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Diffstat (limited to 'library/core/src/num/saturating.rs')
| -rw-r--r-- | library/core/src/num/saturating.rs | 1081 |
1 files changed, 1081 insertions, 0 deletions
diff --git a/library/core/src/num/saturating.rs b/library/core/src/num/saturating.rs new file mode 100644 index 000000000..8982473b2 --- /dev/null +++ b/library/core/src/num/saturating.rs @@ -0,0 +1,1081 @@ +//! Definitions of `Saturating<T>`. + +use crate::fmt; +use crate::ops::{Add, AddAssign, BitAnd, BitAndAssign, BitOr, BitOrAssign}; +use crate::ops::{BitXor, BitXorAssign, Div, DivAssign}; +use crate::ops::{Mul, MulAssign, Neg, Not, Rem, RemAssign}; +use crate::ops::{Shl, ShlAssign, Shr, ShrAssign, Sub, SubAssign}; + +/// Provides intentionally-saturating arithmetic on `T`. +/// +/// Operations like `+` on `u32` values are 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 saturating arithmetic. +/// +/// Saturating arithmetic can be achieved either through methods like +/// `saturating_add`, or through the `Saturating<T>` type, which says that +/// all standard arithmetic operations on the underlying value are +/// intended to have saturating semantics. +/// +/// The underlying value can be retrieved through the `.0` index of the +/// `Saturating` tuple. +/// +/// # Examples +/// +/// ``` +/// #![feature(saturating_int_impl)] +/// use std::num::Saturating; +/// +/// let max = Saturating(u32::MAX); +/// let one = Saturating(1u32); +/// +/// assert_eq!(u32::MAX, (max + one).0); +/// ``` +#[unstable(feature = "saturating_int_impl", issue = "87920")] +#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default, Hash)] +#[repr(transparent)] +pub struct Saturating<T>(#[unstable(feature = "saturating_int_impl", issue = "87920")] pub T); + +#[unstable(feature = "saturating_int_impl", issue = "87920")] +impl<T: fmt::Debug> fmt::Debug for Saturating<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[unstable(feature = "saturating_int_impl", issue = "87920")] +impl<T: fmt::Display> fmt::Display for Saturating<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[unstable(feature = "saturating_int_impl", issue = "87920")] +impl<T: fmt::Binary> fmt::Binary for Saturating<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[unstable(feature = "saturating_int_impl", issue = "87920")] +impl<T: fmt::Octal> fmt::Octal for Saturating<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[unstable(feature = "saturating_int_impl", issue = "87920")] +impl<T: fmt::LowerHex> fmt::LowerHex for Saturating<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} + +#[unstable(feature = "saturating_int_impl", issue = "87920")] +impl<T: fmt::UpperHex> fmt::UpperHex for Saturating<T> { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + self.0.fmt(f) + } +} +#[allow(unused_macros)] +macro_rules! sh_impl_signed { + ($t:ident, $f:ident) => { + // FIXME what is the correct implementation here? see discussion https://github.com/rust-lang/rust/pull/87921#discussion_r695870065 + // + // #[unstable(feature = "saturating_int_impl", issue = "87920")] + // impl Shl<$f> for Saturating<$t> { + // type Output = Saturating<$t>; + // + // #[inline] + // fn shl(self, other: $f) -> Saturating<$t> { + // if other < 0 { + // Saturating(self.0.shr((-other & self::shift_max::$t as $f) as u32)) + // } else { + // Saturating(self.0.shl((other & self::shift_max::$t as $f) as u32)) + // } + // } + // } + // forward_ref_binop! { impl Shl, shl for Saturating<$t>, $f, + // #[unstable(feature = "saturating_int_impl", issue = "87920")] } + // + // #[unstable(feature = "saturating_int_impl", issue = "87920")] + // impl ShlAssign<$f> for Saturating<$t> { + // #[inline] + // fn shl_assign(&mut self, other: $f) { + // *self = *self << other; + // } + // } + // forward_ref_op_assign! { impl ShlAssign, shl_assign for Saturating<$t>, $f } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Shr<$f> for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn shr(self, other: $f) -> Saturating<$t> { + if other < 0 { + Saturating(self.0.shl((-other & self::shift_max::$t as $f) as u32)) + } else { + Saturating(self.0.shr((other & self::shift_max::$t as $f) as u32)) + } + } + } + forward_ref_binop! { impl Shr, shr for Saturating<$t>, $f, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl ShrAssign<$f> for Saturating<$t> { + #[inline] + fn shr_assign(&mut self, other: $f) { + *self = *self >> other; + } + } + forward_ref_op_assign! { impl