Compression Options

zesven supports multiple compression methods with configurable levels.

Setting Options

Use WriteOptions to configure compression:

use zesven::{Writer, WriteOptions, Result};

fn main() -> Result<()> {
    let options = WriteOptions::new()
        .level(7)?;  // 0 = store, 9 = maximum compression

    let writer = Writer::create_path("archive.7z")?
        .options(options);

    Ok(())
}

Compression Levels

Level	Description	Speed	Ratio
0	Store (no compression)	Fastest	None
1-3	Fast compression	Fast	Low
4-6	Normal compression	Medium	Medium
7-9	Maximum compression	Slow	High

use zesven::{WriteOptions, Result};

fn main() -> Result<()> {
    // Fast compression for large files
    let fast = WriteOptions::new().level(1)?;

    // Maximum compression for final archives
    let maximum = WriteOptions::new().level(9)?;

    // Balanced (default)
    let balanced = WriteOptions::new().level(5)?;

    Ok(())
}

Compression Methods

LZMA2 (Default)

The default and most commonly used method:

use zesven::{Writer, WriteOptions, codec::CodecMethod, Result};

fn main() -> Result<()> {
    let options = WriteOptions::new()
        .method(CodecMethod::Lzma2)
        .level(7)?;

    let writer = Writer::create_path("archive.7z")?
        .options(options);

    Ok(())
}

LZMA

Original LZMA algorithm:

use zesven::{WriteOptions, codec::CodecMethod, Result};

fn example() -> Result<()> {
    let options = WriteOptions::new()
        .method(CodecMethod::Lzma)
        .level(7)?;
    Ok(())
}

Deflate

Compatible with ZIP, faster but lower ratio:

use zesven::{WriteOptions, codec::CodecMethod, Result};

fn example() -> Result<()> {
    let options = WriteOptions::new()
        .method(CodecMethod::Deflate)
        .level(6)?;
    Ok(())
}

BZip2

Good for text files:

use zesven::{WriteOptions, codec::CodecMethod, Result};

fn example() -> Result<()> {
    let options = WriteOptions::new()
        .method(CodecMethod::BZip2)
        .level(9)?;
    Ok(())
}

PPMd

Excellent for text, high memory usage:

use zesven::{WriteOptions, codec::CodecMethod, Result};

fn example() -> Result<()> {
    let options = WriteOptions::new()
        .method(CodecMethod::PPMd)
        .level(8)?;
    Ok(())
}

Optional Methods

Enable additional methods via feature flags:

[dependencies]
zesven = { version = "1.0", features = ["zstd", "lz4", "brotli"] }

use zesven::{WriteOptions, codec::CodecMethod, Result};

fn example() -> Result<()> {
    // Zstandard - fast with good ratio (level range differs from LZMA)
    let options = WriteOptions::new()
        .method(CodecMethod::Zstd)
        .level_clamped(9);

    // LZ4 - extremely fast
    let options = WriteOptions::new()
        .method(CodecMethod::Lz4);

    // Brotli - excellent ratio for web content
    let options = WriteOptions::new()
        .method(CodecMethod::Brotli)
        .level_clamped(9);

    Ok(())
}

Dictionary Size

The dictionary size is automatically determined based on compression level. Higher levels use larger dictionaries:

Level	Approximate Dictionary	Memory Usage	Best For
1-3	1-4 MB	~12-48 MB	Small files
4-6	4-16 MB	~48-192 MB	Medium files
7-9	16-64 MB	~192-768 MB	Large files

Multi-threading

Parallel compression is enabled by default with the parallel feature. The library automatically uses available CPU cores for LZMA2 compression.

Method Comparison

Method	Speed	Ratio	Memory	Notes
Store	★★★★★	N/A	Low	No compression
LZ4	★★★★★	★★	Low	Extremely fast
Deflate	★★★★	★★★	Low	Good compatibility
Zstd	★★★★	★★★★	Medium	Best speed/ratio
BZip2	★★	★★★★	Medium	Good for text
LZMA	★★	★★★★★	High	Excellent ratio
LZMA2	★★★	★★★★★	High	Multi-threaded LZMA
Brotli	★★	★★★★★	High	Best for web
PPMd	★	★★★★★	Very High	Best for text

See Also

• Creating Archives - Basic archive creation
• Solid Archives - Inter-file compression
• Feature Flags - Enable compression methods