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fuchsia / third_party / rust / e804a3cf256106c097d44f6e0212cd183122da07 / . / src / libcore / num / mod.rs
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// Copyright 2012-2014 The Rust Project Developers. See the COPYRIGHT
// file at the top-level directory of this distribution and at
// http://rust-lang.org/COPYRIGHT.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//! Numeric traits and functions for the built-in numeric types.
#![stable(feature = "rust1", since = "1.0.0")]
use char::CharExt;
use cmp::PartialOrd;
use convert::{From, TryFrom};
use fmt;
use intrinsics;
use marker::{Copy, Sized};
use mem::size_of;
use option::Option::{self, Some, None};
use result::Result::{self, Ok, Err};
use str::{FromStr, StrExt};
use slice::SliceExt;
/// Provides intentionally-wrapped arithmetic on `T`.
///
/// Operations like `+` on `u32` values is intended to never overflow,
/// and in some debug configurations overflow is detected and results
/// in a panic. While most arithmetic falls into this category, some
/// code explicitly expects and relies upon modular arithmetic (e.g.,
/// hashing).
///
/// Wrapping arithmetic can be achieved either through methods like
/// `wrapping_add`, or through the `Wrapping<T>` type, which says that
/// all standard arithmetic operations on the underlying value are
/// intended to have wrapping semantics.
///
/// # Examples
///
/// ```
/// use std::num::Wrapping;
///
/// let zero = Wrapping(0u32);
/// let one = Wrapping(1u32);
///
/// assert_eq!(std::u32::MAX, (zero - one).0);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default, Hash)]
pub struct Wrapping<T>(#[stable(feature = "rust1", since = "1.0.0")] pub T);
#[stable(feature = "rust1", since = "1.0.0")]
impl<T: fmt::Debug> fmt::Debug for Wrapping<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.0.fmt(f)
}
}
#[stable(feature = "wrapping_display", since = "1.10.0")]
impl<T: fmt::Display> fmt::Display for Wrapping<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.0.fmt(f)
}
}
#[stable(feature = "wrapping_fmt", since = "1.11.0")]
impl<T: fmt::Binary> fmt::Binary for Wrapping<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.0.fmt(f)
}
}
#[stable(feature = "wrapping_fmt", since = "1.11.0")]
impl<T: fmt::Octal> fmt::Octal for Wrapping<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.0.fmt(f)
}
}
#[stable(feature = "wrapping_fmt", since = "1.11.0")]
impl<T: fmt::LowerHex> fmt::LowerHex for Wrapping<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.0.fmt(f)
}
}
#[stable(feature = "wrapping_fmt", since = "1.11.0")]
impl<T: fmt::UpperHex> fmt::UpperHex for Wrapping<T> {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.0.fmt(f)
}
}
mod wrapping;
// All these modules are technically private and only exposed for libcoretest:
pub mod flt2dec;
pub mod dec2flt;
pub mod bignum;
pub mod diy_float;
/// Types that have a "zero" value.
///
/// This trait is intended for use in conjunction with `Add`, as an identity:
/// `x + T::zero() == x`.
#[unstable(feature = "zero_one",
reason = "unsure of placement, wants to use associated constants",
issue = "27739")]
#[rustc_deprecated(since = "1.11.0", reason = "no longer used for \
Iterator::sum")]
pub trait Zero: Sized {
/// The "zero" (usually, additive identity) for this type.
fn zero() -> Self;
}
/// Types that have a "one" value.
///
/// This trait is intended for use in conjunction with `Mul`, as an identity:
/// `x * T::one() == x`.
#[unstable(feature = "zero_one",
reason = "unsure of placement, wants to use associated constants",
issue = "27739")]
#[rustc_deprecated(since = "1.11.0", reason = "no longer used for \
Iterator::product")]
pub trait One: Sized {
/// The "one" (usually, multiplicative identity) for this type.
fn one() -> Self;
}
macro_rules! zero_one_impl {
($($t:ty)*) => ($(
#[unstable(feature = "zero_one",
reason = "unsure of placement, wants to use associated constants",
issue = "27739")]
#[allow(deprecated)]
impl Zero for $t {
#[inline]
fn zero() -> Self { 0 }
}
#[unstable(feature = "zero_one",
reason = "unsure of placement, wants to use associated constants",
issue = "27739")]
#[allow(deprecated)]
impl One for $t {
#[inline]
fn one() -> Self { 1 }
}
)*)
}
zero_one_impl! { u8 u16 u32 u64 usize i8 i16 i32 i64 isize }
macro_rules! zero_one_impl_float {
($($t:ty)*) => ($(
#[unstable(feature = "zero_one",
reason = "unsure of placement, wants to use associated constants",
issue = "27739")]
#[allow(deprecated)]
impl Zero for $t {
#[inline]
fn zero() -> Self { 0.0 }
}
#[unstable(feature = "zero_one",
reason = "unsure of placement, wants to use associated constants",
issue = "27739")]
#[allow(deprecated)]
impl One for $t {
#[inline]
fn one() -> Self { 1.0 }
}
)*)
}
zero_one_impl_float! { f32 f64 }
macro_rules! checked_op {
($U:ty, $op:path, $x:expr, $y:expr) => {{
let (result, overflowed) = unsafe { $op($x as $U, $y as $U) };
if overflowed { None } else { Some(result as Self) }
}}
}
// `Int` + `SignedInt` implemented for signed integers
macro_rules! int_impl {
($ActualT:ident, $UnsignedT:ty, $BITS:expr,
$add_with_overflow:path,
$sub_with_overflow:path,
$mul_with_overflow:path) => {
/// Returns the smallest value that can be represented by this integer type.
///
/// # Examples
///
/// ```
/// assert_eq!(i8::min_value(), -128);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub const fn min_value() -> Self {
(-1 as Self) << ($BITS - 1)
}
/// Returns the largest value that can be represented by this integer type.
///
/// # Examples
///
/// ```
/// assert_eq!(i8::max_value(), 127);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub const fn max_value() -> Self {
!Self::min_value()
}
/// Converts a string slice in a given base to an integer.
///
/// Leading and trailing whitespace represent an error.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(i32::from_str_radix("A", 16), Ok(10));
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> {
from_str_radix(src, radix)
}
/// Returns the number of ones in the binary representation of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = -0b1000_0000i8;
///
/// assert_eq!(n.count_ones(), 1);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn count_ones(self) -> u32 { (self as $UnsignedT).count_ones() }
/// Returns the number of zeros in the binary representation of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = -0b1000_0000i8;
///
/// assert_eq!(n.count_zeros(), 7);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn count_zeros(self) -> u32 {
(!self).count_ones()
}
/// Returns the number of leading zeros in the binary representation
/// of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = -1i16;
///
/// assert_eq!(n.leading_zeros(), 0);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn leading_zeros(self) -> u32 {
(self as $UnsignedT).leading_zeros()
}
/// Returns the number of trailing zeros in the binary representation
/// of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = -4i8;
///
/// assert_eq!(n.trailing_zeros(), 2);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn trailing_zeros(self) -> u32 {
(self as $UnsignedT).trailing_zeros()
}
/// Shifts the bits to the left by a specified amount, `n`,
/// wrapping the truncated bits to the end of the resulting integer.
///
/// Please note this isn't the same operation as `<<`!
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFi64;
/// let m = -0x76543210FEDCBA99i64;
///
/// assert_eq!(n.rotate_left(32), m);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn rotate_left(self, n: u32) -> Self {
(self as $UnsignedT).rotate_left(n) as Self
}
/// Shifts the bits to the right by a specified amount, `n`,
/// wrapping the truncated bits to the beginning of the resulting
/// integer.
///
/// Please note this isn't the same operation as `>>`!
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFi64;
/// let m = -0xFEDCBA987654322i64;
///
/// assert_eq!(n.rotate_right(4), m);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn rotate_right(self, n: u32) -> Self {
(self as $UnsignedT).rotate_right(n) as Self
}
/// Reverses the byte order of the integer.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFi64;
/// let m = -0x1032547698BADCFFi64;
///
/// assert_eq!(n.swap_bytes(), m);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn swap_bytes(self) -> Self {
(self as $UnsignedT).swap_bytes() as Self
}
/// Converts an integer from big endian to the target's endianness.
