1 // Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
2 // file at the top-level directory of this distribution and at
3 // http://rust-lang.org/COPYRIGHT.
5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8 // option. This file may not be copied, modified, or distributed
9 // except according to those terms.
11 //! Numeric traits and functions for the built-in numeric types.
13 #![stable(feature = "rust1", since = "1.0.0")]
21 /// Provides intentionally-wrapped arithmetic on `T`.
23 /// Operations like `+` on `u32` values is intended to never overflow,
24 /// and in some debug configurations overflow is detected and results
25 /// in a panic. While most arithmetic falls into this category, some
26 /// code explicitly expects and relies upon modular arithmetic (e.g.,
29 /// Wrapping arithmetic can be achieved either through methods like
30 /// `wrapping_add`, or through the `Wrapping<T>` type, which says that
31 /// all standard arithmetic operations on the underlying value are
32 /// intended to have wrapping semantics.
37 /// use std::num::Wrapping;
39 /// let zero = Wrapping(0u32);
40 /// let one = Wrapping(1u32);
42 /// assert_eq!(std::u32::MAX, (zero - one).0);
44 #[stable(feature = "rust1", since = "1.0.0")]
45 #[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default, Hash)]
46 pub struct Wrapping<T>(#[stable(feature = "rust1", since = "1.0.0")]
49 #[stable(feature = "rust1", since = "1.0.0")]
50 impl<T: fmt::Debug> fmt::Debug for Wrapping<T> {
51 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
56 #[stable(feature = "wrapping_display", since = "1.10.0")]
57 impl<T: fmt::Display> fmt::Display for Wrapping<T> {
58 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
63 #[stable(feature = "wrapping_fmt", since = "1.11.0")]
64 impl<T: fmt::Binary> fmt::Binary for Wrapping<T> {
65 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
70 #[stable(feature = "wrapping_fmt", since = "1.11.0")]
71 impl<T: fmt::Octal> fmt::Octal for Wrapping<T> {
72 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
77 #[stable(feature = "wrapping_fmt", since = "1.11.0")]
78 impl<T: fmt::LowerHex> fmt::LowerHex for Wrapping<T> {
79 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
84 #[stable(feature = "wrapping_fmt", since = "1.11.0")]
85 impl<T: fmt::UpperHex> fmt::UpperHex for Wrapping<T> {
86 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
93 // All these modules are technically private and only exposed for coretests:
99 // `Int` + `SignedInt` implemented for signed integers
100 macro_rules! int_impl {
101 ($SelfT:ty, $ActualT:ident, $UnsignedT:ty, $BITS:expr,
102 $add_with_overflow:path,
103 $sub_with_overflow:path,
104 $mul_with_overflow:path) => {
105 /// Returns the smallest value that can be represented by this integer type.
110 /// assert_eq!(i8::min_value(), -128);
112 #[stable(feature = "rust1", since = "1.0.0")]
114 pub const fn min_value() -> Self {
115 !0 ^ ((!0 as $UnsignedT) >> 1) as Self
118 /// Returns the largest value that can be represented by this integer type.
123 /// assert_eq!(i8::max_value(), 127);
125 #[stable(feature = "rust1", since = "1.0.0")]
127 pub const fn max_value() -> Self {
131 /// Converts a string slice in a given base to an integer.
133 /// Leading and trailing whitespace represent an error.
140 /// assert_eq!(i32::from_str_radix("A", 16), Ok(10));
142 #[stable(feature = "rust1", since = "1.0.0")]
143 pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> {
144 from_str_radix(src, radix)
147 /// Returns the number of ones in the binary representation of `self`.
154 /// let n = -0b1000_0000i8;
156 /// assert_eq!(n.count_ones(), 1);
158 #[stable(feature = "rust1", since = "1.0.0")]
160 pub fn count_ones(self) -> u32 { (self as $UnsignedT).count_ones() }
162 /// Returns the number of zeros in the binary representation of `self`.
169 /// let n = -0b1000_0000i8;
171 /// assert_eq!(n.count_zeros(), 7);
173 #[stable(feature = "rust1", since = "1.0.0")]
175 pub fn count_zeros(self) -> u32 {
179 /// Returns the number of leading zeros in the binary representation
189 /// assert_eq!(n.leading_zeros(), 0);
191 #[stable(feature = "rust1", since = "1.0.0")]
193 pub fn leading_zeros(self) -> u32 {
194 (self as $UnsignedT).leading_zeros()
197 /// Returns the number of trailing zeros in the binary representation
207 /// assert_eq!(n.trailing_zeros(), 2);
209 #[stable(feature = "rust1", since = "1.0.0")]
211 pub fn trailing_zeros(self) -> u32 {
212 (self as $UnsignedT).trailing_zeros()
215 /// Shifts the bits to the left by a specified amount, `n`,
216 /// wrapping the truncated bits to the end of the resulting integer.
218 /// Please note this isn't the same operation as `<<`!
225 /// let n = 0x0123456789ABCDEFi64;
226 /// let m = -0x76543210FEDCBA99i64;
228 /// assert_eq!(n.rotate_left(32), m);
230 #[stable(feature = "rust1", since = "1.0.0")]
232 pub fn rotate_left(self, n: u32) -> Self {
233 (self as $UnsignedT).rotate_left(n) as Self
236 /// Shifts the bits to the right by a specified amount, `n`,
237 /// wrapping the truncated bits to the beginning of the resulting
240 /// Please note this isn't the same operation as `>>`!
247 /// let n = 0x0123456789ABCDEFi64;
248 /// let m = -0xFEDCBA987654322i64;
250 /// assert_eq!(n.rotate_right(4), m);
252 #[stable(feature = "rust1", since = "1.0.0")]
254 pub fn rotate_right(self, n: u32) -> Self {
255 (self as $UnsignedT).rotate_right(n) as Self
258 /// Reverses the byte order of the integer.
265 /// let n = 0x0123456789ABCDEFi64;
266 /// let m = -0x1032547698BADCFFi64;
268 /// assert_eq!(n.swap_bytes(), m);
270 #[stable(feature = "rust1", since = "1.0.0")]
272 pub fn swap_bytes(self) -> Self {
273 (self as $UnsignedT).swap_bytes() as Self
276 /// Converts an integer from big endian to the target's endianness.
278 /// On big endian this is a no-op. On little endian the bytes are
286 /// let n = 0x0123456789ABCDEFi64;
288 /// if cfg!(target_endian = "big") {
289 /// assert_eq!(i64::from_be(n), n)
291 /// assert_eq!(i64::from_be(n), n.swap_bytes())
294 #[stable(feature = "rust1", since = "1.0.0")]
296 pub fn from_be(x: Self) -> Self {
297 if cfg!(target_endian = "big") { x } else { x.swap_bytes() }
300 /// Converts an integer from little endian to the target's endianness.
302 /// On little endian this is a no-op. On big endian the bytes are
310 /// let n = 0x0123456789ABCDEFi64;
312 /// if cfg!(target_endian = "little") {
313 /// assert_eq!(i64::from_le(n), n)
315 /// assert_eq!(i64::from_le(n), n.swap_bytes())
318 #[stable(feature = "rust1", since = "1.0.0")]
320 pub fn from_le(x: Self) -> Self {
321 if cfg!(target_endian = "little") { x } else { x.swap_bytes() }
324 /// Converts `self` to big endian from the target's endianness.
326 /// On big endian this is a no-op. On little endian the bytes are
334 /// let n = 0x0123456789ABCDEFi64;
336 /// if cfg!(target_endian = "big") {
337 /// assert_eq!(n.to_be(), n)
339 /// assert_eq!(n.to_be(), n.swap_bytes())
342 #[stable(feature = "rust1", since = "1.0.0")]
344 pub fn to_be(self) -> Self { // or not to be?
345 if cfg!(target_endian = "big") { self } else { self.swap_bytes() }
348 /// Converts `self` to little endian from the target's endianness.
350 /// On little endian this is a no-op. On big endian the bytes are
358 /// let n = 0x0123456789ABCDEFi64;
360 /// if cfg!(target_endian = "little") {
361 /// assert_eq!(n.to_le(), n)
363 /// assert_eq!(n.to_le(), n.swap_bytes())
366 #[stable(feature = "rust1", since = "1.0.0")]
368 pub fn to_le(self) -> Self {
369 if cfg!(target_endian = "little") { self } else { self.swap_bytes() }
372 /// Checked integer addition. Computes `self + other`, returning `None`
373 /// if overflow occurred.
380 /// assert_eq!(7i16.checked_add(32760), Some(32767));
381 /// assert_eq!(8i16.checked_add(32760), None);
383 #[stable(feature = "rust1", since = "1.0.0")]
385 pub fn checked_add(self, other: Self) -> Option<Self> {
386 let (a, b) = self.overflowing_add(other);
387 if b {None} else {Some(a)}
390 /// Checked integer subtraction. Computes `self - other`, returning
391 /// `None` if underflow occurred.
