[rustc.git] / library / core / src / num / wrapping.rs

//! Definitions of `Wrapping<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-wrapped 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 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.
///
/// The underlying value can be retrieved through the `.0` index of the
/// `Wrapping` tuple.
///
/// # Examples
///
/// ```
/// use std::num::Wrapping;
///
/// let zero = Wrapping(0u32);
/// let one = Wrapping(1u32);
///
/// assert_eq!(u32::MAX, (zero - one).0);
/// ```
#[stable(feature = "rust1", since = "1.0.0")]
#[derive(PartialEq, Eq, PartialOrd, Ord, Clone, Copy, Default, Hash)]
#[repr(transparent)]
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)
    }
}

#[allow(unused_macros)]
macro_rules! sh_impl_signed {
    ($t:ident, $f:ident) => {
        #[stable(feature = "rust1", since = "1.0.0")]
        impl Shl<$f> for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn shl(self, other: $f) -> Wrapping<$t> {
                if other < 0 {
                    Wrapping(self.0.wrapping_shr((-other & self::shift_max::$t as $f) as u32))
                } else {
                    Wrapping(self.0.wrapping_shl((other & self::shift_max::$t as $f) as u32))
                }
            }
        }
        forward_ref_binop! { impl Shl, shl for Wrapping<$t>, $f,
        #[stable(feature = "wrapping_ref_ops", since = "1.39.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl ShlAssign<$f> for Wrapping<$t> {
            #[inline]
            fn shl_assign(&mut self, other: $f) {
                *self = *self << other;
            }
        }
        forward_ref_op_assign! { impl ShlAssign, shl_assign for Wrapping<$t>, $f }

        #[stable(feature = "rust1", since = "1.0.0")]
        impl Shr<$f> for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn shr(self, other: $f) -> Wrapping<$t> {
                if other < 0 {
                    Wrapping(self.0.wrapping_shl((-other & self::shift_max::$t as $f) as u32))
                } else {
                    Wrapping(self.0.wrapping_shr((other & self::shift_max::$t as $f) as u32))
                }
            }
        }
        forward_ref_binop! { impl Shr, shr for Wrapping<$t>, $f,
        #[stable(feature = "wrapping_ref_ops", since = "1.39.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl ShrAssign<$f> for Wrapping<$t> {
            #[inline]
            fn shr_assign(&mut self, other: $f) {
                *self = *self >> other;
            }
        }
        forward_ref_op_assign! { impl ShrAssign, shr_assign for Wrapping<$t>, $f }
    };
}

macro_rules! sh_impl_unsigned {
    ($t:ident, $f:ident) => {
        #[stable(feature = "rust1", since = "1.0.0")]
        impl Shl<$f> for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn shl(self, other: $f) -> Wrapping<$t> {
                Wrapping(self.0.wrapping_shl((other & self::shift_max::$t as $f) as u32))
            }
        }
        forward_ref_binop! { impl Shl, shl for Wrapping<$t>, $f,
        #[stable(feature = "wrapping_ref_ops", since = "1.39.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl ShlAssign<$f> for Wrapping<$t> {
            #[inline]
            fn shl_assign(&mut self, other: $f) {
                *self = *self << other;
            }
        }
        forward_ref_op_assign! { impl ShlAssign, shl_assign for Wrapping<$t>, $f }

        #[stable(feature = "rust1", since = "1.0.0")]
        impl Shr<$f> for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn shr(self, other: $f) -> Wrapping<$t> {
                Wrapping(self.0.wrapping_shr((other & self::shift_max::$t as $f) as u32))
            }
        }
        forward_ref_binop! { impl Shr, shr for Wrapping<$t>, $f,
        #[stable(feature = "wrapping_ref_ops", since = "1.39.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl ShrAssign<$f> for Wrapping<$t> {
            #[inline]
            fn shr_assign(&mut self, other: $f) {
                *self = *self >> other;
            }
        }
        forward_ref_op_assign! { impl ShrAssign, shr_assign for Wrapping<$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 Wrapping<T>, impl OpAssign<T> for Wrapping<T>
macro_rules! wrapping_impl {
    ($($t:ty)*) => ($(
        #[stable(feature = "rust1", since = "1.0.0")]
        impl Add for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn add(self, other: Wrapping<$t>) -> Wrapping<$t> {
                Wrapping(self.0.wrapping_add(other.0))
            }
        }
        forward_ref_binop! { impl Add, add for Wrapping<$t>, Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl AddAssign for Wrapping<$t> {
            #[inline]
            fn add_assign(&mut self, other: Wrapping<$t>) {
                *self = *self + other;
            }
        }
        forward_ref_op_assign! { impl AddAssign, add_assign for Wrapping<$t>, Wrapping<$t> }