ShrAssign, shr_assign for Saturating<$t>, $f } + }; +} + +macro_rules! sh_impl_unsigned { + ($t:ident, $f:ident) => { + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Shl<$f> for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn shl(self, other: $f) -> Saturating<$t> { + Saturating(self.0.wrapping_shl(other as u32)) + } + } + forward_ref_binop! { impl Shl, shl for Saturating<$t>, $f, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl ShlAssign<$f> for Saturating<$t> { + #[inline] + fn shl_assign(&mut self, other: $f) { + *self = *self << other; + } + } + forward_ref_op_assign! { impl ShlAssign, shl_assign for Saturating<$t>, $f } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Shr<$f> for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn shr(self, other: $f) -> Saturating<$t> { + Saturating(self.0.wrapping_shr(other as u32)) + } + } + forward_ref_binop! { impl Shr, shr for Saturating<$t>, $f, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl ShrAssign<$f> for Saturating<$t> { + #[inline] + fn shr_assign(&mut self, other: $f) { + *self = *self >> other; + } + } + forward_ref_op_assign! { impl ShrAssign, shr_assign for Saturating<$t>, $f } + }; +} + +// FIXME (#23545): uncomment the remaining impls +macro_rules! sh_impl_all { + ($($t:ident)*) => ($( + //sh_impl_unsigned! { $t, u8 } + //sh_impl_unsigned! { $t, u16 } + //sh_impl_unsigned! { $t, u32 } + //sh_impl_unsigned! { $t, u64 } + //sh_impl_unsigned! { $t, u128 } + sh_impl_unsigned! { $t, usize } + + //sh_impl_signed! { $t, i8 } + //sh_impl_signed! { $t, i16 } + //sh_impl_signed! { $t, i32 } + //sh_impl_signed! { $t, i64 } + //sh_impl_signed! { $t, i128 } + //sh_impl_signed! { $t, isize } + )*) +} + +sh_impl_all! { u8 u16 u32 u64 u128 usize i8 i16 i32 i64 i128 isize } + +// FIXME(30524): impl Op<T> for Saturating<T>, impl OpAssign<T> for Saturating<T> +macro_rules! saturating_impl { + ($($t:ty)*) => ($( + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Add for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn add(self, other: Saturating<$t>) -> Saturating<$t> { + Saturating(self.0.saturating_add(other.0)) + } + } + forward_ref_binop! { impl Add, add for Saturating<$t>, Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl AddAssign for Saturating<$t> { + #[inline] + fn add_assign(&mut self, other: Saturating<$t>) { + *self = *self + other; + } + } + forward_ref_op_assign! { impl AddAssign, add_assign for Saturating<$t>, Saturating<$t> } + + #[unstable(feature = "saturating_int_assign_impl", issue = "92354")] + impl AddAssign<$t> for Saturating<$t> { + #[inline] + fn add_assign(&mut self, other: $t) { + *self = *self + Saturating(other); + } + } + forward_ref_op_assign! { impl AddAssign, add_assign for Saturating<$t>, $t } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Sub for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn sub(self, other: Saturating<$t>) -> Saturating<$t> { + Saturating(self.0.saturating_sub(other.0)) + } + } + forward_ref_binop! { impl Sub, sub for Saturating<$t>, Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl SubAssign for Saturating<$t> { + #[inline] + fn sub_assign(&mut self, other: Saturating<$t>) { + *self = *self - other; + } + } + forward_ref_op_assign! { impl SubAssign, sub_assign for Saturating<$t>, Saturating<$t> } + + #[unstable(feature = "saturating_int_assign_impl", issue = "92354")] + impl SubAssign<$t> for Saturating<$t> { + #[inline] + fn sub_assign(&mut self, other: $t) { + *self = *self - Saturating(other); + } + } + forward_ref_op_assign! { impl SubAssign, sub_assign for Saturating<$t>, $t } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Mul for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn mul(self, other: Saturating<$t>) -> Saturating<$t> { + Saturating(self.0.saturating_mul(other.0)) + } + } + forward_ref_binop! { impl Mul, mul for Saturating<$t>, Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl MulAssign for Saturating<$t> { + #[inline] + fn mul_assign(&mut self, other: Saturating<$t>) { + *self = *self * other; + } + } + forward_ref_op_assign! { impl MulAssign, mul_assign for Saturating<$t>, Saturating<$t> } + + #[unstable(feature = "saturating_int_assign_impl", issue = "92354")] + impl MulAssign<$t> for Saturating<$t> { + #[inline] + fn mul_assign(&mut self, other: $t) { + *self = *self * Saturating(other); + } + } + forward_ref_op_assign! { impl MulAssign, mul_assign for Saturating<$t>, $t } + + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert_eq!