398 /// assert_eq!((-127i8).checked_sub(1), Some(-128));
399 /// assert_eq!((-128i8).checked_sub(1), None);
401 #[stable(feature = "rust1", since = "1.0.0")]
403 pub fn checked_sub(self, other: Self) -> Option<Self> {
404 let (a, b) = self.overflowing_sub(other);
405 if b {None} else {Some(a)}
408 /// Checked integer multiplication. Computes `self * other`, returning
409 /// `None` if underflow or overflow occurred.
416 /// assert_eq!(6i8.checked_mul(21), Some(126));
417 /// assert_eq!(6i8.checked_mul(22), None);
419 #[stable(feature = "rust1", since = "1.0.0")]
421 pub fn checked_mul(self, other: Self) -> Option<Self> {
422 let (a, b) = self.overflowing_mul(other);
423 if b {None} else {Some(a)}
426 /// Checked integer division. Computes `self / other`, returning `None`
427 /// if `other == 0` or the operation results in underflow or overflow.
434 /// assert_eq!((-127i8).checked_div(-1), Some(127));
435 /// assert_eq!((-128i8).checked_div(-1), None);
436 /// assert_eq!((1i8).checked_div(0), None);
438 #[stable(feature = "rust1", since = "1.0.0")]
440 pub fn checked_div(self, other: Self) -> Option<Self> {
441 if other == 0 || (self == Self::min_value() && other == -1) {
444 Some(unsafe { intrinsics::unchecked_div(self, other) })
448 /// Checked integer remainder. Computes `self % other`, returning `None`
449 /// if `other == 0` or the operation results in underflow or overflow.
458 /// assert_eq!(5i32.checked_rem(2), Some(1));
459 /// assert_eq!(5i32.checked_rem(0), None);
460 /// assert_eq!(i32::MIN.checked_rem(-1), None);
462 #[stable(feature = "wrapping", since = "1.7.0")]
464 pub fn checked_rem(self, other: Self) -> Option<Self> {
465 if other == 0 || (self == Self::min_value() && other == -1) {
468 Some(unsafe { intrinsics::unchecked_rem(self, other) })
472 /// Checked negation. Computes `-self`, returning `None` if `self ==
482 /// assert_eq!(5i32.checked_neg(), Some(-5));
483 /// assert_eq!(i32::MIN.checked_neg(), None);
485 #[stable(feature = "wrapping", since = "1.7.0")]
487 pub fn checked_neg(self) -> Option<Self> {
488 let (a, b) = self.overflowing_neg();
489 if b {None} else {Some(a)}
492 /// Checked shift left. Computes `self << rhs`, returning `None`
493 /// if `rhs` is larger than or equal to the number of bits in `self`.
500 /// assert_eq!(0x10i32.checked_shl(4), Some(0x100));
501 /// assert_eq!(0x10i32.checked_shl(33), None);
503 #[stable(feature = "wrapping", since = "1.7.0")]
505 pub fn checked_shl(self, rhs: u32) -> Option<Self> {
506 let (a, b) = self.overflowing_shl(rhs);
507 if b {None} else {Some(a)}
510 /// Checked shift right. Computes `self >> rhs`, returning `None`
511 /// if `rhs` is larger than or equal to the number of bits in `self`.
518 /// assert_eq!(0x10i32.checked_shr(4), Some(0x1));
519 /// assert_eq!(0x10i32.checked_shr(33), None);
521 #[stable(feature = "wrapping", since = "1.7.0")]
523 pub fn checked_shr(self, rhs: u32) -> Option<Self> {
524 let (a, b) = self.overflowing_shr(rhs);
525 if b {None} else {Some(a)}
528 /// Checked absolute value. Computes `self.abs()`, returning `None` if
538 /// assert_eq!((-5i32).checked_abs(), Some(5));
539 /// assert_eq!(i32::MIN.checked_abs(), None);
541 #[stable(feature = "no_panic_abs", since = "1.13.0")]
543 pub fn checked_abs(self) -> Option<Self> {
544 if self.is_negative() {
551 /// Saturating integer addition. Computes `self + other`, saturating at
552 /// the numeric bounds instead of overflowing.
559 /// assert_eq!(100i8.saturating_add(1), 101);
560 /// assert_eq!(100i8.saturating_add(127), 127);
562 #[stable(feature = "rust1", since = "1.0.0")]
564 pub fn saturating_add(self, other: Self) -> Self {
565 match self.checked_add(other) {
567 None if other >= 0 => Self::max_value(),
568 None => Self::min_value(),
572 /// Saturating integer subtraction. Computes `self - other`, saturating
573 /// at the numeric bounds instead of overflowing.
580 /// assert_eq!(100i8.saturating_sub(127), -27);
581 /// assert_eq!((-100i8).saturating_sub(127), -128);
583 #[stable(feature = "rust1", since = "1.0.0")]
585 pub fn saturating_sub(self, other: Self) -> Self {
586 match self.checked_sub(other) {
588 None if other >= 0 => Self::min_value(),
589 None => Self::max_value(),
593 /// Saturating integer multiplication. Computes `self * other`,
594 /// saturating at the numeric bounds instead of overflowing.
603 /// assert_eq!(100i32.saturating_mul(127), 12700);
604 /// assert_eq!((1i32 << 23).saturating_mul(1 << 23), i32::MAX);
605 /// assert_eq!((-1i32 << 23).saturating_mul(1 << 23), i32::MIN);
607 #[stable(feature = "wrapping", since = "1.7.0")]
609 pub fn saturating_mul(self, other: Self) -> Self {
610 self.checked_mul(other).unwrap_or_else(|| {
611 if (self < 0 && other < 0) || (self > 0 && other > 0) {
619 /// Wrapping (modular) addition. Computes `self + other`,
620 /// wrapping around at the boundary of the type.
627 /// assert_eq!(100i8.wrapping_add(27), 127);
628 /// assert_eq!(100i8.wrapping_add(127), -29);
630 #[stable(feature = "rust1", since = "1.0.0")]
632 pub fn wrapping_add(self, rhs: Self) -> Self {
634 intrinsics::overflowing_add(self, rhs)
638 /// Wrapping (modular) subtraction. Computes `self - other`,
639 /// wrapping around at the boundary of the type.
646 /// assert_eq!(0i8.wrapping_sub(127), -127);
647 /// assert_eq!((-2i8).wrapping_sub(127), 127);
649 #[stable(feature = "rust1", since = "1.0.0")]
651 pub fn wrapping_sub(self, rhs: Self) -> Self {
653 intrinsics::overflowing_sub(self, rhs)
657 /// Wrapping (modular) multiplication. Computes `self *
658 /// other`, wrapping around at the boundary of the type.
665 /// assert_eq!(10i8.wrapping_mul(12), 120);
666 /// assert_eq!(11i8.wrapping_mul(12), -124);
668 #[stable(feature = "rust1", since = "1.0.0")]
670 pub fn wrapping_mul(self, rhs: Self) -> Self {
672 intrinsics::overflowing_mul(self, rhs)
676 /// Wrapping (modular) division. Computes `self / other`,
677 /// wrapping around at the boundary of the type.
679 /// The only case where such wrapping can occur is when one
680 /// divides `MIN / -1` on a signed type (where `MIN` is the
681 /// negative minimal value for the type); this is equivalent
682 /// to `-MIN`, a positive value that is too large to represent
683 /// in the type. In such a case, this function returns `MIN`
688 /// This function will panic if `rhs` is 0.
695 /// assert_eq!(100u8.wrapping_div(10), 10);
696 /// assert_eq!((-128i8).wrapping_div(-1), -128);
698 #[stable(feature = "num_wrapping", since = "1.2.0")]
700 pub fn wrapping_div(self, rhs: Self) -> Self {
701 self.overflowing_div(rhs).0
704 /// Wrapping (modular) remainder. Computes `self % other`,
705 /// wrapping around at the boundary of the type.
707 /// Such wrap-around never actually occurs mathematically;
708 /// implementation artifacts make `x % y` invalid for `MIN /
709 /// -1` on a signed type (where `MIN` is the negative
710 /// minimal value). In such a case, this function returns `0`.
714 /// This function will panic if `rhs` is 0.
721 /// assert_eq!(100i8.wrapping_rem(10), 0);
722 /// assert_eq!((-128i8).wrapping_rem(-1), 0);
724 #[stable(feature = "num_wrapping", since = "1.2.0")]
726 pub fn wrapping_rem(self, rhs: Self) -> Self {
727 self.overflowing_rem(rhs).0
730 /// Wrapping (modular) negation. Computes `-self`,
731 /// wrapping around at the boundary of the type.
733 /// The only case where such wrapping can occur is when one
734 /// negates `MIN` on a signed type (where `MIN` is the
735 /// negative minimal value for the type); this is a positive
736 /// value that is too large to represent in the type. In such
737 /// a case, this function returns `MIN` itself.
744 /// assert_eq!(100i8.wrapping_neg(), -100);
745 /// assert_eq!((-128i8).wrapping_neg(), -128);
747 #[stable(feature = "num_wrapping", since = "1.2.0")]
749 pub fn wrapping_neg(self) -> Self {
750 self.overflowing_neg().0
753 /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
754 /// where `mask` removes any high-order bits of `rhs` that
755 /// would cause the shift to exceed the bitwidth of the type.
