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 generic mathematics
13 #![allow(missing_doc)]
16 use {int, i8, i16, i32, i64};
17 use {uint, u8, u16, u32, u64};
20 use cmp::{PartialEq, PartialOrd};
23 use ops::{Add, Sub, Mul, Div, Rem, Neg};
24 use ops::{Not, BitAnd, BitOr, BitXor, Shl, Shr};
25 use option::{Option, Some, None};
27 /// The base trait for numeric types
28 pub trait Num: PartialEq + Zero + One
36 macro_rules! trait_impl(
37 ($name:ident for $($t:ty)*) => ($(
42 trait_impl!(Num for uint u8 u16 u32 u64 int i8 i16 i32 i64 f32 f64)
44 /// Simultaneous division and remainder
46 pub fn div_rem<T: Div<T, T> + Rem<T, T>>(x: T, y: T) -> (T, T) {
50 /// Defines an additive identity element for `Self`.
54 /// This trait can be automatically be derived using `#[deriving(Zero)]`
55 /// attribute. If you choose to use this, make sure that the laws outlined in
56 /// the documentation for `Zero::zero` still hold.
57 pub trait Zero: Add<Self, Self> {
58 /// Returns the additive identity element of `Self`, `0`.
63 /// a + 0 = a ∀ a ∈ Self
64 /// 0 + a = a ∀ a ∈ Self
69 /// This function should return the same result at all times regardless of
70 /// external mutable state, for example values stored in TLS or in
72 // FIXME (#5527): This should be an associated constant
75 /// Returns `true` if `self` is equal to the additive identity.
76 fn is_zero(&self) -> bool;
79 macro_rules! zero_impl(
83 fn zero() -> $t { $v }
85 fn is_zero(&self) -> bool { *self == $v }
90 macro_rules! zero_float_impl(
94 fn zero() -> $t { $v }
97 fn is_zero(&self) -> bool { *self == $v || *self == -$v }
104 zero_impl!(u16, 0u16)
105 zero_impl!(u32, 0u32)
106 zero_impl!(u64, 0u64)
110 zero_impl!(i16, 0i16)
111 zero_impl!(i32, 0i32)
112 zero_impl!(i64, 0i64)
114 zero_float_impl!(f32, 0.0f32)
115 zero_float_impl!(f64, 0.0f64)
117 /// Returns the additive identity, `0`.
118 #[inline(always)] pub fn zero<T: Zero>() -> T { Zero::zero() }
120 /// Defines a multiplicative identity element for `Self`.
121 pub trait One: Mul<Self, Self> {
122 /// Returns the multiplicative identity element of `Self`, `1`.
127 /// a * 1 = a ∀ a ∈ Self
128 /// 1 * a = a ∀ a ∈ Self
133 /// This function should return the same result at all times regardless of
134 /// external mutable state, for example values stored in TLS or in
136 // FIXME (#5527): This should be an associated constant
140 macro_rules! one_impl(
141 ($t:ty, $v:expr) => {
144 fn one() -> $t { $v }
161 one_impl!(f32, 1.0f32)
162 one_impl!(f64, 1.0f64)
164 /// Returns the multiplicative identity, `1`.
165 #[inline(always)] pub fn one<T: One>() -> T { One::one() }
167 /// Useful functions for signed numbers (i.e. numbers that can be negative).
168 pub trait Signed: Num + Neg<Self> {
169 /// Computes the absolute value.
171 /// For `f32` and `f64`, `NaN` will be returned if the number is `NaN`.
172 fn abs(&self) -> Self;
174 /// The positive difference of two numbers.
176 /// Returns `zero` if the number is less than or equal to `other`, otherwise the difference
177 /// between `self` and `other` is returned.
178 fn abs_sub(&self, other: &Self) -> Self;
180 /// Returns the sign of the number.
182 /// For `f32` and `f64`:
184 /// * `1.0` if the number is positive, `+0.0` or `INFINITY`
185 /// * `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
186 /// * `NaN` if the number is `NaN`
190 /// * `0` if the number is zero
191 /// * `1` if the number is positive
192 /// * `-1` if the number is negative
193 fn signum(&self) -> Self;
195 /// Returns true if the number is positive and false if the number is zero or negative.
196 fn is_positive(&self) -> bool;
198 /// Returns true if the number is negative and false if the number is zero or positive.
199 fn is_negative(&self) -> bool;
202 macro_rules! signed_impl(
206 fn abs(&self) -> $t {
207 if self.is_negative() { -*self } else { *self }
211 fn abs_sub(&self, other: &$t) -> $t {
212 if *self <= *other { 0 } else { *self - *other }
216 fn signum(&self) -> $t {
225 fn is_positive(&self) -> bool { *self > 0 }
228 fn is_negative(&self) -> bool { *self < 0 }
233 signed_impl!(int i8 i16 i32 i64)
235 macro_rules! signed_float_impl(
236 ($t:ty, $nan:expr, $inf:expr, $neg_inf:expr, $fabs:path, $fcopysign:path, $fdim:ident) => {
238 /// Computes the absolute value. Returns `NAN` if the number is `NAN`.
240 fn abs(&self) -> $t {
241 unsafe { $fabs(*self) }
244 /// The positive difference of two numbers. Returns `0.0` if the number is
245 /// less than or equal to `other`, otherwise the difference between`self`
246 /// and `other` is returned.
248 fn abs_sub(&self, other: &$t) -> $t {
249 extern { fn $fdim(a: $t, b: $t) -> $t; }
250 unsafe { $fdim(*self, *other) }
255 /// - `1.0` if the number is positive, `+0.0` or `INFINITY`
256 /// - `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
257 /// - `NAN` if the number is NaN
259 fn signum(&self) -> $t {
260 if self != self { $nan } else {
261 unsafe { $fcopysign(1.0, *self) }
265 /// Returns `true` if the number is positive, including `+0.0` and `INFINITY`
267 fn is_positive(&self) -> bool { *self > 0.0 || (1.0 / *self) == $inf }
269 /// Returns `true` if the number is negative, including `-0.0` and `NEG_INFINITY`
271 fn is_negative(&self) -> bool { *self < 0.0 || (1.0 / *self) == $neg_inf }
276 signed_float_impl!(f32, f32::NAN, f32::INFINITY, f32::NEG_INFINITY,
277 intrinsics::fabsf32, intrinsics::copysignf32, fdimf)
278 signed_float_impl!(f64, f64::NAN, f64::INFINITY, f64::NEG_INFINITY,
279 intrinsics::fabsf64, intrinsics::copysignf64, fdim)
281 /// Computes the absolute value.
