Enumeration of primitive integer kinds

This crate offers PrimIntKind enum whose variants represent kinds of primitive integers.

According to Rust's reference, primitive numeric integer types in Rust are such:

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.

Note: Many pieces of Rust code may assume that pointers, usize, and isize are either 32-bit or 64-bit. As a consequence, 16-bit pointer support is limited and may require explicit care and acknowledgment from a library to support.

Examples

Stable Rust

use prim_int_kind::PrimIntKind;

let res_kind = "u16".parse();
assert_eq!(res_kind, Ok(PrimIntKind::U16));

With const_trait_impl nightly feature

Cargo.toml

# Read more about features here:
# https://doc.rust-lang.org/cargo/reference/features.html
[features]
const_trait_impl = ["prim_int_kind/const_trait_impl"]

src/main.rs

#![cfg_attr(any(doc,test,doctest, feature = "const_trait_impl"), feature(const_trait_impl))]
// Run via `cargo run --features const_trait_impl`

use core::str::FromStr;
use prim_int_kind::{PrimIntKind, PrimIntKindParsingError};

fn main() {
    #[cfg(any(doc,test,doctest, feature = "const_trait_impl"))]
    const res_kind: Result<PrimIntKind, PrimIntKindParsingError> = PrimIntKind::from_str("u16");
    #[cfg(not(any(doc,test,doctest, feature = "const_trait_impl")))]
    let res_kind: Result<PrimIntKind, PrimIntKindParsingError> = PrimIntKind::from_str("u16");
    assert_eq!(res_kind, Ok(PrimIntKind::U16));
}

License