757 /// Note that this is *not* the same as a rotate-left; the
758 /// RHS of a wrapping shift-left is restricted to the range
759 /// of the type, rather than the bits shifted out of the LHS
760 /// being returned to the other end. The primitive integer
761 /// types all implement a `rotate_left` function, which may
762 /// be what you want instead.
769 /// assert_eq!((-1i8).wrapping_shl(7), -128);
770 /// assert_eq!((-1i8).wrapping_shl(8), -1);
772 #[stable(feature = "num_wrapping", since = "1.2.0")]
774 pub fn wrapping_shl(self, rhs: u32) -> Self {
776 intrinsics::unchecked_shl(self, (rhs & ($BITS - 1)) as $SelfT)
780 /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
781 /// where `mask` removes any high-order bits of `rhs` that
782 /// would cause the shift to exceed the bitwidth of the type.
784 /// Note that this is *not* the same as a rotate-right; the
785 /// RHS of a wrapping shift-right is restricted to the range
786 /// of the type, rather than the bits shifted out of the LHS
787 /// being returned to the other end. The primitive integer
788 /// types all implement a `rotate_right` function, which may
789 /// be what you want instead.
796 /// assert_eq!((-128i8).wrapping_shr(7), -1);
797 /// assert_eq!((-128i8).wrapping_shr(8), -128);
799 #[stable(feature = "num_wrapping", since = "1.2.0")]
801 pub fn wrapping_shr(self, rhs: u32) -> Self {
803 intrinsics::unchecked_shr(self, (rhs & ($BITS - 1)) as $SelfT)
807 /// Wrapping (modular) absolute value. Computes `self.abs()`,
808 /// wrapping around at the boundary of the type.
810 /// The only case where such wrapping can occur is when one takes
811 /// the absolute value of the negative minimal value for the type
812 /// this is a positive value that is too large to represent in the
813 /// type. In such a case, this function returns `MIN` itself.
820 /// assert_eq!(100i8.wrapping_abs(), 100);
821 /// assert_eq!((-100i8).wrapping_abs(), 100);
822 /// assert_eq!((-128i8).wrapping_abs(), -128);
823 /// assert_eq!((-128i8).wrapping_abs() as u8, 128);
825 #[stable(feature = "no_panic_abs", since = "1.13.0")]
827 pub fn wrapping_abs(self) -> Self {
828 if self.is_negative() {
835 /// Calculates `self` + `rhs`
837 /// Returns a tuple of the addition along with a boolean indicating
838 /// whether an arithmetic overflow would occur. If an overflow would
839 /// have occurred then the wrapped value is returned.
848 /// assert_eq!(5i32.overflowing_add(2), (7, false));
849 /// assert_eq!(i32::MAX.overflowing_add(1), (i32::MIN, true));
852 #[stable(feature = "wrapping", since = "1.7.0")]
853 pub fn overflowing_add(self, rhs: Self) -> (Self, bool) {
855 let (a, b) = $add_with_overflow(self as $ActualT,
861 /// Calculates `self` - `rhs`
863 /// Returns a tuple of the subtraction along with a boolean indicating
864 /// whether an arithmetic overflow would occur. If an overflow would
865 /// have occurred then the wrapped value is returned.
874 /// assert_eq!(5i32.overflowing_sub(2), (3, false));
875 /// assert_eq!(i32::MIN.overflowing_sub(1), (i32::MAX, true));
878 #[stable(feature = "wrapping", since = "1.7.0")]
879 pub fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
881 let (a, b) = $sub_with_overflow(self as $ActualT,
887 /// Calculates the multiplication of `self` and `rhs`.
889 /// Returns a tuple of the multiplication along with a boolean
890 /// indicating whether an arithmetic overflow would occur. If an
891 /// overflow would have occurred then the wrapped value is returned.
898 /// assert_eq!(5i32.overflowing_mul(2), (10, false));
899 /// assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));
902 #[stable(feature = "wrapping", since = "1.7.0")]
903 pub fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
905 let (a, b) = $mul_with_overflow(self as $ActualT,
911 /// Calculates the divisor when `self` is divided by `rhs`.
913 /// Returns a tuple of the divisor along with a boolean indicating
914 /// whether an arithmetic overflow would occur. If an overflow would
915 /// occur then self is returned.
919 /// This function will panic if `rhs` is 0.
928 /// assert_eq!(5i32.overflowing_div(2), (2, false));
929 /// assert_eq!(i32::MIN.overflowing_div(-1), (i32::MIN, true));
932 #[stable(feature = "wrapping", since = "1.7.0")]
933 pub fn overflowing_div(self, rhs: Self) -> (Self, bool) {
934 if self == Self::min_value() && rhs == -1 {
941 /// Calculates the remainder when `self` is divided by `rhs`.
943 /// Returns a tuple of the remainder after dividing along with a boolean
944 /// indicating whether an arithmetic overflow would occur. If an
945 /// overflow would occur then 0 is returned.
949 /// This function will panic if `rhs` is 0.
958 /// assert_eq!(5i32.overflowing_rem(2), (1, false));
959 /// assert_eq!(i32::MIN.overflowing_rem(-1), (0, true));
962 #[stable(feature = "wrapping", since = "1.7.0")]
963 pub fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
964 if self == Self::min_value() && rhs == -1 {
971 /// Negates self, overflowing if this is equal to the minimum value.
973 /// Returns a tuple of the negated version of self along with a boolean
974 /// indicating whether an overflow happened. If `self` is the minimum
975 /// value (e.g. `i32::MIN` for values of type `i32`), then the minimum
976 /// value will be returned again and `true` will be returned for an
977 /// overflow happening.
986 /// assert_eq!(2i32.overflowing_neg(), (-2, false));
987 /// assert_eq!(i32::MIN.overflowing_neg(), (i32::MIN, true));
990 #[stable(feature = "wrapping", since = "1.7.0")]
991 pub fn overflowing_neg(self) -> (Self, bool) {
992 if self == Self::min_value() {
993 (Self::min_value(), true)
999 /// Shifts self left by `rhs` bits.
1001 /// Returns a tuple of the shifted version of self along with a boolean
1002 /// indicating whether the shift value was larger than or equal to the
1003 /// number of bits. If the shift value is too large, then value is
1004 /// masked (N-1) where N is the number of bits, and this value is then
1005 /// used to perform the shift.
1012 /// assert_eq!(0x10i32.overflowing_shl(4), (0x100, false));
1013 /// assert_eq!(0x10i32.overflowing_shl(36), (0x100, true));
1016 #[stable(feature = "wrapping", since = "1.7.0")]
1017 pub fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
1018 (self.wrapping_shl(rhs), (rhs > ($BITS - 1)))
1021 /// Shifts self right by `rhs` bits.
1023 /// Returns a tuple of the shifted version of self along with a boolean
1024 /// indicating whether the shift value was larger than or equal to the
1025 /// number of bits. If the shift value is too large, then value is
1026 /// masked (N-1) where N is the number of bits, and this value is then
1027 /// used to perform the shift.
1034 /// assert_eq!(0x10i32.overflowing_shr(4), (0x1, false));
1035 /// assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
1038 #[stable(feature = "wrapping", since = "1.7.0")]
1039 pub fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
1040 (self.wrapping_shr(rhs), (rhs > ($BITS - 1)))
1043 /// Computes the absolute value of `self`.
1045 /// Returns a tuple of the absolute version of self along with a
1046 /// boolean indicating whether an overflow happened. If self is the
1047 /// minimum value (e.g. i32::MIN for values of type i32), then the
1048 /// minimum value will be returned again and true will be returned for
1049 /// an overflow happening.
1056 /// assert_eq!(10i8.overflowing_abs(), (10,false));
1057 /// assert_eq!((-10i8).overflowing_abs(), (10,false));
1058 /// assert_eq!((-128i8).overflowing_abs(), (-128,true));
1060 #[stable(feature = "no_panic_abs", since = "1.13.0")]
1062 pub fn overflowing_abs(self) -> (Self, bool) {
1063 if self.is_negative() {
1064 self.overflowing_neg()
1070 /// Raises self to the power of `exp`, using exponentiation by squaring.
1077 /// let x: i32 = 2; // or any other integer type
1079 /// assert_eq!(x.pow(4), 16);
1081 #[stable(feature = "rust1", since = "1.0.0")]
1083 #[rustc_inherit_overflow_checks]
1084 pub fn pow(self, mut exp: u32) -> Self {
1085 let mut base = self;
1096 // Deal with the final bit of the exponent separately, since
1097 // squaring the base afterwards is not necessary and may cause a
1098 // needless overflow.
1106 /// Computes the absolute value of `self`.
1108 /// # Overflow behavior
1110 /// The absolute value of `i32::min_value()` cannot be represented as an
1111 /// `i32`, and attempting to calculate it will cause an overflow. This
1112 /// means that code in debug mode will trigger a panic on this case and
1113 /// optimized code will return `i32::min_value()` without a panic.