///
/// On big endian this is a no-op. On little endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFi64;
///
/// if cfg!(target_endian = "big") {
/// assert_eq!(i64::from_be(n), n)
/// } else {
/// assert_eq!(i64::from_be(n), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn from_be(x: Self) -> Self {
if cfg!(target_endian = "big") { x } else { x.swap_bytes() }
}
/// Converts an integer from little endian to the target's endianness.
///
/// On little endian this is a no-op. On big endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFi64;
///
/// if cfg!(target_endian = "little") {
/// assert_eq!(i64::from_le(n), n)
/// } else {
/// assert_eq!(i64::from_le(n), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn from_le(x: Self) -> Self {
if cfg!(target_endian = "little") { x } else { x.swap_bytes() }
}
/// Converts `self` to big endian from the target's endianness.
///
/// On big endian this is a no-op. On little endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFi64;
///
/// if cfg!(target_endian = "big") {
/// assert_eq!(n.to_be(), n)
/// } else {
/// assert_eq!(n.to_be(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn to_be(self) -> Self { // or not to be?
if cfg!(target_endian = "big") { self } else { self.swap_bytes() }
}
/// Converts `self` to little endian from the target's endianness.
///
/// On little endian this is a no-op. On big endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFi64;
///
/// if cfg!(target_endian = "little") {
/// assert_eq!(n.to_le(), n)
/// } else {
/// assert_eq!(n.to_le(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn to_le(self) -> Self {
if cfg!(target_endian = "little") { self } else { self.swap_bytes() }
}
/// Checked integer addition. Computes `self + other`, returning `None`
/// if overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(7i16.checked_add(32760), Some(32767));
/// assert_eq!(8i16.checked_add(32760), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn checked_add(self, other: Self) -> Option<Self> {
let (a, b) = self.overflowing_add(other);
if b {None} else {Some(a)}
}
/// Checked integer subtraction. Computes `self - other`, returning
/// `None` if underflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!((-127i8).checked_sub(1), Some(-128));
/// assert_eq!((-128i8).checked_sub(1), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn checked_sub(self, other: Self) -> Option<Self> {
let (a, b) = self.overflowing_sub(other);
if b {None} else {Some(a)}
}
/// Checked integer multiplication. Computes `self * other`, returning
/// `None` if underflow or overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(6i8.checked_mul(21), Some(126));
/// assert_eq!(6i8.checked_mul(22), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn checked_mul(self, other: Self) -> Option<Self> {
let (a, b) = self.overflowing_mul(other);
if b {None} else {Some(a)}
}
/// Checked integer division. Computes `self / other`, returning `None`
/// if `other == 0` or the operation results in underflow or overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!((-127i8).checked_div(-1), Some(127));
/// assert_eq!((-128i8).checked_div(-1), None);
/// assert_eq!((1i8).checked_div(0), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn checked_div(self, other: Self) -> Option<Self> {
if other == 0 {
None
} else {
let (a, b) = self.overflowing_div(other);
if b {None} else {Some(a)}
}
}
/// Checked integer remainder. Computes `self % other`, returning `None`
/// if `other == 0` or the operation results in underflow or overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use std::i32;
///
/// assert_eq!(5i32.checked_rem(2), Some(1));
/// assert_eq!(5i32.checked_rem(0), None);
/// assert_eq!(i32::MIN.checked_rem(-1), None);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn checked_rem(self, other: Self) -> Option<Self> {
if other == 0 {
None
} else {
let (a, b) = self.overflowing_rem(other);
if b {None} else {Some(a)}
}
}
/// Checked negation. Computes `-self`, returning `None` if `self ==
/// MIN`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use std::i32;
///
/// assert_eq!(5i32.checked_neg(), Some(-5));
/// assert_eq!(i32::MIN.checked_neg(), None);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn checked_neg(self) -> Option<Self> {
let (a, b) = self.overflowing_neg();
if b {None} else {Some(a)}
}
/// Checked shift left. Computes `self << rhs`, returning `None`
/// if `rhs` is larger than or equal to the number of bits in `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(0x10i32.checked_shl(4), Some(0x100));
/// assert_eq!(0x10i32.checked_shl(33), None);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn checked_shl(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shl(rhs);
if b {None} else {Some(a)}
}
/// Checked shift right. Computes `self >> rhs`, returning `None`
/// if `rhs` is larger than or equal to the number of bits in `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(0x10i32.checked_shr(4), Some(0x1));
/// assert_eq!(0x10i32.checked_shr(33), None);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn checked_shr(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shr(rhs);
if b {None} else {Some(a)}
}
/// Checked absolute value. Computes `self.abs()`, returning `None` if
/// `self == MIN`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// # #![feature(no_panic_abs)]
///
/// use std::i32;
///
/// assert_eq!((-5i32).checked_abs(), Some(5));
/// assert_eq!(i32::MIN.checked_abs(), None);
/// ```
#[unstable(feature = "no_panic_abs", issue = "35057")]
#[inline]
pub fn checked_abs(self) -> Option<Self> {
if self.is_negative() {
self.checked_neg()
} else {
Some(self)
}
}
/// Saturating integer addition. Computes `self + other`, saturating at
/// the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100i8.saturating_add(1), 101);
/// assert_eq!(100i8.saturating_add(127), 127);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn saturating_add(self, other: Self) -> Self {
match self.checked_add(other) {
Some(x) => x,
None if other >= 0 => Self::max_value(),
None => Self::min_value(),
}
}
/// Saturating integer subtraction. Computes `self - other`, saturating
/// at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100i8.saturating_sub(127), -27);
/// assert_eq!((-100i8).saturating_sub(127), -128);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn saturating_sub(self, other: Self) -> Self {
match self.checked_sub(other) {
Some(x) => x,
None if other >= 0 => Self::min_value(),
None => Self::max_value(),
}
}
/// Saturating integer multiplication. Computes `self * other`,
/// saturating at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use std::i32;
///
/// assert_eq!(100i32.saturating_mul(127), 12700);
/// assert_eq!((1i32 << 23).saturating_mul(1 << 23), i32::MAX);
/// assert_eq!((-1i32 << 23).saturating_mul(1 << 23), i32::MIN);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn saturating_mul(self, other: Self) -> Self {
self.checked_mul(other).unwrap_or_else(|| {
if (self < 0 && other < 0) || (self > 0 && other > 0) {
Self::max_value()
} else {
Self::min_value()
}
})
}
/// Wrapping (modular) addition. Computes `self + other`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100i8.wrapping_add(27), 127);
/// assert_eq!(100i8.wrapping_add(127), -29);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn wrapping_add(self, rhs: Self) -> Self {
unsafe {
intrinsics::overflowing_add(self, rhs)
}
}
/// Wrapping (modular) subtraction. Computes `self - other`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(0i8.wrapping_sub(127), -127);
/// assert_eq!((-2i8).wrapping_sub(127), 127);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn wrapping_sub(self, rhs: Self) -> Self {
unsafe {
intrinsics::overflowing_sub(self, rhs)
}
}
/// Wrapping (modular) multiplication. Computes `self *
/// other`, wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(10i8.wrapping_mul(12), 120);
/// assert_eq!(11i8.wrapping_mul(12), -124);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn wrapping_mul(self, rhs: Self) -> Self {
unsafe {
intrinsics::overflowing_mul(self, rhs)
}
}
/// Wrapping (modular) division. Computes `self / other`,
/// wrapping around at the boundary of the type.
///
/// The only case where such wrapping can occur is when one
/// divides `MIN / -1` on a signed type (where `MIN` is the
/// negative minimal value for the type); this is equivalent
/// to `-MIN`, a positive value that is too large to represent
/// in the type. In such a case, this function returns `MIN`
/// itself.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100u8.wrapping_div(10), 10);
/// assert_eq!((-128i8).wrapping_div(-1), -128);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_div(self, rhs: Self) -> Self {
self.overflowing_div(rhs).0
}
/// Wrapping (modular) remainder. Computes `self % other`,
/// wrapping around at the boundary of the type.