283 /// For `f32` and `f64`, `NaN` will be returned if the number is `NaN`
285 pub fn abs<T: Signed>(value: T) -> T {
289 /// The positive difference of two numbers.
291 /// Returns `zero` if the number is less than or equal to `other`,
292 /// otherwise the difference between `self` and `other` is returned.
294 pub fn abs_sub<T: Signed>(x: T, y: T) -> T {
298 /// Returns the sign of the number.
300 /// For `f32` and `f64`:
302 /// * `1.0` if the number is positive, `+0.0` or `INFINITY`
303 /// * `-1.0` if the number is negative, `-0.0` or `NEG_INFINITY`
304 /// * `NaN` if the number is `NaN`
308 /// * `0` if the number is zero
309 /// * `1` if the number is positive
310 /// * `-1` if the number is negative
311 #[inline(always)] pub fn signum<T: Signed>(value: T) -> T { value.signum() }
313 /// A trait for values which cannot be negative
314 pub trait Unsigned: Num {}
316 trait_impl!(Unsigned for uint u8 u16 u32 u64)
318 /// Raises a value to the power of exp, using exponentiation by squaring.
325 /// assert_eq!(num::pow(2, 4), 16);
328 pub fn pow<T: One + Mul<T, T>>(mut base: T, mut exp: uint) -> T {
331 let mut acc = one::<T>();
343 /// Numbers which have upper and lower bounds
345 // FIXME (#5527): These should be associated constants
346 /// returns the smallest finite number this type can represent
347 fn min_value() -> Self;
348 /// returns the largest finite number this type can represent
349 fn max_value() -> Self;
352 macro_rules! bounded_impl(
353 ($t:ty, $min:expr, $max:expr) => {
354 impl Bounded for $t {
356 fn min_value() -> $t { $min }
359 fn max_value() -> $t { $max }
364 bounded_impl!(uint, uint::MIN, uint::MAX)
365 bounded_impl!(u8, u8::MIN, u8::MAX)
366 bounded_impl!(u16, u16::MIN, u16::MAX)
367 bounded_impl!(u32, u32::MIN, u32::MAX)
368 bounded_impl!(u64, u64::MIN, u64::MAX)
370 bounded_impl!(int, int::MIN, int::MAX)
371 bounded_impl!(i8, i8::MIN, i8::MAX)
372 bounded_impl!(i16, i16::MIN, i16::MAX)
373 bounded_impl!(i32, i32::MIN, i32::MAX)
374 bounded_impl!(i64, i64::MIN, i64::MAX)
376 bounded_impl!(f32, f32::MIN_VALUE, f32::MAX_VALUE)
377 bounded_impl!(f64, f64::MIN_VALUE, f64::MAX_VALUE)
379 /// Numbers with a fixed binary representation.
380 pub trait Bitwise: Bounded
387 /// Returns the number of ones in the binary representation of the number.
392 /// use std::num::Bitwise;
394 /// let n = 0b01001100u8;
395 /// assert_eq!(n.count_ones(), 3);
397 fn count_ones(&self) -> Self;
399 /// Returns the number of zeros in the binary representation of the number.
404 /// use std::num::Bitwise;
406 /// let n = 0b01001100u8;
407 /// assert_eq!(n.count_zeros(), 5);
410 fn count_zeros(&self) -> Self {
411 (!*self).count_ones()
414 /// Returns the number of leading zeros in the in the binary representation
420 /// use std::num::Bitwise;
422 /// let n = 0b0101000u16;
423 /// assert_eq!(n.leading_zeros(), 10);
425 fn leading_zeros(&self) -> Self;
427 /// Returns the number of trailing zeros in the in the binary representation
433 /// use std::num::Bitwise;
435 /// let n = 0b0101000u16;
436 /// assert_eq!(n.trailing_zeros(), 3);
438 fn trailing_zeros(&self) -> Self;
440 /// Reverses the byte order of a binary number.
445 /// use std::num::Bitwise;
447 /// let n = 0x0123456789ABCDEFu64;
448 /// let m = 0xEFCDAB8967452301u64;
449 /// assert_eq!(n.swap_bytes(), m);
451 fn swap_bytes(&self) -> Self;
453 /// Shifts the bits to the left by a specified amount amount, `r`, wrapping
454 /// the truncated bits to the end of the resulting value.
459 /// use std::num::Bitwise;
461 /// let n = 0x0123456789ABCDEFu64;
462 /// let m = 0x3456789ABCDEF012u64;
463 /// assert_eq!(n.rotate_left(12), m);
465 fn rotate_left(&self, r: uint) -> Self;
467 /// Shifts the bits to the right by a specified amount amount, `r`, wrapping
468 /// the truncated bits to the beginning of the resulting value.
473 /// use std::num::Bitwise;
475 /// let n = 0x0123456789ABCDEFu64;
476 /// let m = 0xDEF0123456789ABCu64;
477 /// assert_eq!(n.rotate_right(12), m);
479 fn rotate_right(&self, r: uint) -> Self;
482 /// Swapping a single byte does nothing. This is unsafe to be consistent with
483 /// the other `bswap` intrinsics.