1120 /// assert_eq!(10i8.abs(), 10);
1121 /// assert_eq!((-10i8).abs(), 10);
1123 #[stable(feature = "rust1", since = "1.0.0")]
1125 #[rustc_inherit_overflow_checks]
1126 pub fn abs(self) -> Self {
1127 if self.is_negative() {
1128 // Note that the #[inline] above means that the overflow
1129 // semantics of this negation depend on the crate we're being
1137 /// Returns a number representing sign of `self`.
1139 /// - `0` if the number is zero
1140 /// - `1` if the number is positive
1141 /// - `-1` if the number is negative
1148 /// assert_eq!(10i8.signum(), 1);
1149 /// assert_eq!(0i8.signum(), 0);
1150 /// assert_eq!((-10i8).signum(), -1);
1152 #[stable(feature = "rust1", since = "1.0.0")]
1154 pub fn signum(self) -> Self {
1162 /// Returns `true` if `self` is positive and `false` if the number
1163 /// is zero or negative.
1170 /// assert!(10i8.is_positive());
1171 /// assert!(!(-10i8).is_positive());
1173 #[stable(feature = "rust1", since = "1.0.0")]
1175 pub fn is_positive(self) -> bool { self > 0 }
1177 /// Returns `true` if `self` is negative and `false` if the number
1178 /// is zero or positive.
1185 /// assert!((-10i8).is_negative());
1186 /// assert!(!10i8.is_negative());
1188 #[stable(feature = "rust1", since = "1.0.0")]
1190 pub fn is_negative(self) -> bool { self < 0 }
1196 int_impl! { i8, i8, u8, 8,
1197 intrinsics::add_with_overflow,
1198 intrinsics::sub_with_overflow,
1199 intrinsics::mul_with_overflow }
1204 int_impl! { i16, i16, u16, 16,
1205 intrinsics::add_with_overflow,
1206 intrinsics::sub_with_overflow,
1207 intrinsics::mul_with_overflow }
1212 int_impl! { i32, i32, u32, 32,
1213 intrinsics::add_with_overflow,
1214 intrinsics::sub_with_overflow,
1215 intrinsics::mul_with_overflow }
1220 int_impl! { i64, i64, u64, 64,
1221 intrinsics::add_with_overflow,
1222 intrinsics::sub_with_overflow,
1223 intrinsics::mul_with_overflow }
1228 int_impl! { i128, i128, u128, 128,
1229 intrinsics::add_with_overflow,
1230 intrinsics::sub_with_overflow,
1231 intrinsics::mul_with_overflow }
1234 #[cfg(target_pointer_width = "16")]
1237 int_impl! { isize, i16, u16, 16,
1238 intrinsics::add_with_overflow,
1239 intrinsics::sub_with_overflow,
1240 intrinsics::mul_with_overflow }
1243 #[cfg(target_pointer_width = "32")]
1246 int_impl! { isize, i32, u32, 32,
1247 intrinsics::add_with_overflow,
1248 intrinsics::sub_with_overflow,
1249 intrinsics::mul_with_overflow }
1252 #[cfg(target_pointer_width = "64")]
1255 int_impl! { isize, i64, u64, 64,
1256 intrinsics::add_with_overflow,
1257 intrinsics::sub_with_overflow,
1258 intrinsics::mul_with_overflow }
1261 // `Int` + `UnsignedInt` implemented for unsigned integers
1262 macro_rules! uint_impl {
1263 ($SelfT:ty, $ActualT:ty, $BITS:expr,
1268 $add_with_overflow:path,
1269 $sub_with_overflow:path,
1270 $mul_with_overflow:path) => {
1271 /// Returns the smallest value that can be represented by this integer type.
1276 /// assert_eq!(u8::min_value(), 0);
1278 #[stable(feature = "rust1", since = "1.0.0")]
1280 pub const fn min_value() -> Self { 0 }
1282 /// Returns the largest value that can be represented by this integer type.
1287 /// assert_eq!(u8::max_value(), 255);
1289 #[stable(feature = "rust1", since = "1.0.0")]
1291 pub const fn max_value() -> Self { !0 }
1293 /// Converts a string slice in a given base to an integer.
1295 /// Leading and trailing whitespace represent an error.
1302 /// assert_eq!(u32::from_str_radix("A", 16), Ok(10));
1304 #[stable(feature = "rust1", since = "1.0.0")]
1305 pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> {
1306 from_str_radix(src, radix)
1309 /// Returns the number of ones in the binary representation of `self`.
1316 /// let n = 0b01001100u8;
1318 /// assert_eq!(n.count_ones(), 3);
1320 #[stable(feature = "rust1", since = "1.0.0")]
1322 pub fn count_ones(self) -> u32 {
1323 unsafe { $ctpop(self as $ActualT) as u32 }
1326 /// Returns the number of zeros in the binary representation of `self`.
1333 /// let n = 0b01001100u8;
1335 /// assert_eq!(n.count_zeros(), 5);
1337 #[stable(feature = "rust1", since = "1.0.0")]
1339 pub fn count_zeros(self) -> u32 {
1340 (!self).count_ones()
1343 /// Returns the number of leading zeros in the binary representation
1351 /// let n = 0b0101000u16;
1353 /// assert_eq!(n.leading_zeros(), 10);
1355 #[stable(feature = "rust1", since = "1.0.0")]
1357 pub fn leading_zeros(self) -> u32 {
1358 unsafe { $ctlz(self as $ActualT) as u32 }
1361 /// Returns the number of trailing zeros in the binary representation
1369 /// let n = 0b0101000u16;
1371 /// assert_eq!(n.trailing_zeros(), 3);
1373 #[stable(feature = "rust1", since = "1.0.0")]
1375 pub fn trailing_zeros(self) -> u32 {
1376 // As of LLVM 3.6 the codegen for the zero-safe cttz8 intrinsic
1377 // emits two conditional moves on x86_64. By promoting the value to
1378 // u16 and setting bit 8, we get better code without any conditional
1380 // FIXME: There's a LLVM patch (http://reviews.llvm.org/D9284)
1381 // pending, remove this workaround once LLVM generates better code
1385 intrinsics::cttz(self as u16 | 0x100) as u32
1387 intrinsics::cttz(self) as u32
1392 /// Shifts the bits to the left by a specified amount, `n`,
1393 /// wrapping the truncated bits to the end of the resulting integer.
1395 /// Please note this isn't the same operation as `<<`!
1402 /// let n = 0x0123456789ABCDEFu64;
1403 /// let m = 0x3456789ABCDEF012u64;
1405 /// assert_eq!(n.rotate_left(12), m);
1407 #[stable(feature = "rust1", since = "1.0.0")]
1409 pub fn rotate_left(self, n: u32) -> Self {
1410 // Protect against undefined behaviour for over-long bit shifts
1412 (self << n) | (self >> (($BITS - n) % $BITS))
1415 /// Shifts the bits to the right by a specified amount, `n`,
1416 /// wrapping the truncated bits to the beginning of the resulting
1419 /// Please note this isn't the same operation as `>>`!
1426 /// let n = 0x0123456789ABCDEFu64;
1427 /// let m = 0xDEF0123456789ABCu64;
1429 /// assert_eq!(n.rotate_right(12), m);
1431 #[stable(feature = "rust1", since = "1.0.0")]
1433 pub fn rotate_right(self, n: u32) -> Self {
1434 // Protect against undefined behaviour for over-long bit shifts
1436 (self >> n) | (self << (($BITS - n) % $BITS))
1439 /// Reverses the byte order of the integer.
1446 /// let n = 0x0123456789ABCDEFu64;
1447 /// let m = 0xEFCDAB8967452301u64;
1449 /// assert_eq!(n.swap_bytes(), m);
1451 #[stable(feature = "rust1", since = "1.0.0")]
1453 pub fn swap_bytes(self) -> Self {
1454 unsafe { $bswap(self as $ActualT) as Self }
1457 /// Converts an integer from big endian to the target's endianness.
1459 /// On big endian this is a no-op. On little endian the bytes are
1467 /// let n = 0x0123456789ABCDEFu64;
1469 /// if cfg!(target_endian = "big") {
1470 /// assert_eq!(u64::from_be(n), n)
1472 /// assert_eq!(u64::from_be(n), n.swap_bytes())
1475 #[stable(feature = "rust1", since = "1.0.0")]
1477 pub fn from_be(x: Self) -> Self {
1478 if cfg!(target_endian = "big") { x } else { x.swap_bytes() }
1481 /// Converts an integer from little endian to the target's endianness.
1483 /// On little endian this is a no-op. On big endian the bytes are
1491 /// let n = 0x0123456789ABCDEFu64;
1493 /// if cfg!(target_endian = "little") {
1494 /// assert_eq!(u64::from_le(n), n)
1496 /// assert_eq!(u64::from_le(n), n.swap_bytes())
1499 #[stable(feature = "rust1", since = "1.0.0")]
1501 pub fn from_le(x: Self) -> Self {
1502 if cfg!(target_endian = "little") { x } else { x.swap_bytes() }
1505 /// Converts `self` to big endian from the target's endianness.
