FrozenCore

Custom implementations and core utilities for frozen codebases.

Index

• usage
• ffile
• fmmap
• error
• hints
• crc
• notes

Usage

Add following to your Cargo.toml,

[dependencies]
frozen-core = { version = "0.0.8", default-features = true }

[!TIP] All the features available by default. To disable this, set default-features = false

FrozenFile

FrozenFile is a custom implementation of std::fs::File.

To use the ffile module, add it as a dependency in your Cargo.toml:

[dependencies]
frozen-core = { version = "0.0.8", default-features = false, features = ["ffile"] }

FrozenFile is currently available on the following platforms,

See following example for more details.

FrozenMMap

FrozenMMap is a custom implementation of mmap.

To use the fmmap module, add it as a dependency in your Cargo.toml:

[dependencies]
frozen-core = { version = "0.0.8", default-features = false, features = ["fmmap"] }

FrozenMMap is currently available on the following platforms,

Read the example below for usage details,

use frozen_core::fmmap::{FMCfg, FrozenMMap};

const MID: u8 = 0;

#[repr(C)]
#[derive(Debug)]
struct Meta(u64);

unsafe impl Send for Meta {}
unsafe impl Sync for Meta {}

fn main() {
    let dir = std::path::PathBuf::from("./target/examples");
    let path = dir.join("fm_example.bin");

    let _ = std::fs::remove_file(&path);
    std::fs::create_dir_all(&dir).unwrap();

    let cfg = FMCfg {
        mid: MID,
        initial_count: 1,
        path: path.clone(),
        flush_duration: std::time::Duration::from_micros(100),
    };

    let mmap = FrozenMMap::<Meta>::new(cfg.clone()).unwrap();
    assert_eq!(mmap.slots(), 1);

    let (_, epoch) = mmap.write(0, |m| m.0 = 0x0A).unwrap();
    mmap.wait_for_durability(epoch).unwrap();

    let val = mmap.read(0, |m| m.0).unwrap();
    assert_eq!(val, 10);

    mmap.grow(1).unwrap();
    assert_eq!(mmap.slots(), 2);

    mmap.write(1, |m| m.0 = 0x0F).unwrap();
    drop(mmap); // syncs data

    // reopen & verify
    let reopened = FrozenMMap::<Meta>::new(cfg).unwrap();

    let v0 = reopened.read(0, |m| m.0).unwrap();
    let v1 = reopened.read(1, |m| m.0).unwrap();

    assert_eq!(v0, 0x0A);
    assert_eq!(v1, 0x0F);
}

FrozenErr

FRes & FErr are custom implementation's for result and error propogation.

To use the error module, add it as a dependency in your Cargo.toml:

[dependencies]
frozen-core = { version = "0.0.8", default-features = false, features = ["error"] }

Hints

The hints module provides stable friendly implementations of likely and unlikely branch hints functions.

To use the hints module, add it as a dependency in your Cargo.toml:

[dependencies]
frozen-core = { version = "0.0.8", default-features = false, features = ["hints"] }

Crc

Implementation of CRC32C (Castagnoli polynomial) to compute a 32-bit cyclic redundancy check (CRC) using Castagnoli polynomial, intended for data integrity verification for torn writes and curruption detection

[!WARNING] We assume little-endian target architecture, as big-endian architectures are not supported

[!IMPORTANT] The generated 32-bit CRC is not cryptographically secure, it's intended use only is for data integrity in IO ops

To use the crc module, add it as a dependency in your Cargo.toml:

[dependencies]
frozen-core = { version = "0.0.8", default-features = false, features = ["crc"] }

Crc32C is available on following architectires,

Read the example below for usage details,

use frozen_core::crc::Crc32C;

fn main() {
    let crc = Crc32C::new();

    let b0: [u8; 8] = *b"12345678";
    let b1: [u8; 8] = *b"ABCDEFGH";
    let b2: [u8; 8] = *b"abcdefgh";
    let b3: [u8; 8] = *b"zyxwvuts";

    assert_eq!(crc.crc(&b0), crc.crc(&b0));
    assert_eq!(crc.crc_2x([&b0, &b1]), crc.crc_2x([&b0, &b1]));
    assert_eq!(crc.crc_4x([&b0, &b1, &b2, &b3]), crc.crc_4x([&b0, &b1, &b2, &b3]));
}

Notes

[!IMPORTANT] frozen-core is primarily created for frozen-lab projects. External use is discouraged, but not prohibited, given you asume all the risks.

This project is licensed under the Apache-2.0 and MIT License. See the LICENSE-APACHE and LICENSE-MIT file for more details.

Contributions are welcome! Please feel free to submit a PR or open an issue if you have any feedback or suggestions.