bitemyapp/brotli2-rs

Brotli encoders/decoers for Rust.

Brotli Compression/Decompression for Rust.

This crate is a binding to the official brotli implementation and provides in-memory and I/O streams for Rust wrappers.

Bindings to the official brotli implementation in Rust.

Step 1: Install it

# Cargo.toml
[dependencies]
brotli2 = "0.3"

Step 2: Write code

Here is a simple example:

use std::io::prelude::*;
use brotli2::read::{BrotliEncoder, BrotliDecoder};

// Round trip some bytes from a byte source, into a compressor, into a
// decompressor, and finally into a vector.
let data = "Hello, World!".as_bytes();
let compressor = BrotliEncoder::new(data, 9);
let mut decompressor = BrotliDecoder::new(compressor);

let mut contents = String::new();
decompressor.read_to_string(&mut contents).unwrap();
assert_eq!(contents, "Hello, World!");

Full Example

Let us look at a full Brotli Example.

Step 1. Write Code

Finally we need to write our code as follows:

(a). all-read-write-roundtrips.rs

extern crate brotli2;
extern crate rand;

use brotli2::raw::{compress_buf, decompress_buf};
use brotli2::read;
use brotli2::write;
use brotli2::CompressParams;
use rand::Rng;
use std::io::{Read, Write};

// Used in functions as temporary storage space before producing a vec
const BIGBUF_SIZE: usize = 120 * 1024 * 1024;
static mut BIGBUF: [u8; BIGBUF_SIZE] = [0; BIGBUF_SIZE];

fn main() {
    let v1 = vec![1; 1024];
    let v2 = vec![44; 10 * 1024 * 1024];
    let datas: &[&[u8]] = &[b"", b"a", b"aaaaa", b";", &v1, &v2];
    let mut params = CompressParams::new();
    params.quality(6);
    let params = &params;

    fn bufencode(data: &[u8], params: &CompressParams) -> Vec<u8> {
        let bufref = &mut unsafe { &mut BIGBUF[..] };
        let n = compress_buf(params, data, bufref).unwrap();
        assert!(n > 0 && n <= BIGBUF_SIZE && n == bufref.len());
        bufref.to_owned()
    }
    fn bufdecode(data: &[u8]) -> Vec<u8> {
        let bufref = &mut unsafe { &mut BIGBUF[..] };
        let n = decompress_buf(data, bufref).unwrap();
        assert!(n <= BIGBUF_SIZE && n == bufref.len());
        bufref.to_owned()
    }
    fn ioreadencode(data: &[u8], params: &CompressParams) -> Vec<u8> {
        let mut buf = vec![];
        read::BrotliEncoder::from_params(data, params)
            .read_to_end(&mut buf)
            .unwrap();
        assert!(buf.len() > 0);
        buf
    }
    fn ioreaddecode(data: &[u8]) -> Vec<u8> {
        let mut buf = vec![];
        read::BrotliDecoder::new(data)
            .read_to_end(&mut buf)
            .unwrap();
        buf
    }
    fn iowriteencode(data: &[u8], params: &CompressParams) -> Vec<u8> {
        let mut enc = write::BrotliEncoder::from_params(vec![], params);
        enc.write_all(data).unwrap();
        enc.finish().unwrap()
    }
    fn iowritedecode(data: &[u8]) -> Vec<u8> {
        let mut dec = write::BrotliDecoder::new(vec![]);
        dec.write_all(data).unwrap();
        dec.finish().unwrap()
    }

    let check = |data: &[u8]| {
        let c1 = &bufencode(data, params);
        let c2 = &ioreadencode(data, params);
        let c3 = &iowriteencode(data, params);
        assert!(data == &*bufdecode(c1));
        assert!(data == &*ioreaddecode(c1));
        assert!(data == &*iowritedecode(c1));
        // it's valid for them to be different, but we need to do more work
        if c2 != c1 {
            assert!(data == &*bufdecode(c2));
            assert!(data == &*ioreaddecode(c2));
            assert!(data == &*iowritedecode(c2));
        }
        if c3 != c1 && c3 != c2 {
            assert!(data == &*bufdecode(c2));
            assert!(data == &*ioreaddecode(c2));
            assert!(data == &*iowritedecode(c2));
        }
    };

    for &data in datas.iter() {
        check(data)
    }
    let mut rng = rand::thread_rng();
    for _ in 0..3 {
        let rnum: usize = rng.gen_range(1, 100 * 1024 * 1024);
        let mut buf = vec![0; rnum];
        rng.fill(&mut buf[..]);
        check(&buf)
    }
}

Documentation

Documentation.

Reference

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