1 //! Numeric traits and functions for the built-in numeric types.
3 #![stable(feature = "rust1", since = "1.0.0")]
8 use crate::str::FromStr;
10 // Used because the `?` operator is not allowed in a const context.
11 macro_rules! try_opt {
20 #[allow_internal_unstable(const_likely)]
21 macro_rules! unlikely {
23 intrinsics::unlikely($e)
27 // All these modules are technically private and only exposed for coretests:
28 #[cfg(not(no_fp_fmt_parse))]
30 #[cfg(not(no_fp_fmt_parse))]
32 #[cfg(not(no_fp_fmt_parse))]
34 #[cfg(not(no_fp_fmt_parse))]
39 mod int_macros; // import int_impl!
41 mod uint_macros; // import uint_impl!
46 #[unstable(feature = "saturating_int_impl", issue = "87920")]
50 #[unstable(feature = "saturating_int_impl", issue = "87920")]
51 pub use saturating::Saturating;
52 #[stable(feature = "rust1", since = "1.0.0")]
53 pub use wrapping::Wrapping;
55 #[stable(feature = "rust1", since = "1.0.0")]
56 #[cfg(not(no_fp_fmt_parse))]
57 pub use dec2flt::ParseFloatError;
59 #[stable(feature = "rust1", since = "1.0.0")]
60 pub use error::ParseIntError;
62 #[stable(feature = "nonzero", since = "1.28.0")]
63 pub use nonzero::{NonZeroU128, NonZeroU16, NonZeroU32, NonZeroU64, NonZeroU8, NonZeroUsize};
65 #[stable(feature = "signed_nonzero", since = "1.34.0")]
66 pub use nonzero::{NonZeroI128, NonZeroI16, NonZeroI32, NonZeroI64, NonZeroI8, NonZeroIsize};
68 #[stable(feature = "try_from", since = "1.34.0")]
69 pub use error::TryFromIntError;
71 #[stable(feature = "int_error_matching", since = "1.55.0")]
72 pub use error::IntErrorKind;
74 macro_rules! usize_isize_to_xe_bytes_doc {
78 **Note**: This function returns an array of length 2, 4 or 8 bytes
79 depending on the target pointer size.
85 macro_rules! usize_isize_from_xe_bytes_doc {
89 **Note**: This function takes an array of length 2, 4 or 8 bytes
90 depending on the target pointer size.
96 macro_rules! widening_impl {
97 ($SelfT:ty, $WideT:ty, $BITS:literal) => {
98 /// Calculates the complete product `self * rhs` without the possibility to overflow.
100 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
101 /// of the result as two separate values, in that order.
107 /// Please note that this example is shared between integer types.
108 /// Which explains why `u32` is used here.
111 /// #![feature(bigint_helper_methods)]
112 /// assert_eq!(5u32.widening_mul(2), (10, 0));
113 /// assert_eq!(1_000_000_000u32.widening_mul(10), (1410065408, 2));
115 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
116 #[rustc_const_unstable(feature = "const_bigint_helper_methods", issue = "85532")]
117 #[must_use = "this returns the result of the operation, \
118 without modifying the original"]
120 pub const fn widening_mul(self, rhs: Self) -> (Self, Self) {
121 // note: longer-term this should be done via an intrinsic,
122 // but for now we can deal without an impl for u128/i128
123 // SAFETY: overflow will be contained within the wider types
124 let wide = unsafe { (self as $WideT).unchecked_mul(rhs as $WideT) };
125 (wide as $SelfT, (wide >> $BITS) as $SelfT)
128 /// Calculates the "full multiplication" `self * rhs + carry`
129 /// without the possibility to overflow.
131 /// This returns the low-order (wrapping) bits and the high-order (overflow) bits
132 /// of the result as two separate values, in that order.
134 /// Performs "long multiplication" which takes in an extra amount to add, and may return an
135 /// additional amount of overflow. This allows for chaining together multiple
136 /// multiplications to create "big integers" which represent larger values.
142 /// Please note that this example is shared between integer types.
143 /// Which explains why `u32` is used here.
