Coverage Report

Created: 2025-07-18 06:52

/rust/registry/src/index.crates.io-6f17d22bba15001f/num-traits-0.2.19/src/ops/euclid.rs
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Source (jump to first uncovered line)
1
use core::ops::{Div, Rem};
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pub trait Euclid: Sized + Div<Self, Output = Self> + Rem<Self, Output = Self> {
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    /// Calculates Euclidean division, the matching method for `rem_euclid`.
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    ///
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    /// This computes the integer `n` such that
7
    /// `self = n * v + self.rem_euclid(v)`.
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    /// In other words, the result is `self / v` rounded to the integer `n`
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    /// such that `self >= n * v`.
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    ///
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    /// # Examples
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    ///
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    /// ```
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    /// use num_traits::Euclid;
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    ///
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    /// let a: i32 = 7;
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    /// let b: i32 = 4;
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    /// assert_eq!(Euclid::div_euclid(&a, &b), 1); // 7 > 4 * 1
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    /// assert_eq!(Euclid::div_euclid(&-a, &b), -2); // -7 >= 4 * -2
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    /// assert_eq!(Euclid::div_euclid(&a, &-b), -1); // 7 >= -4 * -1
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    /// assert_eq!(Euclid::div_euclid(&-a, &-b), 2); // -7 >= -4 * 2
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    /// ```
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    fn div_euclid(&self, v: &Self) -> Self;
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    /// Calculates the least nonnegative remainder of `self (mod v)`.
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    ///
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    /// In particular, the return value `r` satisfies `0.0 <= r < v.abs()` in
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    /// most cases. However, due to a floating point round-off error it can
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    /// result in `r == v.abs()`, violating the mathematical definition, if
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    /// `self` is much smaller than `v.abs()` in magnitude and `self < 0.0`.
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    /// This result is not an element of the function's codomain, but it is the
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    /// closest floating point number in the real numbers and thus fulfills the
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    /// property `self == self.div_euclid(v) * v + self.rem_euclid(v)`
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    /// approximatively.
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    ///
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    /// # Examples
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    ///
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    /// ```
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    /// use num_traits::Euclid;
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    ///
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    /// let a: i32 = 7;
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    /// let b: i32 = 4;
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    /// assert_eq!(Euclid::rem_euclid(&a, &b), 3);
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    /// assert_eq!(Euclid::rem_euclid(&-a, &b), 1);
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    /// assert_eq!(Euclid::rem_euclid(&a, &-b), 3);
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    /// assert_eq!(Euclid::rem_euclid(&-a, &-b), 1);
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    /// ```
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    fn rem_euclid(&self, v: &Self) -> Self;
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    /// Returns both the quotient and remainder from Euclidean division.
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    ///
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    /// By default, it internally calls both `Euclid::div_euclid` and `Euclid::rem_euclid`,
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    /// but it can be overridden in order to implement some optimization.
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    ///
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    /// # Examples
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    ///
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    /// ```
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    /// # use num_traits::Euclid;
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    /// let x = 5u8;
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    /// let y = 3u8;
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    ///
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    /// let div = Euclid::div_euclid(&x, &y);
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    /// let rem = Euclid::rem_euclid(&x, &y);
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    ///
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    /// assert_eq!((div, rem), Euclid::div_rem_euclid(&x, &y));
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    /// ```
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0
    fn div_rem_euclid(&self, v: &Self) -> (Self, Self) {
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0
        (self.div_euclid(v), self.rem_euclid(v))
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0
    }
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}
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macro_rules! euclid_forward_impl {
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    ($($t:ty)*) => {$(
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        impl Euclid for $t {
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            #[inline]
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0
            fn div_euclid(&self, v: &$t) -> Self {
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0
                <$t>::div_euclid(*self, *v)
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0
            }
Unexecuted instantiation: <isize as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <i8 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <i16 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <i32 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <i64 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <i128 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <usize as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <u8 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <u16 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <u32 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <u64 as num_traits::ops::euclid::Euclid>::div_euclid