485 unsafe fn bswap8(x: u8) -> u8 { x }
487 macro_rules! bitwise_impl(
488 ($t:ty, $bits:expr, $co:ident, $lz:ident, $tz:ident, $bs:path) => {
489 impl Bitwise for $t {
491 fn count_ones(&self) -> $t { unsafe { intrinsics::$co(*self) } }
494 fn leading_zeros(&self) -> $t { unsafe { intrinsics::$lz(*self) } }
497 fn trailing_zeros(&self) -> $t { unsafe { intrinsics::$tz(*self) } }
500 fn swap_bytes(&self) -> $t { unsafe { $bs(*self) } }
503 fn rotate_left(&self, r: uint) -> $t {
504 // Protect against undefined behaviour for overlong bit shifts
506 (*self << r) | (*self >> ($bits - r))
510 fn rotate_right(&self, r: uint) -> $t {
511 // Protect against undefined behaviour for overlong bit shifts
513 (*self >> r) | (*self << ($bits - r))
519 macro_rules! bitwise_cast_impl(
520 ($t:ty, $t_cast:ty, $bits:expr, $co:ident, $lz:ident, $tz:ident, $bs:path) => {
521 impl Bitwise for $t {
523 fn count_ones(&self) -> $t { unsafe { intrinsics::$co(*self as $t_cast) as $t } }
526 fn leading_zeros(&self) -> $t { unsafe { intrinsics::$lz(*self as $t_cast) as $t } }
529 fn trailing_zeros(&self) -> $t { unsafe { intrinsics::$tz(*self as $t_cast) as $t } }
532 fn swap_bytes(&self) -> $t { unsafe { $bs(*self as $t_cast) as $t } }
535 fn rotate_left(&self, r: uint) -> $t {
536 // cast to prevent the sign bit from being corrupted
537 (*self as $t_cast).rotate_left(r) as $t
541 fn rotate_right(&self, r: uint) -> $t {
542 // cast to prevent the sign bit from being corrupted
543 (*self as $t_cast).rotate_right(r) as $t
549 #[cfg(target_word_size = "32")]
550 bitwise_cast_impl!(uint, u32, 32, ctpop32, ctlz32, cttz32, intrinsics::bswap32)
551 #[cfg(target_word_size = "64")]
552 bitwise_cast_impl!(uint, u64, 64, ctpop64, ctlz64, cttz64, intrinsics::bswap64)
554 bitwise_impl!(u8, 8, ctpop8, ctlz8, cttz8, bswap8)
555 bitwise_impl!(u16, 16, ctpop16, ctlz16, cttz16, intrinsics::bswap16)
556 bitwise_impl!(u32, 32, ctpop32, ctlz32, cttz32, intrinsics::bswap32)
557 bitwise_impl!(u64, 64, ctpop64, ctlz64, cttz64, intrinsics::bswap64)
559 #[cfg(target_word_size = "32")]
560 bitwise_cast_impl!(int, u32, 32, ctpop32, ctlz32, cttz32, intrinsics::bswap32)
561 #[cfg(target_word_size = "64")]
562 bitwise_cast_impl!(int, u64, 64, ctpop64, ctlz64, cttz64, intrinsics::bswap64)
564 bitwise_cast_impl!(i8, u8, 8, ctpop8, ctlz8, cttz8, bswap8)
565 bitwise_cast_impl!(i16, u16, 16, ctpop16, ctlz16, cttz16, intrinsics::bswap16)
566 bitwise_cast_impl!(i32, u32, 32, ctpop32, ctlz32, cttz32, intrinsics::bswap32)
567 bitwise_cast_impl!(i64, u64, 64, ctpop64, ctlz64, cttz64, intrinsics::bswap64)
569 /// Specifies the available operations common to all of Rust's core numeric primitives.
570 /// These may not always make sense from a purely mathematical point of view, but
571 /// may be useful for systems programming.
572 pub trait Primitive: Copy
579 trait_impl!(Primitive for uint u8 u16 u32 u64 int i8 i16 i32 i64 f32 f64)
581 /// A collection of traits relevant to primitive signed and unsigned integers
582 pub trait Int: Primitive
589 trait_impl!(Int for uint u8 u16 u32 u64 int i8 i16 i32 i64)
591 /// Returns the smallest power of 2 greater than or equal to `n`.
593 pub fn next_power_of_two<T: Unsigned + Int>(n: T) -> T {
594 let halfbits: T = cast(size_of::<T>() * 4).unwrap();
595 let mut tmp: T = n - one();
596 let mut shift: T = one();
597 while shift <= halfbits {
598 tmp = tmp | (tmp >> shift);
599 shift = shift << one();
604 // Returns `true` iff `n == 2^k` for some k.
606 pub fn is_power_of_two<T: Unsigned + Int>(n: T) -> bool {
607 (n - one()) & n == zero()
610 /// Returns the smallest power of 2 greater than or equal to `n`. If the next
611 /// power of two is greater than the type's maximum value, `None` is returned,
612 /// otherwise the power of 2 is wrapped in `Some`.
614 pub fn checked_next_power_of_two<T: Unsigned + Int>(n: T) -> Option<T> {
615 let halfbits: T = cast(size_of::<T>() * 4).unwrap();
616 let mut tmp: T = n - one();
617 let mut shift: T = one();
618 while shift <= halfbits {
619 tmp = tmp | (tmp >> shift);
620 shift = shift << one();
622 tmp.checked_add(&one())
625 /// A generic trait for converting a value to a number.
626 pub trait ToPrimitive {
627 /// Converts the value of `self` to an `int`.
629 fn to_int(&self) -> Option<int> {
630 self.to_i64().and_then(|x| x.to_int())
633 /// Converts the value of `self` to an `i8`.
635 fn to_i8(&self) -> Option<i8> {
636 self.to_i64().and_then(|x| x.to_i8())
639 /// Converts the value of `self` to an `i16`.
641 fn to_i16(&self) -> Option<i16> {
642 self.to_i64().and_then(|x| x.to_i16())
645 /// Converts the value of `self` to an `i32`.
647 fn to_i32(&self) -> Option<i32> {
648 self.to_i64().and_then(|x| x.to_i32())
651 /// Converts the value of `self` to an `i64`.
652 fn to_i64(&self) -> Option<i64>;
654 /// Converts the value of `self` to an `uint`.
656 fn to_uint(&self) -> Option<uint> {
657 self.to_u64().and_then(|x| x.to_uint())
660 /// Converts the value of `self` to an `u8`.
662 fn to_u8(&self) -> Option<u8> {
663 self.to_u64().and_then(|x| x.to_u8())
666 /// Converts the value of `self` to an `u16`.
