Trait sp_runtime::traits::EnsureMulAssign

source · 
pub trait EnsureMulAssign: CheckedMul + PartialOrd<Self> + Zero {
    fn ensure_mul_assign(&mut self, v: Self) -> Result<(), ArithmeticError> { ... }
}
Expand description

Performs self multiplication that returns ArithmeticError instead of wrapping around on overflow.

Provided Methods§

Multiplies two numbers overwriting the left hand one, checking for overflow.

If it fails, ArithmeticError is returned.

Examples
use sp_arithmetic::traits::EnsureMulAssign;

let mut a: i32 = 10;
let b: i32 = 20;

a.ensure_mul_assign(b).unwrap();
assert_eq!(a, 200);
use sp_arithmetic::{traits::EnsureMulAssign, ArithmeticError};

fn overflow() -> Result<(), ArithmeticError> {
    let mut max = u32::MAX;
    max.ensure_mul_assign(2)?;
    Ok(())
}

fn underflow() -> Result<(), ArithmeticError> {
    let mut max = i32::MAX;
    max.ensure_mul_assign(-2)?;
    Ok(())
}

assert_eq!(overflow(), Err(ArithmeticError::Overflow));
assert_eq!(underflow(), Err(ArithmeticError::Underflow));

Implementors§