Unexecuted instantiation: <u128 as num_traits::ops::euclid::Euclid>::div_euclid
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            #[inline]
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0
            fn rem_euclid(&self, v: &$t) -> Self {
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                <$t>::rem_euclid(*self, *v)
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0
            }
Unexecuted instantiation: <isize as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <i8 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <i16 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <i32 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <i64 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <i128 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <usize as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <u8 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <u16 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <u32 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <u64 as num_traits::ops::euclid::Euclid>::rem_euclid
Unexecuted instantiation: <u128 as num_traits::ops::euclid::Euclid>::rem_euclid
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        }
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    )*}
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}
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euclid_forward_impl!(isize i8 i16 i32 i64 i128);
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euclid_forward_impl!(usize u8 u16 u32 u64 u128);
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#[cfg(feature = "std")]
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euclid_forward_impl!(f32 f64);
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#[cfg(not(feature = "std"))]
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impl Euclid for f32 {
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    #[inline]
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0
    fn div_euclid(&self, v: &f32) -> f32 {
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        let q = <f32 as crate::float::FloatCore>::trunc(self / v);
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        if self % v < 0.0 {
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            return if *v > 0.0 { q - 1.0 } else { q + 1.0 };
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0
        }
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        q
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0
    }
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    #[inline]
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    fn rem_euclid(&self, v: &f32) -> f32 {
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        let r = self % v;
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        if r < 0.0 {
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            r + <f32 as crate::float::FloatCore>::abs(*v)
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        } else {
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            r
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        }
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    }
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}
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#[cfg(not(feature = "std"))]
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impl Euclid for f64 {
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    #[inline]
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0
    fn div_euclid(&self, v: &f64) -> f64 {
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        let q = <f64 as crate::float::FloatCore>::trunc(self / v);
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        if self % v < 0.0 {
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            return if *v > 0.0 { q - 1.0 } else { q + 1.0 };
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0
        }
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        q
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0
    }
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    #[inline]
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0
    fn rem_euclid(&self, v: &f64) -> f64 {
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        let r = self % v;
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0
        if r < 0.0 {
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            r + <f64 as crate::float::FloatCore>::abs(*v)
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        } else {
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            r
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        }
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0
    }
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}
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pub trait CheckedEuclid: Euclid {
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    /// Performs euclid division that returns `None` instead of panicking on division by zero
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    /// and instead of wrapping around on underflow and overflow.
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    fn checked_div_euclid(&self, v: &Self) -> Option<Self>;
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    /// Finds the euclid remainder of dividing two numbers, checking for underflow, overflow and
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    /// division by zero. If any of that happens, `None` is returned.
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    fn checked_rem_euclid(&self, v: &Self) -> Option<Self>;
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    /// Returns both the quotient and remainder from checked Euclidean division.
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    ///
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    /// By default, it internally calls both `CheckedEuclid::checked_div_euclid` and `CheckedEuclid::checked_rem_euclid`,
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    /// but it can be overridden in order to implement some optimization.
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    /// # Examples
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    ///
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    /// ```
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    /// # use num_traits::CheckedEuclid;
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    /// let x = 5u8;
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    /// let y = 3u8;
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    ///
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    /// let div = CheckedEuclid::checked_div_euclid(&x, &y);
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    /// let rem = CheckedEuclid::checked_rem_euclid(&x, &y);
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    ///
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    /// assert_eq!(Some((div.unwrap(), rem.unwrap())), CheckedEuclid::checked_div_rem_euclid(&x, &y));
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    /// ```
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0
    fn checked_div_rem_euclid(&self, v: &Self) -> Option<(Self, Self)> {
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        Some((self.checked_div_euclid(v)?, self.checked_rem_euclid(v)?))
