simdjson-rust

This crate currently uses simdjson 3.2.3. You can have a try and give feedback.

If you

• find certain APIs are missing
• encounter memory errors
• experience performance degradation

Please submit an issue.

Usage

Add this to your Cargo.toml

# In the `[dependencies]` section
simdjson-rust = "0.3.0"

Then, get started.

use simdjson_rust::prelude::*;
use simdjson_rust::{dom, ondemand};

fn main() -> simdjson_rust::Result<()> {
    let ps = make_padded_string("[0,1,2,3]");

    // ondemand api.
    {
        let mut parser = ondemand::Parser::default();
        let mut doc = parser.iterate(&ps)?;
        let mut array = doc.get_array()?;
        for (index, value) in array.iter()?.enumerate() {
            assert_eq!(index as u64, value?.get_uint64()?);
        }
    }

    // dom api.
    {
        let mut parser = dom::Parser::default();
        let elem = parser.parse(&ps)?;
        let arr = elem.get_array()?;
        for (index, value) in arr.iter().enumerate() {
            assert_eq!(index as u64, value.get_uint64()?);
        }
    }

    Ok(())
}

dom and ondemand

simdjson now offer two kinds of API, dom and ondemand. dom will parsed the whole string while ondemand only parse what you request. Due to ffi, the overhead of ondemand API is relatively high. I have tested lto but it only improves a little :(

Thus it is suggestted that

• use ondemand if you only want to access a specific part of a large json,
• use dom if you want to parse the whole json.

padded_string

simdjson requires the input string to be padded. We must provide a string with capacity = len + SIMDJSON_PADDING. We provide utils to do so.

use simdjson_rust::prelude::*;

fn main() -> simdjson_rust::Result<()> {
    let ps = make_padded_string("[0,1,2,3]");
    let ps = "[0,1,2,3]".to_padded_string();
    // or reuse a buffer.
    let unpadded = String::from("[1,2,3,4]");
    let ps = unpadded.into_padded_string();
    // or load from file.
    let ps = load_padded_string("test.json")?;
    Ok(())
}