Trait sp_runtime::traits::EnsureAdd

pub trait EnsureAdd: EnsureAddAssign {
    // Provided method
    fn ensure_add(self, v: Self) -> Result<Self, ArithmeticError> { ... }
}

Performs addition that returns ArithmeticError instead of wrapping around on overflow.

Provided Methods

fn ensure_add(self, v: Self) -> Result<Self, ArithmeticError>

Adds two numbers, checking for overflow.

If it fails, ArithmeticError is returned.

Similar to CheckedAdd::checked_add() but returning an ArithmeticError error.

Examples

use sp_arithmetic::traits::EnsureAdd;

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

assert_eq!(a.ensure_add(b), Ok(30));

use sp_arithmetic::{traits::EnsureAdd, ArithmeticError};

fn overflow() -> Result<(), ArithmeticError> {
    u32::MAX.ensure_add(1)?;
    Ok(())
}

fn underflow() -> Result<(), ArithmeticError> {
    i32::MIN.ensure_add(-1)?;
    Ok(())
}

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

Implementors

impl<T> EnsureAdd for Twhere T: EnsureAddAssign,