        #[stable(feature = "rust1", since = "1.0.0")]
        impl Sub for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn sub(self, other: Wrapping<$t>) -> Wrapping<$t> {
                Wrapping(self.0.wrapping_sub(other.0))
            }
        }
        forward_ref_binop! { impl Sub, sub for Wrapping<$t>, Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl SubAssign for Wrapping<$t> {
            #[inline]
            fn sub_assign(&mut self, other: Wrapping<$t>) {
                *self = *self - other;
            }
        }
        forward_ref_op_assign! { impl SubAssign, sub_assign for Wrapping<$t>, Wrapping<$t> }

        #[stable(feature = "rust1", since = "1.0.0")]
        impl Mul for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn mul(self, other: Wrapping<$t>) -> Wrapping<$t> {
                Wrapping(self.0.wrapping_mul(other.0))
            }
        }
        forward_ref_binop! { impl Mul, mul for Wrapping<$t>, Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl MulAssign for Wrapping<$t> {
            #[inline]
            fn mul_assign(&mut self, other: Wrapping<$t>) {
                *self = *self * other;
            }
        }
        forward_ref_op_assign! { impl MulAssign, mul_assign for Wrapping<$t>, Wrapping<$t> }

        #[stable(feature = "wrapping_div", since = "1.3.0")]
        impl Div for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn div(self, other: Wrapping<$t>) -> Wrapping<$t> {
                Wrapping(self.0.wrapping_div(other.0))
            }
        }
        forward_ref_binop! { impl Div, div for Wrapping<$t>, Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl DivAssign for Wrapping<$t> {
            #[inline]
            fn div_assign(&mut self, other: Wrapping<$t>) {
                *self = *self / other;
            }
        }
        forward_ref_op_assign! { impl DivAssign, div_assign for Wrapping<$t>, Wrapping<$t> }

        #[stable(feature = "wrapping_impls", since = "1.7.0")]
        impl Rem for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn rem(self, other: Wrapping<$t>) -> Wrapping<$t> {
                Wrapping(self.0.wrapping_rem(other.0))
            }
        }
        forward_ref_binop! { impl Rem, rem for Wrapping<$t>, Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl RemAssign for Wrapping<$t> {
            #[inline]
            fn rem_assign(&mut self, other: Wrapping<$t>) {
                *self = *self % other;
            }
        }
        forward_ref_op_assign! { impl RemAssign, rem_assign for Wrapping<$t>, Wrapping<$t> }

        #[stable(feature = "rust1", since = "1.0.0")]
        impl Not for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn not(self) -> Wrapping<$t> {
                Wrapping(!self.0)
            }
        }
        forward_ref_unop! { impl Not, not for Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "rust1", since = "1.0.0")]
        impl BitXor for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn bitxor(self, other: Wrapping<$t>) -> Wrapping<$t> {
                Wrapping(self.0 ^ other.0)
            }
        }
        forward_ref_binop! { impl BitXor, bitxor for Wrapping<$t>, Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl BitXorAssign for Wrapping<$t> {
            #[inline]
            fn bitxor_assign(&mut self, other: Wrapping<$t>) {
                *self = *self ^ other;
            }
        }
        forward_ref_op_assign! { impl BitXorAssign, bitxor_assign for Wrapping<$t>, Wrapping<$t> }

        #[stable(feature = "rust1", since = "1.0.0")]
        impl BitOr for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn bitor(self, other: Wrapping<$t>) -> Wrapping<$t> {
                Wrapping(self.0 | other.0)
            }
        }
        forward_ref_binop! { impl BitOr, bitor for Wrapping<$t>, Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl BitOrAssign for Wrapping<$t> {
            #[inline]
            fn bitor_assign(&mut self, other: Wrapping<$t>) {
                *self = *self | other;
            }
        }
        forward_ref_op_assign! { impl BitOrAssign, bitor_assign for Wrapping<$t>, Wrapping<$t> }