///
/// Such wrap-around never actually occurs mathematically;
/// implementation artifacts make `x % y` invalid for `MIN /
/// -1` on a signed type (where `MIN` is the negative
/// minimal value). In such a case, this function returns `0`.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100i8.wrapping_rem(10), 0);
/// assert_eq!((-128i8).wrapping_rem(-1), 0);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_rem(self, rhs: Self) -> Self {
self.overflowing_rem(rhs).0
}
/// Wrapping (modular) negation. Computes `-self`,
/// wrapping around at the boundary of the type.
///
/// The only case where such wrapping can occur is when one
/// negates `MIN` on a signed type (where `MIN` is the
/// negative minimal value for the type); this is a positive
/// value that is too large to represent in the type. In such
/// a case, this function returns `MIN` itself.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100i8.wrapping_neg(), -100);
/// assert_eq!((-128i8).wrapping_neg(), -128);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_neg(self) -> Self {
self.overflowing_neg().0
}
/// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
/// where `mask` removes any high-order bits of `rhs` that
/// would cause the shift to exceed the bitwidth of the type.
///
/// Note that this is *not* the same as a rotate-left; the
/// RHS of a wrapping shift-left is restricted to the range
/// of the type, rather than the bits shifted out of the LHS
/// being returned to the other end. The primitive integer
/// types all implement a `rotate_left` function, which may
/// be what you want instead.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!((-1i8).wrapping_shl(7), -128);
/// assert_eq!((-1i8).wrapping_shl(8), -1);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_shl(self, rhs: u32) -> Self {
self.overflowing_shl(rhs).0
}
/// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
/// where `mask` removes any high-order bits of `rhs` that
/// would cause the shift to exceed the bitwidth of the type.
///
/// Note that this is *not* the same as a rotate-right; the
/// RHS of a wrapping shift-right is restricted to the range
/// of the type, rather than the bits shifted out of the LHS
/// being returned to the other end. The primitive integer
/// types all implement a `rotate_right` function, which may
/// be what you want instead.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!((-128i8).wrapping_shr(7), -1);
/// assert_eq!((-128i8).wrapping_shr(8), -128);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_shr(self, rhs: u32) -> Self {
self.overflowing_shr(rhs).0
}
/// Wrapping (modular) absolute value. Computes `self.abs()`,
/// wrapping around at the boundary of the type.
///
/// The only case where such wrapping can occur is when one takes
/// the absolute value of the negative minimal value for the type
/// this is a positive value that is too large to represent in the
/// type. In such a case, this function returns `MIN` itself.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// # #![feature(no_panic_abs)]
///
/// assert_eq!(100i8.wrapping_abs(), 100);
/// assert_eq!((-100i8).wrapping_abs(), 100);
/// assert_eq!((-128i8).wrapping_abs(), -128);
/// assert_eq!((-128i8).wrapping_abs() as u8, 128);
/// ```
#[unstable(feature = "no_panic_abs", issue = "35057")]
#[inline(always)]
pub fn wrapping_abs(self) -> Self {
if self.is_negative() {
self.wrapping_neg()
} else {
self
}
}
/// Calculates `self` + `rhs`
///
/// Returns a tuple of the addition along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// use std::i32;
///
/// assert_eq!(5i32.overflowing_add(2), (7, false));
/// assert_eq!(i32::MAX.overflowing_add(1), (i32::MIN, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_add(self, rhs: Self) -> (Self, bool) {
unsafe {
let (a, b) = $add_with_overflow(self as $ActualT,
rhs as $ActualT);
(a as Self, b)
}
}
/// Calculates `self` - `rhs`
///
/// Returns a tuple of the subtraction along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// use std::i32;
///
/// assert_eq!(5i32.overflowing_sub(2), (3, false));
/// assert_eq!(i32::MIN.overflowing_sub(1), (i32::MAX, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
unsafe {
let (a, b) = $sub_with_overflow(self as $ActualT,
rhs as $ActualT);
(a as Self, b)
}
}
/// Calculates the multiplication of `self` and `rhs`.
///
/// Returns a tuple of the multiplication along with a boolean
/// indicating whether an arithmetic overflow would occur. If an
/// overflow would have occurred then the wrapped value is returned.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(5i32.overflowing_mul(2), (10, false));
/// assert_eq!(1_000_000_000i32.overflowing_mul(10), (1410065408, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
unsafe {
let (a, b) = $mul_with_overflow(self as $ActualT,
rhs as $ActualT);
(a as Self, b)
}
}
/// Calculates the divisor when `self` is divided by `rhs`.
///
/// Returns a tuple of the divisor along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// occur then self is returned.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// use std::i32;
///
/// assert_eq!(5i32.overflowing_div(2), (2, false));
/// assert_eq!(i32::MIN.overflowing_div(-1), (i32::MIN, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_div(self, rhs: Self) -> (Self, bool) {
if self == Self::min_value() && rhs == -1 {
(self, true)
} else {
(self / rhs, false)
}
}
/// Calculates the remainder when `self` is divided by `rhs`.
///
/// Returns a tuple of the remainder after dividing along with a boolean
/// indicating whether an arithmetic overflow would occur. If an
/// overflow would occur then 0 is returned.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// use std::i32;
///
/// assert_eq!(5i32.overflowing_rem(2), (1, false));
/// assert_eq!(i32::MIN.overflowing_rem(-1), (0, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
if self == Self::min_value() && rhs == -1 {
(0, true)
} else {
(self % rhs, false)
}
}
/// Negates self, overflowing if this is equal to the minimum value.
///
/// Returns a tuple of the negated version of self along with a boolean
/// indicating whether an overflow happened. If `self` is the minimum
/// value (e.g. `i32::MIN` for values of type `i32`), then the minimum
/// value will be returned again and `true` will be returned for an
/// overflow happening.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// use std::i32;
///
/// assert_eq!(2i32.overflowing_neg(), (-2, false));
/// assert_eq!(i32::MIN.overflowing_neg(), (i32::MIN, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_neg(self) -> (Self, bool) {
if self == Self::min_value() {
(Self::min_value(), true)
} else {
(-self, false)
}
}
/// Shifts self left by `rhs` bits.
///
/// Returns a tuple of the shifted version of self along with a boolean
/// indicating whether the shift value was larger than or equal to the
/// number of bits. If the shift value is too large, then value is
/// masked (N-1) where N is the number of bits, and this value is then
/// used to perform the shift.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(0x10i32.overflowing_shl(4), (0x100, false));
/// assert_eq!(0x10i32.overflowing_shl(36), (0x100, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
(self << (rhs & ($BITS - 1)), (rhs > ($BITS - 1)))
}
/// Shifts self right by `rhs` bits.
///
/// Returns a tuple of the shifted version of self along with a boolean
/// indicating whether the shift value was larger than or equal to the
/// number of bits. If the shift value is too large, then value is
/// masked (N-1) where N is the number of bits, and this value is then
/// used to perform the shift.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(0x10i32.overflowing_shr(4), (0x1, false));
/// assert_eq!(0x10i32.overflowing_shr(36), (0x1, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
(self >> (rhs & ($BITS - 1)), (rhs > ($BITS - 1)))
}
/// Computes the absolute value of `self`.