(Saturating(2", stringify!($t), "), Saturating(5", stringify!($t), ") / Saturating(2));")] + #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MAX), Saturating(", stringify!($t), "::MAX) / Saturating(1));")] + #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MIN), Saturating(", stringify!($t), "::MIN) / Saturating(1));")] + /// ``` + /// + /// ```should_panic + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let _ = Saturating(0", stringify!($t), ") / Saturating(0);")] + /// ``` + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Div for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn div(self, other: Saturating<$t>) -> Saturating<$t> { + Saturating(self.0.saturating_div(other.0)) + } + } + forward_ref_binop! { impl Div, div for Saturating<$t>, Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl DivAssign for Saturating<$t> { + #[inline] + fn div_assign(&mut self, other: Saturating<$t>) { + *self = *self / other; + } + } + forward_ref_op_assign! { impl DivAssign, div_assign for Saturating<$t>, Saturating<$t> } + + #[unstable(feature = "saturating_int_assign_impl", issue = "92354")] + impl DivAssign<$t> for Saturating<$t> { + #[inline] + fn div_assign(&mut self, other: $t) { + *self = *self / Saturating(other); + } + } + forward_ref_op_assign! { impl DivAssign, div_assign for Saturating<$t>, $t } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Rem for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn rem(self, other: Saturating<$t>) -> Saturating<$t> { + Saturating(self.0.rem(other.0)) + } + } + forward_ref_binop! { impl Rem, rem for Saturating<$t>, Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl RemAssign for Saturating<$t> { + #[inline] + fn rem_assign(&mut self, other: Saturating<$t>) { + *self = *self % other; + } + } + forward_ref_op_assign! { impl RemAssign, rem_assign for Saturating<$t>, Saturating<$t> } + + #[unstable(feature = "saturating_int_assign_impl", issue = "92354")] + impl RemAssign<$t> for Saturating<$t> { + #[inline] + fn rem_assign(&mut self, other: $t) { + *self = *self % Saturating(other); + } + } + forward_ref_op_assign! { impl RemAssign, rem_assign for Saturating<$t>, $t } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Not for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn not(self) -> Saturating<$t> { + Saturating(!self.0) + } + } + forward_ref_unop! { impl Not, not for Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl BitXor for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn bitxor(self, other: Saturating<$t>) -> Saturating<$t> { + Saturating(self.0 ^ other.0) + } + } + forward_ref_binop! { impl BitXor, bitxor for Saturating<$t>, Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl BitXorAssign for Saturating<$t> { + #[inline] + fn bitxor_assign(&mut self, other: Saturating<$t>) { + *self = *self ^ other; + } + } + forward_ref_op_assign! { impl BitXorAssign, bitxor_assign for Saturating<$t>, Saturating<$t> } + + #[unstable(feature = "saturating_int_assign_impl", issue = "92354")] + impl BitXorAssign<$t> for Saturating<$t> { + #[inline] + fn bitxor_assign(&mut self, other: $t) { + *self = *self ^ Saturating(other); + } + } + forward_ref_op_assign! { impl BitXorAssign, bitxor_assign for Saturating<$t>, $t } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl BitOr for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn bitor(self, other: Saturating<$t>) -> Saturating<$t> { + Saturating(self.0 | other.0) + } + } + forward_ref_binop! { impl BitOr, bitor for Saturating<$t>, Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl BitOrAssign for Saturating<$t> { + #[inline] + fn bitor_assign(&mut self, other: Saturating<$t>) { + *self = *self | other; + } + } + forward_ref_op_assign! { impl BitOrAssign, bitor_assign for Saturating<$t>, Saturating<$t> } + + #[unstable(feature = "saturating_int_assign_impl", issue = "92354")] + impl BitOrAssign<$t> for Saturating<$t> { + #[inline] + fn bitor_assign(&mut self, other: $t) { + *self = *self | Saturating(other); + } + } + forward_ref_op_assign! { impl BitOrAssign, bitor_assign for Saturating<$t>, $t } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl BitAnd for Saturating<$t> { + type Output = Saturating<$t>; + + #[inline] + fn bitand(self, other: Saturating<$t>) -> Saturating<$t> { + Saturating(self.0 & other.0) + } + } + forward_ref_binop! { impl BitAnd, bitand for