668 fn to_u16(&self) -> Option<u16> {
669 self.to_u64().and_then(|x| x.to_u16())
672 /// Converts the value of `self` to an `u32`.
674 fn to_u32(&self) -> Option<u32> {
675 self.to_u64().and_then(|x| x.to_u32())
678 /// Converts the value of `self` to an `u64`.
680 fn to_u64(&self) -> Option<u64>;
682 /// Converts the value of `self` to an `f32`.
684 fn to_f32(&self) -> Option<f32> {
685 self.to_f64().and_then(|x| x.to_f32())
688 /// Converts the value of `self` to an `f64`.
690 fn to_f64(&self) -> Option<f64> {
691 self.to_i64().and_then(|x| x.to_f64())
695 macro_rules! impl_to_primitive_int_to_int(
696 ($SrcT:ty, $DstT:ty) => (
698 if size_of::<$SrcT>() <= size_of::<$DstT>() {
701 let n = *self as i64;
702 let min_value: $DstT = Bounded::min_value();
703 let max_value: $DstT = Bounded::max_value();
704 if min_value as i64 <= n && n <= max_value as i64 {
714 macro_rules! impl_to_primitive_int_to_uint(
715 ($SrcT:ty, $DstT:ty) => (
717 let zero: $SrcT = Zero::zero();
718 let max_value: $DstT = Bounded::max_value();
719 if zero <= *self && *self as u64 <= max_value as u64 {
728 macro_rules! impl_to_primitive_int(
730 impl ToPrimitive for $T {
732 fn to_int(&self) -> Option<int> { impl_to_primitive_int_to_int!($T, int) }
734 fn to_i8(&self) -> Option<i8> { impl_to_primitive_int_to_int!($T, i8) }
736 fn to_i16(&self) -> Option<i16> { impl_to_primitive_int_to_int!($T, i16) }
738 fn to_i32(&self) -> Option<i32> { impl_to_primitive_int_to_int!($T, i32) }
740 fn to_i64(&self) -> Option<i64> { impl_to_primitive_int_to_int!($T, i64) }
743 fn to_uint(&self) -> Option<uint> { impl_to_primitive_int_to_uint!($T, uint) }
745 fn to_u8(&self) -> Option<u8> { impl_to_primitive_int_to_uint!($T, u8) }
747 fn to_u16(&self) -> Option<u16> { impl_to_primitive_int_to_uint!($T, u16) }
749 fn to_u32(&self) -> Option<u32> { impl_to_primitive_int_to_uint!($T, u32) }
751 fn to_u64(&self) -> Option<u64> { impl_to_primitive_int_to_uint!($T, u64) }
754 fn to_f32(&self) -> Option<f32> { Some(*self as f32) }
756 fn to_f64(&self) -> Option<f64> { Some(*self as f64) }
761 impl_to_primitive_int!(int)
762 impl_to_primitive_int!(i8)
763 impl_to_primitive_int!(i16)
764 impl_to_primitive_int!(i32)
765 impl_to_primitive_int!(i64)
767 macro_rules! impl_to_primitive_uint_to_int(
770 let max_value: $DstT = Bounded::max_value();
771 if *self as u64 <= max_value as u64 {
780 macro_rules! impl_to_primitive_uint_to_uint(
781 ($SrcT:ty, $DstT:ty) => (
783 if size_of::<$SrcT>() <= size_of::<$DstT>() {
786 let zero: $SrcT = Zero::zero();
787 let max_value: $DstT = Bounded::max_value();
788 if zero <= *self && *self as u64 <= max_value as u64 {
798 macro_rules! impl_to_primitive_uint(
800 impl ToPrimitive for $T {
802 fn to_int(&self) -> Option<int> { impl_to_primitive_uint_to_int!(int) }
804 fn to_i8(&self) -> Option<i8> { impl_to_primitive_uint_to_int!(i8) }
806 fn to_i16(&self) -> Option<i16> { impl_to_primitive_uint_to_int!(i16) }
808 fn to_i32(&self) -> Option<i32> { impl_to_primitive_uint_to_int!(i32) }
810 fn to_i64(&self) -> Option<i64> { impl_to_primitive_uint_to_int!(i64) }
813 fn to_uint(&self) -> Option<uint> { impl_to_primitive_uint_to_uint!($T, uint) }
815 fn to_u8(&self) -> Option<u8> { impl_to_primitive_uint_to_uint!($T, u8) }
817 fn to_u16(&self) -> Option<u16> { impl_to_primitive_uint_to_uint!($T, u16) }
819 fn to_u32(&self) -> Option<u32> { impl_to_primitive_uint_to_uint!($T, u32) }
821 fn to_u64(&self) -> Option<u64> { impl_to_primitive_uint_to_uint!($T, u64) }
824 fn to_f32(&self) -> Option<f32> { Some(*self as f32) }
826 fn to_f64(&self) -> Option<f64> { Some(*self as f64) }
831 impl_to_primitive_uint!(uint)
832 impl_to_primitive_uint!(u8)
833 impl_to_primitive_uint!(u16)
834 impl_to_primitive_uint!(u32)
835 impl_to_primitive_uint!(u64)
837 macro_rules! impl_to_primitive_float_to_float(
838 ($SrcT:ty, $DstT:ty) => (
839 if size_of::<$SrcT>() <= size_of::<$DstT>() {
842 let n = *self as f64;
843 let max_value: $SrcT = Bounded::max_value();
844 if -max_value as f64 <= n && n <= max_value as f64 {
853 macro_rules! impl_to_primitive_float(
855 impl ToPrimitive for $T {
857 fn to_int(&self) -> Option<int> { Some(*self as int) }
859 fn to_i8(&self) -> Option<i8> { Some(*self as i8) }
861 fn to_i16(&self) -> Option<i16> { Some(*self as i16) }
863 fn to_i32(&self) -> Option<i32> { Some(*self as i32) }
865 fn to_i64(&self) -> Option<i64> { Some(*self as i64) }
868 fn to_uint(&self) -> Option<uint> { Some(*self as uint) }
870 fn to_u8(&self) -> Option<u8> { Some(*self as u8) }
872 fn to_u16(&self) -> Option<u16> { Some(*self as u16) }
874 fn to_u32(&self) -> Option<u32> { Some(*self as u32) }
876 fn to_u64(&self) -> Option<u64> { Some(*self as u64) }
879 fn to_f32(&self) -> Option<f32> { impl_to_primitive_float_to_float!($T, f32) }
881 fn to_f64(&self) -> Option<f64> { impl_to_primitive_float_to_float!($T, f64) }
886 impl_to_primitive_float!(f32)
887 impl_to_primitive_float!(f64)
889 /// A generic trait for converting a number to a value.