///
/// Returns a tuple of the absolute version of self along with a
/// boolean indicating whether an overflow happened. If self is the
/// minimum value (e.g. i32::MIN for values of type i32), then the
/// minimum value will be returned again and true will be returned for
/// an overflow happening.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// # #![feature(no_panic_abs)]
///
/// assert_eq!(10i8.overflowing_abs(), (10,false));
/// assert_eq!((-10i8).overflowing_abs(), (10,false));
/// assert_eq!((-128i8).overflowing_abs(), (-128,true));
/// ```
#[unstable(feature = "no_panic_abs", issue = "35057")]
#[inline]
pub fn overflowing_abs(self) -> (Self, bool) {
if self.is_negative() {
self.overflowing_neg()
} else {
(self, false)
}
}
/// Raises self to the power of `exp`, using exponentiation by squaring.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let x: i32 = 2; // or any other integer type
///
/// assert_eq!(x.pow(4), 16);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
#[rustc_inherit_overflow_checks]
pub fn pow(self, mut exp: u32) -> Self {
let mut base = self;
let mut acc = 1;
while exp > 1 {
if (exp & 1) == 1 {
acc = acc * base;
}
exp /= 2;
base = base * base;
}
// Deal with the final bit of the exponent separately, since
// squaring the base afterwards is not necessary and may cause a
// needless overflow.
if exp == 1 {
acc = acc * base;
}
acc
}
/// Computes the absolute value of `self`.
///
/// # Overflow behavior
///
/// The absolute value of `i32::min_value()` cannot be represented as an
/// `i32`, and attempting to calculate it will cause an overflow. This
/// means that code in debug mode will trigger a panic on this case and
/// optimized code will return `i32::min_value()` without a panic.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(10i8.abs(), 10);
/// assert_eq!((-10i8).abs(), 10);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
#[rustc_inherit_overflow_checks]
pub fn abs(self) -> Self {
if self.is_negative() {
// Note that the #[inline] above means that the overflow
// semantics of this negation depend on the crate we're being
// inlined into.
-self
} else {
self
}
}
/// Returns a number representing sign of `self`.
///
/// - `0` if the number is zero
/// - `1` if the number is positive
/// - `-1` if the number is negative
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(10i8.signum(), 1);
/// assert_eq!(0i8.signum(), 0);
/// assert_eq!((-10i8).signum(), -1);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn signum(self) -> Self {
match self {
n if n > 0 => 1,
0 => 0,
_ => -1,
}
}
/// Returns `true` if `self` is positive and `false` if the number
/// is zero or negative.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!(10i8.is_positive());
/// assert!(!(-10i8).is_positive());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_positive(self) -> bool { self > 0 }
/// Returns `true` if `self` is negative and `false` if the number
/// is zero or positive.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!((-10i8).is_negative());
/// assert!(!10i8.is_negative());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_negative(self) -> bool { self < 0 }
}
}
#[lang = "i8"]
impl i8 {
int_impl! { i8, u8, 8,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[lang = "i16"]
impl i16 {
int_impl! { i16, u16, 16,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[lang = "i32"]
impl i32 {
int_impl! { i32, u32, 32,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[lang = "i64"]
impl i64 {
int_impl! { i64, u64, 64,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[cfg(target_pointer_width = "16")]
#[lang = "isize"]
impl isize {
int_impl! { i16, u16, 16,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[cfg(target_pointer_width = "32")]
#[lang = "isize"]
impl isize {
int_impl! { i32, u32, 32,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[cfg(target_pointer_width = "64")]
#[lang = "isize"]
impl isize {
int_impl! { i64, u64, 64,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
// `Int` + `UnsignedInt` implemented for unsigned integers
macro_rules! uint_impl {
($ActualT:ty, $BITS:expr,
$ctpop:path,
$ctlz:path,
$cttz:path,
$bswap:path,
$add_with_overflow:path,
$sub_with_overflow:path,
$mul_with_overflow:path) => {
/// Returns the smallest value that can be represented by this integer type.
///
/// # Examples
///
/// ```
/// assert_eq!(u8::min_value(), 0);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub const fn min_value() -> Self { 0 }
/// Returns the largest value that can be represented by this integer type.
///
/// # Examples
///
/// ```
/// assert_eq!(u8::max_value(), 255);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub const fn max_value() -> Self { !0 }
/// Converts a string slice in a given base to an integer.
///
/// Leading and trailing whitespace represent an error.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(u32::from_str_radix("A", 16), Ok(10));
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn from_str_radix(src: &str, radix: u32) -> Result<Self, ParseIntError> {
from_str_radix(src, radix)
}
/// Returns the number of ones in the binary representation of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0b01001100u8;
///
/// assert_eq!(n.count_ones(), 3);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn count_ones(self) -> u32 {
unsafe { $ctpop(self as $ActualT) as u32 }
}
/// Returns the number of zeros in the binary representation of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0b01001100u8;
///
/// assert_eq!(n.count_zeros(), 5);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn count_zeros(self) -> u32 {
(!self).count_ones()
}
/// Returns the number of leading zeros in the binary representation
/// of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0b0101000u16;
///
/// assert_eq!(n.leading_zeros(), 10);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn leading_zeros(self) -> u32 {
unsafe { $ctlz(self as $ActualT) as u32 }
}
/// Returns the number of trailing zeros in the binary representation
/// of `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0b0101000u16;
///
/// assert_eq!(n.trailing_zeros(), 3);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn trailing_zeros(self) -> u32 {
// As of LLVM 3.6 the codegen for the zero-safe cttz8 intrinsic
// emits two conditional moves on x86_64. By promoting the value to
// u16 and setting bit 8, we get better code without any conditional
// operations.
// FIXME: There's a LLVM patch (http://reviews.llvm.org/D9284)
// pending, remove this workaround once LLVM generates better code
// for cttz8.
unsafe {
if $BITS == 8 {
intrinsics::cttz(self as u16 | 0x100) as u32
} else {
intrinsics::cttz(self) as u32
}
}
}
/// Shifts the bits to the left by a specified amount, `n`,
/// wrapping the truncated bits to the end of the resulting integer.
///
/// Please note this isn't the same operation as `<<`!
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFu64;
/// let m = 0x3456789ABCDEF012u64;
///
/// assert_eq!(n.rotate_left(12), m);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn rotate_left(self, n: u32) -> Self {
// Protect against undefined behaviour for over-long bit shifts
let n = n % $BITS;
(self << n) | (self >> (($BITS - n) % $BITS))
}
/// Shifts the bits to the right by a specified amount, `n`,
/// wrapping the truncated bits to the beginning of the resulting
/// integer.
///
/// Please note this isn't the same operation as `>>`!
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFu64;
/// let m = 0xDEF0123456789ABCu64;
///
/// assert_eq!(n.rotate_right(12), m);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn rotate_right(self, n: u32) -> Self {
// Protect against undefined behaviour for over-long bit shifts
let n = n % $BITS;
(self >> n) | (self << (($BITS - n) % $BITS))
}
/// Reverses the byte order of the integer.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFu64;
/// let m = 0xEFCDAB8967452301u64;
///
/// assert_eq!(n.swap_bytes(), m);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn swap_bytes(self) -> Self {
unsafe { $bswap(self as $ActualT) as Self }
}
/// Converts an integer from big endian to the target's endianness.
///
/// On big endian this is a no-op. On little endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFu64;
///
/// if cfg!(target_endian = "big") {
/// assert_eq!(u64::from_be(n), n)
/// } else {
/// assert_eq!(u64::from_be(n), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn from_be(x: Self) -> Self {
if cfg!(target_endian = "big") { x } else { x.swap_bytes() }
}
/// Converts an integer from little endian to the target's endianness.
///
/// On little endian this is a no-op. On big endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFu64;
///
/// if cfg!(target_endian = "little") {
/// assert_eq!(u64::from_le(n), n)
/// } else {
/// assert_eq!(u64::from_le(n), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn from_le(x: Self) -> Self {
if cfg!(target_endian = "little") { x } else { x.swap_bytes() }
}
/// Converts `self` to big endian from the target's endianness.
///
/// On big endian this is a no-op. On little endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFu64;
///
/// if cfg!(target_endian = "big") {
/// assert_eq!(n.to_be(), n)
/// } else {
/// assert_eq!(n.to_be(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn to_be(self) -> Self { // or not to be?
if cfg!(target_endian = "big") { self } else { self.swap_bytes() }
}
/// Converts `self` to little endian from the target's endianness.