146 /// #![feature(bigint_helper_methods)]
147 /// assert_eq!(5u32.carrying_mul(2, 0), (10, 0));
148 /// assert_eq!(5u32.carrying_mul(2, 10), (20, 0));
149 /// assert_eq!(1_000_000_000u32.carrying_mul(10, 0), (1410065408, 2));
150 /// assert_eq!(1_000_000_000u32.carrying_mul(10, 10), (1410065418, 2));
152 #[unstable(feature = "bigint_helper_methods", issue = "85532")]
153 #[rustc_const_unstable(feature = "bigint_helper_methods", issue = "85532")]
154 #[must_use = "this returns the result of the operation, \
155 without modifying the original"]
157 pub const fn carrying_mul(self, rhs: Self, carry: Self) -> (Self, Self) {
158 // note: longer-term this should be done via an intrinsic,
159 // but for now we can deal without an impl for u128/i128
160 // SAFETY: overflow will be contained within the wider types
162 (self as $WideT).unchecked_mul(rhs as $WideT).unchecked_add(carry as $WideT)
164 (wide as $SelfT, (wide >> $BITS) as $SelfT)
171 widening_impl! { i8, i16, 8 }
172 int_impl! { i8, i8, u8, 8, 7, -128, 127, 2, "-0x7e", "0xa", "0x12", "0x12", "0x48",
173 "[0x12]", "[0x12]", "", "" }
178 widening_impl! { i16, i32, 16 }
179 int_impl! { i16, i16, u16, 16, 15, -32768, 32767, 4, "-0x5ffd", "0x3a", "0x1234", "0x3412",
180 "0x2c48", "[0x34, 0x12]", "[0x12, 0x34]", "", "" }
185 widening_impl! { i32, i64, 32 }
186 int_impl! { i32, i32, u32, 32, 31, -2147483648, 2147483647, 8, "0x10000b3", "0xb301",
187 "0x12345678", "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]",
188 "[0x12, 0x34, 0x56, 0x78]", "", "" }
193 widening_impl! { i64, i128, 64 }
194 int_impl! { i64, i64, u64, 64, 63, -9223372036854775808, 9223372036854775807, 12,
195 "0xaa00000000006e1", "0x6e10aa", "0x1234567890123456", "0x5634129078563412",
196 "0x6a2c48091e6a2c48", "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
197 "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]", "", "" }
202 int_impl! { i128, i128, u128, 128, 127, -170141183460469231731687303715884105728,
203 170141183460469231731687303715884105727, 16,
204 "0x13f40000000000000000000000004f76", "0x4f7613f4", "0x12345678901234567890123456789012",
205 "0x12907856341290785634129078563412", "0x48091e6a2c48091e6a2c48091e6a2c48",
206 "[0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, \
207 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
208 "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, \
209 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12]", "", "" }
212 #[cfg(target_pointer_width = "16")]
215 widening_impl! { isize, i32, 16 }
216 int_impl! { isize, i16, usize, 16, 15, -32768, 32767, 4, "-0x5ffd", "0x3a", "0x1234",
217 "0x3412", "0x2c48", "[0x34, 0x12]", "[0x12, 0x34]",
218 usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() }
221 #[cfg(target_pointer_width = "32")]
224 widening_impl! { isize, i64, 32 }
225 int_impl! { isize, i32, usize, 32, 31, -2147483648, 2147483647, 8, "0x10000b3", "0xb301",
226 "0x12345678", "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]",
227 "[0x12, 0x34, 0x56, 0x78]",
228 usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() }
231 #[cfg(target_pointer_width = "64")]
234 widening_impl! { isize, i128, 64 }
235 int_impl! { isize, i64, usize, 64, 63, -9223372036854775808, 9223372036854775807,
236 12, "0xaa00000000006e1", "0x6e10aa", "0x1234567890123456", "0x5634129078563412",
237 "0x6a2c48091e6a2c48", "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
238 "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]",
239 usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() }
242 /// If 6th bit set ascii is upper case.
243 const ASCII_CASE_MASK: u8 = 0b0010_0000;
247 widening_impl! { u8, u16, 8 }
248 uint_impl! { u8, u8, i8, 8, 255, 2, "0x82", "0xa", "0x12", "0x12", "0x48", "[0x12]",
251 /// Checks if the value is within the ASCII range.
256 /// let ascii = 97u8;
257 /// let non_ascii = 150u8;
259 /// assert!(ascii.is_ascii());
260 /// assert!(!non_ascii.is_ascii());
262 #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
263 #[rustc_const_stable(feature = "const_ascii_methods_on_intrinsics", since = "1.43.0")]
265 pub const fn is_ascii(&self) -> bool {
269 /// Makes a copy of the value in its ASCII upper case equivalent.