890 pub trait FromPrimitive {
891 /// Convert an `int` to return an optional value of this type. If the
892 /// value cannot be represented by this value, the `None` is returned.
894 fn from_int(n: int) -> Option<Self> {
895 FromPrimitive::from_i64(n as i64)
898 /// Convert an `i8` to return an optional value of this type. If the
899 /// type cannot be represented by this value, the `None` is returned.
901 fn from_i8(n: i8) -> Option<Self> {
902 FromPrimitive::from_i64(n as i64)
905 /// Convert an `i16` to return an optional value of this type. If the
906 /// type cannot be represented by this value, the `None` is returned.
908 fn from_i16(n: i16) -> Option<Self> {
909 FromPrimitive::from_i64(n as i64)
912 /// Convert an `i32` to return an optional value of this type. If the
913 /// type cannot be represented by this value, the `None` is returned.
915 fn from_i32(n: i32) -> Option<Self> {
916 FromPrimitive::from_i64(n as i64)
919 /// Convert an `i64` to return an optional value of this type. If the
920 /// type cannot be represented by this value, the `None` is returned.
921 fn from_i64(n: i64) -> Option<Self>;
923 /// Convert an `uint` to return an optional value of this type. If the
924 /// type cannot be represented by this value, the `None` is returned.
926 fn from_uint(n: uint) -> Option<Self> {
927 FromPrimitive::from_u64(n as u64)
930 /// Convert an `u8` to return an optional value of this type. If the
931 /// type cannot be represented by this value, the `None` is returned.
933 fn from_u8(n: u8) -> Option<Self> {
934 FromPrimitive::from_u64(n as u64)
937 /// Convert an `u16` to return an optional value of this type. If the
938 /// type cannot be represented by this value, the `None` is returned.
940 fn from_u16(n: u16) -> Option<Self> {
941 FromPrimitive::from_u64(n as u64)
944 /// Convert an `u32` to return an optional value of this type. If the
945 /// type cannot be represented by this value, the `None` is returned.
947 fn from_u32(n: u32) -> Option<Self> {
948 FromPrimitive::from_u64(n as u64)
951 /// Convert an `u64` to return an optional value of this type. If the
952 /// type cannot be represented by this value, the `None` is returned.
953 fn from_u64(n: u64) -> Option<Self>;
955 /// Convert a `f32` to return an optional value of this type. If the
956 /// type cannot be represented by this value, the `None` is returned.
958 fn from_f32(n: f32) -> Option<Self> {
959 FromPrimitive::from_f64(n as f64)
962 /// Convert a `f64` to return an optional value of this type. If the
963 /// type cannot be represented by this value, the `None` is returned.
965 fn from_f64(n: f64) -> Option<Self> {
966 FromPrimitive::from_i64(n as i64)
970 /// A utility function that just calls `FromPrimitive::from_int`.
971 pub fn from_int<A: FromPrimitive>(n: int) -> Option<A> {
972 FromPrimitive::from_int(n)
975 /// A utility function that just calls `FromPrimitive::from_i8`.
976 pub fn from_i8<A: FromPrimitive>(n: i8) -> Option<A> {
977 FromPrimitive::from_i8(n)
980 /// A utility function that just calls `FromPrimitive::from_i16`.
981 pub fn from_i16<A: FromPrimitive>(n: i16) -> Option<A> {
982 FromPrimitive::from_i16(n)
985 /// A utility function that just calls `FromPrimitive::from_i32`.
986 pub fn from_i32<A: FromPrimitive>(n: i32) -> Option<A> {
987 FromPrimitive::from_i32(n)
990 /// A utility function that just calls `FromPrimitive::from_i64`.
991 pub fn from_i64<A: FromPrimitive>(n: i64) -> Option<A> {
992 FromPrimitive::from_i64(n)
995 /// A utility function that just calls `FromPrimitive::from_uint`.
996 pub fn from_uint<A: FromPrimitive>(n: uint) -> Option<A> {
997 FromPrimitive::from_uint(n)
1000 /// A utility function that just calls `FromPrimitive::from_u8`.
1001 pub fn from_u8<A: FromPrimitive>(n: u8) -> Option<A> {
1002 FromPrimitive::from_u8(n)
1005 /// A utility function that just calls `FromPrimitive::from_u16`.
1006 pub fn from_u16<A: FromPrimitive>(n: u16) -> Option<A> {
1007 FromPrimitive::from_u16(n)
1010 /// A utility function that just calls `FromPrimitive::from_u32`.
1011 pub fn from_u32<A: FromPrimitive>(n: u32) -> Option<A> {
1012 FromPrimitive::from_u32(n)
1015 /// A utility function that just calls `FromPrimitive::from_u64`.
1016 pub fn from_u64<A: FromPrimitive>(n: u64) -> Option<A> {
1017 FromPrimitive::from_u64(n)
1020 /// A utility function that just calls `FromPrimitive::from_f32`.
1021 pub fn from_f32<A: FromPrimitive>(n: f32) -> Option<A> {
1022 FromPrimitive::from_f32(n)
1025 /// A utility function that just calls `FromPrimitive::from_f64`.
