for any non-zero `n`, |
3447 | /// `n.is_multiple_of(0) == false`. |
3448 | /// |
3449 | /// # Examples |
3450 | /// |
3451 | /// Basic usage: |
3452 | /// |
3453 | /// ``` |
3454 | #[doc = concat!("assert!(6_", stringify!($SelfT), ".is_multiple_of(2));")] |
3455 | #[doc = concat!("assert!(!5_", stringify!($SelfT), ".is_multiple_of(2));")] |
3456 | /// |
3457 | #[doc = concat!("assert!(0_", stringify!($SelfT), ".is_multiple_of(0));")] |
3458 | #[doc = concat!("assert!(!6_", stringify!($SelfT), ".is_multiple_of(0));")] |
3459 | /// ``` |
3460 | #[stable(feature = "unsigned_is_multiple_of", since = "1.87.0")] |
3461 | #[rustc_const_stable(feature = "unsigned_is_multiple_of", since = "1.87.0")] |
3462 | #[must_use] |
3463 | #[inline] |
3464 | #[rustc_inherit_overflow_checks] |
3465 | pub const fn is_multiple_of(self, rhs: Self) -> bool { |
3466 | match rhs { |
3467 | 0 => self == 0, |
3468 | _ => self % rhs == 0, |
3469 | } |
3470 | } |
3471 | |
3472 | /// Returns `true` if and only if `self == 2^k` for some unsigned integer `k`. |
3473 | /// |
3474 | /// # Examples |
3475 | /// |
3476 | /// Basic usage: |
3477 | /// |
3478 | /// ``` |
3479 | #[doc = concat!("assert!(16", stringify!($SelfT), ".is_power_of_two());")] |
3480 | #[doc = concat!("assert!(!10", stringify!($SelfT), ".is_power_of_two());")] |
3481 | /// ``` |
3482 | #[must_use] |
3483 | #[stable(feature = "rust1", since = "1.0.0")] |
3484 | #[rustc_const_stable(feature = "const_is_power_of_two", since = "1.32.0")] |
3485 | #[inline(always)] |
3486 | pub const fn is_power_of_two(self) -> bool { |
3487 | self.count_ones() == 1 |
3488 | } |
3489 | |
3490 | // Returns one less than next power of two. |
3491 | // (For 8u8 next power of two is 8u8 and for 6u8 it is 8u8) |
3492 | // |
3493 | // 8u8.one_less_than_next_power_of_two() == 7 |
3494 | // 6u8.one_less_than_next_power_of_two() == 7 |
3495 | // |
3496 | // This method cannot overflow, as in the `next_power_of_two` |
3497 | // overflow cases it instead ends up returning the maximum value |
3498 | // of the type, and can return 0 for 0. |
3499 | #[inline] |
3500 | const fn one_less_than_next_power_of_two(self) -> Self { |
3501 | if self <= 1 { return 0; } |
3502 | |
3503 | let p = self - 1; |
3504 | // SAFETY: Because `p > 0`, it cannot consist entirely of leading zeros. |
3505 | // That means the shift is always in-bounds, and some processors |
3506 | // (such as intel pre-haswell) have more efficient ctlz |
3507 | // intrinsics when the argument is non-zero. |
3508 | let z = unsafe { intrinsics::ctlz_nonzero(p) }; |
3509 | <$SelfT>::MAX >> z |
3510 | } |
3511 | |
3512 | /// Returns the smallest power of two greater than or equal to `self`. |
3513 | /// |
3514 | /// When return value overflows (i.e., `self > (1 << (N-1))` for type |
3515 | /// `uN`), it panics in debug mode and the return value is wrapped to 0 in |
3516 | /// release mode (the only situation in which this method can return 0). |
3517 | /// |
3518 | /// # Examples |
3519 | /// |
3520 | /// Basic usage: |
3521 | /// |
3522 | /// ``` |
3523 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".next_power_of_two(), 2);")] |
3524 | #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);")] |
3525 | #[doc = concat!("assert_eq!(0", stringify!($SelfT), ".next_power_of_two(), 1);")] |
3526 | /// ``` |
3527 | #[stable(feature = "rust1", since = "1.0.0")] |
3528 | #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] |
3529 | #[must_use = "this returns the result of the operation, \ |
3530 | without modifying the original"] |
3531 | #[inline] |
3532 | #[rustc_inherit_overflow_checks] |
3533 | pub const fn next_power_of_two(self) -> Self { |
3534 | self.one_less_than_next_power_of_two() + 1 |