271 /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
272 /// but non-ASCII letters are unchanged.
274 /// To uppercase the value in-place, use [`make_ascii_uppercase`].
279 /// let lowercase_a = 97u8;
281 /// assert_eq!(65, lowercase_a.to_ascii_uppercase());
284 /// [`make_ascii_uppercase`]: Self::make_ascii_uppercase
285 #[must_use = "to uppercase the value in-place, use `make_ascii_uppercase()`"]
286 #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
287 #[rustc_const_stable(feature = "const_ascii_methods_on_intrinsics", since = "1.52.0")]
289 pub const fn to_ascii_uppercase(&self) -> u8 {
290 // Unset the fifth bit if this is a lowercase letter
291 *self & !((self.is_ascii_lowercase() as u8) * ASCII_CASE_MASK)
294 /// Makes a copy of the value in its ASCII lower case equivalent.
296 /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
297 /// but non-ASCII letters are unchanged.
299 /// To lowercase the value in-place, use [`make_ascii_lowercase`].
304 /// let uppercase_a = 65u8;
306 /// assert_eq!(97, uppercase_a.to_ascii_lowercase());
309 /// [`make_ascii_lowercase`]: Self::make_ascii_lowercase
310 #[must_use = "to lowercase the value in-place, use `make_ascii_lowercase()`"]
311 #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
312 #[rustc_const_stable(feature = "const_ascii_methods_on_intrinsics", since = "1.52.0")]
314 pub const fn to_ascii_lowercase(&self) -> u8 {
315 // Set the fifth bit if this is an uppercase letter
316 *self | (self.is_ascii_uppercase() as u8 * ASCII_CASE_MASK)
319 /// Assumes self is ascii
321 pub(crate) const fn ascii_change_case_unchecked(&self) -> u8 {
322 *self ^ ASCII_CASE_MASK
325 /// Checks that two values are an ASCII case-insensitive match.
327 /// This is equivalent to `to_ascii_lowercase(a) == to_ascii_lowercase(b)`.
332 /// let lowercase_a = 97u8;
333 /// let uppercase_a = 65u8;
335 /// assert!(lowercase_a.eq_ignore_ascii_case(&uppercase_a));
337 #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
338 #[rustc_const_stable(feature = "const_ascii_methods_on_intrinsics", since = "1.52.0")]
340 pub const fn eq_ignore_ascii_case(&self, other: &u8) -> bool {
341 self.to_ascii_lowercase() == other.to_ascii_lowercase()
344 /// Converts this value to its ASCII upper case equivalent in-place.
346 /// ASCII letters 'a' to 'z' are mapped to 'A' to 'Z',
347 /// but non-ASCII letters are unchanged.
349 /// To return a new uppercased value without modifying the existing one, use
350 /// [`to_ascii_uppercase`].
355 /// let mut byte = b'a';
357 /// byte.make_ascii_uppercase();
359 /// assert_eq!(b'A', byte);
362 /// [`to_ascii_uppercase`]: Self::to_ascii_uppercase
363 #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
365 pub fn make_ascii_uppercase(&mut self) {
366 *self = self.to_ascii_uppercase();
369 /// Converts this value to its ASCII lower case equivalent in-place.
371 /// ASCII letters 'A' to 'Z' are mapped to 'a' to 'z',
372 /// but non-ASCII letters are unchanged.
374 /// To return a new lowercased value without modifying the existing one, use
375 /// [`to_ascii_lowercase`].
380 /// let mut byte = b'A';
382 /// byte.make_ascii_lowercase();
384 /// assert_eq!(b'a', byte);
387 /// [`to_ascii_lowercase`]: Self::to_ascii_lowercase
388 #[stable(feature = "ascii_methods_on_intrinsics", since = "1.23.0")]
390 pub fn make_ascii_lowercase(&mut self) {
391 *self = self.to_ascii_lowercase();
394 /// Checks if the value is an ASCII alphabetic character:
396 /// - U+0041 'A' ..= U+005A 'Z', or
397 /// - U+0061 'a' ..= U+007A 'z'.