Saturating<$t>, Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl BitAndAssign for Saturating<$t> { + #[inline] + fn bitand_assign(&mut self, other: Saturating<$t>) { + *self = *self & other; + } + } + forward_ref_op_assign! { impl BitAndAssign, bitand_assign for Saturating<$t>, Saturating<$t> } + + #[unstable(feature = "saturating_int_assign_impl", issue = "92354")] + impl BitAndAssign<$t> for Saturating<$t> { + #[inline] + fn bitand_assign(&mut self, other: $t) { + *self = *self & Saturating(other); + } + } + forward_ref_op_assign! { impl BitAndAssign, bitand_assign for Saturating<$t>, $t } + + )*) +} + +saturating_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } + +macro_rules! saturating_int_impl { + ($($t:ty)*) => ($( + impl Saturating<$t> { + /// Returns the smallest value that can be represented by this integer type. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert_eq!(<Saturating<", stringify!($t), ">>::MIN, Saturating(", stringify!($t), "::MIN));")] + /// ``` + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const MIN: Self = Self(<$t>::MIN); + + /// Returns the largest value that can be represented by this integer type. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert_eq!(<Saturating<", stringify!($t), ">>::MAX, Saturating(", stringify!($t), "::MAX));")] + /// ``` + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const MAX: Self = Self(<$t>::MAX); + + /// Returns the size of this integer type in bits. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert_eq!(<Saturating<", stringify!($t), ">>::BITS, ", stringify!($t), "::BITS);")] + /// ``` + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const BITS: u32 = <$t>::BITS; + + /// Returns the number of ones in the binary representation of `self`. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let n = Saturating(0b01001100", stringify!($t), ");")] + /// + /// assert_eq!(n.count_ones(), 3); + /// ``` + #[inline] + #[doc(alias = "popcount")] + #[doc(alias = "popcnt")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn count_ones(self) -> u32 { + self.0.count_ones() + } + + /// Returns the number of zeros in the binary representation of `self`. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert_eq!(Saturating(!0", stringify!($t), ").count_zeros(), 0);")] + /// ``` + #[inline] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn count_zeros(self) -> u32 { + self.0.count_zeros() + } + + /// Returns the number of trailing zeros in the binary representation of `self`. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let n = Saturating(0b0101000", stringify!($t), ");")] + /// + /// assert_eq!(n.trailing_zeros(), 3); + /// ``` + #[inline] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn trailing_zeros(self) -> u32 { + self.0.trailing_zeros() + } + + /// Shifts the bits to the left by a specified amount, `n`, + /// saturating the truncated bits to the end of the resulting + /// integer. + /// + /// Please note this isn't the same operation as the `<<` shifting + /// operator! + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + /// let n: Saturating<i64> = Saturating(0x0123456789ABCDEF); + /// let m: Saturating<i64> = Saturating(-0x76543210FEDCBA99); + /// + /// assert_eq!(n.rotate_left(32), m); + /// ``` + #[inline] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn rotate_left(self, n: u32) -> Self { + Saturating(self.0.rotate_left(n)) + } + + /// Shifts the bits to the right by a specified amount, `n`, + /// saturating the truncated bits to the beginning of the resulting + /// integer. + /// + /// Please note this isn't the same operation as the `>>` shifting + /// operator! + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + /// let n: Saturating<i64> = Saturating(0x0123456789ABCDEF); + /// let m: Saturating<i64> = Saturating(-0xFEDCBA987654322); + /// + /// assert_eq!(n.rotate_right(4), m); + /// ``` + #[inline] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn rotate_right(self, n: u32) -> Self { + Saturating(self.0.rotate_right(n)) + } + + /// Reverses the byte order of the integer. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + /// let n: Saturating<i16> = Saturating(0b0000000_01010101); + /// assert_eq!(n, Saturating(85)); + /// + /// let m = n.swap_bytes(); + /// + /// assert_eq!(m, Saturating(0b01010101_00000000)); + /// assert_eq!