i54_

A 54-bit signed integer abstraction for Rust. Created for easier interop with GraphQL and Javascript, which don't have proper i64-compatible primitives.

Premise

Both Javascript and GraphQL natively represent large (over 32-bit) integers as signed double-precision floating-point values, and do not have primitives representing large integers.

This presents a problem when wanting to represent an integer larger than a u32 in Rust, while maintaining type interop with Javascript and GraphQL.

To make programmer intent clear, we provide an i54 type that should ideally behave similarly to a Rust primitive type, and is intended to represent values that would fit in a hypothetical 54-bit signed integer primitive.

i54 represents the largest signed integer for which all possible values are encoded exactly by an IEEE 754 double-precision floating-point representation. (Encoded roughly as 52 bits in the mantissa, 1 bit derived from the exponent bits, and 1 sign bit.)

Exciting Trait Implementations

• serde - Serialize, Deserialize
• rusqlite (optional) - FromSql, ToSql
• juniper (optional) - GraphQLScalar

Usage

[dependencies]
i54_ = {version = "0.2", features = ["rusqlite", "juniper"]}

use i54_::i54;

fn main() {
    let mut x: i54 = 1.into();
    x += 1.into();
    assert!(x == 2);
}

License: MIT OR Apache-2.0 OR CC0-1.0 (public domain)