402 /// let uppercase_a = b'A';
403 /// let uppercase_g = b'G';
407 /// let percent = b'%';
408 /// let space = b' ';
410 /// let esc = 0x1b_u8;
412 /// assert!(uppercase_a.is_ascii_alphabetic());
413 /// assert!(uppercase_g.is_ascii_alphabetic());
414 /// assert!(a.is_ascii_alphabetic());
415 /// assert!(g.is_ascii_alphabetic());
416 /// assert!(!zero.is_ascii_alphabetic());
417 /// assert!(!percent.is_ascii_alphabetic());
418 /// assert!(!space.is_ascii_alphabetic());
419 /// assert!(!lf.is_ascii_alphabetic());
420 /// assert!(!esc.is_ascii_alphabetic());
422 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
423 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
425 pub const fn is_ascii_alphabetic(&self) -> bool {
426 matches!(*self, b'A'..=b'Z' | b'a'..=b'z')
429 /// Checks if the value is an ASCII uppercase character:
430 /// U+0041 'A' ..= U+005A 'Z'.
435 /// let uppercase_a = b'A';
436 /// let uppercase_g = b'G';
440 /// let percent = b'%';
441 /// let space = b' ';
443 /// let esc = 0x1b_u8;
445 /// assert!(uppercase_a.is_ascii_uppercase());
446 /// assert!(uppercase_g.is_ascii_uppercase());
447 /// assert!(!a.is_ascii_uppercase());
448 /// assert!(!g.is_ascii_uppercase());
449 /// assert!(!zero.is_ascii_uppercase());
450 /// assert!(!percent.is_ascii_uppercase());
451 /// assert!(!space.is_ascii_uppercase());
452 /// assert!(!lf.is_ascii_uppercase());
453 /// assert!(!esc.is_ascii_uppercase());
455 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
456 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
458 pub const fn is_ascii_uppercase(&self) -> bool {
459 matches!(*self, b'A'..=b'Z')
462 /// Checks if the value is an ASCII lowercase character:
463 /// U+0061 'a' ..= U+007A 'z'.
468 /// let uppercase_a = b'A';
469 /// let uppercase_g = b'G';
473 /// let percent = b'%';
474 /// let space = b' ';
476 /// let esc = 0x1b_u8;
478 /// assert!(!uppercase_a.is_ascii_lowercase());
479 /// assert!(!uppercase_g.is_ascii_lowercase());
480 /// assert!(a.is_ascii_lowercase());
481 /// assert!(g.is_ascii_lowercase());
482 /// assert!(!zero.is_ascii_lowercase());
483 /// assert!(!percent.is_ascii_lowercase());
484 /// assert!(!space.is_ascii_lowercase());
485 /// assert!(!lf.is_ascii_lowercase());
486 /// assert!(!esc.is_ascii_lowercase());
488 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
489 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
491 pub const fn is_ascii_lowercase(&self) -> bool {
492 matches!(*self, b'a'..=b'z')
495 /// Checks if the value is an ASCII alphanumeric character:
497 /// - U+0041 'A' ..= U+005A 'Z', or
498 /// - U+0061 'a' ..= U+007A 'z', or
499 /// - U+0030 '0' ..= U+0039 '9'.
504 /// let uppercase_a = b'A';
505 /// let uppercase_g = b'G';
509 /// let percent = b'%';
510 /// let space = b' ';
512 /// let esc = 0x1b_u8;
514 /// assert!(uppercase_a.is_ascii_alphanumeric());
515 /// assert!(uppercase_g.is_ascii_alphanumeric());
516 /// assert!(a.is_ascii_alphanumeric());
517 /// assert!(g.is_ascii_alphanumeric());
518 /// assert!(zero.is_ascii_alphanumeric());
519 /// assert!(!percent.is_ascii_alphanumeric());
520 /// assert!(!space.is_ascii_alphanumeric());
521 /// assert!(!lf.is_ascii_alphanumeric());
522 /// assert!(!esc.is_ascii_alphanumeric());
524 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
525 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
527 pub const fn is_ascii_alphanumeric(&self) -> bool {
528 matches!(*self, b'0'..=b'9' | b'A'..=b'Z' | b'a'..=b'z')
531 /// Checks if the value is an ASCII decimal digit:
532 /// U+0030 '0' ..= U+0039 '9'.
