Crate arithmetic_nonmax 

NonMax provides integer types that cannot be the maximum value of their underlying primitive type.

Memory Optimization

The main benefit of NonMax<T> is that Option<NonMax<T>> has the same size as T. This is achieved through Rust’s “niche optimization”, where the bit pattern of the maximum value is used to represent None.

Primitive	size_of::<T>()	size_of::<Option<T>>()	size_of::<Option<NonMax<T>>>()
u32	4	8	4
i32	4	8	4
u8	1	2	1

Examples

use arithmetic_nonmax::*;
use core::mem::size_of;

// The size of Option<NonMax*> is the same as the underlying primitive type.
assert_eq!(size_of::<Option<NonMaxU32>>(), 4);
assert_eq!(size_of::<Option<u32>>(), 8);

assert_eq!(size_of::<Option<NonMaxI32>>(), 4);
assert_eq!(size_of::<Option<i32>>(), 8);

assert_eq!(size_of::<Option<NonMaxU8>>(), 1);
assert_eq!(size_of::<Option<u8>>(), 2);

Macros

non_max

Creates a NonMax value at compile-time.

Structs

MaxValueError

Error type returned when a value is the maximum for its type.

NonMax

A wrapper type for an integer that cannot be its maximum value.

Type Aliases

NonMaxI8

A signed 8-bit integer that cannot be i8::MAX.

NonMaxI16

A signed 16-bit integer that cannot be i16::MAX.

NonMaxI32

A signed 32-bit integer that cannot be i32::MAX.

NonMaxI64

A signed 64-bit integer that cannot be i64::MAX.

NonMaxI128

A signed 128-bit integer that cannot be i128::MAX.

NonMaxIsize

A signed pointer-sized integer that cannot be isize::MAX.

NonMaxU8

An unsigned 8-bit integer that cannot be u8::MAX.

NonMaxU16

An unsigned 16-bit integer that cannot be u16::MAX.

NonMaxU32

An unsigned 32-bit integer that cannot be u32::MAX.

NonMaxU64

An unsigned 64-bit integer that cannot be u64::MAX.

NonMaxU128

An unsigned 128-bit integer that cannot be u128::MAX.

NonMaxUsize

An unsigned pointer-sized integer that cannot be usize::MAX.