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use crate::num::arithmetic::traits::{WrappingSubMul, WrappingSubMulAssign};
use crate::num::basic::integers::PrimitiveInt;

fn wrapping_sub_mul<T: PrimitiveInt>(x: T, y: T, z: T) -> T {
    x.wrapping_sub(y.wrapping_mul(z))
}

fn wrapping_sub_mul_assign<T: PrimitiveInt>(x: &mut T, y: T, z: T) {
    x.wrapping_sub_assign(y.wrapping_mul(z));
}

macro_rules! impl_wrapping_sub_mul {
    ($t:ident) => {
        impl WrappingSubMul<$t> for $t {
            type Output = $t;

            /// Subtracts a number by the product of two other numbers, wrapping around at the
            /// boundary of the type.
            ///
            /// $f(x, y, z) = w$, where $w \equiv x - yz \mod 2^W$ and $W$ is `Self::WIDTH`.
            ///
            /// # Worst-case complexity
            /// Constant time and additional memory.
            ///
            /// # Examples
            /// See [here](super::wrapping_sub_mul#wrapping_sub_mul).
            #[inline]
            fn wrapping_sub_mul(self, y: $t, z: $t) -> $t {
                wrapping_sub_mul(self, y, z)
            }
        }

        impl WrappingSubMulAssign<$t> for $t {
            /// Subtracts a number by the product of two other numbers in place, wrapping around at
            /// the boundary of the type.
            ///
            /// $x \gets w$, where $w \equiv x - yz \mod 2^W$ and $W$ is `Self::WIDTH`.
            ///
            /// # Worst-case complexity
            /// Constant time and additional memory.
            ///
            /// # Examples
            /// See [here](super::wrapping_sub_mul#wrapping_sub_mul_assign).
            #[inline]
            fn wrapping_sub_mul_assign(&mut self, y: $t, z: $t) {
                wrapping_sub_mul_assign(self, y, z)
            }
        }
    };
}
apply_to_primitive_ints!(impl_wrapping_sub_mul);