1507 /// On big endian this is a no-op. On little endian the bytes are
1515 /// let n = 0x0123456789ABCDEFu64;
1517 /// if cfg!(target_endian = "big") {
1518 /// assert_eq!(n.to_be(), n)
1520 /// assert_eq!(n.to_be(), n.swap_bytes())
1523 #[stable(feature = "rust1", since = "1.0.0")]
1525 pub fn to_be(self) -> Self { // or not to be?
1526 if cfg!(target_endian = "big") { self } else { self.swap_bytes() }
1529 /// Converts `self` to little endian from the target's endianness.
1531 /// On little endian this is a no-op. On big endian the bytes are
1539 /// let n = 0x0123456789ABCDEFu64;
1541 /// if cfg!(target_endian = "little") {
1542 /// assert_eq!(n.to_le(), n)
1544 /// assert_eq!(n.to_le(), n.swap_bytes())
1547 #[stable(feature = "rust1", since = "1.0.0")]
1549 pub fn to_le(self) -> Self {
1550 if cfg!(target_endian = "little") { self } else { self.swap_bytes() }
1553 /// Checked integer addition. Computes `self + other`, returning `None`
1554 /// if overflow occurred.
1561 /// assert_eq!(5u16.checked_add(65530), Some(65535));
1562 /// assert_eq!(6u16.checked_add(65530), None);
1564 #[stable(feature = "rust1", since = "1.0.0")]
1566 pub fn checked_add(self, other: Self) -> Option<Self> {
1567 let (a, b) = self.overflowing_add(other);
1568 if b {None} else {Some(a)}
1571 /// Checked integer subtraction. Computes `self - other`, returning
1572 /// `None` if underflow occurred.
1579 /// assert_eq!(1u8.checked_sub(1), Some(0));
1580 /// assert_eq!(0u8.checked_sub(1), None);
1582 #[stable(feature = "rust1", since = "1.0.0")]
1584 pub fn checked_sub(self, other: Self) -> Option<Self> {
1585 let (a, b) = self.overflowing_sub(other);
1586 if b {None} else {Some(a)}
1589 /// Checked integer multiplication. Computes `self * other`, returning
1590 /// `None` if underflow or overflow occurred.
1597 /// assert_eq!(5u8.checked_mul(51), Some(255));
1598 /// assert_eq!(5u8.checked_mul(52), None);
1600 #[stable(feature = "rust1", since = "1.0.0")]
1602 pub fn checked_mul(self, other: Self) -> Option<Self> {
1603 let (a, b) = self.overflowing_mul(other);
1604 if b {None} else {Some(a)}
1607 /// Checked integer division. Computes `self / other`, returning `None`
1608 /// if `other == 0` or the operation results in underflow or overflow.
1615 /// assert_eq!(128u8.checked_div(2), Some(64));
1616 /// assert_eq!(1u8.checked_div(0), None);
1618 #[stable(feature = "rust1", since = "1.0.0")]
1620 pub fn checked_div(self, other: Self) -> Option<Self> {
1623 other => Some(unsafe { intrinsics::unchecked_div(self, other) }),
1627 /// Checked integer remainder. Computes `self % other`, returning `None`
1628 /// if `other == 0` or the operation results in underflow or overflow.
1635 /// assert_eq!(5u32.checked_rem(2), Some(1));
1636 /// assert_eq!(5u32.checked_rem(0), None);
1638 #[stable(feature = "wrapping", since = "1.7.0")]
1640 pub fn checked_rem(self, other: Self) -> Option<Self> {
1644 Some(unsafe { intrinsics::unchecked_rem(self, other) })
1648 /// Checked negation. Computes `-self`, returning `None` unless `self ==
1651 /// Note that negating any positive integer will overflow.
1658 /// assert_eq!(0u32.checked_neg(), Some(0));
1659 /// assert_eq!(1u32.checked_neg(), None);
1661 #[stable(feature = "wrapping", since = "1.7.0")]
1663 pub fn checked_neg(self) -> Option<Self> {
1664 let (a, b) = self.overflowing_neg();
1665 if b {None} else {Some(a)}
1668 /// Checked shift left. Computes `self << rhs`, returning `None`
1669 /// if `rhs` is larger than or equal to the number of bits in `self`.
1676 /// assert_eq!(0x10u32.checked_shl(4), Some(0x100));
1677 /// assert_eq!(0x10u32.checked_shl(33), None);
1679 #[stable(feature = "wrapping", since = "1.7.0")]
1681 pub fn checked_shl(self, rhs: u32) -> Option<Self> {
1682 let (a, b) = self.overflowing_shl(rhs);
1683 if b {None} else {Some(a)}
1686 /// Checked shift right. Computes `self >> rhs`, returning `None`
1687 /// if `rhs` is larger than or equal to the number of bits in `self`.
1694 /// assert_eq!(0x10u32.checked_shr(4), Some(0x1));
1695 /// assert_eq!(0x10u32.checked_shr(33), None);
1697 #[stable(feature = "wrapping", since = "1.7.0")]
1699 pub fn checked_shr(self, rhs: u32) -> Option<Self> {
1700 let (a, b) = self.overflowing_shr(rhs);
1701 if b {None} else {Some(a)}
1704 /// Saturating integer addition. Computes `self + other`, saturating at
1705 /// the numeric bounds instead of overflowing.
1712 /// assert_eq!(100u8.saturating_add(1), 101);
1713 /// assert_eq!(200u8.saturating_add(127), 255);
1715 #[stable(feature = "rust1", since = "1.0.0")]
1717 pub fn saturating_add(self, other: Self) -> Self {
1718 match self.checked_add(other) {
1720 None => Self::max_value(),
1724 /// Saturating integer subtraction. Computes `self - other`, saturating
1725 /// at the numeric bounds instead of overflowing.
1732 /// assert_eq!(100u8.saturating_sub(27), 73);
1733 /// assert_eq!(13u8.saturating_sub(127), 0);
1735 #[stable(feature = "rust1", since = "1.0.0")]
1737 pub fn saturating_sub(self, other: Self) -> Self {
1738 match self.checked_sub(other) {
1740 None => Self::min_value(),
1744 /// Saturating integer multiplication. Computes `self * other`,
1745 /// saturating at the numeric bounds instead of overflowing.
1754 /// assert_eq!(100u32.saturating_mul(127), 12700);
1755 /// assert_eq!((1u32 << 23).saturating_mul(1 << 23), u32::MAX);
1757 #[stable(feature = "wrapping", since = "1.7.0")]
1759 pub fn saturating_mul(self, other: Self) -> Self {
1760 self.checked_mul(other).unwrap_or(Self::max_value())
1763 /// Wrapping (modular) addition. Computes `self + other`,
1764 /// wrapping around at the boundary of the type.
1771 /// assert_eq!(200u8.wrapping_add(55), 255);
1772 /// assert_eq!(200u8.wrapping_add(155), 99);
1774 #[stable(feature = "rust1", since = "1.0.0")]
1776 pub fn wrapping_add(self, rhs: Self) -> Self {
1778 intrinsics::overflowing_add(self, rhs)
1782 /// Wrapping (modular) subtraction. Computes `self - other`,
1783 /// wrapping around at the boundary of the type.
1790 /// assert_eq!(100u8.wrapping_sub(100), 0);
1791 /// assert_eq!(100u8.wrapping_sub(155), 201);
1793 #[stable(feature = "rust1", since = "1.0.0")]
1795 pub fn wrapping_sub(self, rhs: Self) -> Self {
1797 intrinsics::overflowing_sub(self, rhs)
1801 /// Wrapping (modular) multiplication. Computes `self *
1802 /// other`, wrapping around at the boundary of the type.
1809 /// assert_eq!(10u8.wrapping_mul(12), 120);
1810 /// assert_eq!(25u8.wrapping_mul(12), 44);
1812 #[stable(feature = "rust1", since = "1.0.0")]
1814 pub fn wrapping_mul(self, rhs: Self) -> Self {
1816 intrinsics::overflowing_mul(self, rhs)
1820 /// Wrapping (modular) division. Computes `self / other`.
1821 /// Wrapped division on unsigned types is just normal division.
1822 /// There's no way wrapping could ever happen.
1823 /// This function exists, so that all operations
1824 /// are accounted for in the wrapping operations.
1831 /// assert_eq!(100u8.wrapping_div(10), 10);
1833 #[stable(feature = "num_wrapping", since = "1.2.0")]
1835 pub fn wrapping_div(self, rhs: Self) -> Self {
1839 /// Wrapping (modular) remainder. Computes `self % other`.
1840 /// Wrapped remainder calculation on unsigned types is
1841 /// just the regular remainder calculation.
1842 /// There's no way wrapping could ever happen.
1843 /// This function exists, so that all operations
1844 /// are accounted for in the wrapping operations.
1851 /// assert_eq!(100u8.wrapping_rem(10), 0);
1853 #[stable(feature = "num_wrapping", since = "1.2.0")]
1855 pub fn wrapping_rem(self, rhs: Self) -> Self {
1859 /// Wrapping (modular) negation. Computes `-self`,
1860 /// wrapping around at the boundary of the type.
1862 /// Since unsigned types do not have negative equivalents
1863 /// all applications of this function will wrap (except for `-0`).
1864 /// For values smaller than the corresponding signed type's maximum
1865 /// the result is the same as casting the corresponding signed value.