(m, Saturating(21760)); + /// ``` + #[inline] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn swap_bytes(self) -> Self { + Saturating(self.0.swap_bytes()) + } + + /// Reverses the bit pattern of the integer. + /// + /// # Examples + /// + /// Please note that this example is shared between integer types. + /// Which explains why `i16` is used here. + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + /// let n = Saturating(0b0000000_01010101i16); + /// assert_eq!(n, Saturating(85)); + /// + /// let m = n.reverse_bits(); + /// + /// assert_eq!(m.0 as u16, 0b10101010_00000000); + /// assert_eq!(m, Saturating(-22016)); + /// ``` + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + #[rustc_const_unstable(feature = "saturating_int_impl", issue = "87920")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn reverse_bits(self) -> Self { + Saturating(self.0.reverse_bits()) + } + + /// 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: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let n = Saturating(0x1A", stringify!($t), ");")] + /// + /// if cfg!(target_endian = "big") { + #[doc = concat!(" assert_eq!(<Saturating<", stringify!($t), ">>::from_be(n), n)")] + /// } else { + #[doc = concat!(" assert_eq!(<Saturating<", stringify!($t), ">>::from_be(n), n.swap_bytes())")] + /// } + /// ``` + #[inline] + #[must_use] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn from_be(x: Self) -> Self { + Saturating(<$t>::from_be(x.0)) + } + + /// Converts an integer from little endian to the target's endianness. + /// + /// On little endian this is a no-op. On big endian the bytes are + /// swapped. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let n = Saturating(0x1A", stringify!($t), ");")] + /// + /// if cfg!(target_endian = "little") { + #[doc = concat!(" assert_eq!(<Saturating<", stringify!($t), ">>::from_le(n), n)")] + /// } else { + #[doc = concat!(" assert_eq!(<Saturating<", stringify!($t), ">>::from_le(n), n.swap_bytes())")] + /// } + /// ``` + #[inline] + #[must_use] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn from_le(x: Self) -> Self { + Saturating(<$t>::from_le(x.0)) + } + + /// Converts `self` to big endian from the target's endianness. + /// + /// On big endian this is a no-op. On little endian the bytes are + /// swapped. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let n = Saturating(0x1A", stringify!($t), ");")] + /// + /// if cfg!(target_endian = "big") { + /// assert_eq!(n.to_be(), n) + /// } else { + /// assert_eq!(n.to_be(), n.swap_bytes()) + /// } + /// ``` + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn to_be(self) -> Self { + Saturating(self.0.to_be()) + } + + /// 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: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let n = Saturating(0x1A", stringify!($t), ");")] + /// + /// if cfg!(target_endian = "little") { + /// assert_eq!(n.to_le(), n) + /// } else { + /// assert_eq!(n.to_le(), n.swap_bytes()) + /// } + /// ``` + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn to_le(self) -> Self { + Saturating(self.0.to_le()) + } + + /// Raises self to the power of `exp`, using exponentiation by squaring. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert_eq!(Saturating(3", stringify!($t), ").pow(4), Saturating(81));")] + /// ``` + /// + /// Results that are too large are saturated: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + /// assert_eq!(Saturating(3i8).pow(5), Saturating(127)); + /// assert_eq!(Saturating(3i8).pow(6), Saturating(127)); + /// ``` + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub fn pow(self, exp: u32) -> Self { + Saturating(self.0.saturating_pow(exp)) + } + } + )*) +} + +saturating_int_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 } + +macro_rules! saturating_int_impl_signed { + ($($t:ty)*) => ($( + impl Saturating<$t> { + /// Returns the number of leading zeros in the binary representation of `self`. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let n = Saturating(", stringify!($t), "::MAX >> 2);")] + /// + /// assert_eq!(n.leading_zeros(), 3); + /// ``` + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn leading_zeros(self) -> u32 { + self.0.leading_zeros() + } + + /// Saturating absolute value. Computes `self.abs()`, returning `MAX` if `self == MIN` + /// instead of overflowing. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert_eq!(Saturating(100", stringify!($t), ").abs(), Saturating(100));")] + #[doc = concat!("assert_eq!(Saturating(-100", stringify!