///
/// On little endian this is a no-op. On big endian the bytes are
/// swapped.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// let n = 0x0123456789ABCDEFu64;
///
/// if cfg!(target_endian = "little") {
/// assert_eq!(n.to_le(), n)
/// } else {
/// assert_eq!(n.to_le(), n.swap_bytes())
/// }
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn to_le(self) -> Self {
if cfg!(target_endian = "little") { self } else { self.swap_bytes() }
}
/// Checked integer addition. Computes `self + other`, returning `None`
/// if overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(5u16.checked_add(65530), Some(65535));
/// assert_eq!(6u16.checked_add(65530), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn checked_add(self, other: Self) -> Option<Self> {
let (a, b) = self.overflowing_add(other);
if b {None} else {Some(a)}
}
/// Checked integer subtraction. Computes `self - other`, returning
/// `None` if underflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(1u8.checked_sub(1), Some(0));
/// assert_eq!(0u8.checked_sub(1), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn checked_sub(self, other: Self) -> Option<Self> {
let (a, b) = self.overflowing_sub(other);
if b {None} else {Some(a)}
}
/// Checked integer multiplication. Computes `self * other`, returning
/// `None` if underflow or overflow occurred.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(5u8.checked_mul(51), Some(255));
/// assert_eq!(5u8.checked_mul(52), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn checked_mul(self, other: Self) -> Option<Self> {
let (a, b) = self.overflowing_mul(other);
if b {None} else {Some(a)}
}
/// Checked integer division. Computes `self / other`, returning `None`
/// if `other == 0` or the operation results in underflow or overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(128u8.checked_div(2), Some(64));
/// assert_eq!(1u8.checked_div(0), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn checked_div(self, other: Self) -> Option<Self> {
match other {
0 => None,
other => Some(self / other),
}
}
/// Checked integer remainder. Computes `self % other`, returning `None`
/// if `other == 0` or the operation results in underflow or overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(5u32.checked_rem(2), Some(1));
/// assert_eq!(5u32.checked_rem(0), None);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn checked_rem(self, other: Self) -> Option<Self> {
if other == 0 {
None
} else {
Some(self % other)
}
}
/// Checked negation. Computes `-self`, returning `None` unless `self ==
/// 0`.
///
/// Note that negating any positive integer will overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(0u32.checked_neg(), Some(0));
/// assert_eq!(1u32.checked_neg(), None);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn checked_neg(self) -> Option<Self> {
let (a, b) = self.overflowing_neg();
if b {None} else {Some(a)}
}
/// Checked shift left. Computes `self << rhs`, returning `None`
/// if `rhs` is larger than or equal to the number of bits in `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(0x10u32.checked_shl(4), Some(0x100));
/// assert_eq!(0x10u32.checked_shl(33), None);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn checked_shl(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shl(rhs);
if b {None} else {Some(a)}
}
/// Checked shift right. Computes `self >> rhs`, returning `None`
/// if `rhs` is larger than or equal to the number of bits in `self`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(0x10u32.checked_shr(4), Some(0x1));
/// assert_eq!(0x10u32.checked_shr(33), None);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn checked_shr(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shr(rhs);
if b {None} else {Some(a)}
}
/// Saturating integer addition. Computes `self + other`, saturating at
/// the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100u8.saturating_add(1), 101);
/// assert_eq!(200u8.saturating_add(127), 255);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn saturating_add(self, other: Self) -> Self {
match self.checked_add(other) {
Some(x) => x,
None => Self::max_value(),
}
}
/// Saturating integer subtraction. Computes `self - other`, saturating
/// at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100u8.saturating_sub(27), 73);
/// assert_eq!(13u8.saturating_sub(127), 0);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn saturating_sub(self, other: Self) -> Self {
match self.checked_sub(other) {
Some(x) => x,
None => Self::min_value(),
}
}
/// Saturating integer multiplication. Computes `self * other`,
/// saturating at the numeric bounds instead of overflowing.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// use std::u32;
///
/// assert_eq!(100u32.saturating_mul(127), 12700);
/// assert_eq!((1u32 << 23).saturating_mul(1 << 23), u32::MAX);
/// ```
#[stable(feature = "wrapping", since = "1.7.0")]
#[inline]
pub fn saturating_mul(self, other: Self) -> Self {
self.checked_mul(other).unwrap_or(Self::max_value())
}
/// Wrapping (modular) addition. Computes `self + other`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(200u8.wrapping_add(55), 255);
/// assert_eq!(200u8.wrapping_add(155), 99);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn wrapping_add(self, rhs: Self) -> Self {
unsafe {
intrinsics::overflowing_add(self, rhs)
}
}
/// Wrapping (modular) subtraction. Computes `self - other`,
/// wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100u8.wrapping_sub(100), 0);
/// assert_eq!(100u8.wrapping_sub(155), 201);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn wrapping_sub(self, rhs: Self) -> Self {
unsafe {
intrinsics::overflowing_sub(self, rhs)
}
}
/// Wrapping (modular) multiplication. Computes `self *
/// other`, wrapping around at the boundary of the type.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(10u8.wrapping_mul(12), 120);
/// assert_eq!(25u8.wrapping_mul(12), 44);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn wrapping_mul(self, rhs: Self) -> Self {
unsafe {
intrinsics::overflowing_mul(self, rhs)
}
}
/// Wrapping (modular) division. Computes `self / other`.
/// Wrapped division on unsigned types is just normal division.
/// There's no way wrapping could ever happen.
/// This function exists, so that all operations
/// are accounted for in the wrapping operations.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100u8.wrapping_div(10), 10);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_div(self, rhs: Self) -> Self {
self / rhs
}
/// Wrapping (modular) remainder. Computes `self % other`.
/// Wrapped remainder calculation on unsigned types is
/// just the regular remainder calculation.
/// There's no way wrapping could ever happen.
/// This function exists, so that all operations
/// are accounted for in the wrapping operations.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100u8.wrapping_rem(10), 0);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_rem(self, rhs: Self) -> Self {
self % rhs
}
/// Wrapping (modular) negation. Computes `-self`,
/// wrapping around at the boundary of the type.
///
/// Since unsigned types do not have negative equivalents
/// all applications of this function will wrap (except for `-0`).
/// For values smaller than the corresponding signed type's maximum
/// the result is the same as casting the corresponding signed value.
/// Any larger values are equivalent to `MAX + 1 - (val - MAX - 1)` where
/// `MAX` is the corresponding signed type's maximum.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(100u8.wrapping_neg(), 156);
/// assert_eq!(0u8.wrapping_neg(), 0);
/// assert_eq!(180u8.wrapping_neg(), 76);
/// assert_eq!(180u8.wrapping_neg(), (127 + 1) - (180u8 - (127 + 1)));
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_neg(self) -> Self {
self.overflowing_neg().0
}
/// Panic-free bitwise shift-left; yields `self << mask(rhs)`,
/// where `mask` removes any high-order bits of `rhs` that
/// would cause the shift to exceed the bitwidth of the type.
///
/// Note that this is *not* the same as a rotate-left; the
/// RHS of a wrapping shift-left is restricted to the range
/// of the type, rather than the bits shifted out of the LHS
/// being returned to the other end. The primitive integer
/// types all implement a `rotate_left` function, which may
/// be what you want instead.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(1u8.wrapping_shl(7), 128);
/// assert_eq!(1u8.wrapping_shl(8), 1);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_shl(self, rhs: u32) -> Self {
self.overflowing_shl(rhs).0
}
/// Panic-free bitwise shift-right; yields `self >> mask(rhs)`,
/// where `mask` removes any high-order bits of `rhs` that
/// would cause the shift to exceed the bitwidth of the type.