537 /// let uppercase_a = b'A';
538 /// let uppercase_g = b'G';
542 /// let percent = b'%';
543 /// let space = b' ';
545 /// let esc = 0x1b_u8;
547 /// assert!(!uppercase_a.is_ascii_digit());
548 /// assert!(!uppercase_g.is_ascii_digit());
549 /// assert!(!a.is_ascii_digit());
550 /// assert!(!g.is_ascii_digit());
551 /// assert!(zero.is_ascii_digit());
552 /// assert!(!percent.is_ascii_digit());
553 /// assert!(!space.is_ascii_digit());
554 /// assert!(!lf.is_ascii_digit());
555 /// assert!(!esc.is_ascii_digit());
557 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
558 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
560 pub const fn is_ascii_digit(&self) -> bool {
561 matches!(*self, b'0'..=b'9')
564 /// Checks if the value is an ASCII hexadecimal digit:
566 /// - U+0030 '0' ..= U+0039 '9', or
567 /// - U+0041 'A' ..= U+0046 'F', or
568 /// - U+0061 'a' ..= U+0066 'f'.
573 /// let uppercase_a = b'A';
574 /// let uppercase_g = b'G';
578 /// let percent = b'%';
579 /// let space = b' ';
581 /// let esc = 0x1b_u8;
583 /// assert!(uppercase_a.is_ascii_hexdigit());
584 /// assert!(!uppercase_g.is_ascii_hexdigit());
585 /// assert!(a.is_ascii_hexdigit());
586 /// assert!(!g.is_ascii_hexdigit());
587 /// assert!(zero.is_ascii_hexdigit());
588 /// assert!(!percent.is_ascii_hexdigit());
589 /// assert!(!space.is_ascii_hexdigit());
590 /// assert!(!lf.is_ascii_hexdigit());
591 /// assert!(!esc.is_ascii_hexdigit());
593 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
594 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
596 pub const fn is_ascii_hexdigit(&self) -> bool {
597 matches!(*self, b'0'..=b'9' | b'A'..=b'F' | b'a'..=b'f')
600 /// Checks if the value is an ASCII punctuation character:
602 /// - U+0021 ..= U+002F `! " # $ % & ' ( ) * + , - . /`, or
603 /// - U+003A ..= U+0040 `: ; < = > ? @`, or
604 /// - U+005B ..= U+0060 ``[ \ ] ^ _ ` ``, or
605 /// - U+007B ..= U+007E `{ | } ~`
610 /// let uppercase_a = b'A';
611 /// let uppercase_g = b'G';
615 /// let percent = b'%';
616 /// let space = b' ';
618 /// let esc = 0x1b_u8;
620 /// assert!(!uppercase_a.is_ascii_punctuation());
621 /// assert!(!uppercase_g.is_ascii_punctuation());
622 /// assert!(!a.is_ascii_punctuation());
623 /// assert!(!g.is_ascii_punctuation());
624 /// assert!(!zero.is_ascii_punctuation());
625 /// assert!(percent.is_ascii_punctuation());
626 /// assert!(!space.is_ascii_punctuation());
627 /// assert!(!lf.is_ascii_punctuation());
628 /// assert!(!esc.is_ascii_punctuation());
630 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
631 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
633 pub const fn is_ascii_punctuation(&self) -> bool {
634 matches!(*self, b'!'..=b'/' | b':'..=b'@' | b'['..=b'`' | b'{'..=b'~')
637 /// Checks if the value is an ASCII graphic character:
638 /// U+0021 '!' ..= U+007E '~'.
643 /// let uppercase_a = b'A';
644 /// let uppercase_g = b'G';
648 /// let percent = b'%';
649 /// let space = b' ';
651 /// let esc = 0x1b_u8;
653 /// assert!(uppercase_a.is_ascii_graphic());
654 /// assert!(uppercase_g.is_ascii_graphic());
655 /// assert!(a.is_ascii_graphic());
656 /// assert!(g.is_ascii_graphic());
657 /// assert!(zero.is_ascii_graphic());
658 /// assert!(percent.is_ascii_graphic());
659 /// assert!(!space.is_ascii_graphic());
660 /// assert!(!lf.is_ascii_graphic());
661 /// assert!(!esc.is_ascii_graphic());
663 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
664 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
666 pub const fn is_ascii_graphic(&self) -> bool {
667 matches!(*self, b'!'..=b'~')
670 /// Checks if the value is an ASCII whitespace character:
671 /// U+0020 SPACE, U+0009 HORIZONTAL TAB, U+000A LINE FEED,
672 /// U+000C FORM FEED, or U+000D CARRIAGE RETURN.