        #[stable(feature = "rust1", since = "1.0.0")]
        impl BitAnd for Wrapping<$t> {
            type Output = Wrapping<$t>;

            #[inline]
            fn bitand(self, other: Wrapping<$t>) -> Wrapping<$t> {
                Wrapping(self.0 & other.0)
            }
        }
        forward_ref_binop! { impl BitAnd, bitand for Wrapping<$t>, Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

        #[stable(feature = "op_assign_traits", since = "1.8.0")]
        impl BitAndAssign for Wrapping<$t> {
            #[inline]
            fn bitand_assign(&mut self, other: Wrapping<$t>) {
                *self = *self & other;
            }
        }
        forward_ref_op_assign! { impl BitAndAssign, bitand_assign for Wrapping<$t>, Wrapping<$t> }

        #[stable(feature = "wrapping_neg", since = "1.10.0")]
        impl Neg for Wrapping<$t> {
            type Output = Self;
            #[inline]
            fn neg(self) -> Self {
                Wrapping(0) - self
            }
        }
        forward_ref_unop! { impl Neg, neg for Wrapping<$t>,
                #[stable(feature = "wrapping_ref", since = "1.14.0")] }

    )*)
}

wrapping_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }

macro_rules! wrapping_int_impl {
    ($($t:ty)*) => ($(
        impl Wrapping<$t> {
            doc_comment! {
                concat!("Returns the smallest value that can be represented by this integer type.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

assert_eq!(<Wrapping<", stringify!($t), ">>::MIN, Wrapping(", stringify!($t), "::MIN));
```"),
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const MIN: Self = Self(<$t>::MIN);
            }

            doc_comment! {
                concat!("Returns the largest value that can be represented by this integer type.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

assert_eq!(<Wrapping<", stringify!($t), ">>::MAX, Wrapping(", stringify!($t), "::MAX));
```"),
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const MAX: Self = Self(<$t>::MAX);
            }

            doc_comment! {
                concat!("Returns the number of ones in the binary representation of `self`.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

let n = Wrapping(0b01001100", stringify!($t), ");

assert_eq!(n.count_ones(), 3);
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn count_ones(self) -> u32 {
                    self.0.count_ones()
                }
            }

            doc_comment! {
                concat!("Returns the number of zeros in the binary representation of `self`.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

assert_eq!(Wrapping(!0", stringify!($t), ").count_zeros(), 0);
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn count_zeros(self) -> u32 {
                    self.0.count_zeros()
                }
            }

            doc_comment! {
                concat!("Returns the number of trailing zeros in the binary representation
of `self`.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

let n = Wrapping(0b0101000", stringify!($t), ");

assert_eq!(n.trailing_zeros(), 3);
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn trailing_zeros(self) -> u32 {
                    self.0.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 the `<<` shifting
            /// operator!
            ///
            /// # Examples
            ///
            /// Basic usage:
            ///
            /// ```
            /// #![feature(wrapping_int_impl)]
            /// use std::num::Wrapping;
            ///
            /// let n: Wrapping<i64> = Wrapping(0x0123456789ABCDEF);
            /// let m: Wrapping<i64> = Wrapping(-0x76543210FEDCBA99);
            ///
            /// assert_eq!(n.rotate_left(32), m);
            /// ```
            #[inline]
            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
            pub const fn rotate_left(self, n: u32) -> Self {
                Wrapping(self.0.rotate_left(n))
            }

            /// 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 the `>>` shifting
            /// operator!
            ///
            /// # Examples
            ///
            /// Basic usage:
            ///
            /// ```
            /// #![feature(wrapping_int_impl)]
            /// use std::num::Wrapping;
            ///
            /// let n: Wrapping<i64> = Wrapping(0x0123456789ABCDEF);
            /// let m: Wrapping<i64> = Wrapping(-0xFEDCBA987654322);
            ///
            /// assert_eq!(n.rotate_right(4), m);
            /// ```
            #[inline]
            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
            pub const fn rotate_right(self, n: u32) -> Self {
                Wrapping(self.0.rotate_right(n))
            }