///
/// Note that this is *not* the same as a rotate-right; the
/// RHS of a wrapping shift-right is restricted to the range
/// of the type, rather than the bits shifted out of the LHS
/// being returned to the other end. The primitive integer
/// types all implement a `rotate_right` function, which may
/// be what you want instead.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(128u8.wrapping_shr(7), 1);
/// assert_eq!(128u8.wrapping_shr(8), 128);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline(always)]
pub fn wrapping_shr(self, rhs: u32) -> Self {
self.overflowing_shr(rhs).0
}
/// Calculates `self` + `rhs`
///
/// Returns a tuple of the addition along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// use std::u32;
///
/// assert_eq!(5u32.overflowing_add(2), (7, false));
/// assert_eq!(u32::MAX.overflowing_add(1), (0, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_add(self, rhs: Self) -> (Self, bool) {
unsafe {
let (a, b) = $add_with_overflow(self as $ActualT,
rhs as $ActualT);
(a as Self, b)
}
}
/// Calculates `self` - `rhs`
///
/// Returns a tuple of the subtraction along with a boolean indicating
/// whether an arithmetic overflow would occur. If an overflow would
/// have occurred then the wrapped value is returned.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// use std::u32;
///
/// assert_eq!(5u32.overflowing_sub(2), (3, false));
/// assert_eq!(0u32.overflowing_sub(1), (u32::MAX, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_sub(self, rhs: Self) -> (Self, bool) {
unsafe {
let (a, b) = $sub_with_overflow(self as $ActualT,
rhs as $ActualT);
(a as Self, b)
}
}
/// Calculates the multiplication of `self` and `rhs`.
///
/// Returns a tuple of the multiplication along with a boolean
/// indicating whether an arithmetic overflow would occur. If an
/// overflow would have occurred then the wrapped value is returned.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(5u32.overflowing_mul(2), (10, false));
/// assert_eq!(1_000_000_000u32.overflowing_mul(10), (1410065408, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_mul(self, rhs: Self) -> (Self, bool) {
unsafe {
let (a, b) = $mul_with_overflow(self as $ActualT,
rhs as $ActualT);
(a as Self, b)
}
}
/// Calculates the divisor when `self` is divided by `rhs`.
///
/// Returns a tuple of the divisor along with a boolean indicating
/// whether an arithmetic overflow would occur. Note that for unsigned
/// integers overflow never occurs, so the second value is always
/// `false`.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(5u32.overflowing_div(2), (2, false));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_div(self, rhs: Self) -> (Self, bool) {
(self / rhs, false)
}
/// Calculates the remainder when `self` is divided by `rhs`.
///
/// Returns a tuple of the remainder after dividing along with a boolean
/// indicating whether an arithmetic overflow would occur. Note that for
/// unsigned integers overflow never occurs, so the second value is
/// always `false`.
///
/// # Panics
///
/// This function will panic if `rhs` is 0.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(5u32.overflowing_rem(2), (1, false));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
(self % rhs, false)
}
/// Negates self in an overflowing fashion.
///
/// Returns `!self + 1` using wrapping operations to return the value
/// that represents the negation of this unsigned value. Note that for
/// positive unsigned values overflow always occurs, but negating 0 does
/// not overflow.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(0u32.overflowing_neg(), (0, false));
/// assert_eq!(2u32.overflowing_neg(), (-2i32 as u32, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_neg(self) -> (Self, bool) {
((!self).wrapping_add(1), self != 0)
}
/// Shifts self left by `rhs` bits.
///
/// Returns a tuple of the shifted version of self along with a boolean
/// indicating whether the shift value was larger than or equal to the
/// number of bits. If the shift value is too large, then value is
/// masked (N-1) where N is the number of bits, and this value is then
/// used to perform the shift.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(0x10u32.overflowing_shl(4), (0x100, false));
/// assert_eq!(0x10u32.overflowing_shl(36), (0x100, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_shl(self, rhs: u32) -> (Self, bool) {
(self << (rhs & ($BITS - 1)), (rhs > ($BITS - 1)))
}
/// Shifts self right by `rhs` bits.
///
/// Returns a tuple of the shifted version of self along with a boolean
/// indicating whether the shift value was larger than or equal to the
/// number of bits. If the shift value is too large, then value is
/// masked (N-1) where N is the number of bits, and this value is then
/// used to perform the shift.
///
/// # Examples
///
/// Basic usage
///
/// ```
/// assert_eq!(0x10u32.overflowing_shr(4), (0x1, false));
/// assert_eq!(0x10u32.overflowing_shr(36), (0x1, true));
/// ```
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_shr(self, rhs: u32) -> (Self, bool) {
(self >> (rhs & ($BITS - 1)), (rhs > ($BITS - 1)))
}
/// Raises self to the power of `exp`, using exponentiation by squaring.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(2u32.pow(4), 16);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
#[rustc_inherit_overflow_checks]
pub fn pow(self, mut exp: u32) -> Self {
let mut base = self;
let mut acc = 1;
let mut prev_base = self;
let mut base_oflo = false;
while exp > 0 {
if (exp & 1) == 1 {
if base_oflo {
// ensure overflow occurs in the same manner it
// would have otherwise (i.e. signal any exception
// it would have otherwise).
acc = acc * (prev_base * prev_base);
} else {
acc = acc * base;
}
}
prev_base = base;
let (new_base, new_base_oflo) = base.overflowing_mul(base);
base = new_base;
base_oflo = new_base_oflo;
exp /= 2;
}
acc
}
/// Returns `true` if and only if `self == 2^k` for some `k`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert!(16u8.is_power_of_two());
/// assert!(!10u8.is_power_of_two());
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn is_power_of_two(self) -> bool {
(self.wrapping_sub(1)) & self == 0 && !(self == 0)
}
/// Returns the smallest power of two greater than or equal to `self`.
/// Unspecified behavior on overflow.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(2u8.next_power_of_two(), 2);
/// assert_eq!(3u8.next_power_of_two(), 4);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[inline]
pub fn next_power_of_two(self) -> Self {
let bits = size_of::<Self>() * 8;
let one: Self = 1;
one << ((bits - self.wrapping_sub(one).leading_zeros() as usize) % bits)
}
/// Returns the smallest power of two greater than or equal to `n`. If
/// the next power of two is greater than the type's maximum value,
/// `None` is returned, otherwise the power of two is wrapped in `Some`.
///
/// # Examples
///
/// Basic usage:
///
/// ```
/// assert_eq!(2u8.checked_next_power_of_two(), Some(2));
/// assert_eq!(3u8.checked_next_power_of_two(), Some(4));
/// assert_eq!(200u8.checked_next_power_of_two(), None);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
pub fn checked_next_power_of_two(self) -> Option<Self> {
let npot = self.next_power_of_two();
if npot >= self {
Some(npot)
} else {
None
}
}
}
}
#[lang = "u8"]
impl u8 {
uint_impl! { u8, 8,
intrinsics::ctpop,
intrinsics::ctlz,
intrinsics::cttz,
intrinsics::bswap,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[lang = "u16"]
impl u16 {
uint_impl! { u16, 16,
intrinsics::ctpop,
intrinsics::ctlz,
intrinsics::cttz,
intrinsics::bswap,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[lang = "u32"]
impl u32 {
uint_impl! { u32, 32,
intrinsics::ctpop,
intrinsics::ctlz,
intrinsics::cttz,
intrinsics::bswap,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[lang = "u64"]
impl u64 {
uint_impl! { u64, 64,
intrinsics::ctpop,
intrinsics::ctlz,
intrinsics::cttz,
intrinsics::bswap,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[cfg(target_pointer_width = "16")]
#[lang = "usize"]
impl usize {
uint_impl! { u16, 16,
intrinsics::ctpop,
intrinsics::ctlz,
intrinsics::cttz,
intrinsics::bswap,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[cfg(target_pointer_width = "32")]
#[lang = "usize"]
impl usize {
uint_impl! { u32, 32,
intrinsics::ctpop,
intrinsics::ctlz,
intrinsics::cttz,
intrinsics::bswap,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
#[cfg(target_pointer_width = "64")]
#[lang = "usize"]
impl usize {
uint_impl! { u64, 64,
intrinsics::ctpop,
intrinsics::ctlz,
intrinsics::cttz,
intrinsics::bswap,
intrinsics::add_with_overflow,
intrinsics::sub_with_overflow,
intrinsics::mul_with_overflow }
}
/// A classification of floating point numbers.
///
/// This `enum` is used as the return type for [`f32::classify()`] and [`f64::classify()`]. See
/// their documentation for more.
