Primitive integer marker traits

This crate provides marker traits for primitive integers:

• PrimInt;
• PrimSignedInt;
• PrimUnsignedInt.

Numeric types

Integer types

The unsigned integer types consist of:

u8 | 0 | 2⁸-1 u16 | 0 | 2¹⁶-1 u32 | 0 | 2³²-1 u64 | 0 | 2⁶⁴-1 u128 | 0 | 2¹²⁸-1

The signed two's complement integer types consist of:

i8 | -(2⁷) | 2⁷-1 i16 | -(2¹⁵) | 2¹⁵-1 i32 | -(2³¹) | 2³¹-1 i64 | -(2⁶³) | 2⁶³-1 i128 | -(2¹²⁷) | 2¹²⁷-1

Machine-dependent integer types

The usize type is an unsigned integer type with the same number of bits as the platform's pointer type. It can represent every memory address in the process.

The isize type is a signed integer type with the same number of bits as the platform's pointer type. The theoretical upper bound on object and array size is the maximum isize value. This ensures that isize can be used to calculate differences between pointers into an object or array and can address every byte within an object along with one byte past the end.

usize and isize are at least 16-bits wide.

Example

Cargo.toml

## ...

[dependencies]
just_prim_int = { version = "0.1.0" }

## ...

[features]

## https://doc.rust-lang.org/beta/unstable-book/language-features/marker-trait-attr.html
marker_trait_attr = ["just_prim_int/marker_trait_attr"]

src/main.rs

// Uncomment if you want to conditionally use the feature. Remove otherwise.
// #![cfg_attr(feature = "marker_trait_attr", feature(marker_trait_attr))]

use just_prim_int::PrimInt;

trait MyExtensionTraitForPrimInts: PrimInt {
    // ...
}

fn main() {}

Building, running, and testing

• cargo build <other options> --features marker_trait_attr if you want the feature and cargo build <other options> otherwise;
• cargo run<other options> --features marker_trait_attr if you want the feature and cargo build <other options> otherwise;
• cargo test <other options> --features marker_trait_attr if you want the feature and cargo test <other options> otherwise.

Features

With marker_trait_attr Nightly feature, each of the provided traits also has #[marker] attribute which allows more optimal implementation of PrimInt via two "overlapping" generic impl blocks, one for T: PrimSignedInt and the other for T: PrimUnsignedInt. Without #[marker] attribute, they would be conflicting.

Similar crates by the author:

• epui - Equisized (primitive) unsigned ints for primitive ints: u8 for u8, u16 for i16, etc
• epsi - Equisized (primitive) signed ints for primitive ints
• primitive_promotion - Primitive promotions for primitive numeric types: u16 for u8, i32 for i16, f64 for f32, etc
• is_signed_trait - Trait for IS_SIGNED associated constant
• max_len_base_10_as_usize - Trait offering constant maximum lengths of primitive integers as usize
• min_max_traits - Traits for MIN and MAX associated constants
• as well as others that can be found on crates.io

Alternatives

• num_traits::int::PrimInt - At the moment of writing, num_traits unconditionally provides non-const trait implementations with some useful functions.

License