1026 pub fn from_f64<A: FromPrimitive>(n: f64) -> Option<A> {
1027 FromPrimitive::from_f64(n)
1030 macro_rules! impl_from_primitive(
1031 ($T:ty, $to_ty:expr) => (
1032 impl FromPrimitive for $T {
1033 #[inline] fn from_int(n: int) -> Option<$T> { $to_ty }
1034 #[inline] fn from_i8(n: i8) -> Option<$T> { $to_ty }
1035 #[inline] fn from_i16(n: i16) -> Option<$T> { $to_ty }
1036 #[inline] fn from_i32(n: i32) -> Option<$T> { $to_ty }
1037 #[inline] fn from_i64(n: i64) -> Option<$T> { $to_ty }
1039 #[inline] fn from_uint(n: uint) -> Option<$T> { $to_ty }
1040 #[inline] fn from_u8(n: u8) -> Option<$T> { $to_ty }
1041 #[inline] fn from_u16(n: u16) -> Option<$T> { $to_ty }
1042 #[inline] fn from_u32(n: u32) -> Option<$T> { $to_ty }
1043 #[inline] fn from_u64(n: u64) -> Option<$T> { $to_ty }
1045 #[inline] fn from_f32(n: f32) -> Option<$T> { $to_ty }
1046 #[inline] fn from_f64(n: f64) -> Option<$T> { $to_ty }
1051 impl_from_primitive!(int, n.to_int())
1052 impl_from_primitive!(i8, n.to_i8())
1053 impl_from_primitive!(i16, n.to_i16())
1054 impl_from_primitive!(i32, n.to_i32())
1055 impl_from_primitive!(i64, n.to_i64())
1056 impl_from_primitive!(uint, n.to_uint())
1057 impl_from_primitive!(u8, n.to_u8())
1058 impl_from_primitive!(u16, n.to_u16())
1059 impl_from_primitive!(u32, n.to_u32())
1060 impl_from_primitive!(u64, n.to_u64())
1061 impl_from_primitive!(f32, n.to_f32())
1062 impl_from_primitive!(f64, n.to_f64())
1064 /// Cast from one machine scalar to another.
1071 /// let twenty: f32 = num::cast(0x14).unwrap();
1072 /// assert_eq!(twenty, 20f32);
1076 pub fn cast<T: NumCast,U: NumCast>(n: T) -> Option<U> {
1080 /// An interface for casting between machine scalars.
1081 pub trait NumCast: ToPrimitive {
1082 /// Creates a number from another value that can be converted into a primitive via the
1083 /// `ToPrimitive` trait.
1084 fn from<T: ToPrimitive>(n: T) -> Option<Self>;
1087 macro_rules! impl_num_cast(
1088 ($T:ty, $conv:ident) => (
1089 impl NumCast for $T {
1091 fn from<N: ToPrimitive>(n: N) -> Option<$T> {
1092 // `$conv` could be generated using `concat_idents!`, but that
1093 // macro seems to be broken at the moment
1100 impl_num_cast!(u8, to_u8)
1101 impl_num_cast!(u16, to_u16)
1102 impl_num_cast!(u32, to_u32)
1103 impl_num_cast!(u64, to_u64)
1104 impl_num_cast!(uint, to_uint)
1105 impl_num_cast!(i8, to_i8)
1106 impl_num_cast!(i16, to_i16)
1107 impl_num_cast!(i32, to_i32)
1108 impl_num_cast!(i64, to_i64)
1109 impl_num_cast!(int, to_int)
1110 impl_num_cast!(f32, to_f32)
1111 impl_num_cast!(f64, to_f64)
1113 /// Saturating math operations
1114 pub trait Saturating {
1115 /// Saturating addition operator.
1116 /// Returns a+b, saturating at the numeric bounds instead of overflowing.
1117 fn saturating_add(self, v: Self) -> Self;
1119 /// Saturating subtraction operator.
1120 /// Returns a-b, saturating at the numeric bounds instead of overflowing.
1121 fn saturating_sub(self, v: Self) -> Self;
1124 impl<T: CheckedAdd + CheckedSub + Zero + PartialOrd + Bounded> Saturating for T {
1126 fn saturating_add(self, v: T) -> T {
1127 match self.checked_add(&v) {
1129 None => if v >= Zero::zero() {
1130 Bounded::max_value()
1132 Bounded::min_value()
1138 fn saturating_sub(self, v: T) -> T {
1139 match self.checked_sub(&v) {
1141 None => if v >= Zero::zero() {
1142 Bounded::min_value()
1144 Bounded::max_value()
1150 /// Performs addition that returns `None` instead of wrapping around on overflow.
1151 pub trait CheckedAdd: Add<Self, Self> {
1152 /// Adds two numbers, checking for overflow. If overflow happens, `None` is returned.
1153 fn checked_add(&self, v: &Self) -> Option<Self>;
1156 macro_rules! checked_impl(
1157 ($trait_name:ident, $method:ident, $t:ty, $op:path) => {
1158 impl $trait_name for $t {
1160 fn $method(&self, v: &$t) -> Option<$t> {
1162 let (x, y) = $op(*self, *v);
1163 if y { None } else { Some(x) }
1169 macro_rules! checked_cast_impl(
1170 ($trait_name:ident, $method:ident, $t:ty, $cast:ty, $op:path) => {
1171 impl $trait_name for $t {
1173 fn $method(&self, v: &$t) -> Option<$t> {
1175 let (x, y) = $op(*self as $cast, *v as $cast);
1176 if y { None } else { Some(x as $t) }
1183 #[cfg(target_word_size = "32")]
1184 checked_cast_impl!(CheckedAdd, checked_add, uint, u32, intrinsics::u32_add_with_overflow)
1185 #[cfg(target_word_size = "64")]
1186 checked_cast_impl!(CheckedAdd, checked_add, uint, u64, intrinsics::u64_add_with_overflow)
1188 checked_impl!(CheckedAdd, checked_add, u8, intrinsics::u8_add_with_overflow)
1189 checked_impl!(CheckedAdd, checked_add, u16, intrinsics::u16_add_with_overflow)
1190 checked_impl!(CheckedAdd, checked_add, u32, intrinsics::u32_add_with_overflow)
1191 checked_impl!(CheckedAdd, checked_add, u64, intrinsics::u64_add_with_overflow)
1193 #[cfg(target_word_size = "32")]
1194 checked_cast_impl!(CheckedAdd, checked_add, int, i32, intrinsics::i32_add_with_overflow)
1195 #[cfg(target_word_size = "64")]
1196 checked_cast_impl!(CheckedAdd, checked_add, int, i64, intrinsics::i64_add_with_overflow)
1198 checked_impl!(CheckedAdd, checked_add, i8, intrinsics::i8_add_with_overflow)
1199 checked_impl!(CheckedAdd, checked_add, i16, intrinsics::i16_add_with_overflow)
1200 checked_impl!(CheckedAdd, checked_add, i32, intrinsics::i32_add_with_overflow)
1201 checked_impl!(CheckedAdd, checked_add, i64, intrinsics::i64_add_with_overflow)
1203 /// Performs subtraction that returns `None` instead of wrapping around on underflow.