3535 | } |
3536 | |
3537 | /// Returns the smallest power of two greater than or equal to `self`. If |
3538 | /// the next power of two is greater than the type's maximum value, |
3539 | /// `None` is returned, otherwise the power of two is wrapped in `Some`. |
3540 | /// |
3541 | /// # Examples |
3542 | /// |
3543 | /// Basic usage: |
3544 | /// |
3545 | /// ``` |
3546 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".checked_next_power_of_two(), Some(2));")] |
3547 | #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".checked_next_power_of_two(), Some(4));")] |
3548 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.checked_next_power_of_two(), None);")] |
3549 | /// ``` |
3550 | #[inline] |
3551 | #[stable(feature = "rust1", since = "1.0.0")] |
3552 | #[rustc_const_stable(feature = "const_int_pow", since = "1.50.0")] |
3553 | #[must_use = "this returns the result of the operation, \ |
3554 | without modifying the original"] |
3555 | pub const fn checked_next_power_of_two(self) -> Option<Self> { |
3556 | self.one_less_than_next_power_of_two().checked_add(1) |
3557 | } |
3558 | |
3559 | /// Returns the smallest power of two greater than or equal to `n`. If |
3560 | /// the next power of two is greater than the type's maximum value, |
3561 | /// the return value is wrapped to `0`. |
3562 | /// |
3563 | /// # Examples |
3564 | /// |
3565 | /// Basic usage: |
3566 | /// |
3567 | /// ``` |
3568 | /// #![feature(wrapping_next_power_of_two)] |
3569 | /// |
3570 | #[doc = concat!("assert_eq!(2", stringify!($SelfT), ".wrapping_next_power_of_two(), 2);")] |
3571 | #[doc = concat!("assert_eq!(3", stringify!($SelfT), ".wrapping_next_power_of_two(), 4);")] |
3572 | #[doc = concat!("assert_eq!(", stringify!($SelfT), "::MAX.wrapping_next_power_of_two(), 0);")] |
3573 | /// ``` |
3574 | #[inline] |
3575 | #[unstable(feature = "wrapping_next_power_of_two", issue = "32463", |
3576 | reason = "needs decision on wrapping behavior")] |
3577 | #[must_use = "this returns the result of the operation, \ |
3578 | without modifying the original"] |
3579 | pub const fn wrapping_next_power_of_two(self) -> Self { |
3580 | self.one_less_than_next_power_of_two().wrapping_add(1) |
3581 | } |
3582 | |
3583 | /// Returns the memory representation of this integer as a byte array in |
3584 | /// big-endian (network) byte order. |
3585 | /// |
3586 | #[doc = $to_xe_bytes_doc] |
3587 | /// |
3588 | /// # Examples |
3589 | /// |
3590 | /// ``` |
3591 | #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_be_bytes();")] |
3592 | #[doc = concat!("assert_eq!(bytes, ", $be_bytes, ");")] |
3593 | /// ``` |
3594 | #[stable(feature = "int_to_from_bytes", since = "1.32.0")] |
3595 | #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] |
3596 | #[must_use = "this returns the result of the operation, \ |
3597 | without modifying the original"] |
3598 | #[inline] |
3599 | pub const fn to_be_bytes(self) -> [u8; size_of::<Self>()] { |
3600 | self.to_be().to_ne_bytes() |
3601 | } |
3602 | |
3603 | /// Returns the memory representation of this integer as a byte array in |
3604 | /// little-endian byte order. |
3605 | /// |
3606 | #[doc = $to_xe_bytes_doc] |
3607 | /// |
3608 | /// # Examples |
3609 | /// |
3610 | /// ``` |
3611 | #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_le_bytes();")] |
3612 | #[doc = concat!("assert_eq!(bytes, ", $le_bytes, ");")] |
3613 | /// ``` |
3614 | #[stable(feature = "int_to_from_bytes", since = "1.32.0")] |
3615 | #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] |
3616 | #[must_use = "this returns the result of the operation, \ |
3617 | without modifying the original"] |
3618 | #[inline] |
3619 | pub const fn to_le_bytes(self) -> [u8; size_of::<Self>()] { |