///
/// [`f32::classify()`]: ../../std/primitive.f32.html#method.classify
/// [`f64::classify()`]: ../../std/primitive.f64.html#method.classify
///
/// # Examples
///
/// ```
/// use std::num::FpCategory;
/// use std::f32;
///
/// let num = 12.4_f32;
/// let inf = f32::INFINITY;
/// let zero = 0f32;
/// let sub: f32 = 1.1754942e-38;
/// let nan = f32::NAN;
///
/// assert_eq!(num.classify(), FpCategory::Normal);
/// assert_eq!(inf.classify(), FpCategory::Infinite);
/// assert_eq!(zero.classify(), FpCategory::Zero);
/// assert_eq!(nan.classify(), FpCategory::Nan);
/// assert_eq!(sub.classify(), FpCategory::Subnormal);
/// ```
#[derive(Copy, Clone, PartialEq, Debug)]
#[stable(feature = "rust1", since = "1.0.0")]
pub enum FpCategory {
/// "Not a Number", often obtained by dividing by zero.
#[stable(feature = "rust1", since = "1.0.0")]
Nan,
/// Positive or negative infinity.
#[stable(feature = "rust1", since = "1.0.0")]
Infinite ,
/// Positive or negative zero.
#[stable(feature = "rust1", since = "1.0.0")]
Zero,
/// De-normalized floating point representation (less precise than `Normal`).
#[stable(feature = "rust1", since = "1.0.0")]
Subnormal,
/// A regular floating point number.
#[stable(feature = "rust1", since = "1.0.0")]
Normal,
}
/// A built-in floating point number.
#[doc(hidden)]
#[unstable(feature = "core_float",
reason = "stable interface is via `impl f{32,64}` in later crates",
issue = "32110")]
pub trait Float: Sized {
/// Returns the NaN value.
#[unstable(feature = "float_extras", reason = "needs removal",
issue = "27752")]
#[rustc_deprecated(since = "1.11.0",
reason = "never really came to fruition and easily \
implementable outside the standard library")]
fn nan() -> Self;
/// Returns the infinite value.
#[unstable(feature = "float_extras", reason = "needs removal",
issue = "27752")]
#[rustc_deprecated(since = "1.11.0",
reason = "never really came to fruition and easily \
implementable outside the standard library")]
fn infinity() -> Self;
/// Returns the negative infinite value.
#[unstable(feature = "float_extras", reason = "needs removal",
issue = "27752")]
#[rustc_deprecated(since = "1.11.0",
reason = "never really came to fruition and easily \
implementable outside the standard library")]
fn neg_infinity() -> Self;
/// Returns -0.0.
#[unstable(feature = "float_extras", reason = "needs removal",
issue = "27752")]
#[rustc_deprecated(since = "1.11.0",
reason = "never really came to fruition and easily \
implementable outside the standard library")]
fn neg_zero() -> Self;
/// Returns 0.0.
#[unstable(feature = "float_extras", reason = "needs removal",
issue = "27752")]
#[rustc_deprecated(since = "1.11.0",
reason = "never really came to fruition and easily \
implementable outside the standard library")]
fn zero() -> Self;
/// Returns 1.0.
#[unstable(feature = "float_extras", reason = "needs removal",
issue = "27752")]
#[rustc_deprecated(since = "1.11.0",
reason = "never really came to fruition and easily \
implementable outside the standard library")]
fn one() -> Self;
/// Returns true if this value is NaN and false otherwise.
#[stable(feature = "core", since = "1.6.0")]
fn is_nan(self) -> bool;
/// Returns true if this value is positive infinity or negative infinity and
/// false otherwise.
#[stable(feature = "core", since = "1.6.0")]
fn is_infinite(self) -> bool;
/// Returns true if this number is neither infinite nor NaN.
#[stable(feature = "core", since = "1.6.0")]
fn is_finite(self) -> bool;
/// Returns true if this number is neither zero, infinite, denormal, or NaN.
#[stable(feature = "core", since = "1.6.0")]
fn is_normal(self) -> bool;
/// Returns the category that this number falls into.
#[stable(feature = "core", since = "1.6.0")]
fn classify(self) -> FpCategory;
/// Returns the mantissa, exponent and sign as integers, respectively.
#[unstable(feature = "float_extras", reason = "signature is undecided",
issue = "27752")]
#[rustc_deprecated(since = "1.11.0",
reason = "never really came to fruition and easily \
implementable outside the standard library")]
fn integer_decode(self) -> (u64, i16, i8);
/// Computes the absolute value of `self`. Returns `Float::nan()` if the
/// number is `Float::nan()`.
#[stable(feature = "core", since = "1.6.0")]
fn abs(self) -> Self;
/// Returns a number that represents the sign of `self`.
///
/// - `1.0` if the number is positive, `+0.0` or `Float::infinity()`
/// - `-1.0` if the number is negative, `-0.0` or `Float::neg_infinity()`
/// - `Float::nan()` if the number is `Float::nan()`
#[stable(feature = "core", since = "1.6.0")]
fn signum(self) -> Self;
/// Returns `true` if `self` is positive, including `+0.0` and
/// `Float::infinity()`.
#[stable(feature = "core", since = "1.6.0")]
fn is_sign_positive(self) -> bool;
/// Returns `true` if `self` is negative, including `-0.0` and
/// `Float::neg_infinity()`.
#[stable(feature = "core", since = "1.6.0")]
fn is_sign_negative(self) -> bool;
/// Take the reciprocal (inverse) of a number, `1/x`.
#[stable(feature = "core", since = "1.6.0")]
fn recip(self) -> Self;
/// Raise a number to an integer power.
///
/// Using this function is generally faster than using `powf`
#[stable(feature = "core", since = "1.6.0")]
fn powi(self, n: i32) -> Self;
/// Convert radians to degrees.
#[stable(feature = "deg_rad_conversions", since="1.7.0")]
fn to_degrees(self) -> Self;
/// Convert degrees to radians.
#[stable(feature = "deg_rad_conversions", since="1.7.0")]
fn to_radians(self) -> Self;
}
macro_rules! from_str_radix_int_impl {
($($t:ty)*) => {$(
#[stable(feature = "rust1", since = "1.0.0")]
impl FromStr for $t {
type Err = ParseIntError;
fn from_str(src: &str) -> Result<Self, ParseIntError> {
from_str_radix(src, 10)
}
}
)*}
}
from_str_radix_int_impl! { isize i8 i16 i32 i64 usize u8 u16 u32 u64 }
/// The error type returned when a checked integral type conversion fails.