1866 /// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where
1867 /// `MAX` is the corresponding signed type's maximum.
1874 /// assert_eq!(100u8.wrapping_neg(), 156);
1875 /// assert_eq!(0u8.wrapping_neg(), 0);
1876 /// assert_eq!(180u8.wrapping_neg(), 76);
1877 /// assert_eq!(180u8.wrapping_neg(), (127 + 1) - (180u8 - (127 + 1)));
1879 #[stable(feature = "num_wrapping", since = "1.2.0")]
1881 pub fn wrapping_neg(self) -> Self {
1882 self.overflowing_neg().0
1885 /// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
1886 /// where `mask` removes any high-order bits of `rhs` that
1887 /// would cause the shift to exceed the bitwidth of the type.
1889 /// Note that this is *not* the same as a rotate-left; the
1890 /// RHS of a wrapping shift-left is restricted to the range
1891 /// of the type, rather than the bits shifted out of the LHS
1892 /// being returned to the other end. The primitive integer
1893 /// types all implement a `rotate_left` function, which may
1894 /// be what you want instead.
1901 /// assert_eq!(1u8.wrapping_shl(7), 128);
1902 /// assert_eq!(1u8.wrapping_shl(8), 1);
1904 #[stable(feature = "num_wrapping", since = "1.2.0")]
1906 pub fn wrapping_shl(self, rhs: u32) -> Self {
1908 intrinsics::unchecked_shl(self, (rhs & ($BITS - 1)) as $SelfT)
1912 /// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
1913 /// where `mask` removes any high-order bits of `rhs` that
1914 /// would cause the shift to exceed the bitwidth of the type.
1916 /// Note that this is *not* the same as a rotate-right; the
1917 /// RHS of a wrapping shift-right is restricted to the range
1918 /// of the type, rather than the bits shifted out of the LHS
1919 /// being returned to the other end. The primitive integer
1920 /// types all implement a `rotate_right` function, which may
1921 /// be what you want instead.
1928 /// assert_eq!(128u8.wrapping_shr(7), 1);
1929 /// assert_eq!(128u8.wrapping_shr(8), 128);
1931 #[stable(feature = "num_wrapping", since = "1.2.0")]
1933 pub fn wrapping_shr(self, rhs: u32) -> Self {
1935 intrinsics::unchecked_shr(self, (rhs & ($BITS - 1)) as $SelfT)
1939 /// Calculates `self` + `rhs`
1941 /// Returns a tuple of the addition along with a boolean indicating
1942 /// whether an arithmetic overflow would occur. If an overflow would
1943 /// have occurred then the wrapped value is returned.
1952 /// assert_eq!(5u32.overflowing_add(2), (7, false));
1953 /// assert_eq!(u32::MAX.overflowing_add(1), (0, true));
1956 #[stable(feature = "wrapping", since = "1.7.0")]
1957 pub fn overflowing_add(self, rhs: Self) -> (Self, bool) {
1959 let (a, b) = $add_with_overflow(self as $ActualT,
1965 /// Calculates `self` - `rhs`
1967 /// Returns a tuple of the subtraction along with a boolean indicating
1968 /// whether an arithmetic overflow would occur. If an overflow would
1969 /// have occurred then the wrapped value is returned.
1978 /// assert_eq!(5u32.overflowing_sub(2), (3, false));
1979 /// assert_eq!(0u32.overflowing_sub(1), (u32::MAX, true));
1982 #[stable(feature = "wrapping", since = "1.7.0")]
1983 pub fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
1985 let (a, b) = $sub_with_overflow(self as $ActualT,
1991 /// Calculates the multiplication of `self` and `rhs`.
1993 /// Returns a tuple of the multiplication along with a boolean
1994 /// indicating whether an arithmetic overflow would occur. If an
1995 /// overflow would have occurred then the wrapped value is returned.
2002 /// assert_eq!(5u32.overflowing_mul(2), (10, false));
2003 /// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
2006 #[stable(feature = "wrapping", since = "1.7.0")]
2007 pub fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
2009 let (a, b) = $mul_with_overflow(self as $ActualT,
2015 /// Calculates the divisor when `self` is divided by `rhs`.
2017 /// Returns a tuple of the divisor along with a boolean indicating
2018 /// whether an arithmetic overflow would occur. Note that for unsigned
2019 /// integers overflow never occurs, so the second value is always
2024 /// This function will panic if `rhs` is 0.
2031 /// assert_eq!(5u32.overflowing_div(2), (2, false));
2034 #[stable(feature = "wrapping", since = "1.7.0")]
2035 pub fn overflowing_div(self, rhs: Self) -> (Self, bool) {
2039 /// Calculates the remainder when `self` is divided by `rhs`.
2041 /// Returns a tuple of the remainder after dividing along with a boolean
2042 /// indicating whether an arithmetic overflow would occur. Note that for
2043 /// unsigned integers overflow never occurs, so the second value is
2048 /// This function will panic if `rhs` is 0.
2055 /// assert_eq!(5u32.overflowing_rem(2), (1, false));
2058 #[stable(feature = "wrapping", since = "1.7.0")]
2059 pub fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
2063 /// Negates self in an overflowing fashion.
2065 /// Returns `!self + 1` using wrapping operations to return the value
2066 /// that represents the negation of this unsigned value. Note that for
2067 /// positive unsigned values overflow always occurs, but negating 0 does
2075 /// assert_eq!(0u32.overflowing_neg(), (0, false));
2076 /// assert_eq!(2u32.overflowing_neg(), (-2i32 as u32, true));
2079 #[stable(feature = "wrapping", since = "1.7.0")]
2080 pub fn overflowing_neg(self) -> (Self, bool) {
2081 ((!self).wrapping_add(1), self != 0)
2084 /// Shifts self left by `rhs` bits.
2086 /// Returns a tuple of the shifted version of self along with a boolean
2087 /// indicating whether the shift value was larger than or equal to the
2088 /// number of bits. If the shift value is too large, then value is
2089 /// masked (N-1) where N is the number of bits, and this value is then
2090 /// used to perform the shift.
2097 /// assert_eq!(0x10u32.overflowing_shl(4), (0x100, false));
2098 /// assert_eq!(0x10u32.overflowing_shl(36), (0x100, true));
2101 #[stable(feature = "wrapping", since = "1.7.0")]
2102 pub fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
2103 (self.wrapping_shl(rhs), (rhs > ($BITS - 1)))
2106 /// Shifts self right by `rhs` bits.
2108 /// Returns a tuple of the shifted version of self along with a boolean
2109 /// indicating whether the shift value was larger than or equal to the
2110 /// number of bits. If the shift value is too large, then value is
2111 /// masked (N-1) where N is the number of bits, and this value is then
2112 /// used to perform the shift.
2119 /// assert_eq!(0x10u32.overflowing_shr(4), (0x1, false));
2120 /// assert_eq!(0x10u32.overflowing_shr(36), (0x1, true));
2123 #[stable(feature = "wrapping", since = "1.7.0")]
2124 pub fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
2125 (self.wrapping_shr(rhs), (rhs > ($BITS - 1)))
2129 /// Raises self to the power of `exp`, using exponentiation by squaring.
2136 /// assert_eq!(2u32.pow(4), 16);
2138 #[stable(feature = "rust1", since = "1.0.0")]
2140 #[rustc_inherit_overflow_checks]
2141 pub fn pow(self, mut exp: u32) -> Self {
2142 let mut base = self;
2153 // Deal with the final bit of the exponent separately, since
2154 // squaring the base afterwards is not necessary and may cause a
2155 // needless overflow.
2163 /// Returns `true` if and only if `self == 2^k` for some `k`.
2170 /// assert!(16u8.is_power_of_two());
2171 /// assert!(!10u8.is_power_of_two());
2173 #[stable(feature = "rust1", since = "1.0.0")]
2175 pub fn is_power_of_two(self) -> bool {
2176 (self.wrapping_sub(1)) & self == 0 && !(self == 0)
2179 /// Returns the smallest power of two greater than or equal to `self`.
2180 /// Unspecified behavior on overflow.
2187 /// assert_eq!(2u8.next_power_of_two(), 2);
2188 /// assert_eq!(3u8.next_power_of_two(), 4);
2190 #[stable(feature = "rust1", since = "1.0.0")]
2192 pub fn next_power_of_two(self) -> Self {
2193 let bits = size_of::<Self>() * 8;
2195 one << ((bits - self.wrapping_sub(one).leading_zeros() as usize) % bits)
2198 /// Returns the smallest power of two greater than or equal to `n`. If
2199 /// the next power of two is greater than the type's maximum value,
2200 /// `None` is returned, otherwise the power of two is wrapped in `Some`.
