Crate brk_vec

Expand description

§BRK Vec

A very small, fast, efficient and simple storable vec which uses mmap2 for speed.

§Features

Get (Rayon compatible)
Push
Update
Insert
Remove

§Disclaimer

Portability will depend on the type of values.

Non bytes/slices types (u8, u16, …) will be read as slice in an unsafe manner (using std::slice::from_raw_parts) and thus have the endianness of the system. On the other hand, &[u8] should be inserted as is.

If portability is important to you, just create a wrapper struct which has custom get, push, … methods and does something like:

impl StorableVecU64 {
    pub fn push(&mut self, value: u64) {
        self.push(&value.to_be_bytes())
    }
}

§Example

use std::{fs, path::Path};

use brk_vec::{Compressed, StorableVec, Version};

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let _ = fs::remove_dir_all("./vec");

    {
        let mut vec: StorableVec<usize, u32> =
            StorableVec::forced_import(Path::new("./vec"), Version::from(1), Compressed::YES)?;

        (0..21_u32).for_each(|v| {
            vec.push(v);
        });
        dbg!(vec.get(0)?);
        dbg!(vec.get(20)?);
        dbg!(vec.get(21)?);

        vec.flush()?;
    }

    {
        let mut vec: StorableVec<usize, u32> =
            StorableVec::forced_import(Path::new("./vec"), Version::from(1), Compressed::YES)?;

        dbg!(vec.get(0)?);
        dbg!(vec.read(0)?);
        dbg!(vec.read(1)?);
        dbg!(vec.read(2)?);
        dbg!(vec.read(20)?);
        dbg!(vec.get(20)?);
        dbg!(vec.read(0)?);

        vec.push(21);
        vec.push(22);
        dbg!(vec.get(20)?);
        dbg!(vec.get(21)?);
        dbg!(vec.get(22)?);
        dbg!(vec.get(23)?);

        vec.flush()?;
    }

    {
        let mut vec: StorableVec<usize, u32> =
            StorableVec::forced_import(Path::new("./vec"), Version::from(1), Compressed::YES)?;

        vec.enable_large_cache();

        dbg!(vec.get(0)?);
        dbg!(vec.get(20)?);
        dbg!(vec.get(21)?);
        dbg!(vec.get(22)?);

        vec.truncate_if_needed(14)?;

        dbg!(vec.get(0)?);
        dbg!(vec.get(5)?);
        dbg!(vec.get(20)?);

        vec.iter(|(_, v)| {
            dbg!(v);
            Ok(())
        })?;

        vec.iter_from(5, |(_, v)| {
            dbg!(v);
            Ok(())
        })?;

        dbg!(vec.collect_range(Some(-5), None)?);
    }

    Ok(())
}