This crate provides two types of bounded integer.

The bounded_integer! macro allows you to define your own bounded integer type, given a specific (inclusive) range it inhabits. For example:

bounded_integer! {
    struct MyInteger(0, 7);
}
let num = MyInteger::new(5).unwrap();
assert_eq!(num, 5);

This macro supports both structs and enums. See the examples module for the documentation of generated types.

You can also create ad-hoc bounded integers via types in this library that use const generics, for example:

let num = <BoundedU8<0, 7>>::new(5).unwrap();
assert_eq!(num, 5);

These integers are shorter to use as they don't require a type declaration or explicit name. However due to the limits of const generics, they may not implement some traits – namely [Default], bytemuck’s Zeroable and zerocopy’s FromZeros. Also, unlike their macro counterparts they will not be subject to niche layout optimizations.

All the integers in this crate depend only on libcore and so work in #![no_std] environments.

By default, no crate features are enabled.

• std: Interopate with std — implies alloc. Enables the following things:
  • An implementation of Error for ParseError.
• alloc: Interopate with alloc. Has no effect currently.
• macro: Enable the bounded_integer! macro.
• arbitrary1: Implement Arbitrary for the bounded integers. This is useful when using bounded integers as fuzzing inputs.
• bytemuck1: Implement Contiguous and NoUninit for all bounded integers, and Zeroable for macro-generated bounded integers that support it.
• num-traits02: Implement Bounded, AsPrimitive, FromPrimitive, NumCast, ToPrimitive, CheckedAdd, CheckedDiv, CheckedMul, CheckedNeg, CheckedRem, CheckedSub, MulAdd, SaturatingAdd, SaturatingMul and SaturatingSub for all bounded integers.
• serde1: Implement Serialize and Deserialize for the bounded integers, making sure all values will never be out of bounds.
• zerocopy: Implement IntoBytes and Immutable for all bounded integers, Unaligned for ones backed by u8 or i8, and FromZeros for suitable macro-generated ones.
• step_trait: Implement the Step trait which allows the bounded integers to be easily used in ranges. This will require you to use nightly and place #![feature(step_trait)] in your crate root if you use the macro.