2207 /// assert_eq!(2u8.checked_next_power_of_two(), Some(2));
2208 /// assert_eq!(3u8.checked_next_power_of_two(), Some(4));
2209 /// assert_eq!(200u8.checked_next_power_of_two(), None);
2211 #[stable(feature = "rust1", since = "1.0.0")]
2212 pub fn checked_next_power_of_two(self) -> Option<Self> {
2213 let npot = self.next_power_of_two();
2225 uint_impl! { u8, u8, 8,
2230 intrinsics::add_with_overflow,
2231 intrinsics::sub_with_overflow,
2232 intrinsics::mul_with_overflow }
2237 uint_impl! { u16, u16, 16,
2242 intrinsics::add_with_overflow,
2243 intrinsics::sub_with_overflow,
2244 intrinsics::mul_with_overflow }
2249 uint_impl! { u32, u32, 32,
2254 intrinsics::add_with_overflow,
2255 intrinsics::sub_with_overflow,
2256 intrinsics::mul_with_overflow }
2261 uint_impl! { u64, u64, 64,
2266 intrinsics::add_with_overflow,
2267 intrinsics::sub_with_overflow,
2268 intrinsics::mul_with_overflow }
2273 uint_impl! { u128, u128, 128,
2278 intrinsics::add_with_overflow,
2279 intrinsics::sub_with_overflow,
2280 intrinsics::mul_with_overflow }
2283 #[cfg(target_pointer_width = "16")]
2286 uint_impl! { usize, u16, 16,
2291 intrinsics::add_with_overflow,
2292 intrinsics::sub_with_overflow,
2293 intrinsics::mul_with_overflow }
2295 #[cfg(target_pointer_width = "32")]
2298 uint_impl! { usize, u32, 32,
2303 intrinsics::add_with_overflow,
2304 intrinsics::sub_with_overflow,
2305 intrinsics::mul_with_overflow }
2308 #[cfg(target_pointer_width = "64")]
2311 uint_impl! { usize, u64, 64,
2316 intrinsics::add_with_overflow,
2317 intrinsics::sub_with_overflow,
2318 intrinsics::mul_with_overflow }
2321 /// A classification of floating point numbers.
2323 /// This `enum` is used as the return type for [`f32::classify`] and [`f64::classify`]. See
2324 /// their documentation for more.
2326 /// [`f32::classify`]: ../../std/primitive.f32.html#method.classify
2327 /// [`f64::classify`]: ../../std/primitive.f64.html#method.classify
2332 /// use std::num::FpCategory;
2335 /// let num = 12.4_f32;
2336 /// let inf = f32::INFINITY;
2337 /// let zero = 0f32;
2338 /// let sub: f32 = 1.1754942e-38;
2339 /// let nan = f32::NAN;
2341 /// assert_eq!(num.classify(), FpCategory::Normal);
2342 /// assert_eq!(inf.classify(), FpCategory::Infinite);
2343 /// assert_eq!(zero.classify(), FpCategory::Zero);
2344 /// assert_eq!(nan.classify(), FpCategory::Nan);
2345 /// assert_eq!(sub.classify(), FpCategory::Subnormal);
2347 #[derive(Copy, Clone, PartialEq, Eq, Debug)]
2348 #[stable(feature = "rust1", since = "1.0.0")]
2349 pub enum FpCategory {
2350 /// "Not a Number", often obtained by dividing by zero.
2351 #[stable(feature = "rust1", since = "1.0.0")]
2354 /// Positive or negative infinity.
2355 #[stable(feature = "rust1", since = "1.0.0")]
2358 /// Positive or negative zero.
2359 #[stable(feature = "rust1", since = "1.0.0")]
2362 /// De-normalized floating point representation (less precise than `Normal`).
2363 #[stable(feature = "rust1", since = "1.0.0")]
2366 /// A regular floating point number.
2367 #[stable(feature = "rust1", since = "1.0.0")]
2371 /// A built-in floating point number.
2373 #[unstable(feature = "core_float",
2374 reason = "stable interface is via `impl f{32,64}` in later crates",
2376 pub trait Float: Sized {
2377 /// Returns `true` if this value is NaN and false otherwise.
2378 #[stable(feature = "core", since = "1.6.0")]
2379 fn is_nan(self) -> bool;
2380 /// Returns `true` if this value is positive infinity or negative infinity and
2381 /// false otherwise.
2382 #[stable(feature = "core", since = "1.6.0")]
2383 fn is_infinite(self) -> bool;
2384 /// Returns `true` if this number is neither infinite nor NaN.
2385 #[stable(feature = "core", since = "1.6.0")]
2386 fn is_finite(self) -> bool;
2387 /// Returns `true` if this number is neither zero, infinite, denormal, or NaN.
2388 #[stable(feature = "core", since = "1.6.0")]
2389 fn is_normal(self) -> bool;
2390 /// Returns the category that this number falls into.
2391 #[stable(feature = "core", since = "1.6.0")]
2392 fn classify(self) -> FpCategory;
2394 /// Computes the absolute value of `self`. Returns `Float::nan()` if the
2395 /// number is `Float::nan()`.
2396 #[stable(feature = "core", since = "1.6.0")]
2397 fn abs(self) -> Self;
2398 /// Returns a number that represents the sign of `self`.
2400 /// - `1.0` if the number is positive, `+0.0` or `Float::infinity()`
2401 /// - `-1.0` if the number is negative, `-0.0` or `Float::neg_infinity()`
2402 /// - `Float::nan()` if the number is `Float::nan()`
2403 #[stable(feature = "core", since = "1.6.0")]
2404 fn signum(self) -> Self;
2406 /// Returns `true` if `self` is positive, including `+0.0` and
2407 /// `Float::infinity()`.
2408 #[stable(feature = "core", since = "1.6.0")]
2409 fn is_sign_positive(self) -> bool;
2410 /// Returns `true` if `self` is negative, including `-0.0` and
2411 /// `Float::neg_infinity()`.
2412 #[stable(feature = "core", since = "1.6.0")]
2413 fn is_sign_negative(self) -> bool;
2415 /// Take the reciprocal (inverse) of a number, `1/x`.
2416 #[stable(feature = "core", since = "1.6.0")]
2417 fn recip(self) -> Self;
2419 /// Raise a number to an integer power.
2421 /// Using this function is generally faster than using `powf`
2422 #[stable(feature = "core", since = "1.6.0")]
2423 fn powi(self, n: i32) -> Self;
2425 /// Convert radians to degrees.
2426 #[stable(feature = "deg_rad_conversions", since="1.7.0")]
2427 fn to_degrees(self) -> Self;
2428 /// Convert degrees to radians.
2429 #[stable(feature = "deg_rad_conversions", since="1.7.0")]
2430 fn to_radians(self) -> Self;
2433 macro_rules! from_str_radix_int_impl {
2435 #[stable(feature = "rust1", since = "1.0.0")]
2436 impl FromStr for $t {
2437 type Err = ParseIntError;
2438 fn from_str(src: &str) -> Result<Self, ParseIntError> {
2439 from_str_radix(src, 10)
2444 from_str_radix_int_impl! { isize i8 i16 i32 i64 i128 usize u8 u16 u32 u64 u128 }
2446 /// The error type returned when a checked integral type conversion fails.