674 /// Rust uses the WhatWG Infra Standard's [definition of ASCII
675 /// whitespace][infra-aw]. There are several other definitions in
676 /// wide use. For instance, [the POSIX locale][pct] includes
677 /// U+000B VERTICAL TAB as well as all the above characters,
678 /// but—from the very same specification—[the default rule for
679 /// "field splitting" in the Bourne shell][bfs] considers *only*
680 /// SPACE, HORIZONTAL TAB, and LINE FEED as whitespace.
682 /// If you are writing a program that will process an existing
683 /// file format, check what that format's definition of whitespace is
684 /// before using this function.
686 /// [infra-aw]: https://infra.spec.whatwg.org/#ascii-whitespace
687 /// [pct]: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap07.html#tag_07_03_01
688 /// [bfs]: https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_06_05
693 /// let uppercase_a = b'A';
694 /// let uppercase_g = b'G';
698 /// let percent = b'%';
699 /// let space = b' ';
701 /// let esc = 0x1b_u8;
703 /// assert!(!uppercase_a.is_ascii_whitespace());
704 /// assert!(!uppercase_g.is_ascii_whitespace());
705 /// assert!(!a.is_ascii_whitespace());
706 /// assert!(!g.is_ascii_whitespace());
707 /// assert!(!zero.is_ascii_whitespace());
708 /// assert!(!percent.is_ascii_whitespace());
709 /// assert!(space.is_ascii_whitespace());
710 /// assert!(lf.is_ascii_whitespace());
711 /// assert!(!esc.is_ascii_whitespace());
713 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
714 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
716 pub const fn is_ascii_whitespace(&self) -> bool {
717 matches!(*self, b'\t' | b'\n' | b'\x0C' | b'\r' | b' ')
720 /// Checks if the value is an ASCII control character:
721 /// U+0000 NUL ..= U+001F UNIT SEPARATOR, or U+007F DELETE.
722 /// Note that most ASCII whitespace characters are control
723 /// characters, but SPACE is not.
728 /// let uppercase_a = b'A';
729 /// let uppercase_g = b'G';
733 /// let percent = b'%';
734 /// let space = b' ';
736 /// let esc = 0x1b_u8;
738 /// assert!(!uppercase_a.is_ascii_control());
739 /// assert!(!uppercase_g.is_ascii_control());
740 /// assert!(!a.is_ascii_control());
741 /// assert!(!g.is_ascii_control());
742 /// assert!(!zero.is_ascii_control());
743 /// assert!(!percent.is_ascii_control());
744 /// assert!(!space.is_ascii_control());
745 /// assert!(lf.is_ascii_control());
746 /// assert!(esc.is_ascii_control());
748 #[stable(feature = "ascii_ctype_on_intrinsics", since = "1.24.0")]
749 #[rustc_const_stable(feature = "const_ascii_ctype_on_intrinsics", since = "1.47.0")]
751 pub const fn is_ascii_control(&self) -> bool {
752 matches!(*self, b'\0'..=b'\x1F' | b'\x7F')
755 /// Returns an iterator that produces an escaped version of a `u8`,
756 /// treating it as an ASCII character.
758 /// The behavior is identical to [`ascii::escape_default`].
