io-buffer 1.0.7

use super::Compression;
use std::io::{Error, ErrorKind, Result};

pub const ERR_LZ4_COMPRESS: &'static str = "lz4_compress_failed";
pub const ERR_LZ4_DECOMPRESS: &'static str = "lz4_decompress_failed";

pub struct LZ4();

impl Compression for LZ4 {
    #[inline]
    fn compress_bound(size: usize) -> usize {
        unsafe { lz4_sys::LZ4_compressBound(size as i32) as usize }
    }

    #[inline]
    fn compress(src: &[u8], dest: &mut [u8]) -> Result<usize> {
        let compressed_len = unsafe {
            lz4_sys::LZ4_compress_default(
                src.as_ptr() as *const libc::c_char,
                dest.as_mut_ptr() as *mut libc::c_char,
                src.len() as i32,
                dest.len() as i32,
            )
        };
        if compressed_len <= 0 {
            Err(Error::new(ErrorKind::Other, ERR_LZ4_COMPRESS))
        } else {
            Ok(compressed_len as usize)
        }
    }

    #[inline]
    fn decompress(src: &[u8], dest: &mut [u8]) -> Result<usize> {
        let decompressed_len = unsafe {
            lz4_sys::LZ4_decompress_safe(
                src.as_ptr() as *const libc::c_char,
                dest.as_mut_ptr() as *mut libc::c_char,
                src.len() as i32,
                dest.len() as i32,
            )
        };
        if decompressed_len <= 0 {
            Err(Error::new(ErrorKind::Other, ERR_LZ4_DECOMPRESS))
        } else {
            Ok(decompressed_len as usize)
        }
    }
}

#[cfg(test)]
mod tests {

    use std::time::Instant;
    //extern crate cpuprofiler;
    use crate::*;
    use std::{
        fs::File,
        io::{Read, Write},
    };

    use super::{super::Compression, LZ4};

    //use self::cpuprofiler::PROFILER;

    #[test]
    fn test_compress() {
        let buf_len: usize = 16 * 1024;
        // prepare
        let mut buffer = Buffer::alloc(buf_len as i32).unwrap();
        rand_buffer(&mut buffer);
        let bound = LZ4::compress_bound(buf_len);
        println!("compress_bound={}", bound);

        // compress
        let mut compressed_buffer = Buffer::alloc(bound as i32).unwrap();
        let compressed_len = LZ4::compress(&buffer, &mut compressed_buffer).unwrap();
        let mut _compressed_buffer = Buffer::alloc(compressed_len as i32).unwrap();
        _compressed_buffer.copy_from(0, &compressed_buffer);
        println!("compressed_len={}", _compressed_buffer.len());

        // decompress
        let mut decompressed_buffer = Buffer::alloc(buf_len as i32).unwrap();
        decompressed_buffer.set_zero(0, decompressed_buffer.len());
        let decompressed_len =
            LZ4::decompress(&_compressed_buffer, &mut decompressed_buffer).unwrap();
        println!("decompressed_len={}", decompressed_len);
        assert_eq!(&decompressed_buffer[0..decompressed_len as usize], &buffer[0..]);
    }

    #[test]
    fn test_benchmark_compress() {
        let loop_cnt: u64 = 1000000;
        // prepare
        let mut buffer = Buffer::alloc(16 * 1024).unwrap();
        rand_buffer(&mut buffer);
        let mut bound = LZ4::compress_bound(16 * 1024);
        bound = (bound + 511) / 512 * 512;

        let mut compressed_len = 0;
        //PROFILER.lock().unwrap().start("./compress.profile").unwrap();
        let start_ts = Instant::now();
        for _i in 0..loop_cnt {
            let mut compressed_buffer = Buffer::alloc(bound as i32).unwrap();

            let mut _compressed_len = LZ4::compress(&buffer, &mut compressed_buffer).unwrap();
            compressed_len = _compressed_len;
        }
        let end_ts = Instant::now();
        //PROFILER.lock().unwrap().stop().unwrap();
        println!(
            "compressed_len={}. compress speed {}(byte)/sec",
            compressed_len,
            ((loop_cnt * 16 * 1024) as f64) / (end_ts.duration_since(start_ts).as_secs_f64())
        );
    }

    #[test]
    fn test_benchmark_decompress() {
        let loop_cnt: u64 = 1000000;
        // prepare
        let mut buffer = Buffer::alloc(16 * 1024).unwrap();
        rand_buffer(&mut buffer);
        let mut bound = LZ4::compress_bound(16 * 1024) as usize;
        println!("compress_bound={}", bound);

        bound = (bound + 511) / 512 * 512;
        let mut compressed_buffer = Buffer::alloc(bound as i32).unwrap();
        let compressed_len = LZ4::compress(&buffer, &mut compressed_buffer).unwrap();

        let mut decompressed_len = 0;
        //PROFILER.lock().unwrap().start("./decompress.profile").unwrap();
        let start_ts = Instant::now();
        for _i in 0..loop_cnt {
            let mut decompressed_buffer = Buffer::alloc(16 * 1024).unwrap();

            let _decompressed_len = LZ4::decompress(
                &compressed_buffer[0..compressed_len as usize],
                &mut decompressed_buffer,
            )
            .unwrap();
            decompressed_len = _decompressed_len;
        }
        let end_ts = Instant::now();
        //PROFILER.lock().unwrap().stop().unwrap();
        println!(
            "decompressed_len={}. decompress speed {}(byte)/sec",
            decompressed_len,
            ((loop_cnt * 16 * 1024) as f64) / (end_ts.duration_since(start_ts).as_secs_f64())
        );
    }

    //#[test]
    #[allow(dead_code)]
    fn test_compatibility() {
        let mut src_buffer = Buffer::alloc(40 * 1024).unwrap();
        let mut dst_buffer = Buffer::alloc(40 * 1024).unwrap();
        let mut src_len: usize = 0;
        let mut dst_len: usize = 0;
        let mut compressed_buffer = Buffer::alloc(40 * 1024).unwrap();
        let mut decompressed_buffer = Buffer::alloc(40 * 1024).unwrap();
        {
            let mut file = File::open("src.lz4").unwrap();
            loop {
                let size = file.read(&mut src_buffer[src_len..]).unwrap();
                if size == 0 {
                    break;
                }
                src_len += size;
            }
            println!("src size={}", src_len);

            let compressed_len = LZ4::compress(&src_buffer, &mut compressed_buffer).unwrap();
            println!("compressed len={}", compressed_len);

            let mut file_res = File::create("dst.lz4.rust").unwrap();
            file_res.write_all(&mut compressed_buffer[0..compressed_len as usize]).unwrap();
        }
        {
            let mut file = File::open("dst.lz4").unwrap();
            loop {
                let size = file.read(&mut dst_buffer[dst_len..]).unwrap();
                if size == 0 {
                    break;
                }
                dst_len += size;
            }
            println!("dst size={}", dst_len);
        }

        let decompressed_len =
            LZ4::decompress(&dst_buffer[0..dst_len], &mut decompressed_buffer).unwrap();
        println!("decompressed_buffer size={}", decompressed_len);
        assert_eq!(&src_buffer[0..src_len], &decompressed_buffer[0..decompressed_len as usize]);
    }
}