            /// Reverses the byte order of the integer.
            ///
            /// # Examples
            ///
            /// Basic usage:
            ///
            /// ```
            /// #![feature(wrapping_int_impl)]
            /// use std::num::Wrapping;
            ///
            /// let n: Wrapping<i16> = Wrapping(0b0000000_01010101);
            /// assert_eq!(n, Wrapping(85));
            ///
            /// let m = n.swap_bytes();
            ///
            /// assert_eq!(m, Wrapping(0b01010101_00000000));
            /// assert_eq!(m, Wrapping(21760));
            /// ```
            #[inline]
            #[unstable(feature = "wrapping_int_impl", issue = "32463")]
            pub const fn swap_bytes(self) -> Self {
                Wrapping(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:
            ///
            /// ```
            /// use std::num::Wrapping;
            ///
            /// let n = Wrapping(0b0000000_01010101i16);
            /// assert_eq!(n, Wrapping(85));
            ///
            /// let m = n.reverse_bits();
            ///
            /// assert_eq!(m.0 as u16, 0b10101010_00000000);
            /// assert_eq!(m, Wrapping(-22016));
            /// ```
            #[stable(feature = "reverse_bits", since = "1.37.0")]
            #[rustc_const_stable(feature = "const_reverse_bits", since = "1.37.0")]
            #[inline]
            #[must_use]
            pub const fn reverse_bits(self) -> Self {
                Wrapping(self.0.reverse_bits())
            }

            doc_comment! {
                concat!("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(wrapping_int_impl)]
use std::num::Wrapping;

let n = Wrapping(0x1A", stringify!($t), ");

if cfg!(target_endian = \"big\") {
    assert_eq!(<Wrapping<", stringify!($t), ">>::from_be(n), n)
} else {
    assert_eq!(<Wrapping<", stringify!($t), ">>::from_be(n), n.swap_bytes())
}
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn from_be(x: Self) -> Self {
                    Wrapping(<$t>::from_be(x.0))
                }
            }

            doc_comment! {
                concat!("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(wrapping_int_impl)]
use std::num::Wrapping;

let n = Wrapping(0x1A", stringify!($t), ");

if cfg!(target_endian = \"little\") {
    assert_eq!(<Wrapping<", stringify!($t), ">>::from_le(n), n)
} else {
    assert_eq!(<Wrapping<", stringify!($t), ">>::from_le(n), n.swap_bytes())
}
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn from_le(x: Self) -> Self {
                    Wrapping(<$t>::from_le(x.0))
                }
            }

            doc_comment! {
                concat!("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(wrapping_int_impl)]
use std::num::Wrapping;

let n = Wrapping(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 = "wrapping_int_impl", issue = "32463")]
                pub const fn to_be(self) -> Self {
                    Wrapping(self.0.to_be())
                }
            }

            doc_comment! {
                concat!("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(wrapping_int_impl)]
use std::num::Wrapping;

let n = Wrapping(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 = "wrapping_int_impl", issue = "32463")]
                pub const fn to_le(self) -> Self {
                    Wrapping(self.0.to_le())
                }
            }

        doc_comment! {
            concat!("Raises self to the power of `exp`, using exponentiation by squaring.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