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0
    }
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}
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macro_rules! checked_euclid_forward_impl {
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    ($($t:ty)*) => {$(
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        impl CheckedEuclid for $t {
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            #[inline]
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0
            fn checked_div_euclid(&self, v: &$t) -> Option<Self> {
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                <$t>::checked_div_euclid(*self, *v)
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0
            }
Unexecuted instantiation: <isize as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <i8 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <i16 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <i32 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <i64 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <i128 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <usize as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <u8 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <u16 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <u32 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <u64 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
Unexecuted instantiation: <u128 as num_traits::ops::euclid::CheckedEuclid>::checked_div_euclid
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            #[inline]
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0
            fn checked_rem_euclid(&self, v: &$t) -> Option<Self> {
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0
                <$t>::checked_rem_euclid(*self, *v)
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0
            }
Unexecuted instantiation: <isize as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <i8 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <i16 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <i32 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <i64 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <i128 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <usize as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <u8 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <u16 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <u32 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <u64 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
Unexecuted instantiation: <u128 as num_traits::ops::euclid::CheckedEuclid>::checked_rem_euclid
180
        }
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    )*}
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}
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checked_euclid_forward_impl!(isize i8 i16 i32 i64 i128);
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checked_euclid_forward_impl!(usize u8 u16 u32 u64 u128);
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#[cfg(test)]
188
mod tests {
189
    use super::*;
190
191
    #[test]
192
    fn euclid_unsigned() {
193
        macro_rules! test_euclid {
194
            ($($t:ident)+) => {
195
                $(
196
                    {
197
                        let x: $t = 10;
198
                        let y: $t = 3;
199
                        let div = Euclid::div_euclid(&x, &y);
200
                        let rem = Euclid::rem_euclid(&x, &y);
201
                        assert_eq!(div, 3);
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                        assert_eq!(rem, 1);
203
                        assert_eq!((div, rem), Euclid::div_rem_euclid(&x, &y));
204
                    }
205
                )+
206
            };
207
        }
208
209
        test_euclid!(usize u8 u16 u32 u64);
210
    }
211
212
    #[test]
213
    fn euclid_signed() {
214
        macro_rules! test_euclid {
215
            ($($t:ident)+) => {
216
                $(
217
                    {
218
                        let x: $t = 10;
219
                        let y: $t = -3;
220
                        assert_eq!(Euclid::div_euclid(&x, &y), -3);
221
                        assert_eq!(Euclid::div_euclid(&-x, &y), 4);
222
                        assert_eq!(Euclid::rem_euclid(&x, &y), 1);
223
                        assert_eq!(Euclid::rem_euclid(&-x, &y), 2);
224
                        assert_eq!((Euclid::div_euclid(&x, &y), Euclid::rem_euclid(&x, &y)), Euclid::div_rem_euclid(&x, &y));
225
                        let x: $t = $t::min_value() + 1;
226
                        let y: $t = -1;
227
                        assert_eq!(Euclid::div_euclid(&x, &y), $t::max_value());
228
                    }
229
                )+
230
            };
231
        }
232
233
        test_euclid!(isize i8 i16 i32 i64 i128);
234
    }
235
236
    #[test]
237
    fn euclid_float() {
238
        macro_rules! test_euclid {
239
            ($($t:ident)+) => {
240
                $(
241
                    {
242
                        let x: $t = 12.1;
243
                        let y: $t = 3.2;
244
                        assert!(Euclid::div_euclid(&x, &y) * y + Euclid::rem_euclid(&x, &y) - x
245
                        <= 46.4 * <$t as crate::float::FloatCore>::epsilon());
246
                        assert!(Euclid::div_euclid(&x, &-y) * -y + Euclid::rem_euclid(&x, &-y) - x
247
                        <= 46.4 * <$t as crate::float::FloatCore>::epsilon());
248
                        assert!(Euclid::div_euclid(&-x, &y) * y + Euclid::rem_euclid(&-x, &y) + x
249
                        <= 46.4 * <$t as crate::float::FloatCore>::epsilon());
250
                        assert!(Euclid::div_euclid(&-x, &-y) * -y + Euclid::rem_euclid(&-x, &-y) + x
251
                        <= 46.4 * <$t as crate::float::FloatCore>::epsilon());
252
                        assert_eq!((Euclid::div_euclid(&x, &y), Euclid::rem_euclid(&x, &y)), Euclid::div_rem_euclid(&x, &y));
253
                    }
254
                )+
255
            };
256
        }
257
258
        test_euclid!(f32 f64);
259
    }
260
261
    #[test]
262
    fn euclid_checked() {
263
        macro_rules! test_euclid_checked {
264
            ($($t:ident)+) => {
265
                $(
266
                    {
267
                        assert_eq!(CheckedEuclid::checked_div_euclid(&$t::min_value(), &-1), None);
268
                        assert_eq!(CheckedEuclid::checked_rem_euclid(&$t::min_value(), &-1), None);
269
                        assert_eq!(CheckedEuclid::checked_div_euclid(&1, &0), None);
270
                        assert_eq!(CheckedEuclid::checked_rem_euclid(&1, &0), None);
271
                    }
272
                )+
273
            };
274
        }
275
276
        test_euclid_checked!(isize i8 i16 i32 i64 i128);
277
    }
278
}