1204 pub trait CheckedSub: Sub<Self, Self> {
1205 /// Subtracts two numbers, checking for underflow. If underflow happens, `None` is returned.
1206 fn checked_sub(&self, v: &Self) -> Option<Self>;
1209 #[cfg(target_word_size = "32")]
1210 checked_cast_impl!(CheckedSub, checked_sub, uint, u32, intrinsics::u32_sub_with_overflow)
1211 #[cfg(target_word_size = "64")]
1212 checked_cast_impl!(CheckedSub, checked_sub, uint, u64, intrinsics::u64_sub_with_overflow)
1214 checked_impl!(CheckedSub, checked_sub, u8, intrinsics::u8_sub_with_overflow)
1215 checked_impl!(CheckedSub, checked_sub, u16, intrinsics::u16_sub_with_overflow)
1216 checked_impl!(CheckedSub, checked_sub, u32, intrinsics::u32_sub_with_overflow)
1217 checked_impl!(CheckedSub, checked_sub, u64, intrinsics::u64_sub_with_overflow)
1219 #[cfg(target_word_size = "32")]
1220 checked_cast_impl!(CheckedSub, checked_sub, int, i32, intrinsics::i32_sub_with_overflow)
1221 #[cfg(target_word_size = "64")]
1222 checked_cast_impl!(CheckedSub, checked_sub, int, i64, intrinsics::i64_sub_with_overflow)
1224 checked_impl!(CheckedSub, checked_sub, i8, intrinsics::i8_sub_with_overflow)
1225 checked_impl!(CheckedSub, checked_sub, i16, intrinsics::i16_sub_with_overflow)
1226 checked_impl!(CheckedSub, checked_sub, i32, intrinsics::i32_sub_with_overflow)
1227 checked_impl!(CheckedSub, checked_sub, i64, intrinsics::i64_sub_with_overflow)
1229 /// Performs multiplication that returns `None` instead of wrapping around on underflow or
1231 pub trait CheckedMul: Mul<Self, Self> {
1232 /// Multiplies two numbers, checking for underflow or overflow. If underflow or overflow
1233 /// happens, `None` is returned.
1234 fn checked_mul(&self, v: &Self) -> Option<Self>;
1237 #[cfg(target_word_size = "32")]
1238 checked_cast_impl!(CheckedMul, checked_mul, uint, u32, intrinsics::u32_mul_with_overflow)
1239 #[cfg(target_word_size = "64")]
1240 checked_cast_impl!(CheckedMul, checked_mul, uint, u64, intrinsics::u64_mul_with_overflow)
1242 checked_impl!(CheckedMul, checked_mul, u8, intrinsics::u8_mul_with_overflow)
1243 checked_impl!(CheckedMul, checked_mul, u16, intrinsics::u16_mul_with_overflow)
1244 checked_impl!(CheckedMul, checked_mul, u32, intrinsics::u32_mul_with_overflow)
1245 checked_impl!(CheckedMul, checked_mul, u64, intrinsics::u64_mul_with_overflow)
1247 #[cfg(target_word_size = "32")]
1248 checked_cast_impl!(CheckedMul, checked_mul, int, i32, intrinsics::i32_mul_with_overflow)
1249 #[cfg(target_word_size = "64")]
1250 checked_cast_impl!(CheckedMul, checked_mul, int, i64, intrinsics::i64_mul_with_overflow)
1252 checked_impl!(CheckedMul, checked_mul, i8, intrinsics::i8_mul_with_overflow)
1253 checked_impl!(CheckedMul, checked_mul, i16, intrinsics::i16_mul_with_overflow)
1254 checked_impl!(CheckedMul, checked_mul, i32, intrinsics::i32_mul_with_overflow)
1255 checked_impl!(CheckedMul, checked_mul, i64, intrinsics::i64_mul_with_overflow)
1257 /// Performs division that returns `None` instead of wrapping around on underflow or overflow.
1258 pub trait CheckedDiv: Div<Self, Self> {
1259 /// Divides two numbers, checking for underflow or overflow. If underflow or overflow happens,
1260 /// `None` is returned.
1261 fn checked_div(&self, v: &Self) -> Option<Self>;
1264 macro_rules! checkeddiv_int_impl(
1265 ($t:ty, $min:expr) => {
1266 impl CheckedDiv for $t {
1268 fn checked_div(&self, v: &$t) -> Option<$t> {
1269 if *v == 0 || (*self == $min && *v == -1) {
1279 checkeddiv_int_impl!(int, int::MIN)
1280 checkeddiv_int_impl!(i8, i8::MIN)
1281 checkeddiv_int_impl!(i16, i16::MIN)
1282 checkeddiv_int_impl!(i32, i32::MIN)
1283 checkeddiv_int_impl!(i64, i64::MIN)
1285 macro_rules! checkeddiv_uint_impl(
1287 impl CheckedDiv for $t {
1289 fn checked_div(&self, v: &$t) -> Option<$t> {
1300 checkeddiv_uint_impl!(uint u8 u16 u32 u64)
1302 /// Helper function for testing numeric operations
1304 pub fn test_num<T:Num + NumCast + ::std::fmt::Show>(ten: T, two: T) {
1305 assert_eq!(ten.add(&two), cast(12).unwrap());
1306 assert_eq!(ten.sub(&two), cast(8).unwrap());
1307 assert_eq!(ten.mul(&two), cast(20).unwrap());
1308 assert_eq!(ten.div(&two), cast(5).unwrap());
1309 assert_eq!(ten.rem(&two), cast(0).unwrap());
1311 assert_eq!(ten.add(&two), ten + two);
1312 assert_eq!(ten.sub(&two), ten - two);
1313 assert_eq!(ten.mul(&two), ten * two);
1314 assert_eq!(ten.div(&two), ten / two);
1315 assert_eq!(ten.rem(&two), ten % two);
1318 /// Used for representing the classification of floating point numbers
1319 #[deriving(PartialEq, Show)]
1320 pub enum FPCategory {
1321 /// "Not a Number", often obtained by dividing by zero
1323 /// Positive or negative infinity
1325 /// Positive or negative zero
1327 /// De-normalized floating point representation (less precise than `FPNormal`)
1329 /// A regular floating point number
1333 /// Operations on primitive floating point numbers.