#[unstable(feature = "try_from", issue = "33417")]
#[derive(Debug, Copy, Clone)]
pub struct TryFromIntError(());
impl TryFromIntError {
#[unstable(feature = "int_error_internals",
reason = "available through Error trait and this method should \
not be exposed publicly",
issue = "0")]
#[doc(hidden)]
pub fn __description(&self) -> &str {
"out of range integral type conversion attempted"
}
}
#[unstable(feature = "try_from", issue = "33417")]
impl fmt::Display for TryFromIntError {
fn fmt(&self, fmt: &mut fmt::Formatter) -> fmt::Result {
self.__description().fmt(fmt)
}
}
macro_rules! same_sign_from_int_impl {
($storage:ty, $target:ty, $($source:ty),*) => {$(
#[stable(feature = "rust1", since = "1.0.0")]
impl TryFrom<$source> for $target {
type Err = TryFromIntError;
fn try_from(u: $source) -> Result<$target, TryFromIntError> {
let min = <$target as FromStrRadixHelper>::min_value() as $storage;
let max = <$target as FromStrRadixHelper>::max_value() as $storage;
if u as $storage < min || u as $storage > max {
Err(TryFromIntError(()))
} else {
Ok(u as $target)
}
}
}
)*}
}
same_sign_from_int_impl!(u64, u8, u8, u16, u32, u64, usize);
same_sign_from_int_impl!(i64, i8, i8, i16, i32, i64, isize);
same_sign_from_int_impl!(u64, u16, u8, u16, u32, u64, usize);
same_sign_from_int_impl!(i64, i16, i8, i16, i32, i64, isize);
same_sign_from_int_impl!(u64, u32, u8, u16, u32, u64, usize);
same_sign_from_int_impl!(i64, i32, i8, i16, i32, i64, isize);
same_sign_from_int_impl!(u64, u64, u8, u16, u32, u64, usize);
same_sign_from_int_impl!(i64, i64, i8, i16, i32, i64, isize);
same_sign_from_int_impl!(u64, usize, u8, u16, u32, u64, usize);
same_sign_from_int_impl!(i64, isize, i8, i16, i32, i64, isize);
macro_rules! cross_sign_from_int_impl {
($unsigned:ty, $($signed:ty),*) => {$(
#[stable(feature = "rust1", since = "1.0.0")]
impl TryFrom<$unsigned> for $signed {
type Err = TryFromIntError;
fn try_from(u: $unsigned) -> Result<$signed, TryFromIntError> {
let max = <$signed as FromStrRadixHelper>::max_value() as u64;
if u as u64 > max {
Err(TryFromIntError(()))
} else {
Ok(u as $signed)
}
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl TryFrom<$signed> for $unsigned {
type Err = TryFromIntError;
fn try_from(u: $signed) -> Result<$unsigned, TryFromIntError> {
let max = <$unsigned as FromStrRadixHelper>::max_value() as u64;
if u < 0 || u as u64 > max {
Err(TryFromIntError(()))
} else {
Ok(u as $unsigned)
}
}
}
)*}
}
cross_sign_from_int_impl!(u8, i8, i16, i32, i64, isize);
cross_sign_from_int_impl!(u16, i8, i16, i32, i64, isize);
cross_sign_from_int_impl!(u32, i8, i16, i32, i64, isize);
cross_sign_from_int_impl!(u64, i8, i16, i32, i64, isize);
cross_sign_from_int_impl!(usize, i8, i16, i32, i64, isize);
#[doc(hidden)]
trait FromStrRadixHelper: PartialOrd + Copy {
fn min_value() -> Self;
fn max_value() -> Self;
fn from_u32(u: u32) -> Self;
fn checked_mul(&self, other: u32) -> Option<Self>;
fn checked_sub(&self, other: u32) -> Option<Self>;
fn checked_add(&self, other: u32) -> Option<Self>;
}
macro_rules! doit {
($($t:ty)*) => ($(impl FromStrRadixHelper for $t {
fn min_value() -> Self { Self::min_value() }
fn max_value() -> Self { Self::max_value() }
fn from_u32(u: u32) -> Self { u as Self }
fn checked_mul(&self, other: u32) -> Option<Self> {
Self::checked_mul(*self, other as Self)
}
fn checked_sub(&self, other: u32) -> Option<Self> {
Self::checked_sub(*self, other as Self)
}
fn checked_add(&self, other: u32) -> Option<Self> {
Self::checked_add(*self, other as Self)
}
})*)
}
doit! { i8 i16 i32 i64 isize u8 u16 u32 u64 usize }
fn from_str_radix<T: FromStrRadixHelper>(src: &str, radix: u32)
-> Result<T, ParseIntError> {
use self::IntErrorKind::*;
use self::ParseIntError as PIE;
assert!(radix >= 2 && radix <= 36,
"from_str_radix_int: must lie in the range `[2, 36]` - found {}",
radix);
if src.is_empty() {
return Err(PIE { kind: Empty });
}
let is_signed_ty = T::from_u32(0) > T::min_value();
// all valid digits are ascii, so we will just iterate over the utf8 bytes
// and cast them to chars. .to_digit() will safely return None for anything
// other than a valid ascii digit for the given radix, including the first-byte
// of multi-byte sequences
let src = src.as_bytes();
let (is_positive, digits) = match src[0] {
b'+' => (true, &src[1..]),
b'-' if is_signed_ty => (false, &src[1..]),
_ => (true, src)
};
if digits.is_empty() {
return Err(PIE { kind: Empty });
}
let mut result = T::from_u32(0);
if is_positive {
// The number is positive
for &c in digits {
let x = match (c as char).to_digit(radix) {
Some(x) => x,
None => return Err(PIE { kind: InvalidDigit }),
};
result = match result.checked_mul(radix) {
Some(result) => result,
None => return Err(PIE { kind: Overflow }),
};
result = match result.checked_add(x) {
Some(result) => result,
None => return Err(PIE { kind: Overflow }),
};
}
} else {
// The number is negative
for &c in digits {
let x = match (c as char).to_digit(radix) {
Some(x) => x,
None => return Err(PIE { kind: InvalidDigit }),
};
result = match result.checked_mul(radix) {
Some(result) => result,
None => return Err(PIE { kind: Underflow }),
};
result = match result.checked_sub(x) {
Some(result) => result,
None => return Err(PIE { kind: Underflow }),
};
}
}
Ok(result)
}
/// An error which can be returned when parsing an integer.
///
/// This error is used as the error type for the `from_str_radix()` functions
/// on the primitive integer types, such as [`i8::from_str_radix()`].
///
/// [`i8::from_str_radix()`]: ../../std/primitive.i8.html#method.from_str_radix
#[derive(Debug, Clone, PartialEq)]
#[stable(feature = "rust1", since = "1.0.0")]
pub struct ParseIntError { kind: IntErrorKind }
#[derive(Debug, Clone, PartialEq)]
enum IntErrorKind {
Empty,
InvalidDigit,
Overflow,
Underflow,
}
impl ParseIntError {
#[unstable(feature = "int_error_internals",
reason = "available through Error trait and this method should \
not be exposed publicly",
issue = "0")]
#[doc(hidden)]
pub fn __description(&self) -> &str {
match self.kind {
IntErrorKind::Empty => "cannot parse integer from empty string",
IntErrorKind::InvalidDigit => "invalid digit found in string",
IntErrorKind::Overflow => "number too large to fit in target type",
IntErrorKind::Underflow => "number too small to fit in target type",
}
}
}
#[stable(feature = "rust1", since = "1.0.0")]
impl fmt::Display for ParseIntError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
self.__description().fmt(f)
}
}
#[stable(feature = "rust1", since = "1.0.0")]
pub use num::dec2flt::ParseFloatError;
// Conversion traits for primitive integer and float types
// Conversions T -> T are covered by a blanket impl and therefore excluded
// Some conversions from and to usize/isize are not implemented due to portability concerns
macro_rules! impl_from {
($Small: ty, $Large: ty) => {
#[stable(feature = "lossless_prim_conv", since = "1.5.0")]
impl From<$Small> for $Large {
#[inline]
fn from(small: $Small) -> $Large {
small as $Large
}
}
}
}
// Unsigned -> Unsigned
impl_from! { u8, u16 }
impl_from! { u8, u32 }
impl_from! { u8, u64 }
impl_from! { u8, usize }
impl_from! { u16, u32 }
impl_from! { u16, u64 }
impl_from! { u32, u64 }
// Signed -> Signed
impl_from! { i8, i16 }
impl_from! { i8, i32 }
impl_from! { i8, i64 }
impl_from! { i8, isize }
impl_from! { i16, i32 }
impl_from! { i16, i64 }
impl_from! { i32, i64 }
// Unsigned -> Signed
impl_from! { u8, i16 }
impl_from! { u8, i32 }
impl_from! { u8, i64 }
impl_from! { u16, i32 }
impl_from! { u16, i64 }
impl_from! { u32, i64 }
// Note: integers can only be represented with full precision in a float if
// they fit in the significand, which is 24 bits in f32 and 53 bits in f64.
// Lossy float conversions are not implemented at this time.
// Signed -> Float
impl_from! { i8, f32 }
impl_from! { i8, f64 }
impl_from! { i16, f32 }
impl_from! { i16, f64 }
impl_from! { i32, f64 }
// Unsigned -> Float
impl_from! { u8, f32 }
impl_from! { u8, f64 }
impl_from! { u16, f32 }
impl_from! { u16, f64 }
impl_from! { u32, f64 }
// Float -> Float
impl_from! { f32, f64 }