3620 | self.to_le().to_ne_bytes() |
3621 | } |
3622 | |
3623 | /// Returns the memory representation of this integer as a byte array in |
3624 | /// native byte order. |
3625 | /// |
3626 | /// As the target platform's native endianness is used, portable code |
3627 | /// should use [`to_be_bytes`] or [`to_le_bytes`], as appropriate, |
3628 | /// instead. |
3629 | /// |
3630 | #[doc = $to_xe_bytes_doc] |
3631 | /// |
3632 | /// [`to_be_bytes`]: Self::to_be_bytes |
3633 | /// [`to_le_bytes`]: Self::to_le_bytes |
3634 | /// |
3635 | /// # Examples |
3636 | /// |
3637 | /// ``` |
3638 | #[doc = concat!("let bytes = ", $swap_op, stringify!($SelfT), ".to_ne_bytes();")] |
3639 | /// assert_eq!( |
3640 | /// bytes, |
3641 | /// if cfg!(target_endian = "big") { |
3642 | #[doc = concat!(" ", $be_bytes)] |
3643 | /// } else { |
3644 | #[doc = concat!(" ", $le_bytes)] |
3645 | /// } |
3646 | /// ); |
3647 | /// ``` |
3648 | #[stable(feature = "int_to_from_bytes", since = "1.32.0")] |
3649 | #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] |
3650 | #[must_use = "this returns the result of the operation, \ |
3651 | without modifying the original"] |
3652 | #[allow(unnecessary_transmutes)] |
3653 | // SAFETY: const sound because integers are plain old datatypes so we can always |
3654 | // transmute them to arrays of bytes |
3655 | #[inline] |
3656 | pub const fn to_ne_bytes(self) -> [u8; size_of::<Self>()] { |
3657 | // SAFETY: integers are plain old datatypes so we can always transmute them to |
3658 | // arrays of bytes |
3659 | unsafe { mem::transmute(self) } |
3660 | } |
3661 | |
3662 | /// Creates a native endian integer value from its representation |
3663 | /// as a byte array in big endian. |
3664 | /// |
3665 | #[doc = $from_xe_bytes_doc] |
3666 | /// |
3667 | /// # Examples |
3668 | /// |
3669 | /// ``` |
3670 | #[doc = concat!("let value = ", stringify!($SelfT), "::from_be_bytes(", $be_bytes, ");")] |
3671 | #[doc = concat!("assert_eq!(value, ", $swap_op, ");")] |
3672 | /// ``` |
3673 | /// |
3674 | /// When starting from a slice rather than an array, fallible conversion APIs can be used: |
3675 | /// |
3676 | /// ``` |
3677 | #[doc = concat!("fn read_be_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")] |
3678 | #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")] |
3679 | /// *input = rest; |
3680 | #[doc = concat!(" ", stringify!($SelfT), "::from_be_bytes(int_bytes.try_into().unwrap())")] |
3681 | /// } |
3682 | /// ``` |
3683 | #[stable(feature = "int_to_from_bytes", since = "1.32.0")] |
3684 | #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] |
3685 | #[must_use] |
3686 | #[inline] |
3687 | pub const fn from_be_bytes(bytes: [u8; size_of::<Self>()]) -> Self { |
3688 | Self::from_be(Self::from_ne_bytes(bytes)) |
3689 | } |
3690 | |
3691 | /// Creates a native endian integer value from its representation |
3692 | /// as a byte array in little endian. |
3693 | /// |
3694 | #[doc = $from_xe_bytes_doc] |
3695 | /// |
3696 | /// # Examples |
3697 | /// |
3698 | /// ``` |
3699 | #[doc = concat!("let value = ", stringify!($SelfT), "::from_le_bytes(", $le_bytes, ");")] |
3700 | #[doc = concat!("assert_eq!(value, ", $swap_op, ");")] |
3701 | /// ``` |
3702 | /// |
3703 | /// When starting from a slice rather than an array, fallible conversion APIs can be used: |
3704 | /// |
3705 | /// ``` |
3706 | #[doc = concat!("fn read_le_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")] |
3707 | #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")] |
3708 | /// *input = rest; |
3709 | #[doc = concat!(" ", stringify!($SelfT), "::from_le_bytes(int_bytes.try_into().unwrap())")] |
3710 | /// } |