1334 // FIXME(#5527): In a future version of Rust, many of these functions will
1335 // become constants.
1337 // FIXME(#8888): Several of these functions have a parameter named
1338 // `unused_self`. Removing it requires #8888 to be fixed.
1339 pub trait Float: Signed + Primitive {
1340 /// Returns the NaN value.
1342 /// Returns the infinite value.
1343 fn infinity() -> Self;
1344 /// Returns the negative infinite value.
1345 fn neg_infinity() -> Self;
1347 fn neg_zero() -> Self;
1349 /// Returns true if this value is NaN and false otherwise.
1350 fn is_nan(self) -> bool;
1351 /// Returns true if this value is positive infinity or negative infinity and
1352 /// false otherwise.
1353 fn is_infinite(self) -> bool;
1354 /// Returns true if this number is neither infinite nor NaN.
1355 fn is_finite(self) -> bool;
1356 /// Returns true if this number is neither zero, infinite, denormal, or NaN.
1357 fn is_normal(self) -> bool;
1358 /// Returns the category that this number falls into.
1359 fn classify(self) -> FPCategory;
1361 // FIXME (#5527): These should be associated constants
1363 /// Returns the number of binary digits of mantissa that this type supports.
1364 fn mantissa_digits(unused_self: Option<Self>) -> uint;
1365 /// Returns the number of base-10 digits of precision that this type supports.
1366 fn digits(unused_self: Option<Self>) -> uint;
1367 /// Returns the difference between 1.0 and the smallest representable number larger than 1.0.
1368 fn epsilon() -> Self;
1369 /// Returns the minimum binary exponent that this type can represent.
1370 fn min_exp(unused_self: Option<Self>) -> int;
1371 /// Returns the maximum binary exponent that this type can represent.
1372 fn max_exp(unused_self: Option<Self>) -> int;
1373 /// Returns the minimum base-10 exponent that this type can represent.
1374 fn min_10_exp(unused_self: Option<Self>) -> int;
1375 /// Returns the maximum base-10 exponent that this type can represent.
1376 fn max_10_exp(unused_self: Option<Self>) -> int;
1377 /// Returns the smallest normalized positive number that this type can represent.
1378 fn min_pos_value(unused_self: Option<Self>) -> Self;
1380 /// Returns the mantissa, exponent and sign as integers, respectively.
1381 fn integer_decode(self) -> (u64, i16, i8);
1383 /// Return the largest integer less than or equal to a number.
1384 fn floor(self) -> Self;
1385 /// Return the smallest integer greater than or equal to a number.
1386 fn ceil(self) -> Self;
1387 /// Return the nearest integer to a number. Round half-way cases away from
1389 fn round(self) -> Self;
1390 /// Return the integer part of a number.
1391 fn trunc(self) -> Self;
1392 /// Return the fractional part of a number.
1393 fn fract(self) -> Self;
1395 /// Fused multiply-add. Computes `(self * a) + b` with only one rounding
1396 /// error. This produces a more accurate result with better performance than
1397 /// a separate multiplication operation followed by an add.
1398 fn mul_add(self, a: Self, b: Self) -> Self;
1399 /// Take the reciprocal (inverse) of a number, `1/x`.
1400 fn recip(self) -> Self;
1402 /// Raise a number to an integer power.
1404 /// Using this function is generally faster than using `powf`
1405 fn powi(self, n: i32) -> Self;
1406 /// Raise a number to a floating point power.
1407 fn powf(self, n: Self) -> Self;
1411 /// 1.0 / sqrt(2.0).
1412 fn frac_1_sqrt2() -> Self;
1414 /// Take the square root of a number.
1415 fn sqrt(self) -> Self;
1416 /// Take the reciprocal (inverse) square root of a number, `1/sqrt(x)`.
1417 fn rsqrt(self) -> Self;
1419 // FIXME (#5527): These should be associated constants
1421 /// Archimedes' constant.
1424 fn two_pi() -> Self;
1426 fn frac_pi_2() -> Self;
1428 fn frac_pi_3() -> Self;
1430 fn frac_pi_4() -> Self;
1432 fn frac_pi_6() -> Self;
1434 fn frac_pi_8() -> Self;
1436 fn frac_1_pi() -> Self;
1438 fn frac_2_pi() -> Self;
1440 fn frac_2_sqrtpi() -> Self;
1445 fn log2_e() -> Self;
1447 fn log10_e() -> Self;
1453 /// Returns `e^(self)`, (the exponential function).
1454 fn exp(self) -> Self;
1455 /// Returns 2 raised to the power of the number, `2^(self)`.
1456 fn exp2(self) -> Self;
1457 /// Returns the natural logarithm of the number.
1458 fn ln(self) -> Self;
1459 /// Returns the logarithm of the number with respect to an arbitrary base.
1460 fn log(self, base: Self) -> Self;
1461 /// Returns the base 2 logarithm of the number.
1462 fn log2(self) -> Self;
1463 /// Returns the base 10 logarithm of the number.
1464 fn log10(self) -> Self;
1466 /// Convert radians to degrees.
1467 fn to_degrees(self) -> Self;
1468 /// Convert degrees to radians.
1469 fn to_radians(self) -> Self;