assert_eq!(Wrapping(3", stringify!($t), ").pow(4), Wrapping(81));
```

Results that are too large are wrapped:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

assert_eq!(Wrapping(3i8).pow(5), Wrapping(-13));
assert_eq!(Wrapping(3i8).pow(6), Wrapping(-39));
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub fn pow(self, exp: u32) -> Self {
                    Wrapping(self.0.wrapping_pow(exp))
                }
            }
        }
    )*)
}

wrapping_int_impl! { usize u8 u16 u32 u64 u128 isize i8 i16 i32 i64 i128 }

macro_rules! wrapping_int_impl_signed {
    ($($t:ty)*) => ($(
        impl Wrapping<$t> {
            doc_comment! {
                concat!("Returns the number of leading zeros in the binary representation of `self`.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

let n = Wrapping(", stringify!($t), "::MAX) >> 2;

assert_eq!(n.leading_zeros(), 3);
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn leading_zeros(self) -> u32 {
                    self.0.leading_zeros()
                }
            }

            doc_comment! {
                concat!("Computes the absolute value of `self`, 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(wrapping_int_impl)]
use std::num::Wrapping;

assert_eq!(Wrapping(100", stringify!($t), ").abs(), Wrapping(100));
assert_eq!(Wrapping(-100", stringify!($t), ").abs(), Wrapping(100));
assert_eq!(Wrapping(", stringify!($t), "::MIN).abs(), Wrapping(", stringify!($t), "::MIN));
assert_eq!(Wrapping(-128i8).abs().0 as u8, 128u8);
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub fn abs(self) -> Wrapping<$t> {
                    Wrapping(self.0.wrapping_abs())
                }
            }

            doc_comment! {
                concat!("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(wrapping_int_impl)]
use std::num::Wrapping;

assert_eq!(Wrapping(10", stringify!($t), ").signum(), Wrapping(1));
assert_eq!(Wrapping(0", stringify!($t), ").signum(), Wrapping(0));
assert_eq!(Wrapping(-10", stringify!($t), ").signum(), Wrapping(-1));
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub fn signum(self) -> Wrapping<$t> {
                    Wrapping(self.0.signum())
                }
            }

            doc_comment! {
                concat!("Returns `true` if `self` is positive and `false` if the number is zero or
negative.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

assert!(Wrapping(10", stringify!($t), ").is_positive());
assert!(!Wrapping(-10", stringify!($t), ").is_positive());
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn is_positive(self) -> bool {
                    self.0.is_positive()
                }
            }

            doc_comment! {
                concat!("Returns `true` if `self` is negative and `false` if the number is zero or
positive.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

assert!(Wrapping(-10", stringify!($t), ").is_negative());
assert!(!Wrapping(10", stringify!($t), ").is_negative());
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn is_negative(self) -> bool {
                    self.0.is_negative()
                }
            }
        }
    )*)
}

wrapping_int_impl_signed! { isize i8 i16 i32 i64 i128 }

macro_rules! wrapping_int_impl_unsigned {
    ($($t:ty)*) => ($(
        impl Wrapping<$t> {
            doc_comment! {
                concat!("Returns the number of leading zeros in the binary representation of `self`.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

let n = Wrapping(", stringify!($t), "::MAX) >> 2;

assert_eq!(n.leading_zeros(), 2);
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub const fn leading_zeros(self) -> u32 {
                    self.0.leading_zeros()
                }
            }

            doc_comment! {
                concat!("Returns `true` if and only if `self == 2^k` for some `k`.

# Examples

Basic usage:

```
#![feature(wrapping_int_impl)]
use std::num::Wrapping;

assert!(Wrapping(16", stringify!($t), ").is_power_of_two());
assert!(!Wrapping(10", stringify!($t), ").is_power_of_two());
```"),
                #[inline]
                #[unstable(feature = "wrapping_int_impl", issue = "32463")]
                pub fn is_power_of_two(self) -> bool {
                    self.0.is_power_of_two()
                }
            }

            doc_comment! {
                concat!("Returns the smallest power of two greater than or equal to `self`.

When return value overflows (i.e., `self > (1 << (N-1))` for type
`uN`), overflows to `2^N = 0`.

# Examples

Basic usage:

```
#![feature(wrapping_next_power_of_two)]
use std::num::Wrapping;

assert_eq!(Wrapping(2", stringify!($t), ").next_power_of_two(), Wrapping(2));
assert_eq!(Wrapping(3", stringify!($t), ").next_power_of_two(), Wrapping(4));
assert_eq!(Wrapping(200_u8).next_power_of_two(), Wrapping(0));
```"),
                #[inline]
                #[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
                           reason = "needs decision on wrapping behaviour")]
                pub fn next_power_of_two(self) -> Self {
                    Wrapping(self.0.wrapping_next_power_of_two())
                }
            }
        }
    )*)
}

wrapping_int_impl_unsigned! { usize u8 u16 u32 u64 u128 }

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;
}