($t), ").abs(), Saturating(100));")] + #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MIN).abs(), Saturating((", stringify!($t), "::MIN + 1).abs()));")] + #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MIN).abs(), Saturating(", stringify!($t), "::MIN.saturating_abs()));")] + #[doc = concat!("assert_eq!(Saturating(", stringify!($t), "::MIN).abs(), Saturating(", stringify!($t), "::MAX));")] + /// ``` + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub fn abs(self) -> Saturating<$t> { + Saturating(self.0.saturating_abs()) + } + + /// 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: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert_eq!(Saturating(10", stringify!($t), ").signum(), Saturating(1));")] + #[doc = concat!("assert_eq!(Saturating(0", stringify!($t), ").signum(), Saturating(0));")] + #[doc = concat!("assert_eq!(Saturating(-10", stringify!($t), ").signum(), Saturating(-1));")] + /// ``` + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub fn signum(self) -> Saturating<$t> { + Saturating(self.0.signum()) + } + + /// Returns `true` if `self` is positive and `false` if the number is zero or + /// negative. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert!(Saturating(10", stringify!($t), ").is_positive());")] + #[doc = concat!("assert!(!Saturating(-10", stringify!($t), ").is_positive());")] + /// ``` + #[must_use] + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn is_positive(self) -> bool { + self.0.is_positive() + } + + /// Returns `true` if `self` is negative and `false` if the number is zero or + /// positive. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert!(Saturating(-10", stringify!($t), ").is_negative());")] + #[doc = concat!("assert!(!Saturating(10", stringify!($t), ").is_negative());")] + /// ``` + #[must_use] + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub const fn is_negative(self) -> bool { + self.0.is_negative() + } + } + + #[unstable(feature = "saturating_int_impl", issue = "87920")] + impl Neg for Saturating<$t> { + type Output = Self; + #[inline] + fn neg(self) -> Self { + Saturating(self.0.saturating_neg()) + } + } + forward_ref_unop! { impl Neg, neg for Saturating<$t>, + #[unstable(feature = "saturating_int_impl", issue = "87920")] } + )*) +} + +saturating_int_impl_signed! { isize i8 i16 i32 i64 i128 } + +macro_rules! saturating_int_impl_unsigned { + ($($t:ty)*) => ($( + impl Saturating<$t> { + /// Returns the number of leading zeros in the binary representation of `self`. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("let n = Saturating(", stringify!($t), "::MAX >> 2);")] + /// + /// assert_eq!(n.leading_zeros(), 2); + /// ``` + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + #[must_use = "this returns the result of the operation, \ + without modifying the original"] + pub const fn leading_zeros(self) -> u32 { + self.0.leading_zeros() + } + + /// Returns `true` if and only if `self == 2^k` for some `k`. + /// + /// # Examples + /// + /// Basic usage: + /// + /// ``` + /// #![feature(saturating_int_impl)] + /// use std::num::Saturating; + /// + #[doc = concat!("assert!(Saturating(16", stringify!($t), ").is_power_of_two());")] + #[doc = concat!("assert!(!Saturating(10", stringify!($t), ").is_power_of_two());")] + /// ``` + #[must_use] + #[inline] + #[unstable(feature = "saturating_int_impl", issue = "87920")] + pub fn is_power_of_two(self) -> bool { + self.0.is_power_of_two() + } + + } + )*) +} + +saturating_int_impl_unsigned! { usize u8 u16 u32 u64 u128 } + +// Related to potential Shl and ShlAssign implementation +// +// mod shift_max { +// #![allow(non_upper_case_globals)] +// +// #[cfg(target_pointer_width = "16")] +// mod platform { +// pub const usize: u32 = super::u16; +// pub const isize: u32 = super::i16; +// } +// +// #[cfg(target_pointer_width = "32")] +// mod platform { +// pub const usize: u32 = super::u32; +// pub const isize: u32 = super::i32; +// } +// +// #[cfg(target_pointer_width = "64")] +// mod platform { +// pub const usize: u32 = super::u64; +// pub const isize: u32 = super::i64; +// } +// +// pub const i8: u32 = (1 << 3) - 1; +// pub const i16: u32 = (1 << 4) - 1; +// pub const i32: u32 = (1 << 5) - 1; +// pub const i64: u32 = (1 << 6) - 1; +// pub const i128: u32 = (1 << 7) - 1; +// pub use self::platform::isize; +// +// pub const u8: u32 = i8; +// pub const u16: u32 = i16; +// pub const u32: u32 = i32; +// pub const u64: u32 = i64; +// pub const u128: u32 = i128; +// pub use self::platform::usize; +// } |