763 /// #![feature(inherent_ascii_escape)]
765 /// assert_eq!("0", b'0'.escape_ascii().to_string());
766 /// assert_eq!("\\t", b'\t'.escape_ascii().to_string());
767 /// assert_eq!("\\r", b'\r'.escape_ascii().to_string());
768 /// assert_eq!("\\n", b'\n'.escape_ascii().to_string());
769 /// assert_eq!("\\'", b'\''.escape_ascii().to_string());
770 /// assert_eq!("\\\"", b'"'.escape_ascii().to_string());
771 /// assert_eq!("\\\\", b'\\'.escape_ascii().to_string());
772 /// assert_eq!("\\x9d", b'\x9d'.escape_ascii().to_string());
774 #[must_use = "this returns the escaped byte as an iterator, \
775 without modifying the original"]
776 #[unstable(feature = "inherent_ascii_escape", issue = "77174")]
778 pub fn escape_ascii(&self) -> ascii::EscapeDefault {
779 ascii::escape_default(*self)
785 widening_impl! { u16, u32, 16 }
786 uint_impl! { u16, u16, i16, 16, 65535, 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48",
787 "[0x34, 0x12]", "[0x12, 0x34]", "", "" }
792 widening_impl! { u32, u64, 32 }
793 uint_impl! { u32, u32, i32, 32, 4294967295, 8, "0x10000b3", "0xb301", "0x12345678",
794 "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", "[0x12, 0x34, 0x56, 0x78]", "", "" }
799 widening_impl! { u64, u128, 64 }
800 uint_impl! { u64, u64, i64, 64, 18446744073709551615, 12, "0xaa00000000006e1", "0x6e10aa",
801 "0x1234567890123456", "0x5634129078563412", "0x6a2c48091e6a2c48",
802 "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
803 "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]",
809 uint_impl! { u128, u128, i128, 128, 340282366920938463463374607431768211455, 16,
810 "0x13f40000000000000000000000004f76", "0x4f7613f4", "0x12345678901234567890123456789012",
811 "0x12907856341290785634129078563412", "0x48091e6a2c48091e6a2c48091e6a2c48",
812 "[0x12, 0x90, 0x78, 0x56, 0x34, 0x12, 0x90, 0x78, \
813 0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
814 "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56, \
815 0x78, 0x90, 0x12, 0x34, 0x56, 0x78, 0x90, 0x12]",
819 #[cfg(target_pointer_width = "16")]
822 widening_impl! { usize, u32, 16 }
823 uint_impl! { usize, u16, isize, 16, 65535, 4, "0xa003", "0x3a", "0x1234", "0x3412", "0x2c48",
824 "[0x34, 0x12]", "[0x12, 0x34]",
825 usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() }
827 #[cfg(target_pointer_width = "32")]
830 widening_impl! { usize, u64, 32 }
831 uint_impl! { usize, u32, isize, 32, 4294967295, 8, "0x10000b3", "0xb301", "0x12345678",
832 "0x78563412", "0x1e6a2c48", "[0x78, 0x56, 0x34, 0x12]", "[0x12, 0x34, 0x56, 0x78]",
833 usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() }
836 #[cfg(target_pointer_width = "64")]
839 widening_impl! { usize, u128, 64 }
840 uint_impl! { usize, u64, isize, 64, 18446744073709551615, 12, "0xaa00000000006e1", "0x6e10aa",
841 "0x1234567890123456", "0x5634129078563412", "0x6a2c48091e6a2c48",
842 "[0x56, 0x34, 0x12, 0x90, 0x78, 0x56, 0x34, 0x12]",
843 "[0x12, 0x34, 0x56, 0x78, 0x90, 0x12, 0x34, 0x56]",
844 usize_isize_to_xe_bytes_doc!(), usize_isize_from_xe_bytes_doc!() }
847 /// A classification of floating point numbers.
849 /// This `enum` is used as the return type for [`f32::classify`] and [`f64::classify`]. See
850 /// their documentation for more.
855 /// use std::num::FpCategory;
857 /// let num = 12.4_f32;
858 /// let inf = f32::INFINITY;
860 /// let sub: f32 = 1.1754942e-38;
861 /// let nan = f32::NAN;
863 /// assert_eq!(num.classify(), FpCategory::Normal);
864 /// assert_eq!(inf.classify(), FpCategory::Infinite);
865 /// assert_eq!(zero.classify(), FpCategory::Zero);
866 /// assert_eq!(nan.classify(), FpCategory::Nan);
867 /// assert_eq!(sub.classify(), FpCategory::Subnormal);
869 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
870 #[stable(feature = "rust1", since = "1.0.0")]
871 pub enum FpCategory {
872 /// NaN (not a number): this value results from calculations like `(-1.0).sqrt()`.
874 /// See [the documentation for `f32`](f32) for more information on the unusual properties
876 #[stable(feature = "rust1", since = "1.0.0")]
879 /// Positive or negative infinity, which often results from dividing a nonzero number
881 #[stable(feature = "rust1", since = "1.0.0")]
884 /// Positive or negative zero.
