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# `magic-db`: Precompiled Magic Rules Database

A precompiled database of file type detection rules based on the original `libmagic` project,
optimized and adapted for use with [`pure-magic`](https://crates.io/crates/pure-magic).
This crate provides ready-to-use file type detection capabilities without requiring external rule files.

## Features

- **Precompiled Rules**: Optimized database embedded directly in your binary
- **No External Dependencies**: All rules are included in the compiled crate
- **Enhanced Rules**: Improved and extended versions of the original `libmagic` rules
- **Easy Integration**: Simple one-line access to the compiled database

## Installation

Add `magic-db` to your `Cargo.toml`:

```toml
[dependencies]
magic-db = "0.1"  # Replace with the latest version
pure-magic = "0.1"  # Required peer dependency
```

## Usage

```rust
use magic_db::CompiledDb;
use std::fs::File;
use std::env::current_exe;

fn main() -> Result<(), pure_magic::Error> {
    // Open the precompiled database
    let db = CompiledDb::open()?;

    // Use it to detect file types
    let mut file = File::open(current_exe()?)?;
    let magic = db.first_magic(&mut file, None)?;
    assert!(!magic.is_default());

    println!("File type: {}", magic.message());
    println!("MIME type: {}", magic.mime_type());
    Ok(())
}
```

## About the Rules

This database contains slightly modified versions of the original `libmagic` rules that are available
in the [`src/magdir`](https://github.com/qjerome/magic-rs/tree/main/magic-db/src/magdir) directory of this repository.

Some of the rules have been:
- **Adapted**: Modified to work with the [`pure-magic`](https://crates.io/crates/pure-magic) parser
- **Optimized**: Performance improvements for common file types
- **Extended**: Additional rules were created
- **Fixed**: Corrections to inaccurate or problematic original rules

## Rule Exclusions

The database intentionally excludes the `der` rules (ASN.1/DER encoding rules) because:
- The [`pure-magic`](https://crates.io/crates/pure-magic) parser doesn't support (yet) the specific DER test types
  implemented in the original `libmagic`

## Source Rules

The source magic rules are available in the repository at:
[`src/magdir`](https://github.com/qjerome/pure-magic/tree/main/magic-db/src/magdir)

You can:
1. Browse the rules to understand how file types are detected
2. Suggest improvements by opening issues or pull requests
3. Use these rules as a reference for creating your own custom rules

## License

This project is licensed under the **GPL-3.0 License**.

## See Also

- [`pure-magic`](https://crates.io/crates/pure-magic): The core file type detection library
- [`magic-embed`](https://crates.io/crates/magic-embed): The macro used to create this database
- [`magic`](https://www.man7.org/linux/man-pages/man4/magic.4.html): Expected magic rule format

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