Crate ni 

ni

Small limited alloc-free named identifier

Usage

This crate provides a type of small, limited, alloc-free string - Name, that can only store:

• Latin lowercase letters 'a'..='z'
• Digits '0'..='9'
• Underscores '_'

The string length cannot exceed 24. This makes it possible to store identifiers very efficiently, such as: key12, hello_world, ni_ident_version2, etc.

The Name type has the same size as &str - two pointers (16 bytes on a 64-bit platform). Unlike &str, it does not carry a lifetime because it stores the data internally. It also implements Copy, meaning it can be duplicated freely without cost since its size is tiny.

This type doesn’t implement many string operations. Instead, it’s mainly used for efficient in-memory storage.

Example

Add the crate to your project. You can enable a feature to get serialization/deserialization support:

cargo add ni -F serde

Currently, the crate supports serde and bincode. This is optional if you only need to store many small strings in memory.

Now we can efficiently parse data with many identifiers, for example a schema with arbitrary fields like a HashMap:

use {
    ni::Name,
    std::{collections::HashMap, io},
};

fn main() -> io::Result<()> {
    let json = r#"
    {
        "some_data": 10,
        "key0": 1,
        "key1": 2,
        "key2": 3,
        "key3": 4
    }"#;

    let data: HashMap<Name, u32> = serde_json::from_str(&json)?;
    println!("{data:#?}");

    Ok(())
}

Macros

name

Creates a name from the string. Panics when name is invalid.

Structs

DecodedName

Return type from the decode method used to obtain a slice or string.

Name

Small limited alloc-free named identifier.

Enums

Error

The name creation error.