886 /// See [the documentation for `f32`](f32) for more information on the signedness of zeroes.
887 #[stable(feature = "rust1", since = "1.0.0")]
890 /// “Subnormal” or “denormal” floating point representation (less precise, relative to
891 /// their magnitude, than [`Normal`]).
893 /// Subnormal numbers are larger in magnitude than [`Zero`] but smaller in magnitude than all
894 /// [`Normal`] numbers.
896 /// [`Normal`]: Self::Normal
897 /// [`Zero`]: Self::Zero
898 #[stable(feature = "rust1", since = "1.0.0")]
901 /// A regular floating point number, not any of the exceptional categories.
903 /// The smallest positive normal numbers are [`f32::MIN_POSITIVE`] and [`f64::MIN_POSITIVE`],
904 /// and the largest positive normal numbers are [`f32::MAX`] and [`f64::MAX`]. (Unlike signed
905 /// integers, floating point numbers are symmetric in their range, so negating any of these
906 /// constants will produce their negative counterpart.)
907 #[stable(feature = "rust1", since = "1.0.0")]
912 trait FromStrRadixHelper: PartialOrd + Copy {
913 fn min_value() -> Self;
914 fn max_value() -> Self;
915 fn from_u32(u: u32) -> Self;
916 fn checked_mul(&self, other: u32) -> Option<Self>;
917 fn checked_sub(&self, other: u32) -> Option<Self>;
918 fn checked_add(&self, other: u32) -> Option<Self>;
921 macro_rules! from_str_radix_int_impl {
923 #[stable(feature = "rust1", since = "1.0.0")]
924 impl FromStr for $t {
925 type Err = ParseIntError;
926 fn from_str(src: &str) -> Result<Self, ParseIntError> {
927 from_str_radix(src, 10)
932 from_str_radix_int_impl! { isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128 }
935 ($($t:ty)*) => ($(impl FromStrRadixHelper for $t {
937 fn min_value() -> Self { Self::MIN }
939 fn max_value() -> Self { Self::MAX }
941 fn from_u32(u: u32) -> Self { u as Self }
943 fn checked_mul(&self, other: u32) -> Option<Self> {
944 Self::checked_mul(*self, other as Self)
947 fn checked_sub(&self, other: u32) -> Option<Self> {
948 Self::checked_sub(*self, other as Self)
951 fn checked_add(&self, other: u32) -> Option<Self> {
952 Self::checked_add(*self, other as Self)
956 doit! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize }
958 fn from_str_radix<T: FromStrRadixHelper>(src: &str, radix: u32) -> Result<T, ParseIntError> {
959 use self::IntErrorKind::*;
960 use self::ParseIntError as PIE;
963 (2..=36).contains(&radix),
964 "from_str_radix_int: must lie in the range `[2, 36]` - found {}",
969 return Err(PIE { kind: Empty });
972 let is_signed_ty = T::from_u32(0) > T::min_value();
974 // all valid digits are ascii, so we will just iterate over the utf8 bytes
975 // and cast them to chars. .to_digit() will safely return None for anything
976 // other than a valid ascii digit for the given radix, including the first-byte
977 // of multi-byte sequences
978 let src = src.as_bytes();
980 let (is_positive, digits) = match src[0] {
981 b'+' | b'-' if src[1..].is_empty() => {
982 return Err(PIE { kind: InvalidDigit });
984 b'+' => (true, &src[1..]),
985 b'-' if is_signed_ty => (false, &src[1..]),
989 let mut result = T::from_u32(0);
991 // The number is positive
993 let x = match (c as char).to_digit(radix) {
995 None => return Err(PIE { kind: InvalidDigit }),
997 result = match result.checked_mul(radix) {
998 Some(result) => result,
999 None => return Err(PIE { kind: PosOverflow }),
1001 result = match result.checked_add(x) {
1002 Some(result) => result,
1003 None => return Err(PIE { kind: PosOverflow }),
1007 // The number is negative
1009 let x = match (c as char).to_digit(radix) {
1011 None => return Err(PIE { kind: InvalidDigit }),
1013 result = match result.checked_mul(radix) {
1014 Some(result) => result,
1015 None => return Err(PIE { kind: NegOverflow }),
1017 result = match result.checked_sub(x) {
1018 Some(result) => result,
1019 None => return Err(PIE { kind: NegOverflow }),