3711 | /// ``` |
3712 | #[stable(feature = "int_to_from_bytes", since = "1.32.0")] |
3713 | #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] |
3714 | #[must_use] |
3715 | #[inline] |
3716 | pub const fn from_le_bytes(bytes: [u8; size_of::<Self>()]) -> Self { |
3717 | Self::from_le(Self::from_ne_bytes(bytes)) |
3718 | } |
3719 | |
3720 | /// Creates a native endian integer value from its memory representation |
3721 | /// as a byte array in native endianness. |
3722 | /// |
3723 | /// As the target platform's native endianness is used, portable code |
3724 | /// likely wants to use [`from_be_bytes`] or [`from_le_bytes`], as |
3725 | /// appropriate instead. |
3726 | /// |
3727 | /// [`from_be_bytes`]: Self::from_be_bytes |
3728 | /// [`from_le_bytes`]: Self::from_le_bytes |
3729 | /// |
3730 | #[doc = $from_xe_bytes_doc] |
3731 | /// |
3732 | /// # Examples |
3733 | /// |
3734 | /// ``` |
3735 | #[doc = concat!("let value = ", stringify!($SelfT), "::from_ne_bytes(if cfg!(target_endian =\" big\" ) {")] |
3736 | #[doc = concat!(" ", $be_bytes, "")] |
3737 | /// } else { |
3738 | #[doc = concat!(" ", $le_bytes, "")] |
3739 | /// }); |
3740 | #[doc = concat!("assert_eq!(value, ", $swap_op, ");")] |
3741 | /// ``` |
3742 | /// |
3743 | /// When starting from a slice rather than an array, fallible conversion APIs can be used: |
3744 | /// |
3745 | /// ``` |
3746 | #[doc = concat!("fn read_ne_", stringify!($SelfT), "(input: &mut &[u8]) -> ", stringify!($SelfT), " {")] |
3747 | #[doc = concat!(" let (int_bytes, rest) = input.split_at(size_of::<", stringify!($SelfT), ">());")] |
3748 | /// *input = rest; |
3749 | #[doc = concat!(" ", stringify!($SelfT), "::from_ne_bytes(int_bytes.try_into().unwrap())")] |
3750 | /// } |
3751 | /// ``` |
3752 | #[stable(feature = "int_to_from_bytes", since = "1.32.0")] |
3753 | #[rustc_const_stable(feature = "const_int_conversion", since = "1.44.0")] |
3754 | #[allow(unnecessary_transmutes)] |
3755 | #[must_use] |
3756 | // SAFETY: const sound because integers are plain old datatypes so we can always |
3757 | // transmute to them |
3758 | #[inline] |
3759 | pub const fn from_ne_bytes(bytes: [u8; size_of::<Self>()]) -> Self { |
3760 | // SAFETY: integers are plain old datatypes so we can always transmute to them |
3761 | unsafe { mem::transmute(bytes) } |
3762 | } |
3763 | |
3764 | /// New code should prefer to use |
3765 | #[doc = concat!("[`", stringify!($SelfT), "::MIN", "`] instead.")] |
3766 | /// |
3767 | /// Returns the smallest value that can be represented by this integer type. |
3768 | #[stable(feature = "rust1", since = "1.0.0")] |
3769 | #[rustc_promotable] |
3770 | #[inline(always)] |
3771 | #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")] |
3772 | #[deprecated(since = "TBD", note = "replaced by the `MIN` associated constant on this type")] |
3773 | #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_min_value")] |
3774 | pub const fn min_value() -> Self { Self::MIN } |
3775 | |
3776 | /// New code should prefer to use |
3777 | #[doc = concat!("[`", stringify!($SelfT), "::MAX", "`] instead.")] |
3778 | /// |
3779 | /// Returns the largest value that can be represented by this integer type. |
3780 | #[stable(feature = "rust1", since = "1.0.0")] |
3781 | #[rustc_promotable] |
3782 | #[inline(always)] |
3783 | #[rustc_const_stable(feature = "const_max_value", since = "1.32.0")] |
3784 | #[deprecated(since = "TBD", note = "replaced by the `MAX` associated constant on this type")] |
3785 | #[rustc_diagnostic_item = concat!(stringify!($SelfT), "_legacy_fn_max_value")] |
3786 | pub const fn max_value() -> Self { Self::MAX } |
3787 | } |
3788 | } |
3789 |
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