2447 #[unstable(feature = "try_from", issue = "33417")]
2448 #[derive(Debug, Copy, Clone)]
2449 pub struct TryFromIntError(());
2451 impl TryFromIntError {
2452 #[unstable(feature = "int_error_internals",
2453 reason = "available through Error trait and this method should \
2454 not be exposed publicly",
2457 pub fn __description(&self) -> &str {
2458 "out of range integral type conversion attempted"
2462 #[unstable(feature = "try_from", issue = "33417")]
2463 impl fmt::Display for TryFromIntError {
2464 fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
2465 self.__description().fmt(fmt)
2469 macro_rules! same_sign_try_from_int_impl {
2470 ($storage:ty, $target:ty, $($source:ty),*) => {$(
2471 #[unstable(feature = "try_from", issue = "33417")]
2472 impl TryFrom<$source> for $target {
2473 type Error = TryFromIntError;
2475 fn try_from(u: $source) -> Result<$target, TryFromIntError> {
2476 let min = <$target as FromStrRadixHelper>::min_value() as $storage;
2477 let max = <$target as FromStrRadixHelper>::max_value() as $storage;
2478 if u as $storage < min || u as $storage > max {
2479 Err(TryFromIntError(()))
2488 same_sign_try_from_int_impl!(u128, u8, u8, u16, u32, u64, u128, usize);
2489 same_sign_try_from_int_impl!(i128, i8, i8, i16, i32, i64, i128, isize);
2490 same_sign_try_from_int_impl!(u128, u16, u8, u16, u32, u64, u128, usize);
2491 same_sign_try_from_int_impl!(i128, i16, i8, i16, i32, i64, i128, isize);
2492 same_sign_try_from_int_impl!(u128, u32, u8, u16, u32, u64, u128, usize);
2493 same_sign_try_from_int_impl!(i128, i32, i8, i16, i32, i64, i128, isize);
2494 same_sign_try_from_int_impl!(u128, u64, u8, u16, u32, u64, u128, usize);
2495 same_sign_try_from_int_impl!(i128, i64, i8, i16, i32, i64, i128, isize);
2496 same_sign_try_from_int_impl!(u128, u128, u8, u16, u32, u64, u128, usize);
2497 same_sign_try_from_int_impl!(i128, i128, i8, i16, i32, i64, i128, isize);
2498 same_sign_try_from_int_impl!(u128, usize, u8, u16, u32, u64, u128, usize);
2499 same_sign_try_from_int_impl!(i128, isize, i8, i16, i32, i64, i128, isize);
2501 macro_rules! cross_sign_from_int_impl {
2502 ($unsigned:ty, $($signed:ty),*) => {$(
2503 #[unstable(feature = "try_from", issue = "33417")]
2504 impl TryFrom<$unsigned> for $signed {
2505 type Error = TryFromIntError;
2507 fn try_from(u: $unsigned) -> Result<$signed, TryFromIntError> {
2508 let max = <$signed as FromStrRadixHelper>::max_value() as u128;
2509 if u as u128 > max {
2510 Err(TryFromIntError(()))
2517 #[unstable(feature = "try_from", issue = "33417")]
2518 impl TryFrom<$signed> for $unsigned {
2519 type Error = TryFromIntError;
2521 fn try_from(u: $signed) -> Result<$unsigned, TryFromIntError> {
2522 let max = <$unsigned as FromStrRadixHelper>::max_value() as u128;
2523 if u < 0 || u as u128 > max {
2524 Err(TryFromIntError(()))
2533 cross_sign_from_int_impl!(u8, i8, i16, i32, i64, i128, isize);
2534 cross_sign_from_int_impl!(u16, i8, i16, i32, i64, i128, isize);
2535 cross_sign_from_int_impl!(u32, i8, i16, i32, i64, i128, isize);
2536 cross_sign_from_int_impl!(u64, i8, i16, i32, i64, i128, isize);
2537 cross_sign_from_int_impl!(u128, i8, i16, i32, i64, i128, isize);
2538 cross_sign_from_int_impl!(usize, i8, i16, i32, i64, i128, isize);
2541 trait FromStrRadixHelper: PartialOrd + Copy {
2542 fn min_value() -> Self;
2543 fn max_value() -> Self;
2544 fn from_u32(u: u32) -> Self;
2545 fn checked_mul(&self, other: u32) -> Option<Self>;
2546 fn checked_sub(&self, other: u32) -> Option<Self>;
2547 fn checked_add(&self, other: u32) -> Option<Self>;
2551 ($($t:ty)*) => ($(impl FromStrRadixHelper for $t {
2552 fn min_value() -> Self { Self::min_value() }
2553 fn max_value() -> Self { Self::max_value() }
2554 fn from_u32(u: u32) -> Self { u as Self }
2555 fn checked_mul(&self, other: u32) -> Option<Self> {
2556 Self::checked_mul(*self, other as Self)
2558 fn checked_sub(&self, other: u32) -> Option<Self> {
2559 Self::checked_sub(*self, other as Self)
2561 fn checked_add(&self, other: u32) -> Option<Self> {
2562 Self::checked_add(*self, other as Self)
2566 doit! { i8 i16 i32 i64 i128 isize u8 u16 u32 u64 u128 usize }
2568 fn from_str_radix<T: FromStrRadixHelper>(src: &str, radix: u32) -> Result<T, ParseIntError> {
2569 use self::IntErrorKind::*;
2570 use self::ParseIntError as PIE;
2572 assert!(radix >= 2 && radix <= 36,
2573 "from_str_radix_int: must lie in the range `[2, 36]` - found {}",
2577 return Err(PIE { kind: Empty });
2580 let is_signed_ty = T::from_u32(0) > T::min_value();
2582 // all valid digits are ascii, so we will just iterate over the utf8 bytes
2583 // and cast them to chars. .to_digit() will safely return None for anything
2584 // other than a valid ascii digit for the given radix, including the first-byte
2585 // of multi-byte sequences
2586 let src = src.as_bytes();
2588 let (is_positive, digits) = match src[0] {
2589 b'+' => (true, &src[1..]),
2590 b'-' if is_signed_ty => (false, &src[1..]),
2594 if digits.is_empty() {
2595 return Err(PIE { kind: Empty });
2598 let mut result = T::from_u32(0);
2600 // The number is positive
2602 let x = match (c as char).to_digit(radix) {
2604 None => return Err(PIE { kind: InvalidDigit }),
2606 result = match result.checked_mul(radix) {
2607 Some(result) => result,
2608 None => return Err(PIE { kind: Overflow }),
2610 result = match result.checked_add(x) {
2611 Some(result) => result,
2612 None => return Err(PIE { kind: Overflow }),
2616 // The number is negative
2618 let x = match (c as char).to_digit(radix) {
2620 None => return Err(PIE { kind: InvalidDigit }),
2622 result = match result.checked_mul(radix) {
2623 Some(result) => result,
2624 None => return Err(PIE { kind: Underflow }),
2626 result = match result.checked_sub(x) {
2627 Some(result) => result,
2628 None => return Err(PIE { kind: Underflow }),
2635 /// An error which can be returned when parsing an integer.
2637 /// This error is used as the error type for the `from_str_radix()` functions
2638 /// on the primitive integer types, such as [`i8::from_str_radix`].
2640 /// [`i8::from_str_radix`]: ../../std/primitive.i8.html#method.from_str_radix
2641 #[derive(Debug, Clone, PartialEq, Eq)]
2642 #[stable(feature = "rust1", since = "1.0.0")]
2643 pub struct ParseIntError {
2647 #[derive(Debug, Clone, PartialEq, Eq)]
2655 impl ParseIntError {
2656 #[unstable(feature = "int_error_internals",
2657 reason = "available through Error trait and this method should \
2658 not be exposed publicly",
2661 pub fn __description(&self) -> &str {
2663 IntErrorKind::Empty => "cannot parse integer from empty string",
2664 IntErrorKind::InvalidDigit => "invalid digit found in string",
2665 IntErrorKind::Overflow => "number too large to fit in target type",
2666 IntErrorKind::Underflow => "number too small to fit in target type",
2671 #[stable(feature = "rust1", since = "1.0.0")]
2672 impl fmt::Display for ParseIntError {
2673 fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
2674 self.__description().fmt(f)
2678 #[stable(feature = "rust1", since = "1.0.0")]
2679 pub use num::dec2flt::ParseFloatError;
2681 // Conversion traits for primitive integer and float types
2682 // Conversions T -> T are covered by a blanket impl and therefore excluded
2683 // Some conversions from and to usize/isize are not implemented due to portability concerns
2684 macro_rules! impl_from {
2685 ($Small: ty, $Large: ty, #[$attr:meta]) => {
2687 impl From<$Small> for $Large {
2689 fn from(small: $Small) -> $Large {
2696 // Unsigned -> Unsigned
2697 impl_from! { u8, u16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2698 impl_from! { u8, u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2699 impl_from! { u8, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2700 impl_from! { u8, u128, #[unstable(feature = "i128", issue = "35118")] }
2701 impl_from! { u8, usize, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2702 impl_from! { u16, u32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2703 impl_from! { u16, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2704 impl_from! { u16, u128, #[unstable(feature = "i128", issue = "35118")] }
2705 impl_from! { u32, u64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2706 impl_from! { u32, u128, #[unstable(feature = "i128", issue = "35118")] }
2707 impl_from! { u64, u128, #[unstable(feature = "i128", issue = "35118")] }
2710 impl_from! { i8, i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2711 impl_from! { i8, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2712 impl_from! { i8, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2713 impl_from! { i8, i128, #[unstable(feature = "i128", issue = "35118")] }
2714 impl_from! { i8, isize, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2715 impl_from! { i16, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2716 impl_from! { i16, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2717 impl_from! { i16, i128, #[unstable(feature = "i128", issue = "35118")] }
2718 impl_from! { i32, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2719 impl_from! { i32, i128, #[unstable(feature = "i128", issue = "35118")] }
2720 impl_from! { i64, i128, #[unstable(feature = "i128", issue = "35118")] }
2722 // Unsigned -> Signed
2723 impl_from! { u8, i16, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2724 impl_from! { u8, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2725 impl_from! { u8, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2726 impl_from! { u8, i128, #[unstable(feature = "i128", issue = "35118")] }
2727 impl_from! { u16, i32, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2728 impl_from! { u16, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2729 impl_from! { u16, i128, #[unstable(feature = "i128", issue = "35118")] }
2730 impl_from! { u32, i64, #[stable(feature = "lossless_int_conv", since = "1.5.0")] }
2731 impl_from! { u32, i128, #[unstable(feature = "i128", issue = "35118")] }
2732 impl_from! { u64, i128, #[unstable(feature = "i128", issue = "35118")] }
2734 // Note: integers can only be represented with full precision in a float if
2735 // they fit in the significand, which is 24 bits in f32 and 53 bits in f64.
2736 // Lossy float conversions are not implemented at this time.
2739 impl_from! { i8, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2740 impl_from! { i8, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2741 impl_from! { i16, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2742 impl_from! { i16, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2743 impl_from! { i32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2745 // Unsigned -> Float
2746 impl_from! { u8, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2747 impl_from! { u8, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2748 impl_from! { u16, f32, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2749 impl_from! { u16, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2750 impl_from! { u32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }
2753 impl_from! { f32, f64, #[stable(feature = "lossless_float_conv", since = "1.6.0")] }