risingwave_common/types/
ops.rs

1// Copyright 2025 RisingWave Labs
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7//     http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15use num_traits::Zero;
16
17/// A more general version of [`num_traits::CheckedAdd`] that allows `Rhs` and `Output` to be
18/// different.
19///
20/// Its signature follows [`std::ops::Add`] to take `self` and `Rhs` rather than references used in
21/// [`num_traits::CheckedAdd`]. If we need to implement ops on references, it can be `impl
22/// CheckedAdd<&Bar> for &Foo`.
23pub trait CheckedAdd<Rhs = Self> {
24    type Output;
25    fn checked_add(self, rhs: Rhs) -> Option<Self::Output>;
26}
27
28/// Types already impl [`num_traits::CheckedAdd`] automatically impl this extended trait. Note that
29/// this only covers `T + T` but not `T + &T`, `&T + T` or `&T + &T`, which is used less frequently
30/// for `Copy` types.
31impl<T: num_traits::CheckedAdd> CheckedAdd for T {
32    type Output = T;
33
34    fn checked_add(self, rhs: T) -> Option<Self> {
35        num_traits::CheckedAdd::checked_add(&self, &rhs)
36    }
37}
38
39/// A simplified version of [`num_traits::Signed`].
40/// Unlike `Signed::is_negative` or `f64::is_sign_negative`, this returns `false` for `-0.0` to keep
41/// consistency among integers, decimals and floats.
42pub trait IsNegative: Zero + Ord {
43    fn is_negative(&self) -> bool;
44}
45
46impl<T: Zero + Ord> IsNegative for T {
47    fn is_negative(&self) -> bool {
48        self < &Self::zero()
49    }
50}
risingwave_common/types/ops.rs

risingwave_common/types/
ops.rs
